3D Editing

This mode is used for segmenting the data set into a number of components which can then be moved independently within the view control menu to allow surgical simulation. It displays an edit control window and selects a brush for painting on the image. The last two brushes sweep across the full extent of the window. The size of the spot brush is adjustable. By default, the entire image is marked in the current object colour so that the upper selection button will keep everything in the viewing window. Press the right mouse button in the main window and drag to unpaint a region of the image (leaving it marked in the aux colour) (this colour can be modified in the colour selection menu). Click and drag with the left mouse button to re-paint a region in the main colour. Once the regions are painted satisfactorily, the two selection buttons in the edit menu allow the choice of keeping either coloured region. The Undo Last Edit button reverses the effect of the last Keep This Region click. A 2D slice editing mode is also available for fine detail adjustment of edit state at the voxel level. 3D editing mode is not available when the Radiographic rendering mode is selected.
The painting tools are also used for defining a surface region when measuring its surface area using painted area in the Options menu.The area to be measured should be marked in the aux colour.

Dual Object Principle:

A total of eight objects (numbered 0 to 7) may be cut from the original data set. Multiple copies of the same part or overlapping copies are possible. At any one time, two of these objects may be tagged as having special status (Current & Aux.).The Current obj. is the one, from the available set of objects, which is being examined or operated upon. When editing an object, the discarded fragments can be put into the aux. object. This mode is selected by checking the Discards to Aux. obj box. By swapping the current and aux. objects, it is possible to move pieces back and forth between objects until a satisfactory edit is achieved. This is useful for example if it is necessary to isolate a complex shape such as a mandible from the skull. Note that editing is view dependent and that setting a different imaging threshold may show components that have not been edited as expected.

The buttons Current obj. and Aux. obj. display a list of objects to allow reselection. The highlighted image indicates the existing state of the system. Clicking on any image exits the list, selecting the chosen object. If an object selected to be the new "current obj" is already in the "Aux obj" state, the current and aux tags are automatically swapped.

The current object can, at any time, be emptied or restored to the full data set by clicking on the Empty Current Object or Restore Current Object buttons.

Each object can be mirror imaged about the vertical midline of the current view at any time. Clicking on the Mirrored Object List button displays a list of all objects with the mirrored ones tagged. Any of the tags can be flipped and the new state is implemented when the ok button is selected.When the mirrored state of an object is changed the object is left-right reflected through a vertical plane in the current view. This option allows the reconstruction of missing parts of anatomy by duplication and mirroring of existing contra-lateral parts.

The menu also contains a selection of different brush styles for painting regions. The first five brushes are the same size and shape as the white part of the cursor, the last two paint a stripe the full height or the full width of the screen respectively. If a region is outlined with a brush, the patch in the middle can be painted in by clicking on the flood fill button and then clicking, with either the left or right button as appropriate, inside the region to be filled. Only a region with a closed boundary will be filled. Clicking outside the main window aborts the flood fill mode.

Normally this mode only displays the current object being worked on.The show composite button causes an image of all the objects included in the composite set to be drawn. When HiRes is selected, images of the current and other objects are mixed together by dithering to produce a translucent effect. When HiRes is not selected, the images are depth sorted with the nearer surfaces obscuring more distant surfaces. The control menu changes to show its altered function. The composite list button allows the user to change which objects are included in this set.

Duplicate Current Object causes a copy of the current object to be created in the next available object. The number chosen is reported by the system. Creating a duplicate is often useful when mirror imaging a contralateral part of the data to simulate the reconstruction of a missing part of the anatomy.

Complement of Current Object causes a copy of what is NOT in the current object to be created in the next available object. The number chosen is reported by the system. This is often useful if you have forgotten to check the Discards to Aux. obj box.

Complement of All Objects causes a copy of what is NOT in any of the objects to be created in the next available object. This allows "lost" bits to be recovered..

Having edited a data set, the "save edit" option in the file menu allows the information to be saved to a disc file for later retrieval.

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©2005-2007 Robin Richards. All rights reserved.