Boost thread blocking ros::spin

edit

I have a class that has a member variable which is an object of another class

class SuperScanner {
     public:
      SuperScanner(ros::NodeHandle& nh, std::string cameraIP); 
       // Other functions
     private:
      Motor _motor;
      Camera _camera;
     // Other variables and functions
.....
}

Within a function in the SuperScanner class, I'm creating a new thread that invokes image acquisition and then starts the motor motion. The camera needs to start recording before the motion starts, but must continue for a certain duration of time while the motor still moves.To do this, I'm using boost threads.

SuperScanner::getData() {
  boost::function<void()> scanFunc = boost::bind(&Camera::startAcquiring, _camera, scanTime, 
  boost::ref(cameraStatus), boost::ref(_results));

  // Start acquiring
  std::shared_ptr<boost::thread> threadPtr = std::make_shared<boost::thread>(scanFunc);

  // Send motor to target position
  _motor.send();

  // Join thread
  threadPtr->join();

 _log.print("Finished the acquisition");
}

This seems to run into trouble sometimes, with the ros spin thread getting blocked and not executing any callbacks to other topics subscribed to in SuperScanner. The "Finished the acquisition" statement does get printed out though, so I know the thread has joined. A ronsode info on the node shows the list of topics, but says "communication with node failed". Could this have anything to do with the member variables within the instance of the _camera object getting updated in its startAcquiring() function?

Here's how the node gets started:

int main(int argc, char** argv)
{
  ros::init(argc, argv, "super_scanner");
  ros::NodeHandle n("~");

  n.param("/camera_scanner/device_ip", deviceIP, deviceIP);
  SuperScanner superScanner(n, deviceIp);
  ros::spin();
  return 0;
}