Segmented Volume Rendering Mask Boundary Artifacts
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Solution Overview
Problem
Existing volume rendering techniques face challenges in reducing the discrepancy between mask boundaries created by segmentation masks and those implicitly defined by transfer functions, leading to rendering artifacts at segmentation mask boundaries.
Innovation Solution
A method and system for segmented volume rendering that involves modifying voxel data associated with segmentation masks by setting specific portions to uniform values and applying operators to reduce the visibility of mask boundaries, using techniques like trilinear interpolation and gradient operators to create a more natural boundary image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If segmentation masks are used to define masked structures in volume rendering, then specific regions can be excluded from rendering, but rendering artifacts occur at segmentation mask boundaries due to discrepancy between mask boundaries and transfer function boundaries
Solution Approach 1:
The patent applies preliminary action by modifying voxel data at segmentation mask boundaries before the actual volume rendering process. Specifically, it identifies voxels at the boundary of segmented regions and adjusts their density values in advance to account for the discrepancy between the sharp mask boundary and the softer transfer function boundary. This preprocessing step ensures that when rendering occurs, the boundary artifacts are already mitigated, combining the ease of mask creation with improved boundary accuracy.
2Adaptability or versatility
If transfer functions are applied to control opacity and visibility of volume structures, then selective visualization of structures is achieved, but boundary surfaces implicitly defined by transfer functions differ from explicit segmentation mask boundaries
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the density values of voxels at segmentation mask boundaries. It modifies the voxel data parameters (density values) in the transition zone between masked and unmasked regions to create a smoother gradient that better aligns with the transfer function's implicit boundary. This allows the system to maintain visualization flexibility while improving boundary alignment accuracy.
3Manufacturing precision
If voxel data is modified at segmentation mask boundaries to reduce artifacts, then boundary quality improves, but additional processing steps are required
Solution Approach 1:
The patent applies local quality by focusing modifications only on the specific region where the problem occurs - the voxels at segmentation mask boundaries. Instead of processing the entire volume dataset uniformly, it identifies and modifies only the boundary voxels that contribute to rendering artifacts. This localized approach improves boundary quality while minimizing additional processing complexity by avoiding global data modification.
Data Source
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AI summary
Visualizing of volumetric data with masked segements using a rendering technique in which voxels are sampled along a ray through a volume, the technique includes obtaining voxel data, modifying a first portion of the voxel data, the first portion of the voxel data associated with a first segmentation mask. The modifying includes setting the first portion of the voxel data to at least one of a plurality of permitted voxel values, e.g. the maximum voxel value for which the opacity is zero as is the opacity of all smaler values. The technique further includes applying a set of operators to the modified first portion of the voxel data and a remaining portion of the voxel data and displaying the volume based on the applied first set of operators. The technical problem is the reduction of discrepancies between a mask boundary created by a segmentation mask and a boundary implicitly defined by a transfer function.