Adaptive Filter Coefficient Adjustment for Vehicle Window Noise
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Solution Overview
Problem
Existing vehicle sound improvement technologies, such as Engine Order Cancellation (EOC) and Engine Sound Synthesis (ESS), face challenges in maintaining effective noise reduction and sound quality when the vehicle's sound environment changes, particularly when the window is open, leading to potential divergence of adaptive filters and abnormal signal output.
Innovation Solution
An apparatus that adjusts the adaptive filter coefficient based on the window open degree and vehicle speed, using an auxiliary path transfer function to match the current sound environment and prevent abnormal signal output by turning off the EOC function when noise exceeds a threshold, thereby minimizing performance degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the window is open during driving, then ventilation and user comfort are improved, but wind noise is introduced into the vehicle interior causing engine noise cancellation to fail
Solution Approach 1:
The system dynamically switches between different auxiliary path transfer functions based on window opening state and vehicle speed. When the window is open, the system selects a transfer function suitable for the changed acoustic environment, allowing the EOC function to maintain effectiveness despite the open window condition.
Solution Approach 2:
The system changes the auxiliary path transfer function parameters based on window opening degree and vehicle speed. By adjusting these parameters according to the operating conditions, the system adapts to different sound environments and maintains noise cancellation performance.
2Reliability
If the adaptive filter coefficient is adjusted in real-time based on window open degree and vehicle speed, then the EOC function performance is maintained, but the system complexity increases
Solution Approach 1:
The system pre-defines multiple auxiliary path transfer functions corresponding to different window opening degrees and vehicle speed ranges. Instead of performing complex real-time calculations, the system selects from pre-prepared transfer functions based on current conditions, reducing computational complexity while maintaining performance.
Solution Approach 2:
The system uses feedback from window open degree sensors and vehicle speed sensors to automatically select the appropriate auxiliary path transfer function. This feedback mechanism allows the system to adapt to changing conditions without requiring complex manual intervention or calculation.
3Reliability
If the EOC function is turned off when noise exceeds threshold, then abnormal signal output is prevented, but noise reduction capability is lost during high wind conditions
Solution Approach 1:
The system changes the auxiliary path transfer function parameters based on noise levels and operating conditions. When wind noise exceeds the threshold, the system selects a transfer function designed for high-noise conditions rather than shutting down, allowing continued noise cancellation in the engine frequency range despite the presence of high-level wind noise.
Data Source
AI summary
An apparatus for improving the sound of a vehicle according to one embodiment of the present invention, may comprise: a window open/closed detection sensor for detecting the open/closed state of a window of the vehicle; a car door open/closed detection sensor for detecting the open/closed state of a car door of the vehicle; a speed sensor for measuring the speed of the vehicle; a microphone; a memory; and a processor for adjusting a coefficient of an adaptive filter used for an engine order cancellation (EOC) function, on the basis of the opened degree of the window and the speed, when the car door is closed, the window is open, and the magnitude of noise inputted to the microphone is less than or equal to a threshold magnitude.