{"id":23610,"url":"https://patchwork.libcamera.org/api/patches/23610/?format=json","web_url":"https://patchwork.libcamera.org/patch/23610/","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":"<20250620124452.557855-3-naush@raspberrypi.com>","date":"2025-06-20T12:42:23","name":"[v1,2/8] ipa: rpi: controller: Improve findPeak() function in AF algorithm","commit_ref":null,"pull_url":null,"state":"accepted","archived":false,"hash":"311a5c6fde40123015d803b0271ecbb42889f2d2","submitter":{"id":34,"url":"https://patchwork.libcamera.org/api/people/34/?format=json","name":"Naushir Patuck","email":"naush@raspberrypi.com"},"delegate":null,"mbox":"https://patchwork.libcamera.org/patch/23610/mbox/","series":[{"id":5235,"url":"https://patchwork.libcamera.org/api/series/5235/?format=json","web_url":"https://patchwork.libcamera.org/project/libcamera/list/?series=5235","date":"2025-06-20T12:42:21","name":"Raspberry Pi: AF improvements","version":1,"mbox":"https://patchwork.libcamera.org/series/5235/mbox/"}],"comments":"https://patchwork.libcamera.org/api/patches/23610/comments/","check":"pending","checks":"https://patchwork.libcamera.org/api/patches/23610/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 5477DBDE6B\n\tfor ;\n\tFri, 20 Jun 2025 12:45:09 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 77F8B61535;\n\tFri, 20 Jun 2025 14:45:06 +0200 (CEST)","from mail-wr1-x42f.google.com (mail-wr1-x42f.google.com\n\t[IPv6:2a00:1450:4864:20::42f])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 2C39E61535\n\tfor ;\n\tFri, 20 Jun 2025 14:44:59 +0200 (CEST)","by mail-wr1-x42f.google.com with SMTP id\n\tffacd0b85a97d-3a4e749d7b2so353163f8f.0\n\tfor ;\n\tFri, 20 Jun 2025 05:44:59 -0700 (PDT)","from NAUSH-P-DELL.pitowers.org ([93.93.133.154])\n\tby smtp.gmail.com with ESMTPSA id\n\t5b1f17b1804b1-45361461375sm41561525e9.14.2025.06.20.05.44.58\n\t(version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256);\n\tFri, 20 Jun 2025 05:44:58 -0700 (PDT)"],"Authentication-Results":"lancelot.ideasonboard.com; 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\n\tFri, 20 Jun 2025 05:44:58 -0700 (PDT)","From":"Naushir Patuck ","To":"libcamera-devel@lists.libcamera.org","Cc":"Nick Hollinghurst ,\n\tNaushir Patuck ","Subject":"[PATCH v1 2/8] ipa: rpi: controller: Improve findPeak() function in\n\tAF algorithm","Date":"Fri, 20 Jun 2025 13:42:23 +0100","Message-ID":"<20250620124452.557855-3-naush@raspberrypi.com>","X-Mailer":"git-send-email 2.43.0","In-Reply-To":"<20250620124452.557855-1-naush@raspberrypi.com>","References":"<20250620124452.557855-1-naush@raspberrypi.com>","MIME-Version":"1.0","Content-Transfer-Encoding":"8bit","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":"From: Nick Hollinghurst \n\nImprove quadratic peak fitting in findPeak(). The old approximation\nwas good but only valid when points were equally spaced and the\nMAX was not at one end of the series.\n\nSigned-off-by: Nick Hollinghurst \nSigned-off-by: Naushir Patuck \nReviewed-by: Naushir Patuck \n---\n src/ipa/rpi/controller/rpi/af.cpp | 31 ++++++++++++++++++++++---------\n 1 file changed, 22 insertions(+), 9 deletions(-)","diff":"diff --git a/src/ipa/rpi/controller/rpi/af.cpp b/src/ipa/rpi/controller/rpi/af.cpp\nindex 041cb51db277..8df614ed7b6b 100644\n--- a/src/ipa/rpi/controller/rpi/af.cpp\n+++ b/src/ipa/rpi/controller/rpi/af.cpp\n@@ -436,15 +436,28 @@ double Af::findPeak(unsigned i) const\n {\n \tdouble f = scanData_[i].focus;\n \n-\tif (i > 0 && i + 1 < scanData_.size()) {\n-\t\tdouble dropLo = scanData_[i].contrast - scanData_[i - 1].contrast;\n-\t\tdouble dropHi = scanData_[i].contrast - scanData_[i + 1].contrast;\n-\t\tif (0.0 <= dropLo && dropLo < dropHi) {\n-\t\t\tdouble param = 0.3125 * (1.0 - dropLo / dropHi) * (1.6 - dropLo / dropHi);\n-\t\t\tf += param * (scanData_[i - 1].focus - f);\n-\t\t} else if (0.0 <= dropHi && dropHi < dropLo) {\n-\t\t\tdouble param = 0.3125 * (1.0 - dropHi / dropLo) * (1.6 - dropHi / dropLo);\n-\t\t\tf += param * (scanData_[i + 1].focus - f);\n+\tif (scanData_.size() >= 3) {\n+\t\t/*\n+\t\t * Given the sample with the highest contrast score and its two\n+\t\t * neighbours either side (or same side if at the end of a scan),\n+\t\t * solve for the best lens position by fitting a parabola.\n+\t\t * Adapted from awb.cpp: interpolateQaudaratic()\n+\t\t */\n+\n+\t\tif (i == 0)\n+\t\t\ti++;\n+\t\telse if (i + 1 >= scanData_.size())\n+\t\t\ti--;\n+\n+\t\tdouble abx = scanData_[i - 1].focus - scanData_[i].focus;\n+\t\tdouble aby = scanData_[i - 1].contrast - scanData_[i].contrast;\n+\t\tdouble cbx = scanData_[i + 1].focus - scanData_[i].focus;\n+\t\tdouble cby = scanData_[i + 1].contrast - scanData_[i].contrast;\n+\t\tdouble denom = 2.0 * (aby * cbx - cby * abx);\n+\t\tif (std::abs(denom) >= (1.0 / 64.0) && denom * abx > 0.0) {\n+\t\t\tf = (aby * cbx * cbx - cby * abx * abx) / denom;\n+\t\t\tf = std::clamp(f, std::min(abx, cbx), std::max(abx, cbx));\n+\t\t\tf += scanData_[i].focus;\n \t\t}\n \t}\n \n","prefixes":["v1","2/8"]}