Retro-reflective Pupil Tracking Array with High-Speed Camera
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Solution Overview
Problem
Conventional retro-reflectivity systems for pupil detection are limited by the speed of conventional sensors and processors, which allow for less than 60 frames per second, making it difficult to accurately track pupils, especially when the subject is moving quickly, and require specialized optical filters for simultaneous on-axis and off-axis image collection.
Innovation Solution
An optical array system using a high-speed camera with a gaming motion sensor and LED arrays for illuminating pupils, allowing for high-frame-rate image capture and processing to isolate pupil information without the need for specialized filters, enabling pupil tracking and gaze detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional sensors and processors are used for pupil detection, then the system structure is simple and cost-effective, but the frame rate is limited to less than 60 frames per second, making it difficult to accurately track pupils when the subject is moving quickly
Solution Approach 1:
The patent replaces conventional sensors and processors with a high-speed camera system that captures images at higher frame rates. This substitution enables accurate pupil tracking during quick movements by increasing the temporal resolution of pupil detection, directly resolving the contradiction between frame rate and system complexity.
2Measurement precision
If on-axis and off-axis images are collected simultaneously using specialized optical filters, then pupil detection accuracy is improved for moving subjects, but the device complexity and cost increase
Solution Approach 1:
The patent employs periodic alternation between on-axis and off-axis image capture modes. The high-speed camera sequentially captures images with different illumination configurations at such high speed that both types of images are obtained without requiring simultaneous capture. This periodic action eliminates the need for complex optical filters while maintaining measurement precision.
Solution Approach 2:
The system performs preliminary calibration to determine the specific on-axis and off-axis illumination angles for each subject. This pre-established knowledge allows the high-speed camera to capture the required image types in sequence without needing complex real-time optical filtering, thereby improving measurement precision without increasing device complexity.
3Productivity
If the frame rate is increased to capture moving pupils accurately, then pupil tracking performance improves, but the requirement for specialized optical filters and simultaneous image collection increases device complexity
Solution Approach 1:
The patent substitutes complex optical filtering systems with a high-speed camera system that achieves the required image capture speed through increased temporal resolution. The camera captures sequential on-axis and off-axis images so rapidly that the system effectively operates in real-time without requiring specialized optical filters, thus improving productivity while reducing device complexity.
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 fast and accurate detection of pupil presence, location, and movement, allowing for effective pupil tracking and gaze detection, even in dynamic situations, by capturing and processing images at a higher frame rate than conventional systems, and implementing the system as a Human Interface Device.
Implementation Method 1
Retro reflectivity is a property of the human eye, meaning that when a light source is shone into the eye, a majority of the incident light will be reflected back in the direction from which it came.
Implementation Method 2
An LED array comprising at least one on-axis LED and at least one off-axis LED, for illuminating pupils of a user within an active region
Implementation Method 3
a high-speed camera with a gaming motion sensor, for capturing images of the pupils illuminated by the LED array
Data Source
AI summary
An optical array system for performing pupil tracking using retro-reflectivity includes: an LED array including at least one on-axis LED and at least one off-axis LED, for illuminating pupils of a user within an active region; a high-speed camera with a gaming motion sensor, for capturing images of the pupils illuminated by the LED array; and a processor, coupled to the high-speed camera, for receiving the captured images and performing processing algorithms on them to isolate pupil information and thereby determine pupil presence and location within the active region.