Surface texture detection device, surface texture detection method, and surface texture detection program

Abstract

This invention provides a surface irregularity detection device, an irregularity detection method, and an irregularity detection program that can detect surface irregularities or steps between objects of various shapes with high precision. [Solution] The system comprises an illumination unit 12, an imaging unit 13, a detection unit 14, an angle switching unit 16, a control unit 17, and a moving unit 18. The illumination unit 12 illuminates the object 9 with slit light so that the illumination angle, which is the angle between the optical axis of the imaging unit 13 and the optical axis of the illumination unit 12, is greater than 45° and less than 90°. The imaging unit 13 photographs the object 9 illuminated by the slit light. The detection unit 14 analyzes the image captured by the imaging unit 13 in real time and detects steps or irregularities based on the shape of the slit light in the image. The angle switching unit 16 changes the illumination angle in real time within the range of greater than 45° and less than 90°. The control unit 17 controls the angle switching unit 16.

Description

Technical Field

[0003] , ,

[0001] The present invention relates to a technique for detecting the presence or absence of steps and the presence or absence of irregularities in civil engineering works such as shield tunnel construction, reinforced earth retaining wall method, and roadbed smoothness management.

Background Art

[0002] The shield method is a method of excavating a tunnel using a machine called a shield machine, and is often used when constructing a tunnel in an underground structure, a city with overcrowded traffic, or soft ground. In the shield method, a tunnel lining member made of precast concrete called a segment or segment ring is assembled one piece at a time in a ring shape at the excavated location, and the next excavation is advanced. However, in shield tunnel construction, steps may occur after the installation of segments, which may affect the structural integrity of the tunnel. Similarly, in reinforced earth retaining wall methods such as the tail arm method of reinforcing soil using steel materials, steps may occur during the installation of the wall surface material. It is important to detect these steps at an early stage and take appropriate measures. In addition, conventional step detection methods often rely on manual measurement, which requires time and labor. In road construction, since the smoothness of the roadbed affects the durability and riding comfort of the road, its management is also important.

[0003] Therefore, a method for detecting deformations that can detect concave deformations appearing on the surface of a structure is known (see Patent Document 1). This method generates distance images and visible images from data captured by the light section method, sets and integrates distance candidate areas and visible candidate areas from these, extracts deformations such as cracks, and calculates their shape, such as width and length. In the detection method of Patent Document 1, in order to reduce the probability of falsely detecting dirt on the surface of the object to be measured as a crack, it is necessary to set the angle between the camera optical axis and the illumination optical axis of the camera and slit light source used when taking images by the light section method to 10 to 30°. However, when the angle between the camera optical axis and the illumination optical axis is set to such an angle, false detections of dirt and other debris can be prevented, but there is a problem that cracks that should be detected may not be detected, resulting in a decrease in detection accuracy.

[0004] Furthermore, a measuring device for measuring the gap between segments of a segment ring is known (see Patent Document 2). This device uses an imaging device installed on the erector of a shield machine that rotates around the axis of the segment ring to capture an image from the inside of the segment ring in which the gaps between adjacent segments are captured as black line images, and calculates the width of the gaps between adjacent segments. In the measuring device of Patent Document 2, the incident angle of the optical axis of the linear bright area projector onto the inner surface of the segment ring is greater than 0° and less than 90°, and is preferably 45°.

[0005] However, depending on the surface shape and construction method of the object being measured, the presence and degree of unevenness, and the degree of steps between objects, can vary, and a 45° angle of incidence is not always appropriate. For example, if the surface of the object being measured has many normal and fine irregularities, or if the steps between objects tend to be large due to the construction method, a smaller angle of incidence can prevent false detections and allow for more accurate detection of irregularities. Conversely, if, for example, there are few normal and fine irregularities on the surface of the object being measured, or if the steps between objects tend to be small due to the construction method, a larger angle of incidence can allow for more accurate detection of irregularities. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2017-211314 [Patent Document 2] Japanese Patent Publication No. 2022-28202 [Overview of the project] [Problems that the invention aims to solve]

[0007] In view of these circumstances, the present invention aims to provide a surface irregularity detection device, an irregularity detection method, and an irregularity detection program that can detect irregularities or steps on the surface of objects having various shapes, or steps between objects, with high precision. [Means for solving the problem]

[0008] To solve the above problems, the present invention provides a surface irregularity detection device that detects irregularities in an object by irradiating the object with slit light from an irradiation unit and capturing an image with an imaging unit. The device comprises an irradiation unit that irradiates the object with slit light such that the irradiation angle, which is the angle between the optical axis of the imaging unit and the optical axis of the irradiation unit, is greater than 45° and less than 90°; an imaging unit that captures an image of the object irradiated with slit light; and a detection unit that analyzes the image captured by the imaging unit in real time and detects irregularities based on the shape of the slit light in the image. This enables high-precision detection of irregularities or steps in the surface shape of an object to be measured, as well as steps between objects. A known line laser can preferably be used for the irradiation unit. A known RGB camera can preferably be used for the imaging unit, but other cameras may also be used. The imaging unit preferably captures moving images, but it may also capture still images. The irregularities detected by the detection unit include not only the irregularities of the surface shape of the object being measured, but also the steps between objects. Therefore, in this specification, "irregularities" may also be used to mean not only the "irregularities" of the surface shape of the object, but also the "steps" between objects. The detection unit may be configured to detect only the surface irregularities of the object being measured, or to detect only the steps between objects, or to detect both the surface irregularities of the object being measured and the steps between objects. In particular, in the case of a configuration that includes a discrimination unit as described later, the detection unit is configured to detect both the surface irregularities of the object being measured and the steps between objects. The irradiation angle, which is the angle between the optical axis of the imaging unit and the optical axis of the slit light, should not be 45° or less, as this makes it difficult to detect fine irregularities and reduces detection accuracy. Conversely, if it is 90° or more, it becomes difficult to measure the surface of a nearly flat object, so the angle should be kept within this range.

[0009] The surface irregularity detection device of the present invention preferably further comprises an angle switching unit that changes the irradiation angle within a range of more than 45° and less than 90°, and a control unit that controls the angle switching unit. By reducing the irradiation angle, minute irregularities that do not affect the safety of the object being measured can be excluded from the detection target. Conversely, by increasing the irradiation angle, irregularities that affect the safety of the object being measured can be represented more clearly in the image, improving detection accuracy. It is preferable that the irradiation angle can be switched in real time, which makes it possible to quickly and accurately detect important irregularities according to the conditions of the measurement site.

[0010] In the surface irregularity detection device of the present invention, the control unit may perform control to reduce the irradiation angle when the number of irregularities detected from a single image by the detection unit exceeds a first threshold, and control to increase the irradiation angle when it falls below a second threshold, which is a value smaller than the first threshold. Generally, precast members (segments) used in shield tunnel construction and other applications have a limited range of irregularities that occur during manufacturing. Therefore, if irregularities exceeding a threshold set according to the material of the object being measured are detected, it is highly likely that the system is detecting too many irregularities within the normal range, rather than abnormal ones. To address this, a first threshold is set, and if irregularities exceeding this threshold are detected, the irradiation angle is reduced to decrease the detection accuracy. Conversely, if too few irregularities are detected, it is possible that not only normal irregularities but also abnormal ones are not being detected. To address this, a second threshold is set, and if irregularities below this threshold are detected, the irradiation angle is increased to improve the detection accuracy. The number of the first or second thresholds can be appropriately set according to the type and purpose of measurement, the material and shape of the structure being measured, etc.

[0011] The surface irregularity detection device of the present invention may further include a discrimination unit that determines whether or not there are steps and whether or not there are abnormal irregularities. Regarding the presence or absence of steps, if a step is detected by the detection unit, it is determined that a step exists. In contrast, for irregularities other than steps, the detection unit distinguishes between normal irregularities that do not affect the safety of the object being measured and abnormal irregularities that do have an impact. The reason why steps and other irregularities are processed differently is that even minute steps can cause a large step to occur when many of them are present. On the other hand, minute irregularities are often just dirt adhering to the surface of the object and are unlikely to cause large displacements like steps. Therefore, depending on the type, size, and shape of the object being measured, the system may also be configured to distinguish between normal steps that do not affect the safety of the object being measured and abnormal steps that do have an impact.

[0012] In the surface irregularity detection device of the present invention, the control unit may control the irradiation angle to decrease if the number of irregularities identified as normal irregularities (not steps or abnormal irregularities) exceeds a third threshold, and to increase the irradiation angle if it falls below a fourth threshold, which is smaller than the third threshold. Here, normal irregularities refer to irregularities other than steps that do not affect the safety of the object being measured. Furthermore, the "number of irregularities detected from one image" is preferably the total number of irregularities including steps, but depending on the type and purpose of measurement, the material and shape of the structure being measured, etc., it may be, for example, the sum of the number of normal irregularities and the number of abnormal irregularities. As mentioned above, precast members used in shield tunnel construction and other applications generally have irregularities that occur during manufacturing limited to a certain range. Therefore, a third threshold is set, and if normal irregularities exceeding this threshold are detected, it is highly likely that too many normal irregularities are being detected, so the irradiation angle is reduced to decrease the detection accuracy. Furthermore, a fourth threshold is set, and if irregularities below this threshold are detected, it is possible that too few normal irregularities are being detected, so the irradiation angle is increased to improve the detection accuracy. The number of the third or fourth thresholds can be set as appropriate depending on the type and purpose of measurement, the material and shape of the structure being measured, etc.

[0013] The surface irregularity detection device of the present invention may also include a moving unit that moves at least the illumination unit and the imaging unit simultaneously. This makes it easy to perform continuous measurements while changing the measurement location. The direction of movement of the moving unit and the amount of movement per measurement can be appropriately set according to the type and purpose of measurement, the material and shape of the structure to be measured, etc.

[0014] The unevenness detection method of the present invention is a method for irradiating an object with slit light from an irradiation unit and taking a photograph with an imaging unit to detect the unevenness of the object. The computer irradiates slit light from the irradiation unit such that the irradiation angle, which is the angle formed by the optical axis of the imaging unit and the optical axis of the irradiation unit, exceeds 45° and is less than 90°. The method includes an irradiation step, an imaging step of imaging the object irradiated with the slit light using the imaging unit, and a detection step of analyzing the image captured in the imaging step in real time and detecting the unevenness based on the shape of the slit light in the image.

[0015] The unevenness detection program of the present invention causes a computer to execute all the steps in the above unevenness detection method.

Effects of the Invention

[0016] According to the unevenness detection device, unevenness detection method, and unevenness detection program of the present invention, there is an effect that unevenness or a step between objects can be detected with high accuracy for the unevenness of the surface shape of an object having various shapes.

Brief Description of the Drawings

[0017] [Figure 1] Functional block diagram of the unevenness detection device of Example 1 [Figure 2] Usage image diagram of the unevenness detection device of Example 1 (left side view) [Figure 3] Usage image diagram of the unevenness detection device of Example 1 (front view)<000,0087> [Figure 4] Step detection image diagram [Figure 5] Convex part detection image diagram [Figure 6] Concave part detection image diagram [Figure 7] Explanation diagram of the angle switching unit [Figure 8] Angle switching image diagram regarding the step [Figure 9] Angle switching explanation diagram regarding the unevenness <0000,100> Flow chart of the unevenness detection method of Example 1 [Figure 11]Functional block diagram of the unevenness detection device of Example 2 [Figure 12] Flowchart of the surface irregularity detection method in Example 2 [Modes for carrying out the invention]

[0018] Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings. It should be noted that the scope of the present invention is not limited to the following embodiments or illustrated examples, and numerous modifications and variations are possible. [Examples]

[0019] Figure 1 shows a functional block diagram of the surface unevenness detection device of Embodiment 1. As shown in Figure 1, the surface unevenness detection device 1 of Embodiment 1 comprises an illumination unit 12, an imaging unit 13, a detection unit 14, an angle switching unit 16, a control unit 17, and a moving unit 18. The illumination unit 12 irradiates the object 9 with slit light so that the irradiation angle, which is the angle between the optical axis of the imaging unit 13 and the optical axis of the irradiation unit 12, is greater than 45° and less than 90°. A known line laser can be suitably used. The imaging unit 13 photographs the object 9 irradiated with slit light, and a known RGB camera can be suitably used. The detection unit 14 analyzes the image captured by the imaging unit 13 in real time and detects steps or irregularities based on the shape of the slit light in the image. The angle switching unit 16 changes the irradiation angle in real time within the range of greater than 45° and less than 90°. The control unit 17 controls the angle switching unit. Examples of objects 9 include precast members used in shield tunnel construction and reinforced earth wall construction.

[0020] Figure 2 or Figure 3 is an illustrative diagram of the use of the surface irregularity detection device of Example 1, with Figure 2 showing a left side view and Figure 3 showing a front view. Figure 4 also shows an illustrative diagram of step detection. As shown in Figure 2, the surface irregularities of the object (9a, 9b) are detected using the surface irregularity detection device 1. Camera 3 functions as an imaging unit 13 and photographs the surface of the object (9a, 9b) to be measured from a vertical direction. Line laser 2 functions as an illumination unit 12 and irradiates the object (9a, 9b) with slit light 20. The irradiation angle θ, which is the angle between the optical axis 30 of camera 3 and the optical axis of slit light 20, is set to be greater than 45° and less than 90°. As shown in Figure 3, a step 90 is created between object 9a and object 9b, and as shown in Figure 4, linear portions 5 appear in the image 7a captured by camera 3 due to the laser light 20 shining on the objects (9a,9b).

[0021] The detection unit 14 of the surface irregularity detection device 1 detects linear portions 5 from the captured image 7a and detects irregularities from the position coordinates of the endpoints (A1, A2) of the linear portions 5 shown in Figure 4 and the shape of the linear portions 5. The detection unit 14 may be configured to detect steps or to detect irregularities other than steps.

[0022] (Regarding the detection of steps) First, the mechanism by which the detection unit 14 detects the step will be explained with reference to Figures 2 and 4. In the example shown in Figure 4, the linear section 5 is divided into two linear sections (5a, 5b) at the step 90. In this case, if we let W be the amount of displacement between the cutting point B1 of linear section 5a and the cutting point B2 of linear section 5b, and let θ be the irradiation angle which is the angle between the optical axis 30 of the camera 3 and the optical axis of the slit light 20 as described above, then the step amount H shown in Figure 2 can be expressed by the following equation 1.

[0023] (Math 1) H = W / tanθ ···(Equation 1)

[0024] (Regarding the detection of uneven surfaces) Next, the mechanism by which the detection unit 14 detects uneven shapes other than steps will be explained. Figure 5 is an image diagram of the protrusion detection, where (1) is a cross-sectional image and (2) is an image diagram of the protrusion detection. As shown in Figure 5(1), if there are protrusions 91 with a roughly semicircular cross-section or protrusions 92 with corners on the surface of the object 9, when the object 9 is photographed by the camera 3, the slit light 20 will appear as a linear or deformed area, as shown in the captured image 7b in Figure 5(2). Specifically, as shown in Figure 5(2), linear section 5c forms from endpoint A1 to displacement endpoint C1, linear section 5d forms from displacement endpoint C2 to cutting point B3, and linear section 5e forms from cutting point B6 to endpoint A2. Since the linear sections (5c~5e) lie on a straight line connecting endpoint A1 and endpoint A2, the detection unit 14 recognizes the linear sections (5c~5e) as linear sections without displacement. The curved displacement section 6a, formed below the linear section (5c~5e), forms from displacement endpoint C1 to displacement endpoint C2 and represents the convex section 91. Similarly, the straight displacement section 6b, formed below the linear section (5c~5e), forms from cutting point B4 to cutting point B5 and represents the convex section 92. Since neither the curved displacement section 6a nor the straight displacement section 6b lies on the straight line connecting endpoint A1 and endpoint A2, the detection unit 14 recognizes the displacement sections (6a, 6b) as displacement sections.

[0025] Figure 6 is an image diagram of recess detection, where (1) is a cross-sectional image and (2) is an image diagram of recess detection. As shown in Figure 6(1), if a recess 95 with a roughly semicircular cross-section or a recess 96 with a vertically cut-out is present on the surface of the object 9, when the object 9 is photographed with the camera 3, the slit light 20 will appear as a linear or deformed area, as shown in the captured image 7c in Figure 6(2). Specifically, as shown in Figure 6(2), linear section 5c forms from endpoint A1 to displacement endpoint C1, linear section 5d forms from displacement endpoint C2 to cutting point B3, and linear section 5e forms from cutting point B6 to endpoint A2. Since the linear sections (5c~5e) lie on a straight line connecting endpoint A1 and endpoint A2, the detection unit 14 recognizes the linear sections (5c~5e) as linear sections without displacement. The curved displacement section 6c, formed above the linear section (5c~5e), forms the area from displacement endpoint C1 to displacement endpoint C2 and represents the recess 95. Similarly, the straight displacement section 6d, formed above the linear section (5c~5e), forms the area from cutting point B7 to cutting point B8 and represents the recess 96. Since neither the curved displacement section 6c nor the straight displacement section 6d lies on the straight line connecting endpoint A1 and endpoint A2, the detection unit 14 recognizes the displacement sections (6c, 6d) as displacement sections.

[0026] Furthermore, if the detection unit 14 detects uneven shapes other than steps, the step amount H of the displacement section (6a to 6d) can also be calculated using the above-described formula 1, in the same way as when detecting steps.

[0027] (Regarding switching the irradiation angle) Next, the switching of the irradiation angle will be explained with reference to Figures 7 to 9. The unevenness detection device 1 includes an angle switching unit 16 and a control unit 17 that controls the angle switching unit 16. There are two main reasons for switching the irradiation angle. One is to increase the irradiation angle to detect important steps and unevenness that have a particularly significant impact on the safety of structures with higher accuracy. The other is to decrease the irradiation angle to prevent false detection of minute steps and unevenness that have little impact on the safety of structures, such as dirt adhesion, and to focus on detecting more important steps and unevenness, as well as to achieve faster image processing.

[0028] Figure 7 shows an explanatory diagram of the angle switching unit. As shown in Figure 7, the irradiation angle of the slit light 20 can be easily changed by changing the angle of the line laser 2. The angle switching unit 6 can change the slit light 20 in real time within a range that exceeds the irradiation angle θ1 and is less than the irradiation angle θ2. In this embodiment, the irradiation angle θ1 is set to 45.5° and the irradiation angle θ2 is set to 89.5°, but depending on the type of object, measurement location, size of the device, etc., the irradiation angle θ1 can be appropriately set within a range that exceeds 45° and the irradiation angle θ2 is less than 90°.

[0029] Figure 8 is an image diagram illustrating the angle switching related to the step difference, where (1) shows the case when the irradiation angle is small and (2) shows the case when the irradiation angle is large. When the irradiation angle is small, as shown by the irradiation angle θ1 in Figure 7, the amount of displacement W1 between the cutting point B1 of the linear part 5a and the cutting point B2 of the linear part 5b becomes smaller than the amount of displacement W shown in Figure 4, as shown in Figure 8(1). In contrast, when the irradiation angle is large, as shown by the irradiation angle θ2 in Figure 7, the amount of displacement W2 between the cutting point B1 of the linear part 5a and the cutting point B2 of the linear part 5b becomes larger than the amount of displacement W shown in Figure 4, as shown in Figure 8(2).

[0030] If the displacement W between the cutting point B1 of the linear section 5a and the cutting point B2 of the linear section 5b becomes too small, the detection unit 14 may find that the displacement W falls below the step detection limit, and therefore cannot detect it as a step. Therefore, even if the step is minute, if it has a significant impact on the safety of the structure, the system is configured to detect it by increasing the irradiation angle. Furthermore, it is desirable to exclude minute steps that do not affect the safety of the structure from detection. In such cases, by reducing the irradiation angle, the amount of step displacement W falls below the step detection limit, making it easy to exclude them from detection.

[0031] Figure 9 is an explanatory diagram of angle switching related to unevenness, where (1) is a cross-sectional image, (2) is an image of the detection of unevenness when the irradiation angle is increased, and (3) is an image of the detection of unevenness when the irradiation angle is decreased. As shown in Figure 9(1), the object 9 has a protrusion 93 with a roughly semicircular cross-section, a protrusion 94 with corners, a recess 97 with a roughly semicircular cross-section, and a recess 98 with a vertically cut-out. The protrusions (93,94) and recesses (97,98) are all fine irregularities that do not affect the safety of the structure. As shown in Figure 7, when the irradiation angle is increased, as in irradiation angle θ2, the displacement amount W3 of the convex portion (93,94) and the displacement amount W4 of the concave portion (97,98) increase, as shown in Figure 9(2). Conversely, when the irradiation angle is decreased, as in irradiation angle θ1 shown in Figure 7, the displacement amount W5 of the convex portion (93,94) and the displacement amount W6 of the concave portion (97,98) decrease, as shown in Figure 9(3).

[0032] Regarding irregularities other than steps, if the displacement amount W becomes too small, the detection unit 14 may not be able to detect them as irregularities because the displacement amount W falls below the irregularity detection limit. Therefore, even if the irregularities are minute, if they have a significant impact on the safety of the structure, the system is configured to detect them by increasing the irradiation angle. Furthermore, it is desirable to exclude minute irregularities that do not affect the safety of the structure from detection. In such cases, by reducing the irradiation angle, the displacement amount W of the convex parts (93, 94) and concave parts (97, 98) falls below the irregularity detection limit, making it easy to exclude them from detection.

[0033] (Flowchart for detecting uneven surfaces) The method of using the surface irregularity detection device 1 will be explained with reference to Figure 10. Figure 10 shows a flowchart of the surface irregularity detection method of Embodiment 1. As shown in Figure 10, first, the line laser 2 and camera 3 are moved simultaneously using the movable part 18 of the surface irregularity detection device 1 to determine the measurement location of the object 9 (step S01). In this state, the object 9 is irradiated with slit light 20 using the line laser 2 (step S02) and the object 9 is photographed using the camera 3 (step S03).

[0034] The detection unit 14 detects irregularities in the image captured by the camera 3 (step S04). The control unit 17 then determines whether the number of irregularities exceeding the first threshold has been detected (step S05). If the number of irregularities exceeding the first threshold has been detected, it determines whether the irradiation angle has not reached the lower limit (step S06). If the irradiation angle has not reached the lower limit, the control unit 17 controls the angle switching unit 16 to change the irradiation angle θ of the line laser 2 to a smaller value (step S07), and once again, the camera 3 is used to photograph the object 9 while irradiating it with slit light 20 using the line laser 2 (step S02) (step S03). In contrast, if the irradiation angle has reached the lower limit, the irradiation angle is not changed, and a determination is made as to whether all imaging has been completed (step S11). If all imaging has not been completed, the moving unit 18 moves the line laser 2 and camera 3 simultaneously again to determine the measurement location of the object 9 (step S01).

[0035] Furthermore, in step S05, if no number of irregularities exceeding the first threshold is detected, the next step is to determine if no number of irregularities below the second threshold is detected (step S08). If a number of irregularities below the second threshold is detected, the next step is to determine if the irradiation angle has reached the upper limit (step S09). If the irradiation angle has not reached the upper limit, the irradiation angle θ of the line laser 2 is increased further (step S10), and the object 9 is again irradiated with slit light 20 using the line laser 2 (step S02), while the object 9 is photographed using the camera 3 (step S03). In contrast, if the irradiation angle reaches the upper limit in step S09, or if the number of irregularities below the second threshold is not detected in step S08, the irradiation angle is not changed, and a determination is made as to whether all imaging is complete (step S11). If all imaging is not complete, the moving unit 18 moves the line laser 2 and camera 3 simultaneously again to determine the measurement points of the object 9 (step S01).

[0036] In step S11, if all shooting is completed, the measurement is finished. Furthermore, the number of the first or second threshold, the magnitude of the angle when changing the irradiation angle of line laser 2, and the upper and lower limits of the irradiation angle can be set as appropriate depending on the type and purpose of measurement, the material and shape of the structure to be measured, etc. [Examples]

[0037] Figure 11 shows a functional block diagram of the surface unevenness detection device of Embodiment 2. As shown in Figure 11, the surface unevenness detection device 1a of Embodiment 2 comprises an illumination unit 12, an imaging unit 13, a detection unit 14a, a discrimination unit 15, an angle switching unit 16, a control unit 17a, and a movement unit 18. Unlike the surface unevenness detection device 1 of Embodiment 1, the surface unevenness detection device 1a of Embodiment 2 comprises a detection unit 14a, a discrimination unit 15, and a control unit 17a. The detection unit 14a analyzes the image captured by the imaging unit 13 in real time and detects steps and irregularities based on the shape of the slit light in the image. Unlike the irregularity detection device 1 of Example 1, it has a structure that detects both steps and irregularities other than steps.

[0038] Based on the unevenness detection results from the detection unit 14a, the discrimination unit 15 determines whether there are steps or abnormal unevenness. Regarding the presence or absence of steps, if steps are detected by the detection unit 14a, it is determined that there are steps. In contrast, for unevenness other than steps, the detection unit 14a distinguishes between normal unevenness that does not affect the safety of the object being measured and abnormal unevenness that does have an effect. The reason why steps and unevenness other than steps are processed differently is that even minute steps can result in a large step due to numerous minute steps, depending on the shape and number of objects and construction conditions such as the construction method, which can lead to construction defects. On the other hand, minute unevenness is often just dirt adhering to the surface of the object and is unlikely to cause large displacements like steps. Therefore, depending on the type, size, and shape of the object being measured, the system may also be configured to distinguish between normal steps that do not affect the safety of the object being measured and abnormal steps that do have an impact.

[0039] The control unit 17a controls the irradiation angle to decrease if the number of irregularities identified as normal irregularities (not steps or abnormal irregularities) by the discrimination unit 15 from a single image exceeds a third threshold, and increases the irradiation angle if it falls below a fourth threshold, which is smaller than the third threshold. The "number of irregularities detected from a single image" used to determine the third or fourth threshold is the total number of irregularities, including steps, in order to improve detection accuracy. The configuration of the illumination unit 12, imaging unit 13, angle switching unit 16, or moving unit 18 is the same as in Embodiment 1.

[0040] The method of using the surface irregularity detection device 1a will be explained with reference to Figure 12. Figure 12 shows a flowchart of the surface irregularity detection method of Embodiment 2. As shown in Figure 12, first, the line laser 2 and camera 3 are moved simultaneously using the movable part 18 of the surface irregularity detection device 1a to determine the measurement location of the object 9 (step S101). In this state, the object 9 is irradiated with slit light 20 using the line laser 2 (step S102) and the object 9 is photographed using the camera 3 (step S103).

[0041] The detection unit 14a detects irregularities in the image captured by the camera 3 (step S104). The discrimination unit 15 determines whether there are steps or abnormal irregularities in the detected irregularities (step S105). At this point, the control unit 17a determines whether the number of normal irregularities exceeding the third threshold has been detected (step S106). If the number of irregularities exceeding the third threshold has been detected, it determines whether the irradiation angle has not reached the lower limit (step S107). At this point, if the irradiation angle has not reached the lower limit, the control unit 17a controls the angle switching unit 16 to change the irradiation angle θ of the line laser 2 to a smaller value (step S108), and again, while irradiating the object 9 with slit light 20 using the line laser 2 (step S102), the object 9 is photographed using the camera 3 (step S103). In contrast, if the irradiation angle has reached the lower limit, the irradiation angle is not changed, and a determination is made as to whether all imaging has been completed (step S112). If all imaging has not been completed, the moving unit 18 moves the line laser 2 and camera 3 simultaneously again to determine the measurement location of the object 9 (step S101).

[0042] Furthermore, in step S106, if no normal irregularities exceeding the third threshold are detected, the next step is to determine if no normal irregularities below the fourth threshold are detected (step S109). If no normal irregularities below the fourth threshold are detected, the next step is to determine if the irradiation angle has reached its upper limit (step S110). If the irradiation angle has not reached its upper limit, the irradiation angle θ of the line laser 2 is increased further (step S111), and the object 9 is again irradiated with slit light 20 using the line laser 2 (step S102), while the object 9 is photographed using the camera 3 (step S103). In contrast, if the irradiation angle reaches the upper limit in step S110, or if the number of normal irregularities below the fourth threshold is not detected in step S109, the irradiation angle is not changed, and a determination is made as to whether all imaging is complete (step S112). If all imaging is not complete, the moving unit 18 moves the line laser 2 and camera 3 simultaneously again to determine the measurement points of the object 9 (step S101).

[0043] In step S112, if all shooting is completed, the measurement is finished. Furthermore, the third or fourth threshold number, the magnitude of the angle when changing the irradiation angle of line laser 2, and the upper and lower limits of the irradiation angle can be set as appropriate depending on the type and purpose of measurement, the material and shape of the structure being measured, etc.

[0044] (Other examples) 1) Unlike Embodiment 1, in which the object 9 is photographed from above using camera 3, the camera 3 may be configured to photograph from the side or upward. For example, by configuring camera 3 to photograph from the side, the unevenness detection device of the present invention can be used to detect steps and unevenness in reinforced earth wall construction methods such as the Tail Armée method, which uses steel materials to reinforce the soil. Also, by configuring camera 3 to photograph from above or to the side, the unevenness detection device of the present invention can be used to detect steps and unevenness after the installation of segments in shield tunnel construction. 2) The direction of movement of the movable part 18 is not limited to the direction indicated by the arrow in Figure 2, and it may be configured to move up, down, left, and right according to the surface shape of the object 9. Furthermore, when the unevenness detection device of the present invention is used in shield tunnel construction, it may be configured to move in a rotational manner around the axis of the tunnel. [Industrial applicability]

[0045] This invention is useful as a technology for detecting the presence or absence of steps or unevenness in civil engineering works such as shield tunnel construction, reinforced earth wall construction, and roadbed smoothness management. [Explanation of symbols]

[0046] 1,1a Surface unevenness detection device 2-line laser 3 cameras 5,5a~5e Linear part 6a~6h Displacement section 7a~7g Acquired Images 9,9a,9b Object 12 Lighting Section 13 Imaging Unit 14,14a Detection unit 15 Discrimination part 16 Angle switching section 17,17a Control Unit 18. Mobile section 20 Slit Light 30 Optical axis 90 steps 91-94 Convex part 95~98 recess A1,A2 end points B1~B8 cutting point C1, C2 displacement endpoints H Step amount W, W1~W6 displacement amount θ, θ1, θ2 irradiation angle

Claims

1. A device for detecting the irregularities of an object by irradiating it with slit light from an irradiation unit and taking a picture of it with an imaging unit, An irradiation unit that irradiates the object with the slit light such that the irradiation angle, which is the angle between the optical axis of the imaging unit and the optical axis of the irradiation unit, is greater than 45° and less than 90°, An imaging unit that photographs the object onto which the slit light is irradiated, A detection unit analyzes the image captured by the imaging unit in real time and detects irregularities based on the shape of the slit light in the image. An unevenness detection device characterized by comprising the following features.

2. An angle switching unit that changes the irradiation angle within a range of more than 45° and less than 90°, Control unit for controlling the angle switching section, The unevenness detection device according to claim 1, further comprising the following:

3. The control unit, The number of bumps and depressions detected from a single image by the detection unit is If the first threshold is exceeded, control is performed to reduce the irradiation angle. The surface irregularity detection device according to claim 2, characterized in that it controls the irradiation angle to be increased when it falls below a second threshold value which is smaller than a first threshold value.

4. The unevenness detection device according to claim 2, further comprising a discrimination unit for determining whether there is a step or abnormal unevenness in the aforementioned unevenness.

5. The control unit, With respect to the number of irregularities detected from a single image by the discrimination unit, the number of irregularities that are determined to be normal irregularities, rather than steps or abnormal irregularities, is If the third threshold is exceeded, control is performed to reduce the irradiation angle. The surface irregularity detection device according to claim 4, characterized in that it controls the irradiation angle to be increased when the value falls below a fourth threshold, which is a value smaller than a third threshold.

6. The surface irregularity detection device according to claim 1, further comprising a moving unit that moves at least the irradiation unit and the imaging unit simultaneously.

7. A method for detecting the irregularities of an object by irradiating it with slit light from an irradiation unit and taking a picture of it with an imaging unit, Computers An irradiation step in which the slit light is irradiated from the irradiation unit such that the irradiation angle, which is the angle between the optical axis of the imaging unit and the optical axis of the irradiation unit, is greater than 45° and less than 90°, The imaging step involves photographing the object irradiated with the slit light using the imaging unit, A detection step involves analyzing the image captured in the above imaging step in real time and detecting irregularities based on the shape of the slit light in the image. A method for detecting unevenness, characterized by comprising the following features.

8. A surface irregularity detection program that causes a computer to perform all the steps in the surface irregularity detection method of claim 7.

Images