See-Through Display Calibration for Eye Distance Alignment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing augmented reality (AR) and mixed reality (MR) glasses do not account for individual differences in eye distances during calibration, leading to inaccuracies in the fusion of virtual and real images.
Innovation Solution
A calibration method and system that uses an image sensing device to photograph virtual and real images, calculating projection homography matrices and intrinsic and extrinsic parameters to adjust the optical see-through display for accurate image fusion, accommodating varying eye distances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a predefined standard eye distance is used for calibration, then the calibration process is simple and quick, but the accuracy of virtual image fusion deteriorates when user eye distance differs from the standard
Solution Approach 1:
The patent changes the calibration parameter from a fixed standard eye distance to a variable parameter that adapts to each user's actual eye distance. The system captures images of a calibration pattern through the optical see-through display and calculates the actual eye distance based on the captured image coordinates, then adjusts calibration parameters accordingly to achieve accurate image fusion for each individual user.
2Measurement precision
If individual eye distance measurement and adaptation is implemented, then image fusion accuracy is improved, but the calibration process complexity increases
Solution Approach 1:
The system performs self-calibration by automatically capturing images of the calibration pattern, calculating the user's eye distance, and adjusting calibration parameters without requiring manual measurement or complex user intervention. The optical see-through display itself is used as the imaging medium, and the system autonomously completes the entire calibration process from image capture to parameter adjustment.
Solution Approach 2:
The patent introduces a calibration pattern as an intermediary object that facilitates the measurement of eye distance. This calibration pattern with known geometric features serves as a reference medium between the user's eyes and the system's measurement mechanism, enabling accurate calculation of eye distance through image coordinate analysis.
3Ease of manufacture
If manufacturing and assembly errors in optical elements are present, then production cost and ease of manufacture are improved, but the accuracy of virtual image fusion deteriorates
Solution Approach 1:
The system implements feedback-based calibration by capturing actual images through the optical see-through display, comparing the captured calibration pattern coordinates with expected coordinates, calculating deviations caused by manufacturing and assembly errors, and then adjusting calibration parameters to compensate for these errors, thereby achieving accurate image fusion despite manufacturing tolerances.
Data Source
AI summary
A calibration method for an optical see-through display includes the following. An image sensing device is fixed at a standard position of an eye of a user seeing the optical see-through display, and the image sensing device is configured to photograph a virtual image displayed by the optical see-through display and an image of a real object in an environment. Extrinsic parameters between the image sensing device and a virtual camera are calculated by using extrinsic parameters between the image sensing device and multiple calibration patterns of the real object as well as extrinsic parameters between the virtual camera and the multiple calibration patterns of the real object. A calibration system is also provided.