Reciprocal Optical Tracking for Occlusion-Resilient Surgical Pose Sensing
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Solution Overview
Problem
Conventional optical tracking systems in surgical environments are susceptible to line-of-sight obstruction, sun reflection, and require costly, bulky components, leading to inaccurate and ineffective surgical procedures.
Innovation Solution
A dual optical sensor module system with adaptive lighting and quality threshold checks, enabling robust optical tracking by alternating light sources and ensuring image quality meets predefined standards, and integrating with a central processor for real-time control of surgical instruments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional optical tracking systems use reflected light from markers or fiducials, then the system can track position and orientation data, but the line of sight can be obscured by surgical objects or surgeons blocking the view
Solution Approach 1:
The patent introduces an intermediary light source that directly illuminates the fiducial marker, eliminating the need for external light reflection. This direct illumination approach ensures that the fiducial can be tracked reliably even when the line of sight between the camera and fiducial is partially obstructed by surgical objects or surgeons, as the light source is integrated with the fiducial itself
Solution Approach 2:
The patent replaces the passive optical reflection mechanism with an active light emission mechanism. Instead of relying on external light sources and reflective markers, the system uses fiducials with integrated light sources that actively emit light, substituting the mechanical/optical reflection system with an active illumination system that is less susceptible to line-of-sight obstructions
2Reliability
If fiducials are equipped with sensors to sense light output, then tracking can be improved, but sun reflection can blind the sensor and obscure the tracking
Solution Approach 1:
The patent changes the wavelength parameter of the light source to infrared, which is not visible to the human eye and less affected by sunlight interference. The fiducial contains an infrared light source that emits infrared light, and the camera is configured to detect infrared wavelengths, thereby eliminating the blinding effect of sun reflection while maintaining tracking accuracy
Solution Approach 2:
The patent implements periodic modulation of the infrared light source, causing it to emit light in pulses or at specific frequencies. This periodic action allows the camera to distinguish the fiducial's light from ambient infrared radiation and sunlight, enabling reliable tracking even in bright surgical environments by synchronizing the detection with the modulation frequency
3Measurement precision
If optical tracking systems use expensive and bulky components, then measurement precision can be maintained, but storage capacity increases and surgeon movement is inhibited
Solution Approach 1:
The patent segments the tracking system into separate functional components: small fiducials with integrated light sources attached to surgical instruments, and a separate camera system for detection. This segmentation allows the fiducials to be miniaturized and attached to tools without adding bulk to the surgical instruments, while the camera system can be positioned optimally for detection without interfering with surgical access
Solution Approach 2:
The patent makes the camera system multi-functional by configuring it to detect infrared wavelengths in addition to visible light, allowing a single camera to serve both surgical visualization and fiducial tracking functions. This universality eliminates the need for separate dedicated tracking cameras, reducing overall system complexity and bulk while maintaining measurement precision
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
Enhances surgical precision and accuracy by maintaining effective optical tracking despite environmental interference, reducing contamination risks, and optimizing surgical workflow efficiency.
Implementation Method 1
a fiducial is configured with a sensor to sense light (e.g., in the infrared range) output by a light source
Data Source
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Figure 3A~3C
AI summary
Methods, non-transitory computer readable media, tracker devices, central processor devices, and optical tracking systems that facilitate improved optical tracking in surgical environments are disclosed. With this technology, background images are captured within an acquisition sequence. The background images are used to analyze the quality of current images that are captured in the acquisition sequence and to determine an angular position of optical sensor modules of optical tracker devices with respect to light sources coupled to a reference frame that can be integral with an opposing one of the tracker devices. Using multiple tracking devices facilitates a reciprocal angular position determination that is more accurate and can withstand occlusion of an optical sensor module. This technology generates alerts when fiducials are obscured at the tracker device and facilitates improved accuracy with respect to pose data used by surgical applications for automated manipulation of surgical tools and surgical visualization.