Audio Processing Device Frequency Spectrum Occupancy Rate Suppression

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Solution Overview

Problem

Changes in the surrounding environment can reverse the magnitude of desired and undesired sounds, leading to decreased separation accuracy and errors in audio analysis, particularly in binary masking techniques used for audio recognition and analysis.

Innovation Solution

An audio processing method that analyzes frequency spectra from multiple input devices, estimates noise spectra, and calculates a suppression amount based on occupancy rates to improve sound separation accuracy, using a suppression amount calculation function that adjusts suppression levels according to the occupancy rate of each frequency spectrum.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If binary masking is used for audio analysis by comparing signal levels, then the desired sound can be separated from undesired sound, but separation accuracy decreases when magnitude of desired and undesired sounds is reversed due to environment changes

Engineering Contradiction:
Improveseparation accuracyVSAvoidaudio analysis accuracy
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent applies dynamics by making the audio analysis adaptive to environmental changes. The system dynamically adjusts the analysis process by detecting occupancy rates of frequency spectra and modifying the separation approach based on whether the environment is occupied or unoccupied, allowing it to handle both normal and reversed magnitude scenarios effectively

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes parameters by introducing occupancy rate detection and using different analysis strategies based on the detected state. When the occupancy rate indicates an unoccupied state, the system switches to alternative frequency spectrum analysis methods, effectively adapting to environmental changes and maintaining accuracy regardless of sound magnitude reversals

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If suppression processing is applied to frequency spectra, then undesired sounds can be suppressed, but the complexity of the audio processing increases

Engineering Contradiction:
Improvesound separation accuracyVSAvoidaudio processing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the audio processing into distinct stages: frequency spectrum analysis, occupancy rate detection, state determination, and suppression processing. This segmented approach allows each component to be optimized independently while maintaining overall system efficiency and accuracy

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent uses preliminary action by performing frequency spectrum analysis and occupancy rate detection before applying suppression processing. This preliminary analysis allows the system to determine the appropriate suppression strategy in advance, avoiding unnecessary complex processing when simple methods suffice

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3291228B1Audio processing method, audio processing device, and audio processing program
Publication Date: 2020.04.01 FUJITSU LTD
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AI summary

An audio processing method including: generating a plurality of frequency spectra by transforming a plurality of audio signals inputted to a plurality of input devices respectively, determining target frequencies where an amplitude difference between a frequency spectrum and a noise spectrum is larger than a threshold, determining occupied frequencies in a frame with respect to each target frequencies to specify a frequency spectrum having the largest signal level among the plurality of input frequency spectra. Based on the total number of target frequencies and a total number of occupied frequencies, determining an occupancy rate as a proportion of the total number of the occupied frequencies to the total number of the target frequencies. Determining a suppression amount by substituting the occupancy rate in a suppression amount calculation function. Applying the suppresion amount by multiplying a frequency spectrum.