1. A digital image editing method, comprising: receiving a three-dimensional volume image of an anatomical object of interest, wherein the volume image is characterized by first and second mutually exclusive segmentation classes; deriving a two-dimensional slice image from the volume image; selecting a single point on the slice image within the second segmentation class; and defining a plane in response to the selection of the single point, the plane dividing the second segmentation class into a target portion corresponding to the object and a remainder portion.