If you were using printf
cv::Mat data(3, 3, CV_64FC1);
for (int y = 0; y < data.rows; ++y) {
for (int x = 0;x < data.cols; ++x) {
printf("%.6f ", data.at<double>(y, x));
}
}
If you were using std::cout
cv::Mat data(3, 3, CV_64FC1);
std::cout.setf(std::ios::fixed, std:: ios::floatfield);
std::cout.precision(6);
for (int y = 0; y < data.rows; ++y) {
for (int x = 0;x < data.cols; ++x) {
std::cout<<data.at<double>(y, x)<<" ";
}
}