Fraunhofer-gesellschaft Zur Foerderung Der Angewandten Forschung E.v.

Ulf Hassler

Peter Schmitt

Guenther Kostka

Oliver Scholz

Randolf Hanke

Wolfgang Holub

Stefan Kasperl

Günther Kostka

Stefan Schroepfer

Ingo Bauscher

Markus Rehak

A distance measure between a beginning and an end of a material strip wound onto a body in a tangential direction can be determined by creating a height profile of a surface of the material strip, which covers the beginning and the end of the wound material strip in the tangential direction. If a position value of the beginning of the material strip is determined in the created height profile, the distance measure can be determined using this position value and the height profile covering the end of the material strip.

Apparatus and method for determining a distance measure on wound-up materials

A surface of a body includes a structure bounded by edges and a substantially edge-free unevenness. The structure is considered a quality impairment and the unevenness a potential quality impairment. A device includes a means for generating a height representation of the surface including the structure and the unevenness. A means for calculating a variation representation calculates the variation for every point of the height so that a high variation is obtained at a boundary of the structure and a low variation is obtained at a boundary of the unevenness. A means for detecting regions that potentially affect quality detects when a variation magnitude is smaller than a predetermined variation threshold value. These regions are examined to exclude uncritical regions and to determine the actual number of regions that affect quality. Quality control is performed on vehicle tires having structures such as inscriptions, and which also have bulges or constrictions that are substantially edge-free and uneven.

Device and method for a quality test of a body

A device for quality testing of a body comprising a surface comprising a structuring bounded by edges and a substantially edge-free unevenness, wherein the structuring illustrates a quality impairment and wherein the unevenness illustrates a potential quality impairment, includes a means for generating a height representation, wherein the height representation of the surface includes the structuring and the unevenness. A means for calculating a variation representation calculates the variation associated to the point for every point of the height representation, so that at a boundary of the structuring a high variation is obtained, while at a boundary of the unevenness a low variation is obtained. A means for detecting regions which are potentially quality affecting detects regions as potentially quality-affecting which comprise a variation which is smaller than a predetermined variation threshold value regarding its magnitude. These potentially quality-affecting regions may then be further examined for different criteria to exclude the uncritical regions and to find out only the actually quality-affecting regions from the number of potentially quality-affecting regions. Thus, a safe quality control of vehicle tires on which a writing is attached as a structuring and which comprises bulges or constrictions as substantially edge-free unevennesses may be obtained.

In a method for characterizing a surface comprising a localized unevenness, a contour line of the surface is initially created as a function of a location variable. Subsequently, the localized unevenness is detected in the contour line and eliminated from the contour line, so that an incomplete contour line results as a function of the location variable, which characterizes the surface without the localized unevenness. The incomplete contour line may be used to either be able to evaluate the surface without any localized points of unevenness, for example to determine the side wobble or height wobble of a tire, if the surface is a side flank and/or a running tread of a vehicle tire, or to classify the localized points of unevenness without any influence of the surface.

Measuring for device for contactless measurement of tires

An apparatus and method for establishing a correction characteristic curve for a reduction of artefacts in a tomography are described. Projection data of the object is provided, wherein the projection data comprises transmission values for the object. A representation of the object is calculated from the projection data to obtain two or three-dimensional representation data for the object. A measure for the transmission length of the object is determined by using the representation data. A transmission value, which is associated to the determined measure for the transmission length, is determined and the correction characteristic curve of several determined measures is generated for transmission lengths and associated transmission values, wherein a precorrection of the projection data can be performed by using the determined correction characteristic curve, to iteratively determine the correction characteristic curve by using the precorrected transmission values.

Apparatus and method for establishing a correction characteristic curve for a reduction of artefacts in tomography

A device for the contactless detection of a potentially existing essentially edge-free irregularity in a convex surface, which has a structuring that is delimited by edges, comprises a unit for creating a three-dimensional representation of the surface, a unit for extracting the convexity from the three-dimensional representation of the surface and for smoothing the edges of the structuring so as to obtain a convex-free representation of the convex surface which exhibits the irregularity and the structuring, whose edges have now been smoothed, a unit for comparing the convex-free representation with a threshold value so as to identify areal regions of the convex-free representation which are determined by a predetermined relationship to the threshold value, and a unit for analyzing the areas of the identified regions, a region being detected as an irregularity if its area exceeds a predetermined area. When this device is used to carry out quality control of tires, bulges or constrictions can therefore be identified with certainty in real-time operation and can be distinguished from an inscription or marking which has been intentionally provided on the tire.

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Heilsbronn, Germany

Ulf Hassler