METHOD FOR THE PRE-PROCESSING OF A THREE-DIMENSIONAL IMAGE OF THE SURFACE OF A TYRE FOR USE IN THE INSPECTION OF SAID SURFACE
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Accused Products
Abstract
A method for inspecting a portion of a tyre surface involves comparison with an image of a three-dimensional (“3D”) reference surface. The method includes: extracting contours of graphic elements of an image of a 3D profile of a surface to be inspected; transforming the reference surface by establishing a correspondence between the contours of the graphic elements of the surface to be inspected and contours of identical graphic elements of the reference surface using a series of transformations; associating a B-spline surface, which includes control points, with the graphic elements of the transformed reference surface; and deforming the contours of the graphic elements of the reference surface by modifying positions of the control points of the B-spline surface so as to minimize distances between the contours of the graphic elements of the reference surface and the contours of the graphic elements of the surface to be inspected corresponding thereto.
19 Citations
26 Claims
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1-13. -13. (canceled)
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14. A method for inspecting a portion of a surface of a tyre by comparison with an image of a three-dimensional reference surface, the reference surface and the surface of the tyre including markings in relief, the method comprising steps of:
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obtaining an image of a three-dimensional profile of a tyre surface to be inspected; extracting, from the image of the three-dimensional profile of the tyre surface to be inspected, contours of graphic elements of the tyre surface to be inspected; transforming the image of the reference surface using a first series of transformations to establish a correspondence between the contours of the graphic elements of the tyre surface to be inspected and contours of graphic elements of the reference surface; after the transforming step, associating an elementary B-spline surface, which includes a first set of control points, with each graphic element of the transformed image of the reference surface; and
,for each graphic element of the reference surface, carrying out a first deformation of the contour of the graphic element of the reference surface by modifying positions of corresponding control points of the first set of control points of the elementary B-spline surface so as to minimize a distance between the contour of the graphic element of the reference surface and a corresponding contour of a graphic element of the tyre surface to be inspected. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. An inspection apparatus for inspecting a surface of a tyre, the apparatus comprising:
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a memory storing digital data describing a reference surface of a tyre; a processor programmed to calculate algorithms of a program of a tyre inspection method, including; extracting, from an image of a three-dimensional profile of a tyre surface to be inspected, contours of graphic elements of the tyre surface to be inspected, transforming an image of the reference surface using a first series of transformations to establish a correspondence between the contours of the graphic elements of the tyre surface to be inspected and contours of graphic elements of the reference surface, after the transforming, associating an elementary B-spline surface, which includes a first set of control points, with each graphic element of the transformed image of the reference surface, and, for each graphic element of the reference surface, carrying out a first deformation of the contour of the graphic element of the reference surface by modifying positions of corresponding control points of the first set of control points of the elementary B-spline surface so as to minimize a distance between the contour of the graphic element of the reference surface and a corresponding contour of a graphic element of the tyre surface to be inspected.
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Specification