Simplification of 3D scanned head data for use in real-time model-based coding systems

In this paper we present an algorithm for reducing a set of high-density scanned range data to a simplified polygonal mesh. Of major interest is the application of this algorithm to Cyberware 3D range data of human heads to produce simple yet accurate wireframe approximations for use in model based video coding systems. The objective is to decimate the range data while maintaining acceptable levels of resolution over critical sections of the face, such as areas of high curvature (noise, mouth) and sections with fine detail (eyes). Areas such as foreheads and cheeks which are relatively smooth are represented with lower geometric detail. The algorithm employs a quadtree-based representation of the range data and subsequent mergings of the leaf nodes are determined by a multi-variable cost function. Factors taken into account in creating the cost function are fitting error, polygon aspect ratios, and improvement in mesh simplification. This method has been tested on a database of Cyberware head data and the results are presented at the end of the paper. Experiments show that the algorithm provides considerable data reduction and the resulting simplified wireframe is accurate enough for use in a real-time model based coding system.