EP1604192A1

EP1604192A1 - Full inspection of the inner wall of transparent containers

Info

Publication number: EP1604192A1
Application number: EP03722259A
Authority: EP
Inventors: Edgar Wagener; Franz Häring; Kurt Spiegelmacher
Original assignee: Syscona Kontrollsysteme GmbH
Current assignee: Syscona Kontrollsysteme GmbH
Priority date: 2003-03-10
Filing date: 2003-04-04
Publication date: 2005-12-14
Also published as: DE10394241D2; DE10310273A1; WO2004081550A1; AU2003229511A1

Abstract

The invention relates to a method and device for automatic and substantially thorough detection of impurities or foreign bodies in the inner side wall area of transparent containers, such as bottles having a narrow neck, which are continuously conveyed past inspection devices by means of a laterally engaging transport device in a linear manner or which are conveyed by means of rotating receiving star-shaped elements provided with recesses for said containers. The container is photographed by a camera located below the bottom of the container and the images are respectively processed by an electronic image processing system and are analysed. A lighting device, which is used to light up the inner wall, is arranged on the side of the container facing the camera. The individual recording units, consisting of a camera and an opposite-lying lighting device, can be accommodated in separate stations or in a common station with coaxially opposite-lying cameras and lighting units.

Description

Full inspection of the inner wall of transparent containers

Description of the invention:

The present invention relates to a method and device for the automatic and largely complete detection of contaminants or foreign bodies in the inner side wall area of empty transparent containers, such as e.g. Bottles with narrow sharks, which are guided linearly past inspection devices by means of a laterally acting transport device or by a rotating receiving star with recesses for the containers.

Before filling transparent containers e.g. with drinks, they must be checked for cleanliness, especially inside. Contamination on the inside, a wide variety of particles or interferences in the container material are to be recognized in known solutions either with a camera arranged on the side, the transparent side walls of the container, or through the container opening looking directly into the interior of the container, in particular the bottom of the container. When recording the side wall of the container, preferably transmitted light or dark field lighting is used (EP 89 109 453.4; EP 1 1143 237 A1), lenses or collecting mirrors serve to improve the beam path (P 690 08 676.8). In order to be able to hold the container as completely as possible without having to move the containers apart from one another, complex mirror cabinets or a container rotation of the container in question are required.

In the case of another solution (DE 43 00 169 A1), laser-assisted spectral analysis supposedly detects in particular small impurities. Other solutions focus on the direct absorption of the inner wall near the floor and the container floor by e.g. neck-like container opening using light sources under the floor (Canadian patent 2,300,312; GP 2 212911). There are also solutions for inspecting the container bottom, in which the recording camera is arranged under the container and is directed onto the transparent container bottom using a ring illumination (J 07092107 A). It is also known to use segmented mirror optics to record and analyze the interior of vessels at least near the opening or mouth area using a camera (DE 195 42 630 C2).

The solutions with lateral detection of the transparent containers have the disadvantage that the interior cannot be detected directly, but only through the container wall. Impurities and the like. depicted on all outer and inner container wall surfaces penetrated by transmitted light. Together with faults caused by the packaging material itself, this leads to incorrect recognition and localization. Another disadvantage is that the containers, for example in linear inspectors, have to be rotated by a certain angle of rotation so that the side wall can be inspected all around. This requires corresponding complex mechanisms with all the associated disadvantages. If the transparent container has external structures or imperfections, or if it is printed with hot stamping or the like, all the contaminants behind it cannot be seen.

If the inside of a bottle-shaped container is opened through its opening, e.g. taken up through the mouth of the container neck, shape-related shadow areas remain completely unchecked. However, this is the case with a large number of containers, in particular with a pronounced neck area.

The object of the present invention is to eliminate the disadvantages mentioned and - for the purpose of the best possible interior hygiene, in particular of reusable containers - to implement a more complete interior inspection with increased detection reliability. This object is achieved by the method and the device according to claim 1. Preferred developments and solution details are described in claims 2 to 8.

Through the solution presented, in which the inside of the container is captured both by a camera above the container mouth, which captures the inner wall areas visible in this way by means of a radiation column, and by a camera below the container base, which is visible from this side through the transparent container base Inner wall areas recorded, recorded, practically all inner wall areas, even in pronounced shoulder areas of a container, can be recognized and contaminants, various particles or defects in the container material can be reliably identified on the inner wall side. The two cameras provided with the respective opposite light source can be arranged in two stations arranged in a space-saving manner along the transport route through the inspection device or in a common station in which the cameras together with the optical elements and the lighting units concentrically surrounding them are aligned his. With the help of the optics and image data evaluation according to the invention, it is even possible to look through a non-uniformly shaped, transparent floor with little interference. Since the inner wall of the container can be accommodated in this way, rotation relative to the transport device is no longer necessary. In cases where misinterpreted structural elements or surfaces of the container to be inspected, For example, relief-like structures in the transparent material or imprints on the outside, which can be seen on the image of the inner wall, software-based fading out according to the invention, separate evaluation of optically delimitable areas or filters during the inspection of the containers can avoid inspection error judgments.

Fig. 1 shows the basic arrangement of the essential components of the device according to the invention, including exemplary beam paths (17; 18).

List of reference symbols in Fig. 1:

1 container

2 floor

3 mouth

4 shoulder area

5 interior wall area

6 conveyor belts

7 lighting unit below

8 lighting unit above

9 lens below

10 lens above

11 camera below

12 camera above

13 radiation collector

14 lens unit

15 protective screen

16 Beam path to the camera above

17 Beam path to the camera below In an exemplary embodiment of the device according to the invention according to FIG. 1, a container, for example a glass bottle (1), is captured by a camera (12) above the container mouth (3), which detects the inner wall regions (5) that are visible in this way by means of a radiation collector (13) , and - in a separate station from this - by another camera (11) under the container base (2), which captures the inner wall areas visible from this side, eg the shoulder area (4), using a lens unit (14). According to the invention, the images are processed and analyzed in a detection-supporting manner by means of an electronic image processing system. On the side of the container (1) opposite the camera (11, 12) there is a permanently or pulsed lighting unit (7, 8) illuminating the inner wall in the transmitted light principle. If the containers are picked up, these lighting units (7, 8) can be concentrically broken through in a single station so that the cameras can be aligned with the central beam axis. The light is preferably emitted diffusely, for example by using an upstream diffuser (9, 10) or the like, and is preferably located at a distance of 10 to 100 mm above the mouth (3) or. under the bottom (2) of the container (1). These diffusing screens can either simultaneously fulfill a protective function for the lighting units (7, 8) or can also be protected by an additional, upstream, transparent protective element.

The largely vertical containers (1) are moved horizontally at the level of the mouth or bottom-side receiving station by a known transport device which engages the side wall of the container, for example transport belts (6) pressed on both sides. This allows a clear view of the container (1) for a short time. A rotational movement of the packs superimposed on the advance movement is advantageously not required. The containers (1) can pass the inspection stations described in very close succession. In one embodiment of the device according to the invention, the lighting units (7, 8), respectively. optical devices, such as radiation collector (13) and lens (14) in front of the respective camera (11, 12), respectively at a distance of 10 to 100 mm above the mouth (3) and. arranged under the bottom (2) of the passing container (1). The above-mentioned device components are designed to be adjustable in height either manually or by a motor. The camera (11) below, including the lens (14), is provided with a shoulder-free and easily insertable transparent protective screen (15), which is flush with the housing for the camera (11), lens unit (14) and possibly the adjacent lighting unit (7), protected from dirt, broken glass or moisture, according to a proposal according to the invention in particular this bottom-side protective pane (15) by pulsed or permanently blowing compressed air or an intermittent or permanent mechanical wiper device is freed from water drops, dirt particles or the like.

In a further development of the device for the method according to the invention, the lighting of the container can take place in a space-saving manner by means of the mouth and bottom lighting unit simultaneously and in a common station. The cameras, including the optical elements, are surrounded concentrically by ring-shaped lighting units and are flush with one another. In this case, the container is either picked up simultaneously from both sides or one after the other at the smallest possible time interval.

It can be seen from the beam paths (17, 18) exemplarily shown in Fig. 1 into the interior of a bottle-like container (1) that practically the entire interior wall area can be imaged. This also applies in particular to the shoulder area (4) of such containers, which is characterized by a container opening side, i.e. in the example on the mouth side, camera (12) cannot or cannot be completely detected despite a radiation collection by a suitable radiation collector (13). The bottom-side lens unit (14) is arranged at such a distance from the bottom (2) of the container (1) and is designed and adjusted so that the focus of the image recorded by the camera (11) lies in the inner wall area above the bottom (2) and that the see-through floor (2) lies in the complete unsharpness area. In this way, optical interference from container floors, e.g. Curvatures, material structures and the like, in connection with a suitably adjusted light source, i.e. Illumination unit (8) and lens (10) on the opposite side of the container (1) can already be largely optically eliminated.

Containers that contain residual liquids to a certain extent, e.g. from the washing process, or contain other residues, are inspected by an appropriate and known device, e.g. an infrared resp. High-frequency inspection station, recognized and discharged from the transport line either before or after the interior wall inspection according to the invention. This measure is necessary in order to avoid incorrect inspection results due to larger layers of liquid in the container that impair the beam path.

Digital CCD cameras are preferably used. Object shapes, image structures, differences in brightness or color are analyzed according to the invention by a downstream electronic image processing system with appropriate software. In the course of subsequent image data processing, characteristic image elements are isolated and assessed, for example, by comparing parameters or image patterns in terms of the detection objective of the method according to the invention. In this way it is also possible to correctly interpret such picture elements that look similar to contamination or a foreign body. In a further development according to the invention, misinterpreted structural elements or areas of the container to be inspected, for example structures in transparent material or prints on the outside, are assessed correctly by software-based blanking, separate evaluation of optically delimitable areas or filters, ie not as soiling or the like.

Misinterpretations are also due to possible, non-eliminable defects in the recorded blank image without containers, e.g. through drops, shards, other foreign bodies or larger scratches on diffusing screens (9, 10) in front of the lighting units (7, 8). In a further development of the method and a corresponding device according to the invention, in the course of programmed self-control routines, such defects are detected, limited and specifically excluded from the container assessment by means of image data processing.

Claims

Expectations:

1.Method and device for the automatic and largely complete detection of contaminants or foreign bodies in the inner side wall area of empty transparent containers, such as Bottles with a narrow neck, which are guided linearly past inspection devices by means of a laterally acting transport device or by a rotating receiving star with recesses for the containers, characterized in that the container is both from a camera above the mouth of the container, which detects the visible inner wall areas by means of a radiation collector , as well as from a camera under the container base, which detects the inner wall areas visible from this side by means of a lens unit, and the images are processed and analyzed using an electronic image processing system, whereby the inner wall is on the side of the container opposite the camera illuminating, continuously or pulsed lighting unit is attached, and the two cameras with the respective opposite light source in any two along the transport route the inspection device arranged stations or also in a common station, in which the cameras including optical elements and the lighting units concentrically surrounding them are located opposite one another in alignment.

2. The method and device according to claim 1, characterized in that the bottom-side lens unit is arranged at such a distance from the bottom of the container and the focus range of the image taken by the camera can be adjusted by it so that the see-through bottom lies in the completely unsharp area ,

3. The method and device according to claim 1 or 2, characterized in that containers, which to a certain extent also contain residual liquid or other residues, are recognized for this purpose by an upstream inspection station and treated separately.

4. The method and device according to claim 1, 2 or 3, characterized in that the lighting of the container can be carried out simultaneously by the mouth and the bottom-side lighting unit if necessary.

5. The method and device according to claim 1 to 4, characterized in that misinterpreted structural elements or surfaces of the container to be inspected, For example, structures in the transparent material or prints on the outside, through software-based blanking, separate evaluation of optically delimitable areas or filters during the container inspection, do not influence the inspection result.

6. The method and device according to any one of claims 1 to 5, characterized in that the lens units of the cameras are each protected by a quickly removable, transparent protective pane which is flush with the receiving housing for the camera, lens unit and possibly adjacent lighting unit, in particular the bottom-side protective pane is freed from water droplets, dirt particles or the like by pulsed or permanently blowing compressed air or an intermittent or permanent mechanical wiping device.

7. The method and device according to any one of claims 1 to 6, characterized in that by means of programmed self-control routines, any non-eliminable defects in the recorded blank image are recorded without a container, limited and excluded from the container assessment.

8. The method and device according to one of claims 1 to 7, characterized in that the lighting units respectively at a distance of 10 to 100 mm above the mouth. is arranged under the bottom of the container and generates diffuse light.