Sound Source Positioning via Signal Correlation
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Solution Overview
Problem
Existing spatial audio recording techniques, such as those using spatial audio microphones, face challenges including reduced sound quality at distances, difficulty in identifying and isolating individual sound sources in noisy or reverberant environments, and high costs.
Innovation Solution
A method for determining the precise position of a sound source relative to a dedicated reference point, independent of hardware, using synchronized first and second sound signals. This method involves filtering and correlating the signals to estimate distance and angle, and can be applied in various scenarios including podcasts, film, and virtual reality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If spatial audio microphones are used for recording, then sound field information can be captured, but sound quality deteriorates at large distances and costs increase
Solution Approach 1:
The patent divides the recording system into multiple separate microphones positioned at known locations rather than using a single spatial audio microphone. This segmentation allows for better sound quality at various distances by selecting or combining signals from microphones optimally positioned relative to the sound source.
Solution Approach 2:
The patent creates a universal positioning method that works with standard microphones regardless of distance, environment, or sound source type. The method can handle various scenarios (noisy environments, reverberant spaces, multiple speakers) using the same basic approach of recording at multiple known positions and processing the signals accordingly.
2Loss of information
If spatial audio microphones are used, then sound field information is captured, but difficulty increases in identifying and isolating individual sound sources in noisy or reverberant situations
Solution Approach 1:
The patent introduces signal processing operations as intermediaries between the raw microphone recordings and the final sound source identification. Specifically, cross-correlation and filtering operations are applied to the recorded signals to enhance the ability to identify and isolate individual sound sources even in noisy or reverberant environments.
Solution Approach 2:
The patent replaces the mechanical/physical approach of using specialized spatial audio microphones with a signal processing approach. Instead of relying on the physical characteristics of a single complex microphone, the system uses multiple simple microphones and processes their signals computationally to achieve sound source identification and isolation.
3Measurement precision
If spatial audio microphones are used, then sound field information is captured, but costs increase
Solution Approach 1:
The patent replaces expensive spatial audio microphones with multiple inexpensive standard microphones. The system achieves the same or better results by using cheap, readily available recording devices positioned at known locations, eliminating the need for costly specialized equipment.
Solution Approach 2:
The patent creates multiple copies of the recording function using separate microphones at different positions rather than relying on a single expensive spatial audio microphone. This allows the system to capture spatial information through redundancy and subsequent signal processing rather than through expensive specialized hardware.
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 method allows for accurate determination of sound source position, is scalable, and can be used in both offline and real-time processing, enhancing the flexibility and quality of spatial audio applications.
Implementation Method 1
the first sound signal is correlated with at least one of the plurality of second sound signals in the frequency domain to obtain at least one correlated signal
Implementation Method 2
A filter is now estimated for the first sound signal acting on the signal-to-noise ratio in each frequency bin of the first sound signal in a time-frequency domain
Implementation Method 3
the recorded sound signals can be used to provide the time base, e.g. by timely correlating a dedicated start signal that is recorded and included in the first and the plurality of second sound signals
Data Source
AI summary
The invention relates to a method for obtaining a position of a sound source relative to a dedicated reference point. A first and a plurality of second sound signals are recorded which are synchronized in time. The position can be obtained by applying an estimated filter to a correlated signal derived by correlation of the first sound signal with at least one of the plurality of second sound signals in the frequency domain. Two timing values are derived in the at least one filtered and correlated signal exceeding a dedicated threshold in the time domain. Then the distance between the dedicated reference point and the sound source based on the respective obtained first timing value and second timing value.