1. An image enlargement method, comprising the following steps: inputting a low-resolution image, wherein the low-resolution image comprises at least one matching areas and the matching areas are used to match all contour templates in a contour template set; searching one matching area for an optimal contour template, wherein the optimal contour template is a contour template with a minimum total variation value in the matching area and the contour template set; finding a second pixel point according to a zoom ratio and a first pixel point in the matching area, wherein the second pixel point is corresponding to the first pixel point; performing local interpolation for the second pixel point according to the optimal contour template, so as to obtain an intermediate pixel value; repeating the foregoing steps until processing for all the matching areas is complete, and obtaining an initial high-resolution image according to all of the intermediate pixel values; and performing global interpolation for the initial high-resolution image to obtain a high-resolution image.