A banknote optical detection module and a banknote testing device using the same

Abstract

The utility model discloses a paper currency optical detection module and application its's currency detector, and its light source includes side light source, coaxial light source and transmission light source, and side light source is obliquely arranged in the casing, and the casing has a vertical side wall, and coaxial light source is vertically arranged in the vertical side wall, and the light shield is arranged between side light source and coaxial light source, and transmission light source is located the other side of vertical side wall and is horizontally arranged, and cylindrical lens is vertically arranged in the casing and is located the below of half -and -half lens, and side light source above is oblique to the side of cylindrical lens, and half -and -half lens and side light source are oblique to the same side, and image sensor is located the below of cylindrical lens. The currency detector includes two groups of paper currency optical detection modules separately arranged above and below the currency passageway, and the lower transmission light source is aligned with the upper cylindrical lens. The utility model can effectively detect transparent tape, and the discoloration characteristics of the photochromic ink can be distinguished by the image of coaxial light, and the accuracy of distinguishing the authenticity of paper currency is improved.

Description

Technical Field

[0001] This utility model relates to the field of sensor equipment technology, and more specifically to a banknote optical detection module and a banknote verification device using the same. Background Technology

[0002] Existing banknote verification devices have two optical detection modules (i.e., contact image sensor scanners, or CIS for short). As the banknote passes through the channel, the upper and lower CIS modules capture scanned images of the banknotes. The processed image features are then used to determine the authenticity of the banknotes. The structure of existing banknote verification devices is as follows: Figure 1 As shown, while existing equipment possesses functions such as R, G, B, IR light reflection imaging, ultraviolet light reflection imaging, and infrared light transmission imaging, it has certain limitations in detecting whether transparent tape is adhered to banknotes. The presence of transparent tape may affect the authenticity of the banknotes. The reason for the presence of transparent tape is that banknotes often tear or become damaged over time, and people frequently use transparent tape to repair them and continue using them. Due to the light emission angle problem between traditional reflective light sources and banknotes, transparent tape cannot be effectively detected. Therefore, an additional detection device is required specifically for detecting transparent tape, such as a thickness sensor, ultrasonic sensor, magnetic sensor, etc. This not only increases costs but also makes the device bulky.

[0003] In addition, banknote images feature serial numbers, portrait watermarks, white watermarks, optically variable windowed security threads, security threads, color-changing ink, fluorescent ink, and fluorescent fibers. However, due to structural limitations in the light source angle, existing optical detection modules cannot identify some features, such as holographic security threads and optically variable windowed security threads, nor can they recognize the features of optically variable ink. Summary of the Invention

[0004] To address the aforementioned issues, this invention provides a banknote optical detection module and a banknote verification device using the same. This module can effectively detect transparent tape without increasing the size of the equipment. It can also identify the color-changing characteristics of optically variable ink from different viewing angles using images from coaxial light, thereby improving the accuracy of banknote authentication.

[0005] According to one aspect of the present invention, a banknote optical detection module is provided, comprising: The housing has a light-transmitting glass plate on it, and the upper surface of the light-transmitting glass plate forms a scanning surface that mates with the workpiece to be scanned. The light source includes a side-lit light source, a coaxial light source, and a transmissive light source. The side-lit light source is inclined relative to the scanning surface and is installed inside the housing. The housing has a vertical sidewall. The coaxial light source is vertically installed on the vertical sidewall. A light cover is provided between the side-lit light source and the coaxial light source. The transmissive light source is located on the other side of the vertical sidewall and is horizontally installed relative to the scanning surface. A semi-reflective mirror, wherein the semi-reflective mirror and the side-lit light source are tilted to the same side; A cylindrical lens is vertically disposed inside the housing and located below the semi-reflective lens, with the side-emitting light source tilted towards the side where the cylindrical lens is located. An image sensor is mounted on a PCB substrate and fixed inside a housing, with the image sensor located below a cylindrical lens.

[0006] In some embodiments, the light-transmitting glass plate is horizontally positioned, the semi-reflective mirror is tilted at 45° to the horizontal plane, and the side-lit light source is tilted at 35-45° to the horizontal plane. The semi-reflective mirror is positioned at 45° so that the coaxial light source is reflected perpendicularly onto the surface of the workpiece to be scanned, and also so that the refracted light can enter the cylindrical lens perpendicularly.

[0007] In some implementations, the photomask is made of glass and coated with black paint.

[0008] In some implementations, the side-lit light source is an RGBIRUV light source, the coaxial light source is an RGBIR light source, and the transmitted light source is an IR light source.

[0009] In some embodiments, the housing has a first receiving groove for placing a photomask and a second receiving groove for placing a transmissive light source. The height of the first receiving groove is lower than the position of the light emitted by the coaxial light source, and the upper part of the second receiving groove has an inlet that is wider at the top and narrower at the bottom.

[0010] According to another aspect of the present invention, a banknote verification device using the above-mentioned banknote optical detection module is provided. The banknote verification device has two sets of banknote optical detection modules, which are respectively arranged above and below the banknote passage. The transmission light source of the lower banknote optical detection module is aligned with the cylindrical lens of the upper banknote optical detection module.

[0011] Compared with existing technologies, the beneficial effects of this utility model are as follows: The banknote optical detection module provided by this utility model includes various light sources, such as RGBIRUV side-emitting light sources, RGBIR coaxial light sources, and IR transmission light sources. The light emitted from the side-emitting light source is directed towards the surface of the object to be scanned. After reflection from the surface, it is refracted by a semi-reflective lens, and the refracted light is received by an image sensor through a cylindrical lens. The light emitted from the coaxial light source, after passing through the semi-reflective lens, is partially reflected onto the surface of the object to be scanned. The light reflected by the semi-reflective lens onto the surface of the object is perpendicular to the transparent glass plate, and after further reflection, it is refracted by the semi-reflective lens again, and the refracted light is received by an image sensor through a cylindrical lens. The other portion of the light passes directly through the semi-reflective lens to refract, and the refracted light is received by an image sensor through a cylindrical lens. The light emitted from the transmission light source is directed perpendicularly towards the surface of the object to be scanned. Therefore, in addition to scanning reflected light and transmitted light images as in existing detection modules, it also provides a coaxial light image.

[0012] The application of this new banknote optical detection module to banknote verification devices not only provides the counterfeit detection function of general financial banknote verification instruments, but also has the functions of detecting special optically variable ink and optically variable perforated windowed security threads on banknotes, as well as detecting whether transparent tape is attached.

[0013] Transparent tape is a reflective material with a smooth surface and total internal reflection. Light emitted from a coaxial light source is reflected by a semi-reflective lens and then incident perpendicularly on the surface of the object to be scanned, where the transparent tape is attached. After being reflected by the transparent tape, the light is refracted by the semi-reflective lens and then incident perpendicularly into the cylindrical lens. When light is incident perpendicularly on a smooth surface, the reflectivity is very high. There will be an output difference between the tape and non-tape areas, which can screen out banknotes with transparent tape attached without the need for special detection equipment such as thickness sensors.

[0014] Because the incident angle of a coaxial light source is different from that of a side-lit light source, it affects the color performance of photochromic inks. The color of photochromic inks changes with the incident angle of the light source. When illuminated by coaxial light, the color of the ink will be different from that under side lighting. This difference makes the color detection and identification of objects more accurate under different lighting conditions, further improving the ability to identify material properties. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of an existing optical detection module; Figure 2 This is a schematic diagram of the structure of a banknote optical detection module according to this utility model; Figure 3 This is a schematic diagram of the banknote optical detection module proposed in this utility model applied to a banknote verification device; Figure 4 It is a path diagram of a portion of the light emitted from a coaxial light source; Figure 5 It is a scanned image of a banknote with transparent tape attached, in which, Figure 5 A is a scanned image from an existing optical inspection module. Figure 5 B is a scanned image of this application; Figure 6 The holographic security thread scan image on the banknote, in which, Figure 6 A is a scanned image from an existing optical inspection module. Figure 6 B is a scanned image of this application; Figure 7 It is a scanned image of the optically variable security thread with a window on the banknote, in which... Figure 7 A is a scanned image from an existing optical inspection module. Figure 7 B is a scanned image of this application; Figure 8 This is a color gradation comparison chart of the optically variable security thread with perforated windows on banknotes scanned by the old and new optical detection modules. Detailed Implementation

[0016] The present invention will be further described below with reference to specific embodiments.

[0017] like Figure 2 As shown, an optical banknote detection module according to one embodiment of the present invention can be applied in a banknote verification device. The optical banknote detection module includes: a housing 1, a light source, a semi-reflective lens 5, a cylindrical lens 6, and an image sensor 7.

[0018] A light-transmitting glass plate 2 is mounted on the top of the housing 1. The light-transmitting glass plate 2 is horizontally positioned, and its upper surface forms a scanning surface 21 that mates with the object to be scanned. An image sensor 7 is encapsulated on a PCB substrate 71, which is fixed to the bottom of the housing 1. The image sensor 7 faces upward, and a cylindrical lens 6 is mounted directly above it. A semi-reflective mirror 5 is obliquely mounted above the cylindrical lens 6, with the angle A between the semi-reflective mirror 5 and the horizontal plane being 45°. A light source is installed inside the housing 1, specifically including a side-emitting light source 31, a coaxial light source 32, and a transmissive light source 33. The angle B between the side-emitting light source 31 and the horizontal plane is 35° to 45°, and the side-emitting light source 31 and the semi-reflective mirror 5 are tilted to the same side. In this embodiment, the cylindrical lens 6 is located on the left side of the housing 1, the semi-reflective mirror 5 is tilted with the left side higher than the right, and the light-emitting surface of the side-emitting light source 31 also faces the left side. The housing 1 has a vertical sidewall 11. A coaxial light source 32 is vertically mounted on the vertical sidewall 11, with its light-emitting surface facing the side where the semi-reflective lens 5 is located. A photomask 4 is provided between the side-emitting light source 31 and the coaxial light source 32. The photomask 4 is made of glass and its surface is coated with black paint. A transmission light source 33 is located on the other side of the vertical sidewall 11, that is, on the right side of the housing 1. The transmission light source 33 is horizontally positioned relative to the scanning surface 21, and its light-emitting surface faces the light-transmitting glass plate 2.

[0019] In this embodiment, the side-lit light source 31 is an RGBIRUV light source, the coaxial light source 32 is an RGBIR light source, and the transmitted light source 33 is an IR light source. Wherein, R represents red light, G represents green light, B represents blue light, IR represents infrared light, and UV represents ultraviolet light.

[0020] The housing 1 has corresponding mounting slots or surfaces for mounting the light source, the semi-reflective mirror 5, and the cylindrical lens 6. For example, the semi-reflective mirror 5 has a 45° inclined mounting surface. The housing 1 has a first receiving slot 12 for placing the photomask 4. The height of the first receiving slot 12 must be lower than the position of the light emitted by the coaxial light source 32 so as not to affect the effective emission of the coaxial light source 32. The housing 1 has a second receiving slot 13 for placing the transmissive light source 33. The upper part of the second receiving slot 13 has an inlet 131 that is wider at the top and narrower at the bottom.

[0021] The paths of each light source are as follows, combined with... Figure 3 To elaborate further: The light emitted by the side-lit light source 31 is directed toward the surface of the object to be scanned. After being reflected by the surface of the object to be scanned, the reflected light is generated. The reflected light passes through the semi-reflective lens 5 to generate refracted light. The refracted light enters the cylindrical lens 6 and is received by the image sensor 7.

[0022] The light emitted from the coaxial light source 32, after passing through the semi-reflective lens 5, has a portion reflected onto the surface of the workpiece to be scanned. This reflected light, perpendicular to the transparent glass plate, is then reflected again by the workpiece surface and refracted by the semi-reflective lens 5. The refracted light is then received by the image sensor 7 via the cylindrical lens 6 (e.g., ...). Figure 4 (As shown in the image); another portion of the light passes directly through the semi-reflective lens 5 to generate refracted light, which is then received by the image sensor 7 via the cylindrical lens 6.

[0023] The light emitted by the transmission light source 33 is directed perpendicularly to the surface of the object to be scanned. The light passes through the semi-reflective lens 5 and the cylindrical lens 6 of the optical detection module on the opposite side and is then received by the image sensor 7.

[0024] This novel optical inspection module, in addition to scanning reflected light and transmitted light images as in existing inspection modules, also features a coaxial light image. The semi-reflective mirror 5 is positioned at 45°, allowing the coaxial light source 32 to be perpendicularly reflected onto the surface of the workpiece to be scanned, and also allowing refracted light rays to enter the cylindrical lens 6 perpendicularly.

[0025] The aforementioned banknote optical detection module is applied to banknote verification devices, such as... Figure 3 As shown, in application, the banknote verification device has two sets of banknote optical detection modules, which are respectively positioned above and below the banknote passage 100. The transmission light source 33 of the lower banknote optical detection module needs to be aligned with the cylindrical lens 6 of the upper banknote optical detection module. In this way, the light emitted by the transmission light source 33 is directed perpendicularly to the surface of the object to be scanned. After passing through the semi-reflective lens 5 and cylindrical lens 6 of the opposite optical detection module, the light is received by the image sensor 7 on the opposite side.

[0026] The banknote optical detection module provided by this utility model includes a variety of different light sources, specifically an RGBIRUV side-emitting light source 31, an RGBIR coaxial light source 32, and an IR transmission light source 33. When applied to a banknote verification device, it not only has the counterfeit detection function of a general financial banknote verification instrument, but also has the function of detecting special optically variable ink and optically variable perforated windowed security thread on banknotes, as well as detecting whether transparent tape is attached.

[0027] Because transparent tape is a reflective material with a smooth surface and total internal reflection, the light emitted by the coaxial light source 32 is reflected by the semi-reflective lens 5 and then incident perpendicularly on the surface of the object to be scanned with transparent tape. After being reflected by the transparent tape surface, it is refracted by the semi-reflective lens 5 and incident perpendicularly into the cylindrical lens 6. When the light is incident perpendicularly on a smooth surface, the reflectivity is very high. There will be an output difference in the area with and without tape, which can screen out banknotes with transparent tape, without the need for special detection equipment such as thickness sensors.

[0028] like Figure 5 The optical detection module for banknotes proposed in this application and the optical detection module in the prior art, wherein, Figure 5 Image A is a scanned image from an existing optical detection module. The color gradation difference between the transparent tape area and the background area is not significant, making it difficult to identify the transparent tape. Figure 5 Image B is a scanned image from the new optical detection module. It can be seen that the brightness of the transparent tape area is extremely high, and the color gradation difference between it and the background area is large, making it easy to identify.

[0029] Since the incident angle of the coaxial light source 32 is different from that of the side-lit light source 31, it will affect the color performance of the photochromic ink. The color of the photochromic ink will change with the incident angle of the light source. When irradiated with coaxial light, the color display of the ink will be different from that under side lighting. This difference makes the color detection and identification of objects more accurate under different lighting conditions, and further improves the ability to identify material properties.

[0030] like Figure 6 A holographic security thread scan image on a banknote. Figure 6 A is an image scanned using an existing optical detection module, where the holographic security thread cannot be effectively distinguished from the banknote background; Figure 6 Image B is a scanned image using the optical detection module of this application. The color gradation of the holographic security line differs greatly from the background area, and the words "Security Line" can be clearly seen.

[0031] Figure 7 Scan the optically variable security thread with perforated windows on the old and new banknotes. Figure 7 Image A is the image scanned by the existing optical detection module. The color gradation of the optically variable perforated windowed security thread is much lower than that of the banknote background. Figure 7 B is the image scanned by the optical inspection module provided in this application.

[0032] Figure 8 By comparing the color gradations of the optically variable security thread with perforated windows on the old and new structures of the banknotes, the color gradations of the optically variable security thread area can be subtracted from the old structure to obtain a difference value. Only when the difference value is greater than a certain value can it be determined to be a genuine banknote, thus achieving the function of counterfeit detection.

[0033] The main difference between this new banknote optical detection module and existing banknote detection modules is that it replaces the reflected light source in existing banknote detection modules with a coaxial light structure, while retaining the function of reflecting ultraviolet light and transmitting infrared light. It can obtain images of different wavelengths and use the characteristics of the images to identify the authenticity of banknotes.

[0034] The above descriptions are merely some embodiments of this utility model. It should be noted that those skilled in the art can make other modifications and improvements without departing from the inventive concept of this utility model, and these all fall within the protection scope of this utility model.

Claims

1. A banknote optical detection module, characterized in that, include: The housing (1) is provided with a light-transmitting glass plate (2), and the upper surface of the light-transmitting glass plate (2) forms a scanning surface (21) that cooperates with the object to be scanned. The light source includes a side-lit light source (31), a coaxial light source (32), and a transmission light source (33). The side-lit light source (31) is inclined relative to the scanning surface (21) and is installed inside the housing (1). The housing (1) has a vertical sidewall (11). The coaxial light source (32) is vertically installed on the vertical sidewall (11). A light cover (4) is provided between the side-lit light source (31) and the coaxial light source (32). The transmission light source (33) is located on the other side of the vertical sidewall (11) and is horizontally installed relative to the scanning surface (21). A semi-reflective mirror (5) is tilted to the same side as the side-lit light source (31); A cylindrical lens (6) is vertically disposed inside the housing (1) and located below the semi-reflective lens (5). The side-lit light source (31) is tilted towards the side where the cylindrical lens (6) is located. Image sensor (7) is disposed on PCB substrate (71) and fixed inside housing (1), and the image sensor (7) is located below cylindrical lens (6).

2. The banknote optical detection module according to claim 1, characterized in that, The light-transmitting glass plate (2) is set horizontally, the semi-reflective mirror (5) is set at a 45° angle to the horizontal plane, and the side-lit light source (31) is set at a 35-45° angle to the horizontal plane.

3. The banknote optical detection module according to claim 1, characterized in that, The photomask (4) is made of glass and its surface is coated with black paint.

4. The banknote optical detection module according to claim 1, characterized in that, The side-lit light source (31) is an RGBIRUV light source, the coaxial light source (32) is an RGBIR light source, and the transmissive light source (33) is an IR light source.

5. The banknote optical detection module according to claim 1, characterized in that, The housing (1) has a first receiving groove (12) for placing a photomask (4) and a second receiving groove (13) for placing a transmissive light source (33). The height of the first receiving groove (12) is lower than the position of the light emitted by the coaxial light source (32). The upper part of the second receiving groove (13) has an inlet (131) that is wider at the top and narrower at the bottom.

6. A banknote verification device, employing the banknote optical detection module as described in any one of claims 1 to 5, characterized in that, The banknote verification device has two sets of banknote optical detection modules, which are respectively located above and below the banknote passage (100). The transmission light source (33) of the lower banknote optical detection module is aligned with the cylindrical lens (6) of the upper banknote optical detection module.

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