Inspection of objects

Abstract

The invention relates to an apparatus for inspecting objects (10), comprising a transport device (20), which transports the objects (10) along a specified transport path (22), and comprising an inspection device (24), which inspects the objects (10) during transport, wherein the inspection device (24) is designed to create an X-ray recording (34) and an optical recording (44) of an object (10) to be inspected, wherein the X-ray recording (34) and the optical recording (44) are created at the same time and at the same recording angle, and wherein the two recordings (34, 44) are evaluated by an evaluation device (50). The invention also relates to a corresponding inspection method.

Description

[0001] Inspection of objects

[0002] The present application relates to a device and a method for inspecting objects.

[0003] In the beverage, food, and pharmaceutical industries, objects such as containers and bottles are transported at a throughput of up to 90,000 bottles per hour. Therefore, the time available for inspecting the containers and evaluating the recorded data is very limited.

[0004] The state of the art provides a wide variety of methods for inspecting objects inline, i.e., during transport on a conveyor system. Known inspection methods include chemical, physical, and mechanical measurement methods, as well as optical measurement methods. Depending on the inspection task, several inspection methods are often used to ensure the integrity of the objects to be inspected. Typically, the data sets obtained using the different measurement methods are evaluated independently of one another. Objects identified as defective are removed from the product stream and, if necessary, recycled.

[0005] Which measurement methods are used for inspection usually depends on the specific inspection task. X-ray technology has proven effective for detecting high-density foreign objects such as stones and metal fragments at the bottom of filled beverage bottles. X-ray technology is also advantageous when the objects themselves are made of different materials, such as metals and plastics. However, X-ray images often make it difficult to determine the contours of weakly X-ray-absorbing components. The poorer the contour detection, the less reliable the results of the data analysis.

[0006] DE 10 2007 040 488 A1 discloses an X-ray device for examining syringe caps with a cannula. A syringe cap, mounted on a holder, is inserted into the beam path between an X-ray source and an X-ray detector in such a way that a longitudinal axis of the syringe cap runs parallel to the main axis of the beam path. The advantage of this evaluation is that bent cannulas can be detected with a single X-ray setup. In particular, bent cannulas can be detected regardless of the direction in which the cannulas are bent. The method known from the prior art has several disadvantages. The evaluation is relatively crude, so no precise statements can be made about the degree of bending of the objects being examined. Furthermore, the method is not capable of inline processing.Therefore, this method can only be used to carry out random checks of syringe caps equipped with needles.

[0007] The object of the present invention is therefore to provide a device and a method that improves the evaluation of the objects to be inspected. In particular, the object of the present invention is to provide a device and a method that improves the evaluation of the objects to be inspected, regardless of the material of the objects to be inspected.

[0008] In particular, it is an object of the present invention to provide a device and a method with which the correct positioning of protective covers in pre-filled syringes or cannulas can be checked inline, i.e. in the production process.

[0009] At least one of these objects is achieved by the device according to the invention as defined in claim 1. The device for inspecting objects comprises a transport device that transports the containers along a predetermined transport path. The device further comprises an inspection device that inspects the objects during transport, wherein the inspection device is designed to create an X-ray image and an optical image of the object to be inspected. The X-ray image and the optical image are created simultaneously and at the same angle. Finally, the device comprises an evaluation device by means of which the two images are evaluated.

[0010] Because the X-ray image and the optical image are taken simultaneously and at the same viewing angle, these two images show exactly the same object. The two images can be quickly and precisely overlaid without any additional calculations. This allows the different contours visible in the individual images to be visualized and efficiently evaluated in a single image. Additional calculations to correct for a different acquisition time or angle are unnecessary.

[0011] According to the invention, the inspection device comprises at least one X-ray unit and one optical inspection unit. The X-ray unit comprises at least one X-ray source and at least one X-ray detector. The optical inspection unit comprises at least one light source and at least one camera. Preferably, both radiation sources are arranged on a first side of the predetermined transport path of the transport device.

[0012] The respective detectors, i.e., at least one X-ray detector and one camera, are advantageously arranged on a second side of the predefined transport path of the transport device. In this way, the objects are examined in transmitted light, which is usually the most suitable method for contour detection. However, there are essentially no limits to the possibilities for the skilled person. If it seems advantageous, the camera, for example, can also be arranged on the same side as the light source, so that the objects are examined in reflected light.

[0013] The transport path along which the objects to be inspected are transported is advantageously designed so that it crosses the beam path of the X-ray radiation and the optical radiation.

[0014] The objects to be inspected advantageously have a longitudinal axis. The objects to be inspected are advantageously aligned so that their longitudinal axis runs perpendicular to a transport plane defined by the transport device.

[0015] The objects are inspected in a direction that is not parallel to the objects' longitudinal axis. Advantageously, the objects are inspected transversely to the objects' longitudinal axis. Advantageously, the objects are inspected in a direction or plane that is parallel to the transport plane, or at least at a sufficiently small angle to the transport plane. Advantageously, the objects are inspected transversely to their longitudinal axis and in a direction or plane that is parallel to the transport plane.

[0016] The objects to be inspected are conveyed through the inspection device on the transport device. The inventive design of the inspection device prevents the transport device from crossing the beam path of the inspection device, which could potentially influence or block the X-ray and / or optical radiation.

[0017] The X-ray source can be designed to emit X-rays with a wavelength in the range of 1 pm to 10 nm or an energy in the range of 0.1 to 1000 keV. Typically, X-rays are used in the energy range of 10 to 100 keV. X-rays can be used in the energy range of 50 to 90 keV. X-rays can be used in the energy range of approximately 80 keV.

[0018] The light source can be any light source that emits visible light in the range of 380 to 760 nm. The light source can emit white light or monochromatic light. The light source can advantageously be based on LED technology. The selection of the light source and the radiation it emits can be adapted to the specific inspection task. The light source can also be designed to emit light in the UV-A, UV-B, or UV-C range, as well as in the IR range.

[0019] The inspection device can comprise an optical mirror. In this application, an optical mirror is understood to mean a mirror that reflects at least the light emitted by the light source. Preferably, the optical mirror is also substantially transparent to X-rays. Due to its permeability to X-rays, such an optical mirror can be inserted into the optical path between the X-ray source and the X-ray detector without interfering with the X-ray image. At the same time, however, such a mirror can deflect the light from the light source. Advantageously, the mirror is aligned such that it deflects the light from the light source toward the optical camera.

[0020] Preferably, the optical mirror is arranged on the second side of the predetermined transport path of the transport device. Both the X-ray radiation and the light are emitted from the respective radiation sources on the first side of the transport device in the direction of the object to be examined. After the X-ray radiation and the light have passed the object, the light is reflected by the optical mirror in the direction of the optical camera. The X-ray radiation, however, passes the optical mirror unhindered and strikes the X-ray detector in a straight line. This makes it possible to simultaneously record an X-ray image and an optical image of an object from an identical viewing angle.

[0021] The optical mirror can be made of a suitable material known to those skilled in the art. For example, a thin mirror made of conventional glass can be used. It is also conceivable to use plastic mirrors.

[0022] The X-ray source and / or the light source are preferably operated in flash mode. In flash mode, the radiation sources are only activated for a brief moment when the objects are directly in the beam path of the inspection system. Flash mode offers numerous advantages over continuous operation. Firstly, it significantly reduces radiation exposure. Secondly, motion blur is avoided and detection accuracy is increased.

[0023] Both radiation sources and their detectors are synchronized with each other via a higher-level control unit, so that the radiation sources are activated at the same time and the images are taken at exactly the same time.

[0024] The device according to the invention further comprises an evaluation device. The evaluation device is configured to superimpose the images from the X-ray camera and the optical camera. By superimposing the two images, structures or features that would otherwise only be visible in one of the two images can be directly compared and evaluated. Particularly when objects are made of materials that absorb little X-rays, determining their contours in X-ray images is often difficult or even impossible. By combining such an X-ray image with an optical image of the same object, information about such contours can be provided. The advantageous combination of the X-ray image and the conventional image allows more and more detailed information to be obtained than if each image were evaluated individually and independently.

[0025] The evaluation device can be configured not only to combine the two images from the X-ray camera and the optical camera, but can also be configured to analyze the combined image. In particular, the evaluation device can be configured to distinguish between defect-free and defective objects. The factors to be considered for this analysis naturally depend on the type of object being inspected.

[0026] Instead of one radiation source and one associated detector, several similar radiation sources and / or detectors can also be used. For example, an inspection device can also comprise two X-ray sources and two X-ray detectors, as well as two light sources and two optical cameras. The radiation sources and their associated detectors can each be arranged at an angle to one another so that the object to be inspected can be captured from different viewing angles. Capturing an object from different angles allows a stereoscopic calculation of the respective images, thus enabling a three-dimensional representation of the object to be inspected. To facilitate contour detection, each X-ray unit consisting of an X-ray source and an X-ray camera can generally also be assigned a conventional optical unit consisting of a light source and an optical camera.

[0027] The objects to be inspected can be any object used in the food, beverage, or pharmaceutical industries. For example, the objects can be containers, bottles, cans, vials, or other containers used in the food, beverage, or pharmaceutical industries.

[0028] The objects can be, in particular, disposable syringes, pre-filled syringes, cannulas, or similar applicators. The cannulas of such objects are usually made of metal. The other components of such objects, however, are usually made of plastic. The cannulas must always be provided with protective caps. These protective caps are also usually made of plastic. The protective caps serve, on the one hand, to mechanically protect the cannulas. On the other hand, the protective caps must fit perfectly to ensure the sterility of the cannulas. Since the protective caps are often made of opaque material, no qualified statement about the cannula can be made during a final inspection of such objects using purely optical means.Although X-ray techniques can be used to image the cannula itself, it is often not possible to determine its position in relation to the protective cap or the other components of the syringe.

[0029] With the device according to the invention, even such objects can be inspected very reliably. In particular, syringes with bent needles, syringes with punctured protective covers, syringes with internally punctured protective coatings, especially with punctured SNS (soft needle sheet) or RNS (rigid needle sheet), syringes with faulty sealing elements, or syringes with crooked tamper-evident closures can be identified. In addition, foreign substances, contaminants, and defects inside or on the surface of the protective covers can also be identified.

[0030] The inspection device according to the invention further comprises a rejection device configured to separate defective objects from the product stream. Such rejection devices are generally known to those skilled in the art. The type of rejection device used may depend on the type of objects to be inspected and the type of transport device used. The present invention also relates to a method for inspecting objects. The method comprises the following steps:

[0031] - Transporting objects on a transport device along a specified transport path,

[0032] - Inspecting the objects using an inspection device during transport,

[0033] - Creating an X-ray image and an optical image of the object to be inspected, whereby the X-ray image and the optical image are created at the same time and at the same angle, and

[0034] - Evaluation of the two images using an evaluation device.

[0035] The method according to the invention is particularly suitable for inspecting objects consisting of elements made of different materials. At least one of these materials is essentially transparent to X-rays or only weakly absorbs X-rays. At least one other element of the object is made of a material that is not transparent to X-rays. Typically, this other element is made of a metallic material.

[0036] The evaluation device is advantageously configured to overlay the images from the X-ray camera and the optical camera. Since the images are taken simultaneously and at the same angle, superimposing the images can be done quickly and easily. In particular, the images do not need to be rectified or otherwise calibrated or reconciled prior to overlay. By overlaying the two images, the contours of the X-ray-transparent elements of the objects to be inspected can be identified.

[0037] The method according to the invention is suitable for the inspection of containers, bottles, cans, vials, or other containers in the food, beverage, or pharmaceutical industries. The method according to the invention is particularly suitable for the inspection of packaged pharmaceutical products made essentially of plastic and containing metallic cannulas.

[0038] The method according to the invention can detect various defects in the objects to be inspected. Detectable defects include: syringes with bent needles, syringes with punctured protective covers, syringes with internally punctured protective elements, syringes with faulty sealing elements, or syringes with crooked tamper-evident closures. In addition, foreign substances, contaminants, and defects inside or on the surface of the protective cover can also be detected.

[0039] The present invention is described in more detail below with reference to the accompanying drawings, in which:

[0040] Fig. 1 shows a conventional inspection device according to the prior art,

[0041] Fig. 2 various evaluable X-ray images,

[0042] Fig. 3 various non-evaluable X-ray images,

[0043] Fig. 4 schematic structure of an inspection device according to the invention, and

[0044] Fig. 5 Overlay of an X-ray image and an optical image.

[0045] Fig. 1 shows a typical design of a conventional inspection device 10 currently used to inspect objects 12. In the embodiment of Fig. 1, the objects 12 to be inspected are pre-filled syringes, each of which has cannulas 14 provided with a protective hood 16.

[0046] These objects 12 are transported on a transport device 20, in this case on a conveyor belt, on a predetermined transport path 22 past an inspection device 24. The inspection device 24 comprises an X-ray source 30, which is provided on the right-hand side of the transport device 24 in the transport direction of the objects 12. On the opposite, left-hand side of the transport device 24, an X-ray detector 32 is provided, which creates X-ray images of the objects 12. These X-ray images are transmitted to an evaluation device (not shown). The evaluation device checks whether the inspected objects 12 comply with the specifications. Defective pre-filled syringes can, for example, have bent cannulas 14 or punctured protective hoods 16. The correct fit of the protective hoods 16 can also be checked.

[0047] Fig. 2 shows various easily analyzable x-ray images 34 of pre-filled syringes with cannulas 14 and protective hoods 16. In the center of the images, the metallic cannula 14 is visible with strong contrast. The plastic components of the protective hood 16 and the pre-filled syringe, in contrast, are shown with significantly weaker contrast. If the contours of the cannula 14 and the protective hood 16 are clearly visible, these x-ray images 34 can be evaluated relatively well. In the x-ray image 34 of Fig. 2a, for example, the lateral distance a1 between the cannula 14 and the side of the protective hood 16 can be determined. Likewise, in this x-ray image 34, the distance a2 between the tip of the cannula 14 and the front end of the protective hood 16 can be determined.

[0048] In Fig. 2b, the immersion depth b1 of the cannula 14 in the protective hood 16 can be determined.

[0049] In Fig. 2c, the cannula 14 is bent. For flawless objects, the cannula 14 should extend at a right angle from the cannula base c3. As can be seen in the image in Fig. 2c, an angle a results between the actual cannula orientation c1 and the expected cannula orientation c2. This angle a can be determined based on the image in Fig. 2c.

[0050] In the image shown in Fig. 2d, the cannula 14 is bent. On the other hand, the protective hood 16 is also positioned at an angle. Based on the visible lateral contours d1 and d2 of the protective hood 16, a longitudinal axis d3 running through the center of the protective hood 16 can be determined. The angle ß between the longitudinal axis d3 and the vertical d4 corresponds to the tilt angle of the protective hood 16.

[0051] The X-ray images in Fig. 2 clearly illustrate how important it is for the inspection during the final control of pre-filled syringes to capture the contours of both the metallic cannula 14 and the contours of the non-metallic components surrounding the cannula 14, such as the protective cap 16.

[0052] In Fig. 3, however, x-ray images 34 are shown which cannot be reliably evaluated. The x-ray images 34 also show objects 12 which consist of metallic and non-metallic components. Fig. 3a shows an x-ray image 34 of a cannula 14 with a protective cap 16. The cannula 14 is visible in the x-ray image 34 with a clear, dark contrast. Parts of the pre-filled syringe to which the cannula 14 is attached are also still clearly visible. However, the protective cap 16 of the cannula 14 is only shown with very weak contrast. The contours of the protective cap 16 cannot be recognized reliably enough for automatic evaluation. Therefore, the various geometric dimensions, such as the distance between the cannula 14 and the protective cap 16 or the orientation of the protective cap, cannot be reliably determined.

[0053] Fig. 3b also shows an x-ray image 34 of a cannula 14 with a protective cap 16. In Fig. 3b, the grayscale contrast is inverted, so that the cannula 14 is clearly visible in the x-ray image 34 with a bright, distinct contrast. In this x-ray image 34, parts of the pre-filled syringe to which the cannula 14 is attached are also clearly visible. However, the protective cap 16 of the cannula 14 is again shown with only very weak contrast. Such an x-ray image 34 cannot be reliably evaluated either.

[0054] Fig. 3c shows an x-ray image 34 of another pharmaceutical product. It shows an applicator 36 with a metallic injector pin 38. More precisely, the applicator 36 is a nasal applicator. This applicator 36 also comprises plastic components, such as a protective cap 16, and also metal components, such as the injector pin 38. In this x-ray image 34, the metallic injector pin 38 and the metallic springs 39 provided on the sides are also clearly visible thanks to their dark contrast. The details of the other housing components, in particular their contours, are barely or not at all visible in the x-ray image 34. In any case, the contrast is too weak to allow reliable determinations about the correct fit of the protective cap 16 of the applicator by means of automatic image evaluation.

[0055] Fig. 4 depicts an inspection device 100 according to the present invention. This inspection device 100 simultaneously creates an X-ray image 34 and a conventional optical image 44 of an object 12. Both images are taken at the same viewing angle.

[0056] The device 100 for inspecting objects 12 comprises a transport device 20 on which the objects 12 are transported along a predetermined transport path 22. In the illustrated embodiment, the transport device 20 is a circulating conveyor belt on which the objects 12 are conveyed along a rectilinear transport path 22.

[0057] The objects 12 to be inspected are pre-filled syringes, which are essentially made of plastic and have a metallic cannula 14. The metallic cannula 14 is provided with a protective cover 16.

[0058] The objects 12 are conveyed past an inspection device 24 by means of the transport device 20. The inspection device 24 is designed to create both an X-ray image 34 and a conventional optical image 44 of the objects 12 to be inspected. For this purpose, the inspection device 24 comprises a light source 40. The light source 40 is a conventional LED light source that irradiates the objects 12 to be inspected with white light. In the configuration of Fig. 4, the light source 40 is arranged on the right side of the transport device 20. The light rays 43 transmitted by the objects 12 to be inspected fall upon an optical mirror 46. The optical mirror 46 is made of thin glass and provided with a reflective layer. The optical mirror 46 reflects the incident light rays 43. At the same time, however, the optical mirror 46 is essentially transparent to X-ray radiation 33.The optical mirror 46 directs the light rays 43 onto a camera 42, in this case a CCD camera, which creates an optical image 44 of the objects 12. In Fig. 4, the mirror 46 is arranged so that the light rays are deflected by 90°.

[0059] In addition to the light source 40, the inspection device 24 also includes an X-ray source 30. The X-ray source 30 is a conventional X-ray source 30 that irradiates the objects 12 to be inspected with X-ray radiation 33 having an energy of approximately 80 keV. In the configuration of Fig. 4, the X-ray source 30 is also arranged on the right side of the transport device 20. The X-rays 33 transmitted by the objects 12 to be inspected pass through the optical mirror 46 essentially unhindered, since the optical mirror 46 is made of a material that is transparent to X-ray radiation 33. The X-ray radiation 33 strikes an X-ray detector 32 arranged behind the optical seal 46, which creates an X-ray image 34 of the objects 12.

[0060] The two radiation sources 30, 40, the X-ray detector 32, and the camera 42 are controlled by a control unit (not shown). The control unit is configured so that the two images 34, 44 are taken simultaneously.

[0061] The two images 34, 44 are then transmitted to an evaluation device 50. In the evaluation device 50, the two images 34, 44 are superimposed, with the contours of both images 34, 44 being combined into one image 54. The thus combined image 54 is then evaluated. During this evaluation, for example, the distances and angles of the individual components of the objects 12 to be inspected, as discussed above with reference to Fig. 2, can be determined.

[0062] Fig. 5 shows images of a pre-filled syringe. The images were taken using the inspection device 100 according to the invention. The objects 12 to be inspected are again pre-filled syringes, each comprising a cannula 14 and a protective cap 16.

[0063] Fig. 5a shows the camera image 44. In this image 44, the contours of the protective cap 16 of the pre-filled syringe can be seen in particular. Fig. 5b shows the x-ray image 34. In this image 34, the cannula 14 can be seen in particular. Fig. 5c shows the superimposition of both images 34, 44. In the overlay image 54, both the contours of the protective cap 16 and the contours of the cannula 14 can be seen. This overlay image 54 can then be evaluated to determine whether the pre-filled syringe complies with the specifications.

Claims

Patent claims 1. Device for inspecting objects (10) with a transport device (20) which transports the objects (10) along a predetermined transport path (22) and with an inspection device (24) which inspects the objects (10) during transport, wherein the inspection device (24) is designed to create an X-ray image (34) and an optical image (44) of an object (10) to be inspected, wherein the X-ray image (34) and the optical image (44) are created at the same time and at the same angle, and wherein the two images (34, 44) are evaluated by an evaluation device (50).

2. Device according to claim 1, wherein the inspection device (24) has an X-ray source (30) for generating X-ray radiation (33) and a light source (40) for generating light (43), which are preferably arranged on a first side of the predetermined transport path (22) of the transport device (20).

3. Device according to claim 2, wherein the inspection device (24) comprises an X-ray detector (32) and an optical camera (42) arranged on a second side of the predetermined transport path (22) of the transport device (20).

4. Device according to one of the preceding claims, wherein the inspection of the objects (10) takes place transversely to the predetermined transport path (22).

5. Device according to one of the preceding claims, wherein the objects (10) to be inspected have a longitudinal axis and wherein the inspection is carried out transversely to a plane, wherein the plane is spanned by the longitudinal axis of the objects (10) and the predetermined transport path (22).

6. Device according to one of the preceding claims, wherein the objects (10) to be inspected are inspected standing on the transport device (20), so that the longitudinal axis of the objects (10) runs perpendicular to the predetermined transport path (22).

7. Device according to one of the preceding claims, wherein the inspection device (24) comprises an optical mirror (46) and wherein the optical mirror (46) reflects the light (43) and at the same time is transparent to the X-ray radiation (33).

8. Device according to one of the preceding claims, wherein the optical mirror (46) is arranged in the beam path of the X-ray radiation (33) and the light (43), and wherein the optical mirror (46) allows the X-ray radiation (33) to pass in the direction of the X-ray detector (32) while the light (43) is reflected in the direction of the optical camera (42).

9. Device according to one of the preceding claims, wherein the evaluation device (50) is configured to superimpose the images (34, 44) of the X-ray detector (32) and the optical camera (42) and wherein the evaluation device (50) is preferably further configured to distinguish between defect-free and defect-affected objects (12).

10. A method for inspecting objects (12), comprising the steps: - transporting objects (12) on a transport device (20) along a predetermined transport path (22), - inspecting the objects (12) by means of an inspection device (8) during transport, - creating an X-ray image (34) and an optical image (44) of the object (12) to be inspected, wherein the X-ray image (34) and the optical image (44) are created at the same time and at the same angle, and - evaluating the two images (34, 44) by means of an evaluation device (50).

11. Method according to claim 10, wherein the objects (12) to be inspected comprise elements made of different materials, wherein at least one of these materials is substantially transparent to X-ray radiation (33) and wherein at least one of these materials is substantially non-transparent to X-rays (33).

12. Method according to one of claims 10 or 11, wherein the evaluation device (50) is designed to superimpose the images (34, 44) of the X-ray detector (32) and the optical camera (42) so that the contours of the elements transparent to X-ray radiation (33) can be recognized by the superimposition of the two images (34, 44).

13. Method according to one of claims 10 to 12, wherein the objects (12) to be inspected are, for example, containers, syringes, cannulas or applicators from the food, beverage or pharmaceutical industries.

14. The method according to any one of claims 10 to 13, wherein the objects (12) to be inspected are packaged pharmaceutical products comprising metallic cannulas, the metallic cannulas (14) being provided with plastic protective hoods (16).

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