Microphone Filter Control for Precise Sound Source Positioning

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Solution Overview

Problem

Existing sound pickup devices struggle to accurately detect the position of an object when surrounded by multiple sound sources due to ambient noise interference, even with directional microphones, which fail to selectively pick up sounds from a specific position.

Innovation Solution

A sound pickup device utilizing a processor that calculates acoustic filter factors based on sound frequency and microphone intervals, applying sound amplification and acoustic power minimization controls to create a gradient of sound pressure sensitivity, enhancing directivity and selectively picking up sounds from a specific area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a directional microphone is used to pick up sounds from a specific direction, then sound pickup directionality is improved, but it still cannot selectively pick up sounds from a specific position among multiple sound sources

Engineering Contradiction:

Improvesound pickup directionalityVSAvoidposition estimation accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent divides the sound field into multiple control regions (first control region and second control region) with different sound pressure sensitivity characteristics. By segmenting the acoustic space and applying different filter factors to different regions, the system can selectively enhance sounds from specific positions while suppressing ambient sounds, thereby resolving the limitation of conventional directional microphones that cannot distinguish between sound sources at different positions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies different acoustic filter factors to different spatial regions, creating local quality variations in sound pressure sensitivity. The first control region has higher sound pressure sensitivity than the second control region, allowing the system to selectively pick up sounds from specific local areas. This local differentiation enables accurate position estimation by comparing signal strengths from regions with different sensitivity characteristics.

Inventive Principle:

Principle #3Local quality

2Measurement precision

If ambient sounds are suppressed to improve position estimation accuracy, then measurement precision is improved, but sound amplification control becomes more complex

Engineering Contradiction:

Improveposition estimation accuracyVSAvoidsound amplification control complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent changes the acoustic filter factor parameter based on the sound source position and control region. By dynamically adjusting the filter factor according to the estimated position and region characteristics, the system can suppress ambient sounds while amplifying target sounds. This parameter adaptation simplifies the control logic compared to complex spatial filtering methods, as it only requires adjusting a single filter factor based on position estimates.

Inventive Principle:

Principle #35Parameter changes

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 device achieves accurate estimation of a sound source's position with high directivity, especially in low-frequency ranges, and can operate effectively in reverberant spaces by forming a gradient of sound pressure sensitivity in a narrow area.

Implementation Method 1

acoustic filter factors of acoustic filters applied to microphone acquisition signals

Methodology Applied

Scientific EffectAcoustic filter: Filter (physical)

Implementation Method 2

create a gradient of sound pressure sensitivity, enhancing directivity

Methodology Applied

Scientific EffectSound pressure sensitivity gradient: Pressure Gradient

Implementation Method 3

detect the position of an object by detecting sounds emitted from the object using a microphone

Methodology Applied

Scientific EffectSound detection: Sound

Implementation Method 4

sound amplification control

Methodology Applied

Scientific EffectAcoustic amplification:

Implementation Method 5

acoustic power minimization controls

Methodology Applied

Scientific EffectAcoustic power minimization:

Data Source

PatentUS12526574B2Sound pickup device, storage medium and method

Publication Date: 2026.01.13 KK TOSHIBA

AI summary

A sound pickup device includes a processor with hardware. The processor calculates a first relational expression between acoustic filter factors of acoustic filters applied to microphone acquisition signals acquired by two or more microphones, based on a multiplication factor at a sensitization control point with high sound pressure sensitivity by the two or more microphones and a transfer function between each of the two or more microphones and the sensitization control point. The processor calculates a second relational expression between the acoustic filter factors, based on information of a frequency of a sound source and an interval between the two or more microphones. The processor calculates each of the acoustic filter factors, based on the first relational expression and the second relational expression.