imcircle

The file develops an "n by n" matrix containing a solid circle of ones of diameter "n" pixels.

Description

The file develops an 'n by n' matrix containing a solid circle of ones of diameter 'n' pixels, over a background of zero pixels.
 
Pixel positions are calculated on a nearest-fit basis, using trigonometry.
 
Such a circle can be an image, or part of an image, or an image mask.

A hollow circle (line circle) is also possible.

• Acknowledgements: This submission has inspired the following:; Pattern generator for MATLAB, Synthetic Microstructure Generator
• MATLAB release: MATLAB 7.2 (R2006a)

[Tom McMurray]

Thank you for saving me the trouble of coding this deceptively complex function myself.

[Michael Bach]

A bit shorter and faster:

function [c_mask]=circle(ix,iy,cx,cy,r)
[x,y]=meshgrid(-(cx-1):(ix-cx),-(cy-1):(iy-cy));
c_mask=((x.^2+y.^2)<=r^2);

Mike.

[Hamed Zahedi]

The other day I spent close to an hour trying to create a circular kernel for a convolution. This function is significantly faster.

[Deepak Bijalwan]

Thanks for saving my time.

[Aaron Mancil]

Looks Beautiful

[Pratik Kamdar]

Thnx..works great

[Siyi Deng]

Look at the comment Michael Bach left.
I was about to submit my own code before I see Mike already has posted exactly the same codes.

[Jason Zhang]

Try it