Stereo Infrared Gaze Detection for Head Movement
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Solution Overview
Problem
Conventional gaze detection systems are limited by a fixed camera-to-eye distance, making them unsuitable for situations with head movement, such as virtual reality simulators and desktop computing environments, and often require cumbersome head gear to accommodate dynamic measurements.
Innovation Solution
A system using two infra-red cameras and strobe lights to capture stereo image pairs, employing triangulation for precise eye location in three-dimensional space and edge-fitting algorithms to determine gaze direction without the need for user-worn equipment, allowing for minimal calibration and high-speed tracking of both eyes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single camera is used to detect gaze direction, then the system structure is simple, but the system cannot accommodate head movement and is limited to fixed camera-to-eye distance
Solution Approach 1:
The patent transitions from a single-camera 2D detection system to a dual-camera stereo vision system, adding spatial dimensionality. This enables 3D eye position reconstruction and gaze detection that accommodates head movements in multiple directions, resolving the limitation of fixed camera-to-eye distance while maintaining reasonable system complexity.
Solution Approach 2:
The dual-camera system serves multiple functions: it detects eye position in 3D space, determines gaze direction, and accommodates various head positions and distances without requiring headgear. This multi-functionality resolves the contradiction by making the system adaptable to different scenarios while using a relatively simple optical setup.
2Adaptability or versatility
If electronic or mechanical devices are used to dynamically measure camera-to-eye distance, then head movement can be accommodated, but head gear is required which limits usefulness
Solution Approach 1:
The patent replaces mechanical measurement devices (distance sensors, headgear) with an optical stereo vision system. The dual-camera setup uses triangulation and image processing to calculate eye position and gaze direction optically, eliminating the need for mechanical distance measurement devices and headgear, thereby improving user convenience while maintaining adaptability to head movements.
Solution Approach 2:
The patent introduces infrared illuminators and infrared-sensitive cameras as intermediaries to detect eye position indirectly through the red-eye effect. This intermediary approach allows distance and position measurement without physical contact or headgear, resolving the contradiction between adaptability and ease of operation.
3Measurement precision
If two-step approach with fixed camera is used, then eye location can be found using red-eye phenomenon, but the system is limited to fixed distance and cannot track both eyes simultaneously with high resolution
Solution Approach 1:
The patent divides the detection task between two specialized cameras: one optimized for detecting eye location using the red-eye effect, and another for capturing high-resolution images of both eyes simultaneously. This segmentation allows each camera to be optimized for its specific function while working together to achieve comprehensive gaze tracking with high precision and 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
Enables unobtrusive, high-accuracy gaze detection that can replace traditional pointers in computer control and improve virtual simulation systems, with minimal calibration requirements and no need for user-worn equipment, while accommodating varying distances and head movements.
Implementation Method 1
One method of quickly and accurately finding the eyes in an image is based on the 'red-eye' phenomenon, well known to users of flash cameras. Two sets of infrared illuminators are used, with one set spaced apart from the other. Two images (obtained in rapid succession) are subtracted, leaving the 'red-eye' reflections from the pupils
Implementation Method 2
A system using two infra-red cameras and strobe lights to capture stereo image pairs, employing triangulation for precise eye location in three-dimensional space
Data Source
AI summary
A system and method for gaze detection of an animate subject, typically a human. The subject's pupils are located in three dimensional space, using red-eye detection techniques and triangulation. Then, the gaze direction is determined based on the shape of the subject's irises.