Blind Source Separation for Vehicle Noise Contribution Analysis
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Solution Overview
Problem
Current acoustic measurement systems for determining individual noise sound contributions from multiple physical noise sources in motorized vehicles are prone to errors due to simplifying assumptions, such as treating noise sources as point sources, and are time-consuming and impractical, especially when dealing with complex vehicle constructions.
Innovation Solution
A method using blind source separation to record noise sound signals from reference microphones placed near noise sources and a measurement microphone at a target location, correlating these signals to determine linear transfer path filters and isolate individual noise sound contributions, allowing for accurate assessment of noise contributions without the need for complex data acquisition processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If reciprocal or reverse acoustic transfer path based methodologies are used to determine noise sources, then individual noise sound contributions can be identified, but measurement precision deteriorates due to simplifying assumptions such as modeling noise sources as point sources
Solution Approach 1:
The patent replaces traditional mechanical/acoustic measurement systems with a signal processing-based approach. Instead of using complex physical measurement setups with multiple microphones and transfer path analysis, the invention uses blind source separation algorithms to computationally separate noise sources from mixed signals, thereby improving accuracy while reducing physical measurement complexity
Solution Approach 2:
The patent creates virtual copies of noise sources through signal processing. By recording mixed noise signals and applying blind source separation, the system generates independent signal representations of each noise source without physically separating them, allowing accurate analysis of distributed noise sources without complex physical measurement arrangements
2Measurement precision
If data acquisition is performed during operational conditions with multiple noise sources, then individual contributions can be determined, but the process becomes time-consuming and impractical for complex vehicle constructions
Solution Approach 1:
The patent enables continuous measurement during vehicle operation. By using blind source separation on signals recorded during normal operational conditions, the system can continuously identify and separate noise contributions without interrupting vehicle operation or requiring separate measurement phases, thereby eliminating time losses associated with traditional measurement procedures
Solution Approach 2:
The system uses the vehicle's own operational noise signals as the measurement data. Instead of requiring external test equipment or separate measurement campaigns, the blind source separation algorithm processes signals already present during normal vehicle operation, making the measurement process self-contained and eliminating additional time requirements
Data Source
AI summary
The present invention relates to a method and an acoustic measurement system for determining individual noise sound contributions of a plurality of physical noise sources of a motorized vehicle at a target or reference location. The method comprises steps of placing a plurality of reference microphones at respective reference positions adjacent to respective ones of the physical noise sources, placing a measurement microphone at the target location, recording a plurality of noise sound signals and recording a target noise signal. The plurality of noise sound signals are adaptively separated using blind source separation to produce a plurality of mutually independent noise sound signals representing respective estimated noise sound signals of the plurality of physical noise sources. Each of the mutually independent noise sound signals is correlated with the recorded target noise signal to determine time domain or frequency domain characteristics of a plurality of linear transfer path filters representing respective transfer functions between the plurality of independent noise sound signals and the measurement microphone at the target location. At least one of the independent noise sound signals, representing one of the physical noise sources, may be applied to the corresponding linear transfer path filter to generate at least one target noise signal component representing the individual noise sound contribution of the physical noise source at the target location.