Half-tone image processing system
US5208684A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 24, 1991 |
| Grant date | May 4, 1993 |
| Priority date | — |
| Expiry date | Apr 24, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2924/181
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A half-tone image processing system provides a density data storage unit for storing density data of each pixel of an original image. A Laplacian calculation unit, operatively connected to the density data storage unit, reads out density data from the density data storage unit. A Laplacian calculation is performed on an object pixel and on peripheral pixels around the object pixel to obtain corrected data. The Laplacian calculation is performed in such a manner that a difference in density between the object pixel and each of the peripheral pixels is calculated and all the differences are summed. A binary-coding unit operatively connected to the Laplacian calculation unit, compares the corrected data with a fixed threshold value to obtain binary-coded data indicating either black or white color in accordance with the threshold value. An error calculation unit, operatively connected to the Laplacian calculation unit and the binary-coding unit, determines a difference between the corrected data and the binary-coded data to obtain a binary-coded error therefrom. An error distribution unit, operatively connected to the error calculation unit, receives the binary-coded error and an erro…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.