| 摘要 |
<p> The invention relates to an encoding method for the compression of a video sequence including successive frames organized in groups of frames. Each frame is decomposed by means of a three-dimensional (3D) wavelet transform leading to a given number of successive resolution levels. This method is based on the SPIHT algorithm that transforms the original set of picture elements (pixels) of each group of frames into transform coefficients constituting a hierarchical pyramid in which a spatio-temporal orientation tree - in which the roots are formed with the pixels of the approximation subband resulting from the 3D wavelet transform and the offspring of each of these pixels is formed with the pixels of the higher subbands corresponding to the image volume defined by these root pixels - defines the spatio-temporal relationship. According to the invention, a full exploration of the subbands is performed during the initialization step of the process, and the set significance level of each subtree in the root pixels is calculated and stored. In the sorting step for the process, a comparison between said set significance level and the current significance level n replaces the call to the function that computes the significance of a tree relatively to n.</p> |
