Tracker Marker Identity Assignment via Visible-Infrared Spectrum Segmentation
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Solution Overview
Problem
In computer-assisted surgical procedures, trackers with a large number of markers face challenges in unambiguously identifying markers due to line-of-sight issues, leading to incorrect assignment of marker identities and imprecise tracking, which can result in improper surgical outcomes.
Innovation Solution
A method that uses a tracker with markers detectable in the infrared spectrum and a reference detectable in the visible light spectrum, where the pre-determined relationship between the markers and the reference is used to assign identities based on image data, allowing for accurate positioning and orientation without the need for active markers or complex communication devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If trackers use a large number of markers (6, 10 or more), then tracking coverage and reliability are improved, but marker identification ambiguity increases leading to incorrect fitting
Solution Approach 1:
The patent segments the marker identification problem into two independent parts: (1) detecting marker positions in the infrared spectrum, and (2) identifying marker identities through visible light spectrum imaging of the tracker body. This segmentation resolves the ambiguity by separating position detection from identity identification.
Solution Approach 2:
The patent introduces an intermediary element - the tracker body with visually detectable features - that mediates between the infrared markers and the identification system. The tracker body serves as a visible reference frame that links marker positions to their identities without requiring active components on the markers themselves.
2Measurement precision
If active markers with communication capabilities are used, then marker identification accuracy is improved, but manufacturing costs and device complexity increase
Solution Approach 1:
The patent extracts the identification functionality from the markers themselves and relocates it to the tracker body. Instead of each marker needing communication capabilities, the tracker body contains the visual features that enable identification, while markers simply provide infrared detectability.
Solution Approach 2:
The patent enables the use of inexpensive, passive, disposable markers without communication capabilities. The markers are simple infrared-reflective or infrared-emitting elements that can be replaced easily, while the reusable tracker body contains the identification features.
3Loss of information
If active markers with power sources are used, then unique identification capability is improved, but manufacturing costs and suitability for disposable use deteriorate
Solution Approach 1:
The patent extracts the power source and communication requirements from the markers and places them in the tracker body. The markers themselves remain passive, simple, and power-free, making them easy to manufacture and suitable for disposable use.
Solution Approach 2:
The patent uses a visual copy or representation of the tracker body in the visible light spectrum to convey identification information. Instead of complex active components in each marker, the system captures an image of the tracker body and uses image processing to identify marker identities based on their positions relative to visual features.
4Ease of manufacture
If passive reflective markers are used, then manufacturing simplicity and disposability are improved, but identification accuracy under line-of-sight limitations deteriorates
Solution Approach 1:
The patent adds another dimension - the visible light spectrum imaging of the tracker body - to the traditional infrared marker detection. This additional dimension provides contextual information about marker positions and identities that resolves ambiguities when some markers are not visible in the infrared spectrum.
Data Source
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AI summary
A method, computer program product, device, and tracking system for assigning marker identities to markers of a tracker are provided. The tracker comprises a reference detectable in a visible light spectrum, and the markers are detectable at least in an infrared light spectrum. The markers are arranged in a pre-determined relationship relative to the reference and the pre-determined relationship is indicative of the marker identities. A method implementation comprises receiving first image data of the markers captured in the infrared spectrum. The method further comprises receiving second image data of the reference captured in the visible light spectrum, wherein the first and second image data in some variants were captured under at least essentially the same viewing angle. The method also comprises determining the markers in the first image data and determining the reference in the second image data. The method further comprises assigning the marker identities to the markers determined in the first image data based on the reference determined in the second image data and the pre-determined relationship.