Optimal nonlinear interpolation of image line scans

This paper describes and illustrates an optimal nonlinear interpolation method that is appropriate for image line scans. It is particularly suitable for the restoration of digital images corrupted by "salt and pepper" noise in which isolated pixels are driven to their minimum or maximum gray values. It assigns gray values to these pixels so that the original smoothness of each line scan is maintained. The method is significant in that smoothness invariance is not achieved using, for example, ordinary low-pass or standard wavelet filtering methods to remove "salt and pepper" noise.