LoadIm.m

function [ im, ii_im ] = LoadIm( im_fname, varargin )
%LoadIm Load image
%   Input: 
    % 1) Filename of an image
    % 2) if varargin{1} is set to 1, sanity check is enabled
%   Output: Two arrays
    % 1) Normalized version of the pixel data of the image
    % 2) It's integral image
    
    % Read in image
    im = imread(im_fname);
    im = double(im);
    [x, y] = size(im);
    
    % Image normalization orig
    im = im(:);
    mu = mean(im);
    sigma = std(im);
    if sigma == 0
       sigma = 1; 
    end
    im = (im - mu) / sigma;

    dflag = 0;
    if nargin > 1
       dflag = 1;
    end
    % Sanity check
    if dflag == 1
        if (round(mean(im)) == 0) && (round(std(im)) == 1)
           disp('[Success] LoadIm (Sanity check): im is normalized');
        else
            msg = '[Fail] LoadIm (Sanity check): im is not normalized';
            error(msg);
        end   
    end
    
    % Reshape back to original dimensions
    im = reshape(im, [x, y]);
    
    % Compute the integral image
    ii_im = cumsum(cumsum(im, 1), 2);
% 
%    im = double(imread(im_fname));
%     mu = mean(im(:));
%     sd = std(im(:));
%     if sd == 0
%        sd = 1; 
%     end
%     n_im = (im - mu) / sd;
%     
%     ii_im = cumsum(cumsum(n_im, 2));
%     im = n_im;
end