Color image processing with undercolor removal suitable for use in digital processing
US5126838A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 19, 1991 |
| Grant date | Jun 30, 1992 |
| Priority date | — |
| Expiry date | Feb 19, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/58
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An image processing apparatus extracts an edge or line portion of an image, judges grayness of the image, and processes the image according to outputs of the means used for the edge- or line-extraction and grayness-determination. The further processing may, for example, comprise undercolor removal and/or black-addition. Edge extraction can be performed by use of a Laplacian. The grayness can be judged by, for example, providing a colorlessness signal formed from two color component signals. Extraction of a line region, instead of Laplacian edge extraction, can be performed, for example, by use of an Hadamard transformation. Also, the invention more generally includes detecting grayness of an image, detecting other characteristics of the image, and judging additional characteristics of the image according to the first two determinations.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.