Retinal Reflection Gaze Tracking for Low-Power Target Detection
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Solution Overview
Problem
Existing eye-tracking techniques using near-infrared (nIR) illuminators and CMOS cameras are not feasible in low-power applications due to high power consumption when frame rate is reduced, necessitating a more efficient method for gaze direction detection.
Innovation Solution
A low-power eye-tracking system using a photodiode and optical alignment with a target area, where gaze direction is detected based on spectral reflections, allowing for power savings by activating high-power CMOS sensors only when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If nIR illuminators and CMOS cameras are used for eye tracking, then accurate gaze direction detection is achieved, but power consumption becomes too high for low-power applications
Solution Approach 1:
The eye tracking system is segmented into two functional modes: a low-power mode using a photodiode for detecting spectral reflections at specific angles, and a high-power mode using CMOS cameras for comprehensive gaze tracking. The system segments the detection task based on operational requirements, using the photodiode for power-saving operations and CMOS cameras only when full accuracy is needed.
Solution Approach 2:
The patent applies partial action by using a photodiode with narrow co-axial angle sensitivity to detect only the specific spectral reflections corresponding to target area gaze directions, rather than using a full CMOS camera array to capture all possible gaze directions. This partial detection approach provides sufficient accuracy for triggering actions while consuming significantly less power.
2Use of energy by moving object
If frame rate is reduced to save power, then power consumption decreases, but tracking accuracy and responsiveness deteriorate
Solution Approach 1:
The patent replaces the mechanical imaging system (CMOS camera capturing images at reduced frame rates) with an optical detection system (photodiode detecting spectral reflections). This substitution allows continuous or high-frequency detection without the power consumption penalties of the CMOS camera, maintaining tracking accuracy while enabling power savings through reduced illuminator activity.
3Productivity
If CMOS imager and nIR LEDs are kept on continuously for tracking, then gaze direction is always available, but power consumption becomes infeasible for low-power applications
Solution Approach 1:
The system implements periodic action by activating the nIR illuminator and photodiode only when gaze direction needs to be assessed for triggering actions, rather than maintaining continuous operation. The illuminator can be activated periodically or on-demand, and the photodiode continuously monitors spectral reflections at low power, providing continuous tracking capability only when needed while maintaining low power consumption during idle periods.
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 accurate gaze direction detection with reduced power consumption, facilitating actions like initiating XR experiences or notifications based on glances at specific target areas.
Implementation Method 1
receiving sensor data from a sensor, wherein a direction of sensing by the sensor and a direction from the eye to a target area are approximately aligned, determining a reflective property of the reflection based on the sensor data
Implementation Method 2
The detector may be a near infrared (nIR) transceiver sensitive to spectral reflections at narrow co-axial angles. The detector may use low-power hardware (e.g., a photodiode paired with a lens)
Data Source
AI summary
Various implementations disclosed herein include devices, systems, and methods that initiate an action based on a detected gaze direction oriented towards a target area (e.g., a hot corner/zone). For example, an example process may include producing a reflection by directing light towards an eye using an illuminator, receiving sensor data from a sensor, wherein a direction of sensing by the sensor (e.g., the optical axis of the camera) and a direction from the eye to a target area are approximately aligned, determining a reflective property (e.g., a spectral property) of the reflection based on the sensor data, detecting that a gaze direction of the eye is approximately oriented towards the target area (e.g., a hot zone/spot) based on the reflective property, and initiating an action based on detecting that the gaze direction is approximately oriented towards the target area.