JP3766449B2 - Paper sheet reader - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a paper sheet reader that performs authenticity and type determination of banknotes, gift certificates, and other paper sheets, and counts the number of sheets.
[0002]
[Prior art]
Paper sheet readers have been developed to handle a large amount of banknotes quickly in the financial industry, etc., and it is necessary to accurately perform authenticity judgment, type judgment and counting of the number of paper sheets such as banknotes on behalf of humans. Therefore, high reliability is required.
[0003]
A conventional paper sheet reader is configured to automatically analyze a video signal obtained by illuminating a paper sheet with a light source such as a tungsten lamp and photographing the paper sheet with a video camera.
[0004]
Here, in order to maintain the analysis accuracy, it is desirable to perform analysis based on a video signal obtained by photographing under a predetermined photographing condition.
[0005]
Therefore, the configuration is such that a sheet to be processed is mounted in a shielding case for shielding the incidence of external light, and photographing is performed in a state in which the incidence of external light is prevented. More specifically, the shielding case is provided with an opening / closing lid for inserting and removing paper sheets. After a plurality of paper sheets are bundled and attached, the reading process is performed with the opening / closing lid closed and shielded from light. When started, the video camera can always shoot under certain conditions without being affected by external light under a certain illuminance of an illumination light source provided in the shielding case.
[0006]
[Problems to be solved by the invention]
However, when the operator becomes busy, for example, the opening / closing operation of the opening / closing lid becomes troublesome, and the operator tends to start the reading operation with the opening / closing lid open. A situation in which the reading operation is performed under the influence of the external light from the installed indoor lighting, which causes a decrease in reading accuracy, frequently occurs, and this is a problem in view of the importance of business. It was.
[0007]
The present invention has been made in view of such problems, and an object of the present invention is to provide a paper sheet reading apparatus capable of improving operability without causing a decrease in reading accuracy.
[0008]
[Means for Solving the Problems]
  In order to achieve such an object, the present invention provides a paper sheet reading apparatus that sequentially switches one or two or more paper sheets and sequentially reads them.Timing means for detecting the timing at which each sheet to be read changes, and in synchronization with the detection timing of the timing meansIllumination light of a predetermined wavelengthTurn onOn paperLighting lightIrradiateBy light emitting diodeAn illumination light source, a wavelength selection filter that selects a wavelength component of a specific wavelength band of illumination light from a reflected light image from a paper sheet, and reflected light that enters through the wavelength selection filter in synchronization with the detection timing of the timing means An image pickup means for picking up an image,The wavelength selection filter is disposed in front of the imaging unit so as to selectively pass the wavelength component of the specific wavelength band of the illumination light in the reflected light image from the paper sheet, and the imaging unit is synchronized with the detection timing of the timing unit. And a CCD solid-state imaging device that captures the reflected light image for a predetermined period after discharging unnecessary chargesThe configuration.
[0009]
Further, the wavelength selection filter is a bandpass filter that selects a wavelength component of a specific wavelength band of the illumination light from the reflected light image from the paper sheet, or the illumination light of the reflected light image from the paper sheet. A long wavelength selection filter that selects a long wavelength component that is greater than or equal to a wavelength component in a specific wavelength band, or a short wavelength that selects a short wavelength component that is less than or equal to the wavelength component of the specific wavelength band of the illumination light from the reflected light image from the paper sheet. It consisted of any one of the selection filters.
[0012]
[Action]
  In the paper sheet reading device of the present invention, the illumination light source isIlluminates the paper with illumination light of a predetermined wavelength band for reading processingAfter the image pickup means discharges unnecessary charges,The reflected light image from the paper sheet by the illumination lightPlaced in front of the imaging meansImaging is performed through a wavelength selection filter having specific wavelength characteristics. In addition, in synchronization with the detection timing by the timing meansThe illumination light source illuminates the paper and the imaging meansBy performing imaging, imaging is performed in synchronization with switching to the paper sheet that is the imaging target.In addition, since the illumination light source is composed of light emitting diodes with good response characteristics (switching characteristics), it is possible to achieve short-time exposure. As a result, a high-speed shutter function is exhibited and imaging blur is greatly reduced. In addition, the power consumption accompanying the improvement of the light emission efficiency can be greatly reduced.
[0013]
  In addition, by applying a CCD solid-state imaging device and capturing images for a predetermined period in synchronism with the detection timing, a high-speed electronic shutter function is exhibited, and the occurrence of imaging blurring is suppressed and power consumption is reduced. Yes.In addition, by providing a wavelength selection filter in front of the image pickup means, the external light component including the wavelength component of the illumination light of the illumination light source is removed from the reflected light from the paper sheet, so that the image is taken. Therefore, it is possible to take an image in an optimum exposure state by removing the influence of the external light from the indoor lighting installed in the area, and as a result, it is possible to perform a true / false determination with high accuracy.
[0014]
【Example】
Hereinafter, a first embodiment of a paper sheet reading device according to the present invention will be described with reference to the drawings. The configuration of the apparatus will be described based on the block diagram of FIG. 1. A feeding mechanism 2 for bundling and feeding a plurality of paper sheets (banknotes or the like) has a turning mechanism for rolling the fed paper sheets one by one. (Not shown) is provided. Since the turning mechanism is not directly related to the present invention, a detailed description is omitted.
[0015]
Further, the input unit 2 includes an illumination light source 6 that illuminates the surface of the input paper sheet 4 with a uniform illuminance, an imaging optical system 8 that receives reflected light from the paper sheet 4 by the illumination light, and a CCD solid-state imaging. A device 9 is provided.
[0016]
The illumination light source 6 is a light source for exposing the surface of the paper sheet just after being beaten, and has a center wavelength of about 550 nm and a half-value width of about 500 nm to about 600 nm as shown by a characteristic curve G shown by a solid line in FIG. A plurality of green light emitting diodes having a wavelength band in the range of 1 are arranged on the light emitting surface, and light is emitted by driving power supplied from a driving circuit 15 described later to illuminate the paper sheet 4. .
[0017]
  The imaging optical system 8 condenses the reflected light from the paper sheet 4 to form an image on the imaging surface of the CCD solid-state imaging device 9, and between the optical lens group 8 a and the CCD solid-state imaging device 9. Inserted intoArranged in front of the CCD solid-state imaging device 9 so as to selectively pass the wavelength component of the specific wavelength band in the reflected light from the paper sheet 4The light transmission filter 8b further includes a wavelength component having a center wavelength of about 550 nm and a half-value width in a range of about 500 nm to about 600 nm as shown in FIG. 9 has a wavelength selection characteristic to be transmitted to 9. That is, the light transmission type filter 8b transmits the reflected light having a wavelength component substantially equal to the wavelength band of the illumination light from the illumination light source 6, and has a so-called band-pass filter characteristic that blocks transmission of wavelength components outside the wavelength band. Have. In FIG. 4, the characteristic indicated by the solid line is the actual transmittance characteristic, and the characteristic indicated by the dotted line is the normalized transmittance characteristic when the maximum transmittance is 100%.
[0018]
The CCD solid-state imaging device 9 is an area image sensor in which a large number of fine pixels having a photoelectric conversion function are two-dimensionally arranged, and is synchronized with drive control signals S3, S4, and S5 supplied from a timing circuit 14 described later. Then, the reflected light image (subject image) is imaged, and a pixel signal S6 ′ obtained by the imaging is output.
[0019]
Further, the input unit 2 emits light by the electric power supplied from the driving circuit 12 and illuminates the surface of the paper sheet 4, and a photo that receives the reflected light reflected by the surface of the paper sheet 4. A light receiving element 11 such as a diode is provided. The red light emitting diode 10 emits light having a wavelength band with a center wavelength of about 650 nm and a half-value width of about 600 nm to about 700 nm as shown by a characteristic curve R shown by a one-dot chain line in FIG. The light receiving element 11 has light receiving sensitivity in a wavelength band substantially equal to that of the red light emitting diode 10.
[0020]
The waveform shaping circuit 13 shapes a photoelectric conversion signal S0 output from the light receiving element 11 to shape a binary logic signal (hereinafter referred to as a trigger signal) S1 representing the timing when the paper sheet 4 is rolled. Generated and transferred to the timing circuit 14. That is, every time the paper sheets 4 are rolled one by one, the intensity of the reflected light to the light receiving element 11 is greatly changed by the edge portion of each paper sheet, and when it is not rolled, the light intensity from the surface of each paper sheet is the highest. Therefore, the waveform of the photoelectric conversion signal S0 changes in accordance with the received light intensity of the reflected light, and the waveform shaping circuit 13 is built in. By detecting when the waveform of the photoelectric conversion signal S0 greatly fluctuates by a filter circuit or the like, a trigger signal S1 indicating the timing when each paper sheet is rolled is generated.
[0021]
The timing circuit 14 outputs the drive control signal S2 to the drive circuit 15 in synchronization with the trigger signal S1, thereby causing the illumination light source 6 to emit light only during the period specified by the drive control signal S2. Although details will be described later, each time a sheet is rolled and the surface of the next sheet appears, the surface of the sheet is illuminated for a certain period τ1.
[0022]
Further, the timing circuit 14 captures the surface of the paper sheet 4 by supplying various drive control signals S3, S4, and S5 to the CCD individual imaging device 9 in synchronization with the trigger signal S1. The video process circuit 16 receives the pixel signal S6 'output from the CCD individual imaging device 9, forms a video signal S6 from the pixel signal S6', and transfers it to the image identification circuit 17.
[0023]
The image identification circuit 17 performs feature extraction processing on the video signal S6 corresponding to one frame image or one field fraction to create feature data of the captured paper sheet, and to authenticate the characteristic of the paper sheet. Is compared with the feature data, and the authenticity of the paper sheet is determined, and the determination data S7 is output.
[0024]
Although not shown in the figure, when judgment data S7 representing a fake paper sheet is output, an alarm mechanism or the like is provided, such as sounding an alarm device or stopping the paper sheet reading operation by the turning mechanism. ing.
[0025]
Next, the operation will be described based on the timing chart of FIG.
First, when an operator bundles a plurality of paper sheets 4 and attaches them to the input unit 2 and starts the reading process, the red light emitting diode 10 is continuously turned on, and then the turning mechanism starts to turn each paper sheet.
[0026]
The waveform shaping circuit 13 generates a binary logic trigger signal S1 each time a photoelectric conversion signal S0 indicating whether a sheet is rolled or not is output from the light receiving element 11. In this embodiment, the trigger signal S1 is a rectangular wave signal that is inverted from logic “L” to “H” at the time when one sheet is loaded and then inverted to logic “L” again after a predetermined time. .
[0027]
The timing circuit 14 supplies the illumination drive signal S2 to the drive circuit 15 in synchronization with the timing at which the trigger signal S1 is inverted to logic “H”, thereby turning on the illumination light source 6 for a predetermined period τ1. In this embodiment, τ1 = 200 μsec is set, and illumination with green light having a center wavelength of about 550 nm is performed in this period τ1.
[0028]
Further, in synchronization with the trigger signal S1, the charge discharge signal S2 is supplied to the CCD individual imaging device 9, and the CCD individual imaging device 9 is not required in a very short time when the charge discharge signal S2 becomes logic “H”. The accumulated charge is discharged to the outside. That is, the pixel signal (charge) accumulated in the CCD individual imaging device 9 before starting the illumination by the illumination light source 6 is not necessary for the original reading process, and is thus discharged in advance before starting the next reading process.
[0029]
Then, after the unnecessary charge discharging process is completed, the timing circuit 13 supplies the charge accumulation signal S4 to the CCD solid-state imaging device 9 for a predetermined period τ2, thereby imaging the surface of the paper sheet. Here, the period τ2 is set to an exposure period that is substantially equal to the period τ1 in which the light source 6 is turned on, but actually, it is set to an exposure period that is somewhat longer than that. Therefore, the lighting period τ1 is a substantial exposure time, and the lighting time τ1 is set to 200 μsec as described above. Therefore, an extremely high-speed electronic shutter function is exhibited, and the paper sheet moves during turning. However, it is possible to reliably capture an image of a paper sheet without blurring.
[0030]
Further, as described above, since the light transmission type filter 8b transmits only the green light component of the predetermined wavelength, the CCD solid-state imaging device 9 captures only the image of this wavelength component in the reflected light from the paper sheet. Therefore, even if external light enters the input unit 2 from the fluorescent lamp 100 or the like installed in an office or the like, a wavelength component outside the transmission wavelength band of the light transmission filter 8b, that is, an unnecessary noise component is removed. . As shown in FIG. 5, a general white fluorescent lamp has a wavelength component in the range of about 400 nm to about 800 nm. Therefore, the CCD solid-state imaging device 9 also receives light from the white fluorescent lamp. However, since only the wavelength component substantially equal to that of the illumination light source 6 is received, the influence of the indoor lighting installed in the office or the like can be removed as a result, and the noise component due to outside light can be reduced. Can be removed.
[0031]
Next, when the exposure in the period τ2 is completed, a read drive signal S5 for reading the pixel charge from the timing circuit 13 to the CCD solid-state imaging device 9 is supplied, and the period in which the signal S5 is logic “H”. The pixel signal S6 ′ for each pixel is output to the video process circuit 16 in a so-called dot-sequential manner, and the video process circuit 16 transfers the video signal S6 to the identification circuit 17 as the video signal S6 based on the pixel signal S6 ′ in real time.
[0032]
Then, after the identification circuit 17 extracts the feature of the paper sheet based on the video signal S6, it compares the reference data stored in advance with this feature data, thereby determining the authenticity of the paper sheet and the number of read sheets. Counting processing is performed, and further data S7 indicating the result of the true / false judgment and the count value is output. Then, the reading process for the next sheet is repeated in the same manner.
[0033]
As described above, according to this embodiment, light that is substantially equal to the wavelength component of the irradiation light of the illumination light source 6 among the reflected light from the paper sheet is selected by the light transmission type filter 8b, and the CCD solid-state imaging device 9 is used. Since the imaging is performed, the influence of the external light from the indoor lighting 100 installed in the office or the like is removed, and it is possible to take a picture in an optimal exposure state. False determination can be made.
[0034]
Further, the wavelength component of the external light from the room illumination 100 has a wide wavelength band as shown in FIG. 5, while the wavelength component of the illumination light from the illumination light source 6 is a narrow wavelength band as shown by the solid line G in FIG. It is limited to. Accordingly, the light component transmitted through the light transmissive filter 8b is mainly composed of the light component of the illumination light, so that the CCD solid-state image pickup device 9 can perform imaging under almost constant exposure environment, and identification is performed. The circuit 17 can perform true / false judgment with high accuracy. In this embodiment, among the light intensities of the light image received by the CCD solid-state imaging device 9, the light intensity I2 of the light component due to the external light relative to the light intensity I1 of the light component due to the illumination light is relatively set to I2 / I1. = It was confirmed by experiment that it can be reduced to 1/20.
[0035]
In addition, since the illumination light source 6 is composed of a group of green light emitting diodes with good response characteristics (switching characteristics), it is possible to achieve short-time exposure, and as a result, a high-speed shutter function is exhibited and imaging blurring is greatly increased. The power consumption can be greatly reduced along with the improvement of the light emission efficiency.
[0036]
In this embodiment, the light transmission type filter 8b is used, but other types of optical components having wavelength selectivity such as a reflection type filter and a spectral prism may be used. Furthermore, in this embodiment, the timing means for detecting the timing at which the paper sheet is beaten based on the change in the reflected light from the paper sheet has been described. However, the present invention is not limited to this, and light transmitted through the paper sheet is not limited thereto. The measurement may be performed one by one, and the trigger signal S1 may be generated by determining that the paper sheet has been rolled when the transmitted light changes. More specifically, the light emitting surface of the light emitting diode 10 and the light receiving surface of the light receiving element 11 are arranged to face each other, and each time the sheet is rolled, a mechanism that allows the sheet to pass between these elements 10 and 11 is used. To do. Therefore, the timing at which the paper sheet is beaten is determined based on the difference between the transmitted light amount detected when the paper sheet passes between these elements 10 and 11 and the light amount detected when the paper sheet does not pass. . Further, a so-called photo interrupter formed by unitizing the elements 10 and 11 may be used.
[0037]
Further, in this embodiment, the sheet turning timing is optically detected by the elements 10 and 11, but a mechanical detection sensor for detecting the turning timing in the turning mechanism itself for turning the sheet. Alternatively, an electrical detection sensor may be provided, and the trigger signal S1 may be generated based on output signals from these detection sensors.
[0038]
Further, since the timing means described above sequentially detects the timing at which the paper sheet is rolled and causes the paper sheet to be read in synchronization with the detection timing, even if the cycle of rolling each paper sheet is changed, accurate paper sheet reading is performed. Enable. In other words, even when the sheet turning cycles shown in the timing chart of FIG. 2 (for example, Ti and Ti + 1 are different), accurate sheet reading is possible. It should be noted that it is not prohibited to have a device configuration in which the turning cycle is always kept constant by the turning mechanism.
[0039]
Next, a second embodiment will be described with reference to the drawings. Since the basic apparatus configuration is the same as that of the first embodiment, differences from the first embodiment will be mainly described with reference to FIG.
[0040]
The illumination light source 6 of the second embodiment is an illumination having a wavelength band in which the center wavelength is about 660 nm and the half-value width is in the range of about 600 nm to about 700 nm, as shown by the characteristic curve shown by the one-dot chain line R in FIG. A plurality of red light emitting diodes that uniformly irradiate light onto a paper sheet are arranged on the light emitting surface.
[0041]
Further, as shown in FIG. 6, the light transmission filter 8b is a short-wavelength removal type filter whose cutoff wavelength is set to about 600 nm. In FIG. 6, the characteristic indicated by the solid line indicates the actual transmission characteristic, and the characteristic indicated by the dotted line indicates the transmission characteristic normalized with the maximum transmission being 100%. However, here, instead of the red light-emitting diode, a green light-emitting diode 10 having the characteristic indicated by the characteristic curve G in FIG. 3 is used, and the light-receiving element is a spectroscope adapted to the characteristic curve G of the green light-emitting diode 10. A light receiving element 11 having characteristics is used. That is, if the same red light emitting diode as that in the first embodiment is used in this embodiment, the SN is reduced by being confused with the illumination for reading. Green light is applied. However, the green light emitting diode 10 is not limited to the case where the sheet turning timing can be reliably detected.
[0042]
The remaining components, that is, the insertion unit 2, the optical lens group 8b, the CCD solid-state imaging device 9, the drive circuits 12 and 15, the waveform shaping circuit 13, the timing circuit 14, the video process circuit 16, and the identification circuit 17, This is the same as in the first embodiment.
[0043]
Next, the operation of the second embodiment will be described. As described above, the drive circuits 12 and 15, the waveform shaping circuit 13, the timing circuit 14, the video process circuit 16, and the identification circuit 17 are the same as those in the first embodiment. The operation will be described based on this.
[0044]
First, when an operator bundles a plurality of paper sheets 4 and attaches them to the loading unit 2 and starts the reading process, the green light emitting diode 10 is continuously turned on, and then the turning mechanism starts to turn each paper sheet.
[0045]
The waveform shaping circuit 13 generates a binary logic trigger signal S1 each time a photoelectric conversion signal S0 indicating whether a sheet is rolled or not is output from the light receiving element 11.
[0046]
The timing circuit 14 supplies the illumination drive signal S2 to the drive circuit 15 in synchronization with the timing at which the trigger signal S1 is inverted from logic “L” to “H”, thereby turning on the illumination light source 6 for a predetermined period τ1. In this embodiment, τ1 = 200 μsec is set, and in this period τ1, the illumination light source 6 performs illumination of red light having a center wavelength of about 650 nm.
[0047]
Further, in synchronism with the trigger signal S1, a charge discharge signal S2 is supplied to the CCD individual imaging device 9, and the CCD individual imaging device 9 performs unnecessary accumulated charge in a very short time when the charge discharge signal S2 becomes logic "H". Is discharged to the outside. That is, since the pixel signal (charge) accumulated in the CCD individual imaging device 9 before starting illumination by the illumination light source 6 is not necessary for the original reading process, it is discharged in advance before starting the next reading process.
[0048]
Then, after the unnecessary charge discharging process is completed, the timing circuit 13 supplies the charge accumulation signal S4 to the CCD individual imaging device 9 in a predetermined period τ2, thereby imaging the surface of the paper sheet. Here, the period τ2 is set to an exposure period that is substantially equal to the period τ1 in which the light source 6 is turned on, but actually, it is set to an exposure period that is somewhat longer than that. Accordingly, the lighting period τ1 is a substantial exposure time, and the lighting time τ1 is set to 200 μsec as described above. Therefore, an extremely high-speed electronic shutter function is exhibited, and the paper sheet moves during turning. However, it is possible to reliably capture an image of a paper sheet without blurring.
[0049]
Further, as described above, since the light transmission type filter 8b transmits only a red light component having a predetermined wavelength, the CCD solid-state imaging device 9 captures only an image of this wavelength component in the reflected light from the paper sheet. Therefore, even if external light from the fluorescent lamp 100 or the like installed in the office or the like enters the input unit 2, wavelength components outside the transmission wavelength band of the light transmission filter 8b, that is, unnecessary noise components are removed. The As shown in FIG. 5, a general white fluorescent lamp has a wavelength component in the range of about 400 nm to about 800 nm. Therefore, the CCD solid-state imaging device 9 also receives light from the white fluorescent lamp. However, since only the wavelength component substantially equal to that of the illumination light source 6 is received, the influence of the indoor lighting installed in the office or the like can be removed as a result, and the noise component due to external light is removed. be able to.
[0050]
Next, when the exposure in the period τ2 is completed, a read drive signal S5 for reading the pixel charge from the timing circuit 13 to the CCD solid-state imaging device 9 is supplied, and the period in which the signal S5 is logic “H”. The pixel signal S6 ′ for each pixel stored in the storage unit is output to the video process circuit 16 in a so-called dot-sequential manner, and the video process circuit 16 performs the video signal S6 based on the pixel signal S6 ′ in real time. As shown in FIG. Further, the video process circuit 16 starts to input the pixel signal S6 ′ in synchronization with the time when the read drive signal S5 is inverted from logic “L” to “H”, and the video signal is based on the input pixel signal S6 ′. S6 is formed and transferred to the identification circuit 17.
[0051]
Then, after the identification circuit 17 extracts the feature of the paper sheet based on the video signal S6, it compares the reference data stored in advance with this feature data, thereby determining the authenticity of the paper sheet and the number of read sheets. Counting processing is performed, and further data S7 indicating the result of the true / false judgment and the count value is output. When the processing is completed for this authenticity determination or the like, the next paper sheet reading processing is started.
[0052]
As described above, according to this embodiment, light that is substantially equal to the wavelength component of the irradiation light of the illumination light source 6 among the reflected light from the paper sheet is selected by the light transmission type filter 8b, and the CCD solid-state imaging device 9 is used. Since the imaging is performed, the influence of the external light from the indoor lighting 100 installed in the office or the like is removed, and it is possible to take a picture in an optimal exposure state. A fake decision can now be made.
[0053]
Further, the wavelength component of the external light from the room illumination 100 has a wide wavelength band as shown in FIG. 5, while the wavelength component of the illumination light from the illumination light source 6 has a narrow wavelength as shown by a one-dot chain line R in FIG. Limited to bandwidth. Therefore, the light component transmitted through the light transmissive filter 8b is mainly composed of the light component of the illumination light, so that the CCD solid-state imaging device 9 can capture an image in an almost constant exposure environment. 17, it is possible to perform a true / false determination with high accuracy. In this embodiment, among the light intensities of the light image received by the CCD solid-state imaging device 9, the light intensity I2 of the light component due to the external light relative to the light intensity I1 of the light component due to the illumination light is relatively set to I2 / I1. = It was confirmed by experiment that it can be reduced to 1/20.
[0054]
In addition, since the illumination light source 6 is composed of a group of red light emitting diodes with good response characteristics (switching characteristics), it is possible to achieve short-time exposure, and as a result, a high-speed shutter function is exhibited and imaging blurring is greatly increased. The power consumption can be greatly reduced along with the improvement of the light emission efficiency.
[0055]
In this embodiment, as in the first embodiment, optical components having other types of wavelength selection characteristics such as a reflective filter and a prism may be used.
[0056]
In this embodiment, a long-wavelength selection filter that transmits light of a long-wavelength component is applied to remove external light, but conversely, of the reflected light image from the paper sheet, the illumination light You may make it remove the unnecessary component of external light using the short wavelength selection filter which selects the short wavelength component below the wavelength component of a specific wavelength band.
[0057]
Further, as the timing means for detecting the turning timing of the paper sheet, the transmitted light of the paper sheet or the turning timing of the turning mechanism itself may be detected as in the first embodiment. Further, a turning mechanism for turning each paper sheet at a constant cycle may be applied.
[0058]
【The invention's effect】
  As explained above, according to the present invention,In front of the imaging meansBy providing a wavelength selection filter, the external light component including the wavelength component of the illumination light from the reflected light from the paper sheet is removed and the image is taken. By removing the influence of external light from the illumination, it is possible to take an image in an optimal exposure state, and as a result, it is possible to perform true / false determination with high accuracy.
[0059]
Further, by providing the wavelength selection filter, the light component from the illumination light source is incident on the image pickup means as compared with the outside light, so that accurate image pickup can be performed under a constant exposure environment.
[0060]
In addition, by applying a CCD solid-state imaging device to the imaging means, a high-speed electronic shutter function can be exhibited, so that imaging blur can be significantly reduced.
[0061]
In addition, by applying a light emitting diode of a predetermined wavelength band to the illumination light source, it is possible to realize short-time exposure for demonstrating the electronic shutter function, and to greatly increase the power consumption accompanying the improvement of the light emitting efficiency of the light emitting diode. Reduction is possible.
[Brief description of the drawings]
FIG. 1 is a block diagram for explaining a configuration of an embodiment according to the present invention.
FIG. 2 is a timing chart for explaining the operation of the embodiment.
FIG. 3 is a characteristic diagram showing wavelength characteristics of illumination light of an illumination light source provided in the embodiment.
FIG. 4 is a characteristic diagram showing wavelength selection characteristics of a light transmission type filter provided in the first embodiment.
FIG. 5 is a characteristic diagram showing a wavelength band of a white fluorescent lamp.
FIG. 6 is a characteristic diagram showing wavelength selection characteristics of a light transmission type filter provided in the second embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 2 ... Input part, 4 ... Paper sheet, 6 ... Illumination light source, 8 ... Imaging optical system, 8a ... Optical lens system, 8b ... Light transmission type filter, 9 ... CCD solid-state imaging device, 10 ... Red light emitting diode, 11 ... Light reception Elements 12, 15, drive circuit 13, waveform shaping circuit 14, timing circuit 16, video process circuit 17, identification circuit
Attorney Yoshiki Hasegawa

Claims (2)

In a paper sheet reading apparatus that sequentially switches one or more paper sheets and sequentially reads them,
Timing means for detecting the timing at which each paper sheet to be read is switched;
An illumination light source according to the synchronization with the detection timing to illuminate the illumination light of a predetermined wavelength band, the light emitting diode for irradiating the illumination light to the paper sheet of said timing means,
A wavelength selection filter that selects a wavelength component of a specific wavelength band of the illumination light from the reflected light image from the paper sheet;
Wherein in synchronization with the detection timing of said timing means, anda imaging means for imaging the reflected light image incident through the wavelength selective filter,
The wavelength selection filter is disposed in front of the imaging unit so as to selectively pass a wavelength component of a specific wavelength band of the illumination light in the reflected light image from the paper sheet,
The paper image reading apparatus according to claim 1, wherein the image pickup means comprises a CCD solid-state image pickup device for picking up the reflected light image in a predetermined period after discharging unnecessary charges in synchronization with the detection timing of the timing means .   The wavelength selection filter is a bandpass filter that selects a wavelength component in a specific wavelength band of the illumination light from the reflected light image from the paper sheet, or a specific wavelength of the illumination light from the reflected light image from the paper sheet A long wavelength selection filter that selects a long wavelength component that is greater than or equal to a wavelength component of the band, or a short wavelength selection filter that selects a short wavelength component that is less than or equal to the wavelength component of the specific wavelength band of the illumination light from the reflected light image from the paper sheet The paper sheet reading device according to claim 1, wherein the paper sheet reading device is any one of the above.

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