Speckle Pattern Eye Tracking for Low-Power Precision
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Solution Overview
Problem
Existing eye-gaze tracking technologies are costly, complex, and lack accuracy in detecting small eye movements, particularly due to the reliance on multiple light sources and cameras, which also consume high power.
Innovation Solution
The method employs speckle patterns formed by diffuse and specular reflections of a light beam off the eye, using a single light source and detector to track eye movements with high precision, leveraging optical flow algorithms to detect micron-scale movements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple light sources and cameras are used for eye-gaze tracking, then measurement precision may be improved, but device complexity and power consumption increase
Solution Approach 1:
The patent combines multiple light sources into a single light source that generates speckle patterns, and integrates the detection function into a single detector. This merging approach maintains measurement precision while reducing device complexity by eliminating the need for multiple separate light sources and cameras.
Solution Approach 2:
The patent changes the physical state and properties of light by using speckle patterns - a specific optical phenomenon where coherent light scattered from a rough surface creates an interference pattern. This parameter change in light behavior enables accurate eye movement detection with a single light source and detector, resolving the contradiction between precision and complexity.
2Measurement precision
If multiple light sources and cameras are used for eye-gaze tracking, then measurement precision may be improved, but power consumption increases
Solution Approach 1:
The patent merges multiple power-consuming components (multiple light sources and cameras) into a single light source and single detector system. This consolidation maintains the measurement precision needed for eye movement detection while significantly reducing the total power consumption of the system.
Solution Approach 2:
The speckle pattern itself provides the measurement information without requiring additional active components. The interference pattern naturally encodes eye movement data, allowing the system to achieve high precision with minimal power consumption by utilizing the self-organizing properties of scattered coherent light.
3Measurement precision
If classical Purkinje imaging methods are used, then measurement precision is achieved, but cost and device complexity increase
Solution Approach 1:
The patent extracts only the essential measurement function from complex Purkinje imaging systems. By using speckle patterns, the invention isolates the core capability of detecting eye movements while removing unnecessary complexity, resulting in a simpler system that maintains measurement precision.
Solution Approach 2:
The patent replaces complex mechanical optical systems (multiple mirrors, lenses, and cameras required for Purkinje imaging) with a simpler system based on speckle pattern analysis. This substitution uses the optical interference phenomenon to achieve the same measurement precision with fewer mechanical components, reducing both complexity and cost.
4Measurement precision
If high frame rate detection is used to track fast eye movements, then measurement precision is improved, but computational requirements and power consumption increase
Solution Approach 1:
The speckle pattern naturally encodes motion information through its interference structure. By analyzing the temporal changes in the speckle pattern at high frame rates, the system can track fast eye movements with high precision while using computationally efficient algorithms that exploit the self-organizing properties of the speckle field, reducing the computational burden compared to traditional image processing methods.
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
This approach provides accurate, low-power, and cost-effective eye-gaze tracking that is robust to sensor location, capable of detecting small eye movements with reduced computational requirements.
Implementation Method 1
The eye may reflect a portion of the light beam
Implementation Method 2
detecting a plurality of speckle patterns formed at a detector by the portion of the light beam reflected by the eye
Data Source
Figure 1(a)~1(d)
Figure 2
Figure 3
AI summary
A method of tracking movement of an eye of a user includes directing a light beam at the eye. The eye may reflect a portion of the light beam. The method further includes detecting a plurality of speckle patterns formed at a detector by the portion of the light beam reflected by the eye. The plurality of speckle patterns may be detected at a predetermined frame rate. The method further includes tracking movement of the eye by tracking the plurality of speckle patterns from frame to frame.