Belt conveyor monitoring device, belt conveyor monitoring method and program

Abstract

To easily monitor a state of a belt of a belt conveyor based on a photographed image.SOLUTION: A belt conveyor monitoring device 40 modifies an area including a belt 11 in a belt photographed image 310 so that the area including the belt 11 in the belt photographed image 310 approaches a state photographed from a direction facing the belt 11, and performs processing to extract feature areas from the image of the modified area including the belt 11.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a belt conveyor monitoring device, a belt conveyor monitoring method, and a program. [Background technology]

[0002] If the belt of a belt conveyor breaks, the belt conveyor will no longer be able to transport objects. Therefore, it is desirable to monitor the condition of the belt. Therefore, it is considered to have an inspector visually inspect the condition of the belt. However, if an inspector visually inspects the condition of the belt when the belt conveyor is in operation, it is easy for an abnormality to be overlooked. On the other hand, if an inspector visually inspects the condition of the belt when the belt conveyor is not in operation, the timing of the inspection is limited when the belt conveyor is not in operation.

[0003] Therefore, Patent Documents 1 and 2 disclose a method in which an image of the belt is taken by an imaging device while the belt conveyor is in operation, and the state of the belt is monitored based on the taken image. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-17296 [Patent Document 2] JP 2021-179368 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the techniques described in Patent Documents 1 and 2, the position and shooting direction of the camera are adjusted in advance to be suitable for shooting the belt and then fixed. Depending on the installation environment of the belt conveyor, it may not be possible to install the camera in a position and direction suitable for shooting the belt. In addition, a workload is incurred in adjusting the position and shooting direction of the camera to be suitable for shooting the belt.

[0006] The present invention has been made in consideration of the above problems, and has an object to make it possible to easily monitor the state of a belt of a belt conveyor based on captured images. [Means for solving the problem]

[0007] The belt conveyor monitoring device of the present invention comprises an acquisition unit that acquires a captured image including the belt of a belt conveyor in operation, a modification unit that modifies the area including the belt in the captured image so that the area including the belt in the captured image approaches a state photographed from a direction facing the belt, and an image processing unit that performs processing to extract characteristic areas included in the area of ​​the belt from the image of the area including the belt after it has been modified by the modification unit.

[0008] The belt conveyor monitoring method of the present invention comprises an acquisition step of acquiring a photographed image including the belt of an operating belt conveyor; a modification step of modifying an area including the belt in the photographed image so that the area including the belt in the photographed image approaches a state in which the area is photographed from a direction facing the belt; an image processing step of processing to extract characteristic areas included in the belt area from the image of the area including the belt after it has been modified by the modification step; and a display step of displaying the position of the characteristic area on the belt on a monitoring screen.

[0009] The program of the present invention causes a computer to function as each unit of the belt conveyor monitoring device. Effect of the Invention

[0010] According to the present invention, the state of the belt of the belt conveyor can be easily monitored based on captured images. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram illustrating an example of a configuration of a conveying facility and a belt conveyor monitoring system. [Diagram 2] FIG. 2 is a diagram illustrating an example of a functional configuration of a belt conveyor monitoring device. [Diagram 3] FIG. 13 is a diagram showing an example of a photographed belt image. [Figure 4] 11A and 11B are diagrams illustrating an example of a process for projectively transforming a photographed belt image. [Diagram 5] 11A and 11B are diagrams illustrating an example of processing for an image after projective transformation. [Figure 6] FIG. 13 is a diagram showing an example of a graph showing the relationship between the deviation degree and the frame number and the belt length. [Figure 7] FIG. 13 is a diagram showing an example of an entire image. [Figure 8A] FIG. 13 is a diagram showing an example of an initial state of a monitoring screen. [Figure 8B] FIG. 13 is a diagram showing an example of a monitoring screen in a state where a file is selected. [Figure 8C] FIG. 13 is a diagram showing an example of a monitoring screen in which a frame number is specified. [Figure 9] 1 is a flowchart illustrating an example of a belt conveyor monitoring method. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In addition, when comparing objects such as length, position, size, spacing, direction, etc., being the same (matching) includes not only cases where they are strictly the same, but also cases where they are different within the scope of the gist of the invention (for example, cases where they differ within the tolerance range determined at the time of design).

[0013] <Overview of the conveyor equipment and belt conveyor monitoring system> FIG. 1 is a diagram illustrating an example of a configuration of a conveying facility and a belt conveyor monitoring system. In FIG. 1, in this embodiment, a case in which the transport facility includes a belt conveyor 10 and a storage device 20 is illustrated.

[0014] 1 illustrates an example of a belt conveyor 10 including a belt 11 and pulleys 12a to 12m. The front and rear ends of the belt 11 are connected to each other, forming an endless belt. When the front and rear ends of the belt 11 are connected, an endless portion (seam portion) is formed in the belt 11.

[0015] 1 illustrates an example in which the belt 11 travels around a conveying path defined by pulleys 12a-12m in the direction of an arrow line shown beside the belt 11 in FIG. 1. That is, FIG. 1 illustrates an example in which the traveling direction of the belt 11 is the direction of the arrow line. The traveling direction of the belt 11 may be the opposite direction to the direction of the arrow line. Furthermore, the belt conveyor 10 may be capable of switching between traveling in the direction of the arrow line and traveling in the opposite direction to the direction of the arrow line.

[0016] 1 illustrates an example in which pulleys 12a and 12b are head pulleys, pulleys 12c to 12d are tail pulleys, pulleys 12e to 12h are bend pulleys that change the direction of belt 11, pulley 12g is a tension pulley that applies tension to belt 11, pulleys 12j to 12k are drive pulleys that apply power to belt 11, and pulleys 12l to 12m are snub pulleys that prevent the drive pulleys from slipping. An electric motor (not shown) is connected to pulleys 12j to 12k, which are drive pulleys, via a reducer (not shown).

[0017] The storage device 20 is a device that stores the transported objects transported by the belt conveyor 10 and discharges the transported objects toward the belt 11. Thus, in this embodiment, a case where the transported objects dropped from the storage device 20 are transported by the belt conveyor 10 is illustrated. The storage device 20 is, for example, a hopper with a chute. In this case, when the gate of the hopper is opened, the transported objects in the hopper are discharged toward the belt 11 through the chute. Then, when the gate of the hopper is closed, the discharge of the transported objects in the hopper is stopped. In FIG. 1, four storage devices 20a to 20d are illustrated. The transported objects stored in the four storage devices 20a to 20d may be the same type of transported objects or different types of transported objects. In addition, the transported objects may be any of, for example, raw materials, materials, and products (including semi-finished products obtained in the process of manufacturing a finished product) as long as they can be transported by the belt conveyor. The belt conveyor itself may be a known belt conveyor and is not limited to the belt conveyor 10 illustrated in Fig. 1. The storage device itself may be a known storage device and is not limited to the storage device 20 illustrated in Fig. 1. For example, when the belt conveyor transports the transported object placed by an inspector or a robot, the transport facility does not need to include a storage device.

[0018] In FIG. 1, in this embodiment, a belt conveyor monitoring system including an imaging device 30, a belt conveyor monitoring device 40, and a working device 50 is illustrated. The photographing device 30 photographs an image including the belt 11. In this embodiment, a case is exemplified in which the photographing device 30 photographs a moving image as an image including the belt 11 while the belt conveyor 10 is in operation (when the belt 11 is moving). In the following description, an image including the belt 11 photographed by the photographing device 30 will be referred to as a belt photographed image as necessary. Note that the belt photographed image may be a still image. In this case, for example, the photographing device 30 may repeatedly photograph the belt photographed image at a predetermined time period.

[0019] In addition, in this embodiment, the photographing device 30 is a portable photographing device (portable photographing device), and the installation position of the photographing device 30 and the photographing conditions that affect the photographing range (photographing direction, angle of view, photographing magnification, etc.) are not determined in advance. In this embodiment, the installation position of the photographing device 30 and the photographing conditions that affect the photographing range (photographing direction, angle of view, photographing magnification, etc.) are determined, and once the setting of the photographing device 30 is completed, the installation position and the photographing conditions are not changed at least until the end of photographing while the belt 11 rotates once. For example, the photographing device 30 may be attached to a tripod when photographing.

[0020] 1 illustrates an example in which the photographing device 30 photographs an area between the pulleys 12g and 12i of the belt 11 as a photographing target area. As illustrated in FIG. 1, this area is assumed to be unable (or difficult) to face the photographing device 30 directly to the belt 11 due to the presence of an obstacle 13 or the like. Therefore, as illustrated in FIG. 1, this embodiment illustrates an example in which the photographing device 30 photographs a belt photographed image in a state where it is not directly facing the belt 11. However, the photographing device 30 may photograph a belt photographed image in a state where it is directly facing the belt 11.

[0021] The photographing device 30 is, for example, a portable ITV (Industrial Television). However, the photographing device 30 is not limited to a portable ITV. For example, the photographing device 30 may be a digital video camera or a mobile terminal device with a photographing function (for example, a tablet terminal or a smartphone). In addition, when photographing with the photographing device 30, the photographing target area may be illuminated by a lighting device (not shown).

[0022] The belt conveyor monitoring device 40 is a device that acquires a belt photographed image captured by the photographing device 30 and performs processing for monitoring the state of the belt 11 using the acquired belt photographed image. The belt conveyor monitoring device 40 may also monitor the state of the belt of a belt conveyor other than the belt conveyor 10 illustrated in Fig. 1 by using a belt photographed image of the belt conveyor. In other words, the belt conveyor monitoring device 40 can monitor the state of the belt of a plurality of belt conveyors.

[0023] The operating device 50 performs a process for allowing an inspector to view various pieces of information calculated by the belt conveyor monitoring device 40. The operating device 50 may be disposed, for example, at a position closer to the belt conveyor 10 than the belt conveyor monitoring device 40 (for example, in a room for giving operation instructions for the belt conveyor 10). In this case, an inspector of the belt conveyor 10 may view various pieces of information calculated by the belt conveyor monitoring device 40 using the operating device 50 and give operation instructions for the belt conveyor 10 based on the information. In addition, in this embodiment, a case is illustrated in which the belt conveyor monitoring device 40 and the operating device 50 are connected to each other so as to be able to communicate with each other via a network 60. The network 60 may be a wired network or a wireless network. In addition, the network 60 may be a LAN (Local Area Network) or another network (WAN (Wide Area Network)). In addition, the network 60 may be connected to the Internet.

[0024] In this embodiment, the belt conveyor monitoring device 40 and the working device 50 are in a server and client relationship, respectively. For example, when the network 60 is connected to the Internet, the belt conveyor monitoring device 40 serves as a web server for the working device 50, and the working device 50 may be configured to allow an inspector to view various pieces of information calculated by the belt conveyor monitoring device 40 by using a web browser. However, it is not necessarily required that the inspector be able to view various pieces of information calculated by the belt conveyor monitoring device 40 on the working device 50. For example, the belt conveyor monitoring system may not have the working device 50. In this case, for example, the various pieces of information calculated by the belt conveyor monitoring device 40 may be displayed on a computer display provided in the belt conveyor monitoring device 40 or a computer display connected to the belt conveyor monitoring device 40, so that the inspector can view the information.

[0025] <Belt conveyor monitoring device> FIG. 2 is a diagram showing an example of a functional configuration of the belt conveyor monitoring device 40. As shown in FIG. The hardware of the belt conveyor monitoring device 40 has, for example, one or more hardware processors such as a CPU (Central Processing Unit) and one or more memories such as a RAM (Random Access Memory) and a ROM (Read Only Memory) as hardware, and executes various calculations by executing one or more programs stored in the memory by the one or more hardware processors. Furthermore, the belt conveyor monitoring device 40 has an input device and an output device as hardware. The belt conveyor monitoring device 40 may be realized by a PLC (Programmable Logic Controller) or by dedicated hardware such as an ASIC (Application Specific Integrated Circuit). The hardware of the working device 50 can be realized by, for example, the same hardware as the hardware of the belt conveyor monitoring device 40.

[0026] In Figure 2, this embodiment illustrates an example in which the belt conveyor monitoring device 40 includes an acquisition unit 210, a first reception unit 220, a change unit 230, an image processing unit 240, a calculation unit 250, a creation unit 260, a second reception unit 270, a display processing unit 280, and an output unit 290.

[0027] <<Acquisition part 210>> The acquisition unit 210 acquires a belt photographed image. In this embodiment, a case is exemplified in which the acquisition unit 210 acquires a belt photographed image by wireless communication between a communication device provided in the photographing device 30 or a communication device connected to the photographing device 30 and the belt conveyor monitoring device 40. However, the form in which the acquisition unit 210 acquires a belt photographed image is not limited to this form. For example, the acquisition unit 210 may acquire a belt photographed image by wired communication between a communication device provided in the photographing device 30 or a communication device connected to the photographing device 30 and the belt conveyor monitoring device 40. In addition, the acquisition unit 210 may acquire a belt photographed image transmitted from a communication device provided in the photographing device 30 or a communication device connected to the photographing device 30 via a network. In addition, when a belt photographed image captured by the photographing device 30 is stored in an external storage device (a device other than the photographing device 30 and the belt conveyor monitoring device 40), the acquisition unit 210 may acquire the belt photographed image from the external storage device.

[0028] FIG. 3 is a diagram showing an example of a belt photographed image. As described above, in this embodiment, a case where the belt photographed image is a moving image is illustrated. Therefore, in this embodiment, a case where the acquisition unit 210 acquires belt photographed images (frame images) photographed at a predetermined frame rate is illustrated. Belt photographed images 310a to 310c shown in FIG. 3(a) to FIG. 3(c) are frame images photographed at different times. In the following description, when there is no need to distinguish between the belt photographed images 310a to 310c, the belt photographed images 310a to 310c are referred to as belt photographed images 310 as necessary.

[0029] As described above, in this embodiment, a belt photographic image is taken with the photographing device 30 not facing the belt 11. The photographing device 30 facing the belt 11 means, for example, that all of the following conditions (I), (II), and (III) are satisfied. (I) The traveling direction of the belt 11 coincides with one of the vertical direction (lengthwise direction) and the horizontal direction (widthwise direction) of the belt photographed image 310. (II) The width direction of the belt 11 coincides with the other of the vertical direction (lengthwise direction) and the horizontal direction (widthwise direction) of the belt photographed image 310. (III) The photographing direction (optical axis direction) of the photographed image 310 coincides with the normal direction of the belt 11. In this case, the image capturing device 30 not facing the belt 11 means that at least one of (I), (II), and (III) is not satisfied.

[0030] 3 illustrates a case in which the width direction of the belt 11 coincides with the horizontal direction of the photographed image 310 of the belt, the vertical direction of the photographed image 310 of the belt does not coincide with the traveling direction of the belt 11, and the photographing direction (optical axis direction) of the photographed image 310 does not coincide with the normal direction of the belt 11. Note that the width direction of the belt 11 does not have to coincide with the horizontal direction of the photographed image 310 of the belt.

[0031] In Fig. 3(a) to Fig. 3(c), the belt photographed images 310a to 310c include an obstacle 13. It is assumed here that the position, shape, and size of the obstacle 13 in the belt photographed images 310a to 310c (each frame) will not change unless the installation position of the photographing device 30 and the photographing conditions are changed. Also, in Fig. 3(a) to Fig. 3(c), the belt photographed images 310a to 310c show an example in which a shadow 320 of the obstacle 13 is reflected on the belt 11. It is assumed here that the position, shape, and size of the shadow 320 of the obstacle 13 in the belt photographed images 310a to 310c will not change unless the installation position of the photographing device 30 and the photographing conditions are changed, at least during the time it takes for the belt 11 to make one revolution.

[0032] FIG. 3(a) illustrates an example in which only the image of the stationary part of the belt 11 is included in the belt photographed image 310a. Usually, the stationary part is a region that occupies most of the belt 11, and is a part that is recognized as having no change from the surface state before the front and rear ends are connected in the belt conveyor monitoring device 40. For example, among the regions of the belt 11 in one belt photographed image 310, a region in which the pixel value (gradation value) is within a predetermined range and a region in which the time change of the pixel value (gradation value) in the belt photographed image 310 (for example, the difference in pixel value between multiple belt photographed images 310 that are consecutive in time) is within a predetermined range correspond to the image of the stationary part. In FIG. 3(a) to FIG. 3(c), the region indicated in white in the image of the belt 11 and the region of the shadow 320 of the obstacle 13 are examples of the image of the stationary part.

[0033] On the other hand, in Fig. 3(b) and Fig. 3(c), an example is illustrated in which an image of a non-steady state part is included in the belt photographed images 310b and 310c as an image of the belt 11. The non-steady state part is, for example, a part of the region of the belt 11 that is recognized by the belt conveyor monitoring device 40 as having a change from the surface state before the leading end and the trailing end are connected. The non-steady state part includes, for example, an endless part of the belt 11 formed by connecting the leading end and the trailing end of the belt 11, and a soiled or damaged part of the belt 11 formed after the belt conveyor 10 is operated. The steady state part can also be said to be a part other than the non-steady state part.

[0034] For example, among the regions of the belt 11 in the belt photographed image 310, the regions in which the pixel values ​​(gradation values) in the belt photographed image 310 are not within the above-mentioned specified range and the regions in which the change over time in the pixel values ​​(gradation values) in the belt photographed image 310 is not within the above-mentioned specified range correspond to images of non-steady parts.

[0035] As described above, the belt 11 has an endless portion. Fig. 3(b) illustrates an example in which the endless portion 330 of the belt 11 is included in the belt photographed image 310b. Fig. 3(c) illustrates an example in which a damaged portion 340 occurring in the belt 11 is included in the belt photographed image 310c. Thus, Figs. 3(b) and 3(c) illustrate an example in which the endless portion 330 and the damaged portion 340 are included as non-steady portions in the belt photographed images 310b to 310c.

[0036] In this embodiment, the acquisition unit 210 repeatedly acquires belt photographed images 310 (frame images) at a predetermined frame rate during the period when the belt 11 goes around the conveying path of the belt conveyor 10. The fact that the belt 11 has gone around the conveying path of the belt conveyor 10 is determined based on, for example, the total length of the conveying path of the belt conveyor 10 and the speed of the belt 11. In addition, in this embodiment, a case is illustrated in which each belt photographed image 310 (frame image) is given identification information (for example, an IP address) of the photographing device 30 that photographed the belt photographed image 310, a frame number, a photographing time, and the like. In the following description, the identification information of the photographing device 30 is referred to as camera identification information as necessary.

[0037] As described above, the belt conveyor monitoring device 40 may monitor the state of the belt of a belt conveyor other than the belt conveyor 10 illustrated in Fig. 1 by using a belt photographed image of the belt conveyor. In this case, the belt photographed image photographed by the different photographing device 30 is acquired by the acquisition unit 210. The first reception unit 220, the change unit 230, the image processing unit 240, the calculation unit 250, the creation unit 260, the second reception unit 270, the display processing unit 280, and the output unit 290 use information (camera identification information, frame number, and photographing time) attached to the belt photographed image as a key to identify which belt conveyor the belt photographed image is a photographed image of, and perform the process described below for each belt conveyor.

[0038] <<First Reception Unit 220, Display Processing Units 280, 290>> The first reception unit 220 receives designation by an inspector (user) of a first point, a second point, a third point, and a fourth point selected from the belt photographed image 310. The first point and the second point are spaced apart in the traveling direction of the belt 11 and are points at positions corresponding to one end of the belt 11 in the width direction. The third point and the fourth point are spaced apart in the traveling direction of the belt 11 and are points at positions corresponding to the other end of the belt 11 in the width direction.

[0039] In this embodiment, the display processing unit 280 performs processing for displaying information including the belt photographed image 310 acquired by the acquisition unit 210 on the display device. In addition, in this embodiment, the display device is a computer display provided in the working device 50 or a computer display connected to the working device 50. In this case, for example, the display processing unit 280 creates a belt display screen that is a screen that displays information including the belt photographed image 310. Then, the output unit 290 outputs information required for the working device 50 to display the belt display screen on the computer display as screen information to the working device 50. The working device 50 displays the belt display screen on the computer display based on the screen information. At this time, the working device 50 may request screen information from the belt conveyor monitoring device 40, which serves as a web server, based on an instruction by an inspector of the working device 50 via a web browser. In FIG. 4(a), the belt photographed image 310b shown in FIG. 3(b) is illustrated as the belt photographed image 310 in the belt display screen displayed in this way. Incidentally, "belt travel direction →" shown in FIG. 4(a) etc. indicates the travel direction of belt 11 (the direction of the arrow line shown in FIG. 1).

[0040] The belt display screen includes a GUI (Graphical User Interface) for the inspector to specify positions in the belt photographed image 310 displayed on the belt display screen. In this embodiment, a case is illustrated in which the inspector of the working device 50 specifies positions in the belt photographed image 310 displayed on the belt display screen to specify the positions of a first point, a second point, a third point, and a fourth point.

[0041] 4(a) illustrates a state in which an inspector has specified the positions of a first point 411, a second point 412, a third point 413, and a fourth point 414. The first point 411 and the second point 412 are spaced apart in the traveling direction of the belt 11, and are points at positions corresponding to one side (left side) end of the belt 11 in the width direction. The third point 413 and the fourth point 414 are spaced apart in the traveling direction of the belt 11, and are points at positions corresponding to the other side (right side) end of the belt 11 in the width direction.

[0042] In this embodiment, a case is illustrated in which the positions of the first point 411, the second point 412, the third point 413, and the fourth point 414 remain the same in the belt photographed image 310 (each frame image) until re-designation by the inspector.

[0043] Furthermore, the inspector of the working device 50 may or may not specify positions that strictly correspond to the positions of the widthwise ends of the belt 11 in the belt photographed image 310. For example, the inspector of the working device 50 may specify the positions of the first point 411, the second point 412, the third point 413, and the fourth point 414 so as to satisfy the following condition (IV). In other words, the positions specified by the inspector of the working device 50 do not need to strictly correspond to the positions of the widthwise ends of the belt 11 in the belt photographed image 310, but may satisfy, for example, the following condition (IV).

[0044] (IV) The width direction length of belt 11 in a quadrangle having vertices at first point 411, second point 412, third point 413, and fourth point 414 is 0.8 to 1.2 times the width direction length of belt 11 in belt photographed image 310.

[0045] In addition, in this embodiment, since divided images 721 to 723 described later are generated, the positions of the first point 411, the second point 412, the third point 413, and the fourth point 414 may be specified so as to satisfy the following condition (V). (V) The distance L1 between the first point 411 and the second point 412, and the distance L2 between the third point 413 and the fourth point 414 are each set to a length such that the length L3 in the vertical direction (the direction of travel of belt 11) of the quadrangle (rectangle or square) after projective transformation described later is longer than a length L4 that is predetermined as the length in the vertical direction (the direction of travel of belt 11) of divided images 721 to 723 described later (see L1, L2, L3, and L4 attached to Figures 4(a), 4(b), and 7).

[0046] In this embodiment, a case is exemplified in which the first reception unit 220 receives the positions of the first point 411, the second point 412, the third point 413, and the fourth point 414 designated by the inspector of the working device 50. However, this is not necessarily required. For example, the belt conveyor monitoring device 40 may display the belt display screen on a computer display provided in the belt conveyor monitoring device 40 or a computer display connected to the belt conveyor monitoring device 40. In this case, the inspector of the belt conveyor monitoring device 40 may specify the positions of the first point 411, the second point 412, the third point 413, and the fourth point 414. In this case, the first reception unit 220 accepts the positions of the first point 411, the second point 412, the third point 413, and the fourth point 414 designated by the inspector of the belt conveyor monitoring device 40.

[0047] Also, the belt conveyor monitoring device 40 may not specify the positions of the belt photographed image 310 displayed on the belt display screen as the inspector. For example, the belt conveyor monitoring device 40 may calculate the positions of the first point 411, the second point 412, the third point 413, and the fourth point 414 based on the belt photographed image 310. For example, the belt conveyor monitoring device 40 may specify the area of ​​the belt 11 in the belt photographed image 310 based on the pixel value (gradation value) of the belt photographed image 310. For example, the contour (edge) of the image may be extracted by using a known edge extraction process or the like, and the contour corresponding to the belt 11 among the extracted contours may be further extracted by using a known pattern matching or the like. Then, the belt conveyor monitoring device 40 may calculate the positions that satisfy the above-mentioned conditions (IV) and (V) from among the positions of the extracted contours corresponding to the belt 11 as the positions of the first point 411, the second point 412, the third point 413, and the fourth point 414. In this case, the belt conveyor monitoring device 40 does not need to include the first receiving unit 220.

[0048] <<Modification section 230>> The modification unit 230 modifies the area including the belt 11 in the belt photographed image 310 so that the area including the belt 11 in the belt photographed image 310 approaches a state where the area is photographed from a direction facing the belt 11. In this case, it is preferable that the modification unit 230 modifies the area including the belt 11 in the belt photographed image 310 so that the area including the belt 11 in the belt photographed image 310 is photographed from a direction facing the belt 11. Therefore, in this embodiment, the modification unit 230 performs projective transformation on the area including the belt 11 in the belt photographed image 310 so that the shape of the area including the belt 11 in the belt photographed image 310 becomes a rectangular or square image of a predetermined size (having a predetermined length and width), thereby exemplifying a case where the area including the belt 11 in the belt photographed image 310 is photographed from a direction facing the belt 11. Note that the projective transformation itself can be realized by a known technique, and therefore a detailed description thereof will be omitted here.

[0049] In this embodiment, a case will be illustrated in which a quadrangular region having vertices of the first point 411, the second point 412, the third point 413, and the fourth point 414 is a region including the belt 11 in the belt photographed image 310. In this case, the change unit 230 performs projective transformation on the quadrangular region having vertices of the first point 411, the second point 412, the third point 413, and the fourth point 414 so that the quadrangular region becomes a rectangular or square image of a predetermined size.

[0050] In the following description, the image obtained by the projective transformation as described above is referred to as a post-projective transformation image as necessary. FIG. 4(b) shows an example of a post-projective transformation image 420. The post-projective transformation image 420 shown in FIG. 4(b) is obtained by projectively transforming the image of the quadrangular region having vertices of the first point 411, the second point 412, the third point 413, and the fourth point 414 shown in FIG. 4(a) so that the shape of the quadrangular region becomes a rectangle of a predetermined size. The aspect ratio of the quadrangle (rectangle or square) after the projective transformation (the aspect ratio of the post-projective transformation image 420) may be the same as or different from the aspect ratio of the belt photographed image 310.

[0051] In this embodiment, the change unit 230 repeatedly creates the post-projection transformation image 420 as described above using each of the belt photographed images 310 (frame images) acquired by the acquisition unit 210 at a predetermined frame rate during the period when the belt 11 goes around the conveyance path of the belt conveyor 10. As a result, each post-projection transformation image 420 is obtained at a timing corresponding to the frame rate at which the belt photographed image 310 is photographed during the period when the belt 11 goes around the conveyance path of the belt conveyor 10. In this embodiment, the change unit 230 assigns to each post-projection transformation image 420 the camera identification information, frame number, and photographing time that are assigned to the belt photographed image 310 (frame image) from which the post-projection transformation image 420 is created. Note that the frame number does not have to be assigned to the post-projection transformation image 420.

[0052] In this embodiment, the case where the area including the belt 11 in the belt photographed image 310 is projectively transformed is exemplified. Doing so is preferable because it allows the area including the belt 11 in the belt photographed image 310 to be photographed from a direction facing the belt 11. However, it is not necessarily required to do so. For example, the area including the belt 11 in the belt photographed image 310 may be rotated by affine transformation or the like so that the area including the belt 11 in the belt photographed image 310 approaches a state where the area including the belt 11 in the belt photographed image 310 is photographed from a direction facing the belt 11.

[0053] <<Image processing unit 240>> The image processing unit 240 performs processing for extracting a feature region included in the belt 11 region from the image of the region including the belt 11 after the modification by the modification unit 230. The feature region is a region that is a candidate for a non-stationary part of the belt 11 (for example, at least one of the endless part 330 and the damaged part 340). In this embodiment, a case where the image processing unit 240 performs processing for extracting a feature region included in the belt 11 region from the post-projection transformation image 420 is exemplified. In addition, in this embodiment, a case where the processing for extracting a feature region included in the belt 11 region is image processing is exemplified. More specifically, in this embodiment, a case where the image processing unit 240 applies a background difference method to the post-projection transformation image 420 is exemplified. In the following description, the feature region included in the belt 11 region is abbreviated to feature region as necessary.

[0054] The background subtraction method itself is realized by a known technique. In the background subtraction method, a background image is created. In this embodiment, as shown in FIG. 5(a), a case is illustrated in which a background image is created using n projectively transformed images 420a to 420c created by the modification unit 230 as described above from belt photographed images 310 taken n frames before, n-1 frames before, . . . , 1 frame before the belt photographed image 310 from which the projectively transformed image 420 from which the feature region is extracted is created. n is an integer equal to or greater than 2, for example, 5. In this case, for example, the image processing unit 240 creates a background image having the arithmetic mean value of the pixel values ​​(tone values) of each pixel of the n projectively transformed images 420a to 420c as the pixel value of each pixel. FIG. 5(b) shows an example of a background image 510.

[0055] In the present embodiment, a case is exemplified where a plurality of post-projection transformation images 420a to 420c obtained from a plurality of past belt photographed images 310 are used to create a background image 510 to be compared with a post-projection transformation image 420 from which a feature region is to be extracted. However, the background image does not necessarily have to be obtained in this manner. For example, an inspector may specify a belt photographed image 310 to be used for creating a background image offline. For example, an inspector may search for (one) belt photographed image 310 that does not include a non-steady part from a plurality of past belt photographed images 310 as a belt photographed image 310 to be used for creating a background image. In this case, a post-projection transformation image 420 created as described above from the belt photographed image 310 searched by the inspector may be used as the background image.

[0056] In the background difference method, a foreground image is created in which the pixel value of each pixel is a binarized absolute value of the difference between the pixel value (tone value) of each pixel between the projectively transformed image 420 from which the feature region is extracted and the background image 510. At this time, a process for reducing noise (for example, at least one of an expansion process and an erosion process) may be performed on at least one of the foreground image and the background image. FIG. 5(c) shows an example of the foreground image 520. The foreground image 520 shown in FIG. 5(c) is a foreground image created based on the projectively transformed image 420 shown in FIG. 4(b) and the background image 510 shown in FIG. 5(b). In the example shown in FIG. 5(c), the black area in the foreground image 520 is an area that represents a candidate for the feature region. In the foreground image, an area having a pixel value greater than the binarization threshold (an area with a pixel value of 1, a black area in FIG. 5(c)) represents a candidate for the non-steady part.

[0057] In this embodiment, the image processing unit 240 repeatedly creates the foreground image 520 as described above using each of the post-projection transformation images 420 at each timing corresponding to the frame rate at which the belt photographed image 310 was photographed. As a result, during the period in which the belt 11 makes one revolution on the conveying path of the belt conveyor 10, each of the foreground images 520 at a timing corresponding to the frame rate at which the belt photographed image 310 was photographed is obtained. In this embodiment, the image processing unit 240 assigns to each foreground image 520 the camera identification information, frame number, and photographing time assigned to the post-projection transformation image 420 from which the foreground image 520 was created. Note that the frame number does not have to be assigned to the foreground image 520.

[0058] In the present embodiment, a case has been exemplified in which foreground image 520 is created by performing image processing using a background subtraction method. However, the processing for extracting the characteristic region is not limited to such processing. The processing for extracting the characteristic region may be, for example, processing using a machine learning model (for example, a convolutional neural network) that calculates the characteristic region from post-projection transformation image 420. The processing for extracting the characteristic region in this manner is not limited to so-called image processing.

[0059] <<Calculation Unit 250>> Based on the result of processing by the image processing unit 240, the calculation unit 250 calculates an evaluation index for evaluating the amount of characteristic regions included in the region of the belt 11. In this embodiment, a case in which the calculation unit 250 calculates the evaluation index based on pixel values ​​of the foreground image 520 will be illustrated.

[0060] As described above, in the example shown in FIG. 5(c), black regions in foreground image 520 are regions that represent candidates for feature regions. On the other hand, white regions in foreground image 520 correspond to regions of steady parts. Therefore, in this embodiment, a case is illustrated in which calculation unit 250 calculates the sum of the areas (number of pixels) of black regions (blobs) in foreground image 520 as the evaluation index. However, as shown in FIG. 5(c), foreground image 520 may contain noises 521a to 521c other than endless portion 330. Therefore, in this embodiment, a case is illustrated in which calculation unit 250 excludes regions of black regions in foreground image 520 whose areas are equal to or smaller than a threshold value from the calculation of the evaluation index. Therefore, in the example shown in FIG. 5(c), the areas of black regions corresponding to noises 521a to 521c are excluded from the calculation of the evaluation index, and the area of ​​black regions corresponding to endless portion 330 is calculated as the evaluation index. For ease of explanation, it is assumed in Figures 3 to 5 that the black areas are known to be endless sections 330, etc., but this embodiment illustrates a case in which the belt conveyor monitoring device 40 does not recognize at this point in time that the area indicated by the symbol 330 in Figure 5(c) etc. is an endless section area.

[0061] In the following description, the evaluation index calculated as above will be referred to as deviation degree as necessary. The deviation degree corresponds to an evaluation of how much the pixel value (tone value) of each pixel in the area of ​​the belt 11 included in the image (image after projective transformation 420 in this embodiment) changed by the change unit 230 deviates from the pixel value corresponding to the stationary part of the belt 11, in the entire image. The evaluation index is not limited to the deviation degree. For example, the evaluation index may be a value obtained by dividing the deviation degree by the area (number of pixels) of the foreground image 520. The evaluation index may also be a value obtained by subtracting the deviation degree from the area (number of pixels) of the foreground image 520. The deviation degree is an evaluation index for evaluating the amount of characteristic areas included in the area of ​​the belt 11 (the greater the deviation degree, the greater the amount of characteristic areas). On the other hand, the value obtained by subtracting the degree of deviation from the area (number of pixels) of foreground image 520 is an evaluation index for evaluating the sparseness of the amount of characteristic regions included in the area of ​​belt 11 (the larger this value, the smaller the amount of characteristic regions).

[0062] In this embodiment, the calculation unit 250 repeatedly calculates the deviation degree as described above using each of the foreground images 520 at each timing corresponding to the frame rate when the belt photographed image 310 is photographed. As a result, each deviation degree at a timing corresponding to the frame rate when the belt photographed image 310 is photographed during the period when the belt 11 goes around the conveyance path of the belt conveyor 10 is obtained. In this embodiment, the calculation unit 250 assigns to each deviation degree the camera identification information, frame number, and photographing time that are assigned to the foreground image 520 from which the deviation degree is calculated. Note that the frame number does not have to be assigned to the deviation degree.

[0063] In this embodiment, a case is illustrated in which camera identification information, frame numbers, and shooting times are assigned to the belt photographed image 310 (frame image), the projectively transformed image 420, the foreground image 520, and the deviation degree, respectively. Based on the camera identification information, frame numbers, and shooting times assigned to the projectively transformed image 420, the foreground image 520, and the deviation degree, it is identified which belt photographed image 310 (frame image) the projectively transformed image 420, the foreground image 520, and the deviation degree correspond to. Note that the frame number does not have to be used in this identification.

[0064] As described above, the fact that the belt 11 has completed one revolution of the conveying path of the belt conveyor 10 is determined based on, for example, the total length of the conveying path of the belt conveyor 10 and the speed of the belt 11. Therefore, for example, the position of the subject of the belt photographed image 310 (frame image) captured first when the belt 11 completes one revolution of the conveying path of the belt conveyor 10 may be set as the reference position. The reference position is expressed as a position on the conveying path. In this case, the m-th belt photographed image 310 (frame image) captured thereafter can be determined to be the belt photographed image 310 at a position m×v÷f(m) away from the reference position along the traveling direction of the belt 11 based on the speed v (m / s) of the belt 11 and the frame rate f (fps) when capturing the belt photographed image 310. Then, as described above, the post-projection transformation image 420, the foreground image 520, and the deviation are linked to the belt photographed image 310 by the camera identification information, the frame number, and the capture time. Therefore, it is possible to specify how far the post-projection transformation image 420, the foreground image 520, and the deviation degree are from the reference position in the traveling direction of the belt 11.

[0065] In this embodiment, the calculation unit 250 creates a graph showing the relationship between the deviation degree, the frame number, and the belt length. FIG. 6 is a diagram showing an example of a graph 610 showing the relationship between the deviation degree, the frame number, and the belt length. The belt length shown in FIG. 6 represents the distance from a reference position in the traveling direction of the belt 11, with the reference position being 0 (zero). The graph 610 shown in FIG. 6 shows the deviation degree obtained when the belt 11 makes one revolution around the conveying path of the belt conveyor 10. That is, the minimum value and the maximum value on the horizontal axis of the graph 610 correspond to the same position on the conveying path of the belt conveyor 10. The calculation unit 250 repeatedly creates such a graph 610, and the deviation degree obtained when the belt 11 makes one revolution around the conveying path of the belt conveyor 10 is repeatedly calculated. In this embodiment, graph 610 is an example of the relationship between the evaluation index (deviation in this embodiment) calculated based on the result of processing by the image processing unit 240 and information (frame number and belt length in this embodiment) for identifying the position of the belt 11 (position on the conveying path of the belt conveyor 10 in this embodiment) contained in the image that was the subject of the processing (image after projective transformation 420 in this embodiment). It is preferable, but not necessary, for the calculation unit 250 to calculate the evaluation index (the deviation in this embodiment). For example, the image after processing by the image processing unit 240 may be displayed.

[0066] <<Creation Department 260>> The creation unit 260 creates a plurality of divided images based on the image of the area including the belt 11 after it has been changed by the change unit 230. The plurality of divided images are images of each divided area obtained by dividing an area of ​​one revolution of the belt 11 in the traveling direction of the belt 11. In addition, in this embodiment, a case is illustrated in which the creation unit 260 further creates an entire image, which is an image in which the plurality of divided images are arranged in the order in which they were photographed.

[0067] As described above, in this embodiment, during the period when the belt 11 goes around the conveying path of the belt conveyor 10, the change unit 230 creates each of the post-projection transformation images 420 at a timing corresponding to the frame rate at which the belt photographed image 310 was photographed. Therefore, in this embodiment, the creation unit 260 creates an example of a case in which, for each of these post-projection transformation images 420, the creation unit 260 extracts a part of the post-projection transformation image 420 as a divided image so that two post-projection transformation images 420 adjacent to each other in the photographing order (frame number) do not include an overlapping area. In addition, in this embodiment, the divided images have the same shape and size, and are rectangular or square in shape.

[0068] For example, when the speed of the belt 11 and the photographing conditions are constant, the creation unit 260 may create the divided images as follows. The creation unit 260 calculates the distance (number of pixels) that the belt 11 travels per frame in the post-projection transformation image 420 based on the speed of the belt 11, the photographing conditions (frame rate, angle of view, photographing magnification, etc.) when photographing the belt photographed image 310, and the size (length and width) and number of pixels of the post-projection transformation image 420. Then, the creation unit 260 calculates the area included in the post-projection transformation image 420 one frame before the post-projection transformation image 420 based on the distance. Then, the creation unit 260 extracts a rectangular area of ​​a predetermined size from the post-projection transformation image 420, excluding the area included in the post-projection transformation image 420 one frame before the post-projection transformation image 420, as the divided area described above, to create the divided image. The creation unit 260 may also create divided images corresponding to the belt photographed image 310 in a pre-scheduled time period. For ease of explanation, the example shows a case where divided images corresponding to the belt photographed image 310 taken when the speed of the belt 11 is constant are created. However, divided images corresponding to the belt photographed image 310 taken when the speed of the belt 11 is not constant may also be created. In this case, the sizes of the divided images may differ from one another.

[0069] The creation unit 260 creates an entire image by arranging the thus created multiple divided images in the order of shooting (in the order of frame numbers). FIG. 7 is a diagram showing an example of an entire image 710. One square shown in FIG. 7 shows one divided image. FIG. 7 illustrates a case where the earlier the belt photographed image 310 (frame image) is taken, the more to the left and the upper the divided image is to be created ("frame number ->" shown in FIG. 7 and the like indicates this). Therefore, FIG. 7 illustrates a case where the upper left divided image 721 is an image after projective transformation 420 based on the belt photographed image 310 (frame image) taken first when the belt 11 goes around the conveying path of the belt conveyor 10, which is the original divided image. Also, FIG. 7 illustrates a case where the lower right divided image 722 is an image after projective transformation 420 based on the belt photographed image 310 (frame image) taken last when the belt 11 goes around the conveying path of the belt conveyor 10, which is the original divided image. FIG. 7 illustrates an example in which the traveling direction of the belt 11 is the leftward direction on the paper surface (see "←belt traveling direction" shown in FIG. 7).

[0070] 7 illustrates an example in which two divided images adjacent to each other in the photographing order and disposed adjacent to each other in the overall image 710 are arranged without any gaps. This allows the inspector to easily view the overall state of the belt 11 in the overall image 710.

[0071] 7, for convenience of notation, the number of divided images is made smaller than the number of belt photographed images 310 (frame images) photographed during the period when the belt 11 goes around the conveying path of the belt conveyor 10. Also, for convenience of notation, in FIG. 7, images other than the endless portion of the divided image 723 including the endless portion 330 are omitted from illustration, and images displayed in the divided images other than the divided image 723 are omitted from illustration (i.e., shown in white). In this embodiment, the creation unit 260 assigns to each divided image 520 the camera identification information, frame number, and shooting time assigned to the post-projection transformation image 420 from which the divided image was created. Note that the frame number does not have to be assigned to the divided image.

[0072] In this embodiment, the creation unit 260 creates a set of information of the belt photographed image 310, the projectively transformed image 420, the foreground image 520, the deviation, and the whole image 710 as data of one file as information during one revolution of the belt 11, every time the belt 11 makes one revolution around the conveying path of the belt conveyor 10. The file is created based on, for example, the total length of the conveying path of the belt conveyor 10, the speed of the belt 11, the frame rate at which the belt photographed image 310 is photographed, and the camera identification information, frame number, and photographing time given to the belt photographed image 310, the projectively transformed image 420, the foreground image 520, and the deviation. In this case, the creation unit 260 creates a set of, for example, a belt photographed image 310 acquired during a period when the belt 11 goes around the conveying path of the belt conveyor 10, a projectively transformed image 420 to which the same information as the camera identification information, frame number, and photographing time given to the belt photographed image 310 is given, a foreground image 520, and a deviation degree, and an entire image 710 created using the projectively transformed image 420, as data of one file, and stores the set in a storage medium. In this embodiment, the file name is the photographing time of the belt photographed image 310 (frame image) first photographed when the belt 11 goes around the conveying path of the belt conveyor 10. However, the file name is not limited. The creation unit 260 may automatically give a file name to each file, or a file name specified by an inspector may be given to each file. Furthermore, the storage medium for storing the file may be a storage medium provided in the belt conveyor monitoring device 40, or may be a storage medium external to the belt conveyor monitoring device 40 that can be referenced by the belt conveyor monitoring device 40.

[0073] It is preferable to create the entire image 710 so that the inspector can check the state of one revolution of the belt 11 at once. However, the creation unit 260 does not necessarily need to create the entire image 710. For example, the creation unit 260 may create an image in which a predetermined number of divided images, including a divided image created from the post-projection transformation image 420 to which the same frame number as that assigned to the foreground image 520 whose deviation degree exceeds the threshold value is assigned, are arranged in the order of shooting of the predetermined number of divided images having consecutive shooting orders (frame numbers). In this case, the predetermined number is less than the number of divided images constituting the entire image 710.

[0074] <<Second Reception Unit 270, Display Processing Unit 280, Output Unit 290>> The display processing unit 280 performs processing for displaying information including the entire image 710 on the display device. In this embodiment, the display device is a computer display included in the working apparatus 50 or a computer display connected to the working apparatus 50. In addition, in this embodiment, the display processing unit 280 creates a monitoring screen, and the output unit 290 outputs information required for the working apparatus 50 to display the monitoring screen on the computer display as screen information to the working apparatus 50. In this case, the working apparatus 50 displays the monitoring screen on the computer display based on the screen information. At this time, the working apparatus 50 may request screen information from the belt conveyor monitoring device 40, which serves as a web server, based on an instruction by an inspector of the working apparatus 50 via a web browser.

[0075] Here, a description will be given of an example of display information on the monitoring screen 800. Fig. 8A is a diagram showing an example of the monitoring screen 800 in its initial state. In this embodiment, FIG. 8A illustrates an example in which a monitoring screen 800 includes a side menu section 810, a deviation degree display section 820, a frame number input section 830, an entire image display section 840, a frame image display section 850, and a video display section 860.

[0076] The side menu section 810 includes a camera selection section 811 , a file selection section 812 , and a download section 813 .

[0077] The camera selection field 811 is used by the inspector to select the imaging device 30. Fig. 8A illustrates an example in which camera identification information is selected from a pull-down menu.

[0078] The file selection field 812 is for the inspector to select a file. Fig. 8A illustrates an example in which a file name is selected from a pull-down menu. The file selected in the file selection field 812 is a file that stores information on a set of belt photographed image 310, post-projection transformation image 420, foreground image 520, deviation degree, and whole image 710 as information for the period during which belt 11 makes one revolution.

[0079] As described above, in this embodiment, the file name is the time of the first belt photographed image 310 (frame image) taken when the belt 11 goes around the conveying path of the belt conveyor 10. Also, as described above, in this embodiment, belt photographed images taken by different photographing devices 30 may be acquired by the acquisition unit 210. Therefore, when there are multiple files in which belt photographed images taken by multiple photographing devices 30 at the same time are stored, the file names of the multiple files are the same. However, the photographing devices that took the belt photographed images included in those files are different. Therefore, one file can be selected by selecting the camera identification information and the file name in the camera selection field 811 and the file selection field 812. Note that, for example, when the photographing information and the camera identification information are included in the file name, the monitoring screen 800 does not need to have the camera selection field 811.

[0080] The download section 813 includes buttons 813a to 813f that are operated when downloading information displayed on the monitoring screen 800 to the working device 50 as described below. The button 813a is a button that is pressed by the inspector when downloading data on the deviation degree. The button 813b is a button that is pressed by the inspector when downloading data on the whole image 710. The button 813c is a button that is pressed by the inspector when downloading data on a specified frame image. The specified frame image is a frame image with a frame number specified by the inspector. The button 813d is a button that is pressed by the inspector when downloading data on a previous frame image. The previous frame image is the frame image one frame before the specified frame image. The button 813e is a button that is pressed by the inspector when downloading data on a subsequent frame image. The subsequent frame image is the frame image one frame after the specified frame image. The button 813f is a button that is pressed by the inspector when downloading data on a moving image. The moving image is a belt photographed image 310 (moving image).

[0081] In the initial state shown in FIG. 8A, the camera selection field 811, file selection field 812, deviation display field 820, frame number input field 830, whole image display field 840, frame image display field 850, and video display field 860 are blank (unselected and undisplayed).

[0082] The second reception unit 270 receives an operation of an inspector on the monitoring screen 800. In this embodiment, a case is illustrated in which the working device 50 transmits information indicating the operation content of the inspector of the working device 50 to the belt conveyor monitoring device 40, and the second reception unit 270 receives and thereby accepts the information.

[0083] The inspector of the working device 50 selects camera identification information in a camera selection field 811 and selects a file name in a file selection field 812. This causes the second reception unit 270 to receive information indicating the contents of these selection operations. The display processing unit 280 reads out a file specified based on the information received by the second reception unit 270, and performs processing to display the deviation degree information and overall image 710 information stored in the file in the deviation degree display field 820 and overall image display field 840, respectively, as an update processing of the monitoring screen 800.

[0084] In addition, an example is shown in which the display processing unit 280 reads out the belt shot image 310 (moving image) stored in a file identified by selections in the camera selection field 811 and the file selection field 812, and performs processing to display it in the moving image display field 860 as an update process of the monitoring screen 800. FIG. 8B is a diagram showing an example of the monitoring screen 800 in a state where a file is selected.

[0085] In this embodiment, a graph showing the relationship between the frame number and belt length and the deviation degree is displayed as deviation degree information in deviation degree display field 820, as in the example shown in Fig. 6. The inspector refers to the deviation degree displayed in deviation degree display field 820 and inputs the frame number of the frame image to be confirmed (for example, a frame image expected to include a non-steady part) in frame number input field 830. Fig. 8C is a diagram showing an example of a monitoring screen 800 in a state in which the frame number has been specified in this manner.

[0086] In this embodiment, an example is shown in which the display processing unit 280 performs processing to update the monitoring screen 800, for displaying a frame 841, which is superimposed on the entire image 710, to draw attention to an area including a divided image to which the frame number input in the frame number input field 830 has been assigned.

[0087] Furthermore, in this embodiment, a case is illustrated in which a divided image to which a frame number input in the frame number input field 830 has been assigned and a divided image to which a frame number obtained by ±m from the frame number has been assigned are included within the frame 841. Here, m is a positive integer, and in FIG. 8C, a case is illustrated in which m is 2. Note that m may be 0 (zero). In this case, only the divided image to which the frame number input in the frame number input field 830 has been assigned is included within the frame. In this embodiment, the frame 841 is an example of attention area information for drawing attention to a partial area of ​​the overall image 710.

[0088] However, attention area information for drawing attention to a partial area of ​​the overall image 710 is not limited to the frame 841. For example, in addition to or instead of displaying the frame 841, the density of the divided images other than the divided images within the frame 841 (five divided images in the example shown in FIG. 8C ) may be lowered to draw attention to a partial area of ​​the overall image 710.

[0089] Also, attention area information (frame 841 in this embodiment) may be displayed without using the frame number input in frame number input field 830. For example, an inspector may be allowed to specify a position on the graph displayed in deviation display field 820. In this case, the frame number corresponding to the position specified by the inspector may be used in place of the frame number input in frame number input field 830.

[0090] Also, the attention area information (frame 841 in this embodiment) may be displayed without being specified by the inspector. For example, the display processing unit 280 may display the attention area information (frame 841 in this embodiment) as an area to draw attention to, which includes a divided image to which a frame number corresponding to the maximum deviation degree among the deviation degrees obtained when the belt 11 goes around the conveying path of the belt conveyor 10 is assigned. In this case, the deviation degree (graph 610) may not be displayed in the deviation degree display field 820 (for example, the monitoring screen 900 may not have the deviation degree display field 820). Also, for example, the belt conveyor monitoring device 40 may automatically specify, as an image of an area including the endless portion 330, the belt photographed image 310 and the projectively transformed image 420 to which a frame number corresponding to the maximum deviation degree among the deviation degrees obtained when the belt 11 goes around the conveying path of the belt conveyor 10 is assigned. In this case, the belt conveyor monitoring device 40 may automatically identify the position of the endless section 330 by determining how far the belt photographed image 310 including the identified endless section 330 and the post-projection transformation image 420 are from a reference position in the traveling direction of the belt 11.

[0091] As described above, in this embodiment, the display processing unit 280 performs processing for displaying attention area information for drawing attention to an area including a divided image to which a frame number selected based on the deviation is assigned. However, this is not necessarily required. For example, a GUI (Graphical User Interface) for an inspector to specify a divided image included in the overall image 710 displayed in the overall image display field 840 may be provided. In this case, when one of the divided images included in the overall image 710 is specified by the inspector, an image obtained by enlarging the divided image may be displayed on the overall image 710 to draw attention to the divided image.

[0092] Also, in this embodiment, a case is exemplified in which the display processing unit 280 reads out the frame image of the frame number input in the frame number input field 830 out of the belt photographed images 310 (frame images) stored in a file specified by the selection in the camera selection field 811 and the file selection field 812 as a designated frame image, and performs processing to display it in the designated frame image display field 851 in the frame image display field 850, as an update processing of the monitoring screen 800. Also, in this embodiment, a case is exemplified in which the display processing unit 280 reads out the frame image immediately before the designated frame image as a previous frame image, and performs processing to display it in the previous frame image display field 852 in the frame image display field 850, as an update processing of the monitoring screen 800. Also, in this embodiment, a case is exemplified in which the display processing unit 280 reads out the frame image immediately before the designated frame image as a subsequent frame image, and performs processing to display it in the subsequent frame image display field 853 in the frame image display field 850, as an update processing of the monitoring screen 800.

[0093] The output unit 290 outputs, as screen information, information necessary for the working device 50 to display, on a computer display, the updated monitoring screen 800 updated by the update process of the monitoring screen 800 performed by the display processing unit 280 as described above.

[0094] In the present embodiment, the case where the monitoring screen 800 is displayed on a computer display provided in the working device 50 or a computer display connected to the working device 50 has been exemplified. However, this is not necessarily the case. For example, the belt conveyor monitoring device 40 may display the monitoring screen 800 on a computer display. In this case, an operation on the monitoring screen 800 is performed by an inspector of the belt conveyor monitoring device 40. In addition, the second receiving unit 270 receives information indicating the content of an operation on the monitoring screen 800 performed by the inspector of the belt conveyor monitoring device 40.

[0095] <Flowchart> Next, an example of a belt conveyor monitoring method performed using the belt conveyor monitoring device 40 will be described with reference to the flowchart of FIG. First, in step S901, the acquisition unit 210 acquires the belt photographed image 310. For ease of explanation, a case will be exemplified in which the acquisition unit 210 acquires the belt photographed image 310 captured at a predetermined frame rate during the period in which the belt 11 makes one revolution around the conveying path of the belt conveyor 10, and then the processing from step S902 onward is performed.

[0096] Next, in step S902, the first reception unit 220 judges whether or not the first point 411, the second point 412, the third point 413, and the fourth point 414 selected from the belt photographed image 310 are specified. If the result of this judgment is that the first point 411, the second point 412, the third point 413, and the fourth point 414 are specified (YES in step S902), the process of step S903 is not performed and the process of step S904 described below is performed. On the other hand, if the first point 411, the second point 412, the third point 413, and the fourth point 414 are not specified (NO in step S902), the process of step S903 is performed.

[0097] In step S903, the display processing unit 280 creates a belt display screen that is a screen that displays information including the belt photographed image 310. The output unit 290 outputs information required for the working device 50 to display the belt display screen on a computer display as screen information to the working device 50. The working device 50 displays the belt display screen on a computer display based on the screen information. The first receiving unit 220 receives information on the positions of the first point 411, the second point 412, the third point 413, and the fourth point 414 designated by the inspector of the working device 50 from the belt photographed image 310 displayed on the belt display screen. Then, the process of step S904 is performed.

[0098] In step S904, the modification unit 230 performs projective transformation on a quadrangular region having vertices at the first point 411, the second point 412, the third point 413, and the fourth point 414 so that the quadrangular region becomes a rectangular image of a predetermined size, thereby generating a post-projective transformation image 420. The modification unit 230 performs this for each of the belt photographed images 310 (frame images) acquired in step S901. Then, the modification unit 230 assigns to each post-projective transformation image 420 the camera identification information, frame number, and shooting time assigned to the belt photographed image 310 (frame image) from which the post-projective transformation image 420 was created.

[0099] Next, in step S905, the image processing unit 240 creates a background image 510 for each of the projectively transformed images 420 created in step S904 using n projectively transformed images 420a to 420c created in step S904 from the belt photographed images 310 taken n frames before, n-1 frames before, . . . , 1 frame before the belt photographed image 310 from which the projectively transformed image 420 was created. Then, the image processing unit 240 creates a foreground image 520 by a background difference method using the projectively transformed image 420 and the background image 510 created for the projectively transformed image 420. Then, the image processing unit 240 assigns to each foreground image 520 the camera identification information, frame number, and shooting time assigned to the projectively transformed image 420 from which the foreground image 520 was created.

[0100] Next, in step S906, calculation unit 250 calculates the sum of the areas of black regions (blobs) in foreground images 520 as the deviation degree for each of foreground images 520 created in step S905. Then, calculation unit 250 assigns to each deviation degree the camera identification information, frame number, and shooting time assigned to foreground image 520 from which the deviation degree was calculated.

[0101] Next, in step S907, the creation unit 260 creates, as divided images, rectangular images obtained by extracting a portion of the projectively transformed image 420 so that no overlapping area is included between two projectively transformed images 420 that are adjacent to each other in the shooting order (frame number) for each of the projectively transformed images 420. At this time, the creation unit 260 makes sure that the images (divided images) extracted from each of the projectively transformed images 420 have the same size.

[0102] Next, in step S908, the creating unit 260 creates an entire image 710 by arranging the multiple divided images created in step S907 in the order of shooting (in the order of frame numbers).

[0103] Next, in step S909, creation unit 260 creates a set of information for the period during which belt 11 rotates, including belt photographed image 310 acquired in step S901, post-projection transformed image 420 created in step S904, foreground image 520 created in step S905, the deviation calculated in step S906, and overall image 710 created in step S908, as data in a single file.

[0104] Next, in step S910, the display processing unit 280 creates an initial state monitoring screen 800. The output unit 290 outputs information necessary for the operating device 50 to display the initial state monitoring screen 800 on a computer display as screen information to the operating device 50. The operating device 50 displays the monitoring screen 800 on the computer display based on the screen information (see FIG. 8A).

[0105] Next, in step S911, second reception unit 270 waits until the inspector selects (specifies) camera identification information for camera selection field 811 and selects (specifies) a file name for file selection field 812. When the inspector selects (specifies) camera identification information for camera selection field 811 and selects (specifies) a file name for file selection field 812 (YES in step S911), the process of step S912 is performed.

[0106] In step S912, the second reception unit 270 receives information indicating the content of the selection (designation) determined to have been made in step S911. Next, in step S813, the display processing unit 280 reads out the file specified based on the information received in step S912, and performs processing for displaying the deviation degree information and the overall image 710 information stored in the file in the deviation degree display field 820 and the overall image display field 840, respectively, as an update processing of the monitoring screen 800. The output unit 290 outputs, as screen information, information required for the maintenance device 50 to display the updated monitoring screen 800 updated by the update processing of the monitoring screen 800 on a computer display. The maintenance device 50 displays the updated monitoring screen 800 on the computer display based on the screen information (see FIG. 8B).

[0107] Next, in step S914, second reception unit 270 waits until a frame number is input into frame number input field 830. When a frame number is input into frame number input field 830 (YES in step S914), the process of step S915 is performed.

[0108] In step S915, the display processing unit 280 performs processing to update the monitoring screen 800, for displaying a frame 841, which is used to draw attention to an area including a divided image to which the frame number input in the frame number input field 830 has been assigned, superimposed on the entire image 710. The display processing unit 280 also performs processing to read out the frame image of the frame number input in the frame number input field 830 as a designated frame image, and display it in a designated frame image display field 851 in the frame image display field 850, as part of the update processing of the monitoring screen 800. The display processing unit 280 also performs processing to read out the frame images one frame before and one frame after the designated frame image as a previous frame image and a subsequent frame image, respectively, and display them in a previous frame image display field 852 and a subsequent frame image display field 853 in the frame image display field 850, as part of the update processing of the monitoring screen 800. Furthermore, the display processing unit 280 reads out the belt photographed image 310 (moving image) stored in the file created in step S909, and performs processing for displaying it in the moving image display field 860 as an update process for the monitoring screen 800.

[0109] The output unit 290 outputs, as screen information, information necessary for the maintenance device 50 to display on a computer display the updated monitoring screen 800 that is updated by the update process of the monitoring screen 800. The maintenance device 50 displays the updated monitoring screen 800 on the computer display based on the screen information (see FIG. 8C). When the process of step S915 ends, the process according to the flowchart of FIG. 9 ends.

[0110] <Summary> As described above, in this embodiment, the belt conveyor monitoring device 40 changes the area including the belt 11 in the belt photographed image 310 so that the area including the belt 11 approaches a state photographed from a direction facing the belt 11, and performs processing for extracting a characteristic area from the image of the area including the belt 11 after the change. Therefore, it is possible to change the image of the area including the belt 11 so as to improve the extraction accuracy of the characteristic area, and then perform processing for extracting the characteristic area. Therefore, it is possible to monitor the state of the belt 11 based on the image photographed by the photographing device 30 without accurately adjusting the position and photographing direction of the photographing device 30. This makes it possible to easily monitor the state of the belt 11 of the belt conveyor 10 based on the photographed image.

[0111] Furthermore, in this embodiment, the belt conveyor monitoring device 40 changes the area including the belt 11 in the belt photographed image 310 so that the area including the belt 11 in the belt photographed image 310 is photographed from a direction facing the belt 11. Therefore, it is possible to further improve the extraction accuracy of the feature area included in the image of the area including the belt 11.

[0112] Furthermore, in this embodiment, the belt conveyor monitoring device 40 performs projective transformation on the area including the belt 11 in the belt photographed image 310 so that the shape of the area including the belt 11 in the belt photographed image 310 becomes a rectangular or square image of a predetermined size. Therefore, the extraction accuracy of the feature area included in the image of the area including the belt 11 can be improved without using a special algorithm.

[0113] Furthermore, in this embodiment, the belt conveyor monitoring device 40 performs projective transformation of a quadrangular area having vertices of the first point 411, the second point 412, the third point 413, and the fourth point 413 selected from the belt photographed image 310 into a rectangular or square image of a predetermined size. Therefore, even if the installation position of the photographing device 30, the photographing conditions, and the photographed subject (belt conveyor) are changed, it is possible to prevent the area of ​​the belt 11 from being not included in the image after projective transformation (image after projective transformation 420).

[0114] In addition, in this embodiment, the belt conveyor monitoring device 40 accepts designation by an inspector (user) of the first point 411, the second point 412, the third point 413, and the fourth point 414. Therefore, it is possible to reliably monitor the area of ​​the belt 11 that the inspector wishes to focus on.

[0115] In this embodiment, the belt conveyor monitoring device 40 acquires belt photographed images 310 captured by the portable photographing device 30. Since the photographing device 30 is a portable photographing device, the photographing device 30 can also be used to capture belt photographed images of a belt conveyor other than the belt conveyor 10. In other words, it is not necessary to install a photographing device for each belt conveyor.

[0116] Furthermore, in this embodiment, the belt conveyor monitoring device 40 calculates an evaluation index for evaluating the amount of characteristic areas included in the area of ​​the belt 11 based on the result of processing for extracting characteristic areas from an image of the area including the changed belt 11 (for example, the post-projection transformation image 420). Therefore, it is possible to quantify the amount of characteristic areas included in the area of ​​the belt 11.

[0117] Furthermore, in this embodiment, the belt conveyor monitoring device 40 calculates the relationship between the evaluation index based on the result of processing for extracting a feature area from an image of an area including the changed belt 11 (for example, the image after projective transformation 420) and information for identifying the position of the belt 11 included in the image subjected to the processing. Therefore, the inspector can easily understand which part of the belt 11 each evaluation index corresponds to.

[0118] Furthermore, in this embodiment, the belt conveyor monitoring device 40 calculates a plurality of divided images 721-723, which are images in each divided area when the area of ​​one revolution of the belt 11 is divided in the traveling direction of the belt 11, based on an image of the area including the changed belt 11 (for example, the image after projective transformation 420). Therefore, the image of the area of ​​one revolution of the belt 11 can be made in a state that is easy for the inspector to view.

[0119] In addition, in this embodiment, the belt conveyor monitoring device 40 creates an entire image 710, which is an image in which the multiple divided images 721 to 723 are arranged in the order in which they were photographed. Therefore, it is possible to make it easy for an inspector to get a bird's-eye view of the entire image of one revolution of the belt 11.

[0120] Furthermore, in this embodiment, the belt conveyor monitoring device 40 performs processing for displaying, on the display device, attention area information for drawing attention to a partial area of ​​the entire image 710 by superimposing it on the entire image 710. Therefore, the inspector can easily recognize which part of the entire image 710 contains the information that should be noted during monitoring.

[0121] In addition, in this embodiment, the belt conveyor monitoring device 40 receives an input operation by an inspector (user) specifying a divided image, and determines an area to be focused on based on the received input operation. Therefore, the inspector can easily recognize which part of the entire image 710 is the area to which the inspector wants to focus.

[0122] Furthermore, in this embodiment, the belt conveyor monitoring device 40 calculates an evaluation index for evaluating the amount of characteristic areas included in the area of ​​the belt 11 based on the result of processing for extracting characteristic areas from an image of the area including the changed belt 11 (for example, the post-projection transformation image 420), and determines an area to be noted based on the evaluation index. Therefore, for example, an area with a large amount of characteristic areas can be determined as an area to be noted.

[0123] In addition, in this embodiment, the belt conveyor monitoring device 40 performs image processing using a background subtraction method as a process for extracting the non-steady parts. Therefore, it is possible to improve the extraction accuracy of the non-steady parts of the belt 11 without using a special algorithm.

[0124] (Other embodiments) The above-described embodiment of the present invention can be realized by a computer executing a program. A computer-readable recording medium on which the program is recorded and a computer program product such as the program can also be applied as an embodiment of the present invention. Examples of the recording medium that can be used include a flexible disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a magnetic tape, a non-volatile memory card, and a ROM. Furthermore, the above-described embodiments of the present invention are merely examples of the implementation of the present invention, and the technical scope of the present invention should not be interpreted as being limited by these. In other words, the present invention can be implemented in various forms without departing from its technical concept or main features.

[0125] The disclosure of the above embodiment can be, for example, as follows. [Disclosure 1] An acquisition unit that acquires a photographed image including a belt of a belt conveyor in operation; a change unit that changes an area including the belt in the captured image so that the area including the belt in the captured image approaches a state in which the area is captured from a direction facing the belt; an image processing unit that performs processing to extract a feature region included in the belt region from the image of the belt region after the image has been changed by the change unit; A belt conveyor monitoring device comprising: [Disclosure 2] The belt conveyor monitoring device described in Disclosure 1, wherein the modification unit modifies an area including the belt in the captured image so that the area including the belt in the captured image appears as if it were photographed from a direction facing the belt. [Disclosure 3] The belt conveyor monitoring device according to Disclosure 1 or 2, wherein the modification unit performs projective transformation of an area including the belt in the captured image so that the shape of the area including the belt in the captured image becomes a rectangle or square of a predetermined size. [Disclosure 4] the modification unit performs projective transformation of a quadrangular region having vertices of a first point, a second point, a third point, and a fourth point selected from the captured image, into a rectangular or square image of a predetermined size; the first point and the second point are spaced apart from each other in a traveling direction of the belt and are points at positions corresponding to one end of the belt in a width direction, The belt conveyor monitoring device according to Disclosure 3, wherein the third point and the fourth point are spaced apart from each other in the traveling direction of the belt and are points at positions corresponding to the other end of the belt in the width direction. [Disclosure 5] The belt conveyor monitoring device according to Disclosure 4, further comprising a first reception unit that receives user designation of the first point, the second point, the third point, and the fourth point. [Disclosure 6] The belt conveyor monitoring device according to any one of Disclosures 1 to 5, wherein the captured image is an image captured by a portable imaging device. [Disclosure 7] The belt conveyor monitoring device according to any one of Disclosures 1 to 6, further comprising a calculation unit that calculates an evaluation index for evaluating the amount of the characteristic region contained in the belt region based on a result of processing by the image processing unit. [Disclosure 8] The belt conveyor monitoring device described in Disclosure 7, wherein the calculation unit calculates a relationship between the evaluation index based on a result of processing by the image processing unit and information for identifying the position of the belt contained in the image that was the subject of the processing. [Disclosure 9] The belt conveyor monitoring device according to any one of Disclosures 1 to 8, further comprising a creation unit that creates a plurality of divided images, which are images of each divided area when an area of ​​one revolution of the belt is divided in the traveling direction of the belt, based on an image of the area including the belt after it has been changed by the change unit. [Disclosure 10] The belt conveyor monitoring device according to Disclosure 9, wherein the creation unit further creates an overall image in which the plurality of divided images are arranged in the order in which they were photographed. [Disclosure 11] The belt conveyor monitoring device according to Disclosure 10, further comprising a display processing unit that performs processing for displaying the entire image on a display device. [Disclosure 12] The belt conveyor monitoring device described in Disclosure 11, wherein the display processing unit performs processing to superimpose attention area information, which is information for drawing attention to a partial area of ​​the entire image, on the entire image and display it. [Disclosure 13] a second reception unit that receives an input operation by a user to specify the divided image, The belt conveyor monitoring device according to Disclosure 12, wherein the area to be focused on is determined based on an input operation accepted by the second accepting unit. [Disclosure 14] a calculation unit that calculates an evaluation index for evaluating an amount of the characteristic region included in the region of the belt based on a result of processing by the image processing unit, The belt conveyor monitoring device according to Disclosure 12 or 13, wherein the area to be focused on is determined based on the evaluation index. [Disclosure 15] The belt conveyor monitoring device according to any one of Disclosures 1 to 14, wherein the processing by the image processing unit includes image processing using a background subtraction method. [Disclosure 16] The belt conveyor monitoring device according to any one of Disclosures 1 to 15, wherein the characteristic region is a region that is a candidate for at least one of an endless portion and an abnormal portion of the belt. [Disclosure 17] An acquisition step of acquiring a photographed image including a belt of a belt conveyor in operation; a modifying step of modifying an area including the belt in the captured image so that the area including the belt in the captured image approaches a state in which the area is captured from a direction facing the belt; an image processing step of performing processing for extracting a feature region included in the belt region from an image of the region including the belt after the modification step; a display step of displaying a position of the characteristic area on the belt on a monitoring screen; A belt conveyor monitoring method comprising: [Disclosure 18] A program for causing a computer to function as each part of the belt conveyor monitoring device according to any one of Disclosures 1 to 16. [Explanation of symbols]

[0126] 10. Conveyor Belt 11 Belt 12a~12m pulley 13 Obstacles 20(20a~20d) Storage device 30 Imaging Equipment 40 Belt conveyor monitoring device 50 Work Equipment 60 Network 210 Acquisition Department 220 First Reception Section 230 Changes 240 Image Processing Unit 250 Calculation Section 260 Creation Department 270 Second Reception Section 280 Display Processing Unit 290 Output section 310(310a~310c) Belt photo 320 Obstacle Shadow 330 Endless Division 340 Damaged area 411~413 Vertices of a quadrilateral 420(420a~420c) Image after projective transformation 510 Background Image 520 Foreground Image 521a~521c Noise 610 Graph showing deviation 710 Full image 721~723 Split image 800 monitoring screen 810 Side menu column 811 Camera selection column 812 File selection field 813 Download section 813a~913f Download button 820 Deviation degree display field 830 Frame number input field 840 Full image display field 850 frame image display area 851 Specified frame image display field 852 Previous frame image display field 853 Rear frame image display field 860 Video display column

Claims

1. An acquisition unit that acquires a photographed image including a belt of a belt conveyor in operation; a change unit that changes an area including the belt in the captured image so that the area including the belt in the captured image approaches a state in which the area is captured from a direction facing the belt; an image processing unit that performs processing to extract a feature region included in the belt region from the image of the belt region after the image has been changed by the change unit; A belt conveyor monitoring device comprising:

2. The belt conveyor monitoring device according to claim 1 , wherein the change unit changes an area including the belt in the captured image so that the area including the belt in the captured image appears as if it were captured from a direction facing the belt.

3. 3. The belt conveyor monitoring device according to claim 1, wherein the modification unit performs projective transformation of an area including the belt in the captured image so that the shape of the area including the belt in the captured image becomes a rectangle or a square of a predetermined size.

4. the modification unit performs projective transformation of a quadrangular region having vertices of a first point, a second point, a third point, and a fourth point selected from the captured image, into a rectangular or square image of a predetermined size; the first point and the second point are spaced apart from each other in a traveling direction of the belt and are points at positions corresponding to one end of the belt in a width direction, 4. The belt conveyor monitoring device according to claim 3, wherein the third point and the fourth point are spaced apart from each other in the traveling direction of the belt and are points at positions corresponding to the other end of the belt in the width direction.

5. The belt conveyor monitoring device according to claim 4 , further comprising a first receiving unit that receives designation by a user of the first point, the second point, the third point, and the fourth point.

6. The belt conveyor monitoring device according to claim 1 or 2, wherein the captured image is captured by a portable imaging device.

7. The belt conveyor monitoring device according to claim 1 , further comprising a calculation unit that calculates an evaluation index for evaluating an amount of the characteristic region included in the region of the belt based on a result of the processing by the image processing unit.

8. The belt conveyor monitoring device according to claim 7 , wherein the calculation unit calculates a relationship between the evaluation index based on a result of processing by the image processing unit and information for identifying a position of the belt contained in the image that was the subject of the processing.

9. The belt conveyor monitoring device according to claim 1 or 2, further comprising a creation unit that creates a plurality of divided images, which are images of each divided area when an area of ​​one circumference of the belt is divided in the traveling direction of the belt, based on an image of the area including the belt after it has been changed by the change unit.

10. The belt conveyor monitoring device according to claim 9 , wherein the creation unit further creates an entire image by arranging the plurality of divided images in the order in which they were photographed.

11. The belt conveyor monitoring device according to claim 10 , further comprising a display processing unit that performs processing for displaying the entire image on a display device.

12. The belt conveyor monitoring device according to claim 11 , wherein the display processing unit performs processing for displaying attention area information, which is information for drawing attention to a partial area of ​​the entire image, superimposed on the entire image.

13. a second reception unit that receives an input operation by a user to specify the divided image, The belt conveyor monitoring device according to claim 12, wherein the area to be focused on is determined based on an input operation accepted by the second accepting unit.

14. a calculation unit that calculates an evaluation index for evaluating an amount of the characteristic region included in the region of the belt based on a result of processing by the image processing unit, The belt conveyor monitoring device according to claim 12 , wherein the area to be focused on is determined based on the evaluation index.

15. The belt conveyor monitoring device according to claim 1 or 2, wherein the processing by the image processing unit includes image processing using a background subtraction method.

16. The belt conveyor monitoring device according to claim 1 or 2, wherein the characteristic region is a region that is a candidate for at least one of an endless portion and an abnormal portion of the belt.

17. An acquisition step of acquiring a photographed image including a belt of a belt conveyor in operation; a modifying step of modifying an area including the belt in the captured image so that the area including the belt in the captured image approaches a state in which the area is captured from a direction facing the belt; an image processing step of performing processing for extracting a feature region included in the belt region from an image of the region including the belt after the modification step; a display step of displaying a position of the characteristic area on the belt on a monitoring screen; A belt conveyor monitoring method comprising:

18. A program for causing a computer to function as each unit of the belt conveyor monitoring device according to claim 1 or 2.

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