How can I implement a fisheye lens effect (barrel transformation) in MATLAB?

Question

How can one implement the fisheye lens effect illustrated in that image:

One can us

Answer 1

Just for the record:

This effect is a type of radial distortion called "barrel distortion".

For more information please see:

http: //en.wikipedia.org/wiki/Distortion_(optics)

Here is a different method to apply an effect similar to barrel distortion using texture mapping (adapted from MATLAB Documentation):

[I,map] = imread('logo.gif');
[h,w] = size(I);

sphere; 

hS = findobj('Type','surface');

hemisphere = [ones(h,w),I,ones(h,w)];

set(hS,'CData',flipud(hemisphere),...
    'FaceColor','texturemap',...
    'EdgeColor','none')

colormap(map)
colordef black
axis equal
grid off
set(gca,'xtick',[],'ztick',[],'ytick',[],'box','on')
view([90 0])

This will give you the circular frame you are looking for but the aliasing artifacts might be too much to deal with.