Image processing with noise enhancing operators for moire reduction and/or random dot generation
US5225915A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 9, 1989 |
| Grant date | Jul 6, 1993 |
| Priority date | — |
| Expiry date | Jun 9, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/409
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In an image processing device for processing image data representing an image, and including an image filtering arrangement, a filter function is applied to the image data that greatly amplifies or enhanced high frequency imge data, including noise inherent in the image. Such noise, which may be the granularity of the image, when enhanced, serves to mask the beating pattern of moire. One function which accomplishes adequate high frequency and noise filtering is a modified Laplacian function with a maximum modulation at a frequency of the noise or granularity of the image. Similarly, the special effect of a random screen image or mezzo tint is obtained when a continuous tone image is processed with the modified Laplacian filtering function, and subsequently thresholded in a thresholding arrangement.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.