Method for antialiasing fonts for television display
US6229521A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 10, 1997 |
| Grant date | May 8, 2001 |
| Priority date | — |
| Expiry date | Apr 10, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N5/21
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method for generating a font for display on an interlaced monitor which is relatively free of the distorting effects of interlacing. The method operates by obtaining an original bitmap for a character in the font which is larger than a desired size for the font. This original bitmap is subjected to a weighted filtering to produce a filtered bitmap. The filtered bitmap is reduced to a desired font size by dividing the filtered bitmap into a plurality of tiles. Each tile is subjected to an unweighted filtering to produce an average value, which is rounded to produce a value for a corresponding pixel in a reduced bitmap. Next, the reduced bitmap is quantized to form a bitmap for display by setting all values which exceed an upper quantization limit to the upper quantization limit, and if necessary, setting all values which are below a lower quantization limit to the lower quantization limit. If a color display is used, pixels within the bitmap for display are used to index a color map, which contains a range of blendings of a font color with a background color, to produce a color bitmap for display. Coefficients in the weighted filtering process can be iteratively adjusted to achiev…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.