Image Resizing by Piecewise Quadratic Polynomial with Edge Constraints

Abstract

In the fleld of image resizing, general polynomial fltting surfaces which are based on the methods such as Lagrange, spline and least squared methods usually produce enlarged images with blurred edges. Our experiments showed, however, that when the edge information is used as a constraint to construct polynomial surfaces to resize the image, the enlarged image could preserve good edge characteristics and have better visual quality. A new method for constructing fltting patches to resize the image is presented. Associated with each pixel, a fltting patch is constructed using edge information as a constraint to make it have the shape suggested by the pixel and the adjacent pixels. The enlarged image pixels are computed by the combination of the points which are sampled from the fltting patches. The fltting patch has the quadratic polynomial precision. The new method has the advantages that it is easy to compute and produces the enlarged image with better visual quality and higher PSNR value. Comparison results of the new method with other methods are included.