System to capture, store, and retrieve composite video for transmission over telephone lines
US6380967B1 · kind B1 · utility
Inventor
Key dates
| Filing date | Dec 7, 1996 |
| Grant date | Apr 30, 2002 |
| Priority date | — |
| Expiry date | Dec 7, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N7/141
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A simple, low-cost videophone system for transmitting and receiving still video images over a standard telephone line in response to a user command. A video processor circuit, comprising an A/D converter, a digital memory, a digital timing circuit, and a D/A converter, can grab a video image from a standard video camera and store one-half the number of lines of a video frame in the digital memory. A still video image can be displayed in a standard TV monitor by repeatedly sending the data stored in the digital memory to the D/A converter. The data stored in the digital memory can be transmitted using a standard modem to the digital memory of an equivalent system at a remote location, and the same still video image can be displayed at the remote location within a short time. Data compression is accomplished during transmission by decreasing the number of significant bits of the data being transmitted and using standard protocols adopted by the modem. Voice communication on the telephone line is temporarily suspended while data is transmitted, and automatically resumed when transmission is complete.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.