Autoclavable LED Fiducial Assembly With Refraction-Corrected Tracking
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Solution Overview
Problem
Existing autoclavable LEDs for optical tracking in surgical settings suffer from significant metrological errors due to light refraction through exit windows, leading to unacceptable localization inaccuracies, and current solutions require complex manufacturing techniques to mitigate this issue.
Innovation Solution
An autoclavable fiducial marker assembly with a metallized coating to shield the peripheral edge of a window panel from light rays, combined with a tracking device that adjusts detected light ray positions based on calculated refraction deviations, using optical sensors and a processor to triangulate the location of the light source accurately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a window panel is used to enclose the LED in an autoclavable fiducial marker, then sterilization capability is achieved, but light refraction occurs causing localization inaccuracy
Solution Approach 1:
The patent applies this principle by using the refraction effect in reverse - instead of trying to eliminate refraction, the system pre-calculates refraction deviations for different angles and uses these calculations to correct the observed light ray positions. The harmful refraction is converted into a predictable, correctable phenomenon by creating a lookup table of refraction angles versus observation angles.
Solution Approach 2:
The patent implements feedback by using the observed light ray positions and comparing them against pre-calculated refraction models. The system iteratively adjusts the estimated LED position based on the difference between observed and expected refraction patterns, ultimately converging on the accurate three-dimensional location of the LED.
2Measurement precision
If complex manufacturing techniques are used to mitigate refraction, then localization accuracy improves, but manufacturing complexity and cost increase
Solution Approach 1:
The patent replaces mechanical/optical solutions (such as complex window geometries or special coatings) with a computational approach. Instead of modifying the physical structure to eliminate refraction, the system uses mathematical models and algorithms to calculate and correct for refraction effects, substituting a software-based solution for hardware complexity.
Solution Approach 2:
The patent changes the approach from modifying physical parameters (window shape, material properties) to adjusting computational parameters (refraction models, calculation algorithms). By changing from physical design parameters to computational correction parameters, the system achieves high accuracy without complex manufacturing.
3Ease of operation
If light rays pass through the exit window for optical tracking, then tracking function is enabled, but refraction causes computed location to differ from true location
Solution Approach 1:
The patent applies preliminary action by pre-calculating refraction deviations for a range of possible observation angles before the actual tracking occurs. These pre-computed refraction corrections are stored and readily applied during real-time tracking, eliminating the need for complex real-time calculations while maintaining high accuracy.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution reduces localization inaccuracy by compensating for light refraction, enabling precise optical tracking with simplified manufacturing processes and cost-effective fabrication.
Implementation Method 1
the window panel configured to refract a plurality of light rays emitted by the light emitting semiconductor die
Implementation Method 2
a metallized coating forming a hermetic seal at an interface of the window panel and the opaque housing, wherein the fiducial marker assembly is configured to shield a peripheral edge of the window panel from the plurality of light rays
Implementation Method 3
a tracking device comprising at least two optical sensors, each optical sensor configured to detect a position of a light ray of the plurality of light rays
Data Source
AI summary
An optical tracking system is provided. The optical tracking system comprises an autoclavable fiducial marker assembly including an opaque housing, a light source, a window panel configured to refract light rays from the light source therethrough, and a metallized coating forming a hermetic seal at an interface of the window panel and the opaque housing. The fiducial marker assembly is configured to shield a peripheral edge of the window panel from the light rays. The system further comprises a tracking device comprising at least two optical sensors configured to detect a position of a light ray emitted by the light source. The system further comprises a processor configured to receive the position of the light rays from the optical sensors, shift the position of each light ray based on a calculated refraction deviation, and triangulate the location of the light source based on the shifted position of each light ray.