Hi Agata,<div><br></div><div>You are not seeing errors because you are mapping</div><div>the very same input landmarks, and because in its </div><div>default setting the TPS transform is an interpolating</div><div>spline (which means that it actually passes by the </div>
<div>landmark points.</div><div><br></div><div>This applies to all the Transforms deriving from:</div><div><a href="http://www.itk.org/Doxygen/html/classitk_1_1KernelTransform.html">http://www.itk.org/Doxygen/html/classitk_1_1KernelTransform.html</a> <br>
<br>You can change the behavior of the TPS from an Interpolating</div><div>spline to an Approximating Spline by changing the value of the</div><div>Stiffness parameter with the method:</div><div><br></div><div><a href="http://www.itk.org/Doxygen/html/classitk_1_1KernelTransform.html#a82a5f8a507dd4a8bc9c55972722f9f34">http://www.itk.org/Doxygen/html/classitk_1_1KernelTransform.html#a82a5f8a507dd4a8bc9c55972722f9f34</a> <br>
<br>"
<span style="font-family:'Lucida Grande',Verdana,Geneva,Arial,sans-serif;font-size:11.666666030883789px;background-color:rgb(251,252,253)">Stiffness of the spline. A stiffness of zero results in the standard interpolating spline. A non-zero stiffness allows the spline to approximate rather than interpolate the landmarks. Stiffness values are usually rather small, typically in the range of 0.001 to 0.1.</span> "</div>
<div><br></div><div>When you use it as an approximating spline, the deformation</div><div>will be smoother, and the target points of the input landmarks</div><div>will no longer coincide with the target landmarks.</div><div>
<br></div><div><br></div><div> HTH</div><div><br></div><div><br></div><div> Luis<br><br><br>-----------------------------------------------------------------------<br><div class="gmail_quote">On Mon, Aug 20, 2012 at 2:01 PM, Agata Krasoń <span dir="ltr"><<a href="mailto:agatakrason@gmail.com" target="_blank">agatakrason@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div>Hi Luis,</div><div><br></div>Thank You very much for explain this area .<div>Thanks Luis ! </div><div>But If I have position of points after registration (after transformation TPS) I don't need exacly all of matrices and components of TPS.</div>
<div>But I not sure if these positions of point are good after TPS transformation. Is there anything with errors ?</div><div>When I was trying test rigid or affine. I received always values weighted small errors (about 0,1 - 0,5 between measured values and registered values).</div>
<div>Now with TPS - anything with errors. I don't see error between values. (all the same) ???</div><div><br></div><div><br></div><div><br></div><div>Regards,</div><div>Agata</div><div class="HOEnZb"><div class="h5">
<div><br></div></div></div></blockquote></div></div>