Imaging Apparatus Noise Reduction via Dynamic Period Detection
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Solution Overview
Problem
Existing imaging apparatuses face challenges in effectively reducing noise from sources other than lens drive noise, such as self-noise and external sound leakage, which can lead to improper noise reduction or excessive subtraction of noise components from the audio signal.
Innovation Solution
The imaging apparatus includes a first microphone for external sounds, a second microphone for drive noise, and a processor that detects noise periods, obtains background noise, generates an audio signal of drive noise, and reduces this noise from the external audio signal using a noise reduction unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If noise from the noise reference microphone is subtracted from the audio signal, then lens drive noise is reduced, but temporary noise other than lens drive noise (self-noise, external sound leakage) is also excessively subtracted
Solution Approach 1:
The patent dynamically adjusts the noise reduction process by detecting whether temporary noise is present in the noise reference microphone. Based on this detection, the system adaptively changes its behavior: when temporary noise is detected, it prevents subtraction to avoid corrupting the audio signal; when only lens drive noise is present, it performs normal subtraction. This dynamic adjustment resolves the contradiction between reducing lens drive noise and maintaining noise reduction accuracy.
Solution Approach 2:
The patent implements a feedback mechanism where the noise period detection unit continuously monitors the noise reference microphone to detect temporary noise. This feedback information is used to control the noise reduction unit's operation. The feedback loop ensures that noise reduction is only performed when appropriate, preventing the excessive subtraction of non-lens noise while still effectively reducing lens drive noise when conditions are favorable.
2Object-affected harmful factors
If noise reduction processing is performed using the noise reference microphone, then lens drive noise is suppressed, but the presence of other noise sources causes improper noise reduction
Solution Approach 1:
The system dynamically adapts its noise reduction strategy based on real-time detection of noise characteristics. When temporary noise is detected in the noise reference microphone, the system switches to a different operational mode that prevents problematic subtraction. This dynamic behavior allows the system to maintain high measurement precision in identifying noise components by recognizing when the noise reference microphone contains only lens drive noise versus when it contains mixed noise sources.
Solution Approach 2:
The patent performs preliminary detection of temporary noise in the noise reference microphone before proceeding with noise reduction processing. This preliminary action allows the system to determine whether the noise reference microphone contains only lens drive noise or also contains temporary noise from other sources. By performing this check in advance, the system can make informed decisions about whether to proceed with standard noise reduction, thereby maintaining accurate noise component identification.
3Object-affected harmful factors
If the noise reference microphone is used for noise reduction, then lens drive noise is reduced, but self-noise and external sound leakage are also subtracted from the audio signal
Solution Approach 1:
The patent extracts and identifies the specific characteristic of temporary noise (self-noise and external sound leakage) in the noise reference microphone through the noise period detection unit. By extracting this information, the system can distinguish between lens drive noise and other unwanted noise sources. This extraction allows the system to selectively handle different noise types, reducing lens drive noise while preventing the subtraction of self-noise and external sound leakage from the main audio signal.
Solution Approach 2:
The noise period detection unit acts as an intermediary between the noise reference microphone and the noise reduction unit. It analyzes the noise reference microphone's signal to detect temporary noise and provides this information to control the noise reduction process. This intermediary function allows the system to mediate between the need to reduce lens drive noise and the need to preserve other audio components, preventing the harmful subtraction of self-noise and external sound leakage.
Data Source
AI summary
An imaging apparatus includes an external-audio microphone that collects an external sound that occurs outside the imaging apparatus, a noise reference microphone that obtains drive noise of the imaging apparatus or an external apparatus connected to the imaging apparatus, a detection unit that detects a noise period during which the drive noise occurs, an updating unit that updates background noise based on an audio signal obtained by the noise reference microphone during a no-noise period determined by the detection unit as a period in which no noise occurs, a generation unit that generates an audio signal of the drive noise from the audio signal obtained by the noise reference microphone and the updated background noise, and a noise reduction unit that reduces the audio signal of the drive noise generated by the generation unit from the audio signal obtained by the external-audio microphone during the noise period.