Interesting question, but is-it the right one ?

under this proposition, we have the idea of support uniformity reflecting a uniform colour kepted by BRDF, avoiding so the multi-scale texture effects. In this sense, BRDF offers lot of information about the average energy reflected in a certain direction for a certain wavelength, but with the restriction of  uniform world.

Recent advances in multi and hyperspectral texture features, and the ability to link these texture features to perceptual texture features offers perhaps new alternatives to such questions. Nevertheless, they don't embed for the moment the notion of directionnality in the viewing condition.

Best regards,

Noël

Thank you Noël and Jacopo.

Noel : I agree about the restrictions of the notion of BRDF. But, it is still a very comprehensive parameter, that would need to be coupled with texture to give a full understanding of the reflection of an incident wave of an arbitrary surface. I am more interested in measuring BRDF without using conventional equipments (complex mechanical goniometers)...

Jacapo : the idea is to have a device that would reflect or transmit an incoherent light beam (emitted by an LED for instance) with a given angular distribution (a single lobe or a combination of several lobes), without mechanical equipment (no scanner, no moving prism, no variable lens, etc.). Ideally, the light would be broadband in the visible range (white light) but coloured LED would be fine too (5 to 10 nm wide).

The concept would be somehow similar to a controlable light diffuser. I have never used SLM so far. Are you aware of such applications of SLM ?

Christophe