小型双轮差速底盘视觉循迹功能的实现

机器谱 · 发表于 2023-3-6 09:42:12

本帖最后由机器谱于 2023-3-6 09:42 编辑

1. 任务描述

在机器人小车上搭载摄像头，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：

主控板	Basra（兼容Arduino Uno）
扩展板	Bigfish2.1
电池	7.4V锂电池
通信	2510通信转接板
通信	WiFi路由器
其它	摄像头x1、计算机x1

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 at
https://opensource.org/licenses/MIT
by 机器谱 2023-02-02 https://www.robotway.com/
-----------------------------------------------------------------------------------
/*
wift car:
2019/08/19:
JN
left: 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);
}

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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。

/*******************************************************************************************
Distributed under MIT license.See file LICENSE for detail or copy at
https://opensource.org/licenses/MIT
by 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
{
/// <summary>
/// Tracking_Car
/// </summary>
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";
}
/// <summary>
/// MatToBitmap(Mat image)
/// </summary>
public static Bitmap MatToBitmap(Mat image)
{
return OpenCvSharp.Extensions.BitmapConverter.ToBitmap(image);
}
/// <summary>
/// BitmapToBitmapImage(System.Drawing.Bitmap bitmap)
/// </summary>
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<Vec3b>();
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Socket
c.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 cvQueryFrame
if (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);
}
}
}

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4. 资料下载

资料内容：
① 视觉循迹-程序源代码
② 视觉循迹-样机3D文件

资料下载地址：https://www.robotway.com/h-col-113.html

想了解更多机器人开源项目资料请关注机器谱网站 https://www.robotway.com

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小型双轮差速底盘视觉循迹功能的实现

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