Question

我在this页面上看到了一段代码。这是一个整洁的函数，它接受char*和多个IplImage*参数作为输入，然后在一个窗口中显示所有图像。

我想对一张图片和一段视频做同样的事情。因此，除了更改主要功能以初始化网络摄像头输入，以及修改对上述功能的调用之外，我还需要改变什么？

我的主要功能是：

int main() {

    IplImage *img1 = cvLoadImage("image1.png");

   CvCapture* capture = cvCaptureFromCAM(0);
   if ( !capture ) {
     fprintf( stderr, "ERROR: capture is NULL \n" );
     getchar();
     return -1;
   }
   // Create a window in which the captured images will be presented
   cvNamedWindow( "mywindow", CV_WINDOW_AUTOSIZE );
   // Show the image captured from the camera in the window and repeat
   while ( 1 ) {
     // Get one frame
     IplImage* frame = cvQueryFrame( capture );
     if ( !frame ) {
       fprintf( stderr, "ERROR: frame is null...\n" );
       getchar();
       break;
     }
     //cvShowImage( "mywindow", frame );
     cvShowManyImages("Image", 2, img1, frame);
     // Do not release the frame!
     //If ESC key pressed, Key=0x10001B under OpenCV 0.9.7(linux version),
     //remove higher bits using AND operator
     if ( (cvWaitKey(10) & 255) == 27 ) break;
   }
   // Release the capture device housekeeping
   cvReleaseCapture( &capture );
   cvDestroyWindow( "mywindow" );

    return 0;
}

这个问题是，它只显示视频的第一帧。我需要继续按esc以获得下一帧。

Answer 1

这可以根据需要使用：

void cvShowManyImages(char* title, int nArgs, ...) {

    // img - Used for getting the arguments 
    IplImage *img;

    // DispImage - the image in which input images are to be copied
    IplImage *DispImage;

    int size;
    int i;
    int m, n;
    int x, y;

    // w - Maximum number of images in a row 
    // h - Maximum number of images in a column 
    int w, h;

    // scale - How much we have to resize the image
    float scale;
    int max;

    // If the number of arguments is lesser than 0 or greater than 12
    // return without displaying 
    if(nArgs <= 0) {
        printf("Number of arguments too small....\n");
        return;
    }
    else if(nArgs > 12) {
        printf("Number of arguments too large....\n");
        return;
    }
    // Determine the size of the image, 
    // and the number of rows/cols 
    // from number of arguments 
    else if (nArgs == 1) {
        w = h = 1;
        size = 300;
    }
    else if (nArgs == 2) {
        w = 2; h = 1;
        size = 300;
    }
    else if (nArgs == 3 || nArgs == 4) {
        w = 2; h = 2;
        size = 300;
    }
    else if (nArgs == 5 || nArgs == 6) {
        w = 3; h = 2;
        size = 200;
    }
    else if (nArgs == 7 || nArgs == 8) {
        w = 4; h = 2;
        size = 200;
    }
    else {
        w = 4; h = 3;
        size = 150;
    }

    // Create a new 3 channel image
    DispImage = cvCreateImage( cvSize(100 + size*w, 60 + size*h), 8, 3 );
    cvZero(DispImage);
    // Used to get the arguments passed
    va_list args;
    va_start(args, nArgs);

    // Loop for nArgs number of arguments
    for (i = 0, m = 20, n = 20; i < nArgs; i++, m += (20 + size)) {

        // Get the Pointer to the IplImage
        img = va_arg(args, IplImage*);

        // Check whether it is NULL or not
        // If it is NULL, release the image, and return
        if(img == 0) {
            printf("Invalid arguments");
            cvReleaseImage(&DispImage);
            return;
        }

        // Find the width and height of the image
        x = img->width;
        y = img->height;

        // Find whether height or width is greater in order to resize the image
        max = (x > y)? x: y;

        // Find the scaling factor to resize the image
        scale = (float) ( (float) max / size );

        // Used to Align the images
        if( i % w == 0 && m!= 20) {
            m = 20;
            n+= 20 + size;
        }

        // Set the image ROI to display the current image
        cvSetImageROI(DispImage, cvRect(m, n, (int)( x/scale ), (int)( y/scale )));

        // Resize the input image and copy the it to the Single Big Image
        cvResize(img, DispImage);

        // Reset the ROI in order to display the next image
        cvResetImageROI(DispImage);
    }

    // Create a new window, and show the Single Big Image
    //    cvNamedWindow( title, 1 );
    cvShowImage( title, DispImage);

    //    cvWaitKey(20);


    // End the number of arguments
    va_end(args);

    // Release the Image Memory
    cvReleaseImage(&DispImage);
}
int main() {

    IplImage *img1 = cvLoadImage("d:\\ImagesForTest\\cat.bmp");

    CvCapture* capture = cvCaptureFromCAM(0);
    if ( !capture ) {
        fprintf( stderr, "ERROR: capture is NULL \n" );
        getchar();
        return -1;
    }
    // Create a window in which the captured images will be presented
    cvNamedWindow( "mywindow", CV_WINDOW_AUTOSIZE );
    // Show the image captured from the camera in the window and repeat
    while ( 1 ) {
        // Get one frame
        IplImage* frame = cvQueryFrame( capture );
        if ( !frame ) {
            fprintf( stderr, "ERROR: frame is null...\n" );
            getchar();
            break;
        }
        //cvShowImage( "mywindow", frame );
        cvShowManyImages("Image", 2, img1, frame);
        // Do not release the frame!
        //If ESC key pressed, Key=0x10001B under OpenCV 0.9.7(linux version),
        //remove higher bits using AND operator
        if ( (cvWaitKey(10) & 255) == 27 ) break;
    }
    // Release the capture device housekeeping
    cvReleaseCapture( &capture );
    cvDestroyAllWindows();

    return 0;
}

如何使用OpenCV在一个窗口中显示一个图像和一个视频

1 个答案: