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Hello,
Our LED current looks like the following due to being from an offline regulator with no output capacitance.
Will CCTV cameras be able to film activity in the streets at night-time with this kind of heavily amplitude modulated lighting?
I heard about a digital camera that opens the shutter, then keeps it open while the electronic circuitry detects entering light. Finally sufficient image accumulates so that good quality is obtained. Then it closes the shutter.
Supposedly it can perform this process during a flashbulb event. However it's a good question whether a video camera can do the same thing. One spec to look for with video cameras is lux rating.
Are you mindful that rapid flashing lighting might trigger an epileptic episode in susceptible individuals?
My guess is you would see very strong strobing as the phase of the shutter (or it's equivalent in an electronic sensor) drifts by the pulses of light. It does depend on the camera scan rate though sop you might find significant differences from one camera to another.
thanks, we thought with a frame rate of one pic every millisecond youre going to catch pretty much everything?..say to identify a person who'd just committed a crime etc
Most CCTV cameras produce analog composite video because it's easy to carry along normal co-ax cables. The frame rate is 16.6 or 20mS, the same as 60Hz and 50Hz so the strobing risk is high. Bear in mind there are two methods of exposure control, one uses a mechanical iris driven from a small motor, the other adjusts the CCD capture time. The iris method has the advantage of better depth of field in bright light conditions and the capture method has the advantage of being purely electrical and hence cheaper. Given that you are talking about times when street lighting is operating and it is therefore fairly dark, the longer capture time in some cameras may average out the flicker to some extent.
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