PCL Pointcloud type conversion/pointer issue

edit

As I want to get used to the PCL library, I tried to test switching between PointCloud and PointCloud2 types. The node corresponding to the following callback function compiles, but produces a segmentation error. The problem occurs 100% in the code fragment after // OPTIONAL: Perform voxel filtering provided below. It is likely due to making mistakes when converting the types or confusing pointers (kinda new to C++). Any help is appreciated.

void 
cloud_cb (const sensor_msgs::PointCloud2ConstPtr& input)
{
  // convert sensor_msgs to PointCloud
  pcl::PointCloud<pcl::PointXYZ> cloud;
  pcl::fromROSMsg (*input, cloud);

  // //////////////////////////////////////////////////////////////
  // OPTIONAL: Perform voxel filtering
  pcl::PCLPointCloud2Ptr cloud_unfiltered;
  pcl::toPCLPointCloud2(cloud, *cloud_unfiltered); // LINE 29!!
  pcl::PCLPointCloud2ConstPtr cloudPtr(cloud_unfiltered);
  pcl::PCLPointCloud2 cloud_filtered;

  pcl::VoxelGrid<pcl::PCLPointCloud2> sor;
  sor.setInputCloud (cloudPtr);
  sor.setLeafSize (0.1, 0.1, 0.1);
  sor.filter (cloud_filtered);

  pcl::fromPCLPointCloud2(cloud_filtered, cloud);
  // /////////////////////////////////////////////////////////////

gdb backtrace:

    Program received signal SIGSEGV, Segmentation fault.
    0x0000000000413a36 in pcl::toPCLPointCloud2<pcl::PointXYZ> (cloud=..., msg=...)
        at /usr/include/pcl-1.7/pcl/conversions.h:248
    248       msg.height = cloud.height;
    (gdb) bt
    #0  0x0000000000413a36 in pcl::toPCLPointCloud2<pcl::PointXYZ> (cloud=..., 
        msg=...) at /usr/include/pcl-1.7/pcl/conversions.h:248
    #1  0x000000000040d498 in cloud_cb (input=...)
        at /home/mma7rng/catkin_ws/src/pcl_planar_segmentation/src/pcl_planar_segmentation_node.cpp:29
    #2  0x0000000000411b4b in operator() (a0=..., this=<optimized out>)
        at /usr/include/boost/function/function_template.hpp:767
    #3  boost::detail::function::void_function_obj_invoker1<boost::function<void (boost::shared_ptr<sensor_msgs::PointCloud2_<std::allocator<void> > const> const&)>, void, boost::shared_ptr<sensor_msgs::PointCloud2_<std::allocator<void> > const> >::invoke(boost::detail::function::function_buffer&, boost::shared_ptr<sensor_msgs::PointCloud2_<std::allocator<void> > const>) (function_obj_ptr=..., 
        a0=...) at /usr/include/boost/function/function_template.hpp:153
    #4  0x00000000004168d8 in operator() (a0=..., this=0x6360b8)
        at /usr/include/boost/function/function_template.hpp:767
    #5  ros::SubscriptionCallbackHelperT<boost::shared_ptr<sensor_msgs::PointCloud2_<std::allocator<void> > const> const&, void>::call (this=0x6360b0, params=...)
        at /opt/ros/jade/include/ros/subscription_callback_helper.h:144
    #6  0x00007ffff646a6b5 in ros::SubscriptionQueue::call() ()
       from /opt/ros/jade/lib/libroscpp.so
    #7  0x00007ffff6424107 in ros::CallbackQueue::callOneCB(ros::CallbackQueue::TLS*) () from /opt/ros/jade/lib/libroscpp.so
    #8  0x00007ffff6424c33 in ros::CallbackQueue::callAvailable(ros::WallDuration)
() from /opt/ros/jade/lib/libroscpp.so
#9  0x00007ffff646d1e5 in ros::SingleThreadedSpinner::spin(ros::CallbackQueue*)
    () from /opt/ros/jade/lib/libroscpp.so
#10 0x00007ffff6454e0b in ros::spin() () from /opt/ros/jade/lib/libroscpp.so
#11 0x000000000040cea9 in main (argc=1, argv=0x7fffffffd948)
    at /home/mma7rng/catkin_ws/src/pcl_planar_segmentation/src/pcl_planar_segmentation_node.cpp:107