Hi Hans, On Mon, Sep 24, 2012 at 4:25 PM, Hans de Goede <hdegoede@xxxxxxxxxx> wrote: > Hi, > > > On 09/23/2012 01:26 PM, Prabhakar Lad wrote: >> >> Hi All, >> >> The CCD/Sensors have the capability to adjust the R/ye, Gr/Cy, Gb/G, >> B/Mg gain values. >> Since these control can be re-usable I am planning to add the >> following gain controls as part >> of the framework: >> >> 1: V4L2_CID_GAIN_RED >> 2: V4L2_CID_GAIN_GREEN_RED >> 3: V4L2_CID_GAIN_GREEN_BLUE > > > Not all sensors have separate V4L2_CID_GAIN_GREEN_RED / > V4L2_CID_GAIN_GREEN_BLUE, > so we will need a separate control for sensors which have one combined gain > called simply V4L2_CID_GAIN_GREEN > Agreed > Also do we really need separate V4L2_CID_GAIN_GREEN_RED / > V4L2_CID_GAIN_GREEN_BLUE > controls? I know hardware has them, but in my experience that is only done > as it > is simpler to make the hardware this way (fully symmetric sensor grid), have > you ever > tried actually using different gain settings for the 2 different green rows > ? > Never tried it. > I've and that always results in an ugly checker board pattern. So I think we > can > and should only have a V4L2_CID_GAIN_GREEN, and for sensors with 2 green > gains > have that control both, forcing both to always have the same setting, which > is > really what you want anyways ... > Agreed. Regards, --Prabhakar Lad >> 4: V4L2_CID_GAIN_BLUE >> 5: V4L2_CID_GAIN_OFFSET > > > GAIN_OFFSET that sounds a bit weird... GAIN_OFFSET sounds like it is > a number which gets added to the 3/4 gain settings before the gain gets > applied, > but I assume that you just mean a number which gets added to the value from > the pixel, either before or after the gain is applied and I must admit I > cannot > come up with a better name. > > I believe (not sure) that some sensors have these per color ... The question > is if it makes sense to actually control this per color though, I don't > think it > does as it is meant to compensate for any fixed measuring errors, which are > the > same for all 3/4 colors. Note that all the sensor cells are exactly the > same, > later on a color grid gets added on top of the sensors to turn them into > r/g/b > cells, but physically they are the same cells, so with the same process and > temperature caused measuring errors... > > Regards, > > Hans -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
