《学习OpenCV》练习题第二章第五题

  1 #include <highgui.h>
  2 #include <cv.h>
  3 
  4 #pragma comment (lib,"opencv_calib3d231d.lib")
  5 #pragma comment (lib,"opencv_contrib231d.lib")
  6 #pragma comment (lib,"opencv_core231d.lib")
  7 #pragma comment (lib,"opencv_features2d231d.lib")
  8 #pragma comment (lib,"opencv_flann231d.lib")
  9 #pragma comment (lib,"opencv_gpu231d.lib")
 10 #pragma comment (lib,"opencv_haartraining_engined.lib")
 11 #pragma comment (lib,"opencv_highgui231d.lib")
 12 #pragma comment (lib,"opencv_imgproc231d.lib")
 13 #pragma comment (lib,"opencv_legacy231d.lib")
 14 #pragma comment (lib,"opencv_ml231d.lib")
 15 #pragma comment (lib,"opencv_objdetect231d.lib")
 16 #pragma comment (lib,"opencv_ts231d.lib")
 17 #pragma comment (lib,"opencv_video231d.lib")
 18 
 19 /*
 20  *《学习OpenCV》第二章第五题
 21  * 从摄像机读入视频数据，加入滚动条，可以动态调节缩放比例。
 22  * 完成时间：23:05 3/31 星期日 2013
 23  */
 24 
 25 int g_slider_position = 0;   // 记录滚动条位置的全局变量
 26 int g_scaling = 2;    // 记录缩放比例的全局变量
 27 
 28 void onTrackbarSlide(int pos)
 29 {
 30     // 改变缩放比例
 31     g_scaling = pos + 2;
 32 }
 33 
 34 IplImage * doPryDown(IplImage * in, int filter = IPL_GAUSSIAN_5x5)
 35 {
 36     IplImage * out; 
 37     
 38     CvSize newSize = cvSize( (int)( in->width / 2 ),(int) (in->height / 2 ) );
 39     out = cvCreateImage( newSize, in->depth, in->nChannels);
 40     cvPyrDown( in, out );
 41     return out;
 42 }
 43 
 44 int main()
 45 {
 46     CvCapture* capture;
 47 
 48     // 选择第一个摄像头
 49     capture = cvCreateCameraCapture(0);
 50     if(capture == NULL)
 51     {
 52         printf("Camera error.\texit.\n");
 53         exit(-1);
 54     }
 55 
 56     // 创建窗口
 57     cvNamedWindow("Camera", 0);
 58     
 59     IplImage *frame = cvQueryFrame(capture);
 60     IplImage *frame_pyrdown;
 61     
 62     if (!frame)
 63     {
 64         return 0;
 65     }
 66     // 创建滑动条
 67     cvCreateTrackbar( "scaling", "Camera", &g_slider_position, 
 68         6, onTrackbarSlide );
 69 
 70     while(1)
 71     {     
 72         // 读数据
 73         frame = cvQueryFrame(capture);
 74                 
 75         if (!frame)
 76         {
 77             break;
 78         }
 79         // 缩放变换(2-8之间)
 80         frame_pyrdown = doPryDown( frame, 7);
 81         for(int i = 2; i < g_scaling; i++)
 82         {
 83             frame_pyrdown = doPryDown( frame_pyrdown, 7);
 84         }
 85     
 86         printf("目前缩放比例: %d\t(%d, %d)\n", g_scaling,
 87             frame_pyrdown->width, frame_pyrdown->height);
 88 
 89         // 显示出来
 90         cvShowImage("Camera", frame_pyrdown);
 91 
 92         char c = cvWaitKey(50);
 93         if (c == 27)
 94         {
 95             break;
 96         }
 97     }
 98 
 99     // 释放资源
100     cvReleaseCapture(&capture);
101     cvReleaseImage( &frame);
102     cvReleaseImage( &frame_pyrdown);
103     cvDestroyWindow("Camera");
104 
105     return 0;
106 }
运行结果：
缩放2比例为2：
缩放比例为4：
缩放比例为5：
存在的问题：图像变模糊了，该怎么自适应地改变预览窗口呢？