Estimating Illumination Parameters Using Spherical Harmonics Coefficients in Frequency Space  

作　　者：谢峰 陶霖密 徐光祐 

机构地区：[1]Key Laboratory of Pervasive Computing (Tsinghua University) of the Ministry of Education, Department of Computer Science and Technology, Tsinghua University

出　　处：《Tsinghua Science and Technology》2007年第1期44-50,共7页清华大学学报（自然科学版（英文版）

基　　金：the National Natural Science Foundation of China (No. 60273005)

摘　　要：An algorithm is presented for estimating the direction and strength of point light with the strength of ambient illumination. Existing approaches evaluate these illumination parameters directly in the high dimensional image space, while we estimate the parameters in two steps： first by projecting the image to an orthogonal linear subspace based on spherical harmonic basis functions and then by calculating the parameters in the low dimensional subspace. The test results using the CMU PIE database and Yale Database B show the stability and effectiveness of the method. The resulting illumination information can be used to synthesize more realistic relighting images and to recognize objects under variable illumination.An algorithm is presented for estimating the direction and strength of point light with the strength of ambient illumination. Existing approaches evaluate these illumination parameters directly in the high dimensional image space, while we estimate the parameters in two steps： first by projecting the image to an orthogonal linear subspace based on spherical harmonic basis functions and then by calculating the parameters in the low dimensional subspace. The test results using the CMU PIE database and Yale Database B show the stability and effectiveness of the method. The resulting illumination information can be used to synthesize more realistic relighting images and to recognize objects under variable illumination.

关 键 词：illumination parameters estimation spherical harmonic image relighting 

分 类 号：TM923[电气工程—电力电子与电力传动]