bagoffeatures extract different types of features

Hello,

I have a problem with the function bagoffeatures implemented in matlab computer vision system toolbox.

I'm doing a study of a classification of different types of images, first of all i'm trying to use bagoffeatures with diffenrets custom extractors, i want to divide my work in 2 branches, first extract SURFpoints and extract 3 different types of descriptors, for example BRISK and FREAK.