Projected Fiducial Marker Alignment for Stable AR Registration
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Solution Overview
Problem
Existing augmented reality (AR) systems face challenges in achieving precise registration of virtual content in dynamic environments, as marker-based solutions require physical markers that degrade over time and markerless solutions suffer from sensor inaccuracies and environmental feature limitations, leading to registration errors that disrupt the AR experience.
Innovation Solution
A marker projection device that projects fiducial markers onto surfaces using depth information to ensure accurate registration, preserving geometrical proportions and adapting to environmental changes, allowing hybrid tracking and sensor recalibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If physical fiducial markers are placed in the environment for marker-based registration, then registration precision is improved, but maintenance requirements increase and reliability deteriorates due to marker degradation over time
Solution Approach 1:
The system creates virtual copies of physical fiducial markers by projecting marker patterns onto surfaces in the environment. These projected markers are generated digitally and displayed through the projection device, eliminating the need for physical marker materials while maintaining the geometric reference functionality. The virtual markers can be regenerated indefinitely without degradation.
Solution Approach 2:
The invention replaces the mechanical/physical marker system with an optical projection system. Instead of using physical objects that occupy space and can degrade, the system uses light projections to create virtual markers. This substitution eliminates wear and degradation issues while maintaining registration precision through optical reference patterns.
2Ease of manufacture
If markerless registration solutions are used to avoid physical markers, then maintenance requirements are reduced, but registration precision deteriorates due to sensor inaccuracies and environmental feature limitations
Solution Approach 1:
The system combines elements of both marker-based and markerless approaches by segmenting the registration process into two parts: projecting controlled reference patterns (marker-like) onto surfaces while using the projection device's own positioning sensors (markerless capability). This hybrid segmentation allows the system to benefit from both reference pattern geometry and flexible deployment.
Solution Approach 2:
The system performs preliminary action by projecting markers onto surfaces before the actual AR content is displayed. These pre-projected markers serve as reference patterns that the AR device can detect and use for registration. This preliminary marker projection establishes the geometric frame of reference needed for subsequent precise content placement.
3Ease of operation
If virtual content is registered using sensor data from markerless systems, then deployment simplicity is improved, but registration stability worsens due to drift over time
Solution Approach 1:
The system implements feedback by continuously monitoring the position and orientation of the projection device and adjusting the projected marker positions accordingly. The depth sensor provides real-time feedback about surface locations, and the system uses this information to maintain accurate marker placement. This closed-loop feedback compensates for drift and maintains registration stability over time.
Solution Approach 2:
The system performs preliminary action by establishing reference frames using projected markers before AR content is displayed. These pre-established geometric references provide a stable foundation that is less susceptible to drift compared to relying solely on continuous sensor data processing. The preliminary marker projection creates anchor points for subsequent stable registration.
Data Source
Figure 1a
Figure 1b
Figure 2a~2b
AI summary
In the disclosure, a marker projection device (100) for use in an augmented-reality system is described. The marker projection device (100) comprises a control unit that receives depth information data indicative of distances to surfaces (202A-C, 204, 206) in the environment of the marker projection device (100) and a marker image indicative of a visual appearance of a fiducial marker. Furthermore, the control unit is configured: to identify one or more potential projection surfaces (202A-C, 204, 206) in the environment using the depth information data; to select one (202B) of the one or more potential projection surfaces; to determine a projection angle (220A, 220B) for the selected projection surface; and to generate, using the depth information data and the projection angle for the selected projection surface, a projection image comprising an adapted marker image, wherein the control unit is configured to generate the adapted marker image by transforming the marker image such that geometrical proportions of the visual appearance of the fiducial marker are preserved when projected on the selected projection surface (202B). In addition, the marker projection device (100) comprises an optical projection unit that receives the projection image and is configured to generate a light projection according to the projection image.