Layer Assignment Based on Depth Data Distribution for Multiview-Plus-Depth Scalable Video Coding

Three dimensional (3-D) video is experiencing a rapid growth in a number of areas, including 3-D cinema, 3-D TV, and mobile phones. Several problems must be addressed to display captured 3-D video at another location. One problem is how to represent the data. The multiview plus depth representation of a scene requires a lower bit rate than transmitting all views required by an application and provides more information than a 2-D-plus-depth sequence. Another problem is how to handle transmission in a heterogeneous network. Scalable video coding enables adaption of a 3-D video sequence to the conditions at the receiver. In this paper, we present a scheme that combines scalability based on the position in depth of the data and the distance to the center view. The general scheme preserves the center view data, whereas the data of the remaining views are extracted in enhancement layers depending on distance to the viewer and to the center camera. The data is assigned into enhancement layers within a view based on depth data distribution. Strategies concerning the layer assignment between adjacent views are proposed. In general, each extracted enhancement layer increases the visual quality and peak signal-to-noise ratio compared to only using center view data. The bit-rate per layer can be further decreased if depth data is distributed over the enhancement layers. The choice of strategy to assign layers between adjacent views depends on whether quality of the fore-most objects in the scene or the quality of the views close to the center is important.