3D Volume Rendering With Surface-Normal Color Sampling
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Solution Overview
Problem
Rendering three-dimensional volumes onto two-dimensional displays is computationally expensive, especially when the display is not aligned with the volume edges, and existing methods result in monochrome outlines of surfaces of interest, lacking detail and requiring extensive computational resources.
Innovation Solution
A method that sequentially steps through points along a line of sight from each pixel into the three-dimensional volume, determining a first point on a surface of interest and a second point normal to it, using the second point's value to determine the pixel color, thereby rendering subtle color differences that reflect neighboring structures while conserving computational resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If ray-marching with compositing is used to render three-dimensional volume, then information detail is preserved, but computational cost increases significantly
Solution Approach 1:
The patent extracts only the necessary information for rendering by identifying and using only the first voxel along each ray that meets the transfer function criteria, rather than compositing all voxels. This extraction approach preserves the visual information needed for the rendered image while eliminating unnecessary computational operations on remaining voxels.
Solution Approach 2:
The patent applies partial action by performing the computationally expensive compositing operation only once per ray (when the first relevant voxel is found) rather than continuously for all voxels along the ray. This partial application of the compositing operation maintains information quality while dramatically reducing computational load.
2Productivity
If early ray-marching (stopping at threshold) is used to improve computational efficiency, then processing speed increases, but color information is lost resulting in monochrome outlines
Solution Approach 1:
The patent introduces an intermediary mechanism where the transfer function acts as a smart selector that identifies voxels with relevant color information. By using the transfer function to filter and select only the first voxel that contributes meaningful color data, the system avoids the monochrome problem while maintaining computational efficiency through early termination of the ray-marching process.
3Adaptability or versatility
If the display is not aligned with volume edges, then flexibility in display orientation is improved, but interpolation requirements increase computational cost
Solution Approach 1:
The patent applies local quality by performing interpolation only at the specific location where it is needed - at the first voxel along each ray that meets the transfer function criteria. Rather than pre-interpolating the entire volume or performing continuous interpolation, the method locally applies interpolation only when and where required, reducing overall computational complexity while maintaining display orientation flexibility.
Data Source
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AI summary
A method 100 of displaying a three dimensional volume of an image on a two dimensional display. For each pixel in the two dimensional display, the method comprises sequentially stepping 102 through a plurality of points along a line of sight from the pixel into the three dimensional volume and determining 104 a first point along the line of sight at which the three dimensional volume has a value that satisfies a first criteria indicating that the first point comprises a surface of interest in the three dimensional image. From the first point, the method then comprises determining 106 a second point that lies normal to the surface of interest at the first point, and determining 108 a value for the pixel based on a first value associated with the second point.