Laser Feedback Eye-State Sensing With Integrated Optical Detection
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Solution Overview
Problem
Existing methods for ascertaining eye states in a defined spatial region are complex and space-consuming, particularly when using infrared light for detecting eye effects like red-eye or bright-pupil effects.
Innovation Solution
A method utilizing a scanning laser feedback interferometry sensor to emit a light beam into a defined spatial region, measure the power modulation of the light source based on reflected light from an eye, and use laser feedback interferometry to ascertain eye states, including attention direction and blink intervals, with optional integration or separation of a processing unit for efficient data processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a separate detector is used to detect reflected radiation for ascertaining eye states, then measurement precision is improved, but device complexity and space requirements increase
Solution Approach 1:
The patent combines the light source and detector into a single integrated sensor unit. The sensor both emits laser light and detects the reflected light from eyes, eliminating the need for separate detectors positioned elsewhere in the system. This merging reduces structural complexity while maintaining the capability to measure eye states through reflected radiation detection.
Solution Approach 2:
The integrated sensor performs multiple functions: it acts as both a light source for illumination and a detector for measuring reflected radiation. This multi-functional design reduces the overall number of components needed in the system, simplifying the structure while enabling eye state ascertainment through the same device that provides illumination.
2Difficulty of detecting and measuring
If infrared light is used to detect red-eye or bright-pupil effects, then eye state detection capability is improved, but the system becomes more space-consuming and complex
Solution Approach 1:
The patent integrates the infrared light source and detector into a single compact sensor unit, eliminating the need for separate infrared illumination devices and detectors that would require additional space. This integration maintains the infrared detection capability for red-eye and bright-pupil effects while reducing the overall system footprint.
Solution Approach 2:
The patent replaces complex mechanical infrared detection systems with an integrated optical sensor that combines light emission and detection functions. This substitution reduces mechanical complexity and space requirements while maintaining the ability to detect infrared reflected radiation from eyes for determining eye states.
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 a compact and simplified method to determine eye states, including attention levels and number of individuals, suitable for various environments, enhancing safety and statistical analysis.
Implementation Method 1
This scattered-back portion interferes with the incident laser beam, that is, with the laser beam propagating towards the eye. Using the so-called laser feedback interferometry, the emitted laser beam is superposed with the scattered-back radiation, so as to generate resulting radiation interference.
Data Source
AI summary
A method for ascertaining at least one eye state of at least one person situated in a defined spatial region. At least one light beam is directed, in a scanning manner, into the defined spatial region using a light source of a scanning laser feedback interferometry sensor. The defined spatial region has, in the horizontal direction, at least the dimension of a width of a head of the person. A modulation of the power of the light source of the laser feedback interferometry sensor is measured as a function of at least one light beam reflected back by at least one eye of the person situated in the defined spatial region. The at least one eye state of the at least one person situated in the defined spatial region is ascertained as a function of the modulation of the power of the light source, using a processing unit.