This is a machine vision/imaging sort of a problem where we wish to detect dry areas on mostly wet surface. In order to reliably do that we'd like to optimize the imaging side of it. At the moment we're going for making use of the specular reflections of the wet areas. Mirroring the camera and the light angles we can usually have the wet parts appear much brighter giving us an indication, however, the material surface roughness and color varies a lot giving us sometimes unreliable results.

Now, we're looking to use all kinds of tricks to maximize the effect of separating the specular reflections from the diffuse ones. I'm reading posts in this community and I'm seeing you're very good with light manipulation and whatnot. Would you have any neat tips for my problem?

Here are some that we have in mind:

  • Mirrored angle between light (white LED) and camera (monochrome sensor)
  • Linear polarizer filter in an angle where the partially polarized specular reflection passes through
  • Two images with opposite angles of polarizing filters, compare the images to determine the specular reflection

All ideas are welcome and much appreciated.

  • 4
    I'm voting to close this question as off-topic because it is about machine vision in a context not likely to be relevant to photography. – mattdm Feb 26 '15 at 13:38
  • 2
    Yes, it is relevant becouse vekkuli is asking for advice on how to take the images or analize them. – Rafael Feb 26 '15 at 13:55
  • Yes i'd agree its about obtaining an image, not the processing of, So i'd say it's on topic - although not "arty" enough for some possibly – Digital Lightcraft Feb 26 '15 at 14:35
  • I can see how it is sort of off-topic, though, I do want to emphasize that anything outside the photographic aspect of it should be excluded. The post that encouraged me to come here was in fact this: photo.stackexchange.com/questions/26067/… – vekkuli Feb 26 '15 at 14:36
  • Can you give us more info on the surface texture(s) you are looking at? – Digital Lightcraft Feb 26 '15 at 14:36

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