[PATCH v5 3/5] libcamera: software_isp: Move color mappings out of debayering
Milan Zamazal
mzamazal at redhat.com
Thu May 30 23:09:55 CEST 2024
Constructing the color mapping tables is related to stats rather than
debayering, where they are applied. Let's move the corresponding code
to stats processing.
The same applies to the auxiliary gamma table. As the gamma value is
currently fixed and used in a single place, with the temporary exception
mentioned below, there is no need to share it anywhere anymore.
It's necessary to initialize SoftwareIsp::debayerParams_ to default
values. These initial values are used for the first two frames, before
they are changed based on determined stats. To avoid sharing the gamma
value constant in artificial ways, we use 0.5 directly in the
initialization. This all is not a particularly elegant thing to do,
such a code belongs conceptually to the similar code in stats
processing, but doing better is left for larger refactoring.
This is a preliminary step towards building this functionality on top of
libipa/algorithm.h, which should follow.
Signed-off-by: Milan Zamazal <mzamazal at redhat.com>
Reviewed-by: Andrei Konovalov <andrey.konovalov.ynk at gmail.com>
---
.../internal/software_isp/debayer_params.h | 18 +++----
src/ipa/simple/soft_simple.cpp | 51 +++++++++++++++----
src/libcamera/software_isp/debayer.cpp | 29 +++++------
src/libcamera/software_isp/debayer_cpu.cpp | 43 +++-------------
src/libcamera/software_isp/debayer_cpu.h | 11 ++--
src/libcamera/software_isp/software_isp.cpp | 16 ++++--
6 files changed, 88 insertions(+), 80 deletions(-)
diff --git a/include/libcamera/internal/software_isp/debayer_params.h b/include/libcamera/internal/software_isp/debayer_params.h
index ce1b5945..463d24b3 100644
--- a/include/libcamera/internal/software_isp/debayer_params.h
+++ b/include/libcamera/internal/software_isp/debayer_params.h
@@ -1,6 +1,6 @@
/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
- * Copyright (C) 2023, Red Hat Inc.
+ * Copyright (C) 2023, 2024 Red Hat Inc.
*
* Authors:
* Hans de Goede <hdegoede at redhat.com>
@@ -10,20 +10,20 @@
#pragma once
+#include <array>
+#include <stdint.h>
+
namespace libcamera {
struct DebayerParams {
static constexpr unsigned int kGain10 = 256;
+ static constexpr unsigned int kRGBLookupSize = 256;
- unsigned int gainR;
- unsigned int gainG;
- unsigned int gainB;
+ using ColorLookupTable = std::array<uint8_t, kRGBLookupSize>;
- float gamma;
- /**
- * \brief Level of the black point, 0..255, 0 is no correction.
- */
- unsigned int blackLevel;
+ ColorLookupTable red;
+ ColorLookupTable green;
+ ColorLookupTable blue;
};
} /* namespace libcamera */
diff --git a/src/ipa/simple/soft_simple.cpp b/src/ipa/simple/soft_simple.cpp
index f383f994..3388686f 100644
--- a/src/ipa/simple/soft_simple.cpp
+++ b/src/ipa/simple/soft_simple.cpp
@@ -5,6 +5,7 @@
* Simple Software Image Processing Algorithm module
*/
+#include <cmath>
#include <numeric>
#include <stdint.h>
#include <sys/mman.h>
@@ -84,6 +85,10 @@ private:
ControlInfoMap sensorInfoMap_;
BlackLevel blackLevel_;
+ static constexpr unsigned int kGammaLookupSize = 1024;
+ std::array<uint8_t, kGammaLookupSize> gammaTable_;
+ int lastBlackLevel_ = -1;
+
int32_t exposureMin_, exposureMax_;
int32_t exposure_;
double againMin_, againMax_, againMinStep_;
@@ -246,7 +251,6 @@ void IPASoftSimple::processStats(const ControlList &sensorControls)
if (ignoreUpdates_ > 0)
blackLevel_.update(histogram);
const uint8_t blackLevel = blackLevel_.get();
- params_->blackLevel = blackLevel;
/*
* Black level must be subtracted to get the correct AWB ratios,
@@ -263,13 +267,42 @@ void IPASoftSimple::processStats(const ControlList &sensorControls)
/*
* 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.
*/
- params_->gainR = sumR <= sumG / 4 ? 1024 : 256 * sumG / sumR;
- params_->gainB = sumB <= sumG / 4 ? 1024 : 256 * sumG / sumB;
-
+ 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 */
- params_->gainG = 256;
- params_->gamma = 0.5;
+ 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 * DebayerParams::kGain10 /
+ 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();
@@ -290,7 +323,7 @@ void IPASoftSimple::processStats(const ControlList &sensorControls)
* https://www.araa.asn.au/acra/acra2007/papers/paper84final.pdf
*/
const unsigned int blackLevelHistIdx =
- params_->blackLevel / (256 / SwIspStats::kYHistogramSize);
+ blackLevel / (256 / SwIspStats::kYHistogramSize);
const unsigned int histogramSize =
SwIspStats::kYHistogramSize - blackLevelHistIdx;
const unsigned int yHistValsPerBin = histogramSize / kExposureBinsCount;
@@ -338,8 +371,8 @@ void IPASoftSimple::processStats(const ControlList &sensorControls)
LOG(IPASoft, Debug) << "exposureMSV " << exposureMSV
<< " exp " << exposure_ << " again " << again_
- << " gain R/B " << params_->gainR << "/" << params_->gainB
- << " black level " << params_->blackLevel;
+ << " gain R/B " << gainR << "/" << gainB
+ << " black level " << static_cast<unsigned int>(blackLevel);
}
void IPASoftSimple::updateExposure(double exposureMSV)
diff --git a/src/libcamera/software_isp/debayer.cpp b/src/libcamera/software_isp/debayer.cpp
index efe75ea8..3f3969f7 100644
--- a/src/libcamera/software_isp/debayer.cpp
+++ b/src/libcamera/software_isp/debayer.cpp
@@ -1,7 +1,7 @@
/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
* Copyright (C) 2023, Linaro Ltd
- * Copyright (C) 2023, Red Hat Inc.
+ * Copyright (C) 2023, 2024 Red Hat Inc.
*
* Authors:
* Hans de Goede <hdegoede at redhat.com>
@@ -24,29 +24,28 @@ namespace libcamera {
*/
/**
- * \var DebayerParams::gainR
- * \brief Red gain
- *
- * 128 = 0.5, 256 = 1.0, 512 = 2.0, etc.
+ * \var DebayerParams::kRGBLookupSize
+ * \brief Size of a color lookup table
*/
/**
- * \var DebayerParams::gainG
- * \brief Green gain
- *
- * 128 = 0.5, 256 = 1.0, 512 = 2.0, etc.
+ * \typedef DebayerParams::ColorLookupTable
+ * \brief Type of the lookup tables for red, green, blue values
*/
/**
- * \var DebayerParams::gainB
- * \brief Blue gain
- *
- * 128 = 0.5, 256 = 1.0, 512 = 2.0, etc.
+ * \var DebayerParams::red
+ * \brief Lookup table for red color, mapping input values to output values
+ */
+
+/**
+ * \var DebayerParams::green
+ * \brief Lookup table for green color, mapping input values to output values
*/
/**
- * \var DebayerParams::gamma
- * \brief Gamma correction, 1.0 is no correction
+ * \var DebayerParams::blue
+ * \brief Lookup table for blue color, mapping input values to output values
*/
/**
diff --git a/src/libcamera/software_isp/debayer_cpu.cpp b/src/libcamera/software_isp/debayer_cpu.cpp
index 8254bbe9..c038eed4 100644
--- a/src/libcamera/software_isp/debayer_cpu.cpp
+++ b/src/libcamera/software_isp/debayer_cpu.cpp
@@ -11,7 +11,6 @@
#include "debayer_cpu.h"
-#include <math.h>
#include <stdlib.h>
#include <time.h>
@@ -35,7 +34,7 @@ namespace libcamera {
* \param[in] stats Pointer to the stats object to use
*/
DebayerCpu::DebayerCpu(std::unique_ptr<SwStatsCpu> stats)
- : stats_(std::move(stats)), gammaCorrection_(1.0), blackLevel_(0)
+ : stats_(std::move(stats))
{
/*
* Reading from uncached buffers may be very slow.
@@ -47,9 +46,9 @@ DebayerCpu::DebayerCpu(std::unique_ptr<SwStatsCpu> stats)
*/
enableInputMemcpy_ = true;
- /* Initialize gamma to 1.0 curve */
- for (unsigned int i = 0; i < kGammaLookupSize; i++)
- gamma_[i] = i / (kGammaLookupSize / kRGBLookupSize);
+ /* Initialize color lookup tables */
+ for (unsigned int i = 0; i < DebayerParams::kRGBLookupSize; i++)
+ red_[i] = green_[i] = blue_[i] = i;
for (unsigned int i = 0; i < kMaxLineBuffers; i++)
lineBuffers_[i] = nullptr;
@@ -698,37 +697,9 @@ void DebayerCpu::process(FrameBuffer *input, FrameBuffer *output, DebayerParams
clock_gettime(CLOCK_MONOTONIC_RAW, &frameStartTime);
}
- /* Apply DebayerParams */
- if (params.gamma != gammaCorrection_ || params.blackLevel != blackLevel_) {
- const unsigned int blackIndex =
- params.blackLevel * kGammaLookupSize / 256;
- std::fill(gamma_.begin(), gamma_.begin() + blackIndex, 0);
- const float divisor = kGammaLookupSize - blackIndex - 1.0;
- for (unsigned int i = blackIndex; i < kGammaLookupSize; i++)
- gamma_[i] = UINT8_MAX * powf((i - blackIndex) / divisor, params.gamma);
-
- gammaCorrection_ = params.gamma;
- blackLevel_ = params.blackLevel;
- }
-
- if (swapRedBlueGains_)
- std::swap(params.gainR, params.gainB);
-
- for (unsigned int i = 0; i < kRGBLookupSize; i++) {
- constexpr unsigned int div =
- kRGBLookupSize * DebayerParams::kGain10 / kGammaLookupSize;
- unsigned int idx;
-
- /* Apply gamma after gain! */
- idx = std::min({ i * params.gainR / div, (kGammaLookupSize - 1) });
- red_[i] = gamma_[idx];
-
- idx = std::min({ i * params.gainG / div, (kGammaLookupSize - 1) });
- green_[i] = gamma_[idx];
-
- idx = std::min({ i * params.gainB / div, (kGammaLookupSize - 1) });
- blue_[i] = gamma_[idx];
- }
+ green_ = params.green;
+ red_ = swapRedBlueGains_ ? params.blue : params.red;
+ blue_ = swapRedBlueGains_ ? params.red : params.blue;
/* Copy metadata from the input buffer */
FrameMetadata &metadata = output->_d()->metadata();
diff --git a/src/libcamera/software_isp/debayer_cpu.h b/src/libcamera/software_isp/debayer_cpu.h
index de216fe3..be7dcdca 100644
--- a/src/libcamera/software_isp/debayer_cpu.h
+++ b/src/libcamera/software_isp/debayer_cpu.h
@@ -122,15 +122,12 @@ private:
void process2(const uint8_t *src, uint8_t *dst);
void process4(const uint8_t *src, uint8_t *dst);
- static constexpr unsigned int kGammaLookupSize = 1024;
- static constexpr unsigned int kRGBLookupSize = 256;
/* Max. supported Bayer pattern height is 4, debayering this requires 5 lines */
static constexpr unsigned int kMaxLineBuffers = 5;
- std::array<uint8_t, kGammaLookupSize> gamma_;
- std::array<uint8_t, kRGBLookupSize> red_;
- std::array<uint8_t, kRGBLookupSize> green_;
- std::array<uint8_t, kRGBLookupSize> blue_;
+ DebayerParams::ColorLookupTable red_;
+ DebayerParams::ColorLookupTable green_;
+ DebayerParams::ColorLookupTable blue_;
debayerFn debayer0_;
debayerFn debayer1_;
debayerFn debayer2_;
@@ -146,8 +143,6 @@ private:
unsigned int xShift_; /* Offset of 0/1 applied to window_.x */
bool enableInputMemcpy_;
bool swapRedBlueGains_;
- float gammaCorrection_;
- unsigned int blackLevel_;
unsigned int measuredFrames_;
int64_t frameProcessTime_;
/* Skip 30 frames for things to stabilize then measure 30 frames */
diff --git a/src/libcamera/software_isp/software_isp.cpp b/src/libcamera/software_isp/software_isp.cpp
index c9b6be56..2cde4f28 100644
--- a/src/libcamera/software_isp/software_isp.cpp
+++ b/src/libcamera/software_isp/software_isp.cpp
@@ -7,6 +7,8 @@
#include "libcamera/internal/software_isp/software_isp.h"
+#include <cmath>
+#include <stdint.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <unistd.h>
@@ -18,6 +20,7 @@
#include "libcamera/internal/framebuffer.h"
#include "libcamera/internal/ipa_manager.h"
#include "libcamera/internal/mapped_framebuffer.h"
+#include "libcamera/internal/software_isp/debayer_params.h"
#include "debayer_cpu.h"
@@ -63,10 +66,17 @@ LOG_DEFINE_CATEGORY(SoftwareIsp)
* handler
*/
SoftwareIsp::SoftwareIsp(PipelineHandler *pipe, const CameraSensor *sensor)
- : debayerParams_{ DebayerParams::kGain10, DebayerParams::kGain10,
- DebayerParams::kGain10, 0.5f, 0 },
- dmaHeap_(DmaHeap::DmaHeapFlag::Cma | DmaHeap::DmaHeapFlag::System)
+ : dmaHeap_(DmaHeap::DmaHeapFlag::Cma | DmaHeap::DmaHeapFlag::System)
{
+ std::array<uint8_t, 256> gammaTable;
+ for (unsigned int i = 0; i < 256; i++)
+ gammaTable[i] = UINT8_MAX * std::pow(i / 256.0, 0.5);
+ for (unsigned int i = 0; i < DebayerParams::kRGBLookupSize; i++) {
+ debayerParams_.red[i] = gammaTable[i];
+ debayerParams_.green[i] = gammaTable[i];
+ debayerParams_.blue[i] = gammaTable[i];
+ }
+
if (!dmaHeap_.isValid()) {
LOG(SoftwareIsp, Error) << "Failed to create DmaHeap object";
return;
--
2.42.0
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