基于STM32和FPGA的光学多点触摸屏的设计与实现

发布时间：2019-04-23 11:56

【摘要】：随着社会的发展和科学技术的创新，人们对于人机交互的要求越来越高，传统的鼠标，键盘等交互方式甚至于单点触摸已经不能满足用户，在这样的情况下，多点触摸技术应运而生。多点触摸技术是在单点触摸的基础上发展而来的，该技术可以使用户可同时控制的操作点扩展到多个，甚至多个用户同时使用。它使得操作更灵活，给用户带来一种前所未有的体验。本文研究了一种基于STM32单片机多点触摸的设计方法，对实现多点触摸的坐标运算，HID设备通信等关键内容进行了研究，并在FPGA上实现CORDIC算法，为坐标运算打下了基础。主要研究内容有以下几个方面： (1)采用成本比较低的数字图像传感器CMOS作为图像采集器件，利用摄像头交汇定位原理推导出坐标运算的公式，从而进行坐标运算的算法设计，对触摸点进行准确的定位，并在STM32单片机上实现。 (2)深入研究了CORDIC算法的原理，并对传统的CORDIC算法进行了改进，在此基础上利用FPGA实现了正弦函数与反正切函数的计算，此后对改进的算法进行仿真和结果的误差分析，协助STM32单片机进行触摸坐标的运算。 (3)利用STM32芯片进行USB接口电路的设计，研究了HID类设备的USB协议，包括USB设备的描述符、枚举过程等，同时研究关于多点触摸的微软白皮书。在STM32单片机上实现USB的编码测试，并进行实验验证。将STM32单片机模拟成HID多点触摸设备，搭载Windows系统的上位机进行通信，将触摸点信息传给Windows操作系统,以便Windows系统执行下一步操作。本文所设计的触摸屏系统硬件成本低，，在尺寸需求增大的情况下成本增幅不大，因此在大尺寸触摸屏上体现出来的性价比就比较高，并且在Window系统中能够实现即插即用，非常方便，具有一定的实用价值。
[Abstract]:With the development of society and the innovation of science and technology, people have higher and higher requirements for human-computer interaction. Traditional interactive methods such as mouse, keyboard and even single-point touch can not satisfy the user, under such circumstances, Multi-touch technology emerges as the times require. Multi-touch technology is developed on the basis of single point of touch. This technology can extend the operation points that users can control at the same time to multiple or even multiple users at the same time. It makes operations more flexible and gives users an unprecedented experience. In this paper, a design method of multi-touch based on STM32 single-chip microcomputer is studied. The key contents such as coordinate operation of multi-touch and communication of HID equipment are studied, and CORDIC algorithm is realized on FPGA, which lays a foundation for coordinate operation. The main research contents are as follows: (1) the digital image sensor CMOS, which has low cost, is used as the image acquisition device, and the formula of coordinate operation is deduced by using the principle of camera intersection and positioning. As a result, the algorithm of coordinate operation is designed, the touch point is located accurately, and it is realized on STM32 single chip microcomputer. (2) the principle of CORDIC algorithm is deeply studied, and the traditional CORDIC algorithm is improved. On this basis, the calculation of sine function and anti-tangent function is realized by FPGA. After that, the improved algorithm is simulated and the error analysis of the results is made. Assist STM32 single-chip microcomputer in the operation of touch coordinates. (3) the USB interface circuit is designed by using STM32 chip. The USB protocol of HID device is studied, including the descriptor of USB device, enumerating process and so on. At the same time, the Microsoft white paper about multi-touch is studied. The coding test of USB is realized on STM32 single chip computer, and the experiment is carried out. The STM32 single chip microcomputer is simulated as a HID multi-touch device, the upper computer with Windows system is used to communicate, and the touch point information is transmitted to the Windows operating system, so that the Windows system can perform the next operation. The hardware cost of the touch screen system designed in this paper is low, and the cost increase is not big when the size demand increases. Therefore, the ratio of price to performance on the large size touch screen is relatively high, and the plug and play can be realized in the Window system. It is very convenient and has certain practical value.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TP334.3

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