1. An image enlargement method, the method comprising: inputting a low-resolution image, wherein the low-resolution image comprises 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; 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 steps of searching one matching area, finding a second pixel point, and performing local interpolation until processing for all the matching areas is complete, and obtaining an initial high-resolution image according to all of the intermediate pixel values; performing global interpolation for the initial high-resolution image to obtain a high-resolution image; and wherein performing local interpolation for the second pixel point according to the optimal contour template comprises: calculating an oriented function of an interpolation of the second pixel point according to an optimal contour template of a matching area of the first pixel point corresponding to the second pixel point, and performing the local interpolation for the second pixel point according to the oriented function of the interpolation of the second pixel point.