Image flip around arbitrary axis

I have a 128x128 binary mask. I would like to flip the image with respective to an arbitrary axis, similar to what 'flipup' and 'fliplr' do but with a user defined axis. Is there a quick and easy way to get this done? Thanks for reading.

Answer 1

[Matt J]

Using AxelRot ( Download ) you could do the flip as follows given the direction vector u and a point x0 on the line in (i,j) pixel coordinates

[i,j]=find(yourMask);

ij0=[i,j].'; 

      ij0(3,end)=0;  %Embed in 3D
      u(3)=0;
      x0(3)=0;  

 ij=round(AxelRot( ij0, 180,u,x0 )).';

 newMask=accumarray(ij(:,1:2),true,size(yourMask));

The above does nearest neighbor interpolation whenever the flipping places pixels at non-integer locations.