How to create empty Mat in OpenCV?

Question

How to create empty Mat in OpenCV? After creation I want to use push_back method to push rows in Mat.

Something like:

Mat M(0,3,CV_32FC1);
         


        

Answer 1

just start with an empty Mat. the 1st push_back will determine type and size.

Mat big;
big.push_back(Mat(1,5,CV_64F,3.5));
big.push_back(Mat(1,5,CV_64F,9.1));
big.push_back(Mat(1,5,CV_64F,2.7));

[3.5, 3.5, 3.5, 3.5, 3.5;
 9.1, 9.1, 9.1, 9.1, 9.1;
 2.7, 2.7, 2.7, 2.7, 2.7]