A0模态兰姆波触控屏声指纹库质量评价方法

影响A₀模态兰姆波触控屏性能的核心要素是声指纹库质量,基于曼哈顿距离统计和分析方法研究了声指纹库的质量评价及优化问题。首先,采用有限元方法仿真建立了900种激励-接收节点布局方案对应的触控介质声指纹库;其次,提出了曼哈顿距离图谱及其频次分布图谱的构建方法,利用图谱特征(最小非零频次和峰值分布区间的左临界点)和频次直方图的加权量化指标,对声指纹库质量进行评价,并对激励-接收节点布局方案进行了优选;最后,分析了激励信号对声指纹库质量的影响,相比窄带猝发(Tone burst)信号激励形式,宽频带的线性调频(Chirp)信号激励条件下获得的声指纹库质量明显更优。该研究为超声兰姆波触控屏声指纹库质量的优化提供了基础方法借鉴。

Evaluation method of acoustic fingerprint database for A0 modal Lamb wave touchscreen

The core factor affecting the performance of A₀ modal Lamb wave touch screen is the quality of the acoustic fingerprint database.The quality evaluation and optimization of the acoustic fingerprint database are studied through statistical and analytical method of Manhattan distance.Firstly,900 layout schemes of excitation-receiving sensors are simulated with finite element model and 900 corresponding databases are collected.Then,a set of nephograms of Manhattan distance and its frequency distribution for each database are constructed.The quality of each database is evaluated according to the features of the nephogram set and the weighted sum values of the frequency histogram.The layout scheme of excitation-receiving sensors is optimized according to the database quality.Finally,the influence of excitation signal on the quality of acoustic fingerprint database is analyzed.Compared with the tone burst excitation signal,the broadband chirp signal can significantly improve the database quality.The above researches provide a basic method to optimize the quality of acoustic fingerprint database for Lamb wave touch screen.