ros_hydro_OpenCV_kinect_imageconverter

1.创建好的工作空间catkin_ws

2.创建程序包beginner_opencv,注意其依赖项

cd ~/catkin_ws/src

catkin_create_pkg beginner_opencv sensor_msgs cv_bridge roscpp std_msgs image_transport

3.编写节点image_converter.cpp及相关配置

cd beginner_opencv/src

gedit image_converter.cpp

加入内容，其中接受话题是 /camera/rgb/image_color，表明使用kinect摄像头。

#include <ros/ros.h>

#include <image_transport/image_transport.h>

#include <cv_bridge/cv_bridge.h>

#include <sensor_msgs/image_encodings.h>

#include <opencv2/imgproc/imgproc.hpp>

#include <opencv2/highgui/highgui.hpp>

static const std::string OPENCV_WINDOW = "Image window";

class ImageConverter

{

ros::NodeHandle nh_;

image_transport::ImageTransport it_;

image_transport::Subscriber image_sub_;

image_transport::Publisher image_pub_;

public:

ImageConverter()

: it_(nh_)

{

// Subscrive to input video feed and publish output video feed

image_sub_ = it_.subscribe("/camera/rgb/image_color", 1,

&ImageConverter::imageCb, this);

image_pub_ = it_.advertise("/image_converter/output_video", 1);

cv::namedWindow(OPENCV_WINDOW);

}

~ImageConverter()

{

cv::destroyWindow(OPENCV_WINDOW);

}

void imageCb(const sensor_msgs::ImageConstPtr& msg)

{

cv_bridge::CvImagePtr cv_ptr;

try

{

cv_ptr = cv_bridge::toCvCopy(msg, sensor_msgs::image_encodings::BGR8);

}

catch (cv_bridge::Exception& e)

{

ROS_ERROR("cv_bridge exception: %s", e.what());

return;

}

// Draw an example circle on the video stream

if (cv_ptr->image.rows > 60 && cv_ptr->image.cols > 60)

cv::circle(cv_ptr->image, cv::Point(50, 50), 10, CV_RGB(255,0,0));

// Update GUI Window

cv::imshow(OPENCV_WINDOW, cv_ptr->image);

cv::waitKey(3);

// Output modified video stream

image_pub_.publish(cv_ptr->toImageMsg());

}

};

int main(int argc, char** argv)

{

ros::init(argc, argv, "image_converter");

ImageConverter ic;

ros::spin();

return 0;

}

4.配置

CMakeLists.txt中加入

add_executable(image_converter src/image_converter.cpp)

add_dependencies(image_converter beginner_opencv_generate_messages_cpp)

target_link_libraries(image_converter

${catkin_LIBRARIES}

)

5.编译

cd ~/catkin_ws

catkin_make

6.运行

source devel/setup.bash

rosrun beginner_opencv image_converter

7.出错

[rosrun] Couldn't find executable named image_converter below /home/hsn/catkin_ws/src/beginner_opencv

解决

原来是工作空间里其他的程序包出了问题，导致编译出错，编译停止，其他程序包就不会再编译。排除掉出错的程序包就可以啦！
http://wiki.ros.org/cv_bridge/Tutorials/UsingCvBridgeToConvertBetweenROSImagesAndOpenCVImages