How to create a signed distance transform of binary multiframe array?

I wish to perform a signed distance transform on my binary multi-frame array with dimensions, N x N x Numframes.

In case it's not clear what I want to do, I specify the problem here:

My variables are:

 imArr % my binary image array,

 Omega % the set of non zero elements of imArr, 

 Omega_c % the set of zero elements 

 boundaryOmega % the set of elements that lie 
                   on the boundary between 'Omega' and 'Omega_c'

 SDFimArr    % the  N x N x Numframes which represents the signed distance
                    transform of ImArr

then I want my distance transform to do the following:

for each x in imArr
   if x in Omega
     SDFimArr(x) =  distance(x,boundaryOmega) 
   else if x in Omega_c
     SDFimArr(x)  =  - distance(x,boundaryOmega) 
end

Please note that imArr could contain several disconnected non zero regions and 'distance' is the euclidean distance.

I'd like to avoid having to write my own code as it definitely seems that there should be efficient code out there either written in matlab or a mex file that should do this.

I would be super grateful for any pointers!