JP2015115934A - Image reader, reading method of the same and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce burden of an installation worker and the like during installation and to eliminate unnecessary power consumption even if an auxiliary illumination device is additionally installed to operate it.SOLUTION: An image reader includes: an imaging section for imaging an imaging object to obtain an image; an illumination section having a plurality of light sources for illuminating the imaging object; a storage section for storing setting information including information on an illumination pattern and an imaging parameter for each size of a medium of a reading object, which can be set as the imaging object; a detection section for detecting the size of the medium of the imaging object, which is set as the imaging object; and a selection section for selecting the setting information corresponding to the size detected by the detection section from the setting information for each size, which is stored in the storage section. The illumination section lights on or off the plurality of light sources in accordance with the illumination pattern corresponding to the setting information selected by the selection section. The image obtained by imaging the medium of the reading object, which is the imaging object, by the imaging section is acquired as a reading image under the imaging parameter corresponding to the setting information.

Description

  The present invention relates to an image reading apparatus such as a stand type image scanner apparatus (stand type image reader apparatus).

  Conventionally, in a financial institution or the like, a stand type image scanner device (hereinafter referred to as “stand scanner”) is used. The stand scanner is a non-contact type image reading apparatus suitable for reading a tax public deposit form (payment of taxes, utility charges, etc.), a medium that cannot be handled by an auto-feeder type image reader apparatus, or the like. In a financial institution, etc., after using the stand scanner to convert the reading target medium into electronic data (image data), character recognition by OCR (Optical Character Recognition) processing or seal verification processing by overlaying imprint images is performed. ing. Here, in order to improve the accuracy of the OCR processing and the seal collation processing, reading is performed at a constant brightness regardless of the illumination environment (hereinafter also referred to as “installation environment”) of the installation location of the stand scanner. It is important to prevent unnecessary information such as shadows and noises from being included in the read image.

  In general, the stand scanner includes, for example, an imaging unit 401, a pedestal 402, a stand 403, and a control unit (not shown), as shown in FIG. It has the structure supported by the stand 403. For this reason, the imaging unit 401 performs imaging in a state of being separated from the reading target medium placed on the pedestal 402, and thus can perform imaging even when the reading target medium is, for example, a thick form. it can.

  In addition, since the stand scanner does not have a light source, the ambient light (such as light from a fluorescent lamp on the ceiling) is reflected by the image sensor of the imaging unit 401 to capture the light reflected from the surface of the medium to be read. I do. Therefore, the brightness of the surface of the read target medium placed on the pedestal 402 may not be uniform due to the influence of ambient light and shadows. Therefore, in consideration of such a case, the stand scanner uses the initial state information (also referred to as “calibration information”) acquired by reference adjustment (also referred to as “calibration”) performed at the time of installation or arbitrary adjustment. Based on sensitivity adjustment (brightness adjustment) based on imaging parameters (exposure time and / or gain amplifier value, etc.) of the imaging unit 401 and image correction that removes shadows, the difference in the read image due to the difference in installation environment Is prevented from occurring. For example, as shown in FIG. 11, an image having the same brightness is read regardless of whether the installation environment is bright or dark. Note that the stand scanner acquires the above-described initial state information as follows, for example. As shown in FIG. 12, the stand scanner first determines appropriate imaging parameters based on an image 501 obtained by the imaging unit 401 imaging a reference medium (also referred to as “calibration medium”). Next, image correction for removing shadows is performed on the image 502 obtained by the imaging unit 401 imaging the reference medium under the imaging parameters, and an image 503 is obtained. Then, information including an appropriate imaging parameter and a correction amount at the time of image correction at this time is acquired as initial state information.

  However, sensitivity adjustment and image correction by such a method are limited. For example, when the installation environment is extremely dark or there is an extremely strong shadow on the pedestal 402, appropriate initial state information cannot be acquired, so sensitivity adjustment and image correction cannot be performed appropriately. There is a fear. Therefore, in such a case, an auxiliary lighting device (such as a stand fluorescent lamp) is additionally installed to compensate for the amount of light and prevent a shadow from being generated on the pedestal 402. The operation in this case is as shown in FIG. 13, for example. In this operation example, first, when the stand scanner is installed (hereinafter simply referred to as “installation”), an installation worker, an operator, or the like (hereinafter referred to as “installation worker”) turns on the auxiliary lighting device (S201). The position and orientation of the auxiliary illumination device are adjusted so that the entire pedestal surface (photographing surface) has uniform brightness (so that it is uniformly illuminated and no shadow is produced) (S202). Thereafter, the initial state information is obtained by the same method as the conventional method, and is stored as a setting file (S203). When the stand scanner is operated (hereinafter simply referred to as “operation”), the auxiliary illumination device is turned on, and an image is read based on the stored setting file (S204).

  In addition, as a stand scanner, for example, a stand type that can automatically determine whether the lighting environment at the installation location is appropriate without requiring a dedicated measuring instrument for measuring illuminance. An image scanner is also known (see Patent Document 1).

JP 2012-231338 A

When the auxiliary lighting device is additionally installed as described above, there are the following problems.
First, since the lighting / extinguishing of the auxiliary lighting device and the position and orientation of the auxiliary lighting device are performed based on the judgment of the installation worker as described above, there is a problem that the burden on the installation worker is heavy. There is. In addition, due to work mistakes such as installation workers, the auxiliary lighting device may be left turned off, or the auxiliary lighting device may not be installed in an appropriate position or orientation. There is also the problem of being.

  In addition, since the illumination by the auxiliary illumination device is uniformly performed on the medium to be read of all sizes, for example, when the size of the medium to be read is small, the range other than the medium to be read is on the base 402. In addition, there is a problem that illumination is performed and unnecessary power consumption is incurred.

  In view of the above circumstances, the present invention can reduce the burden of installation workers and the like and eliminate unnecessary power consumption even when an auxiliary lighting device is additionally installed and operated. An object is to provide an apparatus, a reading method thereof, and a recording medium.

  According to one aspect of the apparatus, the image reading apparatus includes an imaging unit that captures an image of an imaging target and obtains an image, an illumination unit that includes a plurality of light sources for illuminating the imaging target, and the imaging target A storage unit that stores setting information including information on illumination patterns and imaging parameters for each size of a reading target medium that can be an object, and a detection unit that detects the size of the reading target medium that is the imaging target; A selection unit that selects setting information corresponding to the size detected by the detection unit from the setting information for each size stored in the storage unit, and the setting information selected by the selection unit A reading target medium in which the illumination unit turns on or off each of the plurality of light sources according to an illumination pattern corresponding to the image, and the imaging unit is the imaging object under an imaging parameter corresponding to the setting information Acquiring an image reading an image obtained by imaging.

  According to one aspect of the method, there is provided an image reading method for an image reading apparatus, comprising: an imaging unit that captures an image of an imaging target to obtain an image; and an illumination unit that includes a plurality of light sources for illuminating the imaging target. When the image reading apparatus is installed, the plurality of light sources are turned off, and the imaging unit repeatedly captures an image of the calibration medium as the imaging object under different imaging parameters. The first illumination pattern is determined based on the image when the image to be satisfied satisfies the predetermined condition, and the first illumination pattern and the size are determined for each size of the read target medium that can be the imaging object. And determining a third illumination pattern based on the second illumination pattern determined in advance, and turning on or off each of the plurality of light sources according to the third illumination pattern. Under the imaging parameters, the imaging unit repeatedly captures an image of the calibration medium that is the imaging object, and acquires an imaging parameter when an image obtained by the imaging unit satisfies a predetermined condition, and is determined Store the setting information including information on the third illumination pattern and the acquired imaging parameter in the storage unit, and repeat the process of turning off the plurality of light sources during the operation of the image reading apparatus. Detecting the size of the medium to be read as the imaging object, selecting setting information corresponding to the detected size from the setting information for each size stored in the storage unit, and selecting the selection The illumination unit turns on or off each of the plurality of light sources according to an illumination pattern corresponding to the set information, and an imaging parameter corresponding to the set information Acquiring an image reading an image in which the imaging unit is obtained by imaging the read object medium is to the imaged object under process a computer executes.

  According to one aspect of the recording medium, there is provided a processing program for an image reading apparatus including: an imaging unit that captures an image of an imaging target and obtains an image; and an illumination unit that includes a plurality of light sources for illuminating the imaging target. A recorded computer-readable recording medium comprising: a calibration medium in which the plurality of light sources are turned off and the imaging unit is set as the imaging object under different imaging parameters when the image reading apparatus is installed. A first illumination pattern is determined based on the image obtained by repeating the imaging and the image obtained by the imaging unit satisfies a predetermined condition, and the first illumination pattern is determined for each size of the read target medium that can be the imaging target. A third illumination pattern is determined based on the first illumination pattern and a second illumination pattern that is determined in advance according to the size, and is in accordance with the third illumination pattern. Each of the plurality of light sources is turned on or off, and the image obtained by the imaging unit when the imaging unit repeats imaging of the calibration medium set as the imaging target under different imaging parameters satisfies a predetermined condition. When the image reading apparatus is in operation, the imaging parameter when it is satisfied is acquired, and setting information including information regarding the determined third illumination pattern and the acquired imaging parameter is stored in the storage unit. And detecting the size of the medium to be read as the imaging target when the plurality of light sources are turned off, and detecting the size from the setting information for each size stored in the storage unit The setting information corresponding to the selected size is selected, and the illumination unit lights each of the plurality of light sources according to the illumination pattern according to the selected setting information. Is a process for causing the computer to execute a process of turning off the light and acquiring an image obtained by the imaging unit imaging the read target medium as the imaging target object as a read image under an imaging parameter corresponding to the setting information A recording medium on which a program is recorded.

  The disclosed apparatus, method, and medium can reduce the burden during installation of installation workers and the like and eliminate unnecessary power consumption even when the auxiliary lighting device is additionally installed and operated. There is an effect.

1 is a diagram illustrating a configuration example of an image reading apparatus according to an embodiment. It is a figure which shows an example of the several light source which an auxiliary | assistant illumination part has. 4 is a flowchart illustrating an operation example of the image reading apparatus according to the embodiment. It is a 1st figure explaining an example of the determination method of a 1st illumination pattern. It is a 2nd figure explaining an example of the determination method of a 1st illumination pattern. It is a figure explaining an example of the 2nd illumination pattern. It is a figure explaining an example of the determination method of a 3rd illumination pattern. It is a figure which shows an example of a setting file. It is a figure which shows the hardware structural example of a control part. It is a figure which shows the example of an external appearance structure of a stand scanner. It is a figure explaining the example from which the image of the same brightness is obtained irrespective of the brightness of an installation environment. It is a figure explaining the acquisition method of the conventional initial state information. It is a figure which shows an example of the conventional operation | movement.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram illustrating a configuration example of an image reading apparatus according to an embodiment of the present invention. Note that the image reading apparatus according to the present embodiment is, for example, a stand scanner used in a financial institution or the like.

  As illustrated in FIG. 1, the image reading apparatus 100 according to the present embodiment includes an image reader 110, an auxiliary illumination unit 120, and a control unit 130.

  The image reader 110 includes, for example, the imaging unit 401, the pedestal 402, and the stand 403 illustrated in FIG. 10 as external configurations, and includes an image acquisition unit 111 and an imaging parameter adjustment unit 112 as internal configurations. The image acquisition unit 111 includes, for example, a CCD (Charge-Coupled Device) image sensor, a CMOS (Complementary Metal Oxide Semiconductor) image sensor, and the like, and an imaging object (for example, a tax public deposit form) placed on the pedestal 402, Imaging is performed under imaging parameters (such as exposure time and / or gain amplifier value) set by the imaging parameter adjustment unit 112 to acquire image data, and the image data is transmitted to the control unit 130. The imaging parameter adjustment unit 112 sets the corresponding imaging parameter in the image acquisition unit 111 according to the instruction signal transmitted from the control unit 130.

  The auxiliary illumination unit 120 includes a plurality of light sources for illuminating the imaging target medium placed on the pedestal 402, and turns on or turns off each of the plurality of light sources according to an instruction signal transmitted by the control unit 130. Turns off. For example, the auxiliary illumination unit 120 includes nine light sources arranged in a 3 × 3 matrix as shown in FIG.

  The control unit 130 controls the overall operation of the image reading apparatus 100, and includes an image processing unit 131, a setting selection unit 132, a storage unit 133, and an auxiliary illumination adjustment unit 134. The image processing unit 131 performs various types of image processing (including shadow correction processing) on the image data transmitted by the image reader 110. In addition, the image processing unit 131 detects the size of the reading target medium that is the imaging target based on the image data transmitted by the image reader 110, and transmits the detection result to the setting selection unit 132. Do. The setting selection unit 132 relates to a detection result transmitted by the image processing unit 131 from setting files (setting information) for each size of the read target medium that can be an imaging target, stored in the storage unit 133. Select the configuration file that corresponds to the size. The storage unit 133 stores information on an illumination pattern (second illumination pattern described later) for each size of a reading target medium that can be an imaging target, a setting file for each size of the reading target medium that can be an imaging target, and the like. Remember. Here, as will be described in detail later, the illumination pattern for each size is an illumination pattern that is determined in advance according to the size, and is a read target medium of the size in the plurality of light sources of the auxiliary illumination unit 120. Is determined according to the minimum light source required to illuminate the light source. Further, as will be described in detail later, the setting file for each size is stored in the storage unit 133 by an operation when the image reading apparatus 100 is installed (hereinafter simply referred to as “at the time of installation”). 3rd illumination pattern) and imaging parameter information and shadow correction information. The auxiliary illumination adjustment unit 134 transmits an instruction signal for turning on or off each of the plurality of light sources included in the auxiliary illumination unit 120 to the auxiliary illumination unit 120.

  Note that in the image reading apparatus 100 having such a configuration, the image acquisition unit 111 is also an example of an imaging unit that captures an imaging target and obtains an image. The auxiliary illumination unit 120 is also an example of an illumination unit having a plurality of light sources for illuminating the imaging object. The storage unit 133 is also an example of a storage unit that stores setting information including information on illumination patterns and imaging parameters for each size of a reading target medium that can be an imaging target. The image processing unit 131 is also an example of a detection unit that detects the size of a reading target medium that is an imaging target. The setting selection unit 132 is also an example of a selection unit that selects setting information corresponding to the size detected by the detection unit from the setting information for each size stored in the storage unit.

FIG. 3 is a flowchart illustrating an operation example of the image reading apparatus 100 according to the present embodiment.
As shown in FIG. 3, in this operation example, at the time of installation, the control unit 130 performs the following operation at installation (S101 to S107).

  First, under the control of the control unit 130, all of the plurality of light sources of the auxiliary illumination unit 120 are turned off (S101).

  Subsequently, the control unit 130 measures the intensity distribution of the shadow on the pedestal surface (imaging surface) that is the imaged surface by the image acquisition unit 111, and the necessary light source of the auxiliary illumination unit 120 in which the entire pedestal surface has uniform brightness. Processing for estimating the location is performed (S102, S103). More specifically, first, under the control of the control unit 130, the image acquisition unit 111 repeats imaging of a reference medium that is an imaging target under different imaging parameters. The reference medium is, for example, a medium having a single color and the same size as the pedestal surface. Then, the control unit 130 sets the first illumination pattern based on the image when the image related to the image data transmitted from the image reader 110 satisfies a predetermined condition while the image acquisition unit 111 repeats imaging of the reference medium. To decide. Here, the predetermined condition is, for example, a condition that the maximum gradation value of the image (such as the maximum gradation value of the pixels in the image) becomes a predetermined value or a substantially predetermined value. Here, the predetermined value is a value determined in consideration of the gradation range of the representable image. For example, if the gradation range of the representable image is 0 to 255, the predetermined value is 200, for example. If the maximum gradation value does not reach the predetermined value even when shooting with the imaging parameter that can take the highest gradation, within the imaging parameter of the device, the highest gradation can be taken. The first illumination pattern is determined based on the image captured with the imaging parameters. The details of the first illumination pattern determination method will be described later with reference to FIGS.

  Subsequently, the control unit 130 repeats the processes of S104 and S105 for each size of the read target medium that can be an imaging target.

  First, the control unit 130 performs a process for estimating the minimum necessary light source location of the auxiliary illumination unit 120 for the size to be processed (S104). More specifically, the control unit 130 determines the third illumination pattern based on the first illumination pattern and information on the second illumination pattern that is determined in advance according to the size stored in the storage unit 133. Determine the lighting pattern. Details of the second illumination pattern will be described later with reference to FIG. Details of the third illumination pattern determination method will be described later with reference to FIG.

  Subsequently, the control unit 130 performs processing for storing the initial state in the storage unit 133 as a setting file (S105). More specifically, first, under the control of the control unit 130, each of the plurality of light sources of the auxiliary illumination unit 120 is turned on or off according to the third illumination pattern determined in S104. Subsequently, under the control of the control unit 130, the image acquisition unit 111 repeats imaging of the reference medium as the imaging target under different imaging parameters. And the control part 130 acquires an imaging parameter when the image which concerns on the image data transmitted from the image reader 110 in the meantime satisfy | fills predetermined conditions. Here, the predetermined condition is, for example, a condition that the maximum gradation value of the image (such as the maximum gradation value of the pixels in the image) becomes a predetermined value or a substantially predetermined value. Here, the predetermined value is a value determined in consideration of the gradation range of the representable image. For example, if the gradation range of the representable image is 0 to 255, the predetermined value is 200, for example. Subsequently, the control unit 130 generates shadow correction information based on the image when the predetermined condition is satisfied. Subsequently, the control unit 130 stores, as a setting file for the size, a setting file including information on the acquired imaging parameter, generated shadow correction information, and information on the third illumination pattern determined in S104. Stored in the unit 133. Details of the setting file will be described later with reference to FIG.

  Subsequently, it is determined whether or not all sizes of the read target medium that can be the imaging target are processed (S106). If the determination result is No, a new size that is not yet processed is selected. Return to S104 as a target to be processed.

  On the other hand, if the determination result in S106 is Yes, all of the plurality of light sources of the auxiliary illumination unit 120 are turned off under the control of the control unit 130 (S107), and the operation at the time of installation ends. Then, the operation proceeds to the operation at the time of operation of the image reading apparatus 100 (hereinafter simply referred to as “operation”).

  In the operation at the time of operation, for example, the following operation at the time of reading (S108 to S112) is performed in response to a reading instruction from the user.

  First, the control unit 130 performs processing for estimating the medium size in a state where all of the plurality of light sources of the auxiliary illumination unit 120 are turned off (S108). More specifically, the image acquisition unit 111 is set as an imaging target under the control of the control unit 130 in a state where all of the plurality of light sources of the auxiliary illumination unit 120 are turned off by the processing of S107 or S112 described later. The medium to be read on the pedestal 402 is imaged. Then, the control unit 130 detects the size of the medium to be read based on the image related to the image data transmitted from the image reader 110 at that time. This detection is performed based on the luminance distribution of the image, for example.

  Subsequently, the control unit 130 selects a setting file corresponding to the size detected in S108 from the setting files stored in the storage unit 133 for each size of the medium to be read that can be an imaging target. And read (S109). If the size cannot be detected in S108 or if the size is inappropriately detected, a setting file corresponding to the maximum size of the read target medium that can be the imaging target is selected and read.

  Subsequently, under the control of the control unit 130, each of the plurality of light sources of the auxiliary illumination unit 120 is turned on or off according to the illumination pattern related to the information related to the third illumination pattern included in the setting file read in S109. (S110).

  Subsequently, the control unit 130 performs processing for reading the reading target medium on the pedestal 402 (S111). More specifically, under the control of the control unit 130, the image acquisition unit 111 images the reading target medium on the pedestal 402 under the imaging parameters related to the imaging parameter information included in the setting file read in S109. . Then, the control unit 130 acquires an image related to the image data transmitted from the image reader 110 at that time as a read image. If necessary, the read image may be further subjected to shadow correction processing according to the shadow correction information included in the setting file read in S109.

  When the read image is acquired in this way, all of the plurality of light sources of the auxiliary illumination unit 120 are turned off under the control of the control unit 130 (S112), and the operation at the time of reading ends. And it will be in a standby state until the next reading instruction | indication is performed.

  Note that the read image acquired by the reading operation is subsequently subjected to, for example, character recognition by OCR processing or seal collation processing by overlaying seal images.

  4 and 5 are diagrams illustrating an example of the above-described first illumination pattern determination method. In this example, the auxiliary illumination unit 120 will be described as having 9 (= 3 × 3) light sources shown in FIG.

  As shown in FIG. 4, the first illumination pattern is obtained when the image acquisition unit 111 repeatedly captures the reference medium 201 and the image related to the image data transmitted from the image reader 110 satisfies a predetermined condition. It is determined based on the reference medium image 202 that is the image. More specifically, the reference medium image 202 is determined based on the average gradation value of each image area when the reference medium image 202 is divided into nine image areas corresponding to the nine light sources of the auxiliary illumination unit 120.

  In this example, in the reference medium image 202 shown in FIG. 4, the three uppermost image areas are sequentially designated as image areas R1, R2, and R3 from the left, and the three middle image areas are designated as image areas R4 in order from the left. , R5, R6, and the three lowest image areas are image areas R7, R8, R9 in order from the left. In the nine light sources shown in FIG. 2, the top three light sources are sequentially designated as light sources L1, L2, and L3 from the right, and the middle three light sources are designated light sources L4, L5, and L6 in order from the right, and These three light sources are referred to as light sources L7, L8, and L9 in order from the right. The image region Rn corresponds to the light source Ln (where n is an integer from 1 to 9). In this example, the average gradation value of the image region Rn is An (where n is an integer from 1 to 9). Here, the average gradation value of the image area is, for example, an average of gradation values of pixels included in the image area. Further, the maximum one of the nine average gradation values of the image regions R1 to R9 is set as the maximum average gradation value A_MAX. The ratio (A_MAX / An) of the maximum average gradation value A_MAX to the average gradation value An of the image region Rn is Sn (where n is an integer from 1 to 9).

  In this case, in the first illumination pattern, whether the average gradation value An (where n is an integer from 1 to 9) is equal to or greater than a predetermined value (a value corresponding to a required gradation value), Whether the average maximum gradation value A_MAX is equal to or greater than a predetermined value (a value corresponding to a required gradation value), a ratio Sn (where n is an integer from 1 to 9) is a predetermined value (shadow tolerance) It is determined based on the result of determining one or more of whether or not the value corresponding to the limit).

  For example, as in the reference medium image 202a shown in FIG. 5, when the average maximum gradation value A_MAX is not equal to or greater than a predetermined value (“necessary gradation”), the image areas R1 to R9 (all the dotted lines) An illumination pattern for turning on the light sources L1 to L9 (all the light sources) corresponding to the image region is determined as the first illumination pattern. As described above, when a reference medium image having a low gradation is obtained as a whole, it is considered that the illuminance is generally insufficient. Therefore, in the first illumination pattern, all the light sources are turned on to compensate for it. It becomes an illumination pattern to be made.

  Alternatively, when the ratios S1 to S3 of the image areas R1 to R3 indicated by the dotted frame are all equal to or larger than a predetermined value (“shadow allowable limit”) as in the reference medium image 202b shown in FIG. An illumination pattern for lighting only the light sources L1 to L3 corresponding to the image regions R1 to R3 is determined as the first illumination pattern. In this way, when a reference medium image is obtained in which the ratio is partially increased although the gradation is not entirely low, it is considered that there is a partial shadow although the illumination is not entirely insufficient. Therefore, the first illumination pattern is an illumination pattern in which only a part of the corresponding light source is lit to eliminate the shadow.

  FIG. 6 is a diagram illustrating an example of the second illumination pattern described above. In this example, the size of the medium to be read that can be used as an imaging object is described as, for example, A5 size, A4 size defined by ISO216, B6 size, B5 size defined by JIS standard, or license size. To do. Also in this example, the auxiliary illumination unit 120 will be described as having 9 (= 3 × 3) light sources shown in FIG.

  As described above, the second illumination pattern is determined in advance according to the size of the reading target medium, and this illuminates the reading target medium of the size in the plurality of light sources of the auxiliary illumination unit 120. Is determined according to the minimum required light source. More specifically, in the second illumination pattern, for example, the reference medium image obtained by imaging the reference medium by the image acquisition unit 111 is divided into nine image regions corresponding to the nine light sources of the auxiliary illumination unit 120. Among the nine image areas, the image acquisition unit 111 lights only the light source corresponding to the image area partially or wholly overlapped with the read target medium image obtained by imaging the read target medium. It becomes an illumination pattern to be made. In this example as well, as described with reference to FIGS. 4 and 5, the nine image areas of the reference medium image are R1 to R9, and the nine light sources of the auxiliary illumination unit 120 are L1 to L9. The image region Rn corresponds to the light source Ln (where n is an integer from 1 to 9).

  In this case, as shown in FIG. 6, the second illumination pattern for the case where the size of the read target medium is B6 size or A5 size is the read target medium image in the image areas R1 to R9 of the reference medium image. Since the image regions partially or entirely overlap with the image regions R1 to R6 indicated by the dotted line frame 211, the illumination regions turn on only the light sources L1 to L6 corresponding to the image regions R1 to R6.

  Further, the second illumination pattern for the case where the size of the read target medium is the B5 size or the A4 size is an image that partially or entirely overlaps the read target medium image in the image areas R1 to R9 of the reference medium image. Since the areas are the image areas R1 to R9 (all image areas) indicated by the dotted frame 212, the illumination patterns turn on the light sources L1 to L9 (all light sources) corresponding to the image areas R1 to R9.

  Further, in the second illumination pattern for the case where the size of the read target medium is a license size, an image area partially or entirely overlapping with the read target medium image is present in the image areas R1 to R9 of the reference medium image. Since the image areas R1 and R2 are indicated by the dotted frame 213, the illumination pattern turns on only the light sources L1 and L2 corresponding to the image areas R1 and R2.

  In the image reading apparatus 100 according to the present embodiment, as described above, information related to the second illumination pattern for each size of the read target medium that can be an imaging target is stored in the storage unit 133. For example, even when the sizes are different, if the contents of the illumination pattern are the same, the second illumination pattern for the B6 size or A5 size, or the second for the B5 size or A4 size shown in FIG. As in the illumination pattern, one second illumination pattern may be provided for a plurality of different sizes.

FIG. 7 is a diagram for explaining an example of the third illumination pattern determination method described above.
As described above, the third illumination pattern is determined based on the first illumination pattern and the second illumination pattern. For example, the third illumination pattern is a light source that is turned on by the first illumination pattern, and An illumination pattern that turns on only the light source that is also lit by the second illumination pattern is determined as the third illumination pattern.

  As shown in FIG. 7, for example, the first illumination pattern is an illumination pattern that lights only the light sources L1 to L3 shown in FIG. 5, and the second illumination pattern is the B6 size or A5 size shown in FIG. Is an illumination pattern (an illumination pattern in which only the light sources L1 to L6 are turned on), the light sources that are turned on together are the light sources L1 to L3, so that only the light sources L1 to L3 are turned on. An illumination pattern is determined as the third illumination pattern. The light sources L1 to L3 are light sources corresponding to the image regions R1 to R3 indicated by the dotted frame 221.

  Alternatively, for example, the first illumination pattern is an illumination pattern that turns on only the light sources L1 to L3 shown in FIG. 5, and the second illumination pattern is an illumination pattern (light source L1) for the B5 size or A4 size shown in FIG. To L9 (illumination pattern for turning on all light sources), the light sources that are turned on between them are the light sources L1 to L3. Therefore, the illumination pattern that lights only the light sources L1 to L3. Is determined as the third illumination pattern. The light sources L1 to L3 are light sources corresponding to the image regions R1 to R3 indicated by the dotted frame 222.

  Alternatively, for example, the first illumination pattern is an illumination pattern that lights only the light sources L1 to L3 shown in FIG. 5, and the second illumination pattern is an illumination pattern (light sources L1, L2) for the license size shown in FIG. In this case, the light sources that are turned on together are the light sources L1 and L2, and therefore the illumination pattern that lights only the light sources L1 and L2 is the third illumination. It is determined as a pattern. The light sources L1 and L2 are light sources corresponding to the image regions R1 and R2 indicated by the dotted frame 223.

  FIG. 8 is a diagram illustrating an example of a setting file. In this example, the auxiliary illumination unit 120 is assumed to have 9 (= 3 × 3) light sources shown in FIG. 2, and the nine light sources are described as L1 to L9.

  As shown in FIG. 8, each setting file includes information on the corresponding size, camera setting information that is information on imaging parameters, shadow correction information, and auxiliary illumination setting information that is information on the third illumination pattern. including. The camera setting information includes information regarding the exposure time and the gain amplifier value. The shadow correction information includes information related to a shadow correction amount (amplification amount for removing a shadow) for each coordinate with respect to the read image. The auxiliary illumination setting information includes information for turning on (“ON”) or turning off (“OFF”) each of the light sources L1 to L9.

  In the operation illustrated in FIG. 3, as described above, the setting file for each size of the read target medium that can be the imaging target is stored in the storage unit 133. However, for example, the size is different. However, if the contents other than the size are the same, one setting file may be provided for a plurality of different sizes, such as the setting file A or the setting file B shown in FIG. .

  As described above, according to the image reading apparatus 100 according to the present embodiment, it is necessary at least in order to compensate for the lack of illuminance and eliminate the presence of shadows for each size of the medium to be read that can be taken as an imaging target by the operation at the time of installation. An illumination pattern for turning on only a light source is automatically determined. Then, the reading target medium is illuminated by the illumination pattern selected according to the size by the reading operation during operation. Therefore, it is not necessary for an installation worker or the like to finely adjust the position or orientation of the auxiliary lighting unit 120 at the time of installation, and the burden on installation of the installation worker or the like is reduced. In addition, this makes it possible to eliminate work mistakes such as installation workers such as forgetting to turn on the auxiliary illumination unit 120 and errors in determining the installation position and installation direction of the auxiliary illumination unit 120. Furthermore, since only the minimum necessary light source is turned on, unnecessary power consumption can be eliminated.

Note that the image reading apparatus 100 according to the present embodiment can be variously modified.
For example, the control unit 130 may be realized by the hardware configuration illustrated in FIG. In this case, the control unit 130 includes a CPU (Central Processing Unit) 301, a RAM (Random Access Memory) 302, a ROM (Read Only Memory) 303, an HDD (Hard Disk Drive) 304, a communication interface 305, a medium reader 306, an input. Each unit includes an output interface 307 and is connected via a bus 308. The CPU 301 controls the overall operation of the image reading apparatus 100 by reading and executing a program stored in the ROM 303 via the RAM 302. Here, the program stored in the ROM 303 may be stored in the HDD 304. A program executed by the CPU 301 may be stored in the RAM 302 from an external device connected to the network via the communication interface 305 and executed by the CPU 301. The program executed by the CPU 301 may be stored in the RAM 302 from the portable recording medium 309 set in the medium reading device 306 and executed by the CPU 301. Examples of the portable recording medium 309 include various types of recording such as a CD-ROM (Compact Disc Read Only Memory), a flexible disc, an optical disc, a magneto-optical disc, a DVD (Digital Versatile Disc), and a USB (Universal Serial Bus) memory. Media can be used. The information stored in the storage unit 133 is stored in the HDD 304, for example. The image reader 110 and the auxiliary illumination unit 120 are connected to the input / output interface 307. A display device 310 and an input device 311 such as a keyboard and a mouse are further connected to the input / output interface 307. The auxiliary illumination unit 120 includes, for example, an input / output interface 321 to which a plurality of light sources L are connected, and the input / output interface is connected to the control unit 130.

  For example, the control unit 130 may include a module such as an FPGA (Field Programmable Gate Array) or a DSP (Digital Signal Processor). In this case, the control unit 130 includes a nonvolatile memory (for example, an EEPROM (Electrically Erasable and Programmable Read Only Memory), a flash memory, a flash memory type memory card, etc.), and module firmware is stored therein. Here, the firmware stored in the non-volatile memory may be written by communication with an external device.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various improvements and modifications can be made without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 100 Image reader 110 Image reader 111 Image acquisition part 112 Imaging parameter adjustment part 120 Auxiliary illumination part 130 Control part 131 Image processing part 132 Setting selection part 133 Storage part 134 Auxiliary illumination adjustment part 201 Reference medium 202 Reference medium image 211,212, 213 Dotted line frame 221, 222, 223 Dotted line frame 301 CPU
302 RAM
303 ROM
304 HDD
305 Communication interface 306 Medium reader 307 Input / output interface 308 Bus 309 Portable recording medium 310 Display device 311 Input device 321 Input / output interface 401 Imaging unit 402 Base 403 Stand 501, 502, 503 Image

Claims (11)

An imaging unit that captures an imaging object and obtains an image;
An illumination unit having a plurality of light sources for illuminating the imaging object;
A storage unit that stores setting information including information about illumination patterns and imaging parameters for each size of a reading target medium that can be the imaging target;
A detection unit that detects a size of a reading target medium that is the imaging target;
A selection unit that selects setting information corresponding to the size detected by the detection unit from the setting information for each size stored in the storage unit;
With
The illumination unit turns on or off each of the plurality of light sources according to an illumination pattern corresponding to the setting information selected by the selection unit, and the imaging unit captures the imaging object under an imaging parameter corresponding to the setting information. An image obtained by imaging the read target medium is acquired as a read image;
An image reading apparatus. The illumination pattern is based on the image obtained when the image obtained by the imaging unit capturing the calibration medium that is the imaging object when the plurality of light sources are turned off satisfies a predetermined condition. A third lighting pattern determined based on the first lighting pattern determined in accordance with the second lighting pattern determined in advance according to the size,
The imaging parameter is obtained by the imaging unit imaging the calibration medium that is the imaging object when the illumination unit turns on or off each of the plurality of light sources according to the third illumination pattern. It is an imaging parameter when the obtained image satisfies a predetermined condition,
The image reading apparatus according to claim 1. The predetermined condition is a condition that the maximum gradation value of the image becomes a predetermined value.
The image reading apparatus according to claim 2. The first illumination pattern is determined based on an average gradation value of each image area when an image when the predetermined condition is satisfied is divided into a plurality of image areas corresponding to the plurality of light sources. ,
The image reading apparatus according to claim 2, wherein the image reading apparatus is an image reading apparatus. In the first illumination pattern, whether the average gradation value of the image area is a predetermined value or more, whether the gradation value of the image area having the maximum average gradation value is a predetermined value or more, It is determined based on the result of determining one or more of whether or not the ratio of the gradation value of the image area where the average gradation value is the maximum to the average gradation value of the area is a predetermined value or more.
The image reading apparatus according to claim 4. The second illumination pattern is determined according to a minimum light source required to illuminate a read target medium of the size in the plurality of light sources.
The image reading apparatus according to claim 2, wherein the image reading apparatus is an image reading apparatus. The detection unit is configured to determine a size of the reading target medium based on a luminance distribution of an image obtained by the imaging unit imaging the reading target medium when the plurality of light sources are turned off. Detect
The image reading apparatus according to claim 1, wherein the image reading apparatus is an image reading apparatus. When the size cannot be detected by the detection unit, or when the size detection by the detection unit is inappropriate, the selection unit stores the setting information for each size stored in the storage unit. Select setting information corresponding to the maximum size from
The image reading apparatus according to claim 1, wherein the image reading apparatus is an image reading apparatus. The imaging parameter is an exposure time or a gain amplifier value.
The image reading apparatus according to claim 1, wherein the image reading apparatus is an image reading apparatus. An image reading method for an image reading apparatus, comprising: an imaging unit that captures an image of an imaging target to obtain an image; and an illumination unit that includes a plurality of light sources for illuminating the imaging target.
At the time of installing the image reading device,
Turning off the plurality of light sources;
The first illumination based on the image when the image obtained by the imaging unit satisfies a predetermined condition by repeating imaging of the calibration medium that is the imaging object by the imaging unit under different imaging parameters. Determine the pattern,
For each size of the read target medium that can be the imaging object,
Determining a third illumination pattern based on the first illumination pattern and a second illumination pattern that is predetermined according to the size;
Turning on or off each of the light sources according to the third illumination pattern;
Under the different imaging parameters, the imaging unit repeats imaging of the calibration medium that is the imaging object, and acquires imaging parameters when an image obtained by the imaging unit satisfies a predetermined condition,
Storing setting information including information on the determined third illumination pattern and the acquired imaging parameter in a storage unit;
Repeat the process
During operation of the image reading apparatus,
When the plurality of light sources are turned off, the size of the read target medium that is the imaging target is detected,
From the setting information for each size stored in the storage unit, select setting information corresponding to the detected size,
The illumination unit turns on or off each of the plurality of light sources according to an illumination pattern corresponding to the selected setting information, and the imaging unit is set as the imaging target under an imaging parameter corresponding to the setting information. Obtaining an image obtained by imaging the read target medium as a read image;
An image reading method, wherein a computer executes the process. A computer-readable recording medium recording a processing program of an image reading apparatus comprising: an imaging unit that captures an image of an imaging target to obtain an image; and an illumination unit that includes a plurality of light sources for illuminating the imaging target There,
At the time of installing the image reading device,
Turning off the plurality of light sources;
The first illumination based on the image when the image obtained by the imaging unit satisfies a predetermined condition by repeating imaging of the calibration medium that is the imaging object by the imaging unit under different imaging parameters. Determine the pattern,
For each size of the read target medium that can be the imaging object,
Determining a third illumination pattern based on the first illumination pattern and a second illumination pattern that is predetermined according to the size;
Turning on or off each of the light sources according to the third illumination pattern;
Under the different imaging parameters, the imaging unit repeats imaging of the calibration medium that is the imaging object, and acquires imaging parameters when an image obtained by the imaging unit satisfies a predetermined condition,
Storing setting information including information on the determined third illumination pattern and the acquired imaging parameter in a storage unit;
Repeat the process
During operation of the image reading apparatus,
When the plurality of light sources are turned off, the size of the read target medium that is the imaging target is detected,
From the setting information for each size stored in the storage unit, select setting information corresponding to the detected size,
The illumination unit turns on or off each of the plurality of light sources according to an illumination pattern corresponding to the selected setting information, and the imaging unit is set as the imaging target under an imaging parameter corresponding to the setting information. Obtaining an image obtained by imaging the read target medium as a read image;
A computer-readable recording medium on which a processing program for causing a computer to execute processing is recorded.