WO2012031651A1

WO2012031651A1 - Method and apparatus for sensing empty packaging containers

Info

Publication number: WO2012031651A1
Application number: PCT/EP2011/003930
Authority: WO
Inventors: Lioubov Jokhovets; Reiner Seitz; Andreas Littel
Original assignee: Wincor Nixdorf International Gmbh
Priority date: 2010-09-10
Filing date: 2011-08-05
Publication date: 2012-03-15
Also published as: EP2614335A1; DE102010037448A1

Abstract

The invention relates to a method for sensing empty packaging containers in empty packaging return machines, wherein the empty packaging container is illuminated and is sensed by means of an optical recognition unit, so that at least one identification feature identifying the empty packaging container is ascertained from the ascertained image data, wherein the empty packaging container is positioned in front of a reference pattern area and then a surveillance image is generated for the empty packaging container and its surroundings, wherein an at least partial contour of the empty packaging container is determined on the basis of a discrepancy between the captured pixel values and the prescribed threshold value.

Description

Method and device for detecting

empty containers

The invention relates to a method for detecting empties containers in reverse vending machines, wherein the empties container is illuminated and detected by means of an optical detection unit, so that at least one identification feature identifying the empties container is determined from the determined image data.

Furthermore, the invention relates to a device for detecting empties containers in a reverse vending machine with a lighting unit for illuminating the empties container and with an optical detection unit for detecting at least one identification feature of the empties container.

From DE 10 2008 017 233 A1 a device for detecting empties containers in a reverse vending machine is known, which has two optical detection units. A first optical detection unit cooperates with a rotary member, by means of which the empty container can be rotated about its longitudinal axis. The first optical detection unit serves to locate an identification feature of the empty container, in particular a bar code of the same. After the empties container has been brought into an alignment position by means of the rotary member, the bar code can be detected by means of a second optical detection unit. If the identifier of the empties container is the same as the shape or contour, the two-stage optical recognition is not necessary. For this purpose, it is customary to provide an optical detection unit with a relatively high resolution, which generates an image of the empty container in a reflected light or transmitted light method, which is then evaluated in a corresponding evaluation unit. The optical detection units may include, for example, CCD cameras, as described in DE 10 2008 006 382 A1 for detecting the material and the filling state of the empties container. containers are known. In order to obtain a good result for the shape recognition of the empties container, it is necessary that a surface of the empties container is completely and uniformly illuminated by means of a lighting unit. For this purpose, the lighting unit has a relatively large surface, which, however, can easily become dirty and thus falsify the image acquisition. It requires a relatively large amount of computation or data for the extraction of the identification features characterizing the shape of the empty container from the image data. In addition, the lighting unit is relatively bulky, which increases the footprint of the device.

The object of the invention is therefore to provide a method and a device for detecting empties containers in reverse vending machines such that in a simple and secure manner, in particular a form of the empty container can be detected.

To achieve this object, the inventive method in conjunction with the preamble of claim 1 is characterized in that the empties container is positioned in front of a reference pattern surface and then from the empty container and its surroundings a supervisory image is generated, depending on a deviation of the detected pixel values a predetermined threshold, an at least partial contour of the empty container is determined.

The particular advantage of the method according to the invention is that a secure shape recognition of empty containers can be made relatively quickly and safely and with little effort. No computationally expensive algorithms are required. Furthermore, the requirements for the illuminance for the empties container to be detected are relatively low. The basic idea of the invention is to assign a reference pattern area to the empties container, so that pixels of the empties container and the reference pattern area are detected and set in relation to one another using an incident light method. The empty container between the -

is arranged as a background reference pattern surface and the optical detection unit, forms a disturbance in the recording of the reference pattern. This areal disturbance of the reference pattern is detected and used for the identification of a particular contour or shape of the empty container. Since the reference pattern is designed so that deviations are recognizable to an at least partially transparent before the same body, the data and computational effort for the contour detection of the empty container is relatively low.

According to a preferred embodiment of the method, the reference pattern surface is formed by a regular reference pattern. Furthermore, only locally selected pixels of the detection area are detected, which coincide with predetermined pixels, for example pixels of minimum or maximum intensity and / or brightness of the reference pattern area. By a change in intensity of the detected pixel, the contour of the empty container can be detected. It is thus sufficient to detect the detection area in a grid-like manner, brightness differences and / or intensity differences of the pixels pointing to the contour of the empties container. The data expenditure as well as the expenditure for the data processing can thus be kept low. The accuracy of the contour information depends on the number of captured raster pixels and the density of the regular reference pattern.

According to a development of the method according to the invention, the detected pixel values are compared with a predetermined threshold value. If the threshold is exceeded, these pixels are recognized as background image data. If the threshold value is undershot, these pixel values are recognized as empties image data. The boundary between the background image data on one side and the empties image data on the other side can serve as an identifier for the contour of the empties container. -

According to a development of the method according to claim 4, it may be provided that in a first step, and preferably before the detection process, pixel values of the reference pattern are stored in a reference data memory. For the purpose of detecting the empty container, it is positioned between the reference pattern surface and an optical recognition unit, so that subsequently the pixel values of the detection range exceeding a predetermined threshold value are detected. Since the pixel values lie below the threshold value at least in the region of the contour of the empty container, the contour of the empty container can be determined by subtracting the entire background pixels from the reference pixels.

According to a development of the invention, a trapped by the contour of the empty container detection field can be checked within the supervisory image for compliance with the reference pattern. As a result, advantageously a transparency and / or a color and / or a material of the empty container can be detected. Advantageously, a functional extension can be achieved with little effort.

To solve this problem, the device according to the invention in connection with the preamble of claim 6 is characterized in that the empties container is disposed between the optical detection unit and a reference pattern surface, wherein the reference pattern surface forms a background for a recorded by the optical detection unit supervisory image of the empty container, and in that the reference pattern surface has such a reference pattern that a shape characteristic of the empties container can be derived from the acquired supervisory image as the identification feature.

The particular advantage of the device according to the invention is that a contour of the empty container can be determined in a simple and secure manner. The identification of the empty container is carried out by a number of - -

ture points of the empties container, wherein the resolution depends on the type, shape and screening of the reference pattern.

According to a preferred embodiment of the invention, the reference pattern is formed as a stripe pattern having a number of stripes of different brightness and / or color. The stripe pattern is selected to have a different structure to the empty container in terms of light intensity. Advantageously, the contour of the empty container can thereby be determined relatively quickly by comparison.

According to a development of the invention, the stripe patterns are formed by a series of alternating black stripes and white stripes in one direction. This makes it possible to form "zebra stripes as a background surface, which enable effective contour recognition of the empty containers.

According to a development of the invention, the reference pattern is applied to a support surface on which the empty container is positioned. Optionally, this may also be a conveyor belt, by means of which the empty container is transported. Thus, no additional space is required by the reference pattern.

According to a development of the invention, a further optical recognition unit can be provided, which is able to detect a bar code as a recognition feature of the empty container. This advantageously makes it possible to detect an emptied container provided with a bar code. The additional shape recognition prevents the deposit of deposit money in reverse vending machines by supplying not associated with a container empties barcodes.

Further advantages of the invention will become apparent from the further subclaims. - -

Embodiments of the invention will be explained in more detail with reference to FIGS.

1 shows a schematic side view of a device according to the invention with a bottle-shaped empties container which is positioned on a conveyor belt and is detected by an optical detection unit, a section of the plan view according to FIG. 2 in a detection field of the empties container , wherein the empties container consists of a plastic material, and a section of the plan view of Figure 2 in a detection field of the empty container, wherein the empties container consists of a glass material.

A device for detecting empties containers 1 is integrated in a reverse vending machine, not shown, which is adapted to receive empty containers, possibly to sort different types of empty containers to collect the empties container 1 in a container and the user of the reverse vending machine a Bon with the appropriate deposit value.

The empty container 1 may be formed as a bottle, which is made of a transparent material, such as plastic or glass. customary Licher way, the empty container 1 has a label which is provided with a bar code as an identifying feature.

For detecting a shape or contour of the empties container 1, the device essentially comprises an optical recognition unit 2 and a lighting unit 3, which are arranged on a common side with respect to the empties container 1. The lighting unit 3 may comprise a plurality of LED lights that illuminate a detection area 4, in which the empty container 1 is arranged. The optical detection unit 2 may comprise an image sensor or a camera, which is designed to generate a supervisory image from the detection area 4. In the optical detection unit 2, a processing or evaluation device (CCD camera) can be integrated, by means of which captured image data can be further processed.

The empties container 1 is on a support surface 5, which may for example be designed as a means of transport (conveyor belt) positioned. The support surface 5 forms a reference pattern surface, which has for example a printed reference pattern 6, see Figure 2. The reference pattern surface 5 forms a background for the empty container 1 and is arranged on a side facing away from the optical detection unit 2 of the empty container 1. The reference pattern 6 extends over a larger area than the empty container 1 and extends at least over the entire detection area 4. The optical detection unit 2 and the reference pattern 6 allow capturing of oversight images, by means of which a feature or a contour feature of the empties container 1 as an identification feature can be determined.

As can be seen from FIG. 2, the reference pattern 6 is formed by a stripe pattern having a number of alternately arranged black stripes 7 and white stripes 8. These strips 7, 8 extend substantially perpendicular to a longitudinal axis of the empty container 1 or perpendicular to a longitudinal side V of the empty container 1. According to a first embodiment of the invention, pixels of the detection area 4 are detected and then sent for further processing. The resolution of the image sensor device can be chosen so that pixels (pixel values) in a grid of lines Z1, Z2, ... Zn and columns S1, S2, ... Sn are read out to form the supervisor image, the column width with the distance between two black stripes 7 and white stripes 8 matches. These lattice-like or grid-like detected pixels P are now compared with a predetermined threshold. The threshold value may be, for example, a light intensity value. For example, the threshold value may be just above a light intensity value for the black stripes 7, so that when the threshold value is undershot by the pixels, these are recognized as pixels P1 lying on the black stripe. This ensures that along the black stripes 7 of the reference pattern surface 5 pixels P1 (background image data) are determined, of which only a few are shown by way of example in FIG.

Due to a bright surface of the empty container 1 or incomplete transparency of the same are determined on the surface of the empty container 1 pixels above the threshold, so that the empty container 1 representing pixels P2 (empty container image data) are defined, of which in Figure 2 only few are shown.

At a transition or boundary between the "black" pixels P1 and the "white" pixels P2, pixels P3 are obtained, which are shown in square fashion for clarity in FIG. These pixels P3 form the contour of the empty container 1. The feature of the empties container 1 is thus recognized, the empties container 1 can be transported within the reverse vending machines and a corresponding deposit amount credited. -

According to one non-illustrated embodiment of the invention, a bar code reader can be integrated in the optical recognition unit 2, so that in addition a bar code applied to the label of the empty container 1 can also be detected. Preferably, the device comprises a rotary member for aligning the bar code in the direction of the optical detection unit 2. In this way it can be ensured that an empty container 1 has been obtained by reading the bar code.

If appropriate, the bar code reader can also be arranged outside the optical recognition unit 2.

According to a further embodiment of the invention, the pixels P1 of the reference pattern 6 located in the detection region 4 can be stored in advance as reference pixels in a reference data memory. These reference pixels are detected when no empty container 1 rests on the support surface 5. This results in a number of maximum reference pixels Nmax.

In a detection process in which the empties container 1 is positioned on the support surface 5, a supervisor image with pixels of the detection region 4 is detected, wherein the pixels exceeding the threshold value are classified as background image data. This number of background pixels may be N1, which is smaller than the maximum number of pixels Nmax. By subtracting the detected background pixels N1 from the maximum reference pixels Nmax, the contour P3 of the empty container 1 can be determined, as shown in FIG. As in the first embodiment of the invention, pixels are detected in a grid-like manner, adjacent pixels being at the same distance from each other. However, the determination of the contour of the empty container 1 is characterized in that a difference is formed between the reference pattern 6 representing pixels of a first supervisory image, which have been determined without empty container 1 and in a second supervisory image with empty container 1. - -

According to a further embodiment of the invention, the pixels can be detected in a predetermined, preferably in a close to the bottle neck region of the empty container 1 detection field 10 to determine the material and / or the color and / or the transparency of the empty container 1. There is a light intensity range of the pixels to a reference pattern 6, as already described above.

As can be seen from FIG. 3a, in a transparent empty container 11 made of plastic material, even rows of pixels P5 are detected, while in the case of a transparent empty container 1 'made of glass material, a row of arcuately arranged pixels P6 is detected. An empty container 11 made of plastic material preferably has thinner walls than a glass bottle 11 ', so that the regular structure of the reference pattern 6 is maintained. This can thus serve as a criterion for the determination of a material-related identification feature of the empties container 11, 11 '.

By light intensity and / or color comparison and the color of the empty container 1 or the question of whether it is a transparent or colored empties container 1 can be determined.

If appropriate, certain characteristic contour points, for example corner points, of the empties container 1 can also be determined by the detection method described above. In the present embodiment, the strips 7, 8 are rectilinear. Optionally, these may also have a serpentine or another shape or color. This depends on the shape and transparency of the empty container 1.

Alternatively, pixels of the white stripes 8 can also be used to determine the background image data. In this case, the threshold value has a relatively high brightness value, at which point the pixels are recognized as background pixels. LIST OF REFERENCE NUMBERS

I, 1 'empty container

2 optical detection unit

3 lighting unit

4 detection area

5 contact surface

6 reference patterns

7 black stripes

8 white stripes

10 detection field

I, 11 'empty containers

N1 background pixels

Nmax maximum reference pixels

P pixels

P1 black pixels

P2 white pixels

P3 contour / boundary

P5 pixels

P6 pixels

Claims

claims

1. Method for recording empties containers in empties

Automatic reverse vending machines, wherein the empty container is illuminated and detected by means of an optical detection unit, so that from the determined image data at least one identification feature identifying the empty container is determined, characterized in that the empties container (1, 11, 11 ') positioned in front of a reference pattern surface (5) and then from the empty container (1, 11, 11 ') and its surroundings a supervisory image is generated, wherein depending on a deviation of the detected pixel values to a predetermined threshold, an at least partial contour (P3) of the empty container (1, 11, 11 ') is determined.

2. The method according to claim 1, characterized in that the reference pattern surface (5) by a regular reference pattern (6) is formed and that only those locally selected pixels are detected with the pixels (P1) of minimum or maximum intensity and / or brightness of Reference pattern surface (5) match.

3. The method according to claim 1 or 2, characterized in that the individual detected pixel values (P) are compared with the threshold value, wherein when the threshold value is exceeded by the pixel values (P) the same as the background image data and wherein falling below the threshold value of the pixel values the same are determined as empty container image data, and that at a transition between the background image data (P1) and the empty container image data (P2) contour image data (P3) are determined as an identifier for the contour of the empty container (1, 11 , 11 ') serve.

4. The method according to claim 1 or 2, characterized in that in a detection area (4) located pixels (Nmax) of the reference In a detection process, the pixels exceeding the threshold value (N1) are detected and these pixels are classified as background pixels, whereby the background pixels (N1) are subtracted from a reference data memory as reference pixels. from the reference pixels (Nmax), the contour of the empty container (1, 11, 11 ') is determined.

5. The method according to any one of claims 1 to 4, characterized in that a of the contour (P3) of the empty container (1, 11, 11 ') enclosed detection field (10) of the top view is checked for conformity with the reference pattern (6) for Determining a transparency and / or color and / or material of the empty container (1, 11, 11 ').

6. Device for collecting empty containers in an emptied container

Automatic reverse vending machines with an illumination unit for illuminating the empties container and with an optical recognition unit for detecting at least one identification feature of the empties container, characterized in that the empties container (1, 11, 11 ') between the optical detection unit (2) and a reference pattern surface (5) is, wherein the reference pattern surface (5) forms a background for a taken by the optical detection unit (2) supervision image of the empty container (1, 11, 11 '), and that the reference pattern surface (5) has such a reference pattern (6) that the detected supervisory image as the identification feature a shape feature of the empty container (1, 11, 11 ') can be derived.

7. The device according to claim 6, characterized in that the reference pattern (6) is formed as a stripe pattern with a number of strips of different brightness and / or color.

8. Apparatus according to claim 6 or 7, characterized in that the

Stripe pattern is formed by a sequence of unidirectionally arranged black strips (7) and white strips (8) of equal spacing.

9. Device according to one of claims 6 to 8, characterized in that the optical detection unit (2) is driven such that an image sensor of the optical detection unit (2) in one of the spacing of adjacent strips (7, 8) predetermined grid the top view created, and that in dependence on a comparison between the determined image values and a light intensity threshold, a two-dimensional contour (P3) of the empty container (1, 11, 11 ') can be determined.

10. Device according to one of claims 6 to 9, characterized in that the illumination unit (3) on a reference pattern (6) facing away from the empty container (1, 11, 11 ') is arranged.

11. Device according to one of claims 6 to 10, characterized in that the reference pattern (6) on a support surface (5) of the empty container (1, 11, 11 ') is applied.

12. Device according to one of claims 6 to 11, characterized in that a bar code of the empty container (1, 11, 11 ') by a in the optical detection unit (2) integrated bar code reader or by means of an external bar code reader can be detected.

13. Device according to one of claims 6 to 12, characterized in that the empties container (1, 11, 11 ') is positioned such that the longitudinal sides (11, 11') thereof transversely to the strips (7, 8) of the reference pattern ( 6).