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

libcamera v0.5.0 Supporting cameras in Linux since 2019 |

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lsc_polynomial.h
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1/* SPDX-License-Identifier: LGPL-2.1-or-later */
2/*
3 * Copyright (C) 2024, Ideas On Board
4 *
5 * Helper for radial polynomial used in lens shading correction.
6 */
7#pragma once
8
9#include <algorithm>
10#include <array>
11#include <assert.h>
12#include <cmath>
13
14#include <libcamera/base/log.h>
15#include <libcamera/base/span.h>
16
17#include "libcamera/internal/yaml_parser.h"
18
19namespace libcamera {
20
21 LOG_DECLARE_CATEGORY(LscPolynomial)
22
23namespace ipa {
24
25 class LscPolynomial
26{
27public:
28 LscPolynomial(double cx = 0.0, double cy = 0.0, double k0 = 0.0,
29 double k1 = 0.0, double k2 = 0.0, double k3 = 0.0,
30 double k4 = 0.0)
31 : cx_(cx), cy_(cy), cnx_(0), cny_(0),
32 coefficients_({ k0, k1, k2, k3, k4 })
33 {
34 }
35
36 double sampleAtNormalizedPixelPos(double x, double y) const
37 {
38 double dx = x - cnx_;
39 double dy = y - cny_;
40 double r = sqrt(dx * dx + dy * dy);
41 double res = 1.0;
42 for (unsigned int i = 0; i < coefficients_.size(); i++) {
43 res += coefficients_[i] * std::pow(r, (i + 1) * 2);
44 }
45 return res;
46 }
47
48 double getM() const
49 {
50 double cpx = imageSize_.width * cx_;
51 double cpy = imageSize_.height * cy_;
52 double mx = std::max(cpx, std::fabs(imageSize_.width - cpx));
53 double my = std::max(cpy, std::fabs(imageSize_.height - cpy));
54
55 return sqrt(mx * mx + my * my);
56 }
57
58 void setReferenceImageSize(const Size &size)
59 {
60 assert(!size.isNull());
61 imageSize_ = size;
62
63 /* Calculate normalized centers */
64 double m = getM();
65 cnx_ = (size.width * cx_) / m;
66 cny_ = (size.height * cy_) / m;
67 }
68
69private:
70 double cx_;
71 double cy_;
72 double cnx_;
73 double cny_;
74 std::array<double, 5> coefficients_;
75
76 Size imageSize_;
77};
78
79} /* namespace ipa */
80
81#ifndef __DOXYGEN__
82
83template<>
84struct YamlObject::Getter<ipa::LscPolynomial> {
85 std::optional<ipa::LscPolynomial> get(const YamlObject &obj) const
86 {
87 std::optional<double> cx = obj["cx"].get<double>();
88 std::optional<double> cy = obj["cy"].get<double>();
89 std::optional<double> k0 = obj["k0"].get<double>();
90 std::optional<double> k1 = obj["k1"].get<double>();
91 std::optional<double> k2 = obj["k2"].get<double>();
92 std::optional<double> k3 = obj["k3"].get<double>();
93 std::optional<double> k4 = obj["k4"].get<double>();
94
95 if (!(cx && cy && k0 && k1 && k2 && k3 && k4))
96 LOG(LscPolynomial, Error)
97 << "Polynomial is missing a parameter";
98
99 return ipa::LscPolynomial(*cx, *cy, *k0, *k1, *k2, *k3, *k4);
100 }
101};
102
103#endif
104
105} /* namespace libcamera */
libcamera::Size
Describe a two-dimensional size.
Definition geometry.h:51
libcamera::Size::width
unsigned int width
The Size width.
Definition geometry.h:63
libcamera::Size::height
unsigned int height
The Size height.
Definition geometry.h:64
libcamera::Size::isNull
bool isNull() const
Check if the size is null.
Definition geometry.h:66
libcamera::YamlObject::get
std::optional< T > get() const
Parse the YamlObject as a T value.
Definition yaml_parser.h:175
libcamera::ipa::LscPolynomial::setReferenceImageSize
void setReferenceImageSize(const Size &size)
Set the reference image size.
Definition lsc_polynomial.h:58
libcamera::ipa::LscPolynomial::LscPolynomial
LscPolynomial(double cx=0.0, double cy=0.0, double k0=0.0, double k1=0.0, double k2=0.0, double k3=0.0, double k4=0.0)
Construct a polynomial using the given coefficients.
Definition lsc_polynomial.h:28
libcamera::ipa::LscPolynomial::getM
double getM() const
Get the value m as described in the dng specification.
Definition lsc_polynomial.h:48
libcamera::ipa::LscPolynomial::sampleAtNormalizedPixelPos
double sampleAtNormalizedPixelPos(double x, double y) const
Sample the polynomial at the given normalized pixel position.
Definition lsc_polynomial.h:36
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:123
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.