How to generate a circle within a digital image?

Hi all,

I am working on a function H for generating a circle of radius R centered within an M-by-N digital image. The prompt suggests that I use imshow to visualize the image H for various values of R, M, and N. My issue is with generating the M-by-N digital image. I have been unable to find relevant documentation.

I am not familiar with the digital image processing capabilities of MATLAB and I am working on some exercises in anticipation for a digital image processing course. Any help would be greatly appreciated.

Answer 1

[KSSV]

I = imread('peppers.png') ; 
[nx,ny,nz] = size(I) ; 
C = [round(ny/2) round(nx/2)] ;  % center of circle 
R = 100 ;  % Radius of circle 

th = linspace(0,2*pi) ; 
xc = C(1)+R*cos(th) ; 
yc = C(2)+R*sin(th) ; 

imshow(I)
hold on
plot(xc,yc,'b')