Method for Processing a Three-Dimensional Image of the Surface of a Tire so That It Can be Used to Inspect the Said Surface
First Claim
1. A method for inspecting a portion of the surface of a tire, said surface comprising markings in relief, wherein the method comprises the steps of:
- determining the three-dimensional profile of the surface to be inspected;
locating characteristic points on the surface to be inspected and matching these points with corresponding characteristic points originating from three-dimensional data of a reference surface, so as to create a set of pairs of matched characteristic points;
in an iterative manner, a first transformation function is sought, applied to the characteristic points of the reference surface, so that the value representing the sum of the distances between each of the characteristic points of the reference surface, transformed with the aid of said first transformation function, and the points of the surface to be inspected that are matched with them, is minimal; and
applying said first transformation function to all of the points of the reference surface in order to obtain a transformed reference surface,wherein the transformation function is an affine function comprising a homothetic transformation the ratio of which has an absolute value that is different from 1.
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Accused Products
Abstract
Method for inspecting a zone of the surface of a tire, said surface comprising markings in relief, wherein the three-dimensional profile of the surface to be inspected is determined, characteristic points on the surface to be inspected are located and these points are matched with the corresponding points originating from the three-dimensional data of a reference surface, so as to create a set of pairs of matched points, in an iterative manner, a first affine transformation function is sought, applied to the characteristic points of the reference surface, so that the value representing the sum of the distances between each of the characteristic points of the reference surface, which points are transformed with the aid of said first transformation function, and the points of the surface to be inspected that are matched with them, is minimal, and said first transformation function is applied to all of the points of the reference surface in order to obtain a transformed reference surface.
33 Citations
13 Claims
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1. A method for inspecting a portion of the surface of a tire, said surface comprising markings in relief, wherein the method comprises the steps of:
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determining the three-dimensional profile of the surface to be inspected; locating characteristic points on the surface to be inspected and matching these points with corresponding characteristic points originating from three-dimensional data of a reference surface, so as to create a set of pairs of matched characteristic points; in an iterative manner, a first transformation function is sought, applied to the characteristic points of the reference surface, so that the value representing the sum of the distances between each of the characteristic points of the reference surface, transformed with the aid of said first transformation function, and the points of the surface to be inspected that are matched with them, is minimal; and applying said first transformation function to all of the points of the reference surface in order to obtain a transformed reference surface, wherein the transformation function is an affine function comprising a homothetic transformation the ratio of which has an absolute value that is different from 1. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A device for inspecting the surface of a tire comprising means for making it possible to determine the three-dimensional profile of the surface to be inspected, means for storing the digital data describing the reference surface, and computerized calculation means capable of applying the calculation algorithms comprising the steps in which:
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the three-dimensional profile of the surface to be inspected is determined, the characteristic points are located on the surface to be inspected, and these points are matched with the corresponding points originating from the three-dimensional data of a reference surface so as to create a set of pairs of matched points, in an iterative manner, a first affine transformation function is sought comprising a homothetic transformation the ratio of which has an absolute value different from 1, applied to the characteristic points of the reference surface, so that the value representing the sum of the distances between each of the characteristic points of the reference surface, which points are transformed with the aid of said first transformation function, and the points of the surface to be inspected that are matched with them, is minimal, and said first transformation function is applied to all of the points of the reference surface in order to obtain a transformed reference surface.
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Specification