Impulse noise

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

Fundamental Performance Limits for PLC Systems Impaired by Impulse Noise

Abstract: In this paper, we provide insights on the ultimate performance limits, in terms of achievable information rate, for power line communicationn (PLC) systems impaired by impulse noise. In particular, we analyze single carrier (SC) and multiple carrier (MC) transmission systems employing quadrature amplitude modulation (QAM) formats. In order to compute the information rates of standard MC systems, we introduce a theoretically equivalent channel model which allows the exact computation of the information rate. This simplified channel model will be referred to as interleaved MC channel model. We show that the use of MC schemes leads to an unavoidable loss with respect to SC schemes. In order to validate our theoretical results, we analyze the bit error rate (BER) performance of SC and MC schemes through Monte Carlo simulations. Several trellis-coded modulation (TCM) and low-density parity-check (LDPC)-coded schemes are considered.

Impulse burst position detection and channel estimation schemes for OFDM systems

Abstract: A new method for compensating the effects of impulse noise in OFDM systems has been presented by Rinne, Henriksson and Hazmi (see Proc. 7th International OFDM Workshop, Hamburg. Germany, p.183-187, Sept. 2002). It is shown that in the AWGN case, the method can effectively cancel the impulse noise. However in the time-frequency selective channel further measures are needed. The purpose of this paper is to present an enhanced channel estimation scheme for the standard method to overcome its sensitivity to the time frequency selective channel estimates. The scheme uses the impulse free pilots to estimate the corrupted ones. Three different alternatives are discussed. Their performances in mean squared error (MSE) versus Doppler frequency are studied analytically. Bit error rate ratio (BER) simulations results are given, in the cases of SFN hilly terrain static and mobile channels. Additionally, results on simple practical impulse burst position detection method are also presented.

Guidelines for Preparing Environmental Impact Statements on Noise

Abstract: : Guidelines are proposed for the uniform description and assessment of the various noise environments potentially requiring an Environmental Impact Statement for Noise. In addition to general, audible noise environments, the report covers separately high-energy impulse noise, special noises such as ultrasound and infrasound, and the environmental impact of structure-borne vibration. Whenever feasible and practical, a single-number noise impact characterization is recommended, based on the new concept of level-weighted population: i.e., the summation over the total population of the product of each residential person times a weighting factor that varies with yearly day-night average sound level outside the residence of that person. A sound-level weighting function for general impact and environmental degradation analysis is proposed, based on the average annoyance response observed in community response studies; this weighting function is supplemented by an additional weighting function at higher noise environments to quantify the potential of noise-induced hearing loss and general health effects. The evaluation of the environmental impact of vibration is derived from existing or proposed ISO standards. The report explains and justifies the procedures selected and gives examples of their application.

An efficient method for impulse noise reduction from images using fuzzy cellular automata

Abstract: Impulse noise reduction from corrupted images plays an important role in image processing. This problem will also affect on image segmentation, object detection, edge detection, compression, etc. Generally, median filters or nonlinear filters have been used for noise reduction but these methods will destroy the natural texture and important information in the image like the edges. In this paper, to eliminate impulse noises from noisy images, we used a hybrid method based on cellular automata (CA) and fuzzy logic called Fuzzy Cellular Automata (FCA) in two steps. In the first step, based on statistical information, noisy pixels are detected by CA; then using this information, the noisy pixel will change by FCA. Regularly, CA is used for systems with simple components where the behavior of each component will be defined and updated based on its neighbors. The proposed hybrid method is characterized as simple, robust and parallel which keeps the important details of the image effectively. The proposed approach has been performed on well-known gray scale test images and compared with other conventional and famous algorithms, is more effective.

A new kind of impulse noise filter based on PCNN

Abstract: Median filter can inhibit the impulse noise in the image, but it always erodes or dilates the edges of images. H.S. Ranganath mentioned that impulse noise could be removed through modifying the intensity of those contaminated pixels step by step using PCNN. Obviusly, this method consumes much more time in computation. Combining the PCNN model with the median filter, this paper presents an impulse noise filter based on a simplified PCNN model which has less parameters. Not only can it remove the impulse noise effectively, but it also keeps the details of the images as much as possible. It can be verified through experiments and theoretical analysis that this kind of filter is superior to the normal median filter and the filter mentioned by H.S. Ranganath, whether in the aspect of noise removal or of keeping details.