[PATCH v3 2/3] ipa: libipa: Add MatrixInterpolator class
Paul Elder
paul.elder at ideasonboard.com
Fri May 17 05:50:50 CEST 2024
On Wed, May 15, 2024 at 11:20:56AM +0200, Stefan Klug wrote:
> On Tue, May 07, 2024 at 03:10:15PM +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>
> >
> > ---
> > Changes in v3:
> > - add a constructor that takes a map of unsigned int -> matrix
> > - s/unit/identity
> > - clear matrices on reset and when reading from yaml
> > - add assert at get()
> >
> > Changes in v2:
> > - initialize to identity matrix
> > - add a function to reset to identity matrix
> > - other minor fixes
> > ---
> > src/ipa/libipa/matrix_interpolator.cpp | 54 ++++++++++++
> > src/ipa/libipa/matrix_interpolator.h | 116 +++++++++++++++++++++++++
> > src/ipa/libipa/meson.build | 2 +
> > 3 files changed, 172 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..fc1837e7
> > --- /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, R, C> 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..2c6263cb
> > --- /dev/null
> > +++ b/src/ipa/libipa/matrix_interpolator.h
> > @@ -0,0 +1,116 @@
> > +/* 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,
> > + std::enable_if_t<std::is_arithmetic_v<T>> * = nullptr>
> > +class MatrixInterpolator
> > +{
> > +public:
> > + MatrixInterpolator()
> > + {
> > + reset();
> > + };
> > +
> > + MatrixInterpolator(const std::map<unsigned int, Matrix<T, R, C>> &matrices)
> > + {
> > + for (const auto &pair : matrices)
> > + matrices_[pair.first] = pair.second;
> > + };
> > +
> > + ~MatrixInterpolator(){};
> > +
> > + void reset()
> > + {
> > + Matrix<T, R, C> identity;
> > + matrices_.clear();
> > + matrices_[0] = identity;
> > + }
> > +
> > + int readYaml(const libcamera::YamlObject &yaml)
> > + {
> > + int ret;
> > +
> > + matrices_.clear();
> > +
> > + if (!yaml.isDictionary()) {
> > + LOG(MatrixInterpolator, Error) << "yaml object must be a dictionary";
> > + return -EINVAL;
> > + }
> > +
>
> I have the feeling that this might not be flexible enough. At the moment
> this expects a yaml representation of
>
> 2000: [ matrix values... ]
> 3000: [ ... ]
>
> We might need to add more infos for a given color temperature. In my
> prototypes I used a list like this:
>
> - ct: 2000
> ccm: [matrix values]
> - ct: 3000
> ccm: [ matrix values ]
Yes, I think that will be necessary, also to match the layout with lsc
so that we can use this for lsc in the future.
>
>
> This adds the flexibility to e.g. add the offset vector.
> My diff is:
> - int readYaml(const libcamera::YamlObject &yaml)
> + int readYaml(const libcamera::YamlObject &yaml, const std::string& key_property, const std::string& value_property)
Ah, good idea. I was trying to figure out how to support different size
matrices in the same map...
> {
> int ret;
>
> matrices_.clear();
>
> - if (!yaml.isDictionary()) {
> - LOG(MatrixInterpolator, Error) << "yaml object must be a dictionary";
> + if (!yaml.isList()) {
> + LOG(MatrixInterpolator, Error) << "yaml object must be a list";
> return -EINVAL;
> }
>
> - for (const auto &[ctStr, value] : yaml.asDict()) {
> - unsigned int ct = std::stoul(ctStr);
> + for (const auto &value : yaml.asList()) {
> + unsigned int ct = std::stoul(value[key_property].get<std::string>(""));
> Matrix<T, R, C> matrix;
> - if ((ret = matrix.readYaml(value)) < 0) {
> + if ((ret = matrix.readYaml(value[value_property])) < 0) {
> LOG(MatrixInterpolator, Error) << "Failed to read matrix";
> return ret;
> }
>
>
>
> I'm not yet sure where we will end up. This largely depends on how the
> tuning file format evolves. What are your thoughts about that?
>
> > + for (const auto &[ctStr, value] : yaml.asDict()) {
> > + unsigned int ct = std::stoul(ctStr);
> > + Matrix<T, R, C> matrix;
> > + if ((ret = matrix.readYaml(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, R, C> get(unsigned int ct)
> > + {
> > + ASSERT(matrices_.size() > 0);
>
> I'm a bit concerned here. This check only runs in debug mode. But in
> case the readYaml gets an invalid object, it leaves the interpolator
> with matrices_.size() == 0 and we would crash here. I think we should at
> least catch that in release mode and maybe return a identity matrix (and
> then there is need to inject the identity in the constructor anymore)
tbh I think it should be fine because it'll be caught in readYaml and we
return -EINVAL. Is that not sufficient?
Thanks,
Paul
>
> > +
> > + 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) / static_cast<double>(ctUpper - ctLower);
> > + return lambda * matrices_[ctUpper] + (1.0 - lambda) * matrices_[ctLower];
> > + }
> > +
> > +private:
> > + std::map<unsigned int, Matrix<T, R, C>> matrices_;
> > +};
> > +
> > +} /* namespace ipa */
> > +
> > +} /* namespace libcamera */
> > diff --git a/src/ipa/libipa/meson.build b/src/ipa/libipa/meson.build
> > index 1e34355f..305acf64 100644
> > --- a/src/ipa/libipa/meson.build
> > +++ b/src/ipa/libipa/meson.build
> > @@ -8,6 +8,7 @@ libipa_headers = files([
> > 'fc_queue.h',
> > 'histogram.h',
> > 'matrix.h',
> > + 'matrix_interpolator.h',
> > 'module.h',
> > 'pwl.h',
> > ])
> > @@ -20,6 +21,7 @@ libipa_sources = files([
> > 'fc_queue.cpp',
> > 'histogram.cpp',
> > 'matrix.cpp',
> > + 'matrix_interpolator.cpp',
> > 'module.cpp',
> > 'pwl.cpp'
> > ])
> > --
> > 2.39.2
> >
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