Gaze Tracking Illuminators with Wavelength Separation
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Solution Overview
Problem
Conventional gaze-tracking systems for head-mounted display apparatuses face optical design constraints, requiring precise calibration due to variable user-eye distances and interference from spectacles, which complicates accurate gaze direction detection.
Innovation Solution
A gaze-tracking system with multiple illuminators emitting light of different wavelengths, combined with a camera and optical filters, allows for robust and efficient gaze direction tracking by filtering out unwanted reflections and accommodating movement, without being limited to a specific optical design or arrangement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the imaging device is arranged close to the user's eyes for proper imaging, then the imaging quality is improved, but the device complexity increases due to integration constraints within the head-mounted display apparatus
Solution Approach 1:
The patent combines the imaging device with the display optics by integrating the camera and illuminators within the head-mounted display apparatus framework. The imaging device is positioned to share optical paths and structural support with the display components, merging multiple functions into a unified integrated structure that reduces overall device complexity while maintaining close proximity to the user's eyes for high-quality imaging.
2Adaptability or versatility
If the head-mounted display apparatus moves during use, then the adaptability to user movement is improved, but the measurement precision of gaze direction deteriorates due to variable user-eye distances
Solution Approach 1:
The patent employs dynamic focusing capabilities where the imaging device can adjust its focal plane to accommodate varying distances between the user's eyes and the apparatus. The system dynamically adapts to movement by adjusting focus and recalibrating the optical paths in real-time, maintaining measurement precision despite changes in user-eye distance caused by apparatus movement.
Solution Approach 2:
The system implements feedback mechanisms that continuously monitor the position and orientation of the head-mounted display apparatus relative to the user's eyes. This feedback is used to dynamically adjust the imaging parameters, illuminator positioning, and optical calibration to compensate for movement, thereby maintaining accurate gaze direction detection despite variable distances.
3Ease of operation
If spectacles are worn by the user, then the comfort and usability are improved, but the reliability of gaze tracking deteriorates due to reflections from spectacle lenses
Solution Approach 1:
The patent extracts and separates the specular reflections from spectacle lenses from the gaze tracking signal. By using multiple illuminators at different wavelengths and positions, the system can identify and isolate reflections caused by spectacles, then exclude these extracted reflection signals from the gaze direction calculation, maintaining reliable tracking even when spectacles are worn.
Solution Approach 2:
The system applies local quality differentiation by using illuminators with different wavelengths and spatial arrangements to create distinct reflection patterns. The imaging device captures these differentiated patterns, allowing the system to locally identify and distinguish between reflections from the eye cornea and reflections from spectacle lenses based on their unique optical characteristics.
4Reliability
If multiple illuminators emitting different wavelengths are used, then the reliability of gaze tracking with spectacles is improved, but the device complexity increases due to additional optical components
Solution Approach 1:
The patent implements multi-functionality by designing the illuminators to serve dual purposes: they provide structural illumination for the display system while simultaneously enabling gaze tracking through their reflected light patterns. The same optical components are used for both display and tracking functions, reducing overall device complexity despite the need for multiple wavelengths and illuminators.
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 and reliable detection of gaze direction, even with spectacles, by using structured light pulses and optical filters to distinguish and focus reflections from multiple wavelengths, ensuring precise tracking regardless of head-mounted display movement.
Implementation Method 1
a plurality of illuminators (102) for emitting light pulses to illuminate a user's eye
Implementation Method 2
at least one lens (104) positioned on an optical path of reflections of the light pulses from the user's eye
Implementation Method 3
at least one camera (106) for capturing an image of the reflections of the light pulses
Implementation Method 4
The plurality of optical filters are divided into at least a first group and a second group, optical filters of the first group being configured to substantially allow a first range of wavelengths to pass through, while optical filters of the second group being configured to substantially allow a second range of wavelengths to pass through
Data Source
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AI summary
Disclosed is a gaze-tracking system for use in a head-mounted display apparatus, and a method of tracking a user's gaze, via such a gaze- tracking system. The gaze-tracking system comprises a plurality of illuminators for emitting light pulses to illuminate a user's eye when the head-mounted display apparatus is worn by the user, the illuminators comprising at least a first illuminator and a second illuminator; at least one lens positioned on an optical path of reflections of the light pulses from the user's eye, the at least one lens having no chromatic-aberration correction; at least one camera for capturing an image of the reflections of the light pulses; and a processor coupled with illuminators and the at least one camera, the processor being configured to control operations of the illuminators and the at least one camera, and to process the captured image to detect a gaze direction of the user.