Adaptive Speech Intelligibility Control for Directional Privacy Audio
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Solution Overview
Problem
In voice communication environments, there is a need to maintain speech privacy beyond a specified listening area to prevent unintentional listeners from understanding conversations, as existing technologies fail to effectively control speech intelligibility and noise levels.
Innovation Solution
An adaptive speech intelligibility control system that uses directional speakers, noise estimation, and gain value adjustment based on background noise and listener distance, employing modules for noise estimation, comparison, gain determination, and application, along with camera-based tracking for precise listener positioning, to ensure on-axis intelligibility while reducing off-axis comprehension.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If speech is transmitted at high level to ensure intelligibility within listening area, then speech privacy is compromised and unintentional listeners can understand conversations
Solution Approach 1:
The system applies different gain values to different spatial locations by using directional speakers to create location-dependent speech intelligibility. Listeners within the specified area experience high intelligibility while those outside experience reduced intelligibility, achieving spatially varying quality rather than uniform transmission
Solution Approach 2:
The system dynamically adjusts the gain value applied to speech signals based on real-time conditions including background noise levels, listener distance, and desired intelligibility targets. This dynamic adaptation allows the system to maintain speech privacy while ensuring adequate intelligibility within the listening area
2Object-affected harmful factors
If speech is transmitted at low level to maintain speech privacy, then speech intelligibility within listening area deteriorates
Solution Approach 1:
The system changes key parameters including gain value, noise estimate, and speech level estimate to optimize the balance between speech privacy and intelligibility. By adjusting these parameters based on environmental conditions and listener characteristics, the system achieves both privacy protection and adequate comprehension within the listening area
3Object-affected harmful factors
If background noise is increased to mask speech for privacy, then speech intelligibility for intended listeners is reduced
Solution Approach 1:
The system creates location-dependent masking effects where background noise selectively masks speech for off-axis listeners while preserving intelligibility for on-axis listeners. This spatially differentiated masking achieves privacy through noise without compromising communication quality for intended recipients
4Object-affected harmful factors
If directional speakers and adaptive control systems are implemented, then speech privacy is improved, but device complexity increases
Solution Approach 1:
The system uses feedback loops to continuously monitor speech levels, background noise, and listener characteristics, then automatically adjusts gain values and other parameters. This closed-loop control simplifies operation by eliminating manual configuration while achieving sophisticated speech privacy through adaptive algorithms
Data Source
AI summary
In some examples, adaptive speech intelligibility control for speech privacy may include determining, based on background noise at a near-end of a speaker, a noise estimate associated with speech emitted from the speaker, and comparing, by using a specified factor, the noise estimate to a speech level estimate for the speech emitted from the speaker. Adaptive speech intelligibility control for speech privacy may further include determining, based on the comparison, a gain value to be applied to the speaker to produce the speech at a specified level to maintain on-axis intelligibility with respect to the speaker, and applying the gain value to the speaker.