[PATCH v4 14/18] libcamera: software_isp: Move color handling to an algorithm module
Milan Zamazal
mzamazal at redhat.com
Thu Aug 15 10:16:18 CEST 2024
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 at redhat.com>
---
src/ipa/simple/algorithms/awb.cpp | 94 +++++++++++++++++++++++++++
src/ipa/simple/algorithms/awb.h | 43 ++++++++++++
src/ipa/simple/algorithms/gamma.cpp | 64 ++++++++++++++++++
src/ipa/simple/algorithms/gamma.h | 42 ++++++++++++
src/ipa/simple/algorithms/meson.build | 2 +
src/ipa/simple/data/uncalibrated.yaml | 2 +
src/ipa/simple/ipa_context.cpp | 30 +++++++++
src/ipa/simple/ipa_context.h | 12 ++++
src/ipa/simple/soft_simple.cpp | 66 ++-----------------
9 files changed, 293 insertions(+), 62 deletions(-)
create mode 100644 src/ipa/simple/algorithms/awb.cpp
create mode 100644 src/ipa/simple/algorithms/awb.h
create mode 100644 src/ipa/simple/algorithms/gamma.cpp
create mode 100644 src/ipa/simple/algorithms/gamma.h
diff --git a/src/ipa/simple/algorithms/awb.cpp b/src/ipa/simple/algorithms/awb.cpp
new file mode 100644
index 00000000..1e43f3fd
--- /dev/null
+++ b/src/ipa/simple/algorithms/awb.cpp
@@ -0,0 +1,94 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2024, Red Hat Inc.
+ *
+ * Auto white balance
+ */
+
+#include "awb.h"
+
+#include <algorithm>
+#include <numeric>
+#include <stdint.h>
+
+#include <libcamera/base/log.h>
+
+#include "simple/ipa_context.h"
+
+#include "gamma.h"
+
+namespace libcamera {
+
+LOG_DEFINE_CATEGORY(IPASoftAwb)
+
+namespace ipa::soft::algorithms {
+
+int Awb::init(IPAContext &context,
+ [[maybe_unused]] const YamlObject &tuningData)
+{
+ auto &gains = context.activeState.gains;
+ gains.red = gains.green = gains.blue = 256;
+
+ return 0;
+}
+
+void Awb::prepare(IPAContext &context,
+ [[maybe_unused]] const uint32_t frame,
+ [[maybe_unused]] IPAFrameContext &frameContext,
+ DebayerParams *params)
+{
+ 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 Awb::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(IPASoftAwb, Debug) << "gain R/B " << gains.red << "/" << gains.blue;
+}
+
+REGISTER_IPA_ALGORITHM(Awb, "Awb")
+
+} /* namespace ipa::soft::algorithms */
+
+} /* namespace libcamera */
diff --git a/src/ipa/simple/algorithms/awb.h b/src/ipa/simple/algorithms/awb.h
new file mode 100644
index 00000000..f94c1119
--- /dev/null
+++ b/src/ipa/simple/algorithms/awb.h
@@ -0,0 +1,43 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2024, Red Hat Inc.
+ *
+ * Auto white balance
+ */
+
+#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 Awb : public Algorithm
+{
+public:
+ Awb() = default;
+ ~Awb() = 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;
+};
+
+} /* namespace ipa::soft::algorithms */
+
+} /* namespace libcamera */
diff --git a/src/ipa/simple/algorithms/gamma.cpp b/src/ipa/simple/algorithms/gamma.cpp
new file mode 100644
index 00000000..0b8ec5ee
--- /dev/null
+++ b/src/ipa/simple/algorithms/gamma.cpp
@@ -0,0 +1,64 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2024, Red Hat Inc.
+ *
+ * Gamma table construction
+ */
+
+#include "gamma.h"
+
+#include <algorithm>
+#include <cmath>
+#include <stdint.h>
+
+#include <libcamera/base/log.h>
+
+#include "simple/ipa_context.h"
+
+namespace libcamera {
+
+namespace ipa::soft::algorithms {
+
+int Gamma::init(IPAContext &context,
+ [[maybe_unused]] const YamlObject &tuningData)
+{
+ /* Gamma value is fixed */
+ context.configuration.gamma = 0.5;
+ updateGammaTable(context);
+
+ return 0;
+}
+
+void Gamma::updateGammaTable(IPAContext &context)
+{
+ auto &gammaTable = context.activeState.gamma.gammaTable;
+ auto 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);
+ context.activeState.gamma.blackLevel = blackLevel;
+}
+
+void Gamma::prepare(IPAContext &context,
+ [[maybe_unused]] const uint32_t frame,
+ [[maybe_unused]] IPAFrameContext &frameContext,
+ [[maybe_unused]] DebayerParams *params)
+{
+ /*
+ * Update the gamma table if needed. This means if black level changes and
+ * since the black level gets updated only if a lower value is observed,
+ * it's not permanently prone to minor fluctuations or rounding errors.
+ */
+ if (context.activeState.gamma.blackLevel != context.activeState.black.level)
+ updateGammaTable(context);
+}
+
+REGISTER_IPA_ALGORITHM(Gamma, "Gamma")
+
+} /* namespace ipa::soft::algorithms */
+
+} /* namespace libcamera */
diff --git a/src/ipa/simple/algorithms/gamma.h b/src/ipa/simple/algorithms/gamma.h
new file mode 100644
index 00000000..43e88e87
--- /dev/null
+++ b/src/ipa/simple/algorithms/gamma.h
@@ -0,0 +1,42 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2024, Red Hat Inc.
+ *
+ * Gamma table construction
+ */
+
+#pragma once
+
+#include <libcamera/controls.h>
+
+#include "libcamera/internal/software_isp/debayer_params.h"
+
+#include "algorithm.h"
+#include "ipa_context.h"
+
+namespace libcamera {
+
+namespace ipa::soft::algorithms {
+
+static constexpr unsigned int kGammaLookupSize = 1024;
+
+class Gamma : public Algorithm
+{
+public:
+ Gamma() = default;
+ ~Gamma() = default;
+
+ int init(IPAContext &context, const YamlObject &tuningData)
+ override;
+ void prepare(IPAContext &context,
+ const uint32_t frame,
+ IPAFrameContext &frameContext,
+ DebayerParams *params) 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..de50fe6d 100644
--- a/src/ipa/simple/algorithms/meson.build
+++ b/src/ipa/simple/algorithms/meson.build
@@ -2,4 +2,6 @@
soft_simple_ipa_algorithms = files([
'blc.cpp',
+ 'gamma.cpp',
+ 'awb.cpp',
])
diff --git a/src/ipa/simple/data/uncalibrated.yaml b/src/ipa/simple/data/uncalibrated.yaml
index e0d03d96..3ca0a55f 100644
--- a/src/ipa/simple/data/uncalibrated.yaml
+++ b/src/ipa/simple/data/uncalibrated.yaml
@@ -4,4 +4,6 @@
version: 1
algorithms:
- BlackLevel:
+ - Gamma:
+ - Awb:
...
diff --git a/src/ipa/simple/ipa_context.cpp b/src/ipa/simple/ipa_context.cpp
index 268cff32..5fa492cb 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 22156569..f8b8834d 100644
--- a/src/ipa/simple/ipa_context.h
+++ b/src/ipa/simple/ipa_context.h
@@ -7,6 +7,7 @@
#pragma once
+#include <array>
#include <stdint.h>
#include <libipa/fc_queue.h>
@@ -16,12 +17,23 @@ 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 a1bd2f0c..8f01bf7d 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>
@@ -93,9 +91,6 @@ 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_;
@@ -283,6 +278,7 @@ 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(const uint32_t frame,
@@ -300,62 +296,6 @@ void IPASoftSimple::processStats(const uint32_t frame,
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(const uint32_t frame,
* 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(const uint32_t frame,
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);
}
--
2.44.1
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