From patchwork Fri Aug 8 14:12:46 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Klug X-Patchwork-Id: 24079 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 B6CAFBDCC1 for ; Fri, 8 Aug 2025 14:14:08 +0000 (UTC) Received: from lancelot.ideasonboard.com (localhost [IPv6:::1]) by lancelot.ideasonboard.com (Postfix) with ESMTP id 7174769221; Fri, 8 Aug 2025 16:14:08 +0200 (CEST) Authentication-Results: lancelot.ideasonboard.com; dkim=pass (1024-bit key; unprotected) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="i4uRovtf"; dkim-atps=neutral Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) by lancelot.ideasonboard.com (Postfix) with ESMTPS id D779F6921E for ; Fri, 8 Aug 2025 16:14:06 +0200 (CEST) Received: from ideasonboard.com (unknown [IPv6:2a00:6020:448c:6c00:3ea1:35ac:90da:a221]) by perceval.ideasonboard.com (Postfix) with UTF8SMTPSA id EE3C8208E; Fri, 8 Aug 2025 16:13:16 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1754662397; bh=YWAo715sOGCFW3ImcQFI4ZffXYRkbNiSP01cyq3p3hg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=i4uRovtf6oOfSqocOpGCYnIh1VZQhSbg86ePdysKJgmcWOidIKr45LeY8I2IePf7X uhOLcjrXdApcdMqIr+8JIv9JD+oiC3GdjoFuqLSkIiiVzoa5bfsd0loz7QnDOkuE/H aFoEHNfOOqOPgRmK5vtdu/UEI/KwL7z6SyGUQwro= From: Stefan Klug To: libcamera-devel@lists.libcamera.org Cc: Stefan Klug Subject: [PATCH v2 08/16] libipa: exposure_mode_helper: Calculate quantization gain in splitExposure() Date: Fri, 8 Aug 2025 16:12:46 +0200 Message-ID: <20250808141315.413839-9-stefan.klug@ideasonboard.com> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250808141315.413839-1-stefan.klug@ideasonboard.com> References: <20250808141315.413839-1-stefan.klug@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" Calculate the error introduced by quantization as "quantization gain" and return it separately from splitExposure(). It is not included in the digital gain, to not silently ignore the limits imposed by the AGC configuration. Signed-off-by: Stefan Klug --- src/ipa/ipu3/algorithms/agc.cpp | 4 +-- src/ipa/libipa/agc_mean_luminance.cpp | 7 ++-- src/ipa/libipa/agc_mean_luminance.h | 2 +- src/ipa/libipa/exposure_mode_helper.cpp | 46 +++++++++++++++++-------- src/ipa/libipa/exposure_mode_helper.h | 2 +- src/ipa/rkisp1/algorithms/agc.cpp | 9 ++--- 6 files changed, 44 insertions(+), 26 deletions(-) diff --git a/src/ipa/ipu3/algorithms/agc.cpp b/src/ipa/ipu3/algorithms/agc.cpp index 39d0aebb0838..da045640d569 100644 --- a/src/ipa/ipu3/algorithms/agc.cpp +++ b/src/ipa/ipu3/algorithms/agc.cpp @@ -222,8 +222,8 @@ void Agc::process(IPAContext &context, [[maybe_unused]] const uint32_t frame, utils::Duration effectiveExposureValue = exposureTime * analogueGain; utils::Duration newExposureTime; - double aGain, dGain; - std::tie(newExposureTime, aGain, dGain) = + double aGain, qGain, dGain; + std::tie(newExposureTime, aGain, qGain, dGain) = calculateNewEv(context.activeState.agc.constraintMode, context.activeState.agc.exposureMode, hist, effectiveExposureValue); diff --git a/src/ipa/libipa/agc_mean_luminance.cpp b/src/ipa/libipa/agc_mean_luminance.cpp index 58c4dfc9add2..695453e7ceea 100644 --- a/src/ipa/libipa/agc_mean_luminance.cpp +++ b/src/ipa/libipa/agc_mean_luminance.cpp @@ -566,11 +566,12 @@ utils::Duration AgcMeanLuminance::filterExposure(utils::Duration exposureValue) * * Calculate a new exposure value to try to obtain the target. The calculated * exposure value is filtered to prevent rapid changes from frame to frame, and - * divided into exposure time, analogue and digital gain. + * divided into exposure time, analogue, quantization and digital gain. * - * \return Tuple of exposure time, analogue gain, and digital gain + * \return Tuple of exposure time, analogue gain, quantization gain and digital + * gain */ -std::tuple +std::tuple AgcMeanLuminance::calculateNewEv(uint32_t constraintModeIndex, uint32_t exposureModeIndex, const Histogram &yHist, diff --git a/src/ipa/libipa/agc_mean_luminance.h b/src/ipa/libipa/agc_mean_luminance.h index a7c7e006af42..741ccf986625 100644 --- a/src/ipa/libipa/agc_mean_luminance.h +++ b/src/ipa/libipa/agc_mean_luminance.h @@ -68,7 +68,7 @@ public: return controls_; } - std::tuple + std::tuple calculateNewEv(uint32_t constraintModeIndex, uint32_t exposureModeIndex, const Histogram &yHist, utils::Duration effectiveExposureValue); diff --git a/src/ipa/libipa/exposure_mode_helper.cpp b/src/ipa/libipa/exposure_mode_helper.cpp index 7d470ebe487c..79b8e6758faf 100644 --- a/src/ipa/libipa/exposure_mode_helper.cpp +++ b/src/ipa/libipa/exposure_mode_helper.cpp @@ -178,14 +178,23 @@ double ExposureModeHelper::clampGain(double gain, double *quantizationGain) cons * required exposure, the helper falls-back to simply maximising the exposure * time first, followed by analogue gain, followed by digital gain. * - * \return Tuple of exposure time, analogue gain, and digital gain + * During the calculations the gain missed due to quantization is recorded and + * returned as quantization gain. The quantization gain is not included in the + * digital gain. So to exactly apply the given exposure, both quantization gain + * and digital gain must be applied. + * + * \return Tuple of exposure time, analogue gain, quantization gain and digital + * gain */ -std::tuple +std::tuple ExposureModeHelper::splitExposure(utils::Duration exposure) const { ASSERT(maxExposureTime_); ASSERT(maxGain_); + utils::Duration exposureTime; + double gain; + double quantGain; bool gainFixed = minGain_ == maxGain_; bool exposureTimeFixed = minExposureTime_ == maxExposureTime_; @@ -193,16 +202,20 @@ ExposureModeHelper::splitExposure(utils::Duration exposure) const * There's no point entering the loop if we cannot change either gain * nor exposure time anyway. */ - if (exposureTimeFixed && gainFixed) - return { minExposureTime_, minGain_, exposure / (minExposureTime_ * minGain_) }; + if (exposureTimeFixed && gainFixed) { + exposureTime = clampExposureTime(minExposureTime_, &quantGain); + gain = clampGain(minGain_ * quantGain, &quantGain); + + return { exposureTime, gain, quantGain, + exposure / (minExposureTime_ * minGain_ * quantGain) }; + } - utils::Duration exposureTime; double stageGain = clampGain(1.0); double lastStageGain = stageGain; - double gain; for (unsigned int stage = 0; stage < gains_.size(); stage++) { - utils::Duration stageExposureTime = clampExposureTime(exposureTimes_[stage]); + utils::Duration stageExposureTime = clampExposureTime(exposureTimes_[stage], + &quantGain); stageGain = clampGain(gains_[stage]); /* @@ -215,18 +228,20 @@ ExposureModeHelper::splitExposure(utils::Duration exposure) const /* Clamp the gain to lastStageGain and regulate exposureTime. */ if (stageExposureTime * lastStageGain >= exposure) { - exposureTime = clampExposureTime(exposure / lastStageGain); - gain = clampGain(exposure / exposureTime); + exposureTime = clampExposureTime(exposure / lastStageGain, &quantGain); + gain = clampGain((exposure / exposureTime) * quantGain, &quantGain); - return { exposureTime, gain, exposure / (exposureTime * gain) }; + return { exposureTime, gain, quantGain, + exposure / (exposureTime * gain * quantGain) }; } /* Clamp the exposureTime to stageExposureTime and regulate gain. */ if (stageExposureTime * stageGain >= exposure) { exposureTime = stageExposureTime; - gain = clampGain(exposure / exposureTime); + gain = clampGain((exposure / exposureTime) * quantGain, &quantGain); - return { exposureTime, gain, exposure / (exposureTime * gain) }; + return { exposureTime, gain, quantGain, + exposure / (exposureTime * gain * quantGain) }; } lastStageGain = stageGain; @@ -239,10 +254,11 @@ ExposureModeHelper::splitExposure(utils::Duration exposure) const * stages to use then the default stageGain of 1.0 is used so that * exposure time is maxed before gain is touched at all. */ - exposureTime = clampExposureTime(exposure / stageGain); - gain = clampGain(exposure / exposureTime); + exposureTime = clampExposureTime(exposure / stageGain, &quantGain); + gain = clampGain((exposure / exposureTime) * quantGain, &quantGain); - return { exposureTime, gain, exposure / (exposureTime * gain) }; + return { exposureTime, gain, quantGain, + exposure / (exposureTime * gain * quantGain) }; } /** diff --git a/src/ipa/libipa/exposure_mode_helper.h b/src/ipa/libipa/exposure_mode_helper.h index 8701fae9a26e..cc811e9fde18 100644 --- a/src/ipa/libipa/exposure_mode_helper.h +++ b/src/ipa/libipa/exposure_mode_helper.h @@ -30,7 +30,7 @@ public: void setLimits(utils::Duration minExposureTime, utils::Duration maxExposureTime, double minGain, double maxGain); - std::tuple + std::tuple splitExposure(utils::Duration exposure) const; utils::Duration minExposureTime() const { return minExposureTime_; } diff --git a/src/ipa/rkisp1/algorithms/agc.cpp b/src/ipa/rkisp1/algorithms/agc.cpp index 35440b67e999..0a29326841fb 100644 --- a/src/ipa/rkisp1/algorithms/agc.cpp +++ b/src/ipa/rkisp1/algorithms/agc.cpp @@ -567,15 +567,16 @@ void Agc::process(IPAContext &context, [[maybe_unused]] const uint32_t frame, setExposureCompensation(pow(2.0, frameContext.agc.exposureValue)); utils::Duration newExposureTime; - double aGain, dGain; - std::tie(newExposureTime, aGain, dGain) = + double aGain, qGain, dGain; + std::tie(newExposureTime, aGain, qGain, dGain) = calculateNewEv(frameContext.agc.constraintMode, frameContext.agc.exposureMode, hist, effectiveExposureValue); LOG(RkISP1Agc, Debug) - << "Divided up exposure time, analogue gain and digital gain are " - << newExposureTime << ", " << aGain << " and " << dGain; + << "Divided up exposure time, analogue gain, quantization gain" + << " and digital gain are " << newExposureTime << ", " << aGain + << ", " << qGain << " and " << dGain; IPAActiveState &activeState = context.activeState; /* Update the estimated exposure and gain. */