IMAGE PROCESSING APPARATUS, PRINTING APPARATUS, IMAGE PROCESSING METHOD, AND PRINTING METHOD

• US 20160295077A1
• Filed: 03/24/2016
• Published: 10/06/2016
• Est. Priority Date: 04/06/2015
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: KAKUTANI, Toshiaki
• Granted Patent: US 9,832,350 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06K 15/1881 Halftoning halftoning of still images in general H04N1/405, H04N1/52
• CPC Class Codes: G06K 2215/101 involving the use of ink jets
• CPC Class Codes: H04N 1/4057 the pattern being a mixture of differently sized sub-patterns, e.g. spots having only a few different diameters multi-toning H04N1/40087
• CPC Class Codes: H04N 1/52 Circuits or arrangements for halftone screening
• CPC Class Codes: H04N 1/6008 with primary colour signals, e.g. RGB or CMY(K)
• CPC Class Codes: H04N 1/6027 Correction or control of colour gradation or colour contrast H04N1/6058 takes precedence

Abstract

An image processing method includes performing first halftone processing and second halftone processing. The second halftone processing is performed, for a second kind of color in advance among a plurality of colors constituting an original image, in units of blocks each consisting of a plurality of pixels that constitute the original image and the second kind of color is converted into an amount of second kind of ink corresponding to the second kind of color among the plurality of inks. The first halftone processing is performed, for the first kind of color, for each pixel that constitutes the original image or each pixel group having a smaller number of pixels than the block and the first kind of color is converted into an amount of first kind of ink corresponding to the first kind of color among the plurality of inks.

Claims

1. An image processing apparatus which converts an original image into a representation obtained by using a plurality of inks, the image processing apparatus comprising:

a first halftone unit which performs first halftone processing which is determined in advance; and

a second halftone unit which performs second halftone processing which is different from the first halftone processing,

wherein the second halftone unit is configured to perform the second halftone processing, for a second kind of color which is a color other than a first kind of color, which is a single color or a plurality of colors determined in advance among a plurality of colors constituting the original image, in units of blocks each consisting of a plurality of pixels that constitute the original image and convert the second kind of color into an amount of second kind of ink corresponding to the second kind of color among the plurality of inks, and

the first halftone unit is configured to perform the first halftone processing, for the first kind of color, for each pixel that constitutes the original image or each pixel group each having a smaller number of pixels than the block and convert the first kind of color into an amount of first kind of ink corresponding to the first kind of color among the plurality of inks.

2. The image processing apparatus according to claim 1,

wherein the first halftone processing performed by the first halftone unit is processing with image quality higher than the second halftone processing performed by the second halftone unit.

3. The image processing apparatus according to claim 1,

wherein the first kind of color includes at least a black color.

4. The image processing apparatus according to claim 3,

wherein the first kind of color includes only the black color.

5. The image processing apparatus according to claim 1,

wherein the halftone processing is processing which directly determines whether or not dots are to be formed by the first kind of ink corresponding to the first kind of color on the basis of a gradation value of the first kind of color.

6. The image processing apparatus according to claim 1,

wherein the second halftone processing performed by the second halftone unit is processing performed at a higher speed than the first halftone processing performed by the first halftone unit.

7. The image processing apparatus according to claim 6,

wherein the second halftone processing is processing of comparing a threshold value stored in a dither mask with the gradation value of the second kind of color, in units of the blocks.

8. The image processing apparatus according to claim 1,

wherein the second halftone unit is configured to perform the processing for the second kind of color using an average value of the plurality of pixels within the block.

9. The image processing apparatus according to claim 1,

wherein the first halftone unit is configured to determine, for the first kind of color, whether or not the first kind of color is present in any of the pixels within the block and perform the first halftone processing only on the pixel in which the first kind of color is present.

10. The image processing apparatus according to claim 1,

wherein the first halftone processing by the first halftone unit and the second halftone processing by the second halftone unit are performed for all the pixels of the original image and an ink amount of the second kind of ink is replaced with the ink amount of the first kind of ink for the pixel in which the ink amount of an ink corresponding to the first kind of color which is the processing result is not zero.

11. The image processing apparatus according to claim 1,

wherein the first halftone unit performs the first halftone processing by defining a color of all the pixels as the first kind of color in a case where the first kind of color is present in any of the pixels within the block, and

the image processing apparatus further comprises a halftone processing results synthesization unit which synthesizes a result of the first halftone processing and a result of the second halftone processing on the basis of a position of the pixel in which the first kind of color is present to obtain a result of the image processing.

12. The image processing apparatus according to claim 1,

wherein first processing of defining a bundle of rasters each of which is an arrangement of pixels arranged in one direction in the original image as a processing raster, the processing raster including at least one of the blocks handled by the second halftone unit, and second processing of generating intermediate data obtained by combining an ink amount obtained by converting gradation data of the second kind of color in units of blocks into an ink amount of the corresponding second kind of ink, and an ink amount of the first kind of ink that corresponds to the first kind of color of each pixel or each pixel group having a smaller number of pixels than the block for each processing raster are performed, and

the intermediate data is processed by the first and second halftone unit so as to generate dot data that represents the presence or absence of dots to be formed that correspond to the ink amount of the first kind of ink and the second kind of ink.

13. The image processing apparatus according to claim 12,

wherein the intermediate data generated in the second halftone processing is stored in a form encoded with the amount of ink obtained by converting gradation data of the second kind of color in units of blocks into an ink amount of the corresponding second kind of ink and information about the number of dots to be formed in the block and a dot position in the block.

14. The image processing apparatus according to claim 13,

wherein a dither mask which is larger than the block is prepared, and

the encoding is performed by encoding the comparison result of a number of threshold values corresponding to the number of pixels included in the block in threshold values included in the dither mask with the ink amount of the second kind of ink.

15. The image processing apparatus according to claim 14,

wherein the dither mask which is larger than the block is prepared, and

the encoding is performed by combining information obtained by ranking sizes of a number of thresholds corresponding to the number of pixels included in the block in the threshold values included in the dither mask and the number of dots to be formed in the block determined on the basis of the ink amount of the second kind of ink.

16. A printing apparatus which prints an original image using a plurality of inks, the printing apparatus comprising:

a first halftone unit which performs first halftone processing which is determined in advance;

a second halftone unit which performs second halftone processing which is different from the first halftone processing; and

a dot formation unit configured to form a dot on the basis of an ink amount which is a halftone result of the first and second halftone unit,

wherein the second halftone unit is configured to perform the second halftone processing, for a second kind of color which is a color other than a first kind of color which is a single color or a plurality of colors determined in advance among a plurality of colors constituting the original image, in units of blocks each consisting of a plurality of pixels that constitute the original image and convert the second kind of color into an amount of second kind of ink corresponding to the second kind of color among the plurality of inks,

wherein the first halftone unit is configured to perform the first halftone processing for the first kind of color, for each pixel that constitutes the original image or each pixel group having a smaller number of pixels than the block, and convert the first kind of color into an amount of first kind of ink corresponding to the first kind of color among the plurality of inks,

wherein the dot formation unit is configured to form a number of dots corresponding to the ink amount converted by the first halftone unit and second halftone unit for each ink so as to record an image corresponding to the original image.

17. An image processing method for converting an original image into a representation obtained by using a plurality of inks, the image processing method comprising:

performing first halftone processing which is determined in advance; and

performing second halftone processing which is different from the first halftone processing,

wherein the second halftone processing is performed, for a second kind of color which is a color other than a first kind of color which is a single color or a plurality of colors determined in advance among a plurality of colors constituting the original image in units of blocks each consisting of a plurality of pixels that constitute the original image and the second kind of color is converted into an amount of second kind of ink corresponding to the second kind of color among the plurality of inks, and

wherein the first halftone processing is performed, for the first kind of color, for each pixel that constitutes the original image or each pixel group having a smaller number of pixels than the block and the first kind of color is converted into an amount of first kind of ink corresponding to the first kind of color among the plurality of inks.

18. A printing method for printing an original image using a plurality of inks, the printing method comprising:

performing first halftone processing which is determined in advance;

performing second halftone processing which is different from the first halftone processing; and

forming a dot on the basis of an ink amount which is a halftone result in performing the first and second halftone processing,

wherein the second halftone processing is performed, for a second kind of color which is a color other than a first kind of color which is a single color or a plurality of colors determined in advance among a plurality of colors constituting the original image, in units of blocks each consisting of a plurality of pixels that constitute the original image and the second kind of color is converted into an amount of second kind of ink corresponding to the second kind of color among the plurality of inks,

wherein the first halftone processing is performed, for the first kind of color, for each pixel that constitutes the original image or each pixel group having a smaller number of pixels than the block and the first kind of color is converted into an amount of first kind of ink corresponding to the first kind of color among the plurality of inks,

wherein in forming the dot, a number of dots corresponding to the ink amount converted by the first halftone unit and second halftone unit is formed for each ink so as to record an image corresponding to the original image.