Microphone Array Sound Source Tracking for Noise Suppression

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Solution Overview

Problem

Conventional microphone arrays enhance noise over target sound sources when noise amplitude exceeds the target sound source, resulting in poor sound pickup quality.

Innovation Solution

A sound pickup method and system using a microphone array with a sound source tracking device to determine the distance and direction of a target sound source, calculating appropriate time delays for microphones to enhance the target sound source signal while suppressing noise, by employing a signal processing unit with a delay calculator and processor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional delay-and-sum microphone array processing is used to enhance the loudest sound source, then signal-to-noise ratio is improved for that source, but when noise amplitude exceeds target sound source amplitude, noise is enhanced instead of the target signal resulting in poor sound pickup quality

Engineering Contradiction:

Improvesound pickup qualityVSAvoidnoise enhancement

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system uses a sound source tracking device to continuously monitor and provide feedback about the actual location and identity of target sound sources. This feedback mechanism allows the system to distinguish between target sources and noise sources, ensuring that delay processing enhances only the intended targets rather than the loudest signals which may be noise.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent replaces the conventional mechanical/acoustic approach of simply enhancing the loudest signal with an intelligent tracking system that uses distance and direction information. This substitution allows the system to make informed decisions about which signals to enhance based on spatial information rather than just amplitude, preventing noise enhancement.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Power

If delay processing is applied based on loudest signal detection, then signals from that direction are enhanced, but the target sound source may be suppressed if it is not the loudest source

Engineering Contradiction:

Improvesignal enhancementVSAvoidtarget signal pickup

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The sound source tracking device provides continuous feedback about target source location, enabling the system to adjust delay processing parameters dynamically. This ensures that enhancement is applied to the correct target source even when its amplitude is lower than surrounding noise, maintaining reliable target signal pickup.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system changes the parameters used for signal enhancement from amplitude-based (loudest signal) to spatial-based (tracked target location). By using distance and direction parameters from the tracking device, the system can accurately identify and enhance target signals regardless of their relative amplitude compared to noise.

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If the system enhances signals from the loudest sound source direction, then signal-to-noise ratio improves for that source, but noise from other directions is suppressed including the target source

Engineering Contradiction:

Improvesound source direction determinationVSAvoidsound pickup quality

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The tracking device provides feedback that verifies whether the loudest detected source is actually the target. This feedback loop allows the system to maintain accurate direction determination while preventing enhancement of noise sources, thereby preserving sound pickup quality.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system performs preliminary tracking and identification of the target sound source before applying delay processing. By预先 determining which source is the target through the tracking device, the system can then apply enhancement with confidence that the correct source will be enhanced, not just the loudest one.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS7313243B2Sound pickup method and system with sound source tracking

Publication Date: 2007.12.25 ACER INC

AI summary

A sound pickup system includes a sound source tracking device that is operable to obtain distance and direction values of a target sound source relative to the sound source tracking device, and that determines nearest and farthest ones of a plurality of microphones in a microphone array relative to the target sound source with reference to determined distances of the sound source tracking device from the microphones, and the distance and direction values obtained by the sound source tracking device. A signal processing unit includes a delay calculator for determining appropriate time delays for the microphones with reference to information from the sound source tracking device, and a delay processor for processing signals generated by the microphones in the microphone array by introducing the corresponding time delays determined by the delay calculator into the signals from the microphones.