diff options
Diffstat (limited to 'users/flokli/ipu6-softisp/libcamera/0018-libcamera-software_isp-Apply-black-level-compensatio.patch')
| -rw-r--r-- | users/flokli/ipu6-softisp/libcamera/0018-libcamera-software_isp-Apply-black-level-compensatio.patch | 396 |
1 files changed, 396 insertions, 0 deletions
diff --git a/users/flokli/ipu6-softisp/libcamera/0018-libcamera-software_isp-Apply-black-level-compensatio.patch b/users/flokli/ipu6-softisp/libcamera/0018-libcamera-software_isp-Apply-black-level-compensatio.patch new file mode 100644 index 000000000000..c746b74dba67 --- /dev/null +++ b/users/flokli/ipu6-softisp/libcamera/0018-libcamera-software_isp-Apply-black-level-compensatio.patch @@ -0,0 +1,396 @@ +From bb608d177135d74e3c98b8a61fb459ebe254bca5 Mon Sep 17 00:00:00 2001 +From: Milan Zamazal <mzamazal@redhat.com> +Date: Mon, 11 Mar 2024 15:15:21 +0100 +Subject: [PATCH 18/21] libcamera: software_isp: Apply black level compensation + +Black may not be represented as 0 pixel value for given hardware, it may be +higher. If this is not compensated then various problems may occur such as low +contrast or suboptimal exposure. + +The black pixel value can be either retrieved from a tuning file for the given +hardware, or automatically on fly. The former is the right and correct method, +while the latter can be used when a tuning file is not available for the given +hardware. Since there is currently no support for tuning files in software ISP, +the automatic, hardware independent way, is always used. Support for tuning +files should be added in future but it will require more work than this patch. + +The patch looks at the image histogram and assumes that black starts when pixel +values start occurring on the left. A certain amount of the darkest pixels is +ignored; it doesn't matter whether they represent various kinds of noise or are +real, they are better to omit in any case to make the image looking better. It +also doesn't matter whether the darkest pixels occur around the supposed black +level or are spread between 0 and the black level, the difference is not +important. + +An arbitrary threshold of 2% darkest pixels is applied; there is no magic about +that value. + +The patch assumes that the black values for different colors are the same and +doesn't attempt any other non-primitive enhancements. It cannot completely +replace tuning files and simplicity, while providing visible benefit, is its +goal. Anything more sophisticated is left for future patches. + +A possible cheap enhancement, if needed, could be setting exposure + gain to +minimum values temporarily, before setting the black level. In theory, the +black level should be fixed but it may not be reached in all images. For this +reason, the patch updates black level only if the observed value is lower than +the current one; it should be never increased. + +The purpose of the patch is to compensate for hardware properties. General +image contrast enhancements are out of scope of this patch. + +Stats are still gathered as an uncorrected histogram, to avoid any confusion and +to represent the raw image data. Exposure must be determined after the black +level correction -- it has no influence on the sub-black area and must be +correct after applying the black level correction. The granularity of the +histogram is increased from 16 to 64 to provide a better precision (there is no +theory behind either of those numbers). + +Reviewed-by: Hans de Goede <hdegoede@redhat.com> +Signed-off-by: Milan Zamazal <mzamazal@redhat.com> +Signed-off-by: Hans de Goede <hdegoede@redhat.com> +--- + .../internal/software_isp/debayer_params.h | 4 + + .../internal/software_isp/swisp_stats.h | 10 ++- + src/ipa/simple/black_level.cpp | 86 +++++++++++++++++++ + src/ipa/simple/black_level.h | 28 ++++++ + src/ipa/simple/meson.build | 7 +- + src/ipa/simple/soft_simple.cpp | 28 ++++-- + src/libcamera/software_isp/debayer_cpu.cpp | 13 ++- + src/libcamera/software_isp/debayer_cpu.h | 1 + + src/libcamera/software_isp/software_isp.cpp | 2 +- + 9 files changed, 162 insertions(+), 17 deletions(-) + create mode 100644 src/ipa/simple/black_level.cpp + create mode 100644 src/ipa/simple/black_level.h + +diff --git a/include/libcamera/internal/software_isp/debayer_params.h b/include/libcamera/internal/software_isp/debayer_params.h +index 98965fa1..5e38e08b 100644 +--- a/include/libcamera/internal/software_isp/debayer_params.h ++++ b/include/libcamera/internal/software_isp/debayer_params.h +@@ -43,6 +43,10 @@ struct DebayerParams { + * \brief Gamma correction, 1.0 is no correction + */ + float gamma; ++ /** ++ * \brief Level of the black point, 0..255, 0 is no correction. ++ */ ++ unsigned int blackLevel; + }; + + } /* namespace libcamera */ +diff --git a/include/libcamera/internal/software_isp/swisp_stats.h b/include/libcamera/internal/software_isp/swisp_stats.h +index afe42c9a..25cd5abd 100644 +--- a/include/libcamera/internal/software_isp/swisp_stats.h ++++ b/include/libcamera/internal/software_isp/swisp_stats.h +@@ -7,6 +7,8 @@ + + #pragma once + ++#include <array> ++ + namespace libcamera { + + /** +@@ -28,11 +30,15 @@ struct SwIspStats { + /** + * \brief Number of bins in the yHistogram. + */ +- static constexpr unsigned int kYHistogramSize = 16; ++ static constexpr unsigned int kYHistogramSize = 64; ++ /** ++ * \brief Type of the histogram. ++ */ ++ using histogram = std::array<unsigned int, kYHistogramSize>; + /** + * \brief A histogram of luminance values. + */ +- std::array<unsigned int, kYHistogramSize> yHistogram; ++ histogram yHistogram; + }; + + } /* namespace libcamera */ +diff --git a/src/ipa/simple/black_level.cpp b/src/ipa/simple/black_level.cpp +new file mode 100644 +index 00000000..8d52201b +--- /dev/null ++++ b/src/ipa/simple/black_level.cpp +@@ -0,0 +1,86 @@ ++/* SPDX-License-Identifier: LGPL-2.1-or-later */ ++/* ++ * Copyright (C) 2024, Red Hat Inc. ++ * ++ * black_level.cpp - black level handling ++ */ ++ ++#include "black_level.h" ++ ++#include <numeric> ++ ++#include <libcamera/base/log.h> ++ ++namespace libcamera { ++ ++LOG_DEFINE_CATEGORY(IPASoftBL) ++ ++/** ++ * \class BlackLevel ++ * \brief Object providing black point level for software ISP ++ * ++ * Black level can be provided in hardware tuning files or, if no tuning file is ++ * available for the given hardware, guessed automatically, with less accuracy. ++ * As tuning files are not yet implemented for software ISP, BlackLevel ++ * currently provides only guessed black levels. ++ * ++ * This class serves for tracking black level as a property of the underlying ++ * hardware, not as means of enhancing a particular scene or image. ++ * ++ * The class is supposed to be instantiated for the given camera stream. ++ * The black level can be retrieved using BlackLevel::get() method. It is ++ * initially 0 and may change when updated using BlackLevel::update() method. ++ */ ++ ++BlackLevel::BlackLevel() ++ : blackLevel_(255), blackLevelSet_(false) ++{ ++} ++ ++/** ++ * \brief Return the current black level ++ * ++ * \return The black level, in the range from 0 (minimum) to 255 (maximum). ++ * If the black level couldn't be determined yet, return 0. ++ */ ++unsigned int BlackLevel::get() const ++{ ++ return blackLevelSet_ ? blackLevel_ : 0; ++} ++ ++/** ++ * \brief Update black level from the provided histogram ++ * \param[in] yHistogram The histogram to be used for updating black level ++ * ++ * The black level is property of the given hardware, not image. It is updated ++ * only if it has not been yet set or if it is lower than the lowest value seen ++ * so far. ++ */ ++void BlackLevel::update(SwIspStats::histogram &yHistogram) ++{ ++ // The constant is selected to be "good enough", not overly conservative or ++ // aggressive. There is no magic about the given value. ++ constexpr float ignoredPercentage_ = 0.02; ++ const unsigned int total = ++ std::accumulate(begin(yHistogram), end(yHistogram), 0); ++ const unsigned int pixelThreshold = ignoredPercentage_ * total; ++ const unsigned int currentBlackIdx = ++ blackLevel_ / (256 / SwIspStats::kYHistogramSize); ++ ++ for (unsigned int i = 0, seen = 0; ++ i < currentBlackIdx && i < SwIspStats::kYHistogramSize; ++ i++) { ++ seen += yHistogram[i]; ++ if (seen >= pixelThreshold) { ++ blackLevel_ = i * (256 / SwIspStats::kYHistogramSize); ++ blackLevelSet_ = true; ++ LOG(IPASoftBL, Debug) ++ << "Auto-set black level: " ++ << i << "/" << SwIspStats::kYHistogramSize ++ << " (" << 100 * (seen - yHistogram[i]) / total << "% below, " ++ << 100 * seen / total << "% at or below)"; ++ break; ++ } ++ }; ++} ++} // namespace libcamera +diff --git a/src/ipa/simple/black_level.h b/src/ipa/simple/black_level.h +new file mode 100644 +index 00000000..b3785db0 +--- /dev/null ++++ b/src/ipa/simple/black_level.h +@@ -0,0 +1,28 @@ ++/* SPDX-License-Identifier: LGPL-2.1-or-later */ ++/* ++ * Copyright (C) 2024, Red Hat Inc. ++ * ++ * black_level.h - black level handling ++ */ ++ ++#pragma once ++ ++#include <array> ++ ++#include "libcamera/internal/software_isp/swisp_stats.h" ++ ++namespace libcamera { ++ ++class BlackLevel ++{ ++public: ++ BlackLevel(); ++ unsigned int get() const; ++ void update(std::array<unsigned int, SwIspStats::kYHistogramSize> &yHistogram); ++ ++private: ++ unsigned int blackLevel_; ++ bool blackLevelSet_; ++}; ++ ++} // namespace libcamera +diff --git a/src/ipa/simple/meson.build b/src/ipa/simple/meson.build +index 3e863db7..44b5f1d7 100644 +--- a/src/ipa/simple/meson.build ++++ b/src/ipa/simple/meson.build +@@ -2,8 +2,13 @@ + + ipa_name = 'ipa_soft_simple' + ++soft_simple_sources = files([ ++ 'soft_simple.cpp', ++ 'black_level.cpp', ++]) ++ + mod = shared_module(ipa_name, +- ['soft_simple.cpp', libcamera_generated_ipa_headers], ++ [soft_simple_sources, libcamera_generated_ipa_headers], + name_prefix : '', + include_directories : [ipa_includes, libipa_includes], + dependencies : libcamera_private, +diff --git a/src/ipa/simple/soft_simple.cpp b/src/ipa/simple/soft_simple.cpp +index 312df4ba..ac027568 100644 +--- a/src/ipa/simple/soft_simple.cpp ++++ b/src/ipa/simple/soft_simple.cpp +@@ -22,6 +22,8 @@ + #include "libcamera/internal/software_isp/debayer_params.h" + #include "libcamera/internal/software_isp/swisp_stats.h" + ++#include "black_level.h" ++ + namespace libcamera { + + LOG_DEFINE_CATEGORY(IPASoft) +@@ -33,7 +35,8 @@ class IPASoftSimple : public ipa::soft::IPASoftInterface + public: + IPASoftSimple() + : params_(static_cast<DebayerParams *>(MAP_FAILED)), +- stats_(static_cast<SwIspStats *>(MAP_FAILED)), ignore_updates_(0) ++ stats_(static_cast<SwIspStats *>(MAP_FAILED)), ++ blackLevel_(BlackLevel()), ignore_updates_(0) + { + } + +@@ -63,6 +66,7 @@ private: + SharedFD fdParams_; + DebayerParams *params_; + SwIspStats *stats_; ++ BlackLevel blackLevel_; + + int32_t exposure_min_, exposure_max_; + int32_t again_min_, again_max_; +@@ -196,6 +200,10 @@ void IPASoftSimple::processStats(const ControlList &sensorControls) + params_->gainG = 256; + params_->gamma = 0.5; + ++ if (ignore_updates_ > 0) ++ blackLevel_.update(stats_->yHistogram); ++ params_->blackLevel = blackLevel_.get(); ++ + setIspParams.emit(0); + + /* +@@ -211,18 +219,19 @@ void IPASoftSimple::processStats(const ControlList &sensorControls) + * Calculate Mean Sample Value (MSV) according to formula from: + * https://www.araa.asn.au/acra/acra2007/papers/paper84final.pdf + */ +- constexpr unsigned int yHistValsPerBin = +- SwIspStats::kYHistogramSize / kExposureBinsCount; +- constexpr unsigned int yHistValsPerBinMod = +- SwIspStats::kYHistogramSize / +- (SwIspStats::kYHistogramSize % kExposureBinsCount + 1); ++ const unsigned int blackLevelHistIdx = ++ params_->blackLevel / (256 / SwIspStats::kYHistogramSize); ++ const unsigned int histogramSize = SwIspStats::kYHistogramSize - blackLevelHistIdx; ++ const unsigned int yHistValsPerBin = histogramSize / kExposureBinsCount; ++ const unsigned int yHistValsPerBinMod = ++ histogramSize / (histogramSize % kExposureBinsCount + 1); + int ExposureBins[kExposureBinsCount] = {}; + unsigned int denom = 0; + unsigned int num = 0; + +- for (unsigned int i = 0; i < SwIspStats::kYHistogramSize; i++) { ++ for (unsigned int i = 0; i < histogramSize; i++) { + unsigned int idx = (i - (i / yHistValsPerBinMod)) / yHistValsPerBin; +- ExposureBins[idx] += stats_->yHistogram[i]; ++ ExposureBins[idx] += stats_->yHistogram[blackLevelHistIdx + i]; + } + + for (unsigned int i = 0; i < kExposureBinsCount; i++) { +@@ -256,7 +265,8 @@ void IPASoftSimple::processStats(const ControlList &sensorControls) + + LOG(IPASoft, Debug) << "exposureMSV " << exposureMSV + << " exp " << exposure_ << " again " << again_ +- << " gain R/B " << params_->gainR << "/" << params_->gainB; ++ << " gain R/B " << params_->gainR << "/" << params_->gainB ++ << " black level " << params_->blackLevel; + } + + void IPASoftSimple::updateExposure(double exposureMSV) +diff --git a/src/libcamera/software_isp/debayer_cpu.cpp b/src/libcamera/software_isp/debayer_cpu.cpp +index a1692693..3be3cdfe 100644 +--- a/src/libcamera/software_isp/debayer_cpu.cpp ++++ b/src/libcamera/software_isp/debayer_cpu.cpp +@@ -35,7 +35,7 @@ namespace libcamera { + * \param[in] stats Pointer to the stats object to use. + */ + DebayerCpu::DebayerCpu(std::unique_ptr<SwStatsCpu> stats) +- : stats_(std::move(stats)), gamma_correction_(1.0) ++ : stats_(std::move(stats)), gamma_correction_(1.0), blackLevel_(0) + { + #ifdef __x86_64__ + enableInputMemcpy_ = false; +@@ -683,11 +683,16 @@ void DebayerCpu::process(FrameBuffer *input, FrameBuffer *output, DebayerParams + } + + /* Apply DebayerParams */ +- if (params.gamma != gamma_correction_) { +- for (unsigned int i = 0; i < kGammaLookupSize; i++) +- gamma_[i] = UINT8_MAX * powf(i / (kGammaLookupSize - 1.0), params.gamma); ++ if (params.gamma != gamma_correction_ || 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); + + gamma_correction_ = params.gamma; ++ blackLevel_ = params.blackLevel; + } + + if (swapRedBlueGains_) +diff --git a/src/libcamera/software_isp/debayer_cpu.h b/src/libcamera/software_isp/debayer_cpu.h +index 5f44fc65..ea02f909 100644 +--- a/src/libcamera/software_isp/debayer_cpu.h ++++ b/src/libcamera/software_isp/debayer_cpu.h +@@ -147,6 +147,7 @@ private: + bool enableInputMemcpy_; + bool swapRedBlueGains_; + float gamma_correction_; ++ 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 388b4496..9b49be41 100644 +--- a/src/libcamera/software_isp/software_isp.cpp ++++ b/src/libcamera/software_isp/software_isp.cpp +@@ -64,7 +64,7 @@ LOG_DEFINE_CATEGORY(SoftwareIsp) + */ + SoftwareIsp::SoftwareIsp(PipelineHandler *pipe, const ControlInfoMap &sensorControls) + : debayer_(nullptr), +- debayerParams_{ DebayerParams::kGain10, DebayerParams::kGain10, DebayerParams::kGain10, 0.5f }, ++ debayerParams_{ DebayerParams::kGain10, DebayerParams::kGain10, DebayerParams::kGain10, 0.5f, 0 }, + dmaHeap_(DmaHeap::DmaHeapFlag::Cma | DmaHeap::DmaHeapFlag::System) + { + if (!dmaHeap_.isValid()) { +-- +2.43.2 + |