[Insight-users] Changes in itkAffineTransform.txx from 181 to 201

[Ashish Poddar]

Hi,
I was running a program that was working fine in ITK 1.8.1. Recently I
installed ITK 2.0.1 and it started behaving in unexpected way...

What I was doing : Rotating in 3D using Centered Affine Transform and
computing the metric to find an initial estimate for the angle


for (double angle=initangle; angle<=finalangle; angle+=stepsize)
{
     double rot_angle = (angle) * PI / 180; // radians
     transform->SetIdentity();
     transform->SetCenter( center );
     transform->SetTranslation(trans);
     transform->Rotate3D( axis, rot_angle );
// some processing
}

in the new version it started giving me weird error saying image is
out of range!! so metric cant be computed ... I debugged it a bit to
find the cause... Rotate3D function was somehow assigning some weird
values for the translation !!

I traced the source of this error back to itkAffineTransform.txx...
and there was surely a change in the code

From:
  ......
  // Compose rotation matrix with the existing matrix
  if (pre) 
    {
    m_Matrix = m_Matrix * trans;
    }
  else 
    {
    m_Matrix = trans * m_Matrix;
    m_Offset = trans * m_Offset;
    }
  RecomputeInverse();
  return;
}


To:
  ......
  // Compose rotation matrix with the existing matrix
  if (pre) 
    {
    m_Matrix = m_Matrix * trans;
    }
  else 
    {
    m_Matrix = trans * m_Matrix;
    m_Offset = trans * m_Offset;
    }
  this->ComputeTranslation();
  m_MatrixMTime.Modified();
  this->Modified();
  return;
}


Why is Translation being computed in Rotate3D function?? is it by
design or some coverup for some other bug??

any idea on this would be highly appreciated 

with regards,
Ashish.

-- 
Ashish Poddar
Have an acceptable reason for accepting anything.
Y:ashish_poddar | MSN:ashish_poddar at yahoo.comfor (double
angle=initangle; angle<=finalangle; angle+=stepsize)

-- 
Ashish Poddar
Have an acceptable reason for accepting anything.
Y:ashish_poddar | MSN:ashish_poddar at yahoo.com