Virtual Image Display Calibration Using Natural Scene Features
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Solution Overview
Problem
Conventional virtual image display systems require complex and cumbersome processes for extrinsic parameter calibration, necessitating the use of an ArUco marking board and multiple recalibrations, which are inefficient and labor-intensive.
Innovation Solution
A virtual image display system utilizing multiple cameras and a head-mounted display (HMD) for real-time image capturing and calibration, where the HMD calculates extrinsic parameters based on captured image information, displays error information, and allows users to interactively adjust positions to optimize calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the conventional ArUco marking board method is used for extrinsic parameter calibration, then the calibration can be performed, but the operation complexity and time consumption increase significantly
Solution Approach 1:
The patent extracts the calibration target from a specialized ArUco marking board to natural features in the environment (buildings, objects, landscapes). The system captures images of these natural targets and extracts feature points directly from the image content, eliminating the need for physical calibration boards and their associated setup complexity.
Solution Approach 2:
The calibration system can use any visible structure or object in the environment as a calibration target, not requiring specialized equipment. The same camera system used for normal operation is also used for calibration, and any scene with sufficient feature points can serve as a calibration target, making the system universally applicable without specialized tools.
2Measurement precision
If multiple cameras are used for calibration, then the extrinsic parameter calculation becomes more accurate, but the calibration process becomes more complex and time-consuming
Solution Approach 1:
The system performs feature point extraction and matching in advance during the calibration process, and pre-calculates projection relationships between multiple cameras. The extrinsic parameters are computed once based on these preliminary feature correspondences, avoiding iterative adjustments and reducing total calibration time while maintaining accuracy.
Solution Approach 2:
The patent uses image copying and feature point correspondence between multiple camera views. By identifying and matching the same physical features across different camera images, the system establishes geometric relationships without requiring physical movement or repeated measurements, significantly reducing calibration time.
3Adaptability or versatility
If the ArUco marking board is reset and photographed again for recalibration, then the calibration can be updated, but the process complexity and execution time increase
Solution Approach 1:
The calibration system is dynamic and can be performed at any time during system operation. Users can capture images of new calibration targets, and the system automatically processes these images to update extrinsic parameters. The calibration process adapts to different scenes and targets without requiring reset procedures or specialized recalibration modes.
Solution Approach 2:
The system performs automatic feature point extraction, matching, and extrinsic parameter calculation without requiring manual intervention for board positioning or complex操作流程. The calibration process is self-contained, using the camera system itself to capture and process calibration images, eliminating the need for external calibration boards and manual setup procedures.
Data Source
AI summary
A virtual image display system and an operation method thereof are provided. The operation method of the virtual image display system includes: using a plurality of cameras to perform image capturing action on a target portion of a user and obtain a plurality of image information; using the cameras to obtain a plurality of position information corresponding to the target portion according to the image information; using a head-mounted display (HMD) to receive the position information, calculate an extrinsic parameter according to the position information, and establish a plurality of re-projection image information according to the extrinsic parameter and the position information; using the HMD to obtain a plurality of error information according to a prediction image information and the re-projection image information; and using the HMD to display each error information and calibrate the extrinsic parameter to obtain a calibrated extrinsic parameter according to the error information.