Eye Tracking Arrangement Using Laser Doppler Velocimetry
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Solution Overview
Problem
Existing eye tracking systems are complex, energy-intensive, and have limited temporal resolution, making them inefficient for precise and cost-effective gaze direction tracking.
Innovation Solution
An eye tracking arrangement combining a camera and a laser velocimeter using laser Doppler velocimetry to detect eye velocity and determine absolute eye positions, allowing for high-resolution and energy-efficient tracking of gaze movements without moving components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If camera-based systems or electrical sensors are used for eye tracking, then eye position information can be acquired, but the system complexity and energy consumption increase
Solution Approach 1:
The patent replaces complex mechanical scanning systems with a stationary laser velocimeter that uses laser Doppler velocimetry to measure eye velocity. This substitution eliminates moving parts while maintaining measurement capability, directly resolving the contradiction between measurement precision and device complexity
Solution Approach 2:
The patent changes the measurement parameter from direct eye position (using cameras) to eye velocity (using laser Doppler effect). By measuring velocity and integrating it to obtain position, the system achieves accurate eye tracking with simpler, stationary components, resolving the complexity issue
2Measurement precision
If high temporal resolution eye tracking is achieved using traditional systems, then eye movement can be tracked precisely, but energy consumption increases
Solution Approach 1:
The patent uses periodic laser beam modulation at high frequencies to achieve high temporal resolution velocity measurements. The laser is modulated periodically to scan across the eye surface, capturing velocity data at high rates while consuming less energy than continuous high-speed camera operation
Solution Approach 2:
The patent replaces energy-intensive high-speed camera systems with a laser-based velocity measurement system. The laser velocimeter achieves high temporal resolution through optical interference measurements rather than mechanical scanning, significantly reducing energy consumption while maintaining precision
3Measurement precision
If scanned laser systems with micromirrors are used, then eye tracking can be performed, but the system complexity and cost increase
Solution Approach 1:
The patent extracts and eliminates the micromirror scanning component from the laser system. Instead of using a scanned laser with moving mirrors, the invention uses a stationary laser velocimeter that measures eye velocity directly through laser Doppler velocimetry, maintaining tracking capability while reducing complexity
Solution Approach 2:
The patent introduces laser Doppler velocimetry as an intermediary measurement method between the laser source and the eye. This intermediary technique allows velocity measurement without direct mechanical scanning, enabling accurate eye tracking with a simpler, stationary laser system
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 provides high accuracy and temporal resolution in eye movement tracking with low energy consumption, enabling flexible and reliable applications, particularly suitable for smart glasses with extended battery life and user convenience.
Implementation Method 1
the laser velocimeter is configured to detect the eye velocity with a second scanning rate using laser Doppler velocimetry
Implementation Method 2
The laser velocimeter is arranged to detect an eye velocity using laser Doppler velocimetry
Implementation Method 3
determine a Doppler shift between the irradiated laser beam and the backscattered portion based on a laser feedback interferometry
Data Source
AI summary
The invention relates to an eye tracking arrangement that includes a camera configured to capture images of an eye at a first scanning rate, a laser velocimeter configured to capture an eye velocity of a movement of the eye by laser Doppler velocimetry at a second scanning rate and a control device configured to determine an absolute eye position based on the images, and track a gaze direction of the eye based on the absolute eye position and the eye velocity.