Three-dimensional-DCT pipe coding

The paper reports on a video sequence coding method taking advantage of the generic video- communication layout: some moving objects on a still background. The algorithm operates on groups of frames in which the whole digital video sequence is divided, that implies the synchronization requirements' satisfaction and an acceptable level of compatibility with standard video coding (H.261, MPEG, etc.). An analysis of the spatial-temporal continuum, represented by each group of frames, is performed, in order to detect a tridimensional segmentation that identifies the moving objects by means of spatial regions. These regions can spread, as a sort of `pipes,' through the whole group of frames in the temporal direction. Various pipes' construction and coding strategies, including techniques based on object recognition and coding, are allowed. In this work a pipes' identification method based on fixed size moving blocks and their coding by means of a 3D-DCT transform is reported. The above method allows adjacent starting pipes to part themselves, leaving uncoded stripes at their boundaries. The proposed method does not imply the stripes coding, while it minimizes their number and the amount of the artifacts generated by their presentation. As a final topic, the paper reports some considerations on the coding efficiency related to the quality of the reconstructed sequences and on the compatibility characteristics.