colmap/src/feature/types.cc

// Copyright (c) 2022, ETH Zurich and UNC Chapel Hill.
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// Author: Johannes L. Schoenberger (jsch-at-demuc-dot-de)

#include "feature/types.h"

#include "util/logging.h"

namespace colmap {

FeatureKeypoint::FeatureKeypoint() : FeatureKeypoint(0, 0) {}

FeatureKeypoint::FeatureKeypoint(const float x, const float y)
    : FeatureKeypoint(x, y, 1, 0, 0, 1) {}

FeatureKeypoint::FeatureKeypoint(const float x_, const float y_,
                                 const float scale, const float orientation)
    : x(x_), y(y_) {
  CHECK_GE(scale, 0.0);
  const float scale_cos_orientation = scale * std::cos(orientation);
  const float scale_sin_orientation = scale * std::sin(orientation);
  a11 = scale_cos_orientation;
  a12 = -scale_sin_orientation;
  a21 = scale_sin_orientation;
  a22 = scale_cos_orientation;
}

FeatureKeypoint::FeatureKeypoint(const float x_, const float y_,
                                 const float a11_, const float a12_,
                                 const float a21_, const float a22_)
    : x(x_), y(y_), a11(a11_), a12(a12_), a21(a21_), a22(a22_) {}

FeatureKeypoint FeatureKeypoint::FromParameters(const float x, const float y,
                                                const float scale_x,
                                                const float scale_y,
                                                const float orientation,
                                                const float shear) {
  return FeatureKeypoint(x, y, scale_x * std::cos(orientation),
                         -scale_y * std::sin(orientation + shear),
                         scale_x * std::sin(orientation),
                         scale_y * std::cos(orientation + shear));
}

void FeatureKeypoint::Rescale(const float scale) { Rescale(scale, scale); }

void FeatureKeypoint::Rescale(const float scale_x, const float scale_y) {
  CHECK_GT(scale_x, 0);
  CHECK_GT(scale_y, 0);
  x *= scale_x;
  y *= scale_y;
  a11 *= scale_x;
  a12 *= scale_y;
  a21 *= scale_x;
  a22 *= scale_y;
}

float FeatureKeypoint::ComputeScale() const {
  return (ComputeScaleX() + ComputeScaleY()) / 2.0f;
}

float FeatureKeypoint::ComputeScaleX() const {
  return std::sqrt(a11 * a11 + a21 * a21);
}

float FeatureKeypoint::ComputeScaleY() const {
  return std::sqrt(a12 * a12 + a22 * a22);
}

float FeatureKeypoint::ComputeOrientation() const {
  return std::atan2(a21, a11);
}

float FeatureKeypoint::ComputeShear() const {
  return std::atan2(-a12, a22) - ComputeOrientation();
}

}  // namespace colmap