JPH10282247A - Metal detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the detection of a metal object such as small fire arms concealed on a person from a remote distance by radiating radio waves toward the person and detecting the difference in the reception levels of reflected waves between the person and the metal body from among the received signals of reflected waves. SOLUTION: Radio wave beams 6 are radiated from a remote distance toward a person 1 by an antenna 7 to detect a metal body 2 such as small fire arms through the use of the difference in reception levels between the metal body 2 and the person 1 contained in reflected waves. For example, if we let the distance between the antenna 7 and the person 1 be R, the width of the radio wave beams 6 be θ, and the diameter of a region that the person 1 is irradiated with the radio wave beams 6 be d, d=2Rtan(θ/2). In the reception level A of the metal body 2 and the person 1, if we let the size of the metal body 2 be D and a multiplier of proportionality be K, A=K(D/d)2 in the case d>D and A=K in the case d<=D. As the difference in reception level between the metal body 2 and the person 1 can be maximized by appropriately selecting the width θof the radio wave beams, it is possible to detect the metal body 2 separately from the person 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal detecting device configured to detect a so-called metal object such as a firearm, a weapon, or the like, which is concealed by a human, using radio waves.

[0002]

2. Description of the Related Art Conventionally, in airports and the like, in order to detect metal objects such as firearms and weapons hidden by humans, portal-type metal detection devices using magnetic sensors and portable metal detection devices have been introduced. Was. For this system, for example,
"METAL DETEC" of HEIMANN, Germany
TOR GATE: MDT8900 ", which is widely known in catalogs and the like.

In recent years, crimes using firearms and the like have increased, and smuggling of firearms and the like used for such crimes has also increased sharply. These problems have become one of the major social problems, and security measures to prevent them beforehand are desired. However, it is difficult to address the above-mentioned problems in various situations with a conventional metal detection device. For example, in the case of a gate-type metal detection device, metal cannot be detected unless a human passes through the gate, and in the case of a portable metal detection device, it cannot be detected unless the detection device is brought close to a human. . That is, if it is not possible to detect a metal object concealed by a human from a distant distance, there is a problem that a preventive measure cannot be taken against sudden firearm crime or the like. Therefore, a metal detection device capable of detecting a metal body such as a firearm from a long distance is proposed.

FIG. 5 is a diagram showing the operation of a conventional metal detector. In FIG. 5, reference numeral 1 denotes a human, 2 denotes a metal body such as a firearm,
Is a traveling direction of the person 1, 4 is a magnetic detection sensor, and 5 is a display. The conventional metal detection device is configured as described above. For example, when a person 1 has a metal body 2 of firearms and dives under a portal-type magnetic detection sensor 4 in a traveling direction 3, the magnetic detection sensor 4 becomes It is formed of a wire of a good conductor of electricity wound on a coil, and detects a change in magnetism caused by a metal object and notifies the indicator 5 of the change.

[0005]

In the metal detecting device constructed as described above, it is difficult to detect a metal object such as a firearm concealed by a human on a general road or a public place from a remote distance. There was a problem that there was.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and an object of the present invention is to detect a metal object such as a firearm hidden by a person from a remote distance.

[0007]

SUMMARY OF THE INVENTION A metal detector according to the present invention radiates radio waves to humans by utilizing the fact that there is a difference in the radio wave reception level between a human and a metal body, and emits radio waves to humans. An antenna that receives a reflected wave, a transceiver connected to the antenna, and a reception signal obtained by the transceiver, detects a difference between reception levels of reflected waves of a human body and a metal body, and detects the reception level of the reception level. A signal processor for outputting a signal corresponding to the difference, a contrast image former for forming a contrast image according to the output of the signal processor, and an image pickup for obtaining an image in a transmission beam direction radiated from the antenna An image synthesizer for synthesizing images of the contrast image forming device and the image pickup device, and an image display for displaying an output of the image synthesizing device.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. FIG. 1 is a conceptual diagram showing Embodiment 1 of the present invention. In FIG. 1, reference numeral 1 denotes a human being, 2 denotes a metal body of firearms, and 6 denotes a radio beam radiated or reflected to the human 1. , 7 are antennas for radiating the radio wave beam 6 and receiving the reflected wave thereof, 8 is a transceiver connected to the antenna 7, and 9 is the human 1 and the firearm out of the reception signals obtained by the transceiver. A signal processor that detects a difference in the reception level of the metallic body 2 and outputs a signal corresponding to the difference in the reception level, and a contrast 10 that forms a contrast image according to the signal level from the output of the signal processor. An image forming device 11 is an image capturing device that captures an image in the same direction as the radio wave beam 6 transmitted to a human, and a component 12 combines the output of the contrast image forming device 10 and the output of the image capturing device 11. Image synthesizer 7 is an image display device for displaying the image synthesizer output.

In the metal detecting device constructed as described above, the radio beam 6
Is emitted to the human 1, and the metal body 2 of firearms can be detected by utilizing the difference in the reception level between the metal 2 and the human 1 included in the reflected wave. For example, the antenna 7
Assuming that the distance between R and the human 1 is R, the width of the transmission beam radiated from the antenna 7 is θ, and the diameter of the range of the human 1 irradiated by the radio wave beam 6 is d, d = 2Rtan (θ / 2). Here, assuming that the size of the metal object 2 is D, the reception level A of the metal object 2 and the human 1 is proportional to the ratio of the metal object 2 to the human 1 in the range where radio waves are irradiated. Multiplier K
When simplification is made using A, K = A (D / d) 2 (when d> D) or A = K (when d ≦ D). Also,
Humans have a lower reception level due to the reflection of radio waves than metal bodies, and this is equivalent to the case where the ratio of the metal bodies 2 to the human 1 becomes the smallest in the range where the radio waves are irradiated. FIG. 2 shows D = 12 cm as an example of a metal body 2 for firearms.
FIG. 9 is a diagram showing a relationship between the transmission beam width θ and the reception level A when the metal body of FIG.
14 is the sum of the reflection levels from the metal body 2 and the person 1, 15 is the reflection level from the person 1, and 16 is the difference between the reception levels of the metal body 2 and the person 1. Here, in the case of the above operation, if the radio wave beam width θ is within 1.2 degrees, the difference in reception level can be maximized, and the metal body 2 and the human 1 can be distinguished and detected. can do.

FIGS. 3 and 4 show examples of display on the image display 13 of the first embodiment.
7 is a display screen of an image display, 1 is a human, 2 is a metal body, 1
9 is a contrast image. 3 and 4, the size of the circle of the contrast image 19 corresponds to the transmission beam width, and indicates that the inside is the irradiation range. The contrast image 19 receives a reflected wave from the irradiation range, and displays the level of the reception level with the density in the contrast image. For example, the color is set to be dark when a reflection object with a high reception level such as a metal object is viewed, and to be light when a reflection object with a low reception level such as a human body is viewed.
FIG. 3 shows a case where the irradiation range of the transmission beam hardly covers the metal body 2 hidden by a person.
Means that the irradiation range of the transmission beam is a metal object 2
Shows the case where they overlap. In FIG. 4, it can be seen that the density of the contrast image 19 is high, and the metal object 2 having large reflection exists there. That is, it is determined whether or not the human body 1 is hiding the metal body 2 having a large reception level, while checking the display screen 17 by manually operating the antenna 7 or by using another scanning means such as a gimbal or the like. The observation can be performed by observing whether or not a change appears to increase the density of the contrast image.

[0011]

According to the present invention, it is possible to detect a metal object concealed by a person from a distant place by utilizing the difference between the reflection levels of the metal object and the person using radio waves.

[Brief description of the drawings]

FIG. 1 is a first embodiment of a metal detection device according to the present invention.
FIG.

FIG. 2 is a first embodiment of a metal detection device according to the present invention;
FIG. 4 is a diagram showing a difference in reception level between a metal object and a person in the embodiment.

FIG. 3 is a first embodiment of a metal detection device according to the present invention;
3 is a diagram showing an example of a display screen.

FIG. 4 is a first embodiment of a metal detection device according to the present invention;
3 is a diagram showing an example of a display screen.

FIG. 5 is an operation diagram showing an embodiment of a conventional metal detection device.

[Explanation of symbols]

Reference Signs List 1 human, 2 metal body, 3 traveling direction, 4 magnetic detection sensor, 5 display, 6 radio beam, 7 antenna, 8
Transceiver, 9 signal processor, 10 contrast imager, 11 image pickup device, 12 image synthesizer, 13
Image display, 14 Sum of reception level of metal body and reception level of human, 15 Difference of reception level of human, 16 Difference of reception level, 17 Display screen, 18 Contrast image.

Claims (1)

[Claims] 1. A metal detecting device for detecting a metal body such as a firearm, wherein the antenna radiates radio waves to a human and receives a reflected wave thereof, a transceiver connected to the antenna, and the transceiver. A signal processor that detects a difference in the reception level between the reflection from the human body and the reflection from a metal object possessed by a human from among the received signals, and the reception level of the reception level detected by the signal processor. A contrast image former for forming an image having a contrast corresponding to the difference, and a direction of a transmission beam transmitted from the antenna to a human having a viewing angle of 1.2 times or more of a transmission beam width of the antenna. An image capturing apparatus that captures an image with visible light or infrared light by aligning the optical axis with the optical axis, and combining the output from the contrast image forming device with the output from the image capturing apparatus. A metal detecting device comprising: an image synthesizer to be formed; and an image display for displaying an output of the image synthesizer.