Open-Vocabulary Wake Word Embeddings for Edge Keyword Spotting

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Solution Overview

Problem

Existing keyword spotting systems at edge devices are limited by resource constraints, requiring fixed wake words and necessitating transmission of user-recorded audio for model retraining, which affects user experience and resource efficiency.

Innovation Solution

Implement an open-vocabulary keyword spotting system using an MLPMixer-based encoding model and a convolution-based model, allowing for a small footprint user-defined keyword spotting model that processes audio locally without retraining on a server.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If traditional keyword spotting techniques are used with fixed wake words, then the system can be deployed on edge devices with limited resources, but the system cannot recognize custom user-defined wake words

Engineering Contradiction:
Improvewake word customization capabilityVSAvoidmodel retraining complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system creates an embedding representation (a compact numerical copy) of the user's custom wake word that can be stored and compared against incoming audio. Instead of retraining the entire model, the system copies the essential features of the wake word into an embedding vector that fits within edge device memory constraints.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The system performs preliminary processing of the user's wake word recording during an enrollment phase, converting it into an embedding representation before actual keyword spotting begins. This preliminary action prepares the custom wake word data in advance, so that during operation, the system only needs to compare incoming audio against the pre-computed embedding rather than performing full model retraining.

Inventive Principle:
Principle #10Preliminary action

2Adaptability or versatility

If user-recorded audio is transmitted to a server for model retraining, then custom wake words can be recognized, but additional bandwidth, power, and time are consumed

Engineering Contradiction:
Improvecustom wake word recognitionVSAvoidpower consumption
Core Design Contradiction:
Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The edge device performs the wake word embedding computation locally using its own processing capabilities and memory resources. The device serves itself by generating and storing the embedding representation without requiring external server assistance, thereby eliminating the need for audio transmission and reducing power consumption associated with communication and cloud processing.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system extracts only the essential features of the wake word into a compact embedding representation, separating this essential information from the full audio recording. This extraction allows the system to work with a minimal data representation that fits in edge device memory, avoiding the need to transmit or process large amounts of audio data.

Inventive Principle:
Principle #2Taking out (Extraction)

3Measurement precision

If the encoding model stores full audio recordings for wake word detection, then accurate recognition is achieved, but memory requirements exceed edge device capabilities

Engineering Contradiction:
Improvewake word detection accuracyVSAvoidmemory storage requirements
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The system creates an embedding representation (a compact numerical copy) of the user's custom wake word that can be stored and compared against incoming audio. Instead of retraining the entire model, the system copies the essential features of the wake word into an embedding vector that fits within edge device memory constraints.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The system performs preliminary processing of the user's wake word recording during an enrollment phase, converting it into an embedding representation before actual keyword spotting begins. This preliminary action prepares the custom wake word data in advance, so that during operation, the system only needs to compare incoming audio against the pre-computed embedding rather than performing full model retraining.

Inventive Principle:
Principle #10Preliminary action

4Adaptability or versatility

If model retraining is performed on a server, then open-vocabulary capabilities are achieved, but latency increases due to transmission and retraining time

Engineering Contradiction:
Improveopen-vocabulary capabilityVSAvoidwake word enrollment time
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The edge device performs the wake word embedding computation locally using its own processing capabilities and memory resources. The device serves itself by generating and storing the embedding representation without requiring external server assistance, thereby eliminating the need for audio transmission and reducing power consumption associated with communication and cloud processing.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system performs preliminary processing of the user's wake word recording during an enrollment phase, converting it into an embedding representation before actual keyword spotting begins. This preliminary action prepares the custom wake word data in advance, so that during operation, the system only needs to compare incoming audio against the pre-computed embedding rather than performing full model retraining.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS12488789B2Method and device for efficient open vocabulary keyword spotting
Publication Date: 2025.12.02 LG ELECTRONICS INC
  • US12488789B2 patent drawing
  • US12488789B2 patent drawing
  • US12488789B2 patent drawing

AI summary

A computer-implemented method includes receiving enrollment audio from a user comprising a wake word to be enrolled for the device, preprocessing the enrollment audio to obtain a vector representation along at least a feature dimension and a temporal dimension, inputting the extracted vector representation to a trained encoding model to generate an embedding representation of the enrollment audio, wherein the encoding model includes a plurality of mixing blocks, and wherein the feature dimension and the temporal dimension of an output of a first layer of each mixing block are flipped for inputting to a second layer of the mixing block, and storing the generated embedding representation in a memory for use in detecting input of the enrolled wake word.