Method and circuit for composing still image of picture-in-picture
US5021887A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 13, 1989 |
| Grant date | Jun 4, 1991 |
| Priority date | — |
| Expiry date | Dec 13, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N5/45
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A circuit for composing a still sub picture video image for a picture-in-picture (PIP) video display displaying a main picture and a sub picture in an area of the main picture includes a write address generator for storing in a memory the sub picture data of every second line of an input video image field so as to vertically compress the input image field data, along with a read address generator which reads-out the data stored at odd-numbered memory addresses in step with the horizontal sync signal of the first field of the main picture signal to compose a first video field of the sub picture display and which also reads out the data stored at even-numbered memory addresses in step with the horizontal sync signal of the second field of the main picture signal to compose a second video field of the sub picture display, enabling a sub picture consisting of first and second sub picture image fields but composed from the data of only a single input image field to be displayed in step with the corresponding first and second fields of the main picture. The circuit and corresponding method for composing a still video sub picture for PIP video displays compress the input image field data …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.