Identification marker, method of use thereof, and safety monitoring system

Abstract

To provide an identification marker capable of recognizing a no-entry area in a work site stably regardless of a position of a camera, the identification marker being installed when identifying the no-entry area.SOLUTION: In a safety monitoring system 1000, when monitoring whether or not a person 500 enters a monitoring target area 400 by means of an imaging device 200, an identification marker 100 is disposed in each corner of the monitoring target area 400. The identification marker 100 consists of a spherical member having a bottomed hole of which the opening diameter is 50 mm or more. A diameter of the spherical member is 250 mm or more. The identification marker 100 further includes a screw part of which the first end is fixed to a bottom of the bottomed hole and the second end protrudes from the bottomed hole. The spherical member is colored in violet, yellow or green, and a plurality of circular or polygonal graphics provided at position in point symmetry to a center of the spherical member is indicated on a surface of the spherical member.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] An embodiment of the present invention relates to an identification marker, a method for using the same, and a safety monitoring system, and more particularly to an identification marker for identifying a specific area at a work site where construction work such as building construction or civil engineering work is carried out. [Background technology]

[0002] Conventionally, as a technology for recognizing a specific position at a work site, a technology has been known in which an index is placed at a specific target position as a landmark and the specific position is detected based on the position of the index. For example, Patent Document 1 discloses a technology in which an identification marker such as a two-dimensional code is placed on the floor or the like of the work site, the identification marker is extracted from an image obtained by photographing the floor of the work site with a camera placed at an elevated position, and the specific position is detected based on the extracted identification marker.

[0003] Furthermore, Patent Document 2 discloses a technology in which endpoint markers (road cones) are placed around a no-entry area such as a work site, and the endpoint markers are extracted from an image obtained by photographing the work site with a camera placed at an elevated position using image processing, and the location of the no-entry area is identified based on the extracted endpoint markers. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-078569 [Patent Document 2] Japanese Patent Application Publication No. 2019-016836 Summary of the Invention [Problem to be solved by the invention]

[0005] When a planar identification marker such as a two-dimensional code is used as an identification marker as in the above-described conventional technology, the identification marker may not be recognized correctly depending on the camera's angle of view due to the influence of tilt or the influence of sunlight or lighting reflection. Furthermore, when a planar identification marker is placed on the floor, there is a problem that it may be easily blocked from the camera by work objects placed on it depending on the installation location. Furthermore, when a road cone is used as an identification marker, the accuracy of shape recognition may decrease if the road cone is photographed from an angle close to directly above, and it may not be recognized as a road cone.

[0006] An object of one embodiment of the present invention is to provide an identification marker that can be stably recognized regardless of the position of an imaging device. Another object of one embodiment of the present invention is to provide a safety monitoring system that uses an identification marker that can be stably recognized regardless of the position of an imaging device. [Means for solving the problem]

[0007] In one embodiment of the present invention, the identification marker is comprised of a spherical member having a bottomed hole with an opening diameter of 50 mm or more. The diameter of the spherical member may be 250 mm or more. The identification marker may further include a threaded portion having a first end fixed to the bottom of the bottomed hole and a second end protruding from the bottomed hole.

[0008] The identification marker may further have an attachment portion configured to be able to fit into the bottomed hole. In this case, the spherical member may have a screw hole formed at the bottom of the bottomed hole. The attachment portion may include a first screw portion that screws into the screw hole and a second screw portion that is formed on a second surface opposite to the first surface on which the first screw portion is formed. The first screw portion and the second screw portion may have different nominal diameters.

[0009] The spherical member may be colored purple, yellow, or green. A plurality of circular or polygonal figures may be marked on the surface of the spherical member, the circles or polygons being positioned point-symmetrically with respect to the center of the spherical member.

[0010] In one embodiment of the present invention, the identification marker is used in combination with a road cone by fitting the bottomed hole of the above-described identification marker onto the tip of the road cone.

[0011] In a method of using the identification marker in one embodiment of the present invention, the threaded portion of the above-described identification marker is attached to a clamp, and the identification marker is used in combination with the clamp.

[0012] A method of using the identification marker in one embodiment of the present invention is to attach the second screw portion of the above-mentioned identification marker to a tripod or a clamp, thereby attaching the identification marker to the tripod Or, it is used in combination with the clamp.

[0013] A safety monitoring system in one embodiment of the present invention comprises an imaging device that captures images of a specified space, a monitoring device that analyzes the captured images transmitted from the imaging device, and an identification marker placed within the space, wherein the identification marker is composed of a spherical member having a bottomed hole with an opening diameter of 50 mm or more, and the monitoring device identifies the area to be monitored by extracting the identification marker from the captured images obtained from the imaging device.

[0014] The monitoring device may detect whether or not a person is present in the area to be monitored or in the vicinity of the area to be monitored, based on the captured image.

[0015] When the monitoring device determines that the person is present in the monitored area, it may transmit an instruction signal to other information processing devices to notify them that a person has entered the monitored area.

[0016] The safety monitoring system may further include an alarm device that issues an alarm within the space. In this case, when the monitoring device determines that the person is present in the vicinity of the monitored area, the monitoring device may transmit an instruction signal to the alarm device to issue the alarm. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a schematic diagram showing the configuration of a safety monitoring system according to an embodiment of the present invention; [Figure 2] 1 is a diagram showing the configuration of an identification marker in one embodiment of the present invention. FIG. [Figure 3] 1 is a diagram showing the configuration of an identification marker in one embodiment of the present invention. FIG. [Figure 4] FIG. 10 is a schematic diagram showing the configuration of a safety monitoring system according to a modified example of an embodiment of the present invention. [Figure 5] 1 is a block diagram showing the configuration of a safety monitoring system according to an embodiment of the present invention. [Figure 6] FIG. 4 is a flowchart illustrating the operation of the monitoring device according to the embodiment of the present invention. [Figure 7] 10A and 10B are diagrams illustrating the configuration of an identification marker according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention can be embodied in various forms without departing from the spirit of the present invention, and should not be construed as being limited to the description of the embodiments exemplified below. To clarify the explanation, the drawings may show the width, thickness, size, shape, etc. of each part schematically compared to the actual form, but these are merely examples and are not intended to limit the interpretation of the present invention. In this specification and each drawing, elements having the same functions as those described with reference to the previous drawings may be assigned the same reference numerals, and redundant explanations may be omitted.

[0019] In this specification, for the sake of convenience, the terms "upper", "above", or "top", or "lower", "below", or "lower" may be used to describe the relative positional relationship between elements or parts. For example, when describing an object, the direction in which gravity acts may be referred to as "down" and the opposite direction as "up", based on the way the object is normally used.

[0020] (First embodiment) [Safety monitoring system configuration] 1 is a schematic diagram showing the configuration of a safety monitoring system 1000 according to one embodiment of the present invention. The safety monitoring system 1000 of this embodiment includes at least an identification marker 100, an imaging device 200, and a monitoring device 300.

[0021] The safety monitoring system 1000 is a system for monitoring a specific area at a work site such as a construction site or civil engineering work site. The specific area (hereinafter referred to as the "monitored area") is, for example, a non-safe area where safety cannot be ensured, and in this embodiment, it is a no-entry area. In FIG. 1, an opening formed in the soil is set as the monitored area 400, and whether or not a person 500 has entered the monitored area 400 is monitored. However, the monitored area 400 is not limited to this example, and can be set arbitrarily depending on the purpose of monitoring.

[0022] 1, a plurality of identification markers 100 are placed around the area to be monitored 400. In the safety monitoring system 1000 of this embodiment, an identification marker 100 is placed at each of the four corners of the opening that is the area to be monitored 400. Here, the identification marker 100 is installed on the top of a traffic cone 150, and the traffic cone 150 is placed at each corner of the area to be monitored 400.

[0023] The imaging device 200 functions as a surveillance camera that captures images of the work site from a high position. That is, the imaging device 200 captures an overhead image of the work site. It is preferable that the imaging device 200 captures images in a video format, but if there are no moving objects such as people, the imaging device 200 may capture still images in a still image format that captures still images intermittently.

[0024] 1 illustrates only one imaging device 200, multiple imaging devices 200 may be placed at a work site to be monitored. The imaging device 200 may be placed at a fixed position so as to be able to take fixed-point images, or may be placed at a movable position. For example, a crane camera may be used as the imaging device 200, or the imaging device 200 may be mounted on a drone so as to take aerial images while moving in the sky.

[0025] The monitoring device 300 can receive captured images transmitted from the imaging device 200 and perform image analysis on the acquired captured images. An information processing device having an image processing function can be used as the monitoring device 300. In this embodiment, the imaging device 200 and the monitoring device 300 communicate with each other wirelessly, but the present invention is not limited to this example, and the imaging device 200 and the monitoring device 300 may be connected by wire.

[0026] [Identification marker configuration] Fig. 2 is a diagram showing the configuration of an identification marker 100 according to one embodiment of the present invention. Specifically, Fig. 2(A) is a side view of the identification marker 100, and Fig. 2(B) is a rear view of the identification marker 100. However, for ease of explanation, coloring of the identification marker 100 is omitted in Fig. 2.

[0027] As shown in Figures 2(A) and 2(B), the identification marker 100 of this embodiment has a marker body 110 made of a spherical member. That is, when viewed from above, the appearance of the identification marker 100 is a sphere no matter what direction it is viewed from. In this embodiment, when the diameter of the marker body 110 is X1, X1 ≥ 250 mm (preferably X1 ≥ 300 mm). However, this is not a limitation, and the diameter of the marker body 110 may be less than 250 mm.

[0028] The marker body 110 is provided with a bottomed hole 120. As shown in FIG. 1, the bottomed hole 120 is a hole used when attaching the identification marker 100 to the top of the road cone 150, and is desirably large enough to allow the top of the road cone 150 to be inserted therein. As shown in FIG. 2(B), when the opening diameter (i.e., the diameter of the open end) of the bottomed hole 120 is X2, X2 ≧ 50 mm (preferably X2 ≧ 75 mm) and when the depth of the bottomed hole 120 is X3, X3 ≧ 40 mm (preferably X3 ≧ 50 mm). However, this is not a limitation, and the opening diameter and depth of the bottomed hole 120 may be less than the above numerical ranges as long as they are within a range that allows attachment to the top of the road cone 150.

[0029] As shown in FIG. 2(A), a threaded portion 130 is provided in the center of the bottom 121 of the bottomed hole 120. Specifically, the threaded portion 130 is disposed so that a first end is fixed to the bottom 121 and a second end protrudes from the bottomed hole 120. When the difference between the depth of the bottomed hole 120 and the length of the threaded portion 130 is X4, X4≧10 mm (preferably, X2≧20 mm). That is, the total length of the threaded portion 130 is 50 mm or more (preferably, 70 mm or more). However, this is not a limitation, and the length of the threaded portion 130 may be less than 50 mm.

[0030] As described above, the identification marker 100 of this embodiment has high identifiability in all directions because the marker body 110 is made of a spherical member. Therefore, this embodiment can provide an identification marker 100 that can be stably recognized regardless of the position of the imaging device 200. Furthermore, in the safety monitoring system 1000 shown in FIG. 1 , the monitoring device 300 can stably recognize the identification marker 100 regardless of the relative positional relationship between the identification marker 100 and the imaging device 200. In addition, coloring the marker body 110 can further improve the identifiability of the identification marker 100.

[0031] Fig. 3 is a diagram showing the configuration of an identification marker 100 according to one embodiment of the present invention. Specifically, Fig. 3(A) is a side view of the identification marker 100 in which the marker body 10 is colored in two colors, and Fig. 3(B) is a side view of the identification marker 100 in which the marker body 10 is colored and also has a pattern.

[0032] FIG. 3(A) shows an example in which the marker body 110 is divided into two regions and colored. In this embodiment, the colored region 111 on the right side of the marker body 110 is colored purple, and the colored region 112 on the left side of the marker body 110 is colored yellow. However, the number of divided regions is not limited to two, and more regions may be divided and colored in two or more colors. There are no particular restrictions on the colors used for coloring, but using colors that are not often used in work sites is preferable because it increases the ability to be distinguished. For example, purple, yellow, or green are suitable. Furthermore, it is preferable to apply a matte finish to the marker body 110 to prevent reflection from sunlight.

[0033] 1, each identification marker 100 is arranged so that the purple colored area 111 is located on the side closer to the monitored area 400. This allows the process of identifying the monitored area 400 to be performed more efficiently.

[0034] 3(B), the marker body 110 is divided into two regions and colored as in FIG. 3(A), and then a polygonal figure 113 is marked on the two regions. The figure 113 is preferably colored differently from the colored regions 111 and 112. In this embodiment, an example is shown in which the figure 113 is colored green.

[0035] A plurality of figures 113 are provided on the surface of the marker body 110, which is made of a spherical member, at positions point-symmetrical with respect to the center of the marker body 110. For example, a plurality of figures 113 may be printed at equal intervals on the surface of the marker body 110. By arranging a plurality of figures 113 on the surface of the marker body 110, a pattern can be applied to the marker body 110. Note that while FIG. 3(B) shows an example in which the figure 113 is a hexagon, it may be another polygon, a circle, or an ellipse.

[0036] The identification marker 100 of this embodiment described above is intended to be used in combination with a road cone 150, as shown in Fig. 1. Specifically, the identification marker 100 is attached to the top of the road cone 150 by fitting the bottomed hole 120 into the top of the road cone 150. To achieve this type of use, the identification marker 100 shown in Fig. 2 has a marker body 110 provided with a bottomed hole 120 of a size that allows it to be fitted into the road cone 150.

[0037] The identification marker 100 of this embodiment can also be used in combination with a clamp using the screw portion 130. Specifically, the identification marker 100 can be fixed to a pipe or the like by fixing the identification marker 100 to a clamp using the screw portion 130 and connecting the clamp to the pipe or the like.

[0038] Fig. 4 is a schematic diagram showing the configuration of a safety monitoring system 1000a in a modified example of one embodiment of the present invention. In the example shown in Fig. 4, a no-entry area is set as a monitored area, and intrusion prevention equipment 450 is placed in front of the monitored area. In this embodiment, the intrusion prevention equipment 450 includes two posts 451, a rope 452 stretched across the two posts 451, and a sign 453 attached to the rope 452, but is not limited to this example.

[0039] As shown in FIG. 4, an identification marker 100 is fixed to a support 451 via a clamp 160. Here, an example in which the identification marker 100 is colored only purple is shown, but as shown in FIG. 3(A) or 3(B), the identification marker 100 may be colored in two or more colors or may have a pattern. In the example shown in FIG. 4, an identification marker 100 combined with a traffic cone 150 is placed in front of the intrusion prevention equipment 450. As described above, by placing a plurality of identification markers 100 around the intrusion prevention equipment 450, the area to be monitored can be efficiently identified from the captured image acquired by the imaging device 200.

[0040] 2 and 3 show an example in which the threaded portion 130 is provided on the marker body 110, but this is not limiting and the threaded portion 130 may be omitted. For example, if the road cone 150 to be attached does not have a hole at the top, the bottomed hole 120 cannot be fitted into the top of the road cone 150 if the threaded portion 130 is provided. To address such a case, the marker body 110 may be configured without the threaded portion 130.

[0041] Next, the imaging device 200 and the monitoring device 300 that constitute the safety monitoring system 1000 of this embodiment will be described.

[0042] Fig. 5 is a block diagram showing the configuration of a safety monitoring system 1000 according to one embodiment of the present invention. Specifically, Fig. 5 illustrates an imaging device 200 and a monitoring device 300 as elements of the safety monitoring system 1000 that are involved in image processing.

[0043] The imaging device 200 and the monitoring device 300 are connected to a network NW such as the Internet, a communication line, etc. In other words, the safety monitoring system 1000 is a client-server system configured with the imaging device 200 functioning as a client and the monitoring device 300, which is an information processing device functioning as a server.

[0044] The imaging device 200 is, for example, a camera installed in a position that allows a bird's-eye view of the work site. The imaging device 200 can communicate with the monitoring device 300 by connecting to a network NW. In this embodiment, the imaging device 200 is connected to the network NW by wireless communication, but may also be connected by wired communication.

[0045] The monitoring device 300 is an information processing device that receives captured images transmitted from the imaging device 200 and performs various image analyses on the captured images. The monitoring device 300 monitors whether or not a person is approaching or entering the monitored area 400 based on the image analysis. The information processing related to the monitoring function performed by the monitoring device 300 is realized by executing a program recorded in a storage device included in the monitoring device 300, a recording medium readable by the monitoring device 300, or a database to which the monitoring device 300 can connect via the network NW. In FIG. 5, the monitoring device 300 is illustrated as a single information processing device, but it may be composed of multiple information processing devices.

[0046] [Configuration of imaging device] 5, the imaging device 200 of this embodiment includes a control unit 210, an imaging unit 220, and a communication unit 230. However, the imaging device 200 is not limited to this example and may include other elements.

[0047] The control unit 210 includes a processor (arithmetic processing device) such as a CPU (Central Processing Unit) and a storage device such as a RAM. The control unit 210 controls the imaging unit 220 and the communication unit 230. In this embodiment, the control unit 210 controls the imaging unit 220 continuously or intermittently to acquire captured images. The control unit 210 can also control the imaging unit 220 based on control information transmitted from the monitoring device 300.

[0048] The imaging unit 220 captures images at an angle of view that includes the entire work site (or a part of it) and generates a captured image of the work site captured from a high place. The imaging unit 220 can be, for example, a camera including a solid-state imaging element such as a CCD (Charge-Coupled Device) image sensor or a CMOS (Complementary MOS) image sensor. The imaging unit 220 may capture images continuously in a moving image format or intermittently in a still image format. The imaging unit 220 may also be equipped with a depth sensor. By providing the imaging unit 220 with a depth sensor, it is possible to obtain distance information from the imaging device 200 to the subject.

[0049] The communication unit 230 is a wireless communication module that connects to the network NW under the control of the control unit 210 and transmits captured images to the monitoring device 300 connected to the network NW. The communication unit 230 may have a function of receiving control information transmitted from the monitoring device 300. Note that although a wireless communication module has been exemplified as the communication unit 230 in this embodiment, it may also be a wired communication module.

[0050] [Configuration of monitoring device] The monitoring device 300 of this embodiment includes a control unit 310, a storage unit 320, a notification unit 330, and a communication unit 340. However, the monitoring device 300 is not limited to this example, and may include other elements, or the notification unit 330 may be omitted.

[0051] The control unit 310 includes an arithmetic processing circuit (control device) such as a CPU and a storage device such as a RAM. The control unit 310 executes programs stored in the storage unit 320 using the CPU, causing the monitoring device 300 to realize various functions related to the monitoring process. Signals output from each element of the monitoring device 300 are used by the various functions realized in the monitoring device 300. Specific functions of the control unit 310 will be described later.

[0052] The storage unit 320 is a recording device (recording medium) that can permanently hold information and rewrite information, such as a nonvolatile memory or a hard disk drive. The storage unit 320 stores programs and information such as parameters required to execute the programs. For example, a program (monitoring program) related to the monitoring function described above is stored in the storage unit 320. The storage unit 320 also has a database unit (DB unit) 321 that stores various information (e.g., captured images) received from other devices (e.g., the imaging device 200) via the network NW.

[0053] The alarm unit 330 has a function of executing instructions to issue a warning or a caution in accordance with instructions from the control unit 310. Specifically, when the monitoring function described below determines that a person 500 (e.g., a worker) has approached the monitored area 400, the alarm unit 330 can transmit an instruction signal to an alarm device (not shown) arranged at the work site to issue a warning to the person 500. In this case, the warning may be a sound such as a warning tone, or a voice such as "Please be careful as it is dangerous."

[0054] Furthermore, when the monitoring function determines that the person 500 is present in the monitored area 400, the notification unit 330 can transmit an instruction signal to an information processing device (not shown) managed by the site manager to notify the person 500 of this. The information processing device managed by the site manager may be, for example, a laptop computer, a tablet terminal, a mobile terminal such as a smartphone, etc. This allows the site manager to take appropriate action against the person 500 entering the monitored area. Note that, although an example has been shown in which the notification unit 330 notifies the site manager of the entry of the person 500, instead of or in addition to this, the notification unit 330 may transmit an instruction signal to the alarm device described above to issue an alarm to the person 500.

[0055] The communication unit 340 is a wireless communication module that connects to the network NW under the control of the control unit 310, receives captured images from the imaging device 200 connected to the network NW, and transmits instruction signals to other devices such as the imaging device 200, an alarm device, and other information processing devices (for example, information processing devices managed by a site manager). The communication unit 340 may have a function of receiving control information and instruction signals transmitted from other information processing devices. Note that, although a wireless communication module has been exemplified as the communication unit 340 in this embodiment, a wired communication module may also be used.

[0056] The monitoring device 300 described above executes image analysis processing under the control of the control unit 310. The control unit 310 includes, as functional blocks, an area identification unit 311, a person detection unit 312, and a determination unit 313. Each block is realized by the control unit 310 executing a monitoring program read from the storage unit 320.

[0057] The area identification unit 311 extracts the identification marker 100 (see FIG. 1) from the captured image acquired from the imaging device 200, and identifies the position of the monitored area 400 (here, the opening) based on the position of the identification marker 100. The position of the identification marker 100 can be identified by performing image analysis processing on the captured image in accordance with a known algorithm (for example, pattern matching technology, coordinate detection technology, etc.).

[0058] The person detection unit 312 detects a person 500 (see FIG. 1) from a captured image acquired from the imaging device 200. The position of the person 500 can be identified by performing image analysis processing on the captured image in accordance with a known algorithm (for example, a pattern matching technique or a frame difference detection technique).

[0059] The determination unit 313 compares the position of the area to be monitored 400 identified by the area identification unit 311 with the position of the person 500 detected by the person detection unit 312, and determines the relative positional relationship between the area to be monitored 400 and the person 500. Specifically, the determination unit 313 determines the position of the area to be monitored 400, that is, whether or not the person 500 exists within a rectangular area formed by connecting the positions of the identification markers 100 with lines, or whether or not the person 500 exists in the periphery of the rectangular area.

[0060] When the determination unit 313 determines that the person 500 is present in the monitored area 400, it instructs the notification unit 330 to generate an instruction signal to notify the site manager that a person has entered the monitored area 400. Furthermore, when the determination unit 313 determines that the person 500 is present in the periphery of the monitored area 400, it instructs the notification unit 330 to generate an instruction signal to issue an alarm.

[0061] [Monitoring process flow] The safety monitoring system 1000 of this embodiment monitors unsafe areas such as no-entry areas in a work site and executes monitoring processing to ensure the safety of people. The flow of the monitoring processing will be described below.

[0062] Fig. 6 is a flowchart showing the operation of monitoring device 300 in one embodiment of the present invention. In this embodiment, the processing of each step shown in Fig. 6 is executed by control unit 310 of monitoring device 300. That is, control unit 310 reads and executes a monitoring program stored in storage unit 320, thereby realizing each process shown in Fig. 6.

[0063] The control unit 310 executes the monitoring program to sequentially acquire captured images from the imaging device 200 and executes an analysis process for the acquired captured images. When the analysis process is executed, the area identification unit 311 determines whether or not the captured image includes the identification marker 100 (step S101).

[0064] If the determination result in step S101 is YES, the area identification unit 311 extracts the identification marker 100 from the captured image to identify the monitoring target area 400 (step S102). Specifically, the area identification unit 311 calculates the position coordinates of the extracted identification marker 100, and identifies the area identified by the calculated position coordinates as the monitoring target area 400.

[0065] The identification marker 100 may be extracted based on a known algorithm, such as a technique like pattern matching. The position coordinates of the identification marker 100 can be calculated by correcting the two-dimensional coordinates obtained from the captured image according to the angle of view of the imaging device 200, in accordance with a known algorithm (such as a marker detection algorithm used in ARToolKit).

[0066] If the determination result in step S101 is NO, control unit 310 returns the control to step S101 again.

[0067] Once the monitoring target area 400 has been identified, the person detection unit 312 then determines whether or not the captured image includes a person 500 (step S103). Specifically, the person detection unit 312 detects the presence or absence of a person by performing pattern matching on the captured image or detecting frame differences between a plurality of captured images.

[0068] If the determination result in step S103 is YES, the person detection unit 312 calculates the position coordinates of the person 500 from the captured image to identify the position of the person 500 (step S104). The position coordinates of the person 500 can be calculated by correcting the two-dimensional coordinates obtained from the captured image according to the angle of view of the imaging device 200, according to a known algorithm.

[0069] If the determination result in step S103 is NO, control unit 310 returns the control to step S101 again.

[0070] Once the person 500 is identified, the determination unit 313 then determines whether the person 500 is located inside the monitoring area (step S105). Specifically, the determination unit 313 compares the position coordinates of the monitoring area 400 identified in step S102 with the position coordinates of the person 500 identified in step S104, and determines whether the person 500 is located inside or outside the monitoring area 400.

[0071] If the determination result in step S105 is YES, the notification unit 330 generates an instruction signal to notify that the person 500 has entered the monitored area 400, and transmits the signal to the information processing device managed by the site manager (step S106). Upon receiving the instruction signal from the notification unit 330, the information processing device of the site manager can display on a display screen that a person has entered the monitored area 400, or can emit an alarm to that effect. This allows the site manager to quickly take action against the person 500 in the monitored area 400.

[0072] On the other hand, if the determination result in step S105 is NO, the alarm unit 330 generates an instruction signal to notify that the person 500 is present in the vicinity of the monitored area 400, and transmits the signal to an alarm device or the like arranged at the work site (step S107). Upon receiving the instruction signal from the alarm unit 330, the alarm device or the like issues an alarm (an alarm sound or a warning voice) to the person 500 present in the vicinity of the monitored area 400. This makes it possible to appropriately call the attention of the person 500 present in the vicinity of the monitored area 400.

[0073] As described above, according to this embodiment, in the safety monitoring system 1000 that monitors a predetermined space such as a work site, by using the identification marker 100 configured with a spherical member, it is possible to stably recognize the identification marker 100 regardless of the position of the imaging device 200. This makes it possible to realize a safety monitoring system that can stably recognize the identification marker 100 regardless of the relative positional relationship between the identification marker 100 and the imaging device 200.

[0074] (Second embodiment) In this embodiment, an identification marker 100a having a different structure from that of the first embodiment will be described. Specifically, the identification marker 100a of this embodiment has an attachment part 140 that is attached to a marker body 110a. In this embodiment, the same elements as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0075] Fig. 7 is a diagram showing the configuration of an identification marker 100a according to another embodiment of the present invention. Specifically, Fig. 7 is an exploded side view of the identification marker 100a. As shown in Fig. 7, the identification marker 100a has an attachment portion 140. The attachment portion 140 includes a first screw portion 141 and a second screw portion 142.

[0076] The first screw portion 141 is provided on the first surface 140a facing the marker body 110a. The first screw portion 141 is threaded into a screw hole 116 provided in the center of the bottom 121a of the bottomed hole 120a. That is, the nominal diameter of the first screw portion 141 and the nominal diameter of the screw hole 116 match. Furthermore, the length of the first screw portion 141 and the length (depth) of the screw hole 116 also match.

[0077] The second screw portion 142 is provided on a second surface 140b opposite to the first surface 140a facing the marker body 110a. In this embodiment, the nominal diameter of the second screw portion 142 is smaller than the nominal diameter of the first screw portion 141. However, this is not limited to this example, and the nominal diameter of the second screw portion 142 may be larger than the nominal diameter of the first screw portion 141, or may be the same as the nominal diameter of the first screw portion 141.

[0078] In this embodiment, the nominal diameter of the second screw portion 142 can be changed as appropriate depending on the object to which the identification marker 100a is to be fixed. For example, when attaching the identification marker 100a to a tripod or a small clamp, the nominal diameter of the second screw portion 142 can be set to match the nominal diameter of the screw hole of the tripod or small clamp. In this case, multiple types of attachment portions 140 having second screw portions 142 with different nominal diameters can be prepared, and the attachment portion 140 can be replaced depending on the object to which the identification marker 100a is to be fixed.

[0079] 7, the attachment part 140 has the same outer shape as the inner wall of the bottomed hole 120a so that it can close the bottomed hole 120a. In other words, when the attachment part 140 is attached to the marker body 110a, the identification marker 100a becomes substantially spherical. However, this is not limited to this example, and the shape of the attachment part 140 can be any shape as long as it fits inside the bottomed hole 120a.

[0080] When the attachment part 140 is not attached to the identification marker 100a of this embodiment, there is no part protruding inside the bottomed hole 120a. Therefore, when it is assumed that the identification marker 100a will be used in combination with a road cone 150, as in the first embodiment, the identification marker 100a can be attached to the top of the road cone 150 regardless of whether the road cone 150 has a hole at the top.

[0081] According to this embodiment, similarly to the first embodiment, in a safety monitoring system 1000 that monitors a predetermined space such as a work site, by using an identification marker 100a configured with a spherical member, it is possible to stably recognize the identification marker 100a regardless of the position of the imaging device 200. Furthermore, even if the object to which the identification marker 100a is fixed is changed, the identification marker 100a can be appropriately fixed to various objects by appropriately replacing the attachment part 140.

[0082] The embodiments of the present invention and their modifications can be combined as appropriate as long as they are not mutually inconsistent. A product in which a person skilled in the art appropriately adds or deletes components or modifies designs, or adds or omits steps or modifies conditions based on the above-described embodiments or their modifications, is also included within the scope of the present invention as long as it includes the gist of the present invention.

[0083] Furthermore, even if there are other effects and advantages different from those brought about by the above-mentioned embodiments or their modified forms, if these are clear from the description in this specification or can be easily predicted by a person skilled in the art, they are naturally understood to be brought about by the present invention. [Explanation of symbols]

[0084] 100, 100a...Identification marker, 110, 110a...Marker body, 111, 112...Colored area, 113...Graphic image, 116...Screw hole, 120, 120a...Bottom hole, 121, 121a...Bottom, 130...Threaded portion, 140...Attachment portion, 140a...First surface, 140b...Second surface, 141...First threaded portion, 142...Second threaded portion, 150...Road cone, 160...Clamp, 200...Imaging device, 210...control unit, 220...imaging unit, 230...communication unit, 300...monitoring device, 310...control unit, 311...area identification unit, 312...person detection unit, 313...determination unit, 320...storage unit, 321...database unit (DB unit), 330...alarm unit, 340...communication unit, 400...monitoring target area, 451...support, 452...rope, 453...sign, 500...person, 1000, 1000a...safety monitoring system

Claims

1. An identification marker that can be recognized by an imaging device placed at a high position in the work site, a hole into which a support member disposed at the work site can be inserted to support the identification marker at a predetermined height; The identification marker is configured as a spherical member.

2. The identification marker of claim 1 , further comprising a threaded portion having a first end fixed in the hole and a second end protruding from the hole.

3. The attachment portion is configured to be able to fit into the hole, The spherical member has a screw hole in the hole, An identification marker as described in claim 1 or 2, wherein the attachment portion includes a first screw portion that screws into the screw hole and a second screw portion that is provided on a second surface opposite to the first surface on which the first screw portion is provided.

4. The identification marker according to claim 3 , wherein the first threaded portion and the second threaded portion have different nominal diameters.

5. The identification marker according to claim 1 , wherein a visually detectable color or graphic is marked on the surface of the spherical member.

6. 6. The identification marker according to claim 1, wherein a plurality of circular or polygonal figures are marked on the surface of the spherical member at positions point-symmetrical with respect to the center of the spherical member.

7. A method of using an identification marker according to any one of claims 1 to 6, comprising fitting the hole in the identification marker to a tip of a road cone, thereby using the identification marker in combination with the road cone.

8. A method of using an identification marker according to claim 2, comprising attaching the threaded portion of the identification marker to a clamp, thereby using the identification marker in combination with the clamp.

9. an imaging device that images a predetermined space; a monitoring device that analyzes the captured image transmitted from the imaging device; an identification marker disposed within the space; the identification marker is composed of a spherical member supported at a predetermined height by a support member, A safety monitoring system in which the monitoring device identifies the area to be monitored by extracting the identification marker from the captured image obtained from the imaging device, and detects whether or not a person is present in or around the area to be monitored based on the captured image.

10. further comprising an alarm device that issues an alarm within the space; The safety monitoring system of claim 9, wherein when the monitoring device determines that the person is present in the vicinity of the monitored area, it transmits an instruction signal to the alarm device to issue the alarm, and when it determines that the person is present in the monitored area, it transmits an instruction signal to another information processing device to notify that a person has entered the monitored area.

Images