From: boyd@apt0.sao.arizona.edu   
      
   ggherold@gmail.com wrote:   
   > On Friday, January 31, 2014 6:18:23 AM UTC-5, Michael Balda wrote:   
   >> I'd like to use a pattern projector for computer vision tasks. The pattern   
   can be in the NIR range, should not repeat itself but doesn't need to be   
   described exactly, so random noise, speckle etc. should be fine. It would be   
   preferrable, if the    
   pattern can be restricted to a defined field of view instead of being   
   omni-directional and was stable over time. Of course there are several   
   different approaches but I would like to find one which is   
   >>   
   >> (a) cheap,   
   >>   
   >> (b) robust,   
   >>   
   >> (c) efficient (in terms of power consumption),   
   >>   
   >> (d) not too complex,   
   >>   
   >> (e) has good availability of components and   
   >>   
   >> (f) is monochromatic or has small bandwidth.   
   >>   
   >>   
   >>   
   >> Thanks in advance for any suggestions.   
   >   
   > Hmm, what are the different approaches?  I can only think of laser speckle   
   with a moving scattering source.  (So wiggle a ground glass diffusor back and   
   forth.. Well this is going to give a pattern that repeats.)   
   If the ground glass is left slightly loose in it's holder the chance of   
   showing  repeatability would be low. The OP didn't mention if the rate   
   of change of the pattern or direction of pattern motion or the   
   granularity scale of the pattern matters.  A laser diode can meets all   
   of the OP's requirements.  A single lens and a field stop can provide a   
   well defined field of view.   
      
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