Gesture Identification Using EMG Signal Segmentation and N-gram Models

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Solution Overview

Problem

Existing gesture identification systems employing wearable electronic devices are not robust against variations in use parameters, requiring elaborate training procedures and struggling to accurately identify gestures performed by generic users or under different conditions, such as changes in device position, orientation, or user-specific factors like sweat and skin conditions.

Innovation Solution

A method that includes segmenting sensor signals into data windows, assigning window classes based on Root Mean Square (RMS) values, and determining gesture probabilities using n-gram transition models, allowing for accurate gesture identification without extensive user calibration, even under varying conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional gesture identification systems use elaborate training procedures to improve accuracy, then measurement precision improves, but device complexity and loss of time increase

Engineering Contradiction:
Improvegesture identification accuracyVSAvoidtraining procedure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The gesture identification process is segmented into distinct phases: signal acquisition, feature extraction (RMS, zero-crossing rate, waveform length), and classification. This segmentation allows the system to process gestures efficiently without requiring comprehensive training procedures, as each phase operates independently with well-defined functions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system changes the approach from training-based parameter adaptation to using fixed, pre-determined parameters for gesture identification. By relying on intrinsic signal properties (RMS, zero-crossing rate, waveform length) that naturally vary with gesture type, the system achieves accurate identification without requiring users to undergo training procedures that would increase device complexity.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If traditional systems perform extensive calibration to improve reliability, then gesture identification reliability improves, but loss of time increases

Engineering Contradiction:
Improvegesture identification reliabilityVSAvoidcalibration time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary action by pre-processing the EMG signals through filtering and feature extraction before classification. The signal is filtered to remove noise and artifacts, and features are extracted in advance, allowing the classification stage to operate efficiently without requiring time-consuming calibration procedures. This preliminary processing ensures reliable gesture identification from the first use.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system employs self-service by automatically adapting to different users and gestures through intrinsic signal analysis. The algorithm automatically identifies gesture patterns based on the electrical properties of the user's muscles without requiring manual calibration. The system serves itself by continuously learning from the signal characteristics, eliminating the need for time-consuming calibration sessions.

Inventive Principle:
Principle #25Self-service

3Measurement precision

If systems use multiple sensors and complex processing to improve measurement precision, then gesture detection accuracy improves, but use of energy increases

Engineering Contradiction:
Improvegesture detection accuracyVSAvoidprocessor energy consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The system extracts only the essential features from the EMG signals: RMS (root mean square), zero-crossing rate, and waveform length. By taking out only these critical features rather than processing the entire raw signal, the system achieves accurate gesture detection while minimizing computational load and energy consumption. This selective extraction approach maintains measurement precision without the energy cost of comprehensive signal processing.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The system applies partial action by using a limited set of processing operations focused on the most discriminative features. Rather than performing exhaustive analysis of all signal characteristics, the system applies just enough processing (filtering, RMS calculation, zero-crossing detection, waveform length measurement) to achieve reliable gesture identification, thereby reducing energy consumption while maintaining adequate measurement precision.

Inventive Principle:
Principle #16Partial or excessive action

4Adaptability or versatility

If systems require user-specific calibration to improve adaptability, then adaptability to individual users improves, but ease of operation deteriorates

Engineering Contradiction:
Improveuser-specific gesture recognitionVSAvoidsetup simplicity
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The system achieves universality by designing a gesture recognition algorithm that works across different users without requiring user-specific calibration. The EMG signal processing and classification approach is universally applicable to all users, as it relies on fundamental physiological properties of muscle electrical activity that are consistent across individuals. This multi-functional approach allows the same system to accurately recognize gestures from any user immediately upon use.

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

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 reliable and accurate gesture identification for generic users across different use conditions without the need for elaborate training procedures, improving user experience and reducing computational resources, thus extending battery life and simplifying the device's infrastructure.

Implementation Method 1

electromyography sensors providing gesture control

Methodology Applied
Scientific EffectElectromyography:

Data Source

PatentUS10684692B2Systems, devices, and methods for gesture identification
Publication Date: 2020.06.16 META PLATFORMS TECHNOLOGIES LLC
  • US10684692B2 patent drawing
  • US10684692B2 patent drawing
  • US10684692B2 patent drawing

AI summary

Systems, devices, and methods adapt established concepts from natural language processing for use in gesture identification algorithms. A gesture identification system includes sensors, a processor, and a non-transitory processor-readable memory that stores data and/or instructions for performing gesture identification. A gesture identification system may include a wearable gesture identification device. The gesture identification process involves segmenting signals from the sensors into data windows, assigning a respective “window class” to each data window, and identifying a user-performed gesture based on the corresponding sequence of window classes. Each window class exclusively characterizes at least one data window property and is analogous to a “letter” of an alphabet. Under this model, each gesture is analogous to a “word” made up of a particular combination of window classes.