Measurement device, measurement method, and program

Abstract

A measurement device 10 comprises a control unit 11 that detects, from an image in which a moving means including a tire is imaged, at least one marker provided to a surface of a groove of the moving means, and calculates, on the basis of the detected marker, a residual groove amount of the moving means.

Description

Measurement device, measurement method, and program

[0001] The present disclosure relates to a measurement device, a measurement method, and a program.

[0002] Conventionally, in order to accurately and reliably determine the degree of tire wear, a method has been known in which a recess is formed in the groove wall surface of a groove formed on the tire surface and a luminous material is attached to the recess (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2014-133486

[0004] Conventional technology requires a human to visually recognize the degree of wear or to measure it with a dedicated measuring device, which requires a lot of man-hours. Furthermore, when tires are large, it is sometimes impossible to visually check. Furthermore, it can only determine the level of remaining tread depth (RTD) in localized areas, and cannot provide accurate figures for a wide area. Furthermore, visual judgment or measurement with a dedicated measuring device requires stopping the vehicle. As such, there is room for improvement in the technology for measuring the remaining tread depth of tires.

[0005] In view of the above circumstances, an object of the present disclosure is to improve the technology for measuring the remaining tread depth of a vehicle including a tire.

[0006] The gist of the present disclosure for solving the above problems is as follows.

[0007] (1) A measuring device comprising a control unit that detects at least one mark provided on the surface of a groove of a tire of a vehicle from an image of the vehicle including a tire, and calculates the remaining groove depth of the vehicle based on the detected mark.

[0008] (2) The measuring device according to (1) above, wherein the mark is a mark related to the depth of the groove.

[0009] (3) The measuring device according to (1) or (2) above, wherein the control unit generates, based on the image, at least one cross-sectional profile showing the outline of a cross section of the moving means at the position where the marker is detected.

[0010] (4) The measuring device according to (3) above, wherein the cross-sectional profile has a plane perpendicular to a straight line along the width direction of the tire.

[0011] (5) The measuring device according to (3) or (4) above, wherein the control unit generates a plurality of cross-sectional profiles at different positions in the width direction as the at least one cross-sectional profile.

[0012] (6) The measuring device according to (5) above, wherein the control unit determines at least one of the number and spacing of the plurality of cross-sectional profiles to be generated based on characteristic information indicating characteristics of the moving means.

[0013] (7) A measuring method executed by a computer, comprising: detecting a mark provided on the surface of a groove of a moving means from an image of the moving means; and calculating the remaining groove depth of the moving means based on the detected mark.

[0014] (8) A program for causing a computer to function as the measurement device according to any one of (1) to (6) above.

[0015] According to one embodiment of the present disclosure, it is possible to improve the technology for measuring the remaining tread depth of a vehicle including tires.

[0016] It is a schematic diagram showing the configuration of a measurement system. It is a flowchart showing the operation executed by the measurement device. It is a diagram showing an example of an image input to the measurement device. It is a diagram for explaining the detection of a marker. It is a diagram for explaining the generation of a cross-sectional profile. It is a diagram showing an example of a cross-sectional profile.

[0017] Hereinafter, one embodiment will be described in detail with reference to the drawings.

[0018] 1 shows an example of the configuration of a measurement system 1 according to one embodiment. The measurement system 1 includes a measurement device 10 and a camera 20. The measurement device 10 and the camera 20 are connected via a network 30 wirelessly, by wire, or by a combination of wireless and wired connections. The measurement device 10 and the camera 20 may be integrated into one unit.

[0019] The camera 20 may be a 3D camera such as a stereo camera or a ToF (Time of Flight) camera. The camera 20 is capable of transmitting an image of a tire serving as a means of transportation to the measuring device 10 via the network 30.

[0020] The network 30 may include the Internet, at least one Wide Area Network (WAN), at least one Metropolitan Area Network (MAN), or a combination thereof. The network 30 may also include at least one wireless network, at least one wired network, at least one optical network, or a combination thereof.

[0021] The measuring device 10 detects a marker M on the surface of the groove of the vehicle from an image of the vehicle, including the tire. The measuring device 10 calculates the remaining tread depth of the vehicle based on the detected marker M. In this embodiment, the measuring device 10 acquires an image of the vehicle by receiving it from the camera 20. The vehicle may include a tire or a crawler. In this embodiment, the vehicle is a tire. Tires include tires for cars, motorcycles, bicycles, airplanes, etc. The tire may also be an OR (Off-The-Road) tire mounted on a construction vehicle, mining vehicle, etc. In this embodiment, the groove surface is the groove wall W, but is not limited thereto. The groove surface also includes the groove bottom BT. The remaining tread depth may be the groove depth or the remaining tread volume. The remaining tread depth decreases as the tire wears with use. According to this embodiment, the remaining tread depth can be calculated from only an image of the vehicle, without the need for an operator to actually measure the remaining tread depth manually. The remaining tread depth of a vehicle, such as a tire, can be obtained more easily and at lower cost than manual measurement. Therefore, it is possible to improve the technology for measuring the remaining tread depth of a vehicle including tires.

[0022] <Measuring Device 10 > The measuring device 10 includes a control unit 11, a storage unit 12, a communication unit 13, and an input / output unit 14.

[0023] The control unit 11 includes at least one processor, at least one dedicated circuit, or a combination of these. The processor is a general-purpose processor such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit), or a dedicated processor specialized for a specific process. The dedicated circuit is, for example, an FPGA (Field-Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit). The control unit 11 controls each part of the measurement device 10 and executes processes related to the operation of the measurement device 10.

[0024] The storage unit 12 includes at least one semiconductor memory, at least one magnetic memory, at least one optical memory, or a combination of at least two of these. The semiconductor memory is, for example, a random access memory (RAM) or a read-only memory (ROM). The RAM is, for example, a static random access memory (SRAM) or a dynamic random access memory (DRAM). The ROM is, for example, an electrically erasable programmable read-only memory (EEPROM). The storage unit 12 functions as, for example, a main storage device, an auxiliary storage device, or a cache memory. The storage unit 12 stores any information, control / processing programs, etc. used in the operation of the measuring device 10, as well as information obtained by the operation of the measuring device 10.

[0025] The communication unit 13 includes at least one communication interface. The communication interface is, for example, a LAN interface, an interface compatible with a mobile communication standard such as the 4th Generation (4G) standard or the 5th Generation (5G) standard, an interface compatible with short-range wireless communication such as Bluetooth (registered trademark), or a LAN interface. The communication unit 13 receives information used in the operation of the measurement device 10 and transmits information obtained by the operation of the measurement device 10.

[0026] The input / output unit 14 includes at least one input / output interface. The input / output interface includes a touch screen integrated with a display. The input / output unit 14 accepts input operations for information used in the operation of the measuring device 10 and outputs information obtained by the operation of the measuring device 10. The input / output unit 14 may be connected to the measuring device 10 as an external input device instead of being provided in the measuring device 10. Any connection method, such as a Universal Serial Bus (USB), can be used. The input / output unit 14 may not be integrated, but may instead be composed of separate input and output units. In this case, the input unit includes at least one input interface, such as physical keys or a microphone. The output unit includes at least one output interface, such as a display or a speaker.

[0027] 2 to 6, the operation of the measurement device 10 will be described. This description of the operation corresponds to a measurement method executed by the measurement device 10.

[0028] In step S1, the control unit 11 acquires an image of the vehicle. The image is an image of the surface of the vehicle that is in contact with the ground. The image may be a two-dimensional image or a three-dimensional image. A three-dimensional image may be an RGB image in which information indicating depth is added to RGB values ​​(an RGBD image). In this example, the control unit 11 acquires an image captured by the camera 20 by receiving it from the camera 20.

[0029] In step S2, the control unit 11 detects a sign M provided on the wall W of the groove of the transportation means from the acquired image. Any method may be used to detect the sign M. In this example, the control unit 11 detects the sign M from the image using any image analysis technology. For example, the control unit 11 may acquire a trained model for detecting the sign M from an image, generated by machine learning, and detect the sign M using the trained model. The control unit 11 may detect the sign M based on the RGB values, HSV values, brightness values, or the like of each pixel in the two-dimensional image.

[0030] Fig. 3 shows an example of a three-dimensional image acquired by the control unit 11 in step S1. For example, the control unit 11 detects a sign M provided at a portion indicated by Z1 in Fig. 3. The sign M in Fig. 3 has a star shape as an example, but the shape of the sign M is not limited to this.

[0031] The control unit 11 may detect a marker MB provided on the bottom BT of the groove, which is the surface of the groove, instead of or in addition to the marker M provided on the wall W of the groove. For example, the control unit 11 detects a marker MB provided at the portion indicated by Z2 in FIG. 3. The marker MB in FIG. 3 has an oval shape as an example, but the shape of the marker MB is not limited to this. The marker MB may be formed by a protrusion protruding from the bottom BT or a recess carved into the bottom BT.

[0032] 4A and 4B show examples of the three-dimensional image acquired in step S1, and Fig. 4C shows examples of a marker M provided on a wall W of a groove of the tire T and a marker MB provided on a bottom BT of the groove, detected from the portion indicated by Z3 in the image of Fig. 4B. The hollow arrows in Fig. 4A and 4B indicate the width direction of the tire T. The dashed line in Fig. 4C shows an example of a cross-sectional profile P generated in the following step S5.

[0033] The marker M may be related to the groove depth. This allows for more accurate calculation of the remaining tread depth, as described below. In this example, the marker M is two parallel straight lines provided on the wall W of the groove, as shown in FIG. 4C. However, the marker M may also directly indicate the remaining tread depth, such as a scale in which the bottom BT of the groove is set to 0 and the numbers increase toward the surface of the tire T. In this case, the control unit 11 may output the number indicated by the marker M or a value corresponding to the number as the remaining tread depth in step S6. The marker M may have a different symbol or color depending on the remaining tread depth. The marker M may be formed by a protrusion protruding from the wall W or a recess carved into the wall W.

[0034] In step S3, the control unit 11 acquires characteristic information indicating the characteristics of the transportation means. In this example, the characteristic information includes any information indicating the characteristics of the tire T, such as the diameter, width, type, shape, etc. of the tire T. The control unit 11 may analyze the type of tire, etc. based on the image acquired in step S1 using any image analysis technology and acquire the analyzed information as characteristic information.

[0035] In step S4, the control unit 11 determines at least one of the number and spacing of the multiple cross-sectional profiles P to be generated based on characteristic information indicating the characteristics of the vehicle. This makes it possible to automatically generate many cross-sectional profiles for tires with long widthwise distances, for example, thereby improving the efficiency of analyzing the remaining tread depth using cross-sectional profiles suitable for various types of vehicle. For example, the control unit 11 reads information from the storage unit 12 that pre-associates the tire characteristics indicated by the characteristic information with the number or spacing of the cross-sectional profiles P, and determines at least one of the number and spacing of the cross-sectional profiles P based on the information. For example, if the information indicates that the spacing between the cross-sectional profiles P is X millimeters and the number of cross-sectional profiles is Y, associated with tire type A, the control unit 11 determines that the spacing between the cross-sectional profiles P to be generated is X millimeters and the number of cross-sectional profiles is Y. For example, the control unit 11 may determine a larger number of cross-sectional profiles P the wider the tire as the vehicle indicated by the characteristic information. The control unit 11 may also receive a value indicating the number or spacing of the cross-sectional profiles directly from the user via the input / output unit 14.

[0036] For example, the control unit 11 may determine to generate any number of cross-sectional profiles P at predetermined intervals in different directions in the width direction of the tire T from the position of the detected marker M. For example, the control unit 11 may read information indicating the number of cross-sectional profiles P to be generated per unit length of the marker M from the storage unit 12, and determine to generate the relevant number of cross-sectional profiles P.

[0037] In step S5, the control unit 11 generates a cross-sectional profile P that indicates the outline of the cross section of the vehicle at the position where the marker M was detected. This allows the use of a cross-sectional profile with a small amount of data, enabling efficient analysis of changes in the remaining groove amount. The control unit 11 generates the cross-sectional profile P using any image processing technique. In this example, the cross-sectional profile P is point cloud data or mesh data. If the image acquired in step S1 is a two-dimensional image, the control unit 11 may generate point cloud data using photogrammetry or the like.

[0038] In this example, the control unit 11 generates cross-sectional profiles P with the number and spacing determined in step S4, each having a plane perpendicular to a straight line L along the width direction of the tire T. As a result, as described below, when multiple cross-sectional profiles are generated at different positions in the width direction, the multiple cross-sectional profiles can be arranged to analyze changes in the remaining groove depth and easily grasp the wear trend of the surface of the vehicle. For example, the control unit 11 may generate, as the cross-sectional profile P, a line profile obtained by extracting point cloud data on the plane as a continuous line. FIG. 5 shows the position of the marker M detected in step S2 and the straight line L along the width direction of the tire T. As shown in FIG. 5, the control unit 11 generates cross-sectional profiles P1 to P5 in different directions in the width direction of the tire T at a predetermined interval I from the position of the marker M detected in C of FIG. 4. Each of the cross-sectional profiles P1 to P5 has a plane P51 perpendicular to the straight line L along the width direction of the tire T. The plane P51 in FIG. 5 represents a portion of the plane of the cross-sectional profile P. 5 show a portion of each contour of the cross-sectional profile P. The control unit 11 may generate the cross-sectional profile P based on the position of a marker MB instead of or in addition to the marker M.

[0039] Without being limited to this, the control unit 11 may generate an approximate plane or approximate curved surface from the surface of the tire T shown in the image using any image processing technology, and then generate a cross-sectional profile P having a plane perpendicular to the approximate plane.

[0040] When the three-dimensional image acquired in step S1 is point cloud data or mesh data, the control unit 11 may generate cross-sectional profiles P in areas of the point cloud data or mesh data where there is little or no loss. The control unit 11 may determine that there is no loss where the density of the point cloud data is equal to or greater than a predetermined value. The control unit 11 may increase the number of cross-sectional profiles P to be generated in the width direction up to the area where there is no loss in the point cloud data or mesh data, regardless of the number determined in step S4.

[0041] In this way, the control unit 11 generates, as at least one cross-sectional profile, a plurality of cross-sectional profiles at different widthwise positions of the tire T. This makes it easy to combine the multiple cross-sectional profiles to reconstruct them three-dimensionally, and to perform analysis and interpretation.

[0042] In step S6, the control unit 11 calculates the remaining tread depth. In this embodiment, the control unit 11 calculates the remaining tread depth based on the generated cross-sectional profile P. The control unit 11 calculates the remaining tread depth from the cross-sectional profile P using any image analysis technology. For example, the control unit 11 may detect a baseline between the recessed and protruding portions of the cross-sectional profile P, and calculate the peak-to-peak difference between the recessed and protruding portions as the remaining tread depth based on the baseline. For example, the control unit 11 may use polar coordinate conversion to represent the cross-sectional profile P using coordinate axes of the tire radius and deflection angle, and calculate the peak-to-peak difference between the recessed and protruding portions as the remaining tread depth.

[0043] The control unit 11 may calculate the groove depth as the remaining groove amount for each cross-sectional profile P, or may calculate the average value of the remaining groove amounts for each of the multiple cross-sectional profiles P generated as the remaining groove amount. The unit of groove depth as the remaining groove amount may be centimeters, millimeters, etc. When multiple cross-sectional profiles P are generated, the control unit 11 may calculate the volume of the groove as the remaining groove amount when lines corresponding to recesses in the radially inward direction of the tire in the multiple cross-sectional profiles P are connected to form a three-dimensional groove shape. The unit of the volume of the remaining groove amount may be cubic centimeters, etc. Figure 6 is a diagram showing an example of the overall configuration of a cross-sectional profile P1 generated by the control unit 11. Z3 in Figure 6 is a partial enlargement of the cross-sectional profile P1, and the groove depth RTD as the remaining groove amount calculated by the control unit 11 is indicated by a double-headed arrow.

[0044] The present invention is not limited to this, and any method may be adopted for calculating the remaining tread depth. For example, if the marker M is a marker having a color or shape related to the groove depth, the control unit 11 may calculate the remaining tread depth by reading information indicating the remaining tread depth from the storage unit 12, which associates the color or shape with the groove depth. For example, if the marker M is a marker indicating the groove depth with numbers or scale lines and is provided in parallel at different positions in the radial direction of the tire, as in the marker M shown in Figure 5, the control unit 11 may detect the value of the marker M provided radially outward from the image and calculate the remaining tread depth.

[0045] In step S7, the control unit 11 outputs the cross-sectional profile P and the calculated remaining groove amount. In this embodiment, the control unit 11 outputs the cross-sectional profile P generated in step S5 and the remaining groove amount calculated in step S6 via the input / output unit 14. This notifies the user of the cross-sectional profile P and the remaining groove amount. Thereafter, the processing operation of the control unit 11 ends.

[0046] <Program> A computer capable of executing program instructions can be used to function as the above-described measurement device 10. Here, the computer may be a general-purpose computer, a dedicated computer, a workstation, a personal computer (PC), an electronic notepad, etc. The program instructions may be program code, code segments, etc. for performing the necessary tasks.

[0047] The computer includes a processor, a storage unit, an input unit, an output unit, and a communication unit. The processor may be a CPU, an MPU, a GPU, a DSP (Digital Signal Processor), a SoC (System on a Chip), or the like, and may be configured with multiple processors of the same or different types. The processor controls the above components and performs various arithmetic processing by reading and executing a program from the storage unit. Note that at least a portion of these processing contents may be implemented by hardware. The input unit is an input interface that accepts user input operations and acquires information based on the user operations, such as a pointing device, keyboard, or microphone. The output unit is an output interface that outputs information, such as a display or speaker. The communication unit is a communication interface for communicating with external devices, such as a LAN interface.

[0048] The program may be recorded on a computer-readable recording medium. Using such a recording medium, the program can be installed on a computer. Here, the recording medium on which the program is recorded may be a non-transitory recording medium. The non-transitory recording medium is not particularly limited, and may be, for example, a CD-ROM, a DVD-ROM, or a USB (Universal Serial Bus) memory. Furthermore, the program may be downloaded from an external device via a network.

[0049] Although the above-described embodiments have been described as typical examples, it will be apparent to those skilled in the art that many modifications and substitutions are possible within the spirit and scope of the present disclosure. Therefore, the present disclosure should not be interpreted as being limited by the above-described embodiments, and various modifications and alterations are possible without departing from the scope of the claims. For example, multiple building blocks shown in the block diagrams of the embodiments may be integrated, or a single building block may be divided. Furthermore, multiple steps shown in the flowcharts of the embodiments may be integrated into one, or a single step may be divided. Contributing to the United Nations-led Sustainable Development Goals (SDGs)

[0050] The SDGs have been proposed to realize a sustainable society. One embodiment of the present invention is thought to be a technology that can contribute to goals such as "No. 9 - Build infrastructure for industry and technological innovation," "No. 12 - Responsible consumption and production," and "No. 13 - Take concrete action against climate change."

[0051] REFERENCE SIGNS LIST 10 Measuring device 11 Control unit 12 Storage unit 13 Communication unit 14 Input / output unit 20 Camera 30 Network

Claims

1. A measuring device comprising: a control unit that detects at least one mark provided on the surface of a groove of a moving means including tires from an image captured of the moving means; and calculates the remaining groove depth of the moving means based on the detected mark.

2. A measuring device according to claim 1, wherein said markings are markings related to the depth of said grooves.

3. A measuring device as claimed in claim 1 or 2, wherein the control unit generates, based on the image, at least one cross-sectional profile showing the outline of a cross section of the moving means at the position where the marker is detected.

4. A measuring device according to claim 3, wherein the cross-sectional profile has a plane perpendicular to a straight line along the width direction of the tire.

5. A measuring device according to claim 4, wherein the control unit generates a plurality of cross-sectional profiles at mutually different positions in the width direction as the at least one cross-sectional profile.

6. A measuring device according to claim 5, wherein the control unit determines at least one of the number and spacing of the multiple cross-sectional profiles to be generated based on characteristic information indicating characteristics of the moving means.

7. A measuring method executed by a computer, comprising: detecting a mark provided on the surface of a groove of a moving means from an image of the moving means; and calculating a remaining groove amount of the moving means based on the detected mark.

8. A program for causing a computer to function as the measuring device according to claim 1 or 2.

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