JP3738810B2 - Image printing method and apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image printing method and apparatus, and more particularly, to an image printing method and apparatus for converting a color image signal into a single color image signal and obtaining a single color print output based on the converted single color image signal. Is.
[0002]
[Prior art]
In recent years, image data can be easily created using a wide variety of image capturing devices due to the low price of scanners and the advent of digital cameras. In addition, along with the development and widespread use of office processing equipment, photographic images have been added to manuscripts such as word-processing documents, which have traditionally consisted solely of characters, tables, line drawings, etc., simply expressed in black and white (binary) only. It is also possible to fit. Further, in gravure and the like, a halftone original is often used as a printed original.
[0003]
As described above, in recent years, instead of a manuscript that is simply represented only in black and white, a variety of information is to be conveyed in one manuscript, and therefore, black and white characters and tables represented mainly by binary values. , Line drawings, and silver halide photographs that can represent halftones, and halftone images (not limited to only photographic parts) are intricately mixed, and the composition of the originals used for printing is becoming increasingly complex. The trend of aging has been followed.
[0004]
When a black-and-white print image is formed in a copier, printer, stencil printing machine, etc., a document containing characters, photographs, halftone dots, etc. is usually read using a monochrome scanner, and the pixels in the main scanning direction and the sub-scanning direction are read. A multi-tone image signal carrying monochrome image information sampled in units is obtained, and the multi-tone image signal is binarized and printed using black ink on white paper based on the binarized image data. Need to do. Needless to say, if another color ink is used instead of the black ink, a print output of that color (single color) can be obtained.
[0005]
Here, when binarizing a multi-tone image signal, a simple binarization method in which binarization is generally performed based on a single threshold is generally used for a document composed of characters or diagrams. A binarization method such as a pseudo halftone expression method is used for an original document that is composed of photographs having a halftone. Typical examples of the pseudo halftone expression method include a dither method and an error diffusion method.
[0006]
The simple binarization method for binarization based on the single threshold value is configured by scanning a multi-tone image signal in the main and sub-scan directions, respectively, and using the multi-tone image signal based on a preset threshold value. This is a method of binarizing each pixel. In the dither method, a dither matrix is created by varying the threshold value in a certain pattern, the multi-tone image signal of the dither matrix is scanned in the main and sub-scanning directions, and the pixel density is binarized based on each threshold value. Thus, the pseudo gradation expression is applied to the recording paper. The error diffusion method scans a multi-tone image signal in the main and sub-scanning directions, propagates a binarization error generated in pixels around the pixel of interest to the pixel of interest at a preset ratio, and repositions the pixel of interest This is a method of performing pseudo gradation expression on the recording paper by binarizing the image signal.
[0007]
The simple binarization method has an effect of gathering black pixels in a portion where the change in the density gradient is abrupt, and is therefore an effective method for images such as characters and line drawings where contrast should be emphasized. For an image having a smooth change in density gradient such as a photograph and having a low contrast, image information having a smooth change in density gradient is damaged, so that it is not suitable for binarization of an image signal such as a photograph.
[0008]
On the other hand, the binarization method using the pseudo halftone processing by the dither method or the error diffusion method gives a quasi-smooth expression in an area where the change in the density gradient is small, and the contrast of a photograph or the like is reduced. This is an effective technique for weak images, but it is originally black pixels in character portions and the like in images with strong contrast that require concentration of black pixels in portions where the density gradient changes abruptly, such as characters and line drawings. This is not suitable for binarization of image signals of characters and the like because a hollow white pixel is generated at a power portion, the sharpness of the character is lowered, and the shape of the thin character is lost.
[0009]
Therefore, as described above, if it is intended to obtain a printed matter of a black-and-white document in which characters, photos, halftone dots, etc. are mixed, the binarization processing of the image signal obtained by reading is composed of documents, tables, line drawings, etc. The binarized area (hereinafter referred to as character area) is binarized by a simple binarization method, and can represent a halftone such as a photographic area or a halftone dot area (hereinafter referred to as a halftone area). It is preferable to perform binarization using the dither method or error diffusion method (collectively halftone area). As described above, in order to print various mixed documents neatly, it is equivalent to one document. A processing technique for accurately discriminating a character area and a halftone area from the read image signal for one frame and performing an optimum binarization process for each area is required. In addition, silver halide photographs and halftone dot originals have the problem that moire is likely to occur if the halftone image is binarized, such as halftone processing. It is not desirable to simply perform the same binarization processing for both photographs. From this point as well, the character, photograph, and halftone areas are accurately determined from the read document information, and the document image area is determined. It is necessary to perform an optimal binarization process according to the type.
[0010]
In the stencil printing apparatus, since the dot gain is large, the image is likely to be crushed, and if the same binarization processing is performed, the entire image is printed and output as a darker image than a normal printer. For example, if the halftone area is binarized simply by the error diffusion method or the like, a beautiful image cannot be reproduced. Therefore, not only the area determination of the original but also the binarization processing according to the output device type is necessary.
[0011]
On the other hand, as is well known, not only black and white photographic images but also color photographic images can be inserted, and color halftone originals are also used as printing originals in gravure and the like and are used for printing. The proportion of color in the manuscript that is being used is higher than that in black and white.
[0012]
Here, when a black and white print image is formed using a color original, a multi-tone representing only lightness (density) information in the color image corresponding to the black and white image information by reading the color original using a monochrome scanner. By obtaining an image signal, binarizing the multi-gradation image signal to obtain binarized data, and performing printing based on the binarized data, the same as in the case of using a conventional black and white document, Can be obtained.
[0013]
However, in such a simple method, only lightness information in a color image is used, and information on hue and saturation cannot be effectively used for area discrimination or binarization. Is recognized as a character and printed appropriately, but a thin red character is not determined as a character but as a photograph and is printed as a drowned character. In this case, it may be possible to adjust the gain of the multi-tone image signal or the parameters for region discrimination and binarization to obtain a more appropriate print output. However, other areas cannot be adjusted so that appropriate print output can be obtained for all areas.
[0014]
In addition, there is a method of detecting only specific color information using a color conversion filter on a monochrome scanner and performing color classification using expression such as shading, but it is weak and effective. It is enough to know the type of
[0015]
On the other hand, a color original is read using a color scanner, and color image signals (multi-tone image signals) for each color carrying, for example, each color information of R (red), G (green), and B (blue). ) And a color image signal is converted into one monochrome image signal (multi-tone image signal) X representing monochrome (monochrome) image information using a known conversion formula of X = 0.3R + 0.6G + 0.1B. A method of performing region discrimination and binarization using the converted monochrome image signal X is also conceivable.
[0016]
[Problems to be solved by the invention]
However, even with this method, it cannot be said that color information such as lightness, hue, and saturation in a color image is sufficiently utilized for area discrimination and binarization, depending on the area type and color type. It cannot be said that proper area discrimination or binarization processing is performed, and it is not always easy to output color characters or the like at a desired density on black and white printing.
[0017]
For example, in the case of a manuscript in which red and black characters are mixed, the same character result is obtained for both black and red characters. When printing only in a single color (for example, black), the colored character is gray (black and white). When the above processing is performed, it is difficult to obtain a print output in which the red characters that are desired to be noticed in the manuscript cannot be emphasized because they are integrated with other black characters and cannot be emphasized. Similarly, in a photograph, it is difficult to emphasize (weakly) a character or image of any color in the photograph area, for example, by emphasizing the red apple red.
[0018]
As described above, when trying to perform single color printing using a color original, the conventional printing method cannot fully utilize the color information of the color original, and cannot provide a variety of printed expressions.
[0019]
SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a printing method and apparatus that makes it possible to produce a variety of printed expressions by utilizing color information in a color document and preventing color characters from becoming blurred. It is intended to provide.
[0020]
[Means for Solving the Problems]
The first image printing method according to the present invention determines, for each color, each pixel of color image information expressed by a large number of pixels, which is a character area or a halftone area, and carries color image information The color image signal to be distributed to either the character region component or the halftone region component so as to correspond to the determined pixel region for each color, and the color image signal for each allocated region Is converted into a monochromatic image signal, and the binarized signal corresponding to the determined pixel region is applied to the converted monochromatic image signal, and the binarized signal binarized by the binarizing process Based on the above, a monochrome print output is obtained.
[0021]
The second image printing method according to the present invention determines whether each pixel of color image information represented by a large number of pixels is a character area or a halftone area, and carries a color image information. The signal is distributed to either the character region component or the halftone region component so as to correspond to the determined pixel region for each color, and the hue of the color image signal for each of the allocated regions , Controlling at least one of lightness and saturation to obtain an edited color image signal, converting the edited color image signal into a single color image signal, and determining the discrimination for the converted single color image signal. A binarization process corresponding to the pixel area is performed, and a monochrome print output is obtained based on the binarized signal binarized by the binarization process.
[0022]
In the second image printing method, at least one of the selection and combination of signals of a desired color component among the color image signals and the strength of the signal of the color component obtained by the selection or the combination is obtained. It is desirable to carry out the control to obtain an edited color image signal.
[0023]
Further, in the printing method combining the first method and the second method, that is, in the first method, the region is determined for each color, and the color image signal is obtained for each color as described above. After the allocation to the components of each region, the edited color image signal can be obtained by controlling at least one of the hue, brightness, and saturation of the color image signal for each allocated component. desirable.
[0024]
In the above, “color image signal” means a set of image signals each carrying each color component in the color image information. For example, R (red), G (green), and B (blue) components, respectively. Is a set of R signal, G signal, B signal and the like. At this time, as each color component, it is preferable to use a color component having a complementary color relationship with the ink used in the color original. For example, ink of each color of Y (yellow), M (magenta), and C (cyan) is used. If R is used, the above R, G and B components may be used.
[0025]
The “halftone area” means an area that can represent a halftone, such as a silver halide photograph area or a halftone dot area, as described above.
[0026]
“Perform binarization processing corresponding to the determined pixel region” means that when it is determined that the pixel to be processed is a pixel in the character region, the binarization processing for the character region is performed and the pixel in the photographic region This means that the binarization process for the photographic area is performed when it is determined that the pixel is, and the binarization process for the dot area is performed when it is determined that the pixel is the dot area pixel. In particular, in the first method, it means that binarization processing corresponding to each region is performed based on the result determined for each color as described above.
[0027]
“Acquiring a monochromatic print output” means that a print image is obtained by printing using one color ink as an ink. For example, monochrome (monochrome) printing that prints on white paper using black ink It is not limited to.
[0028]
In the second method, “selection” means selecting any one signal from signals of each color component, and is processing corresponding to color extraction (one aspect of hue control), If the R signal, G signal, and B signal are used as signals corresponding to the R, G, and B components, it is to select (extract) one signal of the R signal, the G signal, or the B signal. . “Combination” means that a plurality of (not limited to two) signals are selected from each signal, and the selected signals are combined to generate a signal representing a new color component. This is one mode of control. In this case, the synthesized signal includes a signal representing a monochrome achromatic component. For example, in the above example, the R signal and the G signal are combined to generate a Y (yellow) signal, the G signal and the B signal are combined to generate a C (cyan) signal, and the B signal and the R signal are combined. Are combined to generate an M (magenta) signal, and an R signal, a G signal, and a B signal are combined to generate a BW (monochrome) signal. By this “selection” and “combination”, signals of components of seven colors of R, G, B, Y, C, M, and BW can be obtained for each region in the previous period.
[0029]
“The strength of the color component signal obtained by selection or combination” means, for example, that the level of the signal of the seven color components obtained as described above is increased or decreased. It is one mode of control. In this case, the process of setting the level to zero is a process of deleting the color component.
[0030]
A first image printing apparatus according to the present invention is an apparatus for realizing the first image printing method, wherein each pixel of color image information expressed by a large number of pixels is any pixel in a character area and a halftone area. An area discriminating means for discriminating each color, and a color image signal carrying color image information, either a character area component or a halftone area component so as to correspond to the discriminated pixel area for each color. An image area separating means for distributing the image, a converting means for converting a color image signal into a monochrome image signal for each of the allocated areas, and a pixel area determined for the converted monochrome image signal. A binarizing unit that performs a corresponding binarization process and a printing unit that obtains a monochromatic print output based on the binarized signal binarized by the binarization process It is.
[0031]
A second image printing apparatus according to the present invention is an apparatus for realizing the second image printing method, wherein each pixel of color image information expressed by a large number of pixels is any pixel in a character area and a halftone area. An area discriminating unit for discriminating whether or not a color image signal carrying color image information is allocated to either a character area component or a halftone area component so as to correspond to the discriminated pixel area for each color. Distributed image area separating means, and for each allocated area, control means for controlling at least one of hue, brightness and saturation of the color image signal to obtain an edited color image signal; Conversion means for converting the edited color image signal into a monochrome image signal for each area, and binarization means for performing binarization processing corresponding to the determined pixel area on the converted monochrome image signal And the binarization process Based on the binarized binary signal it is characterized in that a printing means for obtaining a print output of a single color.
[0032]
The control means of the second image printing apparatus selects at least one of the selection and combination of signals of a desired color component among the color image signals and the intensity of the signal of the color component obtained by the selection or the combination. It is desirable to perform the control by performing one.
[0033]
Further, in the first apparatus combined with the second apparatus, that is, in the first apparatus, for each component distributed by the image area separation means, the hue, brightness, and saturation of the color image signal. A control means for obtaining an edited color image signal by controlling at least one, and a conversion means for converting the edited color image signal into a monochromatic image signal for each separated component; It is desirable to do.
[0034]
【The invention's effect】
According to the first image printing method and apparatus of the present invention, it is determined for each color whether each pixel of the color image information is a character area or a halftone area, and the converted single-color image signal is detected. The binarization process corresponding to the determined pixel area is performed, in other words, the binarization process corresponding to the color type is performed for each area. This makes it possible to utilize the color information of a color document, and can produce a variety of printed expressions that are richer than before. For example, in monochromatic (for example, black and white) printing, emphasis is made so as not to blur color characters. Or print with a different density from a black character or the like.
[0035]
According to the second image printing method and apparatus of the present invention, it is determined whether each pixel of the color image information is a character area or a halftone area, and is distributed so as to correspond to the determined area. For each of the components, at least one of the hue, brightness, and saturation of the color image signal is subjected to color editing (control), and then the monochrome image signal obtained by converting the edited color image signal A binarization process corresponding to the determined pixel area is performed, in other words, a binarization process corresponding to each area is performed using a signal after color editing for each area. Therefore, it is possible to reflect the result of color-specific processing (color editing result) as a change in density (shading) in the printed image, and as a result, it is possible to utilize the color information of the color document. The first method and As with the location, so that it is printed representation rich in variety.
[0036]
In color editing, any editing (control) method may be used as long as it controls at least one of hue, brightness, and saturation. If a method of selecting and combining color components and performing at least one of the strengths and weaknesses of the color components obtained by these is used, the color editing operation can be performed very easily.
[0037]
Furthermore, in the image printing method and apparatus according to the present invention, a color image signal is distributed to each area, and color editing and binarization processing corresponding to each area is performed for each allocated area. Therefore, even if processing is performed so that one of the areas has a desired density, there is no possibility that the other areas will be inappropriate, and a print output having a desired density can be obtained for all areas. Can be.
[0038]
As described above, according to the image printing method and apparatus according to the present invention, color editing can be performed so that a desired print output can be obtained for each region type and each color type according to the document type. It is possible to provide a method and an apparatus for performing monochromatic plate making and printing by expression.
[0039]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing a configuration of an image printing apparatus according to an embodiment of the present invention.
[0040]
As shown in FIG. 1, the image printing apparatus 1 includes a color scanner 11 that separates and reads a color original (image information) S into color information of three colors R (red), G (green), and B (blue). And an image input means 10 having RGB color space image signals (hereinafter referred to as RGB data) carrying the R, G, and B components input from the image input means 10. , Data G, and data R) for each color of R, G, and B, each pixel of the color document S read by the color scanner 11 is a character area or a halftone area. The area determination means 20 for determination and the RGB data are divided into character area components and halftone areas so as to correspond to the pixel areas determined by the area determination means 20 for each color, that is, for each of the data R, data G, and data B. Any of the ingredients An image area separating means 30 for separating (distributing) the image data, and a color editing means for obtaining edited RGB data by controlling at least one of the hue, brightness and saturation of the RGB data for each separated area ( (Corresponding to the control means according to the present invention) 40, the conversion means 50 for converting the edited RGB data for each area into monochrome data as monochrome image data, and the area determination means 20 for the converted monochrome data. Printing is performed using a single color (for example, black) ink based on the binarized data binarized by the binarization processing, and binarization means 70 for performing binarization processing corresponding to the pixel area. And printing means 80.
[0041]
The image input means 10 includes a color distribution means 12 as means for converting the dot sequential RGB data read by the color scanner 11 into the synchronized data R, data G, and data B for one color original S. , R component memory 13R, G component memory 13G, and B component memory 13B are provided for storing data R, data G, and data B, respectively, input in a dot sequential manner.
[0042]
The image printing apparatus 1 having the above configuration corresponds to a photographic area and a halftone dot area as halftone areas. The data R output from the R component memory 13R corresponding to the R, G, and B is determined so that it can be determined for each color of the R, G, and B that the pixel is in the point area. R component discrimination means 21R to be used, G component discrimination means 21G to use data G output from the G component memory 13G, and B component discrimination means 21B to use data B output from the B component memory 13B are provided. .
[0043]
The image area separation means 30 receives the data R, data G, and data B output from the component memories 13R, 13G, and 13B for each data of the pixels determined by the area determination means 21R, 21G, and 21B. R component image area separation means 31R for separating data R into each area, data G as means for separating and allocating the character area component, photo area component, and halftone area component so as to correspond to the area Is provided with a G component image area separating means 31G for separating the data B into each area, and a B component image area separating means 31B for separating the data B into each area.
[0044]
The image area separating means 30 includes an R character memory 32R for storing the character area component data RM separated by the R component image area separating means 31R, an R photo memory 33R for storing the photo area component data RS, and a network. R halftone dot memory 34R for storing point area component data RA, G character memory 32G for storing character area component data GM separated by G component image area separating means 31G, and G for storing photographic area component data GS Photo memory 33G, G halftone dot memory 34G for storing halftone dot area component data GA, B character memory 32B for storing character area component data BM separated by B component image area separation means 31B, photographic area component data A B photo memory 33B for storing BS and a B halftone memory 34B for storing halftone area component data BA are provided.
[0045]
The color editing means 40 controls the edited data RM ′, GM ′, BM ′ by controlling at least one of hue, brightness, and saturation for each of the separated character region component data RM, GM, BM. Is provided for character component color editing means 41M to obtain the edited data RS ′, GS ′, BS ′ by performing the same control as described above for the data RS, GS, BS of the separated photographic region components. The color editing means 41S and the halftone dot color editing means 41A for obtaining the edited data RA ′, GA ′, BA ′ by performing the same control as described above on the separated halftone area component data RA, GA, BA. Is provided.
[0046]
The conversion means 50 converts the edited data RM ′, GM ′, BM ′ of the character area component into monochrome data XM as means for converting each edited data into monochrome data for each separated area. Conversion means 51M for converting, conversion means 51S for converting the edited data RS ′, GS ′, BS ′ for the photographic area component into monochrome data XS, and edited data RA ′, GA ′, for the halftone area component Conversion means 51A for converting BA ′ into monochrome data XA is provided.
[0047]
The binarization means 70 performs binarization processing corresponding to the pixel areas determined by the area determination means 21R, 21G, and 21B on the converted monochrome data XM, XS, and XA for each area component. The binarizing means 71M, 71S, 71A are provided corresponding to the respective areas.
[0048]
For example, as the binarizing means 71M for the character region component, not only the so-called simple binarization process suitable for the black character but also the color character is forcibly changed to the black character so that the color character can be emphasized. It is assumed that various binarization processes such as a binarization process to be performed, a binarization process to make a shaded character, or a binarization process using an error diffusion process can be freely selected.
[0049]
Also, the binarizing means 70 is provided with a combining means 72 for combining the binarized result for each component with the binarized data for one original.
[0050]
Next, the operation of the image printing apparatus 1 having the above configuration will be described in detail.
[0051]
First, the color original S is read by the color scanner 11 of the image input unit 10, and the color original S is decomposed into color information of three colors R, G, and B, and the resolution (generally high resolution) in the color scanner 11 is obtained. An image signal that has been sampled and quantized based on the obtained signal is obtained and converted into digital data D by an A / D converter (not shown). This data D is first converted into R component-only data R by the color distribution means 12 and stored in the R component memory 13R. Next, it is converted into data G having only the G component and stored in the G component memory 13G, and further converted into B data having only the B component and stored in the B component memory 13B.
[0052]
The data R, G, and B stored in the component memories 13R, 13G, and 13B are read into the corresponding area discriminating means 21R, 21G, and 21B, and each pixel is in any of the character area, the photographic area, and the halftone area. Whether each pixel is a pixel is determined for each color.
[0053]
As the area discrimination processing used here, character discrimination processing that uses abrupt density difference information from the surroundings, and halftone dot pattern information that appears periodically, which are generally used in conventional monochrome processing, are used. Any discrimination processing such as halftone dot discrimination processing may be used. Also, the discrimination results for the discrimination target pixels by the area discrimination means 21R, 21G, and 21B are all the same. This is because the color document S normally uses Y, M, and C inks, and the image printing apparatus 1 uses R, G, and B component signals that are complementary to the colors of these inks as color image signals. Since it is used, it is considered that any original image has not a few R, G, and B components, and the regularity of the dot pattern does not change. This is because it may be considered that there is not. When signals of color components not having a complementary color relationship are used as described above, processing such as correcting the discrimination result of each component is performed accordingly (detailed description of correction processing is omitted here). .
[0054]
Further, the data R stored in the R component memory 13R is input to the R component image area separating means 31R, and the character area component data RM, so as to correspond to the pixel area determined by the R component determining means 21R. The image area component data RM and the halftone dot area component data RA are separated, and the character area component data RM is stored in the R character memory 32R. Similarly, the photographic area component data RS is stored in the R photo memory 33R. The halftone dot region component data RA is stored in the R halftone dot memory 34R.
[0055]
The data G stored in the G component memory 13G is input to the G component image area separating means 31G and separated into the data GM, GS, GA of each area component as described above, and the data GM of the character area component is G Similarly, the photographic area component data GS is stored in the G photographic memory 33G and the halftone dot area component data GA is stored in the G halftone memory 34G.
[0056]
The image data B stored in the B component memory 13B is input to the B component image area separating means 31B and separated into the data BM, BS, BA of each area component as described above, and the data BM of the character area component is Similarly, the photographic area component data BS is stored in the B photographic memory 33B, and the halftone dot area component data BA is stored in the B halftone dot memory 34B.
[0057]
With the above processing, the RGB data for one color original S is separated into character, photo, and halftone areas for each of the R, G, and B color components, and as a result, the image area is separated into a total of nine types of components. Is done. The above-mentioned data are all high-resolution data, and the nine types of high-resolution image data are generated based on the color original S.
[0058]
Next, the color editing unit 40 adjusts the hue, brightness, and saturation. Note that the color editing means 40 is input with information related to color editing (color adjustment) from the operator or information designating pre-programmed color editing processing. These pieces of information include information regarding the color, strength, deletion, hue conversion, and the like that are desired to be edited. Specifically, the following processing is performed.
[0059]
First, the character component color editing means 41M receives each data of the character region component, that is, data RM stored in the R character memory 32R, data GM stored in the G character memory 32G, and data BM stored in the B character memory 32B. The read data RM, GM, and BM are read, and at least one of hue, brightness, and saturation is controlled to obtain edited data RM ′, GM ′, and BM ′. Specifically, character data of seven colors of R, G, B, C, M, Y, and WB can be arbitrarily created from selection and combination of each data RM, GM, and BM. For example, the data GM and BM of only the character part obtained by separating the G component and the B component in the image area are extracted, and the character data of the C component is obtained by extracting a common part from the extraction result, and R, G, When data RM, GM, and BM of only the character portion obtained by separating all the components of B from the image area are extracted, character data of the black component is obtained. Further, the color editing of the data in the character area can be freely performed by increasing / decreasing the level of the character data of these seven colors.
[0060]
The edited data RM ′, GM ′, and BM ′ for the character region component are input to the conversion means 51M, and the monochrome data XM using the general conversion formula XM = 0.3RM ′ + 0.6GM ′ + 0.1BM ′. Is converted to Needless to say, other conversion formulas may be used. The converted monochrome data XM is input to the binarizing means 71M, and binarization processing corresponding to the pixel area determined by the area determining means 21R, 21G, 21B (in this case, of course, binarization corresponding to the character area). Processing) and converted into binary data DM. As the binarization process corresponding to the character area, a simple binarization process is used as usual in the case of a black character, and in the case of a color character, a binarization process in which the color character is forced to be a black character. A binarization process for converting into halftone characters or a binarization process using an error diffusion process is used.
[0061]
Similarly, the photographic component color editing means 41S is used for each data of photographic area components, that is, data RS stored in the R photographic memory 33R, data GS stored in the G photographic memory 33G, and data BS stored in the B photographic memory 33B. , And for each data RS, GS, BS, at least one of hue, brightness, and saturation is controlled to obtain edited data RS ′, GS ′, BS ′. Specifically, seven-color photo data of R, G, B, C, M, Y, and WB can be arbitrarily created from selection and combination of each data RS, GS, and BS. Furthermore, the color of the data in the photographic area can be freely edited by increasing / decreasing the level of the seven colors of photographic data.
[0062]
The edited data RS ′, GS ′, BS ′ for the photographic region component is input to the conversion unit 51S, converted into monochrome data XS in the same manner as the character region component, and then input to the binarization unit 71S. A binarization process (in this case, a binarization process corresponding to a photographic area) corresponding to the pixel area determined by the determination means 21R, 21G, and 21B is performed and converted into binary data DS. Here, as the binarization processing corresponding to the photographic region, error diffusion processing, dither processing, and the like can be freely selected and performed.
[0063]
Similarly, the halftone dot component color editing means 41A stores the halftone dot area component data, that is, the data RA stored in the R halftone dot memory 34R, the data GA stored in the G halftone dot memory 34G, and the B halftone dot memory 34B. The stored data BA is read out, and edited data RA ′, GA ′, BA ′ is obtained by controlling at least one of hue, brightness, and saturation for each data RA, GA, BA. Specifically, halftone dot data of R, G, B, C, M, Y, and WB can be arbitrarily created from selection and combination of the data RA, GA, and BA. For example, when only the halftone dot data GA and RA obtained by separating the G component and the R component in the image area are extracted, and a common portion is extracted from the extraction result, Y dot halftone data is obtained. Furthermore, the color editing of the data in the halftone dot area can be freely performed by increasing or decreasing the level of the halftone dot data.
[0064]
The edited data RA ′, GA ′, BA ′ for the halftone dot area component is input to the conversion means 51S, converted to monochrome data XA in the same manner as the character area component, and then input to the binarization means 71A. A binarization process (in this case, a binarization process corresponding to a halftone dot area) corresponding to the pixel area determined by the area determination means 21R, 21G, and 21B is performed and converted into binary data DA. As the binarization processing corresponding to the halftone dot region here, a halftone processing is performed by performing a general smoothing process or the like as a countermeasure against moire of a halftone original.
[0065]
As described above, the binarized data DM, DS, DA binarized for each area is input to the combining means 72 and combined with the binarized data D0 for one color document S. That is, the binarized data DM, DS, and DA are pasted together to obtain binarized data D0 for one color original S in which characters, photos, and halftone dots are integrated.
[0066]
The binarized data D0 is input to the printing unit 80, and printing is performed using single color ink based on the binarized data D0.
[0067]
According to the image printing apparatus 1 having the above-described configuration, the components of the seven colors R, G, B, Y, C, M, and BW are set for each region by the “selection” and “combination” of the colors as described above. Since the signal is obtained, as a result, the three areas of characters, photos, and halftone dots are classified according to seven kinds of colors, and 3 × 7 = 21 color-specific area data can be created. By increasing or decreasing the level, it is possible to control hue, lightness, and saturation, and by converting this result into single-color image data and printing, various density representations are possible, and a wide variety of printing is possible. It becomes possible.
[0068]
For example, the density is weaker than black characters so that it does not become a drowned character, or the characters are forcibly made black characters, or the difference is expressed by shading, or the error diffusion processing is performed to express the difference for each color or density By doing so, the red character of the original can be emphasized. Even if the red character portion of the document is determined not as a character region but as a photographic region, if the color is edited so that red is emphasized, the density can be set so as not to be a blurred character. Furthermore, when the level of the data RS is increased, the red component of the apple in the photographic area can be emphasized. Of course, the same applies to other color components.
[0069]
As described above in detail, according to the image printing method and apparatus according to the present invention, each color document is read using the R, G, and B component signals obtained by reading the color document with a color scanner. It is determined for each color component whether the pixel is a pixel in a character portion, a photographic portion, or a halftone dot portion, and each signal of R, G, B is converted into a character, a photo, Seven colors of R, G, B, C, M, Y, and WB are obtained by separating into three areas of halftone dots and arbitrarily selecting and combining the R, G, and B signals for each of the separated areas. The image signal can be separated (divided) into a total of 21 areas of 3 areas. As a result, the color type and the original type (character, photograph, halftone dot) are freely selected and then converted into a single color signal. By applying binarization processing corresponding to each, the color image signal is converted into Than when printing is performed using the net in signal converted into a monochromatic signal, it can be seen that it is more various density representation.
[0070]
In the above-described embodiment, the region determination is performed for each color component. However, if there is a substantially complementary color relationship between the color component of the printing ink and the color component of the image signal, as described above. Since the discrimination results of the respective color components are substantially the same, it is not always necessary to perform the area discrimination for each color component. For example, a single color signal is obtained using the signals R, G, and B output from the memories 13R, 113G, and 13B. Alternatively, the region determination may be performed collectively using the single color signal.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of an image printing apparatus according to the present invention.
[Explanation of symbols]
1 Image printing device
10 Image input section
20 area discrimination means
30 Image area separation means
40 color editing means
50 Conversion means
70 Binarization means
80 printing means

Claims (2)

It is determined for each color component representing each color of the color image information whether each pixel of the color image information represented by a large number of pixels is a character area or a halftone area.
Distributing the color image signal carrying the color image information to either the character region component or the halftone region component so as to correspond to the determined pixel region for each color component ,
For each of the allocated regions, an edited color image signal is obtained by independently controlling at least one level of the signal of each color component and the signal generated by the combination of the signal of each color component,
The edited color image signal obtained for each region is converted into a monochrome image signal,
A binarization process corresponding to the determined pixel area is performed on the converted monochrome image signal,
An image printing method characterized in that a monochrome print output is obtained based on a binarized signal binarized by the binarization processing. Area discriminating means for discriminating for each color component representing each color of the color image information whether each pixel of the color image information represented by a large number of pixels is a character area or a halftone area;
An image that distributes the color image signal carrying the color image information to either the character region component or the halftone region component so as to correspond to the determined pixel region for each color component. Area separation means;
Control means for independently controlling at least one level of the signal of each color component and the signal generated by the signal combination of each color component to obtain an edited color image signal for each allocated area;
Conversion means for converting the edited color image signal obtained for each respective region in monochromatic image signal,
Binarizing means for performing binarization processing corresponding to the determined pixel area on the converted monochrome image signal;
An image printing apparatus comprising: a printing unit that obtains a monochromatic print output based on a binarized signal binarized by the binarization process.

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