Adaptive Tap Detection in ANR Headphones
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Solution Overview
Problem
Conventional acoustic noise reduction (ANR) headphones lack a reliable method to distinguish between acoustic noise and user-initiated taps, leading to inaccurate detection and control of audio system functions.
Innovation Solution
The implementation of a method that senses the current responsive to pressure changes in the ear canal, using an adaptive threshold based on peak values to differentiate between taps and noise, allowing for reliable detection and control of audio system modes and attributes through tapping on the headphones or ear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional acoustic noise reduction headphones use a fixed threshold to detect taps, then the detection method is simple, but the accuracy of distinguishing taps from acoustic noise is poor
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed threshold to an adaptive threshold that dynamically adjusts based on environmental conditions. The threshold is continuously updated using peak values from recent measurements, allowing the system to adapt to varying acoustic environments and improve tap detection accuracy without requiring manual recalibration.
Solution Approach 2:
The patent implements feedback by using the detected peak values to continuously update the threshold. The system monitors the current and previous peak values, compares them to determine if a tap occurred, and then uses this information to adjust the threshold for future detections, creating a closed-loop adaptive system.
2Ease of operation
If physical buttons are used for controlling audio system modes, then the control mechanism is reliable, but the ease of operation is reduced due to accessibility issues and distractions
Solution Approach 1:
The patent replaces the mechanical button system with a tap-based control mechanism. Instead of requiring physical button presses, the system detects taps through acoustic pressure changes in the ear canal, substituting mechanical interaction with acoustic sensing to improve ease of operation while maintaining control reliability.
Solution Approach 2:
The patent introduces an intermediary mechanism by using the ear canal acoustic environment as a medium for control. The tap gesture is transmitted through the ear canal to the microphone, allowing control without direct mechanical contact with buttons, thus improving accessibility while maintaining reliable detection through the adaptive threshold system.
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
Enables precise detection of user taps to change audio system modes and attributes without misinterpreting noise, providing a user-friendly control mechanism that avoids the need for physical buttons, especially beneficial in scenarios like aircraft use where button access can be distracting.
Implementation Method 1
The ANR module is coupled to the microphone for generating a noise cancellation signal to cancel noise detected by the microphone
Implementation Method 2
A current that is responsive to a pressure change in the ear canal and provided to the ANR module is sensed
Data Source
AI summary
Described are a headphone and a method for controlling an audio system. The method includes tapping a headphone or head of a user to cause an acoustic pressure change in an ear canal of the user wherein the ear canal is sealed by an acoustic noise reduction (ANR) headphone having an ANR module. A current provided to the ANR module is sensed. A peak value of the sensed current is determined and compared to a value of an adaptive threshold to determine if a tap occurred. If a tap is determined to have occurred, an updated value for the adaptive threshold is determined based on the peak value and at least on prior peak value. A mode of operation of the audio system or an attribute of an audio input signal may be changed in response to the determination of an occurrence of a tap.