Question

我计算了图像中某个区域的平均值和标准偏差值。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;

输出结果为：

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

我想访问这些数字。我写了那段代码：

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

它给出了错误：

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:\OpenCV249\opencv\build\
include\opencv2/core/mat.hpp, line 537

Answer 1

此处的问题是您尝试使用CV_64F访问Mat at<float>。

你可以解决这个问题：

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

或声明Scalar代替Mat：

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

无法访问平均值

1 个答案: