1. A method for scaling up an image, the method converting a source image with M*N pixels into a target image with KM*HN pixels, wherein M, N, K and H are integers and the method comprises the following steps: choosing one pixel from the source image as a processing pixel; determining a characteristic pattern according to the processing pixel and a plurality of neighboring pixels close to the processing pixel in the source image; generating a pixel compensation matrix according to the characteristic pattern; generating K*H target pixels according to a pixel value of the processing pixel and the pixel compensation matrix; and repeating the above-mentioned steps until all pixels of the source image are processed.