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

libcamera v0.7.1 Supporting cameras in Linux since 2019

Loading...
Searching...
No Matches
lsc_polynomial.h
Go to the documentation of this file.
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/geometry.h>
18
19#include "libcamera/internal/value_node.h"
20
21namespace libcamera {
22
23 LOG_DECLARE_CATEGORY(LscPolynomial)
24
25namespace ipa {
26
27 class LscPolynomial
28{
29public:
30 LscPolynomial(double cx = 0.0, double cy = 0.0, double k0 = 0.0,
31 double k1 = 0.0, double k2 = 0.0, double k3 = 0.0,
32 double k4 = 0.0)
33 : cx_(cx), cy_(cy), cnx_(0), cny_(0),
34 coefficients_({ k0, k1, k2, k3, k4 })
35 {
36 }
37
38 double sampleAtNormalizedPixelPos(double x, double y) const
39 {
40 double dx = x - cnx_;
41 double dy = y - cny_;
42 double r = sqrt(dx * dx + dy * dy);
43 double res = 1.0;
44 for (unsigned int i = 0; i < coefficients_.size(); i++) {
45 res += coefficients_[i] * std::pow(r, (i + 1) * 2);
46 }
47 return res;
48 }
49
50 double getM() const
51 {
52 double cpx = imageSize_.width * cx_;
53 double cpy = imageSize_.height * cy_;
54 double mx = std::max(cpx, std::fabs(imageSize_.width - cpx));
55 double my = std::max(cpy, std::fabs(imageSize_.height - cpy));
56
57 return sqrt(mx * mx + my * my);
58 }
59
60 void setReferenceImageSize(const Size &size)
61 {
62 assert(!size.isNull());
63 imageSize_ = size;
64
65 /* Calculate normalized centers */
66 double m = getM();
67 cnx_ = (size.width * cx_) / m;
68 cny_ = (size.height * cy_) / m;
69 }
70
71private:
72 double cx_;
73 double cy_;
74 double cnx_;
75 double cny_;
76 std::array<double, 5> coefficients_;
77
78 Size imageSize_;
79};
80
81} /* namespace ipa */
82
83#ifndef __DOXYGEN__
84
85template<>
86struct ValueNode::Accessor<ipa::LscPolynomial> {
87 std::optional<ipa::LscPolynomial> get(const ValueNode &obj) const
88 {
89 std::optional<double> cx = obj["cx"].get<double>();
90 std::optional<double> cy = obj["cy"].get<double>();
91 std::optional<double> k0 = obj["k0"].get<double>();
92 std::optional<double> k1 = obj["k1"].get<double>();
93 std::optional<double> k2 = obj["k2"].get<double>();
94 std::optional<double> k3 = obj["k3"].get<double>();
95 std::optional<double> k4 = obj["k4"].get<double>();
96
97 if (!(cx && cy && k0 && k1 && k2 && k3 && k4))
98 LOG(LscPolynomial, Error)
99 << "Polynomial is missing a parameter";
100
101 return ipa::LscPolynomial(*cx, *cy, *k0, *k1, *k2, *k3, *k4);
102 }
103};
104
105#endif
106
107} /* 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::ValueNode::get
std::optional< T > get() const
Parse the ValueNode as a T value.
Definition value_node.h:211
libcamera::ipa::LscPolynomial::setReferenceImageSize
void setReferenceImageSize(const Size &size)
Set the reference image size.
Definition lsc_polynomial.h:60
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:30
libcamera::ipa::LscPolynomial::getM
double getM() const
Get the value m as described in the dng specification.
Definition lsc_polynomial.h:50
libcamera::ipa::LscPolynomial::sampleAtNormalizedPixelPos
double sampleAtNormalizedPixelPos(double x, double y) const
Sample the polynomial at the given normalized pixel position.
Definition lsc_polynomial.h:38
geometry.h
Data structures related to geometric objects.
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
libcamera::ipa
The IPA (Image Processing Algorithm) namespace.
Definition af.cpp:58
libcamera
Top-level libcamera namespace.
Definition backtrace.h:17
value_node.h
Data structure to manage tree of values.