Wear measurement system using a computer model

Patent metadata

Field	Value
Publication number	US-9880075-B2
Application number	US-201615041523-A
Country	US
Kind code	B2
Filing date	Feb 11, 2016
Priority date	Feb 11, 2016
Publication date	Jan 30, 2018
Grant date	Jan 30, 2018

Abstract

A wear measurement system for a component is disclosed. The wear measurement system may include an imaging device configured to obtain a plurality of two-dimensional images of the component. The wear measurement system may also include a controller. The controller may be configured to generate a three-dimensional point cloud representing the component based on the two-dimensional images. The controller may also be configured to overlay a computer model of the component on the three-dimensional point cloud. Further, the controller may be configured to project the computer model on the two-dimensional images. The controller may also be configured to select at least two reference points appearing in each of a subset of images selected from the two-dimensional images. The controller may be configured to determine locations of the two reference points in the three-dimensional point cloud, determine an image distance between the locations, and determine an amount of wear based on the image distance.

First claim

What is claimed is:

1. A wear measurement system for a component, comprising:
an imaging device configured to obtain a plurality of two-dimensional images of the component; and
a controller configured to:
generate a three-dimensional point cloud representing the component based on the two-dimensional images;
overlay a computer model of the component on the three-dimensional point cloud;
project the computer model on the two-dimensional images;
select at least two reference points appearing in each image of a subset of images selected from the two-dimensional images;
determine locations of the at least two reference points in the three-dimensional point cloud;
determine an image distance between the locations; and
determine an amount of wear based on the image distance.

2. The wear measurement system of claim 1 , wherein the controller is further configured to:
select at least one feature appearing in each of the two-dimensional images;
determine positions and orientations of the imaging device for each of the two-dimensional images based on positions of the at least one feature in the two-dimensional images; and
generate the three-dimensional point cloud based on the positions and orientations of the imaging device and the positions of the at least one feature in the two-dimensional images.

3. The wear measurement system of claim 2 , wherein the controller is further configured to:
select a first set of register points associated with features in the computer model;
select a second set of register points in the two-dimensional images, the second set of register points corresponding to the features associated with the first set of register points;
determine register point locations corresponding to the second set in the three-dimensional point cloud; and
overlay the computer model on the three-dimensional point cloud by orienting the three-dimensional point cloud such that the first set of register points in the computer model overlap with the register point locations in the three-dimensional point cloud.

4. The wear measurement system of claim 3 , wherein the at least two reference points include:
a first reference point positioned on a projection of the computer model on each of the subset of images, and
a second reference point positioned on the component in each of the subset of images.

5. The wear measurement system of claim 4 , wherein the controller is configured to identify the locations of the first reference point and the second reference point by:
determining positions of the imaging device relative to the component for the subset of images;
projecting rays from the determined positions of the imaging device through the at least two reference points; and
determining the locations of the first reference point and the second reference point in the three-dimensional point cloud based on intersections of the rays.

6. The wear measurement system of claim 5 , wherein the controller is further configured to:
determine the image distance between the locations of the first reference point and the second reference point; and
convert the image distance into an actual distance based on a scaling factor.

7. The wear measurement system of claim 6 , wherein the scaling factor is based on a dimension determined from the computer model.

8. The wear measurement system of claim 7 , wherein the controller is configured to:
select a first image from the subset;
select a second image from the subset;
project a first ray originating at a first position of the imaging device, corresponding to the first image, the first ray passing through the first reference point in the first image;
project a second ray originating at a second position of the imaging device, corresponding to the second image, the second ray passing through the first reference point in the second image; and
determine a location of the first reference point in the three-dimensional point cloud based on an intersection of the first ray and the second ray.

9. The wear measurement system of claim 8 , wherein the controller is configured to determine the location in the three-dimensional point cloud at which a distance between the first ray and the second ray is less than a threshold distance.

10. The wear measurement system of claim 2 , wherein the controller is configured to automatically select the at least one feature by comparing the two-dimensional images with an image of the at least one feature stored in a memory associated with the controller.

11. The wear measurement system of claim 2 , further including an input device configured to receive inputs from an operator, wherein the controller is configured to select the at least one feature based on the inputs received from the operator.

12. A method of measuring wear on a component, comprising:
obtaining, using an imaging device, a plurality of two-dimensional images of the component;
generating, using a controller, a three-dimensional point cloud of the component based on the two-dimensional images;
overlaying a computer model of the component on the three-dimensional point cloud;
projecting the computer model on the two-dimensional images;
selecting at least two reference points appearing in each image of a subset of images selected from the two-dimensional images;
determining locations of the at least two reference points in the three-dimensional point cloud;
determining an image distance between the locations; and
determining an amount of wear based on the image distance.

13. The method of claim 12 , wherein generating the three-dimensional point cloud includes:
selecting at least one feature that appears in each of the two-dimensional images;
determining positions and orientations of the imaging device for each of the two-dimensional images based on positions of the at least one feature in the two-dimensional images; and
generating the three-dimensional point cloud based on the positions and orientations of the imaging device and the positions of the at least one feature in the two-dimensional images.

14. The method of claim 13 , wherein selecting the at least two reference points includes:
selecting a first reference point positioned on a projection of the computer model on each of the subset of images, and
selecting a second reference point positioned on the component in each of the subset of images.

15. The method of claim 14 , wherein determining the locations of the two reference points includes:
selecting a first image from the subset;
selecting a second image from the subset;
projecting a first ray originating at a first position of the imaging device, corresponding to the first image, the first ray passing through the first reference point in the first image;
projecting a second ray originating at a second position of the imaging device, corresponding to the second image, the second ray passing through the first reference point in the second image;
projecting a third ray originating at the first position of the imaging device, the third ray passing through the second reference point in the first image;
projecting a fourth ray originating at the second position of the imaging device, the fourth ray passing through the second reference point in the second image;
determining a first location of the first reference point in the three-dimensional point cloud based on a first intersection of the first ray and the second ray; and
determining a second location of the second reference point in the three-dimensional point cloud based on a second intersection of the third ray and the fourth ray.

16. The method of

Assignees

• Caterpillar Inc

Inventors

• Finch Nolan S
• Wang Yue
• HAN Kook In
• Bennett Timothy J
• Smyth Daniel A

Classifications

• B60C11/24

  Wear-indicating arrangements · CPC title

• G01N21/8851

  Scan or image signal processing specially adapted therefor, e.g. for scan signal adjustment, for detecting different kinds of defects, for compensating for structures, markings, edges (G01N21/8806 and G01N21/93 - G01N21/95692 take precedence; optical measurement of dimensions G01B11/00; optical scanning G02B26/10; image transformation G06T3/00; computerised image enhancement G06T5/00; image processing per se for flaw detection G06T7/0002) · CPC title

• G01M17/03 Primary

  Endless-tracks · CPC title

• G06F30/00

  Computer-aided design [CAD] · CPC title

• B60C11/246

  Tread wear monitoring systems · CPC title