Method and device for determining orientations or fiber elements in a part made of composite material

1. A method of determining orientations of fiber elements assembled in a part made of composite material, said fiber elements having an initial shape that is characterized by a length, a width, and a thickness, said method comprising:

obtaining an image of the part, each pixel of the image representing material density at a point of the part represented in the image by that pixel;

extracting from the image, for each of a plurality of fiber elements of the part, a line that is representative of the fiber element along its length in the part;

for each line extracted from the image:

extending the line in width at a plurality of reference points of said line, in compliance with the width of the fiber element of which the line is representative, said extension resulting, for each reference point, in a plurality of extended points associated with that reference point; and

associating an orientation with each extended point associated with a reference point, which orientation is parallel to the direction of the line at that reference point;

evaluating, for a plurality of extended points, a mean orientation of the plurality of fiber elements at said plurality of extended points from the orientations associated with the extended points; and

determining, for each of the evaluated mean orientations, a proportion of fiber elements having said mean orientation.

2. The method according to claim 1 , wherein the image of the part is a three-dimensional image and said extending further comprises extending the line at said plurality of reference points in thickness in compliance with the thickness of the fiber element of which the line is representative.

3. The method according to claim 1 , wherein:

some or all of the fiber elements assembled in the part carry markers along the length of the fiber elements;

said extracting comprises thresholding the image using a threshold defined on the basis of the density of the material of said markers, said thresholding resulting in an image that represents said markers; and

the lines are extracted from the markers represented in the image that results from the thresholding.

4. The method according to claim 1 , wherein said extracting comprises determining boundaries for each fiber element of the part, the lines representative of the fiber elements being extracted from the determined boundaries.

5. The method according to claim 1 , wherein at least said extending and said associating are performed by using a moving box defining a sub-volume of predefined dimensions that is moved over all or part of the part.

6. The method according to claim 1 , wherein the orientations of the fiber elements and the proportions of fiber elements having those mean orientations are stored in an orientation tensor.

7. The method according to claim 1 , wherein the image of the part is a tomographic image.

8. A non-destructive inspection method applied to a composite material part, said composite material comprising an assembly of fiber elements, said inspection method comprising:

using a digital imaging system to acquire an image of the part, each pixel of the image representing material density at a point of the part represented in the image by that pixel;

determining the orientations of the fiber elements of the part by performing a determination method according to claim 1 ; and

performing a non-destructive inspection on the part using the determined orientations.

9. The non-destructive inspection method according to claim 8 , wherein the part is an aviation part.

10. A determination device for determining the orientations of fiber elements assembled in a part made of composite material, said fiber elements having an initial shape that is characterized by a length, a width, and a thickness, said device comprising:

an obtaining module suitable for obtaining an image of the part, each pixel of the image representing material density at a point of the part represented in the image by that pixel;

an extraction module configured to extract from the image, for at least one fiber element of the part, a line that is representative of that fiber element over all or part of its length in the part;

an extension module configured to extend each line extracted from the image in width at a plurality of reference points of said line, in compliance with the width of the fiber element of which the line is representative, said extension resulting for each reference point in a plurality of extended points associated with that reference point;

an association module configured to associate an orientation with each extended point associated with a reference point of a line extracted from the image, which orientation is parallel to the direction of the line at that reference point;

an evaluation module configured to evaluate, for a plurality of extended points, a mean orientation of the plurality of fiber elements at said plurality of extended points from the orientations associated with the extended points; and

a determination module configured to determine, for each of the evaluated mean orientations, a proportion of fiber elements having said mean orientation.

11. A non-destructive inspection system for use in inspecting a composite material part, said composite material part comprising an assembly of fiber elements, said inspection system comprising:

a digital imaging system configured to acquire an image of the part, each pixel of the image representing material density at a point of the part represented in the image by that pixel;

a determination device for determining the orientations of fiber elements of the part in accordance with claim 10 ; and

an inspection device for inspecting the part and configured to use the orientations as determined in this way.