Image Registration via Optical Tracking and Surface Matching

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Solution Overview

Problem

Current methods for automatic registration of anatomical body parts in medical imaging require fiducials that can cause artifacts and distract from anatomical information, complicating the image quality and manufacturing process.

Innovation Solution

A method using a reference device with optical markers, where a geometric model of the device is scanned alongside the anatomical body part, allowing for positional mapping between image and tracking reference systems through surface matching algorithms, eliminating the need for image-visible fiducials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If fiducials are used for automatic registration, then registration accuracy is improved, but image quality deteriorates due to artifacts and distraction from anatomical information

Engineering Contradiction:

Improveregistration accuracyVSAvoidimage quality

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the registration function from the image space by using a separate tracking reference system with optical markers. The fiducials are removed from the scanned image volume, and registration is achieved through matching the tracked reference device geometry with its detected marker positions, eliminating image artifacts while preserving registration accuracy

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces a tracking reference system as an intermediary between the anatomical body part and the navigation system. This mediator uses optical markers on a reference device that is tracked separately from the medical imaging modality, allowing registration without requiring fiducials to be visible in the medical images

Inventive Principle:

Principle #24Intermediary (Mediator)

2Manufacturing precision

If fiducials are embedded into a registration device with high accuracy, then registration precision is improved, but manufacturing and assembly complexity increases

Engineering Contradiction:

Improveregistration precisionVSAvoidmanufacturing and assembly efforts

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical/embedded fiducial system with an optical tracking system. Instead of embedding physical fiducials into the reference device, the system uses optical markers that can be attached to or integrated with a simpler reference device structure, reducing manufacturing complexity while maintaining registration precision through optical detection

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent creates a geometric model (copy) of the reference device that is matched against the tracked marker positions. This virtual model allows the system to achieve high registration precision without requiring complex physical embedding of fiducials, as the matching process operates on the geometric representation rather than physical fiducial placement

Inventive Principle:

Principle #26Copying

3Extent of automation

If the entire registration device is made visible in the scan, then automatic registration is enabled, but anatomical information becomes distracted and harder to interpret

Engineering Contradiction:

Improveautomatic registrationVSAvoidanatomical information clarity

Core Design Contradiction:

Extent of automationVSLoss of information

Solution Approach 1:

The patent segments the registration process from the imaging process. The reference device is tracked using a separate optical system rather than being imaged by the medical imaging modality. This segmentation allows automatic registration to proceed while keeping the medical images free of distracting registration device artifacts, preserving anatomical information clarity

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS11210780B2Automatic image registration of scans for image-guided surgery

Publication Date: 2021.12.28 BRAINLAB AG

AI summary

Provided is a method for determining a position of an imaged anatomical body part of a patient. The method includes acquiring patient image data describing a digital image of at least part of a reference device and the anatomical body part, acquiring reference device model data describing a model of at least one of at least one internal surface or at least one external surface of the reference device, determining, —based on the patient image data and the reference device model data, reference device image position data describing a relative position between the reference device and the anatomical body part, acquiring reference device tracking data describing a position of the reference device in the tracking reference system, and determining, based on the reference device image position data and the reference device tracking data, body part tracking data describing a position of the anatomical body part in the tracking reference system.