Sound Source Positioning With Synchronized Cross-Correlation
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Solution Overview
Problem
Existing spatial audio recording technologies, such as spatial audio microphones, are costly and face challenges in noisy or reverberant environments, making it difficult to accurately identify and isolate individual sound sources for processing, especially when multiple speakers are present or at a distance from the microphone.
Innovation Solution
A method that determines the position of a sound source relative to a reference point using synchronized first and second sound signals, employing generalized cross correlation and phase transform to estimate distance and angle, with optional noise reduction filters and temperature compensation, applicable in various applications including podcasts, film, live events, and virtual reality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If spatial audio microphones are used for capturing sound field information, then position information can be assigned to sound sources, but the cost increases and sound quality deteriorates at large distances or in noisy environments
Solution Approach 1:
The patent introduces a reference microphone as an intermediary element. The reference microphone records a reference sound signal that serves as a benchmark for comparison. By comparing the test sound signal with the reference sound signal through cross-correlation analysis, the system can determine time delays and infer position information without requiring complex spatial audio microphones, thereby maintaining reliability while reducing cost.
Solution Approach 2:
The patent replaces the mechanical/acoustic beamforming system of spatial audio microphones with a signal processing approach using cross-correlation analysis. Instead of relying on the physical arrangement and directional sensitivity of multiple microphone elements, the system uses temporal analysis of sound signals to determine position, substituting a complex mechanical acoustic system with a computational method that achieves similar positioning accuracy with simpler hardware.
2Measurement precision
If spatial audio microphones with beamforming techniques are used, then sound field information can be captured, but the device complexity and cost increase
Solution Approach 1:
The patent extracts only the essential function needed for position determination from the complex spatial audio microphone system. Instead of using the full beamforming capability with multiple directional elements, the invention extracts the core requirement - comparing arrival times of sound at different positions - and implements it through a simple reference microphone and cross-correlation algorithm, eliminating unnecessary complexity while retaining the essential positioning function.
Solution Approach 2:
The patent replaces expensive, complex spatial audio microphones with inexpensive, simple reference microphones. The reference microphone serves as a disposable or simple component that can be easily replaced or repositioned. The value is not in the hardware itself but in the signal processing method that extracts position information, allowing the use of cheap microphones while achieving the same positioning accuracy as expensive specialized equipment.
3Measurement precision
If multiple microphones are used for recording sound signals at different positions, then position determination accuracy improves, but the synchronization complexity increases
Solution Approach 1:
The patent makes the reference sound signal serve multiple functions simultaneously: it acts as a timing reference for synchronization, a benchmark for cross-correlation analysis, and a basis for determining time delays. This multi-functionality eliminates the need for separate synchronization mechanisms, reducing complexity while maintaining precision. The same reference signal that enables position determination also provides the temporal framework for synchronizing multiple recordings.
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 provides precise determination of sound source position, scalable to different quality levels, and is hardware-independent, suitable for real-time and offline processing, improving sound quality and immersion in diverse scenarios.
Implementation Method 1
calculating a time delay between the first sound signal and the at least one second sound signal... calculating a distance between the sound source and the dedicated reference point based on the obtained time delay and a known speed of sound
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.