JP2010114648A - Image processor, image processing method, and program executable by computer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image processor for simply reducing difference in image density of data read out from the surface and the rear surface with high accuracy when images formed on the surface and the rear surface of a document are read out by conveying a document only once, an image processing method, and a program executable by a computer. <P>SOLUTION: In outputting a test chart for a first face and a test chart for a second face of one and the same printing medium, respectively, configuration patterns different between the first face and the second face are output to perform calibration. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image processing device, an image processing method, and a computer-executable program, and more specifically, an image processing device, an image processing method, and a computer that execute calibration by reading a test chart pattern. Regarding the program.

  It is known that the gradation characteristics change with time in electrophotographic and ink jet copying machines. Calibration is performed to calibrate this change. Here, calibration refers to printing a test chart composed of a plurality of patches having different densities on a sheet, reading the printed test chart with a scanner, and performing gradation correction based on the read density information. By performing such calibration, it is possible to obtain gradation characteristics close to the target value while suppressing changes in gradation characteristics due to changes with time.

  2. Description of the Related Art A copying machine has been proposed in which two image reading units are provided on both front and back sides of a document path for transporting a document, and both sides of the document can be simultaneously read and printed on both sides by a single document transport. When reading a document, for example, a method of irradiating light with a fluorescent lamp as a light source and reading reflected light from the document with an optical sensor via a reduction optical system is adopted. As an optical sensor in this system, for example, a one-dimensional CCD (Charge Coupled Device) sensor is used, and one line is processed simultaneously. In this method, when reading of one line in the line direction (scanning main scanning direction) is completed, the original is moved by a small distance in a direction (sub-scanning direction) perpendicular to the main scanning direction, and the next line is read. This is repeated over the entire document size to complete one page of document reading. Further, as a method of sequentially reading in the sub-scanning direction without moving the document, there is a method of sequentially reading in the sub-scanning direction by moving a plurality of mirrors by a moving body such as a full-rate carriage or a half-rate carriage. .

  In this reading method, as described above, since the light source is applied to the original and the reflected light needs to be read by the CCD sensor via several mirrors, the entire unit tends to be large. In particular, when it is necessary to provide a plurality of image sensors in order to read both sides without inverting the document, it is difficult to provide a plurality of such CCD sensors due to space constraints. Therefore, in order to solve the problem of such a space, a CIS (Contact Image Sensor) that uses an LED (Light Emitting Diode) having a small shape as a light source and directly reads an image with a linear sensor via a Selfoc lens, for example. There is a method using an image sensor called.

  For copiers capable of simultaneous duplex scanning and duplex printing, density characteristics may differ between printing on the front side and printing on the back side, so calibration must be performed to reduce the density difference between the front and back sides. . For example, in Patent Document 1, an image reading apparatus including a CCD image sensor that reads a first surface of a conveyed document as a color image or a black and white image and a CIS that reads a second surface of the conveyed document as a black and white image. In the one-sided duplex simultaneous reading mode in which both sides of the document are read as a black and white image by transporting the document once, the color image data on the first surface read by the CCD image sensor is used to read the first image. A technique is disclosed in which monochrome image data on one side is corrected and the image density is made close to the monochrome image data on the second side read by the CIS.

  In such a situation, when it is considered to perform calibration, it takes time and effort to perform calibration on the scanner side and calibration on the plotter side twice. Further, when performing calibration, conventionally, a calibration pattern for each sheet is output and read by each reading device. Even when the same pattern is read, the calibration result varies depending on the reading position of the reading device. Therefore, the density characteristic may change. For this reason, it is desirable to reduce the number of calibrations and save the user time, and to efficiently perform calibration for reducing the density difference caused by simultaneous reading on both sides.

Japanese Patent Laying-Open No. 2005-210268

  The present invention has been made in view of the above, and when reading an image formed on both the front and back sides of a document with a single conveyance of the document, the difference in image density between the read data on the front and back surfaces can be easily increased. An object is to provide an image processing apparatus, an image processing method, and a computer-executable program capable of reducing the accuracy.

  In order to solve the above-described problems and achieve the object, the present invention provides an image processing apparatus that performs calibration by reading a test chart pattern, a paper feeding unit that feeds a document, and a paper feeding unit that feeds the original. A transport path through which the paper document is transported, a first reading unit that reads an image on the first surface of the document from one side of the transport path, and the one side through the transport path A second reading unit that reads an image on the second side of the document from the opposite side, an image output unit configured to print on both sides of the print medium, and an image output unit configured to print the image on the print medium; Test chart output means for causing the image output means to print out a test chart composed of a plurality of patch patterns on the print medium, the test chart having a pattern on the first surface and the second surface; Characterized in that it comprises.

  Further, in order to solve the above-described problems and achieve the object, the present invention relates to an image processing method for performing calibration by reading a test chart pattern, and conveying a document fed by a sheet feeding unit. A step of reading an image of the first surface of the document from one side of the path by a first reading unit; and the second side of the document from the other side facing the one side through the conveyance path. A step of reading an image by a second reading unit, and a step of printing out a test chart composed of a plurality of patches on a printing medium, wherein the test chart has a pattern on the first surface and the second surface. It is characterized by being different.

  Further, in order to solve the above-described problems and achieve the object, the present invention provides a program mounted on an image processing apparatus that performs calibration by reading a test chart pattern, and feeds paper to a computer by a paper feeding unit. A step of reading an image on the first surface of the original from one side of a conveyance path through which the prepared original is conveyed, and the other side facing the one side via the conveyance path Reading the image on the second surface of the original by a second reading unit and printing a test chart composed of a plurality of patch patterns on the print medium and outputting the test chart. The chart is characterized in that the pattern differs between the first surface and the second surface.

  According to the present invention, in an image processing apparatus that performs calibration by reading a pattern of a test chart, a paper feeding unit that feeds a document, and a conveyance path through which the document fed by the paper feeding unit is conveyed A first reading unit that reads an image on the first surface of the document from one side of the transport path, and the second side of the document from the other side that faces the one side through the transport path. A second reading unit for reading an image, double-sided printing of a printing medium is possible, an image output unit for printing out an image on the printing medium, and a plurality of patch patterns on the image output unit And a test chart output means for printing out the test chart to be printed on the printing medium. Since the test chart has different patterns on the first surface and the second surface, the document is conveyed once. It is possible to provide an image processing apparatus capable of reducing a difference in image density between read data on both front and back sides with a simple method and with high accuracy when reading images formed on both sides of a document. There is an effect.

  Hereinafter, preferred embodiments of an image processing apparatus, an image processing method, and a computer-executable program according to the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or that are substantially the same.

(Embodiment 1)
FIG. 1 is an overall configuration diagram of a digital image processing apparatus (MFP: Multifunction Peripheral) according to Embodiment 1 of the present invention. As shown in FIG. 1, the digital image processing apparatus includes a reading device (double-sided simultaneous reading device) 1, an image data processing device 2, a bus control device 3, an HDD 4, a CPU 5, a memory 6, a plotter I / O. F device 7, plotter device 8, operation display device 9, line I / F device 10, external I / F device 11, and S.F. B. 12, a ROM 13, and an internal speaker device 17.

  The reading device 1 is configured to be capable of simultaneous reading on both sides, generates 8-bit RGB digital image data based on the density information of the document obtained by scanning the document, and outputs the digital image data to the image data processing device 2. To do. The image data processing device 2 performs image processing, which will be described later, on the digital image data input from the reading device 1 and outputs it to the bus control device 3.

  The bus control device 3 exchanges various data such as image data and control commands necessary in the digital image processing device. The HDD 4 is a storage device for accumulating digital image data and accompanying information of the digital image data. The CPU 5 is a microprocessor that controls the entire control of the digital image processing apparatus in accordance with a program stored in the ROM 13. The memory 6 is a volatile memory used for temporarily storing programs and intermediate processing data when the CPU 5 controls the digital image processing apparatus.

  The plotter I / F device 7 receives CMYK digital image data sent from the CPU 5 and outputs it to the plotter I / F device 7 which is a dedicated I / F of the plotter device 8. The plotter device 8 is configured to be able to perform double-sided printing. Upon receiving CMYK digital image data, the plotter device 8 prints out the transfer paper by an electrophotographic process using a laser beam.

  S. B. Reference numeral 12 denotes a general-purpose circuit that is a bridge function of a bus called South Bridge. The ROM 13 is a memory that stores a program when the CPU 5 controls the digital image processing apparatus. The operation display device 9 is a user interface of the digital image processing device, and includes an LCD (liquid crystal display device) and a key switch. The operation display device 9 displays various states and operation methods of the device on the LCD, and receives a key switch input from the user. Detect. The internal speaker device 17 generates a sound and a specific warning sound according to the action of the operation display device 9.

  The digital image processing apparatus exchanges image data via the FAX 14 outside the apparatus and the telephone line / line I / F device 10. Further, the digital image processing apparatus (MFP) performs various controls and input / output of image data via the PC 15 outside the apparatus, the network (Ethernet (registered trademark)), and the external I / F apparatus 11.

  FIG. 2 is a diagram illustrating a schematic mechanical configuration of the reading device 1. In FIG. 2, a reader 1 includes a first traveling body 112 including a light source 111 configured by a xenon lamp or a fluorescent lamp, a white plate 110 to be exposed, and a mirror 113, and mirrors 114 and 115. The second traveling body 116, the lens 117, the first reading unit 118 (one-dimensional CCD in the first embodiment), the sheet through document feeder (SDF) unit 104, and the upper part of the document pressing plate are provided. A document table 101 is provided.

  In the SDF unit 104, the stepping motor 106 is driven by the CPU 5, and the document 100 set on the document table 101 is transported via the separation roller 102 and the transport roller 105, and a predetermined traveling body 112 has a predetermined value. Transport to the reading position. At this time, the document 100 is conveyed at a constant speed, and the first traveling body 1112 stops the image data of the first surface (front surface) of the document surface with the first reading unit 118 (the embodiment). 1 is read by a one-dimensional CCD (Charge Coupled Device) sensor. At the time of double-sided reading, after the white reference plate 107 is read, the back side of the original 100 is irradiated with light from the back side reading lamp 108, and the reflected light is emitted from the second reading unit 109 (in the first embodiment, a plurality of readings). CIS (Contact Image Sensor)) to obtain digital image data of the second side (back side) of the document. Thereby, the image data of the front side and the back side of the document can be obtained simultaneously.

  FIG. 3A is a diagram illustrating a schematic arrangement example of the first reading unit 108. As shown in FIG. 3A, in the first reading unit 108, a one-dimensional CCD (Charge Coupled Device) sensor is arranged in a direction orthogonal to the main scanning direction. FIG. 3B is a diagram illustrating a schematic arrangement example of the second reading unit 109. As shown in FIG. 3B, the second reading unit 109 is arranged in a staggered manner in which the first to third CIS1, CIS2, and CIS3 are arranged in a direction orthogonal to the main scanning direction. The reading range of each CIS is overlapped.

  FIG. 4 is a diagram illustrating a configuration example of the image data processing device 2. The image data processing device 2 includes a scanner γ conversion unit 21, a filter processing unit 22, a color correction unit 23, a γ correction unit 24, a gradation processing unit 25, and a test chart output unit 26.

  The image data processing device 2 performs image processing on the input image data on the first side and the input image data on the second side read by the reading device 1.

  The scanner γ conversion unit 21 converts the device RGB into a specific color space. Filter processing unit Filter processing 22 smoothes the photographic part of the image and emphasizes the character part. The color correction unit 23 performs an ink process or the like on the RGB color space generated by the scanner γ conversion unit 21 and converts it into a CMYK color space. The γ correction unit 24 reads when a γ correction processing unit 31 that performs γ conversion using a γ correction table and a calibration execution command are input according to the image quality mode and the type of gradation processing to be used. A calibration processing unit 32 that corrects the γ correction table of the γ correction processing unit 31 and creates a γ correction table so that the density data of the test chart read by the apparatus 101 becomes a target value. . The gradation processing unit 25 performs gradation processing such as dither processing and error diffusion.

  The test chart output unit 26 stores test chart data, and causes the plotter device 8 to output a test chart composed of a plurality of patch patterns having different densities when calibration is executed.

  5A is an example of the first surface of the test chart, and FIG. 5B is an example of the second surface of the test chart. In FIGS. 5A and 5B, the wavy line is for explaining the position of the pattern and is not formed on the test chart. In the test chart, as shown in FIGS. 5A and 5B, patterns having different configurations are formed on the first surface and the second surface. On the second surface, a pattern is output at a position that is not a joint of CIS1 to CIS3 so as to avoid overlap between CIS1 to CIS3 or adjacent positions. On the first surface, a pattern is output at a position corresponding to the joint between CISs 1, 2, and 3, that is, a position that does not overlap with the pattern on the second surface. Since the patterns on the first surface and the second surface are displaced from each other, even if there is a show-through, the density of the patch on the pattern on the opposite side is not affected.

  Next, the calibration procedure of the digital image processing apparatus shown in FIG. 1 will be described. FIG. 5C is a flowchart for explaining the calibration procedure of the digital image processing apparatus.

  First, when an instruction to print a test chart for calibration is input from the operation display device 9 (step S1), the test chart output unit 26 of the image data processing device 2 displays the first surface (front surface) of the same printing paper. And a test chart for the first surface and a test chart for the second surface are respectively output to the second surface (back surface) (step S2).

  The user or service person sets the first side of the test chart on the document table 101 of the reading apparatus 1 with the first side of the test chart facing up (step S3). When a calibration execution instruction is input from the operation display device 9 (step S4), the reading device 1 simultaneously reads the patterns on the first surface and the second surface of the test chart, and reads the first surface and the first surface read. The pattern data of the two surfaces is output to the image data processing device 2 (step S5). In the image data processing device 2, the pattern data of the first surface and the second surface is subjected to scanner γ conversion by the scanner γ conversion unit 21, filter processing by the filter processing unit 22, and color conversion by the color correction processing unit 23. Is input to the γ correction unit 24.

  In the γ correction unit 24, the calibration processing unit 32 converts the pattern data read on the first surface and the second surface into values converted from density or values calculated from Lab, respectively, and is determined according to predetermined input characteristics. First and second surface γ tables are created to correct the difference from the target density or target distance value (correction data) (step S6). Note that a specific method of calibration based on the read pattern data can use the method described in Japanese Patent No. 3789662, and detailed description thereof will be omitted here. The γ table created by the calibration processing unit 32 is stored in the γ correction processing unit 31, and the read data of the first surface is subjected to γ conversion using the γ table for the first surface. Γ conversion is performed on the reading data of the second surface by using the γ table for the second surface. As a result, a printed image with a small difference in image density between the front and back sides of the document can be obtained by simple calibration.

  FIG. 6 is a diagram for explaining the γ table. In FIG. 6, the horizontal axis indicates the input (test chart density), the vertical axis indicates the distance value, the target is the target value (distance value), and the distance value is obtained from the values read by CIS1, CIS2, CIS3, and CCD. The case where is calculated is shown. A γ table is created from the difference between the target value and each of the CIS1, CIS2, CIS3, and distance values in the CCD.

  That is, a γ table for a CCD (single image sensor) is created for the first surface. On the other hand, for the second surface, there are two joints of CIS1, CIS2, and CIS3, and since there are three types of output CMYK patterns, three types of γ tables are created for each CIS. This makes it possible to create a γ table that can reduce the density difference at the time of output even when the change over time and the reading device are different, and it is possible to perform appropriate calibration according to the configuration of the reading device Become.

  Here, a γ table is created for each CIS, but one γ table may be created by weighted averaging the input / output relationship of each CIS.

  In the present embodiment, the CCD is used for the first surface and the plurality of CISs are used for the second surface. However, the present invention is not limited to this, and both the first surface and the second surface are used. May be CIS.

  According to the first embodiment, when outputting a test chart for the first surface and a test chart for the second surface to the first surface and the second surface of the same print medium, respectively, the first surface and the second surface Because it is decided to output and calibrate a pattern with a different configuration, the optimal calibration can be performed according to the configuration of the reading unit, and images formed on both the front and back sides of the document can be read with a single transport of the document. At this time, it is possible to reduce the image density difference between the read data on the front and back surfaces with a simple method and with high accuracy.

  Further, according to the first embodiment, a pattern is output at a position corresponding to the joint of CIS 1, 2, 3 on the first surface (CCD side) of the test chart, and CIS 1, 2 is output on the second surface (CIS side). Since the pattern is output at a position that is not a joint of CIS 1, 3 and 3C, the pattern is output at a position that is not a joint of CIS 1, 2, 3 on the second surface (CIS side), so that the test chart can be used with CIS 1, 2, 3. When the second surface is read, the density of the patch of the pattern can be accurately detected, and the second surface can be calibrated with high accuracy. The patterns on the first surface and the second surface are positioned relative to each other. Because there is a shift, even if there is a show-through, the density of the patch on the opposite side of the pattern will not be affected, so it is possible to perform high-precision calibration taking into account the positional relationship between the sensors on both sides. It becomes possible.

(Embodiment 2)
In the second embodiment, the description of the same parts as in the first embodiment is omitted, and only different points will be described. FIG. 7-1 is a diagram illustrating an example of a test chart on the first surface. A gradation pattern from the top to the bottom and a gradation pattern from the bottom to the top are output. This is because, for example, it is possible to distinguish the first surface and the second surface at the same time as the correction of the left / right difference, so that erroneous detection can be prevented even if the surface opposite to the intended surface is read by mistake. FIG. 7-2 is a diagram illustrating an example of a test chart on the second surface. The second surface is arranged so as to avoid the joint between the chart printing surface of the first surface and the CIS. Calibration can be performed with high accuracy by reading a test chart having such an arrangement.

  According to the second embodiment, a test chart is generated on the second surface of the test chart so as to avoid connection and adjacent positions for reading by the image sensor, and the test chart read by a single image sensor is output on the first surface. In addition, by obtaining optimum reading information, it is possible to perform optimum calibration for each reading unit at a time.

(Embodiment 3)
In the third embodiment, the description of the same parts as those in the first embodiment is omitted, and only different points will be described. In the third embodiment, the first reading unit 118 in FIG. 1 includes a plurality of CISs (CIS1 ₁ , CIS2 ₁ , CIS3 ₁ ) (hereinafter referred to as “first CIS”). The second reading unit 109 includes a plurality of CISs (CIS1 ₂ , CIS2 ₂ , CIS3 ₂ ) (hereinafter referred to as “second CIS”).

  8A and 8B show an example of the test chart of the third embodiment, and FIG. 8A shows an example of the first surface (surface to be read on the first CIS side) of the test chart. 8-2 shows an example of the second surface of the test chart (surface to be read on the second CIS side).

  As shown in FIGS. 8A and 8B, on the first surface and the second surface, a pattern is formed by avoiding the position of the joint of the first CIS and the second CIS, and the color plate The pattern is formed at a position away from the seam, and the K plate pattern is formed at a position near the seam. On the first surface, a K plate pattern is formed at a position corresponding to the second CIS joint, while on the second surface, a K plate pattern is formed at a position corresponding to the first CIS joint. It is desirable to form. As a result, it is possible to perform calibration with reduced deterioration of color mixing characteristics due to a drop in the accuracy of color plate correction caused by the arrangement of a plurality of CISs, and even when a large number of patterns are arranged, the paper layout Can be arranged efficiently. Here, the first reading unit 118 and the second reading unit 109 are configured by a plurality of CISs, but only one of them may be configured by a plurality of CISs.

  According to the third embodiment, at least one of the first reading unit 118 and the second reading unit 109 is configured by a plurality of image sensors, and the surface of the test chart corresponding to the reading unit configured by the plurality of image sensors. Then, the color plate pattern is formed at a position away from the position corresponding to the joints of the plurality of image sensors, and the K plate pattern is formed near the position corresponding to the joints of the plurality of image sensors. Therefore, it is possible to avoid the color pattern pattern of the test chart coming from the joint of the image sensor, and it is possible to prevent the deterioration of the gray reproducibility due to the color mixture.

(Embodiment 4)
In the fourth embodiment, the description of the same parts as in the first embodiment is omitted, and only different points will be described. In the fourth embodiment, the first reading unit 118 and the second reading unit 109 in FIG. 1 may be configured by either a single CCD or a plurality of CISs. FIG. 9 is a diagram illustrating an example of linearity characteristics of the first reading unit 118 and the second reading unit 109. In the figure, the horizontal axis indicates the patch number of the test chart, the vertical axis indicates the input value (white is “255” and black is “0”), and R_1, G_1, B_1 are the first reading unit 118, R_2, G_2, and B_2 indicate the second reading unit 109.

  In the example shown in the figure, the first reading unit 118 shows a substantially linear tendency, while the second reading unit 109 is distorted to the dark side. In the case of linear characteristics such as the first reading unit 118, as a test chart, calibration may be performed by outputting a patch with uniform gradation values and performing a complementary calculation. On the other hand, in the case of a linear characteristic such as the second reading unit 109, if the gradation values of the patches are made uniform, the complementary accuracy for distortion is reduced.

  Here, there is a method of shifting the complementation position by changing the tone value of the patch, but there is a problem that the accuracy of complementation is lowered due to individual differences. As a countermeasure, it is desirable to change the number of output patches and the patch density depending on the distortion rate. FIG. It is a figure which shows an example of the gradation value of an output patch. The tone values of the output patches may be the same for all CMYK versions, or may be set individually in consideration of the engine characteristics of each color. By performing calibration using the test charts of the first and second surfaces set as described above, it is possible to perform calibration with higher complement accuracy. The fourth embodiment may be implemented in combination with the other first to third embodiments. Further, a processing program that determines the number of output patches and the patch gradation value from the distortion by a program may be implemented.

  According to the fourth embodiment, the number of patches on the first and second surfaces of the test chart is determined according to the linear characteristics of the first reading unit 118 that reads the first surface and the second reading unit 109 that reads the second surface. Since the output is changed, optimal calibration can be performed.

(program)
Note that the image processing apparatus according to the present invention can be applied to a system including a plurality of devices (for example, a host computer, an interface device, a scanner, a printer, and the like). ) May be applied.

  Another object of the present invention is to supply a recording medium recording a program code of software for realizing the functions of the above-described image processing apparatus to the system or apparatus, and the computer of the system or apparatus (or CPU, MPU, It can also be achieved by the DSP) executing the program code stored in the recording medium. In this case, the program code read from the recording medium itself realizes the functions of the image processing apparatus described above, and the program code or the recording medium storing the program constitutes the present invention. Recording media for supplying the program code include FD, hard disk, optical disk, magneto-optical disk, CD-ROM, CD-R, magnetic tape, non-volatile memory, optical recording medium such as ROM, magnetic recording medium, optical Magnetic recording media and semiconductor recording media can be used.

  Further, by executing the program code read by the computer, not only the functions of the image processing apparatus described above are realized, but also an OS (operating system) operating on the computer based on the instruction of the program code. However, it is needless to say that a case where the function of the image processing apparatus described above is realized by performing part or all of the actual processing.

  In addition, after the program code read from the recording medium is written in a memory provided in a function expansion board inserted in the computer or a function expansion unit connected to the computer, the function expansion is performed based on the instruction of the program code. It goes without saying that the CPU or the like provided in the board or the function expansion unit performs part or all of the actual processing, and the above-described functions of the image processing apparatus are realized by the processing.

FIG. 1 is an overall configuration diagram of a digital image processing apparatus (MFP: Multifunction Peripheral) according to Embodiment 1 of the present invention. It is a figure which shows the schematic mechanical structure of a reader. It is a figure which shows the example of a rough arrangement | positioning of a 1st reading part. It is a figure which shows the example of schematic arrangement | positioning of a 2nd reading part. It is a figure which shows the structural example of an image processing apparatus. It is a figure which shows an example of the 1st surface of a test chart. It is a figure which shows an example of the 2nd surface of a test chart. It is a flowchart for demonstrating the procedure of a calibration. It is a figure for demonstrating (gamma) table. It is a figure which shows an example of the 1st surface of the test chart which concerns on Embodiment 2 of this invention. It is a figure which shows an example of the 2nd surface of the test chart which concerns on Embodiment 2 of this invention. It is a figure which shows an example of the 1st surface of the test chart which concerns on Embodiment 3 of this invention. It is a figure which shows an example of the 2nd surface of the test chart which concerns on Embodiment 3 of this invention. It is a figure which shows an example of the linearity characteristic of the 1st reading part which concerns on Embodiment 4, and a 2nd reading part. It is a figure which shows an example of the gradation value of an output patch.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reading apparatus 2 Image data processing apparatus 3 Bus control apparatus 4 HDD
5 CPU
6 Memory 7 Plotter I / F device 8 Plotter device 9 Operation display device 10 Line I / F device 11 External I / F device 12 B.
13 ROM
14 FAX
15 PC
17 Internal Speaker Device 21 Scanner γ Conversion Unit 22 Filter Processing Unit 23 Color Correction Unit 24 γ Correction Unit 25 Gradation Processing Unit 26 Test Chart Output Unit 31 γ Correction Processing Unit 32 Calibration Processing Unit 109 Second Reading Unit 118 First Reading part

Claims (8)

In an image processing apparatus that performs calibration by reading a test chart pattern,
A paper feeder for feeding the original,
A conveyance path through which the document fed by the sheet feeding unit is conveyed;
A first reading unit that reads an image of the first surface of the document from one side of the conveyance path;
A second reading unit that reads an image on the second surface of the document from the other side facing the one side through the conveyance path;
An image output means configured to print on both sides of the print medium, and to output an image on the print medium;
A test chart output means for causing the image output means to print out a test chart composed of a plurality of patch patterns on the print medium;
With
The image processing apparatus according to claim 1, wherein the test chart has different patterns on the first surface and the second surface. The first reading unit is composed of a single image sensor,
The second reading unit is composed of a plurality of image sensors,
The image processing apparatus according to claim 1, wherein a pattern is formed on a second surface of the test chart at a position that is not a joint of the plurality of image sensors.   The image processing apparatus according to claim 2, wherein a pattern is formed on a first surface of the test chart at a position corresponding to a joint of the plurality of image sensors. At least one of the first reading unit and the second reading unit includes a plurality of image sensors,
On the surface of the test chart corresponding to the reading unit composed of the plurality of image sensors, a color plate pattern is formed at a position away from a position corresponding to a joint of the plurality of image sensors, and the plurality of images The image processing apparatus according to claim 1, wherein a pattern of a K plate is formed near a position corresponding to a joint of the sensor.   2. The image processing apparatus according to claim 1, wherein the number of patches on the first surface and the second surface of the test chart is changed and output in accordance with characteristics of the first reading unit and the second reading unit. .   The image processing apparatus according to claim 5, wherein the characteristic is a linear characteristic. In an image processing method for performing calibration by reading a test chart pattern,
A step of reading, by a first reading unit, an image of a first surface of the original from one side of a conveyance path along which a document fed by a sheet feeding unit is conveyed;
A step of reading an image of the second surface of the original by a second reading unit from the other side facing the one side through the conveyance path;
Printing a test chart composed of a plurality of patches on a print medium; and
Including
The image processing method according to claim 1, wherein the test chart has different patterns on the first surface and the second surface. In a program installed in an image processing apparatus that reads and calibrates a test chart pattern,
On the computer,
A step of reading, by a first reading unit, an image of a first surface of the original from one side of a conveyance path along which a document fed by a sheet feeding unit is conveyed;
A step of reading an image of the second surface of the document from a second side facing the one side through the conveyance path by a second reading unit;
Printing a test chart composed of a plurality of patch patterns on the print medium and outputting the test chart,
The computer-executable program characterized in that the test chart has different patterns on the first surface and the second surface.