Shell Lorensen

In this mode, you create 3D polygonal surfaces from the Tag images you created with the TAG Module.

In Lorensen’s algorithm, the surface will be half a pixel wider than the center of the tag voxels. The surface will be slightly larger and contain more polygons than the surface created in the TomoVision mode.

Note:

The shell computation is only available for 3D and sorted parallel groups.

From the Graphic Interface

TAG Value

Select the current Tag value. A surface will be created around each of the selected Tags

Conditions

These buttons control the surface creation conditions. For each selected Tag value, a surface will be created on the border of a Tag pixel if:

•The Tag value is greater than the Tag value of its neighbour

•The Tag value is smaller than the Tag value of its neighbour

•The Tag value is on the border of the volume

Threshold

Interpolation

If your dataset has been segmented using one of the threshold based segmentation modes (Threshold, Region Growing, Histogram Segmentation...), then a threshold value has been assigned to each Tag. You can use these values to interpolate the position of the nodes of the reconstructed geometry between the voxels to obtain a smoother surface.

When "Threshold Interpolation" is on, the "Edit Threshold" button is accessible. Activating this option will change the values displayed on the Tags buttons from their names, to their assigned threshold values. You can edit these values with a right click on the Tag buttons.


Threshold Interpolation: Off	Threshold Interpolation: On

Create Geometry

Clicking this button will cause sliceOmatic to compute the 3D shell around all the selected Tags

Example of reconstructions with different conditions.


The original TAG image: Outside = TAG 1, circle = TAG 2, cross = TAG 3	Shell of TAG 2 with the condition Greater	Shell of TAG 2 with the condition Smaller

Shell of TAG 2 with the condition Border	Shell of TAG 2 with the condition Greater & Smaller	Shell of TAG 2 with the condition Greater & Smaller & Border