Question

I am having trouble calling EMD() in OpenCV 2.4.2 under Mac OS ML.

I have a class with an attribute Mat _signature defined like that :

Mat _signature(size,dim+1,CV_32F);
for (int i = 0; i<size; ++i){
    _signature.at<float>(i,0) = weight;
    for (int j = 1; j < dim+1; ++j){
       _signature.at<float>(i,j) = vec[i].at<float>(0,j-1); // vec[i] is a line vector containing the position in R^dim
    }
}

I then have u and v 2 instances of that class, and when I call EMD(u._signature, v._signature, CV_DIST_L2);

It fails with OpenCV Error: One of arguments' values is out of range () in icvInitEMD, file /*SOME PATH*/OpenCV-2.4.2/modules/imgproc/src/emd.cpp, line 408

I looked at the sourcecode but could not figure out what this fails. My arguments appear in correspondence to what the documentation wants. Any help will be appreciated.

Answer 1

Ok, it took me quite some time to figure it out, but among my data there was a component of one of my vector which was miscalculated, and ended up being NaN.
Of course this was buried deep into my data so that it would be completely lost in any amount of data reasonably observable via a debugger (or even cout)

The cryptic error from OpenCV did the rest in confusing me.

For people stumbling upon the same issue as me :

• Make sure your weight vectors are not zero
• Make sure none of your data is NaN