Compagnie Generale Des Etablissements Michelin

Commissariat &#xc0; L'&#xc9;nergie Atomique Et Aux &#xc9;nergies Alternatives

Michelin Recherche Et Technique S.a.

Compagnie Generale Des Establissements Michelin

Societe Detechnologie Michelin

Steve Bourgeois

Alexandre Joly

Régis Vinciguerra

Christian Leobal

Claire Moreau

Sylvie Naudet

François Gaspard

Michel Dhome

Mohamed Tamaazousti

Alexandre Chariot

Vincent Gay-Bellile

Dorra Larnaout

A method for calibrating an augmented reality visual rendering system comprising at least one display device partially transparent with respect to the user thereof, comprises carrying out the steps of: displaying a two-dimensional calibration curve on a partially transparent display device of the partially transparent display device; recording a three-dimensional curve described by the user by a three-dimensional pointing device so that the trajectory described by the three-dimensional pointing device is aligned, according to the viewpoint of the user, with the two-dimensional calibration curve displayed on the display device; and matching the three-dimensional curve and the two-dimensional calibration curve displayed on the display device; and comprising a step of calibrating the augmented reality visual rendering system by determining the parameters of a model to represent the set comprising the eye of the userand the partially transparent display device of the partially transparent display device at which the eye is looking, on the basis of matching.

Method for calibrating an augmented reality visual rendering system comprising at least one display device that is partially transparent with respect to the user thereof, and associated system

A method for inspecting a tire's surface includes: capturing a reference image of a reference tire's surface relief elements and transmitting data of the reference image to a processor; parameterizing main characteristics of the reference image via interaction of an operator with the processor; producing a reference map of the surface relief elements by dividing the reference image into a plurality of reference zones of interest; assigning a specific registration and checking algorithm to each of the reference zones of interest; capturing an inspection image of a tire under inspection; and, after completion of pre-processing of the inspection image, automatically: superimposing the reference map on the inspection image, and, for each of a plurality of zones of interest of the inspection image, running the specific registration and checking algorithm for a corresponding one of the reference zones of interest, to determine a conformity of the tire under inspection.

Optimized method for analyzing the conformity of the surface of a tire

To analyze a tire surface, a 3D elevational image is captured, which is formed of pixels representing points on the surface. Each point is assigned a grey-level value proportional to its elevation relative to a surface level. Based on the elevations in the elevational image, an orientational image is formed showing elevation gradients of the surface. In the orientational image, which is formed of pixels representing points on the surface, each point is assigned a grey-level value proportional to an angle formed with a direction given by a projection in an image plane of a non-zero norm vector substantially corresponding, at this point, to a gradient vector tangent to the surface and oriented in a direction of greatest slope. A filtered image is determined by transforming the orientational image using a filter to select areas that include structures similar to those in a reference orientational image of a blow hole.

Method for processing a digital image of the surface of a tyre in order to detect an anomaly

A method for locating a camera and 3D reconstruction of its static environment, comprising an object of interest, the 3D model of which is known, includes: calculating an initial pose of the camera in the environment and an initial reconstruction; calculating the pose of the camera for each new image by pairing 3D primitives of the environment with 2D primitives of said image and reconstructing 3D primitives of the environment by triangulation; and simultaneously optimizing the poses of the camera and 3D primitives by minimizing a reprojection error over a plurality of images. The 3D model is a geometric description of the object of interest, the reprojection error has only two types of terms, a first type associated with primitives constrained by the 3D model and a second type associated with primitives of the environment other than the object, the optimization associating the primitives with the environment or 3D model.

Method for locating a camera and for 3D reconstruction in a partially known environment

A method for inspecting a portion of a tire 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.

Method for the pre-processing of a three-dimensional image of the surface of a tyre for use in the inspection of said surface

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.

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Choisy le Roy, France

Steve Bourgeois