Method for adaptively masking off a video window in an overscanned image
US4774569A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 24, 1987 |
| Grant date | Sep 27, 1988 |
| Priority date | — |
| Expiry date | Jul 24, 2007 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/38
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method for extracting (masking off) a desired video window, such as that which forms a scanned image of a document or a portion thereof, from a overscanned image stored in a frame buffer is disclosed herein. Specifically, this method involves first determining horizontal pixel locations for left and right edges of the document for each of a plurality of scan lines located within said scanned image. Then, histograms of the left and right edge locations are fabricated. Once this has occurred, the positions of top and bottom edges of an escribing rectangle is found. The escribing rectangle is a rectangular area, located within the frame buffer, which includes the entire document. Now, with the top and bottom edge locations known, the inventive method locates the right and left edge locations of the escribing rectangle by suitably analyzing the histogram results. Next, memory address corresponding to the first pixel location in the escribing rectangle and the vertical and horizontal size of the rectangle are determined, using all the edge locations of the escribing rectangle, and then applied as input to addressing circuitry located within the frame buffer. Once this occurs, then all…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.