基于互相关解调算法的抗强光红外触摸单元的研究与验证

发布时间：2018-01-09 05:07

本文关键词：基于互相关解调算法的抗强光红外触摸单元的研究与验证　出处：《电子科技大学》2014年硕士论文　论文类型：学位论文

【摘要】：随着信息化进程的不断加深,人机交互平台也向着越来越人性化的方向发展。自从触摸屏技术问世以来,触摸屏凭借着操作简单,使用灵活,携带便捷等特点发展至今,已经渐渐取代鼠标,写字板,键盘等传统硬件输入设备,成为人们日常生活中不可或缺的一部分。红外触摸屏作为触摸屏的一个研究分支,靠着自身的诸多优势从众多触摸屏中脱颖而出。红外触摸屏由于是通过遮挡红外光的方法来判断触摸点位置,无需在触摸屏上附加薄膜,透过率极高,因此有着极强的抗电磁静电干扰能力,非常适合于在高空以及电子干扰强的恶劣环境中作业。但由于红外触摸屏是通过发射接收红外光进行工作,对外界环境光照的变化比较敏感,在有外界强光照的条件下使用红外触摸屏会受到极大干扰,导致红外接收管接收到的光强发生异常,从而引起误动作。本文针对红外触摸屏的强光干扰问题,从红外触摸屏的工作原理以及电路设计方面进行深入研究,对目前几种常见的红外抗强光方法进行分析比较,提出了一种基于互相关锁相放大解调技术的新算法以及抗强光红外触控单元设计。本文采用高频红外光的发射与接收,利用PSOC5可编程片上系统对调制光进行AD转换与数字移相,以锁相放大方式滤除太阳光的干扰频段分量,实现了红外触控屏的抗直接照射的阳光干扰的方法与验证结果。此外,通过改进了锁相放大器的解调算法,去掉了传统的锁相放大后级所必须的滤波电路,使电路更加简洁、可靠。在实现抗强光干扰红外模块的设计过程中,先通过对互相关锁相放大解调技术新算法的理论验证证明总体设计方案的可行性,再通过硬件电路实验验证其有效性,最后完成整体数字电路设计测试其抗强光性能。之后将抗强光干扰数字电路加入红外触控单元的整体设计,结合对红外触摸信号发生模块分析以及红外发射、接收、控制模块技术,设计出基于互相关锁相放大选频的抗强光干扰红外触控单元。通过硬件平台实验证明,采用新型锁相放大技术能达到很好的抗强光效果,选频Q值能达到145.985,比起未经改动的锁相放大抗强光效果提高了9倍,并且能在环境光强50000lux下正常工作,很大程度下滤除了外界光的干扰,实现抗强光干扰目的。
[Abstract]:With the continuous deepening of the information process, the human-computer interaction platform is also towards the direction of more and more humanized. Since the advent of touch screen technology, touch screen with simple operation, flexible use. The characteristics of portable and convenient development have gradually replaced the traditional hardware input equipment such as mouse, tablet, keyboard and so on. As an indispensable part of people's daily life, infrared touch screen is a research branch of touch screen. The infrared touch screen has a high transmittance because it can judge the position of the touch point by blocking the infrared light, so it does not need to attach thin film to the touch screen. Therefore, it has strong anti-electromagnetic static interference ability, which is very suitable for working in high altitude and strong electronic interference environment. However, the infrared touch screen works by transmitting and receiving infrared light. It is sensitive to the change of external environment illumination. Using the infrared touch screen under the condition of strong external illumination will be greatly interfered, resulting in abnormal light intensity received by the infrared receiver. In this paper, the working principle and circuit design of the infrared touch screen are studied in detail, aiming at the problem of the strong light interference of the infrared touch screen. Several common infrared anti-glare methods are analyzed and compared. This paper presents a new algorithm based on mutual correlation phase-locked amplification and demodulation technology and the design of anti-strong light infrared touch control unit. In this paper, high frequency infrared light is used to transmit and receive. The modulated light is converted by AD and digital phase shift by PSOC5 programmable chip system, and the interference band component of solar light is filtered by phase-locked amplification. In addition, the demodulation algorithm of the phase-locked amplifier is improved, and the filter circuit necessary for the stage after the phase-locked amplifier is removed. Make the circuit more concise and reliable. In the design process of the infrared module against strong light interference, the feasibility of the overall design scheme is proved by the theoretical verification of the new algorithm of mutual correlation phase-locked amplification and demodulation technology. Finally, the whole digital circuit design is completed to test its anti-glare performance. After that, the anti-interference digital circuit is added to the whole design of infrared touch control unit. Combined with the analysis of the infrared touch signal generation module and the infrared transmitting receiving and controlling module technology the infrared touch control unit against strong light interference is designed based on the mutual correlation lock phase amplification and frequency selection. The new phase-locked amplification technique can achieve a good anti-glare effect. The Q value of frequency selection can reach 145.985, which is 9 times higher than that of unmodified phase-locked amplification. And it can work normally under the environment light intensity 50000lux, filter out the interference of the outside light to a great extent, realize the purpose of resisting the strong light interference.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN873;TN219

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