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1. (US5581372) Method for generating and storing digitized density thresholds for rastering a half tone original image

Office : United States of America
Application Number: 08066035 Application Date: 16.05.1994
Publication Number: 5581372 Publication Date: 03.12.1996
Grant Number: 5581372 Grant Date: 03.12.1996
Publication Kind : A
Prior PCT appl.: Application Number:DE91000916 ; Publication Number: Click to see the data
IPC:
H04N 1/40
H04N 1/405
H ELECTRICITY
04
ELECTRIC COMMUNICATION TECHNIQUE
N
PICTORIAL COMMUNICATION, e.g. TELEVISION
1
Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
40
Picture signal circuits
H ELECTRICITY
04
ELECTRIC COMMUNICATION TECHNIQUE
N
PICTORIAL COMMUNICATION, e.g. TELEVISION
1
Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
40
Picture signal circuits
405
Halftoning, i.e. converting the picture signal of a continuous-tone original into a corresponding signal showing only two levels
Applicants: Linotype-Hell AG
Inventors: Kerz Ludo
Agents: Hill, Steadman & Simpson
Priority Data: 4038056 29.11.1990 DE
Title: (EN) Method for generating and storing digitized density thresholds for rastering a half tone original image
Abstract: front page image
(EN)

The object of the invention is a progress for generating and storing digitized density thresholds for defining the grid of a halftone image. The density thresholds of a section of a grid are stored in a data store as stored words depending on a multiple spot function. In the section, several spots with a number of stored words form a multiple spot and are periodically arranged beside and above one another. A sorted sequence is found for the stored words of the section in accordance with the spot function. Density thresholds are allocated to the stored words depending on the position in the sorted sequence. The actual number of stored words is found individually for each spot in the section. The sorted sequence is generated according to the current spot function. Before position-dependent thresholds are allocated the stored words, a center of concentration and final point correction is performed for the spot concerned.


Also published as:
WO/1992/010056