1. 任务描述

      在机器人小车（R023d）上搭载摄像头，摄像头采集图像信息并通过WiFi将信息传递给PC端，然后PC端使用OpenCV对摄像头读取到的视频进行灰度化、高斯滤波、腐蚀、膨胀等处理，使图像分为黑白两色。PC端进行图像信息处理并将处理结果传递为下位机，下位机接收上位机处理的图像信息结果后便会控制小车相应运动，小车运动包含前进、左转、右转、停止。

2. 电子硬件

在这个示例中，我们采用了以下硬件，请大家参考：

3. 功能实现

视觉小车巡黑线工作原理：

      (1) 摄像头采集图像信息；

      (2) 通过 WiFi 将图像信息传递给 PC 端（VS2015 配置的 OpenCV 环境）；

      (3) 在 PC 端使用 OpenCV 对摄像头读取到的视频进行灰度化、高斯滤波、腐蚀、膨胀等处理，使图像分为黑白两色，采用 RGB 颜色模型作为黑白颜色判断；

      (4) 将图像对称分成左右两半，分别判断左、右计算检测在显示的摄像范围内的黑色像素区域所占比例=黑色像素范围/显示的摄像范围；

      (5) 比较两侧黑色像素区域所占比例大小确定前进方向，如果左侧比例大于右侧，则小车左偏离，进行右转；

      (6) PC端进行图像信息处理，将处理结果传递为下位机，下位机控制小车进行相应的运动；

3.1硬件连接

接线说明：

      ① 将2510通信转接板连接到扩展板的扩展坞上面；

      ② 用3根母对母杜邦线将2510通信转接板与WiFi路由器连接起来，GND-GND、RX-RX、TX-TX；

      ③ 找到1根USB线，一端连接到2510通信转接板接口上，另一端连接到WiFi路由器USB接口上；

      ④ 将摄像头线连接到WiFi路由器接口上。

3.2示例程序

编程环境：Arduino 1.8.19

① 下位机例程：

      下位机接收上位机处理的图像信息结果控制小车相应运动，小车运动包含前进、左转、右转、停止。

参考例程代码（car.ino）如下：

/*------------------------------------------------------------------------------------版权说明：Copyright 2023 Robottime(Beijing) Technology Co., Ltd. All Rights Reserved.Distributed under MIT license.See file LICENSE for detail or copy athttps://opensource.org/licenses/MITby 机器谱 2023-02-02 https://www.robotway.com/-----------------------------------------------------------------------------------/*wift car:2019/08/19:JNleft: 9, 5;right: 10, 6;  */const String FORWARD = "F";const String BACK = "B";const String LEFT = "L";const String RIGHT = "R";const String STOP = "S";int speed_left = 41;int speed_right = 41;void setup() {Serial.begin(9600);pinMode(5, OUTPUT);pinMode(6, OUTPUT);pinMode(9, OUTPUT);pinMode(10, OUTPUT);Stop();delay(1000);}void loop() {String data = SerialRead();//if(data != ""){   if(data == FORWARD)Forward();else if(data == BACK)Back();else if(data == LEFT)Left();else if(data == RIGHT)Right();   else if(data == STOP)Stop();// }}String SerialRead(){String str;while(Serial.available()){str += char(Serial.read());}return str;}void Forward(){analogWrite(9, speed_left);analogWrite(5, 0);analogWrite(6, 0);analogWrite(10, speed_right);}void Back(){analogWrite(9, 0);analogWrite(5, speed_left);analogWrite(6, speed_right);analogWrite(10, 0);}void Left(){analogWrite(9, 0);analogWrite(5, speed_left);analogWrite(6, 0);analogWrite(10, speed_right);}void Right(){analogWrite(9, speed_left);analogWrite(5, 0);analogWrite(6, speed_right);analogWrite(10, 0);}void Stop(){analogWrite(9, speed_left);analogWrite(5, speed_left);analogWrite(6, speed_right);analogWrite(10,speed_right);}

 ② 上位机例程：

     上位机（Visual Studio 2015.net下配置OpenCV环境）进行图像信息处理。下面提供一个参考例程（MainWindow.xaml.cs），大家可尝试根据实验效果改写。

/*******************************************************************************************版权说明：Copyright 2023 Robottime(Beijing) Technology Co., Ltd. All Rights Reserved.Distributed under MIT license.See file LICENSE for detail or copy athttps://opensource.org/licenses/MITby 机器谱 2023-02-02 https://www.robotway.com/---------------------------------------------------------------------------------------using System;using System.IO;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;using System.Windows;using System.Windows.Controls;using System.Windows.Data;using System.Windows.Documents;using System.Windows.Input;using System.Windows.Media;using System.Windows.Media.Imaging;using System.Windows.Navigation;using System.Windows.Shapes;using System.Windows.Media.Animation;using System.Threading;using OpenCvSharp;using System.Drawing;using System.Drawing.Imaging;using System.Net;using System.Net.Sockets;namespace Tracking_Car{/// 
/// Tracking_Car/// 
public partial class MainWindow : System.Windows.Window{//定义视频，控制地址以及控制端口变量static string CameraIp = "http://192.168.8.1:8083/?action=stream";static string ControlIp = "192.168.8.1";static string Port = "2001";//定义上位机发送的控制命令变量//定义命令变量string CMD_FORWARD = "", CMD_TURN_LEFT = "", CMD_TURN_RIGHT = "", CMD_STOP = "";/** 指针角度对应各颜色* 25 -> 红色* 90 -> 绿色* 150 -> 蓝色*/int ANGLE_LEFT = 0;int ANGLE_GO = 0;int ANGLE_RIGHT = 0;//黑色像素在左右两侧所占比例double numOfleft = 0.0;double numOfright = 0.0;//创建视频图像实例VideoCapture capture = new VideoCapture(CameraIp); //图像大小：宽度 X 长度 = 160 X 120;Mat frame = new Mat();   //存储视频每一帧图像像素Mat result = new Mat(); //存储二值化图像static byte[] kernelValues = { 0, 1, 0, 1, 1, 1, 0, 1, 0 }; // cross (+)Mat kernel = new Mat(3, 3, MatType.CV_8UC1, kernelValues);//图像中心线坐标int x1, y1, x2, y2;//窗口面积float area;//视频显示切换变量Boolean isChange = false;//循迹开始开关变量Boolean isBegin = false;public MainWindow(){InitializeComponent();}private void Window_Loaded(object sender, RoutedEventArgs e){Assignment();}//变量赋值函数private void Assignment(){ANGLE_LEFT = 25;ANGLE_GO = 90;ANGLE_RIGHT = 150;rateLeft.Height = 10;rateRight.Height = 10;x1 = 80;y1 = 0;x2 = x1;y2 = 120;area = 160 * 120 / 2;CMD_FORWARD = "F";CMD_TURN_LEFT = "L";CMD_TURN_RIGHT = "R";CMD_STOP = "S";}/// 
/// MatToBitmap(Mat image)/// 
public static Bitmap MatToBitmap(Mat image){return OpenCvSharp.Extensions.BitmapConverter.ToBitmap(image);}/// 
/// BitmapToBitmapImage(System.Drawing.Bitmap bitmap)/// 
public static BitmapImage BitmapToBitmapImage(Bitmap bitmap){using (MemoryStream stream = new MemoryStream()){bitmap.Save(stream, ImageFormat.Png); //格式选Bmp时，不带透明度stream.Position = 0;BitmapImage result = new BitmapImage();result.BeginInit();// According to MSDN, "The default OnDemand cache option retains access to the stream until the image is needed."// Force the bitmap to load right now so we can dispose the stream.result.CacheOption = BitmapCacheOption.OnLoad;result.StreamSource = stream;result.EndInit();result.Freeze();return result;}}//颜色指示动画函数int angelCurrent = 0;private void ColorIndicate(int where){RotateTransform rt = new RotateTransform();rt.CenterX = 130;rt.CenterY = 200;this.indicatorPin.RenderTransform = rt;double timeAnimation = Math.Abs(angelCurrent - where) * 5;DoubleAnimation da = new DoubleAnimation(angelCurrent, where, new Duration(TimeSpan.FromMilliseconds(timeAnimation)));da.AccelerationRatio = 0.8;rt.BeginAnimation(RotateTransform.AngleProperty, da);switch (where){case 25:dirDisplay.Content = "左转";break;case 90:dirDisplay.Content = "前进";break;case 150:dirDisplay.Content = "右转";break;default:dirDisplay.Content = "方向指示";break;}angelCurrent = where;}//检测函数private void ColorDetect() {//将摄像头RGB图像转化为灰度图，便于后续算法处理Mat gray = frame.CvtColor(ColorConversionCodes.BGR2GRAY);//进行高斯滤波Mat binary = gray.Threshold(0, 255, ThresholdTypes.Otsu | ThresholdTypes.Binary);//闭运算，先膨胀后腐蚀，消除小型黑洞Cv2.Dilate(binary, binary, null);Cv2.Erode(binary, binary, kernel);result = binary.Clone();result.Line(new OpenCvSharp.Point(x1, y1), new OpenCvSharp.Point(x2, y2), new Scalar(255, 255, 255), 1);float rateOfleft = 0, rateOfRight = 0;var indexer = result.GetGenericIndexer();for (int i = 0; i < result.Rows; i++) {for (int j = 0; j < result.Cols; j++) {int B = indexer[i, j][0];int G = indexer[i, j][1];int R = indexer[i, j][2];if (B == 0 && G == 0 && R == 0) {if (j <= x1) {numOfleft++;}else{numOfright++;}}}}rateOfleft = (float)(numOfleft) / area * 100;rateOfRight = (float)(numOfright) / area * 100;rateLeft.Height = rateOfleft;rateRight.Height = rateOfRight;numOfleft = 0;numOfright = 0;}//命令发送函数void SendData(string data){try{IPAddress ips = IPAddress.Parse(ControlIp.ToString());//("192.168.8.1");IPEndPoint ipe = new IPEndPoint(ips, Convert.ToInt32(Port.ToString()));//把ip和端口转化为IPEndPoint实例Socket c = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);//创建一个Socketc.Connect(ipe);//连接到服务器byte[] bs = Encoding.ASCII.GetBytes(data);c.Send(bs, bs.Length, 0);//发送测试信息c.Close();}catch (Exception e){MessageBox.Show(e.Message);}}//方向指示更新及命令发送private void CommandSend() {double l = rateLeft.Height;double r = rateRight.Height;if (isBegin) {if (Math.Abs(l - r) < 20)   //两侧黑色轨迹基本相同，前进{ColorIndicate(ANGLE_GO);SendData(CMD_FORWARD);}else if ((l - r) < -50)     //左侧黑色轨迹小于右侧，右转{ColorIndicate(ANGLE_RIGHT);SendData(CMD_TURN_RIGHT);}else if ((l - r) > 50)      //右侧黑色轨迹小于左侧，左转{ColorIndicate(ANGLE_LEFT);SendData(CMD_TURN_LEFT);}}}//视频显示函数private void ThreadCapShow(){while (true){try{capture.Read(frame); // same as cvQueryFrameif (frame.Empty())break;this.Dispatcher.Invoke(new Action(delegate{if (isChange){//检测图像左右两侧黑色像素所占的比例，并显示图像ColorDetect();originImage.Source = BitmapToBitmapImage(MatToBitmap(result));CommandSend();result = null;}else{originImage.Source = BitmapToBitmapImage(MatToBitmap(frame));}}));//Cv2.WaitKey(100);//bitimg = null;}catch { }}}//加载视频private void loadBtn_Click(object sender, RoutedEventArgs e){if (originImage.Source != null) return;Thread m_thread = new Thread(ThreadCapShow);m_thread.IsBackground = true;m_thread.Start();}//切换视频显示，显示检测结果private void changeBtn_Click(object sender, RoutedEventArgs e){if (!isChange){isChange = true;changeBtn.Content = "返回";}else{isChange = false;changeBtn.Content = "切换";//指针角度归零ColorIndicate(0);rateLeft.Height = 10;rateRight.Height = 10;result = null;}}//循迹开始private void bgeinBtn_Click(object sender, RoutedEventArgs e){isBegin = true;}//循迹停止private void stopBtn_Click(object sender, RoutedEventArgs e){isBegin = false;SendData(CMD_STOP);}}}

4. 资料下载

​资料内容：
​①【R023】-视觉循迹-程序源代码
​②【R023】-视觉循迹-样机3D文件
​资料下载地址：https://www.robotway.com/h-col-113.html

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