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The following steps are used to create a population average from a set of input specimen based on 3D volumetric data. In the example below,
3D anatomic landmark points placed on three input specimen guide the process to create a population average.
This is the method used in Stratovan Checkpoint's Population Average capability. Click here for more information on How to Create a Population Average using our Checkpoint software.
| Step 1 | Input specimen. Volume data (CT, MRI, etc.) with surfaces and a homologous set of 3D landmark points are placed on each specimen. Landmark points should be concentrated around features of interest. |  |
| Step 2 | The 3D landmark point sets are used to represent the population. Orientation and scale may be different among specimen. |  |
| Step 3 | Specimen landmark point sets undergo rigid alignment to remove orientation differences. Scale differences can be maintained or removed as desired. |  |
| Step 4 | Average pointset is computed using Generalized Procrustes Alignment (GPA) to remove scale (if desired). Resulting in the target average pointset (orange dots). |  |
| Step 5 | Each scan volume is warped to the average pointset using Thin-Plate Spline (TPS) warping. All deformed volumes are then merged together. |  |
| Step 6 | The resulting population average volume can be manipulated just as any of the original specimen volumes. Surfaces can be extracted, analyzed, and rendered from this average volume. |  |