Using a picamera, what is the best latency one can achieve from a real world event like an led lighting up and the Pi/MCU 'knowing' it has occured(by extracting image data)?
I would also be interested in all the parameters being involved, especially those the user has control over like shutter speed.
The docs state a maximum FPS of 90, resulting in a frame time of 11ms. But that does not guarantee an actual response within that timeframe. I couldn't find any worthy mention of latency in said docs.
Setting up an experiment
The best experiment I can think of consists of
- pi + cam
- an LED
- an oscilloscope
The oscilloscope is hooked up to the led as well as any digital GPIO of the pi, measuring the time between those 2 changing level.
The software on the pi shouldn't perform any more processing than let's say checking a single pixel in the center of the picture for being brighter than a dumb threshold like 200 and pulling the GPIO pin high, if it is. This way, processing power won't matter much.