[libcamera-devel] AE -- what is the goal was Re: Software gathering of image statistics for libcamera on Librem 5

[Pavel Machek]

Hi!

> > For millipixels, I was using:
> >
> > bright pixel is at least 200/255.
> >
> > too bright pixel is 240/255.
> >
> > I want not more than 8% too bright pixels, and as long as I have that,
> > I'd like at least 1% bright pixels.
> >
> > Is there consensus what the goal of AE should be?
> 
> There are a number of common techniques and features of such
> algorithms. though many vendors do their own thing and may even have
> "secret sauce" so I wouldn't go so far as to say there's any
> consensus. Increasingly sophisticated image analysis techniques like
> face detectors and machine learning are involved, and there is the
> whole question as to how to meter best for HDR too.
> 
> Raspberry Pi's implementation, for example, I would describe as
> straightforward and not worrying about any of these complications.
> It's documented here:
> https://datasheets.raspberrypi.com/camera/raspberry-pi-camera-guide.pdf
> (section 5.8). If you want something really simple you can do worse
> than use a trivial centre-weighted scheme.

So according to the docs rpi uses steps (first adjust exposure, then
gain, then exposure, then gain...) and does other clever stuff. Can
you point me when the actual code is? I probably should take a look
before reimplementing it...

Thanks for all the help,
								Pavel
-- 
People of Russia, stop Putin before his war on Ukraine escalates.
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