Object detection device

Abstract

To provide an object detecting device that does not affect an object and has less restrictions in terms of operation of a product.SOLUTION: Presence or absence of a second object 24 (foreign matter) that is positioned between a first object 22 and a signal detection portion 16 and is made of a material differing from that of the first object 22 is identified on the basis of a detection signal generated by terahertz waves Wt radiated by black body radiation from the first object 22. It is not necessary to consider influence on an object (product 30) since an electrolytic dissociation radiation, such as X rays, is not applied to the object (product 30) for which an object is detected, and trouble by noise is not given to communication lines and surrounding electrical appliances since terahertz waves Wt subjected to black body radiation have weak energy, such that there are less restrictions in terms of operation of an object detecting device 10B and it becomes advantageous for improvement of convenience.SELECTED DRAWING: Figure 1

Description

[[Technical Field]]

[0001] The present invention relates to an object detection device. [[Background Art]]

[0002] A non-destructive inspection device is known that irradiates an object with X-rays, and determines the shape of the object, the presence or absence of foreign matter, and the like based on detection signals obtained by receiving transmitted waves that have passed through the object or reflected waves reflected by the object with a detector. [[Prior Art Literature]] [[Patent Literature]]

[0003] [[Patent Document 1]] Japanese Unexamined Patent Publication No. 2021-173675 [[Summary of the Invention]] [[Problem to be Solved by the Invention]]

[0004] However, there is a constraint that such a non-destructive inspection device cannot be used when it is undesirable for the object to be affected by X-rays. There are also non-destructive inspection devices that irradiate an object with electromagnetic waves used in radar or the like instead of X-rays, but such electromagnetic wave irradiation devices have the adverse effect of causing noise-induced failures to communication lines and surrounding electrical products, so there are constraints on the operation of non-destructive inspection devices. The present invention has been made in view of such circumstances, and an object of the present invention is to provide an object detection device that has no influence on a target object and has fewer constraints when operating the device. [[Means for Solving the Problem]]

[0005] To achieve the above objective, one embodiment of the present invention is characterized by comprising: a signal detection unit that receives terahertz waves emitted from a first object by blackbody radiation and generates a detection signal; and an object identification unit that identifies the presence or absence of a second object made of a different material from the first object, located between the first object and the signal detection unit, based on the detection signal. [Effects of the Invention]

[0006] According to one embodiment of the present invention, the presence or absence of a second object, which is made of a different material from the first object and is located between the first object and the signal detection unit, is identified based on a detection signal generated from terahertz waves emitted by blackbody radiation from the first object. Since the object being detected is not irradiated with ionizing radiation such as X-rays, there is no need to consider the effects on the object. Furthermore, because the terahertz waves emitted by the blackbody are weak in energy, they do not cause noise interference to communication lines or surrounding electrical products. This results in fewer constraints on the operation of the object detection device and is advantageous in improving convenience. [Brief explanation of the drawing]

[0007] [Figure 1] This is an explanatory diagram showing the configuration of an object detection device according to the first embodiment. [Figure 2] This is a block diagram showing the configuration of an object detection device according to a second embodiment. [Modes for carrying out the invention]

[0008] (First Embodiment) Hereinafter, embodiments of the object detection device of the present invention will be described with reference to the drawings. First, let me explain the terahertz waves used in this invention. Terahertz waves are electromagnetic waves also known as far-infrared frequency range or submillimeter waves, with a frequency band from 100 GHz to 10 THz and a wavelength range from 3 mm to 30 μm. It is known that black bodies emit electromagnetic waves across a wide range of wavelengths (frequencies) through blackbody radiation. Terahertz waves are not only included in the electromagnetic waves emitted by black bodies through blackbody radiation, but also in the electromagnetic waves emitted by the human body, water, and other materials through blackbody radiation. Terahertz waves have the property of penetrating clothing, paper, and synthetic resin materials, but not penetrating metal materials and are reflected by them. Furthermore, terahertz waves emitted from objects by blackbody radiation have extremely weak energy and are unlikely to cause noise-induced interference to electrical products or communication lines. In addition, terahertz waves are non-ionizing radiation, unlike ionizing radiation such as X-rays, and are known to have no effect on the human body or living organisms.

[0009] The object detection device 10B of the first embodiment is used to determine whether or not foreign matter is mixed in with non-metallic products being transported along a transport path. In this embodiment, the non-metallic product is described as a food product such as snacks contained in a bag, but the product can be any non-metallic material that allows terahertz waves Wt to ​​pass through, and is not limited to food products.

[0010] As shown in Figure 1, the object detection device 10B is composed of a signal detection unit 16, a radiation unit 26, an object identification unit 18, and a notification unit 20. The signal detection unit 16 is located above the transport path 28 that transports the product 30. The transport path 28 is composed of, for example, a belt conveyor. The signal detection unit 16 is composed of a detector array 16B in which a plurality of detectors that receive terahertz waves Wt and generate a detection signal are arranged linearly at predetermined intervals, and the detector array 16B is housed and held in an elongated case. Furthermore, when viewed from above, the detector array 16B is positioned to extend in a direction intersecting the transport direction F of the transport path 28, and when viewed from the transport direction F, the detector array 16B extends over the entire width of the transport path 28 perpendicular to the transport direction F.

[0011] The radiating section 26 is composed of a first object 22 made of a liquid or solid that generates terahertz waves W through blackbody radiation. In this embodiment, we will describe the case in which a liquid is used as the first object 22. The radiating section 26 includes a conduit 2602 made of a material that can transmit terahertz waves Wt and contains a liquid, and a heater 2604 for heating the liquid in the conduit 2602. Various conventionally known liquids, such as water and oil, can be used as the liquid. The conduit 2602 is located below the transport path 28 and extends in a direction intersecting the transport direction F of the transport path 28. When viewed from the transport direction F, the conduit 2602 extends across the entire width of the transport path 28 perpendicular to the transport direction F. The conduit 2602 is also parallel to the detector array 16B. Therefore, the first object 22 (liquid) is contained below the transport path 28 and extends in a direction intersecting the transport path 28. The first object 22 (liquid) contained in the conduit 2602 is heated by the heater 2604, causing it to emit terahertz waves Wt as a blackbody over the entire length of the conduit 2602, that is, over the entire width of the transport path 28. Conversely, it is also possible to place the signal detection unit 16 below the transport path 28 and the first object 22 (liquid) above the transport path 28. Furthermore, similar to the second embodiment described later (Figure 2), if a scanning unit 14 that performs scanning using a polygon mirror is provided, a single detector 16A can be used as the signal detection unit 16 instead of the detector array 16B.

[0012] The object identification unit 18 identifies, based on the detection signal, the presence or absence of a foreign object made of a different material from the first object 22 (liquid) located between the first object 22 and the signal detection unit 16, in other words, a second object 24 which is a foreign object mixed into the product 30. Here, the second object 24 can be a metal product, a liquid, a powder, various solids, etc. In the present embodiment, the terahertz wave Wt is emitted from the first object 22 to the product 30 conveyed along the conveyance path 28, and the terahertz wave Wt transmitted through the product 30 is detected by the signal detection unit 16 configured by the detector array 16B. Here, while the product 30 transmits the terahertz wave Wt, the second object 24 (foreign matter), which is a metal product, liquid, powder, or various solid matters mixed into the product 30, does not transmit the terahertz wave Wt, or the transmission amount of the terahertz wave Wt varies depending on the material. Therefore, the object identification unit 18 can identify the presence or absence of the second object 24 based on the detection signal. Furthermore, since the product 30 is conveyed in the conveyance direction F by the conveyance path 28, the signal detection unit 16 generates detection signals over the entire area of the product 30 in the conveyance direction F. Therefore, the object identification unit 18 can identify the presence or absence of foreign matter over the entire area of the product 30 in the conveyance direction F and the entire area in the width direction orthogonal to the conveyance direction F.

[0013] The notification unit 20 is configured to notify that the object identification unit 18 has identified the second object 24. For example, the notification unit 20 may sound a warning alarm using a buzzer or a speaker, utter a warning message, turn on or blink a warning light, or display information indicating that the second object 24 has been identified as text information on a display device such as a liquid crystal display.

[0014] According to the first embodiment, the presence or absence of the second object 24 (foreign matter), which is made of a material different from that of the first object 22 and located between the first object 22 and the signal detection unit 16, is identified based on the detection signal generated from the terahertz wave Wt emitted by blackbody radiation from the first object 22. Therefore, since ionizing radiation such as X-rays is not irradiated onto the target object (product 30) for object detection, there is no need to consider the influence on the target object (product 30). In addition, since the energy of the terahertz wave Wt radiated by the blackbody is weak, it does not cause interference caused by noise to communication lines and surrounding electrical appliances. Therefore, there are few restrictions on the operation of the object detection device 10B, which is advantageous in improving convenience.

[0015] In addition, according to the first embodiment, the notification unit 20 notifies that the object identification unit 18 has identified the second object 24 (foreign matter), so that it is possible to reliably exclude products 30 contaminated with foreign matter by grasping that foreign matter is mixed in products 30 such as food, which is advantageous for improving the safety, reliability and quality of products 30 provided to consumers.

[0016] In addition, according to the first embodiment, a liquid that is easy to handle is used as the first object 22 that blackbody-radiates the terahertz wave Wt, which is advantageous for reducing the cost and simplifying the configuration of the object detection device 10B. It should be noted that, in the first embodiment, the case where the liquid as the first object 22 is accommodated in the pipe line 2602 has been described, but it goes without saying that the liquid may be accommodated in a container with an open top.

[0017] (Second Embodiment) Next, the second embodiment will be described. It should be noted that, in the following embodiments, the same parts and members as those in the first embodiment are denoted by the same reference numerals, the description thereof will be simplified, and different parts will be described with emphasis. The object detection device of the second embodiment is used to determine whether a thermal radiation object such as a human body as a first object carries a second object different from the first object. Examples of the second object include metal products, liquids, powders, various solid substances, and the like. Metal products include, for example, tools, blades, firearms, and the like. Liquids include, for example, toxic and deleterious substances. Powders and solids include, for example, explosives.

[0018] As shown in Figure 2, the object detection device 10A of the second embodiment is configured to include a portable case 12, a scanning unit 14, a signal detection unit 16, an object identification unit 18, and a notification unit 20. The portable case 12 comprises a case body 1202 and an opening 1204 provided in the case body 1202 for receiving terahertz waves Wt. The case body 1202 houses and holds the scanning unit 14, the signal detection unit 16, the object identification unit 18, and the notification unit 20. The scanning unit 14 includes a polygon mirror (not shown), a rotation drive unit, and a oscillation drive unit, and is capable of two-dimensional scanning. The polygon mirror is rotated by a rotation axis extending horizontally, and reflects the terahertz wave Wt that is emitted as a blackbody from the human body, which is the first object 22, and reaches the inside of the portable case 12 through the opening 1204, and guides it to the signal detection unit 16. Furthermore, in order to efficiently guide the terahertz waves Wt reflected by the polygon mirror to the signal detection unit 16, it is optional to provide known optical components such as mirrors or lenses between the aperture and the polygon mirror, or between the polygon mirror and the signal detection unit 16. The rotary drive unit rotates the rotating shaft and is composed of an electric motor. The oscillating drive unit is designed to oscillate the rotation axis in the horizontal direction, and is composed of, for example, a vibration actuator that oscillates the rotation drive unit in the horizontal direction. Conversely, it is also possible to rotate the polygon mirror using a rotation axis extending vertically, and to oscillate the rotation axis horizontally using a oscillating drive unit.

[0019] The signal detection unit 16 receives terahertz waves Wt emitted by blackbody radiation from a first object 22, which is a thermal radiating object such as the human body, and generates a detection signal. In the second embodiment, the signal detection unit 16 is composed of a single detector 16A that receives terahertz waves Wt and generates a detection signal. The object identification unit 18 identifies the presence or absence of a second object 24, which is different from the first object 22 (a heat-emitting object such as a human body), located between the first object 22 and the signal detection unit 16, based on the detection signal. Here, the second object 24, which can be a metal product, liquid, powder, or various solid materials, either does not transmit terahertz waves Wt, or the amount of terahertz waves Wt transmitted varies depending on the material. Therefore, the object identification unit 18 can identify the presence or absence of the second object 24 based on the detection signal. In other words, the object identification unit 18 only needs to be able to identify the presence or absence of the second object 24, and various conventionally known image analysis methods can be used as identification methods by the object identification unit 18, such as the object identification unit 18 identifying the presence or absence of the second object 24 based on the shape of the first object 22 and the shape of the second object 24 as determined based on the detection signal.

[0020] The notification unit 20 notifies that the object identification unit 18 has identified the second object 24, and, as in the first embodiment, uses a buzzer, speaker, warning light, and display device to notify.

[0021] According to the second embodiment, the presence or absence of a second object 24 (metal product, liquid, powder, various solids) made of a different material from the first object 22, located between the first object 22 and the signal detection unit 16, is identified based on a detection signal generated from terahertz waves Wt emitted by blackbody radiation from the first object 22 (a thermal radiating object such as the human body). Therefore, as with the first embodiment, since ionizing radiation such as X-rays is not irradiated onto the object to be detected (thermal radiating object such as the human body), there is no need to consider the effects on the object (thermal radiating object such as the human body), and because the terahertz waves Wt emitted by the blackbody have weak energy, they do not cause noise interference to communication lines or surrounding electrical products, thus there are fewer constraints on operating the object detection device 10A, which is advantageous in improving convenience.

[0022] Furthermore, according to the second embodiment, the notification unit 20 notifies that the object identification unit 18 has identified a second object 24, which is a metal product, liquid, powder, or various solids. For example, in situations where it is necessary to prevent users from bringing in metal products, liquids, powders, or various solids that are subject to restrictions, such as at airports or event venues, it is possible to easily and reliably ascertain whether or not a user is in possession of a metal product. This is advantageous in taking appropriate action against users and improving security.

[0023] Furthermore, according to the second embodiment, the polygon mirror is rotated by a rotation axis extending in the horizontal direction to reflect the terahertz waves Wt emitted from the first object 22 and guide them to the signal detection unit 16, and the rotation axis is oscillated in the horizontal direction by the oscillation drive unit. Therefore, the terahertz waves Wt emitted from the first object 22 can be captured over a rectangular area having vertical height and horizontal width, in other words, a two-dimensional area, and reliably guided to the signal detection unit 16. This is advantageous for reliably identifying the second object 24 by the object identification unit 18 over a two-dimensional area. [Explanation of Symbols]

[0024] 10A, 10B Object Detection Device 12 Portable Cases 1202 Case body 1204 Opening 14 Scanning Unit 16 Signal detection unit 16A Detector 16B Detector Array 18 Object Identification Unit 20 Hochi Department 22 1st object 24 Second object 26 Radiation section 2602 Pipeline 2604 Heater 28 Conveyor path 30 products Wt Terahertz waves F Conveying direction

Claims

1. A signal detection unit that receives terahertz waves emitted by blackbody radiation from a first object which is a liquid heated by a heater and generates a detection signal, An object identification unit identifies the presence or absence of a second object made of a different material from the first object, located between the first object and the signal detection unit, based on the detection signal, on the basis that the second object does not transmit the terahertz waves or that the amount of terahertz wave transmission differs depending on the material. An object detection device characterized by comprising the following features.

2. The object identification unit includes a notification unit that notifies that the object identification unit has identified the second object. The object detection device according to claim 1, characterized in that it is a feature of the present invention.

3. The signal detection unit is provided either above or below the transport path for transporting non-metallic products. The first object is housed above or below the transport path and extends in a direction intersecting the transport path, The aforementioned second object is a foreign substance mixed into the product. The object detection device according to claim 1, characterized in that it is a feature of the present invention.

4. The liquid is contained within a conduit provided above or below the transport path, extending in a direction intersecting the transport path, and made of a material that allows the terahertz waves to pass through. The object detection device according to claim 3, characterized in that it is as described above.

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