[v2,15/19] libcamera: software_isp: Move color handling to an algorithm module
diff mbox series

Message ID 20240703175119.1872585-16-mzamazal@redhat.com
State New
Headers show
Series
  • Software ISP refactoring
Related show

Commit Message

Milan Zamazal July 3, 2024, 5:51 p.m. UTC
After black level handling has been moved to an algorithm module, white
balance and the construction of color tables can be moved to an
algorithm module too.  This time, the moved code is split between stats
processing and parameter construction methods.

This is the only part of the software ISP algorithms that sets the
parameters so emitting setIspParams can be moved to prepare() method.

A more natural representation of the gains (and black level) would be
floating point numbers.  This is not done here in order to minimize
changes in code movements.  It will be addressed in a followup patch.

Signed-off-by: Milan Zamazal <mzamazal@redhat.com>
---
 src/ipa/simple/algorithms/colors.cpp  | 121 ++++++++++++++++++++++++++
 src/ipa/simple/algorithms/colors.h    |  46 ++++++++++
 src/ipa/simple/algorithms/meson.build |   1 +
 src/ipa/simple/data/uncalibrated.yaml |   1 +
 src/ipa/simple/ipa_context.cpp        |  30 +++++++
 src/ipa/simple/ipa_context.h          |  12 +++
 src/ipa/simple/soft_simple.cpp        |  66 +-------------
 7 files changed, 215 insertions(+), 62 deletions(-)
 create mode 100644 src/ipa/simple/algorithms/colors.cpp
 create mode 100644 src/ipa/simple/algorithms/colors.h

Patch
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diff --git a/src/ipa/simple/algorithms/colors.cpp b/src/ipa/simple/algorithms/colors.cpp
new file mode 100644
index 00000000..60fdca15
--- /dev/null
+++ b/src/ipa/simple/algorithms/colors.cpp
@@ -0,0 +1,121 @@ 
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2024, Red Hat Inc.
+ *
+ * Color gains (AWB + gamma)
+ */
+
+#include "colors.h"
+
+#include <algorithm>
+#include <cmath>
+#include <numeric>
+#include <stdint.h>
+
+#include <libcamera/base/log.h>
+
+#include "simple/ipa_context.h"
+
+namespace libcamera {
+
+LOG_DEFINE_CATEGORY(IPASoftColors)
+
+namespace ipa::soft::algorithms {
+
+static constexpr unsigned int kGammaLookupSize = 1024;
+
+Colors::Colors()
+{
+}
+
+int Colors::init(IPAContext &context,
+		 [[maybe_unused]] const YamlObject &tuningData)
+{
+	/* Gamma value is fixed */
+	context.configuration.gamma = 0.5;
+	updateGammaTable(context);
+
+	auto &gains = context.activeState.gains;
+	gains.red = gains.green = gains.blue = 256;
+
+	return 0;
+}
+
+void Colors::updateGammaTable(IPAContext &context)
+{
+	auto &gammaTable = context.activeState.gamma.gammaTable;
+	auto &blackLevel = context.activeState.gamma.blackLevel;
+	blackLevel = context.activeState.black.level;
+	const unsigned int blackIndex =
+		blackLevel * IPAActiveState::kGammaLookupSize / 256;
+	std::fill(gammaTable.begin(), gammaTable.begin() + blackIndex, 0);
+	const float divisor = kGammaLookupSize - blackIndex - 1.0;
+	for (unsigned int i = blackIndex; i < kGammaLookupSize; i++)
+		gammaTable[i] = UINT8_MAX * powf((i - blackIndex) / divisor,
+						 context.configuration.gamma);
+}
+
+void Colors::prepare(IPAContext &context,
+		     [[maybe_unused]] const uint32_t frame,
+		     [[maybe_unused]] IPAFrameContext &frameContext,
+		     DebayerParams *params)
+{
+	/* Update the gamma table if needed */
+	if (context.activeState.gamma.blackLevel != context.activeState.black.level)
+		updateGammaTable(context);
+
+	auto &gains = context.activeState.gains;
+	auto &gammaTable = context.activeState.gamma.gammaTable;
+	for (unsigned int i = 0; i < DebayerParams::kRGBLookupSize; i++) {
+		constexpr unsigned int div =
+			static_cast<double>(DebayerParams::kRGBLookupSize) * 256 / kGammaLookupSize;
+		/* Apply gamma after gain! */
+		unsigned int idx;
+		idx = std::min({ i * gains.red / div, kGammaLookupSize - 1 });
+		params->red[i] = gammaTable[idx];
+		idx = std::min({ i * gains.green / div, kGammaLookupSize - 1 });
+		params->green[i] = gammaTable[idx];
+		idx = std::min({ i * gains.blue / div, kGammaLookupSize - 1 });
+		params->blue[i] = gammaTable[idx];
+	}
+}
+
+void Colors::process(IPAContext &context,
+		     [[maybe_unused]] const uint32_t frame,
+		     [[maybe_unused]] IPAFrameContext &frameContext,
+		     const SwIspStats *stats,
+		     [[maybe_unused]] ControlList &metadata)
+{
+	const SwIspStats::Histogram &histogram = stats->yHistogram;
+	const uint8_t blackLevel = context.activeState.black.level;
+
+	/*
+	 * Black level must be subtracted to get the correct AWB ratios, they
+	 * would be off if they were computed from the whole brightness range
+	 * rather than from the sensor range.
+	 */
+	const uint64_t nPixels = std::accumulate(
+		histogram.begin(), histogram.end(), 0);
+	const uint64_t offset = blackLevel * nPixels;
+	const uint64_t sumR = stats->sumR_ - offset / 4;
+	const uint64_t sumG = stats->sumG_ - offset / 2;
+	const uint64_t sumB = stats->sumB_ - offset / 4;
+
+	/*
+	 * Calculate red and blue gains for AWB.
+	 * Clamp max gain at 4.0, this also avoids 0 division.
+	 * Gain: 128 = 0.5, 256 = 1.0, 512 = 2.0, etc.
+	 */
+	auto &gains = context.activeState.gains;
+	gains.red = sumR <= sumG / 4 ? 1024 : 256 * sumG / sumR;
+	gains.blue = sumB <= sumG / 4 ? 1024 : 256 * sumG / sumB;
+	/* Green gain is fixed to 256 */
+
+	LOG(IPASoftColors, Debug) << "gain R/B " << gains.red << "/" << gains.blue;
+}
+
+REGISTER_IPA_ALGORITHM(Colors, "Colors")
+
+} /* namespace ipa::soft::algorithms */
+
+} /* namespace libcamera */
diff --git a/src/ipa/simple/algorithms/colors.h b/src/ipa/simple/algorithms/colors.h
new file mode 100644
index 00000000..2c2f7752
--- /dev/null
+++ b/src/ipa/simple/algorithms/colors.h
@@ -0,0 +1,46 @@ 
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2024, Red Hat Inc.
+ *
+ * Color gains (AWB + gamma)
+ */
+
+#pragma once
+
+#include <libcamera/controls.h>
+
+#include "libcamera/internal/software_isp/debayer_params.h"
+#include "libcamera/internal/software_isp/swisp_stats.h"
+
+#include "algorithm.h"
+#include "ipa_context.h"
+
+namespace libcamera {
+
+namespace ipa::soft::algorithms {
+
+class Colors : public Algorithm
+{
+public:
+	Colors();
+	~Colors() = default;
+
+	int init(IPAContext &context, const YamlObject &tuningData)
+		override;
+	void prepare(IPAContext &context,
+		     const uint32_t frame,
+		     IPAFrameContext &frameContext,
+		     DebayerParams *params) override;
+	void process(IPAContext &context,
+		     const uint32_t frame,
+		     IPAFrameContext &frameContext,
+		     const SwIspStats *stats,
+		     ControlList &metadata) override;
+
+private:
+	void updateGammaTable(IPAContext &context);
+};
+
+} /* namespace ipa::soft::algorithms */
+
+} /* namespace libcamera */
diff --git a/src/ipa/simple/algorithms/meson.build b/src/ipa/simple/algorithms/meson.build
index 1f63c220..324c7b4e 100644
--- a/src/ipa/simple/algorithms/meson.build
+++ b/src/ipa/simple/algorithms/meson.build
@@ -2,4 +2,5 @@ 
 
 soft_simple_ipa_algorithms = files([
     'blc.cpp',
+    'colors.cpp',
 ])
diff --git a/src/ipa/simple/data/uncalibrated.yaml b/src/ipa/simple/data/uncalibrated.yaml
index e0d03d96..7e5149e5 100644
--- a/src/ipa/simple/data/uncalibrated.yaml
+++ b/src/ipa/simple/data/uncalibrated.yaml
@@ -4,4 +4,5 @@ 
 version: 1
 algorithms:
   - BlackLevel:
+  - Colors:
 ...
diff --git a/src/ipa/simple/ipa_context.cpp b/src/ipa/simple/ipa_context.cpp
index bb5daa0d..fc113527 100644
--- a/src/ipa/simple/ipa_context.cpp
+++ b/src/ipa/simple/ipa_context.cpp
@@ -50,6 +50,11 @@  namespace libcamera::ipa::soft {
  * \brief The current state of IPA algorithms
  */
 
+/**
+ * \var IPASessionConfiguration::gamma
+ * \brief Gamma value to be used in the raw image processing
+ */
+
 /**
  * \var IPAActiveState::black
  * \brief Context for the Black Level algorithm
@@ -58,4 +63,29 @@  namespace libcamera::ipa::soft {
  * \brief Current determined black level
  */
 
+/**
+ * \var IPAActiveState::gains
+ * \brief Context for gains in the Colors algorithm
+ *
+ * \var IPAActiveState::gains.red
+ * \brief Gain of red color
+ *
+ * \var IPAActiveState::gains.green
+ * \brief Gain of green color
+ *
+ * \var IPAActiveState::gains.blue
+ * \brief Gain of blue color
+ */
+
+/**
+ * \var IPAActiveState::gamma
+ * \brief Context for gamma in the Colors algorithm
+ *
+ * \var IPAActiveState::gamma.gammaTable
+ * \brief Computed gamma table
+ *
+ * \var IPAActiveState::gamma.blackLevel
+ * \brief Black level used for the gamma table computation
+ */
+
 } /* namespace libcamera::ipa::soft */
diff --git a/src/ipa/simple/ipa_context.h b/src/ipa/simple/ipa_context.h
index ed07dbb8..979ddb8f 100644
--- a/src/ipa/simple/ipa_context.h
+++ b/src/ipa/simple/ipa_context.h
@@ -8,6 +8,7 @@ 
 
 #pragma once
 
+#include <array>
 #include <stdint.h>
 
 #include <libipa/fc_queue.h>
@@ -17,12 +18,23 @@  namespace libcamera {
 namespace ipa::soft {
 
 struct IPASessionConfiguration {
+	float gamma;
 };
 
 struct IPAActiveState {
 	struct {
 		uint8_t level;
 	} black;
+	struct {
+		unsigned int red;
+		unsigned int green;
+		unsigned int blue;
+	} gains;
+	static constexpr unsigned int kGammaLookupSize = 1024;
+	struct {
+		std::array<double, kGammaLookupSize> gammaTable;
+		uint8_t blackLevel;
+	} gamma;
 };
 
 struct IPAFrameContext : public FrameContext {
diff --git a/src/ipa/simple/soft_simple.cpp b/src/ipa/simple/soft_simple.cpp
index 2fb3a473..2658e359 100644
--- a/src/ipa/simple/soft_simple.cpp
+++ b/src/ipa/simple/soft_simple.cpp
@@ -5,8 +5,6 @@ 
  * Simple Software Image Processing Algorithm module
  */
 
-#include <cmath>
-#include <numeric>
 #include <stdint.h>
 #include <sys/mman.h>
 
@@ -92,9 +90,6 @@  private:
 	std::unique_ptr<CameraSensorHelper> camHelper_;
 	ControlInfoMap sensorInfoMap_;
 
-	static constexpr unsigned int kGammaLookupSize = 1024;
-	std::array<uint8_t, kGammaLookupSize> gammaTable_;
-	int lastBlackLevel_ = -1;
 	/* Local parameter storage */
 	struct IPAContext context_;
 
@@ -282,6 +277,7 @@  void IPASoftSimple::prepare(const uint32_t frame)
 	IPAFrameContext &frameContext = context_.frameContexts.get(frame);
 	for (auto const &algo : algorithms())
 		algo->prepare(context_, frame, frameContext, params_);
+	setIspParams.emit();
 }
 
 void IPASoftSimple::processStats(
@@ -300,62 +296,6 @@  void IPASoftSimple::processStats(
 	for (auto const &algo : algorithms())
 		algo->process(context_, frame, frameContext, stats_, metadata);
 
-	SwIspStats::Histogram histogram = stats_->yHistogram;
-	const uint8_t blackLevel = context_.activeState.black.level;
-
-	/*
-	 * Black level must be subtracted to get the correct AWB ratios, they
-	 * would be off if they were computed from the whole brightness range
-	 * rather than from the sensor range.
-	 */
-	const uint64_t nPixels = std::accumulate(
-		histogram.begin(), histogram.end(), 0);
-	const uint64_t offset = blackLevel * nPixels;
-	const uint64_t sumR = stats_->sumR_ - offset / 4;
-	const uint64_t sumG = stats_->sumG_ - offset / 2;
-	const uint64_t sumB = stats_->sumB_ - offset / 4;
-
-	/*
-	 * Calculate red and blue gains for AWB.
-	 * Clamp max gain at 4.0, this also avoids 0 division.
-	 * Gain: 128 = 0.5, 256 = 1.0, 512 = 2.0, etc.
-	 */
-	const unsigned int gainR = sumR <= sumG / 4 ? 1024 : 256 * sumG / sumR;
-	const unsigned int gainB = sumB <= sumG / 4 ? 1024 : 256 * sumG / sumB;
-	/* Green gain and gamma values are fixed */
-	constexpr unsigned int gainG = 256;
-
-	/* Update the gamma table if needed */
-	if (blackLevel != lastBlackLevel_) {
-		constexpr float gamma = 0.5;
-		const unsigned int blackIndex = blackLevel * kGammaLookupSize / 256;
-		std::fill(gammaTable_.begin(), gammaTable_.begin() + blackIndex, 0);
-		const float divisor = kGammaLookupSize - blackIndex - 1.0;
-		for (unsigned int i = blackIndex; i < kGammaLookupSize; i++)
-			gammaTable_[i] = UINT8_MAX *
-					 std::pow((i - blackIndex) / divisor, gamma);
-
-		lastBlackLevel_ = blackLevel;
-	}
-
-	for (unsigned int i = 0; i < DebayerParams::kRGBLookupSize; i++) {
-		constexpr unsigned int div =
-			DebayerParams::kRGBLookupSize * 256 / kGammaLookupSize;
-		unsigned int idx;
-
-		/* Apply gamma after gain! */
-		idx = std::min({ i * gainR / div, (kGammaLookupSize - 1) });
-		params_->red[i] = gammaTable_[idx];
-
-		idx = std::min({ i * gainG / div, (kGammaLookupSize - 1) });
-		params_->green[i] = gammaTable_[idx];
-
-		idx = std::min({ i * gainB / div, (kGammaLookupSize - 1) });
-		params_->blue[i] = gammaTable_[idx];
-	}
-
-	setIspParams.emit();
-
 	/* \todo Switch to the libipa/algorithm.h API someday. */
 
 	/*
@@ -372,6 +312,7 @@  void IPASoftSimple::processStats(
 	 * Calculate Mean Sample Value (MSV) according to formula from:
 	 * https://www.araa.asn.au/acra/acra2007/papers/paper84final.pdf
 	 */
+	const uint8_t blackLevel = context_.activeState.black.level;
 	const unsigned int blackLevelHistIdx =
 		blackLevel / (256 / SwIspStats::kYHistogramSize);
 	const unsigned int histogramSize =
@@ -421,7 +362,8 @@  void IPASoftSimple::processStats(
 
 	LOG(IPASoft, Debug) << "exposureMSV " << exposureMSV
 			    << " exp " << exposure_ << " again " << again_
-			    << " gain R/B " << gainR << "/" << gainB
+			    << " gain R/B " << context_.activeState.gains.red
+			    << "/" << context_.activeState.gains.blue
 			    << " black level " << static_cast<unsigned int>(blackLevel);
 }