Wearable Display Frame Timing Based on Retinal Velocity
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Solution Overview
Problem
Head-mounted devices experience image blurring and undesirable color artifacts due to rapid eye movements, as existing eye-tracking systems struggle to accurately determine gaze direction and retinal velocity, leading to inadequate adjustment of display frame times.
Innovation Solution
A wearable device dynamically tracks the cornea and gaze direction of a user's eyes, calculating retinal velocity to adjust display frame times based on eye movement, using low-intensity light emitters and cameras to capture glint patterns and determine eye position and orientation, allowing for precise rendering of virtual scenes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the display frame time is kept constant, then the device operation is simple, but image blurring and color artifacts occur due to rapid eye movements
Solution Approach 1:
The display frame time is dynamically adjusted based on real-time eye movement detection. When rapid eye movements are detected, the frame time is shortened to prevent blurring; when eye movements are slow, the frame time is extended for better image quality. This dynamic adaptation resolves the contradiction between maintaining simple operation and preventing image degradation.
Solution Approach 2:
The system uses eye-tracking feedback to continuously monitor gaze direction and retinal velocity, then adjusts display parameters accordingly. This closed-loop feedback mechanism allows the system to automatically optimize image quality without requiring complex manual control, resolving the contradiction between reliability and device complexity.
2Measurement precision
If high-intensity light sources are used to track eye position, then gaze direction can be determined, but specular reflections (glints) are generated that interfere with accurate tracking
Solution Approach 1:
The system changes the intensity parameter of light sources dynamically. Low-intensity lights are used during normal operation to avoid glints, while high-intensity lights are activated only when additional gaze direction information is needed. This parameter modulation allows the system to obtain accurate measurements without generating harmful specular reflections during continuous operation.
Solution Approach 2:
High-intensity light sources are activated periodically or intermittently rather than continuously. This periodic activation provides sufficient data for gaze tracking while minimizing the generation of specular reflections, thus resolving the contradiction between measurement precision and harmful factors.
3Reliability
If the frame time is shortened to track rapid eye movements, then image blurring is reduced, but the energy consumption increases
Solution Approach 1:
The frame time is dynamically adjusted based on detected eye movement velocity. During periods of rapid eye movement, frame time is shortened to maintain image stability. During periods of slow or stable gaze, frame time is extended to reduce energy consumption. This dynamic adjustment resolves the contradiction between reliability and energy usage.
Solution Approach 2:
The system changes the time parameter of display frames based on real-time eye movement analysis. By adapting frame duration to actual physiological needs rather than using a fixed high rate, the system maintains image stability only when necessary, thereby reducing overall energy consumption.
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
This solution effectively reduces image blurring and artifacts by dynamically adjusting display frame times according to retinal velocity, providing a more stable and accurate virtual reality experience by accounting for rapid eye movements.
Implementation Method 1
An infrared light source illuminating the eye of a wearer at a relatively high intensity may generate specular reflections off the wearer's cornea, also called 'glints'.
Data Source
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AI summary
In some examples, techniques and architectures for operating a device that may be wearable, such as a head-mounted device, may be used for virtual reality applications. A processor of the device may operate by dynamically tracking the cornea, and thus the gaze direction, of a user's eyes. By tracking the gaze direction, retinal velocity of a display image projected onto the retina, measured in the retina coordinate frame may be computed. Display times of image frames viewable by the user may be modified based on the retinal velocity.