ROS：OpenCV读取摄像头并发布话题

#include <cv_bridge/cv_bridge.h>
#include <image_transport/image_transport.h>
#include <opencv2/highgui/highgui.hpp>
#include <ros/ros.h>
#include <sensor_msgs/image_encodings.h>

int main(int argc, char** argv)
{
    ros::init(argc, argv, "pub_cam_node");
    ros::NodeHandle nh;

    cv::VideoCapture capture(0); //0为读取摄像头，“video.format"为读取本地视频
    if (!capture.isOpened()) {
        ROS_ERROR_STREAM("Failed to open video device\n");
        ros::shutdown();
    }

    //image_transport负责订阅和发布
    image_transport::ImageTransport it(nh);
    image_transport::Publisher pub_image = it.advertise("camera", 1);

    cv::Mat image;//Mat为OpenCV里定义的图像类

    while (ros::ok()) {
        capture >> image; //载入

        if (image.empty()) {
            ROS_ERROR_STREAM("Failed to capture image!");
            ros::shutdown();
        }
        //将图像从cv::Mat类型转化成sensor_msgs/Image类型并发布
        pub_image.publish(cv_bridge::CvImage(std_msgs::Header(), "bgr8", image).toImageMsg());//将图像从sensor_msgs/Image类型转化成cv::Mat类型
        /*
        cv_bridge可以有选择的对颜色和深度信息进行转化。为了使用指定的特征编码，就有下面集中的编码形式：

        mono8:  CV_8UC1， 灰度图像
        mono16: CV_16UC1,16位灰度图像
        bgr8: CV_8UC3,带有颜色信息并且颜色的顺序是BGR顺序
        rgb8: CV_8UC3,带有颜色信息并且颜色的顺序是RGB顺序
        bgra8: CV_8UC4, BGR的彩色图像，并且带alpha通道
        rgba8: CV_8UC4,CV，RGB彩色图像，并且带alpha通道
        */
        cv::imshow("camera", image);
        cv::waitKey(3); // opencv刷新图像 3ms

		ros::spin();
    } 
}

在CMakeLists.txt中添加

find_package(OpenCV REQUIRED)

add_executable(cameraproc
  src/cameraproc.cpp
)
target_link_libraries(cameraproc
  ${catkin_LIBRARIES}
  ${OpenCV_LIBRARIES}
)

其中cameraproc为cpp文件名