System for detecting a video signal image intensity gradient
US5500689A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 26, 1994 |
| Grant date | Mar 19, 1996 |
| Priority date | — |
| Expiry date | Oct 26, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N5/145
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In a video signal processor including a motion compensated predictive coding data compression system, three adjacent image frames (1, 2, 3) are analyzed to detect a luminance gradient such as is typically associated with image fading. The frames are similarly divided into several segments (A . . . L). The sum of the absolute pixel value differences between corresponding segments from adjacent frames is obtained for each of two pairs adjacent frame segments (DIFF.sub.1-2 ; DIFF.sub.2-3). The ratio of the two frame differences (S) is obtained for each segment. Fading is indicated if the ratio remains substantially constant for all or a predetermined number of regions. If fading is detected, any motion vectors generated by the motion coder are assigned a zero value and are not coded.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.