How to visualize a 3D matrix of colormap values?

I have a 3D matrix, say 512x512x512, each element of which is a colormap value 1-8. Some of the pixels are black, and the remaining ones define a 3D object. I'd like to be able to see this object from various angles - rotate it and such. What is a simple way to 3D visualize this thing?

Answer 1

[Leepakshi]

Hi Michael,

To visualize a 3D matrix with colormap values, you can use either the volshow function for interactive visualization (for MATLAB version R2019b and later) or the isosurface and patch functions for more flexible visualization. Here are the steps for both methods:

Method 1: Using volshow

% Assuming 'data' is your 3D matrix (512x512x512) 
volshow(data, 'Colormap', jet(8), 'BackgroundColor', [0 0 0]); 

This method provides an interactive viewer for volumetric data, allowing easy rotation and exploration.

Method 2: Using isosurface and patch

figure; 
hold on; 
for i = 1:8 
    p = patch(isosurface(data, i)); 
    isocolors(data, p); 
    p.FaceColor = 'interp'; 
    p.EdgeColor = 'none'; 
end 
view(3); 
axis vis3d; 
camlight; 
lighting gouraud; 
colormap(jet(8)); 
colorbar; 
hold off; 

Note: This approach creates surfaces at specified “isovalues”, allowing visualization of different regions in the data.

Please refer to the following documentation on volshow and isosurface functions respectively:

https://www.mathworks.com/help/images/ref/volshow.html

https://www.mathworks.com/help/matlab/ref/isosurface.html

Thanks