【作者】 王刚；

【导师】 郭文明；

【作者基本信息】 北京邮电大学 ， 软件工程， 2015， 硕士

【摘要】 随着电脑功能的多样化,能够接入其中的外设也是多种多样的,触摸屏便是其中之一。作为一种使用非常方便的外设,触摸屏得到了广泛的使用。由于用户需求不断增多,操作复杂度也同时加大,多点触摸技术便应运而生。根据制作材料的不同,触摸屏分为电阻触摸屏、电容触摸屏、声波触摸屏和红外触摸屏等。红外触摸屏是可以支持多点触摸的仅有的几种触摸屏之一,因此,红外触摸屏成为了多点触摸技术的重要载体。使红外触摸屏能够在各类操作系统上使用具有十分重要的应用价值。作为连接硬件设备和软件的桥梁,驱动的作用是十分重要的,它决定着一套触摸设备能否正常地工作。对于多点触摸的研究已经有了一些先驱工作,并取得了一些的成功的经验。Windows操作系统主流版本已经可以通过HID协议支持多点触摸,因此,本文对驱动的主要研究平台是使用Linux内核的操作系统。研究工作分为两个阶段。首先,通过研究Linux内核中的触摸设备管理框架,找出Linux操作系统(Android除外)无法支持多点触摸的原因。通过在Linux内核通用的触摸屏驱动框架基础上添加TUIO驱动模块的方法,来实现Linux操作系统的多点触摸坐标传输功能,并且编写应用程序,实现对多点触摸屏的效果的模拟。其次,针对红外触摸屏在坐标传输过程中产生的“漂移”的现象,即触摸点和显示点坐标有较大偏移,需要设计一种能够有效控制误差的校准算法。本文尝试采用在仿射变换算法的基础上,对现有校准中获取采样点的方法进行改进。在校准过程中,Windows 8操作系统对触摸误差的要求是±1mm,并且,采样点通过率必须达到4%。因此,单纯使用打点法采集样本点并利用仿射变换算法进行校准已经不能满足精度要求。本文尝试提出两种坐标点采样改进方法,一种是将取值的方法由打点改进为划线,另一种是将屏幕分为多个区域进行多重校准,并通过实验验证改进后的方法可有效提高校准精度,并从操作性、复杂度和精度等方面对打点校准法、分区域多重校准法和划线法进行对比。本文针对坐标传输和校准两方面内容,对红外多点触摸屏驱动做出改进,达到了在Linux平台下实现红外触摸屏多点触摸操作的目的,并取得了良好的实验效果。更多还原

【Abstract】 With the diversification of computer functions,the peripherals that can access is also varied,touch screen is one of them.As a very convenient device,touch screen is widely used recently.Because of the increasing demand of user,the complexity of operation also increases,and the technology of multi-touch emerges as the times require.According to the differences of production’s materials,touch screen is devided into resistance touch screen,capacitive touch screen,sound-wave touch screen and infrared touch screen and so on.Infrared touch screen is one of the only touch screen which can support multi-touch,so it become the important carrier of multi-touch technology.It has very important application value,which infrared touch screen can be used in all kinds of operating systems.As a bridge of hardware and software,the function of driver is very important,and it decides whether a set of equipments can work properly or not.There have been some pioneering works about the research of multi-touch,and made much successful experience.For example,the main version of Windows operating system has supported multi-touch by HID protocol.So the main research platform of this paper is the operating system which use Linux kernel.The research work has been devided into two stages.Firstly,by studying the touch device management framework in the Linux kenel,we can find out the reasons why Linux operating system except for Android can’t support multi-touch.By adding TUIO driver module based on common touch screen driver framework in Linux kernel,we can achieve the function of multi-touch coordinate’s transfer of Linux operating system,and implement the simulation of multi-touch effect by writing a application procedure.Secondly,because the touch screen is easy to generate the phenomenon of touch points "drift",namely the touch points and the display points produce larger offset,the calibration algorethm should be designed to effectively control the drift errors.This paper attempts to improve the existing acquiring sampling point methods based on affine transformation algorithm.Affine transformation algorithm is one of the most widely-used methods in the touch screen calibration field.Because the affine transformation describes linear trasformation of two dimensional coordinates,which can realize the coordinate’s translation,rotation and scaling.This characteristic determins the affine transformation is very suitable for touch screen calibration.However,in the calibration process.the requirement for touch errors of Windows 8 is ±1mm and the pass rate of sample points must reach 4%.Therefore,simply using draw-point method has been unable to meet the requirement of accuracy.This paper tries to propose two improved calibration algorithm based on affine transform,one method use drawing lines instead of marking point,the other devide the screen into a plurality of areas to use multiple calibration.This two kind of methods can effectively improve the calibration precision.And we compare the draw-points calibration,multiple calibration and draw-lines calibration from operation,.complexity and accuracy.This paper integrated the above two parts into general infrared touchscreen driver in order to achieve infrared multi-touch operation and has expected results.更多还原