{"id":21897,"url":"https://patchwork.libcamera.org/api/1.1/patches/21897/?format=json","web_url":"https://patchwork.libcamera.org/patch/21897/","project":{"id":1,"url":"https://patchwork.libcamera.org/api/1.1/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":"<20241115074628.417215-2-dan.scally@ideasonboard.com>","date":"2024-11-15T07:46:23","name":"[v3,1/6] ipa: libipa: Add colour helpers","commit_ref":null,"pull_url":null,"state":"accepted","archived":false,"hash":"3a433631e2daae2b46e2b0986c2ad0e8ce050d28","submitter":{"id":156,"url":"https://patchwork.libcamera.org/api/1.1/people/156/?format=json","name":"Dan Scally","email":"dan.scally@ideasonboard.com"},"delegate":null,"mbox":"https://patchwork.libcamera.org/patch/21897/mbox/","series":[{"id":4792,"url":"https://patchwork.libcamera.org/api/1.1/series/4792/?format=json","web_url":"https://patchwork.libcamera.org/project/libcamera/list/?series=4792","date":"2024-11-15T07:46:22","name":"Centralise common functions in IPA modules","version":3,"mbox":"https://patchwork.libcamera.org/series/4792/mbox/"}],"comments":"https://patchwork.libcamera.org/api/patches/21897/comments/","check":"pending","checks":"https://patchwork.libcamera.org/api/patches/21897/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 4DEB5C0F1B\n\tfor ;\n\tFri, 15 Nov 2024 07:46:55 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id AA91A6586A;\n\tFri, 15 Nov 2024 08:46:51 +0100 (CET)","from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[213.167.242.64])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 9E14B6584E\n\tfor ;\n\tFri, 15 Nov 2024 08:46:48 +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 45FCC55;\n\tFri, 15 Nov 2024 08:46:33 +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=\"iLQRkE0F\"; dkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1731656793;\n\tbh=tb/oYz+8E680gPSRWmmqn5/zAMFkysuKilhimQHGIAc=;\n\th=From:To:Cc:Subject:Date:In-Reply-To:References:From;\n\tb=iLQRkE0Feocz8ljiKCHQM75Ag5YRipAbEldh6lOsVM1kHh/W4RJ2XQnQ1UPx+9o/l\n\tVQoR8Io7bIfDt5dsk1b3w0X++HlBVqCsT59ZyESJiJj7TozcmfqHIPNoPdpqiT8TWc\n\tMC/GYZx6abRfpqNOQ2mY54PTPq/xDHfce8M1rFx8=","From":"Daniel Scally ","To":"libcamera-devel@lists.libcamera.org","Cc":"mike.rudenko@gmail.com,\n\tDaniel Scally ","Subject":"[PATCH v3 1/6] ipa: libipa: Add colour helpers","Date":"Fri, 15 Nov 2024 07:46:23 +0000","Message-Id":"<20241115074628.417215-2-dan.scally@ideasonboard.com>","X-Mailer":"git-send-email 2.34.1","In-Reply-To":"<20241115074628.417215-1-dan.scally@ideasonboard.com>","References":"<20241115074628.417215-1-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 some functions relating to colour that are\neffectively identical crop up across the IPA modules. Add a file\nallowing those to be centralised within libipa so that a single\nimplementation can be used in all of the IPAs.\n\nSigned-off-by: Daniel Scally \n---\nChanges in v3:\n\n\t- Named the file \"colours.h\" and \"colours.cpp\" instead of \"helpers\"\n\t- Made the rec601LuminanceFromRGB() arguments doubles\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/colours.cpp | 77 ++++++++++++++++++++++++++++++++++++++\n src/ipa/libipa/colours.h | 21 +++++++++++\n src/ipa/libipa/meson.build | 2 +\n 3 files changed, 100 insertions(+)\n create mode 100644 src/ipa/libipa/colours.cpp\n create mode 100644 src/ipa/libipa/colours.h","diff":"diff --git a/src/ipa/libipa/colours.cpp b/src/ipa/libipa/colours.cpp\nnew file mode 100644\nindex 00000000..9fcb53b0\n--- /dev/null\n+++ b/src/ipa/libipa/colours.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 colour helpers\n+ */\n+\n+#include \"colours.h\"\n+\n+#include \n+#include \n+\n+namespace libcamera {\n+\n+namespace ipa {\n+\n+/**\n+ * \\file colours.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(double r, double g, double 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/colours.h b/src/ipa/libipa/colours.h\nnew file mode 100644\nindex 00000000..b42ed0ac\n--- /dev/null\n+++ b/src/ipa/libipa/colours.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 colour helpers\n+ */\n+\n+#pragma once\n+\n+#include \n+\n+namespace libcamera {\n+\n+namespace ipa {\n+\n+double rec601LuminanceFromRGB(double r, double g, double 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..788d037a 100644\n--- a/src/ipa/libipa/meson.build\n+++ b/src/ipa/libipa/meson.build\n@@ -4,6 +4,7 @@ libipa_headers = files([\n 'agc_mean_luminance.h',\n 'algorithm.h',\n 'camera_sensor_helper.h',\n+ 'colours.h',\n 'exposure_mode_helper.h',\n 'fc_queue.h',\n 'histogram.h',\n@@ -19,6 +20,7 @@ libipa_sources = files([\n 'agc_mean_luminance.cpp',\n 'algorithm.cpp',\n 'camera_sensor_helper.cpp',\n+ 'colours.cpp',\n 'exposure_mode_helper.cpp',\n 'fc_queue.cpp',\n 'histogram.cpp',\n","prefixes":["v3","1/6"]}