Halftone image recording method and apparatus therefor

• US 4,727,430 A
• Filed: 04/23/1986
• Issued: 02/23/1988
• Est. Priority Date: 06/12/1985
• Status: Expired due to Term

• Current Assignee: Dainippon Screen Manufacturing Company Limited
• Original Assignee: SCREEN Holdings Co., Ltd.
• Inventors: Miwa, Mamoru
• Primary Examiner(s): COLES, EDWARD L
• Application Number:
  US06/854,872
• Time in Patent Office: 671 Days
• Field of Search: 358/283, 358/280, 358/298, 358/80
• US Class Current: 358/3.11
• CPC Class Codes: H04N 1/40012 Conversion of colour to monochrome
• CPC Class Codes: H04N 1/405 Halftoning, i.e. converting the picture signal of a continuous-tone original into a corresponding signal showing only two levels
• CPC Class Codes: H04N 1/52 Circuits or arrangements for halftone screening

Abstract

A halftone image is reproduced and recorded by photoelectrically scanning an original in the following manner. One of the density range, hue range and coordinate range of the original or an image, which has been obtained by modifying the original as desired, is divided into a suitable number of regions having a prescribed width. One of plural kinds of halftone signals of different halftone shapes is then selected for each of the thus-divided regions in accordance with a region signal corresponding to the same divided region, whereby a halftone image containing plural kinds of dot shapes is recorded. An apparatus for practicing the above method is also described.

Claims

1. A printing plate apparatus for reproducing and recording a halftone image by photoelectrically scanning an original in a single scanning pass, said original having density range, hue range and position range, said apparatus comprising:

means for dividing one of the density range, hue range and position range of the original into regions having predetermined widths;

means for outputting region signals corresponding to the regions;

means for selecting one of differing halftone signals of different halftone shapes for each of the regions in accordance with said region signals;

means for generating the differing halftone signals of the different halftone shapes; and

signal comparator means for comparing an image signal corresponding to the region of the region signal and the halftone signal selected in accordance with the region signal and outputting an image signal for recording a reproduced image.

2. An apparatus as claimed in claim 1, wherein said apparatus is additionally equipped with a memory unit adapted to store pixel signals in combination with their corresponding region signals.

3. A printing plate method for reproducing and recording a halftone image, comprising:

photoelectrically scanning, in a single pass, an original, having density range, hue range and position range;

having density range, hue range and position range;

dividing the original into pixels;

sectioning any of density range, hue range relating to each of said pixels, and position range on which said pixels locate, into regions having predetermined widths;

outputting region signals corresponding to said regions;

selecting any of a plurality of differing halftone signals of different halftone shapes based on said region signals;

recording a halftone image having said different halftone shapes.

4. The method of claim 3, further comprising comparing an image signal corresponding to said region of said region signal and said halftone signal and outputting an image signal for recording said halftone image.

5. A method as claimed in claim 3, wherein region signals are extracted for each of said pixels obtained by the photoelectric scanning of the original or each of said pixels adapted to record the reproduced image, and picture element signals corresponding to the former or latter picture elements are employed in combination with their corresponding region signals upon suing a memory unit for magnification change of simultaneous recording of said halftone image.