Discrete cosine transform: algorithms, advantages, applications
Discrete cosine transform: algorithms, advantages, applications
Vector quantization and signal compression
Vector quantization and signal compression
JPEG Still Image Data Compression Standard
JPEG Still Image Data Compression Standard
IEEE Transactions on Image Processing
Modeling DCT coefficients for fast video encoding
IEEE Transactions on Circuits and Systems for Video Technology
Complexity-distortion tradeoffs in variable complexity 2-D DCT
ACM-SE 42 Proceedings of the 42nd annual Southeast regional conference
Proceedings of the 15th international conference on Multimedia
Fast model-based test case classification for performance analysis of multimedia MPSoC platforms
CODES+ISSS '09 Proceedings of the 7th IEEE/ACM international conference on Hardware/software codesign and system synthesis
MPEG-21 standardization process: organization and rate distortion modeling for network adaptation
ICCOM'10 Proceedings of the 14th WSEAS international conference on Communications
| Hi-index | 0.00 |
In applications where compression has to be performed under varying complexity constraints (e.g. with hardware having to operate in reduced power mode) it is beneficial to design compression algorithms that allow some degree of complexity scalability. In this paper we explore complexity scalability for transform coding algorithms.We show that a variable complexity algorithm (VCA), which uses energy thresholds to determine the number of coefficients to be computed for each input, is preferable to other alternatives such as a pruned transform, where the same number of coefficients is computed for the whole image. We show that the benefits include not only a higher degree of scalability, but also increased compression performance, as we take advantage of the energy classification that is needed for VCA operation and design quantizers that match each class. We provide expressions for the average complexity, as well as rate/distortion relations for a generic N-point VCA transform.For a two-point case, we present closed-form relations describing the variance changes in two classes. In addition, rate-distortion-complexity relations are also empirically obtained. We apply VCA to eight-point KLT and 8x8 DCT in the JPEG framework and experiments show that the VCA approach is superior in rate/distortion performance at low rates as compared to the standard transform coding techniques.