JPH1011568A - Picture processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve picture segmenting processing ability by executing a picture emphasizing processing only with respect to pictures obtained by the segmenting, composing magnification and reduction of the picture and the modifying processing of a color tone and gradation. SOLUTION: After the modifying processing of the color tone and gradation and the variable power processing such as the segmenting/composing and magnifying/reducing of the picture, the picture emphasizing processing is executed. A picture emphasizing means 150 consists of a contrast emphasizing device 152 and a picture sharpening device 154. In this case the means 152 can be used as the device 154 to adjust each density value of a high (brightest part) and a shadow (dark part) called set points to emphasize the contrast of the picture to reproduce a more natural picture by printing. In addition, the device 154 can be utilized by a differential filter signal superimposing device 156 and secondary differential data of the picture is prepared by a second filter to superimpose to gradation data of an original picture to obtain a sharper picture.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cutting out a part of an image composed of digital image data, combining it with another image, performing scaling processing such as enlargement and reduction of an image, and adjusting the color tone and gradation. The present invention relates to an image processing method for performing a retouching process and creating plate making data for printing, and more particularly to an image processing method using an image enhancement process in order to improve the quality of a target image.

[0002]

2. Description of the Related Art In recent years, in the plate making process in the production of printed materials such as catalogs and pamphlets using photographs as manuscripts, it has been necessary to reduce the labor required for image retouching and to combine and edit images, images and figures, or images and characters. To automate,
2. Description of the Related Art A plate making / editing system using an image processing device including a large-capacity image data storage device and a computer such as a personal computer and a workstation is widely used.

The plate making / editing system includes an image input system called a color scanner for taking a color image such as a photograph and an illustration into an image data storage device, and a color image data input to the image data storage device. An image editing system that lays out images on a page-by-page basis along with text, headings, graphs, and tables, as well as retouching, and becomes an original plate for producing printing plates of images, characters, and figures laid out on a page-by-page basis. An image output system for drawing and outputting on a plate making film.

In the above-mentioned image input system, after setting geometric conditions such as enlargement / reduction ratio, rotation angle, and trimming of an image, a photograph of a color positive film is optically scanned to obtain RGB (red, green, blue) RGB. RGB data converted to digital data while being separated into primary colors, and further converted to digital data
Color image data is converted to YMCK (yellow, red, indigo,
(Sumi) Color conversion into color image data.

In the image editing system, characters and graphics are laid out on a computer screen together with a color image, and the combined image data is input to an image output system, and a halftone positive image for four colors of YMCK is provided. Alternatively, the mesh negative image is exposed and drawn on a plate making film.

Further, in the image editing system, partial image modification called retouching, coloring of figures and characters called color fill, modification of color tone and gradation of the entire image, modification of image and modification of magnification, Trimming, synthesizing a plurality of images, and the like may be performed, and special effects called posterization, solarization, filtering, and the like may be applied to the images.

On the other hand, in the image output system, first, the gradation data of the input edited color image is converted into Y, M by an image data converter called a Raster Image Processor (RIP). ,
It is converted into a dot image composed of dots for each of the C and K print colors.

The character data is converted into a dot image by referring to character shape data called a font.
The graphic data is also converted to a dot image as a line drawing, and the Y,
It is combined with each halftone image composed of M, C, and K dots.

Next, for each of Y, M, C, and K printing colors,
An image output device called an image setter individually scans and exposes a halftone dot image in which an image, a character, and a graphic are combined, to create an original for four colors laid out in page units.

In the printing of color images such as photographs and illustrations, the image quality is degraded by the influence of the spectral absorption characteristics and viscosity of the printing ink, the whiteness of the paper and the ink adhesion characteristics, the printing plate type and the printing pressure. In the plate making / editing system, the color tone and gradation are adjusted in advance to improve the color, volume, and texture of the image, and to perform an image enhancement process for enhancing the detail of the image.

For example, yellow (Yell) used in printing
ow: yellow Y), magenta (magenta: red M), and cyan (Cyan: indigo C) inks have spectral absorptions which are considerably deviated from ideal characteristics due to reasons such as printability, weather resistance and economy. It is a characteristic, in order to balance the color and density according to the unnecessary absorption components of each ink,
In the plate making process, the color tone and gradation are adjusted by color masking.

In color masking, in order to faithfully reproduce the colors of an original image by printing, the three primary colors Y, M, and C for printing, and R (Red) and G (color separation) for color separation of a color image. For each color component (Green: green) and B (Blue: blue), the density is finely adjusted to adjust the color tone.

Further, in order to compensate for the insufficient density of shadows (dark areas) when the Y, M, and C inks are overprinted, to enhance the contrast of the image, and to perform neutral (achromatic) correction, (Black: K, Bk, or BL
A color image is printed with four colors of ink to which ink has been added.

The image data for black ink is represented by R, G,
When generating from the B, Y, M, and C color components, the color image material can be created using a method such as skeleton black that focuses only on the shadow part or full black that handles the entire image regardless of the density of the image. By adjusting the applied density range of the black plate accordingly, the density and color of an image that is difficult to reproduce with only the three primary color inks of Y, M, and C are compensated.

When the density of an image is modified by using the above-described black ink, the amount of ink in a portion where yellow, magenta, and cyan are overprinted is reduced in advance, and the corresponding amount is replaced with UCR (under-color). remova
l: under color removal) is performed.

On the other hand, there is a limit to the color and density of the reproduced image depending on the paper, printing ink, and printing method. In order to express a color image in the limited color and density range, the color of the original image is determined in advance. And a method of printing by partially compressing the density.

However, simply compressing the colors and densities of the original image over the entire image significantly reduces the quality of the printed image. The reproducibility of the color and density of an image is improved by individually adjusting the density of the lightest part, light part (light part), middle part, and shadow (dark part) for each color component.

Further, in order to improve the image quality and sharpness of the image due to printing conditions such as printing ink and printing pressure, an image enhancement process called sharpness for enhancing image details is performed.

Enhancing the sharpness has the effect of sharpening the image. For example, it is possible to emphasize the metallic feeling of a metallic material, and it is also possible to make a blurred image without sharpness apparently clear. it can.

Conversely, in the case of an image of a watercolor material such as a Japanese painting, the sharpness may be reduced to emphasize the blur of the image quality.

As described above, in the plate making process for printing a color image, in order to faithfully reproduce the original image, color masking for adjusting colors and densities according to the suitability of printing ink, paper, and a printing press. In addition, a sharpness process for adjusting a color tone and a gradation and sharpening an image is indispensable so as not to impair the texture of the material.

The above-described color masking and sharpness processing have been conventionally performed by various methods, and in the past, a photographic optical method using a masking film or a transparent positive or negative film having gradation, Recently, processing is performed by a method using a dedicated image processing apparatus called a “color scanner” or a “color computer”.

On the other hand, in commercial printed materials such as catalogs and pamphlets, and published printed materials such as magazines and books, various print materials such as photographs, illustrations, figures, and characters are combined in a large number to form books and leaflets. , Individual materials, point by point, color
Adjusting the color tone, gradation, and image quality of an image by masking and sharpness processing requires a great deal of trouble.

Further, in commercial prints and publication prints,
When laying out a combination of various materials, there are many cases where text is pasted into a part of a photo, or multiple photos are combined or superimposed and combined. It is necessary to perform the process individually for each of the Y, M, C, and K color plates corresponding to the printing colors.

With the development of computer-based image processing technology, the above-described pasting of characters and synthesis of photographs and illustrations can be gradually reduced in labor and automated, resulting in a "layout scanner" or "total scanner". A plate making / editing system for image editing and retouching for printing, called "printing", has been developed, and the plate making process in printing has been digitized.

FIG. 7 is a block diagram schematically showing a configuration of a plate making / editing system called a layout scanner or a total scanner used in the above plate making process.

As shown in the figure, the plate making / editing system
Image input device 210 that optically scans a color image such as a photograph or an illustration and converts it into an electric signal, and converts it into digital data.
And digitized image data into YMCK for printing.
An image input system 200 composed of an input image processing device 220 that converts data into data and further adjusts the color tone, gradation, and image quality of the image, and image data storage that stores image data input by the image input system 200 Device 320
And an image editing system 300 comprising an image data processing device 310 for performing image data modification processing, editing processing, and output processing, and a YMCK plate making film for printing plate production based on the image data subjected to layout editing. And an image output system 400 for producing the same.

The image input device 210 of the image input system 200 is a scanning drive control unit 212 for optically scanning a photographic color positive film, and converts the optically scanned color image into three primary colors of RGB and converts them into electric signals. It is composed of an RGB photoelectric conversion unit 214 and an A / D conversion unit that converts the density signal of the image converted into the RGB electric signal into digital data.

A color image signal separated into three primary colors of RGB and converted into digital data is input to an input image processing unit 22.
The RGB signal is converted to a YMCK signal for printing by the YMCK data conversion unit 222 of 0.

Next, the color image data of YMCK is
Color tone adjustment unit 224, gradation adjustment unit 226, image quality adjustment unit 22
At 8, adjust the color tone, gradation, and image quality for printing,
The modified Y, M, C, and K color images are input to the image data storage device 320 of the image editing system 300.

[0031] Y input to the image editing system 300,
The M, C, and K image data are stored in the image data processing device 310.
The modification processing unit 312 modifies a partial color tone and gradation of an input image, and further modifies images, characters, illustrations,
The image is enlarged or reduced to a predetermined size based on layout information such as a figure, and further, an image is cut out and synthesized into a predetermined shape and size based on the layout information.

As described above, when a character is pasted on a part of a photograph, or a plurality of photographs are combined or superimposed to form a composite photograph, the photograph is cut out into the shape of characters or the shape of the subject of the photograph. First, make a cutting mask,
Next, the target image and the background image are cut out into predetermined shapes.

Further, the cut out images, characters, figures,
To the illustration, the layout position of each material is assigned by the edit processing unit 314, and the layout data of the print format is compiled in page units.

The layout data aggregated in page units is as follows:
For example, the image data is created in a page description language called “postscript”, and in the output processing unit 316, image data of a photograph or an illustration is converted into Y,
The image data is output to the image output system 400 for each of the M, C, and K color plates.

The image output system 400 converts Y, M, C, and K image data into a raster image conversion unit 402 called a RIP based on layout data in a page description language created by the editing processing system 300.
, The image data is sequentially converted into halftone image data composed of dots, and is temporarily recorded in the image memory 408.

Next, based on the halftone image data read from the image memory 408, the halftone image is exposed and drawn by the image drawing mechanism constituted by the scanning drive control unit 404 and the light-to-light conversion unit 406.

Each of the Y, M, C, and K plate making films produced by the image output system 400 is subjected to a development process, and then subjected to a photosensitive resin plate or a PS plate by a plate device (not shown). Then, Y, M, C, and K printing plates are manufactured by contact exposure to a printing plate such as a printing plate, and a color image is printed using the printing plates for the four colors developed and fixed.

When the image is cut out in the editing and plate making system as described above, a cutout mask can be easily created when the cutout is simply cut into a square or a circle. However, as in the case of cutting out a complicated shape, for example, a person image. Since it is necessary to separate each hair from the background image, it is not easy to create such a cutout mask.

On the other hand, when a photograph or illustration to be cut out is input by the image input system 200, sharpness processing for enhancing the detail of the image and improving the sharpness of the image is performed in advance. In cutting out or combining images in the image editing system 300, image quality may be degraded due to the influence of the sharpness processing.

For example, in an image having a large change in density, a false outline may be generated in the details of the image due to the sharpness processing, and the image is cut out at a position different from the original outline due to the influence of the false outline. There is.

Further, when an image subjected to sharpness processing is cut out along a contour line and combined with another image, the color and density near the contour line are clearly different from the color and density of the combined background image. Appears, unnaturalness remains in the synthesized image, and the image tends to be uncomfortable.

On the other hand, when an image is cut out while avoiding the false contour line and synthesized with another image, the seam portion of the synthesized image has a visual unnaturalness because the effect of the sharpness processing has been removed. Cheap.

Conversely, if the image to be cut out is cut out and synthesized without being subjected to the sharpness processing, a printed matter in which the sharpness of the image is significantly reduced is obtained.

[0044]

The image processing apparatus in the above-described plate making / editing system includes a color masking and a black plate signal generation for improving the print quality of the image, a sharpness processing for improving the sharpness of the image, and the like. Is processed simultaneously by an image processing apparatus of an image input system when a photograph is converted into image data by an image input apparatus called a color scanner.

For this reason, when the image editing system performs an image cutting process, the target image has already been subjected to the sharpness processing, so that a false contour line is generated or the color or density near the contour line is reduced. In some cases, there is a large change due to the influence of the background image of the original image.

For example, a contour line emphasized in the original image can be enhanced by looking at the original image as it is. Looks natural.

This is because the background color of the original image along the contour line is mixed with the inner edge of the cut image by performing the sharpness processing. If this cut image is combined with another background image, This is because the color and density of the outline portion do not match the color tone of the synthesized background image and remain as an unnatural color.

Therefore, when cutting out a part of the original image, care must be taken to cut out the inside of the outline of the target image.

In the composite image obtained by cutting out the inside of the outline and synthesizing it with another image, the inside of the cut out image is subjected to sharpness processing, but the outline portion of the cut out image has a sharpness effect removed. Therefore, the image looks unnatural.

Further, an image which has been subjected to sharpness processing prior to the clipping process may have a color tone or gradation area that was not present in the original image, thereby causing a false contour line and making the clipping process difficult. Sometimes.

Further, in the same manner as in the above-described case of cutting out and synthesizing the image, the correction processing section of the image editing system applies the image to which the sharpness processing has been performed in advance.
When scaling processing such as enlargement or reduction of an image is performed, inconveniences such as contour lines being emphasized more than necessary, and conversely, the effect of the sharpness processing are reduced.

Further, when the image subjected to the sharpness processing is subjected to the color tone and gradation correction processing, the contour line portion of the image often becomes unnatural color or density.

On the other hand, in order to avoid the above-mentioned inconveniences, an image to be subjected to extraction processing, an image to be subjected to scaling such as enlargement or reduction, or an image to be subjected to color tone or gradation modification processing. On the other hand, plate making without sharpness processing
When editing and printing the image, the printed image becomes a blurred image with unclear outlines.

Therefore, according to the present invention, in an image processing apparatus of a plate making / editing system used in a production process of a printed matter, cutting, synthesis, enlargement, reduction, or color tone of a photograph or the like is performed.
The purpose is to obtain an image with clear details even when performing image processing such as gradation adjustment, and in particular, image processing to obtain a printed matter without deteriorating the quality of the original image and having no unnaturalness The task is to obtain a method.

[0055]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides an image processing apparatus which performs image processing prior to image extraction processing, image scaling processing, or color tone or gradation adjustment processing. Prevents image quality degradation by performing image enhancement processing only on images obtained by cropping, combining, enlarging, reducing, or modifying color and gradation without performing enhancement processing. As a result, the above-mentioned problem was solved, and furthermore, the image processing ability was improved.

That is, the present invention provides an image extracting means for extracting a part of an image, an image synthesizing means for synthesizing the extracted image with another image, a scaling means for enlarging or reducing the image, or a color tone of the image. In an image processing apparatus comprising a tone gradation modifying means for modifying gradation and an image enhancing means for enhancing image quality of an image, the image cutout means, the image synthesizing means, the scaling means, or the tone gradation modifying means This is an image processing method for obtaining a clear image without impairing the quality of the original image by emphasizing the image quality of the image processed by the image processing means by the image enhancement means.

[0057]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An image processing method according to the present invention is an image processing method in a plate making / editing system for producing a printed matter as shown in FIG. In an image processing apparatus provided with a scaling unit, a tone adjusting unit, and an image quality enhancing unit, an image is cut out, combined, enlarged, reduced, or after adjusting the tone or the tone of the image, This is an image processing method for performing image quality enhancement processing for enhancing image quality.

That is, according to the image processing method of the present invention, an image input device called a plate making color scanner or simply a scanner for inputting a photograph such as a color film as digital image data to an image editing system. An image input system composed of an input image processing device for converting digital image data into image data for printing; an image editing system for correcting, editing, and outputting input image data; and an image editing system for printing. This is an image processing method used in a plate making / editing system including an image output system that outputs image data to a plate making film.

In the above-described image input system, the photographic film attached to the transparent cylindrical drum is illuminated by the plate-making color scanner, and the transmitted light is received by the photoelectric conversion element to be converted into digital image data. The color tone and gradation are adjusted by the image processing device, and image data for black plate is generated.

That is, when a photograph or illustration is a color image, the image is separated into three primary colors through an RGB color filter by an image input device, and the light intensity of each color is received by an optical sensor. The image data is converted into digital data by a / D (analog / digital) converter to obtain an RGB color image signal.

Then, the RGB color image signals are converted into yellow (Yellow: yellow Y), magenta (magenta: red M), and cyan (Cyan:
The color image signals are converted into color image signals of four primary colors, i.e., blue (C) and black (black: black K). During this time, logarithmic compression, color tone adjustment, gradation adjustment, sharpness processing, logarithmic expansion, and the like are performed.

In the plate making color scanner, sharpness processing for sharpening an image is generally performed by the following method.

First, an image of a color photograph is photoelectrically converted through a main aperture to obtain a high-resolution RGB color image signal and a USM (unsharp mask).
Through a large aperture, referred to as a low-resolution image signal, referred to as an unsharp mask signal.

Next, a difference signal between the high-resolution color image signal and the low-resolution image density signal is obtained, and the high-resolution color image signal and the difference signal are added again to obtain a color photographic image. Has improved sharpness.

Conventionally, the image was emphasized by the sharpness processing means in the input image processing device of the above plate making color scanner. However, as described above, the image data processing device of the image editing system cuts out and synthesizes the image. In the present invention, the image enhancement processing is not performed at this stage because the image quality is not excellent when the enlargement, reduction, or color tone or gradation adjustment processing is performed.

Next, the image data converted into the YMCK color image signal is input to an image data storage device of an image editing system, and the image data processing device of the image editing system is used to deteriorate image quality of a photograph. , Remove dust, remove flaws, retouch, or modify colors, gradations, etc., and then scale, rotate, crop, crop, Perform editing processing such as composition.

That is, according to the present invention, in the above-described image data processing device of the image editing system, the image emphasizing process is performed after the color tone or gradation modifying process, the image cropping process, or the scaling process such as enlargement / reduction. By doing so, unnatural image enhancement due to sharpness processing, which was a problem in the prior art, is eliminated.Also, poor extraction due to the influence of false contour lines at the time of extraction processing is eliminated, and stable extraction processing is performed. Is now possible.

Here, an image processing apparatus used in the image processing method of the present invention will be described with reference to FIG. FIG.
1 is a configuration block diagram showing an embodiment of an image processing apparatus for performing an image processing method of the present invention.

As shown in the figure, the image processing apparatus 100
Image data storage means 160 and image data storage means 16
Image reading means 110 for reading out the image data stored in 0 and cutting out the image into a predetermined shape; an image synthesizing means 120 for synthesizing the cut out image with another image; and a scaling means for enlarging or reducing the image. 130, a tone gradation adjusting means 140 for adjusting the color tone and gradation of the image, and the details of the image are enhanced with respect to the image data processed by the cutout, synthesis, scaling, and tone gradation adjusting means. And image enhancement means 150.

The image processing device 100 is connected to an image input device 200 for inputting image data to the image data storage means 160 and an image output device 400 for outputting image processed image data. It is also possible to input and output image data for image cutout processing, synthesis processing, scaling processing such as enlargement / reduction, and color tone correction processing.

The image processing apparatus 100 according to the present invention comprises the above-described image extracting means 110, image synthesizing means 120, scaling means 1
30, color tone gradation adjusting means 140, and image enhancing means 15
0, the details of which are described below.

First, an embodiment of the image extracting means 110 in the image processing apparatus 100 of the present invention will be described with reference to the drawings. FIG. 2 shows an image processing apparatus 1 according to an embodiment of the present invention.
FIG. 2 is a block diagram showing a configuration of an image extracting unit 110 constituting the image 00.

As shown in FIG. 2, the image extracting means 110 for separating the image of the designated area of the color image data input via the image input device 200 from the background image includes at least a contour extracting device 112 and a cutting device. And an output mask making device 114.

The contour extracting device 112 is a means for extracting a contour line of the target image when there is no clear difference in the color tone and gradation, or the color and density of the background image as compared with the image to be cut out. .

For example, by extracting the difference signal between the USM (unsharp mask) signal data and the original image data in the above-described sharpness processing, that is, the zero cross point of the detail signal,
Contour lines can be easily extracted.

Next, in order to mask the image data of the non-cut image portion outside the contour of the cut image extracted by the contour extracting device 112, for example, the pixel in the area surrounded by the contour is set to “1”. Then, the extraction mask creating device 114 creates extraction mask data for setting the pixel of the other area to be masked to “0”.

By multiplying (or AND processing) the pixel value of the above-mentioned cut-out mask data with the pixel value of the original image data, all the pixel values of the non-cut-out image portion become “0” and are included in the original image. The extracted image to be extracted is left as it is, and the image is extracted.

Here, the image cutout processing by the image cutout means 110 will be described with reference to the drawings. FIG. 4 shows a typical image data example for explaining the principle of the image cutout processing according to the present invention.

FIG. 4A is a digital signal of a scanning signal of an original image taken out from the main aperture of the image input device, and shows an image composed of two shades of color for convenience.

In the figure, “9” represents a pixel having a low image density, and “18” represents a pixel having a high image density.

FIG. 4 (a) shows the density distribution of an image composed of 10 pixels in each of the vertical and horizontal directions by numerical values. In the center, a cross-shaped high-density portion (shown as "18" in the figure) is shown. The figure shows the image data composed of a low density portion (in the figure, denoted by “9”).

In the figure, in order to separate the cross-shaped high-density portion at the center from the low-density portion which is the background image, for example, a histogram of the density distribution is obtained, and the valley of the distribution curve is cut out to obtain the cut-out image density. And a pixel that is equal to or larger than the threshold value and a pixel that is smaller than the threshold value are selected to create a binary extraction mask in which one is set to “0” and the other is set to “1”.

By multiplying (or AND processing) the pixel value of the binarized clipping mask with the pixel value of the original image, the required clipping target image shown in FIG. Can be cut out from

Further, by multiplying (or AND processing) the mask obtained by inverting the pixel values of the above-described binary extraction mask and the background image to be synthesized, a background image conforming to the shape of the subject image can be obtained. By adding the background image and the image cut out from the original image, separate images can be combined into one image.

As a method for creating an image cutout mask, there are two other methods in addition to the above. The first is a method called a density mask or an auto mask, in which a background image of an image to be cut out is composed of an opposite color, and
This is effective when the gradation change is small, and by setting a specific density range for the background image, it is possible to create a cutout mask by extracting the corresponding pixels within the set density range.

Second, there is a method called tracing. In tracing, a contour mask of the clipped image is traced by a light pen or a mouse cursor displayed on the image display device, and the contour of the clipped image is converted into data to create a clipping mask.

In the first method, a clipping mask can be created by a simple operation as compared with the second method. However, when the subject to be clipped is photographed, the image is clipped. It is necessary to set the background of the color and density assuming that

If the target image is to be cut out from a photograph such as a landscape where there is no room to select the color and density of the background image without assuming the cutout of the image, the cutout is performed by the second method called tracing. Create an outgoing mask.

The tracing method will be described in more detail. In tracing, first, for example, a secondary differentiation process called Laplacian is performed on the original image data to extract a contour line of the image to be extracted.

FIG. 4D shows an example of a Laplacian of 3 × 3 pixels, and shows a weighting coefficient for a target pixel and its eight neighboring pixels. In the figure, the weight of the target pixel is set to “8”. , By setting the weight of the eight neighboring pixels around it to “−1”, a second-order differential filter is formed.

Using the weighting factors shown in FIG.
FIG. 4 (c) shows the result of the second derivative processing of the original image data of FIG. In the result of the differential processing shown in FIG. 4C, a portion where the pixel value changes from positive to negative or from negative to positive, that is, a zero-crossing (zero-crossing) portion is an outline of the image.

Next, by instructing all pixels inside the zero-cross portion to be “1” and all pixels outside the zero-cross portion to be “0” by using a light pen or a mouse cursor, FIG. The cut-out mask data as shown in FIG.

In this embodiment, each pixel value of the extraction mask of FIG. 4E is multiplied (or AND-processed) by the pixel value of the original image of FIG. Can be obtained.

Next, the image synthesizing means 120 in the image processing apparatus of the present invention will be described. For example, when the two images are partially overlapped and combined, the extraction target image of the first image is first extracted into the shape of the extraction mask using the above-described extraction mask, and then the extraction mask is used. By inverting the pixel value of “1” to “0” and “0” to “1”, multiplying (or AND processing) the cutout mask of the inverted pixel value and the second image, A clipped image of the second image in which the pixel values corresponding to the clipped image portion of the first image are all “0” can be obtained.

Next, by adding the cut-out image of the first image and the cut-out image of the second image, the first image and the second image are combined with each other without any gaps or overlaps. Can be synthesized.

Further, the pixel value of the above-mentioned cut-out mask is multi-valued, and the gradation data of each of the two images is multiplied by a fixed ratio with the pixel value of the multi-valued cut-out mask. It is also possible to create a composite image in which two images overlap.

Next, the scaling means 130 in the image processing method of the present invention will be described. Magnification processing such as enlargement or reduction of an image converts image data of a certain number of pixels into image data of a larger or smaller number of pixels. While moving the pixels of the original image to the coordinates corresponding to the enlargement ratio, the pixel values of the insufficient pixels that occur with the enlargement are calculated as follows:
Calculation is performed based on the pixel values of the adjacent original image, and an enlarged image in which the number of pixels is increased by complementing the insufficient pixels is created.

On the other hand, in the case of reducing the image, when pixels are moved to the coordinates corresponding to the reduction ratio, some of the pixels of the original image are decimated in accordance with the reduction ratio to create a reduced image with a reduced number of pixels. I do.

Next, the color tone gradation adjusting means 140 in the image processing method of the present invention will be described. The adjustment of the color tone and the gradation is performed by changing the pixel values of the pixels constituting the image to the pixel values of the target color tone and the gradation, respectively. For example, C, M, Y, K, or R, G, The color tone of the image can be adjusted by increasing or decreasing the pixel value of the target color among the color components of B at a fixed ratio, and increasing or decreasing the pixel value at the same ratio for all colors. Can adjust the image density.

As described in detail above, the image processing method according to the present invention includes image extracting means for extracting a part of an image, image synthesizing means for synthesizing the extracted image with another image, and enlarging and reducing the image. In an image processing apparatus provided with a magnification changing means for adjusting the color tone and the gradation of the image, the image is processed by the image cutting means, the image synthesizing means, the scaling means or the color tone gradation adjusting means. The image processing apparatus according to the present invention includes an image enhancing unit for enhancing the image quality of the image obtained by the image processing.

FIG. 3 is a block diagram showing the structure of the image enhancing means 150 constituting the image processing apparatus 100 according to the embodiment of the present invention.

As shown in FIG. 3, the image enhancing means 150 comprises, for example, a contrast enhancing device 152 and an image quality sharpening device 154.
4 comprises a differential filter signal superimposer 156 and an unsharp mask signal superimposer 158.

The image processing apparatus 100 in the image processing method of the present invention uses three types of image enhancing means: a contrast enhancing device 152, a differential filter signal superimposing device 156, and an unsharp mask signal superimposing device 154. However, here, the unsharp mask signal superposition unit 154
Will be described with reference to the drawings.

FIG. 5 shows a schematic example of image data for explaining an example of the image enhancement processing in the present invention.

FIG. 5A is a digital signal of a scanning signal of an original image taken out from the main aperture of the image input device, similarly to FIG. 4A. FIG.

In the figure, “9” represents a pixel having a low image density, and “18” represents a pixel having a high image density.

FIG. 5 (a) shows the density distribution of an image composed of 10 pixels in each of the vertical and horizontal directions by numerical values. In the center, a cross-shaped high-density portion (shown as "18" in the figure) is shown. The figure shows the image data composed of a low density portion (in the figure, denoted by “9”).

FIG. 5B shows image data called a USM (unsharp mask) signal. USM
The signal is generated based on the original image data of FIG. 5A. For example, in the case of FIG. 5B, the signal is calculated based on the simple average value of the gradation data of 3 × 3 pixels of the original image.

In this embodiment, for convenience of explanation, 3 × of the original image is used.
Although the USM signal is generated by a simple average value of the gradation data of three pixels, 5 × 5 pixels, 7 ×
The USM signal may be generated based on seven or more pixels. Instead of the simple average value of the target pixel, a weighted average value, median value, or mode value can be used as the USM signal.

The USM signal obtained by the simple average of 3 × 3 pixels is an image signal in which the details of the original image are blurred, and the USM signal, that is, the blurred image data is subtracted from the original image data. The detail signal of the original image as shown in FIG. 5 (c) can be extracted. Further, by adding the detail signal to the original image, image data in which the detail is enhanced as shown in FIG. 5D can be obtained.

When comparing the image data in which the details of FIG. 5D are emphasized with the original image data of FIG. 5A,
FIG. 5D shows a cross-shaped image with a higher density in the center,
It can be seen that the density change near the boundary with the surrounding background image with low density is emphasized.

Note that, in FIG.
When the detail signal obtained by subtracting the SM signal data is added to the original image data, the degree of detail enhancement can be changed by increasing or decreasing the magnitude of the detail signal. In addition, by inverting the polarity of the detail signal and adding the original signal to the original image data, the sharpness of the image can be reduced and the blurring can be emphasized.

As described above, sharp and clear image quality is obtained by detail enhancement using the USM signal, and the above-described series of image enhancement processing is performed by software of a computer used in an image processing apparatus. Can be easily realized.

Further, in the image processing method of the present invention, a contrast enhancing device 152 can be used as the image enhancing means 150, and each density value of a highlight (lightest portion) and a shadow (dark portion) called a set point is adjusted. As a result, the contrast of the image can be enhanced, and a more natural image can be reproduced by printing.

Further, according to the image processing method of the present invention, the differential filter signal superposition
The image quality sharpening device 154 according to 56 can be used, and the second derivative data of the image is created by a two-dimensional filter called Laplacian, for example, as in the case of the outline extracting device 112 in the image extracting means 110 described above. By superimposing on the gradation data of the image, a clearer image can be obtained.

Next, a process for producing a printed material using the image processing method of the present invention will be described. FIG. 6 is a flowchart for explaining a process of producing a printed material by the image processing method of the present invention.

In the figure, a step 1 is an allocation process, in which a correct arrangement is performed by using a digitizer (not shown) based on rough sketches of photographs, illustrations, texts, title characters, etc. constituting a printed matter. And convert it to numerical data. Next, based on the numerical data, that is, the layout data, a layout diagram of a material such as a photograph is created on layout paper using a plotter.

On the other hand, the allocation data is stored in the image input system 20 constituting the plate making / editing system shown in FIG.
0, image editing system 300, image output system 40
0 is input via a floppy disk or a communication line, respectively, and is set as an image processing condition of each image processing system.

For example, in the case of a color image such as a photograph or an illustration, the layout data includes a trimming dimension, an enlargement or reduction ratio, a rotation angle for correcting the image inclination, a halftone frequency at printing, and a color separation at color separation. Scanning line density.

The trimming size of the image, the enlargement or reduction magnification, the inclination or rotation angle of the image, and the scanning line density at the time of color separation accompanying the enlargement or reduction of the image are represented by the magnification,
Using an angle measuring device (not shown) or the like, measurement is performed based on the assignment instruction, and the measurement result is set in a plate-making color scanner that is an image input device.

Next, in step 2, the color image such as a photograph is separated into RGB by the image input system 200, converted into digital data, and input to the plate making / editing system. The image input process of step 2 is a process performed by the image input device 210 of the image input system 200.

In the image input process of step 2, a photograph or illustration is optically read by an image input device (called a color scanner or simply a scanner in the printing process), converted into digital image data, and stored in the image data storage device 320. Remember.

In the image input in the plate making / editing system, based on the trimming dimension of the image, the rotation angle for correcting the inclination, the enlargement / reduction magnification, and the scanning line density at the time of reading the image, which are set in the allocating process of step 1 described above. The operation conditions of the image input device 210 are set, and a photograph or illustration (usually a color positive film) is optically scanned with transmitted light and converted into an electric signal.

The image input step of step 2 is basically a step of separating a color image into three primary colors of RGB and converting a density signal of the obtained image into digital data which can be handled by a computer. is there.

The RGB image data converted into digital data is then subjected to the YMCK
To image data. The image processing in step 3 is normally performed by the input image processing device 220 attached to the image input system 200. Generally, the image processing in step 2 is performed by an image input system called a color scanner. Executed concurrently with disassembly.

In step 3, the color tone and gradation correction amount were adjusted based on the color and density characteristics of the image obtained by simply measuring the positive film of the color photograph in advance, and the print reproducibility of the image was improved. A YMCK color image signal is obtained.

That is, when converting an RGB image signal into YMCK printing image data, color tone characteristics and gradation characteristics suitable for printing are added, and defects in the color and density of the original image are adapted to the printing characteristics. To fix.

For example, generation of black plate data K for compensating for image density deficiency, removal of each undercolor of Y, M, and C accompanying generation of black plate data K, and furthermore, the spectral characteristics of YMCK printing ink For example, color tone adjustment by color masking to adjust the color balance. Further, in order to correct the bias of the density of the original image and to improve the sharpness of the detail of the image, the characteristics of the respective densities of the highlight, light, intermediate portion and dark portion are corrected.

The color tone and gradation adjustment in step 3 are uniformly applied to the entire area of the original image. Therefore, if a plurality of original images are simultaneously scanned and input in the image input processing in step 2 described above. Creates YMCK image data in which the color tone and gradation are adjusted under the same conditions for all the original images.

Next, the YMCK image data created in step 3 is temporarily recorded in the image data storage device 320 of the image editing system 300 for the modification processing in step 4. The modification processing in step 4 is performed by the image data processing device 31 of the image editing system 300.
This is a process performed by the modification processing unit 312 provided for 0.

In the modification processing in step 4, the color, density, image size, and the like of the YMCK image data input to the image data storage device 320 through steps 2 and 3 are finely adjusted image by image. At the same time, for individual color images, such as individual or partial color tone and gradation adjustments, dirt, dust, scratches, etc., and unnecessary background removal that could not be processed in the image processing step of step 3 above. This is the process of retouching, repairing, and processing.

The image retouching processing in step 4 described above is roughly classified into the following three steps. First, dirt, dust, and scratches on the original image are repaired, and the color of the skin and teeth of the human image, the sky, the sea, and the mountains are removed. There are image repair processing for correcting colors and partially adjusting color tone, gradation, and texture, and second, geometric image correction processing such as magnification adjustment such as enlargement and reduction of images and rotation.

Third, the subject portion of the modified image is cut out along the outer contour, the background image is erased, and the image is synthesized with another image. There is a special effect process that deforms the image and deforms the color tone and gradation.

Fifthly, based on the allocation data, a cutout mask for synthesizing a character or a figure with an image is created based on the original image, and the color tone of the figure and the density or halftone dot percentage are designated. Then, there is a graphic processing for coloring a graphic called "shade-off" or "painting".

Next, when the output material of the image, the character, and the graphic is completed by the retouching processing of the step 4, the process proceeds to the editing processing step of the step 5. The editing process in step 5 is a process performed by the editing processing unit 314 provided in the image data processing device 310 of the image editing system 300.

The editing process of step 5 is a process of collecting image data according to the layout data for each unit page and adjusting the appearance of the printing paper. In step 5, first, the image data is cut out to a predetermined shape and dimensions based on the allocation data, and if there is a cutout mask, the image is cut out according to the shape of the mask. To record.

Next, for the character and text data, the pattern data of the corresponding character is read from the character pattern storage device, converted into image data, and recorded in the image data storage device 320 as image data colored in a predetermined color. You. Similarly, the graphic image is also imaged and recorded on the image data storage device 320 in which the image data is arranged.

The photographs, illustrations, characters, graphics, and data collected in the image data storage device 320 as described above are simply laid out for each unit page.
For example, the seam between the two combined images may be so noticeable that the seam can be made inconspicuous by performing image processing such as averaging around the seam of the images.

In the image processing method of the present invention, image quality is sharpened by the USM (unsharp mask) signal superimposing device or the differential filter signal superimposing device, or the image is processed by the contrast emphasizing device. Apply emphasis processing.

In the above image data storage device, the image data in page units laid out and subjected to image enhancement processing is
Next, in the image output process of step 6, each original film for a printing plate is drawn on the plate making film and corresponds to YMCK four color printing inks.

The image output process in step 6 is a process performed by the image output system 400 of the plate making / editing system. In the image output process of step 6, each image data of YMCK of the image data storage device 320 is output to the image output system 400 for each color, and the image output system 400 sends the image data to the raster image conversion unit 402 based on the gradation data of the image. To generate a halftone image having a predetermined number of lines.

In the image output system 400, usually,
The halftone image expressed by the number of lines of 3 to 10 lines / mm is converted to 50 to 200 dots / mm by the raster image converter.
, Ie, one halftone dot image is expressed by
The image is converted into a dot image composed of hundreds of dots and drawn on a plate making film.

That is, in the gradation data of an image in the image data storage device, one color is usually represented by 8 bits, and the density of the image is represented by 256 gradations. The system 400 converts the size of the halftone image into halftone image data and generates halftone image data such as a photograph.

When plate making films for four colors of Y, M, C, and K are output by an image output system, for example, a photosensitive printing plate (PS) used in lithographic offset printing is used.
If the version is negative, the negative halftone dot image is drawn and output. When the photosensitive printing plate is a positive type, a positive halftone dot image is drawn and output.

The plate-making film drawn by color separation is used as an exposure film for preparing a printing plate in the printing plate process of step 7, and is aligned with a photosensitive printing plate and brought into close contact therewith. Irradiating the printing plate with a halftone image of the light transmitting portion by irradiating an exposure light beam from the substrate to form a latent image. Next, the latent image formed on the photosensitive layer of the printing plate is developed to prepare a printing plate for lithographic offset.

Finally, in step 8, using the printing plate and YMCK printing ink corresponding to the printing plate,
For example, a printed matter is produced by an offset printing machine.

[0147] The obtained printed matter is subjected to the editing processing in step 5 by collecting, in the editing processing in step 5, an image that has been cut out, combined, enlarged, reduced, or modified in tone and gradation. And a contrast enhancement device or the like for the image,
Since image enhancement processing was performed using an image sharpening device such as a differential filter signal superimposing device or an unsharp mask signal superimposing device, it was possible to obtain a printed matter with sharp image detail and sharpness.

[0148]

As described in detail above, the image processing method of the present invention provides an image extracting means for extracting a part of an image, an image synthesizing means for synthesizing the extracted image with another image, and enlarging the image. An image processing apparatus comprising: a scaling unit for reducing the size or a tone / tone adjusting unit for adjusting the color tone and the tone of the image; and an image enhancing unit for enhancing the image quality of the image. The image processed by the means, the scaling means, or the color tone correction means is enhanced by the image enhancement means to give an unnatural impression without losing the details of the original image. There is an effect that a clearer printed matter can be obtained.

Further, according to the image processing method of the present invention, unnecessary contour lines which hinder the automatic clipping process do not occur in the clipping process of the image, the clipping process can be stabilized, and the clipping of the target image can be performed. A mask can be automatically created, and a clipped image and another background image can be easily combined.

Furthermore, the unnaturalness of the seam of the composite image can be eliminated, and a clear image with clear details can be obtained.

[Brief description of the drawings]

FIG. 1 is a configuration block diagram of an image processing apparatus.

FIG. 2 is a block diagram illustrating a configuration of an image cutting unit of the image processing apparatus.

FIG. 3 is a configuration block diagram of an image enhancement unit of the image processing apparatus.

FIG. 4 is an example of image data for explaining the principle of image cutout processing.

FIG. 5 is an example of image data for explaining the principle of image enhancement processing.

FIG. 6 is an image processing step diagram of a printed material.

FIG. 7 is a block diagram of an apparatus configuration of a plate making / editing system.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 Image processing device 110 Image extraction means 112 Contour extraction device 114 Extraction mask creation device 120 Image synthesis means 130 Magnification means 140 Color tone gradation adjustment means 150 Image enhancement means 152 Contrast enhancement device 154 Image sharpening device 156 Differential filter signal Superimposer 158 Unsharp mask signal superimposer 160 Image data storage means 200 Image input system 210 Image input device 212 Scan drive controller 214 RGB photoelectric converter 216 Analog / digital converter 220 Input image processor 222 YMCK data converter 224 Color tone Adjustment unit 226 Gradation adjustment unit 228 Image quality adjustment unit 300 Image editing system 310 Image data processing device 312 Modification processing unit 314 Editing processing unit 316 Output processing unit 320 Image data storage device 400 Image output System 402 raster image converting unit 404 scan driving unit 406 optic converter section 408 image memory

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location H04N 1/60 H04N 1/40 D 1/46 1/46 Z

Claims (1)

[Claims] 1. An image extracting means for extracting a part of an image, an image synthesizing means for synthesizing the extracted image with another image, a scaling means for enlarging or reducing the image, or a color tone and gradation of the image. An image processing apparatus comprising a color tone gradation modifying means for modifying and an image enhancing means for enhancing the image quality of an image, wherein the image is processed by the image cutout means, the image synthesizing means, the scaling means, or the color tone gradation modifying means. An image processing method characterized in that the image quality of the image is enhanced by an image enhancing means.