C++ 复制图像后，imshow中的断言失败（size.width>；0&；size.height>；0）

我有一个问题，我试图在不同的线程上显示两个图像，其中两个图像来自同一帧，但其中一个是原始帧的副本，另一个是原始帧。程序将能够完美地显示原始帧，但当带有克隆/复制图像的线程到达imshow（）时，它会崩溃，并显示错误：“在imshow中断言失败（size.width>0&&size.height>0）”

有人能帮忙吗？ 问候

这是获取相机输入的类：

CameraInput::CameraInput()
{
// Initialize capturing live feed from the camera
capture.open(0);
capture.set(CV_CAP_PROP_FRAME_WIDTH, 640);
capture.set(CV_CAP_PROP_FRAME_HEIGHT, 480);

 // Couldn't get a device? Throw an error and quit
if(!capture.isOpened())
 {
    qDebug() << "Capture could not be opened successfully.";
 }
 qDebug() << "Capure =" << QThread::currentThreadId();
}

void CameraInput::captureImage()
{
capture >> frame;

if(!frame.empty())
{
    emit capturedImage(&frame);
}
//qDebug() << "capture" << QThread::currentThreadId();
}

这是到达“发射图像（imgIn）；”时调用的函数

在下面的代码中，我们遇到了一个错误，调试行被打印出来，但是在imshow（）上我们得到了提到的错误。我们也尝试过使用copy构造函数和copyTo（），它们都会产生相同的结果

void Controll::processedImage(cv::Mat* imgIn)
{
qDebug() << "About to show thresh image...";
cv::imshow("thresh", *imgIn);
// see how much time has elapsed
time(&end);

// calculate current FPS
++counterProcessed;
sec = difftime (end, start);

fpsProcessed = counterProcessed / sec;

// will print out Inf until sec is greater than 0
printf("FPS processed stream = %.2f\n", fpsProcessed);
}

---

通过将指针和引用放在一起，解决了这个问题。我们尝试按照建议使用引用，但最终得到错误：“QObject:：connect:无法对'cv:：Mat&'类型的参数进行排队（请确保'cv:：Mat&'是使用qRegisterMetaType（）注册的）。”。我们无法注册cv:：Mat&，但cv:：Mat工作正常。

请尽量避免将指针传递到cv:：Mat，而是使用引用（破坏内部引用计数的高风险）。此外，您从视频捕获中获得的信息指向驾驶员记忆。如果要将帧传递给另一个线程（甚至在捕获循环之外使用帧），则必须克隆该帧。通过将指针和引用移到一起解决了该问题。我们尝试按照建议使用引用，但最终得到错误：“QObject:：connect:无法对'cv:：Mat&'类型的参数进行排队（请确保'cv:：Mat&'是使用qRegisterMetaType（）注册的）。”。我们无法注册cv:：Mat&，但cv:：Mat工作正常。@用户3434960您应该添加并接受自己的答案。

void Process::processImage(cv::Mat* img)
{
cv::Mat imgHSV = img->clone();
emit (processedImage(&imgHSV));
emit (readyForWork());
}

void Controll::processedImage(cv::Mat* imgIn)
{
qDebug() << "About to show thresh image...";
cv::imshow("thresh", *imgIn);
// see how much time has elapsed
time(&end);

// calculate current FPS
++counterProcessed;
sec = difftime (end, start);

fpsProcessed = counterProcessed / sec;

// will print out Inf until sec is greater than 0
printf("FPS processed stream = %.2f\n", fpsProcessed);
}

int main()
{
int c;

// Objects
CameraInput *camera = new CameraInput();
Controll *troller = new Controll();
Process *processer = new Process();
Tracking *tracker = new Tracking();
Serial_Communication *serial = new Serial_Communication("/dev/ttyUSB0");

// Threads
QThread *t1 = new QThread;
QThread *t2 = new QThread;
QThread *t3 = new QThread;
camera->moveToThread(t1);
processer->moveToThread(t2);
tracker->moveToThread(t3);
serial->moveToThread(t3);

// Connections
QObject::connect(t1, SIGNAL(started()), camera, SLOT(captureImage()));
QObject::connect(camera, SIGNAL(capturedImage(cv::Mat*)), troller, SLOT(inputImage(cv::Mat*)));
QObject::connect(t2, SIGNAL(started()), troller, SLOT(processerReady()));
QObject::connect(troller, SIGNAL(image(cv::Mat*)), processer, SLOT(processImage(cv::Mat*)));
QObject::connect(troller, SIGNAL(requestImage()), camera, SLOT(captureImage()));
QObject::connect(processer, SIGNAL(posXposY(int,int)), tracker, SLOT(position(int,int)));
QObject::connect(tracker, SIGNAL(directionAndSpeed(int,int)), serial, SLOT(sendData(int,int)));
QObject::connect(processer, SIGNAL(readyForWork()), troller, SLOT(processerReady()));
QObject::connect(processer, SIGNAL(processedImage(cv::Mat*)), troller, SLOT(processedImage(cv::Mat*)));
// Need to add finish/clean up stuff for terminating threads.

// Starting Threads
t1->start();
t2->start();
t3->start();

// wait for key to exit
while (true) {
     c = cvWaitKey(1);
    if(c!=-1)
    {
        // Add thread termination before breaking the loop.
        // If pressed, break out of the loop
        break;
    }
}
return 0;
}