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prof. Ing. Radislav Šmíd, Ph.D.

Všechny publikace

Theoretical Approaches to Signal Processing for Optimizing Blade Tip Timing Probes Arrangement

  • Autoři: Mekhalfia, M., Procházka, P., prof. Ing. Radislav Šmíd, Ph.D., Tchawou Tchuisseu, E.B.
  • Publikace: 6th International Conference on Advances in Signal Processing and Artificial Intelligence (ASPAI' 2024). Lviv: International Frequency Sensor Association (IFSA), 2024. p. 64-66. ISSN 2938-5350. ISBN 978-84-09-60540-8.
  • Rok: 2024
  • Pracoviště: Katedra měření
  • Anotace:
    This theoretical study focuses on optimizing the positioning of blade tip timing probes to enhance the analysis of turbomachinery performance. The accurate measurement of blade vibrations is crucial for assessing the health and efficiency of turbines and compressors. By strategically placing the probes at specific locations along the blade tips, we aim to improve data collection precision and reliability. This paper explains the theoretical background of optimized approaches for determining the optimal probe positions, aiming to maximize data accuracy and minimize errors in vibration analysis.

Non-intrusive Current-based Fault Detection of Electro-mechanical Actuators with Brushed DC Motors

  • DOI: 10.24425/mms.2022.140040
  • Odkaz: https://doi.org/10.24425/mms.2022.140040
  • Pracoviště: Katedra měření
  • Anotace:
    This paper proposes data-based fault detection methods for an electromechanical actuator (EMA) with a brushed DC motor. The jam and winding short faults are considered in the study as the most prominent EMA faults. The fault detection is based on evaluating the properties of the motor current, considering the basic electromechanical parameters of EMAs. The main advantages are a non-intrusive approach utilising a commonly accessible motor current measurement, simple configurability, and the ability to detect faults under varying operation modes of EMA, including changes of speed, load, or movement profiles. The proposed methods have been evaluated with a custom testing system, and the results have proven the performance of the proposed approach to detect faults under varying operating conditions in industrial applications.

Automated testing system for electro-mechanical actuators used in aviation

  • Pracoviště: Katedra měření
  • Anotace:
    This article presents an automated testing system for electromechanical actuators used in aviation. The paper describes the parameters and properties of the system and the possibilities of its use. Based on the data obtained from the system, a method for detecting actuator jam is proposed.

Short-range Wirelessly Powered Sensor Network: Concept and Initial Measurement

  • DOI: 10.1109/I2MTC43012.2020.9128629
  • Odkaz: https://doi.org/10.1109/I2MTC43012.2020.9128629
  • Pracoviště: Katedra měření
  • Anotace:
    With rapid improvements in the reduction of power consumption of modern electronic in recent decades, a batteryless operation can also be achieved in small sensor networks. A common way to power such devices is by energy harvesting from sunlight, heat source, or vibrations. In applications, where none of them can be used, the alternative is to supply energy using wireless power transfer (WPT). Comparing a couple of WPT technologies, a radio frequency (RF) was chosen as a suitable candidate for powering a sensor network. In this paper, elements of the sensor network using RF energy powering in the lower frequency ISM (industrial, scientific and medical) band and wireless communication in higher frequency ISM band are proposed, and based on this concept, a sensor node with RF energy harvester is developed. For development purposes, a single-node network with RF power transmitter is built-up, and initial measurements are described. Results show that in the parallel configuration of transmitter and receiver antenna, the wave-character of RF radiation has a significant impact on the received signal strength, and proper positioning of the receiver relative to the transmitter must be ensured for sufficient energy harvesting in a real application. Another measurement proves this assertion and shows that misalignment to the peak of RF wave in closer distance from transmitter would lead to lower performance even in comparison to a node in the greater distance, but more precisely aligned.

Virtual Mass Flow Rate Sensor Using a Fixed-Plate Recuperator

  • DOI: 10.1109/JSEN.2019.2894526
  • Odkaz: https://doi.org/10.1109/JSEN.2019.2894526
  • Pracoviště: Katedra měření
  • Anotace:
    The mass flow rate inside heating, ventilation, and air-conditioning units provides important information for fault detection and diagnosis (FDD) and for performance monitoring. Most commercial units are not equipped with physical flow rate sensors, and virtual sensors (VS) offer an alternative that provides improved FDD performance. This paper presents the virtual mass flow sensor for an air handling unit with a recuperator (a fixed-plate heat exchanger). The VS is based on the heat exchange process inside the recuperator. It estimates the mass flow of air only on the basis of temperature readings from the inlet and the outlet of the recuperator. Two different approaches to the design of the VS model are described here. The first approach uses a simplified physical description of the recuperator, and the second approach uses knowledge of the recuperator performance curve. Laboratory experiments have confirmed that the proposed VS can be utilized as a substitute for a physical mass flow rate sensor for monitoring and for fault detection.

Edge computing and machine condition monitoring

  • Autoři: prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: The Fifteenth International Conference on Condition Monitoring and Machinery Failure Prevention Technologies. Northamption: British Institute of Non-Destructive Testing ( BINDT ), 2018. p. 213-216. ISBN 9780903132701.
  • Rok: 2018
  • Pracoviště: Katedra měření
  • Anotace:
    Vibration-based machine condition monitoring uses fast sampling rates for digitization of signals from accelerometers and similar sensors. The resulting high amount of data exceeds the capacity of standard wireless communication channels. Performing data processing at the edge of the network, near the source of the data (so-called edge computing), can reduce the communications bandwidth needed between sensors and the central unit. In the paper, we describe the prototype of vibration analysis module with machine-to-machine communication capability using LoRaWAN.

Application system design - energy optimisation

  • Autoři: prof. Ing. Radislav Šmíd, Ph.D., Stluka, P., Ferreira, L.L.
  • Publikace: IoT Automation: Arrowhead Framework. New Yourk: CRC Press, 2017. p. 211-246. ISBN 978-1-4987-5675-4.
  • Rok: 2017
  • DOI: 10.1201/9781315367897
  • Odkaz: https://doi.org/10.1201/9781315367897
  • Pracoviště: Katedra měření
  • Anotace:
    This book presents an in-depth description of the Arrowhead Framework and how it fosters interoperability between IoT devices at service level, specifically addressing application. The Arrowhead Framework utilizes SOA technology and the concepts of local clouds to provide required automation capabilities such as: real time control, security, scalability, and engineering simplicity. Arrowhead Framework supports the realization of collaborative automation; it is the only IoT Framework that addresses global interoperability across multiplet SOA technologies. With these features, the Arrowhead Framework enables the design, engineering, and operation of large automation systems for a wide range of applications utilizing IoT and CPS technologies.

Condition monitoring and Industry 4.0

  • Autoři: prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: WCCM 2017. Northamption: British Institute of Non-Destructive Testing ( BINDT ), 2017. p. 1-4. ISBN 9781510844759.
  • Rok: 2017
  • Pracoviště: Katedra měření
  • Anotace:
    The omnipresent use of sensors, the spread of wireless communication and computer networks, the deployment of autonomous robots and smart machines, as well as increased computing power at lower cost, has the chance to transform the manufacturing and production and consequently bring new challenges to condition monitoring.

Condition monitoring using IoT

  • Pracoviště: Katedra měření
  • Anotace:
    With the advent of low-cost microcontroller-based monitoring devices connected to the Internet, there are novel possibilities of condition monitoring using new information sources. In this paper, we describe the architecture of an IoT-based system for monitoring of degradations of building equipment and illustrate the employment of local and cloud processing.

Improved multisensors signal processing

  • Autoři: Roshchupkina, N., Balovsiak, S., Sachenko, A., Roshchupkin, O., prof. Ing. Radislav Šmíd, Ph.D., Kochan, V.
  • Publikace: ELNANO 2015 - Conference Proceedings. Kyiv: National Technical University of Ukraine, 2015. pp. 341-346. ISBN 978-1-4673-6534-5.
  • Rok: 2015
  • DOI: 10.1109/ELNANO.2015.7146906
  • Odkaz: https://doi.org/10.1109/ELNANO.2015.7146906
  • Pracoviště: Katedra měření
  • Anotace:
    The algorithm of the program was created to approximate the output signal of multisensor (MS) using the functional dependency of MS output voltage from MS operating frequency for a fixed thickness of tested films, the output voltage of the MS film thickness at a fixed frequency. The MS data obtained by sine wave eddy current measurement. It is investigated the influence of different type of function approximation accuracy of MS signals. It is shown that the smallest approximation error obtained using as polynomial function of the summation of first power polynomial and exponential function. This is indicates correctness and efficiency of noise reduction. This research is aimed to investigate and find effective, specialized and cheap tool for multisensor signals processing.

Method of Ensuring an Interchangeability of the Ultraviolet Radiation Sensors During a Transition to its Individual Conversion Function

  • Autoři: Roshchupkin, O., prof. Ing. Radislav Šmíd, Ph.D., Sachenko, A., Kochan, V., Roshchupkina, N.
  • Publikace: Proceedings of the 2015 IEEE 8th International Conference on Intelligent Data Acquisition and Advanced Computing Systems: Technology and Applications (IDAACS). Ternopil: Ternopil National Economic University, 2015. pp. 113-119. ISBN 9781467383615.
  • Rok: 2015
  • DOI: 10.1109/IDAACS.2015.7340710
  • Odkaz: https://doi.org/10.1109/IDAACS.2015.7340710
  • Pracoviště: Katedra měření
  • Anotace:
    This article show the results of the synthesis of the ultraviolet measurement system using photodiode. It was synthesized the generalized structure of the system and the scheme of its measurement channels. The measurement accuracy is increased by transition to individual conversion functions as a photodiode as well as measurement scheme. It is also proposed the scheme of data processing and evaluated the error of measurement of ultraviolet irradiation.

Ontology based automated design of FDD systems

  • Pracoviště: Katedra měření
  • Anotace:
    Fault Detection or performance monitoring systems for HVAC (Heating, Ventilation, Air Conditioning) infrastructures in buildings have similar concepts. Customization of such systems (adaptation for different equipment, population of multiple units etc.) is labor- and time-consuming task, up to now provided manually. We propose an automated process for designing of FDD systems using context-sensitive combining the information from Building Information Model and ontology-based device descriptions.

A Distributed Fault Detection System based on IWSN for Machine Condition Monitoring

  • Autoři: Neužil, J., Kreibich, O., prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: Industrial Informatics, IEEE Transactions on. 2014, 10(2), 1118-1123. ISSN 1551-3203.
  • Rok: 2014
  • DOI: 10.1109/TII.2013.2290432
  • Odkaz: https://doi.org/10.1109/TII.2013.2290432
  • Pracoviště: Katedra měření
  • Anotace:
    This paper introduces a novel framework for Industrial Wireless Sensor Networks used for Machine Condition Monitoring. Our approach enables the use of state-of-the-art computationally intensive classifiers in computationally weak sensor network nodes. The key idea is to split data acquisition, classifier building and training, and the operation phase, between different units. Computationally demanding processing is carried out in the central unit, while other tasks are distributed to the sensor nodes using over-the-air programming. The system is autonomously trained on the healthy state of a machine, and then monitors a change in behavior which indicates a faulty state. Thanks to one-class classification, there is no need to introduce the faulty state of the machine in the training phase. We extend the diagnostic capability of the system using dynamic changes in the data acquisition and classification parts of the program in the sensor nodes. This enables the system to react to ambiguous machine states by temporarily changing the diagnostic focus. Compressing the information in the individual sensor nodes provided by in-node classification allows us to transmit only the classification result, instead of full signal waveforms. This enables the MCM system to be deployed with a large number of nodes, even with high sampling rates. The proposed concept was evaluated in IRIS IWSN by means of a rotary machine simulator.

Development of Precision Information Measuring System for Ultraviolet Radiation

  • Autoři: Roshchupkin, O., prof. Ing. Radislav Šmíd, Ph.D., Sachenko, A., Kochan, V.
  • Publikace: Advances in Electrical and Computer Engineering. 2014, 14(3), 101-106. ISSN 1582-7445.
  • Rok: 2014
  • DOI: 10.4316/AECE.2014.03013
  • Odkaz: https://doi.org/10.4316/AECE.2014.03013
  • Pracoviště: Katedra měření
  • Anotace:
    Results of studying the neural network method are presented to reduce the amount of calibration points for the multisensor (MS), in particular for the photodiode. This allows transmitting to the MS individual conversion function and provides the high accuracy of measurement. The structure of synthesized information-measuring system and its measuring channel has created for implementing of the proposed approach. A structural scheme is proposed as well for values transmitting the etalon measures to measuring systems. Its used to determine the errors of photodiodes, as those which are produced for customers. This assures the interchangeability of sensors when using the individual conversion function.

HVAC Test Bed for Research and Development of Virtual Sensors for Condition Monitoring

  • Autoři: Horyna, V., prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: 11th International Conference on Condition Monitoring and Machinery Failure Prevention Technologies, CM 2014 / MFPT 2014. Northamption: British Institute of Non-Destructive Testing ( BINDT ), 2014, pp. 731-735. ISBN 978-1-63439-505-2.
  • Rok: 2014
  • Pracoviště: Katedra měření
  • Anotace:
    Large amount of electric energy consumption in office buildings is caused by HVAC (heating, ventilating and air-conditioning) system. For that reason new methods for reduction of operating costs in HVAC systems are searched. Early detection of HVAC failures can reduce these costs. Advanced diagnostic methods need large amounts of sensors. This cause a problem, because HVAC systems include the smallest possible number of physical sensors (primary for automatic closed-loop control). The concept of virtual sensors enables to increase number of sensors without a need of installation of new physical sensors. For creating of virtual sensor is necessary to reveal the mathematical model describing functional relation between estimated value and measured value (or values). For development of these mathematical models (relations) an experimental HVAC system was created. It is special test bed consisting of standard HVAC unit complemented of large sensor network. This paper describes this HVAC test bed and datasets measured within this test bed.

Quality-Based Multiple Sensor Fusion in an Industrial Wireless Sensor Network for MCM

  • Autoři: Kreibich, O., Neužil, J., prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: IEEE Transactions on Industrial Electronics. 2014, 61(9), 4903-4911. ISSN 0278-0046.
  • Rok: 2014
  • DOI: 10.1109/TIE.2013.2293710
  • Odkaz: https://doi.org/10.1109/TIE.2013.2293710
  • Pracoviště: Katedra měření
  • Anotace:
    The early alert monitoring system for an effective scheduled maintenance strategy based on a wireless technology requires reliable transfer of the diagnostic information between the sensor and the gateway. This paper presents an IWSN-based machine condition monitoring (MCM) system capable of overcoming a false indication caused by temporary loss of data, signal interference or invalid data. We use multi-sensor fusion driven by a quality parameter, produced by each sensor node according to the data history outliers and the actual state of the node. The fusion node provides a quality evaluation on its output as well. This novel approach enables the propagation of information about the uncertainty of a measured value from the source node to the sink node. Thus potential degradation of acquired or transferred diagnostic information is minimized. Instead of raw data the signal features are transferred, so that bandwidth savings are improved rapidly. The proposed concept was experimentally verified on real WSN hardware. The performance evaluated using the Signal-to-Noise ratio and false alarm rate detection demonstrates the effectiveness of the proposed approach.

Virtual sensors for HVAC condition monitoring

  • Autoři: prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: 11th International Conference on Condition Monitoring and Machinery Failure Prevention Technologies, CM 2014 / MFPT 2014. Northamption: British Institute of Non-Destructive Testing ( BINDT ), 2014, ISBN 978-1-63439-505-2.
  • Rok: 2014
  • Pracoviště: Katedra měření
  • Anotace:
    The paper discusses applications of virtual sensors as tools for condition monitoring of HVAC equipment in buildings. Virtual sensors (sometimes called as inferential or soft sensors) can serve as replacement for physical sensors in advanced HVAC FDD systems, where additional physical sensors are expensive to buy, install and maintain. Typical physically non-sensed variables are analyzed and their virtual sensing for condition monitoring purposes is discussed.

Multisensors Signal Processing Using ANFIS

  • Autoři: Roschupkina, N., Sachenko, A., Roshchupkin, O., Kochan, V., prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: IDAACS 2013 - Proceedings of the 2013 IEEE 7th International Conference on Intelligent Data Acquisition and Advanced Computing Systems. Berlin: IEEE, 2013, pp. 315-318. pozn.: CD má na nálepce jiné ISBN: 978-1-4799-1427-2. ISBN 978-1-4799-1426-5.
  • Rok: 2013
  • Pracoviště: Katedra měření
  • Anotace:
    An improved algorithm of intelligent data processing by integrating the modified identification method of individual characteristic curve along with the adaptive neuro-fuzzy inference system (ANFIS) was proposed. The results of data prediction with training the ANFIS system and the different number of training epochs are described. The proposed approach provides the high accuracy of data prediction as well as low neural network training error.

Multisensors Signal Processing Using Microcontroller and Neural Networks Identification

  • Autoři: Roshchupkin, O., prof. Ing. Radislav Šmíd, Ph.D., Kochan, V., Sachenko, A.
  • Publikace: Sensors and Transducers. 2013, 24(8), 1-6. ISSN 1726-5479.
  • Rok: 2013
  • Pracoviště: Katedra měření
  • Anotace:
    An approach of multisensor signals processing at microprocessor or 8 bit microcontrollers is showed in this paper. This approach is based on multisensor individual conversion function or individual characteristic curve identification method with using of neural networks. It allow to reduce an amount of calibration points and increase the precision of identification with comparatively to well known methods. The realization of this approach was made on developed system for ultraviolet level measurement based on 8-bit microcontrollers.

The Lift-off Effect in Eddy Currents Thickness Modeling and Measurement

  • Autoři: Král, J., prof. Ing. Radislav Šmíd, Ph.D., Ramos, H.M.G., Ribeiro, A.L.
  • Publikace: IEEE Transactions on Instrumentation and Measurement. 2013, 62(1), 2043-2049. ISSN 0018-9456.
  • Rok: 2013
  • DOI: 10.1109/TIM.2013.2247713
  • Odkaz: https://doi.org/10.1109/TIM.2013.2247713
  • Pracoviště: Katedra měření
  • Anotace:
    This paper uses a linear transformer model to investigate the effect of the lift-off on the results of the thickness measurement of non-ferromagnetic metallic plates using Eddy currents. To assess the validity of the model, results are compared with experimental data obtained with a giant magnetoresistive (GMR) sensor probe.

Virtual Sensors for Diagnostics of Valve

  • Autoři: Horyna, V., prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: 10TH INTERNATIONAL CONFERENCE ON CONDITION MONITORING AND MACHINERY FAILURE PREVENTION TECHNOLOGIES CM2013/MFPT2013. Oxfordshire: Coxmoor Publishing Co., 2013, ISBN 9781629939926.
  • Rok: 2013
  • Pracoviště: Katedra měření
  • Anotace:
    The new trend in the modern technical diagnostic tends to diagnose virtually any important part of a device with minimizing of number of the new sensors for doing this. Tnis effort leads to the idea of virtual sensors. Using indirect measurement and a model of diagnosed system, we can obtain information of system compoments status without necessity of new physical sensors. This paper suggests novel method for monitoring of electromagnetic valve proper function. The method is based on monitoring of valve switching current waveform. This method is able to diagnose seizing of the valve, spring crack or defect of the valve coil. The incomplete valve operation can be also diagnosed as well. Proposed method is based on the comparison between measured current waveform during the valve switching with anticipated behavior, described by mathematic model of the diagnosed valve.

Virtual Sensors for Machine Condition Monitoring

  • Autoři: Horyna, V., prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: 10TH INTERNATIONAL CONFERENCE ON CONDITION MONITORING AND MACHINERY FAILURE PREVENTION TECHNOLOGIES CM2013/MFPT2013. Oxfordshire: Coxmoor Publishing Co., 2013, ISBN 9781629939926.
  • Rok: 2013
  • Pracoviště: Katedra měření
  • Anotace:
    This paper gives an overview of principles and ideas in virtual sensors used for machine condition monitoring. Virtual sensors (inferential or soft sensors) are prospective replacement for physical sensors in various situations: physical sensor is expensive to buy, install or maintain, no room for sensor placement or measured quantity is unavailable for sensing. Discussion includes model driven, data driven and hybrid paradigms.

Advanced Signal Processing in Wireless Sensor Networks for MCM

  • Autoři: Neužil, J., Kreibich, O., prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: CM 2012 / MFPT 2012 - The 9-th International Conference on Condition Monitoring and Machinery Failure Prevention Technologies. Oxfordshire: Coxmoor Publishing Co., 2012. pp. 1087-1093. ISBN 978-1-62276-433-4.
  • Rok: 2012
  • Pracoviště: Katedra měření
  • Anotace:
    Wireless Sensor Networks (WSNs) have a broad use in machine condition monitoring and generally in condition based maintenance. Their main benefit is in easy installation in areas where a classical wired system is not applicable or is inconvenient. It saves significant resources that would be spent in heavy-duty wired connection. Such system is reconfigurable - it is easy to adapt its functionality. It usually creates a distributed system with much more sensing points than in a classical wired centralized system. It brings better resistance to unfavorable effects and better robustness. To exploit all WSNs capabilities it is necessary to apply suitable advanced signal processing methods. This paper brings the overview of tools, techniques and methods for WSNs applied for machine condition monitoring. It is demonstrated the state-of-the art applications and pointed the future direction of this promising technology.

Application of Wireless Sensor Networks in Condition Monitoring of Rotating Devices

  • Autoři: Kreibich, O., Neužil, J., prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: CM 2012 / MFPT 2012 - The 9-th International Conference on Condition Monitoring and Machinery Failure Prevention Technologies. Oxfordshire: Coxmoor Publishing Co., 2012. pp. 1094-1101. ISBN 978-1-62276-433-4.
  • Rok: 2012
  • Pracoviště: Katedra měření
  • Anotace:
    Wireless approach to acquire diagnostic signals (vibration, temperature, input current etc.) from mechanical devices and their components could be more than an interesting alternative to conventional wire systems with a central data logger or analyser. It is evident that wirelessly mounted sensors bring benefits in easier installation, manipulation and maintenance. However bare substitution of wires for a radio communication with enormous stream of raw data between sensors and a central unit has many drawbacks like power consumption, noise resistance and hardware requirement. Decentralised systems called wireless sensor network appears more suitable in this way. In WSN each sensor node is equipped by microcontroller to control sensor setting, radio and network communication. These systems are not primarily designed to sense rapidly changing signals but presence of microcontroller in node offers a possibility to integrate a suitable signal processing methods mainly data fusion to extract and transmit only useful signal or information.

Comparison of Cascade and Concurrent Signal Denoising Methods

  • Autoři: Kubínyi, M., prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: 2011 IEEE International Ultrasonics Symposium (IUS). New York: IEEE, 2012. pp. 516-519. ISSN 1948-5719. ISBN 978-1-4577-1252-4.
  • Rok: 2012
  • DOI: 10.1109/ULTSYM.2011.0124
  • Odkaz: https://doi.org/10.1109/ULTSYM.2011.0124
  • Pracoviště: Katedra měření
  • Anotace:
    An~important issue in ultrasonic nondestructive testing is the~detection of flaw echoes in the~presence of background noise created by instrumentation and by clutter noise. Signal averaging, autoregressive analysis, spectrum analysis, matched filtering and the~wavelet transform have all been used to filter noise in~ultrasonic signals. Widely-used wavelet threshold estimation algorithms are not designed for EMAT pulse-echo signals, and therefore do not exploit their unique impulse nature. The~approaches to ultrasonic signal filtering proposed in this paper are based on wavelet denoising combined with other denoising algorithms. The~denoising algorithms are combined with a~knowledge ultrasonic echo detection and system frequency characteristics. The~compared methods were evaluated on signals measured with EMAT probes and under various Signal-to-Noise Ratio (SNR) conditions, and they~outperform the~wavelet transform with the~UNIVERSAL threshold estimation method.

Reducing the Calibration Points of Multisensors

  • Autoři: Roshchupkin, O., prof. Ing. Radislav Šmíd, Ph.D., Kochan, V., Sachenko, A.
  • Publikace: 9th International Multi-Conference on Systems, Signals and Devices (SSD). Piscataway: IEEE, 2012. pp. 1-6. ISBN 978-1467-3159-0-6.
  • Rok: 2012
  • DOI: 10.1109/SSD.2012.6197987
  • Odkaz: https://doi.org/10.1109/SSD.2012.6197987
  • Pracoviště: Katedra měření
  • Anotace:
    Goal of this paper is to develop the method identification of multisensors characteristic curve using neural networks and minimize the number of calibration points required to find an appropriate characteristic curve for the input-to-output relationship of multisensors. A proposed original method illustrates how to improve the prediction accuracy of calibration results for multisensors despite the high level of random error.

Acceleration of Acoustic Emission Signal Processing Algorithms using CUDA Standard

  • DOI: 10.1016/j.csi.2010.12.003
  • Odkaz: https://doi.org/10.1016/j.csi.2010.12.003
  • Pracoviště: Katedra měření
  • Anotace:
    This paper proposes a way to accelerate signal processing methods for acoustic emission and to accelerate similarity calculation using the Graphic Processing Unit (GPU). GPU-based accelerators are an affordable High Performance Computing (HPC) solution which can be used in any industrial workstation or laptop. They are therefore suitable for onsite AE monitoring.

Detecting Dominant Resonant Modes of Rolling Bearing Faults Using the Niching Genetic Algorithm

  • Autoři: Dočekal, A., prof. Ing. Radislav Šmíd, Ph.D., Kreidl, M., Krpata, P.
  • Publikace: Mechanical Systems and Signal Processing. 2011, 25(7), 2559-2572. ISSN 0888-3270.
  • Rok: 2011
  • DOI: 10.1016/j.ymssp.2011.02.012
  • Odkaz: https://doi.org/10.1016/j.ymssp.2011.02.012
  • Pracoviště: Katedra měření
  • Anotace:
    In this paper we propose an improvement of methods for adaptive selection of frequency bands containing transients which indicate the presence of the dominant resonant modes of rolling bearing faults using niching genetic algorithm optimization. The main aim of this approach is to diagnose the condition of the bearings and to be able to recognize faults on various parts of bearings and possible combinations of faults. Because the vibration signals corresponding to faults on bearings are typically transients with a wide frequency range occurring around the excited mechanical resonant modes and drowned in the acquired vibration signals, it is necessary to emphasize these excited transients using a matched bank of filters.

EMAT Noise Suppression Using Information Fusion in Stationary Wavelet Packets

  • Autoři: Kubínyi, M., Kreibich, O., Neužil, J., prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control (UFFC). 2011, 58(5), 1027-1037. ISSN 0885-3010.
  • Rok: 2011
  • DOI: 10.1109/TUFFC.2011.1903
  • Odkaz: https://doi.org/10.1109/TUFFC.2011.1903
  • Pracoviště: Katedra měření
  • Anotace:
    An important issue in ultrasonic nondestructive testing is the~detection of flaw echoes in the presence of background noise created by instrumentation and by clutter noise. Signal averaging, autoregressive analysis, spectrum analysis, matched filtering and the~wavelet transform have all been used to filter noise in~ultrasonic signals. Widely-used wavelet threshold estimation algorithms are not designed for EMAT pulse-echo signals, and therefore do not exploit their unique impulse nature. The~approach to ultrasonic signal filtering proposed in this paper is based on stationary wavelet packet denoising with a~threshold influenced by several information sources: a~statistical echo detection, the~amplitude distribution of the~wavelet transform coefficients, and apriori known system frequency characteristics.

Information Fusion in Wireless Sensor Networks for MCM

  • Autoři: prof. Ing. Radislav Šmíd, Ph.D., Kreibich, O.
  • Publikace: THE 8TH INTERNATIONAL CONFERENCE ON CONDITION MONITORING AND. Dublin: BINDT, US Society for Machinery Failure Prevention Technology, 2011. pp. 672-677. ISBN 978-1-61839-014-1.
  • Rok: 2011
  • Pracoviště: Katedra měření
  • Anotace:
    Wireless sensor networks are perspective tools for machine condition monitoring. Output of wireless sensor node is affected by several degradations (sensor aging) and noises from various sources (impulsive noise from switching of inductive loads, internal electronic noise etc ). We propose a weak redundancy approach to increasing the sensor system performance. Multiple sensor nodes are measuring similar mixtures of signals of interest and fuzzy based information fusion is used for improvement of resulting signal quality. The proposed system can be efficiently implemented in wireless sensor network nodes.

Novel S-Transform Information Fusion for Filtering Ultrasonic Pulse-Echo Signals

  • Autoři: Kubínyi, M., Kreibich, O., Neužil, J., prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: Przeglad Elektrotechniczny. 2011, 87(1), 290-295. ISSN 0033-2097.
  • Rok: 2011
  • Pracoviště: Katedra měření
  • Anotace:
    Direct evaluation of ultrasonic signals requires data analyses with an acceptable level of noise. Ultrasonic signals represent a specific category of time domain signals to be analyzed. In order to increase a difference between the level of noise and the amplitude of the ultrasonic pulse a suitable method for signal filtering has to be used. Within this article we discuss and evaluate a novel signal denoising method. The S-transform for signal analysis and processing was used. This transformation has been recently introduced for ultrasonic echo analyses. Proposed transformation represents an intermediate stage between the Fourier transform analysis and the wavelet transform analysis. In order to filter ultrasonic signals from the Electromagnetic Acoustic Transducer (EMAT) with a high level of noise, new, different approach in signal filtering was developed based on an information fusion. Suggested method is able to process the pulse-echo signal in its full complexity.

Rotary Machine Condition Monitoring Using One-Class Classification in Wireless Sensor Networks

  • Autoři: Neužil, J., prof. Ing. Radislav Šmíd, Ph.D., Kreibich, O.
  • Publikace: THE 8TH INTERNATIONAL CONFERENCE ON CONDITION MONITORING AND. Dublin: BINDT, US Society for Machinery Failure Prevention Technology, 2011. pp. 702-710. ISBN 978-1-61839-014-1.
  • Rok: 2011
  • Pracoviště: Katedra měření
  • Anotace:
    In this paper we introduce the system for machine condition monitoring (MCM) based on the Wireless Sensors Network (WSN). In the proposed system the vibrational behaviour of a rotary machine is sensed by the nodes of the network. In the each node samples are pre-processed and suitable features describing the faulty behaviour of a machine are extracted, then the features input to the classifier. An one-class classifier implemented in the each node creates an intermediate classification result. From these results is in the network created by voting and combining procedures the final decision about a machine condition. This approach may bring many benefits compared to classical wired centralized systems, i.e. easier deployment, robustness and gives a good overall view of a machine condition.

Thickness Measurement Using Transient Eddy Current Techniques

  • Autoři: Král, J., prof. Ing. Radislav Šmíd, Ph.D., Ramos, H.M.G., Ribeiro, A.L.
  • Publikace: I2MTC - 2011 IEEE International Instrumentation and Measurement Technology Conference. Binjiang: IEEE, 2011. pp. 138-142. ISSN 1091-5281. ISBN 978-1-4244-7935-1.
  • Rok: 2011
  • Pracoviště: Katedra měření
  • Anotace:
    This paper describes a pulsed eddy current (PEC) based non-destructive testing system used for experimental evaluation of material thickness and properties. Both classical and modern sensing methods of magnetic field have been carried out. An inductive as well as a giant magnetoresistive sensor based (GMR) probe have been used for sensing and the results obtained are presented and compared. The use of GMRs for this type of application is innovative and the post processing method too, since it evaluates the thicknesses of the conductive samples or of its non-conductive coatings, from the values obtained with the integration of measured signals.

Ultrasonic Denoising with a Modified Wavelet Filter

  • Autoři: Kubínyi, M., prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: Intelligent Data Acquisition and Advanced Computing Systems (IDAACS). Piscataway: IEEE, 2011, pp. 479-482. ISBN 978-1-4577-1423-8.
  • Rok: 2011
  • Pracoviště: Katedra měření
  • Anotace:
    Development of the wavelets has been focused on signal thresholding methods and adjustment to new sensor systems. We would like to present a fast algorithm for enhancing wavelet denoising performance. This is done by implementing an ideal band-pass filter over common wavelet thresholding process. We propose a new technique for signal denoising which is concentrated on the described ultrasonic signals. The proposed algorithm was verified on ultrasonic sensors which are widely used in the measurement of dimensions and quality of a product. Results showed a significant improvement in wavelet denoising performance over previously published wavelet denoising algorithms.

Ultrazvuková defektoskopie

  • Autoři: Kreidl, M., prof. Ing. Radislav Šmíd, Ph.D., Matz, V., Štarman, S.
  • Publikace: Praha: Starmans Electronics s.r.o., 2011. ISBN 978-80-254-6606-3.
  • Rok: 2011
  • Pracoviště: Katedra měření
  • Anotace:
    Kniha přináší přehled teorie a metod pro ultrazvukové nedestruktivní zkoušení a přináší popis pokročilého zpracování signálů.

Chirp and Multi-frequency Eddy Current Non-destructive Evaluation

  • Autoři: prof. Ing. Radislav Šmíd, Ph.D., Král, J., Mrázek, M.
  • Publikace: IMEKO Symposium TC-4, TC-19 & IWADC Instrumentation for the ICT Area. Košice: Technical University of Košice, 2010, pp. 114-117. ISBN 978-1-61782-338-1.
  • Rok: 2010
  • Pracoviště: Katedra měření
  • Anotace:
    This paper describes an eddy current (EC) based non-destructive testing system used for experimental verification of optimized chirp signal. The time-frequency content of the EC driving signal is synthesized with respect to material properties. We are expecting an improvement in sensitivity of crack and corrosion detection.

Comparison of Time-Frequency Distributions for Pulse-Echo Ultrasonic Evaluation and Filtering

  • Autoři: Kubínyi, M., prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: IMEKO Symposium TC-4, TC-19 & IWADC Instrumentation for the ICT Area. Košice: Technical University of Košice, 2010, pp. 30. ISBN 978-1-61782-338-1. Available from: http://www.imeko.tuke.sk/papers.html
  • Rok: 2010
  • Pracoviště: Katedra měření
  • Anotace:
    For a direct evaluation of ultrasonic signals it is necessary to analyse data with an acceptable level of noise. Ultrasonic signals represent a specific category of time domain signals to be analysed. In order to increase difference between the level of noise and the amplitude of the ultrasonic pulse a proper method for data differentiation has to be used. Within this article are discussed and compared two time-frequency distributions. The first approach is via wavelet transform. The second proposed method is S-transform. This transformation has been recently introduced for ultrasonic echo analyses. This tool represents intermediate stage between the Fourier transform analysis and the Wavelet transform analysis. In order to filter ultrasonic signals from Electromagnetic Acoustic transducer with a high level of noise, new, different approach was developed. The result showed complexity of the ultrasonic signal and noise in case of the Electromagnetic Acoustic Transducer.

Comparison of Ultrasound Non-destructive Inspection Techniques on the Basis of Sensitivity and Detection Reliability

  • Autoři: Kubínyi, M., prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: Workshop 2010. Praha: České vysoké učení technické v Praze, 2010, pp. 134-135. CTU Reports. ISBN 978-80-01-04513-8.
  • Rok: 2010
  • Pracoviště: Katedra měření
  • Anotace:
    Ultrasonic nondestructive evaluation is one of the most widely used method for nondestructive testing in Czech Republic. While the main goal of this technique is to find and characterize flaws inside tested structure it is necessary to know sensitivity of this method. Previously published articles used Probability of detection curves (PoD) to evaluate new inspection techniques in order to better characterize their characteristics. Laboratory research program is focused on signal processing methods which improve sensitivity and reliability of new ultrasonic systems. It has been also published how to model PoD curves for TOFD measurements. In this paper we will present signal processing method and it´s verification for Electro Magnetic Acoustic Transducer automatic PoD curve construction.

Distributed Classification in Wireless Sensor Networks for Machine Condition Monitoring

  • Autoři: Neužil, J., prof. Ing. Radislav Šmíd, Ph.D., Kreibich, O.
  • Publikace: The Seventh International Conference on Condition Monitoring and Machinery Failure Prevention Technologies. Dublin: MFPT + BINDT (The British Institute of Non-destructive Testing), 2010, pp. 1-11. ISBN 978-1-901892-33-8.
  • Rok: 2010
  • Pracoviště: Katedra měření
  • Anotace:
    The use of Wireless Sensor Network (WSN) in Machine Condition Monitoring (MCM) can bring many advantages compare to a classical approach. WSN is composed from nodes, where each node contains microcontroller, RF transmitter and sensor(s). The advantage of WSN is mainly in flexibility and easy installation in hardly accessible areas. However, the significant disadvantage is a limited data flow from nodes to central controller. This is related to low transmission capability and to effort to minimize energy consumption of each node. Hence it is not suitable to send the raw data from each node and interpret them in one the very last (main) node of a network. In this paper we propose an MCM system based on WSN using data pre-processing and feature extraction implemented in nodes of WSN. The idea behind is to run the learning and operation phases on different platforms (PC versus WSN).

E-learning Tools for Education and Training in Diagnostics and Machine Condition Monitoring

  • Autoři: Kreibich, O., prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: Proceedings of the 2nd International Conference on Computer Supported Education - CSEDU 2010. Setúbal: INSTICC Press, 2010. pp. 357-361. ISBN 978-989-674-024-5.
  • Rok: 2010
  • Pracoviště: Katedra měření
  • Anotace:
    This paper presents an integration of e-learning into an existing course of diagnostics, machine condition monitoring (MCM) and nondestructive testing (NDT), educated at our university. A diagnostics education belongs to field of study where e-learning is used less commonly than in other fields for its necessity to attending a laboratory. Laboratory education, forms an integral part of many university courses, mainly in natural and technical university education, are necessary to improve students' knowledge by experiments with laboratory samples and devices. There could arise a problem for foreign and distance students, who cannot physically attend these courses. Therefore the aim of this project is presentation of a possible solution on the example of laboratory electro-mechanical device fully accessible via Internet.

Gearbox Condition Monitoring Using Advanced Classifiers

  • Pracoviště: Katedra měření
  • Anotace:
    The paper describes gearbox condition monitoring using Kohonen Neural Network and Adaptive Network-based Fuzzy Inference System.

Improvement of Localization of AE Clusters based on Similarity of AE Events

  • Autoři: Říha, L., prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: Progress in acoustic emission XV, Proceedings of the 20th International Acoustic Emission Symposium. Jokohama: Japanese Society for Non-Destructive Inspection, 2010, pp. 1-5. ISBN 978-4-931018-15-0.
  • Rok: 2010
  • Pracoviště: Katedra měření
  • Anotace:
    This paper describes a method for improvement of Localization of AE Clusters based on Similarity of AE Events.

Integration of Condition Monitoring and NDT into Manufacturing Systems - Tools and Approaches

  • Autoři: prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: The Seventh International Conference on Condition Monitoring and Machinery Failure Prevention Technologies. Dublin: MFPT + BINDT (The British Institute of Non-destructive Testing), 2010, ISBN 978-1-901892-33-8.
  • Rok: 2010
  • Pracoviště: Katedra měření
  • Anotace:
    Research and development in knowledge-based manufacturing paradigm (EU FP7 Factories of the Future, Manufuture platform etc.) create needs for integration of condition monitoring and NDT into manufacturing systems. The paper will be aimed on review of tools and approaches for incorporation of MCM and NDT to holistic manufacturing engineering concepts. The requirements for future testing and monitoring systems can be summarized as follows: high scalability, modularity and flexibility, plug-and-play architecture, distributed operation, and run-time reconfigurability. Basic principles of reconfigurable monitoring and testing will be summarized, enabling technologies as a multi-agent systems and wireless sensor networks will be analyzed along with data fusion and distributed signal processing methods.

Evaluation of Genetic Algorithm Based Methods Used for Separation of Tapered Rolling Bearing Vibration

  • Autoři: Dočekal, A., prof. Ing. Radislav Šmíd, Ph.D., Kreidl, M.
  • Publikace: CM 2009 and MFPT 2009 - The Sixth International Conference on Condition Monitoring and Machinery Failure Prevention Technologies. Dublin: BINDT, US Society for Machinery Failure Prevention Technology, 2009. p. 1190-1201.
  • Rok: 2009
  • Pracoviště: Katedra měření
  • Anotace:
    This paper is focused on evaluation of genetic algorithm based methods used to separate vibrations produced by tapered rolling bearings. A novel method for evaluation of the stochastic search was proposed. This method enables to rate the statistical reliability of achieved results.

Evaluation of Methods Used for Separation of Vibration Produced by Gear Transmissions

  • Pracoviště: Katedra měření
  • Anotace:
    This paper evaluates methods used for separating vibrations produced by a gear transmission from the vibration signal acquired on the gearbox.

Separation of Rolling Bearing Vibration Based on Genetic Algorithm

  • Autoři: Dočekal, A., Krpata, P., prof. Ing. Radislav Šmíd, Ph.D., Kreidl, M.
  • Publikace: ICSV16 - The 16th International Congress on Sound and Vibration. Krakow: International Institute of Acoustics and Vibration (IIAV), 2009, ISBN 978-83-60716-71-7.
  • Rok: 2009
  • Pracoviště: Katedra měření
  • Anotace:
    This paper deals with separation of vibrations produced by different faults on rolling bearings. The main goals in view are separation of vibration produced by rolling bearings from the background noise, and separation of particular faults arisen on the damaged bearing. A method for bearing vibration signal separation based on the genetic algorithm was proposed. Standard genetic algorithm and its non-dominated extension were implemented.

Signal-to-Noise Ratio Enhancement Based on Wavelet Filtering in Ultrasonic Testing

  • DOI: 10.1016/j.ultras.2009.05.010
  • Odkaz: https://doi.org/10.1016/j.ultras.2009.05.010
  • Pracoviště: Katedra měření
  • Anotace:
    In ultrasonic non-destructive testing of materials with a coarse-grained structure the scattering from the grains causes backscattering noise, which masks flaw echoes in the measured signal. Several filtering methods have been proposed for improving the signal-to-noise ratio. In this paper we present a comparative study of methods based on the wavelet transform. Experiments with stationary, discrete and wavelet packet de-noising are evaluated by means of signal-to-noise ratio enhancement. Measured and simulated ultrasonic signals are used to verify the proposed de-noising methods. For comparison, we use signal-to-noise ratio enhancement related to fault echo amplitudes and filtering efficiency specific for ultrasonic signals. The best results in our setup were achieved with the wavelet packet de-noising method.

Avoidance of Speckle Noise in Laser Vibrometry by the Use of Kurtosis Ratio: Application to Mechanical Fault Diagnostics

  • DOI: 10.1016/j.ymssp.2007.08.008
  • Odkaz: https://doi.org/10.1016/j.ymssp.2007.08.008
  • Pracoviště: Katedra teorie obvodů, Katedra měření
  • Anotace:
    This paper presents a statistical technique to enhance vibration signals measured by Laser Doppler Vibrometry (LDV). The method has been optimised for LDV signals measured on bearings of universal electric motors and applied to quality control of washing machines. Inherent problems of LDV are addressed, particularly the speckle noise occurring when rough surfaces are measured. The presence of speckle noise is detected using a new scalar indicator Kurtosis Ratio (KR), specifically designed to quantify the amount of random impulses generated by this noise. The KR is a ratio of the standard kurtosis and a robust estimate of kurtosis, thus indicating the outliers in the data. Since it is inefficient to reject the signals affected by the speckle noise, an algorithm for selecting an undistorted portion of a signal is proposed. The algorithm includes band-pass filtering and segmentation of the signal, as well as thresholding of the KR computed for each filtered signal segment.

Development of a Switched Integrator Amplifier for High-accuracy Optical Measurements

  • Autoři: Mountford, J., Porrovecchio, G., Šmíd, M., prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: Applied Optics. 2008, 47(31), 5821-5828. ISSN 0003-6935.
  • Rok: 2008
  • DOI: 10.1364/AO.47.005821
  • Odkaz: https://doi.org/10.1364/AO.47.005821
  • Pracoviště: Katedra měření
  • Anotace:
    In the field of low flux optical measurements, the development and use of large area silicon detectors is becoming more frequent. The current/voltage conversion of their photocurrent presents a set of problems for traditional transimpedance amplifiers. The switched integration principle overcomes these limitations. We describe the development of a fully characterized current-voltage amplifier using the switched integrator technique. Two distinct systems have been developed in parallel at the United Kingdom's National Physical Laboratory (NPL) and Czech Metrology Institute (CMI) laboratories. We present the circuit theory and best practice in the design and construction of switched integrators. In conclusion the results achieved and future developments are discussed.

EMAT - Eddy Currents and Ultrasound

  • Autoři: Kubínyi, M., prof. Ing. Radislav Šmíd, Ph.D., Ribeiro, A.L.
  • Publikace: 2008 PEGASUS-AIAA Student Conference. Prague: Czech Technical University, 2008.
  • Rok: 2008
  • Pracoviště: Katedra měření
  • Anotace:
    EMAT (Electro-Magnetic Acoustic Transducer) systems combine eddy currents and static magnetic field to generate ultrasound inside inspected material. Initial blind zone (dead zone) for crack sensitivity reduces EMAT usage for thicker parts of airframe. Eddy current plays in this zone main role. Distribution of the field in this area will be evaluated. Simplified mathematical model then will be represented for better imagination of whole ultrasound generation and detection process.

EMAT Applied in The Aviation Industry

  • Autoři: Kubínyi, M., prof. Ing. Radislav Šmíd, Ph.D., Kreidl, M.
  • Publikace: ICAS 2008 - Proceedings. Anchorage: International Council of the Aeronautical Sciences, 2008. ISBN 0-9533991-9-2.
  • Rok: 2008
  • Pracoviště: Katedra měření
  • Anotace:
    The goal of this paper is to show the result of the real measurement with EMAT system in the aviation industry. Common nondestructive evaluation (NDE) techniques used in the field are the eddy current and the ultrasound inspection. EMAT (Electro-Magnetic Acoustic Transducers) system is a combination of these two methods and exhibit an advantage in non-contact principle of the eddy current and detection depth of the ultrasound NDE. In the cooperation with the main Czech aircraft producer Aero Vodochody Czech Republic, the main Czech aircraft service company LOM Praha s.p. and Czech Airlines Company Department of Quality control stressed parts of aircrafts were analyzed. The samples from these companies cover significant part of currently used civil and military aircrafts.

Localization of the Best Measuring Point for Gearwheel Behaviour Testing Using Group of Adaptive Models Evolution

  • Autoři: Dočekal, A., Dynybyl, V., Kreidl, M., prof. Ing. Radislav Šmíd, Ph.D., Žák, P.
  • Publikace: Measurement Science Review. 2008, 8(2), 42-45. ISSN 1335-8871.
  • Rok: 2008
  • Pracoviště: Katedra měření
  • Anotace:
    This paper deals with signal processing for vibration analysis of the gear transmission. The main goal was localization of the best measuring point on the gearbox housing, which could provide the highest sensitivity to gearwheels vibration. Vibration measured at some selected points on the gearbox housing was analysed using methods of spectral analysis. The important frequencies in the vibration spectra and a value of their importance were estimated using Group of Adaptive Models Evolution.

Novel Eddy Current and EMAT Probes Performance Comparison

  • Autoři: Kubínyi, M., prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: Sborník z 8. mezinárodní vědecké konference Měření, diagnostika a spolehlivost palubních soustav letadel. Brno: Univerzita obrany, Fakulta vojenských technologií, 2008, pp. 33-38. ISBN 978-80-7231-555-0.
  • Rok: 2008
  • Pracoviště: Katedra měření
  • Anotace:
    We want to evaluate performance of two experimental NDE (Nondestructive evaluation) systems, eddy current and EMAT (Electro-Magnetic Acoustic Transducer). The both of them want to be applied in aircraft maintenance and the both of them search for flaws beneath the tested object surface. Each one has an advantage that they don´t need direct contact with the specimen. With the development of these diagnostic methods we want to deal with corrosion detection. We want to be able to test hardly accessible sides of aircraft structures without dismounting or special preparation of the surface. We tested aluminum plate with cracks built from the same material as is used for airframe. We made a study of the probes sensitivity.

Ultrasonic Signal De-noising Using Dual Filtering Algorithm

  • Autoři: Matz, V., Kreidl, M., prof. Ing. Radislav Šmíd, Ph.D., Štarman, S.
  • Publikace: The 17th World Conference on Non-destructive Testing - Proceedings. Shanghai: Chinese Society for Non-destructive Testing, 2008.
  • Rok: 2008
  • Pracoviště: Katedra měření
  • Anotace:
    This paper describes the proposal of dual filtering algorithm used for ultrasonic A-scan signal de-noising The dual filtering algorithm, presented in this paper, is based on application of efficient denoising algorithms as Wiener filter and discrete wavelet transform. The Wiener filter based group delay statistics is presented and the best parameters are searched. The discrete wavelet transform algorithm with different mother wavelets, threshold levels and threshold rules is also presented.

Wiener Filter Estimation Methods for Rolling Bearing Vibration Analysis

  • Autoři: Dočekal, A., Kreidl, M., prof. Ing. Radislav Šmíd, Ph.D., Říha, L.
  • Publikace: ICSV15 - 15th International Congress on Sound and Vibration. Daejeon: The Korean Society for Noise and Vibration Engineering (KSNVE), 2008. ISBN 978-89-961284-1-0.
  • Rok: 2008
  • Pracoviště: Katedra měření
  • Anotace:
    This document deals with rotating machinery vibration analysis in order to separate vibrations produced by rolling bearings. The vibration signals were filtered using different Wiener filters. The paper is focused on comparison of efficiency which can be reached by usage of different Wiener filter estimation methods. The Wiener filter estimation method based on group delay statistics estimation (Group Delay Moving Standard Deviation), the method based on Power Spectral Density (PSD) (Standard Deviation of Power Spectral Density Autocorrelation), and Spectral Kurtosis were inspected and compared.

Wiener Filtering for Vibration Analysis of Gear Transmission

  • Autoři: Dočekal, A., Lingsong, H., prof. Ing. Radislav Šmíd, Ph.D., Kreidl, M.
  • Publikace: The 37th International Congress & Exhibition on Noise Control Engineering. Shanghai: i-ince, 2008, pp. 1-9. ISBN 978-16-056-0989-8.
  • Rok: 2008
  • Pracoviště: Katedra měření
  • Anotace:
    This paper deals with usage of Wiener filters for vibration analysis of gear transmissions.

A Comparative Evaluation between Algorithms Used for De-Noising of EMAT Signals

  • Autoři: Štarman, S., Matz, V., Kreidl, M., prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: International Congress on Ultrasonics. Vienna: Vienna University of Technology, 2007, pp. 110.
  • Rok: 2007
  • Pracoviště: Katedra měření
  • Anotace:
    This paper presents a comparative evaluation between algorithms used for de-noising of ultrasonic EMAT signals in the field of non-destructive testing.

Adaptive Filtering Methods in New Type of Ultrasound Nondestructive Evaluation

  • Autoři: Kubínyi, M., prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: POSTER 2007. Praha: České vysoké učení technické v Praze, Fakulta elektrotechnická, 2007.
  • Rok: 2007
  • Pracoviště: Katedra měření
  • Anotace:
    New type of Nondestructive Evaluation (NDE) method is Ultrasound Electromagnetic Acoustic Transducer (EMAT). Regarding to low EMAT conversion efficiency there are needed filtration methods of acquired signal. The acquired signal from EMAT probe is weaker than from piezoelectric transducer. Benefits of classical FIR and IIR band pass filtering methods are not enough for noisy EMAT signal. Good alternative for linear filtering is Wiener filter design. Adaptive algorithm could be more sensitive for small defects. Wavelet transformation is widely used in non-linear digital filtering in ultrasound defectoscopy. Benefits of filtering with wavelet transformation were proved on classical ultrasound and will be examinated on EMAT signals. For signal evaluation is used Matlab software environment.

An Experimental Study of Ultrasonic Signal De-Noising Based on Wavelet Algorithms

  • Autoři: Matz, V., Litseva, E., prof. Ing. Radislav Šmíd, Ph.D., Kreidl, M.
  • Publikace: International Congress on Ultrasonics. Vienna: Vienna University of Technology, 2007, pp. 111.
  • Rok: 2007
  • Pracoviště: Katedra měření
  • Anotace:
    This paper describes a results of an experimental study of ultrasonic signal de-noising based on various wavelet algorithms.

Discrimination of Acoustic Emission Events Based on Similarity of Describing Parameters

  • Autoři: Říha, L., Bláha, J., prof. Ing. Radislav Šmíd, Ph.D., Dočekal, A.
  • Publikace: IV Conferencia Panamericana de END, CD Proceedings. Buenos Aires: Asociación Argentina de Ensayos No Destructivos y Estructurales, 2007, ISBN 978-987-23957-0-4.
  • Rok: 2007
  • Pracoviště: Katedra měření
  • Anotace:
    This paper describes a new method developed for the discrimination of acoustic emission (AE) events based on the similarity of their parameters. The method should help to locate the sources of AE events which are related to failure of the material's integrity. Early detection of crack growth is critical for the prevention of catastrophic failure. The problem is that during long-term monitoring of construction, many AE events captured are disturbances. If standard methods of discrimination are used, a number of clusters of AE events are located. The developed method uses the specific behavior of AE sources generated by the crack propagation in the material to discriminate between those sources and the disturbances. The discrimination is based on the similarity of AE parameters. The proposed method was validated on real data from measurements of two different chemical reactors. The reference data were obtained by ultrasonic inspection after dismantling the objects.

FPGA Based Acoustic Emission System

  • Autoři: Říha, L., prof. Ing. Radislav Šmíd, Ph.D., Kreidl, M.
  • Publikace: Measurement 2007 - Proceedings of 6th International Conference on Measurement. Bratislava: Institute of Measurement Science of the SAS, 2007. p. 275-278. ISBN 978-80-969672-0-9.
  • Rok: 2007
  • Pracoviště: Katedra měření
  • Anotace:
    This paper deals with a new FPGA (Field Programmable Gate Array) based measurement system for real time analysis of acoustic emission. Multichannel acoustic emissions systems usually process (measures) only a few simple parameters such as maximum amplitude, event duration, rise time, counts, counts to peak, etc. If higher accuracy of calculation is required, it is necessary to acquire and save more information from a measurement. The proposed system can preprocess measured signals and save them with lossless compression to the hard drive and compute the description parameters at the same time. Saved data can be used for the development of new acoustic emission signal processing methods.

Gearbox Housing Vibration Analysis Used for Localization of the Best Measuring Point for Gearwheel Behaviour Testing

  • Autoři: Dočekal, A., Kreidl, M., prof. Ing. Radislav Šmíd, Ph.D., Žák, P.
  • Publikace: Measurement 2007 - Proceedings of 6th International Conference on Measurement. Bratislava: Institute of Measurement Science of the SAS, 2007. pp. 346-349. ISBN 978-80-969672-0-9.
  • Rok: 2007
  • Pracoviště: Katedra měření
  • Anotace:
    This paper deals with signal processing for gearwheels vibration analysis. The main goal was localization of the best measuring point on the gearbox housing which could provide the highest sensitivity to gearwheels vibration. This work was done within the framework of experimental research which was concerned with testing and lifetime estimation of new designs of gearwheels.

New Interpolation Methods for Image-based Sub-pixel Displacement Measurement

  • Pracoviště: Katedra měření
  • Anotace:
    This paper deals with image-based displacement measurement. The correlation method of displacement measurement computes the cross-correlation function from two images captured by a CCD camera. The shift level is then determined by the position of the maximum value of the cross-correlation function. If the cross-correlation function is computed directly from two pictures, it is possible to determine the shift level only with resolution on whole pixels. If sub-pixel resolution is required, it is necessary to use interpolation. Interpolation of the input sequences requires high performance and expensive digital signal processors or field programmable gate arrays, therefore for a real-time application it is necessary to acquire the information about sub-pixel shift from a computed cross-correlation function. This paper describes two new real time methods which can obtain the information of the sub-pixel shift from the shape of the maximum of the cross-correlation function and its shape.

Noise and Signal Processing for EMAT NDT

  • Autoři: Kubínyi, M., prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: MDS - Měření, diagnostika, spolehlivost palubních soustav letadel - 7. mezinárodní vědecká konference. Brno: Univerzita obrany, Fakulta vojenských technologií, 2007. pp. 81-87. ISBN 978-80-7231-281-8.
  • Rok: 2007
  • Pracoviště: Katedra měření
  • Anotace:
    An ultrasound defectoscopy is worldwide used in the testing of materials and structures. Most transducers used for ultrasonic nondestructive testing (UNDT) are based on piezoelectric materials due to their ability to convert electric energy to mechanical energy and vice versa. This work is looking for ways to apply the non-contact ultrasound defectoscopy (EMAT - Electro-Magnetic Acoustic transducers) in the airplane inspection. The specific aeronautical conditions require high speed testing to reduce time when an airplane stays in a hangar for the inspection between its flights. The structural analyses are crucial in evaluation of airplane safety. Regarding to low EMAT conversion efficiency there are needed filtration methods of acquired signal. Choosing the most efficient signal processing method among others is based on EMAT noise expertise.

Přehled metod používaných pro filtraci ultrazvukových signálů

  • Autoři: Matz, V., Kreidl, M., prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: 37th International Conference Defektoskopie 2007. Brno: University of Technology, 2007, pp. 159-166. ISBN 978-80-214-3504-9.
  • Rok: 2007
  • Pracoviště: Katedra měření
  • Anotace:
    V příspěvku je uveden přehled nejpoužívanějších metod zpracování ultrazvukového signálu pro účinné potlačení šumu. Prezentováno je srovnání metod vlnkové transformace, Wienerovy filtrace a závěrem je diskutována metoda slepé separace signálu. Uvedené metody jsou analyzovány z hlediska potlačení šumu a nastavování vhodných parametrů.

Rotating Machine Vibration Analysis using Group of Adaptive Models Evolution

  • Autoři: Dočekal, A., Kreidl, M., prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: IWIM 2007 - International Workshop on Inductive Modelling. Praha: Czech Technical University in Prague, 2007, pp. 221-228. ISBN 978-80-01-03881-9.
  • Rok: 2007
  • Pracoviště: Katedra měření
  • Anotace:
    Modern rotating machinery often takes advantage of new designs of used gearwheels and rolling bearings. Recognition of frequencies of vibrations produced by an analyzed part of the machine is necessary for machine monitoring. Frequencies or bands produced by the analyzed part of the machine have to be estimated directly from the measured data in above mentioned cases. Group of Adaptive Models Evolution was used for this purpose for tapered roller bearing analysis and gear transmission vibration analysis. The paper contains comparison of usage GAME with another method which belongs to methods of feature selection.

Sensitivity Increasing of a Ultrasonic EMAT Materiology

  • Autoři: Kubínyi, M., prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: The third AIAA-Pegasus Student Conference. Napoli: Universita degli Studi di Napoli "Federico II", 2007,
  • Rok: 2007
  • Pracoviště: Katedra měření
  • Anotace:
    Ultrasound Electromagnetic Acoustic Transducer (EMAT) belongs into the group of Nondestruction Evaluation (NDE) methods and can be used in aerospace defect testing applications. Regarding to low EMAT conversion efficiency there are needed filtration ethods to apply on acquired signal. Different processing methods were analysed and appropriate methods were tested and proved on measured data. Various filtration methods results were compared and evaluated in Matlab software environment.

Signal Separation in Ultrasonic Non-Destructive Testing

  • Pracoviště: Katedra měření
  • Anotace:
    The sensitivity and resolution of ultrasonic non-destructive testing is limited by the backscattering and electronic noise level commonly contained in the acquired ultrasonic signals. This paper compares algorithms used for efficient noise reduction in ultrasonic signals in A-scan. Algorithms based on the discrete wavelet transform and the Wiener filter are considered. All proposed methods are evaluated on simulated and true ultrasonic signals.

Spectral Analysis of Tapered Roller Bearing Vibration Using Inductive Modeling

  • Autoři: Dočekal, A., Kreidl, M., prof. Ing. Radislav Šmíd, Ph.D., Říha, L.
  • Publikace: 14th International Congress on Sound and Vibration (ICSV14) - Proceedings. Cairns: International Institute of Acoustics and Vibration (IIAV), 2007. ISBN 978-0-7334-2516-5.
  • Rok: 2007
  • Pracoviště: Katedra měření
  • Anotace:
    This paper deals with a case of vibroacoustic testing of tapered roller bearings.The measured vibrations of the bearings were evaluated using methods of spectral analysis. Frequencies produced by the bearings and also important for the bearing condition analysis were found out using methods of Inductive modeling. Group Method of Data Handling and Group of Adaptive Models Evolution were used in particular.

Spectrum Enhancement of Laser Vibrometer Signals Using a New Speckle Noise Reduction Technique and Angular Resampling

  • Autoři: Vass, J., Randall, R.B., Cristalli, C., Torcianti, B., prof. Ing. Pavel Sovka, CSc., prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: 14th International Congress on Sound and Vibration (ICSV14) - Proceedings. Cairns: International Institute of Acoustics and Vibration (IIAV), 2007. ISBN 978-0-7334-2516-5.
  • Rok: 2007
  • Pracoviště: Katedra teorie obvodů, Katedra měření
  • Anotace:
    In this paper, a new method to enhance vibration signals measured by Laser Doppler Vibrometry (LDV) is proposed. The method has been applied to LDV signals measured on washing machines for the purpose of quality control in production lines.

Testing of an Airplane Structures with Non-contact Ultrasound Defectoscopy

  • Autoři: Kubínyi, M., prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: MOSATT 2007, Proceedings of the International Scientific Conference "Modern Safety Technologies in Transportation". Košice: Slovak Transport Society at the Slovak Academy of Sciences, 2007. pp. 160-164. ISBN 978-80-969760-2-7.
  • Rok: 2007
  • Pracoviště: Katedra měření
  • Anotace:
    An ultrasound defectoscopy is worldwide used in the testing of materials and structures. Classical piezoelectric transducers need coupling between the tested object and the probe. The specific aeronautical conditions require high speed testing to reduce time when an airplane stays in a hangar for the inspection between its flights. The structural analyses are crucial in evaluation of airplane safety. This work is looking for ways to apply the non-contact ultrasound defectoscopy (EMAT - Electro-Magnetic Acoustic transducers) in the airplane inspection. Dealing with signal processing may bring this type of structural analysis closer practical application. Due to the low signal to noise ratio of received signal the different methods must me explored. The goal of this paper is to compare performance of common filtering methods.

Ultrasonic Thickness Estimation Using Cross-Correlation

  • Autoři: Queirós, R., Matz, V., Girao, P.M., Serra, A.C., prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: Proceedings of the 6th Conference on Telecommunications. Lisboa: Instituto de Telecomunicaçoes - Lisboa, 2007, ISBN 978-989-8109-01-9.
  • Rok: 2007
  • Pracoviště: Katedra měření
  • Anotace:
    The paper presents methods for ultrasonic thickness estimation in ultrasonic testing. The methods based on cross-corelation and phase-shift were proposed. Both methods were verified on ultrasonic gauges and different kinds of materials.

Analysis of Rolling Bearings Vibration during Nondestructive Testing on Gearbox

  • Autoři: Dočekal, A., Kreidl, M., prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: ICSV13 - Vienna - The Thirteenth International Congress on Sound and Vibration - Proceedings. Wien: Technische Universität, 2006. ISBN 3-9501554-5-7.
  • Rok: 2006
  • Pracoviště: Katedra měření
  • Anotace:
    This paper describes a case of vibroacoustic testing of a gearbox. Especially conditions of a rolling bearing in the gearbox were analyzed and monitored. The aim of this work was recognition and classification of different types of rolling bearings faults. This work is focused on spectral analysis used for feature extraction. There were compared different ways of power spectral estimation during various load conditions and various revolution rates.

Application of GMDH Neural Networks for Evaluating of Tapered Roller Bearing Optimal Preload

  • Autoři: Dočekal, A., Kreidl, M., prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: Defektoskopie 2006. Praha: Česká společnost pro nedestruktivní testování, 2006, pp. 53-60. ISBN 80-214-3290-X.
  • Rok: 2006
  • Pracoviště: Katedra měření
  • Anotace:
    This paper describes a case of vibroacoustic testing of a tapered roller bearing. The main aim of this project was to evaluate an optimal value of the axial mechanical pre-load forcing on a tapered roller bearing. This objective was achieved via bearing vibration measurement. Spectral analysis was used to evaluate the tapered roller bearing vibration based on the known fact that bearing defects can be often detected and localized by their repetitive frequencies. The frequencies were estimated using the Group Method of Data Handling neural network.

Automatizace testování metodou vířivých proudů

  • Autoři: Kreidl, M., prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: Technická diagnostika. Senzory - metody - analýza signálu. Praha: BEN - technická literatura, 2006. p. 334-343. ISBN 80-7300-158-6.
  • Rok: 2006
  • Pracoviště: Katedra měření
  • Anotace:
    Kapitola se věnuje metodám zpracování signálu a klasifikace, umožňujícím automatizovat vyhodnocování při testování metodou vířivých proudů.

Classification of Ultrasonic Signals

  • Autoři: Matz, V., Kreidl, M., prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: International Journal of Materials & Product Technology. 2006, 27(3, 4), 145-155. ISSN 0268-1900.
  • Rok: 2006
  • Pracoviště: Katedra měření
  • Anotace:
    The paper describes the classification process of ultrasonic signals based on support vector machines classifier. Three types of ultrasonic signals are classified: signal with fault echo, signal without fault echo and signal in place of weld. First, the signals are de-noised by wavelet packet algorithm and the final signal is used for the feature extraction based on mathematical operations as mean, root mean square and absolute values. The best and successful classification is reached by using root mean square value feature extraction.

Comparison of De-noising Methods Used for EMAT Signals

  • Autoři: Štarman, S., Matz, V., Kreidl, M., prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: NDT Welding Bulletin. 2006, 2006(Special), 43-47. ISSN 1213-3825.
  • Rok: 2006
  • Pracoviště: Katedra měření
  • Anotace:
    Comparison of de-noising methods used for EMAT signál based on discrete wavelet transform and wavelet packets. The most efficient method based on wavelet packet was analyzed and the parameters for the improvement were searched.

Comparison of De-Noising Methods used for EMAT Signals

  • Autoři: Matz, V., Kreidl, M., prof. Ing. Radislav Šmíd, Ph.D., Štarman, S.
  • Publikace: ECNDT Berlin 2006 - 9th European Conference on NDT. Berlin: European Federation for Non-Destructive Testing, 2006, ISBN 3-931381-86-2.
  • Rok: 2006
  • Pracoviště: Katedra měření
  • Anotace:
    Comparison of de-noising methods used for EMAT signal based on discrete wavelet transform and wavelet packets. The most efficient method based on wavelet packet was analyzed and the parameters for the improvement were searched.

De-noising Methods Used for B-scan Filtering in Ultrasonic Testing

  • Autoři: Matz, V., Kreidl, M., prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: Defektoskopie 2006. Praha: Česká společnost pro nedestruktivní testování, 2006, pp. 151-158. ISBN 80-214-3290-X.
  • Rok: 2006
  • Pracoviště: Katedra měření
  • Anotace:
    Comparison of de-noising methods used for filtering B-scans in ultrasonic testing. The used filtering methods are based on wavelet transform, Wiener filter and basic mathematical methods as median and average values. The filtered B-scans were used for the 3D-volume visualization of flaws in tested material.

Flaw Shape Characterization in 3D Volume Visualization in Ultrasonic Testing

  • Autoři: Matz, V., prof. Ing. Radislav Šmíd, Ph.D., Kreidl, M., Keřka, J.
  • Publikace: 2006 IEEE International Symposium on Signal Processing and Information Technology. Vancouver: IEEE, 2006. p. 938-943. ISBN 978-0-7803-9753-8.
  • Rok: 2006
  • Pracoviště: Katedra měření
  • Anotace:
    Comparison of de-noising methods used for filtering of high dimensional pictures in B-scan ultrasonic signal. The used filtering methods are based on wavelet transform, Wiener filter and basic mathematical methods median and averaging. The filtered B-scans were used for the 3D-volume visualization of flaws in tested material.

Objective Assessment of Speech Distribution Quality by means of Unconventional PESQ Application - A Case Study

  • Pracoviště: Katedra měření
  • Anotace:
    The article describes non-traditional deployment of ITU-T P.862 (PESQ) algorithm for quality assessment of speech distribution. Subjective and objective results are presented and compared.

Reducing Speckle Noise in Vibration Signals Measured with Laser Doppler Vibrometry

  • Pracoviště: Katedra teorie obvodů, Katedra měření
  • Anotace:
    The article describes a new method of processing vibration data for detection of mechanical faults in electric motors on the production line.

Rozlišení zdrojů akustické emise založené na podobnosti v prostoru parametrů

  • Autoři: Říha, L., Bláha, J., prof. Ing. Radislav Šmíd, Ph.D., Kreidl, M.
  • Publikace: Defektoskopie 2006. Praha: Česká společnost pro nedestruktivní testování, 2006, pp. 209-215. ISBN 80-214-3290-X.
  • Rok: 2006
  • Pracoviště: Katedra měření
  • Anotace:
    Cílem příspěvku je popsat metodu vyvinutou pro rozlišení zdrojů akustické emise (AE) na základě podobnosti parametrů jejich jednotlivých emisních událostí. Metoda by měla pomoci určit zdroje AE související s porušením celistvosti materiálu konstrukcí dlouhodobě monitorovaných systémy AE za provozu. Po provedení standardních postupů hodnocení dat AE naměřených při takovém monitorování bývá nalezeno množství shluků AE, u kterých je třeba rozhodnout o původu jejich emisní aktivity a o jejich závažnosti vzhledem k celistvosti materiálu konstrukce. Navržená metoda využívá charakteristické chování zdrojů AE generovaných růstem defektu typu trhlina v materiálu konstrukce pro rozlišení původu emisní aktivity shluků AE, a to i u systémů AE pracujících pouze s parametry jednotlivých emisních událostí.

Signal Preprocessing Methods for Automated Analysis of Eddy Current Signatures

  • Autoři: Dočekal, A., Kreidl, M., prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: ECNDT Berlin 2006 - 9th European Conference on NDT. Berlin: European Federation for Non-Destructive Testing, 2006, ISBN 3-931381-86-2.
  • Rok: 2006
  • Pracoviště: Katedra měření
  • Anotace:
    In this contribution, a novel method for the automatic evaluation of flaws during a manual Eddy Current (EC) inspection procedure is presented. Algorithms were especially designed with respect to characteristics typical for a hand-held EC testing procedure. In manual scanning, a signal related to impedance change in the complex plane is affected by large and unpredictable variations of scanning speed and alternations of the probe position. The detection of flaws in the object tested is also affected by the imperfections of device electronics, mainly of null drift. The lift-off effect of the inspection probe is required for consideration as well.

System for 3D Visualization of Flaws for Eddy Current Inspection

  • Pracoviště: Katedra měření
  • Anotace:
    This paper deals visualization method for eddy current inspection of cracks. This method is based on Fourier transform. The 3D visualization of flaws enables determination of flaws position and estimation of the size (length) and the angle to surface.

Systém pro 3D vizualizaci trhlin v defektoskopii vířivými proudy

  • Pracoviště: Katedra měření
  • Anotace:
    V článku je uvedena metoda vizualizace trhlin metodou vířivých proudů. Metoda je založena na Fourierově transformaci. 3D zobrazení výsledku testu umožňuje stanovení pozic nalezených vad a odhad jejich velikostí a sklonu k povrchu.

Technická diagnostika. Senzory - metody - analýza signálu

  • Pracoviště: Katedra měření
  • Anotace:
    Senzory neelektrických veličin - 4. díl Tato kniha obsahuje principy diagnostických metod. Všechny uvedené metody jsou doplněny přehledem vhodných senzorů. Samostatnou část knihy tvoří zpracování diagnostických signálů. Jsou uvedeny standardní a pokročilé metody analýzy signálu.

Analysis and Filtering of Ultrasonic Signal

  • Autoři: Matz, V., Kreidl, M., prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: Proceedings of Workshop 2005 - Part A,B. Praha: České vysoké učení technické v Praze, 2005, pp. 384-385. ISBN 80-01-03201-9.
  • Rok: 2005
  • Pracoviště: Katedra měření
  • Anotace:
    Description of method used for filtering of ultrasonic signal based on the wavelet transform. For filtering methods discrete wavelet transform and wavelet packets were used.

Automated Classification of Eddy Current Signatures during Manual Inspection

  • DOI: 10.1016/j.ndteint.2004.12.004
  • Odkaz: https://doi.org/10.1016/j.ndteint.2004.12.004
  • Pracoviště: Katedra měření
  • Anotace:
    This article presents a novel method for automatic evaluation of flaws during a manual eddy current (EC) inspection procedure. The paper introduces a robust EC signal normalization method using non-linear filtration based on evaluation of the distance between consecutive samples in the complex plane and median based tracking of the EC signature. The classification was performed using six different methods.

Classification of Ultrasonic Signals

  • Autoři: Matz, V., Kreidl, M., prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: Application of Contemporary Non-Destructive Testing in Engineering - Conference Proceedings. Ljubljana: The Slovenian Society for Non-Destructive Testing, 2005. p. 27-33.
  • Rok: 2005
  • Pracoviště: Katedra měření
  • Anotace:
    This work is focused on classification of ultrasonic signals. For classification three different types of signals were used: Clear signal, signal with fault echo and signal from the center of the weld. These signals are classified with method based on support vector machines, with pre-processing method for filtering of ultrasonic signals based on wavelet packets.

Classification of Ultrasonic Signals

  • Autoři: Matz, V., Kreidl, M., prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: Application of Contemporary Non-Destructive Testing in Engineering - Conference Proceedings. Ljubljana: The Slovenian Society for Non-Destructive Testing, 2005. pp. 27-33. ISBN 961-90610-5-5.
  • Rok: 2005
  • Pracoviště: Katedra měření
  • Anotace:
    In ultrasonic defectoscopy it is very difficult to detect flaw in materials with coarse-grain structure. The ultrasonic signals measured on these materials contain echoes which are very similar to fault echo. These echoes arise from grains which are contained in material. For detection of flaw various methods for suppressing of echoes from grains have to be used. In this work we used the method for filtering of ultrasonic signal based on discrete wavelet transform. For classification of ultrasonic signals in A-scan we used pattern recognition method called support vector machines. In this study we classify signals with fault echo, echo from weld and back-wall echo. Ultrasonic signals were measured on material used for constructing airplane engines. The experimental results indicate the performance of the proposed approach.

Condition Indicators for Gearbox Condition Monitoring Systems

  • Pracoviště: Katedra měření
  • Anotace:
    Frequently used condition indicators (CIs) are described in this paper. The ability of a selected condition indicator to describe the degree of gearing wear was tested using vibration signals acquired during durability testing of manual transmission with helical gears.

Detection and Visualization of Flaws in Ultrasonic Defectoscopy

  • Autoři: Matz, V., Kreidl, M., prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: 10th IMEKO TC10 - International Conference on Technical Diagnostics. Budapest: Hungarian Academy of Sciences, 2005. p. 121-125. ISBN 963-86586-4-9.
  • Rok: 2005
  • Pracoviště: Katedra měření
  • Anotace:
    This work is focused on visualization of flaws in ultrasonic defectoscopy. For filtering the method based on discrete wavelet transform was used with the following 3D volume visualization. For compactnes of exact shape of flaw the method based on mathematical morphology was also used. For the detection of flaw the neural network with backpropagation algorithms was proposed. By proposed method it is possible to create exact shape of flaw in 3D space.

Measurement of Acoustic Emission and Vibration

  • Autoři: Batěk, M., Dočekal, A., Kreidl, M., prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: Defektoskopie 2005. Sborník příspěvků z 35. mezinárodní konference. Brno: Czech Society for Nondestructive Testing, 2005, pp. 11-15. ISBN 80-214-3053-2.
  • Rok: 2005
  • Pracoviště: Katedra měření
  • Anotace:
    This paper describes a system for simultaneous recording of acoustic emission and vibration signals from rotational mechanisms.

Methodology for Voice Transmission Measurement Systems Verification

  • Pracoviště: Katedra měření
  • Anotace:
    Set of tests designed for VTQOS system verification is proposed, including examples and practical reasons for this selection.

System for Simultaneous Measurement of Acoustic Emission and Vibration

  • Autoři: Dočekal, A., Kreidl, M., prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: Defektoskopie 2005. Sborník příspěvků z 35. mezinárodní konference. Brno: Czech Society for Nondestructive Testing, 2005, pp. 11-15. ISBN 80-214-3053-2.
  • Rok: 2005
  • Pracoviště: Katedra měření
  • Anotace:
    A solution of the synchronization of two mutually separated instruments is proposed in this paper. The system is able to measure continuous acoustic emission and vibration at the same time. The created system is used for evaluation of the correlation between vibration and continuous acoustic emission that are measured on a monitored object.

System for Visualization of Flaws in Ultrasonic Defectoscopy

  • Autoři: Matz, V., Kreidl, M., prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: Defektoskopie 2005. Sborník příspěvků z 35. mezinárodní konference. Brno: Czech Society for Nondestructive Testing, 2005, pp. 143-150. ISBN 80-214-3053-2.
  • Rok: 2005
  • Pracoviště: Katedra měření
  • Anotace:
    This work is focused on visualization of flaws in ultrasonic defectoscopy. For filtering the method based on discrete wavelet transform called wavelet packets was used with the following 3D volume visualization. For compactness of exact shape of flaw the method based on statistical recognition called Support vector machines was proposed. By proposed methods it is possible to create exact shape of flaw in 3D space.

Wavelet Transform Based Methods for Biomedical Shape Description

  • Autoři: prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: Proceedings of Workshop 2005 - Part A,B. Praha: České vysoké učení technické v Praze, 2005. pp. 768-769. ISBN 80-01-03201-9.
  • Rok: 2005
  • Pracoviště: Katedra měření
  • Anotace:
    The paper summarizes the results of the project "Characterization of morphological reactions of organ cultures by means of wavelet transform based correlation and cepstral analysis".

A Dependence between Average Call Duration and Voice Transmission Quality: Measurement and Applications

Comparison of Methods Based on Discrete Wavelet Transform Used for Filtering of Ultrasonic Signal

  • Autoři: Matz, V., Kreidl, M., prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: Defektoskopie 2004. Praha: Česká společnost pro nedestruktivní testování, 2004, pp. 115-120. ISBN 80-214-2749-3.
  • Rok: 2004
  • Pracoviště: Katedra měření
  • Anotace:
    In ultrasonic testing it is very important to recognize fault echoes buried in noisy signal. The fault echo characterizes flaw in material. To differentiate the fault echo from the noise, a suitable filtering method has to be used. This can be accomplished using discrete wavelet transform (DWT), which is used for enhancement signal-to-noise ratio. In this study for comparison of quality of filtering, DWT and wavelet packets (WP) are used. Additional computer simulations of the proposed algorithms are presented.

Gearbox Diagnostics Using Advanced Methods of Signal Processing

  • Autoři: Večeř, P., Kreidl, M., prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: Workshop 2004. Praha: České vysoké učení technické v Praze, 2004. pp. 296-297. ISBN 80-01-02945-X.
  • Rok: 2004

Multi-scale Methods for Biomedical Shape Evaluation

  • Pracoviště: Katedra měření
  • Anotace:
    The aim of the described project is to develop new description methods of growth and morphological parameters of dorsal root ganglia based on wavelet packets, wavelet autocorrelation, wavelet power spectrum, and wavelet cepstrum from sequences of microscopic images. The paper summarizes the obtained results.

Processing Power Optimisation for PESQ

  • Pracoviště: Katedra měření
  • Anotace:
    This article identifies several areas of possible reduction of processing power requirements of the PESQ algorithm (ITU-T P.862). As a result, PDA-based implementation of PESQ-based speech transmission quality measurement system for GSM networks is presented and required computational times are discussed.

Signal-to-Noise Ratio Improvement Based on the Discrete Wavelet Transform in Ultrasonic Defectoscopy

  • Pracoviště: Katedra měření
  • Anotace:
    A new method for filtering of ultrasonic signal using discrete wavelet transform is presented. The method is based on the thresholding of wavelet coefficients using local threshold related to the standard deviation of the decomposed signal. The proposed approach was tested on coarse grain materials used for airplane engines and on simulated signals with artificial noise.

Using Adaptive-Network-based Fuzzy Inference System for the Manual Transmission Diagnostics

  • Autoři: Večeř, P., Kreidl, M., prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: Nové smery v spracovaní signálov VII. Liptovský Mikuláš: Vojenská akadémia, 2004, pp. 46-49. ISBN 80-8040-232-9.
  • Rok: 2004
  • Pracoviště: Katedra měření
  • Anotace:
    This paper presents the application of advanced neural network techniques in gearbox diagnostics. A system is described which classify tested gearbox according to amplitude features of their vibration signal. A classifier is based on Adaptive-Network-based Fuzzy inference system (ANFIS).

Zkoumání morfologických reakcí spinálních ganglií metodami 3D mikroskopie

  • Pracoviště: Katedra měření
  • Anotace:
    Příspěvek popisuje metody získávání třídimenzionálních obrázků objektů ze dvoudimenzionálních obrazů snímaných optickým mikroskopem. Výsledek číslicového zpracování obrazových signálů je kompletní 3D ostrý obrázek objektu získaný jako kombinace zaostřených částí jednotlivých obrazů. Metody jsou aplikovány pro výzkum morfologických reakcí spinálních ganglií na neurotoxické látky.

Application of the Self-Organizing Map to Manual Automotive Transmission Diagnostics

Child Listeners as the Test Subject - Comparison with Adults and P.862

Data Acquisition and Pre-processing for Vehicle Gearbox Diagnostics

  • Autoři: Večeř, P., prof. Ing. Radislav Šmíd, Ph.D., Kreidl, M.
  • Publikace: Proceedings of Workshop 2003. Praha: České vysoké učení technické v Praze, 2003, pp. 264-265. ISBN 80-01-02708-2.
  • Rok: 2003

Intrusive Speech Transmission Quality Measurements for Low Bit-Rate Coded Audio Signals

Planar Shape Description by Means of Wavelet Transform

  • Autoři: prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: Proceedings of Workshop 2003. Praha: České vysoké učení technické v Praze, 2003, pp. 904-905. ISBN 80-01-02708-2.
  • Rok: 2003

Planar Shape Description Using Wavelet Packets for Biomedical Applications

Ultrasonic Signal Filtering

  • Autoři: prof. Ing. Radislav Šmíd, Ph.D., Matz, V., Kreidl, M.
  • Publikace: Defektoskopie 2003. Praha: Česká společnost pro nedestruktivní testování, 2003. p. 259-262. ISBN 80-214-2475-3.
  • Rok: 2003

Voice Transmission Quality Measurement Based on Wavelet Transformation

Voice Transmission Quality Measurement Based on Wavelet Transformation

Wavelet Correlation for Biomedical Shape Evaluation

  • Autoři: prof. Ing. Radislav Šmíd, Ph.D., Ďaďo, S.
  • Publikace: Measurement 2003 - Proceedings of the 4th International Conference on Measurement. Bratislava: Slovak Academy of Sciences, Institute of Measurement Science, 2003, pp. 256-259. ISBN 80-967402-6-1.
  • Rok: 2003

Wavelet Correlation for Biomedical Shape Evaluation

Wavelet Transform in Voice Transmission Quality Measurements

A Novel Intrusive Voice Transmission Quality Test System for Mobile Networks

Detection of Flaws around Aircraft Fasteners

  • Autoři: prof. Ing. Radislav Šmíd, Ph.D., Kreidl, M., Houfek, P.
  • Publikace: Proceedings of Workshop 2002. Praha: České vysoké učení technické v Praze, 2002, pp. 500-501. ISBN 80-01-02511-X.
  • Rok: 2002

High Resolution ADC Testing by Means of Standard Test Methods

Intrusive Speech Quality Measurements in Czech Environment

Parametrization of Eddy Current Signatures by Means of Discrete Wavelet Transform

  • Autoři: prof. Ing. Radislav Šmíd, Ph.D., Kreidl, M.
  • Publikace: Defectoscopy 2002. Liberec: Czech Society for Nondestructive Testing, 2002, pp. 297-301. ISBN 80-214-2247-5.
  • Rok: 2002

Planar Shape Descriptor Based on Wavelet Packets

  • Autoři: prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: IFMBE Proceedings. Wien: Technische Universität, 2002. pp. 948-949. ISSN 1680-0737. ISBN 3-901351-62-0.
  • Rok: 2002

Standard sériového rozhraní pro měřicí přístroje

Voice Transmission Quality - On-line Workshop

Voice Transmission Quality Measurement

Wavelet Transform Based Correlation and Cepstral Analysis

  • Autoři: prof. Ing. Radislav Šmíd, Ph.D., Ďaďo, S., Rohovský, P.
  • Publikace: Proceedings of Workshop 2002. Praha: České vysoké učení technické v Praze, 2002, pp. 904-905. ISBN 80-01-02511-X.
  • Rok: 2002

Wavelet transformace pro popis planárního tvaru

  • Autoři: prof. Ing. Radislav Šmíd, Ph.D., Ďaďo, S.
  • Publikace: Nové smery v spracovaní signálov VI. Liptovský Mikuláš: Vojenská akadémia, 2002. pp. 257-260. ISBN 80-8040-180-2.
  • Rok: 2002

Advanced Measurements in Mobile Networks

Biomedical Shape Measurement for Neurotoxicity Testing

  • Autoři: Ďaďo, S., Mandys, V., prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: Measurement 2001. Bratislava: Institute of Measurement Science of the SAS, 2001. pp. 309-312. ISBN 80-967402-5-3.
  • Rok: 2001

Biomedical Shape Measurement for Neurotoxicity Testing

Complex Measurement Laboratory Exercising

Hodnocení hlasových přenosů v telekomunikačních sítích

How to Exercise Complex Measurements

How to Exercise Complex Measurements

Measurement of Voice Transmission Quality in Mobile Networks

Odhad rychlosti pohybu objektů v obraze

  • Autoři: Ďaďo, S., prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: Trendy lesníckej, drevárskej a environmentálnej techniky a jej aplikácie vo výrobnom procese. Zvolen: Technická univerzita vo Zvolene, 2001, pp. 65-69. ISBN 80-228-1058-4.
  • Rok: 2001

Přenos hlasu v moderních telekomunikačních sítích - měření kvality

Sensors Linearity Improvement by Means of Dithering: Feasibility and Limits

Sensors Linearity Improvement by Means of Dithering: Feasibility and Limits

Videometric Analysis of Morphological Changes for Neurotoxicity Testing

  • Autoři: prof. Ing. Radislav Šmíd, Ph.D., Ďaďo, S., Mandys, V.
  • Publikace: Proceedings of Workshop 2001. Praha: České vysoké učení technické v Praze, 2001, pp. 780-781. ISBN 80-01-02335-4.
  • Rok: 2001

Výukový WWW systém pro modulární kursy moderních senzorů

WWW System for Modular Courses on Modern Sensors

Analýza signálu pomocí vlnkové transformace

Application of Videometry for Neurotoxicity Testing

  • Autoři: prof. Ing. Radislav Šmíd, Ph.D., Ďaďo, S., Mandys, V.
  • Publikace: Proceedings of Workshop 2000. Praha: České vysoké učení technické v Praze, 2000. pp. 517. ISBN 80-01-02229-3.
  • Rok: 2000

Interferogram Processing for Absolute Length Measurement Using Multiple-wavelength Phase-stepping Interferometry

  • Autoři: prof. Ing. Radislav Šmíd, Ph.D., Šmíd, M.
  • Publikace: Proceedings of Workshop 2000. Praha: České vysoké učení technické v Praze, 2000. pp. 218. ISBN 80-01-02229-3.
  • Rok: 2000

Mobile Networks: Advanced Measurements and Special Applications

Použití vlnkové korelace pro charakterizaci biomedicínských tvarů

  • Autoři: Ďaďo, S., prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: Nové směry ve zpracování signálů 5. Liptovský Mikuláš: Vojenská akadémia, 2000. pp. 342-349. ISBN 80-8040-125-X.
  • Rok: 2000

Statistické zpracování výsledků pozorování s využitím výpočetního systému MATLAB

  • Autoři: Boháček, J., prof. Ing. Radislav Šmíd, Ph.D., Pfeifer, P.
  • Publikace: Matlab 2000 - Sborník příspěvků 8. ročníku konference. Praha: Vysoká škola chemicko-technologická, 2000, pp. 55-60. ISBN 80-7080-401-7.
  • Rok: 2000

Various Scale Errors in Dithered Quantizers. Visualisation and Reduction

Využití protokolu WAP a jazyka WML v měřicí a řídicí technice

A New Time-Saving Method for ADC Testing

Application of Sensor Fusion Principle for Positioning System Improvement

Biological Shape Description Using Multiscale Approach

Chirp Based Method for ADC Testing: Simulation and Evaluation

Image Based Measurement for Neurotoxicity Testing

  • Autoři: prof. Ing. Radislav Šmíd, Ph.D., Šmída, O.
  • Publikace: Poster 1999. Praha: České vysoké učení technické v Praze, Fakulta elektrotechnická, 1999, pp. 34-35.
  • Rok: 1999

Měření vektorů rychlosti pomocí obrazové informace

  • Autoři: prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: Snímače - Senzory - Aplikace. Ostrava: Ostravská univerzita, 1999, pp. 23-26. ISBN 80-7042-785-X.
  • Rok: 1999

Trojrozměrné měření a popis tvaru v mikroskopii biologických vzorků

  • Pracoviště: Katedra měření
  • Anotace:
    Článek přibližuje vybrané metody pro trojrozměrné (dále jen 3D) mikroskopické snímání biologických objektů a popis jejich tvaru pro účely měření a hodnocení tvarových změn.

Využití MATLABu ve výuce Zpracování signálů na katedře měření ČVUT FEL

  • Pracoviště: Katedra měření
  • Anotace:
    Na katedře měření FEL ČVUT se v rámci cvičení předmětů Zpracování signálů a obrazů a Vybrané metody digitalizace signálu používá program MATLAB s toolboxy Signal Processing a Wavelets, které obsahují sadu funkcí zabývajících se analýzou a syntézou signálů. Byla vytvořena interaktivní rozhraní např. pro základní seznámení s rychlou Fourierovou transformací, návrh číslicových filtrů typu FIR a IIR z průběhu jejich přenosové charakteristiky, demonstrace výpočtů vzájemné korelační a autokorelační funkce, atd.

Charakterizace tvaru objektů v obraze pomocí spojité vlnkové transformace

  • Autoři: Ďaďo, S., prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: Nové smery v spracovaní signálov IV. Liptovský Mikuláš: Vojenská akadémia, 1998, pp. 3-6. ISBN 80-8040-071-7.
  • Rok: 1998

Linearization of Transfer Characteristics of A/D Converters Using Dithering

  • Pracoviště: Katedra měření
  • Anotace:
    Linearizace převodních charakteristik A/D převodníků přídavným signálem

Praktické použití Internetu jako média pro virtuální konferenci

  • Pracoviště: Katedra měření
  • Anotace:
    Virtuální konference pořádané pomocí Internetu představují atraktivní a efektivní metodu pro výměnu vědeckých informací. Její základní výhodou je rychlost, úspora nákladů na cestovné a ubytování účastníků. Je však nutné řešit problémy s uznáváním příspěvků vědeckou komunitou a s nedostatkem interpersonálních kontaktů.

Pros and Cons of On-line Workshop Held Using Internet Technology

Shape Characterization for Neurotoxicity Testing

  • Autoři: prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: Poster 1998. Praha: České vysoké učení technické v Praze, Fakulta elektrotechnická, 1998, pp. 32-33.
  • Rok: 1998

Virtuální internetová konference Dithering in Measurement: Theory and Applications

Visualisation and Reduction of Various Scale Errors in Dithered Quantizers

Visualisation of Errors of Dithered Quantizer Using Continuous Wavelet Transform

Measuring of Area and Shape of Organotypic Cultures for Neurotoxicity Testing

  • Autoři: Hampl, K., Nekola, M., prof. Ing. Radislav Šmíd, Ph.D.,
  • Publikace: Poster 1997. Praha: České vysoké učení technické v Praze, Fakulta elektrotechnická, 1997, pp. 114-115.
  • Rok: 1997

Morphometry of Organotypic Cultures for Neurotoxicity Testing

  • Pracoviště: Katedra měření
  • Anotace:
    Morfometrické metody určování neurotoxicity pomocí orgánových kultur

Měření průtoku pevných částic

Za stránku zodpovídá: Ing. Mgr. Radovan Suk