{"id":26595,"url":"https://patchwork.libcamera.org/api/patches/26595/?format=json","web_url":"https://patchwork.libcamera.org/patch/26595/","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":"<20260501191400.985920-4-devve.3@gmail.com>","date":"2026-05-01T19:13:12","name":"ipa: simple: agc: Read exposure target and gain from YAML","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"f36406881a44b7ff9b571f3833512455d8eac4f1","submitter":{"id":271,"url":"https://patchwork.libcamera.org/api/people/271/?format=json","name":"devve","email":"devve.3@gmail.com"},"delegate":null,"mbox":"https://patchwork.libcamera.org/patch/26595/mbox/","series":[{"id":5896,"url":"https://patchwork.libcamera.org/api/series/5896/?format=json","web_url":"https://patchwork.libcamera.org/project/libcamera/list/?series=5896","date":"2026-05-01T19:13:12","name":"ipa: simple: agc: Read exposure target and gain from YAML","version":1,"mbox":"https://patchwork.libcamera.org/series/5896/mbox/"}],"comments":"https://patchwork.libcamera.org/api/patches/26595/comments/","check":"pending","checks":"https://patchwork.libcamera.org/api/patches/26595/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 47B7AC32F7\n\tfor ;\n\tFri, 1 May 2026 19:55:31 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 7B8BC63020;\n\tFri, 1 May 2026 21:55:28 +0200 (CEST)","from mail-wm1-x332.google.com (mail-wm1-x332.google.com\n\t[IPv6:2a00:1450:4864:20::332])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id E5A106301A\n\tfor ;\n\tFri, 1 May 2026 21:14:24 +0200 (CEST)","by mail-wm1-x332.google.com with SMTP id\n\t5b1f17b1804b1-488ab2db91aso25729605e9.3\n\tfor ;\n\tFri, 01 May 2026 12:14:24 -0700 (PDT)","from dexps.speedport.ip\n\t(p200300eda74453f7a35e44f7d2f0427a.dip0.t-ipconnect.de.\n\t[2003:ed:a744:53f7:a35e:44f7:d2f0:427a])\n\tby smtp.gmail.com with ESMTPSA id\n\t5b1f17b1804b1-48a8eb69698sm139146305e9.1.2026.05.01.12.14.23\n\t(version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256);\n\tFri, 01 May 2026 12:14:24 -0700 (PDT)"],"Authentication-Results":"lancelot.ideasonboard.com; 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\n\tFri, 01 May 2026 12:14:24 -0700 (PDT)","From":"d3vv3 ","To":"libcamera-devel@lists.libcamera.org","Cc":"d3vv3 ","Subject":"[PATCH] ipa: simple: agc: Read exposure target and gain from YAML","Date":"Fri, 1 May 2026 21:13:12 +0200","Message-ID":"<20260501191400.985920-4-devve.3@gmail.com>","X-Mailer":"git-send-email 2.54.0","In-Reply-To":"<20260501191400.985920-1-devve.3@gmail.com>","References":"<20260501191400.985920-1-devve.3@gmail.com>","MIME-Version":"1.0","Content-Transfer-Encoding":"8bit","X-Mailman-Approved-At":"Fri, 01 May 2026 21:55:24 +0200","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":"Replace the hardcoded kExposureOptimal, kExposureSatisfactory, and\nkExpProportionalGain constants with member variables read from the\ntuning file as exposureTarget, hysteresis, and proportionalGain.\nDefaults match the previous values (2.5, 0.2, 0.04).\n\nSigned-off-by: d3vv3 \n---\n src/ipa/simple/algorithms/agc.cpp | 33 ++++++++++++++++++++-----------\n src/ipa/simple/algorithms/agc.h | 8 ++++++++\n 2 files changed, 30 insertions(+), 11 deletions(-)","diff":"diff --git a/src/ipa/simple/algorithms/agc.cpp b/src/ipa/simple/algorithms/agc.cpp\nindex ac977d5f..66618d0f 100644\n--- a/src/ipa/simple/algorithms/agc.cpp\n+++ b/src/ipa/simple/algorithms/agc.cpp\n@@ -28,45 +28,56 @@ static constexpr unsigned int kExposureBinsCount = 5;\n \n /*\n * The exposure is optimal when the mean sample value of the histogram is\n- * in the middle of the range.\n+ * in the middle of the range. Overridable via YAML exposureTarget.\n */\n-static constexpr float kExposureOptimal = kExposureBinsCount / 2.0;\n+static constexpr float kExposureTargetDefault = kExposureBinsCount / 2.0;\n \n /*\n * This implements the hysteresis for the exposure adjustment.\n * It is small enough to have the exposure close to the optimal, and is big\n * enough to prevent the exposure from wobbling around the optimal value.\n */\n-static constexpr float kExposureSatisfactory = 0.2;\n+static constexpr float kHysteresisDefault = 0.2;\n \n /*\n * Proportional gain for exposure/gain adjustment. Maps the MSV error to a\n * multiplicative correction factor:\n *\n- * factor = 1.0 + kExpProportionalGain * error\n+ * factor = 1.0 + proportionalGain_ * error\n *\n- * With kExpProportionalGain = 0.04:\n+ * With proportionalGain_ = 0.04:\n * - max error ~2.5 -> factor 1.10 (~10% step, same as before)\n * - error 1.0 -> factor 1.04 (~4% step)\n * - error 0.3 -> factor 1.012 (~1.2% step)\n *\n- * This replaces the fixed 10% bang-bang step with a proportional correction\n- * that converges smoothly and avoids overshooting near the target.\n+ * Overridable via YAML proportionalGain.\n */\n-static constexpr float kExpProportionalGain = 0.04;\n+static constexpr float kProportionalGainDefault = 0.04;\n \n Agc::Agc()\n {\n }\n \n+int Agc::init([[maybe_unused]] IPAContext &context, const ValueNode &tuningData)\n+{\n+\texposureTarget_ = tuningData[\"exposureTarget\"].get()\n+\t\t.value_or(kExposureTargetDefault);\n+\thysteresis_ = tuningData[\"hysteresis\"].get()\n+\t\t.value_or(kHysteresisDefault);\n+\tproportionalGain_ = tuningData[\"proportionalGain\"].get()\n+\t\t.value_or(kProportionalGainDefault);\n+\n+\treturn 0;\n+}\n+\n void Agc::updateExposure(IPAContext &context, IPAFrameContext &frameContext, double exposureMSV)\n {\n \tint32_t &exposure = frameContext.sensor.exposure;\n \tdouble &again = frameContext.sensor.gain;\n \n-\tdouble error = kExposureOptimal - exposureMSV;\n+\tdouble error = exposureTarget_ - exposureMSV;\n \n-\tif (std::abs(error) <= kExposureSatisfactory)\n+\tif (std::abs(error) <= hysteresis_)\n \t\treturn;\n \n \t/*\n@@ -74,7 +85,7 @@ void Agc::updateExposure(IPAContext &context, IPAFrameContext &frameContext, dou\n \t * determines the direction: positive error means too dark (increase),\n \t * negative means too bright (decrease).\n \t */\n-\tfloat factor = 1.0f + static_cast(error) * kExpProportionalGain;\n+\tfloat factor = 1.0f + static_cast(error) * proportionalGain_;\n \n \tif (factor > 1.0f) {\n \t\t/* Scene too dark: increase exposure first, then gain. */\ndiff --git a/src/ipa/simple/algorithms/agc.h b/src/ipa/simple/algorithms/agc.h\nindex 112d9f5a..b8ed542b 100644\n--- a/src/ipa/simple/algorithms/agc.h\n+++ b/src/ipa/simple/algorithms/agc.h\n@@ -7,6 +7,8 @@\n \n #pragma once\n \n+#include \n+\n #include \"algorithm.h\"\n \n namespace libcamera {\n@@ -19,6 +21,8 @@ public:\n \tAgc();\n \t~Agc() = default;\n \n+\tint init(IPAContext &context, const ValueNode &tuningData) override;\n+\n \tvoid process(IPAContext &context, const uint32_t frame,\n \t\t IPAFrameContext &frameContext,\n \t\t const SwIspStats *stats,\n@@ -26,6 +30,10 @@ public:\n \n private:\n \tvoid updateExposure(IPAContext &context, IPAFrameContext &frameContext, double exposureMSV);\n+\n+\tfloat exposureTarget_;\n+\tfloat hysteresis_;\n+\tfloat proportionalGain_;\n };\n \n } /* namespace ipa::soft::algorithms */\n","prefixes":[]}