OpenCV 2.1: where is ostream operator<< for cv::Mat?

Question

Following this question, I am attempting to print out the contents of a cv::Mat to standard output:

#include <iostream>
#include <opencv/cv.h>
#include <opencv/cv.hpp>
#include <opencv/cxcore.h>
#include <opencv/cxcore.hpp>

int main() {

  cv::Mat m = cv::Mat::ones(10, 10, CV_32S);
  std::cout << m << "\n";

}

This results in the error

error: no match for ‘operator<<’ in ‘std::cout << m’

I am using gcc 4.6.1 on Ubuntu 11.10, and installed opencv, excluding the examples, following these instructions. My question is, is the operator available in 2.1 and if so, how do I get it?

If the operator is not defined, you might need to upgrade to 2.2 or above. — , Apr 04 '12 at 14:30

score 5 · Accepted Answer · answered Apr 04 '12 at 15:10

5

Update to OpenCV 2.2 (or higher) and #include <opencv2/opencv.hpp>

It's defined at modules/core/include/opencv2/core/operations.hpp

answered Apr 04 '12 at 15:10

karlphillip

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Thanks. After a rather painful installation of opencv 2.3.1 it works. The only header needed for the example is . – juanchopanza Apr 04 '12 at 16:58

score 2 · Answer 2 · answered Apr 04 '12 at 16:06

2

If the operator is not defined, you might need to upgrade to 2.2 or above. Documented Here Its where you can find the overloaded operators code.

answered Apr 04 '12 at 16:06

OpenCV 2.1: where is ostream operator<< for cv::Mat?

2 Answers2

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