Hi Nathaniel,<br><br>The Landmark3DRegistrationErrorEstimator in IGSTK is implementation of the TRE derivation by West et al.<br><br>J.B West et al, "Fiducial Point Placement and the Accuracy of Point-based, Rigid Body Registration", Neurosurgery, pp 810-816, Vol.48, No.4, April 2001.<br>
<br>You mentioned in your email a Matlab script implementation. Is this script a full implementation of the TRE equation in Matlab or is it a script that calls igstk::landmark3DRegistrationErrorEstimator to compute TRE?<br>
<br>If your Matlab implementation is independent of IGSTK and if both implementations produce the same result, then we will need to look into the derivation to understand your observation.<br><br>Let us know.<br><br>-Andinet<br>
<br><br><br><br><br><div class="gmail_quote"><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><div> </div>
<div>I'm conducting a study into fiducial configurations and their related TRE. I used the algorithm presented in igstkLandmark3DRegistrationErrorEstimator to develop a MATLAB script to calculate the TRE for given image landmarks, FRE, and a target point. However, when I vary the target point by its x-coodinate I receive the same TRE for a given fiducial configuration. This is not experienced when I vary the y- or z-coodinates of the target point. I validated the MATLAB script with Landmark3DRegistrationErrorEstimatorExample::ErrorEstimator1 in IGSTK-Sandbox v2.0 and received the same results. </div>
<div> </div>
<div>Has anyone else experienced this situation or can provide enlightenment for a solution?</div>
<div> </div>
<div>Thanks for your time and help,</div>
<div>Nathaniel Hamming</div>
<div> </div>
<div>FYI: I included the image landmarks, track landmarks, and target points that were used to validate the script using Landmark3DRegistrationErrorEstimatorExample::ErrorEstimator1 along with the resulting TRE.</div>
<div> </div>
<div><u>Image Landmarks:</u></div>
<div>(0.114845139504747 -84.6604824506397 -6.26710676551675)<br>(72.9584125146068 6.53918641170636 32.1024344060193)<br>(-80.5111003508657 4.75960126764604 40.0533742041848)<br>
(58.1672017212154 -47.5649370736371 -12.6361990926914)<br>(-54.487081424932 -55.2545031775054 -26.0381247399557)<br>(75.5947613145267 29.6918711527396 11.7797978481002)<br>
(-84.5277722958269 26.1312335752415 12.7930502907778)<br>(60.4385919682889 -13.0993934111475 -31.2299212457651)<br>(-65.2827107691361 -21.1801171028438 -34.2503757501768)<br>
(2.04690415405402 -41.7124883445493 -64.6657459246422)<br>(-73.3214245559623 -19.8518398326938 -3.984626698198)<br>(69.9212556595938 -1.46702964398868 -0.472367941194386)<br>
(-25.6974808869996 -75.065947078444 -33.4563926906414)<br>(33.8170959437249 -63.0341849792339 -37.9607564776401)</div>
<div> </div>
<div><u>Tracker Landmarks:</u></div>
<div>(46.600717682397 -30.8121035263332 -885.990194627345)<br>(128.792976006704 44.5188525815836 -935.56621842578)<br>(127.021257370086 -107.728230217206 -949.701561980191)<br>
(82.9686506055305 27.1399645537516 -882.972750919913)<br>(79.6707385764108 -85.7007660779085 -874.429003896307)<br>(154.517592060753 46.6545433797318 -919.449505921427)<br>
(152.644949852231 -112.921598475625 -926.667845321769)<br>(120.254718830609 28.8688629954591 -870.901038232264)<br>(114.048783584512 -96.1666948609119 -872.597788374716)<br>
(98.5072568480499 -30.8629325840406 -835.649463957748)<br>(110.292486691374 -102.893696403642 -902.229885054371)<br>(126.40396743689 39.8625678957445 -902.309420522653)<br>
(60.4020948254781 -57.3617285910359 -862.234734609912)<br>(72.5897769707638 1.66170144246608 -856.570128840823)</div>
<div> </div>
<div><u>Target Points:</u></div>
<div>1 - (-83.5623069243003 -4.91518218770797 32.0031623919239)</div>
<div>2 - (-6.28957965157304 -4.91518218770797 32.0031623919239)</div>
<div>3 - (70.9831476211542 -4.91518218770797 32.0031623919239)</div>
<div>4 - (-6.28957965157304 -104.915182187708 32.0031623919239)</div>
<div>5 - (-6.28957965157304 15.084817812292 32.0031623919239)</div>
<div>6 - (-6.28957965157304 95.084817812292 32.0031623919239)</div>
<div>7 - (-6.28957965157304 -4.91518218770797 -76.1786557898943)</div>
<div>8 - (-6.28957965157304 -4.91518218770797 1.09407148283303)</div>
<div>9 - (-6.28957965157304 -4.91518218770797 78.3667987555603)</div>
<div> </div>
<div><u>TRE^2 (results from Landmark3DRegistrationErrorEstimatorExample::ErrorEstimator1) :</u></div>
<div>
<div>1 - 0.054657382367051761<br>2 - 0.054657382367051761<br>3 - 0.054657382367051761<br>4 - 0.12959851653502544</div>
<div>5 - 0.070150472712894457</div>
<div>6 - 0.23372722469439022 </div>
<div>7 - 0.085080085180609902</div>
<div>8 - 0.033015214490287000</div>
<div>9 - 0.13262218720315677<br> </div></div>
<div> </div>
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