Floating Volume-of-Interest Rendering via Inverse Vertex Transformation
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Solution Overview
Problem
Multilayer volume ray casting techniques face limitations in visualizing floating volumes-of-interest (VOIs) that can be moved freely in 3D space, as existing methods confine ray casting to a fixed bounding box, restricting the ability to apply transformations like translation, rotation, and mirroring without recalculating sampling locations.
Innovation Solution
The method involves transforming VOI vertices with operations such as translation, rotation, scaling, or mirroring, while maintaining the original sampling locations, and applying an inverse transformation before ray casting to allow for the rendering of floating VOIs with higher priority, enabling them to be moved freely within the 3D space without clipping by crop-boxes or cut-planes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If ray casting is confined to a fixed bounding box, then the implementation is simple and sampling locations are fixed, but the ability to visualize floating VOIs that can be moved freely in 3D space is restricted
Solution Approach 1:
Instead of transforming the sampling locations when moving the VOI, the patent applies an inverse transformation to the vertices of the mesh before ray casting. This inversion approach maintains fixed sampling locations while achieving the effect of moving VOIs, resolving the contradiction between adaptability and complexity
Solution Approach 2:
The patent performs transformation operations on the mesh vertices in advance before the ray casting process. By pre-transforming the vertices to account for VOI movement, rotation, or scaling, the system avoids complex real-time calculations during rendering, thus maintaining simplicity while enabling floating VOI visualization
2Ease of operation
If transformations like translation, rotation, and mirroring are applied to VOI vertices, then floating VOIs can be positioned freely, but recalculating sampling locations increases computational complexity
Solution Approach 1:
The patent inverts the transformation approach by applying transformations to mesh vertices rather than recalculating sampling locations. This allows free VOI positioning without the time-consuming recalculation of sampling locations, as the fixed sampling grid remains valid while the transformed vertices define the new VOI boundaries
Solution Approach 2:
The patent creates transformed copies of the mesh vertices to represent the floating VOI in its new position, orientation, or scale. These transformed vertex copies are used for rendering without requiring recalculation of the original sampling locations, thus saving computational time while achieving free VOI movement
3Adaptability or versatility
If crop-boxes or cut-planes clip the volume, then the rendering area is reduced, but floating VOIs with higher priority cannot be moved freely without being clipped
Solution Approach 1:
The patent introduces dynamic prioritization where floating VOIs can override static clipping planes when assigned higher priority. The system dynamically adjusts the rendering behavior based on VOI priority, allowing high-priority floating VOIs to move freely without being clipped by crop-boxes or cut-planes, while maintaining efficient rendering for lower-priority elements
Data Source
AI summary
A method that includes receiving vertices of a mesh, wherein the mesh represents a volume of interest (VOI) from an original volume, performing a transformation operation on the mesh, wherein the transformation operation transforms vertices of the mesh, obtaining sampling locations of the original volume using the transformed vertices, performing an inverse transformation on the transformed vertices of the mesh and the sampling locations, and performing a ray casting on the original volume to produce an image, wherein the ray casting uses the transformed vertices and a result of the inverse transformation as input.