财产暴露（15）不受设备支持

Question

#include <iostream>
#include "opencv2/highgui/highgui.hpp"
#include "opencv2/imgproc/imgproc.hpp"

using namespace cv;
using namespace std;

int B;



 int main( int argc, char** argv )
 {
    VideoCapture cap(0); //capture the video from webcam

    if ( !cap.isOpened() )  // if not success, exit program
    {
         cout << "Cannot open the web cam" << endl;
         return -1;
    }
    int Brightness = 25;
    namedWindow("Control", CV_WINDOW_AUTOSIZE); 
    cap.set(CV_CAP_PROP_EXPOSURE, 0.2);   
    createTrackbar( "Brightness", "Control", &B, 100);



    while(true){
      Mat original;
      Mat better;
      cap >> original;
      imshow("The Original Pic", original);
      waitKey(1);
    }
   return 0;
}

//我是openCV的新手，我正试图通过使用来改变曝光度 cap.set（CV_CAP_PROP_EXPOSURE，0.2）; 但“设备不支持属性暴露（15）”发生此错误，我无法修复它.. 任何帮助将不胜感激