Throat Microphone Interference Cancellation via Physiological Filtering

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Solution Overview

Problem

In noisy environments, throat microphones face challenges in distinguishing human speech from background noise and other vibrations, as they do not directly sense audible noise signals, leading to interference from secondary physiological phenomena like breathing and heartbeat.

Innovation Solution

A method and system that utilize a processor to receive vibration signals from a throat microphone, identify characteristics associated with secondary physiological phenomena, determine filter control parameters, and apply filtering to isolate the desired sonic signal, such as speech, by using a filter bank and high-pass filters to remove unwanted frequencies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a throat microphone is used to sense vibrations, then audible noise signals are excluded, but secondary physiological phenomena (breathing, heartbeat) create interference

Engineering Contradiction:
Improveaudible noise signalsVSAvoidsecondary physiological phenomena
Core Design Contradiction:
Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The patent extracts and removes the harmful secondary physiological phenomena (breathing, heartbeat) from the vibration signal using digital filtering techniques. The system identifies frequency components associated with these phenomena and selectively removes them while preserving the desired speech signal.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the frequency domain parameters of the vibration signal by applying Fast Fourier Transform (FFT) to convert the time-domain signal to frequency-domain representation. This allows selective manipulation of frequency components to eliminate physiological interference.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If filtering is applied to remove secondary physiological phenomena, then speech clarity is improved, but signal processing complexity increases

Engineering Contradiction:
Improvespeech clarityVSAvoidsignal processing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent implements an adaptive filtering approach where the system continuously analyzes the vibration signal to identify characteristics of secondary physiological phenomena and dynamically adjusts filter parameters accordingly. This feedback mechanism optimizes speech clarity while managing processing complexity through intelligent adaptation.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent performs preliminary analysis of the vibration signal to identify frequency characteristics of physiological phenomena before applying the filtering operation. This pre-processing step allows the system to configure optimal filter parameters in advance, reducing the computational burden during the actual filtering process.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS9930445B2Interference cancellation for throat microphone
Publication Date: 2018.03.27 INVENSENSE INC
  • US9930445B2 patent drawing
  • US9930445B2 patent drawing
  • US9930445B2 patent drawing

AI summary

A throat microphone may include one or more transducers that are in contact with the skin in the region of the larynx of person, and may provide a vibration signal to a processing unit. The vibration signal may also include energy and information relating to secondary physiological phenomena such as breathing and heartbeat, in addition to the desired sonic signal. The processing unit may utilize information relating to the secondary physiological phenomena to control a filter that outputs the desired sonic signal.