le travail à l'écran de visualisation work with display units

COMPUTERIZED METHOD FOR ANALYZING SHARPNESS AND TREMBLING OPCHARACTERS ON VDT SCREENSTITLE: Evolution of SpeechViewer: A Tool forRehabilitationKatsuo Nishiyama, Department of Preventive Medicine, ShigaUniversity of Medical Science, JapanPRESENTER:Robert B. Mahaffey, Ph.D.University of North Carolinaat Chapel HillThe aim of the study was to develop the method to analyze thesharpness and trembling of characters independently. Theperceived blur of characters on VDT screens is thought to consistof the sharpness of the characters on each frame and thecontinuous trembling of the position of the same characters froma frame to the another. The former relates to the goodness ofdisplay screen surface and focusing of elctron beam and thelatter relates to the stability of deflection of electron beam.It is interesting to study the psychophysiological effect of thecombination of these two factors. Also the independent evaluationof these factors may be useful in order to improve displayquality on the course of electronic circuit design and qualitycontrol in manufacturing process of VDTs.Measuring system was configured with modular area camera(MC9128-1, EG&G Reticon) , contro11er(RS-9100, Tokyo Electron), videomonitor, personal computer(PC-9800 VX, NEC) with CRT display andXYZ stage. Full frame rates from 25 up to 380 frames/second canbe achieved with the camera. The frame start and reset of thecamera can be controlled by external clock signal. Saturationexposure is 0.155 uj/cm 2 . The camera was controlled by PC-9800 VXthrough RS-9100. The number of gradation is 256. 64(optionally upto 512) frames from the camera can be stored in the frame memoryof RS-9100 and then processed by PC-9800 VX.ABSTRACT:Individuals with speech disorders are inherently limited in oneof man's unique and fundamental capabilities : verbalcommunication. A clinical tool for speech language pathologistsand teachers of the deaf has emerged from IBM's Special NeedsSystems Division that helps people improve their speech. Thetool, SpeechViewer, computes bold graphic displays and auditoryplayback to provide feedback to the speaker. It helps thespeaker to gain control over speech patterns.This product was begun ten years ago as a research project inIBM's Paris Scientific Center. With input from teachers of thedeaf and speech pathologists in 29 countries, the research toolhas evolved into a practical clinical tool. The project beganbefore the PC was a reality and has developed as computertechnology has progressed. The final product is the result ofstrong liaison between clinicians and developers. Thepresentation will highlight this research and developmentprocess.KEYWORDS:Disabilities, VDU Technology, Speech disordersContour lines for equal luminance for a character of each framewere got by PC-9800 VX in order to evaluate the sharpness. Alsothe magnitude and direction of deviation of a certain levelcontour line from a frame to another one were calculated toevaluate the trembling of a certain character.In the laboratory studies, the above indexes were measured fordifferent VDT types such as monochrome/colour CRT, LC-display,and plasma display from different manufacturers.The result showed that it was necessary to improve furthermore• the sensitivity of the camera because of low luminance of thecharacters on CRT type screens.KEYWORDS: Vision, sharpness, blur, methodologyTEV 1989 DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE • MONTRÉAL . SECOND INTERNATIONAL SCIENTIFIC CONFERENCE - WWDU 1989152TEV 1989 — DEUXIÈME CONFÉRENCE SCIENTIFIQUE INTERNATIONALE •— WWDU 1989MONTRÉAL • SECOND INTERNATIONAL SCIENTIFIC CONFERENCE153