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user924
user924

If you choose synchronous detection, then you can simplify solution. Then you may want to choose LEDs as narrow angled as you can withing any part of visible spectrum.

Synchronous detection is the way to detect a signal which may be lower than background noise. Imagine taking shot with camera before LEDs are up. Then turn LEDs on and take another picture with exactly same conditions. Subtract arrays of pixelspixel values of 2 frames from each other and look at the remainder. It will contain perfect difference of what was lit by LEDs. In your setup the DIFF picture will contain exactly retroreflectors (cataphote) only. Because the rest of the scenery got no significant increase in brightness.

While you debug the solution it will be obvious that power of LEDs can be reduced to some very low level, but only experiments will tell. I estimate that you will not need any super-powerful diodes. Some ordinary white LEDs with very acurate lens will do.

If you choose synchronous detection, then you can simplify solution. Then you may want to choose LEDs as narrow angled as you can withing any part of visible spectrum.

Synchronous detection is the way to detect a signal which may be lower than background noise. Imagine taking shot with camera before LEDs are up. Then turn LEDs on and take another picture with exactly same conditions. Subtract arrays of pixels and look at the remainder. It will contain perfect difference of what was lit by LEDs. In your setup the DIFF picture will contain exactly retroreflectors (cataphote) only.

While you debug the solution it will be obvious that power of LEDs can be reduced to some very low level, but only experiments will tell. I estimate that you will not need any super-powerful diodes. Some ordinary white LEDs with very acurate lens will do.

If you choose synchronous detection, then you can simplify solution. Then you may want to choose LEDs as narrow angled as you can withing any part of visible spectrum.

Synchronous detection is the way to detect a signal which may be lower than background noise. Imagine taking shot with camera before LEDs are up. Then turn LEDs on and take another picture with exactly same conditions. Subtract arrays of pixel values of 2 frames from each other and look at the remainder. It will contain perfect difference of what was lit by LEDs. In your setup the DIFF picture will contain exactly retroreflectors (cataphote) only. Because the rest of the scenery got no significant increase in brightness.

While you debug the solution it will be obvious that power of LEDs can be reduced to some very low level, but only experiments will tell. I estimate that you will not need any super-powerful diodes. Some ordinary white LEDs with very acurate lens will do.

Source Link
user924
user924

If you choose synchronous detection, then you can simplify solution. Then you may want to choose LEDs as narrow angled as you can withing any part of visible spectrum.

Synchronous detection is the way to detect a signal which may be lower than background noise. Imagine taking shot with camera before LEDs are up. Then turn LEDs on and take another picture with exactly same conditions. Subtract arrays of pixels and look at the remainder. It will contain perfect difference of what was lit by LEDs. In your setup the DIFF picture will contain exactly retroreflectors (cataphote) only.

While you debug the solution it will be obvious that power of LEDs can be reduced to some very low level, but only experiments will tell. I estimate that you will not need any super-powerful diodes. Some ordinary white LEDs with very acurate lens will do.