JP2010028725A - Image reader - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily increase resolution in an image reader having color and monochrome sensors. <P>SOLUTION: The image reader includes a color sensor and a monochrome sensor shifted by a half pitch in a horizontal scanning direction. The image reader generates first color image data based on input data from the color sensor, generates second color image data where a pixel has been shifted by a half pitch to the first color image data, based on input data from the monochrome sensor and those from the color sensor, and generates color image data by compositing the first and second color image data. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image reading apparatus.

An image forming apparatus such as a multifunction peripheral includes an image reading apparatus for reading an image formed on a document as image data.
Such an image reading apparatus generally includes a linear image sensor in which light receiving elements are arranged in the main scanning direction, and is formed on the original while relatively moving the linear image sensor and the original in the sub-scanning direction. An image is read as image data.

In such an image reading apparatus, the number of light receiving elements of the linear image sensor arranged in a predetermined range in the main scanning direction is usually a resolution. Therefore, in an image reading apparatus that requires high resolution, It is necessary to arrange a large number of light receiving elements depending on the range.
However, the number of light receiving elements that can be arranged in a predetermined range is limited due to mechanical limitations of the linear image sensor.

Therefore, a method has been proposed in which two linear image sensors are arranged so that the light receiving element pitch is shifted by half in the main scanning direction, and image data is generated by synthesizing data acquired from these two linear image sensors.
For example, in Patent Document 1, by disposing two linear image sensors only at locations corresponding to regions where high resolution is required, the resolution of a necessary region is increased and two linear image sensors are disposed. An image reading apparatus that suppresses an increase in cost has been proposed.
JP 2006-93820 A

  Incidentally, among image reading apparatuses capable of acquiring both color image data and monochrome image data, a color sensor which is a linear image sensor including a plurality of color light receiving elements for acquiring color data, and a monochrome image data. Some include a monochrome sensor that is a linear image sensor including a plurality of monochrome light receiving elements for acquiring data.

In an image reading apparatus including such a color sensor and a monochrome sensor, when the above-described high resolution technology is to be applied, a second linear image is obtained for each of the color sensor and the monochrome sensor. It is necessary to install a sensor, and the manufacturing cost of the image reading apparatus is significantly increased.
In particular, when a color sensor for red, a color sensor for green, and a color sensor for blue are provided as color sensors, it is necessary to add a total of four linear image sensors in addition to the monochrome sensor. Costs will increase significantly.

  The present invention has been made in view of the above-described problems, and an object thereof is to easily improve the resolution in an image reading apparatus including a color sensor and a monochrome sensor.

  The present invention adopts the following configuration as means for solving the above-described problems.

  According to a first aspect of the present invention, there is provided an image reading apparatus that reads an image of a document as image data, a color sensor including a plurality of color light receiving elements arranged at an equal pitch in the main scanning direction, and the color sensor in the main scanning direction. A monochrome sensor comprising a plurality of monochrome light-receiving elements arranged at the same pitch as the light-receiving elements, and wherein the monochrome light-receiving elements are arranged with a half-pitch offset with respect to the color light-receiving elements in the main scanning direction; A data generation unit that generates color image data using input data from the color light-receiving element and input data from the monochrome light-receiving element, and the data generation unit includes input data from the color light-receiving element. 1st color image data is generated based on the input data from the monochrome light receiving element and the input from the color light receiving element. Second color image data in which pixels are shifted by a half pitch with respect to the first color image data based on the data, and the first color image data and the second color image data are combined to generate the second color image data. A configuration for generating color image data is adopted.

  In a second aspect based on the first aspect, the data generation unit uses the input data from the monochrome light receiving element as the luminance data of the pixels of the second color image data, and the adjacent color light receiving elements. A configuration is adopted in which the average value of the chromaticity data included in the input data from the element is used as the chromaticity data of the pixels of the second color image data.

  According to a third aspect, in the first or second aspect, the color sensor includes a red color sensor, a green color sensor, and a blue color sensor arranged in the sub-scanning direction, and the red color sensor. The color light receiving element of the color sensor, the color light receiving element of the green color sensor, and the color light receiving element of the blue color sensor are arranged in alignment in the main scanning direction. Adopt the configuration.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, the monochrome sensor can output data at a higher speed than the color sensor.

According to the present invention, the first color image data is generated based on the input data from the color light receiving element, and the first color image is generated based on the input data from the monochrome light receiving element and the input data from the color light receiving element. Second color image data in which pixels are shifted by a half pitch with respect to the data is generated, and color image data is generated by combining the first color image data and the second color image data.
As described above, since the first color image data and the second color image data are shifted by a half pitch, the color image generated by combining the first color image data and the second color image data. The data is of high resolution.
That is, according to the present invention, it is possible to achieve high resolution of image data without adding a new linear image sensor in an image reading apparatus that includes both a color sensor and a monochrome sensor. Therefore, it is possible to easily improve the resolution in an image reading apparatus including a Lara sensor and a monochrome sensor.

  Hereinafter, an embodiment of an image reading apparatus according to the present invention will be described with reference to the drawings. In the following description, a multifunction peripheral will be described as an image forming apparatus including an image reading apparatus.

  FIG. 1 is a block diagram illustrating a functional configuration of the multifunction peripheral A according to the present embodiment. As shown in this figure, the multi-function device A of this embodiment includes a CPU (Central Processing Unit) 1, a ROM (Read Only Memory) 2, a RAM (Random Access Memory) 3, various sensor groups 4, and a printing paper transport unit 5. An image data storage unit 6, an image forming unit 7, a communication I / F unit 8, an operation display unit 9, and an image reading device 10.

  The CPU 1 is a control program stored in the ROM 2, detection signals input from the various sensor groups 4, image data stored in the image data storage unit 6, a personal computer or the like via the communication I / F unit 8. The overall operation of the multifunction peripheral A is controlled based on a print instruction signal received from an external device, image data for printing, an operation signal input from the operation display unit 9, and the like.

The ROM 2 is a non-volatile memory that stores a control program executed by the CPU 1 and other data.
The RAM 3 is a working memory used as a temporary storage destination of data when the CPU 1 executes a control program and performs various operations.
The various sensor groups 4 are various sensors necessary for the image forming operation such as a paper out detection sensor, a paper position detection sensor, a temperature sensor, and the like, and output various information detected by each to the CPU 1 as detection signals.

The printing paper transport unit 5 transports printing paper stored in a printing paper tray (not shown) to the image forming unit 7, a motor for driving the printing paper transport roller, and printing paper after image forming processing. It comprises a transport roller for transporting to a printing paper discharge tray (not shown), a motor for driving the transport roller, and the like.
The image data storage unit 6 is, for example, a flash memory, and stores image data of a document in response to a request from the CPU 1 and outputs image data of a predetermined document to the CPU 1.

The image forming unit 7 is controlled by the CPU 1 based on the image data of the original document stored in the image data storage unit 6 and the image data for printing received from an external device such as a personal computer. An image is formed on the printing paper by transferring the toner onto the conveyed printing paper and performing a fixing process on the toner.
The communication I / F unit 8 is an interface for performing communication between the multifunction peripheral A and an external device such as a personal computer, and is connected to the external device via a network such as a LAN (Local Area Network).

  The operation display unit 9 includes a start key, a stop key, a power key, a numeric keypad (numerical value input key), a touch panel, a clear key, and other various operation keys, and outputs an operation instruction for each key to the CPU 1. Under the control of the CPU 1, various screens are displayed on the touch panel.

Next, the image reading apparatus 10 will be described in detail with reference to FIG. FIG. 2 is a schematic configuration diagram illustrating a configuration of the image reading apparatus 10 of the multifunction peripheral A according to the present embodiment.
As shown in FIG. 2, the image reading apparatus 10 includes an automatic document conveyance type reading apparatus 11, a flat bed type reading apparatus 12, and an image reading circuit 13 (data generation unit).

  The automatic document conveyance type reading device 11 is a reading device that reads an image of a document as image data while automatically conveying a document one by one from a bundle of documents placed on a document tray 11a. Sensor) 11b, document discharge tray 11d, and lamp 11e.

  The document tray 11a is a table on which a document to be read is placed. The automatic document conveyance type reading device 11 is provided with a plurality of conveyance rollers (not shown) for conveying the documents one by one from the document bundle placed on the document tray 11a, and the documents are indicated by dotted lines by the conveyance rollers. It is transported along the document transport path and discharged to the document discharge tray 11d.

  The CIS 11b is a contact image sensor (linear image sensor) provided in the middle of the document transport path for reading an image of the document. The CIS 11 b outputs image data (analog signal) of an image read from the document to the image reading circuit 13.

In this embodiment, the CIS 11b includes a red CIS 20a, a green CIS 20b, a blue CIS 20c, and a black CIS 20d.
As shown in the schematic diagram of FIG. 3, in the red CIS 20a, red light receiving elements 21a (color light receiving elements) that receive red light and output it as a red signal (data) have a constant pitch d in the main scanning direction. It is arranged and configured.
The green CIS 20b includes green light receiving elements 21b (color light receiving elements) that receive green light and output green signals (data) arranged at a constant pitch d in the main scanning direction.
The blue CIS 20c includes blue light receiving elements 21c (color light receiving elements) that receive blue light and output blue signals (data) arranged at a constant pitch d in the main scanning direction.
The black CIS 20d includes black light receiving elements 21d (monochrome light receiving elements) that receive white light and output luminance signals (data) arranged at a constant pitch d in the main scanning direction. The black CIS 20d can output data at higher speed than the red CIS 20a, the green CIS 20b, and the blue CIS 20c which are color sensors.

These red CIS 20a, green CIS 20b, blue CIS 20c, and black CIS 20d are arranged at a constant interval D in the sub-scanning direction as shown in the schematic diagram of FIG.
The red CIS 20a, the green CIS 20b, and the blue CIS 20c are arranged such that the red light receiving element 21a, the green light receiving element 21b, and the blue light receiving element 21c are aligned in the main scanning direction.
On the other hand, in the black CIS 20d, the black light receiving element 21d is half of the pitch d (half pitch) in the main scanning direction with respect to the red light receiving element 21a, the green light receiving element 21b, and the blue light receiving element 21c. It is arranged so as to be displaced.

  The lamp 11e irradiates the original with illumination light (white light) having a constant intensity. The reflected light of the illumination light from the lamp 11e is read as an image signal by the CIS 11b.

  The flat bed type reading device 12 has a contact glass (not shown) as a document placement table fitted on the upper surface thereof, and reads an image of the document placed on the contact glass along the document conveyance path. , A mirror 12b, a condenser lens 12c, and a CCD (Charge Coupled Devices) 12d.

  The lamp 12a irradiates the surface of the document on the contact glass with illumination light (white light) having a constant intensity in a scanning manner, and the mirror 12b reflects the reflected light from the surface of the document toward the condenser lens 12c. To do.

  The condensing lens 12c condenses the reflected light of the surface of the document reflected by the mirror 12b on the light receiving surface of the CCD 12d.

The CCD 12 d converts the reflected light of the surface of the original collected by the condenser lens 12 c into image data (analog signal) and outputs it to the image reading circuit 13.
The CCD 12d also has a configuration having a color sensor and a monochrome sensor as in the CIS 11b. Specifically, the CCD 12d includes a red CCD instead of the red CIS 20a, a green CCD instead of the green CIS 20b, a blue CCD instead of the blue CIS 20c, and a black CIS 20d. A black CCD is provided.
The black CCD light receiving elements are arranged with a half-pitch deviation from the red CCD light receiving element, the green CCD light receiving element, and the blue CCD light receiving element in the main scanning direction.

  The image reading circuit 13 will be described in detail with reference to FIG. FIG. 4 is a functional block diagram showing a functional configuration of the image reading circuit 13. In FIG. 4, thick arrows indicate input / output of image data, and thin arrows indicate input / output of control signals.

  The image reading circuit 13 controls the automatic document conveyance type reading device 11 and the flatbed type reading device 12, converts the input data from the CIS 11b or the CCD 12d into a digital signal, and performs predetermined processing on the input data. Image data is generated by performing the above process.

  The image reading circuit 13 includes an A / D converter 13a, an image processing circuit 13c, an image memory circuit 13d, an image reading RAM 13e, an image reading ROM 13f, and an image reading CPU 13g.

  The A / D conversion unit 13a converts data (analog signal) input from the CIS 11b of the automatic document conveyance type reading device 11 or the CCD 12d of the flat bed type reading device 12 into a digital signal under the control of the image reading CPU 13g. The digital signal is output to the image processing circuit 13c.

The image processing circuit 13c generates image data from data input from the A / D conversion unit 13a under the control of the image reading CPU 13g.
Hereinafter, generation of high-resolution color image data and high-speed monochrome image data by the image processing circuit 13c will be described. In the following description, a case where image data is generated based on input data from the CIS 11b will be described. However, even in a case where image data is generated based on input data from the CCD 12d, the image processing circuit 13c The signal processing is the same.

  When generating high-resolution color image data, the image processing circuit 13c, as shown in the flowchart of FIG. 5, receives data input from the red light receiving element 21a of the red CIS 20a and green for the green CIS 20b. By combining the data input from the light receiving element 21b and the data input from the blue light receiving element 21c of the blue CIS 20c, a first color image composed of Lab data is generated (step S1). The Lab data is data representing luminance data (L) and chromaticity data (a, b) of each pixel.

The image processing circuit 13c also receives data input from the black light receiving element 21d of the black CIS 20d, data input from the red light receiving element 21a of the red CIS 20a, and green light receiving element 21b of the green CIS 20b. Based on the input data and the data input from the blue light receiving element 21c of the blue CIS 20c, second color image data in which pixels are shifted by a half pitch with respect to the first color image data is generated (step S2). ).
Specifically, in the image processing circuit 13c, the black light receiving element 21d is half pitch in the main scanning direction with respect to the color light receiving elements (red light receiving element 21a, green light receiving element 21b, and blue light receiving element 21c). Therefore, the data input from the black light receiving element 21d is the luminance data (L) of the pixel of the second color image data, and the chromaticity data included in the data input from the adjacent color light receiving elements. Is used as chromaticity data (a, b) of pixels of the second color image data to obtain second color image data.

In the second color image data generated in this way, each pixel is shifted by a half pitch with respect to the first color image data as described above.
Then, the image processing circuit 13c generates high-resolution color image data by combining the first color image data and the second color image data in which each pixel is shifted by a half pitch (step S3).

  In addition, when generating monochrome image data at high speed, the image processing circuit 13c outputs data from the black CIS 20d that can output data at a higher speed than the color sensors (red CIS 20a, green CIS 20b, blue CIS 20c). Monochrome image data is generated based only on the above.

  Then, the image processing circuit 13c outputs the image data generated as described above to the image memory circuit 13d.

  The image memory circuit 13d stores image data input from the image processing circuit 13c under the control of the image reading CPU 13g.

  The image reading RAM 13e is a working memory used as a temporary data storage destination when the image reading CPU 13g executes a control program to perform various operations.

The image reading ROM 13f is a non-volatile memory that stores a control program executed by the image reading CPU 13g and other data.
In this embodiment, the image reading ROM 13f stores a program for generating high-resolution color image data in the image processing circuit 13c, a program for generating monochrome image data at high speed, and the like. .

The image reading CPU 13g controls the overall operation of the image reading apparatus 10 based on a control program stored in the image reading ROM 13f.
The function of the image processing circuit 13c can be assigned to the image reading CPU 13g.

  In the MFP A of the present embodiment having such a configuration, an image based on the image data generated by the image reading device 10 in the image forming unit 7 is printed on the printing paper under the control of the CPU 1. The image data is transmitted via the communication I / F unit 8.

According to the image reading apparatus 10 provided in the multifunction peripheral A of the present embodiment as described above, the color sensors (from the CIS for red, the CIS for green, the CIS for blue, the CCD for red, the CCD for green, the CCD for blue) are used. First color image data is generated based on the input data, and pixels are half of the first color image data based on input data from the monochrome sensor (black CIS, black CCD) and input data from the color sensor. Second color image data having a pitch shift is generated, and the first color image data and the second color image data are combined to generate color image data.
As described above, since the first color image data and the second color image data are shifted by a half pitch, the color image generated by combining the first color image data and the second color image data. The data is of high resolution.
That is, according to the image reading apparatus 10 provided in the multifunction peripheral A of the present embodiment, the image reading apparatus including both the color sensor and the monochrome sensor has a high resolution of the image data without newly adding a linear image sensor. Can be realized. Therefore, it is possible to easily improve the resolution in an image reading apparatus including a Lara sensor and a monochrome sensor.

Further, in the image reading apparatus 10 provided in the multifunction peripheral A of the present embodiment, the black CIS 20d can output data at a higher speed than the color sensors (red CIS 20a, green CIS 20b, blue CIS 20c). .
For this reason, monochrome image data can be generated in a short time by generating monochrome image data based only on the input data from the black CIS 20d.

  Although the embodiments of the present invention have been described in detail with reference to the drawings, the specific configuration is not limited to the above-described embodiments, and design changes and the like can be made without departing from the scope of the present invention. .

For example, in the above-described embodiment, the configuration in which the image reading apparatus 10 and the operation display unit 9 are mounted on the multifunction peripheral A has been described.
However, the present invention is not limited to this, and can be used for an image forming apparatus such as a copying machine, a facsimile apparatus, or a scanner apparatus.

In the above embodiment, the configuration in which the image data stored in the image memory circuit 13 d is used for printing in the image forming unit 7 or transmission by the communication I / F unit 8 has been described.
However, the present invention is not limited to this, and the image data stored in the image memory circuit 13d may be stored in, for example, the image data storage unit 6 of the multifunction peripheral A.

1 is a functional block diagram of a multi-function peripheral including an image reading apparatus according to an embodiment of the present invention. 1 is a schematic configuration diagram of an image reading apparatus according to an embodiment of the present invention. It is a schematic diagram of CIS with which the image reading apparatus which is one Embodiment of this invention is provided. 1 is a functional block diagram of an image reading apparatus according to an embodiment of the present invention. 6 is a flowchart for generating high-resolution color image data in the image reading apparatus according to the embodiment of the present invention.

Explanation of symbols

  10 …… Image reading device, 11b …… CIS, 20a …… Red CIS (color sensor), 20b …… Green CIS (color sensor), 20c …… Blue CIS (color sensor), 20d …… Black CIS (monochrome sensor), 21a... Red light receiving element (color light receiving element), 21b... Green light receiving element (color light receiving element), 21c... Blue light receiving element (color light receiving element), 21d. ... Black light receiving element (monochrome light receiving element), 13 ... Image reading circuit (data generation unit)

Claims (4)

An image reading apparatus that reads an image of a document as image data,
A color sensor including a plurality of color light receiving elements arranged at equal pitches in the main scanning direction;
A plurality of monochrome light receiving elements arranged at the same pitch as the color light receiving elements in the main scanning direction, and the monochrome light receiving elements are shifted by a half pitch with respect to the color light receiving elements in the main scanning direction; A monochrome sensor to be arranged;
A data generation unit that generates color image data using input data from the color light-receiving element and input data from the monochrome light-receiving element;
The data generation unit generates first color image data based on input data from the color light receiving element, and based on input data from the monochrome light receiving element and input data from the color light receiving element. Second color image data in which pixels are shifted by the half pitch with respect to the first color image data is generated, and the first color image data and the second color image data are combined to generate the color image data. An image reading apparatus.   The data generation unit uses the input data from the monochrome light receiving element as luminance data of the pixels of the second color image data, and calculates an average value of chromaticity data included in the input data from the adjacent color light receiving elements. The image reading apparatus according to claim 1, wherein chromaticity data of pixels of the second color image data is used. The color sensor includes a red color sensor, a green color sensor, and a blue color sensor arranged in the sub-scanning direction,
The color light receiving element of the red color sensor, the color light receiving element of the green color sensor, and the color light receiving element of the blue color sensor are arranged in alignment in the main scanning direction. The image reading apparatus according to claim 1, wherein the image reading apparatus is an image reading apparatus. The image reading apparatus according to claim 1, wherein the monochrome sensor is capable of outputting data at a higher speed than the color sensor.

Images