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 + 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; /** * \brief A histogram of luminance values. */ - std::array 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..9d4aa800 --- /dev/null +++ b/src/ipa/simple/black_level.cpp @@ -0,0 +1,88 @@ +/* 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 + +#include + +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 histogramRatio = 256 / SwIspStats::kYHistogramSize; + const unsigned int currentBlackIdx = blackLevel_ / histogramRatio; + + for (unsigned int i = 0, seen = 0; + i < currentBlackIdx && i < SwIspStats::kYHistogramSize; + i++) { + seen += yHistogram[i]; + if (seen >= pixelThreshold) { + blackLevel_ = i * histogramRatio; + 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 + +#include "libcamera/internal/software_isp/swisp_stats.h" + +namespace libcamera { + +class BlackLevel +{ +public: + BlackLevel(); + unsigned int get() const; + void update(std::array &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(MAP_FAILED)), - stats_(static_cast(MAP_FAILED)), ignore_updates_(0) + stats_(static_cast(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 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()) {