[libcamera-devel] [PATCH 09/20] ipa: rpi: Prepare ALSC for PiSP support

[Jacopo Mondi]

Hi Naush

On Fri, Oct 06, 2023 at 02:19:49PM +0100, Naushir Patuck via libcamera-devel wrote:
> Prepare the ALSC algorithm to support the PiSP hardware. The key change
> is to avoid factoring out the WB correction in the AWB zone statistics.
>
> Add the ALSC correction to the global metadata so that AWB can use it to
> factor the gains back in for the AWB calculations.
>
> Signed-off-by: Naushir Patuck <naush at raspberrypi.com>
> Reviewed-by: David Plowman <david.plowman at raspberrypi.com>

Reviewed-by: Jacopo Mondi <jacopo.mondi at ideasonboard.com>

Thanks
  j

> ---
>  src/ipa/rpi/controller/rpi/alsc.cpp | 16 ++++++++++++----
>  1 file changed, 12 insertions(+), 4 deletions(-)
>
> diff --git a/src/ipa/rpi/controller/rpi/alsc.cpp b/src/ipa/rpi/controller/rpi/alsc.cpp
> index 3a2e8fe00ca6..f1ccef87c70c 100644
> --- a/src/ipa/rpi/controller/rpi/alsc.cpp
> +++ b/src/ipa/rpi/controller/rpi/alsc.cpp
> @@ -348,9 +348,11 @@ static void copyStats(RgbyRegions &regions, StatisticsPtr &stats,
>  	const std::vector<double> &bTable = status.b;
>  	for (unsigned int i = 0; i < stats->awbRegions.numRegions(); i++) {
>  		auto r = stats->awbRegions.get(i);
> -		r.val.rSum = static_cast<uint64_t>(r.val.rSum / rTable[i]);
> -		r.val.gSum = static_cast<uint64_t>(r.val.gSum / gTable[i]);
> -		r.val.bSum = static_cast<uint64_t>(r.val.bSum / bTable[i]);
> +		if (stats->colourStatsPos == Statistics::ColourStatsPos::PostLsc) {
> +			r.val.rSum = static_cast<uint64_t>(r.val.rSum / rTable[i]);
> +			r.val.gSum = static_cast<uint64_t>(r.val.gSum / gTable[i]);
> +			r.val.bSum = static_cast<uint64_t>(r.val.bSum / bTable[i]);
> +		}
>  		regions.set(i, r);
>  	}
>  }
> @@ -368,7 +370,8 @@ void Alsc::restartAsync(StatisticsPtr &stats, Metadata *imageMetadata)
>  	 * the LSC table that the pipeline applied to them.
>  	 */
>  	AlscStatus alscStatus;
> -	if (imageMetadata->get("alsc.status", alscStatus) != 0) {
> +	if (stats->colourStatsPos == Statistics::ColourStatsPos::PostLsc &&
> +	    imageMetadata->get("alsc.status", alscStatus) != 0) {
>  		LOG(RPiAlsc, Warning)
>  			<< "No ALSC status found for applied gains!";
>  		alscStatus.r.resize(config_.tableSize.width * config_.tableSize.height, 1.0);
> @@ -414,6 +417,11 @@ void Alsc::prepare(Metadata *imageMetadata)
>  	status.g = prevSyncResults_[1].data();
>  	status.b = prevSyncResults_[2].data();
>  	imageMetadata->set("alsc.status", status);
> +	/*
> +	 * Put the results in the global metadata as well. This will be used by
> +	 * AWB to factor in the colour shading correction.
> +	 */
> +	getGlobalMetadata().set("alsc.status", status);
>  }
>
>  void Alsc::process(StatisticsPtr &stats, Metadata *imageMetadata)
> --
> 2.34.1
>