color map based on area

A 3D volume is constructed from a stack of 2D masks (slices). How to color each slice based on the area of the object inside. Suppose the volume is a trunk.

[Walter Roberson]

Do you want all the pixels selected by the mask of a slice to be the same color? Or do you want to shade by value, different brightness of the color according to pixel value?

[Yazan]

I have the volume as 3D matrix (n by n by 500) and the area as a separate 1 by 500 vector.

Answer 1

[Yazan]

Thanks Walter for your comment. All pixels should have the same color based on the area of the mask at that slice. The maximum area is 12 unit square and the minimum is 4 unit square and the volume (or isosurface) was constructed from 500 slices.

Answer 2

[Walter Roberson]

https://www.mathworks.com/matlabcentral/fileexchange/22940-vol3d-v2

colorval = repmat( sum( sum( masks3d, 1), 2) ), size(masks3d, 1), size(masks3d, 2), 1 ) .* masks3d;

vol3d('CData', colorval', 'alpha', double(masks3d))