Method for contactless in-line inspection of containers, and station for implementing same

Abstract

The invention relates to a method for in-line inspection of containers (2) each having a vertical axis and at least one external profile to be inspected, according to which method: - the measuring head (4) is configured to acquire, by optical projection, images of at least one external profile of each container, - for each movement cycle, the measuring head is positioned such that the axis of rotation of the measuring head is substantially coaxial to the vertical axis of the container as the measuring head is rotated in a circular movement, and the measuring head is moved linearly and parallel to the direction of translation so as to acquire images of the external profile over the entire periphery of the container.

Description

Description Title of the invention: Method for contactless online inspection of containers and station for its implementation Technical Field

[0001] The present invention relates to the technical field of the inspection of transparent or translucent containers, such as, for example, bottles, jars, flasks, ampoules or syringes made, for example, of glass or Polyethylene Terephthalate (PET).

[0002] The subject of the invention relates more specifically to the field of inspection of such containers, with a view to controlling or evaluating dimensional characteristics presented by these containers, such as measurements as well as detecting defects such as burrs or pimples.

[0003] The subject of the invention finds particularly advantageous applications, but not exclusively, for measuring the diameter of containers such as the external diameter of the ring or body of the containers or for detecting, on the ring of such containers, the presence of defects, in particular at the level of the horizontal mold joint. Prior art

[0004] In the field of container manufacturing, it is known to inspect the container neck to detect the presence of defects that may affect their aesthetic character or, more seriously, present a real danger to the user, such as burrs or spikes near the neck. It is also known to inspect the container neck to determine whether dimensional criteria are respected to ensure, in particular, correct capping and uncapping of the containers, the tightness of a capsule, a lid or a screw cap, in particular by the flatness of the neck surface, or the correct installation of a capsule or a screw cap depending on the geometry of the threads of the neck of the glass or PET container. The state of the art has proposed various optical inspection devices for containers.

[0005] For example, US patent 5,753,905 proposes an apparatus for inspecting the external characteristics of containers comprising a light source illuminating from one side of the container, the external profile of the container and to be recovered by a camera located on the other side of the container, an image of the profile of the container appearing in the form of a dark image on a light background. While the container is rotated on a revolution around its vertical axis, images are taken by the camera at each rotation increment in order to inspect the entire periphery of the container. This inspection apparatus has a rate limited by the handling of the container, which does not allow the containers to be inspected with the known manufacturing rates on container manufacturing lines.Indeed, inspection machines that handle rotating containers require a disruption of the translational transport flow on the conveyor, by transporting them to rotation and inspection stations, then putting them back on line on the conveyors. These automated mechanical operations limit the maximum throughput on the inspection lines. Furthermore, these machines that handle rotating containers must be adapted when changing the format of the inspected containers, which requires numerous manual operations, in particular the replacement of variable equipment for adapting the means of transport to the shape and dimensions of the series of containers to be produced. Finally, this equipment is very expensive to purchase and in terms of operating and maintenance costs.

[0006] In the state of the art, a method for measuring the wall thickness of containers moving in a row on a production line is known from DE 10 2019 121 835. This method is implemented using a measuring head which moves around a first container while this container moves linearly. During its movement around the container, the measuring head projects light onto the container in a direction or optical axis constantly orthogonal to the surface of the glass container and the light reflected specularly by the glass container is received by the measuring head. The wall thickness is measured by means of a non-contact optical measuring method which is determined on the basis of the light received by the measuring head. After going around the first container, the movement of the measuring head is repeated to repeat the measurement process on a second container which follows the first container in the line.

[0007] According to the embodiment described, the measuring head is moved using a pivoting arm robot. The solution described by this document has the advantage of being able to inspect the containers without stopping their linear movement in line. However, this document does not allow the diameter of the containers to be measured or the presence of defects on the ring of such containers to be detected. Furthermore, the kinematics of the measuring head is relatively complex to implement and does not allow the high movement rates of the containers, which can reach several hundred containers per minute, to be followed. Indeed, such a movement robot made up of different pivot axes leads to the creation of lever arms of large amplitudes and significant inertias in play.In the same sense, mounting the measuring head on the pivoting arm of a robot leads to problems of on-board mass, deformation and wear, making it difficult to industrially produce a reliable and economically viable measuring solution. In addition, to maintain the rates required for inspecting containers on production lines, the cost of a powerful and fast robot is high.

[0008] US 5,296,701 A discloses a method for inspecting containers in which a container is stopped, a head located above the container acquires the image of the mouth of said container by pivoting around it. Such a device is not satisfactory because it requires stopping the movement of the bottle, and does not allow the production of an external profile.

[0009] EP 3 597 549 A1, which relates to the more distant technical field of bottle processing during their filling, describes a system comprising a carousel on which bottles are placed with a predetermined spacing. A plurality of shuttles or mobile trolleys carrying a camera capable of testing the liquid filling level are arranged on a closed circuit and follow a bottle over a portion of the carousel. Such a device is not interesting because it requires perfect synchronization between the conveyors and the bottles. A Simply sliding a bottle onto a conventional conveyor would render the system unusable. Furthermore, such a system requires the use of a plurality of shuttles, and a plurality of sensors or cameras, and is not economical. Finally, such a system prevents the creation of an external profile. Statement of the invention

[0010] The present invention aims to overcome the drawbacks of the state of the art by proposing a method designed to inspect in-line the external profile of containers over their entire periphery using a safe and economically acceptable inspection technique while the containers have a high scrolling rate.

[0011] To achieve this objective, the method according to the invention aims to inspect in line containers each having a vertical axis and at least one external profile to be inspected, according to this method, the containers are moved in a conveying plane in a vertical position in a row in a translation direction to pass successively in an inspection station comprising a non-contact measuring head having an axis of rotation around which the measuring head is mounted to rotate, and the measuring head is moved according to successive movement cycles to successively inspect the containers during their translation in front of the inspection station, each movement cycle to inspect a container comprising an outward journey and a return journey and a rotation to inspect the entire periphery of the container. According to the method: - the measuring head is configured to acquire, by optical projection, images of at least one external profile of each container, - for each movement cycle, the measuring head is positioned so that the rotation axis is substantially coaxial with the vertical axis of the container when rotating the measuring head in a circular motion and to linearly move the measuring head parallel to the translation direction so as to acquire images of the external profile over the entire periphery of the container.

[0012] According to an exemplary implementation, the measuring head is configured to acquire, by optical projection, images of an external profile of each container and in that for each movement cycle, the measuring head is rotated over an angular range of at least 360° so as to acquire images of the external profile over the entire periphery of the container.

[0013] According to another example of implementation, the measuring head is configured to acquire, by optical projection, images of two diametrically opposed portions of an external profile of a container and in that for each movement cycle, the measuring head is rotated over an angular range of at least 180° so as to acquire images of the external profile over the entire periphery of the container.

[0014] Advantageously, for each movement cycle, the measuring head is rotated over a range of at least 180° on the outward path of the measuring head concomitantly with the linear movement of the measuring head, the measuring head being moved without rotation linearly on the return path.

[0015] Typically, for two successive displacement cycles of the measuring head in relation to two successive containers, the rotation of the measuring head is carried out in opposite directions.

[0016] According to a characteristic of the invention, the measuring head is configured to have an engagement volume for a container so that the vertical axis of the container can be substantially coaxial with the axis of rotation of the measuring head and a clearance volume so that the measuring head can be released from the container and the measuring head is moved to be engaged by its engagement volume, around the container, so that the axis of rotation of the measuring head is substantially coaxial with the vertical axis of the container and to be released from the container by its clearance volume.

[0017] According to an alternative embodiment, the measuring head is configured to comprise an image-taking system capable of delivering the image of at least a first external profile of the container in a first observation field and at least one lighting system illuminating the first observation field in the background of the first external profile and in that the image-taking system is driven during rotation of the measuring head to deliver images that contain a projection of the first external profile of the backlit container.

[0018] According to another variant embodiment, the measuring head is configured to comprise an image-taking system capable of delivering the image of at least a second external profile of the container, symmetrical to the first external profile relative to the vertical axis of the container, in a second observation field and at least one lighting system illuminating the second observation field in the background of the second external profile and the image-taking system is controlled during the rotation of the measuring head to deliver images which contain a projection of the second external profile of the backlit container.

[0019] Preferably, the method determines the position in the conveying plane of the vertical axis of each container moving in translation in the inspection station, and the movement of the measuring head is controlled so that the axis of rotation of the measuring head is substantially coaxial with the vertical axis of the container during the rotation of the measuring head.

[0020] Another object of the invention is to propose an in-line inspection station for containers each having a vertical axis and at least one external profile to be inspected and moved in a vertical position in line by a conveyor, in a translation direction to pass successively through the inspection station, the inspection station comprising: - a non-contact measuring head having an axis of rotation around which the measuring head is mounted to rotate in a circular motion, the measuring head comprising an image-taking system capable of delivering the image of at least a first external profile of the container in a first field of observation and at least one lighting system illuminating the first field of observation in the background of the first external profile, - a measuring head displacement structure configured to position the measuring head such that the rotation axis is substantially coaxial with the vertical axis of the container when the measuring head is rotated and to linearly move the measuring head parallel to the translation direction, - a control unit for the measuring head and the movement structure, receiving information from a system for determining the position in the plane of the conveyor, of the vertical axis of each container moving in translation in front of the inspection station, the control unit being configured to move the measuring head according to successive movement cycles to successively inspect the containers during their translation in the inspection station, each movement cycle for inspecting a container comprising an outward journey and a return journey and a rotation to inspect the entire periphery of the container, for each movement cycle, the movement structure positions the measuring head so that the rotation axis is substantially coaxial with the vertical axis of the container when the measuring head is rotated and linearly moves the measuring head parallel to the translation direction,the control unit controlling the image capture system so as to acquire images of the external profile over the entire periphery of the container during rotation of the measuring head.,

[0021] According to an exemplary embodiment, the structure for moving the measuring head comprises a motorized structure for linear movement of the measuring head in a direction parallel to the direction of translation, mounted on a moving assembly in a direction perpendicular to the direction of translation, the motorized structure being equipped with a supporting frame for the measuring head which comprises a support driven in rotation around the axis of rotation, by a motorization.

[0022] Typically, the measuring head is configured to have an engagement volume for a container so that the vertical axis of the container can be substantially coaxial with the axis of rotation of the measuring head and a clearance volume so that the measuring head can be cleared from the container.

[0023] For example, the measuring head is configured to have an engagement volume corresponding to the clearance volume or arranged to communicate with the clearance volume to constitute a volume passing through the support in the translation direction.

[0024] According to an alternative embodiment, the image capture system is capable of delivering the image of at least a second external profile of the container, symmetrical to the first external profile relative to the vertical axis of the container, in a second observation field and the lighting system illuminates the second observation field in the background of the second external profile and the image capture system is controlled during the rotation of the measuring head to deliver images which contain a projection of the profile of the second external profile of the backlit container.

[0025] For example, the imaging system comprises at least one camera observing the container directly or using at least one folding mirror.

[0026] Advantageously, the camera is mounted on the frame centered on the axis of rotation, observing the container using at least one folding mirror mounted on the support rotated about the axis of rotation.

[0027] According to another exemplary embodiment, the image capture system comprises at least one camera mounted on the support driven in rotation around the axis of rotation.

[0028] For example, the lighting system comprises at least one light source illuminating the container directly or using at least one folding mirror.

[0029] According to another example, the lighting system comprises at least one light source mounted on the support rotated about the axis of rotation. Brief description of the drawings

[0030] [Fig. 1] Figure 1 is a perspective view of a first exemplary embodiment of an inspection station according to the invention.

[0031] [Fig. 2] Figure 2 is an elevational view showing the inspection station of Figure 1 in a typical first stage.

[0032] [Fig. 2A] Figure 2A is a top view taken substantially along lines I1A of Figure 2.

[0033] [Fig. 2B] Figure 2B is a side view taken substantially along lines IIB of Figure 2.

[0034] [Fig. 2C] Figure 2C is an example of an image taken of a profile of a container, obtained with an inspection station according to Figure 1.

[0035] [Fig. 3] Figure 3 is an elevational view showing the inspection station of Figure 1 in a typical second stage of inspecting a container.

[0036] [Fig. 4] Figure 4 is an elevational view showing the inspection station of Figure 1 in a typical third stage of inspecting the container following in line the previously inspected container.

[0037] [Fig. 5] Figure 5 is a perspective view of a second exemplary embodiment of an inspection station according to the invention.

[0038] [Fig. 6] Figure 6 is an elevational view showing the inspection station of Figure 5 in a typical first stage of inspecting a container.

[0039] [Fig. 6A] Figure 6A is a top view taken substantially along lines VIA of Figure 6.

[0040] [Fig. 6B] Figure 6B is a side view taken substantially along lines VIB of Figure 6.

[0041] [Fig. 6C] Figure 6C is an example of an image taken of a profile of a container, obtained with an inspection station according to Figure 5.

[0042] [Fig. 7] Figure 7 is a top view showing the inspection station of Figure 5 in a typical second stage of inspecting a container.

[0043] [Fig. 8] Figure 8 is a top view showing the inspection station of Figure 5 in a characteristic third stage of inspecting the container next in line to the previously inspected container.

[0044] [Fig. 9] Figure 9 is a top view showing the inspection station of Figure 5 in a typical fourth inspection step.

[0045] [Fig. 10] Figure 10 is a top view showing the inspection station of Figure 5 in a typical fifth step of inspecting a container following in line the previously inspected container.

[0046] [Fig. 11] Figure 11 is a schematic top view showing an exemplary embodiment of a system for taking images of two opposite profiles of a container using a camera and folding mirrors.

[0047] [Fig. 12] Figure 12 is a schematic top view showing an exemplary embodiment of a system for taking images of two opposite profiles of a container using a camera without a folding mirror.

[0048] [Fig. 13] Figure 13 is a schematic top view showing an exemplary embodiment of a system for taking images of two opposite profiles of a container using two cameras without a folding mirror.

[0049] [Fig. 14A] Figure 14A is a schematic top view showing an exemplary embodiment of a measuring head in a position waiting to be engaged with a container.

[0050] [Fig. 14B] Figure 14B is a schematic top view showing an exemplary embodiment of a measuring head in a position in which a container is engaged in the measuring head.

[0051] [Fig. 14C] Figure 14C is a schematic top view showing an example of the embodiment of a measuring head in an intermediate position of rotation around the container for taking images.

[0052] [Fig. 14D] Figure 14D is a schematic top view showing an exemplary embodiment of a measuring head in a position in which the container disengages from the measuring head.

[0053] [Fig. 14E] Figure 14E is a schematic top view showing an exemplary embodiment of a measuring head in a position for which the measuring head is returned to its engagement waiting position for a new container.

[0054] [Fig. 15] Figure 15 is a sectional elevation view of an alternative embodiment of the measuring head in which the camera and the light source are mounted on the fixed part of the measuring head.

[0055] [Fig. 15A] Figure 15A is a sectional view taken substantially along lines XVA of Figure 15.

[0056] [Fig. 15B] Figure 15B is a sectional view taken substantially along lines XVB of Figure 15. Description of the embodiments

[0057] As can be seen from the drawings, the subject of the invention relates to a method and an inspection station 1 for automatically acquiring images of the external profile of containers 2 moving in scrolling motion at high speed. The invention relates to a so-called "on-line" control of containers, after a transformation or manufacturing step, in order to control the quality of the containers or of the transformation or manufacturing process.

[0058] The process operates for a flow rate of 2 containers. Ideally, inspection station 1 is capable of processing production at the production rate, for example 100 to 1000 containers per minute and typically around 500 containers per minute.

[0059] The invention provides a considerable improvement thanks to the inspection of containers in motion, avoiding the rotation of the containers which is not adapted to production rates because this method which involves a relative rotation of the containers in relation to the light sources and / or the sensors creates a "break in the motion" or a very slow movement of the containers.

[0060] In a known manner, the containers 2 which have just been formed by an installation of any type known per se, are taken over by a conveyor 3 to form a row of containers by being, in the example illustrated, placed successively in a vertical position on the conveyor. The containers 2 are transported in row by the conveyor 3 having a horizontal conveying plane defined by a longitudinal axis X parallel to the translation direction and by a transverse axis Y perpendicular to the translation direction. As shown in the drawings, the containers 2 are moved in row in a conveying plane X,Y, in a translation direction F parallel to the longitudinal axis X, and in a vertical position taken relative to a vertical axis Z perpendicular to the conveyor plane X, Y.

[0061] Advantageously, the containers 2 are containers made of transparent or translucent material such as, for example, bottles, jars, flasks, ampoules or syringes made of glass or PET. In the examples illustrated by the drawings, each container 2 has a bottom 2f resting on the conveyor 3 and from which rises along a vertical axis 2z, a vertical wall 2v ending in a so-called ring portion 2b. The ring 2b has a ring surface 2s, corresponding to the flat surface for sealing the container and a side wall 21, having, for example, reliefs adapted for gripping in the case of syringes or for attaching any container closure system, such as, for example, crimping a capsule, screwing a screw cap, holding a crimped collar or a wire cage, the various closure systems not being shown here but widely known.In the case of a container 2 of the bottle type, the vertical wall 2v has, from the bottom 2f, a part forming the body of the bottle which is connected to a neck 2c via a shoulder 2e. The vertical wall 2v is cylindrical, conical or of any cross-section such as square, rectangular or triangular or kidney-shaped as for flasks. An advantage of the ring inspection solution is that the method and the inspection station 1 according to the invention are suitable for all shapes of the body of the containers.

[0062] The containers 2 are transported by the conveyor 3 in order to transport them successively to different processing and inspection stations. As shown in the drawings, the containers 2 are moved in a vertical position in a row in the translation direction F to pass successively through the inspection station 1 according to the invention. The inspection station 1 is arranged in close proximity to the conveyor 3 in order to be able to inspect each container 2. The inspection station 1 is made in a fixed area limited in length relative to the length of the conveyor and in any appropriate location depending on the nature of the inspection to be carried out.

[0063] The inspection station 1 comprises a measuring head 4 configured to acquire, by optical projection and without contact, images of the external profile of the container over the entire periphery of each container 2 passing through the inspection station. The measuring head 4 has an axis of rotation a around which the measuring head 4 is mounted to rotate in a circular movement either in a clockwise direction shown diagrammatically by the arrow h or in a counterclockwise direction shown diagrammatically by the arrow ah. This measuring head 4 comprises an image-taking system 5 capable of delivering the image of at least a first external profile Pe of the container 2 in a first observation field Ç and at least one lighting system 6 illuminating the first observation field Ç in the background of the first external profile.

[0064] The external profile Pe of the container 2 corresponds to the contour of at least a portion of the container, taken in a plane passing through the vertical axis Z and perpendicular to the conveying plane XY. According to the example illustrated in Figure 2C, the image capture system 5 acquires an external profile Pe of the container 2 corresponding to one side of the ring 2b and a portion of the ring surface 2s of the container. According to the example illustrated in Figure 6C, the image capture system 5 acquires a first external profile Pe of the container 2 corresponding to one side of the ring 2b and a portion of the ring surface 2s of the container and a second external profile Pe of the container 2 corresponding to the symmetrical side of the ring 2b and a portion of the ring surface 2s of the container. Of course, the external profile Pe of the container 2 may correspond to other portions of the container such as the body of the container for example.

[0065] As will be described in detail in the remainder of the description, this measuring head 4 is mounted to rotate in order to inspect the entire periphery of the container 2. Images of the external profile Pe of the container are thus acquired during rotation at each increment step. The acquisition of images of the external profile Pe of the container 2 along its entire periphery by the measuring head 4 makes it possible to evaluate dimensional characteristics presented by these containers such as diameters of the ring or diameters of the body of these containers. It is also possible to detect defects such as defects on the ring of such containers, such as for the horizontal mold joint for example.

[0066] The image capture system 5 and the lighting system 6 are mounted in any suitable manner on the measuring head 4 to ensure, by optical projection, the acquisition of at least external profiles of the containers. According to an exemplary embodiment illustrated in FIGS. 2B and 6B, the measuring head 4 comprises a support 9 supported by a frame 11. The support 9 is driven in rotation relative to the frame 11, around the axis of rotation a, in both directions of rotation by a motorization 12 of any known type, such as an electric motor. The motorization 12 which is mounted on the frame 11, drives the support 9 in rotation, directly or by means of a mechanical transmission. The support 9 is guided in rotation in any suitable manner relative to the frame 11. In other words, the support 9 forms the part movable in rotation of the measuring head 4 relative to the frame 11 which forms the fixed part of the measuring head.

[0067] According to the exemplary embodiment illustrated in Figures 1, 2, 2A, 2B and 2C, the image capture system 5 is configured to deliver the image of a single first external profile of the container in a first single observation field and a lighting system 6 illuminates the first observation field Ç in the background of the first external profile. According to the exemplary embodiment illustrated in Figures 5, 6, 6A, 6B, 6C, and 7 to 13, the image capture system 5 is configured to deliver the image of a first external profile in a first observation field Ç and of a second external profile of the container, symmetrical to the first external profile with respect to the vertical axis a of the container, in a second observation field Ç. The lighting system 6 illuminates the first observation field in the background of the first external profile and illuminates the second observation field in the background of the second external profile.

[0068] The image capture system 5 comprises at least one camera 5a with its lens, observing the container 2 directly or using at least one folding mirror 5b. The lighting system 6 comprises at least one source of light 6a illuminating the container 2 directly or using at least one folding mirror 6b.

[0069] As illustrated in Figures 2A and 2B, the image capture system 5 comprises a camera 5a observing the container 2 using three folding mirrors 5b arranged between the camera 5a and the container. According to this example, these folding mirrors 5b each have a return angle of 45° relative to the axis of rotation a. According to this example, the camera 5a is mounted on the frame 11 while being centered on the axis of rotation a, and observing the container 2 using the folding mirrors 5b mounted on the support 9. Of course, each folding mirror 5b extends along the vertical axis Z at a height adapted to the height of the part of the container to be observed. For example, the support 9 is in the form of a disc extending from its lower face, by a structure extending along the vertical axis Z to allow the fixing of the folding mirrors 5b to convey the light to the camera.According to this example, the lighting system 6 comprises a light source 6a mounted on the support 9 to illuminate the field of observation of the camera 5a. The light source 6a is fixed on the underside of the support 9 in such a way that the light source 6a and a folding mirror 5a are located on either side of the container, tangentially illuminating an edge of the container 2 in order to be able to image the external profile of the container. Thus, the container 2 is positioned in the field of the camera 5a which can be direct or folded by folding mirrors 5b. The container 2 is positioned on the path of the light between a light source 6a and an image-taking camera 5a whose optical axis of observation, direct or folded by folding mirrors 5b, is positioned in such a way that the profile of the container is optically projected into an image with the source in the background.More precisely, the arrangement allows to visualize the profile projected in the image by light rays tangent to the edge of the container.

[0070] According to the embodiment illustrated in Figures 6A and 6B, the image capture system 5 comprises a camera 5a configured to observe the container 2 in two observation fields using folding mirrors 5b. According to this example, the camera 5a is mounted on the frame 11 while being centered on the axis of rotation a, and observing the container 2 using the folding mirrors 5b mounted on the support 9 to observe the first external profile and the second external profile of the container, symmetrical with respect to the vertical axis a. The lighting system 6 comprises two light sources 6a mounted on the support 9 to illuminate the two observation fields of the camera 5a. The light sources 6a are fixed on the lower face of the support 9 so that for each pair of light source 6a and folding mirror 5b, the light sources 6a and the folding mirrors 5b are located on either side of the container, tangentially illuminating the two edges of the container 2 in order to be able to image two symmetrical or diametrically opposite external profiles of the container.

[0071] In the examples described above, the camera 5a is mounted on the frame 11 so that the camera is fixed relative to the support 9 driven in rotation. According to another exemplary embodiment not illustrated, it should be noted that the camera 5a can be mounted on the support 9 driven in rotation about the axis of rotation. In this solution, the camera 5a is mounted directly on the support 9 in place of the folding mirror 5b or on the support 9 associated with a folding mirror 5b.

[0072] In the same sense, it should be noted that in the embodiment illustrated in Figures 6A and 6B, a single camera 5a observes the container 2 in two different observation fields Ç using two sets of folding mirrors 5b. The optical diagram of this assembly is illustrated in Figure 11. Of course, as illustrated in Figure 12, the image-taking system 5 may comprise a camera 5a directly observing the container 2 in an observation field Ç covering the two opposite sides of the container to image the two diametrically opposite external profiles of the container. Similarly, as illustrated in Figure 13, the image-taking system 5 may comprise two cameras 5a each directly observing the container 2 in two different observation fields Ç.

[0073] In the exemplary embodiments described in Figures 2A, 2B and 6A, 6B, the lighting system 6 comprises respectively one light source or two light sources 6a mounted on the support 9 driven in rotation around the axis of rotation. It should be noted as illustrated in Figure 11 that the two observation fields Ç can be illuminated by a single light source or as illustrated in Figure 12, by two light sources. Similarly, in the examples illustrated above, the container 2 is illuminated directly by the light source(s) 6a mounted on the support 9. Of course, the light source(s) can illuminate the container 2 using at least one reflector or folding mirror 6b fixed to the support 9.

[0074] Figures 15, 15A and 15B illustrate such an alternative embodiment for which the light source 6a is an annular light source fixed on the frame 11 and illuminating a folding mirror 6b fixed on the support 9 driven in rotation about the axis of rotation a. This lighting folding mirror 6b is positioned so as to reflect the light coming from a portion or an angular sector of the light source 6a located above it, this portion of the annular light source evolving during the rotation of the support 9. According to this exemplary embodiment, it is possible to provide that the light source 6a is controlled by independent sectors in order to illuminate only the sector located in vertical coincidence with the lighting folding mirror 6b. In Figure 15, the arrows indicate the direction of travel of the light.This illumination folding mirror 6b of the light is positioned to extend on one side of the container while a folding mirror 5b of the image taking system 5 is fixed to the support 9 to extend on the other side of the container 2 (figures 15 and 15A).

[0075] The image capture system 5 comprises two other folding mirrors 5b arranged between this first folding mirror 5b and the lens of the camera 5a fixed to the frame 11, with its optical axis coaxial with the axis of rotation a. These three folding mirrors 5b have for example an angle of 45° with the horizontal to bring the image of the profile of the container into the optical axis of the camera. It should be noted that the folding of the observation field Ç towards the camera 5a can be done with in all not three but two folding mirrors 5b having different angles with respect to the horizontal. Of course, the folding mirror(s) 5b folding 5b of the image capture system can be replaced by prisms, as can the lighting folding mirror(s) 6b. It should be noted that according to this embodiment variant, the light source 6a and the camera 5a are mounted on the chassis 11, i.e. on the fixed part of the measuring head 4. This solution avoids either the use of power or signal transmission cables between the fixed part (chassis 11) and the mobile part (support 9) of the measuring head or the use of signal and power transmission means without cables, such as rotating contact, optical and / or magnetic coupling between the fixed part (chassis 11) and the mobile part (support 9) of the measuring head.

[0076] According to another characteristic, the inspection station 1 comprises a displacement structure 15 of the measuring head 4, configured to position the measuring head 4 so that the rotation axis a is substantially coaxial with the vertical axis 2z of the container 2 when the measuring head is rotated and to linearly move the measuring head 4 parallel to the translation direction F. The chassis 11 of the measuring head 4 is therefore moved by the displacement structure 15 to position the rotation axis a of the support 9 substantially coaxial with the vertical axis 2z of the container 2. According to an exemplary embodiment, the displacement structure 15 of the measuring head 4 comprises a motorized structure 16 for linear displacement of the measuring head in a direction parallel to the translation direction F of the conveyor.This motorized structure 16 is equipped with the chassis 11 carrying the measuring head 4 so that the measuring head 4 can be moved linearly in both directions of the translation direction F. For example, this motorized structure 16 consists of a linear guide system which supports the measuring head 4. The linear guide is of any type, for example one or two rails on which slides the mobile chassis 11 mounted for example on bearings. The measuring head 4 or the mobile chassis 11 is pulled by a linear motor or by a toothed belt driven by a pinion motorized by a rotary motor.

[0077] It should be noted that the motorized structure 16 and the containers 2 may require relative alignment in the transverse direction Y, in order to maintain the axis of rotation a of the measuring head substantially coaxial with the vertical axis 2z of the containers 2. The relative alignment can be carried out as a function of the position in the transverse direction Y determined of each container in order to compensate for their variation in position in the transverse direction Y, or as a function of the position in the transverse direction Y determined of the part of each container examined (the ring for example) in order to compensate not only their variation in position in this direction but also the variations in verticality of each container. For this, a first solution consists of moving the motorized structure 16 in the transverse direction Y as a function of the determined position of each container or part of container examined. This motorized structure 16 is for example mounted on a movable assembly 17 in the transverse direction Y perpendicular to the translation direction F.The combination of the movements of the crew 17 and the motorized structure 16 makes it possible to position the measuring head 4 in any position in the conveying plane X, Y. An alternative to avoid the movement of the measuring head 4 in the transverse direction Y is to move the containers in the transverse direction Y before their entry into the inspection station 1 or during their transport in the station, by means of a motorized transverse centering system. However, it is also possible to avoid the movement of the measuring head 4 in the transverse direction Y if the field of observation of the image capture system 5 is wide and if the measuring head 4 has a large transverse capacity for receiving the containers.

[0078] According to an advantageous embodiment characteristic, the displacement structure 15 is configured so as to also be able to adjust the positioning of the measuring head 4 along the vertical axis Z. This adjustment possibility makes it possible to adapt the position of the measuring head 4 relative to the height of the containers 2 and to the area of ​​the containers to be inspected. This height adjustment is advantageously carried out before the actual inspection operation of a series of containers to be inspected generally having substantially identical heights. [0079JII It follows from the above description that the displacement structure 15 of the measuring head 4 is configured to be mounted overhanging the containers 2, that is to say the conveyor 3. The measuring head 4 is positioned above the containers so that the axis of rotation a can extend substantially coaxially with the vertical axis 2z of the container. However, in order to be able to image the external profile of the container, the image-taking system 5 and the lighting system 6 must be positioned on the sides of the container. Thus, the support 9 is positioned above the containers 2, extending towards the conveyor 3 so that the image-taking system 5 and the lighting system 6 can extend on either side of the sides of the container 2. It should be noted that the positioning along the vertical axis Z of the image-taking system 5 and the lighting system 6 depends on the area of ​​the profile of the container to be imaged.In the case where the external profile of the container to be imaged concerns the ring, the image-taking system 5 and the lighting system 6 are positioned at the ring of the container. In the case where the external profile of the container to be imaged concerns the body of the container, the image-taking system 5 and the lighting system 6 are positioned on either side of the body of the container 2. In this case, the support 9 extends along the vertical axis Z, over a greater height than in the case where the external profile of the ring is imaged in order to correctly position the image-taking system 5 and the lighting system 6 relative to the body of the container.

[0080] According to an advantageous characteristic, the measuring head 4 is maintained at the same altitude along the vertical axis Z during its movement for the inspection of the different containers 2. In other words, the measuring head 4 is positioned to be crossed by the containers 2 with the image capture system 5 and the lighting system 6 which extend on the sides of the container. It must be understood that the measuring head 4 is positioned on the path of movement of the containers, without modifying their rectilinear path. Each container 2 is therefore engaged laterally in the measuring head 4 which is moved in the inspection station 1 to follow the movement of movement of the container.

[0081] The measuring head 4 and more precisely, the support 9 is configured to have an engagement volume Ve for a container 2 so that the vertical axis 2z of the container can be substantially coaxial with the rotation axis a of the measuring head 4 and a clearance volume Vd in order to be able to disengage the measuring head 4 from the container. This engagement volume and this clearance volume which correspond to free volumes, are defined between the image capture system 5 and the lighting system 6 to allow the container to be positioned so that the rotation axis a of the measuring head 4 is coaxial with the vertical axis of the container 2.

[0082] In the examples illustrated in Figures 2B and 6B, the support 9 is configured to have an engagement volume Ve arranged to communicate with the clearance volume Vd to constitute a volume passing through the support 9 in the translation direction. Thus, the measuring head 4 can be engaged by its through volume around a container 2. During the rotation of the measuring head 4 and its linear movement, the container remains engaged in this volume. For the release of the container, the support 9 is positioned so that the clearance volume is oriented in the translation direction.

[0083] Figures 14A to 14E illustrate another variant embodiment for which the support 9 is configured to have an engagement volume Ve corresponding to the clearance volume Vd. It should be noted that the engagement volume and the clearance volume can be made through by removing the part of the support 9 located between the lines 9a (figure 14A).

[0084] According to another characteristic of the invention, the inspection station 1 comprises a system 19 for determining the position along at least the translation direction X of the vertical axis 2z of each container moving in translation in the inspection station 1. In practice, according to an exemplary implementation, this determination system 19 is configured to determine the position of the vertical axis 2z of each container along the translation direction X, prior to the entry of the containers 2 into the inspection station and considers that the translation speed of the containers is constant between the occurrence of detection and the passage into the inspection station. It should be noted that this determination system 19 can take into account the position along the longitudinal axis X of each container during all or part of its journey in the inspection station.

[0085] This determination system 19 is necessarily configured to know the position of the containers 2 in the translation direction X but it can be configured to also determine the position in the transverse direction Y. The determination system 19 can determine at least the position in the translation direction X, or even the position in the conveying plane X and Y of each container (or their ring), several times or continuously during their journey in the inspection station 1. The position in the translation direction X or in the conveying plane X, Y can also be obtained directly by the measuring head 4 and the analysis of the images taken of the container.Indeed, on the one hand the position of the measuring head 4 in rotation around the axis of rotation a and in translation along the direction of translation X is known and on the other hand, the position of each container (or its ring) in the field of observation is also known, from a profile taking into account the nominal diameter of the container at this height, or even more precisely when the measuring head observes two opposite profiles at the same time, the axis of the container being able to be located in the images as the middle of the two profiles. It is possible to combine several location systems, such as a light barrier system to control the placement, at the entrance to the inspection station, of the container in the field of observation, then the maintenance of the axis of rotation a coaxial with the axis of the container during the journey in the inspection station.

[0086] This determination system 19 can be implemented in any appropriate manner, for example using a system taking into account the speed of the conveyor 3 and one or two cells (optical barriers) or at least one camera for taking images of the containers before they enter the inspection station 1. This determination system 19 thus makes it possible to know the position in the conveying plane, of the vertical axis 2z of each container during its movement in the inspection station 1.

[0087] According to another characteristic of the invention, the inspection station 1 comprises a control unit 21 for the measuring head 4 and the movement structure 15, receiving the information from the system 19 for determining the position of the vertical axis 2z of each container 2. This control unit 21 is configured to move the measuring head 4 according to successive movement cycles to inspect, without contact, the containers successively during their translational passage in the inspection station 1. Each movement cycle for inspecting a container 2 comprises an outward path with rotation to inspect the entire periphery of the container and a return path. For each movement cycle, the control unit 21 controls the movement structure 15 to position the measuring head 4 so that the rotation axis a is substantially coaxial with the vertical axis 2z of the container when the measuring head 4 is rotated.The control unit 21 controls the operation of the motorization 12 to rotate the measuring head 4 and the displacement structure 15 to simultaneously move the measuring head parallel to the translation direction F while keeping the rotation axis a substantially coaxial with the vertical axis 2z of the container. The control unit 21 controls the image capture system 5 so as to acquire images of the external profile over the entire periphery of the container during the rotation of the measuring head 4.

[0088] This control unit 21 is made in any suitable manner to move the measuring head 4 and acquire images over the entire periphery of each container 2. The control unit 21 comprises units of the axis card type or power variators in order to control the rotary and / or linear motors. This control unit 21 is also an electronic information processing unit implementing a computer system of any type comprising computers, external peripherals (display unit, storage unit, keyboards, connection to different factory networks, etc.), programs, databases, etc. The images taken by the cameras are analyzed in order to ensure quality control, in particular to control or evaluate dimensional characteristics of the containers and / or to observe or analyze defects in the containers.

[0089] Inspection station 1 as described above allows the implementation of an online container inspection method which follows directly from the preceding description.

[0090] According to such a method, the containers 2 are moved in a vertical position in a row in the translation direction F to pass successively through the inspection station 1 according to the invention comprising the measuring head 4. The method according to the invention aims to move the measuring head 4 according to successive movement cycles to inspect, without contact, the containers 2 successively during their translation in the inspection station. It must be understood that the inspection of the containers 2 is carried out without modifying the translational movement of the containers imposed by the conveyor 3.

[0091] By definition, each movement cycle of the measuring head 4 aims to inspect, without contact, a container 2 driven in translation by the conveyor 3. Each movement cycle for inspecting a container 2 comprises an outward journey with rotation of the measuring head to inspect the entire periphery of the container and a return journey. In order to position the measuring head 4 relative to each container 2 moving in the inspection station 1, the method according to the invention determines the position in the translation direction F of the vertical axis 2z of each container 2 moving in translation in the inspection station. For this purpose, the control unit 21 receives the information from the system 19 which determines at least the position in the translation direction F of the vertical axis 2z of each container 2.The control unit 21 controls the movement of the measuring head 4 so that the rotation axis a of the measuring head 4 is substantially coaxial with the vertical axis 2z of the container when the measuring head rotates. Furthermore, it should be noted that the control unit 21 controls the movement of the measuring head 4 and in particular the motorization 12 so that the engagement volume Ve of the measuring head is positioned to allow the engagement of the measuring head around the container 2 so that the vertical axis 2z of the container can be substantially coaxial with the rotation axis a of the measuring head.

[0092] During the forward travel, the measuring head 4 is moved to follow the translational movement of the container 2. The measuring head 4 is moved parallel to the translational direction F. The control unit 21 controls the displacement structure 15 and more precisely the motorized linear displacement structure 16 in the direction F1, in the same direction as the direction of movement of the container. During the forward travel, the measuring head is positioned so that the rotation axis a of the measuring head 4 is substantially coaxial with the vertical axis 2z of the container when the measuring head is rotated. Substantially coaxial means that at a minimum, the control unit 21 controls the displacement structure 15 as a function of the position of the container so that the analyzed profile(s) remain in the field of observation of the measuring head 4.When the determination system 19 determines at least the position in the translation direction (longitudinal axis X) of each container or their ring, several times or continuously during their journey in the inspection station, then the control unit 21 controls the movement structure 15 and more precisely the motorized linear movement structure 16 to maintain by servo-control, the rotation axis a of the measuring head 4 substantially coaxial with the vertical axis 2z of the container during their journey in the inspection station 1.

[0093] It may be provided that the control unit 21 controls the movement structure 15 and in particular the mobile assembly 17 as a function of the position of the container along the transverse axis Y. The combination of the movements of the measuring head 4 along the X, Y axes allows the measuring head to have its rotation axis a coaxial with the vertical axis 2z of the container. It may also be provided that the same control unit 21 also controls a motorized member for transverse centering of the containers as explained previously, before their entry into the inspection station 1 or during their transport into the inspection station 1.

[0094] During the outward journey, the measuring head 4 is controlled in rotation to inspect the entire periphery of the container 2 while the axis of rotation a of the measuring head remains substantially coaxial with the vertical axis 2z of the container. It is recalled that the measuring head 4 is moved in translation so that the rotation axis a of the measuring head remains substantially coaxial with the vertical axis 2z of the container. The control unit 21 controls the motorization 12 to rotate the measuring head 4 while the measuring head is moved in translation. Simultaneously, the control unit 21 controls the camera(s) 5a as well as possibly the light source(s) 6a if the latter are controlled to illuminate according to a flash or pulse mode only during the image acquisition phase.

[0095] According to the invention, the measuring head 4 is configured to acquire, by optical projection, images of at least one external profile of each container 2. Also, for the acquisition of the profile images, the control unit 21 controls the camera(s) 5a so that at each rotation increment of the container, an image is taken so that the number of images per rotation revolution is greater than, for example, 36. In other words, the method aims to acquire at least one image every 10° of rotation of the container 2. For example, the number of images of a container 2 over 360° is between 36 and 96 or even 360. The rotation increment of the container between each image taken represents an angular sector traveled by the container ranging, for example, from 10° to less than 3.75° or even 1°.Limitations on the number of images are related to optoelectronics (maximum video frequency of the camera, sensitivity of the sensor), the maximum light intensity of the light source, usually an LED source, and the volume of data that can be transferred, stored and analyzed (memory capacity, transmission speed and computing power of the processors).

[0096] The outward path of an inspection cycle of a container 2 is followed by a return path for which the measuring head 4 is returned to a position suitable for inspecting the container which follows in the line.

[0097] At the end of the outward journey, it should be noted that the control unit 21 controls the movement of the measuring head 4 and in particular the motorization 12 so that the clearance volume Vd of the measuring head is positioned to allow the clearance of the measuring head relative to the container 2 in order that the container can continue its movement. For the return journey, the control unit 21 controls the movement structure 15 and more precisely the motorized linear movement structure 16 in the direction F2, opposite to the direction of movement of the containers. It should be noted that during most of the return journey, no container is present in the inspection station 1.

[0098] The control unit 21 optionally controls the moving assembly 17 so as to anticipate the positioning of the measuring head 4 relative to the next container to be inspected. At the end of the return journey, the measuring head 4 is returned, for example, substantially to its initial position that it had at the start of the movement cycle. The control unit 21 controls the movement of the measuring head 4 to carry out a new inspection cycle for the container that follows in the queue.

[0099] Figures 1, 2, 2A, 2B and 2C illustrate a first example of implementation of the inspection method according to the invention for which the image capture system 5 is configured to deliver the image of a single external profile of the container in an observation field illuminated in the background of the external profile by the lighting system 6. According to this example of embodiment, for each movement cycle, the measuring head 4 is rotated over an angular range of at least 360° so as to acquire images of the external profile over the entire periphery of the container 2.

[0100] For a movement cycle for inspecting a container 2, the control unit 21, which receives the information from the system 19, controls the movement of the measuring head 4 and in particular the motorization 12 so that the engagement volume Ve of the measuring head is positioned to allow the engagement of the measuring head around the container 2 (figure 2, 2A). After positioning the measuring head so that the rotation axis a of the measuring head 4 is substantially coaxial with the vertical axis 2z of the container, the control unit 21 controls the motorized linear movement structure 16 in the direction Fl, and also controls the motorization 12 to rotate the measuring head 4 through at least 360° and 380° for example. Simultaneously, the control unit 21 controls the motorized linear movement structure 16 in the direction Fl, and also controls the motorization 12 to rotate the measuring head 4 through at least 360° and 380° for example. Simultaneously, the control unit 21 controls the motorized linear movement structure 16 in the direction Fl, and also controls the motorization 12 to rotate the measuring head 4 through at least 360° and 380° for example. command 21 controls the camera 5a as well as the light source to acquire profile images over the entire periphery of the container (figure 3).

[0101] At the end of the outward journey, the control unit 21 controls the movement of the measuring head 4 and in particular the motorization 12 so that the clearance volume Vd of the measuring head is positioned to allow the clearance of the measuring head with respect to the container 2. The control unit 21 controls the movement structure 15 for the return journey of the measuring head 4 in order to bring it back into a position allowing it to carry out a new inspection cycle for the container which follows in the queue (figure 4).

[0102] Figures 5, 6, 6A, 6B, 6C, and 7 to 10 illustrate a second example of implementation of the inspection method according to the invention for which the image capture system 5 is configured to deliver the image of a first external profile in a first field of observation and of a second external profile of the container, symmetrical to the first external profile with respect to the vertical axis 2z of the container, in a second field of observation. As is apparent from Figure 6C, this example makes it possible to acquire the two symmetrical external profiles of a ring for example. It should be noted that this example also makes it possible to acquire the internal profile of the ring allowing dimension measurements on the internal diameter of the mouth of the container.

[0103] According to this preferred example, the measuring head 4 is rotated over an angular range of at least 180° so as to acquire images of the external profile over the entire periphery of the container. Advantageously, the control unit 21 controls the motorization 12 to rotate the measuring head 4 over an angular range of between 180° and 220°. In comparison with a method in which the rotation of the measuring head 4 is 380°, this method allows a faster inspection, since at identical transport and rotation speeds, the length of the inspection station 1 is halved, and / or more stable with an identical translation speed and distance but a rotation speed halved, and / or also more resolved since with identical translation speed and distance, a speed of rotation divided by two, it is possible to take images spaced by a rotation increment divided by two.

[0104] For a movement cycle for inspecting a container 2, the control unit 21, which has received the information from the system 19, controls the movement of the measuring head 4 and in particular the motorization 12 so that the engagement volume Ve of the measuring head is positioned to allow the engagement of the measuring head around the container 2 (Figure 6A). After positioning the measuring head so that the rotation axis a of the measuring head 4 is substantially coaxial with the vertical axis 2z of the container, the control unit 21 controls the motorized linear movement structure 16 in the direction Fl, and also controls the motorization 12 to rotate the measuring head 4 through 220°, for example, in the clockwise direction h. Simultaneously, the control unit 21 controls the camera 5a as well as the light sources 6a to acquire profile images over the entire periphery of the container (Figure 7).

[0105] At the end of the outward journey, the control unit 21 controls the movement of the measuring head 4 and in particular the motorization 12 so that the clearance volume Vd of the measuring head is positioned to allow the clearance of the measuring head with respect to the container 2. The control unit 21 controls the movement structure 15 for the return journey of the measuring head 4 in order to position the measuring head ready to carry out a new inspection cycle for the container which follows in the queue (figure 8). It should be noted that in the case where the measuring head 4 has a through engagement and clearance volume, the measuring head 4 is oriented when a container leaves in a good position to receive a new container. In other words, the measuring head 4 maintains its orientation between the position where a container leaves the measuring head and the position where a new container engages in the measuring head (figures 7 and 8).Thus, during the return journey, the measuring head 4 is in simple translation, without rotation, whatever the amplitude of rotation on the outward journey. It should be noted that a measuring head 4 having a through engagement and disengagement volume has another advantage when it is broken down or stopped since the measuring head does not. does not block the translational scrolling of the containers. A measuring head 4 having a through volume for the engagement volume and the release volume and a rotation limited to 180° constitutes a preferred embodiment variant.

[0106] The measuring head 4 is then able to inspect the container that follows in the line. For this new movement cycle in order to inspect this container 2, the control unit 21 which has received the information from the system 19, controls the measuring head so that the rotation axis a of the measuring head 4 is substantially coaxial with the vertical axis 2z of the container. The control unit 21 controls the movement structure 15 in particular the motorized linear movement structure 16 in the direction F1, and also controls the motorization 12 to rotate the measuring head 4 through 220° for example, in the counterclockwise direction ah. Simultaneously, the control unit 21 controls the camera 5a as well as the light sources 6a to acquire profile images over the entire periphery of the container (figure 9).

[0107] At the end of the outward journey, the control unit 21 controls the movement structure 15 for the return journey of the measuring head 4 in order to position the measuring head ready to carry out a new inspection cycle for the container which follows in the queue (figure 10).

[0108] It is clear from this example of implementation for each movement cycle that the measuring head 4 is rotated over a range of at least 180° on the outward path of the measuring head 4 concomitantly with the linear movement of the measuring head while the measuring head 4 is moved linearly without rotation on the return path. Thus, for two successive movement cycles of the measuring head 4 in relation to two successive containers in the line, the rotation of the measuring head 4 is carried out in opposite directions. The alternating direction rotation of the measuring head 4 offers the advantage of being able to control the winding of the power cables of the measuring head 4 when the light source and / or the camera is / are integral with the rotating support 9. Obviously, the problem of winding and unwinding cables does not exist if the light source and the camera are fixed. with respect to the chassis 11 (figure 15) or if means of transmitting signals and energy without cable are used, such as rotating contact, optical and / or magnetic coupling between the light sources or camera on board the rotating support 9 and the chassis 11. An example of a rotating contact cable is a connector for coaxial cable used to power and control a camera according to the communication standard known as CoaXPress®.

[0109] Figures 14A to 14E illustrate a third example of implementation of the inspection method according to the invention for which the measuring head 4 is configured to have an engagement volume Ve corresponding to the clearance volume Vd. Figure 14A illustrates the positioning of the engagement volume on the path of the container 2 to be inspected. In this position, the container 2 can penetrate into the measuring head 4 so that the light source 6a and the folding mirror 5b are located on either side of the container (figure 14B).

[0110] For a movement cycle for inspecting this container 2, the control unit 21 which has received the information from the system 19, controls the movement structure 15 so that the rotation axis a of the measuring head 4 is substantially coaxial with the vertical axis 2z of the container. The control unit 21 controls the motorized linear movement structure 16 in the direction F1, and simultaneously also controls the motorization 12 to rotate the measuring head 4 through 180° to acquire two symmetrical external profiles or 380° for example in the counterclockwise direction ah (figures 14C and 14D). Simultaneously, the control unit 21 controls the camera 5a as well as the light source to acquire profile images over the entire periphery of the container during the rotation of the measuring head.

[0111] At the end of the outward journey, the clearance volume Vd of the measuring head is positioned to allow the clearance of the measuring head relative to the container 2. The control unit 21 controls the motorized linear displacement structure 16 in the direction F2 in order to return the measuring head to a position allowing it to carry out a new inspection cycle for the container which follows in the line. Furthermore, the control unit 21 controls the motorization 12 in the clockwise direction h so that the engagement volume Vd of the measuring head is positioned to allow the engagement of the measuring head with respect to a new container 2 (figure 14E).

[0112] It follows from this embodiment variant for which the engagement volume Ve corresponds to the clearance volume Vd that the measuring head must be rotated during the return journey in order to return the engagement volume Ve to the arrival side of the next container. Furthermore, if cables exist between the frame 11 and the support 9 because of the mounting of the light sources and the cameras, the rotation of the support 9 during the return journey is in the opposite direction to the rotation of the support 9 during the outward journey. It should be noted that the rotation during the return journey can be arbitrary if the cameras and the light sources are fixed on the frame 11 using deflecting mirrors or if the energy and signal transmissions are carried out by means of rotating contacts (mainly power), optical couplings (signals only) or magnetic couplings.

[0113] The preferred variant aims to avoid rotating the measuring head during the return trip. This preferred variant without rotation on the return trip is much faster, because during the return trip there is no need to control the rotation, and there is no Coriolis effect. For example, the return trip is carried out at a translation speed 30% higher than that of the outward trip. This return trip in simple translation is possible in the following cases: - the rotation on the outward journey is approximately 360°, whether the engagement volumes Ve or clearance volumes Vd are through or not, - the engagement volumes Ve and clearance volumes Vd constitute a through volume, whether the rotation is 180° or 360°.

[0114] In other words, the return path with rotation is only necessary if the measuring head does not have through engagement and clearance volumes and if the rotation is limited to 180° (Figures 14A to 14E).

[0115] It should also be noted that the control laws for translational movements during the outward journey, and in particular accelerations, are such that at the start of the outward journey, in a stalling or station entry phase, we bring quickly but gradually the axis of rotation a coincides with the vertical axis 2z of the containers, the axis a being during the setting phase, either ahead or behind the vertical axis 2z. The same reasoning applies in an exit phase from the inspection station, therefore at the end of the outward journey and at the beginning of the return journey.

Claims

Claims

1. Method for in-line inspection of containers (2) each having a vertical axis (2z) and at least one external profile to be inspected, according to the method, the containers are moved in a conveying plane (X, Y), in a vertical position in a line in a translation direction to pass successively in an inspection station comprising a contactless measuring head (4) having an axis of rotation (a) around which the measuring head is mounted to rotate, and the measuring head is moved according to successive movement cycles to successively inspect the containers during their translation in front of the inspection station, each movement cycle to inspect a container comprising an outward journey and a return journey and a rotation to inspect the entire periphery of the container, characterized in that it consists: - to configure the measuring head (4) to acquire by optical projection, images of at least one external profile of each container, - for each movement cycle, positioning the measuring head (4) so ​​that the rotation axis (a) is substantially coaxial with the vertical axis (2z) of the container when rotating the measuring head in a circular motion and linearly moving the measuring head parallel to the translation direction so as to acquire images of the external profile over the entire periphery of the container.

2. Method according to claim 1 according to which the measuring head (4) is configured to acquire by optical projection, images of an external profile of each container and in that for each movement cycle, the measuring head is rotated over an angular range of at least 360° so as to acquire images of the external profile over the entire periphery of the container.

3. Method according to claim 1 according to which the measuring head (4) is configured to acquire by optical projection, images of two diametrically opposed portions of an external profile of a container and in that for each movement cycle, the measuring head is rotated over an angular range of at least 180° so as to acquire images of the external profile over the entire periphery of the container.

4. Method according to the preceding claim, wherein for each movement cycle, the measuring head is rotated over a range of at least 180° on the outward path of the measuring head concomitantly with the linear movement of the measuring head, the measuring head being moved without rotation linearly on the return path.

5. Method according to one of the preceding claims, wherein for two successive displacement cycles of the measuring head in relation to two successive containers, the rotation of the measuring head is carried out in opposite directions.

6. Method according to one of the preceding claims, wherein the measuring head (4) is configured to have an engagement volume (Ve) for a container so that the vertical axis (2z) of the container can be substantially coaxial with the axis of rotation (a) of the measuring head and a clearance volume (Vd) so as to be able to disengage the measuring head from the container and in that the measuring head (4) is moved to be engaged by its engagement volume, around the container, so that the axis of rotation of the measuring head is substantially coaxial with the vertical axis of the container and to be disengaged from the container by its clearance volume.

7. Method according to one of the preceding claims, according to which the measuring head (4) is configured to comprise an image-taking system (5) capable of delivering the image of at least a first external profile of the container in a first observation field and at least one lighting system (6) illuminating the first observation field in the background of the first external profile and in that the image-taking system (5) is controlled during the rotation of the measuring head to deliver images which contain a projection of the first external profile of the backlit container.

8. Method according to the preceding claim according to which the measuring head (4) is configured to comprise a gripping system image capture system (5) capable of delivering the image of at least a second external profile of the container, symmetrical to the first external profile with respect to the vertical axis of the container, in a second field of observation and at least one lighting system (6) illuminating the second field of observation in the background of the second external profile and in that the image capture system is controlled during the rotation of the measuring head to deliver images which contain a projection of the second external profile of the backlit container.

9. Method according to one of the preceding claims, in which the position in the conveying plane (X, Y) of the vertical axis (2z) of each container moving in translation in the inspection station is determined, and in that the movement of the measuring head (4) is controlled so that the axis of rotation of the measuring head is substantially coaxial with the vertical axis of the container during the rotation of the measuring head.

10. In-line inspection station for containers each having a vertical axis (2z) and at least one external profile to be inspected and moved in a vertical position in line by a conveyor (3), in a translation direction to move successively through the inspection station, the inspection station comprising: - a contactless measuring head (4) having an axis of rotation (a) around which the measuring head is mounted to rotate in a circular motion, the measuring head comprising an image-taking system (5) capable of delivering the image of at least a first external profile of the container in a first field of observation and at least one lighting system (6) illuminating the first field of observation in the background of the first external profile, - a displacement structure (15) of the measuring head (4) configured to position the measuring head so that the rotation axis is substantially coaxial with the vertical axis of the container when the measuring head is rotated and to linearly move the measuring head parallel to the translation direction, - a control unit (21) of the measuring head (4) and of the structure of movement (15), receiving information from a system (19) for determining the position in the plane of the conveyor, of the vertical axis of each container moving in translation in front of the inspection station, the control unit (21) being configured to move the measuring head according to successive movement cycles to successively inspect the containers during their translation in the inspection station, each movement cycle for inspecting a container comprising an outward journey and a return journey and a rotation to inspect the entire periphery of the container, for each movement cycle, the movement structure positions the measuring head so that the rotation axis is substantially coaxial with the vertical axis of the container when the measuring head is rotated and linearly moves the measuring head parallel to the translation direction,the control unit controlling the image capture system so as to acquire images of the external profile over the entire periphery of the container during rotation of the measuring head.,

11. Inspection station according to claim 10 according to which the displacement structure (15) of the measuring head comprises a motorized structure (16) for linear displacement of the measuring head in a direction parallel to the direction of translation, mounted on a mobile assembly (17) in a direction perpendicular to the direction of translation, the motorized structure (16) being equipped with a chassis (11) carrying the measuring head which comprises a support (9) driven in rotation around the axis of rotation, by a motorization (12).

12. Inspection station according to claim 11 according to which the measuring head (4) is configured to have an engagement volume (Ve) for a container so that the vertical axis of the container can be substantially coaxial with the axis of rotation of the measuring head and a clearance volume (Vd) so that the measuring head can be released from the container.

13. Inspection station according to claim 12 according to which the measuring head (4) is configured to have an engagement volume corresponding to the clearance volume or arranged to communicate with the clearance volume to constitute a volume crossing the support in the translation direction.

14. Inspection station according to one of claims 10 to 13 according to which the image capture system (5) is capable of delivering the image of at least a second external profile of the container, symmetrical to the first external profile with respect to the vertical axis of the container, in a second field of observation and the lighting system (6) illuminates the second field of observation in the background of the second external profile and in that the image capture system is controlled during the rotation of the measuring head to deliver images which contain a projection of the profile of the second external profile of the backlit container.

15. Inspection station according to one of claims 10 to 14, according to which the image-taking system (5) comprises at least one camera (5a) observing the container directly or using at least one folding mirror (5b).

16. An inspection station according to claim 15 wherein the camera (5a) is mounted on the frame (11) centered on the axis of rotation, observing the container using at least one folding mirror (5b) mounted on the support (9) rotated about the axis of rotation.

17. Inspection station according to claim 15 according to which the image capture system (5) comprises at least one camera (5a) mounted on the support (9) driven in rotation around the axis of rotation.

18. Inspection station according to one of claims 10 to 17, wherein the lighting system (6) comprises at least one light source (6a) illuminating the container directly or using at least one folding mirror (6b).

19. Inspection station according to claim 18 according to which the lighting system (6) comprises at least one light source (6a) mounted on the support driven in rotation around the axis of rotation.

Images