混合反射表面下SFS三维形貌重建方法研究  

Study of SFS-Based 3D Shape Recovery Approach for Hybrid Reflectance Surfaces

作　　者：王国珲[1] 吴二星 WANG Guohui;WU Erxing(School of Optoelectronic Engineering,Xi＇ an Technological University,Xi＇an 710021,China)

机构地区：[1]西安工业大学光电工程学院,西安710021

出　　处：《西安工业大学学报》2018年第4期329-336,共8页Journal of Xi’an Technological University

基　　金：国家自然科学基金(61102144);西安工业大学陕西省光电测试与仪器技术重点实验室开放基金(2016SZS-60-1)

摘　　要：针对混合反射表面SFS重建方法中图像辐照度方程难以求解的问题,文中提出了基于Schlick模型的SFS三维形貌重建方法.在正交投影且光源与摄像机方向一致情况下,构建了基于Blinn反射模型的混合反射表面下图像明暗变化与物体三维形貌相对应的偏微分辐照度方程,使用Schlick模型代替原Blinn模型中的镜面反射成分,将辐照度方程转化为关于三维形貌梯度的二次方程,求解此方程可获得Eikonal类偏微分方程,利用一阶和高阶fast sweeping方法对上述方程的解进行了逼近.结果表明:一阶和高阶方法均能简便地求解混合反射表面下建立的SFS偏微分辐照度方程,后者比前者可获得更高的三维重建精度,高阶方法的高度MAE和RMSE误差比一阶方法降低了大约38%.It is difficult to solve the image irradiance equation in the shape from shading （SFS） recovery approach for hybrid reflectance surfaces. To resolve this problem, the paper proposes a SFS-based 3D shape recovery approach using Schlick model. With the orthographic projection and the light source＇s direction coinciding with the camera, the partial differential irradiance equation, which depicts the relationship between image shading variations and the 3D shape, is constructed for hybrid reflectance surfaces based on the Blinn reflection model. The equation then is transformed into a quadratic equation in the variable of 3D shape gradient with the specular reflection of Blinn model replaced with Schlick model. The Eikonal partial differential equation is obtained by solving the quadratic equation. Its solution is approximated by using first-order and high-order fast sweeping methods. The results show that the methods can easily solve the SFS partial differential irradiance equation of hybrid reflectance surfaces and that the high-order method can get higher 3D recovery accuracy. MAE and RMSE of the height by the high-order method are reduced by about 38~/oo compared with the first-order method.

关 键 词：SFS 混合反射表面 三维形貌重建 偏微分辐照度方程 FAST sweeping方法 

分 类 号：TP391[自动化与计算机技术—计算机应用技术]