基于形变模型的物体建模与分析

Object Modeling and Analysis Based on Morphable Model: A Review

在物体建模领域内 ,传统的方法是建立三维线框模型上的纹理图像 .该方法计算复杂 ,数据冗余量大 ,显示效果真实性差 .近年来 ,在对同类物体 (尤其是人脸 )的建模研究中提出了形变模型 (m orphable m odel)的方法 .该方法数据冗余少 ,显示效果逼真 ,在低码率编码、分析识别、身份验证、重建等方面的应用中取得了良好效果 .文中回顾了近年来 morphable模型的研究、发展及应用情况 。

Object modeling has been an active research topic since it has wide applications such as recognition, virtual reality, computer animation, etc. These years morphable model has received considerable attention in modeling an object class (especially human faces) for its efficient data compression and realistic rendering. Its occurrence is inspired by a traditional rendering method in computer graphics, morphing, which generates new images as the interpolation of several given frames according to the correspondences between them. Similarly, morphable model is introduced to represent an object class with the linear combination of some typical instances of this class. This new model represents a new instance as a coefficient vector of the combination, so it is more efficient. Furthermore such a vector serves as a good feature for object recognition. With this model, object analysis can be converted to a common optimization problem, then more kinds of input data and mathematical tools are ready for utilization. At the same time, image rendering is much simplified. There are two key problems for working with this model. One is to find correspondences between different instances; the other is to apply proper constraints during combination in order to avoid generating false instance. Many kinds of application, such as very low bit-rate coding, personal identification, reconstruction, benefit from this model. The author reviews the morphable model and its development and applications, and presents the possible future research orientations.