JP2001218021A - Picture processing method and picture processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a picture processing method and a picture processor, which can correct a gradation skip while the quality of a whole picture is maintained. SOLUTION: In LUT, it is set whether random data is added or not at every area in color picture data displayed by address bit '1' and '2' (data bit 7). Then, ON/OFF of random number addition can be switched in accordance with a character area or an area out of the character area (address bit '0'). Thus, random number data is added only in the area where the correction of the gradation skip is required and the remaining area can maintain an original picture.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an image processing method and an image processing apparatus.

[0002]

2. Description of the Related Art In recent years, there has been a remarkable development of a digital copying machine for copying an image by electrically reading an original and outputting the obtained image data on paper.
With the rapid growth of the technology in the copying machine industry, it has become possible to provide beautiful color images with higher image quality and higher accuracy to users.

[0003] One of the problems in improving the image quality of a copying machine is the problem of image gradation skipping. This is especially true when outputting an image that changes smoothly over continuous gradations, such as gradation, because the toner characteristics of the copying machine do not change in proportion to the image gradations. ,
This is a phenomenon in which the difference in toner density differs between the preceding and following gradations for each gradation, and a portion having a large difference in density appears as a streak in an image.

[0004] As a method of solving this problem of gradation skip, a very small random number signal is added to image data in an area where the density difference between gradations is large when outputting a gradation image. Then, there is a method of correcting a gradation jump by filling a level difference between gradations and smoothing the gradation.

However, this method adds a signal that does not exist in the original image, and may adversely affect the image depending on the image. Therefore, it is necessary to switch ON / OFF of the random number addition processing.

As a method of switching the random number addition, for example, there is a method in which a box indicating the random number addition mode is displayed on the operation unit and the user selects whether or not to perform the random number addition. When printing out the gradation image transferred from the host side in the copying machine, the host side outputs a flag signal for random number addition processing,
On the main unit side, random number addition is controlled depending on the presence or absence of the flag signal.

[0007]

However, in the above-mentioned conventional method, random number data is added to the entire output image area. Therefore, for example, when an image to be printed includes an image for which random numbers should not be added in addition to a gradation image, the image quality may be degraded.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and an object of the present invention is to output a high-quality image by accurately performing random number addition only on an image area to which the random number is to be added. An image processing apparatus and an image processing method are provided.

[0009]

In order to achieve the above object, the present invention provides an image reading step of reading an image on a document and converting the image into color image data; An area setting step of setting an area to be added, and only the color image data of the set area,
And a random number adding step of adding random number data.

In the area setting step, it is characterized in that whether or not random number data is added is set separately for a character area in the color image data and for an area outside the character area.

An image reading step of reading an image on a document and converting the image into color image data; an adding step of adding a gradation image to the color image data; and a partial area of the color image data to which the gradation image is added in the adding step And a random number data adding step of adding random number data to the image data.

The random number data adding step includes a setting step of setting whether to add random number data separately for a character area in the color image data and an area outside the character area.

Image reading means for reading an image on a document and converting the image into color image data; area setting means for setting an area to which random number data is added in the color image data; And random number adding means for adding random number data.

The area setting means sets whether to add random number data separately for a character area in the color image data and an area outside the character area.

Image reading means for reading an image on a document and converting the image into color image data; adding means for adding a gradation image to the color image data; and a partial area of the color image data to which the gradation image is added by the adding means And random number data adding means for adding random number data to the image data.

The random number data adding means includes setting means for setting whether to add random number data separately for a character area in the color image data and an area outside the character area.

The random number data adding means includes an LUT for determining whether to add random number data for each partial area in the color image data.

[0018] The LUT is included in coloring means for determining coloring for each partial area in the color image data.

A storage medium storing a computer program for processing color image data read from an original, wherein the computer program sets a partial area in the color image data to which random number data is added. A code for an area setting step and a code for a random number adding step for adding random number data only to the color image data in the set area are included.

A storage medium storing a computer program for processing an image obtained by combining a gradation image with color image data read from a document, wherein the computer program stores a portion of the color image data to which the gradation image is added. And a code for adding random number data to the image data of the area.

[0021]

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the relative arrangement of components described in this embodiment, formulas, numerical values, etc., unless otherwise specified,
It is not intended to limit the scope of the present invention only to them.

(Embodiment) <Outline> In this embodiment, when an output image includes a gradation image to which random numbers should be added and an image to which random numbers should not be added, an area where a gradation image exists is determined. ON / OFF of the random number addition process is switched between the other image areas. For example, an image area to be output is divided into several areas using a digitizer or the like, and an area to which random numbers are to be added is specified by a simple operation.

<Main Body Configuration> A color copying machine as an embodiment of an image processing apparatus according to the present invention will be described in detail with reference to FIGS.

FIG. 1 is a schematic sectional view of a color copying machine according to the present embodiment.

This apparatus has a digital color image reader 100 at the upper part and a digital color image printer 2 at the lower part.
00.

In the reader section 100, the original 30 is placed on an original platen glass 31, and a known original scanning unit including an exposure lamp 32 is driven by an optical reading drive motor 35 to a predetermined fixed magnification determined according to a preset copying magnification. Exposure scanning at the speed of The reflected light image from the original 30 is condensed by a lens 33 on a full-color sensor (CCD) 34,
A color separation image signal is obtained. As this full-color sensor, R (red), G
A three-line CCD provided with (green) and B (blue) filters is used. The color-separated image signal is subjected to image processing in an image processing unit 36 and a controller unit 37, and is sent to a printer unit.

An operation unit is provided around the platen glass 31, and switches for setting various modes related to a copy sequence, a display and a display are arranged.

In the printer section 200, the photosensitive drum 1 as an image carrier is rotatably supported in the direction of the arrow, and a pre-exposure lamp 11, a corona charger 2,
A laser exposure optical system 3, a potential sensor 12, four developing units 4y, 4c, 4m, and 4Bk of different colors, an on-drum light amount detecting unit 13, a transfer device 5, and a cleaning unit 6 are arranged.

In the laser exposure optical system 3, the reader unit 1
The image signal from 00 is converted into an optical signal by a laser output unit (not shown), and the converted laser light is reflected by the polygon mirror 3a, passes through the lens 3b and the mirror 3c,
The image is projected on the surface of the photosensitive drum 1.

At the time of image formation by the printer unit 200, the photosensitive drum 1 is rotated in the direction of the arrow, and the photosensitive drum 1 after having been neutralized by the pre-exposure lamp 11 is uniformly charged by the charger 2, so that each of the separated colors is The light image E is irradiated to form a latent image.

Next, by operating a predetermined developing device, the latent image on the photosensitive drum 1 is developed, and a toner image based on a resin is formed on the photosensitive drum 1. The developing units 4y, 4
c, 4m, and 4Bk are eccentric cams 24y and 24, respectively.
According to the operations of m, 24c, and 24Bk, the photosensitive drum 1 is arranged so as to be selectively approached in accordance with each of the separated colors.

Further, the toner image on the photosensitive drum 1 is
The image is transferred from one of the preselected recording material cassettes 7 a, b, and c to the recording material supplied to a position facing the photosensitive drum 1 via the transfer system and the transfer device 5. The selection of the recording material cassette is performed by driving any one of the pickup rollers 27a, 27b, and 27c according to a control signal from the controller unit 37 in advance according to the size of the recording image.

In the present embodiment, the transfer device 5 includes a transfer drum 5a,
A transfer charger 5b, a suction roller 5g opposed to a suction charger 5c for electrostatically sucking the recording material, an inner charger 5d,
A recording material carrying sheet 5f made of a dielectric material is integrally stretched in a cylindrical shape in a peripheral opening area of a transfer drum 5a having an outer charger 5e and rotatably supported by a shaft. .
The recording material supporting sheet 5f uses a dielectric sheet such as a polycarbonate film.

As the transfer device in the form of a drum, that is, the transfer drum 5a is rotated, the toner image on the photosensitive drum is transferred by the transfer charger 5b onto the recording material carried on the recording material carrying sheet 5f.

As described above, a desired number of color images are transferred to the recording material sucked and conveyed to the recording material carrying sheet 5f to form a full-color image.

In the case of forming a full-color image, when the transfer of the toner images of four colors is completed in this way, the recording material is separated from the transfer drum 5a by the action of the separation claw 8a, the separation push-up roller 8b and the separation charger 5h. The sheet is discharged to the tray 10 via the roller fixing device 9.

On the other hand, after the transfer, the photosensitive drum 1 is subjected to the image forming process again after the residual toner on the surface is cleaned by the cleaning device 6.

When forming images on both sides of a recording material,
Immediately after the fixing unit 9 is ejected, the transport path switching guide 19 is driven, and once guided to the reversing path 21a via the transport vertical path 20, the rear end of the sheet fed by the reverse rotation of the reversing roller 21b is moved to the top. And is retracted in the direction opposite to the direction in which the sheet is fed, and stored in the intermediate tray 22. Thereafter, an image is formed on the other surface again by the above-described image forming step.

Further, in order to prevent scattering of powder on the recording material carrying sheet 5f of the transfer drum 5a and adhesion of oil on the recording material, the brush is moved through the fur brush 14 and the recording material carrying sheet 5f. 14, a backup brush 15, an oil removing roller 16, and a recording material carrying sheet 5.
Cleaning is performed by the action of the backup brush 17 facing the roller 16 via f. Such cleaning is performed before or after image formation, and when a jam (paper jam) occurs.
It is performed as needed when it occurs.

In this embodiment, the gap between the recording material carrying sheet 5a and the photosensitive drum 1 is reduced by operating the eccentric cam 25 at a desired timing and operating the cam follower 5i integrated with the transfer drum 5f. The configuration can be set arbitrarily. For example, during standby or when the power is off, the interval between the transfer drum and the photosensitive drum is increased.

<Image Processing Block> With reference to FIGS. 2A and 2B, the flow of data processing in the image processing section 36, the controller section 37, and the peripheral controlled sections will be described.

First, a configuration and a control flow used for the entire image processing from scanning of a document to printing will be described, and thereafter, an area generating circuit and an area generating circuit, which are important components in the present embodiment, will be described. The random number adding circuit and the coloring circuit will be described in more detail.

The full-color sensor (CCD) 34 has 10
It is composed of 1, 102, 103 red, green, and blue three-line CCDs, and color-separates one line of light information from a document to R, G, B at a resolution of 400 dpi.
Output an electrical signal.

For example, a maximum of 297 mm as one line
(A4 portrait), CCD can read R, G,
B outputs a 4677 pixel image per line.

Reference numeral 106 denotes a CCD drive signal generation unit.
-Decode ADR to generate a reset pulse and a CCD-DRIVE signal as a transfer clock from a CCD shift pulse. As a result, the R, G, and B color separated image data for the same pixel is sequentially output from the CCD 34 in synchronization with VCLK.

Reference numeral 107 denotes an A / D converter which is a CCD 3
Each of the red, green, and blue image data output from 4 is converted from an analog signal to an 8-bit digital signal.

Reference numeral 150 denotes a shading correction circuit.
This is a circuit for correcting variations in signal output for each pixel in the CCD. The shading correction circuit 150 has a memory for one line of each of R, G, and B signals, reads an image of a white plate having a density predetermined by an optical system, and uses the read image as a reference signal.

Reference numeral 151 denotes a sub-scanning connection circuit, which is a CCD
34 is a circuit for absorbing the displacement of the image data read by 34 in the sub-scanning direction by 8 lines.

Reference numeral 152 denotes an input masking circuit for removing dust from the R, G, and B colors in the input image data.

153 and 163 are buffers, and ZO
-When the ED signal is at the L level, the image data is passed, and ZO-
When the ED signal is at the H level, the image data is not passed.
When the editing function is used, it is usually at the L level.

A filter 155 in the editing circuit unit 154 smoothes image data, and performs a 5 × 5 matrix operation. Reference numeral 156 denotes a color conversion circuit, and RGB
Has a function of converting the image data into the HSL color space coordinates, converting the color specified in advance to another specified color, and returning to the RGB color space again. It is also possible to convert a multi-value signal into a binary signal at a fixed threshold value.

Reference numeral 159 denotes an external device, which comprises a memory device for storing image data up to A3 size, a computer for controlling the memory device, and the like. External device 159
Image data is red, green, blue (RGB)
The signal is output in the form of a signal, a cyan, magenta, yellow, black (CMYK) signal, or a binary signal.

When a gradation image is output, a flag signal GRAD for notifying that the image data is a gradation image is supplied to a subsequent interface (I
/ F) Supply via circuit 158.

The I / F circuit 158 is a circuit for matching the timing and speed between the image data from the external device 159 and the internal image data.

An area generating circuit 160 generates and stores an area specified by an editor or the like.
In addition, M which extracts an image of a marker pen or the like drawn on a manuscript
The ARKER signal is also stored in the memory as an area area. Further, the SC-BI signal obtained by binarizing the image data read by the CCD 34 is converted into Z-B
Used for I output signal.

For example, when a rectangular area region signal is generated, the coordinates of two vertexes of the diagonal of the rectangle are specified by an editor or a digitizer. The coordinate information specified by the editor or the like is transmitted to the area expansion I via the CPU.
C (not shown), the area extension IC calculates a rectangular area based on the sent coordinate information of the two points, and stores it in the memory as an area area. At the time of the printing operation, A
Output as REA signal. Based on the AREA signal and the image signal, the area area information stored in the memory is read and edited.

The memory write section and the memory read section for the area in the area generation circuit 160 will be described later in detail.

Reference numeral 157 denotes an RGB synthesizing circuit.
4 and the external device 15
9 is a circuit for synthesizing RGB image data. It is also possible to combine RGB image data from the CCD 34 with a binary image from an external device.

The area to be synthesized is specified by the AREA signal from the area generation circuit 160 or by the IPU-BI signal from an external device. For the composition, replacement composition in which image data from the CCD 34 and image data from the external device 159 are independently composed for each area, and watermark composition in which two images are simultaneously superimposed and combined with each other are also possible. is there. In this watermark synthesis, it is also possible to specify a watermark rate of which of two images is to be watermarked and synthesized.

Reference numeral 161 denotes a contour generating circuit,
Contours are extracted from an SC-BI signal obtained by binarizing the image data read by the above, an IPU-BI signal which is binary data from an external device, or a binary data Z-BI signal from an area generating circuit. Generate shadows.

Reference numeral 162 denotes a black character determination circuit which determines the characteristics of the input image data, and outputs eight types of character thickness signals (thickness degree) FTMJ, edge signal EDGE, and color signal I.
Outputs RO.

A black character LUT 172 performs various processes according to the output of the black character determination circuit 162. For example, UC
The R-SL signal is developed by changing the UCR amount of the output masking circuit 110 and developing the image by increasing the amount of black and decreasing the amounts of C, M, and Y in an area determined to be a darker character. Perform processing. In the EDGE-SL signal, the smoothing circuit 169 and the edge emphasizing circuit 170 are set to switch to a filter such that the edge of a black character area is emphasized as the area is blacker. Further, in the SNS-SL signal, the output of the black character LUT 172 is switched by the laser controller 115 between 400 lines and 200 lines under PWM control. In other words, development is performed with 400 lines to increase the resolution in an area determined to be a black character, and development is performed with 200 lines in other image areas to increase the gradation.

A color space compression circuit 108 performs the following matrix operation (1).

[0064] Here, X represents the minimum value of R, G, and B.

By setting in advance whether or not to perform color space compression in the color space compression circuit 108, ON / OFF of the color space compression is performed by the area signal AREA.
Can be switched.

Reference numeral 175 denotes an area LUT (look-up table) circuit. An AREA signal supplied from the area generating circuit 160 is provided below the address terminal.
/ F) The GRAD signal supplied via the circuit 158 is input, and each mode is set according to the AREA signal and the GRAD signal. The LOGCD signal output from the area LUT 175 is used to switch the LOG table of the LOG conversion 109 to through setting or the like, the UCRCD signal is trimmed or masked by the output masking 110, and the FCD signal is the F value of the F value correction 166. Or change it.

The ACD6 signal is supplied to the coloring circuit 165.
The NCD signal is connected to the MCYK synthesizing circuit 164, and the KCD signal is connected to the black character LUT circuit 172, for setting various modes.

Reference numeral 109 denotes a light-density conversion unit (LOG conversion unit) which converts red, green, and blue 8-bit light signals by logarithmic conversion into cyan (C), magenta (M),
The density signal is converted into a yellow (Y) 8-bit density signal.

Reference numeral 173 denotes a buffer that passes image data when the ZO-PRV signal is at an L level and blocks image data when the ZO-PRV signal is at an H level. Normally, the level is H level, and when the preview function is used, the level is L level.

Reference numeral 174 denotes a thinning control circuit which is used when a preview function is used. At the time of preview, the input image data is FIFO
The same signal is output every four lines by writing to the memory.

Reference numeral 110 denotes an output masking processing unit which extracts a black density signal from the C, M, and Y density signals by a known UCR process (under color removal process).
A known masking operation for removing color turbidity of the developer corresponding to each density signal is performed to generate each density signal of M ′, C ′, Y ′, and K ′. In the selector 111, ZO−
Based on the TONER signal, the generated M ′, C ′,
A signal of a color corresponding to the developer currently used is selected from the density signals of Y 'and K'.

The ZO-TONER signal is a 2-bit signal generated from the toner color generation circuit 178 for this color selection. When the ZO-TONER is 0, the M 'signal is output, and when the ZO-TONER is 1, In this case, the signal C '
When −TONER is 2, the Y ′ signal is ZO-TON
When ER is 3, the K 'signal is output as a READ-DT signal. Note that the toner color generation circuit 178 directly outputs the SLTNR signal output from the CPU 130 according to the development color during normal copying as a ZO-TONER signal. At the time of preview, a signal sequentially switched to 0123 for each line is output.

Reference numeral 164 denotes a CMYK synthesizing circuit,
4 is a circuit for synthesizing the image data read by C.4 and the CMYK format image data input from the external device 159. When CMYK synthesis is performed, a color signal corresponding to the developer currently used is input from an external device for each page in accordance with image data from the CCD. The area to be synthesized is the same as that of the RGB synthesis circuit 157.
Switching is performed by the EA signal or the IPU-BI signal. Similarly, watermark synthesis is also possible.

Reference numeral 165 denotes a coloring circuit which performs processing such as adding a preset color to a monochrome image, for example. Coloring can also be performed on the binary image data IPU-BI from the external device 159. Further, it is possible to create a gradation pattern in which the gradation gradually changes. Also, a gradation pattern for gradation editing is generated here, and it is possible to perform coloring with a different pattern according to the area region and the character / contour / shadow region. The detailed configuration of the coloring circuit 165 will be described later.

Reference numeral 166 denotes an F value correction circuit which performs gamma processing according to the development characteristics of the printer and can set the density for each mode.

Reference numeral 114 denotes a scaling circuit which has a memory for one line of image data, and enlarges or reduces image data in the main scanning direction or performs italics for outputting an image obliquely. At the time of sampling, the sampling data is stored in a memory and used for creating a histogram.

Reference numeral 168 denotes a texture circuit.
The color image data read in step 4 is combined with a binary pattern of the image data read in advance by the CCD 34 or a binary pattern input from the external device 159 and output.

Reference numerals 169 and 170 denote a smoothing circuit and an edge emphasizing circuit, each of which comprises a 5.times.5 filter.

Reference numeral 176 denotes a preview conversion unit which performs a thinning process in the main scanning direction at the time of preview (400d).
(pi → 100 dpi conversion) is output to the monitor 177.

Reference numeral 171 denotes an add-on circuit which outputs image data in a specific coded pattern.

Reference numeral 180 denotes a random number addition processing section which adds random number data to image data and outputs the image data when performing a specific image processing.

Reference numeral 115 denotes a laser and laser controller, which controls the light emission amount of the laser according to a VIDEO signal which is an 8-bit density signal. This laser light is scanned in the axial direction of the photosensitive drum 1 by the polygon mirror 3a to form a one-line electrostatic latent image on the photosensitive drum 1.

Reference numeral 116 denotes a photodetector provided in the vicinity of the photosensitive drum 1, which detects the passage of laser light immediately before scanning the photosensitive drum 1 and detects a one-line synchronization signal BD.
Occurs.

Reference numeral 104 denotes a synchronizing signal generation circuit, which comprises a main scanning address counter, a sub scanning address counter, and the like. The main scanning address counter is cleared for each line by a BD signal which is a synchronization signal of laser recording for each line on the photosensitive drum 1, and is cleared by the pixel clock generator 10.
5 is counted, and a count output H-ADR corresponding to each pixel of one line of image information read from the CCD 34 is generated. The H-ADR counts up from 0 to 5000, and one line of image data from the CCD 34 can be sufficiently read.

The synchronizing signal generating circuit 104 outputs various timing signals such as a line synchronizing signal LSYNC, a main scanning effective section signal VE and a sub-scanning effective section signal PE of image data.

Reference numeral 118 denotes a photo sensor, which is a transfer drum 5
a is detected at a predetermined position, and a page synchronization signal IT is detected.
An OP is generated, and the sub-scanning address counter of the synchronization signal generation circuit 104 is initialized via the AND circuit 120 and the OR circuit 119.

Reference numeral 130 denotes a CPU, which controls image reading and image recording operations. 131 is a reading motor 1
5 is a controller that controls forward / reverse and speed. Reference numeral 132 denotes an I / O port for controlling other sensors and actuators required for controlling the copying operation. The I / O port 132 also includes a PF signal for feeding paper from a paper cassette. As another signal, the size of the paper is detected by a paper size sensor (not shown) attached to the paper cassette, and the I / O port 1
32 is input to the CPU 130. Reference numeral 51 denotes an operation unit for instructing the number of copies and various operation modes.

A ROM 133 stores programs to be executed by the CPU 130 and predetermined set values. Reference numeral 134 denotes a RAM that temporarily stores data and stores newly set values and the like.

<Area Generation Circuit> FIG. 13 is a diagram showing a memory writing section of the area generation circuit 160.

The input signal VI1 corresponds to the MARKER signal in FIG. 2A, is an image signal of 400 dpi, and receives four types of binarized image signals.

A line memory (FIFO) 300 can store data for 5120 pixels. Signal VI1
Is delayed by one line in the FIF 0300 to generate a signal VI2.

Reference numeral 301 denotes a flip-flop (F / F) and A
It consists of an ND gate and removes isolated points of one pixel of the signal VI1. 302 also removes an isolated point of one pixel of VI2 similarly to 301. The outputs of the circuits 301 and 302 are A
Input to ND gate 303.

Reference numeral 304 denotes a circuit for ORing signals of four pixels, which is composed of four flip-flops and an OR gate. 305 is an OR gate, and 306 is an AND gate. A FIFO 308 can store data for 5120 pixels.

Reference numeral 307 denotes a signal from the FIFO 308 as AN
This is a circuit for control by the D gate 306, and enables the AND gate 306 for three lines out of four lines. The OR gate 305 outputs an image signal of 16 pixels, that is, 4 pixels in the main scanning direction and 4 pixels in the sub-scanning direction. This is a FIFO control signal and generates a read enable signal and a write enable signal.

Reference numeral 310 denotes a serial / parallel conversion. Here, by inputting a quarter clock, the input signal is thinned to a quarter. Further, the signal VO1 for 16 pixels is written into the page memory 313 at a time while timing is measured by the F / F 311 and the selector 312. VO1 is written once every four lines and once every 64 clocks. That is, since the image signal is thinned out to one-fourth in each of the main scanning and sub-scanning, the image becomes an image equivalent to 100 dpi. 314 is a control signal for the page memory 313, and is a write enable signal MWE.
N and the address signals MAD, RAS, and CAS signals.

A FIFO 320 delays VX1 by one line to generate VX2. 321 is composed of a flip-flop (F / F) and an AND gate.
The isolated point of one pixel is removed from the output VX1 of No. 5.

Similarly to 321, 322 is 1 to VX1.
The line-delayed VX2 is input to remove an isolated point of one pixel. The outputs of the circuits 321 and 322 are input to an AND gate 323.

Reference numeral 324 denotes a circuit for ORing signals of four pixels, which is composed of four flip-flops and an OR gate. 325 is an OR gate, and 326 is an AND gate. 328 is a line memory (FIFO), and 512
Data for 0 pixels can be stored.

Reference numeral 327 denotes the signal from the FIFO 328 as AN.
This is a circuit for controlling by the D gate 326, and the AND gate 326 is enabled for three lines in four lines. The OR gate 325 outputs an image signal of 16 pixels, that is, 4 pixels in the main scanning direction and 4 pixels in the sub-scanning direction, respectively. This is a FIFO control signal and generates a read enable signal and a write enable signal.

Reference numeral 330 denotes a serial / parallel converter. Here, the input signal is further thinned to a quarter by inputting a 1/16 clock. Further, a signal for 16 pixels is written into the page memory 313 at a time while timing is measured by the F / F 331 and the selector 332. The selector 333 selects the area data VO1 and the search data VO2. VO2
Is selected once every 16 lines and 25 times.
Once every 6 clocks. That is, the image signal is 25 dpi
It becomes a considerable image.

FIG. 15A is an address map for writing to the page memory. From address 00000h to 7
Up to FFFFh is a memory space for search, R, G, B,
The area corresponding to each black color is divided into four blocks. Also, from address 80000h to FFFF
The area up to Fh is an area memory space, and is divided into four blocks corresponding to each color of R, G, B and black.

FIG. 16 is a diagram showing the timing of the control signal when writing to the page memory. FIG. 16 shows the timing for each fourth line, and four area image signals are written at different addresses every 64 clocks. In the first, second, and third lines, writing to the memory is not performed.

FIG. 17 is a diagram showing the timing of every 16th line among the control signals when writing to the page memory.

While writing four area image signals every 64 clocks, the selector SLXM is switched every 256 clocks to write four search image signals to different addresses.

FIG. 14 is a diagram showing a memory read section of the area generation circuit 160.

Reference numeral 401 denotes eight F / Fs, and the image signals read from the page memory 313 are latched by any one of the F / Fs 401 at the same timing.

Reference numeral 402 denotes a parallel-serial conversion circuit, which serially outputs image signals for 16 pixels one by one. 403 and 404 are FIFOs, each of which is 1
The image signal is delayed by two lines and two lines, and the same image signal is output by four lines. An F / F 405 receives a quarter clock.

An interpolation circuit 406 performs a 3 × 3 interpolation operation. That is, the image signal here is 400 dp
It becomes an image signal corresponding to i.

FIG. 15B is a diagram showing an example of a memory map at the time of memory reading. An edited area of each color is assigned to each of the eight blocks. Here, the point represents an area edited after being designated by a point in advance, and the loop represents an area edited after being designated by a closed area in advance. k is the area of the black image.

FIG. 18 is a timing chart at the time of memory reading. As shown in FIG. 18, image signals are read one by one from eight blocks every 64 clocks. Also,
The address of the image to be read is updated every four lines.

<Sequence> Next, the control flow of this embodiment will be described with reference to the flowchart of FIG.

First, an arbitrary area to be edited of a black-and-white document is marked in advance with a color marker or the like, for example, a red marker.

The original is set on the original platen, and step S90
By pressing the copy start key in step 1, step S
In step 902, the optical system pre-scans the document and reads an image signal. Each of the read RGB image signals is converted into an HSL space in step S903, and a marker signal of three colors of R (red), G (green), B (blue) and The image is binarized as a Bk (black) image signal. This marker signal is obtained at step S
At 904, the image signal is input to the memory controller of the area generation circuit, and the image signal thinned out every four pixels and every four lines is written to the area memory for each color.

Further, image signals thinned out every four pixels and every four lines are written into the search memory for each color. Then, in step S905, the CPU or the area controller searches the search memory for the address where the R image signal is written. Next, by searching the address of the R image signal in the area memory based on the address searched in the search memory, the position surrounded by the red marker can be accurately searched. Further, step S906
Paints the area surrounded by the address corresponding to the position of the red marker. By performing such processing at other addresses, a 3-bit area code signal is generated.

In step S907, the optical system reads the original again, and the image signal is read. Also, in step S908, the area code signal is read from the memory,
It is output while being subjected to parallel-serial conversion. In addition, the output is performed while performing a 3 × 3 interpolation operation based on signals for three pixels and three lines, and image editing corresponding to the area code area, for example, paint processing is performed. Then, in step S909, the image signal is developed by the developing device and output to a sheet.

<Addition of Random Number Data> FIG. 3 is a block diagram of the random number addition processing section 180 in FIG. 2B.

Reference numeral 210 denotes a block for generating a random number signal to be added to the image data by the random number generation unit.

Reference numeral 220 denotes a random number maximum value calculation unit, which is a block for calculating the maximum value of the random number signal. A random number addition amount calculation unit 230 is a block that calculates a random number addition amount according to the gradation in order to adjust and add the maximum value of the random numbers to be added according to the gradation of the image.

Numeral 240 denotes a random number addition amount selection unit. In the random number data obtained for each section by the random number addition amount calculation unit 230 according to the gradation of the input image data, a section corresponding to the gradation of the image data is selected. Is a block for selecting and outputting random number data.

Reference numeral 250 denotes a random number adder which is a block for adding random number data to input image data.

Reference numeral 260 denotes a selector which selects and outputs one of the image data subjected to the random number addition processing and the input image data.

Reference numeral 270 denotes a register section, which is constituted by a register group, and the set value of each block is set as a register value via the CPU.

The selector 26 is operated by an input from the operation unit 51.
Control of random number addition can also be performed by controlling 0.

FIG. 4 is a block diagram of the random number generator 210.

The random number generation section 210 is provided for the shift register group 21
1 and an ExOR gate 212.

The shift register 211 is reset when the power is turned on.

A selector 213 is a shift register 21.
1 is switched. The selector 213 can switch to the select signal A or B by the register 270.

When the select signal is A, the shift register 211 is set at the timing when the image leading edge signal of the first line arrives.
Is loaded for each color.

When the select signal is B, the shift register 211 is loaded according to the load signal set by the register 270. When the load signal of the shift register 211 becomes active, the shift register 211 reads the load input signal input to the load input terminal. The load input signal can be set by the register 270.
The shift register 211 repeats the shift operation in synchronization with the loaded signal in synchronization with the image clock signal. The output of the shift register 211 is output to the EOR gate 212 by the subsequent ExOR gate 212.
xOR is performed and output as random number data.

FIG. 5 is a block diagram of the maximum random number calculating section 220.

The maximum random number calculating section 220 mainly includes the multiplier 221
It is constituted by. When the random number source signal is input from the random number generation unit 210, the random number maximum value calculation unit 220 multiplies the random number source signal by the other input signal, that is, the random number maximum value signal, and sets the maximum value of the random number to the random number maximum value. The signal is adjusted and output to the value indicated by the value signal. The value of the maximum random number signal can be set by the register 270.

FIG. 6 is a block diagram of the random number addition amount calculation section 230.

In this embodiment, the random number addition calculating section 230
Is to change the maximum value of the random number data to be added to the image data, particularly according to the gradation. This is to prevent the gradation from being partially and extremely changed due to the addition of the random number data.

The random number addition amount calculating section 230 is mainly composed of multipliers 231a to 231c for each gradation section. The random number addition amount calculation unit 230 includes random number data input from the random number maximum value calculation unit 220, tone threshold signals 1 and 2 indicating change points of the tone at which the maximum value of the random number switches, and image data to be added. , The maximum value is calculated for each section, and random number data having the calculated value as the maximum value is output. The threshold data of the tone threshold signals 1 and 2 can be set by the register 270. This will be described with reference to FIG.

As shown in FIG. 10, the random number addition amount calculating section 230 divides all gradations (255 gradations in this example) of image data into several sections, here three sections A to C. Then, the maximum value of the random number is calculated for each section, and the random number data corresponding to the maximum value is output. Sections A to C are
It is divided by the gradation threshold values 1 and 2 set by the register 270. That is, the section A is divided from the gradation 0 to the gradation threshold 1, the section B is divided from the gradation threshold 1 to the gradation threshold 2, and the section C is divided from the gradation threshold 2 to the gradation 255.

The maximum value of the random number data of each gradation in the section B is a random number signal output from the random number maximum value calculation unit 220 uniformly.

The maximum value of the random number data of each gradation in section A is
It differs according to each gradation and is based on the following equation.

Maximum value = random number signal / grayscale threshold 1 × grayscale The maximum value of random number data of each grayscale in section C differs according to each grayscale, and is calculated by the following equation.

Maximum value = random number signal / (255-gradation threshold value 2) × (gradation-gradation threshold value 2) In each of the equations, the random number signal is the random number output from the maximum random value calculating section 220. It is a signal and the gradation is a gradation for which the maximum value of the random number data is to be obtained.

FIG. 7 is a block diagram of the random number addition amount selection unit 240.

The random number addition amount selecting section 240 mainly includes a comparator group 2 composed of comparators provided for the sections A to C described above.
41 and a selector 242.

The random number addition amount selection unit 240 compares the gradation of the input image data with the gradation indicated by the gradation threshold signal 1 or 2 in the comparator group 241. As a result of the comparison, the input image An interval selection signal for notifying which interval the data corresponds to is supplied to the selector 242. Selector 24
2, random number data for each gradation section is input from the random number addition amount calculation section 230 at the preceding stage, the selector is switched according to the section selection signal, and the random number data of the corresponding section is selected and output.

FIG. 8 is a block diagram of the random number adding unit 250.

The random number adding section 250 mainly includes a flip-flop group 251, a selector 252, an adder 253, and an addition timing generating section 254.

In this embodiment, in order to shift the position of the random number to be added to the image, the position of the random number to be added is alternately changed one pixel at a time in the main scanning direction for each line.

Then, in order to cancel the added amount of the random numbers, control is performed so that random number data having a polarity different from that of the random number data two pixels before is added to a position corresponding to a position two pixels after the added random number in the main scanning direction. It shall be. For example, at a position two pixels after the addition of the random number data, control is performed so that the random number data is subtracted from the input image data.

FIG. 11 is a diagram showing this processing. The white circles and the black circles in the figure are random number data, and the random numbers in the black circles are as follows.
The random number value and the absolute value of the white circle two pixels before in the main scanning direction are common and have opposite signs.

The input A of the selector 252 in the random number adder 250 receives random number data and a polarity signal, and the input B is an inverted version of the random number data and the polarity signal two pixels before the one pixel delayed by the flip-flop 251. Is entered.

The addition timing generator 254 is a block for controlling the select signals A and B, which are timing signals for adding random numbers to image data, and receives an image clock signal and a main scanning synchronization signal.

FIG. 12 shows the generation timing of the select A signal and the select B signal. The select A signal and the select B signal are each activated at a cycle of four pixels, and the phase relationship between the select A signal and the select B signal is generated so as to have a phase difference of two pixels. Further, the generation phases of the select A signal and the select B signal are controlled so as to be alternately shifted by one pixel in the main scanning direction for each line.

The select A signal and the select B signal generated by the addition timing generation section 254 are
When the select A signal is active, the selector 252 outputs the random number data and the polarity signal input to the A terminal, and when the select B signal is active, the selector 252 outputs the random number data and the polarity signal to the B terminal.
The inverted random number data and the polarity signal before the pixel are output.

Further, the random number data and the polarity signal selected by the selector 252 are input to the subsequent adder 253 together with the image data. The adder 253 performs addition / subtraction processing of the random number data with respect to the image data. The addition / subtraction is controlled by the input polarity signal. When the polarity signal is “L”, the addition is performed, and when the polarity signal is “H”, the subtraction is controlled.

The image data subjected to the addition / subtraction processing is subjected to overflow and underflow control. If the calculation result at the time of addition exceeds the maximum value (255 for 8 bits) of the image data, the maximum value is obtained. When it becomes negative, each is controlled to be zero. Random number adder 2
The output of 53 is supplied to the subsequent-stage selector 260 as image data obtained by adding random number data.

FIG. 9 is a block diagram of the selector 260. The selector 260 is a block that selects and outputs one of image data subjected to the random number addition processing and image data not subjected to the random number addition processing.

When the RCD signal as the random number addition ON / OFF control signal supplied from the coloring circuit 165 is "L", the input image signal is output as it is to the switching terminal of the selector 260 as through image data of the random number addition processing unit. When the RCD signal is "H", image data subjected to random number addition processing is output. In other words, if the image area is an area specified by the user to add random numbers via an editor or the like, control is performed so that random numbers are added to the image. For other image areas, Control is performed such that the input image is output as it is without performing random number addition.

<Gradation Image> In the present embodiment, gradation editing is performed by the coloring circuit 165 of the image processing section 36.

As the gradation image, there are various shapes such as an image in which a continuous gray image changes in proportion to each unit step gradation, an image in which the gradation gradually increases or decreases with a certain period, and the like. A pattern is assumed. Gradient editing includes anything that outputs only a gradation pattern, one that outputs as a background of an image pattern, one that specifies and outputs an area using a digitizer, or one that outputs a gradation of characters or image patterns. Arbitrary gradation editing is possible.

The present embodiment is characterized in that the random number addition processing is considered as a part of the gradation editing, and a table for determining whether or not to perform the random number addition processing is included in the coloring table of the coloring circuit 165.

<Coloring Circuit 165> FIG. 22 is a simple block diagram of the coloring circuit 165.

Reference numeral 510 denotes an area decoding unit for coloring according to an AREA signal output from the area generation unit 160 and a BI-DT signal of a character (character / contour / shadow) area signal output from the outline generation unit 161. A color code signal indicating a pattern to be output is output.

Here, as an example, the AREA signal is 2 bits and the BI-DT signal is 1 bit (only the character area signal)
It shows about the case of. Area decoding section 510 is configured with a look-up table (LUT).

The LUT is composed of the number of sheets necessary for setting various modes. In FIG. 20, the area LUT is composed of eight sheets of various coloring patterns LUT.

An AREA signal is input to the higher-order addresses bit1 and bit2 of the address terminals of the various LUTs.
The BI-DT signal is input to the lowest address bit0. Thereby, the mode setting according to the area to be edited is set to the corresponding address of each table.

Here, the RCD signal is recognized as a kind of coloring code signal for controlling gradation editing, that is, coloring with a gradation pattern. In FIG.
LU for setting RCD signal when recognized in this way
An example of T is shown. Since the AREA signal is composed of 2 bits and the BI-DT signal is composed of 1 bit, it is specified whether or not to perform coloring (addition of random numbers) with a gradation pattern for each of the character area of the four area areas and the outside of the character area. can do. Here, the area where the AREA signal bit1 is “0” and bit2 is “0” is defined as the editing area 0, bit
The area where 1 is “1” and bit 2 is “0” is the editing area 1 and b
An area where it1 is “0” and bit2 is “1” is an editing area 2, and an area where bit1 is “1” and bit2 is “1” is an editing area 3.

Now, as an example, let us consider a case where the user designates the character area of the editing area 0 and the area other than the characters, and the editing area 2 and the area other than the characters of the editing area 3 as the areas for performing the gradation editing. Assuming that when the RCD signal output from the LUT is "0", the random number addition is OFF, and when the RCD signal is "1", the random number addition is ON, data bit7 may be set as shown in the figure. That is, LUT
Address 0 corresponding to the character area of the edit area 0, bit 1 is "0", bit 2 is the area of "0",
It0 is “1”, bit1 is “0”, and bit2 is “0”
Address, bit0 corresponding to the non-character area of the editing area 2 is “0”, bit1 is “0”, bit2 is “1”, and address bit0 corresponding to the non-character area of the editing area 3 Is "0" and bit1 is "1" and b
Data bit7 is set to "1" in the area where it2 is "1", and data is set to "0" in the other areas.

Reference numeral 520 denotes a coloring section which performs various coloring processes on the input image signal from the preceding buffer 163 or the CMYK synthesizing circuit 164 in accordance with the coloring code signal supplied from the area decoding section 510,
The color-corrected image signal is output to the value correction circuit 166. The RCD signal of the coloring code signal supplied from the area decoding unit 510 is connected to the random number adding unit 180, and performs ON / OFF control of random number addition.

With the above configuration, in the present embodiment, a color original is scanned, multi-valued full-color image information of the original is fetched, and the color image data that has been subjected to data processing by the image processing unit is converted into an image. Forming an electrostatic latent image on a carrier, visualizing the electrostatic latent image formed on the image carrier, transferring the visible image to a recording material carried on a recording carrier, and multi-valued When forming a full-color output image of the image processing unit, in the image processing unit, a gradation-like image generated on a computer by an area input unit for determining an image form of the color image data having a plurality of image forms for each area Control is performed so that irregular random number data is added to the image data and output to the area designated to output the image, and the random number data is not added to the other areas. To control so as to output remains.

Through this control, the user can arbitrarily designate an image area to be subjected to random number addition processing for suppressing gradation jump, which is a problem when outputting a gradation image, to the area input means.

According to the present invention, a recording medium storing software program codes for realizing the functions of the above-described embodiments is supplied to a system or an apparatus, and the computer (or CPU or MP) of the system or the apparatus is supplied.
It goes without saying that the object of the present invention is also achieved when U) reads and executes the program code stored in the recording medium.

In this case, the program code itself read from the recording medium realizes the novel function of the present invention, and the storage medium storing the program code constitutes the present invention.

As a storage medium for supplying the program code, for example, a floppy disk, hard disk, optical disk, magneto-optical disk, CD-ROM, C
DR, magnetic tape, nonvolatile memory card, RO
M, EEPROM and the like can be used.

When the computer executes the readout program code, not only the functions of the above-described embodiment are realized, but also the OS (Operating System) running on the computer based on the instruction of the program code. ) And the like perform part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

Further, after the program code read from the storage medium is written into the memory provided in the function expansion board inserted into the computer or the function expansion unit connected to the computer, the program code is read based on the instruction of the program code. , The CPU provided in the function expansion board or the function expansion unit performs a part or all of the actual processing,
It goes without saying that a case where the function of the above-described embodiment is realized by the processing is also included.

The present invention may be applied to a system composed of a plurality of devices or an apparatus composed of one device. Needless to say, the present invention can be applied to a case where the present invention is achieved by supplying a program to a system or an apparatus. In this case, by reading a storage medium storing a program represented by software for achieving the present invention into the system or the device, the system or the device can enjoy the effects of the present invention.

Further, by reading and reading a program represented by software for achieving the present invention from a database on a network by a communication program, the system or apparatus can be
It is possible to enjoy the effects of the present invention.

[0176]

As described above, the image forming apparatus of the present invention has an effect that the user can arbitrarily select the random number addition processing for correcting the gradation jump for each image area.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of an image forming apparatus according to an embodiment of the present invention.

FIG. 2A is an image forming apparatus according to an embodiment of the present invention.
FIG. 4 is a block diagram of an image processing unit 36, a controller unit 37, and a peripheral controlled unit.

FIG. 2B is an image forming apparatus according to an embodiment of the present invention.
FIG. 4 is a block diagram of an image processing unit 36, a controller unit 37, and a peripheral controlled unit.

FIG. 3 is a block diagram of a random number addition processing unit 180.

FIG. 4 is a random number generation unit 21 in a random number addition processing unit 180;
0 is a block diagram of FIG.

FIG. 5 is a block diagram of a random number maximum value calculation unit 220 in the random number addition processing unit 180.

6 is a block diagram of a random number addition amount calculation unit 230 in the random number addition processing unit 180. FIG.

FIG. 7 is a block diagram of a random number addition amount selection unit 240 in the random number addition processing unit 180.

8 is a random number adding unit 25 in the random number adding unit 180. FIG.
0 is a block diagram of FIG.

9 shows a selector 260 in the random number addition processing unit 180. FIG.
It is a block diagram of.

FIG. 10 is an explanatory diagram of control for changing a maximum value of random number data for each gradation in a random number addition amount calculation unit 230.

11 is an explanatory diagram of a random number addition process in a random number addition unit 250. FIG.

FIG. 12 is a diagram illustrating timings of generation of a select A signal and a select B signal in a random number adding unit 250.

FIG. 13A is a diagram (left half) showing a memory writing unit in the area generation circuit 160;

FIG. 13B is a diagram (right half) illustrating a memory writing unit in the area generation circuit 160;

FIG. 14 is a diagram illustrating a memory read unit in the area generation circuit 160;

FIG. 15A is a diagram showing an example of an address map when writing to a page memory. FIG. 4B is a diagram showing an example of a memory map at the time of memory reading.

FIG. 16 is a diagram showing the timing of a control signal when writing to a page memory.

FIG. 17 is a diagram showing the timing of every 16th line among the control signals when writing to the page memory.

FIG. 18 is a timing chart at the time of memory reading.

FIG. 19 is a flowchart illustrating a control flow according to the present embodiment.

FIG. 20 is a diagram illustrating an example of a table of an area decoding unit 310 according to the present invention.

21 is a diagram illustrating an example of a random number addition control table in an area decoding unit 310. FIG.

FIG. 22 is a diagram showing a configuration of a coloring circuit 165 according to the present invention.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H030 AA03 AD11 AD13 AD17 5B057 AA11 BA02 BA24 BA26 BA30 CA01 CA08 CA12 CA16 CB01 CB08 CB12 CB16 CC03 CE08 CE11 CE17 CH08 CH18 DA08 DA17 5C076 AA01 AA12 AA13 AA26 AA31 CA04 CA07 5C077 LL03 MP06 MP08 PP15 PP23 PP28 PP31 PP32 PP33 PP38 PP65 PQ08 RR11 SS05 TT06 5C079 HB03 LA06 LA10 LA31 LA36 LA40 LB12 MA11 NA02 PA02

Claims (12)

[Claims] An image reading step of reading an image on a document and converting the image into color image data; an area setting step of setting an area to which random number data is added in the color image data; An image processing method, comprising: a random number adding step of adding random number data only to data. 2. The method according to claim 1, wherein in the area setting step, whether or not to add random number data is set separately for a character area in the color image data and an area outside the character area. Image processing method. 3. An image reading step of reading an image on a document and converting the image into color image data, an adding step of adding a gradation image to the color image data, and a step of adding a gradation image to the color image data in the adding step. A random number data adding step of adding random number data to the image data of the partial area. 4. The method according to claim 1, wherein the random number data adding step includes a setting step of setting whether to add random number data separately for a character area in the color image data and an area outside the character area. The image processing method according to claim 3. 5. Image reading means for reading an image on a document and converting the image into color image data; area setting means for setting an area to which random number data is added in the color image data; An image processing apparatus, comprising: random number adding means for adding random number data only to data. 6. The apparatus according to claim 5, wherein the area setting means sets whether to add random number data separately for a character area in the color image data and for an area outside the character area. Image processing device. 7. An image reading means for reading an image on a document and converting the image into color image data, an adding means for adding a gradation image to the color image data, and an image reading means for adding a gradation image to the color image data. An image processing apparatus comprising: random number data adding means for adding random number data to image data of a partial area. 8. The method according to claim 1, wherein the random number data adding means includes setting means for setting whether to add random number data separately for a character area in the color image data and for an area outside the character area. The image processing device according to claim 7. 9. An image processing apparatus according to claim 8, wherein said random number data adding means includes an LUT for determining whether to add random number data for each partial area in said color image data. 10. An image processing apparatus according to claim 9, wherein said LUT is included in coloring means for determining coloring for each partial area in said color image data. 11. A storage medium storing a computer program for processing color image data read from a document, wherein the computer program stores a partial area in the color image data to which random number data is added. A storage medium comprising: a code of an area setting step to be set; and a code of a random number adding step of adding random number data only to the color image data in the set area. 12. A storage medium storing a computer program for processing an image obtained by synthesizing a gradation image with color image data read from an original, wherein the computer program stores the color image data to which the gradation image is added. And a code for adding random number data to the image data of the partial area.