Patent Application
20220276181
The present disclosure relates to surface anomaly detecting devices, systems, methods, and non-transitory computer-readable media, and relates in particular to a surface anomaly detecting device, a system, a method, and a non-transitory computer-readable medium that can identify an anomalous portion on a surface of a complex structure.
In a facility within an establishment, a deteriorated portion appearing in a surface of the facility's structure, such as a portion that has rusted or where the paint has peeled off due to aging or corrosion, is highly likely to lead to damage or corruption of the facility in the near future. Currently, such an anomalous portion on a surface is often identified and determined through visual inspection, but an inspector may miss an anomalous portion or makes a subjective determination, and also from the standpoint of workload of sending an inspector, the importance of a system for automatically identifying an anomalous portion is on the rise. A laser range-finding (Light Detection and Ranging (LiDAR)) device can acquire a three-dimensional structure of an object (a structure) and is often equipped with a function of measuring the luminance of the received laser light as well as the position information of points on the surface of the three-dimensional object. Typically, the luminance of received light, that is, the reflection luminance from an object is dependent on the condition of the surface of the object irradiated by a laser. Therefore, an anomalous portion on a surface, such as rusting or peeling of paint, can be detected by processing information indicating the luminance of received light acquired by a laser range-finding device. However, an attempt to identify an anomalous portion on a surface of a complex structure sometimes leads to a false detection or the like. In the present disclosure, the luminance of received light acquired by a laser range-finding device is referred to below as “reflection luminance.”
Patent Literature 1 discloses a surface defect detecting device that includes a feature amount calculating unit, a threshold setting unit, and a defect detecting unit. The feature amount calculating unit calculates a feature amount with respect to a luminance frequency distribution of an image obtained through imaging, based on the mean luminance, the standard deviation luminance, the maximum luminance, and the minimum luminance of the image. The threshold setting unit sets a luminance threshold based on the calculated feature amount. The defect detecting unit detects, based on the set threshold, a defective pixel in the image obtained through imaging.
Patent Literature 2 discloses a defect detecting device that acquires a plurality of pieces of image information of a target workpiece captured from respectively different positions, successively selects a portion on this workpiece as a portion of interest, compares the feature amount of the luminance of an image portion corresponding to the portion of interest in each of the plurality of pieces of image information, and determines whether there is a defect in the workpiece based on the result of the comparison.
Patent Literature 1: Japanese Unexamined Patent Application Publication No. 2012-159376
Patent Literature 2: Japanese Unexamined Patent Application Publication No. 2013-195368
As described above, there has been a problem that an anomalous portion on a surface of a complex structure is hard to identify. Neither Patent Literature 1 nor Patent Literature 2 discloses this problem, that is, discusses identification of an anomalous portion on a surface of a complex structure.
The present disclosure is directed to providing a surface anomaly detecting device, a system, a method, and a non-transitory computer-readable medium that each solve the problem described above.
A surface anomaly detecting device according to the present disclosure includes:
dividing means configured to divide a structure into a plurality of clusters based on position information of a plurality of points on a surface of the structure;
coupling means configured to create a cluster group by coupling together two or more of the clusters;
determining means configured to determine a reflection luminance normal value of the cluster group based on a distribution of reflection luminance values at a plurality of points on a surface of the cluster group; and
identifying means configured to identify an anomalous portion on the surface of the cluster group based on a difference between the reflection luminance normal value and the reflection luminance value at each of the plurality of points on the surface of the cluster group.
A system according to the present disclosure includes:
a measuring device configured to acquire reflection luminance values at a plurality of points on a surface of a cluster group; and
a surface anomaly detecting device, wherein
the surface anomaly detecting device includes:
the surface anomaly detecting device is configured to identify the anomalous portion on the surface of the cluster group.
A method according to the present disclosure includes:
dividing a structure into a plurality of clusters based on position information of a plurality of points on a surface of the structure;
creating a cluster group by coupling together two or more of the clusters;
determining a reflection luminance normal value of the cluster group based on a distribution of reflection luminance values at a plurality of points on a surface of the cluster group; and
identifying an anomalous portion on the surface of the cluster group based on a difference between the reflection luminance normal value and the reflection luminance value at each of the plurality of points on the surface of the cluster group.
A non-transitory computer-readable medium according to the present disclosure stores a program that causes a computer to execute:
dividing a structure into a plurality of clusters based on position information of a plurality of points on a surface of the structure;
creating a cluster group by coupling together two or more of the clusters;
determining a reflection luminance normal value of the cluster group based on a distribution of reflection luminance values at a plurality of points on a surface of the cluster group; and
identifying an anomalous portion on the surface of the cluster group based on a difference between the reflection luminance normal value and the reflection luminance value at each of the plurality of points on the surface of the cluster group.
The present disclosure can provide a surface anomaly detecting device, a system, a method, and a non-transitory computer-readable medium that can identify an anomalous portion on a surface of a complex structure.
Hereinafter, some example embodiments of the present invention will be described with reference to the drawings. In the drawings, identical or corresponding elements are given identical reference characters, and duplicate descriptions thereof will be omitted, as necessary, for the sake of making the description clearer.
An overview of a surface anomaly detecting device and a system according to a first example embodiment will be given.
As illustrated in
The dividing means 111 divides a structure into a plurality of portions, that is, into a plurality of clusters based on position information of a plurality of points on a surface of the structure. For the position information, for example, position information in three-dimensional coordinates is used.
The coupling means 112 creates a cluster group by coupling together two or more of the divided clusters.
The determining means 113 determines a reflection luminance normal value of the created cluster group based on the distribution of reflection luminance values at a plurality of points on a surface of the cluster group.
The identifying means 114 identifies an anomalous portion on the surface of the cluster group based on a difference between the determined reflection luminance normal value and the reflection luminance value at each of the plurality of points on the surface of the cluster group.
As illustrated in
The reflection luminance measuring device 12 has a distance measuring function and a reflection luminance measuring function. The distance measuring function is a function of irradiating a structure, serving as a measurement target, with laser light and acquiring three-dimensional distance data to the structure.
Meanwhile, the reflection luminance measuring function is a function of measuring the reflection luminance of laser light reflected from a structure. By using the distance measuring function and the reflection luminance measuring function, the reflection luminance measuring device 12 acquires position information, in the three-dimensional coordinates, of a plurality of points on a surface of a structure and the reflection luminance value at each of the positions. In other words, the reflection luminance measuring device 12 acquires the reflection luminance values at a plurality of points on a surface of a cluster group. In this manner, the reflection luminance measuring device 12 acquires position information, in the three-dimensional coordinates, of a plurality of points on a surface of a structure and the reflection luminance values at these positions. The position information, in the three-dimensional coordinates, of a plurality of points on a surface of a structure having a three-dimensional structure and the reflection luminance values at these points are referred to collectively as three-dimensional point cloud data.
The surface anomaly detecting device 11 acquires, from the reflection luminance measuring device 12, position information, in the three-dimensional coordinates, of a plurality of points on a surface of a structure and the corresponding reflection luminance values. The surface anomaly detecting device 11 identifies an anomalous portion on a surface of a cluster group based on the acquired reflection luminance values.
The surface anomaly detecting device according to the first example embodiment will be described in detail.
In
In
As illustrated in
As illustrated in
As illustrated in
Meanwhile, the coupling means 112 of the surface anomaly detecting device 11 according to the first example embodiment couples the cluster C11a and the cluster C11b to create a cluster group Cg11. When creating the cluster group Cg11, the coupling means 112 couples the cluster C11a and the cluster C11b if the resulting cluster group Cg11 is included in the constituent element E11. In other words, the coupling means 112 couples the cluster C11a and the cluster C11b if the shape of the constituent element E11 includes the shape of the resulting cluster group Cg11.
Specifically, the coupling means 112 acquires, in advance, information regarding the shape and so on of each constituent element of a structure. For example, the coupling means 112 acquires, in advance, a design plan and so on of a structure. The coupling means 112 compares the shape of a cluster group resulting from coupling together two or more clusters against the shapes of the constituent elements of the structure. In other words, the coupling means 112 compares the shape of the cluster group Cg11 against the shape of the constituent element E11. The coupling means 112 confirms the coupling of the cluster C11a and the cluster C11b if the shape of the constituent element E11 includes the shape of the cluster group Cg11.
As a result, the surface anomaly detecting device 11 acquires a reflection luminance distribution of the cluster group Cg11 such as the one illustrated in
The determining means 113 determines, of the distribution of the reflection luminance values of the cluster group Cg11, the reflection luminance value with the highest frequency as the reflection luminance normal value, for example.
In addition, the determining means 113 identifies, of the distribution of the reflection luminance values of the cluster group Cg11, the cluster with the smallest dispersion as a minimum dispersion cluster. The determining means 113 may determine, of the distribution of the reflection luminance values of the identified minimum dispersion cluster, the reflection luminance value with the highest frequency as the reflection luminance normal value.
The identifying means 114 identifies, of a plurality of points on a surface of the cluster group Cg11, a predetermined point where the difference between its reflection luminance value and the reflection luminance normal value exceeds a threshold as an anomalous portion. For example, the reflection luminance of the section C illustrated in
The surface anomaly detecting device 11 according to the first example embodiment divides a structure into clusters and then creates a cluster group by coupling together two or more of the clusters. The surface anomaly detecting device 11 according to the first example embodiment further identifies an anomalous portion on a surface of the structure based on the distribution of reflection luminance values at a plurality of points on a surface of the created cluster group. With this configuration, as compared to a case where the distribution of reflection luminance values of a cluster is used, an anomalous portion can be identified more accurately particularly in a complex structure.
Consequently, with the surface anomaly detecting device 11 according to the first example embodiment, a surface anomaly detecting device and a system that can identify an anomalous portion on a surface of a complex structure can be provided. Moreover, with the surface anomaly detecting device 11, an anomalous portion, that is, a portion that needs repairing can be identified, and thus the repair can be made promptly.
Meanwhile, it is difficult to identify an anomalous portion accurately also when a structure is dissected (divided) finely into small clusters and when there is only a small number of points on the surface of each cluster. In such a case, the coupling means 112 may create a cluster group Cg11 by coupling a small cluster having no more than a predetermined number of points on its surface and an adjacent cluster adjacent to the small cluster.
An operation of the surface anomaly detecting device according to the first example embodiment will be described.
As illustrated in
The surface anomaly detecting device 11 divides the structure into clusters based on the position information of the three-dimensional point cloud data (step S102).
The surface anomaly detecting device 11 associates and couples clusters that belong to the same constituent element based on the position information of the three-dimensional point cloud data of the divided clusters (step S103). In the example of the structure illustrated in
The surface anomaly detecting device 11 determines a reflection luminance normal value of the cluster group based on the distribution of reflection luminance values at a plurality of points on a surface of the cluster group (step S104).
If the disparity of the reflection luminance value from the reflection luminance normal value in a point cloud exceeds a threshold (step S105: Yes), the surface anomaly detecting device 11 determines this point cloud as an anomalous portion of the structure (step S106). In other words, if the difference between the reflection luminance normal value and the reflection luminance value at a predetermined point, among a plurality of points on the surface of the cluster group, exceeds a threshold, the surface anomaly detecting device 11 determines this predetermined point as an anomalous portion of the structure.
If the disparity of the reflection luminance value from the reflection luminance normal value in the point cloud is no greater than the threshold (step S105: No), the surface anomaly detecting device 11 determines this point cloud as a normal portion of the structure (step S107). In other words, if the difference between the reflection luminance normal value and the reflection luminance value at a predetermined point, among a plurality of points on the surface of the cluster group, is no greater than the threshold, the surface anomaly detecting device 11 determines this predetermined point as a normal portion of the structure.
A surface anomaly detecting device 21 according to the second example embodiment differs from the surface anomaly detecting device 11 according to the first example embodiment in that the surface anomaly detecting device 21 corrects reflection luminance values in accordance with the angle of laser incidence at each point on a surface of a cluster group (a structure).
The angular dependence of the reflection luminance value with respect to reflected laser light changes in accordance with the properties of a surface of a structure. Therefore, when a structure has a curved surface, an anomalous portion in the surface of the structure can be identified with higher accuracy by correcting the reflection luminance value in accordance with the angle of laser incidence.
A point cloud PC21a illustrated in
As illustrated in
The surface anomaly detecting device 21 corrects the reflection luminance value at the range-finding point P21 based on the angle of laser incidence A21. For example, in the case of Lambert reflection, the relationship indicated in the expression (1) holds among a measured value L of the reflection luminance, the angle of laser incidence A21, and a correction value L1.
L1∝(L/cos (A21)) (1)
Therefore, the reflection luminance value at each point is corrected in accordance with the angle of laser incidence A21 based on the expression (1).
In correcting the reflection luminance value, a reflectance model based on Lambert reflection may be created, and the reflection luminance value may be corrected based on this reflectance model. Alternatively, the reflection luminance value may be corrected based on the characteristics of the reflectance measured in advance.
As illustrated in
S201 and step S202 will be described.
After step S103, the surface anomaly detecting device 21 estimates the angle of laser incidence A21 based on the direction of laser incidence at each point on the surface of the cluster group of the structure and the normal N21 at each point (step S201).
The surface anomaly detecting device 21 corrects the reflection luminance value at each point (each range-finding point) based on the estimated angle of laser incidence A21 (step S202). The reflection luminance value may be corrected based on the reflectance model that is based on Lambert reflection or based on the characteristics of the reflectance measured in advance.
After step S202, step S104 to step S107 are performed in a manner similar to that according to the first example embodiment.
In this example described above, step S201 and step S202 are performed between steps S103 and step S104, but this is not a limiting example. There is no limitation on the order of the processes as long as the condition that step S201 and step S202 be performed before step S104 is satisfied.
In this manner, as compared with the surface anomaly detecting device 11 according to the first example embodiment, the surface anomaly detecting device 21 according to the second example embodiment can identify an anomalous portion in a surface of particularly a curved structure with higher accuracy.
A point cloud PC31 illustrated in
A surface anomaly detecting device 31 according to the third example embodiment differs from the surface anomaly detecting device 11 according to the first example embodiment in that a point cloud within a cluster is further separated into point clouds each with the same angle of laser incidence and then an anomalous portion is identified. The point cloud PC31 will be described with an example of a cylindrical constituent element.
As illustrated in
The surface anomaly detecting device 31 determines a reflection luminance normal value of a subcluster group based on the distribution of reflection luminance values at a plurality of points on a surface of the subcluster group.
The surface anomaly detecting device 31 identifies an anomalous portion on a surface of a subcluster group based on a difference between the reflection luminance normal value of the subcluster group and the reflection luminance value at each of a plurality of points on the surface of the subcluster group. In this manner, the surface anomaly detecting device 31 identifies an anomalous portion on a surface of a subcluster group based on the reflection luminance value of each subcluster group.
An operation of the surface anomaly detecting device 31 according to the third example embodiment will be described.
As illustrated in
After step S201, the surface anomaly detecting device 31 further divides the cluster group into subcluster groups based on the angle of laser incidence (step S301). The surface anomaly detecting device 31 further divides the cluster group into subcluster groups per predetermined angular range of the angle of laser incidence.
The cluster group may be divided into subcluster groups per fixed range of the angle of laser incidence.
The surface anomaly detecting device 31 determines the reflection luminance normal value of a subcluster group based on the distribution of reflection luminance values at a plurality of points on a surface of the subcluster group (step S302). In other words, the surface anomaly detecting device 31 determines the normal value of the reflection luminance of a subcluster group that is a point cloud divided from a single cluster group and identified to have the same angle of laser incidence, based on the reflection luminance distribution of the subcluster group.
After step S302, step S105 to step S107 are performed in a manner similar to that according to the first example embodiment.
In this manner, the surface anomaly detecting device 31 identifies an anomalous portion on a surface of a subcluster group based on a difference between the reflection luminance normal value of the subcluster group and the reflection luminance value at each of a plurality of points on the surface of the subcluster group.
In this example described above, step S201 is performed between step S103 and step S301, but this is not a limiting example. There is no limitation on the order of the processes as long as the condition that step S201 be performed before step S301 is satisfied.
In this manner, as compared with the surface anomaly detecting device 11 according to the first example embodiment, the surface anomaly detecting device 31 according to the third example embodiment can identify an anomalous portion on a surface of particularly a curved structure with higher accuracy.
As illustrated in
The angle of laser incidence is estimated based on the direction of laser incidence at a range-finding point in a cluster group and the direction of the normal at the range-finding point in the cluster group. Therefore, an error in the normal leads to an error in the angle of laser incidence. Since the reflection luminance value at a range-finding point in a cluster group is corrected based on the angle of laser incidence, an accurate normal needs to be estimated in order to estimate the angle of laser incidence accurately.
Accordingly, as illustrated in
Specifically, the surface anomaly detecting device 41 further includes a complementing means (not illustrated). The complementing means calculates a plurality of complementary points that fill between the cluster C11a that is one cluster in a cluster group and the cluster C11b closest to the cluster C11a. The complementing means creates a complementary cluster C11c having a plurality of complementary points on its surface. In other words, the complementing means creates the complementary cluster C11c so as to connect the one end portion C11a1 and the one end portion C11b1. The surface anomaly detecting device 41 creates a complementary cluster group Cgc11 by coupling the cluster group Cg11 and the complementary cluster C11c.
At this point, the direction of the normal at a complementary point is estimated based on the directions of the normal at a plurality of range-finding points surrounding the complementary point. In other words, the normal is calculated and estimated from the positional relationship to the surrounding point cloud. The surface anomaly detecting device 41 identifies an anomalous portion of a structure by use of the complementary cluster group Cgc11 instead of the cluster group Cg11.
According to the fourth example embodiment, the added complementary points increase the number of surrounding points at the one end portion C11a1 of the cluster C11a. Thus, the normal at a range-finding point is estimated accurately, and in turn the angle of incidence is estimated accurately. The reflection luminance value at a range-finding point in a cluster group is corrected accurately based on the accurate angle of laser incidence.
Meanwhile, as illustrated in
The direction of the normal Nq11 at the complementary point Q11 may be estimated by averaging the directions of normal at a plurality of range-finding points surrounding the complementary point Q11. In a similar manner, the direction of the normal Nq12 at the complementary point Q12 may be estimated by averaging the directions of normal at a plurality of range-finding points surrounding the complementary point Q12.
As illustrated in
As illustrated in
After step S103, the surface anomaly detecting device 41 calculates a plurality of complementary points that fill between the cluster C11a and the cluster C11b closest to the cluster C11a (between the clusters) (step S401).
After step S401, step S201 to step S107 are performed in a manner similar to that according to the first example embodiment or the second example embodiment.
As illustrated in
As illustrated in
Step S401 is performed in a manner similar to that according to the fourth example embodiment.
After step S401, step S201 to step S107 are performed in a manner similar to that according to the first example embodiment or the third example embodiment.
In this manner, since the surface anomaly detecting device 41 according to the fourth example embodiment fills between clusters, as compared with the surface anomaly detecting devices according to the other example embodiments, the surface anomaly detecting device 41 can identify an anomalous portion on a surface of a structure with higher accuracy.
According to the foregoing example embodiments, the present invention has been described as a configuration of hardware, but the present invention is not limited thereto. According to the present invention, the processes of the constituent elements can also be implemented as a central processing unit (CPU) executes a computer program.
In the foregoing example embodiments, the program can be stored and provided to a computer by use of various types of non-transitory computer-readable media. The non-transitory computer-readable media include various types of tangible storage media. Examples of such non-transitory computer-readable media include a magnetic recording medium (specifically, a flexible disk, a magnetic tape, a hard-disk drive), a magneto-optical recording medium (specifically, a magneto-optical disk), a CD-ROM (read-only memory), a CD-R, a CD-R/W, and a semiconductor memory (specifically, a mask ROM, a programmable ROM (PROM), an erasable PROM (EPROM), a flash ROM, a random-access memory (RAM)). The program may also be supplied to a computer by use of various types of transitory computer-readable media. Examples of such transitory computer-readable media include an electric signal, an optical signal, and an electromagnetic wave. A transitory computer-readable medium can supply the program to a computer via a wired communication line, such as an electric wire or an optical fiber, or via a wireless communication line.
Thus far, the invention of the present application has been described with reference to some example embodiments, but the invention of the present application is not limited by the foregoing example embodiments. Various modifications that a person skilled in the art can appreciate can be made to the configurations and the details of the invention of the present application within the scope of the invention.
The present invention is not limited to the foregoing example embodiments, and modifications can be made, as appropriate, within the scope that does not depart from the spirit of the present invention.
A part or the whole of the foregoing example embodiments can also be expressed as in the following supplementary notes, which are not limiting.
A surface anomaly detecting device comprising:
dividing means configured to divide a structure into a plurality of clusters based on position information of a plurality of points on a surface of the structure;
coupling means configured to create a cluster group by coupling together two or more of the clusters;
determining means configured to determine a reflection luminance normal value of the cluster group based on a distribution of reflection luminance values at a plurality of points on a surface of the cluster group; and
identifying means configured to identify an anomalous portion on the surface of the cluster group based on a difference between the reflection luminance normal value and the reflection luminance value at each of the plurality of points on the surface of the cluster group.
The surface anomaly detecting device according to Supplementary note 1, wherein the identifying means is configured to identify, among the plurality of points on the surface of the cluster group, a predetermined point where the difference between the reflection luminance value and the reflection luminance normal value exceeds a threshold as the anomalous portion.
The surface anomaly detecting device according to Supplementary note 1 or 2, wherein the coupling means is configured to couple the clusters if the cluster group is included in a constituent element of the structure.
The surface anomaly detecting device according to Supplementary note 1 or 2, wherein the coupling means is configured to create the cluster group by coupling a small cluster having no more than a predetermined number of points on a surface thereof and an adjacent cluster adjacent to the small cluster.
The surface anomaly detecting device according to any one of Supplementary notes 1 to 4, wherein the determining means is configured to determine, of the distribution of the reflection luminance values of the cluster group, the reflection luminance value with a highest frequency as the reflection luminance normal value.
The surface anomaly detecting device according to any one of Supplementary notes 1 to 4, wherein the determining means is configured to
identify, of the distribution of the reflection luminance values of the cluster group, a minimum dispersion cluster with a smallest dispersion, and
determine, of the distribution of the reflection luminance values of the minimum dispersion cluster, the reflection luminance value with a highest frequency as the reflection luminance normal value.
The surface anomaly detecting device according to any one of Supplementary notes 1 to 6, wherein
an angle of laser incidence at a range-finding point that is one of the plurality of points on the surface of the cluster group is calculated based on a direction connecting the range-finding point of the cluster group with the surface anomaly detecting device and a direction of a normal at the range-finding point of the cluster group, and
the reflection luminance value at the range-finding point of the cluster group is corrected based on the angle of laser incidence.
The surface anomaly detecting device according to any one of Supplementary notes 1 to 7, wherein
an angle of laser incidence at a range-finding point that is one of the plurality of points on the surface of the cluster group is calculated based on a direction connecting the range-finding point of the cluster group with the surface anomaly detecting device and a direction of a normal at the range-finding point of the cluster group,
the dividing means is configured to further divide the cluster group into subcluster groups based on the angle of laser incidence,
the determining means is configured to determine a reflection luminance normal value of the subcluster group based on a distribution of reflection luminance values at a plurality of points on a surface of the subcluster group, and
the identifying means is configured to identify an anomalous portion on the surface of the subcluster group based on a difference between the reflection luminance normal value of the subcluster group and the reflection luminance value at each of the plurality of points on the surface of the subcluster group.
The surface anomaly detecting device according to Supplementary note 7 or 8, further comprising:
complementing means configured to calculate a plurality of complementary points that fill a space between a first cluster that is one of the clusters in the cluster group and a second cluster closest to the first cluster and create a complementary cluster having the plurality of complementary points on a surface thereof, wherein
the coupling means is configured to create a complementary cluster group by coupling the cluster group with the complementary cluster,
a direction of a normal at the complementary point is estimated based on directions of normal at a plurality of the range-finding points surrounding the complementary point, and
the anomalous portion of the structure is identified by use of the complementary cluster group instead of the cluster group.
The surface anomaly detecting device according to Supplementary note 9, wherein
a direction of a normal at a first range-finding point on one end portion of the first cluster facing the second cluster extends in the same direction as a direction of a normal at the complementary point closest to the first range-finding point, and
a direction of a normal at a second range-finding point on one end portion of the second cluster facing the first cluster extends in the same direction as a direction of a normal at the complementary point closest to the second range-finding point.
The surface anomaly detecting device according to Supplementary note 9 or 10, wherein the direction of the normal at the complementary point is estimated by averaging directions of normal at a plurality of the range-finding points surrounding the complementary point.
A system comprising:
a measuring device configured to acquire the reflection luminance values at a plurality of points on a surface of the cluster group; and
the surface anomaly detecting device according to any one of Supplementary notes 1 to 11,
wherein the surface anomaly detecting device is configured to identify the anomalous portion on the surface of the cluster group.
A method comprising:
dividing a structure into a plurality of clusters based on position information of a plurality of points on a surface of the structure;
creating a cluster group by coupling together two or more of the clusters;
determining a reflection luminance normal value of the cluster group based on a distribution of reflection luminance values at a plurality of points on a surface of the cluster group; and
identifying an anomalous portion on the surface of the cluster group based on a difference between the reflection luminance normal value and the reflection luminance value at each of the plurality of points on the surface of the cluster group.
A non-transitory computer-readable medium storing a program that causes a computer to execute:
dividing a structure into a plurality of clusters based on position information of a plurality of points on a surface of the structure;
creating a cluster group by coupling together two or more of the clusters;
determining a reflection luminance normal value of the cluster group based on a distribution of reflection luminance values at a plurality of points on a surface of the cluster group; and
identifying an anomalous portion on the surface of the cluster group based on a difference between the reflection luminance normal value and the reflection luminance value at each of the plurality of points on the surface of the cluster group.
10: system
11, 21, 31, 41: surface anomaly detecting device
111: dividing means
112: coupling means
113: determining means
114: identifying means
12: reflection luminance measuring device
E11, F11: constituent element
C11a, C11b: cluster
C11a1, C11b1: one end portion
C11c: complementary cluster
Cg11: cluster group
Cgc11: complementary cluster group
SCg31, SCg32: subcluster group
PC21, PC21a, PC31: point cloud
R21: three-dimensional region
P11, P12, P21: range-finding point
A21: angle of laser incidence
B21: direction of laser incidence
Np11, Nq11, N21: normal
L: measured value
L1: correction value
B, C, D: section
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2019/033294 | 8/26/2019 | WO |
