Region-based scalable coding for video communications

Abstract

This paper presents a region-based scalable coding technique that can be used in interactive transmission of images over networks. This method has a capability of near lossless coding for a specific region of interest (ROI), while the rest of the region is coded with a high quality lossy codec. The enhancement layers add refinement to the quality of the images that have been reconstructed using the basic layer of the intra frame. The proposed coding technique uses multiple quantizers with thresholds (QT) for layering and it creates a bit plane for each layer of both the intra and residual frames. The bit plane is then partitioned into sets of small areas to be coded independently. Run-length and entropy coding are applied to each of the sets to provide scalability for the entire image sets resulting in high picture quality in the end user-specified ROI. We tested this technique by applying it to various test image sequences and we consistently achieved a high level of performance.