Question

I have a very basic query about storing vectors in OpenCV, but since I’ve always worked in MATLAB, I am finding it really difficult to perform the same vector operations in C++.

So here’s my problem, I have computed optical flow using the basic cvGoodFeaturesToTrack() and cvCalcOpticalFlowPyrLK() functions and find the flow lines’ end points and show them on the image as lines of optical flow.

However, I want to store these flow line end points in a vector and then save it as a text file which I can then send to MATLAB for reading.

I really don’t know how I can create these vectors that store these points and save them on a text file.

Can anyone help?

Thanks,

Yash

Answer 1

Based on the OP’s comments on the question i think this is a good way to do it:

std::ofstream matlabFile;
matlabFile.open("pointsOutput.m");
matlabFile << "Corners = [ ...\n";
for (int i = 0; i < MAX_CORNERS; ++i) {
    matlabFile << corners2[i].x << " " << corners2[i].y << "; ...\n";
}
matlabFile << "];";
matlabFile.close();

This code should give you the following file at the local directory:

pointsOutput.m:

Corners = [ ...
1 2; ...
3 4; ...
];

which in matlab will give you the fiollowing matrix:

Corners = 
    1 2
    3 4

Assuming you have two points in that list with x and y = 1 and 2, 3 and 4.

Hope this helps.