JPH10200748A - Image processing device - Google Patents

Abstract

(57) [Problem] To provide an image processing apparatus capable of creating characteristic correction data as expected with high reliability of data accuracy in a short time. A gradation pattern is generated by an internal pattern generation unit, and a gradation characteristic of the generated gradation pattern is corrected by a characteristic correction unit using characteristic correction data set in advance. The corrected gradation pattern is output by the printer unit, the output gradation pattern is input by the scanner unit, and the start position detection circuit 133 detects the start position of the gradation pattern from the input gradation pattern. The average value of each gradation is calculated by the average value calculation circuit 134 from the detected start position of the gradation pattern, and the characteristic correction for correcting the gradation characteristics is performed by the characteristic correction data creating unit 135 based on the obtained average value of each gradation. Data is created, and the tone characteristics of the image information input from the scanner unit are corrected using the created characteristic correction data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, reading an image of a document with a scanner, inputting image information, performing predetermined processing on the input image information, and converting the image information into an electrophotographic image. And an image processing apparatus, such as a digital copying machine, which outputs the image on paper by a laser printer.

[0002]

2. Description of the Related Art Generally, in an image processing apparatus such as a digital copying machine which handles image information, image information read from a document by a reading means such as a scanner and digitized is multi-valued and processed according to the purpose. And output from output means such as a laser printer. At this time, the desired result cannot be obtained without correction due to the characteristics of the scanner as the input means, the photoconductor and the laser optical system of the output means, and the like.

Therefore, as a method of correcting the gradation characteristics throughout the entire system, such as the characteristics of the scanner of the input means, the photosensitive member of the output means, and the characteristics of the laser optical system, a gradation test such as a test print is performed for each image processing apparatus. The output device outputs the data whose characteristics are known, and inputs the data from the input device. A characteristic correction table (characteristic correction data) for correcting the gradation characteristics is created from the obtained data, and the data is referred to. A method of correcting the gradation characteristic is generally used.

Here, when the output from the output means is read and input by the input means, the input image signal is read by a CPU (Central Processing Unit) for a line memory which is updated every certain time. (1) An image signal is read by interrupt processing from the unit).

[0005]

However, when an interrupt process from the CPU is used to read an image signal input from the input means, a control circuit is added for controlling the interrupt process. And control is troublesome. When actually performing the interrupt processing, it takes a long time to interrupt from the CPU, and furthermore, the speed of reading the data on the line memory is low.
For example, in the case of a copying machine capable of copying 40 sheets per minute, if interrupt processing is performed from the CPU and all data stored in the line memory is read,
If the copier is operating at 100% copying speed, the scanner of the copier may be 160
mm, and the number of readable gradations is limited to 2-3 gradations.

Therefore, a plurality of stages (for example, 16 or 3)
In order to make the scanner read a gradation pattern on which two gradations (such as two gradations) are printed and to generate gradation characteristic correction data, the operation speed of the scanner is reduced to 1/8 to 1/4. And the read amount of the line memory is also partially (1/20)
(The following data amount), and by shortening the data reading time, the gradation data read from the input means can be secured by the number of gradations.

However, even if the number of tones that can be read is secured as described above, it takes approximately 30 seconds to read and the number of read data is small, so that the density unevenness of the output means and the unevenness of the reading of the input means. However, there is a problem that the optical system of the input means is easily affected by dust and the like, and the reliability of calculation accuracy of calculation data is low.

Therefore, the present invention provides a method for generating characteristic correction data for correcting the input and output characteristics of each aircraft throughout the entire system in a short time, with high reliability of data accuracy, and as expected. It is an object to provide an image processing device capable of creating data.

[0009]

An image processing apparatus according to the present invention performs predetermined processing on image information input from an input means, and then outputs the image information by an output means. And a first characteristic for correcting a gradation characteristic of the gradation pattern generated by the gradation pattern generating unit using first characteristic correction data stored in advance. Correction means, a gradation pattern output means for outputting the gradation pattern corrected by the first characteristic correction means using the output means, and a gradation pattern output from the gradation pattern output means to the input. Means for inputting a tone pattern using the means, an average value calculating circuit for calculating an average value of each tone based on the tone pattern input by the means for inputting the tone pattern, and the average value A characteristic correction data generating means for generating second characteristic correction data for correcting the gradation characteristic based on the average value of each gradation obtained by the output circuit; and a second characteristic correction data generating means for generating the second characteristic correction data. And a second characteristic correcting unit for correcting the gradation characteristic of the image information input by the input unit using the characteristic correction data.

An image processing apparatus according to the present invention, which performs a predetermined process on image information input from an input means and outputs the image information by an output means,
A gradation pattern generating means for generating a gradation pattern, and a gradation characteristic correcting means for correcting gradation characteristics of the gradation pattern generated by the gradation pattern generating means using first characteristic correction data stored in advance. 1 characteristic correction means and the first
A gradation pattern output means for outputting the gradation pattern corrected by the characteristic correction means using the output means, and a gradation pattern output means for inputting the gradation pattern output from the gradation pattern output means using the input means. Tone pattern input means, a start position detection circuit for detecting a start position of the tone pattern from an image signal of the tone pattern input by the tone pattern input means, and a tone detected by the start position detection circuit An average value calculating circuit for obtaining an average value of each gradation from the start position of the pattern, and a second value correcting circuit for correcting the gradation characteristics based on the average value of each gradation obtained by the average value calculating circuit.
Using the characteristic correction data creating means for creating the characteristic correction data and the second characteristic correction data created by the characteristic correction data creating means, the gradation characteristic of the image information input by the input means is corrected. Second characteristic correcting means.

Further, the image processing apparatus of the present invention digitizes the image information input from the input means, processes the digitized image information according to the purpose, and then outputs the image information by the output means. In the output, a gradation pattern generating means for generating a gradation pattern that changes stepwise, and first characteristic correction data stored in advance for the gradation pattern generated by the gradation pattern generating means. A first characteristic correction means for correcting the gradation characteristic using the first characteristic correction means; a gradation pattern output means for outputting the gradation pattern corrected by the first characteristic correction means using the output means; A tone pattern input means for inputting a tone pattern output from the pattern output means using the input means, and an image signal of the tone pattern input by the tone pattern input means. A start position detection circuit for detecting a start position of the gradation pattern, and an average value for obtaining an average value of each gradation by sampling each gradation from the start position of the gradation pattern detected by the start position detection circuit. A second calculating circuit for correcting the tone characteristics based on the average value of each tone obtained by the average value calculating circuit.
Characteristic correction data generating means for generating the characteristic correction data for each gradation, and the gradation of the image information input by the input means using the second characteristic correction data generated by the characteristic correction data generating means. A second characteristic correction unit for correcting the characteristic.

Further, the image processing apparatus of the present invention digitizes the image information input from the input means, processes the digitized image information according to the purpose, and outputs the image information by the output means. In the output, a gradation pattern generating means for generating a gradation pattern that changes stepwise, and first characteristic correction data stored in advance for the gradation pattern generated by the gradation pattern generating means. A first characteristic correction means for correcting the gradation characteristic using the first characteristic correction means; a gradation pattern output means for outputting the gradation pattern corrected by the first characteristic correction means using the output means; A tone pattern input means for inputting a tone pattern output from the pattern output means using the input means, and an image signal of the tone pattern input by the tone pattern input means. A start position detection circuit for detecting the start position of the gradation pattern in real time, and an average value of each gradation within a preset range is obtained from the start position of the gradation pattern detected by the start position detection circuit. An average value calculation circuit, a register for holding the average value of each tone obtained by the average value calculation circuit, and an average value of each tone held in this register using a CPU (Central Processing Unit). Reading means for reading, and interpolating means for increasing the number of data by interpolation from the average value of each gradation read out by the reading means using a CPU such that the number of data of the average value becomes a preset data number. From the gradation characteristics indicated by the data increased by the interpolation means, a second characteristic complement for correcting the gradation characteristics using the CPU is provided. Characteristic correction data generating means for generating data for each gradation, storage means for storing the second characteristic correction data generated by the characteristic correction data generating means, and second characteristic correction data stored in the storage means A second step of correcting the gradation characteristics of the image information input by the input means by setting of the CPU based on the data;
Characteristic correction means.

Further, the image processing apparatus of the present invention reads an image of a document by reading means, inputs image information, performs predetermined processing on the input image information, and forms the image information into an image. In an image processing apparatus for forming and outputting an image on a medium on which an image is to be formed, a gradation pattern generating means for generating a gradation pattern that changes stepwise, and a gradation pattern generated by the gradation pattern generating means ,
A first characteristic correction unit for correcting gradation characteristics using first characteristic correction data stored in advance, and a gradation pattern corrected by the first characteristic correction unit is received by the image forming unit. Gradation pattern output means for forming and outputting on the image forming medium, gradation pattern input means for inputting the gradation pattern on the image forming medium output by the gradation pattern output means using the reading means, A start position detection circuit for detecting a start position of the gradation pattern from an image signal of the gradation pattern input by the gradation pattern input means;
An average value calculation circuit for calculating an average value of each gradation from the start position of the gradation pattern detected by the start position detection circuit, and a gradation value based on the average value of each gradation calculated by the average value calculation circuit. A characteristic correction data generating unit for generating second characteristic correction data for correcting characteristics; and an image input by the reading unit using the second characteristic correction data generated by the characteristic correction data generating unit. A second characteristic correcting means for correcting the gradation characteristic of the information.

Further, the image processing apparatus of the present invention comprises: a latent image forming means for forming a latent image based on image information on an image carrier;
Developing means for developing the latent image on the image carrier formed by the latent image forming means with a developer; and developing a developer image on the image carrier developed by the developing means on an image forming medium. Transfer means for transferring, gradation pattern generation means for generating a gradation pattern that changes stepwise, and first characteristic correction stored in advance for the gradation pattern generated by the gradation pattern generation means A first characteristic correction unit that corrects a gradation characteristic using data, and a gradation pattern corrected by the first characteristic correction unit.
And a gradation pattern output means for forming and outputting on the image forming medium using the transfer means, and a reading means for reading and inputting the gradation pattern on the image forming medium output by the gradation pattern output means, A start position detection circuit for detecting the start position of the gradation pattern from the image signal of the gradation pattern input by the reading means, and a start position of the gradation pattern detected by the start position detection circuit, for each gradation. An average value calculating circuit for obtaining an average value, and characteristic correction data generating means for generating second characteristic correction data for correcting the grayscale characteristic based on the average value of each gradation obtained by the average value calculating circuit. And second characteristic correction means for correcting the gradation characteristic of the image information using the second characteristic correction data created by the characteristic correction data creation means.

Further, the image processing apparatus of the present invention performs predetermined processing on image information input from an input means, and then outputs the image information by an output means.
A tone pattern generating means for generating a tone pattern, a tone pattern output means for outputting the tone pattern generated by the tone pattern generating means using the output means, and an output by the tone pattern output means Tone pattern input means for inputting the obtained tone pattern using the input means,
An average value calculating circuit for calculating an average value of each tone based on the tone pattern input by the tone pattern input means; and a tone characteristic based on the average value of each tone determined by the average value calculating circuit. Using the characteristic correction data generating means for generating characteristic correction data for correction and the characteristic correction data generated by the characteristic correction data generating means, correcting the gradation characteristic of the image information input by the input means. Characteristic correction means.

Further, the image processing apparatus of the present invention performs predetermined processing on image information input from the input means, and then outputs the image information by the output means.
A tone pattern generating means for generating a tone pattern, a tone pattern output means for outputting the tone pattern generated by the tone pattern generating means using the output means, and an output by the tone pattern output means Tone pattern input means for inputting the obtained tone pattern using the input means,
From a tone pattern image signal input by the tone pattern input means, a start position detection circuit for detecting a start position of the tone pattern, and a start position of the tone pattern detected by the start position detection circuit, An average value calculating circuit for calculating an average value of each gradation, and characteristic correction data generating means for generating characteristic correction data for correcting a gradation characteristic based on the average value of each gradation calculated by the average value calculating circuit. And characteristic correction means for correcting the gradation characteristic of the image information input by the input means using the characteristic correction data generated by the characteristic correction data generation means.

According to the present invention, the average value of each gradation is obtained from the reading of the gradation pattern by using a CPU as in the prior art.
In order to correct the input and output characteristics of each unit throughout the entire system, by performing processing from reading to calculation of the average value of each gradation by using a hardware circuit, instead of using interrupt processing by When the characteristic correction data is generated, the reliability of the data accuracy is high and the expected characteristic correction data can be generated in a short time.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an internal configuration of a digital copying machine as an example of an image processing apparatus according to the present embodiment. This digital copier, for example,
It is a complex type copier having three functions of copier, facsimile and printer.

In FIG. 1, reference numeral 10 denotes an apparatus main body, in which a scanner section 4 as input means and reading means and a printer section 6 as output means and image forming means are provided. .

On an upper surface of the apparatus main body 10, an original placing table 12 made of transparent glass on which an original D as an object to be read is placed is provided. An automatic document feeder 7 (hereinafter, abbreviated as ADF) for automatically feeding the document D onto the document table 12 is provided on the upper surface of the apparatus main body 10. The ADF 7 is provided so as to be openable and closable with respect to the document table 12, and also functions as a document holder for bringing the document D placed on the document table 12 into close contact with the document table 12.

The ADF 7 includes a document tray 8 on which a document D is set, an empty sensor 9 for detecting the presence or absence of a document, a pickup roller 14 for picking up the documents D one by one from the document tray 8, and a feeder for transporting the picked-up document D. Paper roller 1
5. A pair of aligning rollers for aligning the leading edge of the document D
6. A transport belt 18 is provided so as to cover almost the entire surface of the document table 12. Then, the document tray 8
The plurality of originals D set upward are taken out in order from the bottom page, that is, the last page, are aligned by the aligning roller pair 16, and then are transported on the original placing table 12 by the transport belt 18. It is transported to a predetermined position.

In the ADF 7, a reversing roller 20, a non-reversing sensor 21, a flapper 22, and a paper discharge roller 23 are disposed at an end opposite to the aligning roller pair 16 with the transport belt 18 interposed therebetween. . The document D whose image information has been read by the scanner unit 4 is sent out from the document table 12 by the transport belt 18 and
0, flapper 21 and discharge roller 22
The document is discharged onto the document discharge unit 24 on the upper surface of the DF 7. When reading the back side of the document D, the document D transported by the transport belt 18 is switched by switching the flapper 22.
After being reversed by the reversing roller 20, the sheet is again sent to a predetermined position on the document table 12 by the transport belt 18.

The scanner unit 4 provided in the apparatus main body 10
Has an exposure lamp 25 as a light source for illuminating the original D placed on the original placing table 12, and a first mirror 26 for reflecting light reflected from the original D in a predetermined direction. The exposure lamp 25 and the first mirror 26 are mounted on a first carriage 27 disposed below the document table 12. The first carriage 27 is disposed so as to be movable in parallel with the document table 12, and is driven by a drive motor via a toothed belt (not shown) or the like.
Is reciprocated below.

Below the document table 12, the document table 1
A second carriage 28 movable parallel to the second carriage 2 is provided. The second carriage 28 has a first mirror 26
The second and third mirrors 30, 31 for sequentially reflecting the light reflected from the document D reflected by the document D are mounted at right angles to each other. The second carriage 28 is driven by the first carriage 27 by a toothed belt or the like that drives the first carriage 27, and the document table is moved at a half speed with respect to the first carriage. 12 are moved in parallel.

An image forming lens 32 for converging the light reflected from the third mirror 31 on the second carriage 28 and a reflected light condensed by the image forming lens 32 are provided below the document table 12. CC as photoelectric conversion means for performing photoelectric conversion
A D-shaped line sensor 34 is provided. The imaging lens 32 is movably disposed via a drive mechanism in a plane including the optical axis of the light reflected by the third mirror 31,
By moving itself, the reflected light is imaged at a desired magnification.
Then, the line sensor 34 photoelectrically converts the incident reflected light and outputs an electric signal corresponding to the read original D.

On the other hand, the printer section 6 includes a laser exposure device 40 as a latent image forming means. The laser exposure device 40 includes a semiconductor laser oscillator 41 as a light source, a polygon mirror 36 as a scanning member for continuously deflecting the laser light emitted from the semiconductor laser oscillator 41, and a predetermined rotation speed which will be described later. A polygon motor 37 as a scanning motor that is driven to rotate by an optical system, and an optical system 42 that deflects laser light from the polygon mirror 36 and guides the laser light to a photosensitive drum 44 described later. The laser exposure apparatus 40 having such a configuration is fixedly supported by a support frame (not shown) of the apparatus main body 10.

The semiconductor laser oscillator 41 includes a scanner unit 4
ON / OFF control is performed in accordance with image information of the document D read by the scanner or facsimile transmission / reception document information, and the laser light is transmitted to the polygon mirror 36 and the optical system 4.
The electrostatic latent image is formed on the peripheral surface of the photoconductor drum 44 by exposing and scanning the peripheral surface of the photoconductor drum 44 by being directed to the photoconductor drum 44 via the photoconductor drum 44.

The printer section 6 has a rotatable photosensitive drum 44 as an image carrier disposed substantially at the center of the apparatus main body 10. The peripheral surface of the photosensitive drum 44 is Is exposed and scanned by the laser light from the laser beam, and a desired electrostatic latent image is formed. Around the photoconductor drum 44, a charging charger 45 for charging the peripheral surface of the photoconductor drum 44 to a predetermined charge, and supplies a toner as a developer to an electrostatic latent image formed on the photoconductor drum 44 A developing unit 46 as a developing unit for developing the image at a desired image density; a separating charger 47 for separating the sheet P as an image forming medium supplied from a sheet feeding cassette to be described later from the photosensitive drum 44; A transfer charger 48 for transferring the toner image formed on the photosensitive drum 44 to the sheet P;
A peeling claw 49 for peeling the sheet P from the peripheral surface of the photosensitive drum 44; a cleaning device 50 for cleaning the toner remaining on the peripheral surface of the photosensitive drum 44;
And a static eliminator 51 for neutralizing the peripheral surface of the photosensitive drum 44
Are arranged in order.

In the lower portion of the apparatus main body 10, an upper paper cassette 52, a middle paper cassette 53, and a lower paper cassette 54 which can be pulled out from the apparatus body 10 are arranged in a stacked state. Sheets P of different sizes are loaded in 52 to 54. A large-capacity feeder 55 is provided beside these paper cassettes 52 to 54. The large-capacity feeder 55 is provided with a sheet P of a frequently used size, for example, about 300 sheets of A4 size paper P.
0 sheets are stored. Above the large-capacity feeder 55, a paper feed cassette 57 also serving as a manual feed tray 56 is detachably mounted.

In the apparatus main body 10, each paper feed cassette 52 is provided.
To the photosensitive drum 44 from the large-capacity feeder 55
A transfer path 58 that extends through a transfer section located between the transfer path and the transfer charger 48 is formed. At the end of the transfer path 58, a fixing device 60 having a fixing lamp 60a is provided. A discharge port 61 is formed on the side wall of the apparatus main body 10 facing the fixing device 60, and a single tray finisher 150 is attached to the discharge port 61.

In the vicinity of the upper sheet cassette 52, the middle sheet cassette 53, the lower sheet cassette 54, the sheet cassette 57 and the large capacity feeder 55, the sheet cassette 5
2 to 54, 57 or the large-capacity feeder 55
Pickup rollers 63 are provided to take out each sheet one by one. The transport path 58 is provided with a number of paper feed roller pairs 64 for transporting the sheet P taken out by the pickup roller 63 through the transport path 58.

In the transport path 58, a pair of registration rollers 65 is provided upstream of the photosensitive drum 44. The registration roller pair 65 corrects the inclination of the taken out paper P, aligns the leading end of the toner image on the photosensitive drum 44 with the leading end of the paper P, and has the same speed as the moving speed of the peripheral surface of the photosensitive drum 44. The sheet P is supplied to the transfer unit at a speed. A pre-alignment sensor 66 that detects the arrival of the sheet P is provided before the pair of registration rollers 65, that is, on the side of the sheet feeding roller 64.
Is provided.

The paper P taken out one by one from each of the paper feed cassettes 52 to 54 and 57 or the large-capacity feeder 55 by the pickup roller 63 is sent to the registration roller pair 65 by the paper feed roller pair 64. And the paper P
After the tip is aligned by the registration roller pair 65,
It is sent to the transfer unit.

In the transfer section, the developer image formed on the photosensitive drum 44, that is, the toner image is transferred onto the sheet P by the transfer charger 48. The paper P on which the toner image has been transferred is peeled off from the peripheral surface of the photosensitive drum 44 by the action of the peeling charger 47 and the peeling claw 49, and
Fixing device 6 via a transport belt 67 constituting a part of the fixing device 6
Transported to zero. Then, after the developer image is fused and fixed on the sheet P by the fixing device 60, the sheet P is discharged onto the finisher 201 through the discharge port 61 by the sheet feed roller pair 68 and the sheet discharge roller pair 69.

Below the conveying path 58, there is provided an automatic double-sided device 70 for reversing the sheet P having passed through the fixing device 60 and sending it again to the pair of registration rollers 65. Automatic duplex device 7
Reference numeral 0 denotes a temporary stacking unit 71 for temporarily stacking the sheets P, a reversing path 72 that branches off from the transport path 58 and reverses the sheet P that has passed through the fixing device 60 and guides the sheet P to the temporary stacking unit 71; The pickup roller 73 includes a pickup roller 73 that picks up the sheets P stacked on the sheet 71 one by one, and a paper feed roller 75 that supplies the picked-up sheets P to a pair of registration rollers 65 through a conveyance path 74. A distribution gate 76 for selectively distributing the paper P to the discharge port 61 or the reversing path 72 is provided at a branch portion between the transport path 58 and the reversing path 72.

When performing double-sided copying, the paper P that has passed through the fixing device 60 is guided to a reversing path 72 by a distribution gate 76, and is temporarily accumulated in a temporary accumulating section 71 in a reversed state. 73 and a pair of paper feed rollers 75, a pair of registration rollers 6
Sent to 5. Then, the paper P is transferred to the pair of registration rollers 65.
, And then sent to the transfer section again, where the toner image is transferred to the back surface of the paper P. Thereafter, the paper P is discharged to the finisher 201 via the transport path 58, the fixing device 60, and the paper discharge roller 69.

The finisher 201 is for stapling and storing the discharged partially structured documents in a unit. Each time one sheet of paper P to be stapled is discharged from the discharge port 61, it is brought closer to the side to be stapled by the guide bar 202 and aligned. When all of the paper P has been discharged, the paper holding arm 203 holds down the discharged paper P in a unit,
A stapler unit (not shown) performs stapling.

Thereafter, the guide bar 202 is lowered, and the stapled paper P is partially discharged from the finisher discharge tray 204 by the finisher discharge roller 204.
05. The amount by which the finisher discharge tray 205 is lowered is determined to some extent by the number of sheets P to be discharged, and decreases stepwise each time a part of the sheet P is discharged.
A guide bar 2022 for aligning the discharged paper P
Is located at such a height that it does not hit the already stapled paper P placed on the finisher discharge tray 205.

Further, the finisher discharge tray 154 is
In the sort mode, it is connected to a shift mechanism (not shown) that shifts every part (for example, in four directions of front, rear, left and right).

An operation panel 8 for inputting various copy conditions, a copy start command for starting a copy operation, and displaying an operation state, etc., is provided on an upper front portion of the apparatus main body 10.
0 (not shown) is provided.

FIG. 2 is a block diagram schematically showing a signal flow for electrical connection and control of the digital copying machine shown in FIG. In FIG. 2, the control system includes:
A main CPU 91 in the main control unit 90, a scanner CPU 100 in the scanner unit 4, and a printer CP in the printer unit 6.
It is composed of three CPUs (central processing unit) of U110.

The main CPU 91 is connected to the printer CPU 11
0 through the shared RAM 95, and the main CPU 91 issues an operation instruction to the printer C.
The PU 110 returns a status status.
The printer CPU 110 and the scanner CPU 100 perform serial communication, the printer CPU 110 issues an operation instruction, and the scanner CPU 100 returns a status.

The operation panel 80 includes various operation keys 81, a liquid crystal display section 82, and a panel CP to which these are connected.
It has U83 and is connected to the main CPU91. The main control unit 90 includes a main CPU 91, a ROM 92, a RAM
93, NVRAM 94, shared RAM 95, image processing unit 9
6, page memory control unit 97, page memory 98, printer controller 99, and printer font RO
M121.

The main CPU 91 controls the overall control. The ROM 92 stores a control program and the like. The RAM 93 temporarily stores data.

An NVRAM (Nonvolatile RAM) 94 is a non-volatile memory that is backed up by a battery (not shown) and retains stored data even when the power is turned off.

The shared RAM 95 is used for performing bidirectional communication between the main CPU 91 and the printer CPU 110. The page memory control section 97 stores and reads out image information from the page memory 98. The page memory 98 has an area in which image information for a plurality of pages can be stored, and is formed so that data obtained by compressing image information from the scanner unit 4 can be stored for each page.

The printer font ROM 121 stores font data corresponding to print data. The printer controller 99 converts print data from an external device 122 such as a personal computer into image data using font data stored in the printer font ROM 121 at a resolution corresponding to the data indicating the resolution given to the print data. It expands to.

The scanner unit 4 includes a scanner CPU 100 for controlling the entire system, a ROM 101 storing a control program and the like, a RAM 102 for storing data, a CCD driver 103 for driving the line sensor 34, an exposure lamp 25, and mirrors 26 and 27. , 28, and the like, and includes a scanning motor driver 104 that controls the rotation of the scanning motor that moves the scanning motor, and an image correction unit 105.

The image correction unit 105 converts an analog signal from the line sensor 34 into a digital signal, an A / D conversion circuit, and outputs from the line sensor 34 due to variations in the line sensor 34 or changes in ambient temperature. It is composed of a shading correction circuit for correcting a threshold level fluctuation with respect to a signal, a line memory for temporarily storing a shading-corrected digital signal from the shading correction circuit, and the like.

The printer section 6 includes a printer CPU 110 for overall control, a ROM 111 for storing control programs and the like, a RAM 112 for data storage, a laser driver 113 for driving the semiconductor laser oscillator 41, and a polygon motor for the laser exposure device 40. The charging, development, and transfer are performed using a polygon motor driver 114 that drives the printer 37, a conveyance control unit 115 that controls the conveyance of the sheet P by the conveyance path 58, a charging charger 45, a developing device 46, and a transfer charging device 48. It comprises a process control unit 116 for controlling the process, a fixing control unit 117 for controlling the fixing device 60, an option control unit 118 for controlling options, and the like.

The image processing section 96 and the page memory 9
8. The printer controller 99, the image correction unit 105, and the laser driver 113 are connected by an image data bus 120.

The image processing section 96 corrects the gradation characteristics (density characteristics) of the image information read by the scanner section 4. For example, as shown in FIG. Internal pattern generating section 131, internal pattern generating section 1 as gradation pattern generating means for generating a pattern
A data selection unit 132 for selecting and outputting either the gradation pattern generated from the scanner unit 31 or the image information input from the scanner unit 4; A start position detection circuit 133 composed of a hardware circuit for detecting a read start position of the image, and an average value of each gradation is calculated for each gradation from a read start position of the gradation pattern detected by the start position detection circuit 133. Average value calculation circuit 134 composed of a hardware circuit to be obtained, and characteristic correction data for creating characteristic correction data for correcting gradation characteristics based on the average value of each gradation calculated by average value calculation circuit 134 A characteristic correction data creating unit 135 as a creating unit, the characteristic correction data created by the characteristic correction data creating unit 135, and a preset Characteristic compensation data holding unit 136 as a storage means for storing characteristic correction data in a table,
A characteristic correction unit 137 as a characteristic correction unit that corrects the gradation based on the characteristic correction data stored in the characteristic correction data storage unit 136 for the image information selected by the data selection unit 132. .

The start position detecting circuit 133 is provided with a switch 138 for turning the operation on and off. The switch 138 controls the start position detecting circuit 133.
Is turned off, the average value calculation circuit 134 calculates the average value of each gradation without performing the process of detecting the start position of the gradation pattern by the start position detection circuit 133. ing.

Next, a specific configuration example of the start position detection circuit 133 and the average value calculation circuit 134 will be described.
FIG. 4 shows a specific circuit configuration example of the start position detection circuit 133. In FIG. 4, a sampling range control signal generator 141 includes a counter value 142 a output from the sub-scanning counter 142 and a main scanning counter 1.
From the counter value 143a output from the register 43 and the main scanning start / end parameter 144 stored in the register, a signal indicating whether or not the area is a sampling area in the main scanning direction, that is, a sampling section valid signal 141a.
Occurs.

The sub-scanning counter 142 controls the number of forced reset lines in the sub-scanning direction in order to forcibly skip the start position detection when there is a shadow or dirt at the read start position of the gradation pattern. If the line number counter is within the threshold value using the threshold parameter 145 of
Control is performed so that the sub-scanning counter value 142a does not count up. In combination with the control, the horizontal synchronization signal HDEN
Based on −0 and the vertical synchronization signal VDEN−0, counting in the sub-scanning direction is performed, and a sub-scanning counter value 142a is output.

The main scanning counter 143 outputs the horizontal synchronizing signal H
The master clock MCLK-0 is counted in synchronization with DEN-0, and the main scanning counter value 143a is output. The selector 146 outputs the generated sampling section valid signal 1
Using 41a, if the effective range, integrated data 148a
If the value is not within the valid range, the set numerical value 0 (hex) is selected and output. The value selected by the selector 146 is
The adder 147 adds the input image information to the input image information, and the result of the addition is stored in the flip-flop circuit 148. While the sampling section valid signal 141a is valid, the adder 14
At 7, the addition with the input image information is performed.

The added image information is divided by a divider 149 by a parameter 144a indicating the number of added pixels, thereby obtaining an average value 149a of each line. The average value 149a of each line is equal to the horizontal synchronization signal HDEN-0.
, Ie, at the end of one line, is latched by the flip-flop circuit 150. The value latched by the flip-flop circuit 150 is compared with a gradation pattern start position detection threshold parameter 152 by a comparator 151,
The comparison result 151a is output.

The selector 153 selects and outputs one of the output of the adder 154 and the counter initial value 0 (hex) according to the comparison result 151a of the comparator 151. In this case, when the comparison result 151a of the comparator 151 indicates that the value of the flip-flop circuit 150 is equal to or smaller than the threshold value, the selector 153 selects the initial value 0 (hex),
If it is larger than the threshold value, the selector 153 selects the output of the adder 154.

The value selected by the selector 153 is stored in the flip-flop circuit 155 at the rise of the horizontal synchronization signal HDEN-0. The adder 154 adds the output 155a of the flip-flop circuit 155 and a preset value 1 (hex).

When the average value of one line is larger than the threshold parameter 152 for detecting the start position of the gradation pattern, if a line that satisfies the condition is continuously input, the gradation start line counter value 155a (the flip-flop circuit 155)
Output) is counted up. The comparator 157 compares the gradation start line counter value 155a with the gradation pattern start determination line number threshold parameter 156, and outputs the comparison result as an operation start signal AVEST.

The operation start signal AVEST continues until the gradation start line counter value 155a exceeds this threshold value.
A signal for starting the operation is not sent to the average value calculating circuit 134 shown in FIG.
If 5a exceeds this threshold, an operation start signal AVEST is sent to the circuit shown in FIG. As a result, the average value calculation circuit 134 starts operating.

FIG. 5 shows a specific circuit configuration example of the average value calculation circuit 134. In FIG. 5, the sampling range control signal generator 161 includes a sub-scanning counter 16
2 and a counter value 163a output from the main scanning counter 163,
Based on the sub-scanning sampling parameter 164 and the main scanning start / end parameter 165 stored in the register, a signal indicating whether or not the area is a sampling area as shown in FIG.
61a is generated.

The sub-scanning counter 162 outputs a gradation pattern start signal AVEST output from the start position detection circuit 133.
Is used as a trigger for starting a sub-scanning count, the sub-scanning direction is counted by the horizontal synchronizing signal HDEN-0 and the vertical synchronizing signal VDEN-0, and the sub-scanning counter value 162a is output.

The main scanning counter 163 outputs the horizontal synchronizing signal H
The master clock MCLK-0 is counted in synchronization with DEN-0, and the main scanning counter value 163a is output. The selector 166 outputs the generated sampling section valid signal 1
61a, the integrated data 168a if it is in the effective range.
If the value is not within the valid range, the set numerical value 0 (hex) is selected and output. The value selected by the selector 166 is
The adder 167 adds the input image information to the input image information, and the addition result is stored in the flip-flop circuit 168. While the sampling section valid signal 161a is valid, the adder 16
At 7, the addition with the input image information is performed.

The added image information is divided by a divider 169 by a parameter 165a indicating the number of added pixels, thereby obtaining an average value 169a of each sampling range (sampling region of mode C in FIG. 9). The register setting timing generator 170 outputs the vertical synchronization signal VDE
By counting the master clock MCLK-0 in synchronization with N-0 and the horizontal synchronizing signal HDEN-0, a signal 170a indicating the address and timing for storing the average value 169a of each gradation and integrated data are stored. A signal 170b notifying the timing of clearing the flip-flop circuit 168 is generated.

The address at which the average value 169a of each gradation is stored indicates the address to be stored when one sampling area has been sampled.
The address is shifted each time one is completed. When the gradation pattern has been scanned, the register setting circuit / storage register 1
The data of each gradation is stored in 71. The value stored in the register setting circuit / storage register 171 is read by the main CPU 91, for example.

Next, a description will be given, with reference to the flowchart shown in FIG. 6, of a method of correcting characteristics in the image processing section 96 in the above-described configuration. The description will be made assuming that the multilevel halftoning level at the time of image information input is 8 bits. Also,
It is assumed that the switch 138 for turning on and off the operation of the start position detection circuit 133 is on.

First, on the operation panel 80, for example, a specific key operation is performed to set a characteristic correction data creation mode, and when an operation start command is input, the gradation gradually changes from the internal pattern generation unit 131. A pattern is generated. At this time, the generated gradation pattern is sent to the characteristic correction unit 137 via the data selection unit 132 which has selected the output of the internal pattern generation unit 131 by the data selection signal from the main CPU 91.

The characteristic correction section 137 corrects the gradation pattern from the internal pattern generation section 131 using preset characteristic correction data (this is referred to as first characteristic correction data). The gradation pattern is sent to the printer unit 6. The printer unit 6 outputs the corrected gradation pattern from the characteristic correction unit 137 as a hard copy on the paper P.

FIG. 7 shows an example of the output hard copy gradation pattern. Note that the numerical values (0,
, 170, 255) indicate the density value of each pattern.

The first set in the characteristic correction section 137
The characteristic correction data is, for example, data having a correction curve as shown in FIG. That is, the printer unit 6
The gradation characteristics of the hard copy output by the scanner unit 4
, The characteristic correction data having a correction curve such that the signal before correction and the signal corresponding to each output signal after input have a nearly linear relationship.

As described above, by correcting a part of the characteristics before outputting the gradation pattern from the internal pattern generation unit 131 as a hard copy and outputting the same, the system characteristics are not all, but are corrected to some extent. Then, the characteristics of the output hard copy become closer to linear.

The hard copy output by the printer unit 6 is set in the scanner unit 4, and
Read and input a hard copy gradation pattern. The input gradation pattern is sent to the start position detection circuit 133. The start position detection circuit 133 detects a read start position of the inputted gradation pattern from the inputted gradation pattern, and outputs a read start position signal.

The average value calculation circuit 134 receives the reading start position signal from the start position detection circuit 133 and calculates the average value of each gradation from the inputted gradation pattern for each gradation. The calculated average value of each gradation is sent to the characteristic correction data creation unit 135.

The characteristic correction data creating section 135 increases the calculated average value of each gradation by interpolation to a desired number of data, and, based on the gradation characteristics indicated by the calculated characteristic correction data, corrects the characteristic characteristics data (for this). Is referred to as second characteristic correction data).

The obtained characteristic correction data is stored in a characteristic correction data holding unit 13 capable of storing a plurality of characteristic correction data.
6. The characteristic correction data holding unit 136 includes:
According to various conditions, one of the held characteristic correction data is selected, and the selected characteristic correction data is sent to the characteristic correction unit 137.

With the above, the process of creating the characteristic correction data is completed, and the created characteristic correction data (second characteristic correction data) is used at the time of actual image processing. That is, at the time of actual image processing, the image information read from the original D by the scanner unit 4 is transmitted to the data selection unit 132 which has selected the input image information from the scanner unit 4 by the data selection signal from the main CPU 91 at this time. The signal is sent to the characteristic correction unit 137 via the FB. The characteristic correction unit 137 includes the characteristic correction data holding unit 1
Using the characteristic correction data (second characteristic correction data) from the printer 36, the gradation characteristic of the input image information is corrected, and the printer unit 6 or the page memory 98 is output as the output image information.
Send to

Next, in the processing described above, the processing of reading the gradation pattern input from the input system and calculating the average value of each gradation will be described in further detail. Conventionally, the reading of the input gradation pattern is performed by using the CP as described above.
In the present embodiment, the interrupt processing is performed by an interrupt process from U.
The reading speed is increased by using a hardware circuit to detect the start position of the gradation pattern and obtain the average value of multiple gradations, and the average value is calculated using more input image signals than before. By calculating, the data accuracy of the calculated average value is improved.

The gradation pattern to be generated will be described below by taking as an example a pattern in which the image signal changes in 17 steps in the sub-scanning direction as shown in FIG. The gradation pattern is
It is generated by the internal pattern generation unit 131, corrected by the characteristic correction unit 137, and output by the printer unit 6. At this time, the generated gradation pattern is sequentially output from an image signal having a small value to an image signal having a large value, and the width of each gradation is controlled to be equal. Still remain.

Then, using the remaining portion, the image is input from the scanner section 4 in the direction opposite to the output direction as shown in FIG. As shown in FIG. 9, the procedure for obtaining the average value of each gradation is performed by repeatedly operating the four modes A to D sequentially and partially according to conditions. The operation of each mode will be described below.

First, the A mode is a mode for detecting a reading start position of a gradation pattern, and the operation flow is shown in FIG. In addition, the respective symbols in FIG. 10 are listed below, and the processing operation will be described.

GAM [1] (1 bit): On / off switching of gradation pattern search operation FLDT (8 bits): Input image information SMPST (13 bits): Sampling start position SMPED (13 bits): Sampling end position THR1 (8 bits): Tone pattern cueing data threshold THR2 (8 bits): Tone pattern cueing line threshold YLIN (14 bits): Sub-scanning direction line counter HLIN (10 bits): Actual line counter number HISRST ( 9-bit): Number of sub-scanning histogram forced reset lines When GAM [1] = 0, detection of the read start position of the gradation pattern is performed. The input image signal is skipped until the actual line counter number HLIN in the sub-scanning direction exceeds a preset threshold value HISRST. This is at the beginning of the input image signal
Unnecessary data such as the shadow of the platen may enter due to a shift in the reading start position. In this case, the unnecessary data is used to prevent the reading start position detection process from starting from an unexpected place. This is the process.

Next, the average value of the data in the sampling area in the main scanning direction specified in units of one line is obtained. Since the start position detection circuit 133 has a hardware circuit configuration, it can be added at the same speed as the input speed of the input image signal to obtain an average value. The average value obtained for each line is compared with a preset threshold value THR1, and if the average value is larger than the threshold value THR1, it is determined that the read position has been applied to the gradation pattern portion, and the read start position is determined. Decide temporarily. Assuming a case where the gradation pattern is partially contaminated and, for example, the threshold exceeds only one line and the relationship between the average value and the threshold is maintained for the number of lines determined by another threshold THR2, For the first time, it is determined that the gradation pattern has really started, and the process proceeds to the next B mode.

Next, the B mode is a mode in which the gradation data portion where the gradation pattern is not sampled is skipped, and the flow of the operation is shown in FIG. Note that FIG.
Are listed below, and the processing operation will be described.

THR3 (10 bits): gradation pattern skip line threshold 1 YLIN (14 bits): sub-scanning line counter The sub-scanning line counter YLIN counts up by one for each line. Until this counter value exceeds the threshold value THR3, the input image signal is skipped without doing anything. When the value of the sub-scanning direction line counter YLIN becomes equal to or more than the threshold value THR3, the process proceeds to the next C mode.

Next, the C mode is a mode for calculating the average value of each gradation data, and the operation flow is shown in FIG. In addition, the respective symbols in FIG. 12 are listed below, and the processing operation will be described.

FLDT (8 bits): input image information SMPST (13 bits): histogram sampling start position SMPED (13 bits): histogram sampling end position THR4 (13 bits): gradation pattern calculation line threshold THR5 (6 bits) : Tone pattern number counter threshold value KCON (6 bits): Tone pattern number counter YLIN (14 bits): Sub-scanning direction line counter As shown in FIG. 13, reading for obtaining an average value of one gradation in the sub-scanning direction The width is given by a threshold value THR4. When the sub-scanning direction line counter YLIN is smaller than the threshold value THR4, the value of the input image signal of the sampling area specified by SMPST and SMPED is continuously added in the main scanning direction.

At this time, although not particularly mentioned in FIG. 12, it is also possible to perform sampling and addition while thinning out data for only one pixel out of N pixels in the sampling area.
Since the number of data to be added directly leads to an increase in the circuit scale, in order to prevent this, the sampling operation must be performed in accordance with the characteristics of the machine, such as by reducing the sampling width and not thinning out, or by expanding the sampling area and thinning out. It is also possible to select.

When the addition by the threshold value THR4 in the sub-scanning direction is completed, the average value is obtained by dividing the addition value by the number of pixels added. The obtained average value is used as the gradation pattern number counter KCON
And store it in the register address controlled by.
The value of the gradation pattern number counter KCON is a counter value of the gradation number. When the value of the gradation pattern number counter KCON is smaller than the gradation number printed on the gradation pattern set to the threshold value THR5, the D mode Move on to

When the value of the gradation pattern number counter KCON becomes equal to or larger than the threshold value THR5, the mode is not shifted to the next mode, and an end flag GAM [2] = 1 is set to set a flag indicating the end. After the reading of the gradation pattern output from the printer unit 6 is completed, it is possible to confirm from this flag whether the average value has been calculated for the number of gradations determined by the threshold value THR5.

Next, the D mode is a mode in which the grayscale data portion not sampled is skipped, and the flow of the operation is shown in FIG. 14 are listed below, and the processing operation will be described.

THR6 (10 bits): Line threshold 2 for gradation pattern skipping YLIN (14 bits): Sub-scanning direction line counter In order to skip portions unnecessary for gradation pattern sampling, a sub-scanning direction line counter YLIN is used. It counts up for each line and compares it with the threshold value THR6. When the value of the sub-scanning direction line counter YLIN becomes equal to or greater than the threshold value THR6, C
Return to mode.

As described above, the A to D modes are sequentially operated while being partially looped, and the average value of each gradation is obtained. This process is performed in real time, and the calculation of the average value is completed when the reading of the gradation pattern is completed. Therefore, the average value held in the register of each gradation is immediately read from the main CPU 91 after the reading is completed. Can be read from.

The subsequent processing is performed by the main CPU 91. Here, switching the place where processing is performed from hardware to software is called an average value.
The calculation is simple, but where speed is required, the calculation is performed using a hardware circuit, and the part for obtaining the characteristic correction data using the average value calculated using the hardware circuit is a variation in the calculation method. There is
This is because it is appropriate to use a CPU that can be changed if necessary.

Based on the plurality of average values read from the register, the main CPU 91 calculates according to the following procedure, and obtains gradation characteristic correction data (second characteristic correction data).
Ask for.

First, the multi-valued number of normally used image information is generally 8 bits = 256 gradations, but the number of data of the average value obtained as described above is smaller than this number of gradations. Few. Therefore, in order to obtain correction data for each gradation, the number of data of the average value is increased in advance by interpolation to the number of multivalued image information. As the interpolation method, for example, 1. Linear interpolation 2. Least squares method Although an interpolation method such as spline interpolation is generally used, interpolation may be performed by another method according to the purpose. If the average number of data is "1
FIG. 8 shows a case where interpolation is performed up to 256 at "7". This is an example of the result of performing interpolation by spline interpolation.

The data obtained by performing interpolation and increasing the number of data in this manner shows the gradation characteristics of the system. To correct this so that the data before output becomes the same as the data after output, the inverse characteristic of the characteristic of this system may be obtained. This inverse characteristic may be obtained by obtaining a straight line, a curve contrasting with y = x, with respect to a curve indicating the relationship between input and output created from data. Assuming that a curve indicating the input / output relationship obtained by the interpolation is c, the temporary characteristic correction data f 'indicating the inverse characteristic can be obtained as follows.

F ′ [n] = i (n = 0, 1, 2,..., 255) where i is i satisfying the following expression. i ≦ c [i] <i + 1 (i = 0, 1, 2,..., 25
5) f ': provisional characteristic correction data c: gradation characteristic curve of the system Once the provisional characteristic correction data f' is obtained, the pattern generated by the internal pattern generation unit 131 is corrected by the characteristic correction unit 137. In combination with the first characteristic correction data used at the time of performing, the second characteristic correction data f is obtained as follows.

F [n] = f '[fo [n]] (n =
0, 1, 2,..., 255) f ': provisional characteristic correction data fo: first characteristic correction data f: second characteristic correction data The second characteristic correction data thus obtained is subjected to characteristic correction. The data is held in the data holding unit 136.

As described above, although the processing takes time, the operation itself is a part having simple contents (start position detecting circuit 1).
33, by using a hardware circuit for the average value calculation circuit 134), the read time of the gradation pattern, which conventionally required about 30 seconds, can be reduced to about 1.5 to 3 seconds, and the number of sampling data is also reduced. Since it can be increased 30 times or more, the reliability of the data accuracy of the average value is also increased.

In the subsequent calculation processing, since the calculation method can be easily rewritten by using the CPU as in the conventional case, the interpolation processing and the calculation for obtaining the characteristic correction data are always the most efficient. A good calculation method can be used, and there is an advantage that even if a problem occurs with the processing method once determined, it is easy to cope with the problem.

Therefore, when preparing characteristic correction data for correcting the input and output characteristics of each aircraft throughout the entire system, it is possible to obtain the characteristic correction data as expected with high data accuracy and reliability in a short time. And the effect that the calculation method can be easily changed is obtained.

Therefore, by correcting the gradation characteristics of the input image information from the scanner unit 4 by using the characteristic correction data obtained in this way, the delicate halftone part is also optimized, and the stable image quality is always maintained. A copy image is obtained.

In the above embodiment, the characteristic correction unit 1
It has been described that only one first characteristic correction data set at 37 is provided for the sake of simplicity. However, in practice, a plurality of first characteristic correction data are set in advance. For example, by performing a selection operation on operation panel 80, a desired first
Is selected, and the selected first characteristic correction data is used.

[0105]

As described above in detail, according to the present invention, when the characteristic correction data for correcting the input and output characteristics of each aircraft through the entire system is created, the reliability of the data accuracy can be reduced in a short time. And an image processing apparatus capable of creating expected characteristic correction data.

[Brief description of the drawings]

FIG. 1 is a side view schematically showing an internal configuration of a digital copying machine according to an embodiment of the present invention.

FIG. 2 is a block diagram schematically showing a flow of signals for electrical connection and control of the digital copying machine shown in FIG. 1;

FIG. 3 is a block diagram illustrating a configuration of an image processing unit.

FIG. 4 is a block diagram showing a specific configuration example of a start position detection circuit.

FIG. 5 is a block diagram showing a specific configuration example of an average value calculation circuit.

FIG. 6 is a flowchart illustrating a characteristic correction method in the image processing unit.

FIG. 7 is a view showing an example of a gradation pattern output on paper as a hard copy.

FIG. 8 is a diagram showing first characteristic correction data used when performing gradation characteristic correction on a gradation pattern.

FIG. 9 is an image diagram illustrating a creation method performed by a characteristic correction data creation unit.

FIG. 10 is a view for explaining the flow of operation in the A mode in the image diagram of FIG. 9;

FIG. 11 is a view for explaining the flow of operation in a B mode in the image diagram of FIG. 9;

FIG. 12 is a view for explaining the flow of operation in C mode in the image diagram of FIG. 9;

FIG. 13 is a view for explaining an area in which values of each gradation of an inputted gradation pattern are sampled;

FIG. 14 is a view for explaining the flow of operation in the D mode in the image diagram of FIG. 9;

[Explanation of symbols]

4 scanner unit (input unit, reading unit), 6 printer unit (output unit, image forming unit), 80 operation panel, 90 main control unit, 91 main CPU, 96
... image processing unit, 131 ... internal pattern generation unit (gradation pattern generation means), 132 ... data selection unit, 133 ...
... Start position detection circuit, 134 ... Average value calculation circuit, 13
5 ... Characteristic correction data creation unit (characteristic correction data creation unit), 136 ... Characteristic correction data holding unit (storage unit),
137 ... Characteristic correction unit (characteristic correction means) 138 ... Switch

Claims (16)

[Claims] 1. An image processing method comprising: performing predetermined processing on image information input from an input means; and outputting the image information by an output means; a gradation pattern generating means for generating a gradation pattern; A first characteristic correction unit that corrects a gradation characteristic of the gradation pattern generated by the tone pattern generation unit using first characteristic correction data stored in advance; Tone pattern output means for outputting the corrected tone pattern using the output means, tone pattern input means for inputting the tone pattern output from the tone pattern output means using the input means, An average value calculating circuit for calculating an average value of each tone based on the tone pattern input by the tone pattern input means; and an average value of each tone determined by the average value calculating circuit. A characteristic correction data generating means for generating second characteristic correction data for correcting the gradation characteristic based on the second characteristic correction data generated by the characteristic correction data generating means; An image processing apparatus comprising: a second characteristic correction unit configured to correct gradation characteristics of input image information. 2. A gradation pattern generating means for performing a predetermined process on image information input from an input means and outputting the image information by an output means, comprising: a gradation pattern generating means for generating a gradation pattern; A first characteristic correction unit that corrects a gradation characteristic of the gradation pattern generated by the tone pattern generation unit using first characteristic correction data stored in advance; Tone pattern output means for outputting the corrected tone pattern using the output means, tone pattern input means for inputting the tone pattern output from the tone pattern output means using the input means, A start position detection circuit for detecting a start position of a gradation pattern from an image signal of the gradation pattern input by the gradation pattern input means; An average value calculating circuit for obtaining an average value of each tone from the start position of the tone pattern; and a second characteristic for correcting the tone characteristics based on the average value of each tone obtained by the average value calculating circuit. A characteristic correction data generating unit for generating correction data; and a second characteristic correcting unit for correcting a gradation characteristic of the image information input by the input unit using the second characteristic correction data generated by the characteristic correction data generating unit. An image processing apparatus, comprising: a characteristic correcting unit. 3. The image processing apparatus further comprises a holding circuit for holding an average value of each gradation obtained by the average value calculation circuit.
The characteristic correction data generating means reads out the average value of each gradation stored in the holding circuit and generates second characteristic correction data for correcting the gradation characteristic based on the read average value of each gradation. 3. The method according to claim 1, wherein
The image processing apparatus according to any one of the preceding claims. 4. When the second characteristic correction data is generated based on the average value of each gradation, the missing data between the gradations is directly interpolated, spline interpolation, or interpolation using the least squares method. The image processing apparatus according to claim 1, wherein interpolation is performed using any one of the methods. 5. The start position detection circuit calculates an average value within a predetermined range from an image signal of a gradation pattern input by the gradation pattern input means, and calculates the average value in advance. 3. The image processing apparatus according to claim 2, wherein a start position of the gradation pattern is detected by comparing the set position with a set threshold value. 6. The apparatus further comprises means for turning on and off the operation of the start position detection circuit, and when the operation of the start position detection circuit is turned off, the start position of the gradation pattern by the start position detection circuit. 3. The image processing apparatus according to claim 2, wherein a process of calculating an average value of each gradation by the average value calculation circuit is performed without performing the detection process. 7. A method of digitizing image information input from an input means, subjecting the digitized image information to processing according to the purpose, and outputting the image information by an output means. A gradation pattern generating means for generating a changing gradation pattern; and a gradation characteristic corrected for the gradation pattern generated by the gradation pattern generating means using first characteristic correction data stored in advance. A first characteristic correction unit for performing the operation, a gradation pattern output unit for outputting the gradation pattern corrected by the first characteristic correction unit by using the output unit, and a gradation output by the gradation pattern output unit. A tone pattern input means for inputting a tone pattern using the input means; and an image signal of the tone pattern input by the tone pattern input means to determine a start position of the tone pattern. A starting position detection circuit for outputting the gradation pattern; an average value calculation circuit for obtaining an average value of each gradation by sampling each gradation from a start position of the gradation pattern detected by the start position detection circuit; A characteristic correction data creating means for creating, for each tone, second characteristic correction data for correcting the tone characteristics based on the average value of each tone obtained by the calculation circuit; An image processing apparatus comprising: a second characteristic correction unit configured to correct gradation characteristics of image information input by the input unit using the second characteristic correction data obtained. 8. A holding circuit for holding an average value of each gradation obtained by the average value calculation circuit,
The characteristic correction data generating means reads out the average value of each gradation stored in the holding circuit and generates second characteristic correction data for correcting the gradation characteristic based on the read average value of each gradation. The image processing apparatus according to claim 7, wherein: 9. The image processing apparatus according to claim 7, wherein a portion to be sampled for each gradation in said average value calculation circuit can be changed. 10. An image processing method comprising the steps of: digitizing image information input from an input means, subjecting the digitized image information to processing according to a purpose, and outputting the image information by an output means; A gradation pattern generating means for generating a changing gradation pattern; and a gradation characteristic corrected for the gradation pattern generated by the gradation pattern generating means using first characteristic correction data stored in advance. A first characteristic correction unit for performing the operation, a gradation pattern output unit for outputting the gradation pattern corrected by the first characteristic correction unit by using the output unit, and a gradation output by the gradation pattern output unit. A tone pattern input means for inputting a tone pattern using the input means, and a tone pattern input in real time from an image signal of the tone pattern input by the tone pattern input means. Start position detection circuit for detecting a start position of the tone pattern, and an average value calculation circuit for calculating an average value of each gradation within a preset range from the start position of the gradation pattern detected by the start position detection circuit. A register for holding the average value of each gradation obtained by the average value calculation circuit; and a reading means for reading the average value of each gradation stored in the register using a CPU (Central Processing Unit). From the average value of each gradation read by the reading means,
And an interpolation means for increasing the number of data by interpolation so that the number of data of the average value becomes a preset number of data, and a gradation characteristic indicated by the data increased by the interpolation means. A characteristic correction data generating means for generating second characteristic correction data for correcting the gradation characteristic for each gradation; and a storage for storing the second characteristic correction data generated by the characteristic correction data generating means. Means, and second characteristic correction means for correcting, based on the second characteristic correction data stored in the storage means, the gradation characteristic of the image information input by the input means by setting of the CPU. An image processing apparatus characterized in that: 11. An image of a document is read by a reading unit, image information is input, a predetermined process is performed on the input image information, and the image information is stored on an image forming medium by an image forming unit. In an image processing apparatus for forming and outputting, a gradation pattern generating means for generating a gradation pattern that changes stepwise, and a first pre-stored gradation pattern generated by the gradation pattern generating means. First characteristic correction means for correcting gradation characteristics using characteristic correction data, and forming and outputting a gradation pattern corrected by the first characteristic correction means on an image forming medium using the image forming means Gradation pattern output means for inputting the gradation pattern on the image forming medium output by the gradation pattern output means by using the reading means; A start position detection circuit for detecting a start position of the gradation pattern from an image signal of the gradation pattern input by the pattern input means; and a start position of the gradation pattern detected by the start position detection circuit. An average value calculating circuit for obtaining an average value; and characteristic correction data generating means for generating second characteristic correction data for correcting a grayscale characteristic based on the average value of each gradation obtained by the average value calculating circuit. And second characteristic correction means for correcting the gradation characteristic of the image information input by the reading means using the second characteristic correction data created by the characteristic correction data creation means. An image processing apparatus characterized by the above-mentioned. 12. The image processing apparatus according to claim 1, further comprising: a holding circuit for holding an average value of each tone obtained by said average value calculation circuit, wherein said characteristic correction data creating means includes an average value of each tone held by said holding circuit. 12. The image processing apparatus according to claim 11, wherein the second characteristic correction data for correcting the gradation characteristic is created based on the read average value of each gradation. 13. A latent image forming means for forming a latent image based on image information on an image carrier, and a developing means for developing the latent image on the image carrier formed by the latent image forming means with a developer. Transfer means for transferring the developer image on the image carrier, which has been developed by the developing means, onto an image forming medium; gradation pattern generation means for generating a gradation pattern that changes stepwise; A first characteristic correction unit for correcting a gradation characteristic of the gradation pattern generated by the gradation pattern generation unit by using first characteristic correction data stored in advance; and a first characteristic correction unit. A gradation pattern output means for forming and outputting the gradation pattern corrected by the above on the image forming medium using the latent image forming means, the developing means, and the transfer means; Tone pattern on image forming medium Reading means for reading and inputting a pattern, a starting position detecting circuit for detecting a starting position of the gradation pattern from the image signal of the gradation pattern inputted by the reading means, and a reading means for detecting the starting position of the gradation pattern. An average value calculating circuit for obtaining an average value of each tone from the start position of the tone pattern; and a second characteristic for correcting the tone characteristics based on the average value of each tone obtained by the average value calculating circuit. A characteristic correction data generating means for generating correction data; and a second characteristic correcting means for correcting the gradation characteristic of the image information using the second characteristic correction data generated by the characteristic correction data generating means. An image processing apparatus comprising: 14. The image processing apparatus according to claim 1, further comprising: a holding circuit for holding an average value of each tone obtained by said average value calculating circuit, wherein said characteristic correction data creating means includes an average value of each tone held by said holding circuit. 14. The image processing apparatus according to claim 13, wherein the second characteristic correction data for correcting the gradation characteristic is created based on the read average value of each gradation. 15. A method for performing predetermined processing on image information input from an input means and outputting the image information by an output means, comprising: a gradation pattern generating means for generating a gradation pattern; Tone pattern output means for outputting the tone pattern generated by the tone pattern generation means using the output means; and a floor for inputting the tone pattern output from the tone pattern output means using the input means. Tone pattern input means, an average value calculation circuit for calculating an average value of each tone based on the tone pattern input by the tone pattern input means, and an average value of each tone determined by the average value calculation circuit. A characteristic correction data generating means for generating characteristic correction data for correcting the gradation characteristic based on the characteristic correction data generated by the characteristic correction data generating means; And a characteristic correcting unit for correcting a gradation characteristic of the image information input by the input unit. 16. A gradation pattern generating means for performing a predetermined process on image information inputted from an input means and outputting the image information by an output means, comprising: a gradation pattern generating means for producing a gradation pattern; Tone pattern output means for outputting the tone pattern generated by the tone pattern generation means using the output means; and a floor for inputting the tone pattern output from the tone pattern output means using the input means. Tone pattern input means, a start position detection circuit for detecting a start position of the tone pattern from an image signal of the tone pattern input by the tone pattern input means, and a tone detected by the start position detection circuit An average value calculation circuit for calculating an average value of each gradation from the start position of the pattern; and a gradation characteristic is corrected based on the average value of each gradation calculated by the average value calculation circuit. Characteristic correction data generating means for generating characteristic correction data for performing the correction, and using the characteristic correction data generated by the characteristic correction data generating means to correct the gradation characteristic of the image information input by the input means. An image processing apparatus comprising: a correction unit.