From 93802f600cf4c3bf15c9d044b980927615e800f4 Mon Sep 17 00:00:00 2001 From: Jean-Michel Hautbois Date: Wed, 18 Aug 2021 17:54:03 +0200 Subject: ipa: ipu3: Move IPU3 agc into algorithms Now that the interface is properly used by the AGC class, move it into ipa::ipu3::algorithms and let the loops do the calls. As we need to exchange the exposure_ and gain_ by passing them through the FrameContext, use the calculated values in setControls() function to ease the reading. Signed-off-by: Jean-Michel Hautbois Reviewed-by: Kieran Bingham Reviewed-by: Laurent Pinchart --- src/ipa/ipu3/algorithms/agc.cpp | 200 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 200 insertions(+) create mode 100644 src/ipa/ipu3/algorithms/agc.cpp (limited to 'src/ipa/ipu3/algorithms/agc.cpp') diff --git a/src/ipa/ipu3/algorithms/agc.cpp b/src/ipa/ipu3/algorithms/agc.cpp new file mode 100644 index 00000000..e4598b2e --- /dev/null +++ b/src/ipa/ipu3/algorithms/agc.cpp @@ -0,0 +1,200 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ +/* + * Copyright (C) 2021, Ideas On Board + * + * ipu3_agc.cpp - AGC/AEC control algorithm + */ + +#include "agc.h" + +#include +#include +#include + +#include + +#include + +#include "libipa/histogram.h" + +namespace libcamera { + +using namespace std::literals::chrono_literals; + +namespace ipa::ipu3::algorithms { + +LOG_DEFINE_CATEGORY(IPU3Agc) + +/* Number of frames to wait before calculating stats on minimum exposure */ +static constexpr uint32_t kInitialFrameMinAECount = 4; +/* Number of frames to wait between new gain/exposure estimations */ +static constexpr uint32_t kFrameSkipCount = 6; + +/* Maximum ISO value for analogue gain */ +static constexpr uint32_t kMinISO = 100; +static constexpr uint32_t kMaxISO = 1500; + +/* Maximum analogue gain value + * \todo grab it from a camera helper */ +static constexpr uint32_t kMinGain = kMinISO / 100; +static constexpr uint32_t kMaxGain = kMaxISO / 100; + +/* \todo use calculated value based on sensor */ +static constexpr uint32_t kMinExposure = 1; +static constexpr uint32_t kMaxExposure = 1976; + +/* Histogram constants */ +static constexpr uint32_t knumHistogramBins = 256; +static constexpr double kEvGainTarget = 0.5; + +/* A cell is 8 bytes and contains averages for RGB values and saturation ratio */ +static constexpr uint8_t kCellSize = 8; + +Agc::Agc() + : frameCount_(0), lastFrame_(0), iqMean_(0.0), lineDuration_(0s), + maxExposureTime_(0s), prevExposure_(0s), prevExposureNoDg_(0s), + currentExposure_(0s), currentExposureNoDg_(0s) +{ +} + +int Agc::configure(IPAContext &context, const IPAConfigInfo &configInfo) +{ + aeGrid_ = context.configuration.grid.bdsGrid; + + lineDuration_ = configInfo.sensorInfo.lineLength * 1.0s + / configInfo.sensorInfo.pixelRate; + maxExposureTime_ = kMaxExposure * lineDuration_; + + return 0; +} + +void Agc::processBrightness(const ipu3_uapi_stats_3a *stats) +{ + const struct ipu3_uapi_grid_config statsAeGrid = stats->stats_4a_config.awb_config.grid; + Rectangle aeRegion = { statsAeGrid.x_start, + statsAeGrid.y_start, + static_cast(statsAeGrid.x_end - statsAeGrid.x_start) + 1, + static_cast(statsAeGrid.y_end - statsAeGrid.y_start) + 1 }; + Point topleft = aeRegion.topLeft(); + int topleftX = topleft.x >> aeGrid_.block_width_log2; + int topleftY = topleft.y >> aeGrid_.block_height_log2; + + /* Align to the grid cell width and height */ + uint32_t startX = topleftX << aeGrid_.block_width_log2; + uint32_t startY = topleftY * aeGrid_.width << aeGrid_.block_width_log2; + uint32_t endX = (startX + (aeRegion.size().width >> aeGrid_.block_width_log2)) << aeGrid_.block_width_log2; + uint32_t i, j; + uint32_t count = 0; + + uint32_t hist[knumHistogramBins] = { 0 }; + for (j = topleftY; + j < topleftY + (aeRegion.size().height >> aeGrid_.block_height_log2); + j++) { + for (i = startX + startY; i < endX + startY; i += kCellSize) { + /* + * The grid width (and maybe height) is not reliable. + * We observed a bit shift which makes the value 160 to be 32 in the stats grid. + * Use the one passed at init time. + */ + if (stats->awb_raw_buffer.meta_data[i + 4 + j * aeGrid_.width] == 0) { + uint8_t Gr = stats->awb_raw_buffer.meta_data[i + 0 + j * aeGrid_.width]; + uint8_t Gb = stats->awb_raw_buffer.meta_data[i + 3 + j * aeGrid_.width]; + hist[(Gr + Gb) / 2]++; + count++; + } + } + } + + /* Estimate the quantile mean of the top 2% of the histogram */ + iqMean_ = Histogram(Span(hist)).interQuantileMean(0.98, 1.0); +} + +void Agc::filterExposure() +{ + double speed = 0.2; + if (prevExposure_ == 0s) { + /* DG stands for digital gain.*/ + prevExposure_ = currentExposure_; + prevExposureNoDg_ = currentExposureNoDg_; + } else { + /* + * If we are close to the desired result, go faster to avoid making + * multiple micro-adjustments. + * \ todo: Make this customisable? + */ + if (prevExposure_ < 1.2 * currentExposure_ && + prevExposure_ > 0.8 * currentExposure_) + speed = sqrt(speed); + + prevExposure_ = speed * currentExposure_ + + prevExposure_ * (1.0 - speed); + prevExposureNoDg_ = speed * currentExposureNoDg_ + + prevExposureNoDg_ * (1.0 - speed); + } + /* + * We can't let the no_dg exposure deviate too far below the + * total exposure, as there might not be enough digital gain available + * in the ISP to hide it (which will cause nasty oscillation). + */ + double fastReduceThreshold = 0.4; + if (prevExposureNoDg_ < + prevExposure_ * fastReduceThreshold) + prevExposureNoDg_ = prevExposure_ * fastReduceThreshold; + LOG(IPU3Agc, Debug) << "After filtering, total_exposure " << prevExposure_; +} + +void Agc::lockExposureGain(uint32_t &exposure, double &gain) +{ + /* Algorithm initialization should wait for first valid frames */ + /* \todo - have a number of frames given by DelayedControls ? + * - implement a function for IIR */ + if ((frameCount_ < kInitialFrameMinAECount) || (frameCount_ - lastFrame_ < kFrameSkipCount)) + return; + + /* Are we correctly exposed ? */ + if (std::abs(iqMean_ - kEvGainTarget * knumHistogramBins) <= 1) { + LOG(IPU3Agc, Debug) << "!!! Good exposure with iqMean = " << iqMean_; + } else { + double newGain = kEvGainTarget * knumHistogramBins / iqMean_; + + /* extracted from Rpi::Agc::computeTargetExposure */ + libcamera::utils::Duration currentShutter = exposure * lineDuration_; + currentExposureNoDg_ = currentShutter * gain; + LOG(IPU3Agc, Debug) << "Actual total exposure " << currentExposureNoDg_ + << " Shutter speed " << currentShutter + << " Gain " << gain; + currentExposure_ = currentExposureNoDg_ * newGain; + libcamera::utils::Duration maxTotalExposure = maxExposureTime_ * kMaxGain; + currentExposure_ = std::min(currentExposure_, maxTotalExposure); + LOG(IPU3Agc, Debug) << "Target total exposure " << currentExposure_; + + /* \todo: estimate if we need to desaturate */ + filterExposure(); + + libcamera::utils::Duration newExposure = 0.0s; + if (currentShutter < maxExposureTime_) { + exposure = std::clamp(static_cast(exposure * currentExposure_ / currentExposureNoDg_), kMinExposure, kMaxExposure); + newExposure = currentExposure_ / exposure; + gain = std::clamp(static_cast(gain * currentExposure_ / newExposure), kMinGain, kMaxGain); + } else if (currentShutter >= maxExposureTime_) { + gain = std::clamp(static_cast(gain * currentExposure_ / currentExposureNoDg_), kMinGain, kMaxGain); + newExposure = currentExposure_ / gain; + exposure = std::clamp(static_cast(exposure * currentExposure_ / newExposure), kMinExposure, kMaxExposure); + } + LOG(IPU3Agc, Debug) << "Adjust exposure " << exposure * lineDuration_ << " and gain " << gain; + } + lastFrame_ = frameCount_; +} + +void Agc::process(IPAContext &context, const ipu3_uapi_stats_3a *stats) +{ + uint32_t &exposure = context.frameContext.agc.exposure; + double &gain = context.frameContext.agc.gain; + processBrightness(stats); + lockExposureGain(exposure, gain); + frameCount_++; +} + +} /* namespace ipa::ipu3::algorithms */ + +} /* namespace libcamera */ -- cgit v1.2.1