A Generic Filtering Method for Removing Artefacts from Color and Contrast Modifications of Digital Images
Usharani Ghattamaneni · 2014
Abstract — A generic Filtering method to remove artefacts from color and contrast modifications of digital images is presented. This work is concerned with the color and contrast modifications and compression of digital images. Contrast stretching, Gamma correction and histogram equalization or specifications are example techniques to get those modifications and standard JPEG, JPEG2000 are example compression techniques of digital images. A common drawback of most methods aiming at modifying the contrast or color content of images and compression of images is their strong tendency to create visual artefacts Such as attenuation of details and textures. In this paper, Adaptive Histogram equalization, jpeg compression and decompression techniques are applied on digital image which leads to some visual artefacts. Then Transportation map which is the difference between original image and transformed image is calculated, then a generic filtering method also called TMR filter which draws on the nonlocal Yaroslavsky filter is used to regularize the transportation map so that artefacts are suppressed. The performance of this method is evaluated through measures such as MSE, PSNR and Variance. Performance measures such as MSE, PSNR and Variance are calculated over Transformed image and TMR Filtered image and compared. The results are compared with related approaches such as mean, median and wiener filtering of transformed images and discussed..