Method and apparatus for detecting changes in raster data
US4958378A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 26, 1989 |
| Grant date | Sep 18, 1990 |
| Priority date | — |
| Expiry date | Apr 26, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG09G2320/103
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method and apparatus which provides for the real time comparison of raster data. The raster data is stored in memory such that raster data corresponding to a specific X-Y coordinate location is consistently written to the same memory location. During the process of storing the data in memory, the data currently stored in the memory is read and compared to the data to be written into the same location in memory. If the data is not the same, the discrepancy and location of the discrepancy is noted in a separate area of memory to be used for subsequent analysis and the data to be written to that location is immediately written into the memory. The method and apparatus of the present invention is particularly applicable to the video graphics environment wherein the current bit of raster image contained in the frame buffer is compared to the updated raster image and the data changes are noted on a pixel by pixel basis. Utilizing the information gathered on the changed pixels, the video display need only update the changed data, thereby minimizing the amount of data to be transferred and increasing the speed of the system. In a preferred embodiment, the method and apparatus of the pres…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.