is there a way to sort rectangle to 4 lines

i want to sort the points to 4 groups upper line lower line left and right please dont use hough tranbsform

m=zeros(200,300);
m=logical(m);
m(50,30:190)=1;
m(100,30:190)=1;
m(50:100,30)=1;
m(50:100,190)=1;
 figure,imshow(m)

[David Young]

I'm curious: what's the reason for avoiding the Hough transform?

Answer 1

[Image Analyst]

Uh yeah. Why not just do

topLine = [50,30; 50, 190];  % The x,y coordinates where each row is one endpoint.
bottomLIne = [100,30; 100, 190];
leftLine = [50,30; 100,30];
rightLine = [50,190; 100,190];

If you don't mean that , then you'd better explain specifically what you mean by "4 groups".

[Image Analyst]

Michael's "Answer" moved here since it's not an Answer to the original problem.

Not that, I mean here is the image:

[Image Analyst]

I can think of a few methods. What are you thinking of? You could use RANSAC or use traditional image processing methods (like convhull, activecontour, morphological closing, etc.) and try to extract out upper, lower, left, and right parts and then call polyfit().