[libcamera-devel] [PATCH v2 08/12] ipa: ipu3: awb: Correct the gain multipliers
Laurent Pinchart
laurent.pinchart at ideasonboard.com
Tue Oct 5 03:06:50 CEST 2021
Hi Jean-Michel,
Thank you for the patch.
On Thu, Sep 30, 2021 at 11:37:11AM +0200, Jean-Michel Hautbois wrote:
> The gains have a precision u3.13, range [0, 8[ which means that a gain
> multiplier value of 1.0 is represented as a multiplication by 8192 in
> the ImgU. Correct the gains as this was misunderstood in the first
> place.
>
> Signed-off-by: Jean-Michel Hautbois <jeanmichel.hautbois at ideasonboard.com>
> Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
> Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> ---
> src/ipa/ipu3/algorithms/awb.cpp | 15 ++++++---------
> 1 file changed, 6 insertions(+), 9 deletions(-)
>
> diff --git a/src/ipa/ipu3/algorithms/awb.cpp b/src/ipa/ipu3/algorithms/awb.cpp
> index be764c79..c1ff9450 100644
> --- a/src/ipa/ipu3/algorithms/awb.cpp
> +++ b/src/ipa/ipu3/algorithms/awb.cpp
> @@ -313,6 +313,7 @@ void Awb::awbGreyWorld()
> /* Color temperature is not relevant in Grey world but still useful to estimate it :-) */
> asyncResults_.temperatureK = estimateCCT(sumRed.R, sumRed.G, sumBlue.B);
> asyncResults_.redGain = redGain;
> + /*Hardcode the green gain to 1.0. */
Missing space before Hardcode.
> asyncResults_.greenGain = 1.0;
> asyncResults_.blueGain = blueGain;
> }
> @@ -376,15 +377,11 @@ void Awb::prepare(IPAContext &context, ipu3_uapi_params *params)
> * params->acc_param.bnr.opt_center.x_reset;
> params->acc_param.bnr.opt_center_sqr.y_sqr_reset = params->acc_param.bnr.opt_center.y_reset
> * params->acc_param.bnr.opt_center.y_reset;
> - /*
> - * Green gains should not be touched and considered 1.
> - * Default is 16, so do not change it at all.
> - * 4096 is the value for a gain of 1.0
> - */
> - params->acc_param.bnr.wb_gains.gr = 16 * context.frameContext.awb.gains.green;
> - params->acc_param.bnr.wb_gains.r = 4096 * context.frameContext.awb.gains.red;
> - params->acc_param.bnr.wb_gains.b = 4096 * context.frameContext.awb.gains.blue;
> - params->acc_param.bnr.wb_gains.gb = 16 * context.frameContext.awb.gains.green;
> + /* Convert to u3.13 fixed point values */
> + params->acc_param.bnr.wb_gains.gr = 8192 * context.frameContext.awb.gains.green;
> + params->acc_param.bnr.wb_gains.r = 8192 * context.frameContext.awb.gains.red;
> + params->acc_param.bnr.wb_gains.b = 8192 * context.frameContext.awb.gains.blue;
> + params->acc_param.bnr.wb_gains.gb = 8192 * context.frameContext.awb.gains.green;
>
> LOG(IPU3Awb, Debug) << "Color temperature estimated: " << asyncResults_.temperatureK;
>
--
Regards,
Laurent Pinchart
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