[v1,2/4] ipa: libipa: agc_mean_luminance: Change luminance target to piecewise linear function

24642 diff mbox series

diff --git a/src/ipa/libipa/agc_mean_luminance.cpp b/src/ipa/libipa/agc_mean_luminance.cpp
index 64f36bd75dd2..62b1918a45a7 100644
--- a/src/ipa/libipa/agc_mean_luminance.cpp
+++ b/src/ipa/libipa/agc_mean_luminance.cpp
@@ -54,6 +54,14 @@  static constexpr double kDefaultRelativeLuminanceTarget = 0.16;
  */
 static constexpr double kMaxRelativeLuminanceTarget = 0.95;
 
+/*
+ * Default lux level
+ *
+ * If no lux level or a zero lux level is specified, but PWLs are used to
+ * specify luminance targets, this default level is used.
+ */
+static constexpr unsigned int kDefaultLuxLevel = 500;
+
 /**
  * \struct AgcMeanLuminance::AgcConstraint
  * \brief The boundaries and target for an AeConstraintMode constraint
@@ -145,16 +153,32 @@  static constexpr double kMaxRelativeLuminanceTarget = 0.95;
 
 AgcMeanLuminance::AgcMeanLuminance()
 	: exposureCompensation_(1.0), frameCount_(0), filteredExposure_(0s),
-	  relativeLuminanceTarget_(0)
+	  lux_(0)
 {
 }
 
 AgcMeanLuminance::~AgcMeanLuminance() = default;
 
-void AgcMeanLuminance::parseRelativeLuminanceTarget(const YamlObject &tuningData)
+int AgcMeanLuminance::parseRelativeLuminanceTarget(const YamlObject &tuningData)
 {
-	relativeLuminanceTarget_ =
-		tuningData["relativeLuminanceTarget"].get<double>(kDefaultRelativeLuminanceTarget);
+	relativeLuminanceTarget_.clear();
+
+	auto &target = tuningData["relativeLuminanceTarget"];
+	if (target.isValue()) {
+		double t = target.get<double>(kDefaultRelativeLuminanceTarget);
+		relativeLuminanceTarget_.append(0, t);
+		return 0;
+	}
+
+	std::optional<Pwl> pwl = target.get<Pwl>();
+	if (!pwl) {
+		LOG(AgcMeanLuminance, Error)
+			<< "Failed to load relative luminance target.";
+		return -EINVAL;
+	}
+
+	relativeLuminanceTarget_.swap(*pwl);
+	return 0;
 }
 
 void AgcMeanLuminance::parseConstraint(const YamlObject &modeDict, int32_t id)
@@ -385,7 +409,9 @@  int AgcMeanLuminance::parseTuningData(const YamlObject &tuningData)
 {
 	int ret;
 
-	parseRelativeLuminanceTarget(tuningData);
+	ret = parseRelativeLuminanceTarget(tuningData);
+	if (ret)
+		return ret;
 
 	ret = parseConstraintModes(tuningData);
 	if (ret)
@@ -403,6 +429,16 @@  int AgcMeanLuminance::parseTuningData(const YamlObject &tuningData)
  * AGC calculations. It is expressed as gain instead of EV.
  */
 
+/**
+ * \fn AgcMeanLuminance::setLux(int lux)
+ * \brief Set the lux level
+ * \param[in] lux The lux level
+ *
+ * This function sets the lux level to be used in the AGC calculations. A value
+ * of 0 means no measurement and a default value of \a kDefaultLuxLevel is used
+ * if necessary.
+ */
+
 /**
  * \brief Set the ExposureModeHelper limits for this class
  * \param[in] minExposureTime Minimum exposure time to allow
@@ -538,7 +574,18 @@  double AgcMeanLuminance::constraintClampGain(uint32_t constraintModeIndex,
  */
 double AgcMeanLuminance::effectiveYTarget() const
 {
-	return std::min(relativeLuminanceTarget_ * exposureCompensation_,
+	double lux = lux_;
+	if (relativeLuminanceTarget_.size() > 1 && lux_ == 0) {
+		LOG(AgcMeanLuminance, Debug)
+			<< "Missing lux value for luminance target calculation, default to "
+			<< kDefaultLuxLevel;
+		lux = kDefaultLuxLevel;
+	}
+
+	double luminanceTarget = relativeLuminanceTarget_.eval(
+		relativeLuminanceTarget_.domain().clamp(lux));
+
+	return std::min(luminanceTarget * exposureCompensation_,
 			kMaxRelativeLuminanceTarget);
 }
 
diff --git a/src/ipa/libipa/agc_mean_luminance.h b/src/ipa/libipa/agc_mean_luminance.h
index d7ec548e3e58..1fbff304a72b 100644
--- a/src/ipa/libipa/agc_mean_luminance.h
+++ b/src/ipa/libipa/agc_mean_luminance.h
@@ -20,6 +20,7 @@ 
 
 #include "exposure_mode_helper.h"
 #include "histogram.h"
+#include "pwl.h"
 
 namespace libcamera {
 
@@ -50,6 +51,11 @@  public:
 		exposureCompensation_ = gain;
 	}
 
+	void setLux(unsigned int lux)
+	{
+		lux_ = lux;
+	}
+
 	void setLimits(utils::Duration minExposureTime, utils::Duration maxExposureTime,
 		       double minGain, double maxGain, std::vector<AgcConstraint> constraints);
 
@@ -81,8 +87,8 @@  public:
 
 private:
 	virtual double estimateLuminance(const double gain) const = 0;
+	int parseRelativeLuminanceTarget(const YamlObject &tuningData);
 
-	void parseRelativeLuminanceTarget(const YamlObject &tuningData);
 	void parseConstraint(const YamlObject &modeDict, int32_t id);
 	int parseConstraintModes(const YamlObject &tuningData);
 	int parseExposureModes(const YamlObject &tuningData);
@@ -95,7 +101,8 @@  private:
 	double exposureCompensation_;
 	uint64_t frameCount_;
 	utils::Duration filteredExposure_;
-	double relativeLuminanceTarget_;
+	unsigned int lux_;
+	Pwl relativeLuminanceTarget_;
 
 	std::vector<AgcConstraint> additionalConstraints_;
 	std::map<int32_t, std::vector<AgcConstraint>> constraintModes_;
diff --git a/src/ipa/rkisp1/algorithms/agc.cpp b/src/ipa/rkisp1/algorithms/agc.cpp
index f5a3c917cb69..1ecaff680978 100644
--- a/src/ipa/rkisp1/algorithms/agc.cpp
+++ b/src/ipa/rkisp1/algorithms/agc.cpp
@@ -618,6 +618,7 @@  void Agc::process(IPAContext &context, [[maybe_unused]] const uint32_t frame,
 		effectiveExposureValue *= frameContext.agc.quantizationGain;
 
 	setExposureCompensation(pow(2.0, frameContext.agc.exposureValue));
+	setLux(frameContext.lux.lux);
 
 	utils::Duration newExposureTime;
 	double aGain, qGain, dGain;