Audio Noise Suppression Using Drive Instruction Timing

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Solution Overview

Problem

Existing noise suppression methods for audio signals from image-taking apparatuses are hindered by the inclusion of delay periods and improper setting of noise estimation and suppression periods, leading to inadequate noise level estimation and degradation of audio quality.

Innovation Solution

An audio processing device that sets a specific noise period between the drive instruction and the cessation of the drive device's operation, allowing for accurate noise level estimation and suppression, thereby avoiding inclusion of no-noise periods and ensuring proper noise suppression.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the noise level estimation and suppression are performed during the operation period of the drive device, then noise suppression is achieved, but the delay time period is incorrectly included in the operation period, causing the estimated noise level to be excessively low

Engineering Contradiction:

Improvenoise suppression effectivenessVSAvoidnoise level estimation accuracy

Core Design Contradiction:

Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

The patent applies preliminary action by defining the operation period to start from the drive instruction timing rather than the actual drive start timing. This preliminary definition ensures that the delay time period is excluded from noise level estimation, allowing accurate noise measurement while maintaining proper noise suppression effectiveness during actual drive operation.

Inventive Principle:

Principle #10Preliminary action

2Duration of action of moving object

If the delay time period is included in the operation period, then the operation period is extended, but the estimated noise level becomes excessively low, preventing sufficient noise suppression

Engineering Contradiction:

Improveoperation period durationVSAvoidnoise suppression effectiveness

Core Design Contradiction:

Duration of action of moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent segments the operation period into two distinct parts: the delay time period (when drive instruction is issued but drive has not started) and the actual operation period (when drive is running). By segmenting this way, the noise level estimation is performed only during the actual operation period, ensuring accurate noise measurement while maintaining proper noise suppression effectiveness.

Inventive Principle:

Principle #1Segmentation

3Duration of action of moving object

If the period immediately after drive start is included in the operation period, then the operation period is extended, but the estimated noise level is excessively high for this period and excessively low for the following period

Engineering Contradiction:

Improveoperation period durationVSAvoidnoise level estimation accuracy

Core Design Contradiction:

Duration of action of moving objectVSMeasurement precision

Solution Approach 1:

The patent applies preliminary action by setting the operation period to start from the drive instruction timing, which is before the actual drive start. This preliminary timing setup ensures that the unstable period immediately after drive start is properly excluded from noise level estimation, allowing accurate noise measurement during stable operation periods while maintaining proper noise suppression effectiveness.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS8698921B2Audio processing device, audio processing method, program, and audio acquisition apparatus

Publication Date: 2014.04.15 RENESAS ELECTRONICS CORP

AI summary

In an audio-accompanying moving-image taking apparatus, a noise period setting unit sets a second period with respect to an audio signal acquired by image-taking. The second period is a period between the endpoint of a first period which is a predetermined period starting from the timing when a drive instruction is made to a drive unit for driving a lens and the point in time when the drive unit stops driving according to the drive instruction. A noise level estimation unit estimates a noise level using the signal present in the second period set by the noise period setting unit. A noise suppression unit suppresses noise from the signal present in the second period using the noise level estimated by the noise estimation unit.