Visualizing a 3D volume dataset of an image at any position or orientation from within or outside
A machine-implemented display method that, with respect to a volume dataset being rendered, enables a user to navigate to any position in space and look in any direction. Preferably, the volume dataset is derived from a computer tomography (CT) or magnetic resonance imaging (MRI) scan. With the described approach, the user can see details within the dataset that are not available using conventional visualization approaches. The freedom-of-motion capability allows the user to go to places (positions) within the volume rendering that are not otherwise possible using conventional “orbit” and “zoom” display techniques. Thus, for example, using the described approach, the display image enables a user to travel inside physical structures (e.g., a patient's heart, brain, arteries, and the like).
1. An article comprising a tangible, non-transitory machine-readable medium that stores a program, the program being executable by a machine having a hardware component, comprising:
program code to receive a volume dataset defining a volume;
program code to ray trace the volume dataset using a plurality of rays, each ray, as it traverses the volume dataset, samples the volume dataset along a set of sampling points whose locations along the ray are determined as the ray is cast, wherein, for each pair of sampling points, a location of at least a next sample point along the ray is determined by a value of a voxel at a current sample point, together with a focus value, such that a distance between two sample locations varies dynamically; and
program code to use data generated by one or more ray traces to render the volume dataset as a 3D image.
2. The article as described in claim 1 wherein the volume dataset is received from a medical imaging scan.
3. The article as described in claim 1 wherein the image is rendered from a perspective that is external to the volume dataset.
4. The article as described in claim 1 wherein the image is rendered from a perspective that is internal to the volume dataset.
5. The article as described in claim 1 wherein a size of a step between a pair of samples along a ray associated with a pixel is a function of a value in the volume dataset at each sample point.
6. Apparatus, comprising:
a display;
a processor;
program code executed by the processor to ray trace the volume dataset using a plurality of rays, each ray, as it traverses the volume dataset, samples the volume dataset along a set of sampling points whose locations along the ray are determined as the ray is cast, wherein, for each pair of sampling points, a location of at least a next sample point along the ray is determined by a value of a voxel at a current sample point, together with a focus value, such that a distance between two sample locations varies dynamically; and
program code executed by the processor to use data generated by one or more ray traces to render on the display the volume dataset as a 3D image.
7. The apparatus as described in claim 6 wherein the 3D image is rendered from a perspective that is external to the 3D image.
8. The apparatus as described in claim 6 wherein the 3D image is rendered from a perspective that is internal to the 3D image.
9. The apparatus as described in claim 6 wherein the processor is one of: a CPU, and a GPU.
10. The apparatus as described in claim 6 wherein the 3D image is one of: a CT scan, and an MRI scan.
11. A display method, comprising:
receiving a volume dataset; and
ray tracing, using a hardware processor, the volume dataset using a plurality of rays, each ray, as it traverses the volume dataset, samples the volume dataset along a set of sampling points whose locations along the ray are determined as the ray is cast, wherein, for each pair of sampling points, a location of at least a next sample point along the ray is determined by a value of a voxel at a current sample point, together with a focus value, such that a distance between two sample locations varies dynamically; and
using data generated by one or more ray traces to render the volume dataset as a 3D image.
12. The display method as described in claim 11 wherein the image is rendered from a perspective of a virtual camera that is external to the volume dataset.
13. The display method as described in claim 11 wherein the image is rendered from a perspective of a virtual camera that is internal to the volume dataset.
14. The display method as described in claim 13 wherein an orientation of the virtual camera is adjusted from within a position internal to the volume dataset.
15. The display method as described in claim 11 wherein the volume dataset is received from a medical imaging scan.
16. The apparatus as described in claim 6 further including an input device.
17. The apparatus as described in claim 16 wherein data is received from the input device to simulate a user of the input device being positioned at any position in space, and to view in any direction, and with full freedom of motion, with respect to the 3D image.
18. The method as described in claim 11 wherein the 3D image is rendered to simulate a user of an input device being positioned at any position in space, and to view in any direction, and with full freedom of motion, with respect to the 3D image.