US 9,551,671 B2Granted

Method and device for detecting, in particular, refracting defects

AssigneeMsc & Sgcc

InventorsOlivier Colle, Florence Drouet, Marc Leconte

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Abstract

An in-line method for optically inspecting transparent or translucent containers (3) comprises illuminating each container with a light source that presents light intensity variation in a periodic pattern along at least a first variation direction. A number N greater than or equal to three of images of the container traveling in front of the light source and occupying N different respective positions along the travel path is taken. Between taking successive images, a relative shift between the container and the periodic pattern is created. A geometrical transformation is determined and applied in order to put the pixels belonging to the container in the N successive images of the same container into coincidence. A phase image for each container is constructed using the N registered images of the container. The phase image is analyzed in order to deduce therefrom at least the presence of defects or the quality of the container.

Claims20

Dependent claims

A method of an in-line method of optically inspecting transparent or translucent containers (3) traveling along a determined path F1 at a high rate between a light source (7) and an image-taking system (9) for taking images of the containers and for analyzing the images taken, in order to determine as a characteristic of the container (3) at least the presence of a defect that refracts light or the quality with which the material constituting the container is distributed, the method being characterized by the following steps:

illuminating each container (3) traveling at a high rate by means of the light source (7) that presents light intensity variation in a periodic pattern (71) of period T1 along at least a first variation direction (D);
for each container (3), taking a number N greater than or equal to three of images of the container traveling in front of the light source and occupying N different respective positions along the travel path;
between taking successive images, creating a relative shift between the container and the periodic pattern in a variation direction (D) of the periodic pattern (71);
determining and applying a geometrical transformation in at least N−1 images of the same container for at least a set of points belonging to the container in order to put the pixels belonging to the container in the N successive images of the same container into coincidence;
for each container (3) using the N registered images of the container, constructing a phase image;
and
analyzing the phase image in order to deduce therefrom, as a characteristic of the container (3), at least the presence of a defect that refracts light or the quality of the distribution of the material constituting the container.

4 more elements

An installation for in-line inspection of transparent or translucent containers (3) in order to detect characteristics of the containers, the installation comprising conveyor means (2) for conveying the containers (3) so that they travel through an inspection station (5) made up of at least one light source (7) placed on one side of the traveling containers and at least one image-taking system (9) for taking images of the containers arranged on the other side of the containers, together with a unit for analyzing the images taken, the installation being characterized in that:

the light source (7) presents light intensity variation with a periodic pattern of period T1 along at least a first variation direction (D);
a first image-taking system (9) is suitable for taking a number N greater than or equal to three of images of each container placed in front of the light source, with a relative shift being created between the container (3) and the periodic pattern (71) along a variation direction (D) of the periodic pattern (71) between taking successive images;
and
the control and processor unit (13) comprises:
means for determining and applying a geometrical transformation in at least N−1 images of the same container coming from the first image-taking system in order to put into coincidence pixels of the container in the N successive images of the same container as put into register in this way;
means for calculating at least one phase image from N registered images of the container;
and
means for analyzing the phase images in order to deduce therefrom, as a characteristic of the container, (3) at least the presence of a defect that refracts light or the quality of the distribution of the material constituting the container.

5 more elements

Dependencies are inferred from the claim text.

Facts

Application: 14/416,369Filed 18 Jul 2013
Priority: FR 12 5711723 Jul 2012
Published: US 2015/0204797 A123 Jul 2015
Granted: 24 Jan 2017
Term ends: Not estimatedThe source records don’t support an estimate.

Classification7 codes

G01N 21/90
Investigating the presence of flaws or contamination: in a container or its contents
G01N 21/8851
Investigating the presence of flaws or contamination: scan or image signal processing specially adapted therefor, e.g. for scan signal adjustment,…
G01N 21/958
Characterised by the material or shape of the object to be examined: inspecting transparent materials or objects, e.g. windscreens
G01N 2021/8832
Shadow projection or structured background, e.g. for deflectometry: structured background, e.g. for transparent objects