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Video rate strobe lamp?

  1. May 21, 2010 #1

    mgb_phys

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    I need to illuminate a scene for a video inspection.
    Unfortunately it's a big scene and I don't have unlimited power.

    I though of using a strobe light triggered at 30Hz (or ideally 60Hz) and synced from the frame pulse of the video camera - so I get a bright pulse of light as each image is taken.

    Anyone know of a strobe that can do 30/60Hz rate?
     
  2. jcsd
  3. May 21, 2010 #2

    berkeman

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    I'm not sure a strobe of comparable power to continuous illumination will be any more efficient. The imaging array is integrating the incident radiation (I think), so whether it is continuous or pulsed shouldn't make much of a difference.

    I guess I'd need to research how the latest imaging arrays are read out, though. If the readout duty cycle isn't real narrow, then you could pick up some efficiency, probably ratioed to that duty cycle.
     
  4. May 21, 2010 #3

    mgb_phys

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    It's an interline transfer CCD, so I thought if I ran a strobe at 30Hz and only recorded one field I at least got a 2x improvement in power/pixel.
    Worse case I can slow it down even more and throw away more fields.

    The problem is that the camera is scanning over a scene, but I can't move the illumination so I'm stuck with trying to illuminate everything while building up an overall view of the scene.
     
  5. May 21, 2010 #4

    sophiecentaur

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    You may be reading the sensors in short bursts but they need to integrate the received energy over a reasonable time and I think that even digital image arrays are scanned - so you will need illumination all the time or you will get dark bands on your TV picture.
     
  6. May 21, 2010 #5

    mgb_phys

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    CMOS arrays are scanned, especially on slow frame rate webcams.
    Interline CCDs transfer the current image almost instantly (few us) to the storage register and read it out while integrating the next field.
     
  7. May 21, 2010 #6

    berkeman

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    Can you maybe charge up a flash unit, and periodically shoot a flash picture that is sync'ed to the scan of the camera? It sounds like you are going to store and process the images anyway, so maybe just having a series of flash frames will work? How quickly is the camera scanning? Could you attach a photo flash unit to the camera body, so you get that increase in efficiency as well?

    BTW, I just read your footer -- killing me here...

     
  8. May 21, 2010 #7

    mgb_phys

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    I had one warning about irony, but some people seemed to still need an explanation

    Not original though
    AY-rVVRZoC8[/youtube]
     
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