Extracting the shape and roughness of specular lobe objects using four light photometric stereo

A noncontact method of measuring surface shape and surface roughness for part inspection is proposed. The method, called four-light photometric stereo, uses four lights that sequentially illuminate the object under inspection, and a video camera that takes images of the object. Conceptually, the problem has three parts: shape extraction, pixel segmentation, and roughness extraction. The shape information is produced directly by three-light and four-light photometric stereo methods. After shape information is obtained, statistical segmentation techniques can be applied to determine which pixels are specular and which are nonspecular. Then the specular pixels and shape information can be used, in conjunction with a simplified Torrance-Sparrow reflectance model, to determine the surface roughness. The method has successfully been applied to a number of synthetic and real objects.<<ETX>>

[1]  E. North Coleman,et al.  Obtaining 3-dimensional shape of textured and specular surfaces using four-source photometry , 1982, Comput. Graph. Image Process..

[2]  Robert J. Woodham,et al.  Reflectance map techniques for analyzing surface defects in metal castings , 1978 .

[3]  Takeo Kanade,et al.  Determining shape and reflectance of hybrid surfaces by photometric sampling , 1989, IEEE Trans. Robotics Autom..

[4]  Lawrence B. Wolff.  Shape from polarization images , 1992 .

[5]  L. B. Wolff.  Spectral and polarization stereo methods using a single light source , 1992 .

[6]  Thomas O. Binford,et al.  Local shape from specularity , 1988, Comput. Vis. Graph. Image Process..

[7]  K. Torrance,et al.  Theory for off-specular reflection from roughened surfaces , 1967 .

[8]  Takeo Kanade,et al.  Surface Reflection: Physical and Geometrical Perspectives , 1989, IEEE Trans. Pattern Anal. Mach. Intell..

[9]  Kosuke Sato,et al.  Determining reflectance parameters using range and brightness images , 1990, [1990] Proceedings Third International Conference on Computer Vision.

[10]  Berthold K. P. Horn,et al.  Determining Shape and Reflectance Using Multiple Images , 1978 .

[11]  Andrew Blake,et al.  Detecting Specular Reflections Using Lambertian Constraints , 1988, [1988 Proceedings] Second International Conference on Computer Vision.

[12]  Katsushi Ikeuchi,et al.  Determining Surface Orientations of Specular Surfaces by Using the Photometric Stereo Method , 1981, IEEE Transactions on Pattern Analysis and Machine Intelligence.

[13]  Lee E. Weiss,et al.  Specular surface inspection using structured highlight and Gaussian images , 1990, IEEE Trans. Robotics Autom..

[14]  P. R. Bevington,et al.  Data Reduction and Error Analysis for the Physical Sciences , 1969 .