Method Normalize

examples/bal_problem.cc:248–291

}

void BALProblem::Normalize() {
  // Compute the marginal median of the geometry.
  std::vector<double> tmp(num_points_);
  Eigen::Vector3d median;
  double* points = mutable_points();
  for (int i = 0; i < 3; ++i) {
    for (int j = 0; j < num_points_; ++j) {
      tmp[j] = points[3 * j + i];
    }
    median(i) = Median(&tmp);
  }

  for (int i = 0; i < num_points_; ++i) {
    VectorRef point(points + 3 * i, 3);
    tmp[i] = (point - median).lpNorm<1>();
  }

  const double median_absolute_deviation = Median(&tmp);

  // Scale so that the median absolute deviation of the resulting
  // reconstruction is 100.
  const double scale = 100.0 / median_absolute_deviation;

  VLOG(2) << "median: " << median.transpose();
  VLOG(2) << "median absolute deviation: " << median_absolute_deviation;
  VLOG(2) << "scale: " << scale;

  // X = scale * (X - median)
  for (int i = 0; i < num_points_; ++i) {
    VectorRef point(points + 3 * i, 3);
    point = scale * (point - median);
  }

  double* cameras = mutable_cameras();
  double angle_axis[3];
  double center[3];
  for (int i = 0; i < num_cameras_; ++i) {
    double* camera = cameras + camera_block_size() * i;
    CameraToAngleAxisAndCenter(camera, angle_axis, center);
    // center = scale * (center - median)
    VectorRef(center, 3) = scale * (VectorRef(center, 3) - median);
    AngleAxisAndCenterToCamera(angle_axis, center, camera);
  }
}

void BALProblem::Perturb(const double rotation_sigma,
                         const double translation_sigma,