Average surface roughness evaluation using 3-source photometric stereo technique
نویسندگان
چکیده
This paper presents a technique for measuring surface roughness (Ra), using photometric stereo method. The method utilizes three or more images of the measured surface from the same viewpoint, taken sequentially under different illumination conditions. The scenes captured by the camera were reconstructed by the least square method to obtain surface normal from surface topography. Three-dimensional surface textural patterns were recovered from those surface normal. The system was validated with five standard surface roughness specimens. The Ra calculated from the recovered surface was compared with the values measured from contacting roughness measurement (stylus instrument). The best coefficient of the slant angles can also be determined through the linear regression. The experimental results indicate that the technique can be applied to well recover standard surface roughness.
منابع مشابه
Average Surface Roughness Measurement Using Photometric Stereo Method
This paper presents a technique for measuring surface roughness (Ra), using photometric stereo method. The method utilizes three or more images of the measured surface from the same view point, taken sequentially under different illumination conditions. The scenes captured by the camera were reconstructed by the least square method to obtain surface normal from surface topography. Three-dimensi...
متن کامل3D In-Vivo Measurement of Skin Topography Using Photometric Stereo
Increased demand for treatment of skin wrinkles has led to a proliferation of different pharmaceutical and surgical treatment methods. However there still remains a lack of quantitative, objective, easily utilizable and reproducible wrinkle classification system by which these treatments can be studied and compared. We propose the use of a novel photometric stereo based technique as a potential...
متن کاملExtracting the shape and roughness of specular lobe objects using four light photometric stereo
Two important aspects of part inspection are the measurement of surface shape and surface roughness. We propose a noncontact method of measuring surface shape and surface roughness. The method, which we call “four light photometric stereo”, uses four lights which sequentially iUuminate the object under inspection, and a video camera for taking images of the object. Conceptually, the problem we ...
متن کاملSurface Reconstruction Using Polarization and Photometric Stereo
This paper presents a novel shape recovery technique that combines photometric stereo with polarization information. First, a set of ambiguous surface normals are estimated from polarization data. This is achieved using Fresnel theory to interpret the polarization patterns of light reflected from dielectric surfaces. The process is repeated using three different known light source positions. Ph...
متن کاملThe 4-Source Photometric Stereo Technique for Three-Dimensional Surfaces in the Presence of Highlights and Shadows
We present an algorithm for separating the local gradient information and Lambertian color by using 4-source color photometric stereo in the presence of highlights and shadows. We assume that the surface reflectance can be approximated by the sum of a Lambertian and a specular component. The conventional photometric method is generalized for color images. Shadows and highlights in the input ima...
متن کامل