A data processing methodology and corresponding apparatus for visualizing the characteristics of a particular object volume in an overall medical/biological environment receives a source image data set pertaining to the overall environment. First and second contour surfaces within the environment are established which collectively define a target object volume. By way of segmenting, all information pertaining to structures outside the target object volume are excluded from the image data. A visual representation of the target object based on nonexcluded information is displayed. In particular, the method establishes i) the second contour surface through combining both voxel intensities and relative positions among voxel subsets, and ii) a target volume by excluding all data outside the outer surface and inside the inner surface (which allows non-uniform spacing between the first and second contour surfaces). The second contour surface is used as a discriminative for the segmenting.