C++ OpenCV：如何在 Windows 窗体应用程序中显示网络摄像头捕获？

OpenCV : How to display webcam capture in windows form application?

提问by sneixum

generally we display webcam or video motion in opencv windows with :

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;
    }
   }

i tried to use pictureBox that is successful to display image in windows form with this :

我尝试使用成功以 Windows 形式显示图像的图片框：

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

but when im trying to display captured image from video it wont works, here is the source :

但是当我尝试从视频中显示捕获的图像时，它不起作用，这是来源：

            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;
    }
   }

is there anyway to use windows form instead opencv windows to show video or webcam?

无论如何使用windows形式而不是opencv windows来显示视频或网络摄像头？

or is there something wrong with my code? thanks for your help.. :)

还是我的代码有问题？感谢您的帮助.. ：）

回答by Pascal T.

Piece of advice : use VideoInputinstead of CvCapture (CvCapture is a part of highgui a library that is not intended for production use, but just for quick testing). Yes the VideoInput homepage looks strange, but the library is quite worthwhile.

一条建议：使用VideoInput而不是 CvCapture（CvCapture 是 highgui 库的一部分，该库不用于生产用途，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。

Here is a quick sample for the usage of VideoInput (extracted from the VideoInput.h file):

以下是 VideoInput 使用的快速示例（从 VideoInput.h 文件中提取）：

//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);

回答by james

The pixel format should be known when you capture images from a camera, it's very likely the format of 24-bit BGR. System::Drawing::Imaging::PixelFormat::Format24bppRgbwill be the closest format but you might get weird color display. A re-arrange of the color component will solve this problem.

当您从相机捕获图像时，应该知道像素格式，很可能是 24 位 BGR 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。

Actually, there are .net version opencv library available here: http://code.google.com/p/opencvdotnet/and here: http://www.emgu.com/wiki/index.php/Main_Page

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

Hope it helps!

希望能帮助到你！

回答by elephantintheroom

I don't know if you will like this, but you could use OpenGL to show the video stream in other windows than the ones provided with opencv. (Capture the frame and display it on a rectangle.. or something like that..)

我不知道你是否会喜欢这个，但你可以使用 OpenGL 在其他窗口中显示视频流，而不是 opencv 提供的窗口。（捕获框架并将其显示在矩形上.. 或类似的东西..）

回答by sav

Another option you might want to consider is using emgu. This is a .Net wrapper for opencv with winforms controlls.

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。