Hierarchical requantization of depth data for 3D visual communications

Depth data is recognized as an important information in 3D visual communications. Whereas the representation, coding and transmitting of depth data is still an open problem, the depth data quality strongly also depend of its bit precision, i.e. how many bits are used to represent the depth signal. This paper addresses the efficient requantization of a n-bit depth data to a lower m-bit representation, in order to be compliant with classical video encoder input. The proposed depth mapping method to a lower m-bit precision is carried out through a binary space partition wherein the construction is based on histogram analysis. The resulting constrained optimization problem can be solved in O(2^m) time. Experimental results show that this new depth requantization strategy leads to a smaller quantization error and hence better synthesis novel views by Depth Image Based Rendering (DIBR).