Re: mt9m111/mt9m131: kernel 3.8 issues.

javier Martin
2013-03-08T12:37:46Z

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.

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.

Regards.
--
Javier Martin
Vista Silicon S.L.
CDTUC - FASE C - Oficina S-345
Avda de los Castros s/n
39005- Santander. Cantabria. Spain
+34 942 25 32 60