JP5752549B2 - Optical reader and paper sheet processing apparatus - Google Patents

Description

  Embodiments described herein relate generally to an optical reader and a paper sheet processing apparatus.

  Among authenticity items included in banknotes, forging a watermark image is difficult because it requires technology related to paper manufacturing technology, and it can be easily guessed that it is not easy. Accordingly, when a watermark is drawn by drawing a pattern in white or light color on the surface of the paper, there is a possibility that counterfeit tickets that produce the effect that the watermark image appears to be distributed. Various techniques have been proposed for inspecting these counterfeit tickets. These are configured to determine authenticity by acquiring and comparing the transmitted light image and reflected light image of the watermark image portion of the banknote, and comparing with the registered information.

  Considering miniaturization of equipment and cost reduction, it is composed of one light receiving sensor and multiple lighting devices (reflection and transmission conditions), and the reflection from banknotes while switching the illumination in time division when moving banknotes. Many mechanisms for acquiring light and transmitted light information have been proposed.

  The point of these inspection devices is that the genuine watermark image is a transmitted light image and has a light and shade change, but the outline of the watermark pattern etc. can hardly be confirmed with reflected light. The outline of the pattern can be confirmed with light. Therefore, it has been proposed to determine authenticity by comparing the characteristics of the watermark image portion of the transmitted light image and the reflected light image with the genuine characteristics.

  On the other hand, in the case of a counterfeit ticket in which a watermark image is created by squeezing it into the paper to be used, a function to determine authenticity from the transmitted light acquired image is mechanically provided so that the visual information obtained by humans is processed by the brain There are also examples. In this technique, discrimination processing is performed based on data obtained by integrating a transmitted light image of a watermark image in a fine area.

However, the prior art described above has the following problems.
(1) Number of inspection devices that can be installed in banknote processing equipment and issues related to speedup
In banknote processing equipment, it is necessary to distinguish between banknotes that can be redistributed while discriminating the degree and type of banknotes, and to distinguish between genuine and counterfeit banknotes. . According to each inspection purpose, a plurality of different functional units are arranged on the transport path for the inspection device to improve the overall authenticity discrimination performance.

  However, the size of the machine is determined according to the installation conditions and processing capacity of the product, and the number of inspection apparatus units that can be mounted is limited. Various security elements are included in banknotes in various countries. At the same time, many counterfeit tickets are in circulation, and high authenticity discrimination performance that can eliminate them is required. Therefore, the limitation of the number of units that can be mounted on the machine becomes a problem of performance realization.

  As a method for solving this problem, as described above, a light source that outputs illumination light of different wavelengths is mounted in the same unit so that it can illuminate banknotes, and a configuration with one light receiving sensor is prepared. The device is designed to acquire images with different illumination conditions by switching illumination light in a time division manner when the banknote passes. For example, there is a method of acquiring various pieces of medium information with different units of image information such as visible light and infrared light, reflected light and transmitted light.

  However, in this time-division exposure control method, since the number of divisions such as two divisions and three divisions is provided while the banknote is moving, the information of the acquired images is different, and the synchronization of the medium information cannot be ensured. In addition, when banknotes move at a high speed because of time division, there is a problem that the speed cannot be easily increased because of limitations on the amount of light that can be acquired and limitations on sensor driving time.

(2) Relationship between transport position variation and watermark inspection field of view
A banknote processing apparatus or the like has a mechanism for taking out banknotes one by one and passing the detection unit while moving the banknotes by nipping and conveying means such as a belt. In these devices, it is difficult to always pass banknotes at the same position, and there is a certain variation between the same aircraft and different aircraft. Specifically, a “slide” in which the position is shifted in the direction orthogonal to the conveyance direction due to the mechanism of the banknote to be detected or “skew” that rotates from the center of the banknote occurs.

  These machine-processed variations in the position of these banknotes to be transported must be allowed to be recognized and processed within a certain range. This tolerance is often different from product to product. This is because the conditions differ depending on the banknote transport speed, the ability of the mechanism downstream of the transport path, and the like. As an inspection apparatus, it is desirable in terms of the balance of the apparatus and the processing capability that it is possible to allow variation within the allowable range of the mechanism and maintain the detection performance.

  On the other hand, when viewed from the inspection device, the position to be inspected is different for each banknote passing through, and the conditions are not constant. In particular, when the watermark image to be inspected is a narrow part of the banknote and is arranged at the end of the banknote in the longitudinal direction, it is most affected. When inspecting a watermark image of a banknote, if a print image area other than the watermark image is mixed in the detection area, the effect of the print image portion having a low light transmittance is greater than that of a watermark image having a high light transmittance and is detected. The feature value varies greatly. As a result, there is a high possibility that a normal banknote is erroneously determined as a fake by determining the authenticity of the watermark image.

  Conventionally, in such a case, the influence has been reduced by setting the inspection target area to be narrow in consideration of the position fluctuation of the banknote. As described above, there is a problem that the inspection range of the banknote is narrowed as the range in which the deviation of the banknote transport position is allowed is widened.

  In addition, by using a neural network for the data obtained by dividing the inner surface of the banknote into fine integration areas, the connection relationship of the individual data that make up the pattern is captured, and the effect of banknote misalignment is removed. Technology has also been proposed, but fine brightness distribution is removed at the integration stage, and performance cannot be expected with delicate counterfeit tickets, and the surrounding printed image part is mixed in the detection range due to misalignment of banknotes As a result, there is a problem in that the ability to specify the watermark image position in the banknote affects the performance.

JP 2002-74449 A JP-A-6-203244 JP 2006-155341 A JP 2000-307819 A JP 2003-77025 A

  The problem to be solved by the present invention is to provide an optical reading apparatus and a paper sheet processing apparatus capable of detecting a watermark image of paper sheets and detecting shapes and defects on the same stage.

  The optical reading apparatus according to the embodiment includes a first light source that irradiates light having a first wavelength on one surface of a transported paper sheet, and one surface of the transported paper sheet. A second light source for irradiating light having a second wavelength at the same position as the light irradiation by the first light source, and the light from the first light source provided on the other surface side of the conveyed paper sheet A first light receiving means for receiving light having a first wavelength transmitted through the paper sheet by irradiation and converting it into an electrical signal; and provided on the other surface side of the transported paper sheet, And second light receiving means for receiving light having a second wavelength transmitted through the paper sheet by light irradiation of the two light sources and converting the light into an electric signal.

1 is a side view schematically showing an optical system portion of a shape / watermark detection device to which an optical reading device according to an embodiment is applied. 1 is a front view schematically showing an optical system portion of a shape / watermark detection device to which an optical reading device according to an embodiment is applied. The schematic diagram which shows an example of the banknote which concerns on embodiment. 1 is a block diagram schematically showing a configuration of a shape / watermark detection device to which an optical reading device according to an embodiment is applied. The schematic diagram explaining the process of the projection image process part which concerns on embodiment. The schematic diagram explaining the process of the projection image process part which concerns on embodiment. The schematic diagram explaining the process of the projection image process part which concerns on embodiment. The schematic diagram explaining the process of the projection image process part which concerns on embodiment. The schematic diagram explaining the process of the projection image process part which concerns on embodiment. The schematic diagram explaining the process of the transparent image correction process part which concerns on embodiment. The schematic diagram explaining the process of the transparent image correction process part which concerns on embodiment. The schematic diagram explaining the test object position fluctuation | variation at the time of the conveyance position dispersion | variation of the banknote which concerns on embodiment. The front view which shows typically the optical system part of the shape and watermark detection apparatus with which the optical reader which concerns on other embodiment is applied. The front view which shows typically the optical system part of the shape and watermark detection apparatus with which the optical reader which concerns on other embodiment is applied. The side view which shows typically the optical system part of the shape and watermark detection apparatus with which the optical reader which concerns on other embodiment is applied. The side view which shows typically the optical system part of the shape and watermark detection apparatus with which the optical reader which concerns on other embodiment is applied. FIG. 3 is a perspective view schematically showing an appearance of a paper sheet processing apparatus using a shape / watermark detection apparatus to which the optical reading apparatus according to the embodiment is applied. The block diagram which shows typically the internal structure of the paper sheet processing apparatus using the shape and watermark detection apparatus to which the optical reader which concerns on embodiment is applied. 1 is a block diagram schematically showing the configuration of a control system of a paper sheet processing apparatus using a shape / watermark detection apparatus to which an optical reading apparatus according to an embodiment is applied.

Hereinafter, embodiments will be described with reference to the drawings.
First, a paper sheet processing apparatus using a shape / watermark detection apparatus to which the optical reading apparatus according to the present embodiment is applied will be described.

  17 and 18 schematically show the configuration of a paper sheet processing apparatus using a shape / watermark detection apparatus to which the optical reading apparatus according to this embodiment is applied. This paper sheet processing apparatus 111, for example, inspects banknotes (hereinafter also referred to as paper sheets) sent from each branch of a plurality of banks, and binds only reusable banknotes and recycles them. It is for use.

  17 and 18, the paper sheet processing apparatus 111 has a supply unit 112 that sets a plurality of stacked banknotes at one end thereof. On the upper part of the supply unit 112, a take-out unit 113 is provided for taking out banknotes set in the supply unit 112 one by one from the upper end in the stacking direction. The take-out unit 113 has a suction roller 114 that rotates while being brought into contact with the uppermost bank note and generating a negative pressure. For example, the suction roller 114 functions to take out one banknote each time it rotates, and operates to take out banknotes at a constant pitch.

  On the downstream side of the take-out portion 113, a conveyance path 115 is extended as a conveyance means for conveying the banknotes taken out by the suction roller 114. A conveyance belt 115 and a drive pulley (not shown) are disposed in the conveyance path 115, and the banknotes are conveyed at a constant speed by running the conveyance belt by a drive motor (not shown).

  On the conveyance path 115 extending from the take-out unit 113, an inspection unit that detects optical and magnetic characteristic information of the banknote being conveyed and inspects the type, defacement loss, front and back, authenticity, etc. of the banknote. 116 is provided. The inspection unit 116 includes two image reading devices 117 and 118 that are arranged on both sides of the conveyance path 115 and read images on both sides of the banknotes to be conveyed. The image readers 117 and 118 have, for example, a CCD camera as an imaging unit, and read a pattern image on the surface of a banknote from the captured image.

  In addition, the inspection unit 116 includes a thickness inspection unit 119 that inspects the thickness of the banknotes conveyed along the conveyance path 115. The thickness inspection unit 119 is used to detect the removal of two banknotes.

  Further, the inspection unit 116 includes a shape / watermark detection device 135 that detects the shape of a banknote to be conveyed, a watermark image, and the like. Details of the shape / watermark detection device 135 will be described later.

  In addition, the inspection unit 116 also includes at least one or more magnetic sensors that detect magnetic characteristic information of banknotes.

  For example, six gates 120 to 125 are sequentially arranged on the conveyance path 115 on the downstream side of the inspection unit 116. The gates 120 to 125 are switched according to control by a control unit (not shown) based on the inspection result in the inspection unit 116, and guide the banknote to a predetermined processing unit.

  A gate 120 disposed immediately after the inspection unit 116 is provided at a position where the conveyance path 115 branches to the exclusion conveyance path 126, and is an exclusion ticket that is detected to be not a regular banknote via the inspection unit 116, Further, the inspection unit 116 is switched so as to guide the inspection impossible ticket that could not be inspected to the exclusion conveyance path 126.

  At the end of the reject conveyance path 126, the take-out order of the removal ticket and the non-inspectable ticket is kept in the posture taken out by the take-out unit 113, that is, without turning the front and back sides (in fact, rotated 360 °). An exclusion stacking unit (exclusion unit) 127 that stacks without change is provided.

  In addition to this, the exclusion stacking unit 127 collects, for example, a non-inspectable ticket in which banknotes are duplicated and a fake ticket that is determined not to be a regular banknote.

  Further, at positions branched by the gates 121 to 124 provided along the conveyance path 115 on the downstream side of the gate 120, first to fourth stacking / bundling sections (stacking sections) 128 to 131 (hereinafter, referred to as “the following sections”). In some cases, the collecting / binding unit 132 may be referred to as a collective name. In the stacking / binding unit 132, only the reusable genuine bills out of the regular banknotes other than the rejected ticket guided through the gate 120 are collected and bound.

  For example, the first and second stacking / binding portions 128 and 129 are stacked by bundling 100 correct bills with the surface up, and the third and fourth stacking / binding portions 130 and 131 are stacked. , 100 genuine tickets with the back side up are collected and bundled. Specifically, after collecting 100 sheets of correct bills in the stacking / binding unit 128 and then binding the 100 correct tickets, the other 100 correct tickets are stacked in the other stacking / binding unit 129. Accumulate. The correct bills bundled in the stacking / binding unit 132 in this manner are discharged out of the machine by a conveyor (not shown) and are reused.

  The bank branch other than the rejected ticket guided via the gate 120 is not accumulated in the stacking / binding unit 132 at a position branched from the conveyance path 115 by the gate 125 disposed on the most downstream side. A cutting section 133 is provided for storing a banknote, that is, a regular banknote, which is judged to be non-reusable due to reasons such as loss of pollution, and is made invalid. Note that when the non-slip sheet cutting mode is not selected, the non-slip sheet is not conveyed to the cutting unit 133 but is stacked on the stacker 134 for stacking non-slip tickets.

  Further, the paper sheet processing apparatus 111 has an operation unit 136 that is operated by an operator on the supply unit 112 side. The operation unit 136 is provided with an operation / display panel (display unit) 137 for receiving various operation inputs by the operator and displaying various operation guidance for the operator. The operation / display panel 137 includes a touch panel that detects an input of the button when the operator touches the displayed button. In addition, in the vicinity of the operation / display panel 137, there are a door 138 having a handle for opening and closing the banknote slot of the supply unit 112, an outlet 139 for taking out the banknotes accumulated in the exclusion stacking unit 127, an operator A keyboard 140 or the like operated by is provided.

  FIG. 19 schematically shows the configuration of the control system of the paper sheet processing apparatus 111 configured as described above.

  In FIG. 19, the main control unit 151 is responsible for overall control, to which the inspection unit 116, operation / display panel 137, and keyboard 140 are connected, respectively, the conveyance control unit 152, and stacking / binding. Control units 153 are connected to each other.

  The main control unit 151 controls the conveyance control unit 152 and the stacking / binding control unit 153 based on instructions from the operation / display panel 137, inspection results of the inspection unit 116, and the like.

  The inspection unit 116 processes the image reading devices 117 and 118, the thickness inspection unit 119, the shape / watermark detection device 135, other banknote sensors (such as a magnetic sensor) 154, and data from these. It is composed of a CPU (Central Processing Unit) 155 that detects optical and magnetic characteristic information to determine the type of banknote, fouling loss, front / back, authenticity, and the like.

  The transport control unit 152 controls the take-out unit 113, the transport path 115, the exclusion transport path 126, and the gates 120 to 125 based on the control of the main control unit 151, thereby performing banknote take-out and transport control.

  The stacking / binding controller 153 controls stacking / binding of banknotes by controlling the reject stacking unit 127 and the stacking / binding units 128 to 131 based on the control of the main control unit 151.

Hereinafter, the operation of the paper sheet processing apparatus 111 configured as described above will be briefly described.
First, a set of banknotes is set in the supply unit 112 by an operator's manual work. In this case, the operator opens the door 138 and sets the banknote in the supply unit 112. Thereafter, when the take-out unit 113 is driven, banknotes are taken out one by one from the top end onto the transport path 115. The banknotes taken out on the conveyance path 115 pass through the inspection unit 116 and are inspected.

  At this time, for example, when a plurality of banknotes are taken out by the takeout unit 113, images on the surface of the banknotes at both ends in the stacking direction are read by the image reading devices 117 and 118, respectively. As a matter of course, when only one bank note is normally taken out, the front and back images of the bank note are respectively read.

  The image read from the bank note in this way is temporarily stored in a memory (not shown) in the inspection unit 116 and displayed to the operator via the operation / display panel 137 as necessary. In the present embodiment, among the banknotes taken out by the takeout unit 113, only the images of banknotes accumulated in the exclusion stacking unit 127 are stored in the memory. The image stored in the memory can be switched and displayed by a predetermined operation on the operation / display panel 137.

  The inspection unit 116 determines whether the banknote is a legitimate banknote based on the image read by the image reading devices 117 and 118, the inspection result of the thickness inspection unit 119, the detection result of the shape / watermark detection device 135, and the like. Determine whether or not. As a result of the determination, if it is a regular bank note, it is determined whether or not the bank note is a reusable genuine note.

  As a result of this determination, if the bank note is a reusable genuine note, the gate 120 is switched to the direction of the conveyance path 115 toward the stacking / binding unit 132. Then, any one of the gates 121 to 124 is switched in the direction of the stacking / binding unit 132, and the correct bill guided through the gate 120 is stacked on any of the stacking / binding unit 132.

  In the present embodiment, for example, the first and second stacking / bundling units 128 are connected to a correct ticket whose front pattern is detected by one of the image reading devices 117, that is, a correct ticket conveyed with its surface facing up. , 129, and a correct ticket whose front pattern is detected by the other image reading device 118, that is, a correct ticket conveyed with the back side up, is accumulated in the third and fourth stacks. It is made to accumulate | store in any one of the binding parts 130 and 131. FIG.

  In this way, the front and back of the regular ticket are prepared. For example, when the first stacking / bundling unit 128 stacks the correct bills on the surface, and when the first stacking / binding unit 128 reaches 100 sheets, the 100 correct bills are bound. At the same time, the collection of the correct bills to the second stacking / binding unit 129 is started, and 100 sheets are alternately stacked and bound to the two stacking / binding units.

  If the banknote is a non-reusable banknote as a result of the determination, the gate 125 is switched, the banknote being transported is guided to the cutting unit 133, and the banknote is cut and expired. . It should be noted that the number of correct and accumulated bills and the number of non-performing bills that have been cut and expired are counted by the main control unit 151 and added up.

  As a result of the determination, if the bank note is not a regular bank note, the gate 120 is switched and the conveyance path 115 is connected to the exclusion conveyance path 126. Then, the inspection unit 116 determines whether or not the processing target medium is another medium. As a result of this determination, if it is determined that the target medium is not another medium, that is, it is determined from any of the images read by the two image reading devices 117 and 118 that the target medium is not another medium. It is determined that the processed medium is not a legitimate bank note, for example, a counterfeited rejected ticket, or it is determined that two or more banknotes have been duplicated, and the processed medium guided to the excluded transport path 126 The processing medium is collected as it is in the exclusion stacking unit 127.

  As a result of the determination, if the target medium is another medium, it is determined that the target medium is a foreign substance, for example, and the transport of the target medium is stopped and stopped on the removal transport path 126. In this way, the medium to be processed stopped on the removal conveyance path 126 is taken out and confirmed by the operator, and is processed manually.

Next, the shape / watermark detection apparatus 135 will be described in detail.
1 and 2 schematically show the configuration of the optical system portion of the shape / watermark detection apparatus 135. FIG. 1 and 2, a banknote (paper sheet) 11 has a watermark image P for preventing forgery and a printed image (not shown) as shown in FIG. It is assumed that the sheet is sandwiched by (corresponding to the transport path 115) and transported in the direction of the arrow a.

  On one surface side of the banknote 11 being conveyed, an illumination unit 14 irradiates infrared light as light having the first wavelength and visible light as light having the second wavelength on one surface of the banknote 11. Is provided.

  The illuminating unit 14 includes, for example, a plurality of LED chips (light-emitting elements) 15 arranged in a straight line at regular intervals in a direction orthogonal to the conveyance direction a of the banknotes 11, and an LED chip LR that emits infrared light. By arranging every other LED chip LW that emits visible light, mixed illumination light in which infrared light and visible light are mixed is realized.

  An illumination diffusion plate 16 is disposed between the illumination unit 14 and the banknote 11 to be conveyed. As a result, the effect of spreading the illumination light in an area where no light source exists between the bright spots of the LED chips that are point light sources can be obtained, and a linear illumination area can be secured.

  As the illumination diffusion plate 16, a material that diffuses light, such as milky white glass or a white film, is used. For example, a lens diffuser plate (LSD (Light Shaping Diffuser)) that can control the diffusibility with good transmission efficiency can be used.

  On the other side of the banknote 11 being conveyed, a light receiving portion 17 is provided for receiving infrared light and visible light transmitted through the banknote 11 and converting them into electrical signals. The light receiving unit 17 includes an image forming unit 18 such as a lens for connecting an optical image, and a first light receiving element 19 and a second light receiving element 20 such as a line image sensor. These two light receiving units 19 and 20 are separated into two wavelength lights by a dichroic mirror 21 provided in the light receiving optical path so as to receive light having different wavelengths.

  That is, in order to receive the transmitted light of the banknote 11 by light irradiation by the illuminating unit 14 by a linear optical axis, the first scanning is performed in a line shape such as a CCD line image sensor on the opposite side of the conveying path from the illuminating unit 14. A first light receiving element 19 and a second light receiving element 20 are provided. The two light receiving units 19 and 20 reflect the infrared light by the dichroic mirror 21 to be connected to the first light receiving element 19 in order to limit the light receiving wavelength in accordance with the two wavelength lights of the illumination unit 14, and the dichroic mirror 21. Visible light that passes through the second light-receiving element 20 is imaged. As described above, the light receiving unit 17 is also separated by the two wavelength lights in accordance with the two different wavelength lights of the illuminating unit 14 and forms an image of the same portion at the same time.

  In addition, the wavelength and arrangement | positioning received can also be changed by changing the dichroic mirror 21 into the type which reflects visible light and permeate | transmits infrared light.

  With such a configuration, a transmitted light image of the same portion of the banknote 11 can be acquired as an image captured at two different wavelengths. In the present embodiment, the watermark image P incorporated as a security element for authenticity in the bank note 11 is inspected by a change in the density of transmitted infrared light, and the projected shape by the transmitted visible light is used to determine the outer shape of the bank note 11. Inspect the position of the end face, damage and defects.

  In these two inspections, the transmitted light amount of the banknote 11 is inspected, but there is a great difference in the transmitted light level. A watermark image or the like attenuates the transmitted light amount to about 1/10 or less of the illumination light amount due to transmission and absorption of diffused light through the paper. It is necessary to extract a signal that can be evaluated by inspecting the change in light and dark as multi-value information around the attenuated light quantity.

  On the other hand, when inspecting the shape or the like of the banknote 11, it is necessary to capture the position of the end face of the banknote 11. Therefore, the transmitted light amount from the banknote 11 is about 1/2 to 1/5 of the illumination light amount. If “None” can be determined, the function is satisfied. However, if the amount of light is increased more than necessary, the transmitted light area becomes large at the end face of the banknote 11 due to the effect of diffraction by illumination light or the blur of the pixels of the light receiving element, and the end face position cannot be measured correctly.

  As described above, since there is a difference in the amount of transmitted light to be evaluated between the two transmitted light detection optical systems, optimization adjustment of the amount of illumination suitable for each application is required. Therefore, the illumination unit 14 is set with optimal illumination conditions for each inspection application, as will be described later.

  FIG. 4 schematically shows the configuration of the shape / watermark detection apparatus 135 according to the present embodiment. Each LED chip LR for infrared light of the illumination unit 14 is driven by the illumination drive unit 41, and each LED chip LW for visible light is driven by the illumination drive unit 42. The illumination driving units 41 and 42 are configured to drive the LED chips LR and LW under optimal illumination conditions so that the illumination light amount is adapted to the application.

  The first light receiving element 19 and the second light receiving element 20 are subjected to scanning control and exposure control by the light receiving unit control unit 43. In that case, even when the conveyance speed of the banknote 11 is different for each product to be mounted, the frequency of the drive signal for scanning the light receiving element can be changed.

  Each analog signal from the first light receiving element 19 and the second light receiving element 20 is amplified to an appropriate output signal level by the light receiving amplification sections 44 and 45, respectively, and then sent to the A / D conversion sections 46 and 47, respectively. It is quantized (digitized). The signals quantized by the A / D conversion units 46 and 47 are sent to the transmission image processing unit 48 and the projection image processing unit 49 according to the respective inspection purposes, where correction processing and the like are performed.

  The processing result of the transmission image processing unit 48 is sent to the transmission image correction processing unit 50, and the processing result of the projection image processing unit 49 is sent to the shape / position / defect detection unit 51. The processing result of the transmission image correction processing unit 50 is sent to the watermark detection unit 52, and the detection result of the shape / position / defect detection unit 51 is sent to the transmission image correction processing unit 50. The detection results of the watermark detection unit 52 and the shape / position / defect detection unit 51 are sent to the CPU 155 of the inspection unit 116 (see FIG. 19). Details of these units 48 to 52 will be described in the following explanation of operations.

The operation of the shape / watermark detection apparatus 135 configured as described above will be described below.
When the banknote 11 is transported in the direction of the arrow a by the transport rollers 12 and 13 and reaches the position of the illumination unit 14, the banknote 11 receives mixed illumination light composed of infrared light and visible light by the illumination unit 14 in the transport direction a. Irradiated in a line in a direction orthogonal to

  The transmitted light from the banknote 11 by the light irradiation of the illuminating unit 14 is guided to the dichroic mirror 21 through the imaging unit 18 in the light receiving unit 17, where it is separated into two wavelength lights, and infrared light (transmitted) Infrared light) enters the first light receiving element 19, and visible light (transmitted visible light) enters the second light receiving element 20, and is converted into an electric signal.

  Each output signal (analog signal) of the first light receiving element 19 and the second light receiving element 20 is amplified to an appropriate output signal level by the light receiving amplification units 44 and 45, and then sent to the A / D conversion units 46 and 47. Here, it is quantized (digitized) into a transmitted infrared light image and a transmitted visible light image.

  The transmitted infrared light image obtained from the A / D conversion unit 46 is sent to the transmission image processing unit 48, and the transmitted visible light image obtained from the A / D conversion unit 47 is sent to the projection image processing unit 49, where correction is performed. Processing is performed.

  As the correction processing, for example, shading correction for directly receiving illumination light in a state where the banknote 11 is not present on the transport path and correcting a difference (distortion) in signal level due to brightness and light receiving element sensitivity variations, A function for maintaining stable inspection performance is realized by performing output signal level correction to keep brightness fluctuations due to changes with time and temperature changes constant.

  Further, the projected image processing unit 49 changes the transmitted light from “bright” to “dark” and “dark” to “bright” from the transmitted visible light image from the A / D converter 47 as shown in FIG. The changing position information is extracted as coordinate information. The coordinate information includes the number of pixels in the scanning (scanning) direction (scanning direction of the light receiving element) b in the entire scanning range E1 from the coordinate value “0, 0” to the coordinate value “m, n”, and the movement of the banknote 11. This is a coordinate value indicating the number of scans in the (conveyance) direction a.

  Based on the end face position coordinate value of the bank note 11 (hereinafter also referred to as the medium end face position coordinate value), coordinate information that is the origin of where the bank note 11 is located within the entire scanning range E1 is extracted. At the same time, even when there is a transmitted light region inside the banknote 11 such as a hole or a tear located inside from the end face of the banknote 11, the change position coordinate information from “dark” to “bright” is also extracted. To do.

  Next, the shape / position / deletion detection unit 51 calculates the coordinate values (0, a), (0, b), (c, a), FIG. 5 from the coordinate information acquired by the projected image processing unit 49. By specifying the four points (d, b), the end face position of the banknote 11 is detected. Next, two opposite corners of the four corners of the banknote 11 are connected (indicated by broken lines), and the position coordinate value of the intersecting point is recognized as the barycentric coordinate value g. Based on the position of the center of gravity (the center of gravity coordinate value g), the amount of deviation of the standard transport center (the center point in the transport direction) of the banknote 11 in the scan direction b in the scan direction b is calculated. This deviation amount is a slide amount, and is an amount for judging how far the banknote 11 is away from the standard transport center.

  Subsequently, as shown in FIG. 6, the difference in the scanning direction b is calculated from the two corner coordinate values (0, e) and (f, g) in the long side direction of the banknote 11. This difference is extracted as a feature value for judging the inclination (skew) of the banknote 11. This feature amount is also calculated from the two corner coordinate values (h, i) and (j, k) on the opposite side, and two pieces of information are obtained. The larger value is adopted as the value for obtaining the skew amount, and the skew amount is determined from the length information of the banknote 11 in the long side direction. Similarly, a coordinate value difference in the conveyance direction of two corners in the short side direction of the banknote 11 is obtained, and the validity of the skew determination is verified. When there is a large difference between the mutual detection amounts, a determination process such as adopting the maximum value is performed.

  As in the example shown in FIG. 7, when there are missing portions 11 a at part of the four corners of the banknote 11, the end face position is verified to verify that it is rectangular so that no error occurs in the calculation of the slide amount and the skew amount. Anomalies are detected by checking the continuity of coordinates. When the corner missing portion 11a is recognized, a virtual corner coordinate value is obtained from the continuity of the end face position information. By using the virtual corner coordinate values, the slide amount and the skew amount are calculated to avoid erroneous detection.

  Similarly, from the coordinate information acquired by the projected image processing unit 49, the outer shape and dimensions of the banknote 11, and if transmitted light exists inside the outer shape of the banknote 11, such as a hole or a tear Detect missing information. FIG. 8 is a diagram showing a slide state in which the banknote 11 is moved in parallel with the scanning direction b, and the amount of slide is obtained from the displacement of the center of gravity. FIG. 9 shows a case where slides and skews are mixed in the banknote 11, and the slide amount and skew amount are calculated by the above-described method, and the conveyance state and the position of the banknote 11 are specified.

  Next, the transmission image correction processing unit 50 extracts a watermark image area to be inspected (an area where the watermark image P exists) from the transmission infrared light image corrected by the transmission image processing unit 48, and transmits the transmission image. Extracts density changes and brightness information using a dedicated algorithm. At this time, the watermark image area is extracted by acquiring the skew amount and the slide amount based on the passing position information of the banknote 11 from the shape / position / defect detection unit 51 and inputting the skew amount and the slide amount based on the skew amount and the slide amount. Correction processing for rotating and moving the transmitted infrared light image using a technique such as affine transformation is performed.

  FIG. 10 is a conceptual diagram in the case where the same position condition as that of the dictionary image Rp equivalent to the case of normal conveyance is obtained by the rotation correction of the skewed input image (transmission infrared light image) Ia (or Ib). Show. By this correction processing, the collation processing in the watermark detection unit 52 at the subsequent stage can be realized with high accuracy.

  Further, the transparent image correction processing unit 50 acquires information such as the denomination, front and back sides, and passing direction of the banknote 11 from the CPU 155 (see FIG. 19) of the inspection unit 116, and performs watermark detection processing from these information. The watermark image area is detected and cut out, and the image information in the watermark image area is output to the watermark detection unit 52.

  Further, as shown in FIG. 11, the transparent image correction processing unit 50 compares the watermark image P with the size of the missing portion 11 b such as a hole in the watermark image P of the banknote 11. If it is sufficiently small, the surrounding area 11c including the defect portion 11b is excluded from the watermark image area. The accuracy of this function can be realized with higher accuracy as the image reading resolution is smaller.

  The watermark detection unit 52 matches the image information in the watermark image area supplied from the transmission image correction processing unit 50 with a preset genuine watermark image (dictionary information), density information, transmitted light amount, and the like. Use various information to evaluate the authenticity of the watermark image.

  The detection result of the shape / position / deletion detection unit 51 and the evaluation result of the watermark detection unit 52 are sent to the CPU 155 of the inspection unit 116 as one of the parameters for performing the type determination and authenticity determination of the banknote 11. Used.

  FIG. 12 shows how the position of the watermark image P of the banknote 11 to be inspected fluctuates due to the positional deviation during conveyance. The conditions for determining the amount of variation were as follows: the banknote 11 had a length of 160 mm, the banknote 11 had a width of 82 mm, a positional deviation amount of ± 5 mm, and a rotation amount of ± 5 °. As shown in this figure, it can be seen that the inspection target position changes greatly when the conveyance position deviation allowable range of the banknote 11 is widened. At the same time, it can be seen that the detection position correction function is important.

According to at least one embodiment described above, the following effects can be expected.
(1) Securing the number of inspection devices that can be installed in banknote processing machines and supporting higher speeds
By installing optical means that simultaneously inspects the shape and defects of banknotes at the same position in the device that inspects the watermark images of banknotes, it is possible to improve the authenticity discrimination performance of watermark images, and on the banknote transport path The number of mounted units can be reduced from two to one. Originally, one unit space can be used for different authenticity items because of the limit on the number of units that can be mounted, which contributes to the improvement of the overall authenticity performance as a device and also contributes to cost reduction. Further, it is possible to reduce the size of the device for the reduced space.

(2) Reduction of mis-identification due to transport variations and watermark inspection field shift
Acquire bad effects on inspection performance due to fluctuations in position deviation and rotation when banknotes move by effectively using the position and rotation information of banknotes acquired at the same position where the watermark image is inspected. It is possible to accurately capture the watermark image detection area of the image. As a result, it is possible to always achieve high authenticity discrimination performance without relaxing the inspection threshold, and it is possible to inspect almost the entire area of the security element without narrowing the area where the banknotes are present. In addition, since the position of the banknote to be inspected can be accurately grasped, comparison and evaluation with reference data can be performed while reading and disassembling, and inspection with finer image information becomes possible.

(3) Reducing the effect of true / false inspection performance on missing inspection target positions
When the security element of the banknote that inspects the watermark image is damaged, the defect information of the banknote by the projection information acquired at the same position is effectively used, and the defect is compared with the inspection area of the watermark image. If it is not large, the area including the periphery of the defect position can be excluded from the inspection target, and the watermark image detection determination process can be performed. As a result, it is possible to realize true / false discrimination performance that is not affected by defects, and it is possible to reduce the rejection rate while maintaining the true / false performance when inspecting bad banknotes with many damages.

  In the above-described embodiment, the LED chip LR that emits infrared light as the illumination unit 14 includes a plurality of LED chips 15 arranged in a straight line at regular intervals in a direction orthogonal to the conveyance direction a of the banknotes 11. And LED chips LW that emit visible light are arranged in every other line to realize mixed color illumination light in which infrared light and visible light are mixed. For example, as shown in FIG. A transparent structure body (rod optical body) 22 of the type is arranged in a direction orthogonal to the transport direction of the banknotes 11 and irradiated with illumination light from both end faces of the transparent structure body 22, respectively. You may make it obtain a linear illumination light seeing.

  In this case, the mixed illumination light of infrared light and visible light includes LEDs (light emitting elements) 23 and 23 that emit infrared light on both end surfaces of the transparent structure 22, LEDs 24 and 24 that emit visible light, and dichroic, respectively. It can be realized by arranging mirrors 25 and 25 and irradiating infrared light from LEDs 23 and 23 and visible light from LEDs 24 and 24 from both end faces of transparent structure 22 via dichroic mirrors 25 and 25, respectively. is there. In this example, the illumination diffusion plate 16 may be omitted.

  Further, as the illumination unit 14, for example, as shown in FIG. 14, a transmission light type transparent structure (rod optical body) 26 is arranged in a direction orthogonal to the transport direction of the banknotes 11, and the transparent structure 26. By irradiating illumination light from both end faces of the light source, linear illumination light as viewed from the light receiving unit 17 may be obtained.

  In this case, the mixed illumination light of infrared light and visible light is light sources 27 and 27 having a broad emission wavelength, such as a halogen lamp, on both end surfaces of the transparent structure 26, and optical filters (visible light absorbing infrared light). A light transmission filter) 28 and an optical filter (infrared light absorption visible light transmission filter) 29 are provided, and light from the light sources 27, 27 is respectively transmitted from both end faces of the transparent structure 26 via the optical filters 28, 29. It can be realized by irradiation. Also in this example, the illumination diffusing plate 16 may be omitted.

  The optical filters 28 and 29 having common light transmission characteristics can also be used. In this case, the optical filters 28 and 29 are provided with transmission spectral characteristics that allow the light receiving unit 17 to balance the light amount between visible light and infrared light.

  Further, as the light receiving unit 17, for example, as shown in FIG. 15, Selfoc lenses (registered trademark) 30 and 31 that are self-focusing imaging lenses, optical filters (visible light absorbing infrared light transmitting filters) 32, A combination of the optical filter (infrared light absorption visible light transmission filter) 33 and the contact image sensors 34 and 35 can also be realized.

  Further, as the light receiving unit 17, for example, as shown in FIG. 16, imaging lenses 36 and 37, an optical filter (visible light absorbing infrared light transmitting filter) 32, and an optical filter (infrared light absorbing visible light transmitting filter) 33. And a combination of the contact image sensors 34 and 35.

  In the above-described embodiment, a method is described in which the input image is rotated or moved by the transparent image correction processing unit 50 and collated with the dictionary image generated at the standard position. The same effect can be obtained by a method of receiving the skew amount and the slide amount based on the medium passage position information of the banknote 11 from the position / deletion detecting unit 52 and performing the collation process by rotating or moving the dictionary image.

  Furthermore, although the said embodiment demonstrated the case where paper sheets were banknotes, it is not limited to this, For example, even if it is securities other than a banknote, it is applicable similarly.

Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.
The invention described in the scope of the claims at the beginning of the present application is added below.
[1]
A first light source for irradiating light having a first wavelength on one surface of the conveyed paper sheet;
A second light source that irradiates light having a second wavelength at the same position as the light irradiation by the first light source on one surface of the conveyed paper sheet;
A first light beam is provided on the other surface side of the transported paper sheet, receives light having a first wavelength transmitted through the paper sheet by light irradiation of the first light source, and converts it into an electrical signal. Light receiving means,
A second light source is provided on the other surface side of the transported paper sheet and receives light having a second wavelength transmitted through the paper sheet by light irradiation of the second light source and converts it into an electrical signal. Light receiving means,
An optical reader comprising:
[2]
[1] The optical reading device according to [1], wherein the light receiving optical axes of the first and second light receiving means are set to the same position on the paper sheet.
[3]
[1] The optical reading apparatus according to [1], wherein the light receiving optical axes of the first and second light receiving means are set to the same position from the paper sheet to the light receiving portions of the first and second light receiving means.
[4]
A first light source that irradiates infrared light onto one side of a paper sheet that has a watermark image and a printed image and is conveyed;
A second light source that irradiates visible light at the same position as the light irradiation by the first light source on one surface of the conveyed paper sheet;
Infrared light that is provided on the other surface side of the conveyed paper sheet and receives infrared light transmitted through the paper sheet by light irradiation of the first light source and converts it into an electrical signal. First light receiving means for acquiring an image;
Provided on the other surface side of the transported paper sheet, the visible light transmitted through the paper sheet by light irradiation of the second light source is received and converted into an electrical signal, whereby a transmitted visible light image is obtained. A second light receiving means to obtain;
An optical reader comprising:
[5]
Detecting means for acquiring a projected image of the paper sheet based on the transmitted visible light image acquired by the second light receiving means, and detecting the shape and position of the paper sheet based on the acquired projected image;
Watermark image area specification that specifies a watermark image area in which the watermark image exists based on the shape and position information of the paper sheet detected by the detection means from the transmitted infrared light image acquired by the first light receiving means Means,
[4] The optical reading device according to [4].
[6]
Detecting means for acquiring a projected image of the paper sheet based on the transmitted visible light image acquired by the second light receiving means, and detecting the shape, position and defect of the paper sheet based on the acquired projected image; ,
From the transmitted infrared light image acquired by the first light receiving means, the watermark image area where the watermark image exists is specified based on the shape and position information of the paper sheets detected by the detection means, and the detection Watermark image area identifying means for excluding the missing portion from the identified watermark image area based on the defect information of the paper sheet detected by the means;
[4] The optical reading device according to [4].
[7]
The watermark image area specifying means is a shape and position information of paper sheets detected by the detecting means from the transmitted infrared light image acquired by the first light receiving means, and the paper sheets supplied from the outside. The optical reading apparatus according to [5] or [6], wherein a watermark image area in which the watermark image exists is specified based on the type information and the conveyance direction information.
[8]
Conveying means for conveying a paper sheet having a watermark image and a printed image;
A first light source for irradiating one surface of the paper sheet conveyed by the conveying means with infrared light;
A second light source that irradiates visible light at the same position as the light irradiation by the first light source on one surface of the paper sheet conveyed by the conveying means;
Provided on the other surface side of the paper sheet transported by the transport means, and receives infrared light transmitted through the paper sheet by light irradiation of the first light source and transmits it by converting it into an electrical signal. A first light receiving means for acquiring an infrared light image;
Visible light is provided on the other surface side of the paper sheet transported by the transport means, and receives visible light transmitted through the paper sheet by light irradiation of the second light source and converts it into an electrical signal so that it can be transmitted and visible. A second light receiving means for acquiring an optical image;
Determination means for detecting the watermark image of the paper sheet based on the transmitted infrared light image acquired by the first light receiving means, and determining its authenticity;
Detecting means for detecting the shape and defect of the paper sheet based on the transmitted visible light image acquired by the second light receiving means;
Sorting processing means for sorting paper sheets conveyed by the conveying means according to the determination result of the determining means and the detection result of the detecting means;
A paper sheet processing apparatus comprising:
[9]
Conveying means for conveying a paper sheet having a watermark image and a printed image;
A first light source for irradiating one surface of the paper sheet conveyed by the conveying means with infrared light;
A second light source that irradiates visible light at the same position as the light irradiation by the first light source on one surface of the paper sheet conveyed by the conveying means;
Provided on the other surface side of the paper sheet transported by the transport means, and receives infrared light transmitted through the paper sheet by light irradiation of the first light source and transmits it by converting it into an electrical signal. A first light receiving means for acquiring an infrared light image;
Visible light is provided on the other surface side of the paper sheet transported by the transport means, and receives visible light transmitted through the paper sheet by light irradiation of the second light source and converts it into an electrical signal so that it can be transmitted and visible. A second light receiving means for acquiring an optical image;
Detecting means for acquiring a projected image of the paper sheet based on the transmitted visible light image acquired by the second light receiving means, and detecting the shape, position and defect of the paper sheet based on the acquired projected image; ,
Watermark image area specification that specifies a watermark image area in which the watermark image exists based on the shape and position information of the paper sheet detected by the detection means from the transmitted infrared light image acquired by the first light receiving means Means,
Determination means for extracting the watermark image of the paper sheet from the watermark image area specified by the watermark image area specifying means, and determining the authenticity thereof;
Sorting processing means for sorting paper sheets conveyed by the conveying means according to the determination result of the determining means and the detection result of the detecting means;
A paper sheet processing apparatus comprising:

  DESCRIPTION OF SYMBOLS 11 ... Banknote (paper sheets), P ... Watermark image, 12, 13 ... Conveyance roller (conveyance path), 14 ... Illumination part, 15 ... LED chip, 16 ... Illumination diffuser plate, 17 ... Light receiving part, 18 ... Connection Image means, 19 ... first light receiving element, 20 ... second light receiving element, 21 ... dichroic mirror, 48 ... transmission image processing section, 49 ... projection image processing section, 50 ... transmission image correction processing section, 51 ... shape / position / Defect detection unit, 52 ... Watermark detection unit, 111 ... Paper sheet processing device, 112 ... Supply unit, 113 ... Extraction unit, 115 ... Conveyance path (conveyance means), 116 ... Inspection unit, 120-125 gate, 126 ... Exclusion transport path, 127... Exclusion stacking unit, 128 to 131... Stacking / bundling unit, 135.

Claims (5)

A first light source that irradiates one surface of a paper sheet having a watermark image with infrared light ;
A second light source that irradiates visible light at the same position as the light irradiation by the first light source on one surface of the conveyed paper sheet;
Wherein provided on the other surface side of the sheet being conveyed, the first light source of the transmitted the infrared first transmission by converting light into electrical signals by receiving the paper sheet by light irradiation A first light receiving means for acquiring an optical image ;
Wherein provided on the other surface side of the sheet being conveyed, the second transmitted light by the light irradiation of the second light source is converted into an electric signal by receiving the visible light transmitted through the paper sheet A second light receiving means for acquiring an image ;
Detecting means for acquiring a projected image of the paper sheet based on the second transmitted light image acquired by the second light receiving means, and detecting the shape and position of the paper sheet based on the acquired projected image; ,
A watermark image area specification that specifies a watermark image area in which the watermark image exists from the first transmitted light image acquired by the first light receiving means based on the shape and position of the paper sheet detected by the detection means. Means,
Equipped with,
The light receiving optical axes of the first and second light receiving means are at the same position on the paper sheet,
Each light receiving optical axis of the first and second light receiving means is in the same position from the paper sheet to the light receiving part of the first and second light receiving means,
Optical reader. The detection means further detects the skew of the paper sheet based on the acquired projection image,
The watermark image area specifying means specifies the watermark image area further based on the skew detected by the detecting means;
The optical reader according to claim 1. It said detecting means, based on the acquisition the projection image, and further detects a lost portion of the paper sheet,
The watermark image area specifying means specifies a watermark image area excluding the detected deficient portion by pre-Symbol detection means,
The optical reading device according to claim 1 . The watermark image area specifying means from said first first transmitted light image obtained by the light receiving unit, the paper sheet supplied from the external shape and position information of the detected the paper sheet by the detection unit Identifying a watermark image area in which the watermark image exists based on the type information and the transport direction information ;
The optical reading device according to claim 1 . Conveying means for conveying a paper sheet having a watermark image and a printed image;
A first light source that irradiates one surface of the paper sheet conveyed by the conveying means with infrared light ;
A second light source that irradiates visible light at the same position as the light irradiation by the first light source on one surface of the paper sheet conveyed by the conveying means;
Provided on the other side of the paper sheet conveyed by said conveying means, be converted into an electric signal by receiving the infrared light transmitted through the paper sheet by the light irradiation of the first light source A first light receiving means for acquiring a first transmitted light image by:
Provided on the other surface side of the paper sheet conveyed by said conveying means, by converting into an electric signal by receiving the visible light transmitted through the paper sheet by the light irradiation of the second light source A second light receiving means for acquiring a second transmitted light image ;
Detecting means for acquiring a projected image of the paper sheet based on the second transmitted light image acquired by the second light receiving means, and detecting the shape and position of the paper sheet based on the acquired projected image; ,
A watermark image area specification that specifies a watermark image area in which the watermark image exists from the first transmitted light image acquired by the first light receiving means based on the shape and position of the paper sheet detected by the detection means. Means,
Determination means for detecting the watermark image of the paper sheet from the watermark image area specified by the watermark image area specifying means, and determining the authenticity of the paper sheet based on the detected watermark image ;
Sorting processing means for sorting paper sheets conveyed by the conveying means according to the determination result of the determining means and the detection result of the detecting means;
Equipped with,
The light receiving optical axes of the first and second light receiving means are at the same position on the paper sheet,
Each light receiving optical axis of the first and second light receiving means is in the same position from the paper sheet to the light receiving part of the first and second light receiving means,
Paper sheet processing equipment.

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