[v3,09/15] ipa: rkisp1: lsc: Handle quantization locally
diff mbox series

Message ID 20260114-sklug-lsc-resampling-v2-dev-v3-9-80cd24f4dd61@ideasonboard.com
State New
Headers show
Series
  • Add resampling support for polynomial LSC data
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Commit Message

Stefan Klug Jan. 14, 2026, 11:58 a.m. UTC 
The quantization functionality in the Interpolator hinders in writing
nice code. Don't use it and implement the functionality directly in the
algorithm.

While at it, reduce the threshold to half of the quantization step size,
otherwise it might happen that we skip a full quantization step. Rename
the kColourTemperatureChangeThreshhold to kColourTemperatureQuantization
to better express the usecase.

Signed-off-by: Stefan Klug <stefan.klug@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

---

Changes in v3:
- Reduce threshold to quantization step/2
- Drop unnecessary static modifier
- Collected tag

Changes in v2:
- Added this patch
---
 src/ipa/rkisp1/algorithms/lsc.cpp | 25 ++++++++++++++++++-------
 1 file changed, 18 insertions(+), 7 deletions(-)

Patch
diff mbox series 

diff --git a/src/ipa/rkisp1/algorithms/lsc.cpp b/src/ipa/rkisp1/algorithms/lsc.cpp
index c42f74557c7364935254d75ee1fb923d176e0dbd..77ed0a95209ac13e82f4ee43f7a22095bb5fd65f 100644
--- a/src/ipa/rkisp1/algorithms/lsc.cpp
+++ b/src/ipa/rkisp1/algorithms/lsc.cpp
@@ -70,7 +70,7 @@  LOG_DEFINE_CATEGORY(RkISP1Lsc)
 
 namespace {
 
-constexpr int kColourTemperatureChangeThreshhold = 10;
+constexpr int kColourTemperatureQuantization = 10;
 
 class LscPolynomialLoader
 {
@@ -308,12 +308,16 @@  std::vector<double> parseSizes(const YamlObject &tuningData,
 	return sizes;
 }
 
+unsigned int quantize(unsigned int value, unsigned int step)
+{
+	return std::lround(value / static_cast<double>(step)) * step;
+}
+
 } /* namespace */
 
 LensShadingCorrection::LensShadingCorrection()
 	: lastAppliedCt_(0), lastAppliedQuantizedCt_(0)
 {
-	sets_.setQuantization(kColourTemperatureChangeThreshhold);
 }
 
 /**
@@ -426,17 +430,24 @@  void LensShadingCorrection::prepare([[maybe_unused]] IPAContext &context,
 				    RkISP1Params *params)
 {
 	uint32_t ct = frameContext.awb.temperatureK;
-	if (std::abs(static_cast<int>(ct) - static_cast<int>(lastAppliedCt_)) <
-	    kColourTemperatureChangeThreshhold)
+	unsigned int quantizedCt = quantize(ct, kColourTemperatureQuantization);
+	int ctDiff = static_cast<int>(ct) - static_cast<int>(lastAppliedCt_);
+
+	/*
+	 * Add a threshold so that oscillations around a quantization step don't
+	 * lead to constant changes.
+	 */
+	if (std::abs(ctDiff) < kColourTemperatureQuantization / 2)
 		return;
-	unsigned int quantizedCt;
-	const Components &set = sets_.getInterpolated(ct, &quantizedCt);
-	if (lastAppliedQuantizedCt_ == quantizedCt)
+
+	if (quantizedCt == lastAppliedQuantizedCt_)
 		return;
 
 	auto config = params->block<BlockType::Lsc>();
 	config.setEnabled(true);
 	setParameters(*config);
+
+	const Components &set = sets_.getInterpolated(quantizedCt);
 	copyTable(*config, set);
 
 	lastAppliedCt_ = ct;