Hi Agata,<br><br><div class="gmail_quote"><div>.. <br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><font color="#ff0000">Is it any possibility to return matrix of TPS transform ?</font></div>
<div><br></div></blockquote><div><br>Not quite.<br><br>The TPS is more complex than an Affine transform, <br>and cannot be fully expressed just with a nxn Matrix.<br><br>One could however, "approximate" it with an Affine transform<br>
and in this way reduce it to a Matrix, if you are willing to accept<br>the loss of deformation representation that it will imply.<br><br>The TPS is representing the equivalent of taking a thin metallic bar <br>
and bending it to force it to pass through several points in space.<br>
That deformation can not be represented by an affine matrix only.<br>
<br><br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div></div><div>The same for example in rigid transformation (itkVersorRigid3DTransform)</div><div>I could return matrix 4x4 rotation & translation </div>
<div><br></div></blockquote><div><br>Yes, this is because a Rigid transform can be fully represented <br>by a Matrix. This is possible for the family of Affine Transforms<br>(of which Rigid 3D is a member)<br> <br><br></div>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div></div><div><font color="#ff0000">But I don't know. What is it in itkThinPlateSplineKernelTransform ?</font></div>
<div><br></div></blockquote><div><br>The TPS transform can not be fully represented by a matrix.<br><br>You could however get a gross approximation of a TPS using matrices,<br><br>You can find these pieces in <br><br><a href="http://www.itk.org/Doxygen/html/classitk_1_1KernelTransform.html#a8819c174198218c4054511df7affeb94">http://www.itk.org/Doxygen/html/classitk_1_1KernelTransform.html#a8819c174198218c4054511df7affeb94</a><br>
<a href="http://www.itk.org/Doxygen/html/classitk_1_1KernelTransform.html#a7d4a5477c9df969edd0d91aae2cca05a">http://www.itk.org/Doxygen/html/classitk_1_1KernelTransform.html#a7d4a5477c9df969edd0d91aae2cca05a</a> <br><br><br>
</div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div></div></blockquote><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div>I am trying to save tps transform with :TransformFileWriter</div><div>I can't receive good results.</div><div>I receive only parameters sources and targets. Something like this :</div><div><div><font color="#ff0000">#Insight Transform File V1.0</font></div>
<div><font color="#ff0000"># Transform 0</font></div><div><font color="#ff0000">Transform: ThinPlateSplineKernelTransform_double_3_3</font></div><div><font color="#ff0000">Parameters: -81.29 -31.07 -770.58 -83.11 -21.26 -822.64 -93.45 -32.44 -858.72 -68.08 -126.89 -813.07 -61.04 75.74 -808.36</font></div>
<div><font color="#ff0000">FixedParameters: 140.6 230.7 -30.5 140.2 231.7 -71.1 144.8 235.9 -116.1 45.8 220.2 -66.7 231.6 211.3 -66.1</font></div></div><div><font color="#ff0000"></font></div><div><br></div></blockquote>
<div><br><br>Yes, <br>This is normal...<br><br>Since these are the key points of <br>information that fully define the Transform.<br><br>4x4 Matrices can only represent Affine transforms<br>(rotation, shearing, scaling and translation). <br>
<br>4x4 Matrices can not represent deformations such as <br>the ones managed by the family of KernelTransforms <br>and the BSplineDeformableTransforms.<br><br><br> HTH<br><br><br> Luis<br><br></div></div>