Need help translating MATLAB to C

function [normim, mask, maskind] = attemptridgesegment(im, blksze, thresh)

    im = normalize(im,0,1); 

fun = @(block_struct)std2(block_struct.data) * ones(size(block_struct.data));
stddevim = blockproc(im, [blksze blksze], fun);

    mask = stddevim > thresh;
    maskind = find(mask);

    im = im - mean(im(maskind));
    normim = im/std(im(maskind));

function[n] = normalize(f, reqmean, reqvar)

    if (nargin == 1)  
  
  if ndims(f)==2                    
      if ~isa(f,'double')
            f = double(f); end
      n = f - min(f(:));
      n = n/max(n(:));
        end
    end

if (nargin ==3)
   f = double(f);  
f = f - mean(f(:));    
  f = f/std(f(:));

n = reqmean + f*sqrt(reqvar);

end

[Walter Roberson]

I don't see any good reason for the multiplication by ones() -- that just replicates the data, which isn't going to change the mean since everything is going to be replicated the same number of times. I suppose it would make a difference to the standard deviation, but my instinct is that you are worsening your std with the replication.