Qt5和opencv常用函数

void MainWindow::nextFrame()
{
    camera>>frame;//已在头文件里声明camera和frame
    if(!frame.empty())
    {
        image=Mat2QImage(frame);
        ui->label->setPixmap(QPixmap::fromImage(image));
    }
}

void MainWindow::on_pushButton_2_clicked()
{
    if (capture.isOpened())
           capture.release();     //decide if capture is already opened; if so,close it
       capture.open(0);           //open the default camera
       if (capture.isOpened())
       {
           rate= capture.get(CV_CAP_PROP_FPS);
           capture >> frame;
           if (!frame.empty())
           {

               image = Mat2QImage(frame);
               ui->label->setPixmap(QPixmap::fromImage(image));
               QTimer *timer = new QTimer(this);
               timer->setInterval(1000/rate);   //set timer match with FPS
               connect(timer, SIGNAL(timeout()), this, SLOT(nextFrame()));
               timer->start();
           }
       }
}