Separating Component for Speech Masking via Dynamic Signal Superimposition

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Solution Overview

Problem

Existing solutions for reducing speech signal intelligibility in open-plan offices and preventing eavesdropping are inadequate, as they either result in high noise levels or fail to effectively minimize speech intelligibility through typical building structures, which are not user-friendly and require expensive construction technologies.

Innovation Solution

A method and separating component that detect the amplitude, time, and frequency of speech signals to generate a masking sound in real-time, which is superimposed with the speech signal to create an incomprehensible sound without significantly increasing volume, using sensors and actuators integrated into multi-layer separating components like walls and ceilings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If speech signals are overlaid with noise signals to reduce intelligibility, then eavesdropping is prevented, but noise level becomes comparatively high

Engineering Contradiction:
Improveprotection against eavesdroppingVSAvoidnoise level
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies parameter changes by dynamically adjusting the masking signal parameters (amplitude, frequency, time characteristics) based on the detected speech signal parameters. The masking signal is generated with amplitude and frequency that adapt to the speech signal's characteristics, ensuring effective eavesdropping prevention while minimizing unnecessary noise. The system changes the masking signal parameters in real-time to match speech intensity and frequency content, rather than using constant high-level noise.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system implements dynamics by continuously detecting speech signal parameters and dynamically generating masking signals with varying amplitude, frequency, and temporal characteristics. The masking signal is not static but adapts moment-by-moment to the speech content, creating an incomprehensible superimposed sound only when speech is detected and with parameters matched to the speech signal, thereby reducing overall noise levels.

Inventive Principle:
Principle #15Dynamics

2Object-affected harmful factors

If sound insulation and soundproofing are increased in open-plan offices, then speech distraction is reduced, but construction complexity and cost increase

Engineering Contradiction:
Improvespeech distractionVSAvoidconstruction complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent replaces mechanical sound insulation measures (thick walls, complex construction) with an acoustic field-based solution using sensors and actuators that generate masking signals. Instead of physically blocking sound transmission through heavy construction, the system uses electronic detection and acoustic countermeasures to prevent speech intelligibility, thereby reducing construction complexity while maintaining effectiveness.

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

Solution Approach 2:

The system changes the approach from static structural modifications to dynamic parameter-based control. By detecting speech signal parameters and generating masking signals with corresponding characteristics, the system achieves speech distraction reduction without requiring increased construction complexity or expensive soundproofing materials.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If masking signals are generated with high amplitude to ensure incomprehensibility, then eavesdropping prevention is effective, but acoustic disturbance in the room increases

Engineering Contradiction:
Improveeavesdropping prevention effectivenessVSAvoidacoustic disturbance
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies parameter changes by generating masking signals with amplitude, frequency, and temporal characteristics that are specifically adapted to match the detected speech signal parameters. The masking signal amplitude is set based on the speech signal intensity and frequency content, ensuring effective eavesdropping prevention while minimizing acoustic disturbance. The system dynamically adjusts parameters rather than using fixed high-amplitude signals.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system applies local quality by creating masking effects specifically targeted at the speech frequency ranges and spatial locations where speech signals are detected. The masking signal parameters are localized to match the speech characteristics, providing effective eavesdropping prevention in the relevant frequency bands while minimizing disturbance in other frequency ranges and spatial zones.

Inventive Principle:
Principle #3Local quality

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

The solution effectively reduces speech intelligibility while maintaining a low acoustic disturbance, making eavesdropping more difficult without the need for high noise levels, and can be integrated into existing building structures, enhancing security against eavesdropping.

Implementation Method 1

sensors for detecting the speech signal coming from the room

Methodology Applied
Scientific EffectAcoustic detection:

Implementation Method 2

actuators for generating a masking sound

Methodology Applied
Scientific EffectAcoustic generation:

Implementation Method 3

superimposition of the speech signal with the masking sound results in an incomprehensible superimposed sound

Methodology Applied
Scientific EffectSound superimposition: Interference

Data Source

PatentEP3178184B1Separating component for influencing sound transmission
Publication Date: 2021.04.28 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV
  • EP3178184B1 patent drawingFigure 1

AI summary

The invention relates to a method for reducing the comprehensibility of a speech signal, involving the following steps: a) detecting the amplitude, variation over time, and frequency of the speech signal (8); b) generating a masking sound (9) which is dependent on the amplitude, variation over time, and frequency of the speech signal (8) in such a way that an incomprehensible superimposed sound (12) is created by superimposing the masking sound (9) on the speech signal (8), said superimposed sound (12) not being significantly louder than the speech signal, the masking sound (9) being generated in a randomly changing manner, and the speech signal (8) being split into intervals, characterized in that the length of the intervals is randomly modified according to a randomization function. The invention also relates to a separating component for separating a room (2) from a room environment (3) using sensors (4), actuators (5) and a signal processing unit (6) in order to influence sound transmission, characterized in that the separating component (1) includes the following parts: sensors (4) for detecting the speech signals (8) from the room (2); actuators (5) for generating a masking sound that is dependent on the amplitude, variation over time, and frequency of the speech signal (8); the sensors (4) and the actuators (5) being located at a distance from one another so that the speech signal (8) has a certain propagation time until the masking sound (9) is superimposed thereupon in order to take into account propagation times of the speech signal (8) in the separating component (1).