Picture description instructions, PDI, for the Telidon videotex system / by H.G. Bown, C.D. O'Brien, W. Sawchuk and J.R. Storey.: Co24-3/8-699-1979E-PDF
"The Telidon Videotex system is a method by which information can be accessed from central data bases by the general public. By the use of a domestic home television receiver augmented by a micro-computer controlled interface device a user can access pages of graphical and textual information over a public common carrier communications facility such as the telephone network, a cable television line or the data may be even encoded into unused space in a broadcast television signal. In order to transmit information to a Telidon terminal, at minimum bandwidth, and in a manner independent of the type of communications channel, a coding scheme was devised which encodes a picture into the geometric drawing elements which compose it. These "Picture Description Instructions" are an alpha-geometric coding model and are based on the primitives of POINT, LINE, ARC, RECTANGLE, POLYGON, point by point BIT encoded images and TEXT encoded as ASCII characters. This document provides a detailed specification of this code as well as a description of the principles which make it independent of communications channel and display hardware"--Abstract, page 1.
Permanent link to this Catalogue record:
publications.gc.ca/pub?id=9.891736&sl=0
| Department/Agency | Communications Research Centre (Canada), issuing body. |
|---|---|
| Title | Picture description instructions, PDI, for the Telidon videotex system / by H.G. Bown, C.D. O'Brien, W. Sawchuk and J.R. Storey. |
| Series title | CRC technical note ; no. 699-E |
| Publication type | Series - View Master Record |
| Language | [English] |
| Other language editions | [French] |
| Format | Electronic |
| Electronic document | |
| Note(s) | Issued also in French under title: Instructions de description de l'image, IDI, pour le système vidéotex Télidon. "Technology and Systems Branch." "November 1979." Digitized edition from print [produced by Innovation, Science and Economic Development Canada]. Some pages rotated in this copy. Issued also in print format. |
| Publishing information | Ottawa : Communications Research Centre, 1979. |
| Author / Contributor | Bown, H. G., author. |
| Description | 1 online resource (iii, 71 pages) : illustrations. |
| Catalogue number |
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| Subject terms | Telidon (Data transmission system) Videotex systems -- Canada. Image transmission. |