Converting CvImage to a ROS image not working on Ubuntu 18.04 - Melodic
Hello, I am trying to convert a CvImage
to a ROS
image.
I followed the tutorial present on this source but I don't understand the error that is keeping me from compiling and running the example.
Below the code I am using from the same tutorial:
UPDATE CMake
Code:
cmake_minimum_required(VERSION 2.8.3)
project(map_ros)
add_compile_options(-std=c++11)
find_package(octomap REQUIRED)
set(CMAKE_MODULE_PATH ${PROJECT_SOURCE_DIR})
find_package(Eigen3 REQUIRED)
include_directories(${EIGEN3_INCLUDE_DIR})
find_package(catkin REQUIRED COMPONENTS
roscpp
sensor_msgs
std_msgs
message_generation
pcl_ros
pcl_conversions
geometry_msgs
nav_msgs
grid_map_core
grid_map_ros
grid_map_cv
grid_map_filters
grid_map_loader
grid_map_msgs
grid_map_octomap
grid_map_rviz_plugin
grid_map_visualization
cv_bridge
octomap_msgs
filters
image_transport
)
catkin_package(
INCLUDE_DIRS include
LIBRARIES ${PROJECT_NAME}
CATKIN_DEPENDS
roscpp
sensor_msgs
std_msgs
message_generation
pcl_ros
pcl_conversions
geometry_msgs
nav_msgs
grid_map_core
grid_map_ros
grid_map_cv
grid_map_filters
grid_map_loader
grid_map_msgs
grid_map_octomap
grid_map_rviz_plugin
grid_map_visualization
cv_bridge
octomap_msgs
filters
DEPENDS EIGEN3
)
###########
## Build ##
###########
include_directories(${catkin_INCLUDE_DIRS})
add_executable(imageConverter src/imageConverter.cpp ${SRCS})
target_link_libraries(imageConverter ${catkin_LIBRARIES})
And the C++ code I am using:
#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/image_raw", 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;
}
Here the errors which states that a bunch of undefined references are found:
[100%] Built target rviz_imu_plugin
CMakeFiles/imageConverter.dir/src/imageConverter.cpp.o: In function `ImageConverter::ImageConverter()':
/home/emanuele/catkin_ws/src/map_ros/src/imageConverter.cpp:89: undefined reference to `cv::namedWindow(cv::String const&, int)'
CMakeFiles/imageConverter.dir/src/imageConverter.cpp.o: In function `ImageConverter::~ImageConverter()':
/home/emanuele/catkin_ws/src/map_ros/src/imageConverter.cpp:94: undefined reference to `cv::destroyWindow(cv::String const&)'
CMakeFiles/imageConverter.dir/src/imageConverter.cpp.o: In function `ImageConverter::imageCb(boost::shared_ptr<sensor_msgs::Image_<std::allocator<void> > const> const&)':
/home/emanuele/catkin_ws/src/map_ros/src/imageConverter.cpp:115: undefined reference to `cv::imshow(cv::String const&, cv::_InputArray const&)'
/home/emanuele/catkin_ws/src/map_ros/src/imageConverter.cpp:116: undefined reference to `cv::waitKey(int)'
collect2: error: ld returned 1 exit status
map_ros/CMakeFiles/imageConverter.dir/build.make:334: recipe for target '/home/emanuele/catkin_ws/devel/lib/map_ros/imageConverter' failed
make[2]: *** [/home/emanuele/catkin_ws/devel/lib/map_ros/imageConverter] Error 1
CMakeFiles/Makefile2:9236: recipe for target 'map_ros/CMakeFiles/imageConverter.dir/all' failed
make[1]: *** [map_ros/CMakeFiles/imageConverter.dir ...
this is a linker error. You probably forgot to specify
target_link_libraries
correctly in youCMakeLists.txt
. Please update your question with the content of yourCMakeLists.txt
(and please keep it concise, i.e. remove all unnecessary comments)@mgruhler, thank you very much for reading the question. I updated the question inserting the small
CMake
code I am using.