From patchwork Wed Apr 17 13:15:34 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dan Scally X-Patchwork-Id: 19898 Return-Path: X-Original-To: parsemail@patchwork.libcamera.org Delivered-To: parsemail@patchwork.libcamera.org Received: from lancelot.ideasonboard.com (lancelot.ideasonboard.com [92.243.16.209]) by patchwork.libcamera.org (Postfix) with ESMTPS id 6618DC3213 for ; Wed, 17 Apr 2024 13:16:08 +0000 (UTC) Received: from lancelot.ideasonboard.com (localhost [IPv6:::1]) by lancelot.ideasonboard.com (Postfix) with ESMTP id CA0566336B; Wed, 17 Apr 2024 15:16:07 +0200 (CEST) Authentication-Results: lancelot.ideasonboard.com; dkim=pass (1024-bit key; unprotected) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="fWqa1lcN"; dkim-atps=neutral Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) by lancelot.ideasonboard.com (Postfix) with ESMTPS id 23AC663363 for ; Wed, 17 Apr 2024 15:15:57 +0200 (CEST) Received: from mail.ideasonboard.com (cpc141996-chfd3-2-0-cust928.12-3.cable.virginm.net [86.13.91.161]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 076FDB7E; Wed, 17 Apr 2024 15:15:09 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1713359710; bh=/nN1mJOMfkfUaxWWtqn6DOazVJlnICfCsX4JO8QfPjk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fWqa1lcN/4L0igAiqEvHAWIue1JPet4SNB55ZmqJmqLMXO3Nfhh5b3PGnOchBSptI 1ZrYjenq09iEd9JV0RV/fiA4o6NJCK6moAsJtHa2WzkFOZb1hdq2W/O+F63zxI0Hsu BQUwVTqj2RC34KE0oSq2boUxthQSkqHVSf1BSa+E= From: Daniel Scally To: libcamera-devel@lists.libcamera.org Cc: Daniel Scally , Stefan Klug Subject: [PATCH v2 6/8] ipa: ipu3: Remove bespoke AGC functions from IPU3 Date: Wed, 17 Apr 2024 14:15:34 +0100 Message-Id: <20240417131536.484129-7-dan.scally@ideasonboard.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240417131536.484129-1-dan.scally@ideasonboard.com> References: <20240417131536.484129-1-dan.scally@ideasonboard.com> MIME-Version: 1.0 X-BeenThere: libcamera-devel@lists.libcamera.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: libcamera-devel-bounces@lists.libcamera.org Sender: "libcamera-devel" Now that the IPU3's Agc is derived from MeanLuminanceAgc we can delete all the unecessary bespoke functions. Reviewed-by: Stefan Klug Signed-off-by: Daniel Scally Reviewed-by: Jacopo Mondi --- Changes in v2: - Kept the documentation for estimateLuminance() src/ipa/ipu3/algorithms/agc.cpp | 227 +------------------------------- src/ipa/ipu3/algorithms/agc.h | 13 -- 2 files changed, 3 insertions(+), 237 deletions(-) diff --git a/src/ipa/ipu3/algorithms/agc.cpp b/src/ipa/ipu3/algorithms/agc.cpp index 3b9761bd..46fc3b33 100644 --- a/src/ipa/ipu3/algorithms/agc.cpp +++ b/src/ipa/ipu3/algorithms/agc.cpp @@ -125,8 +125,6 @@ int Agc::configure(IPAContext &context, activeState.agc.gain = minAnalogueGain_; activeState.agc.exposure = 10ms / configuration.sensor.lineDuration; - frameCount_ = 0; - context.activeState.agc.constraintMode = constraintModes().begin()->first; context.activeState.agc.exposureMode = exposureModeHelpers().begin()->first; @@ -139,42 +137,6 @@ int Agc::configure(IPAContext &context, return 0; } -/** - * \brief Estimate the mean value of the top 2% of the histogram - * \param[in] stats The statistics computed by the ImgU - * \param[in] grid The grid used to store the statistics in the IPU3 - * \return The mean value of the top 2% of the histogram - */ -double Agc::measureBrightness(const ipu3_uapi_stats_3a *stats, - const ipu3_uapi_grid_config &grid) const -{ - /* Initialise the histogram array */ - uint32_t hist[knumHistogramBins] = { 0 }; - - for (unsigned int cellY = 0; cellY < grid.height; cellY++) { - for (unsigned int cellX = 0; cellX < grid.width; cellX++) { - uint32_t cellPosition = cellY * stride_ + cellX; - - const ipu3_uapi_awb_set_item *cell = - reinterpret_cast( - &stats->awb_raw_buffer.meta_data[cellPosition] - ); - - uint8_t gr = cell->Gr_avg; - uint8_t gb = cell->Gb_avg; - /* - * Store the average green value to estimate the - * brightness. Even the overexposed pixels are - * taken into account. - */ - hist[(gr + gb) / 2]++; - } - } - - /* Estimate the quantile mean of the top 2% of the histogram. */ - return Histogram(Span(hist)).interQuantileMean(0.98, 1.0); -} - Histogram Agc::parseStatistics(const ipu3_uapi_stats_3a *stats, const ipu3_uapi_grid_config &grid) { @@ -208,123 +170,9 @@ Histogram Agc::parseStatistics(const ipu3_uapi_stats_3a *stats, return Histogram(Span(hist)); } -/** - * \brief Apply a filter on the exposure value to limit the speed of changes - * \param[in] exposureValue The target exposure from the AGC algorithm - * - * The speed of the filter is adaptive, and will produce the target quicker - * during startup, or when the target exposure is within 20% of the most recent - * filter output. - * - * \return The filtered exposure - */ -utils::Duration Agc::filterExposure(utils::Duration exposureValue) -{ - double speed = 0.2; - - /* Adapt instantly if we are in startup phase. */ - if (frameCount_ < kNumStartupFrames) - speed = 1.0; - - /* - * If we are close to the desired result, go faster to avoid making - * multiple micro-adjustments. - * \todo Make this customisable? - */ - if (filteredExposure_ < 1.2 * exposureValue && - filteredExposure_ > 0.8 * exposureValue) - speed = sqrt(speed); - - filteredExposure_ = speed * exposureValue + - filteredExposure_ * (1.0 - speed); - - LOG(IPU3Agc, Debug) << "After filtering, exposure " << filteredExposure_; - - return filteredExposure_; -} - -/** - * \brief Estimate the new exposure and gain values - * \param[inout] frameContext The shared IPA frame Context - * \param[in] yGain The gain calculated based on the relative luminance target - * \param[in] iqMeanGain The gain calculated based on the relative luminance target - */ -void Agc::computeExposure(IPAContext &context, IPAFrameContext &frameContext, - double yGain, double iqMeanGain) -{ - const IPASessionConfiguration &configuration = context.configuration; - /* Get the effective exposure and gain applied on the sensor. */ - uint32_t exposure = frameContext.sensor.exposure; - double analogueGain = frameContext.sensor.gain; - - /* Use the highest of the two gain estimates. */ - double evGain = std::max(yGain, iqMeanGain); - - /* Consider within 1% of the target as correctly exposed */ - if (utils::abs_diff(evGain, 1.0) < 0.01) - LOG(IPU3Agc, Debug) << "We are well exposed (evGain = " - << evGain << ")"; - - /* extracted from Rpi::Agc::computeTargetExposure */ - - /* Calculate the shutter time in seconds */ - utils::Duration currentShutter = exposure * configuration.sensor.lineDuration; - - /* - * Update the exposure value for the next computation using the values - * of exposure and gain really used by the sensor. - */ - utils::Duration effectiveExposureValue = currentShutter * analogueGain; - - LOG(IPU3Agc, Debug) << "Actual total exposure " << currentShutter * analogueGain - << " Shutter speed " << currentShutter - << " Gain " << analogueGain - << " Needed ev gain " << evGain; - - /* - * Calculate the current exposure value for the scene as the latest - * exposure value applied multiplied by the new estimated gain. - */ - utils::Duration exposureValue = effectiveExposureValue * evGain; - - /* Clamp the exposure value to the min and max authorized */ - utils::Duration maxTotalExposure = maxShutterSpeed_ * maxAnalogueGain_; - exposureValue = std::min(exposureValue, maxTotalExposure); - LOG(IPU3Agc, Debug) << "Target total exposure " << exposureValue - << ", maximum is " << maxTotalExposure; - - /* - * Filter the exposure. - * \todo estimate if we need to desaturate - */ - exposureValue = filterExposure(exposureValue); - - /* - * Divide the exposure value as new exposure and gain values. - * - * Push the shutter time up to the maximum first, and only then - * increase the gain. - */ - utils::Duration shutterTime = - std::clamp(exposureValue / minAnalogueGain_, - minShutterSpeed_, maxShutterSpeed_); - double stepGain = std::clamp(exposureValue / shutterTime, - minAnalogueGain_, maxAnalogueGain_); - LOG(IPU3Agc, Debug) << "Divided up shutter and gain are " - << shutterTime << " and " - << stepGain; -} - /** * \brief Estimate the relative luminance of the frame with a given gain - * \param[in] frameContext The shared IPA frame context - * \param[in] grid The grid used to store the statistics in the IPU3 - * \param[in] stats The IPU3 statistics and ISP results - * \param[in] gain The gain to apply to the frame - * \return The relative luminance - * - * This function estimates the average relative luminance of the frame that - * would be output by the sensor if an additional \a gain was applied. + * \param[in] gain The gain to apply in estimating luminance * * The estimation is based on the AWB statistics for the current frame. Red, * green and blue averages for all cells are first multiplied by the gain, and @@ -339,42 +187,9 @@ void Agc::computeExposure(IPAContext &context, IPAFrameContext &frameContext, * * More detailed information can be found in: * https://en.wikipedia.org/wiki/Relative_luminance + * + * @return The relative luminance of the frame */ -double Agc::estimateLuminance(IPAActiveState &activeState, - const ipu3_uapi_grid_config &grid, - const ipu3_uapi_stats_3a *stats, - double gain) -{ - double redSum = 0, greenSum = 0, blueSum = 0; - - /* Sum the per-channel averages, saturated to 255. */ - for (unsigned int cellY = 0; cellY < grid.height; cellY++) { - for (unsigned int cellX = 0; cellX < grid.width; cellX++) { - uint32_t cellPosition = cellY * stride_ + cellX; - - const ipu3_uapi_awb_set_item *cell = - reinterpret_cast( - &stats->awb_raw_buffer.meta_data[cellPosition] - ); - const uint8_t G_avg = (cell->Gr_avg + cell->Gb_avg) / 2; - - redSum += std::min(cell->R_avg * gain, 255.0); - greenSum += std::min(G_avg * gain, 255.0); - blueSum += std::min(cell->B_avg * gain, 255.0); - } - } - - /* - * Apply the AWB gains to approximate colours correctly, use the Rec. - * 601 formula to calculate the relative luminance, and normalize it. - */ - double ySum = redSum * activeState.awb.gains.red * 0.299 - + greenSum * activeState.awb.gains.green * 0.587 - + blueSum * activeState.awb.gains.blue * 0.114; - - return ySum / (grid.height * grid.width) / 255; -} - double Agc::estimateLuminance(double gain) { double redSum = 0, greenSum = 0, blueSum = 0; @@ -408,42 +223,6 @@ void Agc::process(IPAContext &context, [[maybe_unused]] const uint32_t frame, const ipu3_uapi_stats_3a *stats, ControlList &metadata) { - /* - * Estimate the gain needed to have the proportion of pixels in a given - * desired range. iqMean is the mean value of the top 2% of the - * cumulative histogram, and we want it to be as close as possible to a - * configured target. - */ - double iqMean = measureBrightness(stats, context.configuration.grid.bdsGrid); - double iqMeanGain = kEvGainTarget * knumHistogramBins / iqMean; - - /* - * Estimate the gain needed to achieve a relative luminance target. To - * account for non-linearity caused by saturation, the value needs to be - * estimated in an iterative process, as multiplying by a gain will not - * increase the relative luminance by the same factor if some image - * regions are saturated. - */ - double yGain = 1.0; - double yTarget = kRelativeLuminanceTarget; - - for (unsigned int i = 0; i < 8; i++) { - double yValue = estimateLuminance(context.activeState, - context.configuration.grid.bdsGrid, - stats, yGain); - double extraGain = std::min(10.0, yTarget / (yValue + .001)); - - yGain *= extraGain; - LOG(IPU3Agc, Debug) << "Y value: " << yValue - << ", Y target: " << yTarget - << ", gives gain " << yGain; - if (extraGain < 1.01) - break; - } - - computeExposure(context, frameContext, yGain, iqMeanGain); - frameCount_++; - Histogram hist = parseStatistics(stats, context.configuration.grid.bdsGrid); rGain_ = context.activeState.awb.gains.red; gGain_ = context.activeState.awb.gains.blue; diff --git a/src/ipa/ipu3/algorithms/agc.h b/src/ipa/ipu3/algorithms/agc.h index 40f32188..945d1846 100644 --- a/src/ipa/ipu3/algorithms/agc.h +++ b/src/ipa/ipu3/algorithms/agc.h @@ -38,29 +38,16 @@ public: ControlList &metadata) override; private: - double measureBrightness(const ipu3_uapi_stats_3a *stats, - const ipu3_uapi_grid_config &grid) const; - utils::Duration filterExposure(utils::Duration currentExposure); - void computeExposure(IPAContext &context, IPAFrameContext &frameContext, - double yGain, double iqMeanGain); - double estimateLuminance(IPAActiveState &activeState, - const ipu3_uapi_grid_config &grid, - const ipu3_uapi_stats_3a *stats, - double gain); double estimateLuminance(double gain) override; Histogram parseStatistics(const ipu3_uapi_stats_3a *stats, const ipu3_uapi_grid_config &grid); - uint64_t frameCount_; - utils::Duration minShutterSpeed_; utils::Duration maxShutterSpeed_; double minAnalogueGain_; double maxAnalogueGain_; - utils::Duration filteredExposure_; - uint32_t stride_; double rGain_; double gGain_;