Re: [Vxl-maintainers] vxl/core/vil/algo/vil_corners.cxx unused variables

[Tim C. <Tim...@ma...>]

Peter Vanroose wrote:

>>--- vil_corners.cxx	4 Jul 2003 09:21:26 -0000	1.2
>>+++ vil_corners.cxx	12 Aug 2003 18:30:10 -0000	1.3
>>@@ -56,6 +56,6 @@
>>   const vcl_ptrdiff_t oj2 = grad_j.jstep();
>>   const vcl_ptrdiff_t oj3 = grad_j.istep() + grad_j.jstep();
>>-  const vcl_ptrdiff_t oj4 = -grad_j.istep();
>>-  const vcl_ptrdiff_t oj5 = grad_j.istep();
>>+  //const vcl_ptrdiff_t oj4 = -grad_j.istep(); // unused
>>+  //const vcl_ptrdiff_t oj5 = grad_j.istep();  // unused
>>   const vcl_ptrdiff_t oj6 = -grad_j.istep() - grad_j.jstep();
>>   const vcl_ptrdiff_t oj7 = -grad_j.jstep();
>>    
>>
>
>
>It looks a bit suspicious that oj4 and oj5 are unused.
>Any comments from anybody?
>  
>
The code is estimating second derivatives by passing a sobel operator 
over a pair of derivative images (assumed to have been created by a 
sobel pass of a raw image).
Due to various symmetries, d2I/dxdy == d2I/dydx, so we need only compute 
the y derivatives of the dx image.
Thus oj4,oj5 were not used.  I've now removed them.


Tim

>  
>

-- 
Tim Cootes                                  Senior Lecturer
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