PCL 函数概括

1、pcl::getMinMax3D  

功能：所有点中最小的x值，y值，z值，输出当前点云所有点中最大的x值，y值，z值。

这个是给点云深度上色很重要的一个参数，需要注意的是这个函数输出的只是这个点云分别是x,y,z 的最大最小值而不是点

pcl源码：

template  inline void
pcl::getMinMax3D (const pcl::PointCloud &cloud, PointT &min_pt, PointT &max_pt)
{
  Eigen::Array4f min_p, max_p;
  min_p.setConstant (FLT_MAX);
  max_p.setConstant (-FLT_MAX);

  // If the data is dense, we don't need to check for NaN
  if (cloud.is_dense)
  {
    for (size_t i = 0; i < cloud.points.size (); ++i)
    {
      pcl::Array4fMapConst pt = cloud.points[i].getArray4fMap ();
      min_p = min_p.min (pt);
      max_p = max_p.max (pt);
    }
  }
  // NaN or Inf values could exist => check for them
  else
  {
    for (size_t i = 0; i < cloud.points.size (); ++i)
    {
      // Check if the point is invalid
      if (!pcl_isfinite (cloud.points[i].x) || 
          !pcl_isfinite (cloud.points[i].y) || 
          !pcl_isfinite (cloud.points[i].z))
        continue;
      pcl::Array4fMapConst pt = cloud.points[i].getArray4fMap ();
      min_p = min_p.min (pt);
      max_p = max_p.max (pt);
    }
  }
  min_pt.x = min_p[0]; min_pt.y = min_p[1]; min_pt.z = min_p[2];
  max_pt.x = max_p[0]; max_pt.y = max_p[1]; max_pt.z = max_p[2];
}