convex hull perimeter

Hi guys, I want to determine convex hull perimeter (for convexity). I think it will be useful for shape determination.

I want to separate irregular shape and regular shape.

If not, how to distinguish irregular and regular shape??

[Image Analyst]

Can you define the difference in words first? Because I have no idea what regular and irregular mean to you. Is a circle regular? How about a square? A kite shape? A dumbbell? A star shape? An asterisk shape?

Answer 1

[Nagarajan sivathanu]

I have tried to go for centroid, perimeter but it ended as a failure

Answer 2

[Stephen]

The easiest way to discriminate between shapes is the circularity (perimeter^2/area) and eccentricity (major axis/minor axis). I think bwperim and regionprops can get you what you need. If you want to get fancier, you can calculate the bending energy of the shape. Ian T. Young wrote an easy to follow paper about bending energy of shapes in 1974. Good luck