Sound Processing Apparatus Noise Detection Unit
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Solution Overview
Problem
Existing camera systems face challenges in reducing noise generated inside the housing while capturing sound, as microphone signals often include external and self-noise, leading to potential over-reduction of subject sound and degradation of sound quality.
Innovation Solution
A sound processing apparatus with two microphones - one for environmental sound and another for noise sources - uses a noise detection unit to isolate noise signals and a noise reduction unit to filter out noise from the internal microphone signals, employing a Wiener filter to prevent excessive noise reduction and maintain sound quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If noise reduction processing is performed using sound signals from a microphone inside the housing, then noise generated inside the housing is reduced, but sound from the subject and other non-noise sounds are excessively reduced, degrading sound quality
Solution Approach 1:
The patent divides the sound signal processing into separate components by using multiple microphones positioned at different locations. The first microphone captures environmental sound including subject sound, while the second microphone captures noise from the noise source. This segmentation allows the system to process noise reduction separately from subject sound preservation, preventing the degradation of sound quality while still reducing housing-generated noise.
2Device complexity
If a single microphone inside the housing is used for noise reduction, then the structure is simple, but the system cannot distinguish between noise signals and useful sound signals
Solution Approach 1:
The patent introduces a noise detection unit that acts as an intermediary between the microphones and the noise reduction processing. This unit specifically processes sound signals from the second microphone to generate a noise signal, which then serves as a reference for the noise reduction unit. This intermediary step enables precise noise signal detection and separation from useful sound signals, improving measurement precision without excessive complexity.
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
Effectively reduces lens driving noise while preventing degradation of sound quality by isolating and suppressing self-noise and external noise, ensuring clear and continuous sound capture.
Implementation Method 1
a noise detection unit configured to generate a noise signal of the noise source according to a sound signal from the second microphone
Implementation Method 2
employing a Wiener filter to prevent excessive noise reduction and maintain sound quality
Data Source
AI summary
A sound processing apparatus includes a first microphone which acquires environmental sound, a second microphone which acquires sound of a noise source, and a CPU which causes the sound processing apparatus to function as a noise detection unit configured to generate a noise signal of the noise source according to a sound signal from the second microphone, the noise detection unit reducing sound other than noise of the noise source from the sound signal from the second microphone and generating the noise signal, and a noise reducing unit configured to reduce the noise of the noise included in a sound signal from the first microphone using the sound signal from the noise detection unit.