Printing apparatus, printing method, program, and image processing apparatus

• US 9,247,104 B2
• Filed: 06/04/2014
• Issued: 01/26/2016
• Est. Priority Date: 06/05/2013
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Kakutani, Toshiaki
• Primary Examiner(s): Vo, Quang N
• Application Number:
  US14/295,755
• Publication Number:
  US 20140362416A1
• Time in Patent Office: 601 Days
• Field of Search: 358/3.24, 358/1.9, 358/3.03, 358/3.06, 382/252, 714/770
• US Class Current: 1/1
• 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

Abstract

A printing apparatus includes a dot data generating section configured to: compare a first threshold which is aligned with a dither mask and a corresponding gradation value which corresponds with the image data which is input; generate the dot data by determining that dots are to be formed in a case where it is determined that the corresponding gradation value exceeds the first threshold and generate the dot data by determining the forming of dots due to application of an error diffusion method by comparing correction data, where error diffusion in the image data is complete, and a second threshold in a case where it is determined that the corresponding gradation value does not exceed the first threshold as a result of the comparing; and diffuse errors, which occur as a result of generating the dot data, to pixels in a predetermined range in the vicinity in both cases.

Claims

1. A printing apparatus adapted to print an image based on image data, the printing apparatus comprising:

an input section where the image data is input;

a dot data generating section configured to generate dot data, which represents whether or not dots are formed, based on the image data; and

a print section configured to perform printing of the image using the dot data which is generated,

wherein the dot data generating section is configured

to compare a first threshold which is aligned with a dither mask and a corresponding gradation value which corresponds with the image data which is input,

to generate the dot data by determining that dots are to be formed in a case where it is determined that the corresponding gradation value exceeds the first threshold and to generate the dot data by determining the forming of dots due to application of an error diffusion method by comparing correction data, where error diffusion in the image data is complete, and a second threshold in a case where it is determined that the corresponding gradation value does not exceed the first threshold as a result of the comparing, and

to diffuse errors, which occur as a result of generating the dot data, to pixels in a predetermined range in the vicinity in both of the cases.

2. The printing apparatus according to claim 1, wherein

the corresponding gradation value is a value which is determined by multiplying the gradation value of the image data with a predetermined coefficient.

3. The printing apparatus according to claim 2, wherein

the coefficient is determined according to the gradation value of the image data which is input.

4. The printing apparatus according to claim 3, wherein

the coefficient is a value in the vicinity of 0 when the gradation value of the image data which is input is less than a first gradation value, gradually increases substantially according to the gradation value of the image data when the gradation value of the image data which is input is equal to or more than the first gradation value and less than the second gradation value, and is a value in the vicinity of 1.0 when the gradation value of the image data which is input is equal to or more than the second gradation value.

5. The printing apparatus according to claim 3, wherein

the coefficient is a value in the vicinity of 1.0 when the gradation value of the image data which is input is less than a first gradation value, gradually decreases substantially according to the gradation value of the image data when the gradation value of the image data which is input is equal to or more than the first gradation value and less than the second gradation value, and is a value in the vicinity of 0 when the gradation value of the image data which is input is equal to or more than the second gradation value.

6. The printing apparatus according to claim 1, wherein

an alignment of the thresholds in the dither mask is an alignment where a spatial frequency, with which the formed dots are provided, is a blue noise characteristic or a green noise characteristic.

7. The printing apparatus according to claim 1, wherein

the gradation value is treated as the corresponding gradation value in the comparing by modifying the first threshold which is aligned with the dither mask.

8. A printing method, where an image is printed based on image data, comprising:

inputting the image data;

comparing a first threshold which is aligned with a dither mask and a corresponding gradation value which corresponds with the image data which is input when dot data, which represents whether or not dots are formed, is generated from the image data;

generating the dot data by determining that dots are to be formed in a case where it is determined that the corresponding gradation value exceeds the first threshold and generating the dot data by determining the forming of dots due to application of an error diffusion method by comparing correction data, where error diffusion in the image data is complete, and a second threshold in a case where it is determined that the corresponding gradation value does not exceed the first threshold as a result of the comparing;

diffusing errors, which occur as a result of generating the dot data, to pixels in a predetermined range in the vicinity in both of these cases; and

performing printing of the image using the dot data which is generated.

9. A non-transitory computer readable medium having stored thereon a program, which is realized by a computer executing functions of printing an image based on image data comprising:

inputting the image data;

comparing a first threshold which is aligned with a dither mask and a corresponding gradation value which corresponds with the image data which is input when dot data, which represents whether or not dots are formed, is generated from the image data;

generating the dot data by determining that dots are to be formed in a case where it is determined that the corresponding gradation value exceeds the first threshold and generating the dot data by determining the forming of dots due to application of an error diffusion method by comparing correction data, where error diffusion in the image data is complete, and a second threshold in a case where it is determined that the corresponding gradation value does not exceed the first threshold as a result of the comparing;

diffusing errors, which occur as a result of generating the dot data, to pixels in a predetermined range in the vicinity in both of these cases; and

performing printing of the image using the dot data which is generated.

10. An image data processing apparatus adapted to process image data, the image data processing apparatus comprising:

an input section where the image data is input; and

a dot data generating section configured to generate dot data, which represents whether or not dots are formed, from the image data which is input;

wherein the dot data generating section is configured

to compare a first threshold which is aligned with a dither mask and a corresponding gradation value which corresponds with the image data which is input,

to generate the dot data by determining that dots are to be formed in a case where it is determined that the corresponding gradation value exceeds the first threshold and to generate the dot data by determining the forming of dots due to application of an error diffusion method by comparing correction data, where error diffusion in the image data is complete, and a second threshold in a case where it is determined that the corresponding gradation value does not exceed the first threshold as a result of the comparing, and

to diffuse errors, which occur as a result of generating the dot data, to pixels in a predetermined range in the vicinity in both of these cases.

11. A printing apparatus adapted to print an image based on image data, the printing apparatus comprising:

an input section where the image data is input;

a first dot data generating section configured to generate dot data where whether or not dots are formed is provisionally determined by comparing each of thresholds in a dither mask where a plurality of thresholds are stored and a corresponding gradation value where the gradation value of the image data is multiplied with a predetermined coefficient;

a second dot data generating section configured to determine that dots are formed without any changes in a case where the provisional dot data shows a result where it is determined that dots are to be formed and determines whether or not dots are formed due to application of an error diffusion method to the image data in a case where the provisional dot data shows a result where it is determined that dots are not to be formed;

an error diffusion section configured to diffuse errors, which occur as a result of generating the dot data, to pixels in a predetermined range in the vicinity in a case where the dot data is generated according to either of the first or second dot data generation sections; and

a printing section configured to perform printing of the image using the dot data which is generated.