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《计算机技术与发展》[ISSN:1006-6977/CN:61-1281/TN]

卷:

期数:

2013年01期

页码:

9-12

栏目:

智能、算法、系统工程

出版日期:

1900-01-01

文章信息/Info

Title:

Research on Algorithm of SFS for Multi-images Based on Phong Model

文章编号:

1673-629X（2013）01-0009-04

作者:

张宁; 杨磊

上海大学 机电工程与自动化学院

Author(s):

ZHANG Ning; YANG Lei

关键词:

Phong; 模型; 三维重建; Shape-From-Shading; 反射图方程

Keywords:

Phong model; 3-D shape reconstruction; Shape-From-Shading; reflection map equation

文献标志码:

A

摘要:

三维形状恢复是计算机视觉领域的热点之一.目前基于 Shape-From-Shading (SFS)的三维形状恢复方法采用描述漫反射的 Lambertian 模型,其数学形式简单,但重构结果与实际有较大差距.文中提出了一种基于 Phong 模型的多幅图像 SFS 三维形状恢复算法,该模型是一种典型的描述镜面反射的非 Lambertian 模型.首先由摄象机获得单目三幅不同光源位置的图像.然后求解由 Phong 模型描述的三个反射图方程,得到物体表面梯度向量.进一步利用灰度约束和梯度分量约束条件构造目标泛函,建立相应的 Eulor-Poision 方程并采用离散差分近似微分运算,得到物体表面三维形状恢复的迭代算法.提出的算法利用三幅图像的灰度值建立方程组,求得唯一确定的表面梯度数值,解决了传统单幅图像恢复三维形状的病态问题.同时基于非 Lambertian 模型建立反射图方程,可对含有镜面反射的表面进行三维形状恢复.最后通过仿真实验说明算法的有效性

Abstract:

Three-dimensional (3-D) shape reconstruction is one of the main problems in the field of computer vision. Most existing Shape-From-Shading (SFS) methods are based on the Lambertian reflectance model. The mathematical form of Lambertian reflectance model is simple,but reconstruction results of corresponding algorithms are relative poor compared with real 3-D shape of surfaces. New SFS algorithm based on the Phong model to reconstruct 3D shape of surface is proposed in this paper. The Phong model is a typical kind of non-Lambertian model to describe specular reflection. Three images with different light source directions are captured by camera first-ly. Following three reflectance map equations which are described by Phong model are established. Then the gradient vectors of the 3-D surface are calculated by solving the equations. The gray constraint and gradient component constraint conditions are used to construct tar-get function,and the corresponding Eulor-Poision equations are derived. Simultaneously,discrete difference is used to approximate differ-ential operation. New iterative 3-D shape reconstruction algorithm is proposed by the discrete difference equation. Three pixels values are used to solve certain gradient value in this method. So the ill-posed problem in traditional SFS which solves a single reflectance map e-quation can be avoided. At the same time,the algorithm solves the reflectance map equations which based on non-Lambertian model. So the proposed method can reconstruct 3D shape of surface containing specular reflection. At last,experimental results of 3-D reconstruction show that the proposed method is effective

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更新日期/Last Update: 1900-01-01