JPH0754959B2 - Image processing device - Google Patents

Description

TECHNICAL FIELD The present invention relates to an image processing apparatus for synthesizing images and line images such as characters.

2. Description of the Related Art Conventionally, when a character is superimposed on a halftone image, for example, a well-known copying apparatus is used to copy the halftone image,
The copy paper obtained thereby was used as a printer paper this time in a printer device capable of hard copying characters, and the characters were superimposed on the halftone image. However,
Such a method is not practical because it is troublesome twice and there are many complicated problems such as difficulty in aligning an image and a character. On the other hand, as shown in FIG. 1, a conventional copying machine and line printer (for example, laser beam printer)
There is known a composite-type copying machine in which and are combined. In the apparatus shown in FIG. 1, a copy image of an original placed on the original table 50 and an external device (not shown) (for example, a host computer)
It is to be printed out on the copying machine 61 by superimposing it on the printer character output input from the signal line 63 from the printer. The document table 50 is exposed by the exposure lamp 51,
The reflected light from 50 is imaged on the surface of the photosensitive drum 59 via the mirrors 51 to 55 and the lens 56, and an electrostatic latent image corresponding to the original is formed. On the other hand, the character information input to the interface control circuit 62 from an external device (not shown) is
In 62, it is converted into dot data, and the laser light from the semiconductor laser 64 is modulated and output. Reference numeral 57 is a rotary polygon mirror for horizontally scanning the laser light. In this way, by controlling the laser light and scanning it, an electrostatic latent image of a character image is formed on the surface of the photosensitive drum 59 in the same manner as described above so as to be superimposed on the electrostatic latent image. After that, in the same process as in ordinary electrophotography, such as development->transfer-> fixing, the final halftone image and characters are superimposed to obtain a copied image. However, in this apparatus, since the halftone image and the character image are processed independently and printed out, even if the character is overlaid on the image having many black areas, the character is discriminated as shown in FIG. The problem of difficulty arises. In particular, the characters superimposed on the solid part cannot be identified.

The present invention has been made in view of the conventional drawbacks, when performing image formation by synthesizing an image according to halftone color image data for each color component and an image according to character pattern image data, Image processing that enables good discrimination of an image corresponding to the character pattern image data even if the halftone color image data and the character pattern image data overlap, regardless of whether or not the halftone color image data is a dark tone portion. The purpose is to provide a device.

In order to achieve such an object, the image processing apparatus of the present invention comprises first generating means (in this embodiment, FIG. 21) for generating halftone color image data obtained by performing halftone processing on color image data for each color component. (Corresponding to FIG. 8), second generating means for generating character pattern image data in which the character code data is expanded (corresponding to FIG. 3 in this embodiment), and determining means for determining the dark tone portion of the halftone color image data ( (This embodiment corresponds to FIG. 35 in FIG. 3), and when the image corresponding to the halftone color image data output for each color component from the first generating means and the color component corresponding to the color designation data are formed, the second Forming means for forming a composite image by sequentially forming an image corresponding to the character pattern image data output from the generating means on the same recording surface of the recording medium in a color sequential manner (in the present embodiment, output from FIG. Picture (Corresponding to 1, 2, 3, 4, 5 which forms an image according to data), the forming means outputs only the halftone color image data on the recording surface. In the area, an image corresponding to the halftone color image data is formed, and the output of both the character pattern image data and the halftone color image data overlaps each other, and the area is determined to be a dark tone portion by the determination means. In this case, an image corresponding to the character pattern image data and an image corresponding to the halftone color image data are not formed in a portion corresponding to the character pattern image data, and the character pattern image data and the halftone color image data are not formed. If the output is an area where both outputs overlap and it is not determined to be a dark tone portion by the determination means, it is determined according to the character pattern image data. And forming a color corresponding to the image on the color specifying data.

Examples Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 3 is a block diagram showing the entire embodiment of the present invention.
In the illustrated image processing apparatus, a character code string signal as shown in FIG. 4 is used as the character image data 101, and R, G, B color identification signals 1 as shown in FIG. 7 are used as the color image data.
04 and the image signal 105 accompanied by the vertical and horizontal synchronizing signals 106V and 106H are supplied from the outside. Further, image trimming position specifying signals 102, 103, 107, 108 are also supplied from the outside.

FIG. 4 shows a character image data string signal, which is the character string data on the first line following the start identification code ITOP of one character image.
Includes C ₁₀ , C ₁₁ , C ₁₂ ……. A RET code is inserted after the last character on each line. Therefore, when the RET code is detected on the receiving side (that is, the image processing apparatus side), a line feed is performed. In FIG.
R ₁ is the RET code on the first line and R ₂ is the RET code on the second line. After the last line in the one-character image, the end code IEND of the one-character image is inserted to end the one-character image data. The image processing apparatus identifies the end of the one-character image by receiving this IEND code.

The character image data 101 supplied as described above is stored in the character code buffer 10 for one screen. At this time, the above-mentioned special code (for example, ITOP code, RET code, IEND code) is decoded by the character code decoder 11, and the storage start / line feed command signal 109 and the storage end signal 110 for storing the character image are transmitted. .

FIG. 5 shows an example of the character screen thus stored. Here, each character A, B, ... A, B, C, ... Is represented by, for example, an 8-bit ASCII code. In this embodiment, since the laser beam method using a dot image is adopted, it is necessary to convert the above-mentioned character code string into a dot shape. Therefore, in the present embodiment, the dot conversion is performed using the character generator 9. Since the character generator 9 is the same as the well-known one, its explanation is omitted. At this time, an area information signal 102 (that is, information designating the row and column of the character code image) indicating which area of the one-character image supplied from the outside should be printed out is given from the external device.

For example, in the character code image shown in FIG. 5, the printout start character and end character are (m ₁ , n ₁ ) to (m ₂ ,
When given by n ₂ ), the area within the illustrated bold line is read from the character code buffer 10. And area information signal 10
Printout designation information (m ₁ , n ₁ ), (m ₂ , n included in _2
In response to ₂ ), the read position designation circuit 17 and the read address generator 18 generate the read address of the designated area.

On the other hand, the designation signal 103 designates a region in the print image where the character image region designated as described above should be printed out. The writing area for printout is given by the pixel number at the writing start position, the scanning line number (m ₁ ′, n ₁ ′), and the same number at the writing end position (m ₂ ′, n ₂ ′). A write address for the image memory 8 is generated by the write position designation control circuit 15 and the image memory address generator 14.

The character code image in the specific area thus read out from the character code buffer 10 is converted into dot data by the character generator 9, and the image data is stored in the image memory 8.
It is stored in the designated area to be printed out. This state is shown in FIGS. 6A and 6B.

Next, the processing of the color halftone image supplied as the density data of each color of R, G, B will be described. This halftone image is
As shown in FIG. 7, it is composed of R, G, B color identification signals 104, vertical and horizontal synchronizing signals 106V, 106H, and density data (that is, an image signal) 105 for each pixel of the image.
Each color image is stored in the buffer memory 28-1, 28-2, 28-3 for each color in accordance with the R, G, B color identification signal 104.

Synchronous signals 106V and 106H are address generators for storage
The address selector 30 supplies the necessary address to the image buffer memories 28-1, 28-2, 28-3. Thus, each color image is stored in the image buffer memory.
It is stored in each of 28-1, 28-2, 28-3.

After that, similarly to the reading from the character code buffer 10, the area 107 in which the halftone image is to be printed out is designated by the signal 107 supplied from the outside. This is given with the printout start point, the pixel number, and the scanning line number, and the address of the corresponding image memory 28-1, 28-2, 28-3 is generated from the read address generator 31.

At the time of reading, an image buffer memory for yellow (Y) (stores a B signal) 28-1 and an image buffer memory for magenta (M) (stores a G signal) 28-
The same pixel is simultaneously read out as Y, M, and C components from the image buffer memory 28-3 for cyan (C) (which stores the R signal) 28-3. (Here, the complements of the B, G, and R signals are taken and output as the Y, M, and C signals.)
The color signal thus read is finally stored in the image memory 21 for halftone images, but the image area designated as described above is printed out at the designated position. Signal 10 supplied from outside (not shown)
The write start position is specified by 8. In response to this, the image memory writing position designating circuit 23 and the image memory address generator 22 generate the address of the image memory 21 corresponding to the designated position. This operation is similar to the case of the character image data described above.

The color density data for each pixel read from the image buffer memory 28-1, 28-2, 28-3 is stored in the gamma correction circuit.
In 27, gamma conversion (density conversion) matching the characteristics of this image processing device is performed, and masking processing (see 26) and UCR processing (see 25) well known in the printing technology field are performed.
Then, after receiving dither processing (see 24), it is stored as dot data at the specific position in the image memory 21 designated as described above. Here, as is well known, the dither process is an electrical process for determining print dots to be output by comparing density data for each pixel with a threshold value in order to reproduce a halftone.

On the other hand, 35 and 36 are dark tone memories for storing the dark tone extraction circuit and the dark tone portion, respectively. The dark tone extraction circuit 35, as shown in FIG.
Comparing circuits 42, 43, 44, switches 46, 47, 48 and the like.
The switches 46, 47, and 48 set the amount of each density component of Y (yellow), M (magenta), and C (cyan) that should be discriminated as a dark tone. The comparison circuits 42, 43, 44 compare the Y, M, C components of the input image density with the set values set by the switches 46, 47, 48, and determine whether the input image density component amount exceeds the set value. On the other hand, "1" is output. When the input image densities of all Y, M and C exceed the set values, the outputs of the comparator circuits 42, 43 and 44 are 42-1, 43-
Since 1,44-1 are all "1", this pixel is regarded as a dark part and the dark tone memory 36 shown in FIG.
Stored in. At this time, the data writing to the dark tone memory is performed in accordance with the address 118 generated from the address generating circuit 22 by being addressed from the outside (not shown) in the same manner as the storage in the image memory for the halftone image. Further, in this configuration, by changing the set values of the switches 46, 47 and 48 shown in FIG. 8, the color regarded as dark tone can be freely changed. For example, if the switches 46 and 47 are set to high density and the switch 48 is set to zero, the part where Y and M are high density and C is low density, that is, the "red" part becomes a dark tone, and this is It is possible to use the "color".

In order to read out the data from the image memory 8 for character images and the image memory 21 for halftone images and send it to the laser light modulation circuit 5, these image data are stored in the image memories 8 and 21 and the dark tone memory 36, respectively. It is stored as data, and the same address is assigned to the same pixel. In this embodiment, the addressing of both the image memories 8 and 21 and the dark tone memory 36 is performed by the image memory address generator 14
Is in control. That is, both image memories 8 and
A read address is generated at the time when the image is stored in 21, so that the characters corresponding to the same pixel, the halftone image, and the dot data of the dark tone portion are transmitted.

The dot data of the character image read from the image memory 8 and the dot data of the halftone image read from the image memory 21 act exclusively. That is, when a character is output and printed out, the character portion is a print dot (115 = "1") and the value for the same pixel read from the ground portion, that is, the dark tone memory is "1" ( That is, when the ground is dark tone), the output of the AND gate 37 is "0", and a white character is output. When the ground portion is "0", that is, white or light-colored, the output of the AND gate 37 is "1", and characters are printed.

On the other hand, when printing a halftone image, if the character portion is a print dot, that is, the signal 115 = "1", the output of the AND gate 38 is "0" regardless of the image data 116, so there is no character There is no image. Therefore, the white color is realized. That is, halftone image data is output only in the part without a character (11
It is when 5 = "0"). In this way, the output image is as shown in FIG. 9, for example. As you can see from the figure, the parts with dark tone or solid black parts are white letters,
White areas can be printed out with black or other monochrome characters (described below). 39 is a selector for characters and halftone images, and by the signal 114 output from the control circuit 16,
When outputting a character image, A and C are controlled to be connected, and when outputting a halftone image, B and C are controlled to be connected.

The dot data read from the image memories 8 and 21 modulate the laser light. The modulated laser light forms an electrostatic latent image on the photosensitive drum 1. The process of creating a print image is the same as a normal laser beam printer,
Four types of developing devices (none of which are shown) are selectively used for Y, M, C, B _K (black). Further, the signal 113 indicates that when the laser beam is applied to the laser beam detector 40,
This is a horizontal synchronization signal sent from the detector 40, and causes the image data read from the image memories 8 and 21 to be performed in synchronization.

This image processing apparatus first reads a yellow image, operates a yellow developing device (not shown) to obtain a yellow image, and then sequentially aligns magenta, cyan, and black in a similar process. The four-color full-color image is obtained by overlapping.

The signal 112 is a signal for controlling the color of the character image,
The data is output from the image memory 8 only when the desired color is printed out. Similarly, the image memory 21
It is also possible to obtain a single-color or complex-color image by controlling to read out only a desired color image when reading out a halftone image from.

Therefore, as described above, when printing out characters in yellow, for example, if only the switch 46 in FIG. 8 is set to high density and the other 47 and 48 are set to low density, only the yellow part of the halftone image will be printed. As such, the yellow character and the halftone image can be clearly distinguished.

FIG. 6 shows an example in which the designated areas of the character image and the halftone image are individually moved and the two images are combined. That is, the regions are moved with respect to the input images A and C, respectively, and the obtained images B and D are obtained.
To obtain an image B + D.

In this embodiment, the character pattern is stored in the image memory, but other line drawing patterns may be stored. Further, in the present embodiment, the laser beam printer was described as an example of the output device, but the present invention is not limited to this, and can be used in, for example, an inkjet printer, a thermal printer, or the like.

As described above, according to the present invention, the image corresponding to the halftone color image data output for each color component and the character pattern image data during the formation of the color component according to the color designation data are formed. When a composite image is formed by sequentially forming the images on the same recording surface of the recording medium in a color sequential manner, it is an area where the outputs of both the character pattern image data and the halftone color image data overlap and the halftone Even if the color image data is a dark tone, the image can be identified well according to the character pattern data.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a composite type copying apparatus, FIG. 2 is a diagram showing a state in which characters are superimposed on an image with many black portions, and FIG. 3 is a configuration diagram showing an entire embodiment of the present invention. , FIG. 4 is a diagram showing an example of character image data, FIG. 5 is a diagram showing an example of a character screen stored in a character code buffer, and FIG. 6 is a diagram showing the designated regions of a character image and a halftone image separately. It is a figure which shows an example which moved and moved and synthesize | combined these both images. FIG. 7 is a diagram showing an example of color image data, FIG. 8 is a concrete configuration diagram of a dark tone extraction circuit, and FIG. 9 is a diagram showing an image state obtained by this embodiment. 8 …… Character image memory 9 …… Character generator 10 …… Character code buffer 11 …… Character code decoder 12 …… Interface 14 …… Image memory address generator 15 …… Image memory write position designation circuit 16 …… Control Circuit 17 …… Read position designator 18 …… Read address generator 19 …… Write address generator 20 …… Address selector 21 …… Image memory for halftone images 22 …… Image memory address generator 23 …… Specify image memory write position Circuit 24 …… Dither circuit, 25 …… UCR circuit 26 …… Masking circuit 27 …… Gamma correction circuit 28-1, 28-2, 28-3 …… Image buffer memory 29 …… Interface 30 …… Address selector 31… … Read address generator 32 …… Write address Nereta 33 ...... read position designation circuit 35 ...... dark tone extraction circuit 36 ...... dark tone memory 39 ...... selector 42-44 ...... comparator circuit

Claims (1)

[Claims] 1. A first generating means for generating halftone color image data in which halftone processing is performed on color image data for each color component, and a second generating means for generating character pattern image data in which character code data is expanded. Determination means for determining a dark tone part of the halftone color image data; formation of an image corresponding to the halftone color image data output from the first generation means for each color component and a color component corresponding to the color designation data. And an image processing device for forming a composite image by color-sequentially forming an image corresponding to the character pattern image data output from the second generating unit on the same recording surface of the recording medium. Then, the forming unit forms an image corresponding to the halftone color image data in an area where only the halftone color image data is output on the recording surface. When the output of both the character pattern image data and the halftone color image data overlaps and the determination means determines that the output is a dark tone portion, the character pattern is included in the portion corresponding to the character pattern image data. An image corresponding to the image data and the image corresponding to the halftone color image data are not formed, and an area where the outputs of both the character pattern image data and the halftone color image data overlap and a dark tone is generated by the determining means. An image processing apparatus, characterized in that, when it is not determined to be a copy, an image corresponding to the character pattern image data is formed in a color corresponding to the color designation data.