JP2000078404A - Image processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image processor capable of expressing an image having a halftone with a desired specified character. SOLUTION: A ROM 12 stores a basic matrix and various kinds of font data. Based on the basic matrix, a desired specified character or the like ('A', for example,) inputted from a ten key 16a, an MPU 11 allocates the threshold values of the basic matrix again and prepares a threshold matrix for expressing that specified character pattern or the like. Therefor, by performing dither processing through a dither processing part 22 while using the threshold matrix expressing this specified character, an image having a halftone can be plotted with that specified character. Therefore, when the image is watched from a distant, it is recognized just like a 'picture' painted but when the image is watched from near, it is recognized that 'A' is drawn. Therefore, an advertisement effect can be obtained by combining the 'picture' and the 'desired specified character'.

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 for performing pseudo halftone processing.

[0002]

2. Description of the Related Art For example, in a copying machine or a facsimile machine, a dither method is known as a method of binarizing an image having a halftone. This dithering method is a method of binarizing an image having a halftone using a threshold matrix composed of arbitrary thresholds and performing pseudo gray scale display.

As a threshold matrix composed of arbitrary thresholds, various threshold matrices such as a Bayer type and a spiral type have been proposed. An image having a halftone can be artificially represented by these threshold matrices.

[0004]

However, these conventional threshold matrices are used only for pseudo-representing an image having a halftone, and do not include any other purpose. .

The present invention has been made in view of such a conventional technique, and has as its object to provide an image processing apparatus capable of displaying an image having a halftone with desired specific characters. It is in.

[0006]

In order to achieve the above object, according to the present invention, in an image processing apparatus for performing pseudo halftone processing, a storage means for storing a basic matrix and a specific character are stored. An input means for inputting, and a creating means for creating a threshold matrix expressing characters by reassigning a threshold constituting the basic matrix to a new threshold.

According to a second aspect of the present invention, in the image processing apparatus according to the first aspect, the creating means performs a process of enlarging a range of image density in which a specific character input from the input means appears.

According to a third aspect of the present invention, in the image processing apparatus according to the first or second aspect, the creating unit shifts the threshold matrix for each threshold matrix in the main scanning direction.

In the embodiments of the invention described below, the "storage means" described in the claims or the means for solving the problems corresponds to the ROM 12, and the "input means" corresponds to the operation unit 16. Similarly, the “creating means” corresponds to the MPU 11, the ROM 12, and the RAM 13.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is embodied in a facsimile apparatus will be described below with reference to the drawings.

As shown in FIG. 1, a facsimile apparatus 1 as an image processing apparatus includes an MPU 11, a ROM 12,
M13, reading unit 14, recording unit 15, operation unit 16, display unit 17, image memory 18, codec 19, modem 20,
It comprises an NCU 21 and a dither processing unit 22, and each of the units 11 to 22 is connected via a bus 23.

The MPU 11 controls each part of the facsimile machine 1. The ROM 12 stores a program for controlling the facsimile machine 1. Also, RO
M12 stores the basic matrix K shown in FIG. 2A and various font data. The RAM 13 temporarily stores various data relating to the facsimile machine 1.

The reading section 14 reads image data on a document. Then, the read image data of the multi-valued data is
Based on the processing mode, binarization is performed by simple binarization processing such as fixed slices and pseudo halftone processing such as dither processing.

The recording unit 15 includes an electrophotographic printer,
A thermal printer or an ink-jet printer is used to record received image data and image data of a document read by the reading unit 14 on a recording sheet in a copying operation.

The operation unit 16 includes a numeric keypad (including the * and # keys) 16a for inputting a facsimile number or the like, an abbreviated number registration, and abbreviated key 16 for transmitting from the abbreviated number.
b, a start key 16c for starting an original reading operation, a communication / copy key 16d for setting a “communication (FAX)” operation or a “copy” operation, and a processing mode for the read image data in a halftone mode. Various operation keys such as a halftone key 16e to be set are provided. A display unit 17 such as an LCD displays various information such as an operation state of the facsimile machine 1.

The image memory 18 temporarily stores received image data and image data read by the reading unit 14 and encoded by the codec 19 according to the MMR, MR or MH system.
The codec 19 encodes the image data read by the reading unit 14 for transmission using the MH, MR, MMR method, or the like. The codec 19 decodes the received image data.

The modem 20 conforms to ITU-T Recommendation T.30. 30 based on a facsimile transmission control procedure according to V.30. 1
7, V. 27ter, V.A. Modulation and demodulation of transmission / reception data in accordance with any one of E.29 and the like. The NCU 21 has a function of controlling connection with the telephone line L and detecting transmission and reception of a dial signal corresponding to a fax number of the other party.

The dither processing unit 22 performs dither processing on multi-valued image data read by the reading unit 14 based on the depression of the halftone key 16e of the operation unit 16. A method of creating a threshold matrix for representing a specific character in the facsimile machine 1 configured as described above will be described with reference to FIGS.

First, a case will be described in which a 8 × 8 basic matrix K having thresholds of 1 to 64 is used to create a threshold matrix MA representing “A” as a specific character. As shown in FIG. 2A, a basic matrix K
Based on the character pattern P1 of “A”, only the threshold value corresponding to each pixel constituting the character pattern P1 of “A”
When extracted from the basic matrix K, as shown in FIG. 2B, an extraction matrix KP1 composed of 14 thresholds
Is obtained. Subsequently, “1” is set in ascending order of the obtained threshold.
When the threshold of ".about.14" is newly reassigned, a threshold matrix M1 expressing the character pattern P1 of "A" composed of the new thresholds of "1.about.14" is obtained as shown in FIG. 2C.

Here, the image density having a halftone is "1".
For the uniform image of "4", the character pattern P1 of "A"
When the dither processing is performed using the threshold value matrix M1 representing the following, the character pattern P1 of "A" is obtained.

However, simply performing dither processing on the threshold value matrix M1 representing the character pattern P1 of "A" will cause the character pattern P1 of "A" only in a narrow density range.
Does not appear. In other words, only when the image density is "14", the complete character pattern P1 of "A" appears.
Here, the “perfect“ A ”character pattern P1” means that only the pixels constituting the character are all black. For this reason, when the character pattern P1 of "A" is recorded on the recording paper as it is, an incomplete "A" is displayed at a place where the image density is low, specifically, at a place where the image density is less than "14".
Character pattern P1 of "A"
1 is difficult to recognize.

Therefore, a shadow is added to the character pattern P1 of "A" in order to expand the range of image density in which the character pattern P1 of "A" appears. That is, as shown by the diagonal lines in FIG. 3, ten shadows generated when light is projected from the left to the character pattern P1 of “A” are added to the character pattern P1 of “A”. You do it. In this way, when the image density is in the range of “14 to 24”, the character pattern P1 of “A” or the shaded “A”
Character pattern PA can be represented. In other words,
The same effect as storing a plurality of types of character patterns having different thicknesses as the character pattern P1 of “A” can be obtained. Moreover, by adding shadows,
There is an additional effect that the character pattern P1 of "A" can be expressed in a so-called "bold tone".

Therefore, based on the basic matrix K and the shading pattern P2 of "A" as shown in FIG.
When only the threshold values corresponding to the pixels constituting the shadow pattern P2 of “A” are extracted from the basic matrix K, FIG.
As shown in (b), an extraction matrix KP2 composed of ten threshold values is obtained. Subsequently, when the thresholds of “15 to 24” are newly re-assigned in ascending order of the obtained thresholds, “A” composed of the new thresholds of “15 to 24” as shown in FIG. Is obtained.

Here, the image density having a halftone is "1".
4 to 24 ", the character pattern P1 of" A "
And a threshold matrix representing a shadow pattern P2 of “A”,
That is, when dither processing is performed using a threshold matrix obtained by combining the threshold matrix M1 and the threshold matrix M2, “A” having different thicknesses can be obtained. That is, the image density “14”
In response to “−24”, the character pattern P1 of “A” or the character pattern P1 of “A” obtained by adding the shading pattern P2 of “A” to a part of the character pattern P1 of “A” is obtained. In particular, in the case of a uniform image having an image density of “24”, as shown in FIG.
A is obtained.

Next, as shown in FIG. 5A, based on the basic matrix K and the background pattern P3 of "A",
When only the threshold values corresponding to the pixels constituting the background pattern P3 of “A” are extracted from the basic matrix K, FIG.
As shown in (b), an extraction matrix KP3 composed of 40 threshold values is obtained. Subsequently, when the thresholds “25 to 64” are newly re-assigned in ascending order of the obtained thresholds, “A” composed of the new thresholds “25 to 64” as shown in FIG. Is obtained. A threshold matrix M3 representing the background pattern P3 is obtained.

As described above, when the processes shown in FIGS. 2 to 5 are sequentially performed, as shown in FIG.
6 based on the shaded character pattern PA of “A”.
As shown in (b), the shaded character pattern PA of “A”
Is obtained.

Here, the image density having a halftone is "1".
When the dither processing is performed on the image of “−64” using the threshold matrix MA representing the shaded character pattern PA of “A”, the shaded character pattern PA of “A” corresponding to the image density is obtained. .

That is, when the image density is less than "14",
An incomplete "A" character pattern P1 is obtained. In particular,
When the image density is "14", a complete "A" character pattern P1 is obtained.

When the image density is in the range of "15 to 24", a shaded character pattern PA of "A" is obtained according to the image density. In particular, when the image density is “24”, a complete shaded character pattern PA of “A” is obtained.

Further, when the image density is in the range of "25 to 63", the shaded character pattern "A" is obtained by adding a part of the background pattern P3 "A" to the shaded character pattern PA "A". PA is obtained. In particular, when the image density is "6
In the case of "4", the whole is "black".

Next, a method of arranging the threshold matrix MA representing "A" obtained in this manner will be described with reference to the explanatory diagrams shown in FIGS. As shown in FIG. 7A, threshold matrices MA representing “A” are simply arranged. Then, when dither processing is performed, FIG.
As shown in FIG. 5, the shaded character patterns PA of "A" are recorded on the recording paper in a state of being arranged in the vertical and horizontal directions. For this reason, it looks as if the space between the shaded character patterns PA of “A” is greatly increased. In addition, the shaded character pattern PA of “A” becomes a monotonous image.

Therefore, as shown in FIG.
Is set as one unit, and the threshold matrix MA is shifted from the main scanning direction by half for each threshold matrix MA. Then, when the dither processing is performed, as shown in FIG. 8B, the shaded character pattern PA of "A" is printed on the recording paper in a state shifted by half for each threshold matrix MA. For this reason, the shaded character pattern PA of “A”
The space between the character patterns PA appears to be narrower than the space between the shaded character patterns PA of “A” shown in FIG. 7B. In addition, the shaded character pattern PA of “A” does not become a monotonous image.

Next, the operation of the facsimile apparatus 1 for copying an image having a halftone will be described with reference to FIG.
And a flowchart shown in FIG. This operation is performed under the control of the MPU 11 based on a program stored in the ROM 12.

In step S1 shown in FIG. 9, the user determines whether or not the document is placed on a document table (not shown) constituting the reading section 14. Specifically, the determination is made based on a detection signal from a document presence / absence sensor (not shown) arranged opposite to the document table. If it is determined that a document is placed, the operation state changes from the standby state (during power saving) to the operation state, and the process proceeds to step S2. If it is in the operating state, the process proceeds to step S2 as it is.

In step S2, it is determined whether the halftone key 16e of the operation unit 16 has been pressed. If the halftone key 16e has been pressed, the process proceeds to step S5. On the other hand, when the halftone key 16e is not pressed,
It is determined that the copy is normal, and the process proceeds to step S3.

In step S3, the start key 1
It is determined whether or not 6c has been pressed. Then, when the start key 16c is pressed, the process proceeds to step S4. In step S4, a normal copy operation is performed. That is, the original is read by the reading unit 14 and recorded on the recording paper by the recording unit 15.

In step S5, the step S5
Since the halftone key 16e is pressed in 2, the processing mode of the read image data is set to the halftone mode, and a message to the effect that the halftone mode has been set is displayed on the display unit 17.

In step S6, a message inquiring whether or not to perform dither processing on a specific character (for example, when performing dither processing on a specific character ... "1", when not performing dither processing on a specific character ... " 0 ”) is displayed on the display unit 17.

In step S7, the numeric keypad 16a
It is determined whether the "1" key has been input. If it is determined that the “1” key of the ten keys 16a has been input, the process proceeds to step S11 shown in FIG. On the other hand, if the "0" key of the ten key 16a has been input, the process proceeds to step S8.

In step S8, the start key 1
It is determined whether or not 6c has been pressed. Then, when the start key 16c is pressed, the process proceeds to step S9. In step S9, normal dither processing is performed. That is, the document is read by the reading unit 14, the dither processing is performed by the dither processing unit 22, and the document is recorded on the recording paper by the recording unit 15.

In step S11 shown in FIG.
A message to input a specific character is displayed on the display unit 17. In step S12, the user
When it is determined that a specific character (for example, “A”) or the like has been input from the numeric keypad 16a, the R
From the OM 12, the data of the specific character is read.
Then, the data of the specific character is transferred to the dither processing unit 22 and the display unit 17.

In step S13, the specific character transferred in step S12 is displayed on the display unit 17. In step S14, it is determined whether or not start key 16c has been pressed. Then, when the start key 16c is pressed, the process proceeds to step S15.

In step S15, a threshold matrix representing the specific character transferred in step S12 is created by the method described above. That is, in step S12, when the input specific character is, for example, “A” as the specific character, the input specific character “A” is recognized as the character pattern P1 of “A”. Subsequently, for the character pattern P1 of "A",
Shading is added to form a shaded character pattern PA.
Then, a threshold matrix MA is created based on the shaded character pattern PA.

In step S16, based on the threshold matrix created in step S15,
The dither processing section 22 performs dither processing. Step S
At 17, the image is recorded on the recording paper by the recording unit 15.

Next, FIGS. 12 and 13 show an example in which dither processing is performed on the image having the halftone shown in FIG. 11 with the specific character "A". FIG. 12 shows a case where dither processing is performed by simply arranging the threshold matrices MA in the vertical and horizontal directions. FIG. 13 shows a threshold matrix MA.
In the main scanning direction is shifted by a half for each threshold matrix MA to perform the dither processing.

As shown in FIGS. 12 and 13, it is recognized that a “picture” is drawn when viewed from a distance, and a “picture” is drawn as “A” when viewed from a distance. It will be recognized.

As described above, according to the present embodiment, the following operations and effects can be obtained. (1) When the threshold value of the basic matrix K is reassigned based on the basic matrix K and the desired specific character (for example, “A”) input from the numeric keypad 16a, the threshold value representing the specific character pattern PA with shading A matrix MA is created. Therefore, when dither processing is performed using the threshold matrix MA representing the specific character, an image having a halftone can be drawn with the specific character (“A”).
Therefore, when viewed from a distance, it is recognized that “picture” is drawn, and when viewed from near, it is recognized that “A” is drawn. Therefore, an advertising effect can be obtained by combining the "picture" and the "desired specific character".

(2) Basic matrix K and numeric keypad 16
Based on a specific character (for example, “A”) input from “a”, a threshold matrix MA representing the specific character is created. Therefore, a threshold matrix representing a specific character is not stored. That is, as long as only the basic matrix K and the specific character pattern are stored, any specific character can be represented by the threshold matrix. As a result, the storage capacity can be reduced. Therefore, a threshold matrix representing a specific character can be created based on the minimum data.

(3) A shade is added to a specific character input from the numeric keypad 16a. Therefore, specific characters having different thicknesses appear in a wide density range. Moreover, by adding a shadow, the specific character is expressed in a so-called "bold tone". Therefore, an image having a halftone in a wide density range can be reliably represented by a specific character.

(4) A threshold matrix representing a specific character is 1
As a unit, for each threshold matrix in the main scanning direction,
Displaced by half. For this reason, when the dither processing is performed, it is expressed in a state shifted by half for each threshold value matrix. That is, when the specific characters are recorded on the recording paper, it appears that the interval between the specific characters is narrowed. Therefore, an image having a halftone drawn with a specific character does not become a monotonous image.

(5) Character pattern P1, shadow pattern P
2 and the background pattern P3 are compared with the basic matrix K each time, and after extracting matrices (KP1, KP2, KP3) are created, new thresholds are reassigned. In other words, the extraction matrix KP2 of the shadow pattern P2 is not created based on the extraction matrix KP1 of the character pattern P1. Further, the extraction matrix KP3 of the background pattern P3 is not necessarily created based on the extraction matrix KP2 of the shadow pattern P2. For this reason, the time required to create a threshold matrix representing a specific character can be reduced. Therefore, even when an image having a halftone is copied, dither processing can be performed quickly.

(6) The threshold value is newly re-assigned based on the input specific character (for example, “A”). Therefore, the arrangement of the thresholds in the basic matrix may be arbitrary. Therefore, a threshold matrix that represents a specific character can be created for any basic matrix including different thresholds.

The above embodiment can be embodied with the following modifications. Specific characters input from the numeric keypad 16a include graphic characters (numerical characters, Western characters, ideographic characters, kana, kanji, special characters), control characters (transmission control characters, format control characters, code extension characters, device control characters) Such characters may be used.

The font style of the specific character may be any style such as Mincho, Gothic, and Italic. -The specific character may be a sentence. In this way, an image having a halftone can be drawn in text, and a message can be conveyed by the text. Therefore, an advertising effect can be further obtained.

A basic matrix other than the 8 × 8 basic matrix composed of the threshold values of 1 to 64 may be used. Specifically, a 16 × 16 basic matrix or a 32 × 32 basic matrix may be used. If you do this,
Even if the font is a kanji composed of many pixels and having a large number of strokes, an image having a halftone can be displayed using the basic matrix.

In the case where the total number of strokes of the input specific character is large (especially kanji), a threshold matrix expressing the specific character is created without changing the character pattern without shading the character pattern. You may.

Even when the image density having a halftone is low, a new threshold value may be re-assigned so that a specific character appears as much as possible. Specifically, according to the image density,
A new threshold value may be reassigned so that the entire specific character appears little by little.

In order to prevent a halftone image drawn with a specific character from becoming a monotonous image, the values for shifting the threshold matrix are not only half of the threshold matrix, but also
Any value may be used.

In order to enlarge the image density range in which the character pattern appears, a plurality of shadow patterns may be added according to the font size. Specifically, when the font size is small (for example, when the font size is 18 points or less)
For example, the number of shadow patterns to be added may be reduced, and the number of shadow patterns to be added may be increased when the font size is large (for example, when the font size exceeds 18 points).

The shadow pattern to be added to the character pattern is not limited to the case where light is projected from the left, but may be a shadow generated when light is projected from the right, above or below. Further, a combination of a plurality of them may be used.

In the flowcharts shown in FIGS. 9 and 10, the processing of setting the halftone mode, setting the dither processing, and setting the specific character by pressing the halftone key 16e is as follows.
Instead of a series of processes with the recording process, another process may be performed in which only each of the setting processes is performed.

Further, technical ideas other than the claims grasped from the above embodiments and the like will be described below together with their effects. [1] The image processing apparatus according to any one of claims 1 to 3, wherein the creating means creates a threshold matrix representing a specific character so as to appear in a wide density range.

With this configuration, an image having a halftone can be reliably represented by a specific character. [2] In the image processing apparatus according to any one of claims 1 to 3, the creating means creates a character pattern, a shadow pattern, and a background pattern based on the basic matrix, and creates a shaded character pattern. Image processing device to create.

With this configuration, it is possible to reduce the time required for creating a threshold matrix representing a specific character.

[0065]

Since the present invention is configured as described above, it has the following effects. According to the first aspect of the present invention, an image having a halftone with desired specific characters can be displayed.

According to the invention described in claim 2, according to claim 1
In addition to the effects of the invention described in (1), an image having a halftone in a wide density range can be reliably represented by specific characters. According to the third aspect of the invention, in addition to the effects of the first or second aspect, an image having a halftone drawn with a specific character does not become a monotonous image.

[Brief description of the drawings]

FIG. 1 is a circuit configuration diagram of a facsimile apparatus according to one embodiment.

FIG. 2 is an explanatory diagram for explaining a method of creating a threshold matrix in a character pattern.

FIG. 3 is an explanatory diagram showing a shaded character pattern.

FIG. 4 is an explanatory diagram for explaining a method of creating a threshold matrix in a shaded character pattern.

FIG. 5 is an explanatory diagram for explaining a method of creating a threshold matrix in a background pattern.

FIG. 6 is an explanatory diagram for explaining a threshold matrix representing “A”;

FIG. 7 is an explanatory diagram for explaining an image that appears when dither processing is performed using a threshold matrix in a case where the pixels are simply arranged.

FIG. 8 is an explanatory diagram for explaining an image that appears when dither processing is performed using a threshold matrix in which the pixels are arranged by being shifted by half in the main scanning direction.

FIG. 9 is a flowchart showing an operation when copying an image having a halftone.

FIG. 10 is a flowchart showing an operation when copying an image having a halftone.

FIG. 11 is an explanatory diagram showing an image having a halftone.

FIG. 12 is an explanatory diagram showing an example in which threshold matrices representing “A” are arranged in up, down, left, and right directions to perform dither processing.

FIG. 13 is an explanatory diagram showing an example in which a threshold matrix representing “A” is shifted by half in the main scanning direction and dither processing is performed.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Facsimile machine as an image processing apparatus, 11 ... MPU which comprises a creation means, 12 ... ROM which comprises a storage means and a creation means, 13 ... RAM which comprises a creation means
16: operation unit as input means; 22: dither processing unit for performing pseudo halftone processing.

Claims (3)

[Claims] 1. An image processing apparatus for performing pseudo halftone processing, comprising: a storage unit for storing a basic matrix; an input unit for inputting a specific character; And a creating means for creating a threshold matrix representing the following. 2. The image processing apparatus according to claim 1, wherein the creating unit performs a process of expanding a range of an image density in which a specific character input from the input unit appears. 3. The image processing apparatus according to claim 1, wherein the creating unit shifts the threshold matrix for each threshold matrix in the main scanning direction.