基于计算机的多媒体抢答系统设计

介绍了一款利用计算机并口和键盘芯片制作的抢答器,该系统成本低廉,制作方便,可扩充性强,可以作为学生的课外活动或毕业设计,具有很强的实用性。     

Acceptance of the adjustable keyboard

The acceptance of a split keyboard with a user-adjustable angle (adjustable keyboard) and its impact on postural discomfort and general comfort of users was tested in a comparative laboratory experiment with 26 typists as subjects. The comparison was made with a standard keyboard. The results were interpreted using the findings of an earlier field study with another split keyboard with a fixed angle between the halves of the device. Both split keyboards improved postural comfort; however, the period of familiarization was much longer with the fixed-angle split keyboard. Since the adjustable keyboard allows a change, in the angle from 0 to 30^°, a person's posture can be adopted on a step-by-step basis. Thus, the new adjustable design has much better prospects of being accepted in practice than former attempts where the value was more academic than practical. The analysis of throughput and errors, under self-determined angles of the test object and with an angle comparable with those of fixed-angle split keyboards, reveals that users in work situations are not likely to accept fixed-angle split keyboards (30°) since throughput is substantially reduced during the long period of familiarization, accompanied by a substantial increase in errors. The results of this study confirm the assumption that new adjustable split keyboard design, once accepted by the users, may improve postural comfort, general comfort, and reduce fatigue. These effects could be demonstrated both in a short-term experiment and a long-term field study. The basic design feature of the adjustable keyboard, adjustability, is in agreement with the conclusions of recent studies on the introduction of ergonomically designed keyboards.     

Integrated text entry from power wheelchairs

Power wheelchair joysticks have be used to control a mouse cursor on desktop computers, but they offer no integrated text entry solution, confining users to point-and-click or point-and-dwell with on-screen keyboards. On-screen keyboards reduce useful screen real-estate, exacerbating the need for frequent window management, and impose a secondary focus of attention. By contrast, we present two integrated gestural text entry methods designed for use from power wheelchairs: one for use with joysticks and the other for use with touchpads. Both techniques are adaptations of EdgeWrite, originally a stylus-based unistroke method designed for people with tremor. In a preliminary text entry study of 7 power wheelchair users, we found that EdgeWrite with a touchpad was faster than the on-screen keyboard WiViK with a joystick, and EdgeWrite with a joystick was only slightly slower. These results warranted a multi-session comparison of text entry with EdgeWrite and WiViK using joysticks and touchpads, in which we found touchpads faster than joysticks, and EdgeWrite faster than WiViK with both devices after initial learning periods.     

一种基于虚拟键盘图像坐标变换的几何失真校正方法

虚拟键盘图像采集过程中出现的几何失真情况会直接导致按键落点识别错误.针对这一问题,提出一种基于数字图像坐标变换的几何失真校正方法.该方法针对矩形虚拟键盘,用几何坐标变换的方法,分别对拍摄装置垂直俯拍时出现的倾斜失真情况和水平侧拍时出现的透视失真情况作了校正.同时提出对图像使用二分法提取有效校正区域,从而减少计算量、提高处理速度.经实践对比与分析,该方法在准确率与效率方面均体现了可行性.     

单片机矩阵式键盘的设计

由于不同的单片机提供的片内外资源不同,所以在进行键盘扩展时其硬件电路也有所不同。以C8051F020单片机为例,介绍键盘采用中断扫描的工作方式实现数字键和功能键的输入。     

基于ARM的DCS专用工业键盘研究与实现

工业控制现场中的分散控制系统(DCS)需要特定的DCS操作员键盘对其进行控制。研究了基于ARM微处理器的DCS专用工业键盘,设计了具有USB2.0通信协议的标准HID类键盘接口程序以及具有标准PC键盘和DCS功能扩展键盘功能的键盘任务处理程序。实验结果表明,设计合理、系统稳定可靠,能满足工业现场环境的需要。     

可键控的高频信号发生器的设计

介绍了一种键控式的采用单片机对高频函数发生电路进行程序控制的高频信号发生器的设计方案。此方案能产生方波、正弦波和三角波等信号;采用数字频率合成器,使输出信号频稳度和晶体振荡器的相当;并用键盘设置波形和频率,由LED显示。输出信号的频率分成1 MHz~16 MHz和8 kHz~999 kHz两挡。     

L82C79可编程键盘／显示控制器的研制

本文介绍了Ｌ８２Ｃ７９的片内资源，以及设计过程中遇到的一些问题和处理方法。     

Backlit Keyboard Inspection Using Machine Vision

A robust system for backlit keyboard inspection is revealed. The backlit keyboard not only has changeable diverse colors but also has the laser marking keys. The keys on the keyboard can be divided into regions of function keys, normal keys, and number keys. However, there might have some types of defects:incorrect illuminating area, non-uniform illumination of specified inspection region (IR), and incorrect luminance and intensity of individual key. Since the illumination features of backlit keyboard are too complex to inspect for human inspector in the production line, an auto-mated inspection system for the backlit keyboard is proposed in this paper. The system was designed into the operation module and inspection module. A set of image processing methods were developed for these defects inspection. Some experimental results demonstrate the robustness and effectiveness of the proposed system.     

触摸屏按键特征因素对键盘输入操作可用性的影响

目的研究三种按键特征因素(即按键大小、间距和形状)对触摸屏输入可用性的影响。方法本研究结合人因实验和分析,采用5按键大小×3间距×3形状的组内设计,对触摸屏输入可用性(即输入绩效和使用偏好)进行实验测试,被试为15位在校大学生,采用重复测量的方差分析处理数据。结果按键大小、间距和形状对输入绩效均有显著影响;按键大小和间距、按键大小和形状之间存在显著交互作用;用户偏好可能产生较优绩效的按键设计方式。结论三种按键特征因素的不同设计方式对触摸屏输入的可用性有显著影响。