JP2010225164A - Image reading apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image reading apparatus for reading a watermark image by disposing a light source to be inclined by only a predetermined angle with respect to a perpendicular face of an irradiation object, and by receiving scattered light generated by an effect that the light from the light source is scattered by undulation at a transmission portion of the irradiation object. <P>SOLUTION: The image reading apparatus includes: a conveyor means for conveying the irradiation object having a black watermark of a light transmission portion and a white watermark; a transmission type light source disposed at one face side of the irradiation object for irradiating the irradiation portion of the irradiation object with light inclined by only a predetermined angle with respect to the perpendicular face of the irradiation object; a rod lens array disposed in parallel with the perpendicular face of the irradiation object at the other face side of the irradiation object for converging the scattered transmitted light generated by an effect that the light irradiating the irradiation portion is scatter-reflected by the undulation of the black watermark and the white watermark of the irradiation object; a sensor for imaging the scattered transmitted light converged by the rod lens array, and outputting the imaged image at each line; and a signal processing unit for collating the image signal imaged by the sensor with black watermark image data of the irradiation object stored in advance. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image reading apparatus that reads a light transmission portion of an irradiated object such as a banknote.

  Conventionally, as this type of reading apparatus, for example, there is one described in Japanese Patent Application Laid-Open No. 2000-113269 (Patent Document 1). That is, in Patent Document 1, a watermark pattern such as a banknote is irradiated with light, the transmitted light is detected by an artificial retina chip, and the shape of a transmissive part (hereinafter also referred to as “watermark part”) or the like. A bill appraisal device is described in which presence / absence information is processed by a knowledge processing circuit to approve bills and the like. On the other hand, Japanese Patent Application Laid-Open No. 2003-87564 (Patent Document 2) describes an image reading apparatus using both a transmissive type and a reflective type. The image reading apparatus accommodates a light source for a transparent document in a document cover, detachably locks the document mat on the document cover, and attaches the document mat to the document cover when reading a reflected document, An image reading apparatus is described in which a document mat is removed from a document cover when a transparent document is read.

JP 2000-113269 A (FIG. 1) JP 2003-87564 A (paragraph 0024, FIG. 2)

  However, in the banknote appraisal device described in Patent Document 1, the watermark part such as a banknote is verified by transmitting so-called direct light from a light source to the watermark part such as a banknote and converting it into an electrical signal. The image of the watermark portion such as was read.

  In the image reading apparatus described in Patent Document 2, a so-called transmissive image reading apparatus (hereinafter also simply referred to as “transmission type”) and a reflection type image reading apparatus (hereinafter simply referred to as “reflection type”). In this case, in reading the image in the transmission part of the light by the transmission type, the image of the transmission part is read by so-called direct light.

According to the present invention, a light source is disposed on one surface side of an object to be irradiated and inclined at a predetermined angle with respect to a vertical surface of the object to be irradiated, and light from the light source is undulated in a transmission part of the object to be irradiated. An object of the present invention is to provide a novel image reading apparatus that receives the scattered light scattered by the laser beam to read the transmission part of the irradiated object.
Further, according to the present invention, a transmissive light source is disposed on one surface side of an object to be irradiated and inclined by a predetermined angle with respect to a vertical surface of the object to be irradiated, and light from the transmissive light source is irradiated The scattered light scattered by the undulations in the transmission part of the object is received and a reflective light source is arranged on the other surface side of the irradiated object, and the light from this reflective light source is reflected by the reflective part of the irradiated object It is an object of the present invention to provide a novel image reading apparatus that receives reflected light and reads a transmission part and a reflection part of an object to be irradiated.

  An image reading apparatus according to the invention of claim 1 is disposed on one surface side of the object to be irradiated, the conveying means for conveying the object to be irradiated having a black watermark and a white watermark which are light transmission parts, and the object to be irradiated. A transmissive light source that irradiates the irradiated portion of the irradiated object with light at a predetermined angle with respect to the vertical plane, and is arranged in parallel to the vertical plane of the irradiated object on the other surface side of the irradiated object, A rod lens array that converges the scattered transmitted light that is scattered and reflected by the undulation of the black watermark and the white watermark of the irradiated object, and the scattered transmitted light that is converged by the rod lens array. And a signal processing unit that collates an image signal formed by the sensor and an image signal formed by the sensor with a black watermark image data of an irradiated object stored in advance. It is.

  An image reading apparatus according to the invention of claim 2 is disposed on one surface side of the irradiated object, the conveying means for conveying the irradiated object having a black watermark and a white watermark which are light transmission portions, and the irradiated object. A transmissive light source that irradiates the irradiated portion of the irradiated object with light at a predetermined angle with respect to the vertical plane of the light, a light guide member that guides the light of the transmissive light source to the irradiating portion, and the other of the irradiated object A rod that is arranged in parallel to the vertical surface of the irradiated object on the surface side of the light and converges the scattered transmitted light that is scattered and reflected by the undulation of the black watermark and white watermark of the irradiated object by the light irradiated on the irradiation unit A lens array, a sensor that forms an image of the scattered transmitted light converged by the rod lens array and outputs it for each line, an image signal formed by the sensor, and a black watermark image data of the irradiated object stored in advance And a signal processing unit for matching It is an feature.

  According to a third aspect of the present invention, there is provided an image reading apparatus that conveys an irradiated object having a black watermark and a white watermark that are light transmitting portions, and extends in the main scanning direction of the irradiated object conveyed by the conveying means. A detecting means for detecting a transmission part of the irradiated object and one surface side of the irradiated object, and tilted by a predetermined angle with respect to the vertical surface of the irradiated object to the irradiated part of the irradiated object A transmissive light source for irradiating light while the transmission part of the irradiated object detected by the detecting means is conveyed by the conveying means, and a vertical surface of the irradiated object on the other surface side of the irradiated object A rod lens array that is arranged in parallel to each other and converges the scattered transmitted light that is scattered and reflected by the undulation of the black watermark and white watermark of the irradiated object, and is converged by the rod lens array. The line is formed by imaging the scattered transmitted light. A sensor for outputting to, is characterized in that the sensor has a signal processing section for collating the image data of the black watermark pre housed the irradiated object and the image signal obtained by imaging.

  According to a fourth aspect of the present invention, there is provided an image reading apparatus that conveys an irradiation object having a black watermark and a white watermark that are light transmission portions, and an irradiation object that is conveyed by the conveyance means in the main scanning direction. A detecting means for detecting a transmission part of the irradiated object and one surface side of the irradiated object, and tilted by a predetermined angle with respect to the vertical surface of the irradiated object to the irradiated part of the irradiated object A transmissive light source that emits light while a transmissive portion of the object detected by the detecting means is being conveyed by the conveying means, and a light guide member that guides the light from the transmissive light source to the irradiating unit The light is irradiated on the other surface side of the irradiated object in parallel with the vertical surface of the irradiated object, and the light irradiated to the irradiation unit is scattered and reflected by the undulation of the black watermark and the white watermark of the irradiated object. Rod lens array that converges transmitted light and this rod lens A sensor that forms an image of the scattered transmitted light converged by the ray and outputs it for each line, and a signal processing unit that collates the image signal formed by this sensor with the image data of the black watermark of the irradiated object stored in advance. It is characterized by comprising.

  According to a fifth aspect of the present invention, in the image reading device, the signal processing unit deletes data other than the black watermark image data from the image signal, and stores the black watermark image data of the irradiated object stored in advance. Are in any one of claims 1-4.

  An image reading apparatus according to a sixth aspect of the present invention is the image reading device according to the fifth aspect, wherein the signal processing section deletes the image signal having a predetermined value or less as other than the image data of the black watermark. .

  According to the present invention, one surface side of the irradiated object having the black watermark and the white watermark which is a light transmitting portion is inclined by a predetermined angle with respect to the vertical surface of the irradiated object. A transmissive light source for irradiating light is arranged in the irradiating unit, and the light transmitted from the transmissive light source to the irradiating unit receives scattered transmitted light that is scattered and reflected by the undulation of the black watermark and white watermark of the irradiated object. As a result, the watermark portion of the transparent portion of the irradiated object can be read and collated with the black watermark image data of the irradiated object stored in advance.

1 is a cross-sectional configuration diagram of an image reading apparatus according to Embodiment 1 of the present invention. It is a top view of the transparent body of the image reading apparatus which concerns on Embodiment 1 of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram of the image reading apparatus which concerns on Embodiment 1 of this invention, (a) is a top view, (b) is a side view. 1 is a plan view of an image reading apparatus including a conveying unit according to Embodiment 1 of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block configuration diagram of an image reading apparatus according to Embodiment 1 of the present invention, where (a) is an overall block configuration diagram, and (b) is a block configuration diagram of a verification circuit. It is a timing diagram of the photo sensor of the image reading apparatus according to the first embodiment of the present invention. FIG. 3 is a timing diagram of image output of the image reading apparatus according to the first embodiment of the present invention. It is explanatory drawing of the transmitted light and reflected light of the transmissive light source of the image reading apparatus which concerns on Embodiment 1 of this invention, (a) used the transparent sheet, (b) gave the undulation to the transparent sheet In the case, (c) is a diagram for explaining the ratio of transmitted light and reflected light by each material. It is a figure explaining the convergence state of the scattered light by watermark parts, such as a banknote. It is an image digital output figure of the image reading apparatus which concerns on Embodiment 1 of this invention. It is an image collation data diagram of the image reading apparatus according to the first embodiment of the present invention. It is a block block diagram of the collation circuit of the image reading apparatus which concerns on Embodiment 1 of this invention.

Embodiment 1 FIG.
(Constitution)
Embodiment 1 of the present invention will be described below with reference to FIG. FIG. 1 is a cross-sectional configuration diagram of an image reading apparatus according to the first embodiment. In FIG. 1, reference numeral 1 denotes an object to be irradiated (hereinafter simply referred to as “original” or “banknote”) such as banknotes, securities, or checks, and a translucent or transparent watermark portion (hereinafter referred to as a transmissive portion). And a reflective portion through which light is hardly transmitted.

  Reference numeral 2 denotes a contact image sensor (hereinafter simply referred to as “CIS”) disposed on one side of the document 1 (lower side in FIG. 1). Reference numeral 3 denotes a first light source (hereinafter referred to as a reflective light source) disposed on both sides of the CIS 2, which is disposed on one surface side of the document 1 and is an LED chip across the width direction (main scanning direction) of the document 1. Are linearly arranged in an array. Reference numeral 4 denotes a refractive light guide that guides light emitted from each reflection type light source 3 so as to be applied to the irradiating unit 5 of the document 1, and includes a light emitting unit 4 a. Here, with respect to the irradiating unit 5, the light from the reflective light source 3 is a linear portion in the main scanning direction in which the original 1 is irradiated on the conveying path of the original 1, and the reading portion of the original 1 being conveyed is means.

  Reference numeral 6 denotes a transparent body having a thickness of about 2.5 mm made of a transparent plastic material having a function of preventing foreign substances and the like from entering the CIS 2. The document 1 is conveyed so as to be guided outside the transparent body 6. . 7 is a rod lens array in which the light emitted from the reflective light source 3 is reflected on one surface side of the document 1 and converges the reflected light, and 8 is a light receiving unit that receives the reflected light converged by the rod lens array 7. Part (sensor), which is constituted by a sensor IC incorporating a plurality of photoelectric conversion parts and their drive circuits. Reference numeral 9 denotes a sensor substrate on which a plurality of light receiving portions (also referred to as sensors or sensor ICs) 8 are mounted, and reference numeral 10 denotes a substrate constituted by a printed wiring board or the like on which the reflection type light source 3 is mounted on both sides.

  11 includes a signal processing unit including a correction circuit that performs shading correction and all bit correction on the signal output of each pixel (bit) after the analog signal photoelectrically converted by the light receiving unit 8 is A / D converted, and the original 1 This is a signal processing IC (ASIC) that outputs image information from as an image signal. Reference numeral 12 denotes a connector supported on the back side of the substrate 10 for supplying power to a system signal (SCLK), a start signal (SI), a clock signal (CLK), and an input signal such as a power source for driving the CIS 2 and a light source. The control signal is input / output, and the image signal (SIG) or the like is output to the outside. 13 is a relay connector for transferring signals between the sensor substrate 9 and the substrate 10, 14 is an internal housing for housing and holding the rod lens array 7 and the sensor substrate 9, and 15 is a refractive light guide. 4 is an external housing for storing and holding the transmission body 6 and the substrate 10. The internal housing 14 is held by the relay connector 13, and the transmissive body 6 is fixed to the external housing 15 by providing a notch or the like. As described above, the reflection type is configured by the reflection type light source 3, the rod lens array 7, the light receiving unit 8, and the like.

  On the other hand, reference numeral 20 denotes a transmissive light source body that emits light over the main scanning direction of the document 1. In the transmissive light source body 20, reference numeral 21 denotes a second light source (hereinafter referred to as a transmissive light source) in which LED chips are linearly arranged in an array over the main scanning direction, and 22 denotes a transmissive light source. A trumpet type light guide that guides light emitted from the document 21 to the document 1, and has a light emitting part 22a. The light emitted from the light emitting unit 22 a is configured to irradiate the irradiation unit 5 in the conveyance path of the document 1. Further, the light emitted from the light emitting portion 22a is irradiated with an angle of about 45 degrees with respect to the optical axis of the rod lens array 7 orthogonal to the conveyance direction of the document 1.

  Reference numeral 23 denotes a transparent glass plate through which light is transmitted, reference numeral 24 denotes an LED substrate on which the LED chip of the transmissive light source 21 is mounted, and reference numeral 25 denotes power supported by the LED substrate 24 to drive the transmissive light source 21. 26 is a housing for storing and holding the trumpet light guide 22, the glass plate 23, and the LED substrate 24. Reference numeral 27 denotes an upper conveyance guide made of a plastic material having a thickness of 2.5 mm. As described above, the transmissive type includes the transmissive light source 21, the rod lens array 7, the light receiving unit 8, and the like. In the figure, the same reference numerals indicate the same or corresponding parts.

  FIG. 2 is a plan view of the transmission body 6, and 6 a is a groove of the transmission body 6 provided in the convergence region of the rod lens array 7. The groove has a constant width in the conveyance direction of the document 1 and is formed as a cavity from one end to the other end in the main scanning direction.

  3 is a configuration diagram of the image reading apparatus according to the first embodiment, FIG. 3a is a plan view thereof, and FIG. 3b is a side view thereof. In FIGS. 3 a and 3 b, 27 a is a recess of the upper conveyance guide 27 provided in the convergence region of the rod lens array 7. The recess 27a is wide in the conveyance direction of the document 1 and is integrally formed in a concave shape from one end to the other end in the main scanning direction. A stay 28 supports the upper conveyance guide 27 and the transmissive light source body 20. The upper conveyance guide 27 and the stay 28 are fixed by an elastic adhesive, and the transmissive light source body 20 and the stay 28 are screwed through a contact plate 29. Then, the document 1 is conveyed through the gap between the transmissive member 6 and the upper conveyance guide 27. This gap is approximately 0.3 mm to 1 mm depending on the position. The closer to the irradiation unit 5 in the conveyance direction, the more the deflection of the upper conveyance guide 27 and the transmission light source 21 occur, and the gap becomes narrower. This is to improve the reading accuracy by smoothing the document 1 even if the document 1 has wrinkles or bends. In the figure, the same reference numerals as those in FIG. 1 denote the same or corresponding parts.

  FIG. 4 is a plan configuration diagram including a conveying unit of the image reading apparatus according to the first embodiment. That is, reference numeral 30 denotes a conveyance roller, which includes a paper feed roller 30a, a paper discharge roller 30b, a document 1 take-out roller 30c, and a document 1 take-in roller 30d. The conveyance roller 30 conveys the document 1 by driving a motor (not shown) based on a predetermined conveyance signal. Reference numeral 31 denotes a cassette for storing the document 1, and includes a paper feed side cassette 31a and a paper discharge side cassette 31b. 32 is a cradle for fixing the CIS 2, 33 is a fixing means for fixing the detecting means as a photosensor, the transmissive light source body 20 and the upper transport guide 27 via the stay 28, and 34 is for placing the document 1. The document table to be placed.

Reference numeral 36 denotes a detecting means (hereinafter simply referred to as “photosensor”) constituted by a separation type photosensor having a light emitting element 36 a and a light receiving element 36 b, and extends from one end of the original 1 to the other end in the main scanning direction of the original 1. Exist. The photosensor 36 is provided with a connector 36 c, and the photosensor 36 is positioned and fixed by a fixing holder 33 through a stay 37. The photosensor 36 is provided with a predetermined distance (for example, L = 50 mm) away from the irradiation unit 5 in a direction opposite to the conveyance direction of the document 1, and the document 1 is disposed between the light emitting element 36a and the light receiving element 36b. It is comprised so that it may be conveyed. With respect to the photosensor 36, the light emitted from the light emitting element 36a is reflected by the reflection portion of the document 1 and does not reach the light receiving element 36b, but the transmission portion of the document 1 is the transmission portion. And reaches the light receiving element 36b. At this time, the photosensor 36 receives light by the light receiving element 36b until the transmission part of the document 1 finishes passing.

  Therefore, in FIG. 4, the photo sensor 36 is fixed to the stay 37. The document 1 placed on the upper side of the sheet feeding side cassette 31a is sequentially conveyed to the irradiation unit 5 in the reading area of the CIS 2 by the conveyance rollers 30c and 30a. A photo sensor 36 that detects a transparent portion including a black watermark and a white watermark of the document 1 in the transport path of the document 1 is installed at a predetermined distance L away from the irradiation unit 5 on the side opposite to the transport direction. ing. In FIG. 4, three photosensors 36 are provided at equal intervals in the main scanning direction of the document 1, but the transmissive portion of the document 1 starts from one end in the main scanning direction of the document 1 as shown in FIG. 4. If it is formed over the other end, the photosensor 36 may be composed of one. Moreover, the banknote 1 which passed the reading area | region is accommodated in the cassette 31b with the conveyance rollers 30b and 30d. Here, the transport rollers 30a and 30b are driven in synchronism so that the transport speed of the document 1 is transported at, for example, 250 mm / sec. In FIG. 4, the same reference numerals as those in FIGS. 1 and 3 denote the same or corresponding parts.

  The CIS 2, the transmissive light source body 20, the photo sensor 36, and the like are fixed to the main body of an image reading device (reading system) of a financial terminal device, for example.

(Light source on and off)
In the image reading apparatus according to the first embodiment, if the reflective light source 3 is turned on while the reflection portion of the document 1 is transported through the irradiation unit 5, the reflection from the reflection portion of the document 1 in the irradiation unit 5 is reflected. The reflected light is imaged on the light receiving unit 8 through the rod lens array 7. At this time, the transmissive light source 21 is turned off. On the other hand, while the transmissive part of the document 1 is transported through the irradiation unit 5, if the transmissive light source 21 is turned on, the transmitted light transmitted through the transmissive part of the document 1 is received through the rod lens array 7. The image is formed on the part 8. At this time, the reflective light source 21 is turned off. Here, the reflective light source 3 and the transmissive light source 21 are turned on and off in this way. However, even if the transmissive light source 21 is lit while the reflective light source 3 is lit, the transmissive light source 21 is turned on. Is reflected by the reflecting portion of the document 1 and hardly received by the light receiving unit 8 via the rod lens array 7, the reading of the reflecting portion of the document 1 is performed even when the transmissive light source 21 is turned on. Has little effect.

  On the other hand, if the reflective light source 3 is turned on while the transmissive light source 21 is lit, the light from the reflective light source 3 is transmitted through the transmissive portion of the document 1, but part of the light is from the document 1. There is a possibility that the light is reflected by the transmissive part and received by the light receiving unit 8, which may affect accurate reading in the transmissive part of the document 1. Therefore, in such a case, it is better to turn off the reflective light source 3 while the transmissive light source 21 is on.

(Light source on / off control)
5a and 5b are block configuration diagrams of the image reading apparatus according to the first embodiment. In FIG. 5 a, reference numeral 40 denotes a light source driving circuit for turning on and off the reflective light source 3 and the transmissive light source 21. A control unit (CPU) 41 controls the light source driving circuit 40. That is, the timing signal for first detecting the transmission portion of the document 1 is input to the CPU 41 by the photosensor 36. At this time, when the conveyance speed of the document 1 is constant, the transmission portion of the document 1 reaches the irradiation unit 5 after the time corresponding to the predetermined distance L between the photo sensor 36 and the irradiation unit 5, and therefore the timing thereof. Then, the light source drive circuit 40 is driven to turn on the transmissive light source 21 and turn off the reflective light source 3. Then, the CPU 41 controls the light source driving circuit 40 so that the transmissive light source 21 is continuously turned on and the reflective light source 3 is turned off only during the time when the transmissive part of the document 1 is detected by the photosensor 36.

  On the other hand, after the reading system signal (SCLK) is input to the CPU 41, while the photo sensor 36 does not detect the transmission part of the document 1, the CPU 41 passes the photo sensor 36 through the reflection part of the document 1. The light source drive circuit 40 is driven and controlled so that the reflective light source 3 is turned on and the transmissive light source 21 is turned off. In this way, the CPU 41 drives and controls the light source driving circuit 40 to control the turning on / off of the reflective light source 3 and the transmissive light source 21. Note that 42 is a variable amplifier that amplifies an analog signal (also called SO analog image output), 43 is an A / D (analog / digital) converter that converts the analog signal into a digital signal, 44 is a correction circuit, and 45 is a matching circuit. It is.

  FIG. 6 is a time chart showing the relationship between the output signal (FO) of the photo sensor 36 and the lighting signals of the reflective light source 3 and the transmissive light source 21 with respect to the time axis. Assume that the document 1 is conveyed at, for example, 250 mm / sec. When the document 1 in the photosensor 36 is a reflection portion, the output signal (FO) of the photosensor 36 is at a low level, so that the reflective light source 3 is turned on (ON) and the transmissive light source 21 is turned off (OFF). )is doing. However, when the document 1 in the photosensor 36 reaches the transmission part, the output signal (FO) of the photosensor 36 is at a high level. At this time, the output signal (FO) of the photosensor 36 is reflected within, for example, 200 ms from the time when the output signal of the photosensor 36 rises within a predetermined level range, that is, between Vth (L) and Vth (H). The mold light source 3 is turned off (OFF), and the transmission light source 21 is turned on (ON). Then, the output signal (FO) of the photosensor 36 continues only between Vth (L) and Vth (H). FIG. 7 shows temporal changes in image output (SO) between the reflective light source reading area and the transmissive light source reading area. Image output (SO) appears sequentially in synchronization with the start signal (SI), and by providing a blanking period between the line outputs, it is possible to change the reading time and the conveyance speed.

(Operation of block configuration)
Next, the overall block diagram shown in FIG. 5a will be described. First, when a 0.5 ms / Line start signal (SI) synchronized with the CIS2 clock signal (CLK) is input to the light receiving unit 8 based on the reading system signal (SCLK), the light receiving unit 8 determines the timing. A photoelectrically converted analog signal (SO) is output. The SO is amplified by the variable amplifier 42, is then analog-digital (A / D) converted by the A / D converter 43, and is input to the correction circuit 44 and the verification circuit 45. The correction circuit 44 performs shading correction including sample and hold, all-bit correction, and the like. The digital signal data obtained from the SO is corrected by reading digital data storing preset reference signal data from the RAM 1 area and calculating and processing the image information collected from the document 1 and the correction circuit 44. This is performed in order to equalize the photoelectric conversion output by the light receiving unit 8 in consideration of variations of individual elements in the reflective light source 3, the rod lens array 7, the light receiving unit 8 and the like constituting the CIS 2.

  Further, the configuration of the matching circuit 45 incorporated in the correction circuit 44 is shown in FIG. The collation circuit 45 reads out digital data corresponding to a predetermined image pattern (also referred to as an undulation pattern) from the RAM 2 with respect to the image signal in the transparent portion of the document 1 and collates it with the image data in the actually read transparent portion. Is what you do. That is, when the transmissive light source 21 is turned on and the image in the transmissive part of the document 1 is read, the transmissive part of the document 1 is read by turning off the reflective light source 3 housed in the CIS 2 as described above. However, the illuminance thus obtained is photoelectrically converted by the light receiving unit 8 to obtain an image output signal (SIG). Then, this image output signal (SIG) is compared with the image data of the transmissive portion stored in the RAM 2, and if they match, the match signal (A) is output to the outside.

Next, a transmission light source installed at an irradiation angle of 45 degrees with respect to the document 1 will be described with reference to FIG. Light incident on a completely smooth transparent film such as an OHP sheet generates reflected light and transmitted light on the sheet surface. Usually, the reflected light is 10% or less, and the transmitted direct light is 90% or more.
When a transmissive light source is used, the light source is generally installed facing the optical axis of a lens (such as a rod lens array). In the first embodiment, the angle is 45 degrees with respect to the optical axis of the lens. Since no direct light or reflected light is incident on the lens, the sensor installed in the direction opposite to the document surface side of the lens has almost zero output.

  Next, as shown in FIG. 8b, a portion of the scattered light is generated by providing irregularities in the OHP sheet. Further, the scattered light is separated into scattered reflected light and scattered transmitted light, and the scattered transmitted light is generated at about 5%.

  FIG. 8 c compares the ratios of reflected light, directly transmitted light, and scattered transmitted light using various materials having transparency. The generation of scattered light is negligible in the transparent film, whereas the white translucent film generates scattered transmitted light that is reflected and refracted by the reflective surface inside the film. Further, in the watermark portion of the bill that is translucent, scattered and transmitted light is generated in the same manner as the unevenness provided on the OHP sheet. This is because the watermark portion such as banknotes has undulations when producing a black watermark or a white watermark.

  FIG. 9 is an enlarged schematic diagram of the watermark portion of the banknote 1, and a part of the transmitted light scattered in the banknote undulation state enters the light receiving unit 8 through the lens 7.

  In the case of the banknote 1, the visible light and infrared light from the transmissive light source 21 are larger in the light passing through the watermark portion than the light passing through the portion other than the watermark portion. Therefore, the lower limit of the output by the transmission part of the document 1 is set, and the output larger than the set value output is taken out as one line of line information. This is illustrated as a waveform diagram drawn in FIG. 5a. In this way, an output larger than the set value output is collated for each line for the presence or absence of a similar portion of the data stored in the RAM 2. For example, in reading of CIS2 having a resolution of 8 dots / mm, average data of continuous 4 bits is compared with data stored in RAM2, and a plurality of locations are determined based on the envelope shape of digital data. This is sequentially performed for each line. When the coincidence signal (A) is generated over a plurality of lines, the authenticity of the document 1 is determined on the reading system side.

(Verification)
Next, the collation method will be further described with reference to FIGS. 5a and 5b. When a banknote (original) 1 having a watermark portion (transmission portion) is transported along its longitudinal direction, the size of the banknote 1 is usually 80 mm or less, so in CIS with a resolution specification of 8 dots / mm. , An effective reading area of 640 bits is provided. The analog signal image output (SO) is A / D converted into a digital output, subjected to shading correction by the correction circuit 44, and sent from the SIG to the reading system as a digital image output. The output of the correction circuit 44 is also sent to the collation circuit 45 in common, and the collation circuit 45 compares the watermark image arranged in the watermark portion with the watermark image data stored in the RAM 2 in advance for collation.

  FIG. 10a is a digital output diagram representing a digital output obtained by simply averaging image data from an A / D converted digital image output in units of 4 bits. Here, since the A / D converter 43 uses an 8-bit resolution, it is assumed that the higher the numerical value expressed in 256 digits, the higher the output. For convenience, the information is collectively shown for every 5 digits. As shown in FIG. 5b, the data for each line (l) input to the verification circuit 45 is first calculated, averaged, and stored in a register (shift register). In the first embodiment, the number of bits of the register is 160 bits. Next, since the image of the watermark portion is collated, in order to delete unnecessary data other than the watermark portion, data of 10 digits or less is deleted.

  Next, as shown in FIG. 10b, in order to specify the watermark image of the watermark portion, the minimum output of the watermark image is set (the reference output is −30 in the first embodiment), and this value is added to each output. . On the other hand, the RAM 2 stores in advance the image data of the black watermark portion shown in FIG. 11a and compares it with the data of the watermark portion sent for each line. For comparison, the image data stored in the bidirectional register is transferred bidirectionally and compared with the RAM2 data (1) using the reading period of the next line. The reason why the reference output is set to −30 is to adjust the minimum output of the black watermark portion to a value larger than zero. When the light amount of the transmissive light source 21 is large like infrared light, the absolute value is further increased. This is because when the light quantity of the transmissive light source 21 is small, such as visible light, the absolute value is reduced to adjust. Further, this reference output may be automatically adjusted by the light receiving element for monitoring incorporated in the CIS 2 for the light quantity of the transmissive light source 21.

  Further, as shown in FIGS. 11b and 12, the RAM2 data stores a value that is different from the reference value of the RAM2 by ± 5 digits for each line (l) as the reference addition data and the reference subtraction data. Thus, by comparing with the digital output value of each image signal (SO), collation with high accuracy and few errors becomes possible.

  Also, as shown in FIG. 5b or FIG. 12, the corresponding CIS2 pixel position is specified from the number of shifts (transfers) of a bidirectional register having a cell of 160 bits or more, so the data at the specific pixel position is shifted in the next line. Transfer to register, latch (LA), compare with RAM2 data (2) and verify. At this time, the coincidence output (A) may be sent to the reading system. Similarly, the image data in the line is compared with the RAM2 data (3), and the coincidence output is used for simple collation. Is possible.

  In the above description, the image output from the image signal (SO) is the 4-bit averaged output because the watermark region image is regarded as a relatively coarse image. In addition, the averaged output is taken into account the contamination of the watermark area. That is, the image of the watermark area is read and determined with a resolution of 2 bits / mm. Therefore, when determining with higher density, it is possible to read an image with higher accuracy by applying CIS having a resolution of 12 dots / mm. The watermark part includes a black watermark (thick and thick watermark) and a white watermark (thin part). In the first embodiment, the transmissive light source 21 is arranged with respect to the optical axis of the rod lens array 7. As described above, the undulations of the black watermark portion and the white watermark portion are read as image data.

  Note that the area of the light receiving unit 8 without the banknote 1 is included in the area other than the watermark area since the output of the image signal (SO) is almost zero because the transmitted light tilts the transmissive light source 21. The tilt angle of the transmissive light source 21 is set to 45 degrees with respect to the optical axis of the rod lens array 7 (perpendicular to the conveying direction of the banknote 1 and the like). When the tilt angle is 60 degrees or more, the light from the transmissive light source 21 is also totally reflected and diverged from the scattered light, and the read output is lowered. Further, when the tilt angle is 30 degrees or less, the transmitted light is directly incident on the rod lens array 7 and the read output is increased. However, since the directly transmitted light is unnecessary light, the authenticity determination accuracy is lowered.

  DESCRIPTION OF SYMBOLS 1 Object to be irradiated (banknote), 2 Contact image sensor (CIS), 3 First light source (reflective light source), 4 Light guide (refractive light guide), 4a Light emission part, 5 Irradiation part, 6 Transmission Body, 7 lens (rod lens array), 8 light receiving unit (sensor), 9 sensor substrate, 10 substrate, 11 signal processing IC (ASIC), 12 connector, 13 relay connector, 14 internal housing, 15 external housing, 20 Transmissive light source, 21 second light source (transmissive light source), 22 light guide (trumpet light guide), 22a light emitting part, 23 glass plate, 24 LED substrate, 25 connector, 26 housing, 27 upper part Conveyance guide, 28 stay, 30 Conveyance roller, 31 Cassette, 32 Receiving base, 33 Fixed holder, 34 Document table, 36 Detection means (Photo sensor) ), 36a light-emitting side, 36b light receiving side, 36c connector 37 stay, 40 a light source drive circuit, 41 a control unit (CPU), 42 an amplifier (variable amplifier), 43 A / D converter, 44 correcting circuit, 45 matching circuits.

Claims (6)

  A conveying means for conveying an object to be irradiated having a black watermark and a white watermark as a light transmitting portion, and disposed on one surface side of the object to be irradiated, and inclined by a predetermined angle with respect to the vertical surface of the object to be irradiated. A transmissive light source for irradiating light to the irradiated portion of the irradiated object, and the other surface side of the irradiated object arranged in parallel to the vertical surface of the irradiated object, and the light irradiated to the irradiated portion is irradiated A rod lens array for converging the scattered transmitted light scattered and reflected by the undulations of the black watermark and the white watermark, and a sensor for imaging the scattered transmitted light converged by the rod lens array and outputting it for each line, An image reading apparatus comprising: a signal processing unit that collates an image signal formed by a sensor with a black watermark image data of an irradiation object stored in advance.   A conveying means for conveying an object to be irradiated having a black watermark and a white watermark as a light transmitting portion, and disposed on one surface side of the object to be irradiated, and inclined by a predetermined angle with respect to the vertical surface of the object to be irradiated. A transmissive light source that irradiates light to the irradiated portion of the irradiated object, a light guide member that guides the light of the transmissive light source to the irradiated portion, and a vertical surface of the irradiated object on the other surface side of the irradiated object The rod lens array for converging the scattered transmitted light scattered and reflected by the undulations of the black watermark and the white watermark of the irradiated object is converged by the rod lens array. An image provided with a sensor that forms an image of scattered transmitted light and outputs it for each line, and a signal processing unit that collates an image signal formed by the sensor with image data of a black watermark of an irradiated object stored in advance. Reader.   A conveying means for conveying an object having a black watermark and a white watermark, which are light transmission parts, and a main part of the irradiation object conveyed by the conveying means extend in the main scanning direction to detect a transmission part of the irradiation object. The detection means is disposed on one surface side of the object to be irradiated, and is inclined at a predetermined angle with respect to the vertical surface of the object to be irradiated. While the transmissive part is being transported by the transport means, the transmissive light source for irradiating light and the other surface side of the object to be irradiated are arranged in parallel to the vertical surface of the object to be irradiated and irradiated to the irradiation unit. A rod lens array that converges the scattered transmitted light that is scattered and reflected by the undulations of the black watermark and white watermark of the irradiated object, and forms an image of the scattered transmitted light converged by the rod lens array for each line. This sensor is connected to the output sensor. Image reading apparatus and a signal processing section for collating the image data of the black watermark was irradiated object in advance stored with the image signal.   A conveying means for conveying an object having a black watermark and a white watermark, which are light transmission parts, and a main part of the irradiation object conveyed by the conveying means extend in the main scanning direction to detect a transmission part of the irradiation object. The detection means is disposed on one surface side of the object to be irradiated, and is inclined at a predetermined angle with respect to the vertical surface of the object to be irradiated. While the transmissive part is being transported by the transport means, a transmissive light source that irradiates light, a light guide member that guides the light of the transmissive light source to the irradiating unit, and the other surface side of the object to be irradiated A rod lens array that is arranged in parallel to a vertical plane of an object, and that converges the scattered transmitted light that is scattered and reflected by the undulations of the black watermark and white watermark of the irradiated object, and the rod Combines scattered transmitted light converged by the lens array And a sensor for outputting for each line, the image reading apparatus and a signal processing section for collating the image data of the black watermark irradiated object that this sensor has been previously stored with the image signal imaged.   5. The signal processing unit according to claim 1, wherein data other than the black watermark image data is deleted from the image signal and collated with the black watermark image data of the irradiated object stored in advance. The image reading apparatus described.   The image reading device according to claim 5, wherein the signal processing unit deletes the image signal having a predetermined value or less as data other than the black watermark image data.

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