Recurrent Neural Network Head Pose Prediction for VR

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Solution Overview

Problem

Current head pose prediction methods in augmented and virtual reality systems, such as the constant acceleration model, suffer from inaccuracies due to assumptions about head kinematics, leading to significant positional and angular errors, which affect the rendering of virtual content and user experience.

Innovation Solution

A recurrent neural network (RNN) approach is employed for head pose prediction, utilizing long short-term memory (LSTM) units or gated recurrent units (GRUs) to learn from actual user data without fixed mathematical models, providing more accurate and robust predictions by accounting for individual head motion patterns and resilience to external influences.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If constant acceleration model is used for head pose prediction, then computational simplicity is maintained, but prediction accuracy deteriorates due to assumptions about head kinematics

Engineering Contradiction:
Improvecomputational simplicityVSAvoidprediction accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent replaces the mechanical constant acceleration model with a neural network-based predictive system. The neural network learns head pose patterns from historical sensor data without relying on fixed mathematical assumptions about head kinematics, thereby improving prediction accuracy while maintaining real-time performance through trained model inference.

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

Solution Approach 2:

The patent transforms the prediction approach by changing from fixed parameter-based mathematical modeling (constant acceleration) to adaptive parameter learning through neural networks. The system dynamically adjusts prediction parameters based on learned patterns from actual user head motion data, improving accuracy across varying motion conditions.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If recurrent neural network is used for head pose prediction, then prediction accuracy improves by learning from actual user data, but computational complexity increases

Engineering Contradiction:
Improveprediction accuracyVSAvoidcomputational complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by training the recurrent neural network offline before deployment. During actual use, the pre-trained model performs fast inference without requiring complex real-time training computations. This separates the computationally intensive learning phase from the real-time prediction phase, reducing operational complexity.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses a simplified version of the recurrent neural network architecture optimized for embedded deployment. By creating a lightweight copy of the full model suitable for resource-constrained devices, the system maintains high prediction accuracy while reducing computational complexity through model optimization techniques.

Inventive Principle:
Principle #26Copying

3Loss of time

If RNN predicts head pose at future time horizon, then rendering latency is reduced by preparing virtual content in advance, but prediction errors may increase due to larger time gap

Engineering Contradiction:
Improverendering latencyVSAvoidprediction error
Core Design Contradiction:
Loss of timeVSMeasurement precision

Solution Approach 1:

The patent uses preliminary action by predicting head pose at a future time horizon to enable advance preparation of virtual content rendering. The recurrent neural network learns temporal patterns in head motion, allowing it to accurately predict future positions even at extended time horizons, thus reducing rendering latency without proportionally increasing prediction errors.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS11662806B2Deep predictor recurrent neural network for head pose prediction
Publication Date: 2023.05.30 MAGIC LEAP INC
  • US11662806B2 patent drawing
  • US11662806B2 patent drawing
  • US11662806B2 patent drawing

AI summary

Systems and methods for predicting head pose for a rendering engine of an augmented or virtual reality device can include a recurrent neural network (RNN) that accepts a time series of head pose data and outputs a predicted head pose. The recurrent neural network can include one or more long short term memory (LSTM) units or gated recurrent units (GRUs). A fully connected (FC) layer can accept input from the RNN and output a 3 degree-of-freedom (DOF) head pose (e.g., angular orientation or spatial position) or a 6 DOF head pose (e.g., both angular orientation and spatial position). The rendering engine can use the predicted head pose to generate and display virtual content to the user at the time the user looks toward the position of the virtual content, which reduces system latency and improves user experience.