{"id":21826,"url":"https://patchwork.libcamera.org/api/patches/21826/?format=json","web_url":"https://patchwork.libcamera.org/patch/21826/","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":"<20241107102508.48322-2-dan.scally@ideasonboard.com>","date":"2024-11-07T10:25:03","name":"[v2,1/6] ipa: libipa: Add miscellaneous helpers","commit_ref":null,"pull_url":null,"state":"superseded","archived":false,"hash":"fc78e06eca8d728c5f7106bf022b792bbd7a27ce","submitter":{"id":156,"url":"https://patchwork.libcamera.org/api/people/156/?format=json","name":"Dan Scally","email":"dan.scally@ideasonboard.com"},"delegate":null,"mbox":"https://patchwork.libcamera.org/patch/21826/mbox/","series":[{"id":4775,"url":"https://patchwork.libcamera.org/api/series/4775/?format=json","web_url":"https://patchwork.libcamera.org/project/libcamera/list/?series=4775","date":"2024-11-07T10:25:03","name":"Centralise common functions in IPA modules","version":2,"mbox":"https://patchwork.libcamera.org/series/4775/mbox/"}],"comments":"https://patchwork.libcamera.org/api/patches/21826/comments/","check":"pending","checks":"https://patchwork.libcamera.org/api/patches/21826/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 64535BDB13\n\tfor ;\n\tThu, 7 Nov 2024 10:25:28 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 7BDD565472;\n\tThu, 7 Nov 2024 11:25:27 +0100 (CET)","from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[213.167.242.64])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id A8DCE65458\n\tfor ;\n\tThu, 7 Nov 2024 11:25:24 +0100 (CET)","from mail.ideasonboard.com\n\t(cpc141996-chfd3-2-0-cust928.12-3.cable.virginm.net [86.13.91.161])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id 9A51E792;\n\tThu, 7 Nov 2024 11:25:15 +0100 (CET)"],"Authentication-Results":"lancelot.ideasonboard.com; dkim=pass (1024-bit key;\n\tunprotected) header.d=ideasonboard.com header.i=@ideasonboard.com\n\theader.b=\"tcpDee4F\"; dkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1730975115;\n\tbh=e3ObU7OE9RcDVUOjXAfun32JwxITj7W0LOafdKOatxc=;\n\th=From:To:Cc:Subject:Date:In-Reply-To:References:From;\n\tb=tcpDee4FmwZMhUcgyEtNh9csYrQy+RScjx5Kd2GmVgVOCqGDS/gFR2P/V8kPJN5QJ\n\tk+LkLHNusCSBZzzwPEF36wz6SMerXZQci3O9pggj/i8N3GILnKVrxMGZWXX+HoqxDC\n\t5wZkM22i1Id31z4C7v+E/hg1iijJuEHJ42UbppTY=","From":"Daniel Scally ","To":"libcamera-devel@lists.libcamera.org","Cc":"mike.rudenko@gmail.com,\n\tDaniel Scally ","Subject":"[PATCH v2 1/6] ipa: libipa: Add miscellaneous helpers","Date":"Thu, 7 Nov 2024 10:25:03 +0000","Message-Id":"<20241107102508.48322-2-dan.scally@ideasonboard.com>","X-Mailer":"git-send-email 2.34.1","In-Reply-To":"<20241107102508.48322-1-dan.scally@ideasonboard.com>","References":"<20241107102508.48322-1-dan.scally@ideasonboard.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":"We start to have functions that are effectively identical crop up\nacross the IPA modules. Add a file allowing those to be centralised\nwithin libipa so that a single implementation can be used in all of\nthe IPAs.\n\nSigned-off-by: Daniel Scally \n---\nChanges in v2:\n\n\t- Dropped the Q(m, n) format helpers until they're needed.\n\t- \\return statements after long description\n\t- Switched rec601LuminanceFromRGB() to return a double\n\n src/ipa/libipa/helpers.cpp | 77 ++++++++++++++++++++++++++++++++++++++\n src/ipa/libipa/helpers.h | 21 +++++++++++\n src/ipa/libipa/meson.build | 2 +\n 3 files changed, 100 insertions(+)\n create mode 100644 src/ipa/libipa/helpers.cpp\n create mode 100644 src/ipa/libipa/helpers.h","diff":"diff --git a/src/ipa/libipa/helpers.cpp b/src/ipa/libipa/helpers.cpp\nnew file mode 100644\nindex 00000000..6c038895\n--- /dev/null\n+++ b/src/ipa/libipa/helpers.cpp\n@@ -0,0 +1,77 @@\n+/* SPDX-License-Identifier: BSD-2-Clause */\n+/*\n+ * Copyright (C) 2024, Ideas on Board Oy\n+ *\n+ * libipa miscellaneous helpers\n+ */\n+\n+#include \"helpers.h\"\n+\n+#include \n+#include \n+\n+namespace libcamera {\n+\n+namespace ipa {\n+\n+/**\n+ * \\file helpers.h\n+ * \\brief Functions to reduce code duplication between IPA modules\n+ */\n+\n+/**\n+ * \\brief Estimate luminance from RGB values following ITU-R BT.601\n+ * \\param[in] r The red value\n+ * \\param[in] g The green value\n+ * \\param[in] b The blue value\n+ *\n+ * This function estimates a luminance value from a triplet of Red, Green and\n+ * Blue values, following the formula defined by ITU-R Recommendation BT.601-7\n+ * which can be found at https://www.itu.int/rec/R-REC-BT.601\n+ *\n+ * \\return The estimated luminance value\n+ */\n+double rec601LuminanceFromRGB(unsigned int r, unsigned int g, unsigned int b)\n+{\n+\treturn (r * .299) + (g * .587) + (b * .114);\n+}\n+\n+/**\n+ * \\brief Estimate correlated colour temperature from RGB color space input\n+ * \\param[in] red The input red value\n+ * \\param[in] green The input green value\n+ * \\param[in] blue The input blue value\n+ *\n+ * This function estimates the correlated color temperature RGB color space\n+ * input. In physics and color science, the Planckian locus or black body locus\n+ * is the path or locus that the color of an incandescent black body would take\n+ * in a particular chromaticity space as the blackbody temperature changes.\n+ *\n+ * If a narrow range of color temperatures is considered (those encapsulating\n+ * daylight being the most practical case) one can approximate the Planckian\n+ * locus in order to calculate the CCT in terms of chromaticity coordinates.\n+ *\n+ * More detailed information can be found in:\n+ * https://en.wikipedia.org/wiki/Color_temperature#Approximation\n+ *\n+ * \\return The estimated color temperature\n+ */\n+uint32_t estimateCCT(double red, double green, double blue)\n+{\n+\t/* Convert the RGB values to CIE tristimulus values (XYZ) */\n+\tdouble X = (-0.14282) * (red) + (1.54924) * (green) + (-0.95641) * (blue);\n+\tdouble Y = (-0.32466) * (red) + (1.57837) * (green) + (-0.73191) * (blue);\n+\tdouble Z = (-0.68202) * (red) + (0.77073) * (green) + (0.56332) * (blue);\n+\n+\t/* Calculate the normalized chromaticity values */\n+\tdouble x = X / (X + Y + Z);\n+\tdouble y = Y / (X + Y + Z);\n+\n+\t/* Calculate CCT */\n+\tdouble n = (x - 0.3320) / (0.1858 - y);\n+\treturn 449 * n * n * n + 3525 * n * n + 6823.3 * n + 5520.33;\n+}\n+\n+} /* namespace ipa */\n+\n+} /* namespace libcamera */\ndiff --git a/src/ipa/libipa/helpers.h b/src/ipa/libipa/helpers.h\nnew file mode 100644\nindex 00000000..51c74a36\n--- /dev/null\n+++ b/src/ipa/libipa/helpers.h\n@@ -0,0 +1,21 @@\n+/* SPDX-License-Identifier: BSD-2-Clause */\n+/*\n+ * Copyright (C) 2024, Ideas on Board Oy\n+ *\n+ * libipa miscellaneous helpers\n+ */\n+\n+#pragma once\n+\n+#include \n+\n+namespace libcamera {\n+\n+namespace ipa {\n+\n+double rec601LuminanceFromRGB(unsigned int r, unsigned int g, unsigned int b);\n+uint32_t estimateCCT(double red, double green, double blue);\n+\n+} /* namespace ipa */\n+\n+} /* namespace libcamera */\ndiff --git a/src/ipa/libipa/meson.build b/src/ipa/libipa/meson.build\nindex e78cbcd6..ca4f3e28 100644\n--- a/src/ipa/libipa/meson.build\n+++ b/src/ipa/libipa/meson.build\n@@ -6,6 +6,7 @@ libipa_headers = files([\n 'camera_sensor_helper.h',\n 'exposure_mode_helper.h',\n 'fc_queue.h',\n+ 'helpers.h',\n 'histogram.h',\n 'interpolator.h',\n 'lsc_polynomial.h',\n@@ -21,6 +22,7 @@ libipa_sources = files([\n 'camera_sensor_helper.cpp',\n 'exposure_mode_helper.cpp',\n 'fc_queue.cpp',\n+ 'helpers.cpp',\n 'histogram.cpp',\n 'interpolator.cpp',\n 'lsc_polynomial.cpp',\n","prefixes":["v2","1/6"]}