3D体积索引以获取任意向量Matlab

Question

I have a 3D volume and a list of x,y coordinates. I need to extract from the volume all vectors

V(x,y,:)

turned x,y to linear index but I cannot use:

V(ind,:) 

because Matlab assumes that ind is a subscript and I get an error (index exceeded...). It's OK to use V(:,ind) but that's not what I need.

Any way of doing this without repmat on the 3rd dimension and use linear index on all three dimensions? I want to avoid this, because the volume is very large.

Answer 1

You can use permute to rearrange your data matrix

 V2 = permute(V, [3 1 2]);

Then you can access the (former) z-data by V2(:,ind) , ie, V(x,y,:) would give the same result as V2(:,ind) .