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

• US 20160173724A1
• Filed: 12/15/2015
• Published: 06/16/2016
• Est. Priority Date: 12/16/2014
• Status: Abandoned Application

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: KUWABARA, Masashi, KAKUTANI, Toshiaki, YAMAZAKI, Satoshi
• Application Number:
  US14/969,476
• Publication Number:
  US 20160173724A1
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04N 1/4051 producing a dispersed dots halftone pattern, the dots having substantially the same size different sizes H04N1/4057

Abstract

Provided is a printing apparatus which prints by performing a halftoning process, by setting a block which is formed of a plurality of pixels as a unit, the apparatus including a first determination unit which determines whether or not a gradation value of each of the plurality of pixels satisfies a predetermined condition; a second determination unit which applies different conditions based on a determination result of the first determination unit, and determines whether or not to form a dot in at least one of the plurality of pixels; an error calculation unit which performs a calculation of a gradation error which occurs due to a determination result of the second determination unit, and a distribution of the calculated error to an unprocessed pixel by setting the block as a unit; and a dot forming unit which performs forming of dots using the determination result of the second determination unit.

Claims

1. A printing apparatus which prints an image by performing a half toning process, by setting a block which is formed of a plurality of pixels as a unit, the apparatus comprising:

a first determination unit which determines whether or not a gradation value of each of the plurality of pixels satisfies a predetermined condition;

a second determination unit which applies different conditions based on a determination result of the first determination unit, and determines whether or not to form a dot in at least one of the plurality of pixels;

an error calculation unit which performs a calculation of a gradation error which occurs due to a determination result of the second determination unit, and a distribution of the calculated error to an unprocessed pixel by setting the block as a unit; and

a dot forming unit which performs forming of dots using the determination result of the second determination unit.

2. The printing apparatus according to claim 1,

wherein, in a determination of whether or not the gradation value in the first determination unit satisfies a predetermined condition, when a value corresponding to a gradation value of each pixel in the block is larger than a first threshold value which is a threshold value of a position corresponding to a pixel position among threshold values which are provided as a dither mask, it is determined that the predetermined condition is satisfied.

3. The printing apparatus according to claim 1,

wherein, in the first determination unit, when a gradation value of at least one pixel in the block satisfies the predetermined condition, a dot corresponding to the pixel is formed without making the determination using the second determination unit.

4. The printing apparatus according to claim 3,

wherein, in the first determination unit, when it is determined that a gradation value of any pixel in the block does not satisfy the predetermined condition, the second determination unit determines whether or not to form a dot by comparing image data, which corresponds to a gradation value of a pixel in the block and which is correction image data that has received a distribution of the calculated error with a second threshold value which is a threshold value prepared for error diffusion.

5. The printing apparatus according to claim 1,

wherein a proportion in which it is determined that a predetermined condition is satisfied, in the first determination unit, is a proportion which is lower than a proportion in which a dot is finally formed in a gradation value of the pixel.

6. The printing apparatus according to claim 1,

wherein the second determination unit sets a proportion in which forming of a dot in a pixel in the block is determined to be less than a half of the number of pixels which belong to the block.

7. The printing apparatus according to claim 1,

wherein, when a gradation value of each of the pixels satisfies the predetermined condition, the second determination unit makes the determination by applying a condition in which it is easy to form a dot corresponding to the pixel, compared to a case in which the predetermined condition is not satisfied, and when a gradation value of each of the pixels does not satisfy the predetermined condition, the second determination unit makes the determination by applying a condition in which it is difficult to form a dot corresponding to the pixel compared to the case in which the predetermined condition is satisfied.

8. The printing apparatus according to claim 7,

wherein, when determining forming of a dot compared to a second threshold value which is a threshold value prepared for error diffusion, the second determination unit determines forming of the dot in any one of a pixel at a predetermined position in the block, a pixel which is randomly determined in the block, and a pixel at a position corresponding to a threshold value with a smallest value among threshold values which are provided in a dither mask, and correspond to pixel positions in the block.

9. The printing apparatus according to claim 2,

wherein, in the half toning process, multivalue processing of ternary processing or more is performed based on a determination result of the first determination unit.

10. The printing apparatus according to claim 9,

wherein the first determination unit determines multivalue processing of ternary processing or more by continuously using a plurality of threshold values corresponding to a pixel in the block of the dither mask.

11. The printing apparatus according to claim 9,

wherein, in the halftoning process, the second determination unit determines whether or not to form a dot with respect to a dot with low density.

12. A printing method in which an image is subjected to a halftoning process by setting a block, which is formed of a plurality of pixels as a unit, and is printed, the method comprising:

making a first determination which is a determination as to whether or not a gradation value of each of the plurality of pixels satisfies a predetermined condition;

making a second determination in which different conditions based on a determination result of the first determination are applied, and whether or not to form a dot in at least one of the plurality of pixels is determined;

performing a calculation of a gradation error which occurs due to a determination result of the second determination, and a distribution of the calculated error to an unprocessed pixel by setting the block as a unit; and

performing forming of a dot using a determination result of the second determination.

13. An image processing apparatus in which an image is subjected to a halftoning process by setting a block which is formed of a plurality of pixels as a unit, the apparatus comprising:

a first determination unit which determines whether or not a gradation value of each of the plurality of pixels satisfies a predetermined condition;

a second determination unit which applies different conditions based on a determination result of the first determination unit, and determines whether or not to form a dot in at least one of the plurality of pixels; and

an error calculation unit which performs a calculation of a gradation error which occurs due to a determination result of the second determination unit, and a distribution of the calculated error to an unprocessed pixel by setting the block as a unit.

14. A program in which an image is subjected to a halftoning process by setting a block which is formed of a plurality of pixel as a unit, the program causing a computer to execute:

a function of making a first determination which is a determination as to whether or not a gradation value of each of the plurality of pixels satisfies a predetermined condition;

a function of making a second determination in which different conditions based on a determination result of the first determination are applied, and whether or not to form a dot in at least one of the plurality of pixels is determined; and

a function of performing a calculation of a gradation error which occurs due to a determination result of the second determination, and performing a distribution of the calculated error to an unprocessed pixel by setting the block as a unit.