Question

In my application, I want to create a OpenCV Mat A (2-Dimensions) having some values and then pass it to another OpenCV function using A as input.

Currently, I’m trying:

// float data[2][5] = {{1,2,3,4,5},{7,8,9,10,11}}; 
// OR
float data[10] = {1,2,3,4,5,7,8,9,10,11};

// and then
//  A = Mat(1, 5, CV_32FC1, &data, 2);   // init from float 1D - array
// OR 
    A = Mat(2, 5, CV_32FC1, &data, 2);  

in case of 1D array, the value passing is OK. But this does not work for 2D array, which is even more a common case. How can I solve this in OpenCV??

Answer 1

Originally, I used the mnemonic from OpenCV online guides:

Mat::Mat(Size size, int type, void* data, size_t step=AUTO_STEP)

But I didn’t understand what the document meant by size_t step=AUTO_STEP. And this means that I can omit the step argument with which OpenCV will automatically choose AUTO_STEP

I’ve tried and this works:

A = Mat(2, 5, CV_32FC1, &data);

for the 2D Mat initialized from array