Fast algebra algorithm of shape-from-shading with specular reflectance  

作　　者：杨磊 韩九强 

机构地区：[1]School of Electronics and Information Engineering Xi'an Jiaotong University

出　　处：《Chinese Optics Letters》2007年第4期204-207,共4页中国光学快报（英文版）

基　　金：This work was supported by the National Natural Science Foundation of China under Grant No.60502021.

摘　　要：Shape-from-shading （SFS） is to reconstruct three-dimensional （3D） shape from a single gray image, which is an important problem in computer vision. We propose a novel SFS method based on hybrid reflection model which contains both diffuse reflectance and specular reflectance. The intensity gradient of image is in the direction that the shape of surface changes most, so we use directional derivative of the reflectance map as parts of objective function. When discrete characteristic of digital images is considered, finite difference approximates differential operator. So the reflectance map equation described by a partial differential equation （PDE） turns into an algebra equation about the unknown surface height correspondingly. Using iterative numeric computation, a new SFS method is gained. Experiments on synthesis and real images show that the proposed SFS method is accurate and fast.Shape-from-shading （SFS） is to reconstruct three-dimensional （3D） shape from a single gray image, which is an important problem in computer vision. We propose a novel SFS method based on hybrid reflection model which contains both diffuse reflectance and specular reflectance. The intensity gradient of image is in the direction that the shape of surface changes most, so we use directional derivative of the reflectance map as parts of objective function. When discrete characteristic of digital images is considered, finite difference approximates differential operator. So the reflectance map equation described by a partial differential equation （PDE） turns into an algebra equation about the unknown surface height correspondingly. Using iterative numeric computation, a new SFS method is gained. Experiments on synthesis and real images show that the proposed SFS method is accurate and fast.

关 键 词：Algorithms CALCULATIONS Computer vision Mathematical operators Partial differential equations REFLECTION Three dimensional 

分 类 号：TP391.41[自动化与计算机技术—计算机应用技术]