Image processing device

Abstract

To provide an image processing device that allows a user to obtain a color management result intended by the user without changing a color profile created on the assumption that color management processing is to be performed before overprint processing.SOLUTION: An overprint processing unit 26 performs overprint processing in which, in an object having a color plane whose color value before color management processing is 0, the color value of the color plane in the portion overlapping a rear object is overwritten with either the sum of the color value of the color plane of the same color of the rear object or the larger value of the color value of the color plane and the color value of the color plane of the same color of the rear object, and does not overwrite the color value of a color plane whose color value before color management processing is not 0.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an image processing device. [Background technology]

[0002] In an image forming apparatus that performs image processing on image data to form an image, overprinting may be performed as part of the image processing. Overprinting is a process in which a foreground object is overlaid on a background object in the image data, and the color of the foreground object is overlaid while the color of the background object remains.

[0003] When overprinting is performed on image data after color management processing according to the characteristics of the image forming device, which is the output device, there is a problem in that the overprinting process is not performed if the color value of an object changes from 0 to a value other than 0 due to the color management processing.

[0004] In response to this, Patent Document 1 discloses a technique in which image data is subjected to overprint processing and then color management processing. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-111331 Summary of the Invention [Problem to be solved by the invention]

[0006] However, with the technology of Patent Document 1, when overprinting is performed, the color values ​​of the overlapping parts of the objects change, and color management processing is performed on those changed color values. Therefore, if a color profile is created assuming that color management processing will be performed before overprinting, the color conversion of the overprinted parts may not be as expected, and the user may not be able to obtain the color management results they intended.

[0007] The present invention has been made in consideration of the above, and aims to provide an image processing device that allows a user to obtain the color management results they intend without changing a color profile that was created with the assumption that color management processing will be performed before overprint processing. [Means for solving the problem]

[0008] In order to achieve the above object, the image processing device of the present invention is characterized by comprising: a color management processing unit that performs color management processing to convert input image data including multiple color planes into output colors in accordance with the characteristics of an output device; a color value determination unit that determines whether the color value of each color plane of each object in the image data before the color management processing is 0; and an overprint processing unit that performs overprint processing to overwrite the color value of a color plane of an object having a color plane whose color value before the color management processing is 0 in a portion that overlaps with an object behind it with either the sum of the color value of the color plane of the same color of the object behind it or the larger value of the color value of the color plane and the color value of the color plane of the same color of the object behind it, without overwriting the color values ​​of color planes whose color values ​​before the color management processing are not 0. [Effects of the Invention]

[0009] According to the image processing device of the present invention, it is possible to obtain the color management results that the user intends without changing the color profile that was created on the assumption that color management processing will be performed before overprint processing. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a block diagram showing a configuration of an image forming apparatus according to an embodiment; [Figure 2] 2 is a flowchart for explaining the operation of the image forming apparatus shown in FIG. [Figure 3] FIG. 2 is a diagram illustrating an example of an original image. [Figure 4] FIG. 4 is a diagram showing an image after color management processing is performed on the original image shown in FIG. [Figure 5] 5 is a diagram showing an image obtained after overprint processing is performed on the image after color management processing shown in FIG. 4 in the image forming apparatus shown in FIG. [Figure 6] FIG. 5 is a diagram showing an image after existing overprint processing is performed on the image after color management processing shown in FIG. 4. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The same or equivalent parts and components are designated by the same or equivalent reference numerals throughout the drawings.

[0012] FIG. 1 is a block diagram showing the configuration of an image forming apparatus provided with an image processing apparatus according to an embodiment of the present invention.

[0013] As shown in FIG. 1, an image forming apparatus 1 according to the present embodiment includes an image forming unit 2 and a control unit 3.

[0014] The image forming unit 2 forms an image on a print medium such as paper. The image forming unit 2 may include, for example, a print engine having an inkjet head that ejects ink onto the print medium to perform printing.

[0015] The control unit 3 controls the overall operation of the image forming apparatus 1. The control unit 3 includes an image processing unit (corresponding to an image processing device) 11 and an image formation control unit 12. Each unit of the control unit 3 can be realized in software or hardware using a CPU, RAM, ROM, hard disk, etc.

[0016] The image processing unit 11 processes PDL (Page Description Language) data transmitted from an external personal computer or the like to generate image data, and performs image processing including color management on this image data.

[0017] The image processing unit 11 includes an interpreter unit 21, an overprint detection unit 22, a drawing processing unit 23, a color management processing unit 24, a color value determination unit 25, and an overprint processing unit 26.

[0018] The interpreter unit 21 interprets the input PDL data and converts it into intermediate data. In this embodiment, the color space of the PDL data is CMYK.

[0019] The overprint detection unit 22 detects whether or not overprinting is specified from the intermediate data.

[0020] The drawing processing unit 23 performs drawing processing according to the intermediate data and generates image data in bitmap format. This image data includes four color planes: CMYK.

[0021] The color management processing unit 24 uses a pre-prepared color profile to perform color management processing to convert the image data input from the drawing processing unit 23 into an output color in accordance with the characteristics of the output device (image forming apparatus 1). The above color profile is created on the assumption that color management processing will be performed before overprint processing.

[0022] The color value determination unit 25 performs color value determination processing to determine whether the color value of each color plane of each object in the image data before color management processing is 0 or not.

[0023] When overprinting is specified, the overprint processing unit 26 performs overprinting by overwriting the color value of a color plane of an object having a color value of 0 before color management processing in a portion that overlaps with an object behind it with either the sum of the color value of the color plane of the same color of the object behind it or the larger value of the color value of the color plane and the color value of the color plane of the same color of the object behind it, and does not overwrite the color value of a color plane whose color value before color management processing is not 0.

[0024] Here, the user can select whether the color value to be overwritten in the overprint process is the sum of the color value of the color plane of the same color of the object behind the object being overwritten, or the larger value of the color value of the color plane of the same color of the object behind the object being overwritten.

[0025] Image formation control unit 12 controls image forming unit 2 to form an image on a print medium based on image data generated and color managed by image processing unit 11. When overprint processing is performed by image processing unit 11, image formation control unit 12 controls image forming unit 2 to form an image on a print medium based on the overprinted image data.

[0026] Next, the operation of the image forming apparatus 1 will be described with reference to the flowchart of FIG.

[0027] When PDL data is input, in step S1 of FIG. 2, the interpreter unit 21 interprets the PDL data and converts it into intermediate data, and outputs this intermediate data to the overprint detection unit 22.

[0028] Next, in step S2, the overprint detection unit 22 detects whether or not overprinting is specified from the intermediate data from the interpreter unit 21. The overprint detection unit 22 outputs the detection result of whether or not overprinting is specified to the color management processing unit 24. The overprint detection unit 22 also outputs the intermediate data to the drawing processing unit 23.

[0029] Next, in step S3, the drawing processing unit 23 performs drawing processing according to the intermediate data to generate image data, and outputs this image data to the color management processing unit 24.

[0030] Next, in step S4, the color management processing unit 24 performs color management processing on the image data input from the drawing processing unit 23.

[0031] Next, in step S5, the color management processing unit 24 determines, based on the detection result from the overprint detection unit 22, whether or not overprinting is specified.

[0032] If the color management processing unit 24 determines that overprinting is specified (step S5: YES), the image data after color management processing is output to the color value determining unit 25, and the process proceeds to step S6.

[0033] In step S6, color value determination unit 25 performs color value determination processing. Specifically, color value determination unit 25 determines whether the color value before color management processing of each color plane of each object in the image data input from color management processing unit 24 is 0. Color value determination unit 25 outputs the image data after color management processing and the result of the color value determination processing to overprint processing unit 26.

[0034] Next, in step S7, overprint processing unit 26 performs overprint processing on the image data input from color value determination unit 25. Specifically, overprint processing unit 26 overwrites the color value of a color plane of an object whose color value before color management processing is 0, in a portion of the color plane that overlaps with a back object, with either the sum of the color value of the color plane of the same color of the back object, or the larger value of the color value of the color plane and the color value of the color plane of the same color of the back object, and does not overwrite the color values ​​of color planes whose color value before color management processing is not 0. Overprint processing unit 26 outputs the image data after the overprint processing to image formation control unit 12.

[0035] Next, in step S8, the image formation control unit 12 controls the image forming unit 2 to form an image on the print medium based on the image data input from the overprint processing unit 26. This completes the series of operations.

[0036] In step S5, if the color management processing unit 24 determines that overprinting is not specified (step S5: NO), the image data after color management processing is output from the color management processing unit 24 to the image formation control unit 12, and the process proceeds to step S8.

[0037] Then, in step S8, the image formation control unit 12 controls the image forming unit 2 to form an image on the print medium based on the image data input from the color management processing unit 24. This completes the series of operations.

[0038] 3 to 5 show examples of changes in color values ​​when color management processing and overprint processing are performed by the above-described operations.

[0039] 3 is a diagram showing an example of an original image. In this original image, a part of a magenta object 32 overlaps in front of a part of a cyan object 31. In addition, a part of a yellow object 33 overlaps in front of a part of the cyan object 31 and a part of the magenta object 32. In addition, there is a part where the three objects, cyan object 31, magenta object 32, and yellow object 33, overlap.

[0040] The color values ​​of each CMYK color plane in each of a cyan object 31, a magenta object 32, and a yellow object 33 in the image data of the original image are as shown in FIG.

[0041] Fig. 4 is a diagram showing an image after color management processing has been performed on the original image shown in Fig. 3. The color values ​​of each color plane in each of the cyan object 31, magenta object 32, and yellow object 33 in the image data after color management processing are as shown in Fig. 4.

[0042] Fig. 5 is a diagram showing an image after the overprint process of this embodiment has been performed on the image after the color management process shown in Fig. 4. The color values ​​of the area where two or three of the three objects (cyan object 31, magenta object 32, and yellow object 33) overlap in the image data after the overprint process are as shown in Fig. 5. In the example of Fig. 5, the color value to be overwritten in the overprint process is the sum of the color value of the color plane of the same color of the object behind the object to be overwritten.

[0043] FIG. 6 shows an image obtained after performing an existing overprint process different from that of this embodiment on the image after color management processing shown in FIG.

[0044] In the example of FIG. 6, since the color value of C of the magenta object 32 after color management processing is not 0, the magenta object 32 is not overprinted in the area E where the cyan object 31 overlaps the cyan object 31.

[0045] In contrast, in the example of FIG. 5, even if the color value of C of the magenta object 32 after color management processing is not 0, it is overprinted in area E because the color value of C of the magenta object 32 before color management processing is 0.

[0046] Furthermore, unlike the present embodiment, when color management processing is performed after overprint processing, in the example of FIG. 2, the area E where the cyan object 31 and the magenta object 32 overlap becomes 100% cyan and 100% magenta as a result of the overprint processing. Color management processing is performed on this area, but because the color management processing is performed using the color values ​​before the overprint processing, the original color values ​​converted in the color management processing have changed. For this reason, the color conversion of the overprinted area may not be as expected. As a result, the color management results intended by the user may not be obtained.

[0047] In contrast, in this embodiment, the overprint process is performed after the color management process, so even if a color profile created on the assumption that color management process will be performed before the overprint process is used, the color conversion of the overprinted part will be as expected.

[0048] As described above, in the image forming apparatus 1, the image processing unit 11 performs overprint processing after color management processing when overprinting is specified. As the overprint processing, the overprint processing unit 26 overwrites the color value of a color plane of an object whose color value before color management processing is 0 in a portion of the object that overlaps with a back object with either the sum of the color value of the color plane of the same color of the back object or the larger value of the color value of the color plane and the color value of the color plane of the same color of the back object, and does not overwrite the color values ​​of color planes whose color values ​​before color management processing are not 0. This makes it possible to obtain the color management results intended by the user without changing a color profile created with the assumption that color management processing will be performed before overprint processing.

[0049] The processing by the image processing unit 11 in the above-described embodiment may be performed by an external device such as a personal computer.

[0050] The present invention is not limited to the above-described embodiments, and the components can be modified and embodied in practice without departing from the spirit of the invention. Furthermore, various inventions can be created by appropriately combining multiple components disclosed in the above-described embodiments. For example, some components may be omitted from all the components shown in the embodiments.

[0051] [Note] The present application discloses the following inventions.

[0052] (Appendix 1) a color management processing unit that performs color management processing to convert input image data including a plurality of color planes into output colors in accordance with the characteristics of an output device; a color value determination unit that determines whether the color value of each color plane of each object in the image data before color management processing is 0; an overprint processing unit that performs overprint processing in which, in an object having a color plane whose color value before color management processing is 0, the color value of the color plane in the portion overlapping with a back object is overwritten with either the sum of the color value of the color plane of the same color of the back object or the larger value of the color value of the color plane and the color value of the color plane of the same color of the back object, and does not overwrite the color value of a color plane whose color value before color management processing is not 0; An image processing device comprising: [Explanation of symbols]

[0053] 1. Image forming device 2 Image forming unit 3. Control Unit 11 Image processing section 12 Image formation control unit 21 Interpreter 22 Overprint detection unit 23 Drawing processing unit 24 Color management processing section 25 Color value discrimination unit 26 Overprint processing section

Claims

[Claim 1] a color management processing unit that performs color management processing to convert input image data including a plurality of color planes into output colors in accordance with the characteristics of an output device; a color value determination unit that determines whether a color value of each color plane of each object in the image data before color management processing is 0; an overprint processing unit that performs overprint processing in which, in an object having a color plane whose color value before color management processing is 0, the color value of the color plane in the portion overlapping with a back object is overwritten with either the sum of the color value of the color plane of the same color of the back object or the larger value of the color value of the color plane and the color value of the color plane of the same color of the back object, and does not overwrite the color value of a color plane whose color value before color management processing is not 0; An image processing device comprising:

Images