双目立体视觉（4）- ZED2双目视觉开发理论与实践 with examples 0.1 object detection

国际惯例：Src https://github.com/stereolabs/zed-examples

查看本人系列文章了解ZED2 SDK in Linux build（CUDA 10.0 used）： 双目立体视觉（2）- ZED2 SDK配置 Ubuntu18.04 + ROS melodic_Techblog of HaoWANG-优快云博客_ros zed2

ZED2官方文档：Stereolabs Docs: API Reference, Tutorials, and Integration

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目录

1. Object Detect demo (ROS)

1.1 zed_obj_det_sub_tuttorial.cpp

1.2 CMakeLists.txt

1.3 配置zed_wrapper/params/zed2.yaml

2. 测试

2.1 运行zed2.launch

2.2 查看Topic列表

2.3 查看/zed2/zed_node/obj_det/objects话题内容

2.4 测试demo出错

3. 解决

3.1 分析 

3.2 再次测试

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官方教程C++历程源码阅读及编译使用教程
Building a C++ Application on Linux and Jetson | Stereolabshttps://www.stereolabs.com/docs/app-development/cpp/linux/

 

 

1. Object Detect demo (ROS)

近日收到优快云小伙伴私信求助，ZED相机做物体识别和深度值估计时出现问题，即节点起来之后pipline没有数据，直呼，马老师发生甚摸事了？很简单，三步走。你先这样，然后再这样，最后再那样就可以了。

1.1 zed_obj_det_sub_tuttorial.cpp

/**
 * This tutorial demonstrates how to receive the list of detected objects from a ZED node
 * from the ZED node
 */

#include <ros/ros.h>

#include <zed_interfaces/Object.h>
#include <zed_interfaces/ObjectsStamped.h>

/**
 * Subscriber callbacks. The argument of the callback is a constant pointer to the received message
 */

void objectListCallback(const zed_interfaces::ObjectsStamped::ConstPtr& msg)
{
  ROS_INFO("***** New object list *****");
  for (int i = 0; i < msg->objects.size(); i++)
  {
    if (msg->objects[i].label_id == -1)
      continue;

    ROS_INFO_STREAM(msg->objects[i].label << " [" << msg->objects[i].label_id << "] - Pos. ["
                                          << msg->objects[i].position[0] << "," << msg->objects[i].position[1] << ","
                                          << msg->objects[i].position[2] << "] [m]"
                                          << "- Conf. " << msg->objects[i].confidence
                                          << " - Tracking state: " << static_cast<int>(msg->objects[i].tracking_state));
  }
}

/**
 * Node main function
 */
int main(int argc, char** argv)
{

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

 
  ros::NodeHandle n;

  ros::Subscriber subObjList = n.subscribe("objects", 1, objectListCallback);

  /**
   * ros::spin() will enter a loop, pumping callbacks.  With this version, all
   * callbacks will be called from within this thread (the main one).  ros::spin()
   * will exit when Ctrl-C is pressed, or the node is shutdown by the master.
   */
  ros::spin();

  return 0;
}

代码非常简单，即创建一个obt_det 订阅者节点，callback回调函数用于处理接收到的检测结果。

注意到，  ros::Subscriber subObjList = n.subscribe("objects", 1, objectListCallback);

该节点订阅的Topic是"objects",至于ZED2 SDK发布的Obj是不是该话题我们暂时不得而知。

（一定不是，不然不会出问题。）

1.2 CMakeLists.txt

cmake_minimum_required(VERSION 3.5)
project(zed_obj_det_sub_tutorial)

# if CMAKE_BUILD_TYPE is not specified, take 'Release' as default
IF(NOT CMAKE_BUILD_TYPE)
    SET(CMAKE_BUILD_TYPE Release)
ENDIF(NOT CMAKE_BUILD_TYPE)

## Find catkin and any catkin packages
find_package(catkin REQUIRED COMPONENTS roscpp zed_interfaces)

## Declare a catkin package
catkin_package()

include_directories(include ${catkin_INCLUDE_DIRS})

## Build 
add_executable(zed_obj_det_sub src/zed_obj_det_sub_tutorial.cpp)
target_link_libraries(zed_obj_det_sub ${catkin_LIBRARIES})
add_dependencies(zed_obj_det_sub ${catkin_EXPORTED_TARGETS})

查看CMakerlists文件，发现该节点的依赖和编译设置没有问题。

1.3 配置zed_wrapper/params/zed2.yaml

更改objetc_detection 栏目下的相应内容即可。

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2. 测试

2.1 运行zed2.launch

查看zed2参数配置及初始化结果：

2.2 查看Topic列表

/zed2/zed_node/obj_det/objects没有问题

2.3 查看/zed2/zed_node/obj_det/objects话题内容

2.4 测试demo出错

节点运行没有反应，这就机霸的见鬼了。

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3. 解决

3.1 分析 

节点没问题、话题没问题、ZED2驱动没问题、CUDA没问题。。。

自然而然的想到，可能是obj节点并没有接收到Topic中的消息。

修改代码：

/**
 * This tutorial demonstrates how to receive the list of detected objects from a ZED node
 * from the ZED node
 */

#include <ros/ros.h>

#include <zed_interfaces/Object.h>
#include <zed_interfaces/ObjectsStamped.h>

/**
 * Subscriber callbacks. The argument of the callback is a constant pointer to the received message
 */

void objectListCallback(const zed_interfaces::ObjectsStamped::ConstPtr& msg)
{
  ROS_INFO("***** New object list *****");
  for (int i = 0; i < msg->objects.size(); i++)
  {
    if (msg->objects[i].label_id == -1)
      continue;

    ROS_INFO_STREAM(msg->objects[i].label << " [" << msg->objects[i].label_id << "] - Pos. ["
                                          << msg->objects[i].position[0] << "," << msg->objects[i].position[1] << ","
                                          << msg->objects[i].position[2] << "] [m]"
                                          << "- Conf. " << msg->objects[i].confidence
                                          << " - Tracking state: " << static_cast<int>(msg->objects[i].tracking_state));
  }
}

/**
 * Node main function
 */
int main(int argc, char** argv)
{

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

 
  ros::NodeHandle n;

  ros::Subscriber subObjList = n.subscribe("/zed2/zed_node/obj_det/objects", 1, objectListCallback);

  /**
   * ros::spin() will enter a loop, pumping callbacks.  With this version, all
   * callbacks will be called from within this thread (the main one).  ros::spin()
   * will exit when Ctrl-C is pressed, or the node is shutdown by the master.
   */
  ros::spin();

  return 0;
}

  ros::Subscriber subObjList = n.subscribe("/zed2/zed_node/obj_det/objects", 1, objectListCallback);

重新编译catkin_make + source，再次测试。

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3.2 再次测试

ok,成功

识别结果：

数据结构 -   person 数量 【1】 位置 pos [ x, y ,z ] 单位 米， confidence： 【】