scan_shadow_detector.h

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/*
\author Atsushi Watanabe (SEQSENSE, Inc.)
*/

#ifndef SCAN_SHADOW_DETECTOR_H
#define SCAN_SHADOW_DETECTOR_H

namespace laser_filters
{
class ScanShadowDetector
{
public:
  float min_angle_tan_, max_angle_tan_;  // Filter angle thresholds

  void configure(const float min_angle, const float max_angle)
  {
    min_angle_tan_ = tanf(min_angle);
    max_angle_tan_ = tanf(max_angle);

    // Correct sign of tan around singularity points
    if (min_angle_tan_ < 0.0)
      min_angle_tan_ = -min_angle_tan_;
    if (max_angle_tan_ > 0.0)
      max_angle_tan_ = -max_angle_tan_;
  }
  bool isShadow(const float r1, const float r2, const float included_angle)
  {
    const float perpendicular_y_ = r2 * sinf(included_angle);
    const float perpendicular_x_ = r1 - r2 * cosf(included_angle);
    const float perpendicular_tan_ = fabs(perpendicular_y_) / perpendicular_x_;

    if (perpendicular_tan_ > 0)
    {
      if (perpendicular_tan_ < min_angle_tan_)
        return true;
    }
    else
    {
      if (perpendicular_tan_ > max_angle_tan_)
        return true;
    }
    return false;
  }
};
}

#endif  //SCAN_SHADOW_DETECTOR_H