EMG Facial Expression Detection for Obscured VR Views

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Solution Overview

Problem

Existing systems for detecting facial expressions in virtual reality environments face challenges due to obscured facial views, leading to reduced accuracy in facial expression detection.

Innovation Solution

The use of electromyography (EMG) signals from unipolar electrodes placed on a facemask to detect facial expressions, with preprocessing techniques like common mode removal and normalization, combined with various classification methods such as LDA, QDA, and neural networks to accurately categorize and identify facial expressions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If video feed algorithms are used to detect facial expressions, then the system can perform facial recognition, but the detection accuracy deteriorates when the face is obscured by VR hardware

Engineering Contradiction:
Improvefacial expression detection accuracyVSAvoidface obscuration by VR hardware
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces optical-based video feed facial recognition with an electromyography (EMG) based detection system. EMG electrodes detect electrical signals from facial muscles directly, bypassing the need for visual observation of facial features. This substitution of detection mechanism eliminates the problem of face obscuration by VR hardware, as muscle electrical signals can be detected through skin contact regardless of visual blocking.

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

Solution Approach 2:

The patent introduces EMG electrodes as an intermediary detection medium between the facial muscles and the detection system. These electrodes contact the skin and capture electrical signals from underlying muscles, serving as a mediator that allows detection of facial expressions without requiring direct visual access to facial features. This intermediary approach enables accurate detection even when VR hardware obscures the face.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If EMG signals are processed with preprocessing and classification methods, then facial expression detection accuracy improves, but the computational complexity increases

Engineering Contradiction:
Improvefacial expression detection accuracyVSAvoidsignal processing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the EMG signal processing into distinct functional modules: preprocessing (noise removal, filtering), feature extraction (identifying relevant signal characteristics), and classification (categorizing expressions). This segmentation allows each module to be optimized independently and facilitates implementation on resource-constrained mobile devices by breaking down the complex processing task into manageable stages.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies preprocessing operations (such as noise removal and signal filtering) before classification to simplify the signal and remove irrelevant information. This preliminary action reduces the complexity of subsequent classification tasks by providing cleaner, more standardized input data, thereby lowering the overall computational burden while maintaining or improving detection accuracy.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If multiple classification methods are applied to EMG signals, then facial expression categorization accuracy improves, but the processing time increases

Engineering Contradiction:
Improvefacial expression categorization accuracyVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent employs multiple classification methods but applies them in a hierarchical or selective manner rather than simultaneously processing all methods for every input. This partial action approach uses simpler classifiers for routine cases and reserves more computationally intensive methods for ambiguous or critical detections, thereby achieving high accuracy while controlling processing time within acceptable limits for real-time application.

Inventive Principle:
Principle #16Partial or excessive action

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

Enables accurate and efficient detection of facial expressions with low latency on mobile devices, even when the face is partially obscured, improving user interaction in VR environments.

Implementation Method 1

EMG signals can be obtained from one or more electrodes placed on a face of the user... EMG refers to electromyography, which measures the electrical impulses of muscles

Methodology Applied
Scientific EffectElectromyography:

Data Source

PatentUS11328533B1System, method and apparatus for detecting facial expression for motion capture
Publication Date: 2022.05.10 GENESIS GROWTH TECH LLC
  • US11328533B1 patent drawing
  • US11328533B1 patent drawing
  • US11328533B1 patent drawing

AI summary

A system, method and apparatus for detecting facial expressions according to EMG signals.