About rotation images

[mrgloom]

Looks like here
https://github.com/Jack-CV/FaceKit/blob/master/PCN/PCN.cpp#L594
you just vertically flip image obtaining img180 which is not the same as clockwise rotation +180 degrees as mentioned in figure 5 in paper, is it desired behaviour, what logic behind it?

i.e. seems correct way should look like
https://stackoverflow.com/a/5912847/1179925