Title :
Spectral gradient: a material descriptor invariant to geometry and incident illumination
Author :
Angelopoulou, Elli ; Lee, Sang W. ; Bajcsy, Ruzena
Author_Institution :
GRASP Lab., Pennsylvania Univ., Philadelphia, PA, USA
Abstract :
The light reflected from a surface depends on the scene geometry, the incident illumination and the surface material. A novel methodology is presented which extracts reflectivity information of the various materials in the scene independent of incident light and scene geometry. A scene is captured under different narrow-band color filters and the spectral derivatives of the scene are computed. The resulting spectral derivatives form a spectral gradient at each pixel. This spectral gradient is a material descriptor which is invariant to scene geometry and incident illumination for smooth diffuse surfaces. Spectral gradients can discriminate among smooth dielectrics with different reflectance properties independent of viewing conditions
Keywords :
computer vision; reflectivity; computer vision; incident illumination; material descriptor; reflectivity; scene geometry; Computer vision; Filters; Geometry; Layout; Lighting; Narrowband; Photometry; Reflectivity; Research initiatives; Surface waves;
Conference_Titel :
Computer Vision, 1999. The Proceedings of the Seventh IEEE International Conference on
Conference_Location :
Kerkyra
Print_ISBN :
0-7695-0164-8
DOI :
10.1109/ICCV.1999.790312