Monocular Vision Tracking Using Wireless Tracker and Calibration Board

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Solution Overview

Problem

Current monocular vision tracking technologies are costly and not suitable for ordinary pre-research or preliminary evaluations, requiring expensive hardware and being difficult to implement for general developers, with camera pose estimation accuracy reduced due to variable camera focal lengths on mobile platforms.

Innovation Solution

A method using a wireless tracker and a camera, such as a mobile phone with a VR head-mounted tracker, to acquire and convert camera poses through calibration board images, normalizing imaging model parameters and performing hand-eye calibration to synchronize camera and tracker poses, allowing for cost-effective construction of a monocular vision tracking database suitable for various scenarios.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If expensive devices such as 3D laser tracker, Vicon, or stereo camera are used to obtain camera true pose, then measurement precision is improved, but device cost increases significantly

Engineering Contradiction:
Improvecamera pose estimation accuracyVSAvoiddevice cost
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent uses a wireless tracker to capture motion information and a camera to capture calibration board images, creating a simplified copy of the expensive tracking system. The wireless tracker and camera combination reproduces the essential tracking function at a fraction of the cost of 3D laser trackers or Vicon systems, while maintaining sufficient accuracy for monocular vision tracking research

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The calibration board serves as an intermediary object that bridges the wireless tracker and camera. By capturing images of the calibration board at multiple positions and orientations, the system establishes a relationship between the wireless tracker's coordinate system and the camera's coordinate system, enabling pose conversion without requiring direct integration of expensive hardware

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If hardware time-synchronized acquisition method is used, then measurement precision is improved, but ease of operation deteriorates due to difficulty in implementation for general developers

Engineering Contradiction:
Improvesynchronization accuracyVSAvoidimplementation difficulty
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent replaces complex hardware time-synchronization mechanisms with a software-based post-processing approach. Instead of requiring hardware-level synchronization that is difficult to implement, the system uses recorded calibration board images and wireless tracker data to computationally establish the relationship between coordinate systems, making the synchronization process accessible to general developers through software algorithms rather than complex hardware configuration

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If camera imaging model is assumed unchanged, then ease of operation is improved, but measurement precision deteriorates due to variable focal length on mobile platforms

Engineering Contradiction:
Improvemodel assumption simplicityVSAvoidcamera pose true value estimation accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent incorporates feedback by capturing calibration board images at multiple positions and orientations, then using these images to compute and update the camera's intrinsic parameters and pose. This feedback loop allows the system to adapt to variable focal lengths and imaging model changes by continuously recalibrating based on actual captured images, maintaining accuracy despite mobile platform hardware variations

Inventive Principle:
Principle #23Feedback

Data Source

PatentUS11704833B2Monocular vision tracking method, apparatus and non-transitory computer-readable storage medium
Publication Date: 2023.07.18 BAIDU ONLINE NETWORK TECH (BEIJIBG) CO LTD
  • US11704833B2 patent drawing
  • US11704833B2 patent drawing
  • US11704833B2 patent drawing

AI summary

A monocular vision tracking method, apparatus, and a non-volatile computer-readable storage medium are provided. The method includes: acquiring a first camera pose by using a wireless tracker; capturing calibration board images by using a camera, and selecting a set of images from the captured calibration board images according to image sharpness and camera pose difference; calculating a second camera pose in the camera calibration algorithm according to the selected set of images; obtaining a conversion parameter between the first camera pose and the second camera pose; and converting a first capturing pose into a second capturing pose by means of the conversion parameter when a scenario is captured, wherein the first capturing pose is acquired by the wireless tracker and the second capturing pose corresponds to a pose of the camera.