Some volumes are called image of labels, that is to say each part/structure of the volume is identified by a voxel value : a numerical label. For example, in the following image, the volume contains the background, the left and right hemispheres and the cerebellum. And each part is associated to a label : voxels have value 1 in the left hemisphere, 2 in the right hemisphere, and 3 in the cerebellum.
With this control, you can select regions according to a label. For example, if your volume V has the labels : 1, 2 and 3 :
- Load the volume V in Anatomist.
- Put it in a window and click on the ROI control.
- Create a ROI graph G and a region R to store your selection.
- In the window containing the volume V and the graph G, click on the label selection control
. - Click on a voxel which value is the required label.
- A warning message appears is data is huge, click on yes to go on.
- You will see better your region in a 3D window.
- The region R of the graph G now contains the selected region. You can store this ROI graph or export this region as a mask to get a volume.
- NB : in advanced use, you can substract sub-regions using the control's options.