JP2010213159A - Light source device, light source unit, image reader, image forming apparatus, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To select a conversion coefficient corresponding to variance in chromaticity among a plurality of light emitting components mounted on a light source device. <P>SOLUTION: A look-up table (LUT) parameter storage unit 44 stores a plurality of LUT parameters for correcting chromaticity of image data read by an image read unit 30 by chromaticity areas as chromaticity variance ranges of white LEDs 36 used as the light source. A chromaticity area decision unit 43 determines chromaticity areas of a plurality of white LEDs 36 based upon RGB image data which has been read by the image read unit 30 when an LED 60 for chromaticity area decision making different in chromaticity from the white LEDs 36 is turned on to irradiate a white reference plate 16 with light, and also has been subjected to position correction etc., by a position correction unit 42. A parameter selection unit 45 selects an LUT parameter corresponding to a decision result of the chromaticity area decision unit 43 out of the plurality of LUT parameters stored in the LUT parameter storage unit 44. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a light source device, a light source unit, an image reading device, an image forming device, and a program.

  In Patent Document 1, a theoretical color range that does not depend on a specific device and a color reproduction range that depends on a device are obtained from a theoretical formula using an equation function and a spectral reflection distribution of an ideal specific color, and a read image is obtained. An image processing apparatus that performs data conversion processing is disclosed.

Japanese Patent No. 3143508

  An object of the present invention is to provide a light source device, a light source unit, an image reading device, an image forming apparatus, and a program capable of selecting a conversion coefficient according to chromaticity variations of a plurality of light emitting components mounted on the light source device. Is to provide.

[Image reading device]
According to a first aspect of the present invention, there is provided a light source device having a plurality of light emitting components functioning as a light source and a light emitting component for discrimination having a chromaticity different from that of the light emitting component, and an original image is irradiated by the light source device. Reading means for reading image data,
A determination unit that determines a chromaticity range of the plurality of light-emitting components based on image data read by the reading unit when the light-emitting component for lighting is turned on and a reference color region is irradiated with light;
Storage means for storing a plurality of conversion coefficients for correcting the chromaticity of the image data read by the reading means;
A selection means for selecting a conversion coefficient corresponding to a determination result in the determination means from a plurality of conversion coefficients stored in the storage means;
An image reading apparatus comprising: a correction unit that corrects the chromaticity of the image data read by the reading unit using the conversion coefficient selected by the selection unit.

  The present invention according to claim 2 is the image reading apparatus according to claim 1, wherein the conversion coefficient is a conversion coefficient for converting image data of a certain color system into image data of another color system.

[Image forming apparatus]
According to a third aspect of the present invention, there is provided a light source device having a plurality of light emitting components functioning as a light source and a light emitting component for discrimination having a chromaticity different from that of the light emitting component, and an original image is irradiated by the light source device. A reading means for reading the image data, and a chromaticity range of the plurality of light emitting components based on the image data read by the reading means when the light emitting component for discrimination is turned on and the reference color region is irradiated with light. Determination means for determining the image data, storage means for storing a plurality of conversion coefficients for correcting the chromaticity of the image data read by the reading means, and a plurality of conversion coefficients stored in the storage means The chromaticity of the image data read by the reading unit is compensated by using a selection unit that selects a conversion coefficient corresponding to the determination result in the determination unit and the conversion coefficient selected by the selection unit. An image reading apparatus provided with a correction means for,
And an image output unit that outputs an image based on image data read by the image reading device.

[Light source device]
According to a fourth aspect of the present invention, there is provided a light source device in which a plurality of light emitting components functioning as a light source and a determination light emitting component having a different chromaticity are mounted.

  The present invention according to claim 5 is the light source device according to claim 4, wherein the light-emitting component for determination is mounted on the same line as the plurality of light-emitting components functioning as a light source on the light source device.

[Light source unit]
According to a sixth aspect of the present invention, there is provided a light source device in which a plurality of light emitting components functioning as a light source and a light emitting component for discrimination having a different chromaticity are mounted,
A light guide member for guiding light from the light source device;
It is a light source unit provided with the fixing member which fixes the positional relationship of the said light source device and the said light guide member.

[program]
According to the seventh aspect of the present invention, the light-emitting component for determination is turned on for a light source device in which a plurality of light-emitting components functioning as a light source and a light-emitting component for determination different in chromaticity from the light-emitting component are mounted. Steps,
Determining a chromaticity range of the plurality of light-emitting components based on image data read when the reference color region is irradiated with light from the light-emitting light-emitting component for determination,
Selecting a conversion coefficient corresponding to the determined chromaticity range from a plurality of conversion coefficients;
A program for causing a computer to execute a step of correcting chromaticity of read image data using a selected conversion coefficient.

  According to the first aspect of the present invention, it is possible to provide an image reading apparatus capable of selecting a conversion coefficient corresponding to variations in chromaticity of a plurality of light emitting components mounted on a light source device.

  According to the invention of claim 2, in addition to the effect obtained by the invention of claim 1, the color of the image data is converted when the image data read by the reading means is converted into image data of a different color system. An image reading apparatus capable of correcting the degree can be provided.

  According to the third aspect of the present invention, it is possible to provide an image forming apparatus capable of selecting a conversion coefficient corresponding to variation in chromaticity of a plurality of light emitting components mounted on a light source device.

  According to the fourth aspect of the present invention, it is possible to provide a light source device capable of selecting a conversion coefficient according to variations in chromaticity of a plurality of light emitting components mounted on the light source device.

  According to the fifth aspect of the present invention, in addition to the effect obtained by the fourth aspect of the invention, the light from the light-emitting component for discrimination is transmitted through the same path as the light from the plurality of light-emitting components functioning as a light source. Thus, it is possible to provide a light source device that can reach the reading means.

  According to the sixth aspect of the present invention, it is possible to provide a light source unit capable of selecting a conversion coefficient according to chromaticity variations of a plurality of light emitting components mounted on a light source device.

  According to the seventh aspect of the present invention, it is possible to provide a program capable of selecting a conversion coefficient corresponding to variations in chromaticity of a plurality of light emitting components mounted on a light source device.

1 is a diagram illustrating a configuration of an image reading apparatus according to an embodiment of the present invention. FIG. 3 is a diagram illustrating a positional relationship between a main body unit 20 and a white reference plate 16 of an image reading apparatus according to an embodiment of the present invention. It is a figure which shows the structure of the LED array board | substrate 37 in the image reading apparatus of one Embodiment of this invention. It is a figure for demonstrating an example of the setting of a chromaticity area. It is a figure which shows an example of the correspondence of chromaticity area of white LED36, and LED60 for chromaticity area discrimination | determination. It is a figure which shows the light source unit 70 containing the LED array board | substrate 37 shown in FIG. 6 is a flowchart illustrating an operation when setting a lookup table parameter in the image reading apparatus according to the embodiment of the present invention. It is a flowchart which shows this operation | movement.

  Next, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram of an image reading apparatus according to an embodiment of the present invention.

  As shown in FIG. 1, the image reading apparatus according to the present embodiment includes a lid 10 and a main body 20.

  The lid 10 includes a document tray 17, a document separation roll 11 provided at a standby position of the document 50 placed on the document tray 17, a document transport roll 12 that transports the document, and a reading roll 13. , A discharge roll 14 and a white reference plate 16 (reference color region). These document separation roll 11, document transport roll 12, reading roll 13, discharge roll 14 and the like constitute a document transport means for transporting a plurality of pages of documents to a predetermined document reading position sequentially.

  The white reference plate 16 has a white reflecting surface that serves as a reference when performing signal level correction and light source colorimetry, and is disposed beside the platen glass 21.

  The main body unit 20 includes a platen glass 21, an image reading unit 30 for reading an image of a document conveyed to a document reading position by a document conveying unit for each page, an A / D conversion unit 41, and a position correction unit 42. A chromaticity area (chromaticity range) determination unit 43, a lookup table storage unit 44, a parameter selection unit 45, and a color space conversion correction unit 46.

  The image reading unit 30 includes an LED array substrate 37 on which a plurality of white LEDs 36 are mounted, a light guide 31 for guiding light from the plurality of white LEDs 36, reflection mirrors 32 and 33, and an imaging lens 34. And a photoelectric conversion element 35 such as a CCD.

  The image reading unit 30 is provided on a carriage (not shown) and can move in the sub-scanning direction. Therefore, when reading an image of a document placed on the platen glass 21, the image reading unit 30 can read the document while moving in the sub-scanning direction. Further, when reading an image of a document placed on the document tray 17, the image reading unit 30 is transported from the document tray 17 by moving to the document reading position where the reading roll 13 is provided. The document image can be read sequentially.

  FIG. 2 is a diagram illustrating a positional relationship between the main body 20 and the white reference plate 16 of the image reading apparatus according to the present embodiment. In this embodiment, the case where the white reference plate 16 is installed beside the platen glass 21 is described. However, the surface on which the white reference plate 16 contacts the platen glass 21 of the main body 20 of the lid 10. In some cases, it is installed in the main scanning direction. In the case where the white reference plate 16 is installed on the lid 10, the white reference plate 16 is lifted together with the lid 10 when the lid 10 is lifted. Although it cannot be located on the platen glass 21, the white reference plate 16 is shown in FIG. 2 for convenience of explanation. Even when the white reference plate 16 is installed on the lid 10, as shown in FIG. 3, when the lid 10 is closed, the white reference plate 16 contacts the platen glass 21 in the main scanning direction. is doing.

  Next, the configuration of the LED array substrate 37 will be described with reference to FIG. A plurality of white LEDs 36 (light emitting components) that function as light sources are mounted on the LED array substrate 37. Further, on the same line (line) on which the plurality of white LEDs 36 are mounted on the LED array substrate 37, the chromaticity is different from the white LEDs 36 and is used for chromaticity area discrimination indicating the variation range of the chromaticity of the white LEDs 36. LED 60 is mounted. Here, the case where four chromaticity area determination LEDs 60 are mounted on the LED array substrate 37 will be described, but the present invention can be realized by using at least one chromaticity area determination LED 60. It is.

  The chromaticity area determination LED 60 is not lit during normal image reading, but is lit only during various adjustments such as when the image reading apparatus is activated.

  In general, a white LED is configured by surrounding a blue light emitting point with a yellow phosphor. Therefore, white LEDs vary greatly in chromaticity due to this blue variation and the balance of the yellow phosphor. Therefore, manufacturers of white LEDs classify the chromaticities of the produced white LEDs into several chromaticity ranges, and ship with rank designation corresponding to the chromaticity ranges. For example, as shown in FIG. 4, the white LED is shipped in a state where any one of the areas A to D is designated on the manufacturer side.

  Therefore, when the LED array substrate 37 is produced, the chromaticity area determination LED 60 having a color corresponding to the chromaticity area specified for the white LED 36 mounted on the LED array substrate 37 is selected and mounted on the LED array substrate 37. To do. Here, it is assumed that all the white LEDs 36 to be mounted on one LED array substrate 37 are those in which the same chromaticity area is designated.

  An example of the correspondence between the chromaticity area of the white LED 36 and the chromaticity area determination LED 60 is shown in FIG.

  Referring to FIG. 5, it is set that blue, green, orange, and red LEDs are used as the chromaticity area determination LEDs 60 for the areas A to D that are the chromaticity areas of the white LED 36. Recognize. That is, for example, when the chromaticity area of the white LED 36 mounted on the LED array substrate 37 is area A, a blue LED is selected as the chromaticity area determination LED 60 and mounted on the LED array substrate 37.

  The chromaticities of the blue, green, orange, and red LEDs used as the chromaticity area determination LED 60 are indicated by coordinates 61 to 64 on the chromaticity diagram of FIG. As shown in FIG. 4, the chromaticity of the white LED 36 used as the light source and the chromaticity of the blue, green, orange, and red LEDs used as the chromaticity area determination LED 60 can be easily distinguished from each other. Thus, a color difference of a certain amount or more is provided.

  The LED array substrate 37 thus configured and the optical components such as the light guide 31 are configured to be detachable as a light source unit in a state where the positional relationship is fixed by a fixing member. An example of the light source unit 70 including the LED array substrate 37 is shown in FIG.

  Next, the configuration of the A / D conversion unit 41, the position correction unit 42, the chromaticity area determination unit 43, the lookup table storage unit 44, the parameter selection unit 45, and the color space conversion correction unit 46 illustrated in FIG. 1 will be described. To do.

  The A / D conversion unit 41 converts analog RGB image data obtained by the photoelectric conversion element 35 of the image reading unit 30 into digital RGB image data.

  The position correction unit 42 performs position correction on the digital RGB image data converted by the A / D conversion unit 41 to correct a reading line position shift in the sub-scanning direction. In addition, the position correction unit 42 includes a shading correction function for correcting output fluctuations caused by uneven illuminance in the main scanning direction of the optical system, uneven sensitivity for each sensor pixel, temporal fluctuations in the amount of illumination light, and the like. Also good.

  The chromaticity area determination unit 43 is read by the image reading unit 30 when the chromaticity area determination LED 60 is turned on and the white reference plate 16 is irradiated with light, and the position correction unit 42 performs position correction and the like. Based on the RGB image data, the chromaticity areas of the plurality of white LEDs 36 are determined.

  The chromaticity area determination unit 43 determines the color of the chromaticity area determination LED 60 based on the output balance of the R, G, and B image signals of the RGB image data, and determines the determined chromaticity area determination. The chromaticity area of the plurality of white LEDs 36 is determined based on the color of the LED 60. For example, if the chromaticity area determination unit 43 determines that the color of the RGB image data when the chromaticity area determination LED 60 is turned on is green, the chromaticity area of the white LED 36 being used is the area B. It is determined that

  The look-up table parameter storage unit 44 stores a plurality of look-up table (LUT) parameters for correcting the chromaticity of the image data read by the image reading unit 30. The look-up table parameter refers to image data in which RGB image data is represented by L * a * b * (hereinafter abbreviated as Lab), which is a color system defined by the CIE (International Commission on Illumination). This is a conversion coefficient for conversion to.

  The lookup table parameter storage unit 44 stores four lookup table parameters corresponding to the areas A to D shown in FIGS.

  When generating this look-up table parameter, first, a chromaticity as a central value is set in the entire chromaticity range of the white LED as a light source, and a reference look based on the chromaticity of the central value is set. Generate uptable parameters. Then, using this chromaticity as the center value as a reference point, a new creation point is set in a chromaticity area where the color difference from this reference point exceeds the allowable range, and the color difference from the reference point of this creation point is within the allowable range. Generate a lookup table parameter such that In this way, corresponding look-up table parameters are generated for the chromaticity areas of the white LEDs.

  The parameter selection unit 45 selects a lookup table parameter corresponding to the determination result in the chromaticity area determination unit 43 from a plurality of lookup table parameters stored in the lookup table parameter storage unit 44. That is, when the chromaticity area determination unit 43 determines that the chromaticity area of the white LED 36 mounted on the LED array substrate 37 is the area B, the parameter selection unit 45 is generated corresponding to the area B. Select the lookup table parameter.

  The color space conversion correction unit 46 sets the lookup table parameter selected by the parameter selection unit 45 as a parameter to be used, is read by the image reading unit 30, and passes through the A / D conversion unit 41 and the position correction unit 42. The input RGB image data is converted into Lab image data, and the chromaticity of the image data is corrected.

  That is, in the present embodiment, the color space conversion correction unit 46 corrects the chromaticity variation of the white LEDs 36 mounted on the LED array substrate 37 when converting the RGB image data into the Lab image data. However, this color space conversion and chromaticity variation correction may be executed separately in different processes.

Next, the operation of the image reading apparatus of this embodiment will be described in detail with reference to the drawings.
FIG. 7 is a flowchart showing the operation when setting the look-up table parameters in the image reading apparatus of this embodiment.

  First, the carriage is moved to move the image reading unit 30 to below the white reference plate 16 (step S101). Then, the LED array substrate 37 is controlled to turn on the chromaticity area determination LED 60 among the mounted LEDs (step S102). Here, only the chromaticity area determination LED 60 is lit and the white LED 36 is not lit. However, if the whiteness of the chromaticity area determination LED 60 can be determined, the chromaticity area determination LED 60 and the white LED 36 are displayed. Alternatively, the chromaticity area may be determined in a state where the lights are turned on simultaneously.

  The RGB image data read by the image reading unit 30 when the light from the lit chromaticity area determination LED 60 is irradiated on the white reference plate 16 is converted into digital data by the A / D conversion unit 41, and position correction is performed. Position correction is performed in the unit 42. Then, the chromaticity area determination unit 43 determines the chromaticity area of the white LED 36 mounted on the LED array substrate 37 based on this image data (step S103).

  Then, the parameter selection unit 45 selects the LUT parameter corresponding to the determination result in the chromaticity area determination unit 43 from the plurality of lookup table parameters (LUT parameters) stored in the lookup table parameter storage unit 44. (Step S104).

  Then, the LUT parameter selected by the parameter selection unit 45 is set in the color space conversion correction unit 46 (step S105). The color space conversion correction unit 46 converts the RGB image data from the position correction unit 42 into Lab image data using the set LUT parameter, and outputs it.

  The processing shown in FIG. 7 is not only automatically performed when the image reading apparatus is activated, but also intentionally performed when the light source unit 70 is attached or detached, when the LED array substrate 37 that is a light source is replaced, or during maintenance. Also good.

[Modification]
In the above embodiment, the case where the present invention is applied to the image reading apparatus has been described. However, the present invention is not limited to this, and an image is output based on image data read by the image reading apparatus. The present invention can be similarly applied to an image forming apparatus further provided with an image output means.

DESCRIPTION OF SYMBOLS 10 Cover part 11 Original separation roll 12 Original conveyance roll 13 Reading roll 14 Discharge roll 16 White reference plate 17 Original tray 18 White reference patch 20 Main part 21 Platen glass 30 Image reading part 31 Light guides 32, 33 Reflection mirror 34 Imaging lens 35 Photoelectric conversion element 36 White LED
37 LED array substrate 41 A / D conversion unit 42 Position correction unit 43 Chromaticity area determination unit 44 Lookup table parameter storage unit 45 Parameter selection unit 46 Color space conversion correction unit 50 Document 60 LED for chromaticity area discrimination
61-64 coordinates 70 light source unit S101-S105 step

Claims (7)

A light source device on which a plurality of light emitting components functioning as a light source and a light emitting component for discrimination having a different chromaticity are mounted, and reading means for irradiating a document image with the light source device to read image data ,
A determination unit that determines a chromaticity range of the plurality of light-emitting components based on image data read by the reading unit when the light-emitting component for lighting is turned on and a reference color region is irradiated with light;
Storage means for storing a plurality of conversion coefficients for correcting the chromaticity of the image data read by the reading means;
A selection means for selecting a conversion coefficient corresponding to a determination result in the determination means from a plurality of conversion coefficients stored in the storage means;
Correction means for correcting the chromaticity of the image data read by the reading means, using the conversion coefficient selected by the selection means;
An image reading apparatus comprising:   The image reading apparatus according to claim 1, wherein the conversion coefficient is a conversion coefficient for converting image data of a certain color system into image data of another color system. A light source device on which a plurality of light emitting components functioning as a light source and a light emitting component for discrimination having a different chromaticity are mounted, and reading means for irradiating a document image with the light source device to read image data Determining means for determining a chromaticity range of the plurality of light emitting components based on image data read by the reading means when the light emitting component for lighting is turned on and light is irradiated on a reference color region; and the reading A storage unit that stores a plurality of conversion coefficients for correcting the chromaticity of the image data read by the unit, and corresponds to a determination result in the determination unit among the plurality of conversion coefficients stored in the storage unit Selection means for selecting a conversion coefficient to be corrected, and correction means for correcting the chromaticity of the image data read by the reading means, using the conversion coefficient selected by the selection means. An image reading device,
Image output means for outputting an image based on image data read by the image reading device;
An image forming apparatus.   A light source device in which a plurality of light emitting components functioning as a light source and a light emitting component for discrimination having different chromaticity are mounted.   The light source device according to claim 4, wherein the light emitting component for determination is mounted on the same line as the plurality of light emitting components functioning as a light source on the light source device. A light source device in which a plurality of light emitting components functioning as a light source and a light emitting component for discrimination having a different chromaticity are mounted;
A light guide member for guiding light from the light source device;
A fixing member that fixes a positional relationship between the light source device and the light guide member;
Light source unit with Lighting a light-emitting component for determination with respect to a light source device in which a plurality of light-emitting components functioning as a light source and a light-emitting component for determination having different chromaticity are mounted;
Determining a chromaticity range of the plurality of light-emitting components based on image data read when the reference color region is irradiated with light from the light-emitting light-emitting component for determination,
Selecting a conversion coefficient corresponding to the determined chromaticity range from a plurality of conversion coefficients;
A program for causing a computer to execute a step of correcting chromaticity of read image data using a selected conversion coefficient.

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