Sound Processing Device Phase Removal for Ambient Analysis

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Solution Overview

Problem

Conventional sound processing apparatuses using two sound collectors face challenges in accurately analyzing ambient sound due to uneven directivity characteristics caused by acoustic influences, leading to attenuations and phase interferences, which affect the accuracy of sound analysis.

Innovation Solution

A sound processing apparatus that converts collected sound signals into level signals from which phase information is removed, synthesizes these signals from two sound collectors, and analyzes ambient sound based on the synthesized level signal to compensate for attenuations and phase interferences, resulting in uniform directivity characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If sound signals are collected from two sound collectors at different points, then the coverage range of ambient sound analysis is improved, but the accuracy of sound analysis deteriorates due to acoustic influences and phase interferences

Engineering Contradiction:
Improvecoverage range of ambient sound analysisVSAvoidaccuracy of sound analysis
Core Design Contradiction:
Area of stationary objectVSMeasurement precision

Solution Approach 1:

The patent extracts and removes phase information from the sound signals collected by two sound collectors. By converting sound signals to level signals that contain only amplitude information without phase information, the system eliminates phase interferences that would otherwise degrade analysis accuracy, while still maintaining the wide coverage benefit of using two collectors.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces level signals as an intermediary representation between the raw sound signals from two collectors and the final analysis results. These level signals serve as a mediator that preserves amplitude information needed for analysis while discarding phase information that causes interference, thus resolving the contradiction between coverage and accuracy.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If level signals from two sound collectors are synthesized to improve analysis accuracy, then measurement precision is improved, but harmful phase interferences and attenuations are caused due to acoustic influences

Engineering Contradiction:
Improveaccuracy of ambient sound analysisVSAvoidphase interferences and attenuations
Core Design Contradiction:
Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful phase information into a benefit by deliberately removing it. The phase information that would cause interference and attenuation is extracted and discarded, while the amplitude information is preserved and synthesized. This transforms what would be a harmful factor into a beneficial filtering action that improves analysis accuracy.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent extracts phase information from the sound signals before synthesis and removes it from the processing chain. By taking out the phase component that causes harmful interferences and attenuations, the system can safely synthesize level signals from two collectors without suffering from these adverse effects.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If directivity characteristics are made uniform across all directions, then analysis reliability is improved, but acoustic influences from head presence cause attenuations that reduce measurement precision

Engineering Contradiction:
Improvestability of sound direction detectionVSAvoidaccuracy of sound level measurement
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent extracts and removes phase information that is responsible for direction-dependent attenuations caused by head acoustics. By working with level signals that contain only amplitude information, the system achieves uniform directivity characteristics across all directions, improving the reliability of sound direction detection without the measurement errors that would result from head-induced phase interferences.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP2541971B1Sound processing device and sound processing method
Publication Date: 2020.08.12 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP2541971B1 patent drawingFigure 1
  • EP2541971B1 patent drawingFigure 2
  • EP2541971B1 patent drawingFigure 3~4

AI summary

A sound processing apparatus (100), which can improve precision of analyses on ambient sounds, carries out analysis on the ambient sounds based upon collected sound signals acquired by two sound collectors (first sound collector 110-1 and second sound collector 110-2), and the sound processing apparatus (100) is provided with a level signal conversion section (first level signal conversion section 130-1, second level signal conversion section 130-2) that converts the collected sound signal into a level signal, from which phase information is removed,, a level signal synthesizing section (140) that generates a synthesized level signal in which the level signals acquired from the collected sound signals of the two sound collectors (first sound collector 110-1 and second sound collector 110-2) are synthesized, and a detecting and identifying section (160) that carries out analysis on the ambient sounds based upon the synthesized level signal.