Patent ID: 7050656

Claim:
A method for downscaling an image to a given target size, comprising the steps of: extracting a plurality of N×N blocks of transform coefficients representing data of the image to be downscaled; and transforming each of the extracted N×N blocks of transform coefficients into a k×k matrix of pixel values from the downscaled image, wherein the transformation from an N×N block of transform coefficients Y into a k×k matrix of pixel values X is achieved as follows: X=(k/N)D k T Y k D k , where 1≦k≦8, Y k is the top-left k×k sub-matrix of Y, and D k T is the transpose of D k which is defined by: D k (i,j)=(2/k) 1/2 α i cos [(2j+1)iπ/2k], with α i =1/√{square root over (2)} for i=0 and 1 otherwise.