Gumstix, uvc_camera and cv_capture

edit

I've observed something surprising with a small UVC camera on the gumstix overo. If I use the camera_node from uvc_camera, I get barely 2 fps in 640x480. On the other hand, if I make a small application using the opencv cvCapture function, I get close to 10fps at the same resolution.

Here is the cv code in all its complexity:

       CvCapture* capture = 0;
       capture = cvCaptureFromCAM( -1 );
       IplImage *cv_image = NULL;
       ros::Rate loop_rate(10);
       while (ros::ok())
       {
           cv_image = cvQueryFrame(capture);
           try {
               image_pub_.publish(bridge_.cvToImgMsg(cv_image, "bgr8"));
           } catch (sensor_msgs::CvBridgeException error) {
               ROS_ERROR("error");
           }
           ros::spinOnce();
           loop_rate.sleep();
       }

       cvReleaseCapture(&capture);

On the same camera on my laptop, both cv_capture and uvc_camera publish at 10 fps.

I guess that means there is something that would need optimisation in the uvc_camera/camera_node, but for now I'll be fine with just reporting :-)