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labpano / pilot-open-api

Open API for Pilot cameras
MIT License
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Clarifications needed - analog vs digital gain #4

Open creniq opened 3 years ago

creniq commented 3 years ago

Hello:

I would appreciate some clarification on the following API call:

com.pi.pano.ExposeTimeAdjustHelper.setValues(String fps, String exposedTime, String analogGain, String digitGain)

Judging by their names, I would expect that analog gain is applied before analog-to-digital conversion, and digital gain applied after. If that were the case, then analog gain would be better, because it will not amplify the quantization noise in the A/D conversion process. So why is there a digital gain control, then, if analog gain should always be preferred?

Secondly, if analog and digital gain are both set to PiProIso._200, should that be roughly equivalent to setting PiProIso._400 gain applied on either analog or digital gain (but not both)? But my experiment has shown that this is not the case, and I'm not understanding why.

Lastly, setting both gains to "auto" does not do what one would expect it to do - there is a LOT of image noise if both are set to "auto". Is there a bug with "auto" mode?

p.s. what is the purpose of 'fps' parameter in this call? I currently set it to something like "7" or "15", and I don't see any difference.

beforescaling commented 2 years ago

@creniq Hi, are you available for consulting with us?