Generating halftones

Patent metadata

Field	Value
Publication number	US-2018220039-A1
Application number	US-201715422268-A
Country	US
Kind code	A1
Filing date	Feb 1, 2017
Priority date	Feb 1, 2017
Publication date	Aug 2, 2018
Grant date	—

Abstract

A halftone comprises a first halftone screen and a second halftone screen. The first halftone screen comprises a first plurality of amplitude modulated dots arranged according to a first plurality of rows, the first plurality of rows being orientated according to a first direction and comprising a first dot spacing. The second halftone screen comprises a second plurality of amplitude modulated dots arranged according to a second plurality of rows, the second plurality of row being orientated in a second direction and comprising a second dot spacing. The first direction and the second direction define an angle of 45 degrees or less and a ratio of the second dot spacing to the first dot spacing is less than one.

First claim

1 . A method comprising:
generating halftone data representing:
a first halftone screen comprising a first plurality of amplitude modulated dots of a first colorant, wherein the first plurality of amplitude modulated dots are shifted from a first direction comprising a first dot spacing to a shifted direction comprising a shifted dot spacing according to a vector that is parallel to a vector of separation of a second plurality of amplitude modulated dots; and
a second halftone screen comprising the second plurality of amplitude modulated dots of a second colorant arranged according to a second plurality of rows, the second plurality of rows being orientated in a second direction and comprising a second dot spacing;
wherein the first direction and the second direction define an angle of 45 degrees or less and a ratio of the second dot spacing to the first dot spacing is less than one; and controlling a printer to print an image on a print medium based on the halftone data.

2 . The method of claim 1 , wherein the first direction and the second direction define an angle of 45 degrees.

3 . The method of claim 1 , wherein the ratio of the second dot spacing to the first dot spacing is ½√{square root over (2)}.

4 . The method of claim 1 , wherein the first dot spacing defines a resolution of 160 lines per inch and the second dot spacing defines a resolution of 225 lines per inch.

5 . The method of claim 1 , wherein the first halftone screen and the second halftone screen are associated with a pixel array and the first direction is associated with an offset between adjacent dots the first plurality of rows defined in terms of pixels in the pixel array.

6 . (canceled)

7 . The method of claim 1 , wherein the first colorant is a non-black colorant and the second colorant is a black colorant.

8 . The method of claim 1 , wherein the first dot spacing corresponds to a minimum distance between adjacent dots in the first plurality of amplitude modulated dots in the first direction, and the second dot spacing corresponds to a minimum distance between adjacent dots in the first plurality of amplitude modulated dots in the second direction.

9 . The method of claim 1 , wherein the halftone data represents a third halftone screen comprising a third plurality of amplitude modulated dots arranged according to a third plurality of rows, wherein the third plurality of parallel rows orientated in the first direction.

10 . The method of claim 1 , wherein the first plurality of amplitude modulated dots are arranged according to a first square lattice and the second plurality of amplitude modulated dots are arranged according to a second square lattice.

11 . (canceled)

12 . A non-transitory computer-readable storage medium comprising computer-executable instructions which, when executed by a processor, cause a computing device to:
generate data representing a first halftone separation comprising a first plurality of amplitude modulated dots of a first colorant, wherein the first plurality of amplitude modulated dots are shifted from a first plurality of parallel rows and a first dot resolution to a shifted plurality of parallel rows comprising a shifted dot spacing according to a vector that is parallel to a vector of separation of a second plurality of amplitude modulated dots; generate data representing a second halftone separation comprising the second plurality of amplitude modulated dots of a second colorant arranged according to a second plurality of parallel rows and a second dot resolution; wherein the second plurality of parallel rows are orientated at an angle relative to the first plurality of parallel rows of 45 degrees, and the second dot resolution is a harmonic of the first dot resolution; and deposit the first colorant and the second colorant onto a print medium to print the first halftone screen and the second halftone screen.

13 . The non-transitory computer-readable storage medium of claim 12 , wherein a ratio of the first dot resolution to the dot second resolution is ½√{square root over (2)}.

14 . The non-transitory computer-readable storage medium of claim 12 , wherein the computer-executable instructions, when executed by the processor, cause the computing device to:
generate data representing a third halftone separation comprising a third plurality of amplitude modulated dots arranged according to a third plurality of parallel rows and a third resolution, wherein the third plurality of parallel rows are parallel to the first plurality of parallel rows and the third resolution is the same as the first resolution.

15 . An apparatus comprising:
a colorant deposition system to deposit a plurality of colorants on a medium; a processor; and a memory storing computer-executable instructions which, when executed by the processor, cause the processor to: control the colorant deposition system to deposit a first colorant in the plurality of colorants onto the medium to form first plurality of amplitude modulated dots and to deposit a second colorant in the plurality of colorants onto the medium to form a second plurality of amplitude modulated dots; wherein: the first plurality of amplitude modulated dots are arranged according to a first plurality of parallel rows and the second plurality of amplitude dots are arranged according to a second plurality of rows, the second plurality of rows are orientated at an angle of 45 degrees relative to the first plurality of rows; and
the first plurality of amplitude modulated dots are associated with a first dot spacing and the second plurality of amplitude dots are associated with a second dot spacing, and a ratio of the second dot spacing to the first dot spacing is: ½√{square root over (2)}.

Assignees

• Hewlett Packard Indigo Bv

Inventors

• Frank Tal
• Kella Dror
• Tagansky Boaz
• Haik Oren
• Ben-Shoshan Yotam
• Limonov Marina
• Dagan Ram

Classifications

• H04N1/6058

  Reduction of colour to a range of reproducible colours, e.g. to ink- reproducible colour gamut · CPC title

• H04N1/6008

  with primary colour signals, e.g. RGB or CMY(K) · CPC title

• H04N1/4057 Primary

  the pattern being a mixture of differently sized sub-patterns, e.g. spots having only a few different diameters (multi-toning H04N1/40087) · CPC title

• H04N1/52 Primary

  Circuits or arrangements for halftone screening · CPC title