On Radiance materials - Examples

Examples

The classical metal model of Radiance was fitted to the BRTF data using standard Levenberg-Marqwardt fitting methods. Gray reflectance (R=G=B for the first three parameters of the model) was assumed. Light source was a XBO short arc lamp.
The incident angle theta_in, phi_in is encoded into the file name. For pab-xenon-aluA-st1:+15+0.mpc: theta_in=15^o, phi_in=0^o .
The following tables give the measured BRTF, their visualization, the parameters RGB, specularity and roughness, and the error (sum of weighted, squared difference between model and data at measured positions).
Visualizations were done using mountain, a custom written program for displaying BRTF measurements done by the above mentioned gonio-photometer. The BRTF of a perfectly diffuse material would show as flat surface. For high values, the measurements are done at finer angular resolution (see my Phd for a discussion on measurement technique). The small gaps in the data are due to self shadowing of the ISE-FhG gonio-photometer.

Sand blasted aluminium sheet, metal model

Aluminium sheet blasted with small glass spheres. More isotropic than raw aluminium sheet, but still showing asymmetric scattering

data file	visualization		Radiance metal model
	orthogonal	oblique	RGB,spec,rough fit				visualization
			R,G,B	spec.	rough.	error	model	difference
pab-xenon-aluA-st1-b:raw/+0+0.mpc			0.624	0.706	0.437	20
pab-xenon-aluA-st1-b:raw/+15+0.mpc			0.857	1	0.497	2.8
pab-xenon-aluA-st1-b:raw/+30+0.mpc			0.937	0.981	0.479	6.7
pab-xenon-aluA-st1-b:raw/+45+0.mpc			1.06	0.999	0.45	21
pab-xenon-aluA-st1-b:raw/+60+0.mpc			1.46	1.15	0.436	2e+02

work-in-progress. Please bear with us while the rest is under construction. Thanks

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Last modified Monday September 02, 2002