Head-Mounted Eye Tracking With Lens Inverse Transform Correction
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Solution Overview
Problem
Prescription lenses in head-mounted displays interfere with eye tracking measurements by refracting light, affecting the accuracy of determining eye orientation in virtual reality applications.
Innovation Solution
An inverse transform is applied to images captured through vision correcting lenses using markers or user-input prescription settings to correct for refraction, allowing accurate eye tracking by transforming the images to resemble those without lenses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If vision correcting lenses are used in head-mounted displays, then users with prescription needs can use the device, but the lenses refract light and reduce eye tracking measurement accuracy
Solution Approach 1:
The patent applies an inverse transform algorithm that uses knowledge of the lens's refractive properties to mathematically correct the distorted eye images. The harmful refraction effect is converted into a correctable distortion pattern, allowing the system to recover accurate eye orientation data even when light is refracted by prescription lenses.
Solution Approach 2:
The system changes the parameter representation of eye images by applying an inverse optical transform that reverses the refraction effects. This mathematical transformation converts images distorted by lens refraction into corrected images that accurately represent the eye's true orientation, enabling precise eye tracking despite the presence of vision correcting lenses.
2Device complexity
If standard eye tracking is used without correction, then the system is simple to implement, but accuracy is reduced when lenses are present
Solution Approach 1:
The patent introduces an intermediary computational step - the inverse transform algorithm - that acts as a mediator between the raw distorted eye images and the final eye orientation measurements. This software-based intermediary corrects the optical distortions without requiring hardware modifications, maintaining relative system simplicity while significantly improving measurement accuracy.
3Productivity
If lens refraction is not corrected, then processing is faster and simpler, but eye tracking data is inaccurate for lens wearers
Solution Approach 1:
The system performs preliminary action by pre-calculating and storing inverse transform parameters based on known lens prescriptions. During actual eye tracking, these pre-computed transforms are applied to quickly correct images, reducing real-time processing overhead while maintaining high measurement accuracy for lens wearers.
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 precise eye tracking in head-mounted displays with prescription lenses by correcting for optical distortions, ensuring accurate interaction with VR, AR, and MR applications.
Implementation Method 1
Prescription lenses in head-mounted displays interfere with eye tracking measurements by refracting light
Data Source
AI summary
A computer implemented method includes receiving images of an eye through a vision correcting lens via a camera in a head mounted display device, obtaining an inverse transform corresponding to the vision correcting lens, applying the inverse transform to the received images to obtain uncorrected images of the eye, and performing eye tracking based on the uncorrected images of the eye.