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General / Re: Illumination artifact when texturing shiny surfaces
« on: July 07, 2018, 04:28:03 PM »
Great little rig 
Good to see someone do this, I played around with macro scanning a few years ago but never had the free time to put into it.
I would have thought that polarisation would help your project quite a bit, as a good polarised lighting rig combined with a polariser on the camera would give the ability to capture both diffuse and specular images.
Depending on the quality of the polarisers and position of the lights & camera you should in theory be able to elminate the specular reflection entirely by using cross polarisation.
If you have the abilty to "toggle" the polarisation angle between 0º and 90º, which as your subject does not move (not alive) you would not have to do very fast, perhaps just one polariser in front of the camera that can be rotated from 0º to 90º.
Then you lights only need one polarisation state ( i.e fixed linear polarising filters).
The issue I can see with all the above is that I suspect that your lighting dome and the position of the LED strips will change the angle of polarisation coming from the lights.
Ideally you would need a sphere of evenly spaced lights around the subject all pointing directly at it.
Having said all that I'm sure it's worth just putting a polarising filter in front of your camera and seeing if it helps fix the issue of the spyhole reflection.
Cheers,
mala
Good to see someone do this, I played around with macro scanning a few years ago but never had the free time to put into it.
I would have thought that polarisation would help your project quite a bit, as a good polarised lighting rig combined with a polariser on the camera would give the ability to capture both diffuse and specular images.
Depending on the quality of the polarisers and position of the lights & camera you should in theory be able to elminate the specular reflection entirely by using cross polarisation.
If you have the abilty to "toggle" the polarisation angle between 0º and 90º, which as your subject does not move (not alive) you would not have to do very fast, perhaps just one polariser in front of the camera that can be rotated from 0º to 90º.
Then you lights only need one polarisation state ( i.e fixed linear polarising filters).
The issue I can see with all the above is that I suspect that your lighting dome and the position of the LED strips will change the angle of polarisation coming from the lights.
Ideally you would need a sphere of evenly spaced lights around the subject all pointing directly at it.
Having said all that I'm sure it's worth just putting a polarising filter in front of your camera and seeing if it helps fix the issue of the spyhole reflection.
Cheers,
mala
