DE102010037448A1 - Method and device for detecting empties containers - Google Patents

Abstract

The invention relates to a method for detecting empties containers in empties return machines, the empties container being illuminated and detected by means of an optical recognition unit, so that at least one identification feature identifying the empties container is determined from the determined image data, the empties container being positioned in front of a reference sample area and then a top view of the empty container and its surroundings is generated, an at least partial contour of the empty container being determined as a function of a deviation of the detected pixel values from a predetermined threshold value.

Description

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 the 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, for example, comprise CCD cameras as described in US Pat DE 10 2008 006 382 A1 are known for the detection of the material and the filling state of the empty container. 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, which is disposed between the 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 contour information depends on the number of raster pixels captured 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, provision may be made for pixel values of the reference pattern to be stored in a reference data memory in a first step, preferably before the detection process. 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 empties container is carried out by a number of contour points of the empty 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 empties 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.

Show it:

1 1 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,

2 a schematic plan view of the empty container according to 1 .

3a a section of the supervision according to 2 in a detection field of the Empties container, wherein the empties container consists of a plastic material, and

3b a section of the supervision according to 2 in a detection field of the empties 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, the empty containers 1 to collect in a container and to print the user of the reverse vending machine a receipt with the corresponding deposit value.

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

For detecting a shape or contour of the empty container 1 the device essentially comprises an optical detection unit 2 as well as a lighting unit 3 on, on a common side regarding the empty container 1 are arranged. The lighting unit 3 may comprise a plurality of LED lights having a detection area 4 in which the empties container 1 is arranged, illuminate. The optical detection unit 2 may comprise an image sensor or a camera, which is adapted to a supervisory image of the detection area 4 to create. 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 empty container 1 is on a support surface 5 , which may for example be designed as a means of transport (conveyor belt) positioned. The bearing surface 5 forms a reference pattern surface, for example, a printed reference pattern 6 see, see 2 , The reference pattern area 5 forms a background for the empty container 1 and is on one of the optical detection unit 2 facing away from the empties container 1 arranged. The reference pattern 6 extends over a larger area than the empty container 1 and extends at least over the entire coverage area 4 , The optical detection unit 2 and the reference pattern 6 allow the capture of regulatory images, by means of which as a feature identifier a feature or a contour feature of the empty container 1 can be determined.

How out 2 can be seen is the reference pattern 6 by a stripe pattern with a number of alternating black stripes 7 and white stripes 8th educated. These stripes 7 . 8th extend substantially perpendicular to a longitudinal axis of the empty container 1 or perpendicular to a longitudinal side 1' of the empty container 1 ,

According to a first embodiment of the invention, pixels of the detection area 4 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 or white stripes 8th 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 may be just above a light intensity value for the black stripes 7 lie so that when falling below the threshold value by the pixels these are recognized as lying on the black strip pixels P1. This ensures that along the black stripes 7 the reference pattern area 5 Pixels P1 (background image data) can be determined, of which in 2 only a few are shown by way of example.

Due to a bright surface of the empty container 1 or not complete transparency of the same are those on the surface of the empty container 1 determined pixels above the threshold, so that the empty container 1 representative pixels P2 (empty container image data) are defined, of which in 2 by way of example only a few are shown.

At a transition or boundary between the "black" pixels P1 and the "white" pixels P2, pixels P3 result, which are illustrated in FIG 2 are shown quadratically. These pixels P3 form the contour of the empty container 1 , The feature of the empty container 1 is thus recognized, the empty container 1 can be transported within the reverse vending machine and a corresponding deposit amount credited.

According to an embodiment of the invention, not shown, in the optical detection unit 2 a bar code reader can be integrated, so that in addition also one on the label of the empty container 1 applied bar code is detectable. The device preferably has a rotary member for aligning the bar code in the direction of the optical recognition unit 2 , To this It can be ensured that by reading the bar code, an empty container 1 has been obtained.

Optionally, the bar code reader also outside the optical detection unit 2 be arranged.

According to a further embodiment of the invention, in the detection area 4 located pixels P1 of the reference pattern 6 be stored in advance as reference pixels in a reference data memory. These reference pixels are captured, if not yet an empty container 1 on the support surface 5 rests. This results in a number of maximum reference pixels Nmax.

In a capturing process in which the empty container 1 on the support surface 5 is positioned, is a supervisor image with pixels of the detection area 4 detected, wherein the pixels exceeding the threshold 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 be determined as it is in 2 is shown. 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 takes place 1 in that a difference is formed between the reference pattern 6 representative pixels of a first supervisory image that without empty container 1 and in a second supervisory picture with empties container 1 have been determined.

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

How out 3a can be seen in a transparent empty container 11 made of plastic material, even rows of pixels P5 detected, while in a transparent empty container 11 ' From glass material, a series 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 preserved. This can thus be used as a criterion for the determination of an identification characteristic of the empties container which relates to the material 11 . 11 ' serve.

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

Optionally, certain characteristic contour points, such as corners, of the empty container 1 determined by the detection method described above. In the present embodiment, the strips 7 . 8th formed in a straight line. 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, to determine the background image data, pixels of the white stripes may also be used 8th be used. 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

1, 1 '

empty containers

2

optical detection unit

3

lighting unit

4

detection range

5

bearing surface

6

reference pattern

7

black stripes

8th

White Stripes

10

detection field

11, 11 '

empty containers

N1

Background pixels

nmax

maximum reference pixels

P

pixels

P1

black pixels

P2

white pixels

P3

Contour / border

P5

pixels

P6

pixels

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102008017233 A1 [0003]
• DE 102008006382 A1 [0003]

Claims (13)

Method for detecting empties containers in empties reverse vending machines, wherein the empties 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 empties container is determined, characterized in that the empties container ( 1 . 11 . 11 ' ) in front of a reference pattern area ( 5 ) and then from the empty container ( 1 . 11 . 11 ' ) and its surroundings, a supervisory image is generated, wherein, as a function of a deviation of the detected pixel values from a predetermined threshold value, an at least partial contour (P3) of the empty container (FIG. 1 . 11 . 11 ' ) is determined. Method according to claim 1, characterized in that the reference pattern surface ( 5 ) by a regular reference pattern ( 6 ) and that only those locally selected pixels are detected which are associated with pixels (P1) of minimum or maximum intensity and / or brightness of the reference pattern surface (FIG. 5 ) to match. 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) they are used as background image data and wherein when the threshold value of the pixel values falls below the same Empty container image data are determined, and that at a transition between the background image data (P1) and the empty container image data (P2) contour image data (P3) are determined, which is used as an identifier for the contour of the empty container ( 1 . 11 . 11 ' ) serve. Method according to claim 1 or 2, characterized in that in a detection area ( 4 ) (Nmax) of the reference pattern ( 6 ) are stored in advance as reference pixels in a reference data memory and that in a detection process, the thresholds exceeding pixels (N1) detected and these pixels are classified as background pixels, wherein by subtracting the background pixels (N1) of the reference Pixels (Nmax) the contour of the empty container ( 1 . 11 . 11 ' ) is determined. Method according to one of claims 1 to 4, characterized in that one of the contour (P3) of the empty container ( 1 . 11 . 11 ' ) included detection field ( 10 ) of the topographical image for compliance with the reference design ( 6 ) is checked to determine a transparency and / or color and / or material of the empties container ( 1 . 11 . 11 ' ). Device for detecting empties containers in an empties 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, characterized in that the empties container ( 1 . 11 . 11 ' ) between the optical detection unit ( 2 ) and a reference pattern area ( 5 ), the reference pattern area ( 5 ) a background for a through the optical detection unit ( 2 ) taken supervision image of the empties container ( 1 . 11 . 11 ' ) and that the reference pattern surface ( 5 ) such a reference pattern ( 6 ), that from the recorded supervisory image as the identification feature a shape feature of the empty container ( 1 . 11 . 11 ' ) is derivable. Device according to claim 6, characterized in that the reference pattern ( 6 ) is formed as a stripe pattern with a number of stripes of different brightness and / or color. Device according to Claim 6 or 7, characterized in that the strip pattern is formed by a sequence of black strips (1) arranged alternately in one direction ( 7 ) and white stripes ( 8th ) is formed at the same distance. Device according to one of claims 6 to 8, characterized in that the optical detection unit ( 2 ) is controlled such that an image sensor of the optical detection unit ( 2 ) in a distance of adjacent strips ( 7 . 8th ) given the grid, and that depending 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 ' ) is determinable. Device according to one of claims 6 to 9, characterized in that the lighting unit ( 3 ) on a reference pattern ( 6 ) facing away from the empties container ( 1 . 11 . 11 ' ) is arranged. Device according to one of claims 6 to 10, characterized in that the reference pattern ( 6 ) on a support surface ( 5 ) of the empties container ( 1 . 11 . 11 ' ) is applied. Device according to one of claims 6 to 11, characterized in that a bar code of the empties container ( 1 . 11 . 11 ' ) by one in the optical detection unit ( 2 ) integrated bar code reader or by means of an external bar code reader is detected. Device according to one of claims 6 to 12, characterized in that the Empty containers ( 1 . 11 . 11 ' ) is positioned such that longitudinal sides ( 11 . 11 ' ) thereof transversely to the strips ( 7 . 8th ) of the reference pattern ( 6 ).

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