Vehicle Ceiling Microphone Array for Direction-Independent Speech Isolation

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Solution Overview

Problem

Existing techniques for acquiring a signal from a sound mixture in vehicles often fail to effectively isolate speech from noise, especially when the direction of speech or noise changes, leading to suboptimal signal quality.

Innovation Solution

A speech processing apparatus is implemented with two microphones positioned on a vehicle's ceiling and accessory, where the first microphone captures the sound mixture including passenger voice and noise, and the second microphone, placed farther away, isolates noise while insulating the passenger's voice, with a noise suppressor generating an enhanced speech signal based on inputs from both microphones.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a sound insulating member is provided between two microphones to increase the difference between speech inputs, then speech isolation is improved, but speech acquisition becomes impossible from certain directions depending on the direction of speech or noise

Engineering Contradiction:

Improvespeech isolationVSAvoidspeech direction coverage

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The sound insulating member is divided into a first sound insulating portion and a second sound insulating portion that are rotatable relative to each other. This segmentation allows the system to capture speech from multiple directions by rotating the portions to different angular positions, resolving the contradiction between speech isolation and directional coverage.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The sound insulating member is made rotatable around the first microphone, transforming a static structure into a dynamic one. This enables the system to adapt to different speech directions by rotating the insulating portions to appropriate angles, maintaining both isolation performance and directional versatility.

Inventive Principle:

Principle #15Dynamics

2Measurement precision

If microphones are positioned closer to the passenger for better speech capture, then speech signal strength is improved, but noise from the vehicle interior is also increased

Engineering Contradiction:

Improvespeech signal strengthVSAvoidvehicle noise

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The first sound insulating portion acts as an intermediary between the passenger speech and the first microphone, while the second sound insulating portion mediates between the vehicle noise and the second microphone. This intermediary structure allows the microphones to be positioned optimally for speech capture while the insulating portions selectively block noise paths.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Device complexity

If a single microphone is used to simplify the device, then device complexity is reduced, but the ability to separate speech from noise is insufficient

Engineering Contradiction:

Improvemicrophone configurationVSAvoidspeech noise separation

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The audio capture function is segmented into two separate microphones with different positioning and insulation configurations. The first microphone captures speech with noise insulation, while the second microphone captures noise without speech insulation. This segmentation enables effective speech-noise separation while maintaining manageable device complexity.

Inventive Principle:

Principle #1Segmentation

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

This configuration allows for the independent acquisition of high-quality speech signals regardless of speech or noise direction, improving signal quality and productivity.

Implementation Method 1

inputs the noise in the vehicle while insulating the voice of the passenger of the vehicle using one of the ceiling member of the vehicle and the accessory

Methodology Applied

Scientific EffectAcoustic insulation: Absorption (physical)

Data Source

PatentUS9847091B2Speech processing apparatus, speech processing method, speech processing program, method of attaching speech processing apparatus, ceiling member, and vehicle

Publication Date: 2017.12.19 NEC CORP

AI summary

To input the voice of the passenger of a vehicle and output a piece of high-quality enhanced speech independently of the direction of a piece of speech or noise, a speech processing apparatus includes a first microphone that is provided on one of a ceiling member in a vehicle and an accessory thereof, inputs a sound mixture including a voice of a passenger of the vehicle and noise in the vehicle, and outputs a first signal, a second microphone that is provided on one of the ceiling member in the vehicle and the accessory thereof at a position farther than the first microphone when viewed from the passenger of the vehicle, inputs the noise in the vehicle while insulating the voice of the passenger of the vehicle using one of the ceiling member of the vehicle and the accessory thereof, and outputs a second signal, and a noise suppressor that outputs an enhanced speech signal based on the first signal and the second signal.