Detail and contrast enhancement for images using dithering based on complex wavelets

This paper introduces a new method for compensating the softening effects arising because of error diffusion based dithering. The proposed method is based on complex wavelet transforms (CWT) and has been named as complex wavelet based dithering. Similar to the wavelet based dithering, the proposed method emphasizes on details and contrast of an image. But, unlike wavelet based dithering it also provides better shift invariance and better directionality, resulting in better detail and contrast enhancement respectively. The proposed method compares favorably to two typical image dithering methods, namely, error diffusion and wavelet based dithering, in terms of the root mean square error and the peak signal to noise ratio.