SYSTEM AND METHOD OF ANALYZING A CURVED SURFACE

• US 20170146462A1
• Filed: 11/23/2015
• Published: 05/25/2017
• Est. Priority Date: 11/23/2015
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Baker, Anthony W., Bellavia, Christopher
• Granted Patent: US 10,451,407 B2
• Time in Patent Office: Days
• CPC Class Codes: G01B 11/14 for measuring distance or clearance between spaced objects or spaced apertures G01B11/26 takes precedence; rangefinders G01C3/00
• CPC Class Codes: G01B 11/24 for measuring contours or curvatures
• CPC Class Codes: G01N 2021/8883 involving the calculation of gauges, generating models
• CPC Class Codes: G01N 21/8851 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 Class Codes: G01N 21/9515 Objects of complex shape, e.g. examined with use of a surface follower device measuring contours and curvatures G01B11/24
• CPC Class Codes: G01N 2201/10 Scanning
• CPC Class Codes: G01N 2201/12 Circuits of general importance; Signal processing
• CPC Class Codes: G06T 2207/10028 Range image; Depth image; 3D point clouds
• CPC Class Codes: G06T 2207/20056 Discrete and fast Fourier transform, [DFT, FFT]
• CPC Class Codes: G06T 7/001 using an image reference approach

Abstract

A method of analyzing a curved surface is provided. The method includes obtaining a first data point set including data points representative of a distance between points along the curved surface and a reference axis, determining outlier data points in the first data point set, extracting the outlier data points from the first data point set, thereby defining a second data point set. The method also includes determining a fitted curve for the second data point set, wherein the fitted curve defines an approximate true curve of the curved surface.

Claims

1. A method of analyzing a curved surface, said method comprising:

obtaining a first data point set comprising data points representative of a distance between points along the curved surface and a reference axis;

determining outlier data points in the first data point set;

extracting the outlier data points from the first data point set, thereby defining a second data point set; and

determining a fitted curve for the second data point set, wherein the fitted curve defines an approximate true curve of the curved surface.

2. The method in accordance with claim 1 further comprising comparing the fitted curve to the data points of the first data point set to determine anomalies in the curved surface.

3. The method in accordance with claim 1, wherein determining a fitted curve comprises:

determining a plurality of Fourier transforms for data points in the second data point set; and

plotting the fitted curve based on the plurality of Fourier transforms.

4. The method in accordance with claim 1, wherein determining a fitted curve comprises:

determining a third or higher degree polynomial representation for data points in the second data point set; and

plotting the fitted curve based on the polynomial representation.

5. The method in accordance with claim 1, wherein determining outlier data points comprises:

determining an initial fitted curve for the first data point set; and

determining residuals for data points in the first data point set relative to the initial fitted curve.

6. The method in accordance with claim 5, wherein extracting the outlier data points comprises:

determining a standard deviation for the residuals; and

defining the outlier data points based on the standard deviation for the residuals.

7. The method in accordance with claim 1, wherein obtaining a first data point set comprises obtaining the first data point set comprising a three-dimensional point cloud representative of a distance between points along the curved surface and a reference plane.

8. The method in accordance with claim 1, wherein obtaining a first data point set comprises defining the reference axis as an axis in a standard coordinate system such that a variable vertical displacement is defined between data points in the first data point set and the reference axis.

9. A system for use in analyzing a curved surface, said system comprising:

a scanning device that obtains a first data point set including data points representative of a distance between points along the curved surface and a reference axis; and

a computing device coupled in communication with said scanning device, wherein said computing device;

determines outlier data points in the first data point set;

extracts the outlier data points from the first data point set, thereby defining a second data point set; and

determines a fitted curve for the second data point set, wherein the fitted curve defines an approximate true curve of the curved surface.

10. The system in accordance with claim 9, wherein said scanning device obtains the first data point set including a three-dimensional point cloud representative of a distance between points along the curved surface and a reference plane.

11. The system in accordance with claim 9, wherein said computing device further compares the fitted curve to the data points of the first data point set to determine anomalies in the curved surface.

12. The system in accordance with claim 9, wherein said computing device further:

determines a plurality of Fourier transforms for data points in the second data point set; and

plots the fitted curve based on the plurality of Fourier transforms.

13. The system in accordance with claim 9, wherein said computing device further:

determines an initial fitted curve for the first data point set; and

determines residuals for data points in the first data point set relative to the initial fitted curve.

14. The system in accordance with claim 13, wherein said computing device further:

determines a standard deviation for the residuals; and

defines the outlier data points based on the standard deviation for the residuals.

15. The system in accordance with claim 9, wherein said computing device further defines the reference axis as an axis in a standard coordinate system such that a variable vertical displacement is defined between data points in the first data point set and the reference axis.

16. A non-transitory computer-readable media having computer-executable instructions embodied thereon for use in analyzing a curved surface, wherein, when executed by a computing device, the computer-executable instructions cause the computing device to:

determine outlier data points in a first data point set, wherein the first data point set includes data points representative of a distance between points along the curved surface and a reference axis;

extract the outlier data points from the first data point set, thereby defining a second data point set; and

determine a fitted curve for the second data point set, wherein the fitted curve defines an approximate true curve of the curved surface.

17. The non-transitory computer readable storage device in accordance with claim 16 further comprising computer-executable instructions that cause the computing device to compare the true curve to the data points of the first data point set to determine anomalies in the curved surface.

18. The non-transitory computer readable storage device in accordance with claim 16 further comprising computer-executable instructions that cause the computing device to:

determine a plurality of Fourier transforms for data points in the second data point set; and

plot the fitted curve based on the plurality of Fourier transforms.

19. The non-transitory computer readable storage device in accordance with claim 16 further comprising computer-executable instructions that cause the computing device to:

determine an initial fitted curve for the first data point set; and

determine residuals for data points in the first data point set relative to the initial fitted curve.

20. The non-transitory computer readable storage device in accordance with claim 16 further comprising computer-executable instructions that cause the computing device to:

determine a standard deviation for the residuals; and

define the outlier data points based on the standard deviation for the residuals.