找到cv :: Mat的最大值

Question

我试图找到a的最大像素值cv::Mat.

问题:*maxValue总是回归0.

从这个SO线程,我理解' max_element返回迭代器,而不是值.这就是我使用*maxValue'的原因

cv::Mat imageMatrix;

double  sigmaX = 0.0;
int ddepth = CV_16S; //  ddepth – The desired depth of the destination image


cv::GaussianBlur( [self cvMatFromUIImage:imageToProcess], imageMatrix, cv::Size(3,3), sigmaX);

cv::Laplacian(imageMatrix, imageMatrix, ddepth, 1);

std::max_element(imageMatrix.begin(),imageMatrix.end());

std::cout << "The maximum value is : " << *maxValue << std::endl;

注意:如果min_element替换代替max_element,则minValue代替maxValue,*minValue将始终返回0.

Answer 1

您应该使用OpenCV内置函数minMaxLoc而不是std函数.

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;