[PATCH 2/3] ipa: libipa: Add MatrixInterpolator class
Stefan Klug
stefan.klug at ideasonboard.com
Wed Apr 10 23:52:49 CEST 2024
Hi Paul,
thank you for the patch.
On Fri, Apr 05, 2024 at 05:40:49PM +0900, Paul Elder wrote:
> Add a class to encapsulate the functionality of fetching a matrix based
> on an integer key, and interpolating if there is no exact match. This is
> expected to be used by both color correction matrices / crosstalk
> correction as well as lens shading correction.
>
> Signed-off-by: Paul Elder <paul.elder at ideasonboard.com>
> ---
> src/ipa/libipa/matrix_interpolator.cpp | 54 +++++++++++++++
> src/ipa/libipa/matrix_interpolator.h | 94 ++++++++++++++++++++++++++
> src/ipa/libipa/meson.build | 2 +
> 3 files changed, 150 insertions(+)
> create mode 100644 src/ipa/libipa/matrix_interpolator.cpp
> create mode 100644 src/ipa/libipa/matrix_interpolator.h
>
> diff --git a/src/ipa/libipa/matrix_interpolator.cpp b/src/ipa/libipa/matrix_interpolator.cpp
> new file mode 100644
> index 00000000..394633b5
> --- /dev/null
> +++ b/src/ipa/libipa/matrix_interpolator.cpp
> @@ -0,0 +1,54 @@
> +/* SPDX-License-Identifier: BSD-2-Clause */
> +/*
> + * Copyright (C) 2019, Raspberry Pi Ltd
> + * Copyright (C) 2024, Paul Elder <paul.elder at ideasonboard.com>
> + *
> + * matrix_interpolator.cpp - Helper class for interpolating maps of matrices
> + */
> +#include "matrix_interpolator.h"
> +
> +#include <algorithm>
> +#include <string>
> +
> +#include <libcamera/base/log.h>
> +
> +#include "libcamera/internal/yaml_parser.h"
> +
> +#include "matrix.h"
> +
> +/**
> + * \file ccm.h
> + * \brief Helper class for interpolating maps of matrices
> + */
> +
> +namespace libcamera {
> +
> +LOG_DEFINE_CATEGORY(MatrixInterpolator)
> +
> +namespace ipa {
> +
> +/**
> + * \class MatrixInterpolator
> + * \brief Class for storing, retrieving, and interpolating matrices
> + */
> +
> +/**
> + * \fn int MatrixInterpolator<T, R, C>::readYaml(const libcamera::YamlObject &yaml)
> + * \brief Initialize an MatrixInterpolator instance from yaml
> + * \tparam T Type of data stored in the matrices
> + * \tparam R Number of rows of the matrices
> + * \tparam C Number of columns of the matrices
> + * \param[in] yaml The yaml object that contains the map of unsigned integers to matrices
> + * \return Zero on success, negative error code otherwise
> + */
> +
> +/**
> + * \fn Matrix<T> MatrixInterpolator<T, R, C>::get(unsigned int key)
> + * \brief Retrieve a matrix from the list of matrices, interpolating if necessary
> + * \param[in] key The unsigned integer key of the matrix to retrieve
> + * \return The matrix corresponding to the color temperature
> + */
> +
> +} /* namespace ipa */
> +
> +} /* namespace libcamera */
> diff --git a/src/ipa/libipa/matrix_interpolator.h b/src/ipa/libipa/matrix_interpolator.h
> new file mode 100644
> index 00000000..2cd4ff75
> --- /dev/null
> +++ b/src/ipa/libipa/matrix_interpolator.h
> @@ -0,0 +1,94 @@
> +/* SPDX-License-Identifier: BSD-2-Clause */
> +/*
> + * Copyright (C) 2019, Raspberry Pi Ltd
> + * Copyright (C) 2024, Paul Elder <paul.elder at ideasonboard.com>
> + *
> + * matrix_interpolator.h - Helper class for interpolating maps of matrices
> + */
> +
> +#pragma once
> +
> +#include <algorithm>
> +#include <map>
> +#include <string>
> +#include <tuple>
> +
> +#include <libcamera/base/log.h>
> +
> +#include "libcamera/internal/yaml_parser.h"
> +
> +#include "matrix.h"
> +
> +namespace libcamera {
> +
> +LOG_DECLARE_CATEGORY(MatrixInterpolator)
> +
> +namespace ipa {
> +
> +template<typename T, unsigned int R, unsigned int C>
Why does this class use template paramters for rows and cols and the
matrix class does not? I thought about suggesting these tempate params
on the matrix class, but did not due to simplicity reasons. I believe
these should be symetrical. So R and C should also be members here.
> +class MatrixInterpolator
> +{
> +public:
> + MatrixInterpolator(){};
> + ~MatrixInterpolator(){};
> +
> + int readYaml(const libcamera::YamlObject &yaml)
> + {
> + int ret;
> +
> + if (!yaml.isDictionary()) {
> + LOG(MatrixInterpolator, Error) << "yaml object must be a dictionary";
> + return -EINVAL;
> + }
> +
> + for (const auto &[ctStr, value] : yaml.asDict()) {
> + unsigned int ct = std::stoul(ctStr);
> + Matrix<T> matrix;
> + if ((ret = matrix.readYaml(R, C, value)) < 0) {
> + LOG(MatrixInterpolator, Error) << "Failed to read matrix";
> + return ret;
> + }
> +
> + matrices_[ct] = matrix;
> +
> + LOG(MatrixInterpolator, Debug)
> + << "Read matrix for key " << ct << ": "
> + << matrices_[ct].toString();
> + }
> +
> + if (matrices_.size() < 1) {
> + LOG(MatrixInterpolator, Error) << "Need at least one matrix";
> + return -EINVAL;
> + }
> +
> + return 0;
> + }
> +
> + Matrix<T> get(unsigned int ct)
> + {
> + if (matrices_.size() == 1 ||
> + ct <= matrices_.begin()->first)
> + return matrices_.begin()->second;
> +
> + if (ct >= matrices_.rbegin()->first)
> + return matrices_.rbegin()->second;
> +
> + if (matrices_.count(ct))
> + return matrices_[ct];
> +
> + /* The above four guarantee that this will succeed */
> + auto iter = matrices_.upper_bound(ct);
> + unsigned int ctUpper = iter->first;
> + unsigned int ctLower = (--iter)->first;
> +
> + double lambda = (ct - ctLower) / (ctUpper - ctLower);
Both sides of the division are integers, so the division will result in
an integer. I think the denominator must be cast to double or am I
missing something here?
That would be a good case for a small unit test. Simple to write but
saves hours of debugging later.
> + return lambda * matrices_[ctUpper] + (1.0 - lambda) * matrices_[ctLower];
> + }
> +
> +private:
> + std::map<unsigned int, Matrix<T>> matrices_;
> +};
> +
> +} /* namespace ipa */
> +
> +} /* namespace libcamera */
> diff --git a/src/ipa/libipa/meson.build b/src/ipa/libipa/meson.build
> index 5d5ba5e5..128de712 100644
> --- a/src/ipa/libipa/meson.build
> +++ b/src/ipa/libipa/meson.build
> @@ -3,6 +3,7 @@
> libipa_headers = files([
> 'algorithm.h',
> 'camera_sensor_helper.h',
> + 'matrix_interpolator.h',
These should be sorted alphabetically.
> 'exposure_mode_helper.h',
> 'fc_queue.h',
> 'histogram.h',
> @@ -14,6 +15,7 @@ libipa_headers = files([
> libipa_sources = files([
> 'algorithm.cpp',
> 'camera_sensor_helper.cpp',
> + 'matrix_interpolator.cpp',
likewise
> 'exposure_mode_helper.cpp',
> 'fc_queue.cpp',
> 'histogram.cpp',
> --
> 2.39.2
>
Best regards,
Stefan
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