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Is there a formula to determine that max flash rate countable by a video camera? I am thinking that any flash rate > # of fps is not practical. I get hung up on the fact that the shutter is open only a fraction of the amount of time required to produce a frame. 30fps is roughly 33.33ms. If the shutter is set for say 1/125 which is about 8ms or roughly 25% of the frame time. Does the shutter speed matter? I am thinking that unless they are sync'd the shutter could open at any point in the lamp flash ultimately making counting very difficult.

The application is just a general one. With today's high speed cameras (60fps or 120fps) can one reliably decide on the flash rate of a lamp. Think alarm panels, breathing monitors or heart rate monitors or the case of trying to determine duty cycle by visual means.

AeroClassics
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  • An issue is that the flashing light is possible flashing way faster than the fps of the camera. Is this a high speed camera? What is the source of the flashing light? – Eli Sadoff Jan 11 '17 at 18:35
  • please explain your motivation. there are usually much cheaper and better solutions to that problem. you might indeed have some problems, depending on shutter times and flash duration. – Piglet Jan 11 '17 at 19:45
  • Sorry. In my zeal for brevity I missed crucial information. I have edited the OP. – AeroClassics Jan 11 '17 at 19:59

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What you describe is related to the sampling problem. You can refer your problem to the Nyquist - Shannon theorem Given a certain frequency of acquisition (# of FPS) you can be sure of your counting (in every case, no matter of syncronization) if

"# of FPS" >= 2* flashing light frequency (in Hz)

Of course this is a general theoric rule, things can work in a quite different way (I am answering only regarding the number of FPS in a general case)

marcoresk
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