Headset External Camera Calibration Using Two 3D Controller Points

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Solution Overview

Problem

Existing calibration methods for external cameras of headsets in mixed reality capture are prone to failure due to environmental factors such as ambient light and joypad shape, making the process unreliable and difficult to execute accurately.

Innovation Solution

A method involving the use of a hand controller to determine two three-dimensional coordinates, allowing for rapid and accurate calibration of the camera pose by aligning visual marking information, independent of joypad shape or ambient light conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the PNP algorithm is used to calculate camera pose based on feature points extracted from images, then the calibration can be performed, but the process is easily influenced by ambient light, distance, and joypad shape, making calibration unreliable

Engineering Contradiction:
Improvecalibration reliabilityVSAvoidambient light influence
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent extracts only the essential calibration information (two three-dimensional coordinates) from the complex image processing task, eliminating the need for feature point extraction and PNP algorithm computation. This extraction approach removes the vulnerability to ambient light and joypad shape variations that plague traditional methods.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces visual marking information as an intermediary between the camera and the hand controller. This mediator provides a stable reference that is not affected by ambient light conditions or joypad shape variations, enabling reliable calibration through direct coordinate comparison rather than complex image analysis.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If the PNP algorithm with feature point extraction is used, then camera pose can be determined, but the calibration process becomes complex and difficult to operate accurately

Engineering Contradiction:
Improvecamera pose accuracyVSAvoidcalibration operation simplicity
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent segments the calibration process into two simple coordinate acquisition steps instead of requiring complex feature point extraction and algorithmic processing. This segmentation reduces operational complexity while maintaining precision by focusing only on essential measurements.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system uses the hand controller's built-in three-dimensional coordinate detection capability to perform calibration without requiring external feature objects or complex processing. The hand controller serves itself by providing both the coordinate data and the visual marking information needed for calibration.

Inventive Principle:
Principle #25Self-service

3Reliability

If traditional calibration methods are used, then camera pose can be calculated, but the process is time-consuming and requires complex user actions

Engineering Contradiction:
Improvecalibration accuracyVSAvoidcalibration time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies partial action by acquiring only the two essential three-dimensional coordinates needed for calibration, rather than performing complete feature point extraction and comprehensive pose calculation. This partial approach achieves sufficient accuracy while dramatically reducing calibration time.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent skips the time-consuming intermediate steps of feature point extraction, image processing, and PNP algorithm computation. By directly acquiring coordinates from the hand controller and comparing them with visual marking information, the system rushes through the calibration process efficiently while maintaining reliability.

Inventive Principle:
Principle #21Skipping (Rushing through)

Data Source

PatentEP4700706A1Method and apparatus for calibrating external camera of headset, device, and storage medium
Publication Date: 2026.02.25 BEIJING ZITIAO NETWORK TECH CO LTD
  • EP4700706A1 patent drawingFigure 1~2
  • EP4700706A1 patent drawingFigure 3~5
  • EP4700706A1 patent drawingFigure 6

AI summary

The present disclosure provides a method and an apparatus for calibrating an external camera of a headset, a device, and a storage medium. The method includes: obtaining first three-dimensional coordinates of a hand controller when a user puts the hand controller close to a camera, and determining a position of the camera according to the first three-dimensional coordinates, the camera being disposed fixedly and configured to shoot a behavior of the user; displaying an image shot by the camera, with visual marking information being displayed at a central position of the image; obtaining second three-dimensional coordinates of the hand controller when the hand controller is located at a position of the visual marking information in the image; and determining a pose of the camera according to the first three-dimensional coordinates and the second three-dimensional coordinates. According to the method, the user can rapidly complete a calibration of the camera by only needing to determine two points using the hand controller, and a calibration process is simple and easy to operate, and a calibration result is accurate.