Image sharpening filter providing variable sharpening dependent on pixel intensity
US5854859A · kind A · utility
19Cited by
4References
6Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Dec 27, 1996 |
| Grant date | Dec 29, 1998 |
| Priority date | — |
| Expiry date | Dec 27, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/409
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An automatic level-sensitive Laplacian filter for image processing. Laplacian filter coefficients and normalization divisors are made a function of intensity on a pixel by pixel basis. Pixels indicating a high intensity may be greatly changed by neighboring pixels. Pixels indicating a low intensity receive relatively little or no filtering. In a specific example embodiment, the intensity range is divided into bands, with a different filter for each band. The resulting images are visually sharpened (edge enhanced) with very little impact in darker areas of the image.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.