| 摘要 |
A touch detection using wavelet algorithm for detecting touches on a surface by receiving acoustic waves generated by the touch and performing signal analysis on these acoustic waves using wavelet transformation where the storage requirement for reference signal is reduced. The inventive device includes a substrate that can be any material which is capable of propagating acoustic waves, transducers that detect the acoustic waves generated by the touch on the screen, a controller that implements the wavelet algorithm and software that incorporates wavelet algorithm. The substrate can be built from any material that is capable of propagating acoustic waves. The size of the substrate is not limited to a certain size. The sensitivity of the controller is determined and adjusted by the algorithm based on the size of the substrate. This is an adaptive sensitivity control determined by the size of the substrate. Transducers can be either piezo transducers or any other type that can detect acoustic waves generated by the touch on the substrate. The resonance frequency of these transducers can be within the sound frequency range. The sensitivity of the controller is determined based on the resonant frequency of these transducers used to detect acoustic waves. The controller is the device that accepts inputs from those transducers that are placed on the substrate. These signals are converted to digital signals by means of analog to digital converters on the controller board. These signals are applied to a microcontroller circuit on the controller. The microcontroller has a firmware code that is stored in the ROM area. This code implements the wavelet algorithm to characterize and detect the touch location. The location that is calculated by the controller is communicated to host computer. A driver that resides in the host computer receives the touch coordinate locations from the controller and communicates the location with the operating system. If the controller is not performing the wavelet algorithm then the software will be performing the wavelet algorithm.
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