Audio Processing Apparatus Driving Noise Reduction
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Solution Overview
Problem
Existing image capturing devices face challenges in reducing driving noise from optical system components without increasing cost or size, particularly due to the difficulty in arranging additional noise recording microphones in compact designs and the delay issues associated with frequency domain noise removal processing.
Innovation Solution
A two-channel microphone configuration is used, where one microphone targets external sound and the other targets driving noise, with an adaptive filter system that processes time-series audio data to reduce driving noise without the need for a dedicated noise detection microphone, utilizing correlation processing and phase difference detection to generate noise-reduced audio data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a noise recording microphone is added to detect driving noise, then driving noise reduction is improved, but device cost and area increase
Solution Approach 1:
The patent makes the existing two-channel microphone unit perform dual functions: capturing external sound and detecting driving noise. By strategically positioning the two microphones and using adaptive noise cancellation processing, the system eliminates the need for a dedicated third microphone, thus reducing device area while maintaining noise reduction capability
Solution Approach 2:
The system uses the existing two-channel microphone configuration to serve itself for noise detection. The microphones are positioned to capture both external sound and driving noise, and the noise cancellation processing utilizes the difference between the two channels to identify and remove driving noise without requiring additional dedicated noise detection hardware
2Object-affected harmful factors
If frequency domain noise removal processing is used, then driving noise reduction is improved, but recording sound delay increases
Solution Approach 1:
The patent replaces frequency domain processing (FFT-based methods) with time domain adaptive filtering. The adaptive filter processes audio signals in the time domain using correlation-based noise cancellation, which eliminates the computational overhead and delay associated with frequency domain transformation and inverse transformation, thus reducing recording delay while maintaining effective noise reduction
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
This approach effectively reduces driving noise without adding a dedicated noise microphone, avoiding processing delays and maintaining compact device design, allowing for real-time noise removal during audio recording.
Implementation Method 1
a correlation processing unit configured to obtain a correlation value between phases of time-series audio data acquired by the first microphone and time-series audio data acquired by the second microphone
Implementation Method 2
a determination unit configured to determine whether or not the driving noise occurred based on the difference between time-series audio data acquired by the first microphone and time-series audio data acquired by the second microphone
Data Source
AI summary
The present invention makes it possible to reduce noise from a driving unit with a two-channel microphone configuration. An audio processing apparatus has a first microphone whose main acquisition target is sound from outside of the apparatus, a second microphone whose main acquisition target is driving noise from the driving unit, and a noise removing unit that generates two-channel audio data in which driving noise made by the driving unit of the apparatus has been reduced based on the difference between time-series audio data acquired by the first microphone and time-series audio data acquired by the second microphone. This noise removing unit has two adaptive filter units that respectively perform filter processing on time-series audio data from the first microphone and time-series audio data from the second microphone, and generates stereo two-channel audio data.