Surface abnormality detection device and system

Patent metadata

Field	Value
Publication number	US-2022170739-A1
Application number	US-201917599747-A
Country	US
Kind code	A1
Filing date	Apr 3, 2019
Priority date	Apr 3, 2019
Publication date	Jun 2, 2022
Grant date	—

Abstract

There is provided a surface abnormality detection device, and a system, capable of detecting an abnormal portion having a displacement below the distance measurement accuracy when detecting the abnormal portion on the surface of a structure. A surface abnormality detection device includes a classification means for classifying an object under measurement into one or more clusters having the same structure, based on position information at a plurality of points on a surface of the object under measurement; a determination means for determining a reflection brightness normal value of the cluster based on a distribution of reflection brightness values at a plurality of points on a surface of the cluster; and an identification means for identifying an abnormal portion on the surface of the cluster based on a difference between the reflection brightness normal value and the reflection brightness value at each of the plurality of points.

First claim

What is claimed is:

1 . A surface abnormality detection device, comprising:
at least one memory storing instructions, and at least one processor configured to execute the instructions to; classify an object under measurement into one or more clusters having the same structure, based on position information at a plurality of points on a surface of the object under measurement; determine a reflection brightness normal value of the cluster based on a distribution of reflection brightness values at a plurality of points on a surface of the cluster; and identify an abnormal portion on the surface of the cluster based on a difference between the reflection brightness normal value and the reflection brightness value at each of the plurality of points on the surface of the cluster.

2 . The surface abnormality detection device according to claim 1 , wherein
the reflection brightness value is corrected based on an attenuation amount due to a distance between an own device which is an observation point and the point on the surface of the cluster.

3 . The surface abnormality detection device according to claim 1 , wherein
a laser incident angle at a distance measurement point of the cluster is calculated based on a direction connecting the distance measurement point of the cluster and the own device, and a perpendicular line at the distance measurement point of the cluster, and the reflection brightness value at the distance measurement point of the cluster is further corrected based on the laser incident angle.

4 . The surface abnormality detection device according to claim 3 , wherein
the at least one processor further configured to execute the instructions to; classify the cluster into subclusters based on the laser incident angle, determine a reflection brightness normal value of the subcluster based on a distribution of reflection brightness values at a plurality of points on a surface of the subcluster, and identify an abnormal portion on the surface of the subcluster based on a difference between the reflection brightness normal value of the subcluster and the reflection brightness value at each of the plurality of points on the surface of the subcluster.

5 . The surface abnormality detection device according to claim 1 , wherein
the at least one processor further configured to execute the instructions to; determine an RGB normal value of the cluster based on a distribution of RGB values at the plurality of points on the surface of the cluster, identify an abnormal portion on the surface of the cluster based on a difference between the RGB normal value and the RGB value at each of the plurality of points on the surface of the cluster, and identify a desired abnormal portion based on the abnormal portion identified using the reflection brightness value and the abnormal portion identified using the RGB value.

6 . The surface abnormality detection device according to claim 1 , wherein
a roughness value at each of the plurality of points on the surface of the cluster is calculated based on the position information at the plurality of points on the surface of the cluster, the at least one processor further configured to execute the instructions to; determine a roughness normal value of the cluster based on a distribution of the roughness values at the plurality of points on the surface of the cluster, identify an abnormal portion on the surface of the cluster based on a difference between the roughness normal value and the roughness value at each of the plurality of points on the surface of the cluster, and identify a desired abnormal portion based on the abnormal portion identified using the reflection brightness value and the abnormal portion identified using the roughness value.

7 . A surface abnormality detection device, comprising:
at least one memory storing instructions, and at least one processor configured to execute the instructions to; calculate a first incident angle of a laser for each of a plurality of distance measurement points based on position information of a first observation point, and position information, included in first point cloud data, of the plurality of distance measurement points of a surface of an object under measurement; calculate a second incident angle of a laser for each of the plurality of distance measurement points based on position information of a second observation point, and position information of the plurality of distance measurement points included in second point cloud data; make an adjustment to match positions for each of the plurality of distance measurement points based on the position information of the plurality of distance measurement points in the first point cloud data and the position information of the plurality of distance measurement points in the second point cloud data; calculate, for each of the plurality of distance measurement points, a reflection brightness difference value which is a difference between a first reflection brightness value at each of the plurality of distance measurement points in the first point cloud data after the position adjustment and a second reflection brightness value at each of the plurality of distance measurement points in the second point cloud data after the position adjustment; calculate, for each of the plurality of distance measurement points, an incident angle difference which is a difference between the first incident angle at each of the plurality of distance measurement points in the first point cloud data after the position adjustment and the second incident angle at each of the plurality of distance measurement points in the second point cloud data after the position adjustment, and correcting, for each of the plurality of distance measurement points, the reflection brightness difference value based on the incident angle difference; and identify an abnormal portion of the object under measurement based on the reflection brightness difference value after the correction.

8 . A surface abnormality detection device, comprising:
at least one memory storing instructions, and at least one processor configured to execute the instructions to; make an adjustment to match positions for each of a plurality of distance measurement points based on position information of the plurality of distance measurement points on a surface of an object under measurement, the position information being included in cloud data for evaluation and position information of the plurality of distance measurement points included in cloud data for comparison; calculate, for each of the plurality of distance measurement points, a reflection brightness difference value which is a difference between a reflection brightness value for evaluation at each of the plurality of distance measurement points in the cloud data for evaluation after the position adjustment and a reflection brightness value for comparison at each of the plurality of distance measurement points in the cloud data for comparison after the position adjustment; and identify an abnormal portion of the object under measurement based on the reflection brightness difference value.

9 . (canceled)

10 . A system, comprising:
a measurement device configured to acquire the reflection brightness value at each of a plurality of points on a surface of an object under measurement; and the surface abnormality detection device according to claim 1 , wherein the surface abnormality detection device
identifies an abnormal portion on the surface of the object under measurement.

Assignees

• Nec Corp

Inventors

• Ono Yoshimasa
• Tsuji Akira
• Noguchi Hidemi
• Abe Junichi

Classifications

• G06T7/0002

  Inspection of images, e.g. flaw detection · CPC title

• G01S7/4802

  using analysis of echo signal for target characterisation; Target signature; Target cross-section · CPC title

• G06T2207/10028

  Range image; Depth image; 3D point clouds · CPC title

• G01S17/89

  for mapping or imaging · CPC title

• G01N21/9515

  Objects of complex shape, e.g. examined with use of a surface follower device (measuring contours and curvatures G01B11/24) · CPC title