Fast recursive algorithms for 2-D discrete cosine transform

摘要

A new algorithm for computation of two-dimensional (2-D) type-III discrete cosine transform is presented. The algorithm is particularly suited to block size (P_1 *2~m) by (P_2 *2~n), where p_1 and p_2 are odd integers, and m and n are non-negative integers. It shows that the 2-D type-III DCT can be decomposed into cosine-cosine, cosine-sine, sine-cosine, sine-sine sequences, which can be further decomposed into similar sequences. The proposed algorithm provides the flexibility in choosing block size and has a simple indexing mapping scheme and a fairly regular computation structure. The algorithm also requires a smaller number of arithmetic operations for p-1 = p_2 = 3.