[Insight-users] Round-off Errors

[Invisible Human]

Hi,
 
In trying to get sagittal slices from an RGB volume i
am getting some data corruption which i believe is
because of round-off errors.
 
Simply put, my code does this:
 

rot[0] = 0.0; rot[1] = 1.0; rot[2] = 0.0;
transform->Rotate3D(rot,90*atan(1.0)/45.0); 

rot[1]= 0 ; rot[0] = 1; rot[2]= 0;
transform->Rotate3D(rot,90*atan(1.0)/45.0,false);

filter->SetTransform(transform);


I expect this transform to map the output point
[1,0,0] to the input point [0,1,0]

However this line:

inputPoint = m_Transform->TransformPoint(outputPoint);

Yield the following value in the input point:
  
 [0] 2.2204460492503131e-016 double
 [1] 1.0000000000000000 double
 [2] -2.2204460492503131e-016 double

As a result, 

m_Interpolator->IsInsideBuffer(inputPoint)

fails and results in a garbled image.

Should this be filed as a bug to ITK?

Yasser



		
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