Impulse noise

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

Design and Development of an Improved Adaptive Median Filtering Method for Impulse Noise Detection

Abstract: An Impulse noise detection and removal with adaptive filtering approach is proposed to restore images corrupted by salt & pepper noise. The proposed algorithm works well for suppressing impulse noise with noise density from 5 to 60% while preserving image details. The difference of current central pixel with median of local neighborhood pixels is used to classify the central pixel as noisy or noise-free. The noise is attenuated by estimating the values of the noisy pixels with a switching based median filter applied exclusively to those neighborhood pixels not labeled as noisy. The size of filtering window is adaptive in nature, and it depends on the number of noise-free pixels in current filtering window. Simulation results indicate that this filter is better able to preserve 2-D edge structures of the image and delivers better performance with less computational complexity as compared to other denoising algorithms existing in literature.

A Robust Edge Detection Approach in the Presence of High Impulse Noise Intensity Through Switching Adaptive Median and Fixed Weighted Mean Filtering

Abstract: This paper introduces a robust edge detection method that relies on an integrated process for denoising images in the presence of high impulse noise. This process is shown to be resilient to impulse (or salt and pepper) noise even under high intensity levels. The proposed switching adaptive median and fixed weighted mean filter (SAMFWMF) is shown to yield optimal edge detection and edge detail preservation, an outcome we validate through high correlation, structural similarity index, and peak signal-to-noise ratio measures. For comparative purposes, a comprehensive analysis of other denoising filters is provided based on these various validation metrics. The non-maximum suppression method and new edge following maximum-sequence are the two techniques used to track the edges and overcome edge discontinuities and noisy pixels, especially in the presence of high-intensity noise levels. After applying predefined thresholds to the grayscale image, and thus obtaining a binary image, several morphological operations are used to remove the unwanted edges and noisy pixels and perform edge thinning to ultimately provide the desired edge connectivity, which results in an optimal edge detection method. The obtained results are compared with other existing state-of-the-art denoising filters and other edge detection methods in support of our assertion that the proposed method is resilient to impulse noise even under high-intensity levels.

$\ell _0$ TV: A Sparse Optimization Method for Impulse Noise Image Restoration

Abstract: Total Variation (TV) is an effective and popular prior model in the field of regularization-based image processing. This paper focuses on total variation for removing impulse noise in image restoration. This type of noise frequently arises in data acquisition and transmission due to many reasons, e.g., a faulty sensor or analog-to-digital converter errors. Removing this noise is an important task in image restoration. State-of-the-art methods such as Adaptive Outlier Pursuit(AOP) [1] , which is based on TV with $\ell _{02}$ -norm data fidelity, only give sub-optimal performance. In this paper, we propose a new sparse optimization method, called $\ell _0TV$ -PADMM, which solves the TV-based restoration problem with $\ell _0$ -norm data fidelity. To effectively deal with the resulting non-convex non-smooth optimization problem, we first reformulate it as an equivalent biconvex Mathematical Program with Equilibrium Constraints (MPEC), and then solve it using a proximal Alternating Direction Method of Multipliers (PADMM). Our $\ell _0TV$ -PADMM method finds a desirable solution to the original $\ell _0$ -norm optimization problem and is proven to be convergent under mild conditions. We apply $\ell _0TV$ -PADMM to the problems of image denoising and deblurring in the presence of impulse noise. Our extensive experiments demonstrate that $\ell _0TV$ -PADMM outperforms state-of-the-art image restoration methods.

In-Flight Far-Field Measurement of Helicopter Impulsive Noise

Abstract: : An in-flight technique for measuring UH-1H helicopter impulsive noise (sometimes called 'blade slap') by stationkeeping with a quiet instrumented lead aircraft was found to be highly successful. Far-field quantitative acoustic waveforms and radiation patterns were easily obtained over a wide, continuous range of UH-1H flight conditions, including several areas known to produce annoying acoustic radiation. The data collected using this technique were not (to any significant degree) contaminated by transmission path distortions that have hindered measurement efforts in the past. The two major finding of this initial measurement program were: (1) Judging the occurrence and severity of a helicopter's radiated impulsive noise signature from cabin-based noise measurements can be misleading. For the UH-1H helicopter, reduction in cabin audible impulsive noise levels may constitute a necessary but certainly not sufficient to indicate that far-field impulsive noise radiation has been reduced. The following three distinct types of impulsive noise are radiated by the Un-1H helicopter while flying between 80 and 115 knots at descent rates from zero to 1000 ft/min: (a) A series of positive pressure pulses believed to be related to blade-tip vortex interaction. These pulses are responsible for the crisp popping sound of the radiated noise; (b) A negative pressure disturbance that rapidly increases in amplitude with forward velocity, becoming quite intense and sawtoothed in shape at 115 knots IAS; and (c) A narrow positive pressure spike that closely follows that sawtooth-shaped negative pressure pulse at high airspeeds (115 knots).

Coded M-FSK for power line communications

Abstract: We discuss the application of coded modulation for power line communications. We combine M-FSK with permutation codes to include frequency and time diversity. This makes the transmissions robust against permanent frequency disturbances and impulse noise. The scheme is applicable to any frequency range.