circular image plot (MATLAB)

by mikeph
Tags: circular, image, matlab, plot
mikeph is offline
Jul27-11, 04:26 AM
P: 1,199

Just came across this as an image in a book/monograph and it looks very MATLAB-esque, except I cannot figure out how to possibly create a circular image

Say I have a 500x500 matrix and want to plot it as a colour image in this way. Does anyone know how? I've been re-reading the same help files again and again with no progress.
Phys.Org News Partner Science news on
NASA's space station Robonaut finally getting legs
Free the seed: OSSI nurtures growing plants without patent barriers
Going nuts? Turkey looks to pistachios to heat new eco-city
Dr Transport
Dr Transport is offline
Jul27-11, 08:41 PM
Sci Advisor
PF Gold
P: 1,457
transform the x and y coordinates to polar coordinates and plot the new coordinates,
plot3(cos(x), sin(y));
mikeph is offline
Jul29-11, 03:39 AM
P: 1,199
Thanks for the reply, I don't fully understand how to apply it to my problem (never been strong on plot tools), my image has no coordinates, it's just a 500x500 matrix. I don't need the axis, just for the plotter to not plot anything outside a circular region. Currently I'm using pcolor with "EdgeAlpha" to zero so it looks very similar to that image I linked, but it's a square.

mikeph is offline
Nov15-11, 06:35 AM
P: 1,199

circular image plot (MATLAB)

Hi, just need to bump this, I still don't understand how to do this.
mikeph is offline
Apr26-12, 11:09 AM
P: 1,199
One more bump, I still can't find an answer, thanks

I really just need to know how to make the non-circle area white, at the moment I'm fiddling around with colour maps and manually changing the values to force it to look white, but it has side-effects.
mikeph is offline
Jun5-12, 05:42 AM
P: 1,199
Bumping to say I solved the problem.

The solution lies in the alpha data of the object.

For example you can use a ROI to make part of the object transparent, using


Where ROI = 1 the image will stay opaque and where it is 0 the image will be transparent.

Register to reply

Related Discussions
MATLAB - Image Processing - Defining Title of Plot (Pertains to Loops and Animations) Engineering, Comp Sci, & Technology Homework 0
Matlab 3D plot General Engineering 2
Matlab Image Processing Help (Image Segmentation) Math & Science Software 1
3D Plot in Matlab Programming & Computer Science 6
How to capture live video/image using Matlab without Image acq toolbox Math & Science Software 1