Audio Signal Processing Apparatus for Sound Source Separation
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Solution Overview
Problem
Conventional audio signal processing techniques face challenges in accurately separating a target sound source from non-target sound sources, especially when the target sound source is close to the direction of a non-target sound source, due to limitations in directivity control and beam width narrowing.
Innovation Solution
A signal processing apparatus that divides audio signals into multiple frequency bands and forms directional beams with different directivities for each band, allowing for precise control of directivity and separation of the target sound source by adjusting the beam width and direction based on the target sound source's location.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single directivity beam is formed using a microphone array, then the beam width can be narrowed to some extent, but it is still difficult to accurately separate the target sound source from non-target sound sources when they are close in direction
Solution Approach 1:
The audio signal is divided into multiple frequency bands, and directional beams are formed independently for each frequency band with different directivity characteristics. This segmentation allows each beam to be optimized for specific frequency ranges, improving overall separation accuracy when sound sources are close in direction.
Solution Approach 2:
The invention transitions from forming a single directivity beam to forming multiple directional beams with different directivities across frequency bands. This adds a frequency dimension to the spatial filtering approach, enabling more precise separation of sound sources that are close in directional space.
2Measurement precision
If the beam width is narrowed to improve separation, then directional selectivity increases, but the ability to capture sufficient sound energy from the target source decreases
Solution Approach 1:
The directivity parameters (beam width, direction, shape) are changed across different frequency bands. By adapting the directivity characteristics to each frequency band's properties, the system maintains optimal directional selectivity while capturing sufficient sound energy at each frequency, which collectively provides robust separation performance.
Solution Approach 2:
The directivity characteristics are made dynamic by varying them across frequency bands rather than using a fixed single directivity pattern. This allows the system to adaptively optimize both directional selectivity and energy capture for different frequency components of the sound sources.
Data Source
AI summary
There is provided a signal processing apparatus advantageous in terms of sound source separation performance. The signal processing apparatus includes a dividing unit configured to divide audio signal acquired by a plurality of audio acquisition units into components of a plurality of different frequency bands, and a processing unit configured to form, based on the audio signal, a plurality of directional beams having different directivities in accordance with a target direction and a target width. Each of the plurality of directional beams has directivities in different directions for the respective components of the frequency bands divided by the dividing unit.