Image processing apparatus, method of processing images, and printing apparatus to which image processing method is applied

• US 7,050,194 B1
• Filed: 11/22/1999
• Issued: 05/23/2006
• Est. Priority Date: 11/27/1998
• Status: Expired due to Fees

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Kojima, Shoji, Someno, Masahiro
• Primary Examiner(s): Garcia, Gabriel
• Assistant Examiner(s): Pham, Thierry L.
• Application Number:
  US09/444,843
• Time in Patent Office: 2,374 Days
• Field of Search: 358/1.9, 358/3.06, 358/3.13, 358/3.3, 358/3.03, 358/1.18, 358/450, 358/1.1, 358/1.11, 358/1.15, 358/252, 358/296, 382/284, 382/260, 382/267, 382/268, 382/266
• US Class Current: 358/1.9
• CPC Class Codes: H04N 1/3876 Recombination of partial images to recreate the original image
• CPC Class Codes: H04N 1/4052 by error diffusion, i.e. transferring the binarising error to neighbouring dot decisions
• CPC Class Codes: H04N 1/4055 producing a clustered dots or a size modulated halftone pattern

Abstract

A printing apparatus of the present invention prints an image corresponding to image data, which are divided into a plurality of pages and supplied from an application program, on a roll of machine glazed paper without any margin set between the adjoining pages. This arrangement enables printing on a large-sized printing medium, such as a banner. A printer driver incorporated in the printing apparatus causes the image data divided into the plurality of pages to be subjected to halftone processing according to an error diffusion method. When a standard printing mode is specified, an error buffer is initialized on every instruction of a new page. When a continuous printing mode is specified, on the other hand, the error buffer is not initialized. This causes an error occurring in a certain pixel included in one page to be diffused to pixels included in a next page in the continuous printing mode. The arrangement of the present invention enables the image data divided into a plurality of pages to be collectively processed by the halftone processing and thereby improves the picture quality of the image especially in the vicinity of a boundary between the adjoining pages.

Claims

1. An image processing apparatus that processes image data with regard to a plurality of pages by halftone processing, said image processing apparatus comprising:

an input unit that inputs the image data which has a variable length;

an image dividing unit that divides the image data into the plurality of pages each having a predetermined size;

a division data generating unit that generates division data from the plurality of pages, the division data indicating a boundary between adjacent pages; and

a halftone processing unit that performs a halftone processing on a collective set of the plurality of pages and the division data, wherein,

in a continuous mode, the halftone processing unit performs the halftone processing on each page using parameters while the parameters used in the halftone processing of a previous page are maintained beyond the boundary irrespective of the division data, and

in a standard mode, when the division data is detected, the halftone processing unit performs the halftone processing on each page using the parameters after initialization of the parameters used in the halftone processing of the previous page.

2. An image processing apparatus in accordance with claim 1, said image processing apparatus further comprising:

a mode input unit that inputs an instruction of the continuous mode, in which the image data with regard to the plurality of pages are processed as a collective set of image data,

wherein said halftone processing unit carries out the halftone processing in the state where the continuity of the processing is assured, only when the instruction of the continuous mode is input.

3. An image processing apparatus in accordance with claim 1, wherein in the continuous mode, said halftone processing unit performs the halftone processing on the image data by a unit of each pixel using an error diffusion method, the error diffusion method diffusing an error in a target pixel, to a specific pixel at a predetermined position relative to the target pixel, regardless of whether the target pixel and the specific pixel are in an identical page or different pages, the target pixel being directed to the error diffusion method, the error representing a difference between a value of the image data allocated to the target pixel and a result value of the halftone processing for the target pixel.

4. An image processing apparatus in accordance with claim 3, wherein said input unit inputs an instruction of the continuous mode, in which the image data with regard to the plurality of pages are processed as a collective set of image data, as well as page division data, and

said halftone processing unit comprises:

an error storage unit that temporarily stores diffused errors;

an initialization unit that carries out initialization of said error storage unit in response to an input of the page division data; and

a prohibition unit that prohibits the initialization of said error storage unit when the instruction of the continuous mode is input.

5. An image processing apparatus in accordance with claim 1, wherein in the continuous mode, said halftone processing unit carries out the halftone processing according to a dither method, which allows a dither matrix to be arranged across the boundary between the adjoining pages.

6. An image processing apparatus in accordance with claim 5, wherein said input unit inputs a specification of a continuous mode, in which the image data with regard to the plurality of pages are processed as a collective set of image data, as well as page division data, and

said halftone processing unit comprises:

an allocation storage unit that stores an allocation of the dither matrix to pixels;

an initialization unit that carries out initialization of said allocation storage unit in response to an input of the page division data so as to set the allocation of the dither matrix to a predetermined state in each page; and

a prohibition unit that prohibits the initialization of said allocation storage unit when the instruction of the continuous mode is input.

7. A printing apparatus that creates dots based on image data with regard to a plurality of pages and thereby prints an image on a specific printing medium, which has a size of or over the plurality of pages, said printing apparatus comprising:

an input unit that inputs the image data which has a variable length;

an image dividing unit that divides the image data into the plurality of pages each having a predetermined size;

a division data generating unit that generates division data from the plurality of pages, the division data indicating a boundary between adjacent pages;

a halftone processing unit that performs a halftone processing on a collective set of the plurality of pages and the division data, wherein,

in a continuous mode, the halftone processing unit performs the halftone processing on each page using parameters while the parameters used in the halftone processing of a previous page are maintained beyond the boundary irrespective of the division data, and

in a standard mode, when the division data is detected, the halftone processing unit performs the halftone processing on each page using the parameters after initialization of the parameters used in the halftone processing of the previous page; and

a dot creation unit that creates a dot in each pixel, based on a result of the halftone processing.

8. A method of processing image data with regard to a plurality of pages by halftone processing, said method comprising the steps of:

inputting the image data which has a variable length;

dividing the image data into the plurality of pages each having a predetermined size;

generating division data from the plurality of pages, the division data indicating a boundary between adjacent pages; and

performing a halftone processing in a continuous mode on a collective set of the plurality of pages and the division data and on each page using parameters while the parameters used in the performing the halftone processing of a previous page are maintained beyond the boundary irrespective of the division data, and

performing a halftone processing in a standard mode on each page using the parameters after initialization of the parameters used in the halftone processing of the previous page when the division data is detected.

9. A computer readable medium, in which a specific computer program is recorded, said specific computer program being used to process image data with regard to a plurality of pages by halftone processing, said specific computer program comprising:

a program code that causes a computer to input the image data which has a variable length;

a program code that causes the computer to divide the image data into a plurality of pages each having a predetermined size;

a program code that causes the computer to generate division data from the plurality of pages, the division data indicating a boundary between adjacent pages;

a program code that causes the computer to perform a halftone processing in a continuous mode according to an error diffusion method on a collective set of the plurality of pages and the division data, wherein the halftone processing is performed on each page using parameters while the parameters used in the halftone processing of a previous page are maintained beyond the boundary irrespective of the division data; and

a program code that causes the computer to perform a halftone processing in a standard mode on each page according to the error diffusion method using the parameters after initialization of the parameters used in the halftone processing of the previous page when the division data is detected.

10. A computer readable medium, in which a specific computer program is recorded, said specific computer program being used to process image data with regard to a plurality of pages by halftone processing, said specific computer program comprising:

a program code that causes a computer to input the image data which has a variable length;

a program code that causes the computer to divide the image data into a plurality of pages each having a predetermined size;

a program code that causes the computer to generate division data from the plurality of pages, the division data indicating a boundary between adjacent pages;

a program code that causes the computer to perform a halftone processing in a continuous mode according to a dither method on a collective set of the plurality of pages and the division data, wherein the halftone processing is performed on each page using parameters while the parameters used in the halftone processing of a previous page are maintained beyond the boundary irrespective of the division data; and

a program code that causes the computer to perform a halftone processing in a standard mode on each page according to the dither method using the parameters after initialization of the parameters used in the halftone processing of the previous page when the division data is detected.