Topic
Impulse noise
About: Impulse noise is a research topic. Over the lifetime, 4816 publications have been published within this topic receiving 63970 citations.
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TL;DR: The analytic properties of the resulting new functional ℱ, defined in terms of edge-preserving potential functions φα, inherits many nice properties from φ α, including the first and second order Lipschitz continuity, strong convexity, and positive definiteness of its Hessian.
Abstract: Recently, a powerful two-phase method for restoring images corrupted with high level impulse noise has been developed. The main drawback of the method is the computational efficiency of the second phase which requires the minimization of a non-smooth objective functional. However, it was pointed out in (Chan et al. in Proc. ICIP 2005, pp. 125---128) that the non-smooth data-fitting term in the functional can be deleted since the restoration in the second phase is applied to noisy pixels only. In this paper, we study the analytic properties of the resulting new functional ?. We show that ?, which is defined in terms of edge-preserving potential functions ? ? , inherits many nice properties from ? ? , including the first and second order Lipschitz continuity, strong convexity, and positive definiteness of its Hessian. Moreover, we use these results to establish the convergence of optimization methods applied to ?. In particular, we prove the global convergence of some conjugate gradient-type methods and of a recently proposed low complexity quasi-Newton algorithm. Numerical experiments are given to illustrate the convergence and efficiency of the two methods.
46 citations
Patent•
13 Dec 2000TL;DR: In this paper, the error rate performance of short data packets in cable modems in an impulsive noise environment is improved by initializing a cable modem on more than one channel.
Abstract: A single carrier cable modem can be initialized on multiple channels. By initializing a cable modem on more than one channel, the error rate performance of short data packets in cable modems in an impulsive noise environment is improved. The advantage of low symbol rate transmission for short packets in an impulse noise environment is achieved without sacrificing burst capacity at a cable modem and without the complexity of transmitting multiple symbol waveforms simultaneously at a cable modem.
46 citations
Patent•
15 Sep 1995
TL;DR: In this article, a method and device of comfort noise generation for echo cancelers is described, where the actual background noise of a channel is stored in a noise buffer and when the echo suppressor is activated by the echo canceler to suppress any unwanted signals on the channel, the buffer provides the stored noise to the channel to provide continuous background noise.
Abstract: The invention describes a method and device of comfort noise generation for echo cancelers. The invention stores the actual background noise of a channel in a noise buffer. When the echo suppressor is activated by the echo canceler to suppress any unwanted signals on the channel, the buffer provides the stored noise to the channel to provide continuous background noise. To ensure that neither speech nor impulse noise enters the buffer, hangover delays and energy threshold levels are provided such that signals within the delay period or signals which exceed the energy threshold level are screened from entering the buffer.
46 citations
31 May 1998
TL;DR: A computationally efficient algorithm is proposed to remove noise impulses from speech and audio signals while retaining its features and tonal quality based on the SD-ROM (Signal Dependent Rank Order Mean) algorithm.
Abstract: A computationally efficient algorithm is proposed to remove noise impulses from speech and audio signals while retaining its features and tonal quality. The proposed method is based on the SD-ROM (Signal Dependent Rank Order Mean) algorithm. This technique has successfully been used to remove impulse noise from images. It has the advantage of being relatively fast, simple and robust. The algorithm estimates the likelihood the sample under inspection is corrupt relative to the neighboring samples and replaces a sample detected as corrupted by a value based on the neighboring samples. This algorithm also has the advantage of being 'configurable' to the type of noise impulses in the sample, as the thresholds used to detect noise impulses can be varied to suit the signal.
46 citations
TL;DR: In this paper, a decision-based approach has been used for the removal of impulse noise in image denoising, which can primarily preserve image details while suppressing impulsive noise.
Abstract: Noise is a major issue while transferring images through all kinds of electronic communication. One of the most common noise in electronic communication is an impulse noise which is caused by unstable voltage. In this paper, the comparison of known image denoising techniques is discussed and a new technique using the decision based approach has been used for the removal of impulse noise. All these methods can primarily preserve image details while suppressing impulsive noise. The principle of these techniques is at first introduced and then analysed with various simulation results using MATLAB. Most of the previously known techniques are applicable for the denoising of images corrupted with less noise density. Here a new decision based technique has been presented which shows better performances than those already being used. The comparisons are made based on visual appreciation and further quantitatively by Mean Square error (MSE) and Peak Signal to Noise Ratio (PSNR) of different filtered images..
46 citations