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

• US 9,230,337 B2
• Filed: 03/21/2012
• Issued: 01/05/2016
• Est. Priority Date: 04/18/2011
• Status: Expired due to Fees

• Current Assignee: Compagnie Generale DES Etablissements Michelin SCA, Michelin Recherche et Technique SA (Compagnie Generale DES Etablissements Michelin SCA)
• Original Assignee: Compagnie Generale DES Etablissements Michelin SCA, Michelin Recherche et Technique SA (Compagnie Generale DES Etablissements Michelin SCA)
• Inventors: Zanella, Jean-Paul, Moreau, Claire, Noyel, Guillaume, Shen, Yusi
• Primary Examiner(s): Ahmed, Samir
• Application Number:
  US14/112,460
• Publication Number:
  US 20140270390A1
• Time in Patent Office: 1,385 Days
• US Class Current: 1/1
• CPC Class Codes: G06T 2207/10028 Range image; Depth image; 3D point clouds
• CPC Class Codes: G06T 5/30 Erosion or dilatation, e.g. thinning
• CPC Class Codes: G06T 5/77 Retouching; Inpainting; Scratch removal
• CPC Class Codes: G06T 7/90 Determination of colour characteristics

Abstract

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.

Claims

1. A method for processing an image of a surface of a tyre, the method comprising:

digitally processing an acquired three-dimensional digital image of the surface by using a computer processor to;

for each point of the acquired image, assign a grey-level value level corresponding to an elevation of the point;

utilize a first morphological operator, which uses a rectangular key element, to perform a closure-type first transformation of the image of the surface;

utilize a second morphological operator, which uses a rectangular key element, to perform an opening-type second transformation of the surface; and

for each point of the image, assign a grey-level value equal to a minimum value between a grey-level value of grey level at that point in a preceding step after the second transformation and a grey-level value at that point of the image, so as to eliminate false measurement points,

wherein a result of the processing of the acquired image is used to determine where the tyre is in compliance with a reference.

2. The method according to claim 1, wherein the first morphological operator used for the first transformation is a rectangle of which:

a length in a circumferential direction of the tyre is between 50 and 100 pixels, and

a width in a direction perpendicular to the circumferential direction is less than 10 pixels.

3. The method according to claim 1, wherein the second morphological operator used for the second transformation is a rectangle of which:

a length in a circumferential direction of the tyre is between 500 and 1000 pixels, and

a width in a direction perpendicular to the circumferential direction is less than 10 pixels.

4. The method according to claim 2, wherein the second morphological operator used for the second transformation is a rectangle of which:

a length in a circumferential direction of the tyre is between 500 and 1000 pixels, and

a width in a direction perpendicular to the circumferential direction is less than 10 pixels.

5. The method according to claim 1, wherein the acquired image is that of an internal surface of the tyre.

6. The method according to claim 2, wherein the acquired image is that of an internal surface of the tyre.

7. The method according to claim 3, wherein the acquired image is that of an internal surface of the tyre.

8. The method according to claim 4, wherein the acquired image is that of an internal surface of the tyre.