Stephen R. Smoot and Lawerence A. Rowe
Computer Science Division
University of California at Berkeley
Berkeley, CA 94720-1766
E-mail: (smoot@plateau.cs.berkeley.edu
/ Rowe@cs.berkeley.edu)
Phone: (510) 643-7106 or (510) 642-5117
Many image and video compression schemes perform the discrete cosine transform
(DCT) to represent image data in frequency space. An analysis of a broad suite
of images confirms previous finding that a Laplacian distribution can be used
to model the luminance AC coefficients. This model is expanded and applied to
color space (Cr/Cb) coefficients. In MPEG, the DCT is used to code interframe
prediction error terms. The distribution of these coefficients is explored. Finally,
the distribution model is applied to improve dynamic generation of quantization
matrices. Keywords: DCT, quantization, JPEG, MPEG, video compression