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Infrared as watermark that can be detected by camera even in daylight

  1. Aug 12, 2012 #1
    Infrared works perfectly fine as a watermark on still images (infrared LEDs put at the back of the image) and even videos when the surrounding is dark.

    Is there a way to make it more noticeable even in broad daylight?

    And let's say, if my surrounding is dimmer and I want to obscure still-images without putting infrared LEDs at the back, but projecting the beam in front of the image, is there a way to make the infrared rays brighter? I tried using 4 flashlights/spotlights-style with 12 IrLEDs each but the image is still not blocked.
  2. jcsd
  3. Aug 12, 2012 #2


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    Staff: Mentor

    Very interesting. :wink:
    It sounds as though the IR is being largely absorbed by the canvas (or whatever), with little reflected? It might be possible to fiddle with angles, aiming the sources so that reflection would be towards where any pirate camera was likely to be positioned, but it might be a lost cause if reflection is diffuse and of low intensity. If you were dealing with paintings or photos, and were able to place them behind glass, investigate whether you can get better reflections off the glass surface. Or maybe there's a transparent coating that can be applied to glass to increase its reflection of IR?

    Good luck with your photographic enterprise.
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