Theoretical analysis on optimum word length assignment for integer dct
Masahiro Iwahashi, K. Nakagawa, Somchart Chokchaitam, Yoshihide Tonomura · 2005
Recently JPEG 2000 has adopted the integer wavelet to attain "lossless" coding of images. However existing DCT based "lossy" coding still prevails all over the world. This paper focuses on the integer DCT which can perform "lossless" coding maintaining compatibility to the "lossy" DCT coding. So far, we have optimized word length of each multiplier in the integer DCT considering colored spectrum of input image signal. However it is remained unknown that 1) Is the assigned word length robust to change of input signal? 2) How does it depend on structure of the transform? This report is intended as an investigation of theoretical analysis to answer such questions.