我正在尝试使用发布者订阅者 no 通过从我的网络摄像头流式传输图像来运行我的对象识别程序。在我的程序中，我正在使用opencv_dnn库提供的readNetFromTensorflow函数。但是当我catkin_make在我的工作区时，总是弹出此错误：
CMakeFiles/my_subscriber.dir/src/my_subscriber.cpp.o: In function `main':
my_subscriber.cpp:(.text+0x2ee): undefined reference to `cv::dnn::experimental_dnn_v2::readNetFromTensorflow(cv::String const&, cv::String const&)'
my_subscriber.cpp:(.text+0x30e): undefined reference to `cv::dnn::experimental_dnn_v2::Net::setPreferableBackend(int)'
my_subscriber.cpp:(.text+0x31a): undefined reference to `cv::dnn::experimental_dnn_v2::Net::setPreferableTarget(int)'
my_subscriber.cpp:(.text+0x4c4): undefined reference to `cv::dnn::experimental_dnn_v2::Net::~Net()'
my_subscriber.cpp:(.text+0x5f0): undefined reference to `cv::dnn::experimental_dnn_v2::Net::~Net()'
collect2: error: ld returned 1 exit status
image_transport_tutorial/CMakeFiles/my_subscriber.dir/build.make:176: recipe for target '/home/odroid/image_transport_ws/devel/lib/image_transport_tutorial/my_subscriber' failed
make[2]: *** [/home/odroid/image_transport_ws/devel/lib/image_transport_tutorial/my_subscriber] Error 1
CMakeFiles/Makefile2:1125: recipe for target 'image_transport_tutorial/CMakeFiles/my_subscriber.dir/all' failed
make[1]: *** [image_transport_tutorial/CMakeFiles/my_subscriber.dir/all] Error 2
Makefile:138: recipe for target 'all' failed
make: *** [all] Error 2
这是我到目前为止的程序：
#include <ros/ros.h>
#include <image_transport/image_transport.h>
#include <cv_bridge/cv_bridge.h>
#include <opencv2/highgui.hpp>
#include <opencv2/dnn.hpp>
#include <opencv2/calib3d.hpp>
using namespace std;
using namespace cv;
const size_t inWidth = 320;
const size_t inHeight = 320;
const char* classNames[] = {"background",
"A", "B", "C"};
cv_bridge::CvImagePtr cv_ptr;
int h,w;
void imageCallback(const sensor_msgs::ImageConstPtr& msg)
{
try
{
cv_ptr = cv_bridge::toCvCopy(msg, sensor_msgs::image_encodings::BGR8);
w = cv_ptr->image.cols;
h = cv_ptr->image.rows;
cv::waitKey(10);
}
catch (cv_bridge::Exception& e)
{
ROS_ERROR("Could not convert from '%s' to 'bgr8'.", msg->encoding.c_str());
}
}
int main(int argc, char **argv)
{
ros::init(argc, argv, "image_listener");
ros::NodeHandle nh;
cv::namedWindow("view");
cv::startWindowThread();
image_transport::ImageTransport it(nh);
//! [Initialize network]
cv::dnn::Net net = dnn::readNetFromTensorflow("/home/odroid/Desktop/Archive/frozen_inference_graph.pb","/home/odroid/Desktop/Archive/graph.pbtxt");
net.setPreferableBackend(3);
net.setPreferableTarget(1);
//! [Initialize network]
image_transport::Subscriber sub = it.subscribe("camera/image", 1, &imageCallback);
//cv::Mat inputBlob = cv::dnn::blobFromImage(cv_ptr->image,1.0, Size(inWidth,inHeight),Scalar(127.5,127.5,127.5), true,false); //Convert Mat to batch of images
//net.setInput(inputBlob);
//Mat detection = net.forward();
ros::spin();
cv::destroyWindow("view");
}
如果我评论 cv：:d nn：：Net，我可以构建 100% 完成。
这是我的CMakeLists.txt：
cmake_minimum_required(VERSION 3.1)
#Enable C++11
set(CMAKE_CXX_STANDARD 11)
set(CMAKE_CXX_STANDARD_REQUIRED TRUE)
project(image_transport_tutorial)
find_package(catkin REQUIRED COMPONENTS cv_bridge image_transport message_generation sensor_msgs)
# add the resized image message
add_message_files(DIRECTORY msg
FILES ResizedImage.msg
)
generate_messages(DEPENDENCIES sensor_msgs)
catkin_package(CATKIN_DEPENDS cv_bridge image_transport message_runtime sensor_msgs)
find_package(OpenCV REQUIRED)
#Set OpenCV
set(OpenCV_INCLUDE_DIRS /usr/local/include/ /usr/local/include/opencv2/)
#Print some message showing some of them
message(STATUS "OpenCV library status:")
message(STATUS "config: ${OpenCV_DIR}")
message(STATUS "version: ${OpenCV_VERSION}")
message(STATUS "libraries: ${OpenCV_LIBRARIES}")
message(STATUS "include path: ${OpenCV_INCLUDE_DIRS}")
include_directories(include ${catkin_INCLUDE_DIRS} ${OpenCV_INCLUDE_DIRS})
# add the publisher example
add_executable(my_publisher src/my_publisher.cpp)
add_dependencies(my_publisher ${catkin_EXPORTED_TARGETS} ${${PROJECT_NAME}_EXPORTED_TARGETS})
target_link_libraries(my_publisher ${catkin_LIBRARIES} ${OpenCV_LIBRARIES})
# add the subscriber example
add_executable(my_subscriber src/my_subscriber.cpp)
add_dependencies(my_subscriber ${catkin_EXPORTED_TARGETS} ${${PROJECT_NAME}_EXPORTED_TARGETS})
target_link_libraries(my_subscriber ${catkin_LIBRARIES} ${OpenCV_LIBRARIES})
# add the plugin example
add_library(resized_publisher src/manifest.cpp src/resized_publisher.cpp src/resized_subscriber.cpp)
add_dependencies(resized_publisher ${catkin_EXPORTED_TARGETS} ${${PROJECT_NAME}_EXPORTED_TARGETS})
target_link_libraries(resized_publisher ${catkin_LIBRARIES} ${OpenCV_LIBRARIES})
# Mark executables and/or libraries for installation
install(TARGETS my_publisher my_subscriber resized_publisher
ARCHIVE DESTINATION ${CATKIN_PACKAGE_LIB_DESTINATION}
LIBRARY DESTINATION ${CATKIN_PACKAGE_LIB_DESTINATION}
RUNTIME DESTINATION ${CATKIN_PACKAGE_BIN_DESTINATION}
)
install(DIRECTORY launch/
DESTINATION ${CATKIN_PACKAGE_SHARE_DESTINATION}/launch
)
install(DIRECTORY model/
DESTINATION ${CATKIN_PACKAGE_SHARE_DESTINATION}/model
)
install(FILES resized_plugins.xml
DESTINATION ${CATKIN_PACKAGE_SHARE_DESTINATION}
)
**
更新：
**
如果我使用 opencv 3.3.1 catkin_make，它是在我安装 ROS Kinetic 时构建的，我可以 100% 成功编译它。但是当我做一些rosrun时，它会导致一些错误。这是错误：
Preprocessor/sub:Sub(Preprocessor/mul)(Preprocessor/sub/y) OpenCV Error: Unspecified error (Unknown layer type Sub in op Preprocessor/sub) in populateNet, file /tmp/binarydeb/ros-kinetic-opencv3-3.3.1/modules/dnn/src/tensorflow/tf_importer.cpp, line 1311
我做了几天的浏览，发现一个人说这是因为ROS附带的opencv cv_bridge和image_transport。这里的链接：https：//answers.ros.org/question/318146/using-opencv-dnn-module-with-ros/
请帮助我，任何帮助将不胜感激。
我终于解决了这个问题，这里是解决方案：
$ cd ~/catkin_ws
$ git clone https://github.com/ros-perception/vision_opencv src/vision_opencv
$ git clone https://github.com/ros-perception/image_transport_plugins.git src/image_transport_plugins
$ catkin_make
唰唰！