Depth Image-Based Representation and Compression for Static and Animated 3-D Objects

Abstract—This paper describes a new family of three-dimen-sional (3-D) representations for computer graphics and animation, called depth image-based representations (DIBR), which have been adopted into MPEG-4 Part16: Animation Framework eXtension (AFX). Idea of the approach is to build a compact and photoreal-istic representation of a 3-D object or scene without using polyg-onal mesh. Instead, images accompanied by depth values for each pixel are used. This type of representation allows us to build and render novel views of objects and scene with an interactive rate. There are many different methods for the image-based rendering with depths, and the DIBR format is designed to efficiently rep-resent the information necessary for such methods. The main for-mats of the DIBR family are SimpleTexture (an image together with depth array), PointTexture (an image with multiple pixels along each line of sight), and OctreeImage (octree-like data structure to-gether with a set of images containing viewport parameters). In order to store and transmit the DIBR object, we develop a com-pression algorithm and bitstream format for OctreeImage repre-sentation. Index Terms—Compression, depth image, image-based rendering, image-based representation, MPEG-4 Animation Framework eXtension (AFX), octree, photorealistic representa-tion. I