Re: OMAP3 ISP previewer Y10 to UYVY conversion

Chris Whittenburg
2015-03-25T14:12:57Z

Hi Sakari,

Thanks for the reply.

On Tue, Mar 24, 2015 at 6:51 PM, Sakari Ailus <sakari.ailus@iki.fi> wrote:
> Do you know if the sensor has black level correction enabled? It appears to
> have one, but I'm not completely sure what it does there. I'd check that it
> is indeed enabled.

The ar0130cs does have black level correction enabled by default.

My thought is that since the 12-bit data from the CCDC looked ok, that
it was something outside the sensor itself.

>> I've captured the 12-bit data from the CCDC, downconverted it to Y8,
>> and verified it looks ok, and is not washed out, so I'm suspecting the
>> isp previewer is doing something wrong in the simple Y10 to UYVY
>> conversion.
>
> Not necessarily wrong, the black level correction might be enabled by
> default, with the default configuration which works for most sensors (64 for
> 10-bit data, 16 for 8-bit etc.).

Ok, I will check this. You are referring to the "Camera ISP VPBE
Preview Black Adjustment" which is controlled by PRV_BLKADJOFF
register?

I also found that there are contrast and brightness settings in the
previewer which can be adjusted. I'm not changing them from defaults,
so I thought the "Y" values would just get truncated to 8 bits and
mapped into the UYVY without being significantly altered.

Would your thought be the black level is more likely the issue rather
than brightness/contrast?

Is there anywhere else I should look?

Thanks,
Chris