Region of interest coding for low bit rate image transmission

Region of interest (ROI) coding has become a new challenge for low bandwidth media channels. This paper presents an original method for low bit rate compression using this concept. It is based on a new progressive coding technique called LAR (Locally Adaptive Resolution) combining a spatial nonuniform sampling and a variable block-size spectral transform. Only little overhead is required for the ROI shape description, and the data structure enabling the inner ROI enhancement is totally correlated to this shape. This technique is also very fast, allowing real-time and interactive multimedia applications