10-06-2017, 07:09 AM
A Low-Cost VLSI Implementation for Efficient Removal of Impulse Noise
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INTRODUCTION
Applications such as printing skills, medical imaging,scanning techniques, image segmentation, and face recognition,images are often corrupted by noise in the process of image acquisition and transmission. Hence, an efficient denoising technique is very important for the image processing applications . Recently, many image denoising methods have been proposed to carry out the impulse noise suppression.
DRID(Differential Rank Impulse Detector)
The impulse detector of DRID is based on a comparison of signal samples within a narrow rank window by both rank and absolute value.
Where .
Compare to NID more nubmer of pixels get misdetected.
This method is not good enough with regard to edge preservation.
ATMBM( Alpha-trimmed Mean-based method )
It uses the alpha-trimmed mean in impulse detection and replaced the noisy pixel value by a linear combination of its original value and the median of its local window.
Where .
This method is not good enough with regard to edge preservation.
SEPD Overview
We adopt 3X3 mask W centered on pixel to be denoised.
We considering pixels of the first row are already denoised in previous processes.
SEPD will find whether
is noisy pixel or not. If +ve , it locates directional edge exist in W & uses it determine reconstructed value
Register bank
The register bank (RB), consisting of 9 registers, used to store the 3 x 3 pixel values of the current mask.
The denoising process for does not start untill enters from input device.
The nine values stored in RB are then used simultaneously by subsequent extreme data detector and noise filter for denoising.