[libcamera-devel] Software gathering of image statistics for libcamera on Librem 5

[Pavel Machek]

Hi!

> > I'm playing with camera on Librem 5. So far I added af/ae/awb support
> > to millipixels done completely in software, but I guess libcamera
> > would be more suitable place for it. If you have some hints/example
> > where to look at, it would be nice.
> 
> The area you are looking at is essentially doing the role of a software
> based ISP processor. It would be a component that a pipeline handler
> could choose to instantiate, to support any algorithms that use the data
> you produce. It can be difficult to produce 'generic' data that any
> > IPA

I don't need full ISP. I just need to gather enough statistics.

> But how that would fit in the libcamera design would need further
> consideration ... falling back to software ISP ... should really be
> avoided ... but perhaps there's benefits for early bring up - or simply
> being able to manage a simple way of getting AWB/AE for raw streams,
> without an ISP (as we have on the RKISP1), so I think it has some
> value.

..to do AWB/AE/AF. If I wanted to, I'd only need to access 200 pixels
or so.

> Ideally - we shouldn't rely on the CPU where possible though, and that's
> why several people have been looking at a GPU/OpenGL based option. I
> could imagine a software fallback would be a part of that pairing of
> SoftwareISP component.

Due to small ammount of computation, this is not really job for GPU.

Thanks for rkisp pointer. I'm quite confused by that code, not knowing
much about rkisp. Does it have some special support in hardware, like
providing one stream of frames for application and second for
statistics gathering?

For Librem 5 (and possibly PinePhone and similar), I'd like to snoop
on frames provided to the application, and set up exposure
accordingly. But I don't see any code in libcamera accessing image
data.

Closest I could get is Image class (src/apps/common/image.h) used by
file sinks in cam application. Would it be acceptable to move that
into libcamera and use it to peek at the pixels?

Best regards,
								Pavel
-- 
People of Russia, stop Putin before his war on Ukraine escalates.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 195 bytes
Desc: not available
URL: <https://lists.libcamera.org/pipermail/libcamera-devel/attachments/20221209/c9ebaf93/attachment.sig>