Positive display polarity is advantageous for both younger and older adults

The effect of display polarity on visual acuity and proofreading performance was investigated for younger and older adults. An advantage of positive polarity (dark characters on light background) over negative polarity (light characters on dark background) was expected for younger adults, but the effects on older adults were ambiguous. Light scatter due to residues in the senescent lens and vitreous humour could reverse the typical advantage of positive polarity. However, age-related changes lead to a decline in retinal illuminance. Brighter positive polarity displays should help to compensate for this decline and, accordingly, lead to better performance than darker negative polarity displays. Participants conducted a visual acuity test with black optotypes on white background or white optotypes on black background and performed a proofreading task in the same polarity. A positive polarity advantage was found for both age groups. The presentation in positive polarity is recommended for all ages.

Practitioner summary: In an ageing society, age-related vision changes need to be considered when designing digital displays. Visual acuity testing and a proofreading task revealed a positive polarity advantage for younger and older adults. Dark characters on light background lead to better legibility and are strongly recommended independent of observer's age.     

The colours are not on the display: a survey of non-veridical perceptions that may turn up on a colour display

Designers and users of colour-coded visual displays may be confronted by puzzling artefacts that are produced by the physiological mechanisms of visual perception. In this review I shall describe a variety of such visual oddities, discuss their nature, and provide suggestions for dealing with them. The phenomena to be discussed are small-field tritanopia, peripheral colour vision, the Bezold-Brücke effect, the Helmholtz-Kohlrausch effect, the Abney effect, chromatic induction, assimilation, the McCullough effect, the ‘fluttering hearts’ phenomenon, chromatic aberration, and colour stereoscopy.     

The advantage of positive text-background polarity is due to high display luminance

Reading text from computer screens is better when text is printed in dark letters on light background (positive polarity) than when it is printed in light letters on dark background (negative polarity). An experiment is presented that tests whether this positive polarity advantage is due to the fact that overall display luminance is typically higher for positive than for negative polarity displays. To this end, text-background polarity and display luminance were manipulated independently. No positive polarity advantage was observed when overall display luminance of positive and negative polarity displays was equivalent. There was only an effect of display luminance, with better performance for the higher-luminance displays. This suggests that the positive polarity advantage is in fact due to the typically higher luminance of positive polarity displays. Readability of text presented on computer screens (e.g. on websites) is better when the overall display luminance level is high, as in positive polarity displays (dark letters on light background). Display polarity per se does not affect readability.     

Subjective reactions to misconvergence on a colour display

Subjective ratings of various degrees of misconvergence were obtained from subjects viewing text and graphics pictures on a 355 mm high-resolution shadow mask colour CRT display. The pictures were displayed in four secondary colours: white, yellow, turquoise (cyan), and pink (magenta). In commercial applications, user acceptance and satisfaction often present more stringent requirements for front-of-screen quality than do objective performance criteria such as legibility. In this case, it is expected that the picture quality would become unacceptable at lower levels of misconvergence than would cause it to be considered illegible. The results show a marked degradation in apparent quality of convergence as misconvergence increases from about 0.2 mm to about 0.5 mm. To obtain subjectively acceptable picture quality, misconvergence should be no more than about 0.3 mm and should be better than 0.2 mm over the majority of the screen. (The spot size of the display used was about 0.8 mm.) Textual and graphical pictures did not produce significantly different results.     

Effects of display method,number of message lines,and text colour on Chinese comprehension and subjective preferences for an LED display

This study investigated the effects of display method, number of message lines and text colour on comprehension performance and subjective preferences for reading Chinese on a light‐emitting diode display. The factors and levels studied were: two text display methods (rapid serial visual presentation ‘rapid serial visual presentation (RSVP)’ and paged view scrolling), four numbers of message lines displayed at a time (one to four lines) and three text colours (amber, green and red). The RSVP method resulted in higher comprehension scores than the paged view scrolling method, and the green text produced better comprehension score than amber or red. However, the paged view scrolling received better subjective evaluation ratings than the RSVP method. A multiline display was found to be superior to a single‐line display for both comprehension scores and subjective evaluations. The results here provide useful ergonomics recommendations for choice of appropriate display method and format setting for presenting Chinese messages on light‐emitting diode displays.     

基于StellarisWare的电梯轿内TFT LCD显示及触屏设计

应用StellarisWare图形库技术实现图形显示,以LPC2478 ARM7微处理器为控制核心,设计了一种由TFT-LCD显示及触摸屏组成的电梯轿内人机交互界面显示控制器。介绍了LVDS通信接口的TFT-LCD显示、触摸及外部存储器SDRAM的硬件设计和软件设计。测试结果表明,系统实现了触摸功能,获得清晰稳定的显示效果,性能可靠。     

基于ARM的TFT-LCD显示系统设计

随着信息技术的不断发展,LCD已逐渐发展成为重要的图形界面设备;针对目前许多设备对人机交互界面的应用需求,给出了一种嵌入式微处理器ARM9控制的,基于真彩色TFT型的LCD液晶显示系统;重点介绍了ARM芯片S3C2440的主要特点和WXCAT35液晶显示模块的基本使用方法,给出了S3C2440的LCD控制器与液晶显示模块的连接方法;并详细的分析WXCAT35的工作时序,确定像素时钟VCLK、行频HSF、场频VSF,以及介绍LCD控制器的结构,LCD控制寄存器的配置方法以及相关函数;经位图显示测试,所设计的软硬件符合要求,实现了ARM控制的液晶显示系统。     

Measured and perceived colour on cathode ray tubes

A study is outlined which indicates that the application of traditional colorimetry to CRT displays is not totally adequate. The findings may be interpreted as indicating that the measured colours of CRT displays are always more saturated than the colours perceived by the human eye.     

Selected colours for use on colour cathode ray tubes

This paper indicates the confusion existing between a number of colour standards before outlining how they may have been derived. All the standards are unable to deal with modern electronic displays. A computational procedure is described which enables new colour boundaries to be specified. A summary of data derived using the procedure is presented.     

Spatial contrast detection for colour patterns under selective chromatic adaptation

This paper reports the results of a fundamental study investigating the filtering characteristics of the colour mechanisms that encode spatial information. The shape of the contrast sensitivity function of the human visual system with red, green and blue stimuli was investigated under selective chromatic adaptation, and at eccentricities of 0°, 13° and 26°. The results are compared with those obtained with an achromatic test, at the same eccentricities. The band-pass character of the contrast sensitivity function is brought to light for the three selective chromatic adaptation states obtained. It is more pronounced in peripheral than in foveal vision, whatever the temporal frequency tested. The authors suggest an interpretation of the shape changes of the contrast sensitivity curves based on the neurological properties of achromatic and chromatic mechanisms. The functional exploration of the neurophysiological and optical properties of the visual system may be useful to display designers and users as far as the system efficiency for using colour as an information code is concerned.     

Calculating the perceptibility of monochrome and colour displays viewed under various illumination conditions

Results from a series of calculations which assist the display designer to assess the optimum colour or colours for use on a display device are presented. Plots are produced which indicate the principles which must be adopted in the evaluation of the relative importance of display luminance and colour when the device is to be viewed under both specific and widely differing illumination conditions.     

Application and experience of colour CRT flight deck displays

Colour CRT displays have the potential both to enhance the presentation of primary flight information and also to improve the interface between complex avionic systems and the flight deck crew. This paper describes research to explore this potential, and reports the opinions of a wide range of pilots who experienced such displays in the working environment.     

基于嵌入式系统的彩色液晶显示驱动控制

分析了TFT-LCD与PXA270内嵌的LCD控制器的基本原理与时序,根据它们的特点与时序要求,设计了TFT-LCD的硬件驱动接口电路,基于Linux-2.4.19内核设计了相应的驱动程序,软硬件在目标板上工作良好。该设计对于驱动TFT-LCD具有通用性,由于Linux驱动程序移植性强,因而该设计可适用于工业控制领域多种嵌入式系统。     

Computation of the resultant chromaticity coordinates and luminance of combined and filtered sources in display design

Display designers are confronted by many possible emitters, filters and reflectors which can be used in order to produce a display to be viewed under varied or various illuminations. Often it is not possible to evaluate the perceptual performance associated with various combinations of these components until the whole configuration is assembled. A program is described which allows the resultant chromaticity coordinates of combined and filtered sources to be computed. The program allows the designer of complex display systems to make an evaluation of perceptual performance prior to construction. Examples are given which illustrate the use of the program.     

基于嵌入式系统的彩色液晶显示驱动控制

分析了TFT-LCD与PXA270内嵌的LCD控制器的基本原理与时序。根据它们的特点与时序要求，设计了TFT-LCD的硬件驱动接口电路，基于Linux-2．4．19内核设计了相应的驱动程序，软硬件在目标板上工作良好。该设计对于驱动TFT-LCD具有通用性。由于Linux驱动程序移植性强，因而该设计可适用于工业控制领域多种嵌入式系统。     

FPGA的TFT-LCD真彩液晶屏显示控制

目前液晶屏的使用越来越广泛,TFT-LCD真彩液晶屏由于其良好的视觉效果,简便的控制方法在液晶屏使用市场中占有很大的空间,但是目前常用的TFT-LCD液晶屏主控芯片主要是单片机、STM32等,不能满足更进一步的研发需求,本文主要研究了FPGA驱动TFT-LCD液晶屏的方法,使用80并口控制芯片操作完成复杂的屏幕显示功能.     

S3C2410TFT—LCD显示的驱动程序设计

系统地介绍了S3C2410微处理器内置的LCD控制器功能与结构,TFT型彩色LCD显示的基本工作原理,LCD显示屏与微处理器的连接,通过编写S3C2410的LCD端口初始化及LCD初始化驱动程序,实现了LCD清晰稳定的显示。为汽车行驶记录仪中人机界面设计提供了很好的解决方案。     

Smaller pupil size and better proofreading performance with positive than with negative polarity displays

The ‘positive polarity advantage’ describes the fact that reading performance is better for dark text on light background (positive polarity) than for light text on dark background (negative polarity). We investigated the underlying mechanism by assessing pupil size and proofreading performance when reading positive and negative polarity texts. In particular, we tested the display luminance hypothesis which postulates that the typically greater brightness of positive compared to negative polarity displays leads to smaller pupil sizes and, hence, a sharper retinal image and better perception of detail. Indeed, pupil sizes were smaller and proofreading performance was better with positive than with negative polarity displays. The results are compatible with the hypothesis that the positive polarity advantage is an effect of display luminance. Limitations of the study are being discussed.     

Comparison of colour and black-and-white visual displays as indicated by bombing performance in the 2B35 TA-4J flight simulator

Ten highly qualified and experienced instructor pilots were tested with respect to bombing performance in the General Electric 2B35 full colour wide screen flight simulator. Half the pilots flew with colour first and then black-and-white and the other half with the reverse order. Repeated bombing runs were made and circular bombing errors obtained. Under the conditions of the study, no statistically significant differences were shown between performances in colour and those in black-and white.     

基于PXA255微处理器的液晶显示驱动设计

介绍了嵌入式微处理器PXA255及其集成的LCD控制器,分析了TFT-LCD的基本原理,结合它们的特点和工作时序,设计了LCD的硬件驱动接口电路．以Linux为嵌入式操作系统,设计了相应的驱动程序,能显示清晰稳定的画面,由于Linux平台下的驱动程序具有很强的移植性．因而该显示驱动不仅适用于楼宁自动化系统,略作变化后还可应用于其它嵌入式系统中。