Re: Software-only image processing for Intel "complex" cameras

[Pavel Machek <pavel@ucw.cz>]

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Hi!

> > On Nokia N900, I have similar problems as Intel IPU3 hardware.
> >
> > Meeting notes say that pure software implementation is not fast
> > enough, but that it may be useful for debugging. It would be also
> > useful for me on N900, and probably useful for processing "raw" images
> > from digital cameras.
> >
> > There is sensor part, and memory-to-memory part, right? What is
> > the format of data from the sensor part? What operations would be
> > expensive on the CPU? If we did everthing on the CPU, what would be
> > maximum resolution where we could still manage it in real time?
> 
> We can still use the memory-to-memory part (IMGU), even without 3A. It
> would just do demosaicing at default parameters and give us a YUV
> (NV12) frame. We could use some software component to analyze the YUV
> output and adjust sensor parameters accordingly. Possibly the part we
> already have in libv4l2 could just work?

As soon as you get YUV, yes, libv4l2 should be able to work with that.

OTOH using the memory-to-memory part is going to be tricky. What
format is the data before demosaicing? Something common like BGGR10?

> The expensive operation would be analyzing the frame itself. I suppose
> you need to build some histogram representing brightness and white
> balance of the frame and then infer necessary sensor adjustments from
> that.

That does not really have to be expensive. You can sample ... say
10000 pixels from the image, and get good-enough data for 3A.

> > Would it be possible to get access to machine with IPU3, or would
> > there be someone willing to test libv4l2 patches?
> 
> I should be able to help with some basic testing, preferably limited
> to command line tools (but I might be able to create a test
> environment for X11 tools if really necessary).

Could you just compile libv4l2 with sdlcam demo on the target, and
then ssh -X there from some sort of reasonable system?

Best regards,
								Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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