Imaging device for a container inspection device

Abstract

Imaging device for a container inspection device The imaging device (1) comprises an image acquisition device (4) oriented towards a semi-reflecting plate (20) and a light source (6) oriented towards said semi-reflecting plate (20) extending in an internal volume (18) of a housing (8) comprising an acquisition opening (22). The housing (8) comprises a mounting opening (24) for the image acquisition device (4) and a receiving opening (34) for the light source (6), the internal volume (18) of the housing (8) being sealed by a window (40) extending into the acquisition opening (22), by the image acquisition device (4) and by the light source (6). Figure for abstract: figure3

Description

Title of the invention: Imaging device for a container inspection device

[0001] The present invention relates to an imaging device for a container inspection device, of the type comprising an image acquisition device oriented towards a semi-reflecting plate and a light source oriented towards said semi-reflecting plate, said semi-reflecting plate being arranged to align the direction of shooting of the images of the image acquisition device and the direction of the light emitted by the light source in an axial direction, said semi-reflecting plate extending in an internal volume of a housing comprising an acquisition opening extending in the axial direction.

[0002] The invention also relates to a device for inspecting at least one container comprising such an imaging device.

[0003] The invention applies to any type of container, in particular to a preform or a finished container made from such a preform.

[0004] A preform makes it possible to produce a finished container by blowing the preheated preform. Such a preform comprises a body which is deformed during blowing and a neck which is already molded to its final shape and which remains unchanged during blowing.

[0005] To produce quality finished containers, it is important to ensure that the preforms used have satisfactory parameters before they are deformed. Thus, it is known to inspect the preforms before they are introduced into the molds of a blowing wheel in which the preforms are formed into containers by blowing.

[0006] The inspection is carried out, for example, from images of each preform acquired and analyzed by an image processing device.

[0007] More particularly, an imaging device is for example provided to obtain one or more images of the collar and / or the rim of a preform, for example to detect the presence of a defect in the collar and / or the rim and / or to detect the angular orientation of the preform.

[0008] In order to obtain images of satisfactory quality to ensure these detections, the collar and / or the rim must be illuminated with light emitted in a direction aligned with the shooting direction of an image acquisition device, this direction corresponding for example to the axis of the preform whose collar and / or rim are inspected. For this purpose, it is for example provided to arrange the image acquisition device and a light source on either side of a blade semi-reflective arranged to align the emitted light and the shooting direction.

[0009] However, such an arrangement is likely to become soiled, fogged and / or exposed to liquids, particularly when used in a container production facility, which degrades the quality of the acquired images and may prevent effective inspection of the preform collar.

[0010] One of the aims of the invention is to overcome these drawbacks by proposing an imaging device making it possible to illuminate a container in the same direction as the shooting direction and protected from the external environment.

[0011] To this end, the invention relates to an imaging device of the aforementioned type, in which the housing comprises an opening for mounting the image acquisition device, said image acquisition device being mounted in a sealed manner on said mounting opening from outside the internal volume, and an opening for receiving the light source, the light source being received in a sealed manner by said receiving opening from outside the internal volume, the internal volume of the housing being closed in a sealed manner by a window extending into the acquisition opening, by the image acquisition device and by the light source.

[0012] By providing a housing sealed by the image acquisition device, the light source and a window, the various elements of the imaging device, in particular the semi-reflecting plate, are protected from the external environment of the imaging device, which ensures satisfactory quality of the acquired images. Furthermore, by mounting the image acquisition device and arranging the light source on corresponding openings of the housing, these elements remain accessible from outside the housing, which allows maintenance operations to be carried out simply and quickly. Finally, the imaging device forms a compact and manipulable module in a single piece, which makes it simple to implement in a container production facility.

[0013] The imaging device according to the invention may comprise one or more of the following characteristics, taken in isolation or in any technically conceivable combination: - the semi-reflecting plate is arranged to transmit the images to the image acquisition device in the axial direction and to reflect the light emitted by the light source in the axial direction, - the semi-reflecting plate is arranged to transmit the light emitted by the light source in the axial direction and to reflect the images towards the image acquisition device, - the image acquisition device comprises a lens extending into the internal volume of the housing and said lens being mounted on an acquisition unit extending to the exterior of the internal volume, - the housing comprises a maintenance opening extending opposite the semi-reflecting blade, said maintenance opening being closed in a sealed and reversible manner by a cover, - the housing comprises an internal wall delimiting the internal volume, said internal wall being made of or coated with a non-reflective material, - the internal wall comprises curved and / or textured sections at least around the acquisition opening, the mounting opening and the receiving opening, - the acquisition opening extends between a first end opening into the internal volume and a second end opening outside the internal volume, the glass extending at the first end of the acquisition opening, - a first seal ensures the tight closure of the mounting opening by the image acquisition device and a second seal ensures the tight closure of the receiving opening by the light source.

[0014] According to another aspect, the invention relates to a device for inspecting at least one container extending along an axis, the inspection device comprising a support for receiving a container and an imaging device as described above, the axial direction of the imaging device being coincident with the axis of the container when the latter is received by the receiving support.

[0015] Other aspects and advantages of the invention will appear more clearly on reading the description which follows, given solely by way of non-limiting example, and made with reference to the appended drawings, in which:

[0016] [Fig-1] - [Fig.l] is a schematic perspective representation of a part of a device for inspecting a container comprising an imaging device according to the invention, [Fig.2] - [Fig.2] is a schematic perspective representation of the imaging device of [Fig.l], and [Fig.3] - [Fig.3] is a schematic cross-sectional representation of the imaging device of [Fig.2], showing the interior of the housing.

[0017] With reference to Figs. 1 and 2, a device 1 for imaging a container, more particularly a preform 2, is described, comprising an image acquisition device 4 and a light source 6 mounted on a housing 8.

[0018] The preform 2 is intended to form a container after steps of heating the preform 2 and blowing, or stretch-blow molding, the preform 2. Such a preform 2 essentially comprises a body 10 and a neck 12. The body 10 extends along an axis A and has, for example, the shape of a test tube extending between a bottom and the neck 12, which forms an open end of the test tube.

[0019] The neck 12 extends for example between a collar 14, extending from a radial plane substantially perpendicular to the axis A projecting outwards from the body 10, and a rim 15, forming the upper surface and the upper end of the preform 2. The collar 14 forms for example a surface for transporting the preform 2 and the finished container made from the preform 2. The rim 15 defines and surrounds the open end of the preform 2.

[0020] The part of the preform 2 extending from the collar 14 to the rim 15 comprises, for example, a thread 16 making it possible to fix a stopper on the container made from the preform 2.

[0021] The preform 2 is made of a thermoplastic material, for example polyethylene terephthalate (PET). The body 10 of the preform 2 becomes malleable when the body 10 of the preform is heated above the glass transition temperature of the thermoplastic material during a step of heating the preform 2 so that the body 10 can then be deformed to form the body of a container when compressed air is injected into the preform 2 through the open end during a step of blowing or stretch-blow molding the preform 2. In a known manner, the neck 12 of the preform 2 is not heated during the heating step and remains undeformed during the blowing or stretch-blow molding step so that the neck 12 of the preform 2 has the shape of the neck of the container made from the preform 2.

[0022] In order to produce a good quality container, it is necessary to ensure that the preform 2 is itself of good quality and complies with certain parameters, in particular at the neck 12 thereof, and more particularly at the collar 14 and / or the rim 15. The presence of scratches and / or a defect in the joint plane in the collar 14 and / or the rim 15 must be avoided. Furthermore, for certain preforms 2, it is necessary to identify the position of a mark on the collar 14 making it possible to detect the angular orientation of the preform 2. Such an angular orientation may in fact be important for the subsequent processing of the preform 2 and / or the container obtained from the preform 2, as known per se. Finally, the collar 14 and / or the rim must have given dimensions with a certain tolerance margin.It is understood that this list of parameters is given only as an example and that other parameters may be taken into account to ensure that the finished container produced from the preform will be of good quality.

[0023] To verify that the collar 14 and / or the rim 15 comply with these parameters, it is provided to inspect the collar 14 and / or the rim 15, for example before and / or after heating the preform 2, by means of an inspection device comprising the imaging device 1 which is arranged to acquire at least one image of the collar 14 and / or the rim 15 of the preform 2 to be inspected.

[0024] More particularly, the imaging device 1 is arranged to acquire at least an image of the collar 14 and / or the rim 15 in the radial plane in which this collar 14 and / or this rim 15 extends. In other words, the imaging device 1 is placed above or below the preform 2 and is arranged to acquire images in a shooting direction substantially parallel to the axis A of the preform 2 in a field of view perpendicular to the axis A corresponding to the radial plane in which the collar 14 and / or the rim 15 extends. According to one embodiment, the shooting direction is aligned, that is to say merged, with the axis A of the preform 2, as more particularly visible in Fig. 3. In order to obtain images of good quality and usable for inspection purposes, the imaging device 1 is further arranged to illuminate the collar 14 and / or the rim 15 depending on the shooting direction.In other words, the direction of emission of the light illuminating the collar 14 and / or the rim 15 is the same as the shooting direction.

[0025] For this purpose, as shown in [Fig. 3], the housing 8 defines an internal volume 18 receiving a semi-reflecting plate 20 towards which the image acquisition device 4 and the light source 6 are oriented. The semi-reflecting plate 20 is then arranged to align the shooting direction of the image acquisition device 4 and the direction of the light emitted by the light source 6 on an axial direction passing through an acquisition opening 22 of the housing 8 and substantially parallel, or even merged, with the axis A of the preform 2. More particularly, the semi-reflecting plate 20 is for example a 50 / 50 plate, that is to say transmitting 50% of the light and reflecting 50% of the light.

[0026] For this purpose, the image acquisition device 4 is mounted on a mounting opening 24 of the housing 8 arranged so that the image acquisition device 4 is oriented towards the semi-reflecting plate 20. According to the embodiment shown in [Fig. 3], the image acquisition device 4 is more particularly arranged opposite the transmitting face 26 of the semi-reflecting plate 20 so that the acquired images are transmitted in the axial direction towards the image acquisition device 4. Thus, according to this embodiment, the shooting direction of the image acquisition device 4 is directly coincident with the axial direction and the acquired images are transmitted directly to the image acquisition device 4 through the semi-reflecting plate 20 without being deflected by the latter.In this case, the mounting opening 24 is parallel to the acquisition opening 22, these openings being coaxial and extending in the axial direction. The mounting opening 24 extends between the inner volume 18 of the housing 8 and the outside of the housing 8 and the image acquisition device 4 is mounted on this mounting opening 24 from the outside of the housing 8. In other words, during the mounting of the image acquisition device 4, the latter is approached from the outside of the housing 8 and is fixed on the mounting opening 24 by passing through it from the outside towards the volume. internal 18 of the housing 8. Thus, the image acquisition device 4 remains accessible from outside the housing 8 and can easily be removed from it, for example to replace it with another image acquisition device 4 or for maintenance operations.

[0027] According to an embodiment shown in the figures, the image acquisition device 4 comprises a lens 28 mounted on an acquisition unit 30 to form a camera capable of acquiring images. When the image acquisition device 4 is mounted on the mounting opening 24, the lens 28 extends for example into the internal volume 18 and the acquisition unit 30 extends outside the housing 8, as shown in [Fig. 3]. Thus, when mounting the image acquisition device 4, the lens 28 is passed through the mounting opening 24 and the acquisition unit 30 is applied against the mounting opening 24 so as to close it.

[0028] The image acquisition device 4 is mounted in a sealed manner on the mounting opening 24. In other words, when the image acquisition device 4 is mounted on the mounting opening 24, any element coming from the outside, in particular dust or a liquid, is prevented from entering the internal volume 18 of the housing 8 by passing through the mounting opening 24. According to one embodiment, this sealing is ensured by a first seal 32 ensuring the sealed closure of the mounting opening 24 by the image acquisition device 4.

[0029] The light source 6 is received in a receiving opening 34 of the housing 8 arranged so that the light source 6 is oriented towards the semi-reflecting plate 20. According to the embodiment shown in [Fig. 3], in which the image acquisition device 4 is arranged opposite the transmitting face 26 of the semi-reflecting plate 20, the light source 6 is arranged opposite the reflecting face 36 of the semi-reflecting plate 20 so that the light emitted by the light source is reflected on the semi-reflecting plate 20 to be oriented in the axial direction towards the acquisition opening 22 after reflection on the semi-reflecting plate.Thus, according to this embodiment, the direction of emission of the light from the light source 6 is substantially perpendicular to the axial direction for a semi-reflecting plate 20 oriented at 45° relative to the axial direction and the light emitted by the light source 6 is reflected on the reflecting face 36 of the semi-reflecting plate to be merged with the shooting direction and the axial direction after reflection. In this case, the receiving opening 34 is perpendicular to the acquisition opening 22 and to the mounting opening 24. The receiving opening 34 extends between the interior volume 18 of the housing 8 and the exterior of the housing 8 and the light source 6 is mounted on this receiving opening 34 from the exterior of the housing 8. In other words, during the mounting of the light source 6, the latter is approached from the exterior of the housing 8 and is fixed in . the receiving opening 34 passing through it from the outside to the internal volume 18 of the housing 8. Thus, the light source 6 remains accessible from the outside of the housing 8 and can easily be removed from it, for example to replace it with another light source or for maintenance operations.

[0030] The light source 6 is for example arranged to emit radiation in the visible range, and more particularly between 400 and 700 nanometers.

[0031] The light source 6 is mounted in a sealed manner on the mounting opening 24. In other words, when the light source 6 is received in the receiving opening 34, any element coming from the outside, in particular dust or a liquid, is prevented from entering the internal volume 18 of the housing 8 by passing through the receiving opening 34. According to one embodiment, this sealing is ensured by a second seal 38 ensuring the sealed closure of the receiving opening 34 by the light source 6.

[0032] It is understood that the mounting 24 and receiving 34 openings may be arranged relative to the semi-reflecting plate 20 so that the semi-reflecting plate transmits the light emitted by the light source 6 in the axial direction and to reflect the images towards the image acquisition device 4. Thus, in this case, the mounting opening 24 is arranged so that the image acquisition device 4 is oriented towards the reflecting face 36 of the semi-reflecting plate 20 and the receiving opening 34 is arranged so that the light source 6 is oriented towards the transmitting face 26 of the semi-reflecting plate 20. Also in this case, the mounting opening 24 is perpendicular to the acquisition opening 22 and the receiving opening 34 is parallel and coaxial with the acquisition opening 22.

[0033] The acquisition opening 22 is sealed by a transparent window 40 extending into the acquisition opening 22. Thus, the window 40 prevents the passage of any element, in particular dust or a liquid, towards the internal volume 18 via the acquisition opening 22. According to one embodiment, the acquisition opening extends in the axial direction between a first end 42 opening into the internal volume 18 and a second end 44 opening outside the internal volume 18 and the window 40 is mounted in the acquisition opening 22 so as to extend at the first end 42. Such an embodiment makes it possible to position the window 40 set back inside the acquisition opening 22 so that it is not directly exposed to the external environment of the housing 8, which limits the risks of damaging the window. 40, for example by crossing this one out.The window 40 is for example made of glass or plastic material. The window 40 is for example anti-reflective and transmits 100% of the light without modifying its path. Thus, the light leaving the housing 8 and entering it through the acquisition opening is completely oriented according to the . axial direction. A seal is for example provided around the window 40, between the latter and the housing 8 in order to ensure sealing at the acquisition opening 22 receiving the window 40.

[0034] As described above, all the openings of the housing 8 are sealed so that the internal volume 18 is inaccessible from the outside of the housing 8 when the image acquisition device 4 is mounted on the mounting opening 24 and the light source 6 is mounted on the receiving opening 34. This makes it possible to protect the semi-reflecting plate 20, the objective 28 of the image acquisition device 4 and the light source 6 from the external environment of the housing 8 and to preserve the quality of the images acquired by the image acquisition device 4. The sealing of the housing 8 is for example in accordance with the sealing criterion IP66 (protection index 66) defined by the standard NF EN 60 529.

[0035] The housing 8 is advantageously made to limit, or even eliminate, the reflections of light inside the internal volume 18, apart from the reflections on the reflective face 36 of the semi-reflecting plate 20. For this purpose, the housing 8 is for example made of a non-reflective material and / or the internal wall of the housing 8 delimiting the internal volume 18 of the housing 8 is coated with a non-reflective material, for example a felt and / or a black coating. In addition, in order to further avoid reflections, the shape of the internal wall is for example arranged to limit the projecting angles inside the internal volume 18. For this purpose, as visible in the figures, the internal wall comprises curved and / or textured sections at least around the mounting 24, reception 34 and acquisition 22 openings.By curved sections, it is meant for example that the internal wall has a circular, ovoidal or elliptical section around the mounting 24, reception 34 and acquisition 22 openings. When edges must extend into the internal volume 18 of the housing 8, these are for example rounded to avoid forming reflection zones in the internal volume 18, as more particularly visible in [Fig. 3]. By textured sections, it is meant that the internal wall of these sections comprises shapes, such as a serration, arranged to multiply the reflections of light between these shapes and thus form a light trap preventing the trapped light from being reflected inside the internal volume 18.

[0036] According to one embodiment, the housing 8 further comprises at least one maintenance opening extending opposite the semi-reflecting blade 20 and closed in a sealed and reversible manner by a cover 46 during normal operation of the imaging device 1. Such a maintenance opening allows access to the internal volume 18 when the cover 46 is removed from the maintenance opening, for example to allow the semi-reflecting blade 20 to be changed or to provide access thereto for maintenance purposes. The cover 46 is for example made in the same material as the housing 8 and is also rounded in order to limit the reflection of light. A seal is for example provided between the cover 46 and the maintenance opening to maintain the sealing of the housing 8 at the maintenance opening.

[0037] The imaging device described above is particularly compact, which makes it easy to install in a container production facility 2.

[0038] According to the embodiment shown in [Fig.l], the imaging device 1 is for example mounted on a bracket 48 to extend opposite a preform support 2. Such a support can be movable relative to the imaging device, the imaging device then being adapted to acquire images of a succession of preforms passing opposite the imaging device 1. The imaging device 1 is for example articulated on the bracket 48 in order to allow the imaging device 1 to be repositioned relative to the preform 2 opposite, in particular to align the axis A of the preform 2 with the axial direction of the imaging device 1 if the preform 2 is inclined on its support.

[0039] It should be noted that the above description has been made with reference to the inspection of a collar 14 and / or a rim 15 of a preform 2 because, in this context, it is important that the light emitted by the light source 6 is aligned with the shooting direction of the image acquisition device 4. However, it is understood that the invention can be applied to the inspection of the body 10 of a preform 2 and / or its neck 12, or even to the inspection of a finished container obtained from a preform 2.

[0040] Thus, the invention also generally relates to a device for inspecting a container extending along an axis A, the inspection device comprising a support for receiving a container and an imaging device 1 as described above, the axial direction of the imaging device 1 being coincident with the axis A of the container when the latter is received by the receiving support.

Claims

Claims

1. Imaging device (1) for a container inspection device comprising an image acquisition device (4) oriented towards a semi-reflecting plate (20) and a light source (6) oriented towards said semi-reflecting plate (20), said semi-reflecting plate (20) being arranged to align the direction of shooting of the images of the image acquisition device (4) and the direction of the light emitted by the light source (6) in an axial direction, said semi-reflecting plate (20) extending in an internal volume (18) of a housing (8) comprising an acquisition opening (22) extending in the axial direction, characterized in that the housing (8) comprises a mounting opening (24) for the image acquisition device (4), said image acquisition device (4) being tightly mounted on said mounting opening (24) from outside the internal volume (18),and a receiving opening (34) for the light source (6), the light source (6) being received in a sealed manner by said receiving opening (34) from outside the internal volume (18), the internal volume (18) of the housing (8) being closed in a sealed manner by a window (40) extending into the acquisition opening (22), by the image acquisition device (4) and by the light source (6).,

2. An imaging device according to claim 1, wherein the semi-reflecting plate (20) is arranged to transmit the images to the image acquisition device (4) in the axial direction and to reflect the light emitted by the light source (6) in the axial direction.

3. An imaging device according to claim 1, wherein the semi-reflecting plate (20) is arranged to transmit the light emitted by the light source (6) in the axial direction and to reflect the images towards the image acquisition device (4).

4. An imaging device according to any one of claims 1 to 3, wherein the image acquisition device (4) comprises a lens (28) extending into the internal volume (18) of the housing (8) and said lens (28) being mounted on an acquisition unit (30) extending outside the internal volume (18).

5. An imaging device according to any one of claims 1 to 4, wherein the housing (8) comprises a maintenance opening extending opposite the semi-reflecting plate (20), said maintenance opening being closed in a sealed and reversible manner by a cover (46).

6. An imaging device according to any one of claims 1 to 5, wherein the housing (8) comprises an internal wall delimiting the internal volume (18), said internal wall being made of or coated with a non-reflective material.

7. An imaging device according to claim 6, wherein the inner wall comprises curved and / or textured sections at least around the acquisition opening (22), the mounting opening (24) and the receiving opening (34).

8. Imaging device according to any one of claims 1 to 7, in which the acquisition opening (22) extends between a first end (42) opening into the internal volume (18) and a second end (44) opening outside the internal volume (18), the window (40) extending at the first end (42) of the acquisition opening (22).

9. An imaging device according to any one of claims 1 to 8, wherein a first seal (32) ensures the sealing of the mounting opening (24) by the image acquisition device (4) and a second seal (38) ensures the sealing of the receiving opening (34) by the light source (6).

10. Device for inspecting at least one container extending along an axis (A), the inspection device comprising a support for receiving a container and an imaging device (1) according to any one of claims 1 to 9, the axial direction of the imaging device (1) being coincident with the axis (A) of the container when the latter is received by the receiving support.

Images