Figure 4. Direct 3D ultrasound visualization examples. This 3D ultrasound data set comprises 652 B-scans like the one at the bottom left of the figure. The planar and non-planar reslices are interpolated directly from these B-scans, using nearest neighbour interpolation. In this example, each "reslice" is in fact a narrow volume rendering of width 3 mm: this makes the resulting image far less dependent on the precise positioning of the plane or surface, and usefully highlights bony structures in this obstetric example. The B-scan display shows the intersection with the reslice volume, while the planar reslice display shows the intersection with both the B-scan plane and the non-planar reslice volume. All three displays are shown together in the multiplanar/non-planar reformat, in their correct relative positions. This display can be rotated interactively to give a better impression of the 3D geometry.