Irregular volumes within one or more three-dimensional volume datasets are
identified and extracted in response to criteria. The processing involves
automatically finding a seed voxel or seed cell that meets the criteria
and thus belongs to an irregular volume of interest, and then identifying
cells related to the seed cell by one or more predetermined relationships
that are therefore also to be grouped into that irregular volume.
Information, which can be of any suitable type, identifying each such
cell as being related to other cells and belonging to an irregular volume
is stored in a suitable data structure. The location or similar
neighborhood information and other data describing properties or
attributes of the identified cell are also stored. Because the irregular
volumes are extracted and pre-processed in this manner, operations
including rendering them on a display and performing Boolean and
arithmetic operations on them can readily be performed.