Method of forming oblique dot pattern

• US 4,805,033 A
• Filed: 04/04/1988
• Issued: 02/14/1989
• Est. Priority Date: 02/18/1987
• Status: Expired due to Fees

• Current Assignee: Olympus Optical Corporation Limited (Olympus Corporation)
• Original Assignee: Olympus Optical Corporation Limited (Olympus Corporation)
• Inventors: Nishikawa, Masaji
• Primary Examiner(s): Goldberg, E. A.
• Assistant Examiner(s): Reinhart, Mark
• Application Number:
  US07/177,266
• Time in Patent Office: 316 Days
• Field of Search: 358/298, 358/300, 358/302, 358/283, 358/284, 358/285, 358/293, 358/294, 358/296, 346/108, 346/107 R, 346/160
• US Class Current: 358/3.1
• CPC Class Codes: H04N 1/4058 with details for producing a halftone screen at an oblique angle H04N1/4056 takes precedence

Abstract

A method of forming an oblique dot pattern in an element-density tone production method which uses two types of recording dots comprising a dark value and a light value and a specific matrix structure, whereby pseudo-gradation recording is performed by assigning recording dot positions in a matrix by means of a matrix pattern in accordance with gradation steps of a recording signal, the oblique dot pattern forming method being characterized in that: a plurality of sets of matrix patterns are provided for the purpose of ensuring that a plurality of different matrix patterns can be selected and assigned to each gradation step; the plurality of sets of matrix patterns being selected and arranged cyclically in matrix pattern areas which are longitudinally and laterally arranged over a recorded image; and the matrix patterns being so constituted that recorded aggregated dots are arranged in a predetermined oblique angle with respect to the longitudinal and lateral directions of the recorded image.

As a result, an oblique arrangement of the aggregation of the recording dots can be easily obtained without involving any complicated conversion calculations or edition process which causes increase in the capacity of the pattern memory.

Claims

1. A method of forming an oblique dot pattern in an element-density tone production method which uses two types of recording dots comprising a dark value and a light value and a specific matrix structure, whereby pseudo-gradation recording is performed by assigning recording dot positions in a matrix by means of a matrix pattern in accordance with gradation steps of a recording signal, said oblique dot pattern forming method being characterized in that:

a plurality of sets of matrix patterns are provided for the purpose of ensuring that a plurality of different matrix patterns can be selected and assigned to each gradation step;

said plurality of sets of matrix patterns being selected and arranged cyclically in matrix pattern areas which are longitudinally and laterally arranged over a recorded image; and

said matrix patterns being so constituted that recorded aggregated dots are arranged in a predetermined oblique angle with respect to said longitudinal and lateral directions of said recorded image.

2. A method of forming an oblique dot pattern according to claim 1, wherein said plurality of sets of matrix patterns are formed by a density pattern method.

3. A method of forming an oblique dot pattern according to claim 1, wherein said plurality of sets of matrix patterns are formed by a dither method.

4. A method of forming an oblique dot pattern according to claim 1, wherein said plurality of sets of matrix patterns are formed by being cut from a plane in which the same gradation step pattern is repeated, in such a manner that cutting positions are offset along an oblique line at 45°

.

5. A method of forming an oblique dot pattern according to claim 1, wherein said plurality of sets of matrix patterns are provided for the purpose of making uniform the number of said recorded dots which are recorded in a dot aggregation.

6. A method of forming an oblique dot pattern according to claim 1, wherein said plurality of sets of matrix patterns are provided for the purpose of making uniform the number and shape of said recorded dots in said aggregation of dots.