Statistical analysis of the 2D-DCT coefficients of the differential signal for images

摘要

Block-matching motion compensation techniques are widely used in image coding algorithms. A differential signal with different characteristics from the original signal is then generated. It is important to know the statistical properties of the signal source in order to correctly characterize some parameters of the digital image coding scheme. In this paper a statistical study of the 2D-DCT coefficients of the motion-compensated blocks is performed. The results of this study indicate that the statistics of the coefficients are best approximated by a Laplacian pdf (probability density function). The influence of some types of normalization is investigated and the corresponding pdf's are estimated. An analysis indicates that the Laplacian pdf may be used as a good approximation for the statistical properties of the normalized coefficients.