# US 2018/0321114 A1 · Station and method for checking tyres

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- Number: US 2018/0321114 A1
- Document ID: US20180321114A1
- Status: Published application
- Kind: A1
- Application number: 15/772,804
- Filed: 2016-12-20
- Published: 2018-11-08
- Earliest claimed: 2015-12-22
- Assignees: Pirelli Tyre S.p.A.
- Applicants: Pirelli Tyre S.P.A.
- Inventors: Alessandro HELD; Vincenzo BOFFA; Bartolomeo MONTRUCCHIO
- Web page: https://patentgrep.com/patent/US20180321114A1

## CPC

- G01M 17/027: {using light, e.g. infrared, ultraviolet or holographic techniques}
- G01B 11/24: for measuring contours or curvatures
- G01N 21/8851: {Scan or image signal processing specially adapted therefor, e.g. for scan signal adjustment, for detecting different kinds of defects, for compensating for structures, markings, edges (G01N21/8806 and G01N21/93 - G01N21/95692 take precedence; optical measurement of dimensions G01B11/00; optical scanning G02B26/10; image transformation G06T3/00; computerised image enhancement G06T5/00; image processing per se for flaw detection G06T7/0002)}
- G01N 21/952: Inspecting the exterior surface of cylindrical bodies or wires (G01N21/956 takes precedence)
- G01N 21/954: Inspecting the inner surface of hollow bodies, e.g. bores
- G06T 7/0004: {Industrial image inspection}
- G01N 21/95: characterised by the material or shape of the object to be examined (G01N21/89 - G01N21/91, G01N21/94 take precedence)
- G01N 2021/8887: {based on image processing techniques}
- G01M: TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)
- G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL

## Abstract

Apparatus and method for checking tyres in a tyre production line. The apparatus includes a support frame for mounting the tyre, a flange for attaching the support frame to a movement member, and an acquisition system for acquiring digital images of a surface of the tyre. The acquisition system includes a linear camera and an illumination system for illuminating an objective line of the camera. The illumination system includes a light source and an optical lens system having a second optical axis. The optical lens system includes first and second converging lenses arranged on the side opposite the light source with respect to the first lens so that the light source, the first lens and the second lens are coaxial with the second optical axis.

## Claims

### Claim at position 1

-31. (canceled)

### Claim 32

A station for checking tyres in a tyre production line, comprising:
a) a support adapted to support a tyre set on a sidewall thereof and to rotate the tyre around a rotation axis thereof;
b) an apparatus; and
c) a movement member,
wherein the apparatus comprises:
b1) a support frame;
b2) a flange for attaching said support frame to the movement member; and
b3) an acquisition system for acquiring digital images of a surface of the tyre mounted on the support frame, the acquisition system comprising:
b3i) a linear camera having a first optical axis, an optical plane, a focal plane and an objective line belonging to the focal plane and to the optical plane, and
b3ii) an illumination system adapted to illuminate the objective line, the illumination system comprising a light source and an optical lens system having a second optical axis,
wherein the optical lens system comprises a first converging lens, proximal to the light source, and a second converging lens arranged on the side opposite the light source with respect to the first lens,
wherein the light source, the first lens and the second lens are coaxial with the second optical axis,
wherein the first lens has a numerical aperture greater than or equal to 0.5, and
wherein an aperture of the second lens is greater than the numerical aperture of the first lens.

### Claim 33 (depends on 32)

The station according to claim 32, wherein the light source has an overall emitting surface inscribed in a circle with diameter less than or equal to 10 mm.

### Claim 34 (depends on 33)

The station according to claim 33, wherein the circle has a diameter greater than or equal to 3 mm.

### Claim 35 (depends on 32)

The station according to claim 32, wherein the light source has an emitting surface with an optical power density greater than or equal to 0.3 W/mm2.

### Claim 36 (depends on 32)

The station according to claim 32, wherein the light source is adapted to emit incoherent light.

### Claim 37 (depends on 32)

The station according to claim 32, wherein the light source is an LED.

### Claim 38 (depends on 32)

The station according to claim 32, wherein the light source has an emitting surface with circular shape.

### Claim 39 (depends on 32)

The station according to claim 32, wherein the first lens has a numerical aperture greater than or equal to 0.6.

### Claim 40 (depends on 32)

The station according to claim 32, wherein the aperture of the first lens has a diameter greater than or equal to 15 mm and smaller than or equal to 35 mm.

### Claim 41 (depends on 32)

The station according to claim 32, wherein a rear focal length of the first lens is greater than or equal to 7 mm and smaller than or equal to 20 mm.

### Claim 42 (depends on 32)

The station according to claim 32, wherein the first lens is aspherical.

### Claim 43 (depends on 32)

The station according to claim 32, wherein the second lens has a front focal length greater than or equal to 80 mm and smaller than or equal to 200 mm.

### Claim 44 (depends on 32)

The station according to claim 32, wherein the second lens has a numerical aperture smaller than or equal to 0.4.

### Claim 45 (depends on 32)

The station according to claim 32, wherein the aperture of the second lens has a diameter greater than or equal to 30 mm and smaller than or equal to 60 mm.

### Claim 46 (depends on 32)

The station according to claim 32, wherein the second lens has at least one spherical surface, preferably with curvature radius greater than or equal to 40 mm and less than or equal to 60 mm.

### Claim 47 (depends on 46)

The station according to claim 46, wherein the spherical surface has a curvature radius greater than or equal to 40 mm and smaller than or equal to 60 mm.

### Claim 48 (depends on 32)

The station according to claim 32, wherein the second lens is a plano-convex lens with a single convex surface facing the first lens.

### Claim 49 (depends on 32)

The station according to claim 32, wherein the first lens and the second lens are positioned so that respective convex surfaces face each other.

### Claim 50 (depends on 32)

The station according to claim 32, wherein a difference between a diameter of the aperture of the second lens and a diameter of the aperture of the first lens is:
greater than or equal to 40% of the diameter of the aperture of the first lens, and
smaller than or equal to 100% of the diameter of the aperture of the first lens.

### Claim 51 (depends on 32)

The station according to claim 32, wherein a difference between a diameter of the aperture of the second lens and a diameter of the aperture of the first lens is:
greater than or equal to 70% of a distance between a rear vertex of the first lens and a rear vertex of the second lens, and
smaller than or equal to 130% of the distance between the rear vertex of the first lens and the rear vertex of the second lens.

### Claim 52 (depends on 32)

The station according to claim 32, wherein a distance between a rear vertex of the first lens and a rear vertex of the second lens is fixed, and greater than or equal to 10 mm and less than or equal to 20 mm.

### Claim 53 (depends on 32)

The station according to claim 32, wherein the illumination system comprises a system for regulating an axial distance between the light source and the first lens.

### Claim 54 (depends on 32)

The station according to claim 32, wherein an axial distance between the light source and a rear vertex of the first lens is smaller than or equal to a rear focal length of the first lens.

### Claim 55 (depends on 54)

The station according to claim 54, wherein a difference between the rear focal length and the axial distance between the light source and the rear vertex of the first lens, is greater than or equal to 5% of the rear focal length and smaller than or equal to 30% of the rear focal length.

### Claim 56 (depends on 54)

The station according to claim 54, wherein an axial distance between a front vertex of the second lens and a point of intersection between the second optical axis and the focal plane is less than a front focal length of the second lens.

### Claim 57 (depends on 54)

The station according to claim 54, wherein the illumination system defines an image plane of the light source lying at an axial distance from a front vertex of the second lens that is greater than or equal to a front focal length of the second lens.

### Claim 58 (depends on 57)

The station according to claim 57, wherein a point of intersection between the image plane and the second optical axis, and a point of intersection between the second optical axis and the focal plane, are separated by at least 20 mm.

### Claim 59 (depends on 32)

The station according to claim 32, wherein the second optical axis forms, with the optical plane, an angle that is less than or equal to 15° in absolute value.

### Claim 60 (depends on 32)

The station according to claim 32, wherein the second optical axis intersects the first optical axis.

### Claim 61 (depends on 32)

The station according to claim 32, wherein the second optical axis intersects the objective line.

### Claim 62

A method for checking tyres, the method comprising:
a) arranging an acquisition system comprising:
a linear camera having a first optical axis, an optical plane, a focal plane, and an objective line belonging to the focal plane and to the optical plane; and
an illumination system adapted to illuminate the objective line, the illumination system comprising a light source and an optical lens system having a second optical axis,
wherein the optical lens system comprises a first converging lens proximal to the light source, and a second converging lens arranged on a side opposite the light source with respect to the first converging lens,
wherein the light source, the first converging lens and the second converging lens are coaxial with said second optical axis,
wherein the first converging lens has a numerical aperture greater than or equal to 0.5; and
wherein an aperture of the second converging lens is greater than an aperture of the first converging lens;
b) arranging a tyre to be checked having a surface and moving the acquisition system close to the tyre;
c) rotating the tyre with respect to the acquisition system in a manner that distinct linear surface portions of the tyre are successively situated in proximity to the objective line; and
d) successively acquiring, by means of the acquisition system, a series of respective linear images of the distinct linear surface portions to obtain an image of a circumferential surface region via combining of the series of respective linear images.

### Claim 63 (depends on 62)

The method according to claim 62, wherein:
the circumferential surface region is a circumferential external surface region of at least one of: i) a shoulder, ii) a tread, and iii) a bead, of the tyre, and
the first optical axis is substantially radially arranged with respect to the tyre.