Automobile Speaker Acoustic Filtering for Call Privacy
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Solution Overview
Problem
Existing hands-free call systems in automobiles do not effectively prevent call contents from being heard by passengers other than the caller, even when the call voice is output from speakers.
Innovation Solution
A call environment generation method and apparatus that adjust sound signals and filter coefficients for speakers in an automobile to ensure that call voice is primarily heard by the driver while masking sounds, such as music, are emphasized for passengers, thereby preventing call contents from being heard by unintended individuals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If call voice is output from speakers in the automobile, then hands-free call functionality is enabled, but call contents can be heard by passengers other than the driver
Solution Approach 1:
The patent applies local quality by generating different acoustic signals for different spatial locations. The call voice is enhanced in the driver's direction while being suppressed in passenger directions, creating location-specific audio characteristics. This is achieved through directional acoustic processing that tailors the sound field to the driver's position, ensuring call privacy while maintaining hands-free functionality.
Solution Approach 2:
The patent segments the acoustic space into different zones (driver zone and passenger zones) and applies different acoustic signals to each zone. By dividing the audio output into direction-specific components, the system can independently control what is heard by the driver versus passengers, thereby preventing call content leakage to unauthorized listeners.
2Measurement precision
If music playback is stopped during call, then call voice clarity is improved, but passenger entertainment is reduced
Solution Approach 1:
The patent segments the audio content into two separate acoustic signals: one for call voice and one for music playback. These segmented signals are then processed independently and directed to different spatial zones, allowing simultaneous delivery of clear call audio to the driver and entertainment music to passengers without mutual interference.
Solution Approach 2:
The patent applies local quality by providing different audio content to different locations. The driver's acoustic environment is optimized for call voice clarity, while passenger areas receive music playback. This location-specific audio delivery allows both functions to coexist without compromising either call clarity or passenger entertainment.
3Object-affected harmful factors
If call voice is directed only to driver, then call privacy is protected, but overall sound distribution becomes complex
Solution Approach 1:
The patent applies universality by using a single acoustic signal processing system to achieve multiple functions simultaneously: call privacy protection, hands-free functionality, and passenger entertainment. The multi-functional acoustic signal generator handles both call voice enhancement and music playback distribution through unified directional processing, reducing the need for separate dedicated systems.
Solution Approach 2:
The patent merges call voice processing and music playback processing into a unified acoustic signal generation system. By combining these functions and processing them through the same directional acoustic framework, the system achieves call privacy protection without requiring entirely separate hardware systems, thereby managing complexity while maintaining multiple functionalities.
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 prevents call contents from being heard by anyone other than the caller, ensuring privacy during hands-free calls in automobiles by strategically managing sound emissions from multiple speakers.
Implementation Method 1
causing the call environment generation apparatus to emit, from a speaker SP n, sound based on a sound signal Sn as an input signal for the speaker SP n and an acoustic signal An as an input signal for the speaker SP n
Data Source
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AI summary
Provided is a technique to generate a call environment that prevents call contents from being heard by a person other than a person speaking on the phone in a case where call voice is output from a speaker. Speakers installed in an automobile are denoted by SP1, ..., SPN, a first filter coefficient used to generate an input signal for a speaker SPn is denoted by Fn(ω), and a second filter coefficient that is different from the first filter coefficient and is used to generate an input signal for the speaker SPn is denoted by ~Fn(ω). A call environment generation method includes: an acoustic signal generation step of generating, when detecting a start signal of a call, a call-time acoustic signal that is obtained by adjusting volume of an acoustic signal to be reproduced during the call, by using a predetermined volume value; a first local signal generation step of generating a sound signal Sn as an input signal for the speaker SPn from a voice signal of the call by using the first filter coefficient Fn(ω); and a second local signal generation step of generating an acoustic signal An as an input signal for the speaker SPn from the call-time acoustic signal by using the second filter coefficient ~Fn(ω).