Optical Tracking via Coordinate Transformation for Surgical Precision
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Solution Overview
Problem
Conventional optical tracking systems for surgery face challenges in accurately tracking patients or surgical instruments during procedures, particularly when patients move or change posture, due to difficulties in marker attachment, reduced accuracy, and high costs associated with manufacturing specialized templates.
Innovation Solution
An optical tracking system comprising a reference marker unit, a shape measurement unit, and a tracking sensor unit, which measures and senses three-dimensional shapes and positions to define a coordinate system relative to a reference marker, allowing for real-time tracking and re-registration without the need for direct attachment of a dynamic reference base to the patient.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a dynamic reference base (DRB) is strictly fixed to the patient for accurate tracking, then measurement precision is improved, but device complexity and ease of operation deteriorate due to the need for strict fixation and re-registration procedures
Solution Approach 1:
The patent extracts the reference marker from the patient's body and places it on the surgical table instead. This eliminates the need for strict fixation to the patient while maintaining tracking accuracy, as the marker remains stationary in the surgical field without requiring invasive attachment methods
Solution Approach 2:
The patent introduces a coordinate transformation mechanism that acts as an intermediary between the surgical instrument coordinate system and the patient anatomy coordinate system. This allows accurate tracking to be maintained even when the reference marker is not directly attached to the patient, resolving the contradiction between tracking precision and operational ease
2Measurement precision
If a dynamic reference base (DRB) is strictly fixed to the patient, then measurement precision is improved, but loss of time increases due to re-registration requirements when patient posture changes
Solution Approach 1:
By removing the reference marker from direct attachment to the patient and placing it on the surgical table, the system eliminates the need for re-registration when patient posture changes. The marker remains stationary while the patient can move freely, preventing time loss from repeated registration procedures
Solution Approach 2:
The patent creates a dynamic system where the reference marker is decoupled from the patient's body movements. The coordinate transformation mechanism dynamically adapts to patient posture changes without requiring manual re-registration, maintaining tracking accuracy while reducing time loss
3Measurement precision
If markers are implanted in bone or attached via bite templates, then measurement precision is improved, but object-affected harmful factors increase due to patient discomfort and side effects
Solution Approach 1:
The patent extracts the reference marker application from the patient's body entirely, placing it on the surgical table instead. This eliminates all harmful factors associated with bone implantation or bite template attachment, including pain, infection risk, and patient discomfort, while maintaining tracking precision through coordinate transformation
Solution Approach 2:
The patent creates a coordinate system copy that represents the patient's anatomy without requiring physical markers on the patient. The reference marker on the surgical table serves as a proxy, and coordinate transformations map this proxy to the actual patient anatomy, eliminating harmful physical attachments while preserving measurement accuracy
Data Source
AI summary
An optical tracking system may comprise a reference marker unit stationarily disposed relative to a patient, a shape measurement unit configured to measure the three-dimensional shape of a specified part of the patient corresponding to a three-dimensional image, a tracking sensor unit configured to sense the reference marker unit and the shape measurement unit, and a processing unit. The processing unit may acquire a coordinate transformation relationship between the reference marker unit and the tracking sensor unit and a coordinate transformation relationship between the shape measurement unit and the tracking sensor unit based on a sensing result of the tracking sensor unit, acquire a coordinate transformation relationship between the specified part of the patient and the shape measurement unit based on a measurement result of the shape measurement unit, and define a coordinate system of the patient relative to the reference marker unit from the acquired coordinate transformation relationships.