11 July 2012 Finding maximum JPEG image block code size
Author Affiliations +
Abstract
We present a study of JPEG baseline coding. It aims to determine the minimum storage needed to buffer the JPEG Huffman code bits of 8-bit image blocks. Since DC is coded separately, and the encoder represents each AC coefficient by a pair of run-length/AC coefficient level, the net problem is to perform an efficient search for the optimal run-level pair sequence. We formulate it as a two-dimensional, nonlinear, integer programming problem and solve it using a branch-and-bound based search method. We derive two types of constraints to prune the search space. The first one is given as an upper-bound for the sum of squares of AC coefficients of a block, and it is used to discard sequences that cannot represent valid DCT blocks. The second type constraints are based on some interesting properties of the Huffman code table, and these are used to prune sequences that cannot be part of optimal solutions. Our main result is that if the default JPEG compression setting is used, space of minimum of 346 bits and maximum of 433 bits is sufficient to buffer the AC code bits of 8-bit image blocks. Our implementation also pruned the search space extremely well...
© 2012 SPIE and IS&T
Gopal Lakhani, Gopal Lakhani, } "Finding maximum JPEG image block code size," Journal of Electronic Imaging 21(3), 033003 (11 July 2012). https://doi.org/10.1117/1.JEI.21.3.033003 . Submission:
JOURNAL ARTICLE
8 PAGES


SHARE
Back to Top