Self-Tracked Controllers for Full-Body Pose Beyond HMD Visibility

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Solution Overview

Problem

Existing AR/VR systems struggle to estimate a user's full body pose accurately due to HMD cameras being unable to capture the lower body parts, leading to incomplete pose estimation and negatively impacting user experience.

Innovation Solution

Utilizing self-tracking controllers with integrated cameras and IMUs to perform SLAM for self-localization, capturing images of body parts not visible to HMD cameras, and combining these with HMD camera data to determine a full body pose using inverse-kinematic optimizers and muscular-skeletal models.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If HMD cameras are used to estimate body pose, then the system structure is simple, but the lower body parts cannot be captured resulting in incomplete pose estimation

Engineering Contradiction:
Improvebody pose estimation accuracyVSAvoidsystem structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system divides the body tracking function into multiple segments: HMD cameras capture upper body pose, while controllers capture hand poses and lower body poses. This segmentation allows each component to focus on specific body regions, achieving complete full-body tracking without requiring a single complex camera system to capture everything.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Controllers serve as intermediary devices between the user and the tracking system. They capture images of body parts not visible to HMD cameras and provide additional pose information, acting as a mediator that bridges the gap between limited HMD camera coverage and complete body pose estimation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Loss of information

If controllers with cameras are introduced to capture lower body parts, then complete body pose estimation is achieved, but the device complexity increases

Engineering Contradiction:
Improvebody part visibilityVSAvoidsystem configuration
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

Controllers perform multiple functions: they track hand poses through IMU sensors, capture images of lower body parts through integrated cameras, and provide visual feedback to users. This multi-functionality reduces the need for separate dedicated devices for each tracking function, thereby managing complexity while achieving comprehensive body pose estimation.

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

Solution Approach 2:

The system merges the tracking functionality into existing controllers that users already hold. By combining hand tracking capabilities with lower body capture and visual feedback functions in a single device, the system avoids adding separate complex hardware components while achieving complete body pose estimation.

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If multiple data sources are integrated for full body pose estimation, then measurement accuracy improves, but data processing complexity increases

Engineering Contradiction:
Improvefull body pose accuracyVSAvoiddata processing system
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The data processing system segments pose estimation into distinct modules: upper body pose estimation from HMD camera images, hand pose estimation from controller IMU data, and lower body pose estimation from controller camera images. Each module processes specific data types independently before integration, reducing overall processing complexity while maintaining high accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system employs feedback mechanisms where the processed pose information is used to adjust and refine the estimation algorithms. Visual feedback from controllers and iterative optimization of pose estimates based on multiple data sources enable accurate full-body tracking while managing processing complexity through adaptive refinement rather than exhaustive computation.

Inventive Principle:
Principle #23Feedback

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

Accurately estimates the full body pose of users, even when parts are not visible to HMD cameras, enhancing user experience by providing complete body avatars and ensuring privacy through local data processing.

Implementation Method 1

a head pose determined using an inertial measurement unit associated with the headset

Methodology Applied
Scientific EffectInertial measurement: Accelerometer

Implementation Method 2

the pose of the controller may be determined using simultaneous localization and mapping (SLAM) for self-localization

Methodology Applied
Scientific EffectSimultaneous localization and mapping:

Data Source

PatentEP4359892B1Body pose estimation using self-tracked controllers
Publication Date: 2025.08.13 META PLATFORMS TECHNOLOGIES LLC
  • EP4359892B1 patent drawingFigure 1A
  • EP4359892B1 patent drawingFigure 1B
  • EP4359892B1 patent drawingFigure 2A

AI summary

In one embodiment, a computing system may determine a pose of a controller held by a user based on sensor data captured by the controller. The system may determine positions of a first set of keypoints associated with a first portion of a body of the user based on images captured by the controller cameras and (2) the controller pose. The system may determine a pose of a headset worn by the user based on sensor data captured by the headset. The system may determine positions of a second set of keypoints associated with a second portion of the body of the user based on images captured by the headset cameras and (2) the pose of the headset. The system may determine a full body pose of the user based at least on the positions of the first set and the second set of keypoints.