Compression and transmission of depth maps for image-based rendering

We consider applications using depth-based image-based rendering (IBR), where the synthesis of arbitrary views occur at a remote location, necessitating the compression and transmission of depth maps. Traditional image compression has been designed to provide maximum perceived visual quality, and a direct application is sub-optimal for depth-map compression, since depth-maps are not directly viewed. In other words, the sensitivity of the rendering error depends on the image content as well as on the depth map, we propose two improvements to take this into account. Firstly, we consider region-of-interest (ROI) coding, where we identify those regions of the image where accurate depth is most crucial. Secondly, we reshape the dynamic range of the depth map. Our experiments show a significant improvement in coding gain (1.1 dB) and rendering quality when we integrated these two improvements into a standard JPEG-2000 coder