Impulse Noise Detection and Removal Using First Order and Second Order Difference with Multistage Directional Statistics

2014 ◽  
Author(s):  
Saqib Rasheed ◽  
Ayyaz Hussain
Keyword(s):  
Impulse Noise ◽  
Second Order ◽  
Noise Detection ◽  
Directional Statistics ◽  
Order Difference ◽  
First Order ◽  
Impulse Noise Detection

A Denoising Mixed Noise Method Based on Median Filter and Lifting Wavelet Technology

2013 ◽  
Vol 411-414 ◽  
pp. 1546-1551 ◽  
Author(s):  
Zhong Tao Qiao ◽  
Feng Qi Gao ◽  
Guang Long Wang ◽  
Liang Liang Chang
Keyword(s):  
Impulse Noise ◽  
Median Filter ◽  
Detection Algorithm ◽  
Noise Detection ◽  
Image Digitization ◽  
Mixed Noise ◽  
The Common ◽  
Lifting Wavelet ◽  
Impulse Noise Detection ◽  
Suppress Noise

In image digitization and transmission, images often suffer contamination inevitably. The noises in images often consist of Gaussian noise and impulse noise. The common denoising algorithms are capable of removing single one of them. In order to remove those two types of noise, a composite algorithm is proposed. Firstly, based on median filter, an impulse noise detection algorithm is used to filter impulse noise. Secondly, adaptive directional lifting wavelet (ADL) and normal lifting wavelet is combined to suppress noise from image signal and protect the texture edge from loss simultaneously. Meanwhile an improved half-soft threshold is used for normal lifting wavelet. At last, simulations show that this technology can suppress Gaussian and impulse noise in image efficiently．

The Boogie-Woogie Illusion

Perception ◽  
10.1068/p3378 ◽  
2002 ◽  
Vol 31 (8) ◽  
pp. 1005-1011 ◽  
Author(s):  
Patrick Cavanagh ◽  
Stuart Anstis
Keyword(s):  
Second Order ◽  
Order Difference ◽  
First Order ◽  
Luminance Difference ◽  
Order Pattern

A grid of vertical and horizontal lines, each composed of light and dark squares, is moved rigidly at 45° to the vertical on a gray surround. When the luminance of the background is set midway between the luminances of the light and dark squares, the squares appear to race along the lines even though they are actually ‘painted’ on the lines. The effect arises from the unequal apparent speeds of the lines and their textures. The light and dark squares along the lines define a first-order pattern whose apparent speed, parallel or along the line, is close to veridical. The lines themselves have no overall luminance difference from the background so that they are defined by a second-order difference. As reported elsewhere, apparent speed is reduced for second-order motion so that the motion perpendicular to the line is perceived as slower than the motion along the line even though they are physically equal. The imbalance creates the impression that the small squares are moving along the lines rather than moving rigidly with them.

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