Detecting Shaprs of circular, square, Rectangular & Triangular objects in an image.

ASSALAM-U-ALAIKUM sir

i am student of INTERNATIONAL ISLAMIC UNIVERSITY ISLAMABAD

i am doing my final year project on ''objects detection in image''

i got image from camera which have circular, rectangular, triangular, square object. i just want to know that which one are the unique properties for these shapes... e.g circle have unique property of eccentricity which we can get easily by command

REGIONPROPS ...... how can i differentiate these objects. i have to detect one object at a time in an image which contain all these objects. after detecting the required object, i want to draw a bounding box on it... i have no idea that how can i do it so plzzzzz help me out