Impulse noise

About: Impulse noise is a research topic. Over the lifetime, 4816 publications have been published within this topic receiving 63970 citations.

On the Potential Advantage of a Smearing-Desmearing Filter Technique in Overcoming Impulse-Noise Problems in Data Systems

Abstract: It has long been recognized that impulse noises or even very short duration line interruptions are the most vicious form of interference affecting data communications over wire lines. These noises, while annoying, are not catastrophic in voice communications because of the inherent redundancy in speech sounds. If a degree of apparent redundancy can be inserted into a data stream, the serious degradation caused by these noises can be materially reduced. Data signals which require a sizable bandwidth can be transmitted by modifying the real time placement of their frequency components (smearing) before transmission through a channel corrupted by impulse noises. A reversal of the time-vsenergy frequency modification before detection (desmear) reconstructs the data signal but "smears" the impulse or line interruption into a time-energy distribution form considerable different from that of the signal.

Measurement and analysis of impulsive noise on in-vehicle power lines

Abstract: In-vehicle signal transmission requires dedicated communication cables such as twisted metal wires and optical fiber cables, which increase the weight and the volume of wiring harnesses in vehicles. Furthermore, the number of electronic control units (ECUs) and the other electronic devices in vehicles is increasing. As a result, in-vehicle networks are becoming more and more complex and unstable. In-vehicle power line communication (PLC) system has been proposed to carry out signal transmissions between ECUs via in-vehicle power lines. The in-vehicle PLC system simplifies in-vehicle networks and reduces the weight and the volume of wiring harnesses. To design communication systems, we analyze communication environments which are mainly characterized by propagation channels and additive noise. In this paper, the measurement and the analysis of frequency responses for in-vehicle power lines are presented to analyze the propagation channels. Thus we observe frequency-selective fading channels which have several notches in the frequency domain because of reflection of signals at impedance mismatching points.We also analyze the noise and the interference in order to design reliable communication systems. For this purpose, the measurement and analysis of the noise on in-vehicle power lines are presented. A lot of bursty impulsive noises are observed while actuators in vehicles are active. A time-frequency analysis is applied to the observed noise and we show time-varying frequency spectra of the observed noise. Finally, we discuss in-vehicle PLC schemes which are suitable for signal transmissions.

Robustifying Vector Median Filter

Abstract: This paper describes two methods for impulse noise reduction in colour images that outperform the vector median filter from the noise reduction capability point of view Both methods work by determining first the vector median in a given filtering window Then, the use of complimentary information from componentwise analysis allows to build robust outputs from more reliable components The correlation among the colour channels is taken into account in the processing and, as a result, a more robust filter able to process colour images without introducing colour artifacts is obtained Experimental results show that the images filtered with the proposed method contain less noisy pixels than those obtained through the vector median filter Objective measures demonstrate the goodness of the achieved improvement

Probabilistic decision based filter to remove impulse noise using patch else trimmed median

Abstract: A new probabilistic decision based filter (PDBF) is presented to remove salt and pepper impulse noise in highly corrupted images. The filter employs two types of estimation techniques for denoising namely trimmed median (TM) and patch else trimmed median (PETM) which is our main contribution in this paper. Depending upon the estimated noise density, the filter utilizes either TM or PETM and hence enhanced outcome of denoising. Simulation results prove that the PDBF has outperformed recently proposed state-of-the-art filters in terms of peak signal to noise ratio (PSNR), structural similarity index (SSIM), image enhancement factor (IEF), mean absolute error (MAE) and visual representation at the noise densities (ND) as high as 95%.

Robust detection of ultra-wideband signals in non-Gaussian noise

Abstract: A robust receiver is proposed for time-hopping pulse-position-modulation impulse radio systems transmitting over frequency-selective ultra-wideband channels, which aims to remove large-amplitude outliers that occur due to impulsive noise. The proposed system contains a rake structure for collecting the signal energy, which is dispersed over a large number of paths as a result of the wide channel bandwidth. Before the paths are merged via maximal ratio combining, they are passed through nonlinearities to trim the outlier noise components. The robust receiver so designed is shown to outperform the conventional linear rake receiver that consists of only matched filters at its fingers.