Yacht Noise Cancellation Using Segmented Adaptive Filtering
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Solution Overview
Problem
Existing noise cancellation systems for yachts face challenges in efficiently reducing wide band noise due to high computational complexity and the need for complex adaptive filters, which are not satisfactory in the yachting field, and require microphones to be close to speakers to minimize delay, leading to constructive interference.
Innovation Solution
A noise cancellation system using a feedback and feedforward approach with a multi-channel configuration, employing adaptive filters and dynamic coefficient weighting to minimize computational complexity and optimize noise cancellation, allowing for precise noise estimation and broader quiet areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the microphone is placed close to the speaker to minimize delay, then the bandwidth for noise cancellation is improved, but the system complexity and computational requirements increase significantly
Solution Approach 1:
The patent segments the noise cancellation system into multiple independent frequency bands, with each band processed by a separate adaptive filter. This allows parallel processing of different frequency ranges, reducing the computational complexity of each individual filter while maintaining overall system performance across the full bandwidth.
Solution Approach 2:
The patent transitions from a single-channel time-domain processing approach to a multi-channel frequency-domain approach by applying Fast Fourier Transform (FFT). This dimensional change allows the system to process wide band noise effectively without requiring extremely high-order adaptive filters, thus reducing computational complexity.
2Object-affected harmful factors
If high-order adaptive filters are used to cancel wide band noise, then the noise reduction efficiency is improved, but the computational complexity increases substantially
Solution Approach 1:
The patent divides the wide band noise into multiple narrow band frequency segments, each handled by a lower-order adaptive filter. This segmentation reduces the computational burden of each filter while collectively achieving wide band noise cancellation, avoiding the need for a single high-order filter.
Solution Approach 2:
The patent changes the operating parameters of the adaptive filters by using frequency-domain processing through FFT. This transformation allows the system to achieve effective wide band noise cancellation with filters of manageable order, significantly reducing computational complexity compared to time-domain approaches.
3Object-affected harmful factors
If the secondary path is minimized by placing the microphone close to the speaker, then the noise cancellation performance is improved, but the system becomes more difficult to implement and produce
Solution Approach 1:
The patent segments the acoustic field into multiple frequency bands, allowing the secondary path to be characterized and compensated for each band independently. This approach maintains effective noise cancellation performance without requiring the microphone to be placed extremely close to the speaker, simplifying installation and manufacturing.
Solution Approach 2:
The patent introduces an intermediary processing stage using Fast Fourier Transform and frequency-domain adaptive filtering. This intermediary approach allows the system to handle the secondary path effects computationally rather than requiring precise physical positioning, making the system easier to implement and manufacture.
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
Achieves almost optimal noise cancellation with lower computational complexity, precise signal estimates, and minimized secondary path, making it easier to produce and use, while maintaining performance across varying noise conditions.
Implementation Method 1
a microphone (10) configured for receiving first audio signals (SIN) representing noise generated by a primary source of noise (R1)
Implementation Method 2
a secondary source of noise (R2) configured for emitting second audio signals (SOUT) interfering with the noise generated by the primary source (R1)
Data Source
Figure 1a
Figure 1b
Figure 1c
AI summary
The invention discloses a system for cancelling noise in a yacht comprising at least a microphone (10), configured for receiving first audio signals (SiN) generated by a primary source (Rl) of noise, a secondary source (R2) of noise adapted for emitting second audio signals (S0UT) interfering with said first audio signals (SiN), a signal processing unit (20) configured for receiving as input the first audio signals (SIN) and generate as output the second audio signals (SOUT), wherein the processing unit (20) comprises a filtering module (21) with adaptive control, the adapting technique decomposing the band (B) of the input signal in a plurality of sub-bands (Bi) weighted with dynamic coefficients (Di) as a fucntion of their instataneous importance, so as to determining the filtered output signal (SOUT) as a function of the considered sub-band.