the inside of the viewing area. This border exists to keep new objects from being too close to the edge of the screen, and closer to the more visible center of the view. In JumpScroll, when new objects are received, their bounding box location is compared to the location of the Interior Tolerance Border. If any of the four sides of the object’s bounding box are outside of the border, the view is automatically scrolled so that the object is just inside the left and/or upper Interior Tolerance Borders. The view is only scrolled in the direction this border is crossed, so the Interior Tolerance Border is not really a rectangle, but a set of four boundaries that extend across the entire view.

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v-VIS: New Methods of Passive Information Grouping in a Classroom Tool for Low Vision StudentsBen Betz, DePauw University

Faculty Advisor: Dr. Dave BerqueIntroduction

The v-VIS System

Magnification is especially important for students with reduced visual acuity. v-VIS can magnify the image in its viewing area so that it appears up to 1000% of its original size.

As important as magnification is to the use of v-VIS, many persons with reduced vision still cannot see even magnified images unless they are in specific colors or contrast schemes. For this reason, the viewing area of v-VIS can be set to use any combination of colors. Both the background and a set of four drawing colors can be individually chosen based on the users specific needs. For example, many persons with limited vision use a yellow ink on blue background scheme.

Screen Mapping – A Problem

Two Methods for Automatically ScrollingThe basic principle behind AutoScroll is rather simple: If a newly received object is not completely visible on the screen, scroll the view so that it is. At the same time, AutoScroll attempts to retain the context of the newest object. This is especially important to low vision students who have no other means of knowing where the newest information is being written. By keeping nearby and often related objects on the screen, AutoScroll provides contextual information to the v-VIS user. It does so by analyzing only the newest object and not any previously drawn objects. AutoScroll is therefore a passive information grouping method, since it does not actively examine the information it is grouping. Two different AutoScroll algorithms have been developed: JumpScroll and SmoothScroll.

Method 1: JumpScroll

JumpScroll was designed in this manner to move new letters (drawn objects) to the left of the screen, providing space for the letters the professor would soon write. Unfortunately, JumpScroll often caused words to be split in half as a letter in the middle of the word would cross the Interior Tolerance Border, causing the first portion of the word to “jump” off of the screen. This obviously was not grouping information very well.

Method 2: SmoothScroll

Comparison of Autoscroll Methods

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The upper graph shows that AutoScroll is very effective at passively grouping individual letters into words. SmoothScroll operated in a much more effective manner than JumpScroll, grouping the highest percentage of the data in the test. Performance decreases at higher magnification levels, since the effective view space is reduced and a large number of letters cannot be physically displayed on the screen. The grouping of multiple words on screen at the same time to provide context is rather effective at lower magnification. For example, at 100% magnification, 4 or more words were completely on the screen a majority (67.1%) of the time. Again, performance decreased at higher magnification due to the limited screen size.

Conclusions and Future WorkBased upon the performance test, it is evident that SmoothScroll performs better than JumpScroll. Preliminary evaluation by two low-vision persons suggest that while the SmoothScroll algorithm works well, its performance can still be improved. The current Tolerance Frame, for example, would most likely result in better performance if it were scaled in size based on the magnification level. For future work, we plan to continue development of AutoScroll algorithms. The v-VIS interface can also be improved, including the addition of auditory feedback.

Acknowledgements

This research was supported in part by DePauw University’s Science Research Fellows program and an REU grant from the NSF (grant #EIA-9911626).

Both methods of AutoScroll are based on the fact that each object drawn on the v-VIS screen has a bounding box, a rectangular set of boundaries that define the object’s position. This box allows v-VIS to easily determine if an object is visible and if it is, the amount of the object that is visible on screen.

References

Berque, Dave, et. Al. The Design of an Interface for Student Note Annotation in a Networked Electronic Classroom. Journal of Network and Computer Applications. 23, (2000). 77-91.

Kline, Richard L. and Ephriam P. Glinert. Improving GUI Accessibility for People with Low Vision. Conference proceedings on Human factors in computing systems, ACM Press, Pages 114 - 121, 1995.

Lynch, Patrick J. and Sarah Horton. Web Style Guide: Basic Design Principles for Creating Web Sites. New have,

CT: Yale University Press. 86.

Jacko, Julie A. and Andrew Sears. Designing Interfaces For an Overlooked User Group: Considering the Visual Profiles of Partially Sighted Users. Proceedings of the third

international ACM conference on Assistive Technologies, 1998, ACM, Marina del Rey, CA. 75-77.

Perkins, Robert. Provision of Services For Students With Visual Impairments: A Case Study. Information Technology and Disabilities. 7 (2), <http://www.rit.edu/~easi/itd/itdv07n2/contents. htm>.

Vener, Avram R. and Ephriam P. Glinert. MAGNEX: A Text Editor for the Visually Impaired. Proceedings of the

1988 ACM sixteenth annual conference on Computer Science, 1988, Pages 402 - 407.

SmoothScroll extends the JumpScroll algorithm to determine what portion of an object is visible. Whereas JumpScroll rescrolls to the upper and left sides of the screen whenever any side of an object’s bounding box crosses the Interior Tolerance Border, SmoothScroll “jumps” only when the object is completely outside of the view. The Exterior Tolerance Border is used to determine if the object’s bounding box is completely outside of the view. If the object is partially visible, or its bounding box is across the Interior Tolerance Border, but it is not entirely outside the Exterior Tolerance Border, the scroll places the object just inside the Interior Tolerance Border that was crossed.

JumpScroll and SmoothScroll both use a Tolerance Frame to determine if a newly received object is completely on screen. This frame is a small area around each edge of the viewing area outside of which an object is considered to be out of view. The Interior Tolerance Border marks the beginning of the frame on nespacer>

The performance of the two AutoScroll methods was evaluated objectively by counting handwritten word completion. Ten pages of data recorded from a class taught on an electronic whiteboard were fed to the v-VIS system stroke-by-stroke, once for each AutoScroll method. Two statistics were collected at multiple zoom factors: • How many times the most recent word was completely on the screen when it was fully received•How many complete words were concurrently on the screen at that time

Whiteboard Screen

v-VIS Screen

The v-VIS viewer operates on a Handheld PC running Windows CE. The professor writes class notes on either a touch-sensitive rear-projection whiteboard or a pen-based video tablet combined with a video projector. Either of these input devices is attached to a computer that transmits all of the drawn information across a high-speed network to the handheld, which re-displays the image. Fully sighted students can see the image on the large display in the front of the room, but the low vision student(s) can view the information at close range on the handheld screen. The transmitted information can also be annotated by the student using a stylus on the handheld’s touch sensitive screen.

The design of v-VIS centers on creating a user interface that persons with limited vision can use in a classroom. Therefore the v-VIS application contains integrated magnification and color customization options. These features are commonly found in commercial software designed to make a standard computer screen usable by persons with low vision. Since there are a variety of visual disabilities, each requiring specific display settings, v-VIS has been designed to accommodate and easily adapt to the needs of each individual user.

Students with limited vision often have to employ note-takers or reading services in order to obtain access to class material. Though admirable, these services are often slow and inefficient. With the recent advent of mobile computing devices, it is now possible to develop low-cost, portable software solutions for a variety of tasks. For example, there are many mobile applications designed to help business people and students in their work environments. There is a significant lack, however, of mobile systems designed to aid persons with disabilities. The development of mobile assistive technology – as such systems are called – is the focus of this project, which explores the design of mobile software tools intended to alleviate the problems low vision students have in reading the information written on a classroom blackboard. One possible tool is a system we have developed called v-VIS (vviewer for VVisually IImpaired SStudents). The prototype of v-VIS functions as an automatic note-taker and visually enhanced viewer for the information written on an electronic whiteboard.

The solution we developed is called AutoScroll. As the viewer receives new objects drawn by the professor, it repositions its scrollable view window to place the newest object on the screen. Initial efforts have also been made to ensure that other recently drawn objects are retained on the screen.

Early on in the development of v-VIS a significant problem arose: How could the large display at the front of the room be mapped to the smaller handheld screen? Since the aim of v-VIS is to make the professor’s information more visible, shrinking the large display onto the smaller handheld screen is not an acceptable solution. In fact, reduced vision students will most likely have their view magnified, further reducing the effective information space of the v-VIS screen. As a result, v-VIS acts as a sort of “window” into the large display. The drawing surface is completely scrollable so that it contains the same amount of space as the large forward display, but only a portion of it is visible at any given time. This then raises another problem; fully sighted students can easily see where the professor is writing in the front of the class, but a student with reduced vision may have trouble with this task. The ensuing question becomes “How can v-VIS provide an indication as to where the professor is writing?”