Camera Access Issue When Using Boost Stream in OSX

Question

I am trying to use OpenCV to open a camera. This works great when I open the camera in the main thread, but when I try to open the camera while in the Boost stream, it fails. I could not understand why this is happening. I guess this has something to do with Boost stream permissions.

The following works great:

#include <cv.h> #include <boost/thread.hpp> #include <highgui.h> using namespace cv; void openCamera() { Ptr< VideoCapture > capPtr(new VideoCapture(0)); // open the default camera } int main() { openCamera(); } 

And my camera turns on quickly, after which I get the message "Cleaned Camera", as expected.

But when I try to do the same through the Boost thread, it does not open the camera:

 #include <cv.h> #include <boost/thread.hpp> #include <highgui.h> #include <iostream> using namespace cv; void openCamera() { std::cout << "confirming that openCamera() was called" << std::endl; Ptr< VideoCapture > capPtr(new VideoCapture(0)); // open the default camera } int main() { boost::thread trackerThread( boost::bind(openCamera) ); } 

It prints a "confirmation that openCamera () was called", but the camera never turns on and the message "Cleaned camera" is missing.

Can this be fixed?

Thanks!

Answer 1

I don’t use boost much, but you don’t have to do something to prevent main () from working while your thread is running? As if...

 int main() { boost::thread trackerThread( boost::bind(openCamera) ); trackerThread.join(); }