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  • Committer: Suren A. Chilingaryan
  • Date: 2009-01-15 13:50:29 UTC
  • Revision ID: csa@dside.dyndns.org-20090115135029-wleapicg9a4593tp
Initial import

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dic_local_sum.m
 
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%-------------------------------
 
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% Function  local_sum
 
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%
 
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function local_sum_A = dic_local_sum(A,m,n)
 
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% We thank Eli Horn for providing this code, used with his permission,
 
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% to speed up the calculation of local sums. The algorithm depends on
 
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% precomputing running sums as described in "Fast Normalized
 
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% Cross-Correlation", by J. P. Lewis, Industrial Light & Magic.
 
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% http://www.idiom.com/~zilla/Papers/nvisionInterface/nip.html
 
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[mA,nA]=size(A);
 
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B = [zeros(m,nA+2*n-1);
 
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     zeros(mA,n) A zeros(mA,n-1);
 
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     zeros(m-1,nA+2*n-1)];
 
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s = cumsum(B,1);
 
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c = s(1+m:end,:)-s(1:end-m,:);
 
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s = cumsum(c,2);
 
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local_sum_A = s(:,1+n:end)-s(:,1:end-n);