The Experts below are selected from a list of 282 Experts worldwide ranked by ideXlab platform
Richard H Middleton - One of the best experts on this subject based on the ideXlab platform.
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output feedback stabilisation over bandwidth limited signal to noise Ratio constrained communication channels
American Control Conference, 2006Co-Authors: Alejandro J Rojas, Julio H Braslavsky, Richard H MiddletonAbstract:Stabilisability of an open loop unstable plant is studied under the presence of a bandwidth limited additive coloured noise communication channel with constrained signal to noise Ratio. The problem is addressed through the use of an LTI filter explicitly modelling the bandwidth limitation, and another LTI filter to model the additive coloured noise. Results in this paper show that a bandwidth limitation increases the minimum value of signal to noise Ratio required for stabilisability, in comparison to the infinite bandwidth, white noise case. Examples are used to illustrate the results in the continuous and discrete framework.
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feedback stabilization over signal to noise Ratio constrained channels
American Control Conference, 2004Co-Authors: Julio H Braslavsky, Richard H Middleton, J S FreudenbergAbstract:There has recently been significant interest in feedback stabilization problems over communication channels, including several with bit rate limited feedback. Motivated by considering one source of such bit rate limits, we study the problem of stabilization over a Signal-to-Noise Ratio (SNR) constrained channel. We discuss both continuous and discrete time cases, and show that for either state feedback, or for output feedback delay-free, minimum phase plants, there are limitations on the ability to stabilize an unstable plant over an SNR constrained channel. These limitations in fact match precisely those that might have been inferred by considering the associated ideal Shannon capacity bit rate over the same channel.
Marcel Kreidl - One of the best experts on this subject based on the ideXlab platform.
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signal to noise Ratio enhancement based on wavelet filtering in ultrasonic testing
Ultrasonics, 2009Co-Authors: Vaclav Matz, Radislav Smid, Stanislav Starman, Marcel KreidlAbstract: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.
Jari Korhonen - One of the best experts on this subject based on the ideXlab platform.
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peak signal to noise Ratio revisited is simple beautiful
Quality of Multimedia Experience, 2012Co-Authors: Jari KorhonenAbstract:Heavy criticism has been directed against using peak Signal-to-Noise Ratio (PSNR) as a full reference quality metric for digitally processed images and video, since many studies have shown a weak correlation between subjective quality scores and the respective PSNR values. In this paper, we show that the low performance of PSNR is often related to a content dependent systematic shift of PSNR values. In scenarios with fixed content and distortion types that are typical for visual communications applications, PSNR may perform closely as well, or in some cases even better than the more complex objective quality models known from the literature. Therefore, the use of PSNR may be justified for comparative quality assessment with fixed content.
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QoMEX - Peak Signal-to-Noise Ratio revisited: Is simple beautiful?
2012 Fourth International Workshop on Quality of Multimedia Experience, 2012Co-Authors: Jari KorhonenAbstract:Heavy criticism has been directed against using peak Signal-to-Noise Ratio (PSNR) as a full reference quality metric for digitally processed images and video, since many studies have shown a weak correlation between subjective quality scores and the respective PSNR values. In this paper, we show that the low performance of PSNR is often related to a content dependent systematic shift of PSNR values. In scenarios with fixed content and distortion types that are typical for visual communications applications, PSNR may perform closely as well, or in some cases even better than the more complex objective quality models known from the literature. Therefore, the use of PSNR may be justified for comparative quality assessment with fixed content.
Julio H Braslavsky - One of the best experts on this subject based on the ideXlab platform.
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output feedback stabilisation over bandwidth limited signal to noise Ratio constrained communication channels
American Control Conference, 2006Co-Authors: Alejandro J Rojas, Julio H Braslavsky, Richard H MiddletonAbstract:Stabilisability of an open loop unstable plant is studied under the presence of a bandwidth limited additive coloured noise communication channel with constrained signal to noise Ratio. The problem is addressed through the use of an LTI filter explicitly modelling the bandwidth limitation, and another LTI filter to model the additive coloured noise. Results in this paper show that a bandwidth limitation increases the minimum value of signal to noise Ratio required for stabilisability, in comparison to the infinite bandwidth, white noise case. Examples are used to illustrate the results in the continuous and discrete framework.
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feedback stabilization over signal to noise Ratio constrained channels
American Control Conference, 2004Co-Authors: Julio H Braslavsky, Richard H Middleton, J S FreudenbergAbstract:There has recently been significant interest in feedback stabilization problems over communication channels, including several with bit rate limited feedback. Motivated by considering one source of such bit rate limits, we study the problem of stabilization over a Signal-to-Noise Ratio (SNR) constrained channel. We discuss both continuous and discrete time cases, and show that for either state feedback, or for output feedback delay-free, minimum phase plants, there are limitations on the ability to stabilize an unstable plant over an SNR constrained channel. These limitations in fact match precisely those that might have been inferred by considering the associated ideal Shannon capacity bit rate over the same channel.
Vaclav Matz - One of the best experts on this subject based on the ideXlab platform.
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signal to noise Ratio enhancement based on wavelet filtering in ultrasonic testing
Ultrasonics, 2009Co-Authors: Vaclav Matz, Radislav Smid, Stanislav Starman, Marcel KreidlAbstract: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.
