1. An image processing method for scaling an image from an original resolution to a target resolution, wherein a pixel value P T of a target pixel point N T in the target resolution is theoretically composed of original pixel values P 1 -P K Of original pixel points N 1 -N K in the original resolution, and K is a positive integer larger than 1, the method comprising: finding theoretical combination ratios R 1 -R K corresponding to the original pixel points N 1 -N K ; converting the theoretical combination ratios R 1 -R K to corresponding weights W 1 -W K , wherein each of the corresponding weights W 1 -W K is an integer between 1 and 2 n , n is an integer, and the sum of the corresponding weights W 1 -W K is 2 n ; and calculating the original pixel values P 1 -P k with the corresponding weights W 1 -W K using a scaler, to generate the pixel value P T of the target pixel point N T and complete the image processing.