Slab Polygon Trimming for Empty Space Skipping in Volume Rendering
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing volume rendering techniques, such as sliding texture volume rendering, are inefficient in skipping empty spaces within three-dimensional data sets, as they require extensive slab polygon geometry that is not optimized for empty space skipping, leading to increased computational load.
Innovation Solution
The method involves trimming slab polygons by identifying the first and last visible voxels in each data row and column, storing their bounds, and marking invisible sections, allowing for efficient skipping during rendering by restricting rendering to the minimum and maximum bounds of visible data rows and columns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If block-based empty space skipping techniques are used, then rendering performance is improved, but the complexity of the volume decomposition increases due to additional block-based decomposition on top of slab-based decomposition
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing the minimum and maximum bounds of visible voxels for each data row and column before rendering. This pre-computed bounding information is then used during the rendering phase to quickly identify and skip empty spaces without requiring complex runtime decomposition analysis, thus improving performance while avoiding additional decomposition complexity.
Solution Approach 2:
The patent extracts only the essential bounding information (minimum and maximum voxel indices) from the volume data along each row and column, storing this extracted information in a compact data structure. This extraction approach avoids the need for complex block-based decomposition while still enabling efficient empty space identification and skipping during rendering.
2Reliability
If slab polygon geometry is used for rendering, then volume visualization is achieved, but computational load increases due to extensive polygon geometry that cannot be optimized for empty space skipping
Solution Approach 1:
The patent applies local quality by varying the rendering behavior across different regions of the volume based on local visibility characteristics. For each data row and column, the algorithm identifies specific bounding regions where visible voxels exist and applies rendering only to those local regions, while skipping empty spaces. This localized rendering approach maintains visualization quality in visible areas while reducing computational load in empty regions.
Solution Approach 2:
The patent segments the volume rendering task by dividing it into independent data rows and columns, each with its own bounding information. This segmentation allows the rendering system to process and skip empty regions independently for each row and column, rather than treating the entire volume as a single rendering task, thereby reducing overall computational load while maintaining visualization quality.
Data Source
AI summary
A method for volume rendering a digitized image includes providing a pair of adjacent 2-dimensional images of texture data, identifying a plurality of polygons extending in slabs between said adjacent two dimensional textures, and finding the first and last visible voxel for the data rows and data columns of each said polygon. The minimum and maximum bounds of each data row and for each data column are determined, those data rows and data columns that do not contain any visible voxels are marked as invisible, and the polygons are rendered along a direction orthogonal to a dominant viewing direction, wherein rendering of texture data is restricted by the outer bounds of polygons that are trimmed to the minimum and maximum bounds of two neighboring data rows or data columns, and wherein those data rows and data columns marked as invisible are skipped.