Re: mt9m111/mt9m131: kernel 3.8 issues.

Benoît Thébaudeau
2013-03-08T13:22:53Z

Hi Javier,

On Friday, March 8, 2013 1:37:38 PM, Javier Martin wrote:
> Hi Benoît,
>
> On 8 March 2013 12:53, Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
> wrote:
> >
> >> Regarding 3, you say it works nicely for you in kernel 3.4.5. I've
> >> migrated my code to that version but I still get colours that lack
> >> enough intensity.
> >> This is a snapshot "a" taken with my mobile which is much more similar
> >> to what I can really see with my eyes:
> >> http://img96.imageshack.us/img96/1451/20130307171334.jpg
> >>
> >> This is a similar snapshot "b" taken with mt9m131 in my board. It
> >> shows that colours tend to be dull and darker, specially green:
> >> http://img703.imageshack.us/img703/6025/testgo.jpg
> >>
> >> Are the snapshots you take with your HW more similar to "a" or to
> >> "b"? Perhaps I am being too picky with the image quality and this is
> >> all what mt9m131 can do?
> >
> > I fear that my captures are closer to "b". Your description of "3" was
> > giving
> > the impression of flashy colors. But the impression that this sensor gives
> > me is
> > rather a superimposed gray film. This effect is more or less visible
> > depending
> > on the lighting conditions, but it never seems to produce high quality
> > colors.
>
> Yes, yours is probably is the best description for the image quality
> this sensor provides with the current settings.
> Well, this is a bit disappointing. Let's see if some other user has a
> similar experience with it or comes up with a way to improve it.
>
> I've tested several things such as disabling auto white balance and
> auto exposure and try to manually change colour gains but it seems the
> sensor simply ignores the latter.
>
> There is an evaluation board from Aptina
> (http://www.digikey.com/product-detail/es/MT9M131C12STCH%20ES/557-1251-ND/1643271)
> but, unfortunately, I don't have one of these available. It could be
> very useful to test the sensor with this board with the configuration
> Aptina recommends and see whether the "grey layer effect" still
> persists.

It is perhaps also possible to find their recommended register settings
somewhere without having this evaluation board.

> I will try to contact Aptina's technical support but, according to my
> previous experience, there is no guarantee we get a clarifying answer.
> I'll keep you updated nevertheless.

Thanks.

Best regards,
Benoît