Disorderly winding detection device and method

Abstract

Provided are a miswinding detection device and a miswinding detection method that make it possible to quickly and accurately detect miswinding. A miswinding detection device (1) has an outline detection unit (12) that detects the outline of a wire rope (3) in the direction of the rotational axis of a drum (2) in a captured image of the wire rope (3) as wound on the drum (2) and a determination unit (15) that calculates the degree of change in the detected outline in the radial direction of the drum (2) and determines miswinding of the wire rope (3) on the basis of the magnitude of the calculated degree of change.

Description

[Technical Field]

[0001] The present invention relates to a device and a method for detecting irregular winding. [Background technology]

[0002] When the wire rope wound around the winch drum is not aligned, it is called a "disarray." Because the wire rope that lifts the crane's load is under a large amount of tension, continuing operation with a disarray can cause damage to the wire rope. Therefore, technologies have been proposed to prevent or detect disarray.

[0003] The winch equipment disclosed in Patent Document 1 synchronizes the movement of the winding guide with the movement of the winch so that the wire rope is wound from a direction perpendicular to the rotation axis of the drum.

[0004] The winch disclosed in Patent Document 2 has a limit switch provided near the wire rope wound around the drum, and detects irregular winding when the wire rope comes into contact with the limit switch. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-87763 [Patent Document 2] Japanese Utility Model Application Publication No. 6-27873 Summary of the Invention [Problem to be solved by the invention]

[0006] The winch equipment disclosed in the above Patent Document 1 is provided with a mechanism that makes it difficult for irregular winding to occur. However, this equipment is not provided with a function for detecting when irregular winding has actually occurred.

[0007] The winch disclosed in Patent Document 2 detects the magnitude of the wire rope's deflection angle relative to the drum. However, this winch does not directly detect the occurrence of irregular winding on the drum. Furthermore, if the limit switch's tolerance range is too wide, the detection of irregular winding will be delayed, and if it is too narrow, irregular winding will be detected excessively, causing delays in work. Furthermore, irregular winding cannot be detected unless the wire rope touches the limit switch. In this case, it becomes difficult to detect irregular winding if the wire rope slackens in a direction other than the limit switch.

[0008] An object of the present invention is to provide a device and method for detecting irregular winding that can quickly and accurately detect the occurrence of irregular winding. [Means for solving the problem]

[0009] One aspect of the irregular winding detection device according to the present invention is: a contour detection unit that detects a contour of the wire rope extending in a rotation axis direction of the drum in a captured image of the wire rope wound around the drum; a determination unit that calculates a degree of change in the detected contour in the radial direction of the drum and determines whether or not irregular winding of the wire rope has occurred based on the magnitude of the calculated degree of change; It has.

[0010] One aspect of the method for detecting irregular winding according to the present invention is to A method for detecting irregular winding executed by a random winding detection device, a contour detection step of detecting a contour of the wire rope extending in a rotation axis direction of the drum in a captured image of the wire rope wound around the drum; a determination step of calculating a degree of change in the detected contour in the radial direction of the drum, and determining whether or not irregular winding of the wire rope has occurred based on the magnitude of the calculated degree of change; Includes: [Effects of the Invention]

[0011] According to the present invention, the occurrence of irregular winding can be detected quickly and accurately. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic diagram showing the functional configuration of a random winding detection device according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a diagram showing an example of an image captured by the imaging device. [Figure 3] FIG. 3 is a diagram showing an example of a change in luminance of pixels on a perpendicular line. [Figure 4] FIG. 4 is a diagram showing how the scanning window is scanned. [Figure 5] Fig. 5A is a diagram showing a bounding box, and Fig. 5B is a diagram showing an example of a plurality of bounding boxes generated from the same partial area PA with different rotation angles. [Figure 6] FIG. 6 is a block diagram showing the hardware configuration of the irregular winding detection device of FIG. [Figure 7] FIG. 7 is a flowchart showing the operation of the irregular winding detection device of FIG. [Figure 8] 8A to 8F are schematic diagrams showing the movement of the scanning window and the bounding box that is generated. [Figure 9] 9A and 9B are schematic diagrams showing how irregular winding occurs. [Figure 10] FIG. 10 is a schematic diagram showing the functional configuration of a random winding detection device according to the second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings, in which the same or equivalent parts are designated by the same reference numerals.

[0014] (Embodiment 1) First, a first embodiment of the present invention will be described. As shown in Fig. 1, the irregular winding detection device 1 according to this embodiment detects irregular winding, in which the wire rope 3 wound around the drum 2 of a winch is not aligned. The wire rope 3 wound around the drum 2 passes through a guide sheave and a top sheave (not shown) and extends to a hook that suspends a load. In Fig. 1, the drum 2 is shown in cross section.

[0015] [Overall configuration] The irregular winding detection device 1 includes an imaging device 10 as an imaging unit, and an image processing device 20 that performs image processing on image data captured by the imaging device 10 to detect the occurrence of irregular winding.

[0016] [Imaging device] The imaging device 10 is disposed in a direction intersecting the rotation axis direction along which the rotation axis AX of the drum 2 extends. The imaging device 10 captures an image of the wire rope 3 wound around the drum 2. FIG. 2 shows an example of imaging data ID for this image. As shown in FIG. 2, the imaging field of view of the imaging device 10 includes the entire drum 2 around which the wire rope 3 is wound. However, this is not limited to this, and the imaging field of view of the imaging device 10 only needs to include the entire contour area CA extending in the direction of the rotation axis AX of the wire rope 3 wound around the drum 2.

[0017] In order to quickly detect irregular winding, it is desirable that the imaging field of view of the imaging data ID includes the winding position 4 of the drum 2 around which the wire rope 3 is wound. However, this is not limited to this, and the position of the imaging device 10 relative to the drum 2 is arbitrary.

[0018] The imaging device 10 captures a moving image of the wire rope 3 wound around the drum 2. At a frame rate of the moving image, for example, 30 frames of imaging data ID are generated per second. The imaging device 10 may also capture still images of imaging data ID at regular intervals. For example, it can be set to capture a fixed number of frames, for example, four frames of imaging data, during one rotation of the drum 2.

[0019] As shown in FIG. 2, the imaging data ID is data of an overall rectangular image composed of multiple pixels arranged on a two-dimensional plane. In the imaging data ID, the axis extending horizontally is the H axis, and the axis extending vertically is the V axis. In this embodiment, the positional relationship between the drum 2 and the imaging device 10 is fixed so that the direction of the rotation axis AX of the drum 2 coincides with the H axis. Since the positional relationship between them is fixed, the positions of the flanges 2a provided on both ends of the rotation axis AX of the drum 2 in the imaging data ID are known. Note that there may be a slight angular deviation between the direction of the rotation axis AX of the drum 2 and the H axis. In the following image processing, it is assumed that this angular deviation is calibrated.

[0020] The image data ID may be color image data or black and white image data, as long as it is image data that can detect the contour area CA of the wire rope 3 wound around the drum 2 based on the change in brightness.

[0021] [Image processing device] Returning to FIG. 1, the image processing device 20 includes an imaging data acquisition unit 11, a contour detection unit 12, a partial region extraction unit 13, a bounding box generation unit 14, a determination unit 15, and a notification unit 16.

[0022] [Imaging data acquisition section] As shown in Fig. 2, the imaging data acquisition unit 11 acquires imaging data IDs of images captured by the imaging device 10. As described above, if the frame rate of moving images captured by the imaging device 10 is 30 frames per second, the imaging data acquisition unit 11 acquires imaging data IDs each time the drum 2 rotates by a certain angle, for example, 90 degrees, with some overlapping during one rotation of the drum 2. This allows a certain number of imaging data IDs, for example, four, to be acquired during one rotation of the drum 2. Furthermore, if the imaging device 10 is configured to capture still images, the imaging data acquisition unit 11 may send imaging commands to the imaging device 10 at regular intervals and receive imaging data IDs from the imaging device 10.

[0023] The imaging data acquisition unit 11 does not have to acquire imaging data IDs in synchronization with the rotation of the drum 2. For example, when the drum 2 rotates at the maximum rotation speed, imaging data IDs may be acquired at a constant cycle at a speed that acquires multiple imaging data IDs that partially overlap each other and cover the entire circumference of the drum 2 during one rotation of the drum 2.

[0024] [Contour detection section] As shown in FIG. 2, the contour detection unit 12 detects a contour area CA extending in the direction of the rotation axis AX of the wire rope 3 wound around the drum 2 from the image data captured by the imaging device 10. The contour area CA is an example of the contour of the wire rope 3 that is the target of the irregular winding detection process. In this embodiment, the contour area CA includes pixels corresponding to the coordinate positions of the contour of the wire rope 3 in the image data of the drum 2 around which the wire rope 3 is wound, but does not include pixels that do not correspond to the coordinate positions of the contour. Therefore, the contour area CA extends overall in the direction of the rotation axis AX of the drum 2 (H-axis direction), but in detail has a non-linear shape like a wave shape (which may also be called a bellows shape) in which the coordinate position in the radial direction of the drum (V-axis direction) fluctuates up and down (see FIG. 4, etc.). The contour detection unit 12 detects the contour area CA as follows. First, the contour detection unit 12 determines a reference line RL extending horizontally in the image data ID, i.e., in the H-axis direction. The position of the reference line RL on the V axis is arbitrary, but it must be a position that is clearly outside the contour area CA. For example, the reference line RL can be a line extending in the H axis direction at a position 2 / 3 of the total width of the imaging data ID in the V axis direction.

[0025] Next, the contour detection unit 12 determines a perpendicular line VL extending vertically from the reference line RL in the image data ID, as shown in Fig. 2. Then, the contour detection unit 12 determines the change in brightness of each pixel on the perpendicular line VL. As shown in Fig. 2, the perpendicular line VL extends between the rope area WA of the wire rope 3 and the background area BA on the back side of the drum 2.

[0026] As shown in FIG. 3, in the image data ID, the rope area WA of the wire rope 3 has high brightness, while the background area BA has low brightness. Furthermore, the brightness value changes suddenly in the contour area CA of the wire rope 3. The contour detection unit 12 detects the contour area CA of the wire rope 3 based on this change in brightness. For example, as shown in FIG. 3, a set of pixels having a brightness value between a higher brightness threshold BH and a lower brightness threshold BL can be detected as the contour area CA.

[0027] The contour detection unit 12 draws perpendicular lines VL from each pixel on the reference line RL in the image data ID and detects a contour area CA based on the brightness change at each perpendicular line VL. This generates a contour area CA that extends in the direction of the rotation axis AX of the drum 2.

[0028] [Partial region extraction part] As shown in FIG. 4, the partial region extraction unit 13 defines a scanning window W having a certain length in the direction of the rotation axis AX for the contour region CA detected by the contour detection unit 12. In this embodiment, if the number of pixels in the image data ID corresponding to the diameter of the wire rope 3 is k, the length of the scanning window W is set to 2k. The partial region extraction unit 13 extracts a partial region PA included in the section corresponding to the scanning window W from the contour region CA. The partial region extraction unit 13 scans this scanning window W in the direction of the rotation axis AX. For example, the scanning window W is shifted one pixel at a time from the left end of the contour region CA. Each time the scanning window W is shifted, the partial region extraction unit 13 extracts a partial region PA included in the section corresponding to the scanning window W.

[0029] [Bounding box generation] Each time the partial area extraction unit 13 extracts a partial area PA, the bounding box generation unit 14 generates a minimum bounding box MVB, which has the smallest area, from among the bounding boxes VB, which are rectangular and can be rotated within a two-dimensional plane of the image data ID, and which encompass the extracted partial area PA, as shown in FIGS. 5A and 5B. In this embodiment, the bounding box VB is a rectangle, with the length of the short side (the side extending vertically at the time of initial extraction) of the generated minimum bounding box MVB being a and the length of the long side (the side extending horizontally at the time of initial extraction) being b (b > a). A rectangle is an example of a standardized shape used to simplify the manner in which the outline area CA changes in the V-axis direction (corresponding to the radial direction of the drum 2). Using such a standardized shape simplifies the calculation of the degree of change in the outline area CA in the V-axis direction and the comparison with a reference value, thereby suppressing an increase in the hardware load of the image processing device 20 and easily ensuring the accuracy of random winding detection.

[0030] The bounding boxes VB generated for each partial area PA in a single extraction run have different angles (rotation angles θ) between the long side (side with length b) of the rectangle and the H-axis direction (the direction in which the outline area CA and partial area PA extend). Each of the bounding boxes VB encompasses the partial area PA without including any unnecessary surrounding areas. However, because the bounding boxes VB encompass the partial area PA, whose length in the H-axis direction is always constant (the length of the scanning window W is 2k), both the length a of the short side and the length b of the long side of the bounding box VB change with rotation (i.e., with changes in the rotation angle θ). As a result, the areas of the bounding boxes VB change with the rotation angle θ. The bounding box generation unit 14 selects the smallest bounding box MVB from among the bounding boxes VB whose areas change with the rotation angle θ.

[0031] [Judgment section] The determination unit 15 determines whether or not irregular winding has occurred in the wire rope 3 based on the area of ​​the minimum bounding box MVB generated by the bounding box generation unit 14. Here, the area of ​​the minimum bounding box MVB is a × b. The determination unit 15 determines that irregular winding has occurred in the wire rope 3 when a × b satisfies the following inequality. a×b>2×k×k The right side of this inequality is the area of ​​a rectangle whose horizontal length is the length of the scanning window W and whose vertical length is the diameter of the wire rope 3.

[0032] [Notification Department] When the determination unit 15 determines that the wire rope 3 is irregularly wound, the notification unit 16 notifies the operator that irregular winding has occurred. The notification unit 16 is equipped with an alarm, a warning light, or a display device, and, for example, sounds an alarm, lights or flashes a warning light, or displays on a display device that irregular winding has occurred. Instead of or in addition to issuing a notification, the notification unit 16 may issue a command to a control device (not shown) to stop the drum 2.

[0033] In this embodiment, when the state in which the determination unit 15 determines that the size of the minimum bounding box MVB exceeds 2×k×k continues for a certain period of time, the notification unit 16 notifies that a disorderly winding has occurred in the wire rope 3. However, the notification unit 16 may be configured to notify that a disorderly winding has occurred in the wire rope 3 when the determination unit 15 determines that a disorderly winding has occurred in the wire rope 3 even once.

[0034] [Hardware configuration] The irregular winding detection device 1 shown in FIG. 1 is realized, for example, by a computer having a hardware configuration shown in FIG. 6 executing a software program.

[0035] Specifically, the irregular winding detection device 1 comprises a CPU (Central Processing Unit) 21 that controls the entire device, a main memory unit 22 that operates as a work area for the CPU 21, an external memory unit 23 that stores the operating program of the CPU 21, a camera 24, a display 25, an audio output unit 26, and an internal bus 28 that connects these.

[0036] The CPU 21 is a processor (arithmetic device) that executes a software program (hereinafter simply referred to as a "program"). A program 29 is loaded into the main memory 22 from the external memory 23. The CPU 21 executes the program 29 stored in the main memory 22. This realizes the functions of the imaging data acquisition unit 11, the contour detection unit 12, the partial region extraction unit 13, the bounding box generation unit 14, the determination unit 15, and the notification unit 16.

[0037] The main memory unit 22 is composed of RAM (Random Access Memory) etc. A program 29 of the CPU 21 is loaded into the main memory unit 22 from the external memory unit 23. The main memory unit 22 is also used as a working area (temporary data storage area) for the CPU 21.

[0038] The external storage unit 23 is configured by a nonvolatile memory such as a flash memory, a hard disk, etc. The external storage unit 23 stores in advance a program 29 to be executed by the CPU 21.

[0039] The camera 24 captures images. The camera 24 can capture still images or moving images. The camera 24 corresponds to the imaging device 10.

[0040] The display 25 is a display device that displays images. The audio output unit 26 outputs audio. The display 25 and the audio output unit 26 implement the function of the notification unit 16.

[0041] [Operation of the irregular winding detection device] Next, the operation of the irregular winding detection device 1 according to the first embodiment of the present invention, i.e., the irregular winding detection process that realizes the irregular winding detection method, will be described. The process shown in the flowchart of Fig. 7 starts when winding of the wire rope 3 onto the drum 2 starts.

[0042] 7, first, the imaging data acquisition unit 11 acquires the imaging data ID of the image of the wire rope 3 wound around the drum 2 captured by the imaging device 10 (step S1; imaging data acquisition step). As a result, for example, the imaging data ID of the wire rope 3 wound around the drum 2 as shown in FIG.

[0043] Next, the contour detection unit 12 detects a contour area CA extending in the rotation axis direction of the wire rope 3 wound around the drum 2 from the imaging data ID acquired in step S1 (step S2; contour detection step). Here, for example, as shown in FIG. 2, a reference line RL is drawn for the imaging data ID, and perpendicular lines VL extending in the +V direction are drawn from each pixel on the reference line RL. Furthermore, based on the change in brightness on each perpendicular line VL (see FIG. 3), for example, the contour area CA of the wire rope 3 shown in FIG. 2 is detected.

[0044] Next, partial region extraction unit 13 sets the position of a scanning window W having a certain length in the direction of rotation axis AX for the contour region CA detected in step S2 (step S3; scanning window position setting step). In the first processing of step S3, partial region extraction unit 13 sets the scanning window W to the left end (furthest to the -H side) of contour region CA, as shown in Fig. 4. In step S3, partial region extraction unit 13 shifts the position of the scanning window W by one pixel in the +H direction each time the processing of step S3 is executed.

[0045] Subsequently, partial area extraction unit 13 extracts a partial area PA included in the section corresponding to the scanning window W from the contour area CA (step S4; partial area extraction step). Here, as shown in Fig. 4, the area of ​​the contour area CA that corresponds to the scanning window W is extracted as the partial area PA. In Fig. 4, the partial area PA is indicated by a thick solid line, and the contour area CA outside the partial area PA is indicated by a thick dotted line.

[0046] Next, the bounding box generation unit 14 generates a minimum bounding box MVB that contains the extracted partial region PA and has the smallest area among the bounding boxes VB, which are rectangles that can be rotated within a two-dimensional plane of the image data ID (step S5; minimum bounding box generation step). Here, as shown in FIG. 5A, the bounding box generation unit 14 generates multiple bounding boxes VB that contain the partial region PA and have different rotation angles θ relative to the H axis. Note that the bounding box VB is assumed to be the bounding box VB with the smallest area that contains the partial region PA at that angle θ. Furthermore, the bounding box generation unit 14 selects the bounding box VB with the smallest area as the minimum bounding box MVB from the bounding boxes VB with the smallest area at each angle θ.

[0047] Next, the determination unit 15 calculates the area of ​​the minimum bounding box MVB generated in step S4 (step S6), and determines whether or not irregular winding has occurred in the wire rope 3 based on the calculated area of ​​the minimum bounding box MVB (step S7; determination step). For example, as shown in FIG. 8A, when the contour of the wire rope 3 corresponding to the scanning window W is regular, the bounding box VB generated from the partial area PA is smallest at angle θ = 0, and the bounding box VB at θ = 0 is generated as the minimum bounding box MVB. The area of ​​this minimum bounding box MVB is less than or equal to the area of ​​the reference bounding box RVB having an area of ​​2 × k × k (an example of a reference area) to be compared. In this case, the determination unit 15 determines that irregular winding has not occurred in the wire rope 3.

[0048] If it is determined that no irregular winding has occurred (step S7; No), the image processing device 20 determines whether or not to end scanning of the scanning window W (step S11). When the +H end of the scanning window W reaches the +H end of the drum 2, it is determined that scanning should end. If scanning has not ended (step S11; No), the image processing device 20 returns to step S3.

[0049] After returning from step S11, the partial region extraction unit 13 sets the position of the scanning window W relative to the contour region CA detected in step S2 (step S3). In the second and subsequent processing of step S3, the partial region extraction unit 13 shifts the position of the scanning window W by one pixel in the +H direction from the current set position of the scanning window W. Next, the partial region extraction unit 13 extracts a partial region PA included in the section corresponding to the scanning window W from the contour region CA (step S4), and the bounding box generation unit 14 generates a minimum bounding box MVB (step S5). Furthermore, the determination unit 15 calculates the area of ​​the minimum bounding box MVB generated in step S4 (step S6), and determines whether or not irregular winding occurs in the wire rope 3 based on the calculated area (step S7). Furthermore, if the determination unit 15 determines that irregular winding does not occur (step S7; No), the image processing device 20 determines whether or not to end scanning of the scanning window W (step S11). If the scanning is not to be ended (step S11; No), the image processing device 20 returns to step S3.

[0050] In this way, unless the judgment unit 15 judges that irregular winding has occurred (step S7; No), steps S3 to S7 and S11 are repeated, a partial area PA is extracted from the contour area CA detected from the imaging data ID, the area of ​​the minimum bounding box MVB that contains the partial area PA is calculated, and the judgment as to whether irregular winding has occurred is repeated.

[0051] If the determination unit 15 determines that the random winding has occurred (step S7; Yes), the determination unit 15 stores the position of the scanning window W where the random winding has occurred and the number of consecutive occurrences of the random winding at the position of the scanning window W where the random winding has occurred (step S8), and determines whether or not the number of consecutive occurrences has exceeded a threshold value (step S9). If the number of consecutive occurrences has not exceeded the threshold value (step S9; No), the image processing device 20 proceeds to step S11.

[0052] In this way, steps S3 to S7 and S11 or steps S3 to S9 and S11 are repeated for one piece of imaging data ID, and if irregular winding occurs, the position of the scanning window W where it occurred and the number of times it continued are stored.

[0053] During this repetition, when scanning of the scanning window W is completed (step S11; Yes), the image processing device 20 determines whether or not winding is completed (step S12). Whether or not winding is completed is determined by a signal output from a device that winds the wire rope 3. If it is not determined that winding is completed (step S12; No), the image processing device 20 returns to step S1.

[0054] Thereafter, the following steps are performed: obtaining new imaging data ID (step S1), detecting a contour area CA (step S2), setting the position of the scanning window (step S3), extracting a partial area (step S4), generating a minimum bounding box MVB (step S5), and calculating its area (step S6). Then, the presence or absence of irregular winding is determined based on the area (step S7). If irregular winding is not determined to have occurred (step S7; No), a scan end determination is made (step S11). Steps S1 to S7 and S11 are repeated. If irregular winding is determined to have occurred during this repetition (step S7; Yes), the position of the scanning window W at the time of occurrence and the number of continuations are stored (step S8). If the number of continuations exceeds a threshold (step S9; Yes), the notification unit 16 notifies that irregular winding has occurred (step S10).

[0055] As described above, when scanning is completed (step S11; Yes), the image processing device 20 determines whether or not winding is completed (step S12). If it is determined that winding is completed (step S12; Yes), the image processing device 20 ends the process.

[0056] As shown in Figures 8A to 8F, when the wire rope 3 is normally wound around the drum 2 and no irregular winding occurs, even if the scanning window W is scanned, the area (a x b) of the minimum bounding box MVB shown by the solid line will be less than the reference bounding box 2 x k x k (area shown by the dotted line) shown by the dotted line. In this case, the determination unit 15 will not determine that irregular winding has occurred. In this case, any step that occurs in the outline of the wire rope 3 will be limited to the currently wound position. Since this step is approximately the diameter of the wire rope 3, the area of ​​the minimum bounding box MVB will not be larger than the reference bounding box 2 x k x k, which corresponds to two wire ropes 3.

[0057] On the other hand, as shown in Figure 9A, when the wire rope 3 wound around the drum 2 runs over, the area (a x b) of the minimum bounding box MVB shown by the solid line becomes larger than 2 x k x k (the area shown by the dotted line). When the wire rope 3 runs over multiple times, the area of ​​the minimum bounding box MVB becomes even larger than 2 x k x k (the area shown by the dotted line). In this case, the determination unit 15 determines that irregular winding has occurred.

[0058] 9B, when a gap occurs between the winding positions, the area (a×b) of the minimum bounding box MVB indicated by the solid line becomes larger than the area (2×k×k) indicated by the dotted line. In this case, the determination unit 15 determines that irregular winding has occurred.

[0059] In addition, if loosening occurs when wound around the drum 2, the outline of the wire rope 3 will become similar to the state shown in Figure 9A or Figure 9B, and the judgment unit 15 will determine that irregular winding has occurred in the wire rope 3.

[0060] In this embodiment, the notification unit 16 notifies the operator that a disorderly winding has occurred when it is determined multiple times that a disorderly winding has occurred at the same location. In other words, the determination unit 15 causes the notification unit 16 to notify the operator of the occurrence of a disorderly winding when the area (a × b) of the minimum bounding box MVB continues to be larger than the area (2 × k × k) of the reference bounding box RVB. This makes it possible to suppress erroneous detection of a disorderly winding caused by the wire rope 3 climbing up or a step caused by a gap occurring instantaneously. However, multiple consecutive occurrences (for a certain period of time) are not necessarily required as a notification condition. For example, the notification unit 16 may notify the operator of a disorderly winding if the disorderly winding occurs even once.

[0061] (Embodiment 2) Next, a description will be given of a second embodiment of the present invention. The irregular winding detection device 1 according to this embodiment has the same configuration as the irregular winding detection device 1 according to the first embodiment in that it includes an imaging device 10 and an image processing device 20.

[0062] As shown in FIG. 10, the irregular winding detector 1 according to this embodiment further includes a light source 5 as an illumination unit and a shade 6 as a shielding unit.

[0063] The light source 5 illuminates the outer surface of the wire rope 3 so as to increase the difference in brightness between the wire rope 3 in the contour area CA of the imaging data ID and other areas. The illumination light IL emitted from the light source 5 illuminates the outer surface of the wire rope 3 wound around the drum 2, that portion of the wire rope 3 that falls within the imaging field of view of the imaging device 10. This increases the brightness of the wire rope 3 imaged by the imaging device 10. For example, the brightness in the range of the rope area WA in the graph of FIG. 3 can be increased. This increases the difference in brightness with the background area BA, allowing the contour area CA of the wire rope 3 to be detected with high accuracy.

[0064] The shade 6 as a shielding part is disposed between the light source 5 and the imaging device 10, and blocks the illumination light IL from the light source 5. The shade 6 prevents the illumination light IL from directly entering and reducing the detection accuracy of the outline area CA of the wire rope 3.

[0065] In the above-described embodiments 1 and 2, the irregular winding detection device 1 has a contour detection unit 12 that detects the contour (contour area CA) of the wire rope 3 extending in the rotation axis direction (H-axis direction) of the drum 2 in an image (image data ID) of the wire rope 3 wound around the drum 2, and a judgment unit 15 that calculates the degree of change of the detected contour in the radial direction (V-axis direction) of the drum 2 (area a × b of the minimum bounding box MVB) and judges whether irregular winding of the wire rope 3 has occurred based on the magnitude of the calculated degree of change.

[0066] In addition, in the above-mentioned irregular winding detection device 1, the judgment unit 15 calculates the area of ​​the standardized shape that encompasses the outline of the wire rope 3 (area a × b of the minimum bounding box MVB) as the degree of change, and compares the calculated area with a reference area (area 2 × k × k of the reference bounding box RVB) to judge the occurrence of irregular winding.

[0067] Furthermore, in the above-described irregular winding detection device 1, the determination unit 15 causes the notification unit 16 to notify the occurrence of irregular winding when the state in which the calculated area is larger than the reference area continues.

[0068] Furthermore, in the above-mentioned irregular winding detection device 1, the judgment unit 15 calculates the degree of change for a contour (partial area PA) extracted from the detected contour and corresponding to the width of two wire ropes 3 in the axial direction of the drum 2.

[0069] As described above in detail, according to the first and second embodiments, occurrence of irregular winding of the wire rope 3 on the drum 2 is detected based on the size of the bounding box MVB, which is the smallest rectangle that encompasses the partial area PA of the outline area CA of the wire rope 3 extending in the direction of the rotation axis AX of the drum 2. This makes it possible to quickly and accurately detect occurrence of irregular winding.

[0070] Whether or not the wire rope 3 is irregularly wound is determined by whether the partial area PA, which is a part of the outline of the wire rope 3, is larger than the reference bounding box RVB, which encompasses two wire ropes 3. That is, irregular winding can be detected by simple image processing, in which the size of the shape formed by the partial area PA of the outline area CA of the wire rope 3 is used to detect irregular winding. For comparison with the minimum bounding box MVB, the reference bounding box RVB has a standardized shape similar to the minimum bounding box MVB, i.e., a rectangle in this embodiment. Its short side a has the number of pixels k, which corresponds to the diameter d of the wire rope 3, and its long side b has the number of pixels 2k, which corresponds to two wire ropes 3 arranged side by side. If the size of the reference bounding box RVB is smaller than the size of two wire ropes 3, it may not be possible to reliably capture steps that occur in the partial area PA due to phenomena such as the wire rope 3 climbing up or gaps. If the size of the reference bounding box RVB is set to two or more wire ropes 3, it is possible to reliably capture steps. However, in terms of being able to accurately grasp the position where the step occurs, it is optimal to set the size of the reference bounding box RVB to twice the size of the wire ropes 3.

[0071] Furthermore, this determination is made based on the size of the minimum bounding box MVB with the smallest area among rectangles that contain the partial area PA of the outline area CA of the wire rope 3 and that can be rotated within the image data ID. That is, irregular winding is detected using the minimum bounding box MVB that contains part of the partial area PA. When irregular winding occurs, the outline area CA of the wire rope 3 changes significantly in the V-axis direction, while even if irregular winding does not occur, the outline area CA of the wire rope 3 changes to some extent in the V-axis direction. In the above embodiment, by using the size of the minimum bounding box MVB with the smallest area among rectangles that contain the partial area PA as the determination requirement, it is possible to distinguish between large and small changes in the V-axis direction of the wire rope 3 when irregular winding occurs. This makes it possible to improve the robustness of irregular winding detection.

[0072] Furthermore, even when irregular winding occurs, the shape of the outline area CA of the wire rope 3 varies. In the above embodiment, the shape of the outline area CA is standardized by a minimum bounding box MVB, a rectangle containing the partial area PA of the outline area CA, whose angle θ is specified so as to minimize the area, and is used as a judgment criterion. The rotation angle θ of the minimum bounding box MVB represents the direction in which the outlines of the two wire ropes 3 extend, i.e., the overall orientation of the partial area PA. The size of the minimum bounding box MVB is determined by the extent to which the partial area PA changes in the direction perpendicular to the direction in which the outlines extend. Therefore, by using the minimum bounding box MVB containing the partial area PA, irregular winding can be detected using a uniform index regardless of the overall orientation of the partial area PA of the wire rope 3. As a result, the robustness of irregular winding detection can be improved.

[0073] In the above embodiment, the size of the reference bounding box RVB to be compared is set to a size that includes two wire ropes 3. However, the present invention is not limited to this. For example, if the change in the V-axis direction of the outline of the wire rope 3 is large even when no irregular winding occurs, the size of the reference bounding box RVB may be set to a size that has a margin relative to 2×k×k.

[0074] The number of pixels corresponding to the diameter d of the wire rope 3 may differ depending on the distance from the optical axis of the imaging device 10. For example, if the number of pixels corresponding to the diameter d of the wire rope 3 differs between both ends and the center of the drum 2, different values ​​of k may be used for determination depending on the number of pixels corresponding to each diameter d.

[0075] In the above embodiment, the scanning window W is shifted by one pixel at a time. However, the present invention is not limited to this. The scanning window W may be shifted by two or more pixels. For example, the length by which the scanning window W is shifted may be set to approximately half the diameter d of the wire rope 3.

[0076] In the above embodiment, as shown in FIG. 3, an area where the luminance is equal to or greater than a threshold value BL and equal to or less than a threshold value BH is detected as a contour area CA. However, the present invention is not limited to this. For example, the amount of change in luminance may be set as a threshold value in advance, and a pixel area having an amount of change in luminance equivalent to the set threshold may be detected as a contour area CA. The present invention is not limited to the method of detecting a contour area CA.

[0077] In the above embodiment, regardless of the winding position 4 of the wire rope 3 on the drum 2, the occurrence of irregular winding is determined for one piece of image data ID on the contour of the wire rope 3 wound from the -H end to the +H end of the drum 2. However, the present invention is not limited to this. The occurrence of irregular winding may be detected by focusing on the contour of the wire rope 3 near the winding position 4.

[0078] In the above embodiment, the wire rope 3 is wound from the -H end to the +H end of the drum 2. However, the wire rope 3 may be wound from the +H end to the -H end of the drum 2.

[0079] The hardware configuration and software configuration of the irregular winding detection device 1 are merely examples, and can be changed and modified as desired.

[0080] The core part of the processing of the irregular winding detection device 1, which is composed of the CPU 21, main memory unit 22, external memory unit 23, camera 24, display 25, audio output unit 26, etc., can be realized by using an ordinary computer system, not a dedicated system. For example, the irregular winding detection device 1 that executes the above processing may be configured by storing and distributing a computer program for executing the above operations in a computer-readable recording medium (flexible disk, CD-ROM, DVD-ROM, etc.), and installing the computer program on a computer. Also, the irregular winding detection device 1 may be configured by storing the computer program in a storage device of a server device on a communication network such as the Internet, and downloading the program to an ordinary computer system.

[0081] When the functions of the irregular winding detection device 1 are realized by sharing the functions of an OS (operating system) and an application program, or by cooperation between the OS and the application program, only the application program portion may be stored in a recording medium or storage device.

[0082] It is also possible to superimpose a computer program on a carrier wave and distribute it over a communications network. For example, the computer program may be posted on a bulletin board system (BBS) on the communications network and distributed over the network. The computer program may then be started and executed under the control of an operating system in the same way as any other application program, thereby enabling the above-mentioned processing to be performed.

[0083] This invention allows various embodiments and modifications without departing from the broad spirit and scope of this invention. Furthermore, the above-described embodiments are intended to explain this invention and do not limit the scope of this invention. That is, the scope of this invention is defined by the claims, not the embodiments. Various modifications made within the scope of the claims and the meaning of the invention equivalent thereto are considered to be within the scope of this invention.

[0084] The disclosures of the specification, drawings and abstract contained in Japanese Patent Application No. 2022-21546, filed on February 15, 2022, are incorporated herein by reference in their entirety. [Industrial Applicability]

[0085] The present invention can be applied to detecting the occurrence of turbulent winding of a wire rope on a drum of a winch. [Explanation of symbols]

[0086] 1. Irregular winding detection device 2 drums 2a flange 3. Wire rope 4 Winding position 5 light source 6 Shades 10. Imaging device 11. Imaging data acquisition unit 12 Contour detection section 13 Partial region extraction part 14 Bounding box generator 15 Judgment section 16. Information Department 20 Image processing device 21 CPU 22 Main memory 23 External memory unit 24 Camera 25 Display 26 Audio output section 28 Internal Bus 29 Programs AX Rotation Axis BA background area CA Contour Area ID image data MVB Minimum Bounding Box PA subarea RL reference line RVB Reference Bounding Box VB Bounding Box VL perpendicular W scanning window WA Rope Area

Claims

1. a contour detection unit that detects a contour of the wire rope extending in a rotation axis direction of the drum in a captured image of the wire rope wound around the drum; a determination unit that calculates the degree of change of the detected contour in the radial direction of the drum and determines whether or not irregular winding of the wire rope has occurred based on the magnitude of the calculated degree of change; and The determination unit calculates the area of ​​a standardized shape that includes the outline of the wire rope as the degree of change, and compares the calculated area with a reference area to determine whether the irregular winding has occurred. Irregular winding detection device.

2. The determination unit causes the notification unit to notify the occurrence of the irregular winding when the calculated area continues to be larger than the reference area. The irregular winding detection device according to claim 1.

3. The reference area is the area of ​​a standardized shape that encompasses the cross sections of two wire ropes, the determination unit calculates the degree of change for a contour corresponding to a width of two wire ropes in the rotation axis direction, the contour being extracted from the detected contour; The irregular winding detection device according to claim 1.

4. a contour detection unit that detects a contour of the wire rope extending in a rotation axis direction of the drum in a captured image of the wire rope wound around the drum; a determination unit that calculates the degree of change of the detected contour in the radial direction of the drum and determines whether or not irregular winding of the wire rope has occurred based on the magnitude of the calculated degree of change; and The contour detection unit detects, as the contour, a contour area extending in the direction of the rotation axis of the wire rope wound around the drum, an imaging unit that is disposed in a direction intersecting the rotation axis direction and captures an image of the wire rope to obtain the captured image; a partial region extraction unit that scans a scanning window having a certain length in the rotation axis direction with respect to the contour region detected by the contour detection unit, and extracts a partial region included in a section corresponding to the scanning window from the contour region; a bounding box generation unit that generates a minimum bounding box having a smallest area among bounding boxes that are rectangles that include the extracted partial region and can be rotated within a two-dimensional plane of the captured data of the captured image, each time the partial region extraction unit extracts a partial region; and and The determination unit determines whether or not irregular winding occurs in the wire rope based on the area of ​​the minimum bounding box generated by the bounding box generation unit. Irregular winding detection device.

5. When the number of pixels of the imaging data corresponding to the diameter of the wire rope is k, the length of the scanning window is 2k, The determination unit When the size of the minimum bounding box generated by the bounding box generation unit exceeds 2×k×k, it is determined that irregular winding has occurred in the wire rope. The irregular winding detector according to claim 4.

6. and a notification unit that notifies the occurrence of irregular winding in the wire rope when the state in which the determination unit determines that the size of the minimum bounding box exceeds 2 × k × k continues for a certain period of time. The irregular winding detection device according to claim 5.

7. A random winding detection device for detecting the occurrence of random winding of a wire rope wound around a drum, an imaging unit that is arranged in a direction intersecting the rotation axis direction of the drum and directly captures an image of the wire rope to obtain a captured image; an illumination unit that illuminates a portion of the outer surface of the wire rope that falls within the imaging field of view of the imaging unit so as to increase the brightness difference between the wire rope and a background area in the captured image; a contour detection unit that detects a contour of the wire rope extending in the rotation axis direction of the drum based on a change in brightness in the captured image; a determination unit that calculates the degree of change of the detected contour in the radial direction of the drum and determines whether or not irregular winding of the wire rope has occurred based on the magnitude of the calculated degree of change; A random winding detection device comprising:

8. a shielding unit disposed between the illumination unit and the imaging unit and configured to shield illumination light from the illumination unit; The irregular winding detector according to claim 7.

9. A method for detecting irregular winding executed by a random winding detection device, a contour detection step of detecting a contour of the wire rope extending in a rotation axis direction of the drum in a captured image of the wire rope wound around the drum; a determination step of calculating a degree of change in the detected contour in the radial direction of the drum, and determining whether or not irregular winding of the wire rope has occurred based on the magnitude of the calculated degree of change; Including, In the determination step, an area of ​​a standardized shape that encompasses the outline of the wire rope is calculated as the degree of change, and the calculated area is compared with a reference area to determine whether the irregular winding has occurred. Random winding detection method.

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