Optical Motion Tracking in Brain Imaging via Pattern Projection
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Solution Overview
Problem
Current motion tracking systems in medical imaging, particularly in MRI and PET scanners, face challenges with head motion artifacts that reduce image quality and require complex subject preparation, often failing to achieve high temporal and spatial resolution simultaneously.
Innovation Solution
A method and apparatus using a light projector and camera to project and detect pattern sequences on a subject's surface, enabling markerless motion tracking with adaptive pattern determination for improved accuracy and reduced preparation requirements, optimizing pattern projection for relevant subregions and excluding sensitive areas like the eyes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If markers are attached to the subject's head for motion tracking, then motion tracking capability is improved, but subject preparation complexity and potential errors increase
Solution Approach 1:
The patent extracts the motion tracking functionality from external markers and integrates it directly into the imaging system through optical projection. Patterns are projected onto the subject's head surface and tracked without requiring physical attachment of markers, thereby eliminating preparation complexity while maintaining tracking precision.
Solution Approach 2:
The patent introduces projected light patterns as an intermediary between the imaging system and the subject's head motion. These optical patterns serve as virtual markers that can be tracked without physical contact, resolving the contradiction between tracking accuracy and preparation simplicity.
2Measurement precision
If high resolution patterns are projected for improved motion tracking precision, then measurement precision is improved, but memory requirements and data processing load increase
Solution Approach 1:
The patent applies local quality by projecting high-resolution patterns only in specific regions of interest on the subject's head rather than uniformly across the entire surface. This localized approach maintains tracking precision where needed while reducing overall data volume and memory requirements.
Solution Approach 2:
The patent uses partial action by selectively projecting patterns on relevant subregions and excluding sensitive areas like the eyes. This partial coverage strategy provides sufficient motion tracking data without the excessive memory and processing demands of full-surface high-resolution projection.
3Measurement precision
If pattern projection covers the entire head surface for comprehensive motion tracking, then measurement completeness is improved, but patient safety is compromised due to eye illumination
Solution Approach 1:
The patent implements local quality by differentiating treatment across the head surface: high-resolution pattern projection is applied to safe regions while sensitive areas like the eyes are excluded or treated with reduced intensity. This spatially differentiated approach maintains tracking completeness without compromising patient safety.
Solution Approach 2:
The patent converts the potential harm of eye illumination into a benefit by using the exclusion of sensitive areas as a design feature. The motion tracking system is optimized to derive sufficient data from safe regions, and the avoided eye illumination becomes a safety advantage rather than a limitation.
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
Enables submillimeter motion tracking, improved image quality, reduced memory requirements, and enhanced tracking speed and accuracy, while ensuring patient safety by adjusting patterns to avoid eye illumination and optimizing for surface regions with significant curvature.
Implementation Method 1
providing a light projector and a first camera and projecting a first pattern sequence (S1) onto a surface region of the subject with the light projector
Implementation Method 2
detecting the projected first pattern sequence (S1') with the first camera
Data Source
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AI summary
Disclosed is apparatus and method for motion tracking of a subject in medical brain imaging. The method comprises providing a light projector and a first camera; projecting a first pattern sequence (S1) onto a surface region of the subject with the light projector through first optical fibers, wherein the subject is positioned in a scanner borehole of a medical scanner, the first pattern sequence comprising a first primary pattern (P1,1) and/or a first secondary pattern (P1,2); detecting the projected first pattern sequence (S1') with the first camera; and determining motion tracking parameters based on the detected first pattern sequence (S1').