Fractal-dithering technique for image display
US7206001B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 22, 2004 |
| Grant date | Apr 17, 2007 |
| Priority date | — |
| Expiry date | Jun 22, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG09G3/2003
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Rapid dithering of an RGB image from a higher order to a lower order number of bits is provided while introducing fewer undesirable artifacts than are visible in conventional dithering technology. A compact, deterministic method enables the elimination of banding, for example as is seen in 24-bit monitors when viewing color images with greater color depth. A fractal dithering engine selects a threshold matrix appropriate for an input stream, and using the threshold matrix, dithers images of the input stream to output images having a lower order number of color bits. In one embodiment, the threshold matrix is obtained by traversing 2-by-2 sub-regions of an N-by-N matrix according to a traversal pattern, and then applying a reverse binary function to the values in the original matrix to yield the threshold matrix. The threshold matrix preferably tessellates the pixel plane, subject to certain constraints.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.