An effective image enhancement filtering for noisy image sequences

This paper proposes a method of filtering a digital sensor image to efficiently reduce noise and to improve the sharpness of an image. To reduce the noise in an image captured by conventional image sensor, the proposed noise reduction filter selectively outputs one of results obtained by recursive temporal and spatial noise filtering values. By proposed noise filtering method, image detail can be well preserved and noise filtering artifacts which can be generated along the moving object boundary in image sequences by applying temporal noise filtering are prevented. Since the sharpness of noise filtered image can be inevitably deteriorated by noise filtering, the adaptive noise suppressed sharpening filter is also proposed. The proposed sharpening filter generates filter mask adaptively according to the pixel similarity information within filter mask and can obtain the continuous image quality by the easy-controllable gain control algorithm without noise boost-up in the smooth region.