Patent ID: 8294706

Claim:
A method of volume rendering, the method comprising: sampling, with a processor, a plurality of first rays in a first spatial density through a volume, each first ray being in a separate section; comparing, with a processor, a value of at least one first ray to a first threshold; sampling, with a processor, a plurality of second rays in a second spatial density based on the comparison of the at least one first ray, the second rays being in a first spatial section of the separate sections, the first section being for the at least one first ray and including a first perimeter formed by coordinates on edges of the first section; comparing, with a processor, a value of at least one second ray to a second threshold; sampling, with a processor, a plurality of third rays in a second section spatially different than the first section and at the second spatial density based on the comparison of the at least one first ray and the comparison of the at least one second ray, the second section spatially different than the first section by having a second perimeter formed by coordinate on edges of the second section, where coordinates in an interior of the second perimeter are outside the first perimeter; and displaying an image rendered from the sampling of at least the first rays.