Acoustic Touch Detection Noise Reduction
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Solution Overview
Problem
Electronic devices with touch-sensitive surfaces face challenges in accurately detecting touch events in noisy environments due to noise pollution, and existing methods are vulnerable to unauthorized access of touch location information, particularly when the signal-to-noise ratio is low.
Innovation Solution
The implementation of a filtering unit within the electronic device that utilizes spurious acoustic signal generating devices and their parameters to improve the signal-to-noise ratio of acoustic signals, while also masking touch event contributions with spurious signals, making it difficult for unauthorized persons to determine touch locations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If acoustic sensors are used to detect touch events on the touch sensitive surface, then the device can detect touch locations using acoustic signals, but noise pollution from the environment and internal device components degrades the signal-to-noise ratio and reduces detection accuracy
Solution Approach 1:
The patent applies noise cancellation technology that uses reference signals from internal acoustic sources (speaker, vibration motor, fan) to generate anti-noise signals. These reference signals, which would normally be considered harmful noise, are instead utilized as the basis for creating compensating signals that actively cancel the noise in the acoustic sensor output, thereby improving touch event detection accuracy in noisy environments
Solution Approach 2:
The patent introduces a noise cancellation unit that acts as an intermediary between the acoustic sensor and the touch event determination unit. This intermediate processing stage receives both the raw acoustic sensor signals and reference signals from internal components, processes them through noise cancellation algorithms, and outputs cleaned signals to the touch event determination unit, effectively mediating the harmful noise effects
2Measurement precision
If acoustic signatures are stored in databases for touch location determination, then touch interactions can be analyzed accurately, but unauthorized persons can secretly attach sensors to the interface to identify confidential information like pin codes
Solution Approach 1:
The patent intentionally introduces spurious acoustic signals from internal device components (speaker, vibration motor) that mask the acoustic signatures generated by user touch interactions. These spurious signals, which would normally interfere with detection, are instead used to conceal confidential information such as pin codes from unauthorized eavesdroppers, while the noise cancellation unit ensures legitimate touch detection remains accurate by removing only the predictable internal noise
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
This approach enhances the accuracy of touch event detection and improves the confidentiality of user interactions by effectively reducing noise contributions and protecting sensitive information from unauthorized access.
Implementation Method 1
One of the existing technologies analyses acoustic signals, which can be observed after a touch event has occurred on a surface to determine the location of the touch event. This technology has the advantage that actually any material capable of transmitting acoustic waves can be used as an interface.
Implementation Method 2
a filtering unit configured to improve the signal-to-noise ratio of the acoustic signal based on one or more reference signals provided by one or more spurious acoustic signal generating devices of the electronic device
Data Source
AI summary
The invention relates to an electronic device with a touch sensitive surface comprising: a sensing means for capturing an acoustic signal, a touch location determining unit configured to determine the location of a touch event on the touch sensitive surface based on the acoustic signal. To improve the reliability of the touch localization process, the device further comprises a filtering unit configured to improve the signal-to-noise ratio of the acoustic signal based on one or more signals provided by one or more spurious acoustic signal generating devices of the electronic device and/or based on one or more parameters of the one or more spurious acoustic signal generating devices of the electronic device. The invention also relates to a corresponding method. The invention furthermore relates to a method for improving the confidentiality of a user input.