Head-Mounted Display Posture Correction via Sensor Fusion

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Solution Overview

Problem

Existing technologies face challenges in accurately detecting the posture and movements of a target object, particularly in head-mounted displays, which can lead to user discomfort and physical issues due to inconsistencies in detected values.

Innovation Solution

The system combines motion sensors, such as acceleration and gyro sensors, with image processing to accurately acquire posture data, using correction formulas and rotation correction techniques to minimize errors and ensure precise detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Difficulty of detecting and measuring

If motion sensors (acceleration and gyro sensors) are used to detect posture and movements, then the detection capability is improved, but measurement precision deteriorates due to accumulated errors and inconsistencies

Engineering Contradiction:
Improvedetection capabilityVSAvoidposture detection accuracy
Core Design Contradiction:
Difficulty of detecting and measuringVSMeasurement precision

Solution Approach 1:

The patent combines multiple detection methods (motion sensors, optical tracking of markers, and image processing) into a single integrated system. The motion sensors provide continuous tracking data while optical markers and image processing provide periodic reference measurements, and their results are fused to achieve both continuous operation and high precision posture detection.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system uses image processing results as feedback to correct and calibrate motion sensor measurements. By comparing the posture data from motion sensors with the more accurate but less frequent optical tracking data, the system continuously refines its measurements to maintain high precision over time.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If multiple sensors and correction techniques are combined to improve accuracy, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improveposture detection accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The image processing system serves multiple functions: it tracks optical markers for posture detection, validates motion sensor data, provides calibration reference points, and corrects measurement errors. This multi-functionality reduces the need for separate dedicated components for each function.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent introduces correction formulas and calibration procedures as intermediary processes that bridge the gap between motion sensor measurements and actual posture values. These intermediaries process and adjust the raw sensor data to eliminate systematic errors without requiring complete redesign of the sensing system.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Speed

If detected values are used to reflect user posture in real-time, then responsiveness is improved, but reliability deteriorates when detection errors occur causing user discomfort

Engineering Contradiction:
Improvereal-time responsivenessVSAvoiduser safety and comfort
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The system performs preliminary calibration and error correction using image processing data before the motion sensor measurements are used for critical posture determination. By pre-establishing correction parameters and validating the sensing system, the system ensures that real-time posture reflections are based on accurate baseline measurements.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements error detection and correction mechanisms that cushion against the impact of detection errors. When measurement inconsistencies are detected, the system uses pre-established correction formulas and alternative measurement sources to compensate, preventing error propagation that would cause user discomfort or safety issues.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach enables highly accurate and reliable posture detection, enhancing user experience by minimizing discomfort and physical risks associated with inaccuracies in virtual reality applications.

Implementation Method 1

a motion sensor including an acceleration sensor and a gyro sensor, and a communication mechanism... obtain rates of acceleration on predetermined three axes measured by the acceleration sensor and angle information representing an attitude of the target object...

Methodology Applied
Scientific EffectAcceleration sensor measurement: Accelerometer

Implementation Method 2

a motion sensor including an acceleration sensor and a gyro sensor... obtain angular velocity measured by the gyro sensor...

Methodology Applied
Scientific EffectGyro sensor measurement: Gyroscope

Data Source

PatentEP3343320B1Information processing apparatus, information processing system, and information processing method
Publication Date: 2021.06.23 SONY INTERACTIVE ENTERTAINMENT LLC
  • EP3343320B1 patent drawingFigure 1
  • EP3343320B1 patent drawingFigure 2
  • EP3343320B1 patent drawingFigure 3

AI summary

In an information processing apparatus, a posture data acquiring section acquires output values from a motion sensor of a head-mounted display (S10). Effective rates of acceleration are then obtained by correcting the output values based on correction formulas (S12). A posture is calculated in reference to the axes of the motion sensor based on the acquired rates of acceleration. Thereafter, the posture of the head-mounted display is calculated by performing rotation correction based on previously acquired angle errors, the calculated posture being output to an information processing section (S14, S16). A correction data updating section acquires posture information based on markers of the head-mounted display imaged in a captured image (S18), and updates correction data for use in acquiring the posture from the sensor output values through comparison with the marker-based posture information (Y in S20, S22).