Bone Contact Position Determination Using 3D Model Iterative Search

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Solution Overview

Problem

Current methods lack an efficient way to determine the six parameters of a contact position between two bones, which are essential for visualizing the range of motion and creating sample datasets for joints, particularly in medical applications such as knee joint analysis.

Innovation Solution

A data processing method that involves acquiring 3D models of bones, selecting initial values for four given parameters, and varying the remaining two parameters to achieve contact, using collision detection techniques and iterative searches to determine the optimal contact positions, thereby calculating the six parameters of a contact position.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If collision detection techniques and iterative searches are used to determine contact positions, then measurement precision of contact parameters is improved, but computing time and device complexity increase

Engineering Contradiction:
Improvecontact position parametersVSAvoidcomputing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The method performs preliminary actions by first acquiring 3D models of the bones and pre-defining the coordinate systems and parameter sets before the actual contact detection. This preparation work is done once, allowing the iterative search to focus only on finding the optimal contact position without repeatedly setting up the computational framework, thus reducing overall computing time while maintaining precision.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention uses 3D digital models (copies) of the actual bones instead of working with physical bone specimens. These digital replicas allow for rapid, repeated computational analysis without the time constraints and physical limitations of working with real bones, enabling precise iterative searches to be performed efficiently on computer systems.

Inventive Principle:
Principle #26Copying

2Measurement precision

If collision detection techniques and iterative searches are used to determine contact positions, then measurement precision of contact parameters is improved, but device complexity increases

Engineering Contradiction:
Improvecontact position parametersVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The computational system is designed with multi-functionality, where the same 3D modeling and collision detection framework can determine multiple contact position parameters (three translational and three rotational) simultaneously. This universal approach avoids the need for separate specialized devices for each parameter measurement, reducing overall system complexity while achieving high precision through comprehensive computational analysis.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The invention introduces 3D digital models as intermediaries between the physical bones and the measurement system. These digital representations serve as a mediator that translates complex physical contact problems into computable mathematical formulations, simplifying the measurement process while maintaining accuracy through the intermediary computational layer.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Loss of information

If six parameters of contact position are determined, then completeness of kinematic description is improved, but data processing complexity increases

Engineering Contradiction:
Improvekinematic informationVSAvoiddata processing complexity
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The complete contact position description is segmented into two distinct parts: four given parameters that define the primary contact configuration, and two remaining parameters that are iteratively determined through collision detection. This segmentation allows the complex six-parameter problem to be broken down into manageable computational steps, reducing data processing complexity while ensuring all kinematic information is captured.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The method systematically varies the two remaining contact parameters during the iterative collision detection process to find the optimal contact position. By changing these parameters in controlled steps and evaluating the collision state at each iteration, the system efficiently determines the complete six-parameter contact description without requiring exhaustive search of all possible parameter combinations, thus managing computational complexity.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2787887B1Method for determining contact position parameters of a joint connecting two bones
Publication Date: 2016.02.10 BRAINLAB AG
  • EP2787887B1 patent drawingFigure 1a~1b
  • EP2787887B1 patent drawingFigure 2a~2b
  • EP2787887B1 patent drawingFigure 3a

AI summary

A data processing method for determining six parameters, corresponding to six degrees of freedom, of a contact position of a joint which connects two bones, comprising the steps of acquiring a 3D model of each bone, acquiring four of the six parameters as given parameters, selecting initial values for the two remaining parameters and varying the two remaining parameters virtually in order to achieve a virtual relative position between the two 3D models such that they are in contact with each other.