2 files changed, 197 insertions, 29 deletions

diff --git a/src/ipa/rkisp1/algorithms/lsc.cpp b/src/ipa/rkisp1/algorithms/lsc.cpp
index e1c59033..3a443e77 100644
--- a/src/ipa/rkisp1/algorithms/lsc.cpp
+++ b/src/ipa/rkisp1/algorithms/lsc.cpp
@@ -7,6 +7,7 @@
 
 #include "lsc.h"
 
+#include <algorithm>
 #include <cmath>
 #include <numeric>
 
@@ -89,6 +90,7 @@ static std::vector<uint16_t> parseTable(const YamlObject &tuningData,
 }
 
 LensShadingCorrection::LensShadingCorrection()
+	: lastCt_({ 0, 0 })
 {
 }
 
@@ -104,14 +106,46 @@ int LensShadingCorrection::init([[maybe_unused]] IPAContext &context,
 	if (xSize_.empty() || ySize_.empty())
 		return -EINVAL;
 
-	rData_ = parseTable(tuningData, "r");
-	grData_ = parseTable(tuningData, "gr");
-	gbData_ = parseTable(tuningData, "gb");
-	bData_ = parseTable(tuningData, "b");
+	/* Get all defined sets to apply. */
+	const YamlObject &yamlSets = tuningData["sets"];
+	if (!yamlSets.isList()) {
+		LOG(RkISP1Lsc, Error)
+			<< "'sets' parameter not found in tuning file";
+		return -EINVAL;
+	}
+
+	const auto &sets = yamlSets.asList();
+	for (const auto &yamlSet : sets) {
+		uint32_t ct = yamlSet["ct"].get<uint32_t>(0);
+
+		if (sets_.count(ct)) {
+			LOG(RkISP1Lsc, Error)
+				<< "Multiple sets found for color temperature "
+				<< ct;
+			return -EINVAL;
+		}
+
+		Components &set = sets_[ct];
+
+		set.ct = ct;
+		set.r = parseTable(yamlSet, "r");
+		set.gr = parseTable(yamlSet, "gr");
+		set.gb = parseTable(yamlSet, "gb");
+		set.b = parseTable(yamlSet, "b");
+
+		if (set.r.empty() || set.gr.empty() ||
+		    set.gb.empty() || set.b.empty()) {
+			LOG(RkISP1Lsc, Error)
+				<< "Set for color temperature " << ct
+				<< " is missing tables";
+			return -EINVAL;
+		}
+	}
 
-	if (rData_.empty() || grData_.empty() ||
-	    gbData_.empty() || bData_.empty())
+	if (sets_.empty()) {
+		LOG(RkISP1Lsc, Error) << "Failed to load any sets";
 		return -EINVAL;
+	}
 
 	return 0;
 }
@@ -151,36 +185,154 @@ int LensShadingCorrection::configure(IPAContext &context,
 	return 0;
 }
 
+void LensShadingCorrection::setParameters(rkisp1_params_cfg *params)
+{
+	struct rkisp1_cif_isp_lsc_config &config = params->others.lsc_config;
+
+	memcpy(config.x_grad_tbl, xGrad_, sizeof(config.x_grad_tbl));
+	memcpy(config.y_grad_tbl, yGrad_, sizeof(config.y_grad_tbl));
+	memcpy(config.x_size_tbl, xSizes_, sizeof(config.x_size_tbl));
+	memcpy(config.y_size_tbl, ySizes_, sizeof(config.y_size_tbl));
+
+	params->module_en_update |= RKISP1_CIF_ISP_MODULE_LSC;
+	params->module_ens |= RKISP1_CIF_ISP_MODULE_LSC;
+	params->module_cfg_update |= RKISP1_CIF_ISP_MODULE_LSC;
+}
+
+void LensShadingCorrection::copyTable(rkisp1_cif_isp_lsc_config &config,
+				      const Components &set)
+{
+	std::copy(set.r.begin(), set.r.end(), &config.r_data_tbl[0][0]);
+	std::copy(set.gr.begin(), set.gr.end(), &config.gr_data_tbl[0][0]);
+	std::copy(set.gb.begin(), set.gb.end(), &config.gb_data_tbl[0][0]);
+	std::copy(set.b.begin(), set.b.end(), &config.b_data_tbl[0][0]);
+}
+
+/*
+ * Interpolate LSC parameters based on color temperature value.
+ */
+void LensShadingCorrection::interpolateTable(rkisp1_cif_isp_lsc_config &config,
+					     const Components &set0,
+					     const Components &set1,
+					     const uint32_t ct)
+{
+	double coeff0 = (set1.ct - ct) / (set1.ct - set0.ct);
+	double coeff1 = (ct - set0.ct) / (set1.ct - set0.ct);
+
+	for (unsigned int i = 0; i < RKISP1_CIF_ISP_LSC_SAMPLES_MAX; ++i) {
+		for (unsigned int j = 0; j < RKISP1_CIF_ISP_LSC_SAMPLES_MAX; ++j) {
+			unsigned int sample = i * RKISP1_CIF_ISP_LSC_SAMPLES_MAX + j;
+
+			config.r_data_tbl[i][j] =
+				set0.r[sample] * coeff0 +
+				set1.r[sample] * coeff1;
+
+			config.gr_data_tbl[i][j] =
+				set0.gr[sample] * coeff0 +
+				set1.gr[sample] * coeff1;
+
+			config.gb_data_tbl[i][j] =
+				set0.gb[sample] * coeff0 +
+				set1.gb[sample] * coeff1;
+
+			config.b_data_tbl[i][j] =
+				set0.b[sample] * coeff0 +
+				set1.b[sample] * coeff1;
+		}
+	}
+}
+
 /**
  * \copydoc libcamera::ipa::Algorithm::prepare
  */
-void LensShadingCorrection::prepare([[maybe_unused]] IPAContext &context,
+void LensShadingCorrection::prepare(IPAContext &context,
 				    const uint32_t frame,
 				    [[maybe_unused]] IPAFrameContext &frameContext,
 				    rkisp1_params_cfg *params)
 {
-	if (frame > 0)
+	struct rkisp1_cif_isp_lsc_config &config = params->others.lsc_config;
+
+	/*
+	 * If there is only one set, the configuration has already been done
+	 * for first frame.
+	 */
+	if (sets_.size() == 1 && frame > 0)
 		return;
 
-	struct rkisp1_cif_isp_lsc_config &config = params->others.lsc_config;
+	/*
+	 * If there is only one set, pick it. We can ignore lastCt_, as it will
+	 * never be relevant.
+	 */
+	if (sets_.size() == 1) {
+		setParameters(params);
+		copyTable(config, sets_.cbegin()->second);
+		return;
+	}
 
-	memcpy(config.x_grad_tbl, xGrad_, sizeof(config.x_grad_tbl));
-	memcpy(config.y_grad_tbl, yGrad_, sizeof(config.y_grad_tbl));
-	memcpy(config.x_size_tbl, xSizes_, sizeof(config.x_size_tbl));
-	memcpy(config.y_size_tbl, ySizes_, sizeof(config.y_size_tbl));
+	uint32_t ct = context.activeState.awb.temperatureK;
+	ct = std::clamp(ct, sets_.cbegin()->first, sets_.crbegin()->first);
 
-	std::copy(rData_.begin(), rData_.end(),
-		  &config.r_data_tbl[0][0]);
-	std::copy(grData_.begin(), grData_.end(),
-		  &config.gr_data_tbl[0][0]);
-	std::copy(gbData_.begin(), gbData_.end(),
-		  &config.gb_data_tbl[0][0]);
-	std::copy(bData_.begin(), bData_.end(),
-		  &config.b_data_tbl[0][0]);
+	/*
+	 * If the original is the same, then it means the same adjustment would
+	 * be made. If the adjusted is the same, then it means that it's the
+	 * same as what was actually applied. Thus in these cases we can skip
+	 * reprogramming the LSC.
+	 *
+	 * original == adjusted can only happen if an interpolation
+	 * happened, or if original has an exact entry in sets_. This means
+	 * that if original != adjusted, then original was adjusted to
+	 * the nearest available entry in sets_, resulting in adjusted.
+	 * Clearly, any ct value that is in between original and adjusted
+	 * will be adjusted to the same adjusted value, so we can skip
+	 * reprogramming the LSC table.
+	 *
+	 * We also skip updating the original value, as the last one had a
+	 * larger bound and thus a larger range of ct values that will be
+	 * adjusted to the same adjusted.
+	 */
+	if ((lastCt_.original <= ct && ct <= lastCt_.adjusted) ||
+	    (lastCt_.adjusted <= ct && ct <= lastCt_.original))
+		return;
 
-	params->module_en_update |= RKISP1_CIF_ISP_MODULE_LSC;
-	params->module_ens |= RKISP1_CIF_ISP_MODULE_LSC;
-	params->module_cfg_update |= RKISP1_CIF_ISP_MODULE_LSC;
+	setParameters(params);
+
+	/*
+	 * The color temperature matches exactly one of the available LSC tables.
+	 */
+	if (sets_.count(ct)) {
+		copyTable(config, sets_[ct]);
+		lastCt_ = { ct, ct };
+		return;
+	}
+
+	/* No shortcuts left; we need to round or interpolate */
+	auto iter = sets_.upper_bound(ct);
+	const Components &set1 = iter->second;
+	const Components &set0 = (--iter)->second;
+	uint32_t ct0 = set0.ct;
+	uint32_t ct1 = set1.ct;
+	uint32_t diff0 = ct - ct0;
+	uint32_t diff1 = ct1 - ct;
+	static constexpr double kThreshold = 0.1;
+	float threshold = kThreshold * (ct1 - ct0);
+
+	if (diff0 < threshold || diff1 < threshold) {
+		const Components &set = diff0 < diff1 ? set0 : set1;
+		LOG(RkISP1Lsc, Debug) << "using LSC table for " << set.ct;
+		copyTable(config, set);
+		lastCt_ = { ct, set.ct };
+		return;
+	}
+
+	/*
+	 * ct is not within 10% of the difference between the neighbouring
+	 * color temperatures, so we need to interpolate.
+	 */
+	LOG(RkISP1Lsc, Debug)
+		<< "ct is " << ct << ", interpolating between "
+		<< ct0 << " and " << ct1;
+	interpolateTable(config, set0, set1, ct);
+	lastCt_ = { ct, ct };
 }
 
 REGISTER_IPA_ALGORITHM(LensShadingCorrection, "LensShadingCorrection")
diff --git a/src/ipa/rkisp1/algorithms/lsc.h b/src/ipa/rkisp1/algorithms/lsc.h
index da81ea53..e2a93a56 100644
--- a/src/ipa/rkisp1/algorithms/lsc.h
+++ b/src/ipa/rkisp1/algorithms/lsc.h
@@ -7,6 +7,8 @@
 
 #pragma once
 
+#include <map>
+
 #include "algorithm.h"
 
 namespace libcamera {
@@ -26,17 +28,31 @@ public:
 		     rkisp1_params_cfg *params) override;
 
 private:
-	std::vector<uint16_t> rData_;
-	std::vector<uint16_t> grData_;
-	std::vector<uint16_t> gbData_;
-	std::vector<uint16_t> bData_;
-
+	struct Components {
+		uint32_t ct;
+		std::vector<uint16_t> r;
+		std::vector<uint16_t> gr;
+		std::vector<uint16_t> gb;
+		std::vector<uint16_t> b;
+	};
+
+	void setParameters(rkisp1_params_cfg *params);
+	void copyTable(rkisp1_cif_isp_lsc_config &config, const Components &set0);
+	void interpolateTable(rkisp1_cif_isp_lsc_config &config,
+			      const Components &set0, const Components &set1,
+			      const uint32_t ct);
+
+	std::map<uint32_t, Components> sets_;
 	std::vector<double> xSize_;
 	std::vector<double> ySize_;
 	uint16_t xGrad_[RKISP1_CIF_ISP_LSC_SECTORS_TBL_SIZE];
 	uint16_t yGrad_[RKISP1_CIF_ISP_LSC_SECTORS_TBL_SIZE];
 	uint16_t xSizes_[RKISP1_CIF_ISP_LSC_SECTORS_TBL_SIZE];
 	uint16_t ySizes_[RKISP1_CIF_ISP_LSC_SECTORS_TBL_SIZE];
+	struct {
+		uint32_t original;
+		uint32_t adjusted;
+	} lastCt_;
 };
 
 } /* namespace ipa::rkisp1::algorithms */