EP1931974A1

EP1931974A1 - Method and installation for detecting foreign bodies inside a container

Info

Publication number: EP1931974A1
Application number: EP06808282A
Authority: EP
Inventors: Thomas Leclerc; Christophe Venaille; Olivier Gebelin
Original assignee: Tiama SA
Current assignee: Tiama SA
Priority date: 2005-09-05
Filing date: 2006-09-05
Publication date: 2008-06-18
Also published as: ZA200802082B; BRPI0615467A2; FR2890447B1; FR2890447A1; US20100220919A1; CN101287981A; WO2007028924A1

Abstract

The invention concerns an installation for detecting inside a container the presence of a foreign body (3). The installation comprises: means (4) for moving the container (2) so that it occupies a characteristic position wherein the foreign body (3) present is placed outside a confinement zone (5) of the container; means for moving the container so that it occupies another characteristic position wherein a foreign body present is placed inside said confinement zone (5) of the container; first and second imaging systems (10) adapted to produce at least one image of the confinement zone (5) of the container when the latter occupies its characteristic positions; and a unit for processing and analyzing the images produced by the imaging systems (10) to determine the presence or not of a foreign body.

Description

METHOD AND INSTALLATION FOR DETECTING FOREIGN BODIES INSIDE A CONTAINER

The present invention relates to the technical field of the inspection of translucent or transparent hollow articles or articles containing a liquid in particular of transparent or translucent nature.

The object of the invention is more specifically the inspection of such containers for the purpose of detecting, inside, the presence of foreign bodies in the general sense, with a density higher than that of the liquid.

The object of the invention finds a particularly advantageous application for the detection of glass debris likely to be present inside containers such as bottles made of glass.

In the preferred field of application above, it appears the need to inspect the bottles in order to search for the possible presence of glass debris. In the state of the art, there is a first category of detection to move the glass debris inside the container. Thus, it has been proposed by WO 96/18883, a detection method in which the bottle is turned so as to move the debris inside the liquid. Images are taken successively in a small time interval allowing, by difference, to observe the movement of the debris.

The major drawback of this technique lies in the fact that it is necessary to monitor the imaging area for a relatively long period of time to account for the fall of a debris. Such subjection imposes either very slow work rates, or many images taken and a large number of cameras. In addition, the detection is based on a difference in images that can be very sensitive to noise related to real industrial conditions such as bubbles in the liquid or drops on the wall of the bottle.

In the state of the art, there is a second category of detection for placing the glass debris present in a confinement zone in order to limit the inspection to this confinement zone. So, the patent application FR 2,725,274 describes an installation implementing means for moving the bottle imposing a sequence of movements for placing the foreign body in a stable zone and without etching, namely the shoulder of the bottle. Such a solution is tricky to implement for bottles with a shoulder not very marked. Moreover, the centrifugal force applied to the foreign bodies prevents them from remaining in a stable observation zone. It also turns out that the time of placement of the foreign body in this area renders this process unusable for high inspection rates.

For the same purpose, US Pat. No. 4,209,802 proposed to incline the container relative to the vertical by an angle of the order of 45 ° in order to ensure the confinement of foreign bodies in an inspection zone making part of the bottom of the container. The inspection area of the container is illuminated and the light transmitted by the container is recovered by a camera whose video signal is analyzed to determine the presence or absence of a foreign object. It should be considered that the foreign object containment zone corresponds to a part of the bottle having many engravings or marks, such as notches, code beads or mold seals. Also, the technique proposed by this patent does not reliably distinguish foreign bodies located at the bottom of the bottle and the various markings made on the bottle, resulting in the rejection of bottles containing no foreign bodies.

Analysis of the many solutions of the state of the art shows that there is a need for a technique for detecting the presence of foreign bodies inside a container with a high inspection rate. by eliminating false detections linked in particular to the presence of numerous markings on the containers.

The object of the invention is therefore to provide a method for reliably and reliably detecting the presence of foreign bodies inside containers with a high inspection rate while avoiding the rejection of containers that do not include foreign bodies. To achieve such an objective, the detection method comprises the following steps:

choosing a so-called containment container zone in which a foreign body present is brought by gravity,

- move the container so as to place the foreign body present outside the confinement zone,

taking at least one image of the confinement zone when the container occupies a characteristic position in which the foreign body present is placed outside the confinement zone,

- move the container so as to place the foreign body in the containment zone,

taking at least one image of said confinement zone when the container occupies another characteristic position in which the foreign body present is placed in the confinement zone,

and analyzing the images taken to detect the presence of a foreign body present inside the container.

According to a first variant embodiment, the method consists of moving the container first so as to place the foreign body present outside the confinement zone and then moving the container so as to place the foreign body present in the zone. confinement.

According to a second variant embodiment, the method consists in moving the container first so as to place the foreign body present in the confinement zone and then moving the container so as to place the foreign body present outside the zone. confinement.

For example, the method involves placing the foreign body in a containment zone of the bottle such as the jable, the shoulder or the stopper.

Advantageously, the method consists in taking images of the confinement zone by making part of the container appear in the image.

According to a characteristic of the invention, the method consists in moving the container so as to place the foreign body present outside and in the confinement zone by subjecting the container to tilting movements in the opposite direction.

Another object of the invention is to provide an installation for reliably and reliably detecting the presence of foreign bodies inside containers with a high inspection rate while avoiding the rejection of containers containing no foreign bodies. .

To achieve such an objective, the installation according to the invention comprises:

means for moving the container so that it occupies a characteristic position in which a foreign body present is placed outside an area of the container for confining said foreign body,

means for moving the container so that it occupies another characteristic position in which a foreign body present is placed in said confinement zone of the container,

a first imaging system adapted to take at least one image of the confinement zone of the container when the latter occupies a characteristic position,

a second imaging system adapted to take at least one image of the confinement zone of the container when the latter occupies its other characteristic position,

and a unit for processing and analyzing the images taken by the imaging systems in order to determine the presence or absence of a foreign body.

Advantageously, the means for moving the container so that it occupies a characteristic position are adapted to incline the container relative to the vertical by a determined angle α while the means for moving the container so that it occupies its other characteristic position. are adapted to incline the container relative to the vertical of an angle of opposite sign to the determined angle α.

Advantageously, the imaging systems have inclined viewing axes relative to the longitudinal axis of the container at angles of equal values and opposite signs. According to an exemplary embodiment, each imaging system comprises a camera and a light source, placed on either side of the container, and adapted to detect defects by transmission.

According to another exemplary embodiment, each imaging system comprises a camera and a lighting source adapted to detect defects by reflection.

According to a preferred embodiment, the means for moving the container comprise a carousel rotating about a vertical axis and equipped with a series of means for gripping the radially distributed containers, the gripping means being controlled in displacement so that on one turn, each container occupies its two characteristic positions in which a foreign body present is placed in or outside the confinement zone.

Various other characteristics appear from the description given below with reference to the accompanying drawings which show, by way of non-limiting examples, embodiments of the subject of the invention.

Figures 1 and 2 are diagrams explaining the principle of a detection device according to the invention.

Figures 3 and 4 are views of exemplary images taken when a container occupies characteristic positions illustrated respectively in Figs. 1 and 2.

Figure 5 is a view of an exemplary embodiment of an installation according to the invention.

As it appears from the Fíg. 1 and 2, the installation 1 according to the invention is designed to allow the control of hollow articles or containers 2 made of a transparent or translucent material such as glass. In the preferred example described below, the controlled containers are bottles made of glass but it must be considered that the invention extends to any packaging for a liquid having as a constituent material of the packaging, a transparent or translucent nature. The installation 1 according to the invention is designed to detect inside the container, the presence of a foreign body 3, in the general sense, higher density than the liquid. The object of the invention finds a particularly advantageous but nonlimiting application for detecting in time foreign body, a glass debris but it must be considered that the object of the invention makes it possible to detect any type of foreign body to the liquid , of higher density than that of the liquid.

Preferably, the detection device 1 according to the invention is placed on the conveyor chain of the containers 2, at a control station located downstream of the bottling station.

According to the invention, the installation 1 comprises means 4 for moving the container 2 so that it occupies a first characteristic position, said with foreign body, as illustrated in FIG. 1 in which a foreign body present 3 is placed inside a confinement zone 5 of the foreign body 3. It must be considered that the confinement zone 5 corresponds to a zone of the container in which a foreign body 3 present in the the inside of the container is brought by gravity. In the illustrated example, the selected confinement zone 5 is located at the junction of the body 6 and the bottom 7 of the container also called jable. More specifically, the confinement zone 5 corresponds to a portion of the jail extending over a portion of the perimeter of the jable, less than half the perimeter of the container. Of course, another containment zone 5 may be chosen in which the foreign bodies 3 are conveyed by gravity. Thus, it can be chosen a confinement zone 5 corresponding to the shoulder of the container or the stopper on which the foreign bodies come in the inverted position of the container.

The displacement means 4 are made by any mechanical device for ensuring on the conveyor line, the passage of the containers 2 from the vertical position to a first characteristic position in which a foreign body 3 present inside the container is placed within the selected confinement zone 5. Advantageously, the displacement means 4 make it possible to incline the container relative to the vertical by a determined angle formed between the vertical and the longitudinal axis of symmetry of the bottle. For example, the angle α is between 10 ° and 80 ° and preferably of the order 50 °. The inclination of the container 2 leads the possible foreign bodies 3 present to migrate towards the bottom of the container in order to establish itself in the confinement zone 5. As is clear from FIG. 1, the confinement zone 5 corresponds for the first characteristic position of the container 2 to the part of the jail situated at the lowest level.

It should be understood that the container 2 is inclined so that at the expiration of the maximum migration time of the foreign bodies 3, the container is placed in position to be controlled. The inclination of the container 2 allows to place the foreign bodies 3 in a stable zone which is the jable of the bottle. The inspection of this confinement zone 5 is sufficient to detect the possible presence of foreign bodies which, under the effect of gravity, are inevitably brought to the bottom of the container. It should be noted that the confinement zone 5 is limited in relation to the size of the bottle.

According to another characteristic of the invention, the installation 1 comprises a first imaging system 10 adapted to take at least one image Ii of the confinement zone 5 of the container when the latter occupies its first characteristic position illustrated in FIG. Fig. 1. This first imaging system 10 comprises a lighting source 11 of any known type as well as a video camera 12 of any type making it possible to observe at least the confinement zone 5.

In the illustrated example, the camera 12 and the light source 11 are arranged on either side of a container 2. The camera 12 has a viewing axis X which is inclined by an angle β for example understood between 90 ° and 135 ° with respect to the longitudinal axis of the container. In this example, the foreign bodies 3 are detected by transmission. Thus, the lighting is of the transmission type so that the foreign bodies 3 are revealed by attenuation of light by absorption or refraction effect. Of course, reflective lighting can also be used to illuminate the foreign bodies so that it reflects the light towards the camera. According to another embodiment, it may be envisaged to implement both reflective lighting and transmission lighting.

The first imaging system 10 makes it possible to take at least one image when a foreign body 3 present inside the container is inevitably positioned in the confinement zone 5. As can be seen from FIG. 3, an image II of the confinement zone 5 reveals the foreign body 3 present. According to a preferred embodiment, the camera 12 is placed relative to the container so that the image taken Ii makes part of the container 2 appear as the wall of the container corresponding to the junction between the body 6 and the bottom 7 of the container or the cap fitted to the container 2. Thus, the image shows the interface zone between the liquid and the container so that the part of the container appearing on the image constitutes a reference zone for the image processing.

According to another characteristic of the invention illustrated particularly in the Fíg. 2, the installation 1 comprises means 4 'for moving the container so that it occupies a second characteristic position, known as a foreign body, in which a foreign body 3 present is placed outside the selected confinement zone 5. Advantageously, the displacement means 4 'make it possible to incline the container relative to the vertical by a determined angle ai of sign opposite to the angle α chosen to place the container in its first characteristic position. The angle ai may have a value equal to or different from the value α. For example, the angle ai may be of the order of -15 °.

It must be considered that the displacement means 4 'are adapted so that a foreign body 3 present inside the container is brought by gravity into a positioning or recovery zone 5' which is different from the selected confinement zone 5. In the example illustrated in FIG. 2, the recovery zone 5 'of the foreign body 3 corresponds to a part of the jabl located at the opposite part of the jable corresponding to the confinement zone 5. As is more particularly apparent from FIG. 2, in the second characteristic position of the container, the confinement zone 5 corresponds to the portion of the jabla located at the highest level while the recovery zone 5 'corresponds to the part of the jabla located at the lowest level. The confinement 5 and recovery 5 'zones are therefore disjoint.

The installation 1 also comprises a second imaging system 20 adapted to take at least one image of the confinement zone 5 of the container when the latter occupies its second characteristic position illustrated in FIG. 2. This second imaging system 20 comprises a lighting source 21 of any known type and a video camera 22 of any type known also. In the illustrated example, the camera 22 and the light source 21 are arranged on either side of the container so that the foreign bodies are detected by transmission. Of course, it may be provided that the second image pickup system 20 includes reflective illumination possibly associated with transmission lighting. The camera 22 has a line of sight Xi inclined with respect to the longitudinal axis of the container by an angle βi of value equal to the angle β but being of opposite sign.

The second imaging system 20 makes it possible to take at least one image when a foreign body 3 present is inevitably positioned outside the selected confinement zone 5. As can be seen from FIG. 4, the image I ₂ of the confinement zone 5 does not include the foreign body 3. Of course, the camera 22 takes, when the container occupies its second characteristic position, an image of the confinement zone 5 which is identical to the confinement zone 5 taken in the first characteristic position of the container. So, it appears on the image I ₂ , the same part of the container 2 that appears on the image Ii. The image I ₂ is identical to the image Ii with the exception of the foreign body 3.

The detection device 1 according to the invention also comprises a unit for processing and analyzing the images taken by the imaging systems 10, 20, in order to determine the presence or absence of a foreign body to the inside the container. This unit, not shown, comprises processing means and image analysis Ii, I ₂ taken in the two characteristic positions of the container. These means compare the images taken to detect the presence or absence of a foreign body 3.

The installation 1 described above makes it possible to implement a detection method that derives directly from the foregoing description.

It must be considered that a zone of the so-called confinement container 5 is chosen in which a foreign body 3 present inside the container 2 is inevitably brought by gravity. In the illustrated example, the confinement zone 5 corresponds to a part of the jable of the container.

The method consists of moving the container 2 so as to place the foreign body 3 present inside the confinement zone 5 (FIG 1). The method consists in taking at least one image of the confinement zone 5 when the container occupies this first characteristic position in which the foreign body 3 present is placed in the confinement zone 5. An image II is thus obtained, revealing the presence of a foreign body 3.

According to a preferred embodiment, the image taken takes into account at least part of the container namely a part of the wall or part of the plug in the case where the confinement zone is located at the neck of the container.

The method according to the invention then consists in moving the container so as to place the foreign body 3 present outside the selected confinement zone 5. As it appears more specifically in FIG. 2, the foreign body 3 is thus placed in another part of the jail, namely a recovery zone 5 'which is disjunct from the confinement zone 5 chosen. At least one image I ₂ of the confinement zone 5 is then taken when the container occupies this second characteristic position in which the foreign body present 5 is placed outside the confinement zone (FIG 2). As can be seen from FIG. 4, the image taken I ₂ corresponds to the same zone of the container appearing in the image Ii but in which the foreign body 3 is absent.

The images Ii, I ₂ taken are then analyzed for the presence of a foreign body inside the container 2. Insofar as the images taken reveal the same part of the container and possibly a foreign body 3 for the first time. image II, the comparative analysis of the two images makes it possible to highlight the presence or absence of a foreign body 3. The analysis of the images can consist in making a difference between the images or in extracting the characteristics (geometrical and photometric) each of the images to compare them later. It should be noted that the image I ₂ free of foreign bodies can constitute a reference image.

In the foregoing description, the method aims to first move the container 2 so as to place the foreign body 3 present in the confinement zone 5 and then move the container 2 so as to place the foreign body 3 present out of the confinement zone, that is to say in the recovery zone 5 '.

According to a preferred embodiment, it should be noted that the method consists in moving the container 2 first so as to place the foreign body 3 present outside the confinement zone 5, that is to say in the zone 5 'recovery (Fig 2) and then move the container 2 so as to place the foreign body 3 present in the confinement zone 5 (Fig 1).

The Fíg. 5 illustrates an exemplary embodiment of an installation implementing the method according to the invention. As is more clearly apparent from FIG. 5, the installation 1 comprises a carousel rotating around a vertical axis A provided as displacement means 4, 4 ', of a series of gripping tongs 31 circumferentially distributed next to each other and mounted to each grasp a container 2 for example by its neck. The installation comprises an input station 32 adapted to successively bring the containers 2 in the upright position to be grasped by the gripping tongs 31. The installation also comprises an exit station 33 situated near the entry station allowing transferring, on the one hand, the receptacles containing foreign bodies to an ejection outlet 34 and, on the other hand, the receptacles containing no foreign bodies 3 to an exit conveyor 35.

Between the entry station 32 and the exit station 33, the containers 2 pass successively in front of the imaging systems 20, which are fixed. Thus, the gripping tongs 31 are controlled in displacement so that on one turn of the carousel, each container 2 occupies the two characteristic positions defined above. Each container 2 is thus moved to be placed in front of the imaging system 20 in an inclined position making it possible to place the foreign body present 3 outside the confinement zone 5, that is to say in the recovery zone. 5 '(Fig. 2) to then be moved to the imaging system 10 in which the foreign body 3 present is placed in the confinement zone 5 (Fig. 1). Each container 2 is thus subjected to tilting movements in the opposite direction. Of course, upstream of the imaging systems 10, 20, the container 2 can undergo different movements in order to surely cause all the foreign bodies 3 present in or outside the selected confinement zone 5.

The invention is not limited to the examples described and shown because various modifications can be made without departing from its scope.

Claims

1 - Method for detecting, inside a transparent or translucent container (2) containing a liquid, the presence of a foreign body (3) with a density greater than that of the liquid, the method comprising the following steps:

choosing a so-called containment container zone (5) into which a foreign body present is brought by gravity,

moving the container so as to place the foreign body (3) present outside the confinement zone (5),

taking at least one image (I2) of the confinement zone (5) when the container occupies a characteristic position in which the foreign body present is placed outside the confinement zone,

- moving the container so as to place the foreign body in the confinement zone (5),

taking at least one image (Ii) of said confinement zone (5) when the container occupies another characteristic position in which the foreign body present is placed in the confinement zone (5),

and analyzing the images taken (Ii, I ₂ ) to detect the presence of a foreign body (3) present inside the container.

2 - Process according to claim 1, characterized in that it consists in moving first the container (2) so as to place the foreign body (3) present outside the confinement zone (5) and, to move then the container (2) so as to place the foreign body (3) present in the confinement zone (5).

3 - Process according to claim 1, characterized in that it consists in moving first the container (2) so as to place the foreign body (3) present in the confinement zone (5) and, then move the container (2) so as to place the foreign body (3) present outside the confinement zone (5). 4 - Method according to one of claims 1 to 3, characterized in that it consists in placing the foreign body (3) in a confinement zone (5) of the bottle such as the jable, the shoulder or the cap .

5 - Process according to claim 1, characterized in that it consists in taking images (Ii, I ₂ ) of the confinement zone (5) by revealing in the image part of the container.

6 - Process according to one of claims 1 to 4, characterized in that it consists in moving the container (2) so as to place the foreign body (3) present outside and in the confinement zone (5) in subjecting the container to tilting movements in the opposite direction.

7 - Installation for detecting inside a transparent or translucent container (2) containing a liquid, the presence of a foreign body (3) with a density greater than that of the liquid, the installation comprising:

means (4) for moving the container (2) so that it occupies a characteristic position in which a foreign body (3) present is placed outside an area of the containment vessel (5) of said foreign body,

means (4 ') for moving the container so that it occupies another characteristic position in which a foreign body present is placed in said confinement zone (5) of the container,

a first imaging system (10) adapted to take at least one image (I ₁ ) of the container confinement zone (5) when the latter occupies a characteristic position,

a second imaging system (20) adapted to take at least one image (I2) of the confinement zone of the container when the latter occupies its other characteristic position,

and a unit for processing and analyzing the images taken (Ii, I ₂ ) by the imaging systems (10, 20) in order to determine the presence or absence of a foreign body.

8 - Installation according to claim 7, characterized in that the means (4) for moving the container (2) so that it occupies a position feature are adapted to tilt the container relative to the vertical by a determined angle α while the means (4 ') for moving the container to occupy its other characteristic position are adapted to tilt the container relative to the vertical an angle (ai) of sign opposite to the determined angle α.

9 - Installation according to claim 7, characterized in that the imaging systems (10, 20) have viewing axes inclined relative to the longitudinal axis of the container at angles of equal values and opposite signs.

10 - Installation according to claim 7 or 9, characterized in that each imaging system (10, 20) comprises a camera (12, 22) and a light source (11, 21), placed on each side and other of the container, and adapted to detect defects by transmission.

11 - Installation according to claim 7, 9 or 10, characterized in that each imaging system (10, 20) comprises a camera (12, 22) and a light source (11, 21) adapted to detect defects by reflection.

12 - Installation according to claim 7 or 8, characterized in that the means (4, 4 ') for moving the container comprise a carousel rotating about a vertical axis and equipped with a series of gripping means (31) of radially distributed containers, the gripping means (31) being controlled in displacement so that on one turn, each container occupies its two characteristic positions in which a foreign body (3) present is placed in or out of the confinement zone ( 5).