Find maximum value of a cv::Mat

Question

I am trying to find the maximum pixel value of a cv::Mat.

The Problem : *maxValue is always returning 0.

From this S.O. th

Answer 1

You should use the OpenCV built-in function minMaxLoc instead of std function.

Mat m;
//Initialize m
double minVal; 
double maxVal; 
Point minLoc; 
Point maxLoc;

minMaxLoc( m, &minVal, &maxVal, &minLoc, &maxLoc );

cout << "min val: " << minVal << endl;
cout << "max val: " << maxVal << endl;