Camera Sensor Segmentation for AR Positional Tracking
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Solution Overview
Problem
Existing AR and VR camera configurations are not optimized for both Augmented Reality preview and positional tracking, particularly failing to balance motion blur and signal-to-noise ratio, leading to inferior performance in fast motion and low illumination conditions.
Innovation Solution
A method and apparatus that decouple image exposure times for AR preview and positional tracking, using an inertial measurement unit (IMU) to determine exposure periods for reducing motion blur while maintaining sufficient signal-to-noise ratio, employing High Dynamic Range imaging techniques and alternating or parallel transmission of images for effective tracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single camera configuration is used for both AR preview and positional tracking, then device complexity is reduced, but tracking precision deteriorates under fast motion conditions due to motion blur
Solution Approach 1:
The patent segments the camera's pixel array into multiple groups, where each group can be independently configured with different exposure times. Specifically, a first group of pixels uses a first exposure time optimized for positional tracking (shorter exposure to reduce motion blur), while a second group of pixels uses a second exposure time optimized for AR preview (longer exposure for better image quality in low light). This segmentation allows simultaneous optimization of both functions without requiring multiple physical cameras.
Solution Approach 2:
The patent applies local quality by assigning different exposure characteristics to different regions (pixel groups) of the same camera sensor. The first group of pixels has localized exposure parameters tailored for tracking precision, while the second group has localized exposure parameters tailored for preview quality. This enables each region to perform its specific function optimally without compromising the other.
2Reliability
If exposure time is increased to improve signal-to-noise ratio in low illumination, then image quality improves, but motion blur increases degrading tracking accuracy
Solution Approach 1:
The patent divides the pixel array into distinct groups with different exposure time configurations. The first group of pixels uses a shorter exposure time that minimizes motion blur for accurate tracking, while the second group uses a longer exposure time that maximizes signal-to-noise ratio for quality preview images. This segmentation resolves the contradiction by allowing both exposure strategies to coexist in the same camera device.
Solution Approach 2:
The patent dynamically assigns different exposure times to different pixel groups based on their intended function. The system can adaptively control which pixel group captures data for tracking versus preview, allowing real-time optimization of the trade-off between motion blur and signal-to-noise ratio without requiring manual configuration changes.
3Measurement precision
If exposure time is decreased to reduce motion blur for fast motion tracking, then tracking reliability improves, but signal-to-noise ratio deteriorates reducing image quality
Solution Approach 1:
The patent segments the camera sensor into multiple pixel groups with independently controllable exposure times. The first group uses a short exposure time optimized for tracking reliability under fast motion, while the second group uses a long exposure time optimized for signal-to-noise ratio in preview images. This allows the system to simultaneously achieve both tracking reliability and image quality without compromise.
Solution Approach 2:
The patent makes a single camera device universal by enabling it to perform both positional tracking and AR preview functions with optimized performance. Through multi-group pixel configuration with different exposure times, the camera becomes multi-functional, handling both the high-speed tracking requirement and the high-quality preview requirement within a single device.
Data Source
AI summary
Methods, apparatuses, and systems are described for positional tracking (PT) in Augmented Reality (AR) applications. The method may include creating different images for AR preview and PT applications. In some cases, the PT information utilizes key point information. The AR preview and the PT images may be generated simultaneously using time division, space division, split timing, or any combination thereof. This may result in PT with significantly less motion blur. Accordingly, the PT will be more robust, and there will be more good frames available for key components of a PT algorithm (i.e., using visual PT to calibrate the biases of an inertial measurement unit). Thus, the methods and apparatus of the present disclosure may enable more effective management of the trade-off between motion-blur, noise and resolution for PT.