CORRELATION ANALYSIS OF DISCRETE COSINE TRANSFORM COEFFICIENTS OF IMAGE BLOCKS

А. И. Мирошниченко

Abstract


Task of lossy image compression based on discrete cosine transform (DCT) is considered. For image blocks having size 8x8 pixels (it corresponds to division of images on blocks in JPEG standard) presence of correlation between different DCT coefficients of the same block as well as between coefficients of different blocks is analyzed. Values of correlation coefficients are calculated and averaged for set of test images. It is shown that there is substantial correlation between absolute values of DCT coefficients of the same block, while correlation between signs of the coefficients is insignificant. It is shown also that correlation between DCT coefficients of adjacent blocks is smaller than the one for coefficients of the same block. At the same time there are noticeable correlations not only for absolute values but also for signs of coefficients. It is shown that position of DCT coefficient with maximum correlation with given coefficient can be effectively predicted using its indices.

Keywords


discrete cosine transform, Pearson correlation, traffic compression, lossy image compression, JPEG

References


Wallace, G. K. The JPEG Still Picture Compression Standard. Comm. Of the ACM, vol. 34, no. 4, 1991, pp. 30 - 44.

Taubman, D., Marcellin, M. JPEG 2000: Image Compression Fundamentals, Standards and Practice. – Boston, Kluwer Publ., 2002. 800 p.

Ponomarenko, N., Lukin, V., Egiazarian, K., Astola, J. ADCTC: A new high quality DCT based coder for lossy image compression. Proceedings of Interna tional Workshop on Local and Non-Local Approximation in Image Processing (LNLA). – Switzerland, August – 2008. – 6 p.

HD Photo format overview. Available at: https://msdn.micrsoft.com/ruru/library/windows/desktop /gg430023 (accessed 30.11.2016).

Tran, T., Nguyen. T. A lapped transform progressive image coder. Proceedings of the IEEE International Symposium on Circuits and Systems, vol. 4, June – 1998, pp. 1 - 4.

Sullivan, G.J., Ohm, J.-R., Han, W.-J., Wiegand T. Overview of the High Efficiency Video Coding (HEVC) Standard. IEEE Transactions of Circuits and Systems for Video Technology, vol. 22, no. 12, 2012, pp. 1649 - 1668.

Ponomarenko, N., Egiazarian, K., Lukin, V., Astola, J. Additional lossless compression of JPEG images. Proceedings of 4th Symposium on Image and Signal Processing and Analysis. – Croatia, September. – 2005. – pp. 117 - 120.

Rao, K., Yip, P. Discrete Cosine Transform, Algorithms, Advantages, Applications. – Academic Press. – 1990. – 512 p.

Ponomarenko, N.N., Bazhyna, A.V., Egiazarian, K.O. Prediction of signs of DCT coefficients in blockbased lossy image compression. Proceedings of the SPIE conference Image Processing: Algorithms and Systems V, vol. 6497, USA, January, 2007, 4 p.

ADCT: a new high quality dct based coder for lossy image compression. Available at: http://www.ponomarenko.info/adct.htm. (accessed 30.11.2016).




DOI: https://doi.org/10.32620/reks.2016.4.03

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