Trilateral Filtering for Image Interpolation

In this paper, we deal with problems of contour jaggies and blurring artifacts appeared in conventional image interpolation schemes, and present a new image interpolation method called trilateral filtering. The method exploits the smooth varying behaviour of natural image contours, and tries to overcome the contour jaggies problem by suppressing edge convex corner pixels. It first gives a primary estimate of unknown pixels by their four nearest neighbours with proper weights, which are determined by the corresponding edge degree information and spatial distance. Then, in order to give sharper edges, photometric similarities are introduced to further refine the weights, based on which, final estimate of unknown pixels obtained. Simulation results show that the proposed scheme produces fewer artifacts and sharper edges compared to conventional methods, and still preserves simplicity and efficiency compared to more advanced ones.