@@ -10,6 +10,7 @@ libipa_headers = files([
'interpolator.h',
'matrix.h',
'module.h',
+ 'polynomial.h',
'pwl.h',
'vector.h',
])
@@ -24,6 +25,7 @@ libipa_sources = files([
'interpolator.cpp',
'matrix.cpp',
'module.cpp',
+ 'polynomial.cpp',
'pwl.cpp',
'vector.cpp',
])
new file mode 100644
@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2024, Ideas On Board
+ *
+ * Polynomal class to represent lens shading correction
+ */
+
+#include "polynomial.h"
+
+#include <libcamera/base/log.h>
+
+/**
+ * \file polynomial.h
+ * \brief Polynomial class
+ */
+
+namespace libcamera {
+
+LOG_DEFINE_CATEGORY(Polynomial)
+
+namespace ipa {
+}
+} // namespace libcamera
new file mode 100644
@@ -0,0 +1,107 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2024, Ideas On Board
+ *
+ * Vector and related operations
+ */
+#pragma once
+
+#include <algorithm>
+#include <array>
+#include <assert.h>
+#include <cmath>
+
+#include <libcamera/base/log.h>
+#include <libcamera/base/span.h>
+
+#include "libcamera/internal/yaml_parser.h"
+
+namespace libcamera {
+
+LOG_DECLARE_CATEGORY(Polynomial)
+
+namespace ipa {
+
+constexpr int kNumCoefficients = 5;
+class Polynomial
+{
+public:
+ /**
+ * Note: cx and cy are relative to the image size
+ */
+ Polynomial(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)
+ : cx_(cx), cy_(cy),
+ coefficients_({ k0, k1, k2, k3, k4 })
+ {
+ }
+
+ double sampleAtNormalizedPixelPos(double x, double y) const
+ {
+ double dx = x - cnx_;
+ double dy = y - cny_;
+ double r = sqrt(dx * dx + dy * dy);
+ double res = 1.0;
+ for (int i = 0; i < kNumCoefficients; i++) {
+ res += coefficients_[i] * std::pow(r, (i + 1) * 2);
+ }
+ return res;
+ }
+
+ /**
+ * Returns m according to dng spec. 𝑚 represents the Euclidean distance
+ * (in pixels) from the optical center to the farthest pixel in the
+ * image.
+ */
+ double getM() const
+ {
+ double cpx = imageSize_.width * cx_;
+ double cpy = imageSize_.height * cy_;
+ double mx = std::max(cpx, std::fabs(imageSize_.width - cpx));
+ double my = std::max(cpy, std::fabs(imageSize_.height - cpy));
+
+ return sqrt(mx * mx + my * my);
+ }
+
+ void setReferenceImageSize(const Size &size)
+ {
+ imageSize_ = size;
+ /* Calculate normalized centers */
+ double m = getM();
+ cnx_ = (size.width * cx_) / m;
+ cny_ = (size.height * cy_) / m;
+ }
+
+private:
+ double cx_;
+ double cy_;
+ double cnx_;
+ double cny_;
+ std::array<double, kNumCoefficients> coefficients_;
+
+ Size imageSize_;
+};
+
+} /* namespace ipa */
+
+template<>
+struct YamlObject::Getter<ipa::Polynomial> {
+ std::optional<ipa::Polynomial> get(const YamlObject &obj) const
+ {
+ std::optional<double> cx = obj["cx"].get<double>();
+ std::optional<double> cy = obj["cy"].get<double>();
+ std::optional<double> k0 = obj["k0"].get<double>();
+ std::optional<double> k1 = obj["k1"].get<double>();
+ std::optional<double> k2 = obj["k2"].get<double>();
+ std::optional<double> k3 = obj["k3"].get<double>();
+ std::optional<double> k4 = obj["k4"].get<double>();
+
+ if (!(cx && cy && k0 && k1 && k2 && k3 && k4))
+ LOG(Polynomial, Error) << "Polynomial is missing parameter ";
+
+ return ipa::Polynomial(*cx, *cy, *k0, *k1, *k2, *k3, *k4);
+ }
+};
+
+} /* namespace libcamera */
Add a basic class to represent polynomials as specified in the DNG spec for vignetting correction. Signed-off-by: Stefan Klug <stefan.klug@ideasonboard.com> --- src/ipa/libipa/meson.build | 2 + src/ipa/libipa/polynomial.cpp | 23 ++++++++ src/ipa/libipa/polynomial.h | 107 ++++++++++++++++++++++++++++++++++ 3 files changed, 132 insertions(+) create mode 100644 src/ipa/libipa/polynomial.cpp create mode 100644 src/ipa/libipa/polynomial.h