[{"id":38858,"web_url":"https://patchwork.libcamera.org/comment/38858/","msgid":"<855x4ut46t.fsf@mzamazal-thinkpadp1gen7.tpbc.csb>","date":"2026-05-11T14:24:10","subject":"Re: [PATCH v2 10/10] test: ipa: libipa: Add CCM row-sum validation\n\ttest","submitter":{"id":177,"url":"https://patchwork.libcamera.org/api/people/177/","name":"Milan Zamazal","email":"mzamazal@redhat.com"},"content":"d3vv3 writes:\n\n> Verify that each row of a colour correction matrix sums to 1.0\n> (luminance preservation property). Tests cover:\n> - identity and known-bad inline matrices\n> - a real OV01A10 D65 calibrated CCM\n> - parsing a multi-entry CCM YAML table via Interpolator\n> - detection of a bad entry in YAML\n\nI'm not sure I get the purpose of the test -- it looks like it tests\nmostly stuff defined in the test itself. What libcamera functionality\nrelated to row sums is it supposed to test?\n\n> Tolerance is 5e-4 to accommodate 4-decimal-place rounding in tuning files.\n>\n> Signed-off-by: d3vv3 \n> ---\n> test/ipa/libipa/ccm.cpp | 158 ++++++++++++++++++++++++++++++++++++\n> test/ipa/libipa/meson.build | 1 +\n> 2 files changed, 159 insertions(+)\n> create mode 100644 test/ipa/libipa/ccm.cpp\n>\n> diff --git a/test/ipa/libipa/ccm.cpp b/test/ipa/libipa/ccm.cpp\n> new file mode 100644\n> index 00000000..efc0035a\n> --- /dev/null\n> +++ b/test/ipa/libipa/ccm.cpp\n> @@ -0,0 +1,158 @@\n> +/* SPDX-License-Identifier: GPL-2.0-or-later */\n> +/*\n> + * Copyright (C) 2024-2026, Red Hat Inc.\n> + *\n> + * CCM matrix row-sum validation tests\n> + *\n> + * Each row of a colour correction matrix must sum to 1.0 (luminance\n> + * preservation). This test verifies that property for inline matrix data\n> + * and for matrices parsed from a YAML CCM table.\n> + */\n> +\n> +#include \"../../../src/ipa/libipa/interpolator.h\"\n> +\n> +#include \n> +#include \n> +#include \n> +#include \n> +\n> +#include \"libcamera/base/file.h\"\n> +#include \"libcamera/internal/matrix.h\"\n> +#include \"libcamera/internal/yaml_parser.h\"\n> +\n> +#include \"test.h\"\n> +\n> +using namespace std;\n> +using namespace libcamera;\n> +using namespace ipa;\n> +\n> +/* Tolerance for floating-point row-sum comparison.\n> + * CCM values in tuning files are typically given to 4 decimal places,\n> + * which can introduce up to ~0.5e-3 rounding error per row. */\n> +static constexpr float kRowSumTolerance = 5e-4f;\n> +\n> +#define ASSERT_TRUE(cond) \\\n> +\tdo { \\\n> +\t\tif (!(cond)) { \\\n> +\t\t\tcerr << \"FAIL: \" #cond \"\\n\"; \\\n> +\t\t\treturn TestFail; \\\n> +\t\t} \\\n> +\t} while (0)\n> +\n> +static bool allRowsSumToOne(const Matrix &m)\n> +{\n> +\tfor (unsigned int row = 0; row < 3; row++) {\n> +\t\tfloat sum = 0.0f;\n> +\t\tfor (unsigned int col = 0; col < 3; col++)\n> +\t\t\tsum += m[row][col];\n> +\t\tif (std::abs(sum - 1.0f) > kRowSumTolerance)\n> +\t\t\treturn false;\n> +\t}\n> +\treturn true;\n> +}\n> +\n> +class CcmRowSumTest : public Test\n> +{\n> +protected:\n> +\tbool writeTempYaml(const std::string &content, std::string &filename)\n> +\t{\n> +\t\tfilename = \"/tmp/libcamera.ccm.test.XXXXXX\";\n> +\t\tint fd = mkstemp(&filename.front());\n> +\t\tif (fd == -1)\n> +\t\t\treturn false;\n> +\t\tssize_t ret = write(fd, content.c_str(), content.size());\n> +\t\tclose(fd);\n> +\t\treturn ret == static_cast(content.size());\n> +\t}\n> +\n> +\tstd::unique_ptr parseYaml(const std::string &content)\n> +\t{\n> +\t\tstd::string filename;\n> +\t\tif (!writeTempYaml(content, filename))\n> +\t\t\treturn nullptr;\n> +\n> +\t\tFile file{ filename };\n> +\t\tif (!file.open(File::OpenModeFlag::ReadOnly))\n> +\t\t\treturn nullptr;\n> +\n> +\t\tauto root = YamlParser::parse(file);\n> +\t\tunlink(filename.c_str());\n> +\t\treturn root;\n> +\t}\n> +\n> +\tint run()\n> +\t{\n> +\t\t/* --- 1. Known-good identity matrix --- */\n> +\t\tMatrix identity{ { 1, 0, 0,\n> +\t\t\t\t\t\t0, 1, 0,\n> +\t\t\t\t\t\t0, 0, 1 } };\n> +\t\tASSERT_TRUE(allRowsSumToOne(identity));\n> +\n> +\t\t/* --- 2. Known-bad matrix (rows do not sum to 1) --- */\n> +\t\tMatrix bad{ { 2, 0, 0,\n> +\t\t\t\t\t 0, 1, 0,\n> +\t\t\t\t\t 0, 0, 1 } };\n> +\t\tASSERT_TRUE(!allRowsSumToOne(bad));\n> +\n> +\t\t/* --- 3. Typical calibrated CCM (D65, OV01A10) --- */\n> +\t\tMatrix d65{ { 1.8163f, -0.7062f, -0.1100f,\n> +\t\t\t\t\t -0.1640f, 1.5736f, -0.4096f,\n> +\t\t\t\t\t -0.0084f, -0.8294f, 1.8378f } };\n> +\t\tASSERT_TRUE(allRowsSumToOne(d65));\n> +\n> +\t\t/* --- 4. Parse a valid CCM table from YAML and validate --- */\n> +\t\tconst std::string validYaml =\n> +\t\t\t\"- ct: 2856\\n\"\n> +\t\t\t\" ccm: [ 1.1248, 0.2210, -0.3458,\\n\"\n> +\t\t\t\" -0.4616, 1.7736, -0.3120,\\n\"\n> +\t\t\t\" -0.4342, -0.9348, 2.3690 ]\\n\"\n> +\t\t\t\"- ct: 6500\\n\"\n> +\t\t\t\" ccm: [ 1.8163, -0.7062, -0.1100,\\n\"\n> +\t\t\t\" -0.1640, 1.5736, -0.4096,\\n\"\n> +\t\t\t\" -0.0084, -0.8294, 1.8378 ]\\n\"\n> +\t\t\t\"- ct: 7500\\n\"\n> +\t\t\t\" ccm: [ 1.8953, -0.7980, -0.0973,\\n\"\n> +\t\t\t\" -0.1539, 1.6001, -0.4462,\\n\"\n> +\t\t\t\" -0.0101, -0.7800, 1.7902 ]\\n\";\n> +\n> +\t\tauto root = parseYaml(validYaml);\n> +\t\tASSERT_TRUE(root);\n> +\n> +\t\tInterpolator> interp;\n> +\t\tASSERT_TRUE(interp.readYaml(*root, \"ct\", \"ccm\") == 0);\n> +\t\tASSERT_TRUE(interp.data().size() == 3);\n> +\n> +\t\tfor (const auto &[ct, m] : interp.data()) {\n> +\t\t\tif (!allRowsSumToOne(m)) {\n> +\t\t\t\tcerr << \"CCM at ct=\" << ct\n> +\t\t\t\t << \" has a row that does not sum to 1.0\\n\";\n> +\t\t\t\treturn TestFail;\n> +\t\t\t}\n> +\t\t}\n> +\n> +\t\t/* --- 5. Detect a bad entry in YAML --- */\n> +\t\tconst std::string badYaml =\n> +\t\t\t\"- ct: 5000\\n\"\n> +\t\t\t\" ccm: [ 2.0000, -0.7062, -0.1100,\\n\"\n> +\t\t\t\" -0.1640, 1.5736, -0.4096,\\n\"\n> +\t\t\t\" -0.0084, -0.8294, 1.8378 ]\\n\";\n> +\n> +\t\tauto badRoot = parseYaml(badYaml);\n> +\t\tASSERT_TRUE(badRoot);\n> +\n> +\t\tInterpolator> badInterp;\n> +\t\tASSERT_TRUE(badInterp.readYaml(*badRoot, \"ct\", \"ccm\") == 0);\n> +\n> +\t\tfor (const auto &[ct, m] : badInterp.data()) {\n> +\t\t\tif (allRowsSumToOne(m)) {\n> +\t\t\t\tcerr << \"Expected bad CCM at ct=\" << ct\n> +\t\t\t\t << \" to fail row-sum check, but it passed\\n\";\n> +\t\t\t\treturn TestFail;\n> +\t\t\t}\n> +\t\t}\n> +\n> +\t\treturn TestPass;\n> +\t}\n> +};\n> +\n> +TEST_REGISTER(CcmRowSumTest)\n> diff --git a/test/ipa/libipa/meson.build b/test/ipa/libipa/meson.build\n> index c3e25587..8c36800c 100644\n> --- a/test/ipa/libipa/meson.build\n> +++ b/test/ipa/libipa/meson.build\n> @@ -1,6 +1,7 @@\n> # SPDX-License-Identifier: CC0-1.0\n> \n> libipa_test = [\n> + {'name': 'ccm', 'sources': ['ccm.cpp']},\n> {'name': 'fixedpoint', 'sources': ['fixedpoint.cpp']},\n> {'name': 'histogram', 'sources': ['histogram.cpp']},\n> {'name': 'interpolator', 'sources': ['interpolator.cpp']},","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 5CB16BDCBD\n\tfor ;\n\tMon, 11 May 2026 14:24:24 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 4ABAE6301E;\n\tMon, 11 May 2026 16:24:23 +0200 (CEST)","from us-smtp-delivery-124.mimecast.com\n\t(us-smtp-delivery-124.mimecast.com [170.10.129.124])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 0F6AF62DC4\n\tfor ;\n\tMon, 11 May 2026 16:24:21 +0200 (CEST)","from mail-wm1-f69.google.com (mail-wm1-f69.google.com\n\t[209.85.128.69]) by relay.mimecast.com with ESMTP with STARTTLS\n\t(version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id\n\tus-mta-655-YUHDbcM4O6CMOW3UWOnqQg-1; Mon, 11 May 2026 10:24:15 -0400","by mail-wm1-f69.google.com with SMTP id\n\t5b1f17b1804b1-488c0120047so26438595e9.0\n\tfor ;\n\tMon, 11 May 2026 07:24:13 -0700 (PDT)","from mzamazal-thinkpadp1gen7.tpbc.csb\n\t(ip-77-48-47-4.net.vodafone.cz. 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