Tinted edge enhancement using harmonic halftones for the boundary pixels
US7688473B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 26, 2004 |
| Grant date | Mar 30, 2010 |
| Priority date | — |
| Expiry date | Jan 9, 2028 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/4058
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Disclosed herein is an image processing method for producing enhanced halftone edges, particularly suited to those edges which only lie upon the background as apposed to those edges which abut other halftone screens. It utilizes a step of defining border pixels and a step of halftoning those border pixels in a different manner than the halftoning applied to the interior region of the tint or image segment. The preferred halftone for the border pixels will be related to the interior halftone by some number of common spatial frequency harmonics. Examples of common-harmonic screening for an edge include, but are not limited to: (a) same screen with different tone reproduction characteristics (boosted edge values); (b) same screen angles and frequencies with a different spot function, possibly phase shifted; (c) a dot screen whose frequency vectors can be generated by the frequency vectors of the interior screen; (d) a line screen whose frequency vectors can be generated by the frequency vectors of the interior screen. This generation process is directed to ensuring that the two screens will be “harmonically matched” where at least one of the fundamental frequency vectors and harmonics…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.