JP6823739B2 - Paper leaf discrimination device, white standard data adjustment method, and program - Google Patents

Description

The present invention relates to a paper leaf discriminator, a method for adjusting white reference data, and a program.

Conventionally, there has been known a paper leaf discrimination device that receives a paper leaf inserted from an insertion slot into a transport path and performs a discrimination process for authenticity, denomination, etc. of the paper leaf. In the above-mentioned paper leaf discrimination device, the paper leaf transported along the transport path is photographed by the image sensor, and image data indicating the paper leaf is generated. The above image data is used for discriminating the authenticity of paper sheets and the like.

For example, Patent Document 1 includes an image sensor including a light emitting means for irradiating one surface of a paper leaf in a transport path with detection light and a light receiving means for incident detection light transmitted to the other surface side of the paper leaf. The paper leaf discrimination device to be used is disclosed. In the above-mentioned paper leaf discrimination apparatus, a technique for shading correction of an image generated by an image sensor may be adopted.

JP-A-2009-295125

The white reference data used for shading correction is generated by a predetermined method. However, depending on the method of generating white reference data (for example, the shape of the white reference member), white for correcting the image data of pixels located in a predetermined specific region (for example, near the side wall of the transport path). It may be difficult to properly generate reference data. In consideration of the above circumstances, it is an object of the present invention to make it possible to adjust the white reference data of the pixels located in the above-mentioned specific region.

In order to solve the above problems, a transport means for moving the paper leaf along the transport path, a light emitting means for irradiating one surface of the moving paper leaf with detection light, and a facing surface with the other surface of the moving paper leaf. In addition to receiving the detection light that has passed through the paper leaf, it corresponds to the light receiving means that are arranged along the width direction orthogonal to the moving direction of the paper sheet and the detection light that is incident on the light receiving means. An image data generation means for generating gradation image data, and a white reference data storage means for storing white reference data obtained by irradiating a white reference member used for shading correction of image data with detection light. Image data of the light receiving means, provided that the movement restricting means located at the widthwise end of the transport path and forming the side wall of the transport path and the widthwise position of the light receiving means are within a predetermined specific region. The white reference data for shading correction is provided with an adjusting means for adjusting to a predetermined value.

According to the present invention, the image of a paper leaf is appropriately shade-corrected.

It is external perspective view and sectional view of the banknote acceptor according to 1st Embodiment. It is an exploded perspective view and the enlarged sectional view of the banknote acceptor according to 1st Embodiment. It is a figure for demonstrating the white reference member which concerns on 1st Embodiment. It is a functional block diagram of the banknote acceptor according to 1st Embodiment. It is a figure for demonstrating the pre-adjustment white reference data which concerns on 1st Embodiment. It is a figure for demonstrating the adjustment method of the white reference data which concerns on 1st Embodiment. It is a flowchart of the pre-shipment adjustment process which concerns on 1st Embodiment. It is a figure for demonstrating the adjustment method of the white reference data which concerns on 2nd Embodiment. It is a figure for demonstrating the white reference data which concerns on 3rd Embodiment.

<First Embodiment>
FIG. 1A is an external perspective view of the banknote acceptor H according to the first embodiment. Further, FIG. 1B is a cross-sectional view taken along the line AA in FIG. 1A. The above-mentioned bill discrimination device H includes a control device including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a flash memory, and the like.

As shown in FIG. 1A, the banknote acceptor H is configured to include the lower unit 1 and the upper unit 2, and is formed in a transport path 4 formed between the upper surface of the lower unit 1 and the lower surface of the upper unit 2. On the other hand, a paper sheet (for example, a banknote) is inserted from the insertion port 3a. The bill inserted into the insertion slot 3a moves in the transport path 4 in the direction of movement indicated by the arrow in FIG. 1 (b).

As shown in FIG. 1B, the banknote acceptor H is provided with a transfer device 5. The transport device 5 includes a plurality of lower transport members 5a composed of a transport drum (roller), a transport belt, etc. arranged on the lower side of the transport path 4, and each lower transport member 5a arranged on the upper side of the transport path 4. It is configured to include an upper transport member 5b composed of a transport drum or the like arranged so as to face each other. The lower transport member 5a according to this example is a transport drum, a transport belt, or the like that is rotationally driven by a motor while being in contact with the lower surface of a bill on its outer peripheral surface. The upper transport member 5b is brought around to the lower transport member 5a via the bill while being in contact with the upper surface of the bill on its outer peripheral surface. The bill inserted into the insertion slot 3a is arranged between the lower transport member 5a and the upper transport member 5b and is niped on both sides, and moves at a constant speed in the transport path 4 as the lower transport member 5a rotates. The transport device 5 for transporting banknotes is not limited to the above example.

As shown in FIG. 1B, the banknote acceptor H includes sensors 6 (6a, 6b, 6c). The control device of the bill identification device H discriminates the authenticity of the bill inserted into the insertion slot 3a according to the information acquired from the sensor 6. Specifically, the sensor 6 includes two image sensors 6 (6a, 6b) and one magnetic sensor 6c. However, the banknotes may be identified by a sensor other than the above sensors.

The first image sensor 6a is a CIS (Contact Image Sensor). The second image sensor 6b is a CIS like the first image sensor 6a. Each of the above image sensors has a light emitting unit (for example, a light emitting element Ga described later) that irradiates a bill in the transport path 4 with detection light, and a light receiving unit (for example, a pixel Gb described later) on which the detection light is incident. Including. Further, the light emitting unit of the image sensor includes two types of light sources, a reflection light source and a transmission light source. Each light source irradiates a plurality of types of detection light having different wavelengths. The "detection light" in the present invention may include invisible light (infrared rays, etc.) in addition to visible light (wavelength = 360 to 760 nm).

For example, the detection light emitted from the reflected light source of the first image sensor 6a is reflected on one side of the bill in the transport path 4 and is incident on the light receiving portion of the first image sensor 6a. Further, the detection light emitted from the reflected light source of the second image sensor 6b is reflected by the other surface of the banknote in the transport path 4 and is incident on the light receiving portion of the second image sensor 6b.

The detection light emitted from the transmitted light source of the first image sensor 6a is transmitted from one side to the other side of the bill in the transport path 4 and is incident on the light receiving portion of the second image sensor 6b. Further, the detection light emitted from the transmitted light source of the second image sensor 6b is transmitted from the other side to the one side of the bill in the transport path 4 and is incident on the light receiving portion of the first image sensor 6a.

The light receiving portion of the image sensor (6a, 6b) is composed of a plurality of pixels. Further, a detection signal corresponding to the detection light (transmitted light, reflected light) incident on the above pixels is input to the above-mentioned control device. The CPU of the control device executes a program stored in the ROM to generate image data indicating a banknote based on the detection signal.

Black correction processing for removing the dark current component is executed from the image data. Further, as will be described in detail later, shading correction is executed on the image data after the black correction processing is executed. Shading correction is a method of reducing uneven brightness contained in image data. For example, the gradation of each pixel of the corresponding image data is divided by the gradation of each pixel of the white reference data to obtain the image data. This is a method of correcting the gradation of each pixel. The white reference data used for shading correction is generated, for example, in the process of manufacturing the banknote acceptor H, and is stored in the flash memory of the control device.

The magnetic sensor 6c detects iron contained in the ink on the printing surface of the banknote. The CPU discriminates banknotes based on the detection signal from the sensor 6 described above. For example, when it is determined that the banknote is not a legitimate banknote, the banknote is ejected from the insertion port 3a by the transport device 5. On the other hand, if it is determined that the banknote is a legitimate banknote, the banknote moves to the intake port 3b. Although detailed description will be omitted, the banknote acceptor H is attached to, for example, the paper sheet processing device described in JP-A-2009-295125. The banknotes that have moved to the intake port 3b of the banknote acceptor H are then stored in the storage unit of the paper sheet processing device.

FIG. 2A is an exploded perspective view of the banknote acceptor H. 2 (b) is a cross-sectional view taken along the line BB in FIG. 1 (a) described above. As shown in FIG. 2A, in addition to the above-mentioned lower unit 1, upper unit 2, first image sensor 6a and second image sensor 6b, the banknote acceptor H includes a lower cover 7, an upper tray 8, and white for reflection. Includes reference piece 9 (9a, 9b). Note that, in FIG. 2B, among the configurations of the banknote acceptor H, other than the first image sensor 6a, the second image sensor 6b, the lower cover 7, the upper tray 8, and the white reference piece 9 (9a, 9b) for reflection. Is omitted.

As shown in FIG. 2A, the upper tray 8 is formed in a substantially box shape having a bottomed recess 8a on the upper surface, and as shown in FIG. 2B, the inside of the recess 8a of the upper tray 8 is formed. The first image sensor 6a is housed in. Further, as shown in FIG. 2B, the lower surface 8b of the upper tray 8 forms the upper surface (ceiling surface) of the transport path 4. The upper tray 8 is made of a light-transmitting material, for example, a transparent resin.

FIG. 2B shows a plurality of light emitting elements Ga that are transmission light sources of the first image sensor 6a. Note that FIG. 2B shows an excerpt of a part of all the light emitting elements Ga. A plurality of the above light emitting elements Ga are provided along the X-axis direction (width direction) orthogonal to the Y-axis direction when the direction in which the bills in the transport path 4 move is the Y-axis direction (conveyance direction). Arranged so as to extend. In this embodiment, 720 light emitting elements Ga are arranged in the X-axis direction.

As shown in FIG. 2B, the first image sensor 6a is housed in the recess 8a of the upper tray 8 so that the light emitting element Ga is located on the lower surface 8b side described above. As described above, the upper tray 8 is light transmissive. Therefore, the detection light emitted from the light emitting element Ga can pass through the upper tray 8 and enter the transport path 4.

As shown in FIG. 2B, the second image sensor 6b of the present embodiment includes a plurality of pixels Gb on which the detection light emitted from the first image sensor 6a is incident. In FIG. 2B, a part of all the pixels Gb is excerpted and shown. The second image sensor 6b is provided with the same number (720 pixels) of pixels Gb as the light emitting elements Ga of the first image sensor 6a. Further, the pixels Gb are arranged in the X-axis direction in the same manner as the light emitting element Ga, and one light emitting element Ga and one pixel Gb face each other so that the optical axes L (see FIG. 2B) coincide with each other. To do.

As shown in FIG. 2A, the lower cover 7 has a right side wall surface 7a, a left side wall surface 7b, a recess 7c formed by notching the transport direction side edge of the lower cover, and a recess 7c penetrating in the vertical direction. An upper surface 7d is provided at a location avoiding the location 7c. As shown in FIG. 2B, the lower cover 7 is provided so as to cover the upper surface (pixel Gb side) of the second image sensor 6b. Further, the upper surface 7d of the lower cover 7 constitutes the bottom surface of the transport path 4. The height (distance h shown in FIG. 2B) from the bottom surface (lower cover 7) of the transport path 4 to the ceiling surface (upper tray 8) in the present embodiment is about 2 mm.

When the lower cover 7 is installed on the lower unit 1, the lower transport member 5a such as the transport belt of the transport device 5 projects to the transport path 4 side via the recess 7c. The banknotes in the transport path 4 move in the transport direction as the transport belt rotates.

The lower cover 7 is formed of a light-transmitting material such as a transparent resin, similarly to the upper tray 8 described above. Therefore, the detection light emitted from the light emitting element Ga of the first image sensor 6a and transmitted through the banknote of the transport path 4 can pass through the lower cover 7 (upper surface 7d) and enter the pixels Gb of the second image sensor 6b. Is.

As shown in FIG. 2B, the right side wall surface 7a and the left side wall surface 7b of the lower cover 7 form a side wall of the transport path 4. Specifically, the right side wall surface 7a forms a side wall on the right side when viewed from a bill moving in the transport path 4. Further, the left side wall surface 7b forms a side wall on the left side when viewed from the banknotes moving in the transport path 4. In the present embodiment, for the sake of explanation, the region from the right side wall surface 7a to the left side wall surface 7b in the region on the X axis (main scanning axis) is referred to as “region R”. The above area R is an area in which an image for discriminating banknotes is taken.

In the present embodiment, the length of the region R (distance from the right side wall surface 7a to the left side wall surface 7b) is about 4 mm longer than the width of the bill moving in the transport path 4 in the X-axis direction. In the above configuration, the width of the transport path 4 is shorter than, for example, a configuration in which the length of the region R is 4 mm or more longer than the width of the bill. Therefore, according to the present embodiment, there is an advantage that the banknote acceptor H can be easily miniaturized.

As described above, the banknote acceptor H of the present embodiment can correct the shading of the image. Specifically, the banknote acceptor H is capable of both shading correction of the image obtained by the reflection light source and shading correction of the image obtained by the transmission light source.

The banknote acceptor H generates white reference data used for shading correction of the image obtained by the reflection light source by using the reflection light source and the light receiving portion outside the above-mentioned region R. On the other hand, the white reference data used for shading correction of the image obtained by the transmission light source (light emitting element Ga) is generated by using the transmission light source and the light receiving unit (pixel Gb) inside the above-mentioned region R.

The banknote acceptor H includes reflection white reference pieces (9a, 9b) for generating white reference data used for shading correction of an image obtained by a reflection light source. As shown in FIG. 2A, the above white reference piece 9 for reflection is provided with two white reflectors T. As shown in FIG. 2B, the white reference piece 9 for reflection is provided so that the reflector T is located in the region r outside the region R. As shown in FIG. 2B, the tip of each reflector T comes into contact with the lower cover 7. In the present embodiment, the pixels Gb are arranged in the entire area R and the area r.

One of the two reflectors T is irradiated with the light emitted from the reflection light source located in the region r of the reflection light sources of the first image sensor 6a. Further, the light emitted from the above-mentioned reflective light source and reflected by the reflector T is incident on the light receiving element (pixel) for the reflected light of the first image sensor 6a. Similarly, the other reflector T of the two reflectors T is irradiated with the light emitted from the reflection light source located in the region r of the reflection light sources of the second image sensor 6b. Further, the light emitted from the above-mentioned reflective light source and reflected by the reflector T is incident on the light receiving element (pixel) for the reflected light of the second image sensor 6b. The CPU of the control device generates white reference data for correcting the image obtained by the reflecting light source according to the gradation of the reflected light from the reflecting plate T incident on the light receiving element.

As described above, the white reference data of the image obtained by the reflection light source is generated by using the reflection white reference piece 9 (reflector T). On the other hand, the white reference data of the image obtained by the transmission light source (light emitting element Ga) is generated by using the white reference member 10 (see FIG. 3) described later. The timing for generating the white reference data of the image obtained by the reflective light source can be appropriately set. For example, the above white reference data may be generated immediately after the bill is inserted into the insertion slot 3a (before the bill is detected by the image sensor).

FIG. 3A is a perspective view of the white reference member 10 described above. In the present embodiment, white reference data is generated using the white reference member 10 in the manufacturing process of the banknote acceptor H. However, the white reference data may be generated at another opportunity. The white reference member 10 is arranged on the transport path 4 (upper surface 7d of the lower cover 7) when generating white reference data (see FIG. 3B described later). Further, the white reference member 10 is removed by the operator after the white reference data is generated. That is, when the banknote acceptor H is shipped as a finished product, the white reference member 10 is not arranged in the transport path 4.

As shown in FIG. 3A, the white reference member 10 includes a white reference sheet 10a and a rectangular annular guard member 10b that holds the outer peripheral edge of the white reference sheet 10a. When the white reference sheet 10a is irradiated with the detection light of the light emitting element Ga, the white reference sheet 10a transmits the same light (type, intensity) as the white portion of the banknote. The white reference sheet 10a described above is formed, for example, with substantially the same thickness as a banknote.

The guard member 10b is a substantially plate-shaped annular member (frame body) having a substantially rectangular outer edge, and is provided with a penetrating opening K as shown in FIG. 3A. The white reference sheet 10a is attached (attached) to the guard member 10b so as to close the opening K. The guard member 10b is made of a material having higher strength and a higher specific gravity (heavy) than the white reference sheet 10a. For example, the guard member 10b is formed of an alloy such as stainless steel.

According to the white reference member 10 provided with the guard member 10b, for example, when the white reference member 10 is arranged in the transport path 4, the white reference sheet 10a is compared with the white reference member 10 composed of only the white reference sheet 10a. There is an advantage that the inconvenience of bending is suppressed. Further, there is an advantage that the inconvenience that the white reference member 10 (white reference sheet 10a) is displaced due to the influence of wind or the like is suppressed.

FIG. 3B is a diagram for explaining the white reference member 10 mounted on the transport path 4. When generating the white reference data, the worker temporarily arranges the white reference member 10 in the transport path 4. Specifically, the white reference member 10 is arranged between the first image sensor 6a and the second image sensor 6b at a position where the detection light emitted by the light emitting element Ga of the first image sensor 6a is irradiated. To.

As shown in FIG. 3B, the length of the long side of the white reference member 10 is close to (substantially equal to) the length of the region R. In the above case, the short side of the white reference member 10 (guard member 10b) is located (substantially abutted) in the vicinity of the side walls (7a, 7b) of the transport path 4. The configuration of the white reference member 10 is not limited to the above example.

When generating the white reference data, the detection light is emitted from the light emitting element Ga in a state where the white reference member 10 is placed in the region R of the transport path 4. In the above case, among the detection lights from the light emitting element Ga, the detection light irradiated to the white reference sheet 10a of the white reference member 10 passes through the white reference sheet 10a and is incident on the pixel Gb. Appropriate white reference data is generated from the detection light incident on the above pixels Gb.

On the other hand, among the white reference members 10, the guard member 10b has a lower light transmittance than the white portion (white reference sheet 10a) of the banknote. For example, when the guard member 10b is made of metal, the detection light is not transmitted. Therefore, when the detection light is irradiated from the light emitting element Ga of the first image sensor 6a with the white reference member 10 installed in the region R, the detection light emitted to the guard member 10b (both ends 10b in the longitudinal direction) is irradiated. Is not transmitted to the second image sensor 6b side, so that the light is not received by the pixel Gb. In the above case, the white reference data for shading correction of the image data generated by the pixel Gb is not properly generated (see FIG. 5B described later).

As understood from the above description, when the white reference data is generated using the white reference member 10 of the present embodiment, the image of the pixel Gb facing both ends 10b in the longitudinal direction of the guard member 10b is corrected. White reference data is not generated properly. That is, the white reference data of the pixel Gb located near the side wall of the transport path 4 is not properly generated. If the white reference data of the pixel Gb located near the side wall of the transport path 4 is not appropriately generated, for example, as shown in FIG. 3C, a problem occurs when the bill B moves near the side wall of the transport path 4. ..

For example, in an ATM (Automatic Teller Machine) device or the like, a technique of injecting stolen ink onto a banknote when it is illegally taken out (stolen) has been adopted (for example, Japanese Patent Application Laid-Open No. 2000). See −322625). From the above circumstances, the bill identification device H preferably has a configuration capable of determining whether or not the stolen ink is attached to the inserted bill. However, the stolen ink often adheres to a portion near the outer edge of the bill in the width direction. Therefore, if the shading correction of the image taken in the vicinity of the side wall of the transport path 4 is not properly performed, it may not be possible to accurately determine whether or not the stolen ink is attached to the banknote.

In consideration of the above circumstances, the banknote acceptor H of the present embodiment has a configuration in which the image near the side wall of the transport path 4 is appropriately shaded and corrected (white reference data generation unit 107 and the like shown in FIG. 4 described later). Equipped. The above-mentioned banknote acceptor H has an advantage that the stolen ink adhering to the vicinity of the outer edge of the banknote can be appropriately detected while the width of the transport path 4 is relatively short.

Specifically, the banknote acceptor H of the present embodiment adjusts the white reference data for correcting the image of the pixel Gb facing the guard member 10b after generating the white reference data using the white reference member 10. Adopted a possible configuration. According to the above configuration, even when the bill B moves near the side wall of the transport path 4, the image of the pixel Gb near the side wall of the transport path 4 is appropriately shaded and corrected, so that the image is clear. The bill B can be identified.

As another method for appropriately generating white reference data of pixels Gb near the side wall of the transport path 4, a region where both ends 10b of the guard member 10b of the white reference member 10 in the longitudinal direction can be placed is set in the region R. A method is conceivable in which the entire region R is provided on the outside (outside of the side wall) so as to face the white reference sheet 10a. However, with the above method, there may be a disadvantage that the banknote acceptor H is difficult to miniaturize. In the present embodiment, the above inconvenience is suppressed.

FIG. 4 is a functional block diagram of the banknote acceptor 100 (H) according to the first embodiment. Various functions are realized by executing the program by the CPU of the banknote acceptor 100. However, in the manufacturing process of the banknote acceptor 100, the banknote acceptor 100 is communicably connected to an external computer, and the external computer has a part of each function shown in FIG. 4 (for example, the white reference data generation unit 107 described later). May be realized. In the above case, the combination of the banknote acceptor 100 and the external computer can correspond to the "paper sheet acceptor" of the present invention.

As shown in FIG. 4, the banknote acceptor 100 includes a transport control unit 101, a sensor unit 102, a sensor control unit 103, an image data generation unit 104, a white reference data storage unit 105, a correction unit 106, and a white reference data generation unit 107. Equipped. The transport control unit 101 controls the above-mentioned transport device 5. For example, when a bill is inserted into the insertion slot 3a, the transport control unit 101 outputs a drive signal for rotating the transport unit 5a (convey belt or the like) of the transport device 5 so that the bill moves in the transport direction. ..

The sensor unit 102 includes the first image sensor 6a and the second image sensor 6b described above. Further, the sensor control unit 103 controls lighting of the light emitting element Ga of the first image sensor 6a. For example, the sensor control unit 103 lights the light emitting element Ga during the period during which the banknote passes through the above-mentioned area R (hereinafter referred to as “shooting period”). Further, the sensor control unit 103 inputs a signal indicating the gradation of the detection light (detection light transmitted through the banknote) incident on each pixel Gb at each time point in the shooting period to the image data generation unit 104 described later.

The sensor control unit 103 of the present embodiment lights the light emitting element Ga during the period for generating white reference data (hereinafter referred to as “generation period”) in the manufacturing process of the banknote acceptor H. Further, the sensor control unit 103 outputs a signal indicating the gradation of the detection light (detection light transmitted through the white reference sheet 10a) incident on each pixel Gb at each time point in the above generation period to a white reference data generation unit described later. Input to 107.

The image data generation unit 104 generates image data showing an image of a banknote inserted into the insertion slot 3a. Specifically, at each time point in the photographing period in which the bill passes through the above-mentioned region R, a signal indicating the gradation of the detection light (detection light transmitted through the bill) incident on each pixel Gb is sent to the image data generation unit 104. Entered. The image data generation unit 104 generates image data indicating the banknote from the above signals.

The white reference data storage unit 105 stores the white reference data used for shading correction of the image data generated by the image data generation unit 104. The above white reference data is generated by the white reference data generation unit 107 described later.

The correction unit 106 uses the above-mentioned white reference data to perform shading correction of the image data generated by the image data generation unit 104. In the banknote discriminating device 100, black correction processing of image data is executed prior to shading correction. Specifically, the banknote acceptor 100 stores the dark current component acquired from the pixel Gb during the period when the light emitting element Ga of the image sensor (6a, 6b) is turned off. Further, when the image data is generated, the banknote acceptor 100 subtracts the above-mentioned dark current component from the image data.

The white reference data generation unit 107 includes an adjustment position determination unit 108 and an adjustment unit 109, and generates white reference data stored in the white reference data storage unit 105. As described above, the white reference data generation unit 107 receives the detection light (detection light transmitted through the white reference sheet 10a) incident on each pixel Gb during the generation period in which the white reference data is generated in the manufacturing process of the banknote acceptor 100. ) Is input from the sensor unit 102 described above. The white reference data generation unit 107 generates pre-adjustment white reference data (see FIG. 5B described later) from the above signals.

The pre-adjustment white reference data is data that can specify the gradation of the detected light incident during the generation period for each pixel Gb. The adjustment position determination unit 108 of the white reference data generation unit 107 determines the pixel Gb for adjusting the pre-adjustment white reference data from the pixels Gb arranged in the scanning axis direction. As will be described in detail later, the adjustment position determining unit 108 can determine the pixel Gb facing the guard member 10b of the white reference member 10.

The adjustment unit 109 of the white reference data generation unit 107 adjusts the pre-adjustment white reference data of the pixel Gb determined by the adjustment position determination unit 108 to a predetermined value (“average gradation Iave” described later). The white reference data generation unit 107 stores the white reference data adjusted by the adjustment unit 109 in the white reference data storage unit 105.

5 (a) and 5 (b) are diagrams for explaining the pre-adjustment white reference data. 5 (a) is a sectional view taken along line BB shown in FIG. 1 (a), similar to FIG. 2 (b) described above. However, in FIG. 5A, the first image sensor 6a, the second image sensor 6b, the lower cover 7, and the upper tray 8 are excerpted from each configuration of the banknote acceptor 100. Further, FIG. 5A shows an optical path of the detection light emitted from the light emitting element Ga by a broken line arrow.

In the specific example of FIG. 5A, it is assumed that the white reference member 10 (white reference sheet 10a, guard member 10b) is arranged in the region R of the transport path 4. As described above, when the white reference member 10 is placed on the transport path 4, both ends 10b of the guard member 10b of the white reference member 10 in the longitudinal direction are located near the side walls (7a, 7b) of the transport path 4. ..

As shown in FIG. 5A, of the detection light emitted from the first image sensor 6a (light emitting element Ga), the detection light emitted to both ends 10b in the longitudinal direction of the white reference sheet 10a is the white reference sheet 10a. Is transmitted to the second image sensor 6b (pixel Gb). On the other hand, of the detection light emitted from the first image sensor 6a, the detection light emitted to both ends 10b in the longitudinal direction of the guard member 10b is not transmitted to the second image sensor 6b side. Therefore, the detection light emitted to both ends 10b in the longitudinal direction of the guard member 10b does not reach the second image sensor 6b.

FIG. 5B is a diagram for explaining the pre-adjustment white reference data. FIG. 5B shows the gradation I (brightness) of the detection light (transmitted light) incident on the second image sensor 6b at each position on the X-axis of the area R (the area between the side walls of the transport path 4). ) Is shown. In the present embodiment, for the sake of explanation, the position on the X-axis of the right side wall surface 7a (right end of the region R) of the transport path 4 is described as "position Pea". Similarly, the position on the X-axis of the left side wall surface 7b (left end of the region R) of the transport path 4 is described as “position Peb”.

Further, the region on the X-axis where both ends 10b in the longitudinal direction of the guard member 10b located near the right side wall surface 7a and the second image sensor 6b face each other is described as "region Rx". Similarly, the region on the X-axis where the guard member 10b located in the vicinity of the left wall surface 7b and the second image sensor 6b face each other is referred to as "region Ry".

In the specific example of FIG. 5B, it is assumed that the guard member 10b comes into contact with the right side wall surface 7a and the left side wall surface 7b. In the above specific example, as shown in FIG. 5B, the coordinates of the right end of the region Rx are the position Pea (common with the right wall surface 7a). Similarly, the coordinates of the left end of the region Ry are the position Peb (common with the left wall surface 7b). In the specific example of FIG. 5B, the coordinates of the left end of the region Rx are the position Px, and the coordinates of the left end of the region Ry are the position Py.

Originally, the white reference data is preferably generated by placing the white reference sheet 10a on the entire region R (including the region Rx and the region Ry) and irradiating the white reference sheet 10a with detection light. .. FIG. 5C shows the white reference data generated by placing the white reference sheet 10a over the entire area R.

However, as understood from FIGS. 5B and 5C, the gradation I in the region Rx and region Ry where the guard member 10b is located assumes that the white reference sheet 10a is located in the region Rx and region Ry. It is different from the gradation I in the case of. With the above pre-adjustment white reference data, there may be a problem that appropriate shading correction cannot be performed on the image data.

In consideration of the above circumstances, in the present embodiment, the gradation I in the adjustment region Ra including the region Rx in the region R can be adjusted. Further, the gradation I in the adjustment region Rb including the region Ry in the region R can be adjusted. For the sake of explanation, the region other than the adjustment region Ra and the adjustment region Rb in the region R may be described as the region Rc. The white reference sheet 10a is located in the entire area of the above region Rc (the guard member 10b is not located).

6 (a) to 6 (c) are diagrams for explaining a configuration for adjusting the pre-adjustment white reference data. FIG. 6A shows the pre-adjustment white reference data as in FIG. 5B described above. However, in the specific example of FIG. 6A, a part of the pre-adjustment white reference data including the above-mentioned region Rx (near the side wall) and the adjustment region Ra is shown.

As described above, the adjustment region Ra is a region including the region Rx in which the guard member 10b is located. Specifically, as shown in FIG. 6A, the adjustment region Ra is set from the position Pea (right side wall surface 7a) on the X-axis to the search start position Psa. The search start position Psa described above is located closer to the region Rc (white reference sheet 10a) than the left end (position Px) of the region Rx (guard member 10b). Similarly, the position from the position Peb (left side wall surface 7b) on the X-axis to the search start position Psb is set as the adjustment region Rb. The search start position Psb described above is located closer to the region Rc (white reference sheet 10a) than the left end (position Py) of the region Ry.

As described above, the adjustment area Ra to which the pre-adjustment white reference data is adjusted is defined by the search start position Psa. The search start position Psa is determined in advance in consideration of, for example, the thickness of both ends 10b in the longitudinal direction in the X-axis direction. Further, the adjustment area Rb to which the pre-adjustment white reference data is adjusted is defined by the search start position Psb. The above search start position Psb is determined in advance in consideration of, for example, the thickness of the guard member 10b in the X-axis direction. The flash memory of the banknote acceptor 100 stores the above search start position Psa and search start position Psb.

FIG. 6A shows the average gradation Iave. In the present embodiment, among the pixels Gb located in the region Rc, the pixel Gb located at the search start position Psa and the four pixels Gb continuously arranged from the pixel Gb to the region Rc side (in total). The gradation I of the five pixels Gb) is sampled. Further, the average value of the five gradations I is calculated, and the calculation result is stored as the average gradation Iave. The method of calculating the average gradation Iave is not limited to the above example. For example, the gradation I other than the above five pixels Gb may be sampled, and the average gradation Iave may be calculated from the gradation I.

Further, FIG. 6A shows a range (Iave-W ≦ I ≦ Iave + W) within the deviation threshold value W from the average gradation Iave. The above range of gradation I may be referred to as "normal range" below. In the deviation threshold W of the present embodiment, the gradation I of the pixel Gb facing the white reference sheet 10a among the pixels Gb of the adjustment region Ra is in the normal range, and the gradation of the pixel Gb in the region Rx deviates from the normal range. Predetermined in.

The banknote acceptor 100 of the present embodiment identifies a position (pixel Gb) on the X-axis where the gradation I deviates from the normal range. Specifically, in the direction of the white arrow (X-axis direction) shown in FIG. 6A, the absolute value of the difference between the gradation I and the average gradation Iave is in order from the gradation I of the search start position Psa. It is determined whether or not (hereinafter referred to as "deviation width") is larger than the deviation threshold W. In the specific example of FIG. 6A, it is first determined that the deviation width exceeds the deviation threshold value W at the position Px.

FIG. 6B is a diagram for explaining a part of the adjusted white reference data. In the specific example of FIG. 6B, a part of the white reference data near the region Rx is shown. Further, in the specific example of FIG. 6B, it is assumed that the deviation width exceeds the deviation threshold value W at the position Px, as in the specific example of FIG. 6A described above. In the above case, as shown in FIG. 6B, the gradation I of the region (region Rx) on the position Pea (right side wall surface 7a) side from the position Px is adjusted to the average gradation Iave.

FIG. 6C is a diagram for explaining the entire adjusted white reference data. In the specific example of FIG. 6C, it is assumed that the deviation width exceeds the deviation threshold value W at the position Px, as in the specific example of FIG. 6B described above. In the above case, the gradation I of the region on the position Pea side of the position Px is adjusted to the average gradation Iave. In the following, the average gradation Iave in which the gradation I of the adjustment region Ra is adjusted will be referred to as “average gradation Iave 1”.

The banknote acceptor 100 adjusts the gradation I of the adjustment area Rb in the same manner as the adjustment area Ra described above. Specifically, the banknote acceptor 100 includes a pixel Gb located at the search start position Psb and four pixels Gb (five pixels Gb in total) arranged continuously from the pixel Gb to the region Rc side. ) Gradation I is sampled. Further, the average value of the five gradations I is calculated, and the calculation result is stored as the average gradation Iave2. In addition, the average gradation Iave2 may be calculated from the gradation I other than the above five pixels Gb.

After that, in the banknote acceptor 100, the absolute value (deviation width) of the difference between the gradation I of each position (pixel Gb) and the average gradation Iave2 is larger than the deviation threshold value W from the search start position Psb to the position Peb. Judge whether or not. In the specific example of FIG. 6C, it is assumed that the deviation width is first determined to exceed the deviation threshold value W at the position Py. In the above case, the banknote acceptor 100 adjusts the gradation I from the position Py to the position Peb in the pre-adjustment white reference data to the average gradation Iave2.

After adjusting the gradation I of the adjustment area Ra and the adjustment area Rb, the banknote acceptor 100 stores the white reference data in the white reference data storage unit 105. According to the above white reference data, the image of the banknote taken in the vicinity of the side walls (7a, 7b) of the transport path 4 (adjustment area Ra, adjustment area Rb) can be appropriately shaded and corrected.

FIG. 7 is a flowchart of the pre-shipment adjustment process executed by the banknote acceptor 100. The above pre-shipment adjustment process is executed in the manufacturing process (before shipping) of the banknote acceptor 100. The banknote acceptor 100 adjusts the pre-adjustment white reference data in the pre-shipment adjustment process, and stores the adjusted white reference data in the white reference data storage unit 105.

As described above, the banknote acceptor 100 has a floor of pre-adjustment white reference data for both the adjustment area Ra (near the right side wall surface 7a) and the adjustment area Rb (near the left side wall surface 7b) in the area R through which the banknotes pass. The tone I is adjusted. The banknote acceptor 100 performs a pre-shipment adjustment process in which the gradation I of the adjustment area Ra of the adjustment area Ra and the adjustment area Rb is adjusted, and then the pre-shipment adjustment process in which the gradation I of the adjustment area Rb is adjusted. To execute. In the specific example of FIG. 7, it is assumed that the gradation I of the adjustment region Ra is adjusted in the pre-shipment adjustment process.

As shown in FIG. 7, when the pre-shipment adjustment process is started, the banknote acceptor 100 acquires the gradation I of the five pixels Gb from the pre-adjustment white reference data (S1). As described above, for example, when adjusting the gradation I of the pixel Gb in the adjustment area Ra, the left side direction (X-axis opposite direction) from the search start position Psa which is the left end (opposite side to the right side wall) of the adjustment area Ra. ), The gradation I of the five pixels Gb (that is, the pixels Gb arranged in the region Rc of FIG. 6A) is acquired. The detection light transmitted through the white reference sheet 10a is incident on each of the above pixels Gb.

After acquiring the gradation I of the five pixels Gb from the pre-adjustment white reference data, the banknote acceptor 100 calculates the average gradation Iave from the gradation I of the pixel Gb (S2). After that, the banknote acceptor 100 identifies the target pixel Gb from each pixel Gb (S3). In the first step S3, the pixel Gb located at the search start position Psa described above is specified as the target pixel Gb. Further, in the next step S3, the pixel to the right of the pixel Gb specified in the previous step S3 (one located on the right side wall surface 7a side) is specified as the target pixel Gb.

After specifying the target pixel Gb, the banknote acceptor 100 calculates the deviation width for the gradation I of the target pixel Gb. Specifically, the banknote acceptor 100 subtracts the average gradation Iave calculated in step S2 above to the gradation I of the target pixel Gb, and stores the absolute value of the subtraction result as the deviation width of the target pixel Gb. ..

After calculating the deviation width for the target pixel Gb, the banknote acceptor 100 determines whether or not the deviation width is larger than the deviation threshold value W (S5). When it is determined that the deviation width is smaller than the deviation threshold value W (S5: NO), the banknote acceptor 100 returns the process to step S3 described above. After that, the banknote acceptor 100 repeatedly executes steps S4 and S5 while changing the target pixel Gb in step S3. In the above configuration, it is repeatedly determined whether or not the deviation width of each pixel Gb is larger than the deviation threshold value W while shifting the target pixel Gb one by one in the side wall direction of the transport path 4.

When it is determined that the deviation width of the target pixel Gb is larger than the deviation threshold value W (S5: YES), the banknote acceptor 100 calculates the white reference data for each pixel from the target image Gb to the side wall of the transport path 4 on the average floor. Adjusted to tune Iave (S6). For example, when adjusting the white reference data of the adjustment region Ra near the right side wall surface 7a, the white reference data of each pixel Gb from the target pixel Gb to the right side wall surface 7a is adjusted to the average gradation Iave. After adjusting the white reference data, the banknote acceptor H ends the pre-shipment adjustment process.

<Second Embodiment>
A second embodiment of the present invention will be described below. For the elements whose actions and functions are the same as those of the first embodiment in each of the embodiments exemplified below, the reference numerals referred to in the description of the first embodiment will be diverted and detailed description of each will be omitted as appropriate.

FIG. 8A is a cross-sectional view of the banknote acceptor H according to the second embodiment. FIG. 8A corresponds to the cross-sectional view taken along the line BB shown in FIG. 1A of the first embodiment described above. However, in FIG. 8A, the first image sensor 6a, the second image sensor 6b, the lower cover 7, and the upper tray 8 are excerpted from each configuration of the banknote acceptor 100. Further, FIG. 8A shows an optical path of the detection light emitted from the light emitting element Ga by a broken line arrow.

As shown in FIG. 8A, the upper tray 8 is provided with a guide portion 8L and a guide portion 8R. The guide portion 8R has a substantially plate shape and is erected along the right side wall (7a) of the transport path 4. As shown in FIG. 8A, the lower end of the guide portion 8R is located on the bottom surface side of the transport path 4 from the contact surface (S shown in FIG. 8A) with the lower cover 7 of the upper tray 8. The lower end of the guide portion 8R is in contact with the vicinity of the right end of the bill placed on the bottom surface of the transport path 4, and restricts the movement of the bill in the upper direction (Z-axis direction).

The guide portion 8L has a substantially plate shape like the guide portion 8R, and is erected along the left side wall (7b) of the transport path 4. Further, as shown in FIG. 8A, the lower end of the guide portion 8L is located on the bottom surface side of the transport path 4 from the contact surface S with the lower cover 7 in the upper tray 8, and is placed on the bottom surface of the transport path 4. It comes into contact with the vicinity of the left end of the bill and restricts the movement of the bill in the upward direction.

Suppose that the guide portion 8 (R, L) is not provided in inverse proportion. In the above inverse proportion, the left end or the right end of the bill may move to the above-mentioned contact surface S (floating occurs). In the above case, it is said that the possibility that the end portion of the bill enters between the upper tray 8 and the lower cover 7, the bill becomes immovable in the transport path 4, and the bill is jammed is not completely eliminated. There is an inconvenience. According to the guide portions 8 (R, L) of the second embodiment, as described above, since the floating of the left and right ends of the bill is suppressed, there is an advantage that the above-mentioned inconvenience is suppressed.

The guide unit 8 (R, L) of the second embodiment is provided in the area R (see FIG. 5A described above) in which an image used for discriminating banknotes is captured. The above configuration has an advantage that the banknote acceptor H can be easily miniaturized as compared with a configuration in which the guide portions 8 (R, L) are provided outside the region R, for example.

However, the member located between the light emitting element Ga of the first image sensor 6a and the pixel Gb of the second image sensor 6b needs to transmit light transmission. In consideration of the above circumstances, the guide portion 8 (R, L) is formed of a light-transmitting member (for example, a transparent resin) like the upper tray 8.

However, when the transparent guide portion 8 (R, L) is provided in the region R, a new problem that the detection light is refracted by the guide portion 8 (R, L) may occur. That is, the guide unit 8 (R, L) may cause a problem that the optical path of the detection light deviates from the original optical path. Further, when the above problem occurs, there may be a disadvantage that the white reference data used for shading correction of the image data is not appropriately generated.

For example, the detection light emitted from the light emitting element Ga located directly above the guide unit 8R should originally be incident on the pixel Gb located directly below the guide unit 8R. However, as shown in FIG. 8A, for example, when the detection light emitted from the light emitting element Ga is refracted by the guide unit 8R, a pixel Gb different from the pixel Gb that should originally be incident (for example, an adjacent pixel Gb) The detection light may be incident on the. In the above case, the gradation I of the white reference data (white reference data before adjustment) in the pixel Gb to which the detection light should originally be incident is smaller than the original gradation I (when the guide portion 8R is not provided). On the other hand, the gradation I of the white reference data in the other pixel Gb is larger than the original gradation I.

FIG. 8B is a diagram for explaining the pre-adjustment white reference data in the second embodiment. FIG. 8B shows the gradation I of the detection light incident on the second image sensor 6b at each position on the X-axis of the region R (the region between the side walls of the transport path 4).

In the above-described first embodiment, the white reference data is generated by irradiating the white reference member 10 (see FIG. 3) with the detection light. In the second embodiment, the white reference member 10 is not placed in the transport path 4 (region R) when the white reference data is generated. In the above second embodiment, since it is not necessary to place the white reference member 10 on the transport path 4 when generating the white reference data, the period after the manufacturing process of the banknote acceptor H (the period during which it operates in the market). ), White reference data can be generated periodically. For example, white reference data can be generated each time the power of the banknote acceptor H is turned on.

The gradation I of the detection light emitted from the light emitting element Ga is about 1/10 of that when the white reference paper (for example, the above-mentioned white reference sheet 10a) is transmitted and when the white reference paper is not transmitted. In consideration of the above circumstances, in the second embodiment, the white reference data in which the gradation of each pixel Gb is 1/10 is stored in the white reference data storage unit 105.

As shown in FIG. 8B, in the second embodiment, the position on the X-axis of the right wall surface 7a (right end of the region R) of the transport path 4 is referred to as “position Pea” as in the first embodiment described above. Describe. Further, the position on the X-axis of the left side wall surface 7b (left end of the region R) of the transport path 4 is described as "position Peb".

Further, in the second embodiment, as in the first embodiment described above, the pre-correction white reference data of the pixel Gb of the adjustment region Ra near the right side wall of the transport path 4 and the adjustment region Rb near the left side wall is adjusted. .. Specifically, for a pixel Gb in which the absolute value (deviation width) of the difference between the average gradation Iave and the gradation I is larger than the deviation threshold value W, the gradation I of the pixel Gb is adjusted to the average gradation Iave.

In the specific example of FIG. 8B, when viewed from the center of the region R toward the position Pea (right side wall), the deviation width of the pixel Gb at the position Px first becomes larger than the deviation threshold value W. In the above specific example, the pre-adjustment white reference data from the position Px to the position Pea is adjusted to the average gradation Iave. Similarly, when viewed from the center of the region R toward the position Peb (left wall), the deviation width of the pixel Gb at the position Py first becomes larger than the deviation threshold value W. In the above specific example, the pre-adjustment white reference data from the position Py to the position Peb is adjusted to the average gradation Iave.

FIG. 8C is a diagram for explaining the adjustment region Ra in the second embodiment. FIG. 8 (c) shows the pre-adjustment white reference data as in FIG. 8 (b) described above. However, in the specific example of FIG. 8C, a part of the pre-adjustment white reference data including the adjustment region Ra is shown.

As shown in FIG. 8 (c), the adjustment region Ra is a predetermined region from the position Psa to the position Pea (right side wall), as in the first embodiment described above. The above position Psa is preset in consideration of the shape of the guide portion 8R and the refractive index (range affected by the refraction of the detection light). Similarly, the adjustment region Rb is a predetermined region from the position Psb to the position Peb (left wall), as in the first embodiment described above. The above positions Psb are preset in consideration of the shape and refractive index of the guide portion 8L.

FIG. 8D is a diagram showing white reference data in which the gradation I of the adjustment region Ra is adjusted in the specific example of FIG. 8C described above. In the specific example of FIG. 8D, it is assumed that the gradation I from the position Px to the position Pea is adjusted to the average gradation Iave. The gradation I of the adjustment region Rb is adjusted by the same method as that of the adjustment region Ra. The banknote acceptor H multiplies the gradation I of the entire region of the pre-adjustment white reference data in which the gradation I of the adjustment region Ra and the adjustment region Rb is adjusted by 1/10 and stores it as the white reference data.

Also in the above-mentioned second embodiment, the same effect as that of the above-mentioned first embodiment can be obtained. The position where the guide portion (8R, 8L) is provided can be changed as appropriate. For example, a guide portion may be provided on the upper surface 7d of the lower cover 7. Further, in the second embodiment, the guide portion is provided near the side wall of the transport path 4, but may be provided near the center of the transport path 4. In the above case, the area including the guide portion provided near the center is set as the adjustment area, and the white reference data of the pixel Gb located in the adjustment area is adjusted.

<Third Embodiment>
In the above-described first embodiment, the white reference member 10 (see FIG. 3A) is actually used in shading correction from the pre-adjustment white reference data obtained in the state of being placed on the region R of the transport path 4. White reference data was determined. Further, in the second embodiment, before the adjustment (obtained by directly irradiating the pixel Gb with the detection light from the light emitting element Ga) obtained in a state where the white reference member 10 is not placed in the region R of the transport path 4. The white reference data was determined from the white reference data.

Hereinafter, for the sake of explanation, the pre-adjustment white reference data obtained with the white reference member 10 mounted may be referred to as "first pre-adjustment data". Further, the pre-adjustment white reference data obtained in a state where the white reference member 10 is not placed may be described as "second pre-adjustment data". Although the details will be described later, in the third embodiment, the white reference data D (see FIG. 9C described later) is determined using both the first pre-adjustment data and the second pre-adjustment data.

9 (a) to 9 (c) are diagrams for explaining the third embodiment. The banknote acceptor 100 of the third embodiment includes a region R (including Rx and Ry) through which the banknotes pass, as in the first embodiment described above. As described above, the region Rx of the region R is a region near the right side wall surface 7a. Further, the region Ry in the region R is a region near the left side wall surface 7b. Hereinafter, for the sake of explanation, the region R other than the region Rx and the region Ry will be referred to as “region Rz”. The above region Rz is a region including the center of the region R.

The banknote acceptor 100 of the third embodiment is provided with N pixels G. Specifically, N pixels G are provided in a row in the order of pixel G1, pixel G2 ... pixel GN from the left side wall surface 7b to the right side wall surface 7a. For example, of the N pixels G, n pixels G from the pixel G1 to the pixel Gn are provided in the region Ry. Further, N-2n pixels G from pixel G (n + 1) to pixel G (Nn) are provided in the region Rz, and n pixels G from pixel G (Nn + 1) to pixel GN are in the region Rx. It will be provided. In the third embodiment, the i-th pixel G viewed from the left side wall surface 7b may be described as "pixel Gi" (1 ≦ i ≦ N).

FIG. 9A is a diagram for explaining the first pre-adjustment data. The first pre-adjustment data is substantially the same as the pre-adjustment white reference data shown in FIG. 5 (b) of the first embodiment described above.

Specifically, the pixels G (n + 1) to the pixels G (Nn) of the region Rz in the region R face the white reference sheet 10a of the white reference member 10. Therefore, the gradation of the data before the first adjustment of each pixel G in the region Rz (hereinafter, may be referred to as “gradation Ia”) can be adopted as the white reference data. On the other hand, in the region R, the pixels G1 to the pixels Gn of the region Ry face the guard member 10b of the white reference member 10. Therefore, the gradation Ia in the region Ry is not suitable as white reference data. The gradation Ia in the region Rx of the region R is also not suitable as white reference data, like the gradation Ia in the region Ry.

FIG. 9B is a diagram for explaining the second pre-adjustment data. The second pre-adjustment data is substantially the same as the pre-adjustment white reference data shown in FIG. 8 (b) of the second embodiment described above. However, in the third embodiment, even if the pixel G is irradiated with the detection light stronger than the predetermined gradation (hereinafter, “upper limit gradation Im”), the data before the second adjustment of the pixel G is the upper limit gradation. Become Im.

As shown in FIG. 9B, the data before the second adjustment in the region Rz of the region R has the upper limit gradation Im. On the other hand, in the region Rx and the region Ry of the region R, the detection light is refracted by the guide unit 8 as described above. Therefore, the gradation of the data before the second adjustment of each pixel G in the region Rx and the region Ry (hereinafter, may be referred to as “gradation Ib”) is set to the upper limit gradation Im as shown in FIG. 9B. It may not be.

In the above configuration, when the gradation of the actual detection light is stronger than the upper limit gradation Im, the second pre-adjustment data in the region Rz is different from the gradation of the actual detection light. On the other hand, the data before the first adjustment in the region Rz shows the gradation of the actual detection light. Therefore, it is desirable that the gradation of each pixel G in the region Rz is corrected by the white reference data obtained from the first pre-adjustment data rather than by the white reference data obtained from the second pre-adjustment data.

Further, as described above, the first pre-adjustment data in the region Rx and the region Ry is not suitable as white reference data. Therefore, the gradation of each pixel G in the region Rx and the region Ry is corrected by the white reference data obtained from the second pre-adjustment data rather than by the white reference data obtained from the first pre-adjustment data. desirable. By correcting the gradation of each pixel G of the area Rx and the area Ry with the white reference data obtained from the data before the second adjustment, the gradation of the pixel G that does not face the bill is corrected to the upper limit gradation Im. The gradation of the pixel G that does not face the bill is corrected to be less than the upper limit gradation Im. Therefore, there is an advantage that the outer edge of the bill can be easily detected.

In consideration of the above circumstances, in the white reference data of the third embodiment, the white reference data for correcting the gradation of each pixel G in the region Rz is determined from the data before the first adjustment, and each of the region Rx and the region Ry. The white reference data for correcting the gradation of the pixel G adopts a configuration determined from the data before the second adjustment.

FIG. 9C is a conceptual diagram of the white reference data D in the third embodiment. The white reference data D is configured to include N correction values d. Each correction value d corresponds to any of the pixels G. Hereinafter, the correction value d corresponding to the pixel Gi is described as “correction value di”. Assuming that the gradation of the pixel Gi before correction is the measured gradation Ivi (1 ≦ i ≦ N), the gradation of the pixel Gi after the shading correction (hereinafter referred to as “correction gradation Ici”) is the measured gradation. It is obtained by multiplying Ivi by the correction value di (Ici = Ivi × di).

Each of the above correction values d is a correction value d determined from the first pre-adjustment data (see FIG. 9A) and a correction value d determined from the second pre-adjustment data (see FIG. 9B). And include. In the above configuration, the white reference data D pixels the correction value d (first correction value) obtained by irradiating the white reference member 10 with the detection light and the detection light not transmitted through the white reference member 10. It is also said that the composition includes the correction value d (second correction value) obtained by irradiating G (light receiving means).

For example, in the second pre-adjustment data, the correction value d1 is determined from the gradation Ia1 of the pixel G1 in the region Ry. Similarly, in the second pre-adjustment data, the correction value dn is determined from the correction value d2 from each gradation Ia (Ia2 to Ian) of the pixels G2 to the pixel Gn in the region Ry. Further, in the second pre-adjustment data, the correction value d (Nn + 1) is determined from the gradation Ia (Nn + 1) of the pixel G (Nn + 1) in the region Rx. Similarly, in the data before the second adjustment, from the pixel G (Nn + 2) of the region Rx to each gradation Ia (Ia (Nn + 2) to IaN) of the pixel GN, from the correction value d (Nn + 2). The correction value dN is determined.

As understood from the above description, the correction value d corresponding to each pixel G of the region Rx and the region Ry is determined from the data before the second adjustment. Specifically, the correction value di corresponding to each pixel G of the region Rx and the region Ry (in the case of 1 ≦ i ≦ n, N−n ≦ i ≦ N) has an upper limit of the gradation Ibi of the second pre-adjustment data. It is obtained by dividing by the gradation Im (di = Im / Ibi).

On the other hand, the correction value d corresponding to each pixel G in the region Rz is determined from the data before the first adjustment. Specifically, in the first pre-adjustment data, the correction value d (n + 1) is determined from the gradation Ia (n + 1) of the pixel G (n + 1) in the region Rz. Similarly, in the data before the first adjustment, the correction value d is obtained from each gradation Ia (Ia (n + 2) to Ia (Nn)) of the pixel G (n + 2) to the pixel G (Nn) in the region Rz. The correction value d (N−n) is determined from (n + 2). Specifically, assuming that the gradation I to be white is the white gradation Iw, the correction value di corresponding to each pixel G in the region Rz (in the case of n + 1 ≦ i ≦ Nn-1) is before the first adjustment. It is obtained by dividing the gradation Iai of the data by the white gradation Iw (di = Iw / Iai).

The pixel G whose correction value d is determined from the first pre-adjustment data and the pixel G whose correction value d is determined from the second pre-adjustment data can be appropriately changed. For example, the correction value of the pixel G in a region wider than the region Rz may be determined from the data before the first adjustment.

The paper leaf discrimination device of the present invention is, for example, the following paper leaf discrimination device.

The paper leaf discrimination device (100) of the present invention includes a transport means (transport control unit 101) for moving the paper leaf along the transport path (4) and a light emitting means for irradiating one surface of the moving paper leaf with detection light. (Light emitting element Ga) and the detection light that is arranged at a position facing the other surface of the moving paper leaf and has passed through the paper leaf, and has a width orthogonal to the moving direction (Y-axis direction) of the paper leaf. A plurality of light receiving means (pixels Gb) arranged along the directions (X-axis direction, scanning axis direction) and an image data generating means (image data) for generating gradation image data according to the detection light incident on the light receiving means. White reference data storage means (white reference data storage unit 105) that stores white reference data obtained by irradiating the generation unit 104) and the white reference member (10) used for shading correction of image data with detection light. ), The movement restricting means (right side wall surface 7a, left side wall surface 7b) located at the widthwise end of the transport path and forming the side wall of the transport path, and the specific area (the width direction position of the light receiving means) is predetermined. Adjustment means (adjustment unit 109) that adjusts the white reference data for shading correction of the image data of the light receiving means to a predetermined value (average gradation Iave) under the condition that it is within the adjustment area Ra and adjustment area Rb). And. According to the above configuration, the image of the paper leaf is appropriately shaded and corrected.

As a preferred embodiment of the present invention, the specific region is a region in which the distance in the width direction to the movement regulating means is a predetermined distance (distance from Psa to Pea in FIG. 5 or distance from Psb to Peb) or less. It is characterized by that. Further, as another preferred embodiment of the present invention, a contact means (guide) provided between the light emitting means and the light receiving means, which comes into contact with one or the other surface of the paper sheet and is formed of a member which transmits light. The position on the width direction of the contacting means is located in a specific region.

1 ... Lower unit, 10 ... White reference member, 10a ... White reference sheet, 10b ... Guard member, 2 ... Upper unit, 3a ... Insert port, 3b ... Intake port, 4 ... Transport path, 5 ... Transport device, 5a ... Lower transport member, 5a ... Transport part, 5b ... Upper transport member, 6a ... 1st image sensor, 6b ... 2nd image sensor, 6c ... Magnetic sensor, 7 ... Lower cover, 7a ... Right side wall surface, 7a ... Right side wall surface , 7b ... left wall surface, 7c ... recess, 7d ... top surface, 8 ... guide part, 8 ... upper tray, 8L ... guide part, 8R ... guide part, 8a ... recess, 8b ... bottom surface, 9 ... white reference for reflection One piece, 100 ... Bill discrimination device, 101 ... Transport control unit, 102 ... Sensor unit, 103 ... Sensor control unit, 104 ... Image data generation unit, 105 ... White reference data storage unit, 106 ... Correction unit, 107 ... White reference data Generation unit, 108 ... Adjustment position determination unit, 109 ... Adjustment unit, 10b` ... Both ends in the longitudinal direction.

Claims (6)

A transport means for moving paper sheets along the transport path,
A light emitting means for irradiating one surface of the moving paper sheet with detection light,
The detection light that is arranged at a position facing the other surface of the moving paper leaf and has passed through the paper leaf is received, and a plurality of light receiving signals are arranged along the width direction orthogonal to the moving direction of the paper leaf. Means and
An image data generation means for generating image data having a gradation corresponding to the detection light incident on the light receiving means, and an image data generation means.
A white reference data storage means for storing the white reference data obtained by irradiating the white reference member used for shading correction of the image data with the detection light, and
A movement restricting means located at the widthwise end of the transport path and forming a side wall of the transport path.
The position in the width direction is within a predetermined specific region, is provided between the light emitting means and the light receiving means, and is formed of a member that abuts on one or the other surface of the paper sheet and transmits light. Contact means and
On condition that the widthwise position of said light receiving means is the specific region, the paper comprising the white reference data for shading correction of the image data of the light receiving means, and adjusting means for adjusting the predetermined value, the Leaf discrimination device. The paper sheet discriminating device according to claim 1, wherein the specific region is a region in which the distance in the width direction to the movement regulating means is a predetermined distance or less. A transport means for moving the paper leaf along the transport path, a light emitting means for irradiating one surface of the moving paper leaf with detection light, and a paper arranged at a position facing the other surface of the moving paper leaf. In addition to receiving the detection light that has passed through the leaf, a plurality of light receiving means arranged along the width direction orthogonal to the moving direction of the paper leaf and the gradation corresponding to the detection light incident on the light receiving means. An image data generating means for generating image data, a movement restricting means located at the widthwise end of the transport path and forming a side wall of the transport path, and the widthwise position within a predetermined specific area. In a paper leaf discriminating device provided between the light emitting means and the light receiving means, the contact means which abuts one surface or the other surface of the paper sheet and is formed of a member which transmits light . , A method of adjusting white reference data used for shading correction of the image data.
On condition that the widthwise position of said light receiving means is the specific region, the white reference data comprising the white reference data for shading correction of the image data of the light receiving means, a step of adjusting to a predetermined value, the Adjustment method. The transport means for moving the paper leaf along the transport path, the light emitting means for irradiating one surface of the moving paper leaf with detection light, and the paper arranged at a position facing the other surface of the moving paper leaf. In addition to receiving the detection light that has passed through the leaf, a plurality of light receiving means arranged along the width direction orthogonal to the moving direction of the paper leaf and the gradation corresponding to the detection light incident on the light receiving means. The image data generating means for generating image data, the movement restricting means located at the widthwise end of the transport path and forming the side wall of the transport path, and the widthwise position within a predetermined specific area. In a paper leaf discriminating device provided between the light emitting means and the light receiving means, the paper leaf discriminating device includes a contacting means which is provided between the light emitting means and the light receiving means and is formed of a member which abuts one or the other surface of the paper sheet and transmits light . , A program that causes a computer to adjust the white reference data used for shading correction of the image data.
On condition that the widthwise position of said light receiving means is the specific region, program the white reference data for shading correction of the image data of the light receiving means, causes a computer to function as an adjustment means for adjusting the predetermined value .. A transport means for moving paper sheets along the transport path,
A light emitting means for irradiating one surface of the moving paper sheet with detection light,
The detection light that is arranged at a position facing the other surface of the moving paper leaf and has passed through the paper leaf is received, and a plurality of light receiving signals are arranged along the width direction orthogonal to the moving direction of the paper leaf. Means and
An image data generation means for generating image data having a gradation corresponding to the detection light incident on the light receiving means, and an image data generation means.
A white reference data storage means for storing white reference data used for shading correction of the image data is provided.
The white reference data is obtained by irradiating the light receiving means with the first correction value obtained by irradiating the white reference member with the detection light and the detection light not transmitted through the white reference member. and a second correction value only contains was,
The image data of the light receiving means whose width direction position is outside the predetermined specific region is shaded and corrected by using the first correction value, and the light receiving means whose width direction position is within the specific region. A paper leaf discrimination device further comprising a correction unit for shading correction of the image data of the above using the second correction value . The transport means for moving the paper leaf along the transport path, the light emitting means for irradiating one surface of the moving paper leaf with detection light, and the paper arranged at a position facing the other surface of the moving paper leaf. In addition to receiving the detection light that has passed through the leaf, a plurality of light receiving means arranged along the width direction orthogonal to the moving direction of the paper leaf and the gradation corresponding to the detection light incident on the light receiving means. Shading correction of the image data is performed in a paper sheet discrimination apparatus including an image data generating means for generating image data and a white reference data storage means for storing white reference data used for shading correction of the image data. It ’s a correction method,
The white reference data is obtained by irradiating the light receiving means with the first correction value obtained by irradiating the white reference member with the detection light and the detection light not transmitted through the white reference member. Including the second correction value
The image data of the light receiving means whose width direction position is outside the predetermined specific region is shaded and corrected by using the first correction value, and the light receiving means whose width direction position is within the specific region. The step of shading-correcting the image data of the above using the second correction value.
A correction method comprising.

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