In this image we can see that some light intensity is lost from the reflection. How is this accounted for in the mathematical models we examined in the rest of this lecture?
tanjeffreyz
Please correct me if I'm wrong, but wouldn't the BRDF account for this loss in intensity? My current interpretation of BRDFs is that they "spread out" the energy from a light source based on the properties (matte, glossy, etc) of the material. But I think in this case, it would be the BRDFs of the water particles doing the diffusing instead of the BRDF of the block?
william-fei
I assumed perfect specular reflection also meant that the intensity would stay the same. But in this example, the light source loses intensity after hitting the block. Does "perfect" reflection only refer to angle?
sZwX74
I think in this case perfectly specular reflection just implies that all the light reflected from the surface is transmitted at the angle of incidence, and that there is zero diffusion behavior happening. The intensity of the light reflected is governed by the reflectivity of the material, which is a different factor. Not all the light entering a surface has to leave it; for example, consider the black surface in the image absorbs some of the light as heat, so even though its reflection is perfectly specular in that the laser bounces its entire ray at that exact angle and doesn't diffuse away, the some of the intensity of the light has been converted into heat energy.
In this image we can see that some light intensity is lost from the reflection. How is this accounted for in the mathematical models we examined in the rest of this lecture?
Please correct me if I'm wrong, but wouldn't the BRDF account for this loss in intensity? My current interpretation of BRDFs is that they "spread out" the energy from a light source based on the properties (matte, glossy, etc) of the material. But I think in this case, it would be the BRDFs of the water particles doing the diffusing instead of the BRDF of the block?
I assumed perfect specular reflection also meant that the intensity would stay the same. But in this example, the light source loses intensity after hitting the block. Does "perfect" reflection only refer to angle?
I think in this case perfectly specular reflection just implies that all the light reflected from the surface is transmitted at the angle of incidence, and that there is zero diffusion behavior happening. The intensity of the light reflected is governed by the reflectivity of the material, which is a different factor. Not all the light entering a surface has to leave it; for example, consider the black surface in the image absorbs some of the light as heat, so even though its reflection is perfectly specular in that the laser bounces its entire ray at that exact angle and doesn't diffuse away, the some of the intensity of the light has been converted into heat energy.