【作者】 朱晓乾；

【导师】 张秀彬；

【作者基本信息】 上海交通大学 ， 电力电子与电力传动， 2008， 硕士

【摘要】 人类社会生活日益追求便捷,硬币流通自动化技术的普遍应用就是一种很好的体现,如:自动售货机、投币电话机、游戏机、公交自动售票等都是一系列典型应用实例。然而,在人们的素养尚未得到普遍提高的情况下,使用假币冒充真币的现象时有发生,因此在硬币流通自动化设备中安装硬币鉴别装置成为不可或缺的技术手段。市面上现有硬币鉴别装置,由于硬件结构或软件算法的技术缺陷,往往存在成本高且辨别准确率不高的现象。本文详细阐述一种成本低、准确率高的硬币鉴别装置的设计及其实现技术。该装置具有学习功能,通过对市面上流通的所有版本硬币进行一次性学习,把真币的材质特征保存在EEPROM存储器里,以此作为鉴别硬币真伪的根据。另外该系统还具有在线升级功能,当市面上发行新版本的硬币时,只需再次启动学习功能,就能把新币种的材质特征也存入EEPROM存储器,从而增加对新币种的鉴别功能。该硬币鉴别装置包括:电磁传感器、信号调理电路、核心控制芯片、阀门开关电路。其中,电磁传感器形成涡流效应,这是对真假硬币实现准确鉴别的关键传感部件,信号调理电路将涡流效应模拟信号转换成数字信号,得到的数字信号通过核心控制芯片进行实时处理,阀门开关电路通过继电器控制阀门的开关,以接收或退出硬币。本文在提高准确率方面做出了多项改进措施,在硬件方面使用双频检测方法,在软件方面使用速度加权算法,从而使识别伪币的准确率达到98.3%以上。更多还原

【Abstract】 The modern human society pursues convenient, the common usage of coins’automatic circulation technology is a typical illustration. Such as automatic vendors, pay phones, arcade games and self-service ticketing buses are all the typical application examples. However, at the situation that people’s social moral are not universally advanced, the facts that using the fake coins as the real ones happen frequently. Hence, it becomes a necessary technology method to install coins detecting instrument in the coins automatic circulation facility. There are coins detecting instruments in the market at present already. Because of the technology disadvantages of hardware structures or the software arithmetic, it is common phenomenon that the costs are too high and the accuracies are too low.This paper will detailed expatiate a design and realization technology of low-cost and high-accuracy coin detecting instrument. This instrument has the function of learning. It can store the material characteristic of the real coins in the EEPROM memory through the learning of all kinds of coins in the market, and using this as the standard to judge the coins are real or fake. Otherwise, this system has the function that upgrade online. If there are new kinds of real coins in the market, we can just start the learning function and store the new coins’material characteristics in the EEPROM memory. Hence, add the function to detect the new kind of coins. This coins detecting instrument including electromagnetic sensor, signal adjusting circuit, kernel control chip and valve switch circuit. The electromagnetic sensor generates the eddy current effect,it is the key sensor part to realize the function of detecting the coins. The signal adjusting circuit transforms analog signals of eddy current effect into digital signals. The digital signals are processed by kernel control chip real time. The valve switch circuit is used to control the relay, determine to receive or reject the coins. This paper expatiate several improvement methods on increasing the accuracy. Through double-frequency detecting method on the hardware aspect, and speed-weighted arithmetic on the software aspect, making the accuracy of detecting the fake coin above 98.3%.更多还原