Noise reduction

(redirected from Despeckle)

noise reduction

[′nȯiz ri‚dək·shən]
(engineering acoustics)
A process whereby the average transmission of the sound track of a motion picture print, averaged across the track, is decreased for signals of low level; since background noise introduced by the sound track is less at low transmission, this process reduces noise during soft passages.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

Noise reduction

Reducing the level of unwanted sound by any of several means of acoustical treatment.
Illustrated Dictionary of Architecture Copyright © 2012, 2002, 1998 by The McGraw-Hill Companies, Inc. All rights reserved

noise reduction, NR

The difference in decibels between the average sound pressure levels produced in two rooms by a sound source in one of them.
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.
References in periodicals archive ?
Radlak in Poland "Digital Path Approach Despeckle Filter for Ultrasound Imaging and Video" propose a so-called escaping paths based on traditional digital paths, and also, they extend this concept from the spatial domain (2D) to the spatiotemporal domain (3D) that is designed for multiplicative noise suppression, specifically for ultrasound image and video filtering.
The Despeckle and the Remove Outliers commands under Process [right arrow] Noise can be applied to remove isolated pixels or small pixel groups.
Secondly, the selected area is preprocessed for despeckle; the despeckle algorithm of speckle reducing anisotropy diffusion (SRAD) [24] is used here.
Cheng, "Comparison of despeckle filters for breast ultrasound images," Circuits, Systems, and Signal Processing, pp.
Based on the detected structure types, the proposed despeckle method employs a 2D median filter, a 1D Gaussian filter, and a 2D Gaussian filter to suppress speckles and enhance features.
Thus, we propose to despeckle an SAR image by minimizing the L0-norm of the difference of average of the image.
NC values of extracted watermark are 1 against, Sharpen, Sharpen Edge, Unsharp Mask, Auto Contrast and Equalize attacks, as well as, NC values are 0.9861, 0.9653 respectively, after the despeckle, gaussian (3%) attacks.
While in [37] an extensive list of despeckle filtering algorithms is provided, which includes methods based on linear filtering (first-order statistics, local statistics, etc.), nonlinear filtering (median, linear scaling, etc.), diffusion filtering (anisotropic diffusion, etc.), and wavelet filtering, we also mention that methods following a VST-like approach [39] can be also an effective alternative.
The methods are - Spatial for high frequency or fine noise, Threshold for light grain, Temporal for heavy or large grain and noise patterns, and Despeckle for uneven grain and/or noise.