libcamera: src/ipa/libipa/interpolator.h Source File

libcamera v0.7.0 Supporting cameras in Linux since 2019

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interpolator.h
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1/* SPDX-License-Identifier: LGPL-2.1-or-later */
2/*
3 * Copyright (C) 2024, Paul Elder <paul.elder@ideasonboard.com>
4 *
5 * Helper class for interpolating maps of objects
6 */
7
8#pragma once
9
10#include <algorithm>
11#include <cmath>
12#include <map>
13#include <string>
14#include <tuple>
15
16#include <libcamera/base/log.h>
17
18#include "libcamera/internal/yaml_parser.h"
19
20namespace libcamera {
21
22 LOG_DECLARE_CATEGORY(Interpolator)
23
24namespace ipa {
25
26template<typename T>
27 class Interpolator
28{
29public:
30 Interpolator() = default;
31 Interpolator(const std::map<unsigned int, T> &data)
32 : data_(data)
33 {
34 }
35 Interpolator(std::map<unsigned int, T> &&data)
36 : data_(std::move(data))
37 {
38 }
39
40 ~Interpolator() = default;
41
42 int readYaml(const libcamera::YamlObject &yaml,
43 const std::string &key_name,
44 const std::string &value_name)
45 {
46 data_.clear();
47 lastInterpolatedKey_.reset();
48
49 if (!yaml.isList()) {
50 LOG(Interpolator, Error) << "yaml object must be a list";
51 return -EINVAL;
52 }
53
54 for (const auto &value : yaml.asList()) {
55 unsigned int ct = std::stoul(value[key_name].get<std::string>(""));
56 std::optional<T> data =
57 value[value_name].get<T>();
58 if (!data) {
59 return -EINVAL;
60 }
61
62 data_[ct] = *data;
63 }
64
65 if (data_.size() < 1) {
66 LOG(Interpolator, Error) << "Need at least one element";
67 return -EINVAL;
68 }
69
70 return 0;
71 }
72
73 void setData(std::map<unsigned int, T> &&data)
74 {
75 data_ = std::move(data);
76 lastInterpolatedKey_.reset();
77 }
78
79 const std::map<unsigned int, T> &data() const
80 {
81 return data_;
82 }
83
84 const T &getInterpolated(unsigned int key)
85 {
86 ASSERT(data_.size() > 0);
87
88 if (lastInterpolatedKey_.has_value() &&
89 *lastInterpolatedKey_ == key)
90 return lastInterpolatedValue_;
91
92 auto it = data_.lower_bound(key);
93
94 if (it == data_.begin())
95 return it->second;
96
97 if (it == data_.end())
98 return std::prev(it)->second;
99
100 if (it->first == key)
101 return it->second;
102
103 auto it2 = std::prev(it);
104 double lambda = (key - it2->first) / static_cast<double>(it->first - it2->first);
105 interpolate(it2->second, it->second, lastInterpolatedValue_, lambda);
106 lastInterpolatedKey_ = key;
107
108 return lastInterpolatedValue_;
109 }
110
111 void interpolate(const T &a, const T &b, T &dest, double lambda)
112 {
113 dest = a * (1.0 - lambda) + b * lambda;
114 }
115
116private:
117 std::map<unsigned int, T> data_;
118 T lastInterpolatedValue_;
119 std::optional<unsigned int> lastInterpolatedKey_;
120};
121
122} /* namespace ipa */
123
124} /* namespace libcamera */
libcamera::YamlObject
A class representing the tree structure of the YAML content.
Definition yaml_parser.h:28
libcamera::YamlObject::asList
ListAdapter asList() const
Wrap a list YamlObject in an adapter that exposes iterators.
Definition yaml_parser.h:206
libcamera::YamlObject::isList
bool isList() const
Return whether the YamlObject is a list.
Definition yaml_parser.h:155
libcamera::ipa::Interpolator
Class for storing, retrieving, and interpolating objects.
Definition interpolator.h:28
libcamera::ipa::Interpolator::getInterpolated
const T & getInterpolated(unsigned int key)
Retrieve an interpolated value for the given key.
Definition interpolator.h:84
libcamera::ipa::Interpolator::Interpolator
Interpolator(const std::map< unsigned int, T > &data)
Construct an interpolator from a map of objects.
Definition interpolator.h:31
libcamera::ipa::Interpolator::setData
void setData(std::map< unsigned int, T > &&data)
Set the internal map.
Definition interpolator.h:73
libcamera::ipa::Interpolator::Interpolator
Interpolator()=default
Construct an empty interpolator.
libcamera::ipa::Interpolator::data
const std::map< unsigned int, T > & data() const
Access the internal map.
Definition interpolator.h:79
libcamera::ipa::Interpolator::Interpolator
Interpolator(std::map< unsigned int, T > &&data)
Construct an interpolator from a map of objects.
Definition interpolator.h:35
libcamera::ipa::Interpolator::readYaml
int readYaml(const libcamera::YamlObject &yaml, const std::string &key_name, const std::string &value_name)
Initialize an Interpolator instance from yaml.
Definition interpolator.h:42
libcamera::ipa::Interpolator::interpolate
void interpolate(const T &a, const T &b, T &dest, double lambda)
Interpolate between two instances of T.
Definition interpolator.h:111
log.h
Logging infrastructure.
LOG_DECLARE_CATEGORY
#define LOG_DECLARE_CATEGORY(name)
Declare a category of log messages.
Definition log.h:51
LOG
#define LOG(category, severity)
Log a message.
Definition log.h:129
ASSERT
#define ASSERT(condition)
Abort program execution if assertion fails.
Definition log.h:133
libcamera::ipa
The IPA (Image Processing Algorithm) namespace.
Definition af.cpp:58
libcamera
Top-level libcamera namespace.
Definition backtrace.h:17
yaml_parser.h
A YAML parser helper.