Microphone Gain Control for Accurate Audio Recognition
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Solution Overview
Problem
Existing information processing apparatuses with audio input functionality using microphones often suffer from usability issues due to ineffective auto gain control (AGC), which can lead to recognition errors during audio recognition tasks.
Innovation Solution
An information processing apparatus with an audio input unit, an amplifier unit capable of auto gain control, and a controller that turns off AGC when an audio recognition application is executed, using detection units to determine if the device is being held by a user and adjusting the gain accordingly, while inhibiting gain switching during audio input.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If auto gain control is enabled in the amplifier unit, then audio levels are automatically adjusted for clear reproduction, but recognition errors occur during audio recognition tasks
Solution Approach 1:
The system dynamically switches the AGC state based on the executed application. When an audio recognition application is detected, the controller turns off AGC to ensure recognition accuracy. For other applications like meeting reproduction, AGC remains on to provide clear audio. This dynamic adaptation resolves the contradiction by making the system behavior context-dependent rather than fixed.
Solution Approach 2:
The controller changes the gain control parameter state (on/off) based on application type. By detecting which application is running and accordingly adjusting the AGC parameter, the system optimizes performance for each specific use case, eliminating recognition errors while maintaining usability for other functions.
2Measurement precision
If gain is adjusted based on device holding state, then audio input quality improves, but gain switching during audio input causes instability
Solution Approach 1:
The system periodically detects the holding state using motion sensors and adjusts gain accordingly, but only during specific periods when audio input is not actively occurring. During active audio input, gain switching is inhibited to maintain stability. This periodic detection with conditional execution resolves the contradiction between adapting to user state and maintaining stability.
Solution Approach 2:
The controller preemptively prevents gain switching during audio input by detecting the audio input state and blocking gain changes. This preliminary protective action ensures that even if the holding state changes, the gain remains stable during critical audio capture periods, preventing instability while still allowing quality optimization during non-critical periods.
3Reliability
If AGC is turned off for audio recognition, then recognition accuracy improves, but audio levels become inconsistent for different usage scenarios
Solution Approach 1:
The system segments audio processing into different modes based on application type. For audio recognition applications, AGC is turned off with fixed gain to ensure accuracy. For other applications like meetings or general reproduction, AGC remains enabled to provide adaptive audio levels. This segmentation allows each mode to be optimized independently, resolving the contradiction between recognition accuracy and general adaptability.
Data Source
AI summary
An information processing apparatus including an audio input unit, an amplifier unit, and a controller. The audio input unit is capable of converting audio into an electric audio signal. The amplifier unit is configured to amplify the audio signal obtained by the audio input unit and capable of performing auto gain control. The controller is configured to turn off the auto gain control of the amplifier unit when an application that uses an audio recognition is executed with respect to the amplified audio signal.