Efficient region-based motion estimation and symmetry oriented segmentation for image sequence coding

In the paper an efficient coding system for very low bit rates is presented. It is characterized by three operating modes. The intraframe mode combines image segmentation and an efficient luminance representation focalized on the concept of symmetry. The motion compensated mode is based on an adaptive motion representation which provides a good trade-off between the cost of parameter transmission and the quality of prediction. The obtained motion vector field is used for the reconstruction in the predicted mode. Experimental results are given on four test sequences. Simulations show good performance of the coding system both in terms of PSNR and bitrate. In particular, experiments show that the system is capable of working at around 24 kbit/sec with good quality for head-and-shoulder sequences. With more complex sequences, 50 kbit/sec are reached with acceptable degradation of the reconstructed images