JP2009089173A - Image processor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image processor or the like capable of obtaining shading data appropriate for individual machine platforms with a simple configuration. <P>SOLUTION: A line sensor 21 reads a shading plate 13 so as to generate an analog signal (for image data for position correction, or for shading data). An AFE 22 converts the analog signal output from the line sensor 21 to digital data, and outputs the data. A shading correction part 23 performs shading correction of the image data output from the AFE 22 when a manuscript has been read by using normal shading data stored in a storage part 26. The storage part 26 stores the correction data, the image data for position correction, and the shading data. The control part corrects a home position of a first carriage 15a or a second carriage 15b by using the image data with a read position detection mark. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image processing apparatus that reads a document placed on a document placement table, and more particularly to an image processing apparatus that acquires shading data used to correct (shading correction) the luminance value and the like of a read document. .

  In general, in an image processing apparatus having a function of optically reading a document placed on a document placement table, in particular, Flat Bed Scanner (hereinafter referred to as “FBS”), in order to correct distortion of an optical system, Shading correction is performed. This “shading correction” is correction of a phenomenon in which the amount of received light increases at the central portion and decreases at the end portion. More specifically, a shading plate (also referred to as a “white reference plate”) provided along the main scanning direction is read to acquire shading data, and the luminance value of the document is corrected using the shading data. Is.

Conventionally, a technique for determining a home position of an optical system unit called a “carriage” when acquiring shading data has been disclosed (see, for example, Patent Document 1 or Patent Document 2).
JP 2004260642 A JP 2001-5119 A

  However, in the above prior art, since light is reflected in the vicinity of the end surface of the document table, it is difficult to obtain normal shading data, while there is a demand for downsizing (that is, narrowing the shading plate width). . For this reason, there is a problem that the positional accuracy of the carriage must be improved while taking into account variations in individual machine bases.

  It should be noted that the shading plate is placed on the glass of the document table, and that the shading plate is placed on the edge of the glass (that is, the edge of the shading plate is the glass of the document table). It is provided so as to be located in the same plane as the edge or substantially in the same plane).

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an image processing apparatus and the like that can acquire appropriate shading data corresponding to each machine base with a simple configuration or processing. And

  In order to achieve the above object, an image processing apparatus according to the present invention is an image processing apparatus having a carriage for optically reading an image that moves in the sub-scanning direction, on a shading plate or around a shading plate. Using the correction image acquisition unit that reads the position detection mark provided in the image acquisition unit to acquire image data for position correction, the correction data that is defined in advance, and the acquired image data for position correction, A position correction unit that corrects a reading position on the carriage, and a shading data acquisition unit that acquires shading data using the carriage at the corrected position.

  Accordingly, it is possible to obtain appropriate shading data corresponding to each machine base with a simple configuration or processing.

  In addition, the present invention can be realized not only as an image processing apparatus but also as an image processing method using characteristic constituent means in the image processing apparatus as steps, or as a program for causing a computer to execute these steps. You can also.

  According to the present invention, it is possible to provide an image processing apparatus or the like that can acquire appropriate shading data corresponding to each machine base with a simple configuration or processing.

  Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings. In addition, although this invention is demonstrated using the following embodiment and attached drawing, this is for the purpose of illustration and this invention is not intended to be limited to these.

  The image processing apparatus according to the present invention is an apparatus capable of acquiring appropriate shading data corresponding to each machine base with a simple configuration or processing.

  FIG. 1 is an external view of an image processing apparatus 100 according to the present invention. 2 is an enlarged external view of the document reading unit of the image processing apparatus 100 shown in FIG. FIG. 2 shows a document table 10, a document cover 11, a document table glass 12, a shading plate 13, an operation panel 14, and the like. The shading plate 13 is actually installed (attached or the like) on the upper surface of the document table glass 12 (see FIG. 4 described later).

  FIG. 3 is an example of a hardware configuration diagram of the image processing apparatus 100. An image processing apparatus 100 shown in FIG. 3 is an MFP (Multi Function Peripherals) having a function of reading a document. The image processing apparatus 100 includes a CPU 110, a ROM 111, a RAM 112, a modem 113, an NCU (Network Control Unit) 114, an operation panel 115, a display 116, a scanner 117, a printer 118, and a LAN I / F (LAN Inter-Face) 119. .

  The CPU 110 controls each function of the image processing apparatus 100 by executing a control program 111 a stored in the ROM 111.

  The ROM 111 is a read-only memory that holds the control program 111a and the like. The ROM 111 may store correction data described later. Further, if the ROM 111 is a rewritable ROM, shading data described later may be stored.

  The RAM 112 is a memory used as a work area used when the CPU 110 executes the control program 111a, and is a volatile readable / writable memory that temporarily holds image data read by the scanner 117. Further, the RAM 112 stores image data for position correction and shading data used for shading correction (in addition, the RAM 112 may store correction data described later).

  The modem 113 is a G3 fax modem or the like that modulates image data transmitted by facsimile or demodulates image data transmitted from the outside by facsimile.

The NCU 114 is a line terminating device connected to the PSTN 105.
The operation panel 115 corresponds to the operation panel 14 in FIG. 2 and is a panel that receives an operation from the operator.

  The display 116 is a liquid crystal display (LCD) or the like, and is used for dialogue with an operator or displays the operation state of the image processing apparatus 100. The display 116 may be configured as a part of the operation panel 115.

  The scanner 117 is an image reading device that generates image data by reading the content of a document with a CCD or the like when transmitting a facsimile or copying and outputting to the printer 118, and has a function of performing shading correction. .

  The printer 118 is a printing device, and outputs and prints the content read from the scanner 117, and outputs and prints image data received from the other facsimile devices via the PSTN 105 and the NCU 114 or the modem 113.

  A LAN I / F 119 is a communication adapter that connects the image processing apparatus 100 and the LAN 106.

  FIG. 4 is a configuration diagram schematically showing a main configuration inside the scanner 117 in the image encoding device 100. As shown in FIG. 4, the scanner 117 includes a first carriage 15 a including a light source 16 for irradiating light on a document and a reflection mirror 17 for guiding reflected light from the document in a predetermined direction, and reflection mirrors 18 and 19. A second carriage 15b including Further, the scanner 117 includes a condenser lens 20 that converges the reflected light guided by the second carriage 15b and a line sensor 21 that converts the converged light into an electrical signal. Further, a shading plate 13 formed by applying a white tape or painting white on the upper surface of the scanner 117 near the end surface of the platen glass 12 has a longitudinal direction in the main scanning direction (x direction in FIG. 2). Is arranged as. The shading plate 13 is read by the line sensor 21, and image data which is shading data is generated.

  FIG. 5 is a block diagram showing a functional configuration of the scanner 117. As shown in FIG. 5, the scanner 117 includes a line sensor 21, an AFE (Analog Front End) 22, a shading correction unit 23, a gamma correction unit 24, an image processing unit 25, a storage unit 26, and a control unit (not shown). I have.

  The line sensor 21 sequentially reads the shading plate 13 or the document for each scanning line (one reading line) according to an instruction from the control unit, and generates an analog signal.

  The AFE 22 converts the analog signal generated by the line sensor 21 into digital data, and generates position correction image data, shading data, or document image data. Each luminance value of the digital data generated by the AFE 22 is represented by 9 bits (that is, 0 to 511). The line sensor 21 and the AFE 22 are examples of a corrected image acquisition unit and an image acquisition unit in the claims.

  The shading correction unit 23 performs shading correction on the digital data output from the AFE 22 at the time of document reading using the shading data stored in the storage unit 26 and outputs the result.

  The gamma correction unit 24 performs gamma correction on the image data based on predetermined input / output characteristics. The gamma correction unit 24 may be used for image quality adjustment.

  The image processing unit 25 performs image processing such as smoothing, edge enhancement, and enlargement / reduction on the image data output from the gamma correction unit 24 with a predetermined threshold.

  The storage unit 26 corresponds to the ROM 111 or the RAM 112 in FIG. 3 and stores correction data, image data for position correction, and shading data (that is, regular shading data). Here, “correction data” refers to temporary shading data used when recognizing image data of a position detection mark. This correction data is shading data common to each machine base at the time of shipment from the factory. In order to obtain shading data that matches the characteristics of each machine base, it is necessary to actually read the shading plate 13 provided on the platen glass 12. At this time, as described above, if the shading plate 13 near the end surface of the platen glass 12 is read in a state where the position control accuracy of the carriage (the first carriage 15a or the second carriage 15b) is low, the end surface reflection causes the reading. A situation occurs in which normal shading data cannot be acquired. Therefore, in the present invention, after the position detection mark in which the relative position with respect to the shading plate 13 is defined is read in advance and the position of the carriage is corrected, it is correct at a position that is not affected by the end face reflection of the document table glass 12. Get shading data.

  The control unit corresponds to the CPU 110 in FIG. 3 and controls the line sensor 21 to the storage unit 26. Further, the control unit corrects the home position of the first carriage 15a or the second carriage 15b by using (for example, comparing) the correction data and the position correction image data. Specifically, since the relative positional relationship between the shading plate 13 and the position detection mark is fixed, the control unit determines the position in the y direction where the position detection mark first appears from the image data of the read position detection mark in pixel units. Compare. Further, the control unit converts the difference in the number of pixels, which is the comparison result, into the number of steps of the stepping motor when moving the first carriage 15a or the second carriage 15b, and performs the above correction. Note that the control unit may update the correction data stored in the storage unit 26 with the generated image data for position correction. The control unit is an example of a position correction unit in the claims.

6A to 6C are diagrams showing an example of the shading plate 13 according to the present invention.
FIG. 6A is an example of the shading plate 13 when two position detection marks are provided near both ends in the main scanning direction. When generating the first image data, it is read including the position detection mark, and when generating the final shading data (second image data), the inside of the effective reading area is read.

  FIG. 6B is an example of the shading plate 13 when one position detection mark is provided in the sub-scanning direction (y direction in FIG. 2). Further, FIG. 6C is a modified example of FIG. 6B and is an example of the shading plate 13 when a “notch” is provided as one position detection mark in the sub-scanning direction. In this case, the color density difference between the shading plate 13 and the document table 10 behind (that is, provided around the shading plate 13) is increased (for example, a black background is used for the white shading plate 13). Thus, the position detection mark described above can be made unnecessary.

Next, the operation of the image processing apparatus 100 configured as described above will be described.
FIG. 7 is a flowchart showing a flow of processing for acquiring shading data in the image processing apparatus 100.

  First, the control unit specifies correction data defined in advance (specifically, the correction data stored in the storage unit 26 is read) (S100).

  Next, the control unit reads the shading plate 13 to which the position detection mark is attached to generate image data for position correction (S102), and the image processing unit 25 processes the read image data. The position correction amount is calculated (S104). Thereafter, the control unit corrects the position of the first carriage 15a or the second carriage 15b using the calculated position correction amount (S106). At this time, the control unit instructs the shading correction unit 23 to store the generated image data for position correction in the storage unit 26.

  Further, the control unit reads the shading plate 13 again, generates final shading data (S108), and controls to store in the storage unit 26.

  As described above, according to the image processing apparatus 100 according to the present invention, since the carriage home position is corrected for each machine to absorb the variation between the machines, more appropriate shading data can be acquired. It becomes possible.

  The present invention can be used for an image processing apparatus having a function of optically reading a document, such as a scanner and an MFP.

1 is an external view of an image processing apparatus according to the present invention. 1 is an enlarged external view of a document reading unit of an image processing apparatus according to the present invention. It is an example of the hardware block diagram of the image processing apparatus which concerns on this invention. FIG. 2 is a diagram schematically illustrating a main configuration inside a scanner in the image processing apparatus according to the present invention. 2 is a block diagram illustrating a functional configuration of a scanner in the image processing apparatus according to the present invention. FIG. It is a figure which shows an example of the shading plate which concerns on this invention. It is a figure which shows an example of the shading plate which concerns on this invention. It is a figure which shows an example of the shading plate which concerns on this invention. It is a flowchart which shows the flow of the process which acquires the shading data in the image processing apparatus which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Original stand 11 Original cover 12 Original plate glass 13 Shading plate 14 Operation panel 15a 1st carriage 15b 2nd carriage 16 Light source 17, 18, 19 Reflection mirror 20 Condensing lens 21 Line sensor 22 AFE
23 Shading Correction Unit 24 Gamma Correction Unit 25 Image Processing Unit 26 Storage Unit 100 Image Processing Device 110 CPU
111 ROM
112 RAM
113 Modem 114 NCU
115 Operation Panel 116 Display 117 Scanner 118 Printer 119 LAN I / F

Claims (6)

An image processing apparatus having a carriage for optically reading an image, moving in the sub-scanning direction,
A correction image acquisition unit that reads position detection marks provided on or around the shading plate and acquires image data for position correction;
A position correction unit that corrects a reading position in the carriage, using correction data defined in advance and the acquired image data for position correction;
An image processing apparatus comprising: a shading data acquisition unit that acquires shading data using the carriage at the corrected position. The image processing apparatus further includes:
An image acquisition unit for optically reading a document and acquiring image data;
The image processing apparatus according to claim 1, further comprising: an image shading correction unit that performs shading correction on the acquired image data using the acquired shading data. The position correction unit is
A positional deviation in the y direction where the position detection mark appears in the image data for position correction is calculated in units of pixels, and the positional deviation is converted into the number of steps of the stepping motor when moving the carriage. The image processing apparatus according to claim 1, wherein the home position is corrected. The shading plate is
The image processing apparatus according to claim 1, wherein the position detection marks are attached to two locations near both ends in the main scanning direction or one location in the sub-scanning direction. The image processing apparatus according to claim 4, wherein the position detection mark in the sub-scanning direction is a notch. An image processing method in an image processing apparatus having a carriage for optically reading an image that moves in a sub-scanning direction,
A correction image acquisition step of reading position detection marks provided on or around the shading plate and acquiring image data for position correction;
A position correcting step for correcting a reading position in the carriage using pre-defined correction data and the acquired image data for position correction;
A shading data acquisition step of acquiring shading data using the carriage at the corrected position.

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