<div><br></div>Hi ekyaya,<div><br></div><div><br></div><div>Line 199 of itkImageBase.hxx </div><div><br></div><div> says that your suspicions are well-founded:</div><div><br></div><div> this->m_IndexToPhysicalPoint = this->m_Direction * scale; <br>
<br>as well as lines 94-99 in the itkImageTransformHelper.h <br><br><div>94 inline static void TransformIndexToPhysicalPointCol(</div><div>95 const MatrixType & matrix,</div><div>96 const IndexType & index, DoublePoint & point,</div>
<div>97 const UniqueTypeBoolFalse &)</div><div>98 {</div><div>99 point[R] = point[R] + matrix[R][C] * index[C];</div><div><br></div><div><br></div>The matrix in the MetaImage headers shouldn't have</div>
<div>combined the spacing with the direction cosines. This</div><div>composition is done for you in line 99 of the ImageBase</div><div>class.</div><div><br></div><div>You may want to contact the organizers of the </div><div>
challenge and ask for clarification.</div><div><br></div><div><br></div><div> BTW, Is this Challenge data available to the public ?</div><div><br></div><div><br></div><div> Thanks</div><div><br></div><div><br></div>
<div> Luis<br><br><br>-------------------------<br><div class="gmail_quote">On Mon, May 21, 2012 at 6:14 PM, erkang <span dir="ltr"><<a href="mailto:ekyaya@gmail.com" target="_blank">ekyaya@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hi everyone:<br>
<br>
I play with the meta data downloaded from Liver challenge 2007. However, I<br>
confused with the "TransformMatrix" item in the header file.<br>
<br>
One example of the header file is as following:<br>
<br>
ObjectType = Image<br>
NDims = 3<br>
BinaryData = True<br>
BinaryDataByteOrderMSB = False<br>
TransformMatrix = 0.74219 0 0 0 0.74219 0 0 0 1.5<br>
Offset = 0 0 0<br>
CenterOfRotation = 0 0 0<br>
ElementSpacing = 0.74219 0.74219 1.5<br>
DimSize = 512 512 183<br>
AnatomicalOrientation = ???<br>
ElementSize = 0.58594 0.58594 1<br>
ElementType = MET_SHORT<br>
ElementDataFile = liver-orig001.raw<br>
<br>
I doubt that the header files of these data are not correct. I check the<br>
metaIO in ITK. ITK does first read the direction (TransformMatrix ) and then<br>
multiplied by spacing. I test it in ImageFileReader and transform of the<br>
loaded image is 0.74219*0.74219 0 0 0 0.74219*0.74219 0 0 0 1.5*1.5.<br>
<br>
But, I would like to guess the "TransformMatrix" of the header file is<br>
TransformMatrix = 1 0 0 0 1 0 0 0 1. And after multiplied by spacing, the<br>
actual transform matrix is 0.74219 0 0 0 0.74219 0 0 0 1.5.<br>
<br>
Is that correct? Or what's the best way to load these data? Thanks.<br>
<br>
--<br>
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