How to get to shoulders localization on image photo? I have a project on my university. I have to localize from video where are shoulders of person in movie.

Do have any advise how to get to this? 

I thought about corner detection or some kind of shape detection. But I'm still not sure what next. We can treat video like image sequence (I wrote this, but I think is obvious)
Are there just shoulders in the video, or is there a head attached to them?

If it is the latter, then you can use vision.CascadeObjectDetector from the Computer Vision System Toolbox for Matlab.  It has the "upper body" mode, which effectively detects head and shoulders.