Multi-scale method for measuring the shape, movement and/or deformation of a structural part subjected to stresses by creating a plurality of colorimetric speckled patterns

Patent metadata

Field	Value
Publication number	US-2016155240-A1
Application number	US-201414905597-A
Country	US
Kind code	A1
Filing date	Jul 9, 2014
Priority date	Jul 15, 2013
Publication date	Jun 2, 2016
Grant date	—

Abstract

Disclosed is a method for measuring movement and/or deformation of a study part subjected to an external stress, the method implementing a color digital image acquisition device and image correlation unit. The method includes: acquisition ( 250 ) of a plurality of color digital images of the surface of the study part by way of the color digital image acquisition device during the application of an external stress on the study part, and processing ( 260 ) of the color digital images acquired in the step of acquisition of a plurality of color digital images so as to highlight contrasting details on variable scales.

First claim

1 . A method for measuring movement and/or deformation of a study part ( 150 ) subjected to an external stress, said method implementing a color digital image acquisition device ( 110 ) and image correlation means, comprising the following steps:
acquisition ( 250 ) of a plurality of color digital images ( 500 ) of the surface of the study part ( 150 ) by means of the color digital image acquisition device ( 110 ) during the application of an external stress on said study part ( 150 ), processing ( 260 ) of the color digital images ( 500 ) acquired in the step of acquisition ( 250 ) of a plurality of color digital images ( 500 ) so as to highlight contrasting details on variable scales, and correlation ( 270 , 280 ) of all of the processed digital images ( 260 ) to determine the fields of movement on the scales associated with each processing operation ( 260 ).

2 . The method according to claim 1 , further comprising the following step:
creation ( 210 , 220 ) of at least two speckled patterns on the surface of said study part ( 150 ), the first speckled pattern ( 300 ) comprising a first color and the second speckled pattern ( 400 ) having a second color different from the first color.

3 . The method according to in claim 1 , wherein the surface of the study part ( 150 ) comprises a texture naturally having a first speckled pattern ( 300 ) comprising a first color and a second speckled pattern ( 400 ) comprising a second color different from the first color.

4 . The method according to claim 2 , wherein the first speckled pattern ( 300 ) comprises a first correlation length and the second speckled pattern ( 400 ) comprises a second correlation length different from the first correlation length.

5 . The method according to claim 4 , wherein the second correlation length is less than the first correlation length.

6 . The method according to claim 2 , wherein the step of processing ( 260 ) of the color digital images ( 500 ) comprises:
a substep ( 261 ) of first colorimetric filtering of the color digital images ( 500 ) in order to obtain a first series of filtered digital images ( 600 ) comprising only the first speckled pattern ( 300 ); a substep ( 262 ) of second colorimetric filtering of the color digital images ( 500 ) in order to obtain a second series of filtered digital images ( 700 ) comprising only the second speckled pattern ( 400 ).

7 . The method according to claim 2 , wherein the step of processing ( 260 ) of the color digital images ( 500 ) comprises:
a substep ( 261 ) of first colorimetric filtering of the color digital images ( 500 ) in order to obtain a first series of filtered digital images ( 600 ) comprising only the first speckled pattern ( 300 ); a substep ( 262 ) of second colorimetric filtering of the color digital images ( 500 ) in order to obtain a second series of filtered digital images ( 700 ) comprising the first speckled pattern ( 300 ) and the second speckled pattern ( 400 ).

8 . The method according to claim 6 , further comprising a step ( 270 ) of determination of a first field of movement and/or of a first field of deformation from the first series of filtered digital images ( 600 ).

9 . The method according to claim 7 , further comprising a step ( 280 ) of determination of a second field of movement and/or of a second field of deformation from the second series of filtered digital images ( 700 ).

10 . The method according to claim 8 , wherein the step ( 280 ) of determination of a second field of movement and/or of a second field of deformation is initialized by the first field of movement and/or the first field of deformation.

11 . A system for measuring movement and/or deformation of a study part ( 150 ) subjected to an external stress, said system comprising means for:
acquiring ( 250 ) a plurality of color digital images ( 500 ) of the surface of the study part ( 150 ) by means of the color digital image acquisition device ( 110 ) during the application of an external stress on said study part ( 150 ), processing ( 260 ) color digital images ( 500 ) acquired in the step of acquisition ( 250 ) of a plurality of color digital images ( 500 ) so as to highlight contrasting details on variable scales, and correlating ( 270 , 280 ) all of the processed digital images ( 260 ) to determine the fields of movement on the scales associated with each processing operation ( 260 ).

12 . The method according to claim 3 , wherein the first speckled pattern ( 300 ) comprises a first correlation length and the second speckled pattern ( 400 ) comprises a second correlation length different from the first correlation length.

13 . The method according to claim 3 , wherein the step of processing ( 260 ) of the color digital images ( 500 ) comprises:
a substep ( 261 ) of first colorimetric filtering of the color digital images ( 500 ) in order to obtain a first series of filtered digital images ( 600 ) comprising only the first speckled pattern ( 300 ); a substep ( 262 ) of second colorimetric filtering of the color digital images ( 500 ) in order to obtain a second series of filtered digital images ( 700 ) comprising only the second speckled pattern ( 400 ).

14 . The method according to claim 4 , wherein the step of processing ( 260 ) of the color digital images ( 500 ) comprises:
a substep ( 261 ) of first colorimetric filtering of the color digital images ( 500 ) in order to obtain a first series of filtered digital images ( 600 ) comprising only the first speckled pattern ( 300 ); a substep ( 262 ) of second colorimetric filtering of the color digital images ( 500 ) in order to obtain a second series of filtered digital images ( 700 ) comprising only the second speckled pattern ( 400 ).

15 . The method according to claim 5 , wherein the step of processing ( 260 ) of the color digital images ( 500 ) comprises:
a substep ( 261 ) of first colorimetric filtering of the color digital images ( 500 ) in order to obtain a first series of filtered digital images ( 600 ) comprising only the first speckled pattern ( 300 ); a substep ( 262 ) of second colorimetric filtering of the color digital images ( 500 ) in order to obtain a second series of filtered digital images ( 700 ) comprising only the second speckled pattern ( 400 ).

16 . The method according to claim 3 , wherein the step of processing ( 260 ) of the color digital images ( 500 ) comprises:
a substep ( 261 ) of first colorimetric filtering of the color digital images ( 500 ) in order to obtain a first series of filtered digital images ( 600 ) comprising only the first speckled pattern ( 300 ); a substep ( 262 ) of second colorimetric filtering of the color digital images ( 500 ) in order to obtain a second series of filtered digital images ( 700 ) comprising the first speckled pattern ( 300 ) and the second speckled pattern ( 400 ).

17 . The method according to claim 4 , wherein the step of processing ( 260 ) of the color digital images ( 500 ) comprises:
a substep ( 261 ) of first colorimetric filtering of the color digital images ( 500 ) in order to obtain a first series of filtered digital images ( 600 ) comprising only the first speckled pattern ( 300 ); a substep ( 262 ) of second colorimetric filtering of the color digital images ( 500 ) in order to obtain a second series of filtered digital images ( 700 ) comprising the first speckled pattern ( 300 ) and the second speckled pattern ( 400 ).

18 . The method according to claim 5 , wherein the step of processing ( 260 ) of the color digital images ( 500 ) comprises:
a substep ( 261 ) of f

Assignees

• Eads Europ Aeronautic Defence
• Centre Nat Rech Scient
• Ecole Normale Supérieure De Cachan

Inventors

• Petiot Caroline
• Roux Stephane
• Hild Francois

Classifications

• G06T7/204 Primary

  Physics · mapped topic

• G06T2207/10024

  Color image · CPC title

• G06T7/408

  Physics · mapped topic

• G06T7/0026

  Physics · mapped topic

• G06T2207/30164

  Workpiece; Machine component · CPC title