Illuminate Your Video Inspections with a 30/60Hz Strobe Lamp

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Discussion Overview

The discussion revolves around the use of strobe lighting for video inspections, specifically the feasibility of using a strobe light triggered at 30Hz or 60Hz to illuminate a large scene while managing power constraints. Participants explore the implications of using pulsed versus continuous illumination in relation to different types of imaging sensors.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant suggests using a strobe light synced with the video camera's frame pulse to provide bright illumination for each image taken.
  • Another participant questions the efficiency of a strobe light compared to continuous illumination, noting that imaging arrays integrate incident radiation and suggesting further research into the readout processes of modern imaging arrays.
  • A participant mentions using an interline transfer CCD and proposes that operating a strobe at 30Hz could yield a 2x improvement in power per pixel, while also considering the need to illuminate the entire scene despite the camera's scanning limitations.
  • Concerns are raised about the necessity of continuous illumination to avoid dark bands in the image, given that sensors integrate energy over time.
  • Discussion includes the characteristics of CMOS arrays and interline CCDs, highlighting their different readout and integration processes.
  • A suggestion is made to use a flash unit synchronized with the camera's scan, proposing that a series of flash frames might be effective, while questioning the scanning speed of the camera.

Areas of Agreement / Disagreement

Participants express differing views on the effectiveness and efficiency of strobe lighting compared to continuous illumination, with no consensus reached on the best approach for the described video inspection scenario.

Contextual Notes

Participants acknowledge the complexity of imaging sensor behavior, including integration times and readout methods, which may influence the effectiveness of pulsed lighting. Specific assumptions about sensor operation and illumination needs remain unresolved.

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?
 
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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.
 
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.
 
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.
 
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.
 
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...

Irony = it's like goldy or silvery but made of iron
 
berkeman said:
BTW, I just read your footer -- killing me here...
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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