[v2,10/10] test: ipa: libipa: Add CCM row-sum validation test

26667 diff mbox series

Verify that each row of a colour correction matrix sums to 1.0
(luminance preservation property). Tests cover:
- identity and known-bad inline matrices
- a real OV01A10 D65 calibrated CCM
- parsing a multi-entry CCM YAML table via Interpolator<Matrix>
- detection of a bad entry in YAML

Tolerance is 5e-4 to accommodate 4-decimal-place rounding in tuning files.

Signed-off-by: d3vv3 <devve.3@gmail.com>
---
 test/ipa/libipa/ccm.cpp     | 158 ++++++++++++++++++++++++++++++++++++
 test/ipa/libipa/meson.build |   1 +
 2 files changed, 159 insertions(+)
 create mode 100644 test/ipa/libipa/ccm.cpp

d3vv3 <devve.3@gmail.com> writes:

> Verify that each row of a colour correction matrix sums to 1.0
> (luminance preservation property). Tests cover:
> - identity and known-bad inline matrices
> - a real OV01A10 D65 calibrated CCM
> - parsing a multi-entry CCM YAML table via Interpolator<Matrix>
> - detection of a bad entry in YAML

I'm not sure I get the purpose of the test -- it looks like it tests
mostly stuff defined in the test itself.  What libcamera functionality
related to row sums is it supposed to test?

> Tolerance is 5e-4 to accommodate 4-decimal-place rounding in tuning files.
>
> Signed-off-by: d3vv3 <devve.3@gmail.com>
> ---
>  test/ipa/libipa/ccm.cpp     | 158 ++++++++++++++++++++++++++++++++++++
>  test/ipa/libipa/meson.build |   1 +
>  2 files changed, 159 insertions(+)
>  create mode 100644 test/ipa/libipa/ccm.cpp
>
> diff --git a/test/ipa/libipa/ccm.cpp b/test/ipa/libipa/ccm.cpp
> new file mode 100644
> index 00000000..efc0035a
> --- /dev/null
> +++ b/test/ipa/libipa/ccm.cpp
> @@ -0,0 +1,158 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +/*
> + * Copyright (C) 2024-2026, Red Hat Inc.
> + *
> + * CCM matrix row-sum validation tests
> + *
> + * Each row of a colour correction matrix must sum to 1.0 (luminance
> + * preservation).  This test verifies that property for inline matrix data
> + * and for matrices parsed from a YAML CCM table.
> + */
> +
> +#include "../../../src/ipa/libipa/interpolator.h"
> +
> +#include <cmath>
> +#include <iostream>
> +#include <string>
> +#include <unistd.h>
> +
> +#include "libcamera/base/file.h"
> +#include "libcamera/internal/matrix.h"
> +#include "libcamera/internal/yaml_parser.h"
> +
> +#include "test.h"
> +
> +using namespace std;
> +using namespace libcamera;
> +using namespace ipa;
> +
> +/* Tolerance for floating-point row-sum comparison.
> + * CCM values in tuning files are typically given to 4 decimal places,
> + * which can introduce up to ~0.5e-3 rounding error per row. */
> +static constexpr float kRowSumTolerance = 5e-4f;
> +
> +#define ASSERT_TRUE(cond)                             \
> +	do {                                          \
> +		if (!(cond)) {                        \
> +			cerr << "FAIL: " #cond "\n";  \
> +			return TestFail;              \
> +		}                                     \
> +	} while (0)
> +
> +static bool allRowsSumToOne(const Matrix<float, 3, 3> &m)
> +{
> +	for (unsigned int row = 0; row < 3; row++) {
> +		float sum = 0.0f;
> +		for (unsigned int col = 0; col < 3; col++)
> +			sum += m[row][col];
> +		if (std::abs(sum - 1.0f) > kRowSumTolerance)
> +			return false;
> +	}
> +	return true;
> +}
> +
> +class CcmRowSumTest : public Test
> +{
> +protected:
> +	bool writeTempYaml(const std::string &content, std::string &filename)
> +	{
> +		filename = "/tmp/libcamera.ccm.test.XXXXXX";
> +		int fd = mkstemp(&filename.front());
> +		if (fd == -1)
> +			return false;
> +		ssize_t ret = write(fd, content.c_str(), content.size());
> +		close(fd);
> +		return ret == static_cast<ssize_t>(content.size());
> +	}
> +
> +	std::unique_ptr<ValueNode> parseYaml(const std::string &content)
> +	{
> +		std::string filename;
> +		if (!writeTempYaml(content, filename))
> +			return nullptr;
> +
> +		File file{ filename };
> +		if (!file.open(File::OpenModeFlag::ReadOnly))
> +			return nullptr;
> +
> +		auto root = YamlParser::parse(file);
> +		unlink(filename.c_str());
> +		return root;
> +	}
> +
> +	int run()
> +	{
> +		/* --- 1. Known-good identity matrix --- */
> +		Matrix<float, 3, 3> identity{ { 1, 0, 0,
> +						0, 1, 0,
> +						0, 0, 1 } };
> +		ASSERT_TRUE(allRowsSumToOne(identity));
> +
> +		/* --- 2. Known-bad matrix (rows do not sum to 1) --- */
> +		Matrix<float, 3, 3> bad{ { 2, 0, 0,
> +					   0, 1, 0,
> +					   0, 0, 1 } };
> +		ASSERT_TRUE(!allRowsSumToOne(bad));
> +
> +		/* --- 3. Typical calibrated CCM (D65, OV01A10) --- */
> +		Matrix<float, 3, 3> d65{ {  1.8163f, -0.7062f, -0.1100f,
> +					   -0.1640f,  1.5736f, -0.4096f,
> +					   -0.0084f, -0.8294f,  1.8378f } };
> +		ASSERT_TRUE(allRowsSumToOne(d65));
> +
> +		/* --- 4. Parse a valid CCM table from YAML and validate --- */
> +		const std::string validYaml =
> +			"- ct: 2856\n"
> +			"  ccm: [  1.1248,  0.2210, -0.3458,\n"
> +			"         -0.4616,  1.7736, -0.3120,\n"
> +			"         -0.4342, -0.9348,  2.3690 ]\n"
> +			"- ct: 6500\n"
> +			"  ccm: [  1.8163, -0.7062, -0.1100,\n"
> +			"         -0.1640,  1.5736, -0.4096,\n"
> +			"         -0.0084, -0.8294,  1.8378 ]\n"
> +			"- ct: 7500\n"
> +			"  ccm: [  1.8953, -0.7980, -0.0973,\n"
> +			"         -0.1539,  1.6001, -0.4462,\n"
> +			"         -0.0101, -0.7800,  1.7902 ]\n";
> +
> +		auto root = parseYaml(validYaml);
> +		ASSERT_TRUE(root);
> +
> +		Interpolator<Matrix<float, 3, 3>> interp;
> +		ASSERT_TRUE(interp.readYaml(*root, "ct", "ccm") == 0);
> +		ASSERT_TRUE(interp.data().size() == 3);
> +
> +		for (const auto &[ct, m] : interp.data()) {
> +			if (!allRowsSumToOne(m)) {
> +				cerr << "CCM at ct=" << ct
> +				     << " has a row that does not sum to 1.0\n";
> +				return TestFail;
> +			}
> +		}
> +
> +		/* --- 5. Detect a bad entry in YAML --- */
> +		const std::string badYaml =
> +			"- ct: 5000\n"
> +			"  ccm: [  2.0000, -0.7062, -0.1100,\n"
> +			"         -0.1640,  1.5736, -0.4096,\n"
> +			"         -0.0084, -0.8294,  1.8378 ]\n";
> +
> +		auto badRoot = parseYaml(badYaml);
> +		ASSERT_TRUE(badRoot);
> +
> +		Interpolator<Matrix<float, 3, 3>> badInterp;
> +		ASSERT_TRUE(badInterp.readYaml(*badRoot, "ct", "ccm") == 0);
> +
> +		for (const auto &[ct, m] : badInterp.data()) {
> +			if (allRowsSumToOne(m)) {
> +				cerr << "Expected bad CCM at ct=" << ct
> +				     << " to fail row-sum check, but it passed\n";
> +				return TestFail;
> +			}
> +		}
> +
> +		return TestPass;
> +	}
> +};
> +
> +TEST_REGISTER(CcmRowSumTest)
> diff --git a/test/ipa/libipa/meson.build b/test/ipa/libipa/meson.build
> index c3e25587..8c36800c 100644
> --- a/test/ipa/libipa/meson.build
> +++ b/test/ipa/libipa/meson.build
> @@ -1,6 +1,7 @@
>  # SPDX-License-Identifier: CC0-1.0
>  
>  libipa_test = [
> +    {'name': 'ccm', 'sources': ['ccm.cpp']},
>      {'name': 'fixedpoint', 'sources': ['fixedpoint.cpp']},
>      {'name': 'histogram', 'sources': ['histogram.cpp']},
>      {'name': 'interpolator', 'sources': ['interpolator.cpp']},