SVO-13-vo_node–2021.2.22

vo_node.cpp

#include <ros/package.h>
#include <string>
#include <svo/frame_handler_mono.h>
#include <svo/map.h>
#include <svo/config.h>
#include <svo_ros/visualizer.h>
#include <vikit/params_helper.h>
#include <sensor_msgs/Image.h>
#include <sensor_msgs/Imu.h>
#include <std_msgs/String.h>
#include <message_filters/subscriber.h>
#include <message_filters/synchronizer.h>
#include <message_filters/sync_policies/approximate_time.h>
#include <image_transport/image_transport.h>
#include <boost/thread.hpp>
#include <cv_bridge/cv_bridge.h>
#include <Eigen/Core>
#include <vikit/abstract_camera.h>
#include <vikit/camera_loader.h>
#include <vikit/user_input_thread.h>

namespace svo{
  
class VoNode{
public:
  svo::FrameHandlerMono* vo_;
  svo::Visualizer visualizer_;
  bool publish_markers_;
  
  bool publish_dense_input_;
  
  //首先开辟了一个线程,用于监听控制台输入
  boost::shared_ptr<vk::UserInputThread> user_input_thread_;
  ros::Subscriber sub_remote_key_;
  std::string remote_input_;
  vk::AbstractCamera* cam_;//加载摄像机参数
  bool quit_;//是否退出
  VoNode();
  ~VoNode();
  
  void imgCb(const sensor_msgs::ImageConstPtr& msg);
  void processUserActions();
  void remoteKeyCb(const std_msgs::StringConstPtr& key_input);
};

svo::VoNode::VoNode():
  vo_(NULL),
  publish_markers_(vk::getParam<bool>("svo/publish_markers_",true)),
  publish_dense_input_(vk::getParam<bool>("svo/publish_dense_input_",false)),
  remote_input_(""),
  cam_(NULL),
  quit_(false){
    if(vk::getParam<bool>("svo/accept_console_user_input",true))
      user_input_thread_ = boost::make_shared<vk::UserInputThread>();
    
    if(!vk::camera_loader::loadFromRosNs("svo",cam_))
      throw std::runtime_error("camera model not correctlt specified");
    
    //初始化位姿,Sophus::SE3()用来构建一个欧式群
    visualizer_.T_world_from_vision_ = Sophus::SE3(
      
      //将欧拉角转化为旋转矩阵
      vk::rpy2dcm(Vector3d(vk::getParam<double>("svo/init_rx", 0.0),
                           vk::getParam<double>("svo/init_ry", 0.0),
                           vk::getParam<double>("svo/init_rz", 0.0))),
      Eigen::Vector3d(vk::getParam<double>("svo/init_tx", 0.0),
                      vk::getParam<double>("svo/init_ty", 0.0),
                      vk::getParam<double>("svo/init_tz", 0.0)));
    
    vo_ = new svo::FrameHandlerMono(cam_);//初始化视觉前端VO
    //对应视觉前端VO开始运行系统
    vo_ -> start();//开始
}

VoNode::~VoNode()
{
  delete vo_;
  delete cam_;
  if(user_input_thread_ != NULL)
    user_input_thread_->stop();
}

void VoNode::imgCb(const sensor_msgs::ImageConstPtr& msg)
{
  cv::Mat img;
  try {
    //完成图片的读取
    //将ROS数据转换为opencv中的图像数据
    img = cv_bridge::toCvShare(msg, "mono8")->image;
  } catch (cv_bridge::Exception& e) {
    ROS_ERROR("cv_bridge exception: %s", e.what());
  }
  processUserActions();//执行此函数,开辟控制台输入线程,根据输入字母进行操作
  
  //调用视觉前端类传入图像
  vo_->addImage(img, msg->header.stamp.toSec());//参数2可以获得系统时间
  
  //进行ROS消息有关的设置
  visualizer_.publishMinimal(img, vo_->lastFrame(), *vo_, msg->header.stamp.toSec());

  if(publish_markers_ && vo_->stage() != FrameHandlerBase::STAGE_PAUSED)
    
    //进行关键帧显示
    visualizer_.visualizeMarkers(vo_->lastFrame(), vo_->coreKeyframes(), vo_->map());

  if(publish_dense_input_)
    visualizer_.exportToDense(vo_->lastFrame());//稠密显示特征点

  if(vo_->stage() == FrameHandlerMono::STAGE_PAUSED)
    usleep(100000);
}

void VoNode::processUserActions()
{
  char input = remote_input_.c_str()[0];
  remote_input_ = "";

  if(user_input_thread_ != NULL)
  {
    char console_input = user_input_thread_->getInput();
    if(console_input != 0)
      input = console_input;
  }

  switch(input)
  {
    case 'q':
      quit_ = true;
      printf("SVO user input: QUIT\n");
      break;
    case 'r':
      vo_->reset();
      printf("SVO user input: RESET\n");
      break;
    case 's':
      vo_->start();
      printf("SVO user input: START\n");
      break;
    default: ;
  }
}

void VoNode::remoteKeyCb(const std_msgs::StringConstPtr& key_input)
{
  remote_input_ = key_input->data;
}

} // namespace svo

int main(int argc, char **argv)
{
  ros::init(argc, argv, "svo");//初始化ROS
  ros::NodeHandle nh;//创建句柄
  std::cout << "create vo_node" << std::endl;
  svo::VoNode vo_node;//创建节点vo_node

  // subscribe to cam msgs
  //订阅相机消息
  //先定义topic名称
  std::string cam_topic(vk::getParam<std::string>("svo/cam_topic", "camera/image_raw"));
  image_transport::ImageTransport it(nh);//创建图片的发布/订阅器,名为it
  
  //调用Image_transport::subscriber函数
  //对于节点vo_node,一旦有图像发布到主题cam_topic上,执行回调函数imgCb
  image_transport::Subscriber it_sub = it.subscribe(cam_topic, 5, &svo::VoNode::imgCb, &vo_node);

  // subscribe to remote input
  //订阅远程输入消息
  vo_node.sub_remote_key_ = nh.subscribe("svo/remote_key", 5, &svo::VoNode::remoteKeyCb, &vo_node);

  // start processing callbacks
  while(ros::ok() && !vo_node.quit_)
  {
    ros::spinOnce();
    // TODO check when last image was processed. when too long ago. publish warning that no msgs are received!
  }

  printf("SVO terminated.\n");
  return 0;
}