Non-essentiality of correlation between image and depth map in free viewpoint image coding: Accurate depth map case

We show non-essentiality of using a correlation between an image and a depth map for depth-image-based rendering (DIBR), when we use an accurate depth map. For coding of DIBR, an edge preserving filter, which jointly use the image and the depth map, as a post filter is a suitable approach. The joint filter not only removes coding distortion, but also improves accuracy of the coded depth map itself. Considering the development 3D technology, the accuracy of the input depth map will be improved. If we use an accurate depth map, e.g. the ground truth, the accuracy improvement of the joint filter becomes little. To reveal the fact, we use various codecs (JPEG, JPEG2000, and H.264/AVC) and use two state-of-the-arts filters, which are the post filter set as the non-joint filter, and the weighed mode filter as the joint filter. Experimental results show that the post filters do not require the joint image, and self-sustained types of the non-joint filter have better performance.