Compagnie Generale Des Etablissements Michelin

Michelin Recherche Et Technique S.a.

Michelin Recherche Et Techniques S.a.

Societe Detechnologie Michelin

Claire Moreau

Jean-Paul Zanella

Guillaume Noyel

Yusi Shen

Alexandre Joly

Steve Bourgeois

Christian Leobal

Régis Vinciguerra

François Gaspard

A method for processing an image of a surface of a tire to be inspected is described. A three-dimensional digital image is captured of the surface, and each pixel of a plane of the image is assigned an item of information relating to an elevation of the pixel with respect to the surface. By utilizing of a morphological operator that uses a structuring element, a first transformation of the image of the surface is performed with aid of an opening and then of a closing, so as to tailor a grey level of pixels situated abnormally above or below the surface.

Analysis of the digital image of the external surface of a tyre and processing of false measurement points

A method for processing an image of a surface of a tire under inspection is described. A three-dimensional digital image of the surface is captured and, for each point of the captured image, a grey-level value corresponding to an elevation is assigned to the point. Utilizing a first morphological operator that uses a rectangular key element, a closure-type first transformation of the image of the surface is carried out. Utilizing a second morphological operator that uses a rectangular key element, an opening-type second transformation of the surface is carried out. For each point of the image, a grey-level value equal to a minimum value between a grey-level value at that point obtained in a preceding step and a grey-level value at that point is assigned, so as to eliminate false measurement points.

Analysis of the digital image of the internal surface of a tyre and processing of false measurement points

In a method for processing an image of a surface of a tire, a 3D digital image of the surface is captured, and each pixel of the captured image is assigned a grey level value proportional to an elevation of a corresponding point with respect to the surface. The pixels are placed in rows and columns. A search is made for zones of the surface that include pixels having a grey-level value lower than a given threshold. Boundaries of an encompassing box that includes one or more of the zones are determined. Inside the encompassing box, a grey-level value equal to a mean grey-level value of a set of reference pixels (K, s) positioned in a zone situated in immediate proximity to a pixel under consideration is assigned to each of the pixels whose grey-level value is lower than the given threshold.

Analysis of the digital image of the surface of a tyre and processing of non-measurement points

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.

Method for processing a three-dimensional image of the surface of a tire so that it can be used to inspect the said surface

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Clermont-Ferrand, France

Claire Moreau