OpenCV图像像素值统计

QString appPath = QCoreApplication::applicationDirPath();
  imagePath = appPath + "/A.jpg";
  img = cv::imread(imagePath.toStdString());
  if (img.empty())
    return;
  double minv, maxv;
  Point minLoc, maxLoc;
  std::vector<Mat> mv;
  split(img, mv);
  for (int i = 0; i < mv.size(); i++)
  {
    //图像必须单通道
    minMaxLoc(mv[i], &minv, &maxv, &minLoc, &maxLoc, cv::Mat());
    std::cout << "channel" << i << "min value" << minv << "max value" << maxv<<std::endl ;
  }
  Mat mean, stddev;
  //计算均值方差
  meanStdDev(img,mean,stddev);
  std::cout << "mean" << mean << "stddev" << stddev << std::endl;