JPH09200449A - Image processor and its method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform a copy process corresponding to document image characteristics at a high speed by making a prescan when a carriage is moved in the opposite direction from a scanning direction to copy a document. SOLUTION: When the carriage 314 of a read part 352 is moved in a process judgement scan direction (b), what is called a prescan of the document 350 is made and variables of respective parts which perform image formation are set according to the obtained image characteristics. Then when the carriage 314 moves in the document copy scanning direction (a), what is called a main scan is made to form an image, thereby enabling image formation corresponding to the image characteristics of the document while suppressing a decrease in processing speed.

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 a method thereof, for example, an image processing apparatus having an automatic document feeder and a method thereof.

[0002]

2. Description of the Related Art FIG. 12 shows a conventional automatic document feeder (A).
FIG. 3 is a cross-sectional view showing a schematic configuration of a reader unit in the DF) 302 and the image processing device 361. In the ADF 302, a plurality of originals 402 are placed on an original placing table 401, and a half-moon shaped feeding roller 403 and a conveying roller A4.
04, the conveyance roller B405, the conveyance roller C406, and the conveyance roller D407, the sheet is conveyed to the endless belt 408. The endless belt 408 is driven by a belt driving roller 409, and the original 402 is placed on the original table glass 30.
Convey to 1. After that, the sheet is again conveyed onto the document placing table 401 by the conveying roller E410 and the conveying roller F411.

In the reader unit 361, 101 is a CCD. In the present embodiment, the CCD 101 is a color sensor, and 311 is a substrate on which the CCD 101 is mounted. Reference numerals 303 and 304 denote light sources (halogen lamps or fluorescent lamps) for illuminating the original, and 305 and 306 denote light sources
Reflector for collecting the light of 03, 304 on the original, 307-3
Reference numeral 09 is a mirror, and 310 is a lens that collects reflected light or projection light from the document on the CCD 101. And 31
4 is a halogen lamp 303, 304 and a reflector 305, 3
A carriage 315 for accommodating the mirror 06 and the mirror 307 is a carriage for accommodating the mirrors 308 and 309. The carriage 314 has a speed V, and the carriage 315 has a speed V.
At / 2, the CCD 101 is mechanically moved in the direction perpendicular to the electrical scanning (main scanning) direction to scan (sub-scan) the entire surface of the document.

Next, FIG. 13 shows the configuration of a digital color copying machine provided with the above-mentioned ADF 302 and reader section 361.

The ADF 302 sequentially conveys a plurality of originals onto the original platen glass 301. The reader unit 361 scans a document on the platen glass 301 and reads it as an image signal, and the printer unit 362 forms an image according to the image signal.

In the printer unit 362, the laser scanner 363 forms a latent image by irradiating the photosensitive drum 342 with laser light. In addition, the M image forming unit 317,
The C image forming unit 318, the Y image forming unit 319, and the K image forming unit 320 each independently develop the latent image on the photosensitive drum 342 to form a toner image for each color.

Recording paper 36 stored in cassette 340
5 is conveyed to the transfer drum 364. Image forming unit 31
The toner image of each color formed by 7 to 320 is the recording paper 3
After being transferred onto the sheet 65 and thermally fixed by the fixing drum 334, the sheet is discharged to the sheet discharge tray 335.

In such a conventional digital color copying machine, an original is scanned in order to grasp the original image characteristics before the original is scanned for actual copying operation. Hereinafter, this scanning operation is referred to as prescan. Based on the image signal read by this pre-scan, it is possible to perform image characteristic determination processing, such as determining whether the original image is monochrome or color. Then, for example, when it is determined that the document is black and white by the prescan, the K image forming unit 320 controls the image forming process using only the black toner,
It is possible to obtain the effect that the toner of another color is not consumed. That is, by determining the original image characteristics by prescanning, it is possible to perform appropriate image processing according to the determination result, and it is possible to obtain higher quality output.

[0009]

However, the conventional digital color copying machine described above has the following problems.

That is, if a prescan is performed when a plurality of originals are continuously copied by the ADF 302, one original is conveyed onto the original table glass 301 and then the reader unit 36.
The one carriage 314, 315 needs to reciprocate twice. Since this is performed for all of a plurality of originals, there is a problem in that the copy speed becomes significantly slower than in the case where the prescan is not performed, and the copy time becomes significantly long.

The present invention has been made to solve this problem, and when prescan is performed for optimum image processing, a reduction in processing speed is minimized as compared with the case where prescan is not performed. An object of the present invention is to provide an image processing device and an image processing method that can be suppressed as much as possible.

[0012]

As one means for achieving the above object, the image processing apparatus of the present invention has the following configuration.

That is, scanning means for scanning a document to read an image signal, determining means for determining the image characteristics of the document based on the image signal, and image processing for the image signal according to the determination result by the determining means. Image processing setting means for setting a method, and image forming means for forming an image by performing image processing on the image signal by the image processing method set by the image processing setting means. When the document is scanned in the first direction, the determining unit determines the image characteristics of the document, and when the scanning unit scans the document in the second direction, the image forming unit forms an image. It is characterized by doing.

For example, the first direction and the second direction in the scanning means are different from each other.

For example, the first direction in the scanning means is opposite to the second direction.

For example, the scanning means is characterized by alternately performing the scanning in the first direction and the scanning in the second direction.

For example, the determining means is characterized by determining the image density of the document as the image characteristic of the document.

For example, the determination means is characterized by determining color information of the document as an image characteristic of the document.

For example, the determination means is characterized by determining the color space range of the document as an image characteristic of the document.

Further, it is characterized in that the apparatus further comprises an original supply means for sequentially supplying a plurality of originals one by one, and the scanning means scans the original supplied by the original supply means.

For example, the scanning means uses a memory corresponding to a required delay amount for each line in order to read the image signal of the original by the 3-line CCD and correct the reading position between the lines of the 3-line CCD. Delaying means for performing a delay by switching the connection order of the memories between the scanning of the scanning means in the first direction and the scanning of the scanning direction in the second direction. And

For example, the scanning means is characterized in that the side opposite to the scanning start position at the time of image formation by the image forming means is set as a reference position.

For example, the scanning means is characterized in that both the scanning start position side and the scanning end position side at the time of image formation by the image forming means are reference positions.

For example, a reference density plate is provided at both of the reference positions.

Further, it is characterized by further comprising a correction means for correcting the density difference between the two reference density plates.

As one method for achieving the above-mentioned object, the image processing method of the present invention comprises the following steps.

That is, the first scanning step of scanning the original in the first direction to read the image signal, and the determining step of determining the image characteristics of the original based on the image signal read in the first scanning step. An image processing setting step of setting an image processing method for the image signal according to a determination result in the determination step; a second scanning step of scanning an original in a second direction to read the image signal; And an image forming step of forming an image by subjecting the image signal read in the second scanning step to image processing by the image processing method set in the image processing setting step.

For example, the first direction and the second direction are different from each other.

For example, the first direction is opposite to the second direction.

For example, the first scanning process and the second scanning process are alternately performed.

[0031]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to the present invention will be described below in detail with reference to the drawings.

<First Embodiment> ● Outline of Processing The image processing apparatus according to the present embodiment reads a plurality of originals placed one by one by an automatic document feeder (ADF) and makes a continuous copy operation. It is possible to
FIG. 2 shows a schematic configuration of the ADF and the reader unit of the image processing apparatus according to this embodiment, and the features thereof will be described.
In FIG. 2, 351 is an ADF and 352 is a reader unit. In the ADF 351, 401 is a document table, 40
2 is a plurality of originals placed, and 350 is one original conveyed on the original platen glass 301. The arrows in the figure indicate the document conveying direction.

In the present embodiment, the document 350 placed on the document table glass 301 of the reader unit 352 is optically scanned by the reading carriage (hereinafter, carriage) 314 to read the document image signal. In the figure, the position of the carriage 314 is the original reading start position, and this position is hereinafter referred to as the home position (HP) of the carriage 314. In addition, the arrow a in the reader unit 352
Indicates the scanning direction (moving direction of the carriage 314) at the time of copying a document, and the arrow b indicates the scanning direction at the time of processing determination described later. Further, the Δ marks shown in the reader portion 352 are provided for the sake of convenience to indicate the position of the carriage 314.

Next, the outline of the case where the copy processing of a plurality of originals is performed using the ADF in the image processing apparatus of the present embodiment having the above-mentioned configuration will be described.

First, the reading operation of the first original will be described. The document 350 is placed on the platen glass 301,
When a start button (not shown) is pressed or the next original is conveyed by the AFD, the carriage 314 roughly scans the original 350 from the left side to the right side (original copy scanning direction a), and the density / size of the original is changed. Judge image characteristics such as color space and presence / absence of color. That is, prescan is performed. Then, the carriage 314 is moved to the home position (HP
1), the carriage 314 is again scanned from left to right (main scan) to form an image based on the read image signal, thereby performing the copy operation. During the copy operation by the main scan, image processing is performed according to the determination result of the image characteristics obtained by the prescan.

Next, the reading operation of the second and subsequent originals will be described. If the original 350 is the second or later of the plurality of originals 402, first, the carriage 314 is stopped at the position (position ΔC) where the first copy processing is completed. Then, after the document 350 is placed on the document table glass 301 by the ADF 351, the carriage 314 is moved from right to left (processing determination scanning direction b) to read the document 350 roughly, thereby making the density / color space of the document 350.・
Determine the image characteristics such as the presence or absence of color. That is, prescan is performed. Then, the carriage 314 is scanned from left to right (main scan) to form an image based on the read image signal, so that the second and subsequent copying operations are performed. In this case, of course, in the copying operation by the main scan, the image processing is performed according to the determination result of the image characteristics obtained by the prescan.

As described above, the third copy,
The fourth copy and the above-described second and subsequent copies are sequentially performed.

The configuration of the image processing apparatus of this embodiment will be described below in detail with respect to the reader section and the printer section. Configuration of Reader Unit The detailed configuration of the reader unit 352 in the image processing apparatus of this embodiment will be described with reference to FIG.

In FIG. 3, reference numeral 101 is a CCD. The CCD 101 in this embodiment is a color sensor, and R
Even if the color filter of GB is inline on the 1-line CCD in the order of RGB, it can also be the 3-line CCD.
Then, each of the R, G, and B filters is connected to each CC.
It may be arranged for each D. Further, the filter may be on-chip, or the filter and the CCD may be separately configured. Reference numeral 311 is a substrate on which the CCD 101 is mounted. Reference numerals 303 and 304 denote light sources (halogen lamps or fluorescent lamps) that illuminate the document, reference numerals 305 and 306 denote reflectors that condense the light from the light sources 303 and 304 onto the document, and 307.
Numerals 309 are mirrors, and 310 is a lens for condensing reflected light or projection light from the document on the CCD 101. And
314 is a halogen lamp 303, 304 and a reflector 30
A carriage for accommodating 5,306 and a mirror 307, 3
Reference numeral 15 is a carriage that houses the mirrors 308 and 309. The carriage 314 is at a speed V and the carriage 315 is at a speed V / 2 by mechanically moving in a direction perpendicular to the electrical scanning (main scanning) direction of the CCD 101.
The entire surface of the document is scanned (sub-scan). Incidentally, the carriage 31
The movement of 4, 315 is controlled by a motor 316. Further, 313 is an I / F unit that interfaces with another IPU or the like, and 312 is an image processing unit that performs various image processes described below on the read image signal.
Based on the image signal output from the image processing unit 312,
Image formation is performed in a printer unit 353 described later. An operation unit 300 is provided with a display panel, a plurality of operation buttons, and the like, and allows the operator to give an arbitrary operation instruction and notify the operator of the state of the apparatus.

The reader unit 352 described above is the ADF 35.
Although it is pressed by 1, a mirror surface pressure plate may be attached instead of the ADF 351.

Next, FIG. 4 shows a detailed block configuration of the image processing unit 312, and the image processing in this embodiment will be described.

The original 350 on the original table glass 301 reflects the light from the light sources 303 and 304, and the reflected light is the CCD.
It is guided to 101 and converted into RGB electrical signals. Then, the electric signal (analog image signal) is used as the image processing unit 3.
At 12, the data is first input to the A / D conversion unit 102. A
In the A / D conversion unit 102, the analog image signal from the CCD 101 is sampled and held (S / H), the dark level is clamped to a reference potential, amplified to a predetermined amount, and then A / D converted to obtain, for example, RGB. Obtain each 8-bit digital signal. The processing in the A / D converter 102 is not limited to the above order.

Then, the RGB digital signals are subjected to shading correction and black correction in the shading section 103, and then input to the original detection section 104. In the document detection unit 104, since the reading positions between the lines are different in the CCD 101 of three lines, the delay amount for each line is adjusted according to the reading speed, and the signal timing is corrected so that the reading positions of the three lines are the same. Connection processing, MFT correction processing that changes the reading MTF depending on the reading speed and magnification, and original detection that recognizes the original size by scanning the original on the original platen glass 301 Perform processing.

The digital signal whose reading position timing and the like have been corrected by the original detection section 104 is subjected to the spectral characteristics of the CCD 101 and the light source 30 by the input masking section 105.
The spectral characteristics of 3, 304 and the reflectors 305, 306 are corrected. The output of the input masking unit 105 is the selector 10
6, the selector 106 can switch between the image signal from the input masking unit 105 and the external signal input via the external I / F unit 114 according to the control signal from the CPU 120.

The signal output from the selector 106 is L
It is input to the OG converter 107 and the background remover 115.
After the background image is removed from the signal input to the background removal unit 115, the black character determination unit 116 determines whether or not it is a black character.
To generate a black character signal.

On the other hand, in the LOG converter 107, color space compression processing, background removal processing, and LOG conversion processing are performed. That is, as the color space compression processing, it is determined whether the read image signal is within the range that can be reproduced by the printer unit 353. If it is included, the image signal is kept as it is. If not, the image signal is within the color reproduction range of the printer unit 353. Correct so that Then, a background removal process is performed, and the RGB signal is converted into a CMY signal by LOG conversion. Then, in order to correct the timing deviation with the black character signal generated by the black character determination unit 116, the delay unit 108 adjusts the timing of the output signal of the LOG conversion unit 107.

The two kinds of signals output from the black character determination unit 116 and the delay unit 108 are subjected to moiré removal in the moiré removal unit 109, and the scaling processing unit 110 performs scaling processing as necessary in the main scanning direction. Is applied. Then, in the UCR unit 111, CMY processed by the scaling processing unit 110
The signal is converted into a CMYK signal by generating a K component by UCR processing, and is then corrected by masking processing to a signal according to the output characteristics of the printer unit 353, and a black character signal generated by the black character determination unit 116. Are fed back to the CMYK signals.

The signal output from the UCR unit 111 is density-adjusted by the γ correction unit 112 and then smoothed or edge-processed by the filter unit 113 to be output as an LED drive signal in the printer unit 353 described later. It

Reference numeral 120 is a CPU, and ROM 121
The image processing unit 3 based on the control program stored in
Controls the operation of the entire 12 as a whole. 122 is R
The AM is used as a work area of the CPU 120.

Here, in FIG. 5, a printer section 35 described later is shown.
3 shows a configuration for generating an LED drive signal. The 8-bit multi-valued image signal processed as described above in the image processing unit 312 is converted into a binary signal by the binary conversion unit 201. The conversion method may be any method such as a dither method, an error diffusion method, or an improved error diffusion method. Configuration of Printer Unit The detailed configuration of the printer unit 353 in the image processing apparatus of this embodiment will be described with reference to FIG.

In FIG. 3, 317 is an M image forming unit and 3 is an image forming unit.
Reference numeral 18 is a C image forming unit, 319 is an M image forming unit, and 320 is a K image forming unit. Since the respective configurations are the same, the M image forming unit 317 will be described in detail, and the other image forming units will be described. Is omitted.

In the M image forming section 317, 342 is a photosensitive drum, and a latent image is formed on the surface thereof by light irradiation from the LED array 210. Reference numeral 321 denotes primary electricity, which charges the surface of the photosensitive drum 342 to a predetermined potential to prepare for latent image formation. An M developing device 322 develops the latent image on the photosensitive drum 342 to form a toner image. Note that the developing device 322 includes a sleeve 345 for applying a developing bias to develop. Reference numeral 323 denotes a transfer belt electricity, which discharges from the back surface of the transfer belt 333 to transfer the toner image on the photosensitive drum 342 to the transfer belt 3.
Transfer to a recording paper or the like on 33. In addition, in the printer unit 353 of the present embodiment, the cleaner unit is not provided because transfer efficiency is good, but of course, the cleaner unit may be mounted.

Next, the procedure for conveying the recording paper will be described. The recording papers stored in the cassettes 340 and 341 are supplied onto the transfer belt 333 by the paper feed rollers 336 and 337 one by one by the pickup rollers 339 and 338.
The supplied recording paper is charged by the adsorption charger 346. Reference numeral 348 denotes a transfer belt roller, which drives the transfer belt 333 and charges the recording paper by forming a pair with the adsorption charger 346 to adsorb the recording paper to the transfer belt 333. A paper edge sensor 347 detects the edge of the recording paper on the transfer belt 333. The detection signal of the paper leading edge sensor 347 is sent from the printer unit 353 to the reader unit 352, and the reader unit 352 sends the detection signal to the printer unit 3.
It is used as a sub-scanning synchronization signal when sending a video signal to 53.

After that, the recording paper is conveyed by the transfer belt 333, and toner images are formed on the surfaces of the image forming units 317 to 320 of the respective colors in the order of M, C, Y and K. The recording paper that has passed through the K image forming unit 320 is easily removed from the transfer belt 333 in order to facilitate its separation.
After the charge is removed at 9, the transfer belt 333 is separated.
Reference numeral 360 is a peeling charger, and the recording paper is a transfer belt 333.
Distortion of an image due to peeling discharge when separated from
The separated recording paper is charged by the pre-fixing chargers 361 and 362 in order to supplement the toner suction force and prevent the image from being disturbed, and then the toner image is thermally fixed by the fixing device 334, and then the recording paper is discharged to the discharge tray 335. Is discharged.

Next, LED driving in the printer unit 353 will be described.

The multi-valued CMYK signals generated by the image processing unit 312 shown in FIG.
A binary CMYK signal is converted by the binary converter 201 of the LED driver shown in FIG. Hereinafter, the detailed configuration of the LED drive unit in the present embodiment will be described.

In FIG. 5, CMYK converted to binary
The signal is adjusted by the delay units 202 to 205 based on the paper leading edge detection signal from the paper leading edge sensor 347 to adjust the difference in distance between the paper leading edge sensor 347 and the image forming units 317 to 320. This makes it possible to record each color at a predetermined position on the recording paper. LED drive units 206 to 209
Generates a signal for driving the LEDs 210 to 213 of each color. In addition, in the present embodiment, an example in which the image recording is performed by the LED has been described, but the image recording may be performed by generating an electrostatic image by laser light. Image Reading Process Hereinafter, the copy process of a plurality of originals using the ADF, which is a feature of this embodiment, will be described in detail.

In FIG. 2 described above, the ADF 351 is one of a plurality of originals 402 placed on the original placing table 401.
The sheet is conveyed in the illustrated feeding direction. A copy process is performed on one fed document 350 at the position (document reading position) shown in the figure. And when the copy is finished,
The original 350 is conveyed to the original placing table 401, and at the same time, the next original is conveyed to the original reading position.

In FIG. 2, the carriage 314 is normally H
It is located at the position indicated by P1 (home position), moves in the document copy scan direction a (forward direction) during reading scanning, reads an image from the reading start position A to the reading end position B, and once at the reading stop position C. Stop. Then, it moves in the process determination scan direction b (return direction), returns to the HP1 position, and stops.

The copy processing in this embodiment will be described in detail below with reference to the flowchart shown in FIG. The process shown in FIG. 1 is started by pressing a copy start button (not shown) on the operation unit 300.

First, in step S1, the carriage 3
14 is moved to HP1, CCD 101, light source 303,
Shading correction such as 304 is performed.

In the present embodiment, the reference density plate is arranged at a position that can be read when the carriage 314 is moved to HP1 or at a position at a predetermined distance from HP1. Therefore, the carriage 314 is moved to a position where the reference density plate can be read, the gain of the amplifier and the offset value of the clamp in the A / D unit are set, and the light source 30 is read.
3, 304 is turned off, or is turned on when the reference density plate has a black density, and the dark value is sampled in a memory (not shown) in the shading correction unit 103 according to the read value at that time to calculate the dark value. The shading correction value of is calculated.

Then, the light sources 303 and 304 are turned on to bring the carriage 3 to a position where the white density of the reference density plate can be read.
14 is moved to obtain the white shading correction value as in the dark time. In this way, the shading correction values for dark and white are set to the shading correction unit 10.
By setting it in the correction value setting memory No. 3, the shading correction unit 103 performs appropriate shading correction on the read image thereafter.

Then, the process proceeds to step S2 to confirm the copy mode. For example, by checking whether or not a document is set on the document table 401 of the ADF 351, it is determined that the document is set on the platen glass 301 by the operator (manually) when the document is not set. Then, the process proceeds to step S9. On the other hand, ADF351
Even if the original is set in step S9, if the copy processing is for the first sheet, the process proceeds to step S9. Otherwise, go to step S3.

In step S9, the carriage 314 is moved from HP1 in the document copy scan direction (forward direction a) in the same manner as in the prior art to perform prescanning, and the document is read to the right end. Then, the read image signal is input to each block for performing image characteristic determination, which will be described later. Then, in step S10, the carriage 314 moved to the right end is returned to HP1. In the meantime, a calculation for the image characteristic determination process (determination process in the black character determination unit 116 or the like) described later may be performed.

On the other hand, in step S3, since the original has already been copied, the carriage 314 is stopped at the rightmost position, that is, the reading stop position C shown in FIG. Then, when a paper feed signal is output from the CPU 120, the document 350 is fed from the ADF 351 and set at a predetermined position. Then, the CPU 120 uses the ADF3
An original setting end signal is received from 51.

When the document 350 is set at the predetermined position in this way, the process proceeds to step S4 and the carriage 35
1 is moved from the stop position C toward HP1. At this time, when the CCD 101 has a three-line configuration, the document copy scanning direction “a” and the process determination scanning direction “b” are different in the connection process performed in the document detection unit 104, and therefore, before the carriage 314 is moved toward HP1. Switch the contents of the connection process. The details of this connecting process will be described later.

While the carriage 314 is moving, the original 350 is roughly read, and in step S5, the image characteristics such as the density, color space, and presence / absence of color of the original are determined based on the obtained signal. This image characteristic determination processing will be described later. Then, the carriage 314 is returned to HP1 to prepare for scanning for copying. Then, in step S6, based on the determination result in step S5, the processing corresponding to each original is set in each processing unit in the subsequent stage. Then, in order to copy the document 350, the carriage 314 is moved from HP1 in the document copy scanning direction a. Here, when the document 350 is smaller than the entire surface of the document table glass 301 as shown in FIG.
The carriage 314 stops at the document reading stop position C,
When the original 350 is the same size or larger than the original platen glass 301, the carriage 314 moves to the right end of the original platen glass 301.

Then, in step S7, the ADF 351
It is determined whether or not there is a next original, and if there is a next original, the process returns to step S2. Thus, ADF3
By repeating the above processing until there are no unprocessed originals on 51, the multiple copy processing in this embodiment is executed. Then, if there is no next original in the ADF 351 (including the copy processing for only one sheet), step S8.
Then, the carriage 314 is returned from the stop position C to HP1. As a result, the copy process in this embodiment is completed. Image Characteristic Determination Process The image characteristic determination process shown in step S5 described above will be briefly described below.

In the present embodiment, the density determination processing of the original image is performed for the background removal in the LOG conversion section 107 and the background removal section 115 described above. Hereinafter, the density determination processing in this embodiment will be described.

In order to store the image signal obtained roughly during the process judgment scan (direction b), the CPU 120 executes R, G,
The B signals are interpolated and stored in the RAM 122 or a dedicated memory. The memory capacity required at this time is one line. For example, a document image of 400 DPI can be recorded at 100 DP.
It is read as about I, and after interpolating each signal of R, G, B, it is stored for one line. Then, after that, the CPU 120
Creates a histogram of the read color signal on the RAM 122. By repeating this operation at a predetermined cycle when scanning the original, the histogram of the entire surface of the original is completed. Then, based on this histogram, the background level (R
w, Gw, Bw). Then, the correction (background removal) based on the background level is performed as shown by the following equation.

R ′ = R + ((255−Rw) × (R × G ×
B)) ÷ (Rw × Gw × Bw) G ′ = G + ((255−Gw) × (R × G × B)) ÷ (Rw ×
Gw × Bw) B ′ = B + ((255−Bw) × (R × G × B)) ÷ (Rw ×
Gw × Bw) In the above equation, R, G and B are input signals of respective colors, R ′,
G ′ and B ′ are each color signal after correction. Although the case where the image signal is represented by 8 bits has been described in the present embodiment, it goes without saying that the constant “255” in the above equation changes depending on the number of bits representing the image signal. .

Next, the color space compression processing in the LOG conversion unit 107 described above will be described. The color space compression processing according to the present embodiment is similar to the density determination processing described above,
The image signal input to the memory (not shown) is sampled and converted into L *, u *, v *, and a vector PX for the primary color P reproducible in the printer is obtained. Then, by the RGB signals of all the sampled input images, L
In the * u * v * uniform color space, a point X that is farthest from the printer primary color P in the monitor primary color M direction is obtained, and well-known color space compression processing is performed. If there is no color existing between the printer primary color P and the monitor primary color M, color space compression is not applied to the image.

The presence / absence of color (color determination) in this embodiment is performed by the black character determination unit 116. For example, the number of dots in the color portion within one line of the input image data is counted. When the count value exceeds a predetermined value, it is determined that the image is a color image, and for example, a color image is formed by four colors of CMYK and output. of course,. When it is determined that the image is a monochrome image, image formation and output in K1 color are performed.

Next, as described in step S4 above,
The joint correction switching processing in this embodiment will be described with reference to FIGS. 6 and 7. Below, CCD1
A case where 01 is a 3-line sensor will be described.

FIG. 6 is a diagram showing that the image positions read by the CCD 101 at the same timing are different for each line. In FIG. 6, 1011 and 1 on the CCD 101
012 and 1013 are line sensors. According to the figure, in the case of a document copy scan (scanning in the direction a), C
The bottom line 1013 of the CD 101 will read the original 350 first. Therefore, in order to read the same position on three lines, the bottom line 1013 and the center line 101
2, the image signal read in
It is necessary to delay the image signal read at 1. When this delay is realized by using a memory, the delay amount becomes maximum in the image signal read by the bottom line 1013, and therefore the bottom line 1013 requires the maximum memory capacity.

On the other hand, in the case of the processing determination scan (scanning in the direction b), the reading direction is opposite to that of the original copy scan, and therefore the uppermost line 1011 of the CCD 101 is the original 3
50 will be read first. Therefore, the order of the delay amount for each line is reversed, and the maximum memory capacity is required in the uppermost line 1011.

FIG. 7 shows a configuration example of the delay switching circuit for realizing the above-mentioned delay processing. That is, the configuration shown in FIG. 7 is provided in the document detection unit 104 that executes the joining process.
In FIG. 7, 71 is the uppermost line 101 of the CCD 101.
1 is a delay circuit that applies a delay process to the image signal read by 1 and similarly 72 is a central line 1012.
, And 73 is a delay circuit for the bottom line 1013. The size of the delay memory provided in each of the delay circuits 71, 72, 73 is 71 <72 <
The order is 73. Then, at the time of document copy scanning, the switches 74 and 75 are connected to the A and D ends, respectively, and the switches 76 and 77 are connected to the E and H ends, respectively. On the other hand, at the time of the processing judgment scan, the switches 74 and 75 are connected to the B and C ends, respectively, and the switches 76 and 77 are set to F and
Connect to G end.

If the CCD 101 is an in-line sensor, it is not necessary to perform such switching.

As described above, according to the present embodiment, it is possible to perform the copying process accompanied by the pre-scan by only one reciprocating movement of the carriage, and it is expected that the processing speed in the copying process of a plurality of originals will be greatly improved.

<Second Embodiment> The second embodiment according to the present invention will be described below.

The configuration of the image processing apparatus according to the second embodiment is the same as that of the above-described first embodiment, and the description thereof will be omitted. The second embodiment is characterized in that the home position of the carriage 314 is provided on the reading end position side when copying a document. The document image reading operation in the second embodiment will be described below with reference to FIGS. 8 and 9.

In FIG. 8, HP2 in the reader unit 352 is
Is the home position of the carriage 314 in the second embodiment.

The copy processing in the second embodiment will be described in detail below with reference to the flowchart shown in FIG. The process shown in FIG. 9 is started by pressing a copy start button (not shown) on the operation unit 300.

First, in step S201, the carriage 314 is moved to HP2 to move the CCD 101 and the light source 30.
Shading correction such as 3,304 is performed.

In the second embodiment, the reference density plate is arranged at a position that can be read exactly when the carriage 314 is moved to HP2, or at a position at a predetermined distance from HP2. Therefore, the carriage 314 is moved to a position where the reference density plate can be read, the gain of the amplifier and the offset value of the clamp in the A / D unit are set, and the light source 30 is read.
3, 304 is turned off, or is turned on when the reference density plate has a black density, and the dark value is sampled in a memory (not shown) in the shading correction unit 103 according to the read value at that time to calculate the dark value. The shading correction value of is calculated.

Then, the light sources 303 and 304 are turned on to bring the carriage 3 to a position where the white density of the reference density plate can be read.
14 is moved to obtain the white shading correction value as in the dark time. In this way, the shading correction values for dark and white are set to the shading correction unit 10.
By setting it in the correction value setting memory No. 3, the shading correction unit 103 performs appropriate shading correction on the read image thereafter.

Then, the process proceeds to step S202, and it is confirmed whether or not the copy mode in the second embodiment is confirmed, that is, whether or not the document image characteristic is automatically determined (automatic determination). The automatic determination is set in advance by the operation unit 300. When the automatic determination is not performed, the process proceeds to step S209, and otherwise, the process proceeds to step S2.
Go to 03.

In step S209, the carriage 314 is returned from HP2 to the original reading start position A, and in step S210, the carriage 314 is moved from the original reading start position A to HP2 in the original copy scanning direction a to perform normal copy processing. .

On the other hand, in step S203, the carriage 314 is stopped at HP2. And the CPU 120
When a paper feed signal is output from ADF 351, document 350 is fed from ADF 351 and set at a predetermined position. Then, the CPU 120 receives the document setting end signal from the ADF 351. If the document 350 is manually set without using the ADF 351, step S2 is performed.
The processing of 03 is through.

When the document 350 is set at a predetermined position,
The process proceeds to step S204, and the carriage 351 is set to H level.
It moves from P2 toward the reading start position A. At this time,
In the case where the CCD 101 has a three-line configuration, the connection process performed by the document detection unit 104 is different between the document copy scan direction a and the process determination scan direction b.
Before moving the carriage 314 toward the position A, the content of the connecting process is switched. The details of this connection processing are the same as those in the above-described first embodiment.

Then, while the carriage 314 is moving, the original 350 is roughly read, and in step S205, the image characteristics such as the density, color space, and the presence / absence of color of the original 350 are based on the obtained signals as in the first embodiment described above. Make the same judgment. Then, in step S206, step S205
On the basis of the result of the determination, the processing setting according to each document is performed in each processing unit in the subsequent stage. Then, in order to copy the document 350, the carriage 314 is moved from the position A in the document copy scanning direction a. Here, when the original 350 is smaller than the entire surface of the original glass 301 as shown in FIG. 8, the carriage 314 stops at the original reading stop position C, but the original 350 does not move.
If the size is the same as or larger than 01, the carriage 31
4 moves to HP2.

Then, in step S207, the ADF3
It is determined whether there is a next original in 51, and if there is a next original, the process returns to step S202. in this way,
By repeating the above processing until there are no unprocessed originals on the ADF 351, the multiple copy processing in this embodiment is executed. Then, when there is no next original in the ADF 351 (including the copy processing for only one sheet), the process proceeds to step S208, and the carriage 314 is returned from the stop position C to HP2. As a result, the copy process in this embodiment is completed.

As described above, according to the second embodiment,
Even if the home position of the carriage is set to a position different from that of the first embodiment, it is possible to perform the copy processing accompanied by the pre-scan with only one reciprocating movement of the carriage, and particularly, the processing speed in the copy processing of a plurality of originals is significantly improved. I can hope.

Further, by providing the home position at a position where priority is given to the case where prescan is performed, copying with prescan can be performed faster than in the first embodiment.

<Third Embodiment> The third embodiment of the present invention will be described below.

The configuration of the image processing apparatus according to the third embodiment is the same as that of the above-described first embodiment, and the description thereof will be omitted. In the third embodiment, the home position of the carriage 314 is provided at the reading start position side and the end position side at the time of copying an original, and when the original image characteristics are automatically determined, the carriage is moved to the HP2 side and when the automatic determination is not performed. Is characterized by moving to the HP1 side. The document image reading operation in the second embodiment will be described below with reference to FIGS. 10 and 11.

In FIG. 10, the HP in the reader unit 352 is
1 and HP2 are the carriage 31 in the third embodiment.
4 home position.

The copy processing in the third embodiment will be described in detail below with reference to the flowchart shown in FIG. The process shown in FIG. 11 is started by pressing a copy start button (not shown) on the operation unit 300.

First, in step S301, it is confirmed whether or not the copy mode in the third embodiment is confirmed, that is, whether or not the document image characteristic is automatically determined (automatic determination).
The automatic determination is set in advance by the operation unit 300. When the automatic determination is not performed, the process proceeds to step S309, and otherwise, the process proceeds to step S302.

In step S309, since the original image characteristic is not automatically determined, it is not necessary to perform the scan for image characteristic determination. Therefore, the carriage 314 is set to H
Moving to P1, shading correction of the CCD 101, the light sources 303, 304, etc. is performed. In the third embodiment, the first reference density plate is arranged at a position that can be read exactly when the carriage 314 is moved to HP1 or at a position at a predetermined distance from HP1. Therefore, the carriage 31
4 to the position where the first reference density plate can be read,
By setting the gain of the amplifier and the offset value of the clamp in the / D section, the light sources 303 and 304 are turned off, or turned on when the reference density plate has a black density, and the dark value is shaded by the read value at that time. A dark shading correction value is obtained by sampling and calculating in a memory (not shown) in the unit 103.

Then, the light sources 303 and 304 are turned on, the carriage 314 is moved to a position where the white density of the first reference density plate can be read, and the white shading correction value is obtained as in the dark time. In this way, by setting the dark and white shading correction values in the correction value setting memory of the shading correction unit 103,
Subsequent read images are subjected to appropriate shading correction in the shading correction unit 103.

Then, in step S310, the CPU
When the paper feed signal is output from 120, the ADF3
A document 350 is fed from 51 and set at a predetermined position. Then, the CPU 120 receives the document setting end signal from the ADF 351. The document 350 is ADF351
When the manual setting is performed without using, the process of step S310 is through.

When the document 350 is set at a predetermined position, the process proceeds to step S311, and the carriage 351 is set to HP.
By moving from 1 to the reading end position B, normal copy processing is performed. Then, in step S312, the carriage 314 is set to H in preparation for the next copy processing.
Return to P1.

Then, in step S313, the ADF3
It is determined whether there is a next original in 51, and if there is a next original, the process returns to step S310. On the other hand, ADF
If there is no next original in 351 (including the copy processing for only one sheet), the processing is ended as it is.

On the other hand, when the image characteristic automatic determination is performed, the carriage 314 is moved to HP2 in step S302, and shading correction of the CCD 101 and the light sources 303 and 304 is performed. In the third embodiment, the second reference density plate is arranged at a position that can be read when the carriage 314 is moved to HP2 or at a position at a predetermined distance from HP2. Therefore, the carriage 314 is moved to a position where the second reference density plate can be read, the gain of the amplifier and the offset value of the clamp in the A / D unit are set, the light sources 303 and 304 are turned off, or the black density is set on the reference density plate. If there is, a dark shading correction value is obtained by sampling the dark value in a memory (not shown) in the shading correction unit 103 based on the read value at that time and calculating the dark value.

Then, the light sources 303 and 304 are turned on and the carriage 314 is moved to a position where the white density of the second reference density plate can be read, and the white shading correction value is obtained as in the dark time. In this way, by setting the dark and white shading correction values in the correction value setting memory of the shading correction unit 103,
Subsequent read images are subjected to appropriate shading correction in the shading correction unit 103.

Then, in step S303, the CPU
When the paper feed signal is output from 120, the ADF3
A document 350 is fed from 51 and set at a predetermined position. Then, the CPU 120 receives the document setting end signal from the ADF 351. The document 350 is ADF351
If the manual setting is performed without using, the process of step S303 is through.

When the document 350 is set at a predetermined position, the process proceeds to step S304, and the carriage 351 is set to HP.
Move from 2 to HP1. At this time, the CCD 10
When 1 has a three-line configuration, in the document copy scanning direction a and the process determination scanning direction b, the document detecting unit 104 is used.
Since the connecting process performed in 3 is different, the contents of the connecting process are switched before the carriage 314 is moved toward HP1. The details of this connection processing are the same as those in the above-described first embodiment. Then, while the carriage 314 is moving, the document 350 is roughly read, and step S3
At 05, the image characteristics such as the density of the original, the color space, and the presence / absence of color are determined based on the obtained image signal in the same manner as in the first embodiment described above.

Then, in step S306, step S
Based on the determination result in 305, the processing setting according to each document is performed in each processing unit in the subsequent stage. Then, in order to execute the copy of the document 350, the carriage 3
14 is moved from the position A in the document copy scanning direction a. Here, when the original 350 is smaller than the entire surface of the original table glass 301 as shown in FIG. 10, the carriage 314 is used.
Stops at the original reading stop position C, but if the original 350 is the same size or larger than the original table glass 301, the carriage 314 moves to HP2.

Then, in step S307, the ADF3
It is determined whether there is a next original in 51, and if there is a next original, the process returns to step S303. in this way,
By repeating the above processing until there are no unprocessed originals on the ADF 351, the multiple copy processing in this embodiment is executed. Then, when there is no next original in the ADF 351 (including the copy processing for only one sheet), the process proceeds to step S308, and the carriage 314 is returned from the stop position C to HP2. As a result, the copy process in this embodiment is completed.

In the third embodiment, as described above, two reference density plates for shading correction are installed on the home positions HP1 and HP2 on both sides.
In this way, when the reference density plates are installed on both sides, a density difference due to manufacturing variations occurs between the two reference density plates. Therefore, there is a problem that the copy image to be output differs depending on which reference density plate is used for shading correction. Therefore, it is necessary to correct the density difference between the reference density plates.

The density correction process between the reference density plates in the third embodiment will be described below. Basically, the average density value of the two reference density plates is calculated, and the difference value from the average density value is obtained for each of the reference density plates. Then, a correction coefficient is set for the measured value of each reference density plate so as to compensate for the difference. Further, the density value is not limited to the variation in the density of the reference density plate at the time of manufacturing, and the density value may change due to the contamination of the reference density plate. In this case, the density value may change extremely. is there. Therefore, the density values of the reference density plates after correction by the above method are compared, and if it is determined that the signal values are extremely different, the data of the reference density plate that is considered to be abnormal is converted into the predetermined data. Substitution is also effective.

The correction coefficient of this reference density plate is, for example, C
The shading unit 103 is calculated by the PU 120.
It is stored in a memory or the like (not shown).

As described above, according to the third embodiment,
Even if the home positions of the carriage are provided at two positions on the scanning start side and the scanning end side, it is possible to perform the copying process accompanied by the pre-scan by only one reciprocating movement of the carriage as in the above-described first embodiment, and particularly, a plurality of originals. It is expected that the processing speed in the copy processing will be greatly improved.

Further, since the home position becomes effective at two places, the flexibility suitable for each of the case of performing the copy processing in which the image characteristics by the prescan are added and the case of performing the copy processing without performing the prescan. It is possible to perform various scans, and in any case, the optimum processing speed can be obtained.

<Other Embodiments> Even when the present invention is applied to a system including a plurality of devices (for example, host computer, interface device, reader, printer, etc.), a device including one device (for example, , A copying machine, a facsimile machine, etc.).

Further, an object of the present invention is to supply a storage medium having a program code of software for realizing the functions of the above-described embodiments to a system or apparatus, and to supply the computer (or CPU or MPU of the system or apparatus).
) Can be achieved by reading and executing the program code stored in the storage medium.

In this case, the program code itself read from the storage medium realizes the function of the above-described embodiment, 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, ROM
Etc. can be used.

Further, not only the functions of the above-described embodiment are realized by executing the program code read by the computer, but also the OS or the like running on the computer is actually executed based on the instruction of the program code. It goes without saying that a case where a part or all of the processing of (1) is performed and the functions of the above-described embodiments are realized by the processing is also included.

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

[0123]

As described above, according to the present invention, the so-called prescan is performed when the carriage is moved in the direction opposite to the scanning direction for performing the copy processing of the document, so that the image characteristics of the document can be adjusted. The copy processing can be realized at high speed.

[0124]

[Brief description of drawings]

FIG. 1 is a flowchart showing copy processing according to an embodiment of the present invention.

FIG. 2 is a block diagram showing configurations of an ADF and a reader unit of the image processing apparatus according to the present embodiment.

FIG. 3 is a block diagram showing a configuration of a printer unit in the present embodiment.

FIG. 4 is a block diagram showing a detailed configuration of an image processing unit in the present embodiment.

FIG. 5 is a block diagram showing a configuration for generating an LED drive signal in the present embodiment.

FIG. 6 is a diagram for explaining a reading position by a CCD in the present embodiment.

FIG. 7 is a block diagram showing a configuration example of a delay switching circuit in the present embodiment.

FIG. 8 is a block diagram showing a configuration of an ADF and a reader unit in a second embodiment according to the present invention.

FIG. 9 is a flowchart showing copy processing according to the second embodiment of the present invention.

FIG. 10 is a block diagram showing configurations of an ADF and a reader unit according to a third embodiment of the present invention.

FIG. 11 is a flowchart showing copy processing according to the third embodiment of the present invention.

FIG. 12 is a block diagram showing a configuration of an ADF and a reader unit in a conventional image processing apparatus.

FIG. 13 is a diagram showing a configuration of a conventional digital color copying machine.

[Explanation of symbols]

 300 Operation part 301 Document platen glass 312 Image processing part 313 I / F part 314, 315 Carriage 351 Automatic document feeder (ADF) 352 Reader part 353 Printer part 350 Original HP1, HP2 Home position A Original reading start position B Original reading End position C Original reading stop position a Original copy scanning direction b Processing judgment scanning direction

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location H04N 1/21 H04N 1/04 103Z 1/60 1/40 D 1/407 101E 1/48 1 / 46 A (72) Inventor Hideyuki Tana 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Mitsuru Amimoto 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. ( 72) Inventor Shigeo Yamagata 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Yoshio Komaki 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (17)

[Claims] 1. A scanning unit for scanning an original to read an image signal, a determining unit for determining an image characteristic of the original based on the image signal, and an image processing for the image signal according to a determination result by the determining unit. Image processing setting means for setting a method, and image forming means for forming an image by performing image processing by the image processing method set by the image processing setting means on the image signal, and by the scanning means When the document is scanned in the first direction, the determining unit determines the image characteristics of the document, and when the scanning unit scans the document in the second direction, the image forming unit forms an image. An image processing device characterized by: 2. The image processing apparatus according to claim 1, wherein the first direction and the second direction in the scanning unit are directions different from each other. 3. The image processing apparatus according to claim 2, wherein the first direction in the scanning means is opposite to the second direction. 4. The image processing apparatus according to claim 3, wherein the scanning unit alternately performs the scanning in the first direction and the scanning in the second direction. 5. The image processing apparatus according to claim 1, wherein the determination unit determines the image density of the document as an image characteristic of the document. 6. The image processing apparatus according to claim 1, wherein the determination unit determines color information of the document as an image characteristic of the document. 7. The determination means determines the color space range of the document as an image characteristic of the document.
The image processing apparatus according to any one of the preceding claims. 8. An original supply means for sequentially supplying a plurality of originals one by one, and the scanning means scans the originals supplied by the original supply means. The image processing device described. 9. The scanning means uses a memory corresponding to a required delay amount for each line in order to read an image signal of a document by a 3-line CCD and correct a reading position between the lines of the 3-line CCD. Delaying means for delaying the connection of the memories is switched between the scanning of the scanning means in the first direction and the scanning of the scanning direction in the second direction. The image processing apparatus according to claim 1. 10. The image processing apparatus according to claim 1, wherein the scanning unit sets a side opposite to a scanning start position when the image is formed by the image forming unit as a reference position. 11. The scanning unit uses both the scanning start position side and the scanning end position side as reference positions when an image is formed by the image forming unit.
The image processing apparatus according to any one of the preceding claims. 12. The image processing apparatus according to claim 11, wherein reference density plates are provided at both of the reference positions. 13. The image processing apparatus according to claim 12, further comprising a correction unit that corrects a density difference between the two reference density plates. 14. A first scanning step of scanning a document in a first direction to read an image signal, and a determining step of determining image characteristics of the document based on the image signal read in the first scanning step. An image processing setting step of setting an image processing method for the image signal according to a determination result in the determination step; a second scanning step of scanning an original in a second direction to read the image signal; And an image forming step of forming an image by performing image processing by the image processing method set in the image processing setting step on the image signal read in the second scanning step. 15. The image processing method according to claim 14, wherein the first direction and the second direction are different from each other. 16. The image processing method according to claim 15, wherein the first direction is opposite to the second direction. 17. The image processing method according to claim 16, wherein the first scanning step and the second scanning step are alternately performed.