无法访问平均值

Cannot Access Mean Values

本文关键字：平均值 访问      更新时间：2023-10-16

我已经计算了图像中一个区域的均值和标准差值。代码:

Mat img=imread("a.jpg");
Mat hsv1;
Mat mean, stdev;
cvtColor(img, hsv1, CV_BGR2HSV);
cv::meanStdDev(hsv1, mean, stdev, superpixel_mask);
cout << "mean: " << mean << endl << "standard deviation: " << stdev << endl;

输出为:

mean: [150.8399251737039;
  103.6980224478888;
  226.161411010155]
standard deviation: [23.98981564590477;
  46.73491195049309;
  34.41166394765997]

我想访问这些数字。我写了下面的代码:

float Mi = mean.at<float>(0,0);
cout << Mi << endl;

它给出了这个错误:

OpenCV Error: Assertion failed (dims <= 2 && data && (unsigned)i0 < (unsigned)si
ze.p[0] && (unsigned)(i1*DataType<_Tp>::channels) < (unsigned)(size.p[1]*channel
s()) && ((((sizeof(size_t)<<28)|0x8442211) >> ((DataType<_Tp>::depth) & ((1 << 3
) - 1))*4) & 15) == elemSize1()) in cv::Mat::at, file C:OpenCV249opencvbuild
includeopencv2/core/mat.hpp, line 537

这里的问题是您试图使用at<float>访问CV_64F Mat。

你可以这样解决:

double Mi = mean.at<double>(0,0);

或者声明Scalar而不是Mat:

Scalar mean, stdev;
cv::meanStdDev(hsv1, mean, stdev, superpixel_mask);
double Mi = mean[0];
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