多触点抗强光干扰红外触摸屏的设计与验证

【作者】 张宏伟；

【导师】 黄子强；

【作者基本信息】 电子科技大学 ， 光学工程， 2009， 硕士

【摘要】 触摸屏作为一种交互式输入设备,因其具有操作简单,使用灵活的特点得到了广泛的应用。红外触摸屏是其中的一种,它是在屏幕四边放置红外发射管和红外接收管,微处理器控制驱动电路依次接通红外发射管并检测相应的红外接收管,形成横竖交叉的红外光阵列。它无需薄膜,光透过率为100%,而且不受电流、电压和静电干扰,适宜恶劣的环境条件。但受到的外界光干扰很大,容易造成误操作,并且在应用中的分辨率不高。以上两点缺陷严重的制约了它在触摸屏市场上的发展,尤其是在机载显示领域中。同时多触点的电阻触摸屏、电容触摸屏相继问世,更是给红外触摸屏的性能提出了更高的要求。为了实现以上红外触摸屏的待改善的性能,本论文基于红外触摸屏的原理设计并开发出一种多触点、抗强光干扰、高分辨率的红外触摸屏,并对设计方案进行了验证。本论文中微处理器实时控制红外发射和接收模块,保证红外发射管与红外接收管一一对应,并将接收到的光强信号量化分级,利用触摸物的位置与接收的红外光信号强度一一映射的关系,实现了高分辨率,可达到2048×768;通过在红外接收管前安装对传播方向敏感的光准直沟道尽可能的削弱了外界光的干扰,同时根据检测不同状态下的光强信号,确定每对红外管的光强域值,并实时的调节该域值响应外界光的变化,通过以上的处理红外触摸屏可以在17600勒克司的环境光下正常工作,将触摸屏的抗强光干扰能力提高了近3倍;在检测完所有的触摸点位置后,判断手指触摸的先后,剔出其中的虚伪触摸点,得到精确的触摸位置,实现了红外触摸屏的多触点;通过VC编程,研究了在Windows下实现鼠标的平滑化处理、定位、单击、双击、抬手,以及指定调节亮度的区域的算法。更多还原

【Abstract】 Touch screen as an interactive input device is extensively applied because of the simple operation and the flexible feature. Infrared touch screen is one of them. Infrared transmitters and infrared receivers are placed on the screen edges and microprocessor driving circuit is used to connect to the infrared transmitters and check the appropriate infrared receivers, which forms the infrared crossed arrays. Films are not needed, and the optical transmission is 100 percent. The current, voltage and electrostatic interference can make no difference on the screen, and so it is suitable for harsh environmental conditions. But the infrared touch screen is greatly affected by the light interference, causing the accidental operation easily. Meanwhile it is not high in the resolution of application. These two points above seriously constraint it in the market, especially in the development of applications in airborne human-computer interaction. At the same time, multi-points resistive touch screen and capacitive touch screen have gradually come into the market, which makes the performance of the infrared touch screen require much more.Based on the improvement of the infrared touch screen above, the design of the multi-touch, anti-intense interference, high resolution infrared touch screen design is presented and proved in the dissertation.In this dissertation, the emission module and the receiving module are controlled by the microprocessor chip to make the infrared receivers keep accord with the infrared transmitters. And the light signal received is graded. According to the relationship between the position of the touch and the integrity of the light signal, the high resolution is achieved, 2048 by 768; in front of the infrared receiver, the light collimation channels sensitive to the direction of propagation of light are installed to weaken the optical jamming around the environment. At the same time, according to detecting the light signal received in the different state, the threshold of the touch is determined. The threshold is adjusted real-timely to response to the change of the light around the environment. By the processing above, touch screen can normally work in the 17600 lx light and the ability of the anti-highlight jamming can nearly be enhanced by 3; after testing all the positions of the fingers touch, the false touch points are removed to get the exact coordinates and get the multi-touch infrared touch screen. With the programming of VC, the algorithm which makes the mouse smoothing process, orientation, click, double-click, identifies hand movements and appoints the area where the brightness will be modulated is researched.更多还原