scan_shadow_detector.cpp

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/*
\author Atsushi Watanabe (SEQSENSE, Inc.)
*/
 
#include <laser_filters/scan_shadow_detector.h>
#include <math.h>
#include <ros/ros.h>
 
namespace laser_filters
{
  void ScanShadowDetector::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 ScanShadowDetector::isShadow(const float r1, const float r2, const float included_angle)
  {
    float included_angle_sin = sinf(included_angle);
    float included_angle_cos = cosf(included_angle);
    return isShadow(r1, r2, included_angle_sin, included_angle_cos);
  }
 
  bool ScanShadowDetector::isShadow(float r1, float r2, float included_angle_sin, float included_angle_cos)
  {
    const float perpendicular_y_ = r2 * included_angle_sin;
    const float perpendicular_x_ = r1 - r2 * included_angle_cos;
    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;
  }
}