0003743: Markups under non-linear transform can break the slice viewer - MantisBT

ID	Project	Category	View Status	Date Submitted	Last Update

0003743	Slicer4	Module Markups	public	2014-06-21 21:34	2014-06-24 06:32

Reporter	lassoan	Assigned To	nicole
Priority	normal	Severity	minor	Reproducibility	always
Status	assigned	Resolution	open
Product Version
Target Version		Fixed in Version

Summary	0003743: Markups under non-linear transform can break the slice viewer
Description	Non-linearly transformed markups may disappear and make the slice viewer unresponsive. Load MRHead sample Load the attached non-invertible-bspline.tfm transform Go to axial slice S=20.786mm Add a markup at about RAS=(-50,-40,20.8) => the markup appears on the slice Drag the markup to RAS=(-27,34,20.8) => ERROR: the markup disappears Try to zoom in/out by right-clicking and dragging the mouse => ERROR: a hand icon is shown and zoom does not work (translating the image, window width/level, etc. don't work either) Probably the issue is that non-linear transforms are not always invertible and so when the user adds a transformed fiducial position in the RAS coordinate system then it may not be possible to find the non-transformed position (RAS coordinate transformed with the inverse of the transform). A solution might be to check if TransformToWorld(TransformFromWorld(input_RAS)) == input_RAS. If not, then the inverse does not exist and we may refuse to add the fiducial at that requested RAS position (or refuse to move an existing fiducial to that RAS position). It would be also useful to show a warning icon at the fiducial if TransformFromWorld(TransformToWorld(fiducialPosition_Local)) == fiducialPosition_Local fails for existing markup points, because it means that although the fiducial can be transformed, but the inverse transform is not available at that position. Availability of the inverse transform (TransformFromWorld) is important, because images are displayed by using that transform, so if it does not exist or not accurate then the displayed transformed fiducial position will inconsistent with the displayed transformed image.
Tags	No tags attached.

2014-06-21 21:37	non-invertible-bspline.tfm (8,185 bytes)

nicole 2014-06-24 06:32 administrator ~0012096	Discussion at project week: Want to provide a sensible user experience, some options: have the drag operation end when reach a non valid point (in 2d going off plane?) have the fiducial stop at the last valid point when draggging then jump to the next valid point as the user continues to drag (confusing? will the vtkSeedWidget drop it after a certain distance? only update the MRML node with valid positions) hide fiducials that can't be transformed when the list is place under a new transform lock and visually mark a fiducial if it can't be moved lock the whole list from mouse interactions if can't transform all points (not useful, the example non linear transform only has a few smallish regions where the inverse doesn't work) To consider: When dragging a seed that is under a transform, can I calculate the requested position including the transform (temp seed?) rather than going from screen space? Do I have the previous position to calculate delta. Revisit rulers under non linear transform, they're disappearing (will rotate to volume space help if under same xform?).

Date Modified	Username	Field	Change
2014-06-21 21:34	lassoan	New Issue
2014-06-21 21:34	lassoan	Status	new => assigned
2014-06-21 21:34	lassoan	Assigned To	=> nicole
2014-06-21 21:37	lassoan	File Added: non-invertible-bspline.tfm
2014-06-24 06:32	nicole	Note Added: 0012096