Image aggregation

% AggregateIma resize an image to a smaller one

% AggregateIma resample (or resize) an image to a smaller one using 6 possible function
% (Fct).
% in:
% - ImaIN: image N dimension
% - n: factor for aggregation.
% - Fct: type of aggregation (1=mean (default); 2=mode; 3=std; 4=min;
% 5=max; 6=median)
% out = ImaOUT: aggregated image.
% ex: if ImaIN is a 100 by 100 image and n=4, ImaOUT will be a 25*25 image
%
% Notice that it works with N dimension image and an extra dimension is
% temporally added to compute the aggregation. there is no pixel by pixel
% (time consuming) computation.

% Author: Martin Claverie, University of Maryland
% date: November 2012