ipa: libipa: colour: Use the RGB class to model RGB values

The rec601LuminanceFromRGB() and estimateCCT() functions take RGB
triplets as three variables. Replace them with instances of the RGB
class and adapt the users accordingly. Only variables passed directly to
these functions are converted to RGB instances, further conversion of
IPA modules to the RGB class will be performed separately.

While at it, fix a typo in the documentation of the estimateCCT()
function.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Milan Zamazal <mzamazal@redhat.com>

1 files changed, 25 insertions, 22 deletions

diff --git a/src/ipa/rkisp1/algorithms/awb.cpp b/src/ipa/rkisp1/algorithms/awb.cpp
index 5c1d9511..dbeaf815 100644
--- a/src/ipa/rkisp1/algorithms/awb.cpp
+++ b/src/ipa/rkisp1/algorithms/awb.cpp
@@ -192,9 +192,7 @@ void Awb::process(IPAContext &context,
 	const rkisp1_cif_isp_stat *params = &stats->params;
 	const rkisp1_cif_isp_awb_stat *awb = &params->awb;
 	IPAActiveState &activeState = context.activeState;
-	double greenMean;
-	double redMean;
-	double blueMean;
+	RGB<double> rgbMeans;
 
 	metadata.set(controls::AwbEnable, frameContext.awb.autoEnabled);
 	metadata.set(controls::ColourGains, {
@@ -209,9 +207,11 @@ void Awb::process(IPAContext &context,
 	}
 
 	if (rgbMode_) {
-		greenMean = awb->awb_mean[0].mean_y_or_g;
-		redMean = awb->awb_mean[0].mean_cr_or_r;
-		blueMean = awb->awb_mean[0].mean_cb_or_b;
+		rgbMeans = {{
+			static_cast<double>(awb->awb_mean[0].mean_y_or_g),
+			static_cast<double>(awb->awb_mean[0].mean_cr_or_r),
+			static_cast<double>(awb->awb_mean[0].mean_cb_or_b)
+		}};
 	} else {
 		/* Get the YCbCr mean values */
 		double yMean = awb->awb_mean[0].mean_y_or_g;
@@ -233,9 +233,11 @@ void Awb::process(IPAContext &context,
 		yMean -= 16;
 		cbMean -= 128;
 		crMean -= 128;
-		redMean = 1.1636 * yMean - 0.0623 * cbMean + 1.6008 * crMean;
-		greenMean = 1.1636 * yMean - 0.4045 * cbMean - 0.7949 * crMean;
-		blueMean = 1.1636 * yMean + 1.9912 * cbMean - 0.0250 * crMean;
+		rgbMeans = {{
+			1.1636 * yMean - 0.0623 * cbMean + 1.6008 * crMean,
+			1.1636 * yMean - 0.4045 * cbMean - 0.7949 * crMean,
+			1.1636 * yMean + 1.9912 * cbMean - 0.0250 * crMean
+		}};
 
 		/*
 		 * Due to hardware rounding errors in the YCbCr means, the
@@ -243,9 +245,7 @@ void Awb::process(IPAContext &context,
 		 * negative gains, messing up calculation. Prevent this by
 		 * clamping the means to positive values.
 		 */
-		redMean = std::max(redMean, 0.0);
-		greenMean = std::max(greenMean, 0.0);
-		blueMean = std::max(blueMean, 0.0);
+		rgbMeans = rgbMeans.max(0.0);
 	}
 
 	/*
@@ -253,19 +253,22 @@ void Awb::process(IPAContext &context,
 	 * divide by the gains that were used to get the raw means from the
 	 * sensor.
 	 */
-	redMean /= frameContext.awb.gains.red;
-	greenMean /= frameContext.awb.gains.green;
-	blueMean /= frameContext.awb.gains.blue;
+	RGB<double> gains{{
+		frameContext.awb.gains.red,
+		frameContext.awb.gains.green,
+		frameContext.awb.gains.blue
+	}};
+	rgbMeans /= gains;
 
 	/*
 	 * If the means are too small we don't have enough information to
 	 * meaningfully calculate gains. Freeze the algorithm in that case.
 	 */
-	if (redMean < kMeanMinThreshold && greenMean < kMeanMinThreshold &&
-	    blueMean < kMeanMinThreshold)
+	if (rgbMeans.r() < kMeanMinThreshold && rgbMeans.g() < kMeanMinThreshold &&
+	    rgbMeans.b() < kMeanMinThreshold)
 		return;
 
-	activeState.awb.temperatureK = estimateCCT(redMean, greenMean, blueMean);
+	activeState.awb.temperatureK = estimateCCT(rgbMeans);
 
 	/* Metadata shall contain the up to date measurement */
 	metadata.set(controls::ColourTemperature, activeState.awb.temperatureK);
@@ -275,8 +278,8 @@ void Awb::process(IPAContext &context,
 	 * gain is hardcoded to 1.0. Avoid divisions by zero by clamping the
 	 * divisor to a minimum value of 1.0.
 	 */
-	double redGain = greenMean / std::max(redMean, 1.0);
-	double blueGain = greenMean / std::max(blueMean, 1.0);
+	double redGain = rgbMeans.g() / std::max(rgbMeans.r(), 1.0);
+	double blueGain = rgbMeans.g() / std::max(rgbMeans.b(), 1.0);
 
 	/*
 	 * Clamp the gain values to the hardware, which expresses gains as Q2.8
@@ -298,8 +301,8 @@ void Awb::process(IPAContext &context,
 
 	LOG(RkISP1Awb, Debug)
 		<< std::showpoint
-		<< "Means [" << redMean << ", " << greenMean << ", " << blueMean
-		<< "], gains [" << activeState.awb.gains.automatic.red << ", "
+		<< "Means " << rgbMeans
+		<< ", gains [" << activeState.awb.gains.automatic.red << ", "
 		<< activeState.awb.gains.automatic.green << ", "
 		<< activeState.awb.gains.automatic.blue << "], temp "
 		<< activeState.awb.temperatureK << "K";