KR100434901B1 - Method of generating black-and-white print image set up in type using cmyk color image - Google Patents

Abstract

Disclosed is a method of generating a black and white image before starting typesetting through a color image generated by a scan job and separately processing a color typesetting surface and a black and white typesetting surface. This improves the print quality of black and white paper by solving in advance the potential problems that can occur after processing color images into black and white images. The present invention provides a method for generating a black and white typesetting surface image for printing using a color image separated by a CMYK color space, the method comprising: generating a black and white image using a CMYK color image, and using a generated black and white image Generating a surface; and generating a monochrome typesetting surface image for printing using the generated monochrome typesetting surface.

Description

METHODS OF GENERATING BLACK-AND-WHITE PRINT IMAGE SET UP IN TYPE USING CMYK COLOR IMAGE}

The present invention relates to a method for printing a black and white image using a color image, and more particularly, to a method for generating a black and white typesetting surface image for printing using a color image separated in a CMYK color space and printing it on the ground.

A person who wants to advertise in a newspaper or the like usually submits a photographic film generated by separating the advertisement content into a CMYK color space to a newspaper company and requests an advertisement. The newspaper company scans the photographic film to produce a printing typesetting surface image, and transfers the generated typesetting surface image to the film and finally prints it on the ground.

'CMYK' is a kind of color model. It consists of cyan, magenta, yellow and black, and is a standard color model used to synthesize colors in printing devices such as printers. . Arbitrary colors are represented by a mixture of four colors of ink: shiyan, magenta, yellow and black. Theoretically, all three colors, including black, can be expressed by mixing inks of three colors, shiyan, magenta, and yellow, but black is added because the pigments of the ink do not show proper black color. The color model that contrasts with CMYK is the RGB commonly used in display devices. 'RGB' consists of red, green, and blue.

Fig. 1 is a flowchart up to film transfer when the color image and the black and white image are all equipped. As shown in FIG. 1, when both color film and black and white film for an advertisement image are provided, a printing typesetting image is separately generated for each, and transferred to the film.

In detail, first, when a color film for an advertisement image is provided, it is scanned to generate a 1 bit / sample TIFF file separated into a CMYK color space (102). A sample is a minimum unit to be printed. Thus, 1 bit / sample means that the minimum printing unit is represented by only 1 bit having "0" or "1". Tag Image File Format (TIFF) is a common format for exchanging raster images between applications, including scanning images. A color typesetting surface is generated by attaching the generated TIFF file according to the layout plan of the newspaper page (104). Color typesetting surfaces are typically generated as files in EPS (Encapsulated Post Script) format. Next, a printing color typesetting image having a TIFF format of 1 bit / sample is generated through a process called "ripping" from the generated color typesetting surface (106). A color typesetting image for printing is created, one for each CMYK, so all four are produced.

A black and white typesetting image for printing is also generated through the same process as a color typesetting surface image for printing. That is, if a black and white film is provided, the generated black and white film is scanned to generate a 1 bit / sample TIFF file (108), and the created TIFF file is pasted according to the layout plan of the newspaper paper to produce a black and white typesetting surface in EPS format. In operation 110, a printing black and white typesetting image having a TIFF format of 1 bit / sample is generated through a ripping process (112). As described above, four color printing typesetting images are made for each CMYK, but only one printing type black and white typesetting image is made. The printing color typesetting surface image and the black and white typesetting surface image for printing are transferred onto the film (114) and printed on the ground.

1 is a case where both the color film and the black and white film are provided for the same image, as described above, the printing color typesetting surface image and the printing monochrome typesetting surface image are generated through separate procedures. However, often only one color film is provided and printed on the ground in two forms, color and black and white. In this case, a black and white print is made using color film.

2 is a flow chart up to conventional film transfer in the absence of a black and white image. In the case where both the color film and the black and white film for the advertisement image are provided in FIG. 1, a process of generating a color typesetting image for printing and a black and white typesetting image for printing is shown. In FIG. 2, only the color film without the black and white film is shown. If provided, the process of generating a color typesetting image for printing and a black and white typesetting image for printing is shown. In FIG. 2, the color image generation 202, the color typesetting surface 204, and the film transfer 208 are the same as those of FIG. 1, but the black and white film is not provided in the first step. A typesetting surface image for printing is generated using the typesetting surface (206). This is distinguished from the process of FIG. 1.

3 is a flowchart for generating a color typesetting surface image for printing and a black and white typesetting surface image for printing as a color typesetting surface. As shown in Fig. 3, a process of generating an image for printing having a TIFF format of 1 bit / sample using a color typesetting surface in EPS format is called so-called ripping. The color typesetting surface of the EPS format generated in step 302 through this ripping process 304 is made of four 1-bit / sample TIFF images that cover each color space of CMYK according to the ground plan (308), It is made of one 1 bit / sample TIFF image for monochrome printing (306). The black and white typesetting image for printing produces a black and white surface similar to the color surface using only brightness information except saturation among four C, M, Y, and K color spaces.

However, when generating a black and white typesetting surface image for printing using the color film as described above, printing on the black and white paper using this will cause some problems. First, it predicts the color ground and processes or typesets the image, so that by placing colors with the same or similar brightness side by side, the color to be distinguished from the black and white ground is not distinguished, and thus it is impossible to represent the expected form of the ground. Occurs. In addition, it is difficult to know such a potential problem until it is printed on the ground, which causes a considerable difficulty in planning the black and white ground. In fact, we are receiving claims from an ad client regarding this matter.

The present invention is derived from the process for solving such a problem, even when generating a black and white typesetting surface image for printing using a color film, and using it to print on a black and white paper surface of the black and white paper before actually printed on the paper in advance It is an object to improve the print quality of black and white paper by knowing the shape.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a flow chart up to film transfer when color images and black and white images are all equipped.

2 is a flow chart up to conventional film transfer in the absence of a black and white image.

3 is a flowchart for generating a color typesetting image for printing and a black and white typesetting image for printing with a color typesetting surface.

Figure 4 is a flow chart for printing a black and white image on the ground through the color image according to the present invention.

5 is a flowchart of a process of converting a color image into a black and white image according to an embodiment of the present invention.

6 is a flow chart up to film transfer according to the present invention.

In connection with this purpose, a method of processing a color typesetting surface and a black and white typesetting surface separately by generating a black and white image before starting typesetting through a color image generated by a scanning operation is disclosed. This improves the print quality of black and white paper by solving potential problems that may appear after processing color images into black and white images.

The present invention provides a method for generating a black and white typesetting surface image for printing using a color image separated by a CMYK color space, the method comprising: generating a black and white image using a CMYK color image, and using a generated black and white image And generating a black and white typesetting surface image for printing using the generated black and white typesetting surface.

Preferably, the CMYK color image is in TIFF format in which one sample is represented by one bit. The generating of the black and white image may include converting the CMYK color image into a TIFF format in which one sample is represented by N bits (N ≥ 2), multiplying the converted CMYK color image by a predetermined weight, and averaging each sample. And generating gray scale TIFF data in which one sample is represented by N bits, and performing halftoning on the gray scale TIFF data so that one sample is represented by one bit. The N bits are preferably 8 bits.

The generating of the gray scale TIFF data may be performed by generating an RGB color image from the CMYK color image, and multiplying and averaging the data of the RGB color image by a predetermined number with respect to each sample. have.

In addition, the present invention is a method for printing a black and white image using a color image separated in the CMYK color space, generating a black and white image using the CMYK color image, and using the generated black and white image Generating a black and white typesetting surface image for printing using the generated black and white typesetting surface, transferring the generated black and white typesetting surface image to a film, and printing on the ground using the transferred film It is another feature that comprises the step of.

In addition, the present invention is a method for generating a black and white image using a CMYK color image of TIFF format in which one sample is represented by one bit, the CMYK color image in a TIFF format in which one sample is represented by N bits (N ≥ 2) Converting, multiplying the converted CMYK color image by a predetermined weight and averaging each sample to generate gray scale TIFF data in which one sample is represented by N bits, and half-toning the gray scale TIFF data. and a step of performing halftoning so that one sample is represented by one bit.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention; In the drawings, the same reference numerals are used to refer to the same or similar components and signals for the sake of consistency of description.

4 is a flowchart of printing a black and white image on the ground through a color image according to the present invention. In the conventional method illustrated in FIG. 2, the black and white typesetting surface image for printing is generated using the generated color typesetting surface, whereas the black and white printing is generated in the present invention shown in FIG. 4. Therefore, it distinguishes from each other in that it prints black and white. When a black and white image is generated using a color image created through a scanning operation as in the present invention, a black and white sheet having a good quality can be printed since a black and white typesetting surface image is transferred to a film by printing on a black and white sheet. .

In detail, referring to FIG. 4, first, a color image generated through a scan operation is first generated (402). The color image consists of four 1-bit / sample TIFF images separated in CMYK color space. Next, a black and white image is generated using the generated color image (404). A detailed process thereof will be described below with reference to FIG. 5. The process of generating a black and white typesetting surface using the generated black and white image (406), generating a black and white typesetting surface image for printing (408), and transferring (410) to the film is the same as described with reference to FIG. FIG. 4 further illustrates a process 412 of printing a black and white typesetting image on the ground using the transferred film.

5 is a flowchart illustrating a process of converting a color image into a black and white image according to an embodiment of the present invention. As described above, the color image generated by the scan job has a TIFF format, and is generated for each CMYK and is composed of four pieces. Each image of CMYK is generated 1 bit / sample at 1270 dpi (dot per inch). This color image is converted into one monochrome image having 1 bit / sample at 1270 dpi through the process of FIG.

Specifically, referring to FIG. 5, this color image is first converted into a TIFF image in which one sample is represented by 8 bits for each CMYK (502). That is, if the bit of a sample is "0", it is converted into "00000000", and if it is "1", it is simply converted into "11111111". Next, one RGB image of TIFF format in which one sample is represented by 24 bits is generated (504). In order to convert to an RGB image having a 24-bit / sample TIFF format using the four 8-bit / sample images generated above, the CMYK color space must be converted to an RGB color space. So it is done.

C (8 bit)-K (8 bit) = R (8 bit)

M (8 bit)-K (8 bit) = G (8 bit)

Y (8 bit)-K (8 bit) = B (8 bit)

R, G, and B data having 8 bits for each sample can be simply juxtaposed for each sample to produce one RGB image in which one sample is represented in a 24-bit TIFF format. Next, a gray scale image of a TIFF format in which one sample has 8 bits is generated using the one RGB image thus generated (506). To this end, the following Equation 2 is performed for each sample. In Equation 2, R, G, and B are 8 bits of data corresponding to each sample. ">> 8" indicates an operation of shifting 8 bits to the right.

Sum = R × 28 × 255/100 + G × 59 × 255/100 + B × 11 × 255/100

Result = Sum >> 8

The result of the calculation is the sum of 28% of R, 59% of G, and 11% of B, represented by 8 bits. These weights are intended to ensure good distinction between relatively adjacent colors in the resulting grayscale TIFF image, even for images planned for color space. Next, a half-toning process is performed on a grayscale image having an 8-bit / sample TIFF format to generate a 1-bit / sample TIFF image (508). The TIFF file created above must be converted to a 1 bit / sample TIFF file to be used for actual film transfer. This process is called halftoning. The basic process of halftoning is 1 if the 8-bit value corresponding to each sample is greater than 127, or 0 if it is less than 127, but the resulting error (that is, the original grayscale value and the converted 1-bit sample). This is done by dividing the difference between the value of and multiplied by 255 by surrounding samples. When dividing the error, it is desirable to divide by 7/16 to the right, 3/16 to the left, 5/16 to the bottom, and 1/16 to the left. Expressed as an equation, the value P (X, Y) to be transformed for a sample at any position (X, Y) (where 0 ≦ X ≦ image width and 0 ≦ Y ≦ image height) is Equation 3 Where I (X, Y) points to an 8-bit TIFF value at position (X, Y), and TRUNC (X) is 1 if X ≥ 127 and 0 if X <127.

P (X, Y) = TRUNC {

(7/16) × [I (X-1, Y) -P (X-1, Y) × 255]

+ (1/16) × [I (X-1, Y-1) -P (X-1, Y-1) × 255]

+ (5/16) × [I (X, Y-1) -P (X, Y-1) × 255]

+ (3/16) × [I (X + 1, Y-1) -P (X + 1, Y-1) × 255]

+ I (X, Y)}

In other words, it is a method of receiving an error value from four samples to give an error to itself and adding it to its own value to obtain a value of 1 bit / sample. The created 1 bit / sample TIFF file is similarly generated at 1270 dpi because the CMYK TIFF file used is 1270 dpi. This is the same as scanning a black and white image, so typesetting the black and white ground.

6 is a flowchart up to film transfer according to the present invention. A process 606 of generating a black and white image using a color image generated through a scan operation through the processes illustrated in FIGS. 4 and 5 is further included in comparison with FIG. 1. The other process is the same as the corresponding process shown in FIG. Therefore, detailed description of each process will be omitted here.

The embodiments described herein have been described in particular as an example of printing an advertisement image on a paper such as a newspaper, but is not limited to this case, and the same applies to the case of printing any image on any paper. These examples are only intended to enable those skilled in the art to easily understand and to practice the present invention, and are not intended to limit the scope of the invention. Therefore, those skilled in the art should note that various modifications or changes are possible within the scope of the present invention. The scope of the invention is defined in principle by the claims that follow.

According to the configuration of the present invention, it is possible to improve the print quality of the black and white paper by solving the potential problems that may appear after processing the color image into a black and white image.

Claims (13)

In the method for generating a black and white typesetting image for printing using a color image separated in the CMYK color space, Generating a black and white image using a CMYK color image, Generating a black and white typesetting surface by using the generated black and white image; Generating a monochrome typesetting surface image for printing using the generated monochrome typesetting surface A black and white typesetting image generation method for printing comprising a. The method of claim 1, And the CMYK color image is a TIFF format in which one sample is expressed in one bit. The method of claim 2, The black and white image generation step Converting the CMYK color image into a TIFF format in which one sample is represented by N bits (N ≥ 2); Multiplying the converted CMYK color image by a predetermined weight and averaging each sample to generate gray scale TIFF data in which one sample is represented by N bits; Half-toning the gray scale TIFF data so that one sample is represented by one bit. A black and white typesetting image generation method for printing comprising a. The method of claim 3, wherein And the N bits are 8 bits. The method of claim 3, wherein The process of generating the gray scale TIFF data Generating an RGB color image from the CMYK color image; For each sample, the process of multiplying and averaging the data of the RGB color image by a predetermined number A black and white typesetting image generation method for printing comprising a. In the method for printing a black and white image using a color image separated in the CMYK color space, Generating a black and white image using a CMYK color image, Generating a black and white typesetting surface by using the generated black and white image; Generating a monochrome typesetting surface image for printing using the generated monochrome typesetting surface; Transferring the generated black and white typesetting image onto a film; Printing on the ground using the transferred film Black and white image printing method comprising the. The method of claim 6, And the CMYK color image is a TIFF format in which one sample is expressed in one bit. The method of claim 7, wherein The black and white image generation step Converting the CMYK color image into a TIFF format in which one sample is represented by N bits (N ≥ 2); Multiplying the converted CMYK color image by a predetermined weight and averaging each sample to generate gray scale TIFF data in which one sample is represented by N bits; Half-toning the gray scale TIFF data so that one sample is represented by one bit. A black and white typesetting image generation method for printing comprising a. The method of claim 8, And the N bits are 8 bits. The method of claim 8, The process of generating the gray scale TIFF data Generating an RGB color image from the CMYK color image; For each sample, the process of multiplying and averaging the data of the RGB color image by a predetermined number A black and white typesetting image generation method for printing comprising a. In the method for generating a black and white image using a CMYK color image of TIFF format in which one sample is represented by 1 bit, Converting the CMYK color image into a TIFF format in which one sample is represented by N bits (N ≧ 2), Generating gray scale TIFF data in which one sample is represented by N bits by multiplying the converted CMYK color image by a predetermined weight and averaging each sample; Performing halftoning on the gray scale TIFF data so that one sample is represented by one bit. Black and white image generating method comprising the. The method of claim 11, And the N bits are 8 bits. The method of claim 11, The process of generating the gray scale TIFF data Generating an RGB color image from the CMYK color image; For each sample, the process of multiplying and averaging the data of the RGB color image by a predetermined number Black and white image generating method comprising the.