音声ブラウザご使用の方向け： SKIP NAVI ／ GOTO NAVI

Web Posted on: February 24, 1998

OPTIMIZING READING FOR VISUALLY IMPAIRED PEOPLE

James C. Bliss and Peter Young
JBliss Imaging Systems, 650 Saratoga Ave.,
San Jose, CA 95129 (408)246-5783

INTRODUCTION

In today's world one encounters information from a variety of sources, printed and electronic, and in wide range of type sizes, type fonts, colors, and formats with pictures and graphics imbedded in creative ways. While this variety makes the presentation more interesting and information more readily available for the viewer with normal eyesight, it can present problems for people with visual impairments.

For years magnification has been the main remedy to help people with low vision read. Optical magnifiers were the first generation of low vision assistive products and video magnifiers are the second generation. However, magnification is not the only modification of print that can make it more readable for low vision people. Research (1,2,3) has shown that type font, letter spacing, and color can effect letter recognition in different ways depending on the visual impairment. In addition, with specific visual impairments reading speed can be significantly improved if text is scrolled or moved across the field of view in certain ways.

While magnification alone can make documents readable that are otherwise unreadable with certain visual impairments, this reading is often slow, tedious, and fatiguing. These realizations led us to the development of a document reading system aimed at making reading as fast and easy as possible by people with low vision.

Since visual impairments vary widely, this goal requires the reading system to be adjusted to accommodate the user's vision. For example, optimal adjustment for a person with macular degeneration can be very different than the optimal adjustment for a person with central field tunnel vision.

The following video, which was shown on KRON TV in the San Francisco Bay Area on December 3, 1997, illustrates the reading system, called VIP(TM) (for Versatile Image Processor), which we developed.

DESIGN FEATURES

The VIP Reading System has the following design features:

  • Text attributes of font, color, size, and letter spacing are adjustable over wide ranges to provide an optimal viewing configuration for most visual impairments.
  • Any of the following views can be selected for optimal reading speed given the visual impairment and the document:
  • 1) Marquee View -- The text is reformatted into one long line which scrolls across the screen at a rate controlled by the user. Since there are not ends of lines and beginnings of next lines, no time is lost changing lines, which can be very significant, especially when large magnification is needed.
  • 2) RSVP View (for Rapid Serial Visual Presentation) --The text is presented one word at a time at the same location. The location can be such that the word is left justified, center justified, or right justified. Each word is presented for a equal length of time controlled by the user, or if synthetic speech is turned on, for a length of time equal to how long it takes to say the word at the speaking rate determined by the user.
  • 3) Word Wrap View -- For the chosen magnification and letter spacing, a screen of text is presented with lines as long as possible without splitting words, and as many lines as can fit on the screen. This screen can scroll vertically, or stepped one screen at a time. Speech can be turned on with the word or line highlighted that is being spoken.
  • 4) Image View -- This view shows an image of the document in the upper part of the screen. An image of one line is magnified an adjustable amount and scrolled across the bottom of the screen. The corresponding line is highlighted in the upper part of the screen. Line changes are automatic. Optical character recognition is not used in this view, so the images presented are direct views of the images acquired by the scanner, with image processing to smooth the line strokes and to separate the characters.
  • 5) Locator View -- The purpose of this view is to locate and reposition the starting point for any of the views above. It consists of a full image of the page with a small magnifying window superimposed. This magnifying window can be positioned anywhere on the page and this position determines the starting point for any of the views above.
  • Up to 99 different user configurations can be stored and quickly retrieved for multiple user situations or situations in which different configurations are preferred for different documents.
  • There is a picture viewing function which allows full color pictures to be displayed with adjustable magnification.
  • There are three user levels to accommodate different needs, available learning time, and abilities.
  • 1) ezVIP(TM) -- At this level reading of scanned documents is controlled with the two mouse buttons, one to scan and the other to start and stop the scrolling and speech.
  • 2) VIPinfoSoft(TM) -- This intermediate level adds a library, locator screen, and picture viewing. Control is with the mouse and the number pad on the keyboard.
  • 3) VIPinfoSoft Plus(TM) -- This advanced level adds e-mail, address book, auto dial, memo editor, printing, and cut/copy/paste commands to/from other application programs through the clipboard. Control is with the mouse and full keyboard.

Information from the following sources can be accessed with the system:

  • 1) Printed documents -- a wide range of printed documents can be successfully read: books, newspapers, magazines, etc.
  • 2) e-mail -- messages can be received and read is the same fashion as printed documents. Messages can be written with the built-in large print/speech editor and sent as new, replies, or forwards.
  • 3) CD -- text stored on CDs can be read in the same fashion as printed documents, making scanning unnecessary.
  • 4) Camera -- with the video camera accessory, the system operates as a video magnifier (CCTV) plus frames can be stored, colors changed, and enlarged electronically. This accessory is used to view three dimensional objects, such as prescription bottles, cans, etc., and to provide magnified image feedback when handwriting.
  • 5) Internet -- with the VIPinfoNet(TM) program, web sites can be read in the same fashion as printed documents. In addition links can be downloaded, bookmarks placed, and tables viewed by row and column.
  • The user interface is designed to be easy to use by people with visual impairments and with no previous computer experience. No pointers, pull down menus, or radio buttons are used because these components are difficult for many visually impaired persons. Instead, menu selections are placed on large virtual buttons labeled with large print in the four corners of the screen. These virtual buttons correspond to the four real buttons in the four corners of the number pad (7,9,1,and 3). Adjustment of a menu item (e.g., size, letter spacing, etc.) is done with the 4 and 6 keys.
  • All standard hardware is used in VIP systems, so users can purchase either software alone, or complete systems which can also be used normally as a computer. VIP software programs are application programs running under Windows 95.
  • VIP scanned document reading programs include an Optical Character Recognition (OCR) engine (Textbridge(R) by Xerox) and a synthetic speech engine (Flextalk(R) by AT&T). VIPinfoNet includes the Flextalk synthetic speech engine.
  • The following Help systems are built into VIPinfoSoft, VIPinfoSoft Plus, and VIPinfoNet:
  • 1) Pressing the help key (number 5 on the number pad) displays a large print screen picture of the number pad with the keys active at that point in the program indicated. In this help mode, a spoken and large print explanation what a key does can be obtained by pressing the key. The second consecutive press of the key performs the action.
  • 2) There is on-line help available by pressing Function key one.
  • 3) A full manual can be stored in the built-in Library and viewed in the same way as any scanned document.
  • 4) VIPinfoNet has a mode for learning the keyboard commands. When a key is pressed in this mode, the function that key performs is explained in speech without the action being taken.

CONCLUSION AND FUTURE TRENDS

Even though VIP systems have been available only for a relatively short time, there are already many VIP Reading Systems being used in individual homes and offices, in libraries, in schools, and in centers for people with visual impairments.

Compared to video magnifiers (CCTVs), VIP Reading Systems are enabling faster and easier reading and much greater functionality at a similar cost. By basing VIP Reading Systems on PC technology rather than television technology, future developments and uses of the hardware are unlimited, compared with the dead-end future of video magnifiers.

Therefore, the future trend will be to replace video magnifiers (CCTVs) based on television technology with PC based reading systems which are becoming the third generation of systems to assist low vision readers.

References:

1. A. Arditi, K. Knoblauch, and I. Grunwald, "Reading with fixed and variable pitch", J. Opt. Soc. Am. A, Vol. 7, No. 10, pp. 2011-2015, Oct. 1990.

2. G. E. Legge, G. S. Rubin, D. G. Pelli, and M. M. Schleske, "Psychophysics of Reading-II: Low Vision", Vision Res., Vol. 25, No. 2, pp.253-266, 1985

3. J. S. Mansfield, G. E. Legge, and M. C. Bane, "Psychophysics of Reading-XV: Font Effects in Normal and Low Vision", Investigative Ophthalmology & Vision Science, July 1996, Vol. 37, No. 8, PP 1492-1500.

Go to the top of this page. | Go to the upper category.