{"id":14245,"url":"https://patchwork.libcamera.org/api/patches/14245/?format=json","web_url":"https://patchwork.libcamera.org/patch/14245/","project":{"id":1,"url":"https://patchwork.libcamera.org/api/projects/1/?format=json","name":"libcamera","link_name":"libcamera","list_id":"libcamera_core","list_email":"libcamera-devel@lists.libcamera.org","web_url":"","scm_url":"","webscm_url":""},"msgid":"<20211022073249.35084-10-jeanmichel.hautbois@ideasonboard.com>","date":"2021-10-22T07:32:44","name":"[libcamera-devel,v4,09/14] ipa: ipu3: agc: Simplify division of exposure/gain","commit_ref":"17dbae2325d81f555cdaae0a631dd6435e71159b","pull_url":null,"state":"accepted","archived":false,"hash":"cc2167263aeb4c7b5d1efd56f928016291f7800b","submitter":{"id":75,"url":"https://patchwork.libcamera.org/api/people/75/?format=json","name":"Jean-Michel Hautbois","email":"jeanmichel.hautbois@ideasonboard.com"},"delegate":null,"mbox":"https://patchwork.libcamera.org/patch/14245/mbox/","series":[{"id":2647,"url":"https://patchwork.libcamera.org/api/series/2647/?format=json","web_url":"https://patchwork.libcamera.org/project/libcamera/list/?series=2647","date":"2021-10-22T07:32:35","name":"ipa: ipu3: Fix AGC bugs","version":4,"mbox":"https://patchwork.libcamera.org/series/2647/mbox/"}],"comments":"https://patchwork.libcamera.org/api/patches/14245/comments/","check":"pending","checks":"https://patchwork.libcamera.org/api/patches/14245/checks/","tags":{},"headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id 6FF37BF415\n\tfor ;\n\tFri, 22 Oct 2021 07:33:07 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 31A5C68F78;\n\tFri, 22 Oct 2021 09:33:07 +0200 (CEST)","from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 00A6B68F61\n\tfor ;\n\tFri, 22 Oct 2021 09:32:55 +0200 (CEST)","from tatooine.ideasonboard.com (unknown\n\t[IPv6:2a01:e0a:169:7140:22cc:3af6:5ccb:8367])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id A29C289A;\n\tFri, 22 Oct 2021 09:32:55 +0200 (CEST)"],"Authentication-Results":"lancelot.ideasonboard.com;\n\tdkim=fail reason=\"signature verification failed\" (1024-bit key;\n\tunprotected) header.d=ideasonboard.com header.i=@ideasonboard.com\n\theader.b=\"RjVZq14w\"; dkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1634887975;\n\tbh=XX4YejTj/2VsEWRl3/FpFC7fzwcgGBNu0KEzB+XHSX8=;\n\th=From:To:Cc:Subject:Date:In-Reply-To:References:From;\n\tb=RjVZq14wOGEezN5FyyRfN6FgQhWH2JQ1JSK/oQbchIiRIWIYqZBwDnHiVBojzq3XO\n\tgD36xiONe5TlRvoBhThsorrv858hfszMOYYHG0U6vK4oEbPLwB+0KPd2Ka64HnOAXW\n\tfCnw8wOuFS38acMSV12BNlFD/e34myKgeKfk7mGs=","From":"Jean-Michel Hautbois ","To":"libcamera-devel@lists.libcamera.org","Date":"Fri, 22 Oct 2021 09:32:44 +0200","Message-Id":"<20211022073249.35084-10-jeanmichel.hautbois@ideasonboard.com>","X-Mailer":"git-send-email 2.32.0","In-Reply-To":"<20211022073249.35084-1-jeanmichel.hautbois@ideasonboard.com>","References":"<20211022073249.35084-1-jeanmichel.hautbois@ideasonboard.com>","MIME-Version":"1.0","Content-Transfer-Encoding":"8bit","Subject":"[libcamera-devel] [PATCH v4 09/14] ipa: ipu3: agc: Simplify\n\tdivision of exposure/gain","X-BeenThere":"libcamera-devel@lists.libcamera.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "},"content":"Until now, the algorithm makes complex assumptions when dividing the\nexposure and analogue gain values. Instead, use a simpler clamping of\nthe shutter speed first, and then of the analogue gain, based on the\nlimits configured.\n\nSigned-off-by: Jean-Michel Hautbois \nReviewed-by: Laurent Pinchart \nReviewed-by: Kieran Bingham \n---\n src/ipa/ipu3/algorithms/agc.cpp | 36 +++++++++++++++++----------------\n 1 file changed, 19 insertions(+), 17 deletions(-)","diff":"diff --git a/src/ipa/ipu3/algorithms/agc.cpp b/src/ipa/ipu3/algorithms/agc.cpp\nindex f5bb3328..6f5b6a45 100644\n--- a/src/ipa/ipu3/algorithms/agc.cpp\n+++ b/src/ipa/ipu3/algorithms/agc.cpp\n@@ -147,7 +147,9 @@ void Agc::lockExposureGain(uint32_t &exposure, double &gain)\n \t\t\t\t << \" Gain \" << gain;\n \n \t\tcurrentExposure_ = currentExposureNoDg_ * newGain;\n+\t\tutils::Duration minShutterSpeed = minExposureLines_ * lineDuration_;\n \t\tutils::Duration maxShutterSpeed = maxExposureLines_ * lineDuration_;\n+\n \t\tutils::Duration maxTotalExposure = maxShutterSpeed * kMaxGain;\n \t\tcurrentExposure_ = std::min(currentExposure_, maxTotalExposure);\n \t\tLOG(IPU3Agc, Debug) << \"Target total exposure \" << currentExposure_\n@@ -156,23 +158,23 @@ void Agc::lockExposureGain(uint32_t &exposure, double &gain)\n \t\t/* \\todo: estimate if we need to desaturate */\n \t\tfilterExposure();\n \n-\t\tutils::Duration newExposure = 0.0s;\n-\t\tif (currentShutter < maxShutterSpeed) {\n-\t\t\texposure = std::clamp(exposure * filteredExposure_ / currentExposureNoDg_,\n-\t\t\t\t\t\t\tminExposureLines_,\n-\t\t\t\t\t\t\tmaxExposureLines_);\n-\t\t\tnewExposure = filteredExposure_ / exposure;\n-\t\t\tgain = std::clamp(gain * filteredExposure_ / newExposure,\n-\t\t\t\t\t kMinGain, kMaxGain);\n-\t\t} else {\n-\t\t\tgain = std::clamp(gain * filteredExposure_ / currentExposureNoDg_,\n-\t\t\t\t\t kMinGain, kMaxGain);\n-\t\t\tnewExposure = filteredExposure_ / gain;\n-\t\t\texposure = std::clamp(exposure * filteredExposure_ / newExposure,\n-\t\t\t\t\t\t\tminExposureLines_,\n-\t\t\t\t\t\t\tmaxExposureLines_);\n-\t\t}\n-\t\tLOG(IPU3Agc, Debug) << \"Adjust exposure \" << exposure * lineDuration_ << \" and gain \" << gain;\n+\t\tutils::Duration exposureValue = filteredExposure_;\n+\t\tutils::Duration shutterTime = minShutterSpeed;\n+\n+\t\t/*\n+\t\t * Push the shutter time up to the maximum first, and only then\n+\t\t * increase the gain.\n+\t\t */\n+\t\tshutterTime = std::clamp(exposureValue / kMinGain,\n+\t\t\t\t\t\t\t minShutterSpeed, maxShutterSpeed);\n+\t\tdouble stepGain = std::clamp(exposureValue / shutterTime,\n+\t\t\t\t\t kMinGain, kMaxGain);\n+\t\tLOG(IPU3Agc, Debug) << \"Divided up shutter and gain are \"\n+\t\t\t\t << shutterTime << \" and \"\n+\t\t\t\t << stepGain;\n+\n+\t\texposure = shutterTime / lineDuration_;\n+\t\tgain = stepGain;\n \t}\n \tlastFrame_ = frameCount_;\n }\n","prefixes":["libcamera-devel","v4","09/14"]}