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// Copyright (c) 2014 libmv authors.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to
// deal in the Software without restriction, including without limitation the
// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
// sell copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
// IN THE SOFTWARE.
#ifndef LIBMV_SIMPLE_PIPELINE_DISTORTION_MODELS_H_
#define LIBMV_SIMPLE_PIPELINE_DISTORTION_MODELS_H_
#include <algorithm>
namespace libmv {
enum DistortionModelType {
DISTORTION_MODEL_POLYNOMIAL,
DISTORTION_MODEL_DIVISION,
DISTORTION_MODEL_NUKE,
};
// Invert camera intrinsics on the image point to get normalized coordinates.
// This inverts the radial lens distortion to a point which is in image pixel
// coordinates to get normalized coordinates.
void InvertPolynomialDistortionModel(const double focal_length_x,
const double focal_length_y,
const double principal_point_x,
const double principal_point_y,
const double k1,
const double k2,
const double k3,
const double p1,
const double p2,
const double image_x,
const double image_y,
double *normalized_x,
double *normalized_y);
// Apply camera intrinsics to the normalized point to get image coordinates.
// This applies the radial lens distortion to a point which is in normalized
// camera coordinates (i.e. the principal point is at (0, 0)) to get image
// coordinates in pixels. Templated for use with autodifferentiation.
template <typename T>
inline void ApplyPolynomialDistortionModel(const T &focal_length_x,
const T &focal_length_y,
const T &principal_point_x,
const T &principal_point_y,
const T &k1,
const T &k2,
const T &k3,
const T &p1,
const T &p2,
const T &normalized_x,
const T &normalized_y,
T *image_x,
T *image_y) {
T x = normalized_x;
T y = normalized_y;
// Apply distortion to the normalized points to get (xd, yd).
T r2 = x*x + y*y;
T r4 = r2 * r2;
T r6 = r4 * r2;
T r_coeff = (T(1) + k1*r2 + k2*r4 + k3*r6);
T xd = x * r_coeff + T(2)*p1*x*y + p2*(r2 + T(2)*x*x);
T yd = y * r_coeff + T(2)*p2*x*y + p1*(r2 + T(2)*y*y);
// Apply focal length and principal point to get the final image coordinates.
*image_x = focal_length_x * xd + principal_point_x;
*image_y = focal_length_y * yd + principal_point_y;
}
// Invert camera intrinsics on the image point to get normalized coordinates.
// This inverts the radial lens distortion to a point which is in image pixel
// coordinates to get normalized coordinates.
//
// Uses division distortion model.
void InvertDivisionDistortionModel(const double focal_length_x,
const double focal_length_y,
const double principal_point_x,
const double principal_point_y,
const double k1,
const double k2,
const double image_x,
const double image_y,
double *normalized_x,
double *normalized_y);
// Apply camera intrinsics to the normalized point to get image coordinates.
// This applies the radial lens distortion to a point which is in normalized
// camera coordinates (i.e. the principal point is at (0, 0)) to get image
// coordinates in pixels. Templated for use with autodifferentiation.
//
// Uses division distortion model.
template <typename T>
inline void ApplyDivisionDistortionModel(const T &focal_length_x,
const T &focal_length_y,
const T &principal_point_x,
const T &principal_point_y,
const T &k1,
const T &k2,
const T &normalized_x,
const T &normalized_y,
T *image_x,
T *image_y) {
T x = normalized_x;
T y = normalized_y;
T r2 = x*x + y*y;
T r4 = r2 * r2;
T xd = x / (T(1) + k1 * r2 + k2 * r4);
T yd = y / (T(1) + k1 * r2 + k2 * r4);
// Apply focal length and principal point to get the final image coordinates.
*image_x = focal_length_x * xd + principal_point_x;
*image_y = focal_length_y * yd + principal_point_y;
}
// Invert camera intrinsics on the image point to get normalized coordinates.
// This inverts the radial lens distortion to a point which is in image pixel
// coordinates to get normalized coordinates.
//
// Uses Nuke distortion model.
template <typename T>
void InvertNukeDistortionModel(const T &focal_length_x,
const T &focal_length_y,
const T &principal_point_x,
const T &principal_point_y,
const int image_width,
const int image_height,
const T &k1,
const T &k2,
const T &image_x,
const T &image_y,
T *normalized_x,
T *normalized_y) {
// According to the documentation:
//
// xu = xd / (1 + k0 * rd^2 + k1 * rd^4)
// yu = yd / (1 + k0 * rd^2 + k1 * rd^4)
//
// Legend:
// (xd, yd) are the distorted cartesian coordinates,
// (rd, phid) are the distorted polar coordinates,
// (xu, yu) are the undistorted cartesian coordinates,
// (ru, phiu) are the undistorted polar coordinates,
// the k-values are the distortion coefficients.
//
// The coordinate systems are relative to the distortion centre.
const int max_image_size = std::max(image_width, image_height);
const double max_half_image_size = max_image_size * 0.5;
if (max_half_image_size == 0.0) {
*normalized_x = image_x * max_half_image_size / focal_length_x;
*normalized_y = image_y * max_half_image_size / focal_length_y;
return;
}
const T xd = (image_x - principal_point_x) / max_half_image_size;
const T yd = (image_y - principal_point_y) / max_half_image_size;
T rd2 = xd*xd + yd*yd;
T rd4 = rd2 * rd2;
T r_coeff = T(1) / (T(1) + k1*rd2 + k2*rd4);
T xu = xd * r_coeff;
T yu = yd * r_coeff;
*normalized_x = xu * max_half_image_size / focal_length_x;
*normalized_y = yu * max_half_image_size / focal_length_y;
}
// Apply camera intrinsics to the normalized point to get image coordinates.
// This applies the radial lens distortion to a point which is in normalized
// camera coordinates (i.e. the principal point is at (0, 0)) to get image
// coordinates in pixels. Templated for use with autodifferentiation.
//
// Uses Nuke distortion model.
void ApplyNukeDistortionModel(const double focal_length_x,
const double focal_length_y,
const double principal_point_x,
const double principal_point_y,
const int image_width,
const int image_height,
const double k1,
const double k2,
const double normalized_x,
const double normalized_y,
double *image_x,
double *image_y);
} // namespace libmv
#endif // LIBMV_SIMPLE_PIPELINE_DISTORTION_MODELS_H_
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