OpenCV. FisherFace "model->predict"

First time question here, tx in advance.

I am trying to use code from opencv tutorial that use the fisherface algorithim.

I am able to create the fisherface model and train it,detect faces but fail on the recognition part model->predict.

I am also pretty new to C++ and trying to debug this problem myself but I guess I still need help here.

Jumping in at line model->predict(face_im)

I get to the following line of code in operations.hpp and fail immediately without any description of the error.

template<typename _Tp> inline _Tp* Ptr<_Tp>::operator -> () { return obj; }

executing this line jumps back out to the main and breaks with error Access violation reading location 0x00000019.

agh, I hope this is not to vague but how can i analyze my problem here?

Again tx in advance and if more info is needed ..sure thing

Et

I've come to a conclusion; it was a scoping problem. By moving the declaration out of main, I was able to get it to work fine.

I guess it was very vague. It's still a bit unclear to me, but I suppose I need to brush up on my C++.