{"id":10438,"url":"https://patchwork.libcamera.org/api/patches/10438/?format=json","web_url":"https://patchwork.libcamera.org/patch/10438/","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":"<20201116164918.2055-10-david.plowman@raspberrypi.com>","date":"2020-11-16T16:49:17","name":"[libcamera-devel,09/10] libcamera: src: ipa: raspberrypi: agc: Improve gain update calculation for partly saturated images","commit_ref":null,"pull_url":null,"state":"superseded","archived":false,"hash":"c841bda91c7e4fca0c2877cf948a1fadcb5c0499","submitter":{"id":42,"url":"https://patchwork.libcamera.org/api/people/42/?format=json","name":"David Plowman","email":"david.plowman@raspberrypi.com"},"delegate":null,"mbox":"https://patchwork.libcamera.org/patch/10438/mbox/","series":[{"id":1464,"url":"https://patchwork.libcamera.org/api/series/1464/?format=json","web_url":"https://patchwork.libcamera.org/project/libcamera/list/?series=1464","date":"2020-11-16T16:49:08","name":"Raspberry Pi AGC","version":1,"mbox":"https://patchwork.libcamera.org/series/1464/mbox/"}],"comments":"https://patchwork.libcamera.org/api/patches/10438/comments/","check":"pending","checks":"https://patchwork.libcamera.org/api/patches/10438/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 915CDBE088\n\tfor ;\n\tMon, 16 Nov 2020 16:49:38 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 5C9C0632DC;\n\tMon, 16 Nov 2020 17:49:38 +0100 (CET)","from mail-wr1-x42b.google.com (mail-wr1-x42b.google.com\n\t[IPv6:2a00:1450:4864:20::42b])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 706F1632E2\n\tfor ;\n\tMon, 16 Nov 2020 17:49:33 +0100 (CET)","by mail-wr1-x42b.google.com with SMTP id k2so19457248wrx.2\n\tfor ;\n\tMon, 16 Nov 2020 08:49:33 -0800 (PST)","from pi4-davidp.lan (plowpeople3.plus.com. [80.229.223.72])\n\tby smtp.gmail.com with ESMTPSA id\n\tq16sm23716973wrn.13.2020.11.16.08.49.32\n\t(version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256);\n\tMon, 16 Nov 2020 08:49:32 -0800 (PST)"],"Authentication-Results":"lancelot.ideasonboard.com;\n\tdkim=fail reason=\"signature verification failed\" (2048-bit key;\n\tunprotected) header.d=raspberrypi.com header.i=@raspberrypi.com\n\theader.b=\"Rgg51cvT\"; dkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/relaxed;\n\td=raspberrypi.com; s=google;\n\th=from:to:cc:subject:date:message-id:in-reply-to:references\n\t:mime-version:content-transfer-encoding;\n\tbh=Jr6QAPf1iUIZbFIQfkDfohO+vSzKEvj6JIaoOlTvUoc=;\n\tb=Rgg51cvTaovB8Dp6I780n9mCSQwyLhqIqRHL4gBJdQXWdPe/rXRiceR4U95RYXiz1R\n\tCrCicfSbPevVWq23m6uEVZHaUuZrBhOnJb/3Fx2K2rfn+rv1hbXakrwlImwOVj10W6BK\n\tSKLrOyj3X32Q8JTWtSqNZwqkYgoMnY40XnfgcopI3kap+/n+CNmdA8WPtSo8d/5ZxkI5\n\tk10SuBJGbRvAyZu2AgOPyO8ArJT8pV6/kNE1HDP5obMHoDsINu4h5ookO+JU+l2nUwUK\n\tt2T4i6hSzT17jbMBz9MIsOiqqOyIcQEzPo/LV3vA5frsACTDvVmIQwtp9yOaVg4P3bm9\n\tgoLw==","X-Google-DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/relaxed;\n\td=1e100.net; s=20161025;\n\th=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to\n\t:references:mime-version:content-transfer-encoding;\n\tbh=Jr6QAPf1iUIZbFIQfkDfohO+vSzKEvj6JIaoOlTvUoc=;\n\tb=JxPL6RGrxjxyjDso9uvaOaRqw5anIpwMvVk19uBgK2xPbECY2Qd5LS0EPlo1SnBw/n\n\tGV1bNzO3ewNgjrS8Ym0KWbBMlI+dC6jNTf6n0b8SmpInOwNWu8gHMmQ1CKRUZ/s9a3Dv\n\t4zXm5GlBnq0IdIfqekDLB3prVQSEz5tJ+P+nVK4k42bhLeePu42QhbcF3RMgShv/URIO\n\tKnz6o1MDA9R1eHgBHRH4swAJacEJY1Gj7fxpsRMb+7wGubsWcvgo8V/IsBPFxhwTHJQk\n\tskJJPJ2TDoVdczlVn1d+Dnw2ThBVZ0HNveddQ7xJa0n9bylkhb2hbl3GqIRFbbHepOXx\n\tjCCg==","X-Gm-Message-State":"AOAM531g33PAiljWdQJeksCuHQ44DeDvy+hhiUeCbb+d7LeDEtUMA25M\n\toqtyF2Zo1qF1eiQBSchnuxkv0Fsq/qNiow==","X-Google-Smtp-Source":"ABdhPJwgfcxfcDUiDhnMMUwPAGuu/kiRsxNvwNoYcjiE7axU39hApTG1MhkH3TwID8F7cCHu2NTxfw==","X-Received":"by 2002:a5d:698c:: with SMTP id\n\tg12mr20066181wru.36.1605545372908; \n\tMon, 16 Nov 2020 08:49:32 -0800 (PST)","From":"David Plowman ","To":"libcamera-devel@lists.libcamera.org","Date":"Mon, 16 Nov 2020 16:49:17 +0000","Message-Id":"<20201116164918.2055-10-david.plowman@raspberrypi.com>","X-Mailer":"git-send-email 2.20.1","In-Reply-To":"<20201116164918.2055-1-david.plowman@raspberrypi.com>","References":"<20201116164918.2055-1-david.plowman@raspberrypi.com>","MIME-Version":"1.0","Subject":"[libcamera-devel] [PATCH 09/10] libcamera: src: ipa: raspberrypi:\n\tagc: Improve gain update calculation for partly saturated images","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","Content-Type":"text/plain; charset=\"us-ascii\"","Content-Transfer-Encoding":"7bit","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "},"content":"When parts of an image saturate then the image brightness no longer\nincreases linearly with increased exposure/gain. Having calculated a\nlinear gain value it's better then to try it, allowing for saturating\nregions, and if necessary increase the gain some more. We repeat this\nseveral times.\n\nSigned-off-by: David Plowman \n---\n src/ipa/raspberrypi/controller/rpi/agc.cpp | 34 +++++++++++++++-------\n 1 file changed, 24 insertions(+), 10 deletions(-)","diff":"diff --git a/src/ipa/raspberrypi/controller/rpi/agc.cpp b/src/ipa/raspberrypi/controller/rpi/agc.cpp\nindex 1037f968..93b46a28 100644\n--- a/src/ipa/raspberrypi/controller/rpi/agc.cpp\n+++ b/src/ipa/raspberrypi/controller/rpi/agc.cpp\n@@ -422,17 +422,21 @@ void Agc::fetchAwbStatus(Metadata *image_metadata)\n }\n \n static double compute_initial_Y(bcm2835_isp_stats *stats, AwbStatus const &awb,\n-\t\t\t\tdouble weights[])\n+\t\t\t\tdouble weights[], double gain)\n {\n \tbcm2835_isp_stats_region *regions = stats->agc_stats;\n \t// Note how the calculation below means that equal weights give you\n \t// \"average\" metering (i.e. all pixels equally important).\n \tdouble R_sum = 0, G_sum = 0, B_sum = 0, pixel_sum = 0;\n \tfor (int i = 0; i < AGC_STATS_SIZE; i++) {\n-\t\tR_sum += regions[i].r_sum * weights[i];\n-\t\tG_sum += regions[i].g_sum * weights[i];\n-\t\tB_sum += regions[i].b_sum * weights[i];\n-\t\tpixel_sum += regions[i].counted * weights[i];\n+\t\tdouble counted = regions[i].counted;\n+\t\tdouble r_sum = std::min(regions[i].r_sum * gain, ((1 << PIPELINE_BITS) - 1) * counted);\n+\t\tdouble g_sum = std::min(regions[i].g_sum * gain, ((1 << PIPELINE_BITS) - 1) * counted);\n+\t\tdouble b_sum = std::min(regions[i].b_sum * gain, ((1 << PIPELINE_BITS) - 1) * counted);\n+\t\tR_sum += r_sum * weights[i];\n+\t\tG_sum += g_sum * weights[i];\n+\t\tB_sum += b_sum * weights[i];\n+\t\tpixel_sum += counted * weights[i];\n \t}\n \tif (pixel_sum == 0.0) {\n \t\tLOG(RPiAgc, Warning) << \"compute_initial_Y: pixel_sum is zero\";\n@@ -476,11 +480,21 @@ void Agc::computeGain(bcm2835_isp_stats *statistics, Metadata *image_metadata,\n \ttarget_Y =\n \t\tconfig_.Y_target.Eval(config_.Y_target.Domain().Clip(lux.lux));\n \ttarget_Y = std::min(EV_GAIN_Y_TARGET_LIMIT, target_Y * ev_gain);\n-\tdouble initial_Y = compute_initial_Y(statistics, awb_,\n-\t\t\t\t\t metering_mode_->weights);\n-\tgain = std::min(10.0, target_Y / (initial_Y + .001));\n-\tLOG(RPiAgc, Debug) << \"Initially Y \" << initial_Y << \" target \" << target_Y\n-\t\t\t << \" gives gain \" << gain;\n+\n+\t// Do this calculation a few times as brightness increase can be\n+\t// non-linear when there are saturated regions.\n+\tgain = 1.0;\n+\tfor (int i = 0; i < 8; i++) {\n+\t\tdouble initial_Y = compute_initial_Y(statistics, awb_,\n+\t\t\t\t\t\t metering_mode_->weights, gain);\n+\t\tdouble extra_gain = std::min(10.0, target_Y / (initial_Y + .001));\n+\t\tgain *= extra_gain;\n+\t\tLOG(RPiAgc, Debug) << \"Initial Y \" << initial_Y << \" target \" << target_Y\n+\t\t\t\t << \" gives gain \" << gain;\n+\t\tif (extra_gain < 1.01) // close enough\n+\t\t\tbreak;\n+\t}\n+\n \tfor (auto &c : *constraint_mode_) {\n \t\tdouble new_target_Y;\n \t\tdouble new_gain =\n","prefixes":["libcamera-devel","09/10"]}