（二）Qt下多线程实现多个海康工业相机内触发采集回调取流显示

**Qt下多线程实现多个海康工业相机内触发采集回调取流显示**

在实际的工业监控应用中，往往需要同时连接多个摄像头来实时监控生产过程。然而，单线程模式下，由于每次读取图像都需要等待前一帧处理完成，这会导致系统性能大幅降低，甚至可能出现卡顿或死机的情况。

因此，我们需要使用多线程技术来实现同时连接多个摄像头的实时监控功能。下面是基于Qt的多线程实现多个海康工业相机内触发采集回调取流显示的详细步骤和代码示例：

### **1. 安装必要库**

首先，我们需要安装必要的库，包括Qt、OpenCV和Hikvision SDK。

bashsudo apt-get install libqt5-dev libopencv-dev libhikvision-sdk-dev

cpp// camera_thread.h#ifndef CAMERA_THREAD_H#define CAMERA_THREAD_H#include 
#include 

class CameraThread : public QThread {
 Q_OBJECTpublic:
 explicit CameraThread(QObject *parent = nullptr);
 ~CameraThread();

signals:
 void imageReady(QImage image);

protected:
 void run() override;

private:
 int cameraId;
};

#endif // CAMERA_THREAD_H

cpp// camera_thread.cpp#include "camera_thread.h"

CameraThread::CameraThread(QObject *parent) : QThread(parent), cameraId(0) {}

CameraThread::~CameraThread() {}

void CameraThread::run() {
 //读取图像并回调给主线程 QImage image = readImage(cameraId);
 emit imageReady(image);
}

QImage CameraThread::readImage(int cameraId) {
 // 实现读取图像的逻辑}

cpp// main_thread.h#ifndef MAIN_THREAD_H#define MAIN_THREAD_H#include 
#include 

class MainThread : public QThread {
 Q_OBJECTpublic:
 explicit MainThread(QObject *parent = nullptr);
 ~MainThread();

signals:
 void imageUpdated(QImage image);

protected:
 void run() override;

private:
 CameraThread *cameraThread;
};

#endif // MAIN_THREAD_H

cpp// main_thread.cpp#include "main_thread.h"

MainThread::MainThread(QObject *parent) : QThread(parent), cameraThread(nullptr) {}

MainThread::~MainThread() {}

void MainThread::run() {
 // 接收回调信号并显示图像 while (true) {
 QImage image = cameraThread->imageReady();
 emit imageUpdated(image);
 }
}

cpp// main.cpp#include "main_thread.h"
#include "camera_thread.h"

int main() {
 // 实现多个摄像头的连接 CameraThread *cameraThread1 = new CameraThread();
 CameraThread *cameraThread2 = new CameraThread();

 MainThread *mainThread = new MainThread();
 mainThread->cameraThread = cameraThread1;
 mainThread->start();

 // 将每个摄像头对应的图像读取线程添加到主线程中 QThread *thread1 = new QThread();
 thread1->setObjectName("Camera Thread1");
 thread1->start(cameraThread1);

 QThread *thread2 = new QThread();
 thread2->setObjectName("Camera Thread2");
 thread2->start(cameraThread2);

 return QApplication::exec();
}

cpp// main.cpp (续)
#include "main_thread.h"

void MainThread::run() {
 // 接收回调信号并显示图像 while (true) {
 QImage image = cameraThread->imageReady();
 emit imageUpdated(image);
 }
}

// display_image.h#ifndef DISPLAY_IMAGE_H#define DISPLAY_IMAGE_H#include 
#include 

class DisplayImage : public QLabel {
 Q_OBJECTpublic:
 explicit DisplayImage(QWidget *parent = nullptr);

signals:
 void imageUpdated(QImage image);

protected:
 void paintEvent(QPaintEvent *) override;

private:
 QImage image;
};

#endif // DISPLAY_IMAGE_H

cpp// display_image.cpp#include "display_image.h"

DisplayImage::DisplayImage(QWidget *parent) : QLabel(parent), image() {}

void DisplayImage::paintEvent(QPaintEvent *) {
 QPainter painter(this);
 painter.drawImage(0,0, image);
}

void DisplayImage::imageUpdated(QImage image) {
 this->image = image;
 update();
}

cpp// main.cpp (续)
#include "display_image.h"

int main() {
 // 实现多个摄像头的连接 CameraThread *cameraThread1 = new CameraThread();
 CameraThread *cameraThread2 = new CameraThread();

 MainThread *mainThread = new MainThread();
 mainThread->cameraThread = cameraThread1;
 mainThread->start();

 // 将每个摄像头对应的图像读取线程添加到主线程中 QThread *thread1 = new QThread();
 thread1->setObjectName("Camera Thread1");
 thread1->start(cameraThread1);

 QThread *thread2 = new QThread();
 thread2->setObjectName("Camera Thread2");
 thread2->start(cameraThread2);

 // 显示图像 DisplayImage *displayImage = new DisplayImage();
 connect(mainThread, &MainThread::imageUpdated, displayImage, &DisplayImage::imageUpdated);
 displayImage->show();

 return QApplication::exec();
}