Vehicle Audio Feedback Detection Using Acoustic Acuity Trends
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Solution Overview
Problem
Existing hands-free communication systems in vehicles suffer from acoustic feedback issues, which can cause discomfort and safety hazards due to unpredictable software faults and resource limitations in automotive computers, necessitating a simple and resource-efficient detection and mitigation method.
Innovation Solution
A method involving computation of an acoustic acuity indicator for successive audio frames, detection of monotonic increase in the indicator for a predetermined time, and application of a resolution strategy such as attenuation or system reset to address acoustic feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If ECNR or AEC techniques are employed to reduce acoustic feedback, then acoustic feedback is reduced, but device complexity increases and reliability decreases due to software faults and resource limitations
Solution Approach 1:
The patent extracts the feedback detection function from the complex ECNR/AEC system and implements it as a separate, simpler mechanism using acoustic acuity indicator. This allows feedback detection without requiring the complex echo canceller to be fully functional, thereby reducing device complexity while maintaining feedback reduction capability.
Solution Approach 2:
The system uses the acoustic acuity indicator to automatically detect feedback conditions and trigger resolution strategies without requiring complex processing or external intervention. The indicator self-evaluates the feedback state based on high-frequency energy ratios, enabling the system to serve itself in detecting and responding to feedback issues.
2Device complexity
If simple detection method is used to reduce device complexity, then device complexity decreases, but measurement precision of acoustic feedback detection may be insufficient
Solution Approach 1:
The patent applies local quality by focusing the detection metric on a specific frequency range (high frequencies) rather than analyzing the entire audio spectrum. The acoustic acuity indicator specifically measures the ratio of high-frequency energy to total energy, providing precise feedback detection in the critical frequency band where feedback is most problematic, while avoiding the complexity of full-spectrum analysis.
3Object-affected harmful factors
If attenuation is applied to reduce acoustic feedback, then acoustic feedback is reduced, but user experience deteriorates due to noise in audio communication
Solution Approach 1:
The patent implements dynamic attenuation by adjusting the attenuation level based on the detected acoustic feedback strength and persistence. The system applies stronger attenuation when feedback is severe and weaker attenuation when feedback is mild, allowing the system to adapt to different feedback conditions and maintain user experience while effectively suppressing feedback.
Solution Approach 2:
The system uses the acoustic acuity indicator as feedback to continuously monitor the feedback condition and adjust attenuation accordingly. This closed-loop feedback mechanism ensures that attenuation is applied only when and where needed, preventing unnecessary attenuation that would degrade user experience during normal operation.
Data Source
AI summary
A method for detecting acoustic feedback in a vehicle audio system including at least one microphone and one loudspeaker. The method includes the steps of computation of an acoustic acuity indicator for each frame of a plurality of successive audio frames captured by the microphone, detection of acoustic feedback when the indicator increases monotonically for a predetermined length of time, and application of a resolution strategy when acoustic feedback is detected.Buchanan