matlab - How to do people detection from bird eye view?

I'm trying to do people detection from bird eye view.

Actually, it is not a normal bird eye view because I don't have RGB images but I have disparity map, depth map as well.

In these kind of images, people are shown like lines that represent a single side of the person. I try to re-explain it: these lines represent the front or the back of the person.

I searched for papers on internet but I got no results.

Anyone have any information about that?

PS: I'm working on Matlab.

The following image shows how people looking like from a bird-eye view depth map. You don't look at the big stain. The 3 red circles contain the bird-eye view depth map of (from the left to right): a street fountain, a person and a roadsign.