A texture feature preserving image interpolation algorithm via gradient constraint

In this paper, a type of bivariate rational interpolation function is constructed for preserving image texture structure, which integrates polynomial function with rational function. On the basis of this model, an image interpolation algorithm for texture feature preserving is proposed. Firstly, isolines method is employed to divide image into smooth region and non-smooth region. Secondly, the smooth region and the non-smooth region are interpolated by polynomial model and rational model respectively. Finally, in order to preserve image texture direction, the pixel value of the interpolation point is determined by objective function that is constructed based on the gradient. Experimental results show that the proposed algorithm achieves good competitive performance compared with the state-of-the-art interpolation algorithms, especially in preserving image details and structure of edge.