Apparatus for inspecting containers, in particular cans

Abstract

A device for inspecting containers which have an opening includes a transport device which transports the objects along a configured transport path. The device includes a monitoring device which is configured to monitor at least one region of an inner wall of the container through the opening. The monitoring device is configured to capture spatially resolved images, and has a lighting device configured to illuminate at least one region of the inner wall, is arranged between the monitoring device and the container.

Claims

1. An apparatus for inspecting objects which have an opening, comprising a transport conveyor configured to transport the objects along a predetermined transport path, an imaging monitor which is configured to monitor at least one region of an inner wall of the object through the opening of the object, wherein the imaging monitor is configured to capture spatially resolved images, wherein the apparatus has an illuminator configured to illuminate at least one region of the inner wall wherein the illuminator is arranged between the imaging monitor and the object, wherein an imager is focused in the monitoring direction such that the pupil region and/or focal point is located in the center of a transit region of the illuminator, wherein the object to be inspected is a can having a non-transparent base and side walls, and wherein a beam path extending from the object towards the monitoring. device pass through the transit region and the transit region is configured as a hole in the illumination device and has a diameter which is between 1 mm and 20 mm.

2. The apparatus according to claim 1, wherein the illuminator is configured to emit diffuse light.

3. The apparatus according to claim 2, wherein the imaging monitor has an objective with a pupil arranged in front.

4. The apparatus according to claim 3, wherein the illuminator is designed as a planar body or has a planar body that is arranged perpendicular to an optical axis of the imaging monitor and has, viewed along the optical axis, a thickness which is greater than 0.2 mm, and less than 40 mm.

5. The apparatus according to claim 4, wherein a surface of the illuminator is greater than a cross-section of the object to be inspected.

6. The apparatus according to claim 2, wherein the illuminator has a transit region through which a beam path extending from the object towards the imaging monitor can pass.

7. The apparatus according to claim 6, wherein the transit region is configured as a hole in the illuminator and has a diameter which is between 1 mm and 20 mm.

8. The apparatus according to claim 2, wherein a shutter device is arranged between the illuminator and the imaging monitor.

9. The apparatus according to claim 1, wherein the imaging monitor has an objective with a pupil arranged in front.

10. The apparatus according to claim 1, wherein the illuminator is designed as a planar body or has a planar body, that arranged perpendicular to an optical axis of the imaging monitor and has, viewed along the optical axis, a thickness which is greater than 0.2 mm, and less than 40 mm.

11. The apparatus according to claim 10, wherein a surface of the illuminator is greater than a cross-section of the object to be inspected.

12. The apparatus according to claim 1, wherein the object has, at least partially, non-transparent walls.

13. The apparatus according to claim 1, wherein a shutter device is arranged between the illuminator and the imaging monitor.

14. A method for inspecting objects which have an opening, wherein the objects are transported by a transport conveyor along a predetermined transport path and at least one region of an inner wall of the object is monitored by an imaging monitor through the opening of the objects, wherein the imaging monitor is configured for capturing spatially resolved images, wherein the apparatus has an illuminator configured to illuminate at least one region of the inner wall wherein the illuminator is arranged between the imaging monitor and the object, wherein an imager is focused in the monitoring direction such that the pupil region and/or focal point is located in the center of a transit region of the illuminator, wherein the object to be inspected is a can having a non-transparent base and side walls, and wherein a beam path extending from the object towards the monitoring device pass through the transit region and the transit region is configured as a hole in the illumination device and has a diameter which is between 1 mm and 20 mm.

15. The method according to claim 14, wherein a pupil of the imaging monitor is arranged in front of the imaging monitor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further advantages and embodiments are disclosed by the appended drawings.

(2) In the drawings:

(3) FIG. 1 shows an apparatus for inspecting containers according to the internal prior art in the name of the applicant;

(4) FIG. 2 shows an apparatus according to the invention for inspecting objects in a first embodiment;

(5) FIG. 3 shows an apparatus for inspecting objects in a second embodiment;

(6) FIG. 4 shows an apparatus for inspecting objects in a third embodiment;

(7) FIG. 4a shows a detail of a funnel-shaped shutter element;

(8) FIG. 5 shows an apparatus for inspecting objects in a fourth embodiment;

(9) FIG. 6 shows an apparatus for inspecting objects in a fifth embodiment; and

(10) FIG. 7 shows a representation to illustrate the principle of a pupil arranged in front.

DETAILED DESCRIPTION OF THE DRAWING

(11) FIG. 1 shows an apparatus 100 according to the internal prior art in the name of the applicant for inspecting cans. In this case the reference numeral 10 relates to the object to be inspected and in particular a can. The reference 4 designates a monitoring device which is arranged above the can in the longitudinal direction L of the can 10. In this case this monitoring device 4 is focused on a pupil region P which is located between the can 10 and the monitoring device 4. In other words the origin of the angle of view is located between the monitoring device and the object to be inspected.

(12) The monitoring device has a plurality of light sources 110, for example LEDs, which are arranged here in a ring around the optical axis O. During illumination of the object 10 reflections can occur, which in turn strike the image capturing device 4.

(13) FIG. 2 shows an apparatus 1 according to the invention for inspecting cans in a first embodiment. Here too a monitoring device 4 is provided, which has an objective 42. This objective is oriented or set in such a way that a focus or a pupil Z occurs between the objective and the can 10 to be inspected. The reference S designates the light beams emanating from the object. These light beams are collected by the objective and are imaged in a spatially resolved image on the objective image side. The reference 10c designates an opening of the object or of the can, through which monitoring and also illumination takes place.

(14) The reference 6 designates an illumination device which is arranged in a plane E between the monitoring device 4 and the can 10. It will be recognised that the illumination device is designed as a flat element which, however, has a larger cross-section than the object 10 to be inspected. In particular the cross-section of the flat element perpendicular to the optical axis is greater than the cross-section of the object perpendicular to the optical axis. This illumination device 6 emits in particular diffuse light, so that the inner wall 10b and also the base 10a are uniformly illuminated by the illumination device 6. In this way the illumination device is arranged very close to the can 10 and can illuminate the can completely in a particularly favourable manner. Furthermore, the illumination device may be suitable, for example in the case of open cans, for illuminating the flange thereof.

(15) Furthermore, the illumination device 6 has a transit region or a through opening 62 through which beams can pass. On the one hand this through opening 62 is located in a region of the optical axis, and on the other hand the opening is selected as large that the pupil or the focus can be placed in this opening. In this way a complete image of the inner region of the can 10 can be captured.

(16) The reference numeral 2 designates a transport device which transports the objects 10 in the transport direction T. In the variant shown in FIG. 2, this transport takes place in a straight line. The monitoring device 4 preferably includes an image capturing device, which produces an image in each case when the can 10 is located directly below the monitoring device 4, preferably when an axis of symmetry of the can 10 coincides with the optical axis O of the image capturing device.

(17) The reference numeral 2 designates a transport device which transports the objects 10 in the transport direction T. In the variant shown in FIG. 2 this transport takes place in a straight line. The image capturing device 4 preferably produces an image in each case when the can 10 is located directly below the image capturing device 4, preferably when an axis of symmetry of the can 10 coincides with the optical axis O of the image capturing device.

(18) The diffuse light from the illumination device results in the object or the can being uniformly illuminated. If the monitoring device has a specific type of protection (for example with regard to environmental influences such as dust, water and the like), it is also possible to cover the through opening 62, for example by means of a transparent glass or plastic pane. However, in this way dust in the region of the through openings or also scratches on this pane could lower the contrast in the camera image due to the light being scattered on the scratch or on the dust in the region of the through opening.

(19) In order to prevent this from occurring in this embodiment it would also be possible to use a suitable opaque shutter described in greater detail below between the through opening and the objective. In this case, as described in greater detail below, it is possible that the part of such a funnel-shaped shutter directed towards the illuminating surface is mirrored in order to be able to compensate for a possible brightness gradient which could be produced at the through opening.

(20) FIG. 3 shows a further embodiment of the apparatus according to the invention. Whilst in the embodiment illustrated in FIG. 2 the illumination device is an active or self-illuminating element, in the embodiment illustrated in FIG. 3 it is a passive element which is illuminated by two light sources 64. These two light sources 64 here are arranged above the illumination device in the direction of the optical axis O and thus illuminate the illumination device 6 from above. In the embodiment shown in FIG. 3 it is possible that the illumination device reflects light in all directions. However, it would also be possible that the illumination device itself is designed for instance in the manner of a partially transparent mirror, so that light is not radiated upwards, but only downwards.

(21) FIG. 4 shows an embodiment similar of the embodiment shown in FIG. 3. However, an optical shutter 12 is additionally provided here. This can than be designed as a funnel-shaped element and in particular could protect the image capture against scattered light. In this case it is possible that an outer surface 12a of this shutter is mirrored in order thus, as mentioned above, to increase the contrast. This shutter device is preferably designed as an optically opaque shutter. FIG. 4a shows a representation of this funnel-shaped element 12.

(22) FIG. 5 shows a further embodiment of the apparatus according to the invention. In this embodiment the illumination device 6 is luminous at both ends, that is to say it illuminates both upwards and also downwards. Here too, it would again be possible that upwardly exiting light is kept away from the image capturing device.

(23) In the embodiment shown in FIG. 6 an illumination device 64 is again provided, which couples light laterally into the illumination device 6 by means of an incoupling element 68. The illumination device 6 in turn emits diffuse light in the direction of the object 10 to be inspected.

(24) FIG. 7 illustrates the principle described here of the pupil arranged in front or the focal point arranged in front. The image capturing device here has two objective components 42a, 42b, which in this case are arranged one after the other along the optical axis. This arrangement provides that the entire optical unit has two focal points, wherein here a focal point Z is arranged upstream of the objective component 42b. The beams originating from the base 10a and the side wall 10b of the object are imaged by means of the objective component onto an image capturing element (not shown). The reference a designates the angle of view, and the reference Z here designates the location or intersection point of the angle of view a.

(25) In this case the light beams S, which are emitted by the object and reach the monitoring device, are shown at least partially. The characteristic of the monitoring device 42a/42b requires that the light beams which enter it are concentrated and focused through a location Z outside the monitoring device. Other light beams emanating from the object do not enter the monitoring device. The light beams S on the object side are imaged into a spatially resolved image on the image side in the monitoring device.

(26) The applicant reserves the right to claim all the features disclosed in the application documents as essential to the invention in so far as they are individually or in combination novel over the prior art. Furthermore it is pointed out that features which may be advantageous per se have also been described in the individual drawings. The person skilled in the art recognises immediately that a specific feature described in a drawing may also be advantageous without the incorporation of further features from this drawing. Furthermore the person skilled in the art recognises that advantages may also result from a combination of several features shown in individual drawings or in different drawings.

LIST OF REFERENCES

(27) 1 apparatus

(28) 2 transport device

(29) 4 monitoring device

(30) 6 illumination device

(31) 10 object to be inspected, can

(32) 10a base

(33) 10b inner wall

(34) 10c mouth

(35) 12 shutter

(36) 12a outer wall of the shutter

(37) 42 objective

(38) 62 through opening

(39) 64 light sources, illumination device

(40) 68 incoupling element

(41) 100 apparatus

(42) 110 light sources

(43) E plane

(44) O optical axis

(45) Z pupil region

(46) P transport direction

(47) S light beams

(48) L longitudinal direction

(49) a angle of view