<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Hello,<div><br></div><div>As I mentioned before, I used the picker method from the NeedleTracker to get coordinates in mm from a CT image. However, I noticed that these values were not correct. When stepping through the slices 1 by 1, the values do not change as they should. For example, I have an image whose slices are 0.4 mm thick. The following table shows some slices and their reported z value as an illustration</div><div><br></div><div>Slice Z</div><div>0 48.115</div><div>1 48.115</div><div>2 49.872</div><div>3 49.872</div><div>4 50.753</div><div>5 50.753</div><div>6 50.753</div><div>7 50.753</div><div>8 51.635</div><div><br></div><div>This trend continues throughout the image. Here's the relevant portions of my code:</div><div><br></div><div><font class="Apple-style-span" face="Courier">From the constructor:</font></div><div><font class="Apple-style-span" face="Courier"><br></font></div><div><font class="Apple-style-span" face="Courier">typedef itk::ReceptorMemberCommand < Self > LoadedObserverType;</font></div><div><font class="Apple-style-span" face="Courier"><br></font></div><div><font class="Apple-style-span" face="Courier">m_ViewPickerObserverAxial = LoadedObserverType::New();</font></div><div><font class="Apple-style-span" face="Courier">m_ViewPickerObserverAxial->SetCallbackFunction( this, &CTDisplay_Implementation::PickerAxial );</font></div><div><font class="Apple-style-span" face="Courier"><br></font></div><div><font class="Apple-style-span" face="Courier">m_ImageSpatialObject = m_CTImageObserver->GetCTImage();</font></div><div><font class="Apple-style-span" face="Courier"><br></font></div><div><font class="Apple-style-span" face="Courier">m_AxialImageRepresentation = igstk::CTImageSpatialObjectRepresentationType::New();</font></div><div><font class="Apple-style-span" face="Courier">m_AxialImageRepresentation->RequestSetImageSpatialObject( m_ImageSpatialObject );</font></div><div><font class="Apple-style-span" face="Courier"><br></font></div><div><font class="Apple-style-span" face="Courier">m_AxialFLTKWidget->RequestSetView( ctAxialView );</font></div><div><font class="Apple-style-span" face="Courier">ctAxialView->RequestAddObject( m_AxialImageRepresentation );</font></div><div><font class="Apple-style-span" face="Courier">ctAxialView->RequestSetTransformAndParent( identityTransform, m_WorldReference);</font></div><div><font class="Apple-style-span" face="Courier"><br></font></div><div><font class="Apple-style-span" face="Courier">m_AxialImageRepresentation->RequestSetOrientation( igstk::CTImageSpatialObjectRepresentationType::Axial );</font></div><div><font class="Apple-style-span" face="Courier">ctAxialView->AddObserver( igstk::CoordinateSystemTransformToEvent(), m_ViewPickerObserverAxial );</font></div><div><font class="Apple-style-span" face="Courier"><br></font></div><div><font class="Apple-style-span" face="Courier"><br></font></div><div><font class="Apple-style-span" face="Courier"><br></font></div><div><font class="Apple-style-span" face="Courier">void CTDisplay_Implementation( const itk::EventObject & event )</font></div><div><font class="Apple-style-span" face="Courier">{</font></div><div><font class="Apple-style-span" face="Courier"> typedef igstk::CoordinateSystemTransformToEvent TransformEventType;<br></font></div><div><font class="Apple-style-span" face="Courier"> const TransformEventType * tmevent = dynamic_cast< const TraansformEventType *>( & event );</font></div><div><font class="Apple-style-span" face="Courier"> igskt::CoordinateSystemTransformToResult transformCarrier = tmevent->Get();</font></div><div><font class="Apple-style-span" face="Courier"> igstk::Transform transform = transformCarrier.GetTransform();</font></div><div><font class="Apple-style-span" face="Courier"> point = TransformToPoint( transform );</font></div><div><font class="Apple-style-span" face="Courier">}</font></div><div><font class="Apple-style-span" face="Courier"><br></font></div><div><font class="Apple-style-span" face="Courier"><br></font></div><div>Any thoughts would be appreciated.</div><div><br></div><div>Thanks,</div><div>Chris</div><div><font class="Apple-style-span" face="Courier"><br></font></div><div><font class="Apple-style-span" face="Courier"><br></font></div></body></html>