% OUT = IM2COL(IM) is a matrix (NxP) where each row represents a single % of the image IM (HxWxP). The pixels are in image column order (ie. column % 1, column 2 etc) and there are N=WxH rows. % OUT = ...

% S = IDECIMATE(IM, M) is a decimated version of the image IM whose % size is reduced by M (an integer) in both dimensions. The image is smoothed % with a Gaussian kernel with standard deviation M/2 ...