JP2000149010A - Image processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image processor which can easily produce a pictorial image that is drawn by a user's desired touch from an original, such as a photographic image or a digital camera image. SOLUTION: A 1st threshold matrix production means 1 produces a threshold matrix from a 1st monochromatic gradation image (touch image) by deciding the threshold which corresponds to the density value for every pixel. Then a binarization means 2 compares the density value of a 2nd monochromatic gradation image with the threshold of the threshold matrix for each of pixels corresponding to each other and binarizes the 2nd monochromatic gray image, based on the result of the comparison.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing apparatus, and more particularly, to an image processing apparatus capable of generating a pictorial image drawn by a user's desired touch using a photographic image or a digital camera image as a document. It concerns the device.

[0002]

2. Description of the Related Art Hitherto, various methods have been proposed for processing a digital image obtained from a photograph to generate a pictorial image with a stippling or sand painting-like touch.

For example, Japanese Patent Laid-Open Publication No. Hei 8-7094 discloses that a density value obtained by inverting and shifting the density value of input image data and the density value of input image data are combined, An image processing method and apparatus for trimming a generated density value so as to converge within a range of first and second thresholds is disclosed.

[0004]

However, in this method and apparatus, the pictorial effect obtained is limited to repetitive patterns such as stippling or sand painting, with the unique hand-drawn touch desired by the user, for example crayon. The problem is that a pictorial image of a touch with a characteristic of carrying a brush, such as a painted picture, cannot be generated.

In this method and apparatus, the degree of shift (shift value), the first and second threshold values,
There is also a problem that it is difficult for the user to intuitively grasp how the degree of the pictorial effect in the obtained image corresponds. Therefore, in order to obtain a pictorial image drawn with a desired touch, the user has to repeat the process from inversion to trimming many times.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and is an image capable of easily generating a pictorial image drawn by a user's desired touch from a document such as a photographic image or a digital camera image. It is an object to provide a processing device.

[0007]

According to one aspect of the present invention, a threshold value corresponding to the density value is determined for each pixel from a first monochrome grayscale image. Threshold value matrix creating means for creating a threshold value matrix; comparing a density value of the second monochrome density image with a threshold value of the threshold value matrix for each corresponding pixel; and based on the comparison result, the second monochrome density image And a binarizing means for binarizing.

[0008] The first monochrome gray-scale image may be read through an image input device provided integrally in the apparatus or separately provided outside the apparatus, or may be prepared in advance and stored in the apparatus. May be stored.
However, when the image is read via the image input device, the range in which the density value of the first monochrome grayscale image can be obtained changes according to the reading characteristics and the setting of the reading density specific to the image input device.

Further, another image processing apparatus according to the present invention comprises:
According to a second aspect of the present invention, in the image processing apparatus according to the first aspect, there is provided a monochrome gray image creating means for creating a first or second monochrome gray image by converting a color image into a monochrome image. It is.

According to a third aspect of the present invention, there is provided an image processing apparatus according to the first or second aspect, wherein a plurality of monochrome grayscale images are stored in advance, and And selecting means for selecting one of the monochrome gray-scale images as the first monochrome gray-scale image and supplying the selected image to the threshold matrix creating means.

According to a fourth aspect of the present invention, there is provided an image processing apparatus according to any one of the first to third aspects, further comprising an image input device and an image output device. It is characterized by being provided integrally inside.

According to a fifth aspect of the present invention, there is provided an image processing apparatus according to any one of the first to fourth aspects, wherein the first monochrome grayscale image is stored in the image processing apparatus. It is characterized by comprising means for normalizing before creating a threshold matrix.

According to a sixth aspect of the present invention, in the image processing apparatus of the fifth aspect, the second monochrome grayscale image is replaced with the first monochrome grayscale image. And a means for normalizing in accordance with a normalization table and a common normalization table.

[0014]

According to the image processing apparatus of the present invention, a threshold matrix is created from the first monochrome grayscale image by the threshold matrix creating means. Specifically, the density value of each pixel of the first monochrome grayscale image is used as a threshold as it is as a threshold matrix, or at least one of normalization, γ correction, and inversion is performed on the first monochrome grayscale image. Is performed to create a threshold matrix.
Thus, the threshold value matrix reflects the touch in the first monochrome grayscale image.

For example, as the first monochrome gray-scale image, if an image drawn by a user using an original material such as a crayon or a pencil or a commercially available screen tone is used, the threshold matrix becomes such an image. In this case, the original touch, that is, the change in density and the movement of the brush peculiar to the painting material are directly reflected.

Then, the threshold value of the threshold matrix thus formed is compared with the density value of a second monochrome gray-scale image such as a photographic image or a digital camera image for each corresponding pixel, and based on the comparison result, When the second monochrome grayscale image is binarized, the touch of the first monochrome grayscale image is left on the obtained binary image.

As described above, according to the present invention, it is possible to create a pictorial image drawn with a user's desired touch.

Further, in this image processing apparatus, since the touch of the image used for creating the threshold value remains in the processing result, the user can intuitively predict the processing result. Therefore, the user can relatively easily obtain a pictorial image of a desired touch without repeatedly performing various processes.

In particular, the image processing apparatus according to the second aspect of the present invention includes a monochrome gray-scale image creating means for creating a first or second monochrome gray-scale image by converting a color image into a monochrome image. There is no need to limit to monochrome grayscale images or to convert color images into monochrome grayscale images in advance. Therefore, this image processing apparatus has high versatility.

On the other hand, in the image processing apparatus according to the third aspect,
Since a plurality of images previously drawn by the user with a unique touch can be stored in the storage means in the apparatus, it is not necessary for the user to create an image of a desired touch each time processing is performed. The effect is that the processing can be simplified as compared with the case where the image read through the image input device is included.

Further, even if the image stored in the apparatus is processed without normalization, the obtained pictorial image is greatly deviated from the atmosphere of the original photograph or digital camera image. That is, the shading of a photograph or a digital camera image does not become crushed or jumped.

Furthermore, in the image processing apparatus according to the fourth aspect, it is not necessary to perform data conversion in consideration of data compatibility between the image input apparatus and the image output apparatus every time input / output of image data is performed. The effect that the question can be shortened is obtained. Further, since only one γ curve specific to the dedicated image output device needs to be prepared, there is an effect that the memory capacity can be reduced.

Incidentally, the maximum density value of the first monochrome grayscale image depends on the black density of the image material, and the minimum density value depends on the color of the paper. If a threshold matrix is created and binarized without considering the factors that cause these density values to change in various ways, the resulting binary image will be significantly different from the atmosphere of the second monochrome grayscale image, That is, the shade of the second monochrome shade image may be crushed or jumped.

The image processing apparatus according to the fifth aspect is capable of avoiding such a problem by providing means for normalizing the first monochrome grayscale image before creating the threshold matrix. . Hereinafter, this point will be described with reference to FIG.
A specific description will be given using (a) and (b).

FIGS. 8 (a) and 8 (b) schematically show the results of binarization when a threshold matrix is created without normalizing the first monochrome grayscale image and when the threshold matrix is created by normalization. FIG. Note that the horizontal axis of the graph indicates the position on a certain line in the image,
The vertical axis indicates the density value. The lower part of the graph shows the result of binarization at each pixel on the image line, corresponding to the horizontal axis of the graph.

Focusing on the high-density portion of the image data indicated by A in the figure, it can be seen that in both FIGS. 7A and 7B, the binarization result reflects the change in the threshold, that is, the strength of the touch. On the other hand, paying attention to the low-density part of the image data indicated by B in the figure, in FIG. 10A, since the threshold values are concentrated on the high-density part as a whole, the binarization results are all white. The shading of the image data jumps. On the other hand, in FIG. 9B, since the density range in which the threshold can be taken is wide, it can be seen that the strength of the touch is reflected without jumping.

Further, when the image obtained as a result of the binarization is output as a printed matter by the printing apparatus via a master made by the plate making apparatus, a factor for increasing the density of the printed matter as a whole, specifically, The threshold matrix may be created by performing γ correction in consideration of the perforation characteristics of the plate making device and the master, and the printing characteristics that change depending on the ink and paper used for printing.

When the first monochrome grayscale image is not as large as the second monochrome grayscale image, the first monochrome grayscale image is enlarged or reduced so as not to destroy the touch atmosphere. It may be. As an example, a method using linear interpolation will be described below.

(L) The vertical magnification and the horizontal magnification are calculated from the sizes of the first and second monochrome grayscale images, and the enlargement (reduction) magnification is set. Note that the vertical and horizontal magnifications may be calculated using the calculated vertical and horizontal magnifications, but here, the case of vertical and horizontal magnification using one of the magnifications will be described.

(2) The coordinate value of the enlarged (reduced) image is divided by the magnification to make correspondence with the coordinates of the first monochrome grayscale image. For example, in the case of the magnification N, if a certain coordinate of the enlarged (reduced) image is (X, Y) and a corresponding coordinate of the first monochrome grayscale image is (Xn, Yn), Xn = X /
N, Yn = Y / N.

(3) The coordinates (X
n, Yn) and the coordinates of the four surrounding points,
From the density value of the coordinates of the point, the coordinates (X,
The density value of Y) is calculated based on the following (Equation 1).

[0032]

(Equation 1)

X 'is the maximum integer not exceeding Xn;
y ′ is the largest integer not exceeding Yn, α = Xn−x ′, β
= Yn-y '.

[0034]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

<< First Embodiment >> FIG. 1 is a block diagram showing a schematic configuration of an image processing apparatus according to a first embodiment of the present invention. As shown in the figure, the image processing apparatus includes an image scanner 11 as an image input device and an image processing unit 12.
And a thermal transfer printer 13 as an image output device.

The image read by the image scanner 11 is input to the image processing unit 12 as a monochrome image quantized into 8-bit data having a density value of 0 to 255 for each pixel. In this embodiment, black is set when the density value is 255, and white when the density value is 0.

FIG. 2 is a block diagram showing a detailed configuration of the image processing section 12. As shown in FIG. The image processing unit 12 includes a threshold matrix creation unit 1 including a first normalization unit 22, a γ correction unit 23, an image inversion unit 24, and a threshold data memory 21, a second normalization unit 25, and a binarization unit. 26, and a binarization processing unit 2.

The first normalizing means 22 and the second normalizing means 25 comprise a black / white detecting means 31, a normalizing table creating means 32 and a density value converting means 33, as shown in detail in FIG. ing.

The thermal transfer printer 13 shown in FIG.
Is for outputting a pictorial image drawn by the user's desired touch, generated by the image processing unit 12, to paper using an ink ribbon.

In the above configuration, processing for generating a pictorial image drawn with a user's desired touch is performed as follows.

First, the processing in the threshold matrix creating section 1 will be described. Here, as an example, an image (hereinafter, referred to as a touch image) drawn by a user using an original material such as a pencil or a crayon (hereinafter referred to as a touch image) is used as the image scanner 11.
The threshold matrix creating unit 1 creates a threshold matrix using this image as a first monochrome grayscale image. FIG. 5A shows an example of the touch image.

The procedure for creating a threshold matrix by the threshold matrix creating section 1 is as follows.

(1) First, the density value of each pixel of the touch image is detected by the black / white detection means 31 of the first normalization means 22 shown in FIG. 3, and the maximum density value Dmax and the minimum density value Dmin are determined. Is extracted. That is, a range in which the density value of the touch image can be detected is detected.

(2) Using the maximum density value Dmax and the minimum density value Dmin,
A normalization table for normalizing the touch image is created. Specifically, as shown in FIG.
An input / output characteristic curve is set in an area sandwiched between x and the minimum density value Dmin, and output density values corresponding to input density values in order are stored. In this embodiment, the input / output characteristic curve is obtained by setting the maximum density value Dmax to the maximum output value and setting the minimum density value Dmin
Is set to a straight line with the minimum output value.

(3) The density value conversion means 33 converts the density value of each pixel of the touch image with reference to the normalization table to obtain a normalized touch image. In addition, black /
As described above, the first normalization unit 22 including the white detection unit 31, the normalization table creation unit 32, and the density value conversion unit 33 determines whether the finally obtained pictorial image is a shading of the original photographic image. This is to prevent the object from being crushed or jumped.

(4) Next, the γ correction means 23 shown in FIG.
As a result, the normalized touch image is transferred to the thermal transfer printer 13.
Is corrected using a γ curve specific to the touch image, and a γ corrected touch image is obtained. The γ correction means 23 is for compensating the gradation reproducibility of the thermal transfer printer 13.

(5) The gamma-corrected touch image is inverted by the image inversion means 24 to obtain an inverted touch image. The image reversing means 24 is for leaving the shade of the touch image as it is in the finally obtained pictorial image.

The inverted touch image is stored in the threshold data memory 21, and the binarizing means 26 of the binarizing section 2 binarizes the photographic image as the second monochrome gray image. This is used as a threshold value in the event.

Next, a processing step in the binarization processing section 2 will be described. Here, the photographic image read by the image scanner 11 is binarized using the threshold matrix created by the threshold matrix creating unit 1. FIG.
(B) shows an example of this photographic image.

(L) First, the photographic image is normalized by the second normalizing means 25 shown in FIG. This normalization is
This is performed by the same processing as that of the first normalizing means 22 described above.

(2) Next, the binarizing means 26 shown in FIG.
The density value of each pixel of the normalized photographic image and the threshold value stored in the threshold data memory 21 are compared for each corresponding pixel, and the photographic image is binarized based on the comparison result. You. Specifically, as shown in FIG. 8B, when the image data is smaller than the threshold value, it is 0 (white), and when it is larger, it is 255 (black). As a result, a pictorial binary image to which the touch feature of the touch image is added according to the density of the photographic image is generated.

The pictorial image obtained as a result of this binarization is
The paper transferred to a predetermined position by a paper feeding means (not shown) is reproduced using the thermal transfer printer 13 and the recorded paper is discharged out of the apparatus. FIG. 6 shows an example of a pictorial image obtained from the first monochrome gray-scale image in FIG. 5A and the second monochrome gray-scale image in FIG. 5B.

As described above, in the first embodiment, the threshold value for binarization is determined from the density value of the image drawn by the user with his or her own touch, so that the obtained binary image has Touch, specifically, a change in density or brush movement peculiar to the painting material can be left as it is. Therefore, photos, digital camera images, etc.
A pictorial image drawn with a user's desired touch can be generated.

In this embodiment, the first normalizing means 23 variously changes the density values such as the setting of the reading characteristics and the reading density of the image scanner 11, the black density of the image material, and the color of the paper. Factor has been eliminated.
Therefore, the obtained pictorial image does not become an image in which the density of a photograph or digital camera image as a manuscript is crushed or jumped.

In this embodiment, the pictorial image obtained by the γ correction means 23 is
It is not affected by the inherent tone reproducibility. Therefore, gradation reproducibility independent of the characteristics of the thermal transfer printer 13 can be obtained. In the present embodiment, the γ correction unit 23 is provided in the threshold value matrix creation unit 1, but may be provided in the binarization processing unit 2.

In the present embodiment, the image inversion means 24 is used so that the shade of the touch of the touch image remains in the obtained pictorial image. Therefore, the user does not need to create an image in which the touch image is inverted in advance.

Even when the touch image is not the same size as the photographic image, as described above, the means for enlarging or reducing the touch image can be used to convert the photographic image of various sizes into a pictorial image. It is possible to generate a value image. For example, in the present embodiment, a touch size changing unit can be inserted before the first normalizing unit 22 to create an enlarged or reduced touch image having the same size as the photographic image. As a result, if the photographic original is relatively large and it is difficult to create a touch image of the same size, it is desirable to enlarge the touch image or leave a finer handwriting-like touch In some cases, a pictorial binary image drawn with a user's desired touch can be generated by reducing the touch image or the like.

In the present embodiment, when the black / white detecting means 31 extracts the maximum density value Dmax and the minimum density value Dmin of the touch image, the density values of all the pixels are detected. The density value may be detected only for pixels sampled to such an extent that the feature of the density change is not lost (specifically, at an appropriate interval that includes the high density portion and the low density portion of the image). . Thereby, the processing time can be reduced.

Further, in the present embodiment, the input / output characteristic curve for normalization is set to a straight line as shown in FIG. 4, but the maximum value is set so that γ correction and inversion processing are performed simultaneously. The curve may be deformed in a region between the density value Dmax and the minimum density value Dmin. This makes it possible to omit the γ correction unit 23 and the image inversion unit 24.

Further, in the present embodiment, the photographic image is normalized by the second normalizing means 25. However, the second normalizing means 25 is not provided, and the density of the original photograph is used as it is. It may be. Alternatively, a plurality of normalization tables having different degrees of density correction may be stored in the apparatus in advance, so that the user can arbitrarily select the tables.

In this embodiment, FIG.
As shown in the figure, the image drawn by the user with his or her own touch is read by the image scanner 11 as a touch image. A plurality of touch images are stored in the apparatus in advance, and the user can arbitrarily select a touch image to be used. It may be possible to do so. This eliminates the need for the user to create a touch image each time.

As described above, the density of the touch image stored in the apparatus is varied in various ways, such as the setting of the reading characteristics and reading density specific to the image scanner 11, the black density of the image material, and the color of paper. Those that do not include factors can be adopted. Then, it is not necessary to provide the first normalizing means 22 for eliminating these factors, so that the processing can be simplified as compared with the case where the image drawn by the user with the unique touch is read by the image scanner 11. .

In the present embodiment, the monochrome image scanner 11 is used as the image input device, but a color image scanner may be used. In that case, the G value of the RGB values of each pixel of the read image is substituted for the density value of the pixel, or the maximum value of the RGB values is substituted for the density value of the pixel, so that the monochrome grayscale image creating means is obtained. And can be made monochrome. This eliminates the need to limit the image to be used to a monochrome grayscale image or to convert the image into a monochrome grayscale image in advance, thereby increasing versatility.

<< Second Embodiment >> FIG. 7 is a block diagram showing a schematic configuration of an image processing apparatus according to a second embodiment of the present invention. In the first embodiment described above, the image input device and the image output device are integrally provided in the device. However, as shown in FIG. 7, a color image scanner 81 as the image input device and a color image scanner 81 as the image output device are provided. An apparatus configuration including a personal computer 82 as an image processing apparatus separately from the inkjet printer 83 may be used. In this case, the same effect can be obtained by installing software for realizing the above-described image processing in the personal computer 82.

Third Embodiment Next, an image processing apparatus according to a third embodiment of the present invention will be described. The image processing apparatus of the present embodiment has basically the same configuration as the image processing apparatus of the first embodiment described above. The difference is that in the first embodiment, the pictorial image finally obtained is directly output on paper using the thermal transfer printer 13,
The third embodiment is that the master is made so that the thermal transfer printer 13 functions as a plate making apparatus and a pictorial print having a desired density of the user can be obtained. Hereinafter, this point will be described.

In general, a printed matter is created by a printing apparatus using a master made by a plate making machine without taking into account the perforation characteristics of the plate making apparatus and the master, and printing characteristics such as ink bleeding that varies depending on the ink and paper used for printing. Then, the density of the obtained printed matter tends to be higher as a whole. Therefore, in this embodiment, in order to prevent the density of the printed matter from increasing, the γ correction unit 23 shown in FIG.
3, a gamma correction table is prepared in advance that takes into account the perforation characteristics of the master and printing characteristics that vary depending on the ink and paper used for printing. As a result, it is possible to make a master plate by eliminating factors that increase the density of a printed material.

Here, as a printing apparatus that creates a pictorial print using a master that has been made, for example, Japanese Patent Application Laid-Open
The device disclosed in JP-A-11875 is preferred. This printing apparatus uses a printing plate created by placing printing ink on a master that has been made, and obtains a printed matter by pressing this plate on paper, and is obtained by the first plate. It is also possible to color the printed matter using a second plate. For example, a printed matter with a touch such as that drawn with crayons obtained by the first edition is colored with a watercolor-like printing ink that is included in the subject of the photograph using the second edition. This makes it possible to obtain a painting-like printed matter as if drawn with crayons and watercolor paints.

As described above, in the third embodiment,
The γ correction means 23 can perform γ correction in consideration of the perforation characteristics of the thermal transfer printer 13 and the master and the printing characteristics that change according to the ink and paper used for printing, so that the density of the printed matter is increased as a whole. It is possible to make a master by eliminating factors. Therefore, if a printed matter is created by a printing apparatus using this master, it is possible to prevent the density of the printed matter from increasing.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of an image processing apparatus according to a first embodiment of the present invention;

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

FIG. 3 is a block diagram showing a schematic configuration of a part of the image processing unit.

FIG. 4 is a graph showing characteristics of a normalization process performed by a normalization unit of the image processing unit;

FIG. 5A is an electrophotograph showing an example of a first monochrome grayscale image, and FIG. 5B is a photograph showing an example of a second monochrome grayscale image.

FIG. 6 is an electrophotograph showing an example of a binary image created by the image processing apparatus of the present invention.

FIG. 7 is a block diagram illustrating a schematic configuration of an image processing apparatus according to a second embodiment of the present invention;

FIG. 8A is a schematic diagram schematically illustrating a binarization result when a threshold matrix is created without normalizing a first monochrome gray image, and FIG. Schematic diagram (b) schematically showing the result of binarization when a matrix is created

[Description of Signs] l Threshold matrix creation unit 2 Binarization processing unit 11 Image scanner 12 Image processing unit 13 Thermal transfer printer 21 Threshold data memory 22 First normalization unit 23 γ correction unit 24 Image inversion unit 25 Second normal Conversion means 26 binarization means 31 black / white detection means 32 normalization table creation means 33 density value conversion means 81 color image scanner 82 personal computer 83 ink jet printer

 ──────────────────────────────────────────────────続 き Continued on front page F term (reference) 5B057 AA11 AA20 BA02 CA01 CA02 CA08 CB01 CB02 CB07 CC01 CD01 CE01 CE08 CE11 CE13 CH07 DB05 DB06 DB08 DC32 5C077 MP08 PP19 PQ22 RR02 RR16 5C079 HA13 LA00 LA31 LA34 MA02 MA04

Claims (6)

[Claims] 1. A threshold matrix creating means for creating, from a first monochrome grayscale image, a threshold matrix which defines a threshold value corresponding to the density value for each pixel; and a density matrix of the second monochrome grayscale image. An image processing apparatus comprising: a binarizing unit that compares a threshold value of a threshold value matrix with each corresponding pixel and binarizes the second monochrome grayscale image based on the comparison result. 2. The image processing apparatus according to claim 1, further comprising: a monochrome grayscale image creating unit that creates a first or second monochrome grayscale image by converting a color image into monochrome. 3. A storage unit in which a plurality of monochrome grayscale images are stored in advance, and a selection unit for selecting one of the monochrome grayscale images as the first monochrome grayscale image and supplying the first monochrome grayscale image to the threshold matrix creating unit The image processing apparatus according to claim 1, further comprising: 4. The image processing apparatus according to claim 1, wherein an image input device and an image output device are integrally provided in the device. 5. The image processing apparatus according to claim 1, further comprising: means for normalizing the first monochrome grayscale image before creating the threshold matrix. 6. The apparatus according to claim 5, further comprising means for normalizing the second monochrome grayscale image in accordance with a normalization table common to a normalization table for normalizing the first monochrome grayscale image. Image processing device.