Geometric shape detection in 2 D images on raspberry pi module

Project is geometric shape detection in 2 dimensional image on raspberry pi module. Image is captured from camera module interfaced with Raspberry pi and stored in memory. Reading that image we are for each blob we have to detect what is shape of that region by measuring the distance between shapes centroid and boundary. we decide what is number of vertices like triangle will have three vertices, pentagon will have 5 vertices like wise. And we have to measure what is distance of each vertice. If Equilatoral triangle is the shape 3 of vetices is of same lenght and circles radius and other basic property like area and perimeter of shape.