如何获取keyPoint ID

Question

I'm doing a matching programm in opencv and C++ and I want to classifier my keyPoints-detected depending of the region of image they are.

ie: If I detect a keypoint in the top of the image I want to classifier this in region 1... An depending where I found the keypoints I want to classifier them.

Finally I'm going to do a new classifier vector like this:

vector classifier_vector;

and one of the two parameters that I need is the id of every detected points.

Does someone know how I can to get the keypoints id?

I'm not sure about the next but I saw that the parameter I need to get is

int _class_id

Am I right?

Thanks everybody. ;)

Answer 1

OpenCV have a KeyPoint class which have the following parameters:

pt (x,y) -> the position of the KeyPoints, size - size of the keypoint, angle - orientation of the keypoint, response - strength of the keypoint, octave - number of octave layer the keypoint is detected, class_id - the number of object the keypoint belongs to.

So basically what you need is the class_id .

keyPoint kpt;
kpt.class_id;