Wall crack measuring device and measuring method

Abstract

A crack measuring machine and method are provided that automate a series of operations related to the three-dimensional determination of cracks in a structure. The crack measuring machine (2) includes: a ranging unit (19, 20); an image capturing unit (21) where the position of each pixel on an image element is determined; an infrared image capturing unit (22) where the position of each pixel on an image element is determined and it is sensitive to infrared light; a drive unit (13, 14); an angle measuring unit (11, 12); and a calculation and control unit (18). The calculation and control unit (18) rotates the infrared image capturing unit (22), searches for cracks based on the temperature difference of the infrared image, captures an image of the crack by the image capturing unit (21), determines the position of the crack based on the density difference of the captured image, and determines the position of the crack by the ranging unit (19, 20) and the angle measuring unit (11, 12) to obtain the three-dimensional absolute coordinates of the crack.

Description

Technical Field

[0001] This invention relates to a measuring machine and a measuring method for determining cracks in the walls of structures. Background Technology

[0002] To investigate the distribution of cracks in large concrete structures such as buildings, bridges, and tunnels, a total station is used to measure distances and angles up to the measurement point. Previously, at the measurement site, scaffolding was erected, and workers would observe the cracks, mark and record the findings, or place reflective objects near the cracks for alignment – ​​all manual operations. In recent years, prism-less measurement has enabled alignment even without reflective objects; however, alignment of the target crack area still requires manual work and is time-consuming.

[0003] In contrast, for example, document 1 discloses a defect inspection device that includes an image capture unit and an infrared image capture unit. It determines the vicinity of a crack by using an infrared image, detects the vicinity of the crack by capturing an image, and determines the location and size of the crack by using the density difference of the image.

[0004] For example, document 1: Japanese Patent Application Publication No. 2010-216829 Summary of the Invention

[0005] However, for example, in the device described in Reference 1, there is a difficulty in registering the measured positions of the infrared image and the camera image. In other devices, establishing correlations between data acquired from multiple sensors also requires significant investigation and working time, and data processing is also necessary after the measurements.

[0006] The present invention was made in view of the following problems, and its object is to provide a crack measuring machine and measuring method that automates a series of operations related to the three-dimensional measurement of cracks in a structure.

[0007] To achieve the above objectives, a crack measuring machine according to one aspect of the present invention comprises: a ranging unit that emits ranging light toward a target object and receives reflected ranging light to measure the distance to the target object; an image capturing unit that determines the position of each pixel on an image element; an infrared image capturing unit that determines the position of each pixel on an image element and is sensitive to infrared light; a driving unit that rotates the ranging unit, the image capturing unit, and the infrared image capturing unit in the horizontal and vertical directions; an angle measuring unit that measures the horizontal and vertical rotation angles of the ranging unit, the image capturing unit, and the infrared image capturing unit; and a calculation and control unit that controls the ranging unit, the angle measuring unit, the image capturing unit, and the driving unit, wherein the calculation and control unit rotates the infrared image capturing unit, searches for cracks based on temperature differences in infrared images, captures images of the cracks using the image capturing unit, determines the position of the cracks based on density differences in the captured images, and obtains the three-dimensional absolute coordinates of the cracks by measuring the position of the cracks using the ranging unit and the angle measuring unit.

[0008] In the above-described manner, preferably, the image capturing unit and the infrared image capturing unit have an orthogonal coordinate system with the optical axis of the ranging light as the origin.

[0009] In the above method, it is preferable that the operation control unit performs multiple searches by progressively narrowing the temperature difference of the infrared image capturing unit.

[0010] In the above method, preferably, the calculation and control unit obtains three-dimensional absolute coordinates for the start point, inflection point, and end point of the crack.

[0011] In the above method, preferably, the calculation control unit determines the length and shape of the crack based on the three-dimensional absolute coordinates of the crack portion, and determines the thickness of the crack based on the number of pixels of the image capturing unit.

[0012] In the above-described manner, it is preferable that the ranging unit, the angle measuring unit, the image capturing unit, and the infrared image capturing unit are integrated into a single device.

[0013] Furthermore, one aspect of the crack detection method of the present invention includes the following steps: (a) rotating the infrared image capturing unit and searching for a crack based on the temperature difference of the infrared image; (b) taking an image of the crack found by the image capturing unit in step (a) and determining the position of the crack based on the density difference of the captured image; and (c) measuring the distance and angle of the position of the crack determined by the distance measuring unit and the angle measuring unit in step (b) to obtain three-dimensional absolute coordinates.

[0014] The effects of the invention

[0015] According to the crack measuring machine and method of the present invention, the three-dimensional measurement of cracks in a structure can be automated in a series of steps. Attached Figure Description

[0016] Figure 1 This is a perspective view of the measuring machine according to the implementation method.

[0017] Figure 2 This is a block diagram of the same measuring instrument.

[0018] Figure 3 This is a schematic diagram of the measurement work performed by the measuring machine.

[0019] Figure 4 This is the measurement flow chart for the same measuring instrument.

[0020] Figure 5 This is an example of an image processed by the same measuring instrument.

[0021] Figure 6 This is a schematic diagram of crack measurement performed using the same measuring machine.

[0022] Figure 7 This is an example of the results of crack testing performed using the same testing machine.

[0023] Explanation of symbols

[0024] 2. Measuring unit; 11. Horizontal angle detector (angle measuring unit); 12. Vertical angle detector (angle measuring unit); 13. Horizontal rotation drive unit; 14. Vertical rotation drive unit; 15. Display unit; 16. Operation unit; 17. Storage unit; 18. Calculation and control unit; 19. Distance measuring light emission unit (distance measuring unit); 20. Distance measuring light receiving unit (distance measuring unit); 21. Image capturing unit; 22. Infrared image capturing unit; 23. Infrared image diagnosis unit; 24. Crack image diagnosis unit Detailed Implementation

[0025] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings.

[0026] Figure 1 This is a perspective view of the measuring machine according to the embodiment. The crack measuring machine 2 (hereinafter referred to as measuring machine 2) is a total station. The measuring machine 2 includes: a base plate 2a disposed on a calibrator, a bracket 2b that rotates horizontally on the base plate 2a, a telescope 2c that rotates vertically at the center of the bracket 2b, and a display section 15 and an operation section 16 disposed in front of the bracket 2b.

[0027] Figure 2This is a block diagram of the measuring machine 2. The measuring machine 2 includes: a horizontal angle detector 11, a vertical angle detector 12, a horizontal rotation drive unit 13, a vertical rotation drive unit 14, a display unit 15, an operation unit 16, a storage unit 17, a calculation and control unit 18, a distance measuring light emitting unit 19, a distance measuring light receiving unit 20, an image capturing unit 21, and an infrared image capturing unit 22.

[0028] The horizontal rotation drive unit 13 and the vertical rotation drive unit 14 are motors controlled by the arithmetic control unit 18. The horizontal rotation drive unit 13 rotates the bracket unit 2b in the horizontal direction, and the vertical rotation drive unit 14 rotates the telescope 2c in the vertical direction.

[0029] The horizontal angle detector 11 and the vertical angle detector 12 are encoders. The horizontal angle detector 11 measures the horizontal rotation angle of the bracket 2b, and the vertical angle detector 12 measures the vertical rotation angle of the telescope 2a.

[0030] The display unit 15 has an LCD screen and allows for touchpad-style input. Images related to the measurement application are displayed on the LCD screen, and the operator performs the measurement under its guidance.

[0031] The operation unit 16 has number keys, decimal point keys, positive / negative keys, execute keys, scroll keys, etc., and can select, decide, or cancel the operations displayed on the display unit 15.

[0032] The ranging light emitting unit 19 is equipped with a light-emitting element and a light-transmitting optical system, and emits ranging light such as infrared laser towards the target object. The ranging light receiving unit 20 is equipped with a light-receiving element and a light-receiving optical system that shares optical elements with the aforementioned light-transmitting optical system, and receives the ranging light reflected from the target object.

[0033] The image capturing unit 21 is, for example, an assembly of pixels such as a CCD or CMOS sensor. In the image capturing unit 21, the position of each pixel on the image element is determined by orthogonal coordinates with the optical axis of the ranging light as the origin. The image capturing unit 21 is also used as an element constituting a tracking unit, which acquires both the lit and unlit images of the ranging light, detects the position of the target object based on their difference, and automatically tracks the target object at a position within a certain distance from the center of the line of sight of the telescope 2c. The tracking unit has an arbitrary configuration in this embodiment, so its description is omitted.

[0034] The infrared image capturing unit 22 uses a CCD or CMOS sensor, which is sensitive to infrared light, to capture images of the radiant heat emitted from the object being photographed, thus visualizing the temperature distribution of the object. In the infrared image capturing unit 22, the position of each pixel on the image element is determined using orthogonal coordinates with the optical axis of the ranging light as the origin.

[0035] The arithmetic control unit 18 is a control unit that integrates at least a CPU and memory (RAM, ROM, etc.) into an integrated circuit. The arithmetic control unit 18 calculates the distance to the target object based on the phase difference between the reflected ranging light and the reference light traveling along the reference light path provided in the optical system. Furthermore, it calculates the angle of the target object based on the measurements from the horizontal angle detector 11 and the vertical angle detector 12. The arithmetic control unit 18 also includes an infrared image diagnostic unit 23 and a crack image diagnostic unit 24. The infrared image diagnostic unit 23 performs data processing on the infrared image acquired by the infrared image capturing unit 22. The crack image diagnostic unit 24 performs data processing on the camera image acquired by the image capturing unit 21. This data processing will be described later.

[0036] The storage unit 17 is composed of, for example, a memory card or HDD. The storage unit 17 stores the measurement program performed by the arithmetic control unit 18. In addition, it records various information acquired by the arithmetic control unit 18.

[0037] The horizontal angle detector 11, vertical angle detector 12, horizontal rotation drive unit 13, vertical rotation drive unit 14, storage unit 17, and calculation control unit 18 are housed within the frame of the bracket unit 2b. The range-finding light emitting unit 19, range-finding light receiving unit 20, image capturing unit 21, and infrared image capturing unit 22 are housed within the frame of the telescope 2c. The range-finding light emitting unit 19, the range-finding light receiving unit 20, and the calculation control unit 18 constitute the range-finding unit. The horizontal angle detector 11, the vertical angle detector 12, and the calculation control unit 18 constitute the angle-finding unit. Regarding the configuration within the telescope 2c, the positional deviations of the image capturing unit 21 and the infrared image capturing unit 22 relative to the optical axis of the range-finding light in the horizontal and vertical directions are known in advance.

[0038] Figure 3 This is a schematic diagram of the measurement work performed by the measuring machine 2. The measuring machine 2 is set up at a known point using a tripod and adjusted to be horizontal relative to the setting surface by the calibration unit. After setting up the measuring machine 2, the operator connects the power supply to the measuring machine 2 and selects the crack measurement mode, then simply selects or inputs according to the application's guidance.

[0039] Figure 4 This is the measurement process flow chart for measuring machine 2.

[0040] After the crack measurement application begins, the current position (three-dimensional absolute coordinates) of the measuring machine 2 is first obtained by the calculation control unit 18 in step S101. If the current position is a known point, the coordinates are read from the storage unit 17. If it is not a known point, the system is guided to the measurement application obtained based on the current position obtained by the resection method, and then returns to this step.

[0041] Next, the process moves to step S102, where the infrared image diagnostic unit 23 operates. The infrared image diagnostic unit 23 uses infrared light to search for (find) cracks. In step S102, a coarse-range detection is first performed. While coordinating the horizontal rotation drive unit 13 and the vertical rotation drive unit 14, the infrared image diagnostic unit 23 uses the infrared image capturing unit 22 to roughly set the temperature difference (image color difference) (e.g., 10-degree units) and performs infrared measurement on the entire object under inspection. The coarse-range detection can be performed over a wide area using a wide-angle image or by sweeping across a narrow-angle image.

[0042] Next, the process moves to step S103, where the infrared image diagnostic unit 23 performs a mid-range detection. The infrared image diagnostic unit 23 targets the location where a temperature difference exists in the coarse-range detection. While coordinating the horizontal rotation drive unit 13 and the vertical rotation drive unit 14, the infrared image capturing unit 22 is used to measure the infrared radiation with the temperature difference set to be narrower than that in the coarse-range detection (e.g., 1 degree unit).

[0043] Next, the process moves to step S104, where the infrared image diagnostic unit 23 performs a fine-range detection. The infrared image diagnostic unit 23 targets the location where a temperature difference exists in the medium-range detection. While cooperating with the horizontal rotation drive unit 13 and the vertical rotation drive unit 14, the infrared image capturing unit 22 is used to measure the infrared radiation with the temperature difference set to be narrower than that in the medium-range detection (e.g., 0.1 degree units).

[0044] In this way, the measuring machine 2 appropriately changes the temperature difference of the infrared sensor while identifying the low-temperature section (the area with more moisture) as a crack and automatically searches for (finds) the crack. There is no limit to the number of times the coarse-range and medium-range detections are performed. For example, the coarse-range detection can be performed in units of decimeters to 1 meter, and the fine-range detection stage is set to meet the inspection criteria. Alternatively, the number of coarse-range and medium-range detections can be reduced by manually identifying the crack to a certain extent before starting, thereby shortening the search process.

[0045] Next, the process moves to step S105, where the crack image diagnosis unit 24 operates. The crack image diagnosis unit 24 performs image processing to determine the location of cracks. The crack image diagnosis unit 24 captures images of the detection locations where temperature differences exist in the fine-range detection using the image capturing unit 21. The detection locations of cracks detected by the infrared image capturing unit 22 are determined using orthogonal coordinates with the optical axis of the ranging light as the origin. Therefore, the crack image diagnosis unit 24 rotates at a specified angle determined in the fine-range detection by the infrared image capturing unit 22, and the image capturing unit 21 captures images in a manner that includes each crack. The crack image diagnosis unit 24 analyzes the density difference of the image from the high-resolution image at the pixel unit level to determine the location of the crack. Figure 5This is an example of an image processed by the measuring machine 2. Alternatively, the image of the crack obtained in step S105 can be displayed on the display unit 15 of the measuring machine 2 along with the sorting number.

[0046] Next, the process moves to step S106, where the crack image diagnosis unit 24 measures the crack. The crack image diagnosis unit 24 determines the coordinates of the crack's start point, inflection points (which can be multiple), and end point from the captured image of the crack from step S105, for example, through image processing that extracts endpoints and inflection points based on changes in contrast and color. The coordinates of the crack's start point, inflection points, and end point are located in the image acquisition unit 21 on an orthogonal coordinate system with the optical axis of the ranging light as the origin. Figure 6 This is a schematic diagram of crack measurement performed by the measuring machine 2, showing the determination of the crack's start point, inflection point, and end point. The crack image diagnostic unit 24 performs distance and angle measurement by emitting ranging light at each point while coordinating the horizontal rotation drive unit 13 and the vertical rotation drive unit 14. Then, the three-dimensional absolute coordinates of the crack's start point, inflection point, and end point are obtained.

[0047] Next, the process moves to step S107, where the crack image diagnostic unit 24 measures the size of the crack (measurement of crack length, shape, and thickness). Regarding the crack length and shape, the crack image diagnostic unit 24 measures them based on the three-dimensional absolute coordinates of the crack's start point, inflection point, and end point. Regarding the crack thickness, it is measured based on the number of pixels captured by the image acquisition unit 21. Figure 7 This is an example of the result of a crack test performed by the testing machine 2. The result is displayed on the display unit 15. Figure 7 As shown, the cracks are classified according to their length, shape, and thickness, and preferably displayed in different colors on the display unit 15. The data of the finished product displayed on the display unit 15 can also be transmitted to a CAD (Computer Aided Design) machine for drawing.

[0048] The measuring machine 2 according to this method automatically performs a series of measurement tasks related to the three-dimensional measurement of the crack, including crack search, crack location determination, crack location measurement (three-dimensional absolute coordinate measurement), and crack size measurement (crack length, shape, and thickness measurement).

[0049] Furthermore, the measuring machine 2 is a composite device that integrates a distance measuring optical rangefinder, an angle measuring theodolite, an image sensor, an infrared sensor, and image diagnostic functions into one unit. Therefore, it is easy to perform data processing that matches the positions of the objects acquired by each sensor. Thus, compared to devices that require setting up each sensor separately and establishing correlations for the data acquired by each sensor, it significantly reduces human working hours and errors.

[0050] Furthermore, according to measuring machine 2, the crack portion is measured in three dimensions on-site. This eliminates the hassle of bringing data back from the site and processing it with analytical software, thus shortening the construction or delivery period. Moreover, if the staff finds any deficiencies in the results after viewing them on-site, the crack portion can be measured again to address the shortcomings immediately. Therefore, the hassle of returning to the site is also avoided.

[0051] Furthermore, in the above embodiment, the ranging light emitting unit (ranging unit) 19, the image capturing unit 21, and the infrared image capturing unit 22 are position-matched with the optical axis of the ranging light as the origin. However, regarding the configuration within the telescope 2c, since the deviation values ​​in the horizontal and vertical directions relative to the optical axis of the ranging light are known, if the optical axis of the ranging light at each pixel is a known point other than the origin, the image capturing unit 21 and the infrared image capturing unit 22 can be position-matched by considering the deviation values. Moreover, it is preferable that the measuring machine 2 has the function of detecting and registering the deviation values ​​of the optical axes of the ranging light of the image capturing unit 21 and the infrared image capturing unit 22, and that the three origins are made consistent by adjusting the time variation before measurement.

[0052] The preferred crack testing machine and testing method of the present invention have been described above with embodiments and variations. However, various forms and variations can also be combined based on the knowledge of those skilled in the art, and such forms are also included within the scope of the present invention.

Claims

1. A crack testing machine, characterized in that, have: The ranging unit emits ranging light toward the target and receives reflected ranging light to determine the distance to the target. In the image capturing unit, the position of each pixel on the image element is determined; The infrared image capturing unit has the position of each pixel on the image element determined and is sensitive to infrared light; The driving unit causes the ranging unit, the image capturing unit, and the infrared image capturing unit to rotate in the horizontal and vertical directions. An angle measuring unit measures the horizontal and vertical rotation angles of the ranging unit, image capturing unit, and infrared image capturing unit; and The calculation and control unit controls the ranging unit, angle measuring unit, image capturing unit, infrared image capturing unit, and driving unit. The computation control unit, The infrared imaging unit is rotated to progressively narrow the temperature difference between the infrared imaging unit and the crack location is searched multiple times based on the temperature difference in the infrared image. The image capturing unit captures an image of the cracked area, and the location of the cracked area is determined based on the density difference in the captured image. The position of the crack is determined by the ranging unit and the angle measuring unit, and the three-dimensional absolute coordinates of the crack are obtained.

2. The crack testing machine as described in claim 1, The image capturing unit and the infrared image capturing unit have an orthogonal coordinate system with the optical axis of the ranging light as the origin.

3. The crack testing machine as described in claim 1 or 2, The calculation and control unit obtains the three-dimensional absolute coordinates of the start point, inflection point, and end point of the crack.

4. The crack testing machine as described in claim 1 or 2, The calculation and control unit determines the length and shape of the crack based on the three-dimensional absolute coordinates of the crack, and determines the thickness of the crack based on the number of pixels of the image capturing unit.

5. The crack testing machine as described in claim 1 or 2, The ranging unit, the angle measuring unit, the image capturing unit, and the infrared image capturing unit are integrated into one device.

6. A crack detection method, comprising the following steps: (a) Rotate the infrared image capturing unit and search for the crack based on the temperature difference in the infrared image; (b) Imaging the crack portion located by the image capturing unit in step (a), and determining the location of the crack portion based on the density difference of the image; and (c) The position of the crack determined by the ranging unit and the angle measuring unit in step (b) is measured by ranging and angle measuring to obtain three-dimensional absolute coordinates. In step (a), the temperature difference of the infrared image is narrowed in stages and multiple searches are performed.

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