Position detection system, target, and position detection method

Abstract

To provide a position detection system, a target, and a position detection method capable of surely detecting the position of an object.SOLUTION: In a position detection system 100, a color information extraction unit 42 extracts color information from photographing information of a photographing unit 21 and specifies an extraction region. A position detection unit 43 can detect the relative positions of a suspended load SL and a crane 1 on the basis of the extraction result of the color information extraction unit 42. Thus, when using the extraction of the color information from the photographing information, the position detection unit 43 can detect the position of the suspended load SL in a state where the influence of disturbance such as reflection of sunlight is reduced. Therefore, the position of the suspended load SL can be surely detected.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a position detection system, a target, and a position detection method. [Background technology]

[0002] For example, Patent Document 1 describes a position detection system that uses an imaging unit installed on a crane to capture an image of a marker installed on a hanging part, and detects the position of an object suspended by the hanging part based on the captured image information. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 8-12259 Summary of the Invention [Problem to be solved by the invention]

[0004] In the position detection system described above, the markers provided on the hanging part have a belt-like or radial shape. Therefore, the position detection system detects the position of the object from only the information on the shape of the marker in the shooting information. Therefore, for example, if the reflected light of the sun from a puddle on the hanging part enters the shooting part, the shape of the marker cannot be distinguished, and the belt-like shape may be distorted, making it impossible to perform normal position detection. In addition, the reflected light from a protrusion such as a handrail may be mistaken for a marker. Therefore, there has been a demand for a position detection system that can reliably detect the position of an object.

[0005] The present invention has been made to solve the above problems, and has an object to provide a position detection system, a target, and a position detection method that can reliably detect the position of an object. [Means for solving the problem]

[0006] The position detection system of the present invention is a position detection system that detects the position of an object suspended by the hanging member and hanging part of a crane, and is provided on a crane structure that moves together with the hanging point of the hanging member, and comprises an imaging unit that photographs the object, a color information extraction unit that extracts color information from the imaging information of the imaging unit and identifies the extraction area, and a position detection unit that detects the relative position of the object and the crane based on the extraction result of the color information extraction unit.

[0007] In the position detection system according to the present invention, the color information extraction unit extracts color information from the photographing information of the photographing unit and identifies an extraction area. The position detection unit can detect the relative position between the object and the crane based on the extraction result of the color information extraction unit. In this way, when the position detection unit is based on the extraction of color information from the photographing information, it is possible to detect the position of the object while reducing the influence of disturbances such as reflected sunlight. As a result, the position of the object can be detected reliably.

[0008] The position detection unit may detect a plurality of targets having different characteristics. In this case, the position detection unit can detect the position of the object in more detail by effectively utilizing the individual characteristics of each target.

[0009] The position detection unit may detect a plurality of targets having different color information as different characteristics. In this case, a plurality of targets having different characteristics can be easily prepared by simply changing the color information of each target.

[0010] The position detection unit may detect the orientation of the object in the rotation direction in the horizontal plane based on the positional relationship of multiple targets having different color information from each other. In other words, since the characteristics of the multiple targets are different from each other, the position detection unit can easily detect the orientation of the object in the rotation direction by referring to the positional relationship of each target in the rotation direction.

[0011] The position detection unit may detect the location of the object in addition to the object based on the imaging information from a single imaging unit. In this case, the position detection unit can easily grasp the relative positional relationship between the object and the location based on the imaging information from the single imaging unit without using multiple imaging units.

[0012] The position detection system may include an attitude adjustment mechanism that adjusts the attitude of the imaging unit so that the imaging unit faces downward regardless of the movement of the structure. In this case, even in the case of a crane whose attitude of the imaging unit is likely to change depending on the movement of the structure, such as a jib crane, the attitude adjustment mechanism can adjust the attitude of the imaging unit so that it faces downward.

[0013] The target according to the present invention is a target for detecting the position of a hanging member of a crane and an object suspended by the hanging portion, and has any color information that can be extracted within an image.

[0014] By providing this target on the object, the position detection system can extract color information of the target in the image and perform position detection. In this case, it is possible to obtain the same effects as those of the position detection system described above.

[0015] The position detection method of the present invention is a position detection method for detecting the position of an object suspended by the hanging member and hanging part of a crane, and includes an imaging process for photographing the object using an imaging unit provided on the crane structure that moves together with the hanging point of the hanging member, a color information extraction process for extracting color information from the imaging information obtained in the imaging process and identifying an extraction area, and a position detection process for detecting the relative position of the object and the crane based on the extraction result obtained in the color information extraction process.

[0016] According to this position detection method, it is possible to obtain the same functions and effects as those of the above-mentioned position detection system. Effect of the Invention

[0017] According to the present invention, it is possible to provide a position detection system, a target, and a position detection method that can reliably detect the position of an object. [Brief description of the drawings]

[0018] [Figure 1] 1 is a schematic diagram showing a position detection system according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic configuration diagram of a crane to which FIG. 1 is applied. [Diagram 3] 4 is an example of an image captured by a capturing unit. [Figure 4] FIG. 2 is a perspective view showing a configuration of a posture adjustment mechanism. [Diagram 5] 11 is a diagram for explaining the processing content of a color information extraction unit; FIG. [Figure 6] 4 is a diagram for explaining the processing content of a position detection unit; FIG. [Figure 7] 4 is an example of an image captured by a capturing unit. [Figure 8] 4 is a flowchart showing the contents of a control process of the position detection system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, preferred embodiments of the position detection system according to the present invention will be described with reference to the drawings. Fig. 1 is a schematic diagram showing the position detection system according to this embodiment. Fig. 2 is a schematic diagram of a crane to which Fig. 1 is applied.

[0020] The position detection system 100 according to this embodiment is a system that detects the position of a load SL (object) suspended by the suspending member 17 and the suspending part 16 of the crane 1. The position detection system 100 includes, as a system configuration, a measuring device 10, a control device 40, an input unit 51, an output unit 52, and targets 50A and 50B.

[0021] 2, the crane 1 exemplified in this embodiment is a jib crane that can rotate and travel. The crane 1 has a traveling body 11, a tower body 12, a rotating body 13, a jib 14, and a mast 15 as an apparatus configuration.

[0022] The running body 11 drives the crane 1 along the running rail by driving the wheels on the running rail. The tower body 12 is a columnar structure erected on the running body 11. The rotating body 13 is provided at the upper end of the tower body 12 and can rotate around a vertical axis CL with respect to the tower body 12. The rotating body 13 includes a driver's cab 13a at its upper part. The jib 14 is pin-connected to a part of the rotating body 13. The mast 15 is erected on the rotating body 13. The rear end of the rotating body 13, the mast top which is the upper end of the mast 15, and the tip of the jib 14 are supported by each other by a wire rope W1. By winding and unwinding the wire rope W1, the jib 14 performs a hoisting operation with its base end as a fulcrum. In addition, the wire rope W2 is connected to the suspending part 16. By winding and unwinding the wire rope W2, the suspending part 16 moves in the up and down direction. In addition, the part of the wire rope W2 that extends downward from the upper end of the jib 14 to suspend the suspension part 16 and the load SL is referred to as the suspension member 17. In addition, the point that is the base point of the amplitude of the suspension member 17 is referred to as the "suspension point SP."

[0023] Targets 50A and 50B are provided on the hanging part 16. As shown in FIG. 3, the targets 50A and 50B are provided on the upper surface 16a of the hanging part 16 so that the imaging unit 21 described below can image them from above. The targets 50A and 50B are arranged side by side at a position closer to one side than the center of the hanging part 16. The targets 50A and 50B have a circular shape. However, the position, shape, and size of the targets 50A and 50B are not particularly limited. The number of targets is also not particularly limited.

[0024] The targets 50A and 50B have different characteristics. The different characteristics may be characteristics that can distinguish the targets 50A and 50B in an image, such as different color information and different shapes. In this embodiment, the targets 50A and 50B have different color information. The targets 50A and 50B each have any color information that can be extracted from the image. The any color information that can be extracted from the image may be color information that can be extracted by processing of the color information extraction unit 42 described later. Such color information may be, specifically, various colors such as red, green, and blue, and may be any color other than white. For example, the target 50A is entirely red, and the target 50B is entirely green. However, the colors of the targets 50A and 50B are not particularly limited.

[0025] 1, the measurement device 10 includes an imaging unit 21, a distance measurement unit 22, and an inclination detection unit 23. The measurement device 10 transmits detection information detected by the imaging unit 21, the distance measurement unit 22, and the inclination detection unit 23 to the control device 40. In addition, the measurement device 10 receives a command signal from the control device 40.

[0026] The photographing unit 21 is a measuring device that photographs the load SL. The photographing unit 21 is provided on the structure 30 of the crane 1 that moves together with the hanging point SP. In this embodiment, as shown in FIG. 2, the photographing unit 21 is attached to a mounting member 31 provided at the tip of the jib 14. The photographing unit 21 is arranged so that the lens portion faces downward in the vertical direction. The photographing unit 21 can acquire photographing information within the photographing range E that spreads downward. The photographing range E is set to a size such that the load SL does not go outside the photographing range E even if the swing angle of the load SL becomes the maximum allowable value. It is preferable that the photographing unit 21 can cover the entire range of the movement range of the load SL with only one photographing range E. An example of the photographing information acquired by the photographing unit 21, i.e., an image, is shown in FIG. 3. The photographing unit 21 may be configured by a general color camera. Therefore, the image captured by the photographing unit 21 is a color image.

[0027] The photographing unit 21 is provided near the suspension point SP. However, the photographing unit 21 is a structure 30 that moves together with the suspension point SP, and may be provided anywhere as long as it is in a position where the suspended load SL can be photographed. For example, the photographing unit 21 may be provided near the center of the jib 14 in the longitudinal direction, or near the connection part of the jib 14 with the rotating body 13.

[0028] Here, as shown in FIG. 4, the position detection system 100 includes a posture adjustment mechanism 60 that adjusts the posture of the photographing unit 21 so that the photographing unit 21 faces downward regardless of the movement of the structure 30. The posture adjustment mechanism 60 includes a holding unit 61, a hinge unit 62, and a fixed unit 63. The holding unit 61 is a member that holds the photographing unit 21. The holding unit 61 includes a bottom plate unit 61a, an upper plate unit 61b, and a column unit 61c that connects the bottom plate unit 61a and the upper plate unit 61b at four corners. The photographing unit 21 is provided on the lower surface of the bottom plate unit 61a. In addition, the tilt detection unit 23 is provided on the upper surface of the bottom plate unit 61a. The bottom plate unit 61a is configured to be thicker and heavier than the upper plate unit 61b. The hinge unit 62 is a member that rotatably connects the upper plate unit 61b of the holding unit 61 and the fixed unit 63.

[0029] The fixed part 63 is a member for fixing the attitude adjustment mechanism 60 to the structure 30 of the crane 1. As the attitude of the structure 30 of the crane 1 changes, the attitude of the fixed part 63 also changes. For example, in the state shown in FIG. 4(a), the fixed part 63 is attached to the structure 30 in a horizontal state. In this state, the bottom plate part 61a of the holding part 61 is also in a horizontal state. In contrast, when the jib 14 is raised and lowered, as shown in FIG. 4(b), the fixed part 63 assumes an attitude inclined with respect to the horizontal. At this time, the holding part 61 rotates relative to the fixed part 63 by the hinge part 62. Therefore, the horizontal state of the bottom plate part 61a of the holding part 61 is maintained. At this time, the weight of the bottom plate part 61a is large, so that it is easy to rotate with respect to the fixed part 63. As a result, regardless of the movement of the structure 30, the photographing part 21 is maintained in a state facing downward.

[0030] As shown in FIG. 1, the distance measurement unit 22 is a measuring device that detects the distance between the photographing unit 21 and the suspended load SL. The distance can be approximated to the length of the suspension member 17. Therefore, the distance measurement unit 22 may be configured by a detection sensor for detecting the unwinding amount provided on a winding device 32 that winds up the wire rope W2 (see FIG. 2). The detection sensor can detect the length of the suspension member 17 based on the unwinding amount of the unwound wire rope W2. Note that the distance measurement unit 22 is not limited to such a detection sensor provided on the winding device 32, and may be configured by, for example, a laser-type or radar-type distance measuring device provided near the photographing unit 21. Also, the distance measurement unit 22 may be omitted.

[0031] The tilt detection unit 23 is a measuring device that detects the amount of tilt of the photographing unit 21. When the amount of tilt of the photographing unit 21 with respect to the horizontal direction changes, the tilt detection unit 23 detects the amount of tilt. When the amount of tilt of the photographing unit 21 changes, the tilt detection unit 23 is provided at a position where the photographing unit 21 will tilt by the same amount of tilt. The tilt detection unit 23 may be attached to the same member as the member to which the photographing unit 21 is attached. For example, the tilt detection unit 23 may be provided on the bottom plate portion 61a to which the photographing unit 21 is attached (see FIG. 4). The tilt detection unit 23 may be omitted.

[0032] The input unit 51 is an interface through which the user inputs information to the control device 40. For example, a keyboard, a mouse, a touch panel, a microphone, etc. are used as the input unit 51. The output unit 52 is an interface that outputs information from the control device 40 to the user. For example, a monitor, a speaker, etc. are used as the output unit 52.

[0033] The control device 40 is a device that controls the entire position detection system 100. The control device 40 includes a processor, a memory, a storage, a communication interface, and a user interface, and is configured as a general computer. The processor is a computing device such as a CPU (Central Processing Unit). The memory is a storage medium such as a ROM (Read Only Memory) or a RAM (Random Access Memory). The storage is a storage medium such as a HDD (Hard Disk Drive). The communication interface is a communication device that realizes data communication. The processor controls the memory, storage, communication interface, and user interface, and realizes functions to be described later. In the control device 40, for example, a program stored in the ROM is loaded into the RAM, and the program loaded into the RAM is executed by the CPU, thereby realizing various functions. The control device 40 may be composed of multiple computers.

[0034] The control device 40 includes an information acquisition unit 41, a color information extraction unit 42, a position detection unit 43, and a storage unit 44.

[0035] The information acquiring unit 41 acquires detection information from the measurement device 10. The information acquiring unit 41 acquires shooting information (i.e., images) captured by the imaging unit 21. The information acquiring unit 41 also acquires measurement results by the distance measuring unit 22 and / or detection results by the tilt detection unit 23.

[0036] The storage unit 44 stores various information used for position detection by the position detection system 100. The storage unit 44 stores information regarding the targets 50A, 50B provided on the hanging part 16. Examples of such information include color information, shape information, size information, and position information of the targets 50A, 50B.

[0037] The color information extraction unit 42 extracts color information from the photographing information of the photographing unit 21 and specifies an extraction region. The color information extraction unit 42 extracts specific color information from an image and specifies a region having the color information as an extraction region. The color information extraction unit 42 specifies at least a region corresponding to the targets 50A, 50B as an extraction region. The color information extraction unit 42 specifies a region in the image other than the targets 50A, 50B as an extraction region as long as the region has specific color information.

[0038] The position detection unit 43 detects the relative position between the load SL and the crane 1 based on the extraction result of the color information extraction unit 42. The position detection unit 43 can detect the sway angle of the load SL as the relative position between the load SL and the crane 1. For example, as shown in FIG. 3, the position detection unit 43 sets the position vertically below the suspension point SP as the origin OP (swing angle 0 point) of the sway angle in the image of the photographing unit 21. The position detection unit 43 detects the distance between the color pattern of the targets 50A, 50B in the image and the origin OP as the sway angle. Here, the position detection unit 43 detects the distance in the X direction between the center of gravity WP of the color pattern and the origin OP as the X-direction sway angle θx. The position detection unit 43 detects the distance in the Y direction between the center of gravity WP of the color pattern and the origin OP as the Y-direction sway angle θy. In this way, the position detection unit 43 detects the relative position of the load SL with respect to the crane 1 based on the sway angle of the color pattern center of gravity WP.

[0039] The position detection unit 43 detects the multiple targets 50A, 50B having different characteristics from each other. The position detection unit 43 detects the multiple targets 50A, 50B having different color information from each other as the different characteristics from each other.

[0040] Next, an example of specific processing of the color information extraction unit 42 and the position detection unit 43 will be described with reference to Fig. 5 and Fig. 6. Fig. 5(a) shows a color image CP captured by the imaging unit 21. This color image CP is an image composed of RGB (red, green, blue) image signals. The hanging part 16 and targets 50A and 50B are captured in the color image CP. In the color image CP, the target 50A is displayed in red, the target 50B is displayed in green, and the hanging part 16 is displayed in white due to the influence of light. In addition, the color image CP also captures the state farther away than the hanging part 16. Of these, the objects OB1 and OB2 are displayed in red, and the objects OB3, OB4, and OB5 are displayed in green.

[0041] In order to extract color information, the color information extraction unit 42 converts the RGB (red, green, blue) image signals of the color image CP into HSV (hue, saturation, brightness). Then, the color information extraction unit 42 obtains filtered images FP1 and FP2 obtained by filtering the H (hue) image with the colors of the targets 50A and 50B. FIG. 5(b) shows a filtered image FP1 filtered with the red color of the target 50A. FIG. 5(c) shows a filtered image FP2 filtered with the green color of the target 50B. As shown in FIG. 5(b), in the filtered image FP1, an area having red color information is displayed brightly, and the rest is displayed darkly. Also, as shown in FIG. 5(b), in the filtered image FP2, an area having green color information is displayed brightly, and the rest is displayed darkly.

[0042] Therefore, the color information extraction unit 42 extracts red color information from the filter image FP1, and extracts regions having the red color information as extraction regions RE1, RE2, and RE6. The extraction region RE1 corresponds to the object OB1, the extraction region RE2 corresponds to the object OB2, and the extraction region RE6 corresponds to the target 50A. The color information extraction unit 42 extracts green color information from the filter image FP2, and extracts regions having the green color information as extraction regions RE3, RE4, RE5, and RE7. The extraction region RE3 corresponds to the object OB3, the extraction region RE4 corresponds to the object OB4, the extraction region RE5 corresponds to the object OB5, and the extraction region RE7 corresponds to the target 50B.

[0043] Next, the position detection unit 43 identifies the extraction regions RE1 to RE7 that correspond to the targets 50A and 50B. Note that FIG. 6 shows a composite filter image FP3 obtained by combining the filter image FP1 and the filter image FP2. As shown in FIG. 6, the position detection unit 43 evaluates the extraction regions RE1 to RE7 and calculates the center of gravity and area of ​​each region. In FIG. 6, "Pr" indicates a red extraction region, "Pg" indicates a green extraction region, the numbers attached to "Pr" and "Pg" are identification numbers, the numbers in parentheses indicate the areas of the extraction regions, and the cross marks indicate the centers of gravity of the extraction regions.

[0044] The relationship between the distance between the imaging unit 21 and the targets 50A, 50B, the area of ​​the targets 50A, 50B in the image, and the inter-element distance between the targets 50A, 50B is calculated or measured in advance and stored in the storage unit 44 as associated comparison data. The position detection unit 43 obtains the area of ​​the targets 50A, 50B in the composite filter image FP3 and the expected value of the inter-element distance between the targets 50A, 50B by comparing the distance measured by the distance measurement unit 22 with the comparison data in the storage unit 44. In addition, the expected value of the aspect ratio of the circumscribing rectangle of the targets 50A, 50B in the composite filter image FP3 (the rectangle indicated by the white dashed line in FIG. 6) is stored in advance in the storage unit 44.

[0045] The position detection unit 43 specifies the extraction regions corresponding to the targets 50A and 50B by removing from the candidates, among the extraction regions RE1 to RE7 in the composite filter image FP3, those that do not correspond to the targets 50A and 50B. Specifically, the position detection unit 43 removes from the candidates the extraction regions whose area values ​​and the aspect ratio values ​​of the circumscribing rectangles deviate from the expected values ​​of the targets 50A and 50B by a certain amount or more. The position detection unit 43 removes the extraction regions RE2, RE3, and RE4 from the candidates because their areas are too small compared to the expected values ​​of the targets 50A and 50B. The position detection unit 43 removes the extraction region RE1 from the candidates because the aspect ratio of the circumscribing rectangle of the extraction region RE1 deviates significantly from the expected values ​​of the targets 50A and 50B. As a result, the extraction regions RE5, RE6, and RE7 remain as candidates. The position detection unit 43 calculates the inter-element distance D1 between the extraction regions RE6 and RE7, and the inter-element distance D2 between the extraction regions RE5 and RE6. The position detection unit 43 compares the inter-element distances D1 and D2 with the expected values ​​of the inter-element distances of the targets 50A and 50B. As a result, the position detection unit 43 recognizes that the extraction regions RE6 and RE7 associated with the inter-element distance D1 closest to the expected value are the targets 50A and 50B.

[0046] The position detection unit 43 recognizes that the extraction area RE6 corresponds to the target 50A because it is a red area, and recognizes that the extraction area RE7 corresponds to the target 50B because it is a green area. Here, the position detection unit 43 can detect the posture of the load SL in the rotation direction in the horizontal plane based on the positional relationship of the multiple targets 50A, 50B having different color information from each other. Note that the rotation direction here is a rotation direction based on a central axis extending in the vertical direction. For example, the posture in which the extraction area RE6 corresponds to the target 50A and the extraction area RE7 corresponds to the target 50B is assumed to be the normal posture of the load SL (0° posture in the rotation direction). In contrast, when the position detection unit 43 detects that the extraction area RE6 corresponds to the target 50B and the extraction area RE7 corresponds to the target 50A, it detects that the posture of the load SL in the rotation direction in the horizontal plane has rotated 180°.

[0047] The position detection unit 43 sets the center of gravity of the extraction regions RE6 and RE7 as the target positions of the targets 50A and 50B. The position detection unit 43 also calculates the center of gravity WP of the color pattern from the target positions of both. The position detection unit 43 calculates the skew angle from the geometric arrangement characteristics between the targets 50A and 50B, which are known in advance.

[0048] Here, when the attitude (lens orientation) of the photographing unit 21 is constant with respect to the vertical direction, the position detection unit 43 detects the swing angles θx, θy (see FIG. 3) based on the distance between the position of the origin OP1 of the swing angle obtained in advance by measurement or the like and the center of gravity WP of the color pattern obtained above. The position of the origin OP1 obtained in advance is stored in the storage unit 44. Here, when the attitude of the photographing unit 21 changes, the position of the origin of the swing angle changes. In FIG. 6, it has changed from the origin OP1 to the origin OP2. Therefore, the position detection unit 43 corrects the origin OP2 of the swing angle to the original position, that is, the origin OP1, based on the detection result of the tilt detection unit 23.

[0049] The control device 40 may constantly take in the photographing information of the photographing unit 21, the detection result of the tilt detection unit 23, and the measurement result of the distance measurement unit 22, and may constantly perform evaluation calculation of the sway angle. Then, the control device 40 may transmit the information on the sway angle to a higher-level operation screen (output unit 52), a sway prevention system, or the like.

[0050] Here, as shown in FIG. 7, the position detection unit 43 detects the load SL and the installation location 71 of the load SL based on the photographing information from the single photographing unit 21. The installation location 71 is a location where the load SL suspended by the crane 1 is installed, or a location where the load SL to be suspended by the crane 1 is installed. In the example shown in FIG. 7, the installation location 71 is illustrated as a location where the load SL suspended by the crane 1 is installed. Targets 70A and 70B are provided in the installation location 71. The targets 70A and 70B are different from each other and have color information different from the targets 50A and 50B. In the installation location 71, a load installation frame 72 is set that strictly defines the area where the load SL is installed. The targets 70A and 70B are provided outside the load installation frame 72. The position detection unit 43 identifies the positions of the targets 70A and 70B in a manner similar to that of the targets 50A and 50B. Since the positional relationship between the targets 70A, 70B and the hanging load installation frame 72 is set in advance, the position detection unit 43 can detect the position of the hanging load installation frame 72 in the image based on the targets 70A, 70B.

[0051] As described above, the color patterns of the targets 50A, 50B and the color patterns of the targets 70A, 70B enable the position detection unit 43 to distinguish between the suspending part 16 and the installation location 71, and to evaluate the position and angle on the same image. Furthermore, when the crane 1 automatically holds or lowers the load SL, it can detect the relative position between the suspending part 16 and the installation location 71 based on the detection contents of the suspending part 16 and the installation location 71. This enables the crane 1 to handle the load SL while checking that it is within the relative position and angle range in which the load SL can be held and lowered.

[0052] Next, the content of the position detection method by the position detection system 100 will be described with reference to Fig. 8. As shown in Fig. 8, the photographing unit 21 photographs the suspended load SL (step S110: photographing step). The photographing unit 21 transmits the photographing information to the control device 40, and the information acquiring unit 41 of the control device 40 acquires the photographing information.

[0053] Next, the color information extraction unit 42 extracts color information from the photographing information in step S110 and specifies an extraction area (step S120: color information extraction step). Next, the position detection unit 43 detects the relative position between the load SL and the crane 1 based on the extraction result in step S120 (step S130: position detection step).

[0054] Specifically, in step S130, the position detection unit 43 identifies the extraction regions corresponding to the targets 50A, 50B from among the multiple extraction regions (step S140). Next, the position detection unit 43 detects the sway angle based on the center of gravity of the targets 50A, 50B (step S150). Next, the position detection unit 43 detects the position of the load SL based on the sway angle detected in step S150 (step S160). When step S160 ends, the control process shown in FIG. 8 ends, and the process starts again from step S110.

[0055] Next, the functions and effects of the position detection system 100, the targets 50A and 50B, and the position detection method according to this embodiment will be described.

[0056] In the position detection system 100 according to this embodiment, the color information extraction unit 42 extracts color information from the photographing information of the photographing unit 21 to identify the extraction area. Furthermore, the position detection unit 43 can detect the relative position between the load SL and the crane 1 based on the extraction result of the color information extraction unit 42. In this way, when the position detection unit 43 is based on the extraction of color information from the photographing information, it is possible to detect the position of the load SL in a state where the influence of disturbances such as reflected sunlight is reduced. As described above, the position detection unit 43 can reliably detect the position of the load SL without erroneously detecting light sources other than the target.

[0057] The position detection unit 43 may detect a plurality of targets 50A, 50B having different characteristics from each other. In this case, the position detection unit 43 can detect the position of the load SL in more detail by effectively utilizing the individual characteristics of each of the targets 50A, 50B.

[0058] The position detection unit 43 may detect multiple targets 50A, 50B having different color information as different characteristics. In this case, multiple targets 50A, 50B with different characteristics can be easily prepared by simply changing the color information of each target 50A, 50B. For example, when different characteristics are obtained by changing the shape, it is necessary to devise the shape of each target and to consider restrictions on the installation location of the hanging part 16. In contrast, the targets 50A, 50B are both simple circular shapes, and the characteristics can be easily changed by simply changing the color of each target.

[0059] The position detection unit 43 may detect the posture of the load SL in the rotation direction in the horizontal plane based on the positional relationship of the multiple targets 50A, 50B having different color information from each other. That is, since the multiple targets 50A, 50B have different characteristics from each other, the position detection unit 43 can easily detect the posture of the load SL in the rotation direction by referring to the positional relationship of each target 50A, 50B in the rotation direction.

[0060] The position detection unit 43 may detect the installation location of the load SL in addition to the load SL based on the photographing information from a single photographing unit 21. In this case, the position detection unit 43 can easily grasp the relative positional relationship between the load SL and the installation location based on the photographing information from the single photographing unit 21 without using multiple photographing units 21.

[0061] The position detection system 100 may include an attitude adjustment mechanism 60 that adjusts the attitude of the imaging unit 21 so that the imaging unit 21 faces downward regardless of the movement of the structure 30. In this case, even in the case of a crane in which the attitude of the imaging unit 21 is likely to change depending on the movement of the structure 30, such as a jib crane, the attitude adjustment mechanism 60 can adjust the attitude of the imaging unit 21 so that the imaging unit 21 faces downward.

[0062] The targets 50A, 50B according to this embodiment are for detecting the position of a load SL suspended by the suspending member 17 and the suspending portion 16 of the crane 1, and have any color information that can be extracted from an image.

[0063] By attaching the targets 50A, 50B to the suspended load SL, the position detection system 100 can extract color information of the targets 50A, 50B from the image and perform position detection. In this case, the same effects as those of the position detection system 100 described above can be obtained.

[0064] The position detection method of this embodiment is a position detection method for detecting the position of a load SL suspended by the suspension member 17 and suspension part 16 of the crane 1, and includes an imaging process for imaging the load SL using an imaging unit 21 provided on the structure 30 of the crane 1 which moves together with the suspension point SP of the suspension member 17, a color information extraction process for extracting color information from the imaging information obtained in the imaging process and identifying the extraction area, and a position detection process for detecting the relative position of the load SL and the crane 1 based on the extraction result obtained in the color information extraction process.

[0065] According to this position detection method, it is possible to obtain the same functions and effects as those of the position detection system 100 described above.

[0066] Furthermore, by using color information, the position detection system 100 can perform position detection that is highly robust against disturbances such as sunlight reflection. Furthermore, because position detection is performed using color information, a general color camera can be used as the photographing unit 21. This results in an inexpensive system, and the system can be used in combination with a camera for surveillance purposes, making the system easy to install. Furthermore, since it is no longer necessary to place a special target such as a light source on the hanging part 16, the system can be easily installed.

[0067] The present invention is not limited to the above-described embodiments.

[0068] For example, in the above embodiment, a jib crane is exemplified as the crane 1, but the type of the crane is not particularly limited. For example, the present invention may be applied to cranes such as overhead cranes, goliath cranes, and ladle cranes. In the case of a ladle crane, work is performed in an environment where molten red-hot metal is present. Therefore, the position detection system 100 may extract the color of the red-hot metal in the background of the suspended load SL to detect the position of the suspended load SL. In this way, even in cases where a target cannot be placed on the suspended load, such as a ladle crane, or where the color pattern of the hoisting tool is buried in dust or the like, the position detection system can detect the color of the molten steel as a detection target, making it possible to detect the swing of the suspended load.

[0069] In the above embodiment, the distance between the photographing unit 21 and the load SL is measured using the distance measuring unit 22. When the distance measuring unit 22 is omitted, the load SL may be recognized based only on the information of the targets 50A, 50B in the image, and the distance between the photographing unit 21 and the load SL may be estimated based on the size of the targets 50A, 50B on the image.

[0070] To improve the robustness of shake detection, a colored shape pattern may be created by the light source on the hanging part 16, and the position may be detected using the brightness information as well. This makes it possible to remove disturbances and improve robustness. Color information may also be extracted by using a colored light source such as a police light as a target.

[0071] The position detection unit 43 may be capable of simultaneously detecting the color patterns of a plurality of different loads SL. In this case, by giving each load SL a unique color pattern, the position detection unit 43 can identify the load SL as well as the sway angle.

[0072] In the above-described embodiment, the position detection system 100 detects the position of the suspended load SL by using a single photographing unit 21, but a plurality of photographing units 21 may be used. [Explanation of symbols]

[0073] 10...crane, 21...imaging unit, 42...color information extraction unit, 43...position detection unit, 50A, 50B, 70A, 70B...target, 60...attitude adjustment mechanism, 100...position detection system.

Claims

1. A position detection system for detecting a position of an object suspended by a hoisting member and a hoisting part of a crane, An imaging unit that is provided on a structure of the crane that moves together with the hanging point of the hanging member and images the object; a color information extraction unit that extracts color information from the photographing information of the photographing unit and specifies an extraction area; a position detection unit that detects a relative position between the object and the crane based on an extraction result of the color information extraction unit, A position detection system in which the position detection unit detects a plurality of targets having different color information as different characteristics.

2. The position detection system according to claim 1 , wherein the position detection unit detects an attitude of the object in a rotational direction within a horizontal plane based on a positional relationship between a plurality of the targets having mutually different characteristics.

3. The position detection system according to claim 1 , wherein the position detection unit detects, in addition to the object, a location where the object is installed, based on the imaging information from a single imaging unit.

4. The position detection system according to any one of claims 1 to 3, further comprising an attitude adjustment mechanism that adjusts the attitude of the imaging unit so that the imaging unit faces downward regardless of the movement of the structure.

5. A target for detecting the position of an object suspended by a hoisting member and a hoisting part of a crane, Any color information that can be extracted from the image, A target including a plurality of targets having different color information as different characteristics from each other.

6. A position detection method for detecting a position of an object suspended by a suspending member and a suspending part of a crane, comprising: An imaging step of imaging the object by an imaging unit provided on a structure of the crane that moves together with the suspension point of the suspension member; a color information extraction step of extracting color information from the photographing information in the photographing step and specifying an extraction area; and a position detection step of detecting a relative position between the object and the crane based on a result of extraction in the color information extraction step. In the position detection step, a plurality of targets having different color information as different characteristics are detected.

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