Yes, imdilate can be applied to vectors of data (which would correspond to images that were unusually short or narrow.)
I would question whether you are going to get anything useful from applying imdilate() to a 1D "image". Perhaps the algorithm you are examining takes several consecutive windows, arranges them in a 2D array, and applies the algorithms to that? If so that would be a normal imdilate() call. imdilate() doesn't care where the data came from.
