Straight line through center of polygon

Hi,

I have polygon ROI and I need to draw a straight line through the center of the polygon and through the middle of superior (S1 & S2) / inferior (I1 & I2) points of the ROI. In my case, the ROI polygons are of various sizes and shapes. I am attaching a picture of a sample ROI of my work. Please help me regarding this.

Answer 1

[KSSV]

If you have the vertices of the polygon, you can fit a striaght line and draw it.

Example:

P = [0 0 ; 1 0 ; 1 1 ; 0 1] ;  % vertices of the polygon 
p = polyfit(P(:,1),P(:,2),1) ; % fit a striaght line 

xi = P(:,1) ; 
yi = polyval(p,xi) ;

patch(P(:,1),P(:,2),'r')
hold on
plot(xi,yi,'b')

[Sunetra Banerjee]

Hi KSVV,

Thanks for your answer. I don't have the exact vertices of the polygon. How to get that?

[Sunetra Banerjee]

If I be more specific, I need the vertices of the polygon.