Audio Encoding via Microphone Array Spatial Analysis
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Solution Overview
Problem
Portable wireless devices face challenges in distinguishing between foreground and background audio signals, leading to compromised audio encoding efficiency due to difficulty in determining the angular location and distance of sound sources in acoustical environments.
Innovation Solution
A system utilizing a microphone array and processor to determine the angular location and distance of sound sources based on reverberation characteristics, classifying audio signals as foreground or background to optimize bit allocation for encoding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If audio signals are encoded at similar bit-rates, then encoding simplicity is maintained, but audio encoding efficiency is compromised
Solution Approach 1:
The patent applies local quality by differentiating audio signals based on their spatial characteristics. Foreground audio signals (closer sound sources) are encoded at higher bit-rates while background audio signals (farther sound sources) are encoded at lower bit-rates. This localized differentiation of encoding quality based on distance from the microphone array optimizes encoding efficiency without requiring uniform high-quality encoding for all signals.
Solution Approach 2:
The patent implements preliminary action by determining the angular location and distance of sound sources before encoding the audio signals. The processor analyzes the audio signals to identify reverberation characteristics and calculate the distance of sound sources from the microphone array. This preliminary spatial analysis enables subsequent bit-rate allocation to be optimized based on the pre-determined spatial information, separating foreground and background signals for differential encoding.
2Measurement precision
If the wireless telephone determines angular location and distance of sound sources, then audio signal classification accuracy is improved, but processing complexity increases
Solution Approach 1:
The patent uses reverberation characteristics as an intermediary parameter to indirectly determine the distance of sound sources. Instead of directly measuring distance through complex geometric calculations, the system analyzes the reverberation properties of the audio signal (such as reverberation time, early reflections) which correlate with the distance of the sound source. This intermediary approach simplifies the processing while maintaining accurate spatial information for foreground/background classification.
Data Source
AI summary
An apparatus for detecting a sound in an acoustical environment includes a microphone array configured to detect an audio signal in the acoustical environment. The apparatus also includes a processor configured to determine an angular location of a sound source of the audio signal. The angular location is relative to the microphone array. The processor is also configured to determine at least one reverberation characteristic of the audio signal. The processor is further configured to determine a distance, relative to the microphone array, of the sound source along an axis associated with the angular location based on the at least one reverberation characteristic.