1. An image processing method, comprising: (a) performing edge detection to an image to obtain a plurality of edge pixels of the image; (b) performing partial point-spread function (PSF) estimation to each of the edge pixels for different parts of the image to generate a plurality of partial PSF estimation results respectively corresponding to the parts of the image, wherein the partial PSF estimation comprises: (b1) setting a range to be processed according to an edge pixel to be processed; (b2) sampling the pixels in the range to be processed to generate the partial PSF estimation results; and (b3) if a pixel value of a specific pixel in the range to be processed is smaller than pixel values of the edge pixels to be processed, do not perform the partial PSF estimation to the specific pixel and the edge pixels; and (c) generating a PSF estimation result for whole the image according to the partial PSF estimation results.