Baffle Section Asymmetry for Sound Source Detection Accuracy
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Solution Overview
Problem
Conventional sound source detection apparatuses fail to distinguish between sound sources symmetric with respect to the microphone array plane, as they cannot differentiate between phase differences from sound sources on the front and back surfaces, leading to interference from non-target sound sources and reduced detection accuracy.
Innovation Solution
A sound source detection apparatus with a baffle section that arrays microphone elements closer to the center than the outer edge, forming a predetermined angle with the installation surface, effectively increasing phase differences from the back surface and reducing interference, allowing for more accurate detection of sound sources on the target side.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a microphone array is used for sound source detection, then the structure is simple and installability is high, but the apparatus cannot distinguish between sound sources symmetric with respect to the array plane
Solution Approach 1:
The patent introduces a baffle section that creates asymmetric acoustic paths for sound waves arriving from the front and back surfaces. The baffle has different structures on its first surface (facing the detection target) and second surface (opposite side), causing sound waves from the back surface to undergo diffraction and produce different phase differences compared to front surface sources. This asymmetry enables the system to distinguish between symmetric sound sources while maintaining the simplicity of the microphone array structure.
Solution Approach 2:
The baffle section acts as an intermediary element between the sound sources and the microphone array. It modifies the acoustic environment by diffracting sound waves from the back surface, thereby creating distinguishable phase difference patterns. The baffle mediates the interaction between sound waves and microphones, enabling the simple array structure to achieve improved sound source discrimination capability.
2Adaptability or versatility
If sound waves from the back surface are not suppressed, then the detection coverage is maintained, but noise from the back surface interferes with sound source detection on the target side
Solution Approach 1:
The baffle section is designed with different local qualities on its first and second surfaces. The first surface (facing the detection target) has characteristics that allow sound waves from the target side to pass through with minimal distortion, while the second surface (opposite side) has structures that cause diffraction and modify phase differences for back surface sounds. This local differentiation allows the system to maintain detection coverage for front surface sources while suppressing noise from the back surface.
3Device complexity
If phase differences from symmetric sound sources are equal, then the calculation is simple, but the detection accuracy is reduced due to inability to distinguish front and back sound sources
Solution Approach 1:
The baffle section introduces asymmetry in the acoustic path lengths and phase relationships for sound waves arriving from the front and back surfaces. Even though the microphone array geometry remains simple, the baffle creates different effective phase differences for symmetric sound sources, allowing the existing simple calculation methods to achieve improved detection accuracy without increasing computational 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
The apparatus can reliably detect sound sources on the target side by enhancing phase differences and reducing noise from the back surface, improving detection accuracy and sensitivity.
Implementation Method 1
the baffle section allows a plurality of microphone elements to pick up direct sound from a sound source located at the side of the first surface and prevents the plurality of microphone elements from picking up direct sound from a sound source located at the side of the second surface by effecting diffraction of sound waves generated by the sound source located at the side of the second surface
Data Source
Figure 1
Figure 2(a)~2(b)
Figure 3
AI summary
A sound source detection apparatus is provided which can more surely detect a sound source located in a detection target region. The sound source detection apparatus includes a plurality of microphone and a buffle. The buffle has a first surface and a second surface. The second surface is a surface opposite to the first surface. The plurality of microphones are two-dimensionally arrayed and fixed in the first surface. The buffle allows the plurality of microphones to pick up direct sound arriving at the first surface and prevents the plurality of microphones from picking up direct sound arriving at the second surface.