mycobot_ros/src/opencv_camera.cpp

#include <ros/ros.h>  
#include <image_transport/image_transport.h>  
#include <opencv2/highgui/highgui.hpp>  
#include <cv_bridge/cv_bridge.h>  
#include <sstream> // for converting the command line parameter to integer  

int main(int argc, char** argv)  
{  
    // Check if video source has been passed as a parameter  
    if(argv[1] == NULL)   
    {  
        ROS_INFO("argv[1]=NULL\n");  
        return 1;  
    }  

    ros::init(argc, argv, "image_publisher"); // Initialize node
    ros::NodeHandle nh;  
    image_transport::ImageTransport it(nh);  
    image_transport::Publisher pub = it.advertise("camera/image", 1);  // Publish topic

    ros::Rate loop_rate(200); // refresh Hz.

    // Convert the passed as command line parameter index for the video device to an integer  
    std::istringstream video_sourceCmd(argv[1]);  
    int video_source;  
    // Check if it is indeed a number  
    if(!(video_sourceCmd >> video_source))   
    {  
        ROS_INFO("video_sourceCmd is %d\n",video_source);  
        return 1;  
    }  

    cv::VideoCapture cap(video_source);  
    // Check if video device can be opened with the given index  
    if(!cap.isOpened())   
    {  
        ROS_INFO("can not opencv video device\n");  
        return 1;  
    }  
    cv::Mat frame;  
    sensor_msgs::ImagePtr msg;  

    while (nh.ok()) 
    {  
        cap >> frame;  
        // cv::imshow("veiwer", frame);
        // Check if grabbed frame is actually full with some content  
        if(!frame.empty()) 
        {  
            msg = cv_bridge::CvImage(std_msgs::Header(), "bgr8", frame).toImageMsg();  
            pub.publish(msg);  
            //cv::Wait(1);  
    	}  
        ros::spinOnce();  
        loop_rate.sleep();  
        // if(cv::waitKey(2) >= 0)
            // break;
    }
    
}