Patent ID: 7298925

Claim:
A method for efficient scaling in the transform domain when transform coefficient data is provided as an input to a data processing system, comprising the steps of: providing transform coefficient data to the data processing system; generating a combined matrix for one-dimensional scaling; and the data processing system scaling data represented by the transform coefficient data in the transform domain by applying the combined matrix to said transform coefficient data; wherein generating the combined matrix comprises the steps of: selecting a rational scaling factor F; selecting a matrix dimension value m; and selecting a smallest integer g wherein (Fg)/m is an integer k; generating a first matrix operating on at least one (mg)×(m) matrix by: zeroing out at least one row or at least one column of said matrix; or inserting at least one row of zeros or at least one column of zeros into said matrix; generating a second matrix by applying a one-dimensional inverse transform to the first matrix; and generating a third matrix by regrouping said second matrix so that it is conceived of as being composed of k (m)×(m) matrices; and generating the combined matrix by applying a one-dimensional forward transform to said third matrix.