TY - GEN
T1 - Irradiation orientation from obliquely viewed texture
AU - Pont, Sylvia C.
AU - Koenderink, Jan J.
N1 - Niet-TUD publicatie
PY - 2005
Y1 - 2005
N2 - We studied image texture due to the shading of corrugated (3D textured) surfaces, which are Lambertian on the micro scale. Our theory applies to physically canonical cases of isotropic Gaussian random surfaces, under collimated illumination. In this investigation we analyze effects of oblique viewing, extending our theory which applied to normal viewing conditions only [5]. The theory for normal views predicts the structure tensors from either the gradient or the Hessian of the image intensity and allows for inferences of the orientation of irradiation of the surface. Even for surfaces that are not at all Gaussian, the BRDF [10] far from Lambertian, with vignetting and multiple scattering present, such inferences of the orientation of irradiation were accurate up to a few degrees. In this paper we derive predictions for oblique viewing conditions, for which the inferences of the irradiation orientation will deviate from the veridical value in a systematic manner, depending on the viewing and illumination directions. Theoretical predictions are compared with empirical data, for rendered and for real rough surfaces, and found to be in good agreement. We discuss issues of scale selection and robustness.
AB - We studied image texture due to the shading of corrugated (3D textured) surfaces, which are Lambertian on the micro scale. Our theory applies to physically canonical cases of isotropic Gaussian random surfaces, under collimated illumination. In this investigation we analyze effects of oblique viewing, extending our theory which applied to normal viewing conditions only [5]. The theory for normal views predicts the structure tensors from either the gradient or the Hessian of the image intensity and allows for inferences of the orientation of irradiation of the surface. Even for surfaces that are not at all Gaussian, the BRDF [10] far from Lambertian, with vignetting and multiple scattering present, such inferences of the orientation of irradiation were accurate up to a few degrees. In this paper we derive predictions for oblique viewing conditions, for which the inferences of the irradiation orientation will deviate from the veridical value in a systematic manner, depending on the viewing and illumination directions. Theoretical predictions are compared with empirical data, for rendered and for real rough surfaces, and found to be in good agreement. We discuss issues of scale selection and robustness.
UR - http://www.scopus.com/inward/record.url?scp=33646581048&partnerID=8YFLogxK
U2 - 10.1007/11577812_18
DO - 10.1007/11577812_18
M3 - Conference contribution
AN - SCOPUS:33646581048
SN - 3540298363
SN - 9783540298366
VL - 3753 LNCS
T3 - Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
SP - 205
EP - 210
BT - Deep Structure, Singularities, and Computer Vision - First International Workshop, DSSCV 2005, Revised Selected Papers
T2 - 1st International Workshop on Deep Structure, Singularities, and Computer Vision, DSSCV 2005
Y2 - 9 June 2005 through 10 June 2005
ER -