Zone-Based Language Signal Masking Through Spectral Band Exchange
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Solution Overview
Problem
Existing communication systems in public settings, such as vehicles or public transportation, often lead to unwanted overhearing of private conversations, which can be mitigated by loud noise but at the cost of increased noise levels and discomfort.
Innovation Solution
A zone-based audio system generates a masking signal by transforming speech signals into spectral bands, commuting these bands to alter the spectral structure, and producing a noise signal that mimics the speech signal but with reduced energy, which is then output in adjacent zones to reduce intelligibility without significantly increasing overall sound levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If loud noise is played to reduce unwanted overhearing, then speech intelligibility of the speaker is improved, but the noise level for all parties involved increases and causes unpleasant impairment
Solution Approach 1:
The masking signal is selectively output only in adjacent audio zones where overhearing occurs, rather than uniformly across all zones. The system determines which zones require masking based on spatial information about the speaker and listener positions, applying the masking effect locally only where needed to prevent unwanted overhearing while maintaining comfort in other areas.
Solution Approach 2:
The system generates a masking signal with specific spectral characteristics that match the speech signal's frequency content. By analyzing the speech signal's spectrum and creating a masking signal with similar spectral distribution, the system effectively masks speech intelligibility without using high-amplitude noise that would cause discomfort. The masking signal's parameters are adapted to the detected speech characteristics.
2Loss of information
If a masking signal is generated to reduce speech intelligibility, then privacy protection is improved, but the complexity of the audio system increases
Solution Approach 1:
The audio system is divided into multiple independent audio zones, each with its own masking capability. Rather than requiring a single complex system-wide masking mechanism, each zone can independently detect speech and generate appropriate masking signals. This modular approach reduces overall system complexity while enabling effective privacy protection.
Solution Approach 2:
The system uses the detected speech signal itself as the basis for generating the masking signal. By analyzing the spectral characteristics of the actual speech and creating a masking signal derived from that same signal, the system achieves effective masking without requiring external reference signals or complex pre-programmed masking patterns. The speech signal serves dual purposes: communication and masking generation.
3Loss of information
If spectral bands are commuted to create masking signal, then masking effectiveness is improved, but the energy content of the masking signal increases
Solution Approach 1:
The system commutes only the necessary spectral bands to achieve effective masking, rather than randomly shuffling all frequency components. By selectively exchanging spectral energy between specific bands, the system creates sufficient masking effect while minimizing the total energy required. The partial action approach optimizes the balance between masking effectiveness and energy consumption.
Data Source
AI summary
The present disclosure relates to a method for masking a language signal in a zone-based audio system, involving: acquiring, in an audio zone, a language signal to be masked; transforming the acquired language signal into spectral bands; interchanging spectral values of at least two spectral bands; generating a noise signal on the basis of the interchanged spectral values; and outputting the noise signal as a masking signal for the language signal in another audio zone.