Alpha Shape Surface Model Generation for Anatomic Structures

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Solution Overview

Problem

Existing methods for generating surface models of anatomic structures, such as the heart, struggle to accurately reconstruct concave features due to the use of convex hull algorithms, which 'fill in' areas not reached by the catheter, resulting in a lack of detail in models.

Innovation Solution

The method involves collecting surface data points using a catheter and a computer system, processing these points to compute an alpha shape, and then generating a simplicial surface model by identifying key points and edges within the alpha shape to create a more detailed and accurate representation of the structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If convex hull algorithms are used to generate surface models, then the model construction is simple and areas not visited by the catheter are filled in, but concave features of the structure cannot be reconstructed

Engineering Contradiction:

Improvemodel construction simplicityVSAvoidconcave feature reconstruction accuracy

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent changes the mathematical parameter from convex hull to alpha shape, which introduces a new parameter (alpha value) that controls the level of detail and concavity preservation in the surface model, enabling accurate reconstruction of concave features while maintaining computational feasibility

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

Instead of filling in all gaps as the convex hull does, the patent inverts the approach by selectively preserving gaps that correspond to concave features, using the alpha shape algorithm to distinguish between areas that should be filled and areas that should remain as concavities

Inventive Principle:

Principle #13The other way round (Inversion)

2Reliability

If convex hull algorithms are used to generate surface models, then a complete model is created by filling in unvisited areas, but the level of detail is insufficient for many applications

Engineering Contradiction:

Improvemodel completenessVSAvoidanatomic feature detail

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent introduces the alpha parameter that controls the balance between model completeness and detail preservation, allowing the model to maintain reliability by filling genuine gaps while preserving anatomic detail through appropriate selection of alpha values

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS8253725B2Method and system for generating surface models of geometric structures

Publication Date: 2012.08.28 ST JUDE MEDICAL ATRIAL FIBRILLATION DIVISION INC

AI summary

A method and system of generating a surface model of an anatomic structure includes a catheter with which a plurality of location data points are collected from the surface of the anatomic structure. The method and system further includes a computer system that is configured to receive the collected data points from the catheter and to compute the alpha shape of collected data points to thereby generate a surface model of the anatomic structure. The computer system may be further configured to process the computed alpha shape to generate a simplicial surface model of the anatomic structure.