Composite Illumination Source for Gaze Tracking
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Solution Overview
Problem
Existing gaze tracking systems require high hardware complexity and multiple illumination sources to achieve accurate and robust gaze estimation, limiting their portability and usability due to constraints on field of view and variability in bright pupil responses.
Innovation Solution
A minimal hardware complexity apparatus design using a composite illumination source with a reduced number of illumination sources, capable of capturing low-resolution images that include sufficient detail for gaze tracking, by ensuring a bright pupil response at the beginning of the operating range and creating a Purkinje image distinguishable at the end of the range, with an illumination controller and signal processing controller for image transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple illumination sources are used to ensure accurate and robust gaze estimation, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple illumination sources into a composite illumination source that functions as a single unit. This composite source integrates the functionality of multiple individual sources while reducing overall system complexity, allowing the system to maintain measurement precision through the composite illumination pattern without requiring separate control circuitry for each source
Solution Approach 2:
The composite illumination source serves multiple functions simultaneously: it creates the bright pupil response needed for pupil detection, generates detectable corneal glint patterns, and provides adequate illumination across the field of view. This multi-functionality eliminates the need for separate illumination sources for different gaze tracking functions
2Measurement precision
If high resolution sensors are used to capture sufficient eye detail, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The illumination sources are positioned and configured in advance to pre-structure the light patterns that will reflect off eye components. The composite illumination source is designed with specific positioning and size characteristics that pre-condition the reflected light to create easily distinguishable patterns, allowing standard sensors to achieve high measurement precision without requiring complex high-resolution sensor systems
3Device complexity
If on-axis illumination is used to simplify the apparatus, then device complexity is reduced, but adaptability decreases due to constrained field of view
Solution Approach 1:
The composite illumination source is designed with specific local characteristics: it is positioned close to the optical axis to simplify the apparatus structure, yet its size and positioning are optimized to create adequate illumination across the entire field of view. The illumination pattern has different local properties - concentrated near the axis for structural simplicity and distributed across the FOV for adaptability
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 enables effective gaze tracking within a defined operating range with reduced hardware complexity, maintaining image quality and resolution to distinguish key eye components, such as the pupil and corneal glint, while minimizing the number of illumination sources and sensor resolution required.
Implementation Method 1
at least one optical system capable of capturing radiation in a wavelength range produced by a composite illumination source
Implementation Method 2
The bright-pupil response under active-IR illumination is the infrared equivalent of the more widely known red-eye effect from photography, occurring when the light source used to illuminate the scene is positioned close to the camera's optical axis, so as to produce a retro-reflection from the retina
Implementation Method 3
the composite illumination source size is such that it creates a Purkinje image on a user's eye capable of being distinguished by the optical system
Data Source
AI summary
A system and an apparatus are provided, for gaze tracking within a defined operating range. The apparatus includes at least one optical system, which capable of capturing radiation in a wavelength range produced by a composite illumination source. The apparatus also includes at least one set of illumination sources creating the composite illumination source, wherein: at least one of the illumination sources is positioned relative to the optical system such that it ensures a user bright pupil response at the beginning of the apparatus operating range; and the composite illumination source size is such that it creates a Purkinje image on a user's eye capable of being distinguished by the optical system at the end of the apparatus operating range. The apparatus also includes an illumination controller for activating and deactivating the at least one composite illumination source, and a signal processing controller for transmitting generated images from the at least one optical system.