find intersection of boundary points

I have set of boundary points which has been acquired through bwboundaris function( it is almost square). Now how to find 4 vertices of the shape.

Answer 1

[Image Analyst]

Use convhull().

[Anil Patel]

but how to get vertex coordinates thanks

[Image Analyst]

OK, admit it, you never even looked at the documentation, did you? Well if you do, you'll see this example:

xx = -1:.05:1;
yy = abs(sqrt(xx));
[x,y] = pol2cart(xx,yy);
k = convhull(x,y);
plot(x(k),y(k),'r-',x,y,'b*')

And of course x(k) and y(k) are the vertices. If you want coordinates that are not the convex hull, then see my shape recognition demo.

[Anil Patel]

I have already got vertices from boundaries command but now how to get corner location ? youe demo doesnt work it say something else found as its not regular square.

[Image Analyst]

If you have more than 4 convex hull points, then you'll have to figure out which of those are the corner points. Use my demo where I computed the distance away from the centroid and then found the peaks.