Impulse noise

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

Combined higher order non-convex total variation with overlapping group sparsity for impulse noise removal

Abstract: A typical approach to eliminate impulse noise is to use the l1-norm for both the data fidelity term and the regularization terms. However, the l1-norm tends to over penalize signal entries which is one of its underpinnings. Hence, we propose a variational model that uses the non-convex lp-norm, 0 < p < 1 for both the data fidelity and a second-order total variation regularization term combined with an overlapping group sparse regularizer. Specifically, to robustly eliminate impulse noise, the proposed method uses a non-convex data fidelity term. The hybrid combination of a second-order non-convex total variation and an overlapping group sparse regularization term is used to eliminate the remaining staircase artifacts while maintaining a sharp restored image. A mathematical formulation is derived and to implement it, the iterative re-weighted l1 (IRL1) based alternating direction method of multipliers (ADMM) is used to solve the constraints and the subproblems. Experimental results for image denoising and deblurring on several widely used standard images demonstrate that the proposed method performed better when compared to the l1-norm total variation (TV), total generalized variation (TGV) model, and the non-convex lp-norm TV-based data fidelity model in terms of peak signal-to-noise ratio (PSNR) and structure similarity index measure (SSIM).

A Multiphase Image Segmentation Based on Fuzzy Membership Functions and L1-Norm Fidelity

Abstract: In this paper, we propose a variational multiphase image segmentation model based on fuzzy membership functions and L1-norm fidelity. Then we apply the alternating direction method of multipliers to solve an equivalent problem. All the subproblems can be solved efficiently. Specifically, we propose a fast method to calculate the fuzzy median. Experimental results and comparisons show that the L1-norm based method is more robust to outliers such as impulse noise and keeps better contrast than its L2-norm counterpart. Theoretically, we prove the existence of the minimizer and analyze the convergence of the algorithm.

Design of acoustic transmission along drill strings for logging while drilling data based on adaptive NC-OFDM

Abstract: This paper represents a new scheme using the drill strings as the medium to deliver logging information via a compressional acoustic wave. Considering the comb-type frequency characteristics of an acoustic channel, non-contiguous orthogonal frequency division multiplexing (NC-OFDM) has been selected as a promising technique for achieving high-rate transmission with high spectral efficiency and immunity to multipath channels. However, the irregular pilot design and high peak-to-average power ratio (PAPR) halted the widespread application of NC-OFDM. To overcome these two disadvantages, we propose an adaptive pilot design scheme in which the dynamic range of available frequency is pre-simulated and an improved discrete Fourier transformation based least square (PDFT-LS) channel estimation scheme to obtain the channel characteristics and an improved selected mapping (PSLM) scheme with low-complexity to reduce the PAPR of the transmitter are applied. Computer simulation and circuit test results are presented to demonstrate that the data transmission rate can be in excess of 500 bps along a 53.76 m experimental channel under the conditions of the simulated impulse noise and surface noise with a low bit error rate (BER), and the PAPR reduction performance can reach almost the same as that of a conventional SLM (CSLM) scheme.

Review of Impulse Noise Reduction Techniques

Abstract: This Paper presents survey of impulse noise reduction techniques. In this paper around ten most popular techniques are implemented and compared. Results of all algorithms are analyzed and efficiency of algorithms is calculated. Algorithms are tested using different types of images i.e. MRI, space, Television images etc. This survey provides complete knowledge of noise reduction techniques and also it helps researchers in selecting best impulse noise reduction algorithm. Keyword- Impulse Noise, Adaptive Median Filter, Image Enhancement and Noise Detection.