Methods, systems, and computer program products for processing three-dimensional image data to render an image from a viewpoint within or beyond an occluding region of the image data

A system for processing three-dimensional image data to render an image from a viewpoint within or beyond an occluding region of the image data, the method comprising:

• (a) a surface rendering module for accessing a set of three-dimensional image data including image data for a surface of interest and image data for a region occluding the surface of interest from a desired viewpoint and for:
• (i) casting a plurality of rays from the viewpoint to the surface of interest;
• (ii) along each ray, making an occlusion determination independently from a volume rendering transfer function definition to render voxels within the occluding region as transparent or partially transparent;
• and
• (iii) applying the volume rendering transfer function along a portion of each ray outside of the occluding region to render voxels defining the surface of interest as visible, wherein the surface rendering module is adapted to apply a first transfer function to render the voxels of the surface of interest as visible and to apply a second transfer function different from the first transfer function to render the voxels of the occluding region as transparent or semi-transparent;
• and
• (b) a display module for displaying the voxels that define the surface of interest from the viewpoint as visible and for displaying the voxels within the occluding region as transparent or partially transparent.

A non-transitory computer program product comprising computer-executable instructions embodied in a computer-readable medium for performing steps comprising:

• (a) receiving a set of three-dimensional image data including image data for a surface of interest and image data for a region occluding the surface of interest from a desired viewpoint;
• (b) casting a plurality of rays from the viewpoint to the surface of interest;
• (c) along each ray, making an occlusion determination independently from a volume rendering transfer function definition to render voxels within the occluding region as transparent or partially transparent;
• (d) applying the volume rendering transfer function along a portion of each ray outside of the occluding region to render voxels defining the surface of interest as visible;
• and
• (e) displaying the voxels that define the surface of interest from the viewpoint, wherein the voxels within the occluding region are shown in a transparent or partially transparent manner and wherein the voxels that define the surface of interest are shown as visible, wherein applying a transfer function includes applying a first transfer function to render the voxels of the surface of interest as visible and applying a second transfer function different from the first transfer function to render the voxels of the occluding region as transparent or partially transparent.