AR Radar Head Pose Localization Drift Correction
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Solution Overview
Problem
Augmented reality devices face challenges in maintaining the stationary position of rendered objects relative to real-world objects as the user moves, due to measurement unit drift over time, which affects the accuracy of pose estimation and object placement.
Innovation Solution
The use of a radar system that generates radar maps and fingerprints to determine pose estimates, combined with an inertial measurement unit and a measurement unit filter, to correct for drift and accurately position rendered objects relative to real-world objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a measurement unit (IMU) is used to track movement of the augmented reality device, then the position of rendered objects can be adjusted in real-time, but measurement drift occurs over time causing loss of measurement precision
Solution Approach 1:
The system implements feedback by continuously comparing IMU-based pose estimates with radar-based pose estimates. The radar system periodically provides accurate reference measurements that are used to detect and correct drift in the IMU measurements, ensuring long-term measurement precision while maintaining real-time responsiveness
Solution Approach 2:
The radar system acts as an intermediary reference system that mediates between the fast but drifting IMU measurements and the accurate but slower radar measurements. By fusing these two measurement sources, the system achieves both real-time tracking capability and long-term accuracy
2Measurement precision
If radar maps are generated and processed to determine pose estimates, then measurement precision is improved, but device complexity increases due to additional processing requirements
Solution Approach 1:
The system applies partial action by using radar measurements selectively rather than continuously. Radar maps are generated and processed only periodically or when drift correction is needed, rather than at every frame rate, reducing processing complexity while maintaining measurement precision when it matters most
Solution Approach 2:
The processing is segmented into distinct functional modules: radar signal processing, map generation, fingerprint extraction, pose estimation, and drift correction. This segmentation allows each module to be optimized independently and facilitates efficient implementation of the complex overall system
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 ensures that rendered objects remain stationary relative to real-world objects, even as the user moves, by accurately adjusting for measurement unit drift, thereby enhancing the stability and accuracy of augmented reality experiences.
Implementation Method 1
The radar system includes at least a first radar device that has a first radar transmitter secured to the frame and transmitting a radio wave at first and second times in a slow domain and a first radar receiver secured to the frame and detecting the radio waves after the radio waves are reflected from a surface
Implementation Method 2
The measurement unit may be secured to the frame and detects first and second measurement values at the first and second times in the slow domain, each measurement value being indicative of a position and movement of the measurement unit
Data Source
AI summary
An augmented reality device has a radar system that generates radar maps of locations of real world objects. An inertial measurement unit detects measurement values such as acceleration, gravitational force and inclination ranges. The values from the measurement unit drift over time. The radar maps are processed to determine fingerprints and the fingerprints are combined with the values from the measurement unit to store a pose estimate. Pose estimates at different times are compared to determine drift of the measurement unit. A measurement unit filter is adjusted to correct for the drift.