Eye Tracking via Fused Camera and Light Sensor Data
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Solution Overview
Problem
Existing eye tracking systems require high power and resource consumption to achieve high temporal resolution due to the need for capturing and processing images at a high frame rate.
Innovation Solution
The use of a device that combines camera images and light sensor data, with a lens directing light to both components, allowing for eye tracking with high temporal resolution using separate capture rates and a processor to fuse data for efficient eye tracking, potentially using a parameterized or machine learning-based approach.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If camera images are captured at a high frame rate to achieve high temporal resolution in eye tracking, then the temporal resolution is improved, but the power consumption and resource requirements increase significantly
Solution Approach 1:
The system segments the light collection function between two separate sensors: a camera for spatial information and a photodetector for temporal information. This segmentation allows each sensor to operate at optimized frame rates, with the photodetector capturing light at higher temporal resolution without requiring the camera to operate at the same high frame rate, thus reducing overall power consumption while maintaining high temporal resolution eye tracking capability.
2Device complexity
If a lens is used to split light to both camera and photodetector, then the device complexity is reduced through alignment, but the manufacturing precision requirements increase
Solution Approach 1:
The system merges the optical paths of the camera and photodetector by using a single lens to direct light to both sensors. This merging approach reduces the overall number of optical components and simplifies the optical design, while the alignment requirements are managed through the unified optical path shared by both sensors.
Solution Approach 2:
The lens acts as an intermediary optical element that splits and directs light to both the camera and photodetector. This intermediary component enables a single light source to serve dual purposes, reducing the need for separate optical paths and simplifying the overall system architecture while maintaining precise light distribution to both sensors.
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 method enables eye tracking with high temporal resolution while reducing power and resource consumption, allowing for more efficient tracking of eye characteristics without the need for high frame rate camera capture.
Implementation Method 1
The device includes a lens (e.g., a geometric phase lens or flat lens that uses polarization to redirect light in particular directions) positioned to direct a first portion of received light to the camera and a second portion of the received light to the light sensor
Implementation Method 2
camera images may be captured and used to identify multiple glint reflections on an eye surface
Implementation Method 3
The light sensor is configured to capture sensor data at a second capture rate that is faster than the first capture rate
Data Source
AI summary
Various implementations track an eye using both camera images and light sensor data, e.g., from a photosensitive surface or set of photodetectors. The camera need not capture images at a high capture rate since the light sensor data captured from the light sensor provides information about the eye during the time periods between camera frames. An eye tracking device may thus provide eye tracking with high temporal resolution using less power and resources and prior devices. The eye tracking device includes a lens (e.g., a diffractive optical element (DOE)) that splits received light onto the camera and light sensor. The camera and light sensor may be aligned, e.g., co-centered. Using such a lens to provide light to an aligned camera and light sensor facilitates tracking the eye characteristics by reducing the need for matching the data and/or accounting for multiple environmental light sources.