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Low-Cost Option: Slow-Scan Video.

Low-Cost Option: Slow-Scan Video

Video-teleconferencing is generally associated with elaborate boardroom installations which provide large-screen viewing with full color and full motion, as well as a host of assessories. Relatively few such facilities are presently in existence, and usage is reportedly lower than might be expected for such a well-publicized form of telecommunications. In fact, some of the user reactions reported are not completely favorable.

After careful analysis of visual communications needs, a number of major corporations and institutions have selected slow-scan television (sometimes called "freeze-frame') as an alternate mode of video-teleconferencing. The two major reasons for this are the relative economy of audio-grade communications circuits and that such facilities are readily available worldwide.

It might reasonably be asked, "Why not use facsimile?' and, indeed, this has been done many times in audiographic teleconferencing. The major advantage of slow-scan television in an interactive meeting is simply its format flexibility. Typically, a conventional closed-circuit TV camera is used in conjunction with a solid-state scan converter in order to generate narrow bandwidth, single-frame, video signals for transmission purposes. Ordinary TV monitors are used for display purposes, and the end result can be that the viewer has the option of looking at a small monitor located on the corner of a desk, a large-screen projection, a simultaneous distribution of imagery to many nearby locations, a tape recording of both the sound and video components of a conference, or a "hard copy' record, if needed.

The use of CCTV components at the transmitting end of the system allows the viewing of any size subject, from the microscopic to the very large. Three-dimensional objects are easily viewed and color reproduction is available if desired. A partial list of subjects appropriate to slow-scan TV transmission includes flat copy such as slides, photographs, x-rays, diagrams, layouts, schematics, maps and stamps, and three-dimensional subjects such as people, machinery, products and traffic.

Slow-scan television may also be used for data transmission, such as observation of status boards, meter readings, radar scans or computer-generated graphics. Due to the relatively low data rate, slow-scan TV may also be readily interconnected to digital computers in order to achieve additional functions such as encryption, image enhancement, or storage and retrieval.

In essence, slow-scan provides virtually all of the advantages of wideband television, except for the ability to see someone move their lips, shift their eyes, and wave their arms. How well then is this form of video-teleconferencing accepted in the marketplace? Compared to full-motion video, the reaction seems to be quite positive when medium- or long-distance communications are required. Industry estimates are that over 300 slow-scan TV teleconferencing systems were sold in the United States during 1982, probably 10 times the number of digital full-motion systems.

Although executive teleconferencing has been widely publicized, usage in a large corporation may cover a variety of applications, such as engineering, construction, information retrieval, field service, security, environmental monitoring, presentations, instruction, advertising, sales, and medical emergencies.

It is also important to note that slowscan communications equipment need not be elaborate, or even used in a fixed location. In many instances, video information exchange has proven itself of value in projects lasting only a few months or even weeks.

Engineering applications rank high in terms of general use of slow-scan television, and frequently, equipment is used by relatively small groups of individuals who are involved in special projects. Originally thought of as a means of saving travel dollars, videoconferencing experience has brought to light the fact that sometimes very large payoffs are achieved by greatly accelerating the solution of problems. The old adage, "Time is money,' has been vividly affirmed on occasions when design, production or construction projects have been expedited by bringing people together via visual communications.

Saves Human Resources

Teleconferencing also conserves human resources, and these may be more valuable, from a strictly cost accounting point of view, than savings in airline fares and hotel rooms. Furthermore, it may make individuals available whose schedules would not allow them to be present in person.

The concept of guest lecturer via slow-scan television was poineered by Dr. David Swift of the University of Hawaii, and has allowed students to hear and "see' eminent authorities from distant locations and to "attend' video tours.

In the last two years, over 30 slow-scan "telepresentations' have been made to audiences both nationally and internationally The ordinary telephone system has provided fast, economical communications with groups in London, Paris, Berlin, Zurich, Vienna and Sydney. In two instances, pictures were transmitted from Europe to the MIT Visible Language Workshop Laboratory, processed by computer, and retransmitted to the originating point as well as to the US.

Multipoint transmission and reception is easily accomplished through use of standard audio bridges. At the 1983 annual meeting of the Association of College and University Telecommunications Administrators, eight locations throughout the US were tied together through the Kellogg bridge in Denver, with formal presentations being made from the University of Wisconsin and New York University, as well as before the main audience at the actual convention location in Boulder, Colorado.

More formal use of slow-scan television for teaching purposes dates back over a decade. Presently, twelve institutions are using this medium for instructional purposes, with the largest being the University of Wisconsin, which has installed equipment at 26 sites.

Telemedicine is a significant and growing use of slow-scan TV. Originally thought of as an economical means of providing emergency service to the small, isolated community, it is now considered to be a valuable instructional and training device, allowing doctors, nurses and paramedics access to experts at major hospitals.

Teleradiology, a branch of telemedicine, is also an important and expanding field. Again, slow-scan television allows rapid diagnosis and consultation, with some radiologists carrying portable equipment when they travel.
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Author:Southworth, G.
Publication:Communications News
Date:Feb 1, 1984
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Next Article:Emotions of Surprise and Concern Fanned by Telephone Rate Changes.

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