JP5666356B2 - Image processing apparatus, image forming apparatus, image processing method, program, and recording medium - Google Patents

Description

  The present invention relates to an image processing apparatus, an image forming apparatus, an image processing method, a program, and a recording medium that create a combined image by combining a composition image with a document image.

  2. Description of the Related Art In recent years, the copying accuracy of image forming apparatuses that perform copying has improved, so that original images such as documents can be easily copied and reproduced with high accuracy. In such a high-performance image forming apparatus, for example, illegal copying such as copying a specific document image that should be prohibited from copying to create an illegal copy is easily performed. Therefore, in order to prevent illegal copying of a specific document image, a technique for synthesizing a copy protection pattern, a watermark character, or the like with a specific document image has been realized.

  For example, in Patent Document 1, the background portion of the input image and the warning character portion to be combined with the background portion have a common density, and different dither processing is applied to the background portion and the warning character portion. A technique for creating a combined image by combining two images is disclosed.

  In this technique, in the original document image, the warning character portion and the background portion are dots having a constant area ratio. For this reason, the warning character portion and the background portion look almost uniform in density with the difference in the number of lines of halftone dots being inconspicuous with the naked eye. That is, the warning character part is hidden behind the background part and appears as a gray image area as a whole. On the other hand, when the synthesized image is copied, the number of lines of halftone dots is different between the warning character portion and the background portion, so that an image having a moire difference (warning character portion) appears on the recording paper. Therefore, the synthesized image has the same function as the copy forgery prevention paper.

  Patent Document 2 discloses an image forming apparatus having a tint block embedding function for embedding a latent image pattern in a copy. The latent image pattern is not visible on the first copy obtained by copying the original, but is visible on the second copy obtained by copying the first copy as the original. Appears possible. In this image forming apparatus, by using the tint block embedding function, a latent image pattern is embedded in the first copy, and a pattern having a predetermined shape representing instruction information for executing a specific process is included in the latent image pattern. It has become.

Japanese Patent Laid-Open No. 7-231384 (released on August 29, 1995) Japanese Unexamined Patent Publication No. 2007-20067 (released on January 25, 2007)

  Here, it is customary to stamp a variety of documents in private companies and the public sector, especially contracts and official documents. Such a document is difficult to distinguish from the original (original) especially when copied by color printing. Therefore, in order to prevent forgery, a warning character or a warning pattern is embedded as a background pattern in the original (original). According to such a technique, a copy-forgery-inhibited pattern (warning character or warning pattern) appears at the time of copying. Further, since warning characters and warning patterns can be visually recognized even in a document before copying, an effect of psychologically suppressing or checking copying itself can be obtained.

  On the other hand, when a color document is copied by monochrome printing to obtain a copy, it is easy to distinguish the copy from the document. Therefore, when a document is printed in monochrome, it is generally unnecessary to embed a counterfeit for preventing counterfeiting in the document or copy.

  In the technique of Patent Document 1, the warning character portion is embedded in the synthesized image as a synthesis image, so that an effect of suppressing copying from the synthesized image can be obtained. In addition, when copying a composited image, it is possible to easily detect an embedded composite image visually.

  On the other hand, in the copy of the composited image, the composite image visually appears. As a result, the composite image is easily visually recognized and the copied image is difficult to see. For example, a monochrome printed image or a FAX received image has a low need for visually appearing a warning character portion (compositing image) because it is easy to distinguish between a copy and an original as described above. is there. In spite of such circumstances, when a warning character part (compositing image) appears in a copy image (for example, a monochrome copy image) that makes it easy to distinguish between a copy and an original, The legibility is significantly reduced.

  In the technique of Patent Document 2, the latent image pattern is not visible on the first copy of the original image. However, in the second copy obtained by further copying the first copy. Appears visually. Therefore, it is possible to maintain a state in which the original image is easy to see with the first copy, and it is possible to prevent leakage of confidential information by copying the first copy.

  However, as in the technique of Patent Document 1, as a result of the latent image pattern appearing in the second copy, a copy image (for example, a monochrome copy image) that has a low need for visual appearance of the latent image pattern is an image. The visibility will be significantly reduced.

  Accordingly, an object of the present invention is to provide an image forming apparatus and an image forming method capable of switching between the visualization and non-imaging of the composite image in the copy image of the composite image obtained by combining the composite image. Yes.

  In order to solve the above problems, an image processing apparatus according to the present invention includes a composition processing unit that composes a composition image in a composition image composition region of a document image to create a composite image, and a color input image. And a color conversion processing unit that performs a first mode process for reproducing the color of the input image and a second mode process for converting the color of the input image by the first color conversion process. The synthesis processing unit is configured to process the second mode on the synthesized image by the color conversion processing unit when a color signal value of the synthesis image is different from a color signal value of the synthesis image synthesis region. Is performed, as a result of the first color conversion process, the second color conversion process in which the color signal value of the image synthesis area for synthesis in the document image is equivalent to the color signal value of the image for synthesis Is applied to the composition image, and the original image is It is characterized by synthesizing the serial synthesis image.

  The image processing method of the present invention also includes a composition processing step of compositing a composition image in a composition image composition region of a document image to create a composite image, and the color of the input image with respect to the color input image. In the image processing method comprising: a first mode process to be reproduced; and a color conversion process step of performing a second mode process of converting the color of the input image by the first color conversion process. When the color signal value of the image for synthesis is different from the color signal value of the image synthesis area for synthesis and the process of the second mode is performed on the synthesized image by the color conversion processing step, As a result of the first color conversion process, the composition image is subjected to a second color conversion process in which the color signal value of the composition image composition area in the document image is equivalent to the color signal value of the composition image. , The composition image is added to the document image. It is characterized in that formed.

  According to the above configuration, the composition processing unit (in the composition processing step) has a color signal value of the composition image different from the color signal value of the composition image composition region, and a color conversion processing unit (color conversion processing step). As a result of the first color conversion processing, the color signal value of the composition image composition area and the color signal value of the composition image in the original image are obtained as a result of the first color conversion processing. The equivalent second color conversion process is performed on the composition image, and the composition image is synthesized with the document image.

  Thereby, when the process of the first mode is selected for the synthesized image, the synthesis image is visualized in the processed synthesized image. On the other hand, when the second mode processing is selected for the synthesized image, the synthesis image is made non-visualized in the processed synthesized image. Therefore, by selecting a process to be performed on the synthesized image from among the first mode process and the second mode process, visualization and non-imaging of the synthesis image in the synthesized image are performed. Can be switched.

  In the image processing apparatus, the color conversion processing unit performs a process of converting a luminance signal of a color of the input image into a grayscale luminance signal in the first color conversion process, and the composition processing unit In the second color conversion processing, as a result of the first color conversion processing, conversion is performed from the grayscale luminance signal converted from the luminance signal of the color of the image for composition synthesis and the luminance signal of the color of the image for synthesis. Color conversion processing in which the grayscale luminance signal is the same as the grayscale luminance signal, and the luminance signal of the color of the composition image is a luminance signal of a color different from the luminance signal of the color of the composition image composition area of the document image It is good also as a structure which performs with respect to the said image for a synthesis | combination.

  According to said structure, a color conversion process part performs the process which converts the luminance signal of the color of an input image into a gray scale luminance signal in a 1st color conversion process. In the second color conversion process, the synthesis processing unit uses the grayscale luminance signal converted from the color luminance signal of the synthesis image synthesis area and the color luminance signal of the synthesis image as a result of the first color conversion process. The color conversion processing is performed so that the converted grayscale luminance signal is the same, and the luminance signal of the color of the image for synthesis becomes a luminance signal of a color different from the luminance signal of the color of the image for synthesis To do.

  Thus, when the first mode processing is selected for the color synthesized image, the synthesized image is reproduced as a color image, and the synthesized image is visualized in the processed synthesized image. Is done. On the other hand, when the second mode processing is selected for the color composite image, the composite image is processed into a monochrome image, and the composite image is de-imaged in the processed composite image. The Therefore, by selecting a process to be performed on the synthesized image from among the first mode process and the second mode process, visualization and non-imaging of the synthesis image in the synthesized image are performed. Can be switched.

  In this case, in the second mode processing for processing the combined image into a monochrome image, the combining image is made non-visualized. Therefore, in the monochrome image that can be easily distinguished from the color original image, the combining image is unnecessarily necessary. This makes it possible to prevent the situation in which the original image is difficult to see.

  The image processing apparatus includes a composite image density input unit that specifies a density of the composite image in the composited image, and the composite processing unit is configured to perform the composite processing when the processing in the first mode is performed. The third color conversion processing for setting the luminance signal of the color of the image for synthesis may be performed so that the density of the image for synthesis in the image becomes a density according to the input from the synthesized image density input unit. Good.

  According to the above configuration, the density of the image for synthesis in the synthesized image when the first mode processing for reproducing the color of the synthesized image is performed can be made to the user's preference by the input from the synthesized image density input unit. It can be set arbitrarily depending on the situation.

  According to the configuration of the present invention, the composition processing unit (in the composition processing step) is such that the color signal value of the composition image is different from the color signal value of the composition image composition region and the color conversion processing unit (color conversion processing step). ), When the second mode process is performed on the synthesized image, the color signal value of the synthesis image synthesis area and the color signal value of the synthesis image in the original image are obtained as a result of the first color conversion process. A second color conversion process in which is equivalent to is performed on the composition image, and the composition image is synthesized with the document image.

  Thereby, when the process of the first mode is selected for the synthesized image, the synthesis image is visualized in the processed synthesized image. On the other hand, when the second mode processing is selected for the synthesized image, the synthesis image is made non-visualized in the processed synthesized image. Therefore, by selecting a process to be performed on the synthesized image from among the first mode process and the second mode process, visualization and non-imaging of the synthesis image in the synthesized image are performed. Can be switched.

FIG. 1 is a block diagram showing a configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is an explanatory diagram illustrating a basic screen of an operation panel included in the image forming apparatus illustrated in FIG. 1. 3 is a flowchart showing a composition process in a color correction / black generation unit shown in FIG. 1. FIG. 4 is a flowchart showing the contents of processing of a color correction / black generation unit for a read combined image obtained by scanning a printed image obtained by printing a combined image created by the processing of FIG. 3. It is explanatory drawing which shows an example of the synthetic | combination process in the color correction and black production | generation part shown in FIG. 1 with a specific image. FIG. 6 is an explanatory diagram of an example in which a compositing image appears or disappears due to processing on a read composited image acquired by scanning the composited image print image illustrated in FIG. It is explanatory drawing of the process which adjusts the degree of visualization of the image for a synthesis | combination in the color correction and the black production | generation part of the image processing apparatus in other embodiment of this invention.

[Embodiment 1]
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram illustrating a configuration of an image forming apparatus 100 according to an embodiment of the present invention. As shown in FIG. 1, the image forming apparatus 100 includes a color image input device 200, a color image processing device 300, and a color image output device 400.

  The color image input device 200 inputs a document image signal to the color image processing device 300. When the color image input device 200 is composed of a scanner, for example, the color image input device 200 scans a document image with a light source, reads a reflected light image from the document image with a CCD (Charge Coupled Device), and performs RGB (R: red). , G: green, B: blue) A document image signal composed of an analog signal is acquired. When the color image input device 200 is composed of, for example, a PC (personal computer), the color image input device 200 transmits an RGB image signal as a document image signal to the color image processing device 300 via a printer driver.

  The color image output apparatus 400 is an apparatus that outputs a document image signal that has been subjected to predetermined image processing by the color image processing apparatus 300, and is, for example, a printer.

  A color image processing apparatus 300 includes an A / D (analog / digital) conversion unit 10, a shading correction unit 11, a document type automatic discrimination unit 12, an input tone correction unit 13, a region separation processing unit 14, a color correction / black generation unit. 15, a spatial filter processing unit 16, an output tone correction unit 17, a tone reproduction processing unit 18, and a storage unit 19.

  The A / D converter 10 converts an analog document image signal input from the color image input device 200 into a digital document image signal.

  The shading correction unit 11 removes various distortions generated in the illumination system, imaging system, and imaging system of the color image input device 200 from the RGB document image signal input from the A / D conversion unit 10. I do.

  The document type automatic discrimination unit 12 uses an RGB signal (RGB reflectance signal) as a document image signal from which various distortions have been removed by the shading correction unit 11 in the color image processing apparatus 300. It is converted into a density signal that is easy to handle. Thereafter, the document type for the document image signal is determined. In the determination of the document type, it is determined whether the document image indicated by the document image signal is, for example, a character document, a photographic document, or a character / photo document combining them.

  The input tone correction unit 13 adjusts the color balance of the document image signal. At the same time, based on the determination result of the document type automatic determination unit 12, image quality adjustment processing for adjusting the background density, contrast, and the like is performed on the document image signal.

  The region separation processing unit 14 separates the document image indicated by the document image signal into a character, halftone dot, or photographic region for each pixel based on the determination result of the document type automatic determination unit 12. Further, a composition image to be synthesized with the document image is also separated as a composition image area. Further, the region separation processing unit 14 outputs a region identification signal indicating which region each pixel belongs to based on the result of separating each pixel of the document image, the color correction unit / black generation unit 15, and the spatial filter processing unit. 16 and the gradation reproduction processing unit 18.

  The color correction / black generation unit 15 converts the RGB signal values in the original image signal into spectral characteristics of CMYK (C: cyan, M: magenta, Y: yellow, K: black) color materials for faithful color reproduction. Is converted into a four-color signal based on the above. Thereafter, the color correction / black generation unit 15 refers to the composition image stored in the storage unit 19 when an instruction to synthesize the composition image with the document image is input, and synthesizes the document image. An image for image synthesis is performed, thereby creating a synthesized image.

  The composition image holds the position information of the composition image composition area in the original image, that is, the composition image composition area. Therefore, the color correction / black generation unit 15 refers to the position information held by the composition image in the composition processing, composes the composition image in the composition image composition area, and creates a composited image.

  The spatial filter processing unit 16 performs spatial filter processing using a digital filter on the document image signal (combined image signal) processed by the color correction / black generation unit 15 to correct the spatial frequency characteristics. Thereby, sharpness enhancement and moire improvement of the output image are performed.

  The output tone correction unit 17 performs output tone correction processing for converting a signal such as a density signal into a halftone dot area ratio that is a characteristic value of the color image output device 400.

  As the halftone generation process, the gradation reproduction processing unit 18 finally divides the original image signal (combined image signal) for each pixel and performs processing so that the gradation of each pixel can be reproduced.

  For the image area extracted as a black character or a color character by the area separation processing unit 14, the spatial filter processing unit 16 uses a high-frequency sharpness enhancement process to improve the reproducibility of the black character or the color character area. Increase the amount of emphasis. At the same time, in the halftone generation process in the gradation reproduction processing unit 18, a binarization process or a multi-value process on a high resolution screen suitable for high frequency reproduction is selected.

  On the other hand, for the region extracted as a halftone dot by the region separation processing unit 14, the spatial filter processing unit 16 performs low-pass filter processing for removing the input halftone component. At the same time, in the halftone generation process in the gradation reproduction processing unit 18, binarization or multilevel conversion is performed on the screen with an emphasis on gradation reproducibility.

  The document image signal (combined image signal) that has been subjected to each processing in this way is stored in the storage unit 19, read at a predetermined timing, and input to the color image output device 400.

  The color image output apparatus 400 is a printer that prints image data on a recording sheet, and is, for example, an electrophotographic system or an inkjet system. In addition, the process in each part is controlled by the control part 600 which consists of CPU (Central Processing Unit).

  The image forming apparatus 100 also includes an operation panel 40 for inputting instructions from the user. FIG. 2 is an explanatory diagram showing a basic screen of the operation panel 40. The operation panel 40 is of a touch panel type, for example, and displays various buttons on the basic screen as shown in FIG. Specifically, a composite image density adjustment button 45 is provided, and a copy button 41, an image transmission button 42, a document filing button 43, and other buttons are further provided.

  The composite image density adjustment button 45 is used to adjust (select) the density of the composite image when the composite image is combined with the original image. In the image forming apparatus 100, that is, the color image processing apparatus 300, for example, the operation of pressing the composite image density adjustment button 45 is repeated so that the density of the composite image is changed stepwise.

  Next, the operation of the color correction / black generation unit 15 that performs the composition process of the composition image with respect to the document image will be described. FIG. 3 is a flowchart showing the composition processing in the color correction / black generation unit 15 under the control of the control unit 600.

  When the copy instruction or the print instruction for the document image that is the first input image is input, the control unit 600 inputs the document image (first input image) to the color correction / black generation unit 15 ( S11), it is determined whether or not a synthesis request is input from the user (S12). This synthesis request is a request for synthesizing a synthesis image with a document image.

  The input document image is acquired by reading the document with the color image input device 200, and passes through each part before the color correction / black generation unit 15 in the color image processing apparatus 300, so that the color correction / black generation unit. 15 is an image input into the image. Alternatively, the image is input to the color image processing apparatus 300 from an external device, and is input to the color correction / black generation unit 15 through each of the preceding stages of the color correction / black generation unit 15 in the color image processing apparatus 300.

  If it is determined in S12 that a composition request has not been input, the color correction / black generation unit 15 proceeds to S16 according to an instruction from the control unit 600 and performs the subsequent processing. On the other hand, if a compositing request is input, the color correction / black generation unit 15 performs compositing processing of the compositing image with the document image in accordance with an instruction from the control unit 600.

  When performing the synthesis process, the color correction / black generation unit 15 refers to, for example, a predetermined synthesis image stored in the storage unit 19 according to a preset setting (S13). Here, each pixel of the compositing image does not have color information, but has only position information of each pixel in the compositing area of the original image. Therefore, in the processing at S13, the color correction / black generation unit 15 acquires position information of each pixel in the composition area of the composition image of the document image from the composition image.

  Next, the color correction / black generation unit 15 performs color conversion of the composition image (S14). In this process, the color correction / black generation unit 15 determines the RGB signal value of the image for synthesis by the following procedure.

  First, the RGB value of each pixel in the composition area of the composition image in the original image (hereinafter referred to as composition area RGB value) is examined. Next, the specific color signal value of the composite region RGB value is emphasized so that the same gray scale luminance value as that when the composite region RGB value is converted into the gray scale signal value is obtained. Next, the composite region RGB value determined in this way is used as the RGB value of the composite image.

  Next, the color correction / black generation unit 15 synthesizes the composition image processed in S14 with the document image to create a synthesized image (S15). This processing is generally performed in the image composition processing, and is processing for overwriting the composition image on the original image.

  Thereafter, the color correction / black generation unit 15 performs various processes on the image data (S16) and outputs the image data (S17).

  The various processes in S15 are different depending on whether the synthesis process of S13 to S15 is performed according to the request for the synthesis process or not when the synthesis process is not performed and the synthesis process of S13 to S15 is not performed.

  When the combining process is not performed, the color correction / black generation unit 15 uses the color correction table for converting the RGB signal into the CMYK signal for the original image according to the normal color correction / black generation process, and uses the RGB signal. Is converted into a CMYK signal and output to the spatial filter processing unit 16. Thereafter, the document image processed by the spatial filter processing unit 16 is processed by the output gradation correction unit 17 and the gradation reproduction processing unit 18 and stored in the storage unit 19 or a color image according to an instruction from the user. The output device 400 prints on the paper.

  On the other hand, when the synthesis process is performed, the following process is performed in addition to the above process when the synthesis process is not performed. In other words, the color correction / black generation unit 15 uses a color correction table different from the color correction table for converting RGB signals into CMYK signals, and converts the RGB signals into R′G′B suitable for scan data and filing data. 'Convert to signal. Further, the R′G′B ′ signal is stored in the storage unit 19 as filing data. The R′G′B ′ signal is output as scan data directly from the color correction / black generation unit 15 or via the storage unit 19.

  Next, a color correction / black generation unit for the read combined image, which is a read image obtained by scanning the print image obtained by printing the combined image created in the process of S15 in FIG. The process 15 will be described. FIG. 4 shows the contents of the process of the color correction / black generation unit 15 for the read combined image obtained by scanning the print image obtained by printing the combined image created in the process of S15 of FIG. It is a flowchart to show.

  When the read combined image as the second input image is input (S31), the color correction / black generation unit 15 performs color mode processing for performing color printing or color scanning in accordance with an input to the operation panel 40 from the user. It is determined whether or not it is selected (S32).

  If the color mode processing is selected as a result of the determination in S32, the color correction / black generation unit 15, the spatial filter processing unit 16, the output tone correction unit 17, and the tone reproduction processing unit 18 perform color mode processing as Normal color image processing is performed on the read combined image (second input image) (S33). The processed read composite image is output to the color image output device 400 according to a preset setting, printed, or stored in the storage unit 19.

  By performing color image processing on the read combined image, a combined image appears in the read combined image. Therefore, when a read combined image that has been subjected to color image processing is printed, the combined image is visualized (visualized) in the printed image and becomes visible.

  On the other hand, if the color mode processing is not selected in the determination of S32, it is determined whether or not the monochrome mode processing for performing monochrome printing or monochrome scanning is selected (S34).

  If the result of determination in S32 is that monochrome mode processing has not been selected, processing ends. If the monochrome mode process is selected as a result of the determination in S32, the color correction / black generation unit 15 performs a conversion process from the RGB signal to the grayscale signal on the read combined image (S35).

  The conversion process to the gray scale signal here is a process of converting the RGB signal value into a gray scale signal value by weighted averaging, or a conversion using a lookup table for converting the RGB input signal to the gray scale output signal. It is processing.

  These conversion processes to gray scale are the reverse conversion of the color conversion of the image for synthesis in S14 of FIG. Therefore, when the process of S35 is performed, the synthesis image in the read synthesized image is completely lost.

  Thereafter, the color correction / black generation unit 15, the spatial filter processing unit 16, the output gradation correction unit 17, and the gradation reproduction processing unit 18 perform normal monochrome image processing on the read combined image (S36). . The processed read composite image is output to the color image output device 400 according to a preset setting, printed, or stored in the storage unit 19.

Next, the composition processing in the color correction / black generation unit 15 will be described using a specific example.
FIG. 5 is an explanatory diagram showing an example of a synthesis process in the color correction / black generation unit 15 using a specific image. Here, a case will be described in which a synthesized image is created by synthesizing the synthesis image shown in FIG. 5B-1 with the original image shown in FIG.

  The color correction / black generation unit 15 receives an original image composed of RGB signals shown in FIG. This original image is acquired by reading the original with the color image input device 200, and is input to the color correction / black generation unit 15 through each part before the color correction / black generation unit 15 in the color image processing apparatus 300. It is an image. Alternatively, the image is input to the color image processing apparatus 300 from an external device, and is input to the color correction / black generation unit 15 through each of the preceding stages of the color correction / black generation unit 15 in the color image processing apparatus 300.

  The synthesis image shown in FIG. 5B-1 is stored and prepared in advance in the storage unit 19, for example. Each pixel of the compositing image does not have color information, but has only position information (coordinate values) of each pixel in the compositing area of the original image.

  5B-2 is color-converted from the composition image of FIG. 5B-1 by color conversion processing (S14 of FIG. 3) in the color correction / black generation unit 15. It is a thing. The color information R1, G1, and B1 values of the composition image in (b-2) of FIG. 5 are calculated with reference to the pixel values (RGB values) of the document image corresponding to the coordinate values of each pixel of the composition image. To do. Specifically, the color information R1, G1, and B1 values are calculated based on the inverse conversion of the conversion from the RGB luminance signal to the gray scale signal in the image processing when scanning the original image.

For example, when the RGB luminance signal is converted into a grayscale signal in the image processing at the time of scanning, the grayscale signal is expressed by the following conversion equation (1):
Gray = 0.3R + 0.59G + 0.11B (1)
R: R luminance signal, G: G luminance signal, B: B luminance signal, Gray: grayscale luminance signal.

Next, when R1, G1, and B1 are set so that the result after conversion to grayscale is equal to the conversion formula (1),
Gray = 0.3R1 + 0.59G1 + 0.11B1 (2)
It becomes.

Here, for example, when an image in which the G signal component is increased by 1.2 times and the R signal component is reduced by 0.8 times from the original image is created as a composition image,
G1 = 1.2G (3)
R1 = 0.8R (4)
And
The B1 signal component is calculated from equations (1), (2), (3), and (4).

That is,
B1 = (Gray-0.3R1-0.59G1) /0.11
= (0.3R + 0.59G + 0.11B-0.3R1-0.59G1) /0.11
= 0.5455R-1.0727G + B (5)
It becomes. Thereby, the color of the image for composition is determined by R1, G1, and B1 expressed by the above formulas (3), (4), and (5).

  Thereafter, the synthesized image shown in FIG. 5C is created by overwriting the original image after color conversion shown in FIG. 5B-2 on the original image shown in FIG. .

  Next, an example in which a compositing image appears or disappears due to processing on a read composited image obtained by scanning a print image of a composited image will be described. FIG. 6 is an explanatory diagram of an example in which a compositing image appears or disappears due to processing on a read composited image acquired by scanning the composited image print image illustrated in FIG.

  6A is a read combined image obtained by scanning the print image of the combined image in FIG. 5C, and FIG. 6B-1 is a diagram in FIG. This is an image obtained by performing color image processing on the read synthesized image. In the image of (b-1) in FIG. 6, since there is a color difference between the composition image and the background of the document image, the composition image can be determined. By performing predetermined color image processing on the image of (b-1) in FIG. 6, it is possible to extract the composition image in (b-2) of FIG. 6.

  On the other hand, (c-1) in FIG. 6 is an image obtained by converting the RGB signal of the read synthesized image in FIG. 6 (a) into a grayscale signal. In this image, the RGB signal of the print image is converted into a gray scale signal by the conversion equation (1) described above. In this case, as shown in the above conversion equation (5), the color value of the image for synthesis is set so that the conversion value when the RGB signal is converted into the grayscale signal is equal to the conversion value by the conversion equation (1). Set it. As a result, in the image obtained by converting the RGB signal of the read combined image into the gray scale signal ((c-1) in FIG. 6), the combining image cannot be distinguished from the document image. Therefore, as shown in (c-2) of FIG. 6, a synthesis image cannot be extracted in the monochrome image processing from the image of (c-1) of FIG. 6, and the synthesis image is completely lost. To do.

[Embodiment 2]
Another embodiment of the present invention will be described below with reference to the drawings.
In the image processing apparatus 300 according to the present embodiment, when the synthesized image is visualized by the color image processing for the read synthesized image (the image obtained by scanning the printed image of the synthesized image), the user operates the operation panel 40. By operating the composite image density adjustment button 45, the degree of visualization (visualization) of the composite image can be arbitrarily adjusted.

  FIG. 7 is an explanatory diagram of processing for adjusting the degree of visualization of the composition image in the color correction / black generation unit 15. Specifically, (a) in FIG. 7 shows a document image, (b) in FIG. 7 shows a composition image to be combined with the document image, and (c-1) in FIG. 7 shows visualization of the composition image. FIG. 7C-2 shows a read combined image after color image processing when the degree of visualization of the composite image is lowered. The finished image is shown.

  The composition of the image for composition with the document image is performed by the color correction / black generation unit 15 as in the previous embodiment. In this case, the color correction / black generation unit 15 refers to the pixel value (RGB value) of the document image corresponding to the coordinate value of each pixel of the composition image, and calculates the R1, G1, and B1 values of the composition image. To do. In the present embodiment, in the calculation of the R1, G1, and B1 values of the image for synthesis (the process of S14 in FIG. 3), the degree of visualization of the image for synthesis designated by the operation of the composite image density adjustment button 45 is set. reflect.

Specifically, the R1, G1, B1 values of the image for synthesis represented by the equations (3), (4), and (5) and the RGB value of the original document image are weighted and averaged by the coefficient α, and the degree of visualization R2, G2, and B2 values of the adjusted composite image are obtained. In this case, R2, G2, B2 values are
R2 = α * R + (1-α) * R1 (6)
G2 = α * G + (1−α) * G2 (7)
B2 = α * B + (1-α) * B2 (8) 0 ≦ α ≦ 1
It becomes.

  In the above formulas (6), (7), and (8), for example, when α = 0.5, R2, G2, and B2 use only 0.5 images for synthesis. In this case, as shown in (c-2) of FIG. 7, the composition image is difficult to be visualized.

  In the above formulas (6), (7), and (8), when α = 0, the conversion is the same as that shown in the previous embodiment, and is shown in (c-1) of FIG. Thus, the embedded image is easily visualized (visualized). Further, when α = 1, it is the same as the original image, and the composition processing of the composition image with respect to the original image is not performed.

  In the image processing apparatus 300 according to the present embodiment, as described above, the degree of visualization of the synthesized image in the synthesized image can be arbitrarily adjusted. Therefore, the synthesized image obtained by visualizing the synthesis image to a degree according to the user's preference An image can be obtained.

  Note that the composite image creation process shown in FIG. 3 and the color image process and monochrome mode process for the read composite image shown in FIG. 4 are preferably performed in the image processing apparatus 300 of the same model. This is because, in the image processing apparatus 300 of the same model, since the conversion processing algorithm and conversion table in the conversion processing to gray scale in S35 of FIG. 4 are clear, the color conversion of the image for synthesis in S14 of FIG. This is because it is easy to perform the process (inverse conversion process of the conversion process to gray scale in S35). However, even if they are not the same model, the conversion processing algorithm and conversion table used for the above gray scale conversion processing are not unique to each model of the image processing apparatus. For example, conversion using NTSC coefficients or sRGB color space is possible. Since there are many cases of L * theoretical values and general processing, the same processing is possible.

  In the above embodiment, the image processing apparatus 300 performs the process of FIG. 4 on the read combined image that is the read image of the print image of the combined image created by the process of FIG. explained. However, in the image processing apparatus 300, the synthesized image created in the process of FIG. 3 is stored in, for example, the storage unit 19, and the synthesized image is read from the storage unit 19 in the process of FIG. May be configured to perform processing. In this case, in the process of FIG. 4, as in the case described above, in the color mode process, the composite image is visualized with respect to the composited image, while in the monochrome mode process, the composite image is exposed. Processes that do not image.

  Finally, each block of the image processing apparatus 300, particularly the color correction / black generation unit 15, may be configured by hardware logic, or may be realized by software using a CPU as follows.

  That is, the image processing apparatus 300 includes a CPU (central processing unit) that executes instructions of a control program that realizes each function, a ROM (read only memory) that stores the program, and a RAM (random access memory) that expands the program. And a storage device (recording medium) such as a memory for storing the program and various data. An object of the present invention is a recording medium on which a program code (execution format program, intermediate code program, source program) of a control program of the image processing apparatus 300, which is software that realizes the above-described functions, is recorded so as to be readable by a computer. This can also be achieved by supplying the image processing apparatus 300 and reading and executing the program code recorded on the recording medium by the computer (or CPU or MPU).

  Examples of the recording medium include a tape system such as a magnetic tape and a cassette tape, a magnetic disk such as a floppy (registered trademark) disk / hard disk, and an optical disk such as a CD-ROM / MO / MD / DVD / CD-R. Card system such as IC card, IC card (including memory card) / optical card, or semiconductor memory system such as mask ROM / EPROM / EEPROM / flash ROM.

  Further, the image processing apparatus 300 may be configured to be connectable to a communication network, and the program code may be supplied via the communication network. The communication network is not particularly limited. For example, the Internet, intranet, extranet, LAN, ISDN, VAN, CATV communication network, virtual private network, telephone line network, mobile communication network, satellite communication. A net or the like is available. Further, the transmission medium constituting the communication network is not particularly limited. For example, even in the case of wired such as IEEE 1394, USB, power line carrier, cable TV line, telephone line, ADSL line, etc., infrared rays such as IrDA and remote control, Bluetooth ( (Registered trademark), 802.11 wireless, HDR, mobile phone network, satellite line, terrestrial digital network, and the like can also be used. The present invention can also be realized in the form of a computer data signal embedded in a carrier wave in which the program code is embodied by electronic transmission.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

15 Color Correction / Black Generation Unit 19 Storage Unit 40 Operation Panel 45 Composite Image Density Adjustment Button 100 Image Forming Device 200 Color Image Input Device 300 Image Processing Device 400 Color Image Output Device 600 Control Unit

Claims (5)

A synthesizing processing unit that synthesizes a synthesizing image in a synthesizing image synthesizing region of a document image, a first mode process for reproducing a color of the input image with respect to a color input image, and a first An image processing apparatus including a color conversion processing unit that performs a second mode process of converting the color of an input image by one color conversion process;
In the synthesis processing unit, the color signal value of the synthesis image is different from the color signal value of the synthesis image synthesis region, and the second mode processing is performed on the synthesized image by the color conversion processing unit. When the second color conversion process is performed, the result of the first color conversion process is that the color signal value of the image synthesis area for synthesis in the original image is equivalent to the color signal value of the image for synthesis. Performing the composition image, combining the composition image with the document image ,
The color conversion processing unit performs a process of converting a luminance signal of a color of the input image into a grayscale luminance signal in the first color conversion process,
In the second color conversion process, the synthesis processing unit obtains a grayscale luminance signal converted from a luminance signal of a color in the synthesis image synthesis area and the synthesis image as a result of the first color conversion process. The gray scale luminance signal converted from the color luminance signal is the same, and the color luminance signal of the image for synthesis is a luminance signal of a color different from the color luminance signal of the color of the synthesis image synthesis area. Performing color conversion processing on the image for synthesis;
A composite image density input unit for designating a density of the image for synthesis in the synthesized image;
The composition processing unit is configured so that the density of the composition image in the composited image when the processing in the first mode is performed is a density corresponding to an input from the composite image density input unit. An image processing apparatus for performing a third color conversion process for setting a luminance signal of a color of an image for use . A synthesis processing step of creating a composite to precomposed image synthesis image in the synthesized image combining region of the original image, the color of the input image, the processing of the first mode to reproduce the color of the input image, and in the image processing method and a color conversion processing step of performing a second mode of the process of converting the color of the input image by the first color conversion process,
In the composition processing step, when the second mode processing is performed on the composited image in the color conversion processing step, as a result of the first color conversion processing, a composition image composition in the document image is performed. Performing a second color conversion process in which the color signal value of the region and the color signal value of the synthesis image are equivalent to the synthesis image, and synthesizing the synthesis image with the document image ;
The color conversion processing step performs a process of converting a luminance signal of the color of the input image into a grayscale luminance signal in the first color conversion process,
In the second color conversion process, the synthesis process step includes a step of converting the grayscale luminance signal converted from the luminance signal of the color in the synthesis image synthesis area and the synthesis image as a result of the first color conversion process. The gray scale luminance signal converted from the color luminance signal is the same, and the color luminance signal of the image for synthesis is a luminance signal of a color different from the color luminance signal of the color of the synthesis image synthesis area. Performing color conversion processing on the image for synthesis;
In the synthesis processing step, the density of the image for synthesis in the synthesized image when the processing in the first mode is performed is a density according to an input specifying the density of the image for synthesis in the synthesized image. As described above, the third color conversion processing for setting the luminance signal of the color of the image for synthesis is performed . An image forming apparatus comprising: the image processing apparatus according to claim 1; an image reading apparatus that reads an original image; and a printing apparatus that prints an image processed by the image processing apparatus. A program for causing a computer to function as a composition processing unit and a color conversion processing unit of the image processing apparatus according to claim 1 . The computer-readable recording medium which recorded the program of Claim 4 .