OpenCV：如何在 Windows 窗体应用程序中显示网络摄像头捕获？

Question

通常我们在 opencv 窗口中显示网络摄像头或视频运动：

      CvCapture* capture = cvCreateCameraCapture(0);
            cvNamedWindow( "title", CV_WINDOW_AUTOSIZE );
   cvMoveWindow("title",x,y);
   while(1) 
   {
    frame = cvQueryFrame( capture );
    if( !frame )
    {
     break;
    }
    cvShowImage( "title", frame );
    char c = cvWaitKey(33);
    if( c == 27 )
    {
     break;
    }
   }

我尝试使用 pictureBox 成功地以窗口形式显示图像：

 pictureBox1->Image = gcnew System::Drawing::Bitmap( image->width,image->height,image->widthStep,System::Drawing::Imaging::PixelFormat::Undefined, ( System::IntPtr ) image-> imageData);

但是当我尝试显示从视频中捕获的图像时，它不起作用，这里是来源：

            CvCapture* capture = cvCreateCameraCapture(0);
   while(1) 
   {
    frame = cvQueryFrame( capture );
    if( !frame )
    {
     break;
    }
    pictureBox1->Image = gcnew System::Drawing::Bitmap( frame->width,frame->height,frame->widthStep,System::Drawing::Imaging::PixelFormat::Undefined, ( System::IntPtr ) frame-> imageData);
    char c = cvWaitKey(33);
    if( c == 27 )
    {
     break;
    }
   }

有吗无论如何使用 Windows 窗体而不是 opencv Windows 来显示视频或网络摄像头？

或者我的代码有问题吗？ 感谢您的帮助.. ：）

Answer 1

一条建议：使用 VideoInput 而不是 CvCapture （CvCapture 是 highgui 库的一部分，不适用于生产用途，仅用于快速测试）。是的，VideoInput 主页看起来很奇怪，但是这个库非常值得。

以下是 VideoInput 用法的快速示例（摘自 VideoInput.h 文件）：

//create a videoInput object
videoInput VI;

//Prints out a list of available devices and returns num of devices found
int numDevices = VI.listDevices();  

int device1 = 0;  //this could be any deviceID that shows up in listDevices
int device2 = 1;  //this could be any deviceID that shows up in listDevices

//if you want to capture at a different frame rate (default is 30) 
//specify it here, you are not guaranteed to get this fps though.
//VI.setIdealFramerate(dev, 60);    

//setup the first device - there are a number of options:

VI.setupDevice(device1);                          //setup the first device with the default settings
//VI.setupDevice(device1, VI_COMPOSITE);              //or setup device with specific connection type
//VI.setupDevice(device1, 320, 240);                  //or setup device with specified video size
//VI.setupDevice(device1, 320, 240, VI_COMPOSITE);  //or setup device with video size and connection type

//VI.setFormat(device1, VI_NTSC_M);                 //if your card doesn't remember what format it should be
                                                    //call this with the appropriate format listed above
                                                    //NOTE: must be called after setupDevice!

//optionally setup a second (or third, fourth ...) device - same options as above
VI.setupDevice(device2);                          

//As requested width and height can not always be accomodated
//make sure to check the size once the device is setup

int width   = VI.getWidth(device1);
int height  = VI.getHeight(device1);
int size    = VI.getSize(device1);

unsigned char * yourBuffer1 = new unsigned char[size];
unsigned char * yourBuffer2 = new unsigned char[size];

//to get the data from the device first check if the data is new
if(VI.isFrameNew(device1)){
    VI.getPixels(device1, yourBuffer1, false, false);   //fills pixels as a BGR (for openCV) unsigned char array - no flipping
    VI.getPixels(device1, yourBuffer2, true, true);     //fills pixels as a RGB (for openGL) unsigned char array - flipping!
}

//same applies to device2 etc

//to get a settings dialog for the device
VI.showSettingsWindow(device1);


//Shut down devices properly
VI.stopDevice(device1);
VI.stopDevice(device2);

Answer 2

当您从相机捕获图像时，应该知道像素格式，它很可能是 24 位 BGR 的格式。 System::Drawing::Imaging::PixelFormat::Format24bppRgb 将是最接近的格式，但您可能会得到奇怪的颜色显示。重新排列颜色分量将解决这个问题。

实际上，这里有.net版本的opencv库：
http://code.google.com/p/opencvdotnet/
在这里：
http://www.emgu.com/wiki/index.php/Main_Page

希望有帮助！

Answer 3

我不知道你是否会喜欢这个，但是你可以使用 OpenGL 在 opencv 提供的窗口之外的其他窗口中显示视频流。 （捕获帧并将其显示在矩形上..或类似的东西..）

Answer 4

您可能要考虑的另一个选择是使用 emgu。这是带有 winforms 控件的 opencv 的 .Net 包装器。