Abstract: Traditional image interpolation algorithm is good at global handling of images, but weak in dealing with edge details of images, thus leading to sawtooth lines in detail areas. For this problem, this paper proposes an image resolution and contrast enhancement algorithm. First, a high-resolution image is obtained from an original one by using wavelet zero padding algorithm, and the lost edge and texture features of the image are compensated by using residual error correction process. Then, directional cycle spinning operations are performed on the image. Considering that the high frequency components in horizontal, vertical and diagonal directions of the image after wavelet decomposition can reflect the edge changes in the image, we use high frequency components in different directions of the image to describe mutation degrees in corresponding directions of image pixels. According to the mutation degrees, an adaptive fusion process of cycle spinning operations is realized, which can avoid excessive suppression of edge details. Finally, a nonlinear enhancement function is used to improve image contrast and highlight edge and contour information, Experimental results show that this algorithm not only enhances the spatial resolution and contrast of images, but also retains the edge and contour information contained in original ones. Compared with other image interpolation algorithms, this algorithm shows improved performs both in visual effect and anti-noise ability.

Key words: wavelet zero padding, wavelet transform, cycle spinning, enhancement function, high resolution image reconstruction