如何用C++&&OpenCV&&Qt同时调用三个摄像头

本人大二，最近在学OpenCV方面的知识，之后将不断更新有关OpenCV的内容。
话不多说，直接上代码：
1. 头文件

#pragma once
#ifndef ImageProcessing_h
#define ImageProcessing_h
#include <QtWidgets/QMainWindow>
#include<QTimer>
#include <QMessageBox>
#include "ui_imageProcessing.h"
#include <core/core.hpp>
#include <highgui/highgui.hpp>
#include<opencv2/imgproc/imgproc.hpp>
#include "opencv.hpp"
using namespace cv;
using namespace std;

class ImageProcessing : public QMainWindow
{
	Q_OBJECT

public:
	explicit ImageProcessing(QWidget *parent = Q_NULLPTR);
	~ImageProcessing();
public:
	void StartCamera();
	void CloseCamera();//关闭摄像头
private:
	VideoCapture videoCapture_1;//*定义三个VidelCapture对象来抓取摄像头图像*
	VideoCapture videoCapture_2;
	VideoCapture videoCapture_3;
	Mat frame1;//Mat类，用于保存图像
	Mat frame2;
	Mat frame3;
	VideoWriter write;//用于存储图像
	bool OPEN;
private slots:
	void OpenCamera_clicked();//打开摄像头
	void StartREC_clicked();//开始录像
private:
	Ui::ImageProcessingClass ui;
};

#endif // ImageProcessing_h

2. ImageProcessing.cpp文件

#include "ImageProcessing.h"
ImageProcessing::ImageProcessing(QWidget *parent) :
QMainWindow(parent)
{
	ui.setupUi(this);
	timer = new QTimer(this);
	OPEN = true;
	connect(ui.OpenCamera, SIGNAL(clicked()), this, SLOT(OpenCamera_clicked()));//打开相机按钮
	connect(ui.CloseCamera, SIGNAL(clicked()), this, SLOT(close()));//关闭相机按钮
	connect(ui.StartREC, SIGNAL(clicked()), this, SLOT(StartREC_clicked()));//保存视频按钮
	//connect(timer, SIGNAL(timeout()), this, SLOT(getFrame()));
}
ImageProcessing::~ImageProcessing()
{

}
void ImageProcessing::OpenCamera_clicked()
{
	// 设置彩色摄像头的拍摄属性为 分辨率1280x960，帧率25fps
videoCapture_1.set(CV_CAP_PROP_FRAME_HEIGHT, 960);
videoCapture_1.set(CV_CAP_PROP_FRAME_WIDTH, 1280);
videoCapture_2.set(CV_CAP_PROP_FRAME_HEIGHT, 960);
videoCapture_2.set(CV_CAP_PROP_FRAME_WIDTH, 1280);
videoCapture_1.set(CV_CAP_PROP_FPS, 25.0);
videoCapture_2.set(CV_CAP_PROP_FPS, 25.0);
// 设置彩色摄像头的拍摄属性为 分辨率2048x2048，帧率90fps
videoCapture_2.set(CV_CAP_PROP_FRAME_HEIGHT, 2048);
videoCapture_2.set(CV_CAP_PROP_FRAME_WIDTH, 2048);
videoCapture_3.set(CV_CAP_PROP_FPS, 90.0);
StartCamera();//启动外置摄像头,从摄像头中获取视频
}
void ImageProcessing::CloseCamera()
{
	timer->stop();
	videoCapture_1.release();
	videoCapture_2.release();
	videoCapture_3.release();
	OPEN = false;
	write.release();
	destroyWindow("摄像头1");
	destroyWindow("摄像头2");
	destroyWindow("摄像头3");

}
void ImageProcessing::StartCamera()
{
	int delay = 30;
	videoCapture_1.open(0);//注意，电脑自带摄像头为0，外加则1、2、3以此类推，这里自行配置
	videoCapture_2.open(1);
	videoCapture_3.open(2);
	if (!videoCapture_1.isOpened() || !videoCapture_2.isOpened() || !videoCapture_3.isOpened())
	{
		QMessageBox::warning(this, "Error", "Camera failed to start!");
		exit(0);
	}
	while (1)
	{
		
		videoCapture_1 >> frame1;
		namedWindow("摄像头1", WINDOW_NORMAL);
		imshow("摄像头1", frame1);

		videoCapture_2 >> frame2;
		namedWindow("摄像头2", WINDOW_NORMAL);
		imshow("摄像头2", frame2);

		videoCapture_3 >> frame3;
		namedWindow("摄像头3", WINDOW_NORMAL);
		imshow("摄像头3", frame3);
		if (waitKey(delay) == 27)			break;（按esc键退出摄像头）
		//else if(waitKey(delay)==32) 		waitKey(0);（实现按空格实时暂停功能）
		else waitKey(30);
	}
	CloseCamera();
	

}
void ImageProcessing::StartREC_clicked()//目前只做了一个摄像头的保存，其余摄像头可自行仿制
{
	videoCapture_1.open(0);
	write.open("F:\\test.avi", CV_FOURCC('M', 'J', 'P', 'G'), 10, Size(1280, 960), true);//Size最好对应上面的帧率设置。
	while (videoCapture_1.isOpened())
	{
		videoCapture_1 >> frame1;
		//write << frame1;
		//设置保存视频的格式为AVI，编码为MJPG
		write.write(frame1);
		namedWindow("摄像头1", WINDOW_NORMAL);
		imshow("摄像头1", frame1);
		if (cvWaitKey(20) == 27) break;

	}
	videoCapture_1.release();
	write.release();
	destroyWindow("摄像头1");
}

3. main文件

#include "ImageProcessing.h"
#include <QtWidgets/QApplication>

int main(int argc, char *argv[])
{
	QApplication a(argc, argv);
	ImageProcessing w;
	w.show();
	return a.exec();
}

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