Eye-Tracking Camera Field-of-View Shift Control
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Solution Overview
Problem
Near-eye displays for VR/AR applications often have eye-tracking cameras that are not optimally positioned due to variations in user facial features and interpupillary distances, leading to suboptimal or disabled eye-tracking functionality.
Innovation Solution
An eye-tracking camera system with a focusing element and an image sensor, where the image sensor can be laterally translated relative to the focusing element using an actuator, allowing the camera to adjust its position within the image circle to center the user's eye image, thereby correcting deviations and ensuring optimal positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the eye-tracking camera is fixed in a single position, then the device structure is simple and cost-effective, but the camera cannot be optimally positioned for users with different facial features and interpupillary distances
Solution Approach 1:
The patent implements a dynamic positioning mechanism where the image sensor can be laterally translated relative to the focusing element using an actuator. This allows the camera to adapt its field of view to different users' eye positions while maintaining a relatively simple overall structure. The dynamic adjustment resolves the contradiction by enabling adaptability without requiring a completely complex reconfigurable system.
Solution Approach 2:
The patent separates the image sensor from the focusing element, allowing independent positioning of each component. This segmentation enables the image sensor to be laterally translated to adjust the field of view while the focusing element remains relatively stable. The segmentation resolves the contradiction by allowing precise positioning adjustment without making the entire camera system complex.
2Device complexity
If the image sensor is positioned at the edge of the image circle, then the device structure is simplified, but perspective projection distortion is introduced
Solution Approach 1:
Instead of fixing the image sensor at the edge of the image circle, the patent allows dynamic lateral translation of the image sensor relative to the focusing element. This dynamic positioning enables the system to maintain optimal positioning (centered in the image circle) while keeping the optical path structure relatively simple. The actuator-driven adjustment resolves the contradiction by eliminating the need for complex optical path design while maintaining image quality.
3Measurement precision
If the eye-tracking camera uses a fixed field of view, then the system is simpler to control, but it cannot track eye movements accurately for users with varying eye positions
Solution Approach 1:
The patent implements a dynamic field-of-view adjustment mechanism where the image sensor can be laterally translated to track eye movements. The controller receives eye-tracking data and actuates the image sensor to follow the eye's position, maintaining accurate tracking while keeping the control system relatively simple. This resolves the contradiction by enabling precise eye-tracking without requiring a complex multi-component adjustment mechanism.
Solution Approach 2:
The patent employs a feedback loop where the controller continuously receives eye-position information and adjusts the image sensor position accordingly. This feedback mechanism enables accurate eye-tracking by dynamically adjusting the field of view based on real-time eye position data. The feedback principle resolves the contradiction by providing a systematic way to maintain measurement precision without excessive device complexity.
4Adaptability or versatility
If multiple eye-tracking cameras are used to cover different eye positions, then user coverage is improved, but the device complexity and cost increase significantly
Solution Approach 1:
Instead of using multiple fixed cameras, the patent employs a single eye-tracking camera with a dynamically adjustable field of view. The image sensor can be laterally translated to follow the user's eye position, allowing one camera to cover the same range that would otherwise require multiple cameras. This dynamic adjustment resolves the contradiction by providing comprehensive user coverage while maintaining a simple single-camera system.
Solution Approach 2:
The patent makes a single eye-tracking camera universal by enabling it to adapt to different users and eye positions through lateral translation of the image sensor. This multi-functional capability allows one camera to perform the work of multiple fixed cameras, resolving the contradiction by achieving comprehensive coverage without the complexity and cost of a multi-camera system.
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A~3C
AI summary
An imaging device includes a focusing element, an image sensor, and an actuator configured to translate at least one of the image sensor and the focusing element relative to each other. A controller of the imaging device is configured to use the image sensor to capture an image frame including at least a portion of the image of the object, determine a current position of the image of the object in the image frame, determine a deviation of the current position from a target position of the image of the object in the image frame, and operate the actuator to reduce the deviation. In this manner, the image of the object may be brought to a center of a captured image frame. Such an imaging device may be used as a self-aligning eye-tracking camera in a near-eye display.