How to produce isosurfaces

Hi there!

My problem is simple enough, but somehow I just can't get it working. I have a 129 x 256 x 256 double 3D-image of a brain with only 1s and 0s in it (it is not a logical though, I have just segmented the white matter). Now I want to produce an isosurface of this image (I have to use the isosurface fnction, not any other contour function). What I did is simply type

 isosurface(image,1)

but the only thing I get is a 3D-coordinate system with 0:1-axes (shouldn't they be 0:129 and 0:256, if I understood the help isosurface text correctly?) but no surface. I also tried to insert my image array in place of the image array used in the help browser's Example 1, but that didn't work either. What is it that I do wrong?

Best regards,

Mikael

Answer 1

[Sven]

Hi Mikael, you're almost there. Isosurface cuts the data above the isovalue you provide. You need to change your value to, say, 0.5.

bw = zeros(50,50,50); bw(25,25,25) = 1;
D1 = bwdist(bw);
image = double(D1<15)
figure, patch(isosurface(image,1),'faceColor','b')
figure, patch(isosurface(image,0.5),'faceColor','b')

Did this sort the problem out?

[Mikael]

Hi Sven, and thank you for your answer! I will not have access to Matlab until tomorrow, but I'll try it out then and let you know how it goes.

[Mikael]

Tried it and it did work! Again, thank you so much for your help!