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(11) | EP 2 119 511 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Apparatus and system for classifying products |
| (57) A system for classifying products (11,12), for instance fruits or vegetables, more
particularly cucumbers, with electromagnetic radiation, for instance visible light
in combination with adjacent wavelength regions, during conveyance in substantially
horizontal conveying direction, wherein the system comprises a first conveyor (10)
and a second conveyor (20) each having parallel carrier belts (100,200); a first camera
system (C1) directed to the first conveyor (10) and configured for making at least
one first image of first parts of the products (P1); a second camera system (C2) directed
to the second conveyor (20) and configured for making at least one second image of
at least second parts of the products (P2) which, on the first conveyor (10), were
covered by the carrier belts (100) thereof; a computer (500) configured for composing
the first image and the second image to form a representation of the entire surface
of each product, and for characterizing and classifying the products.
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[0001] The present invention relates to a system for classifying products, for instance fruits or vegetables, more particularly cucumbers, with electromagnetic radiation, for instance visible light in combination with adjacent wavelength regions, during conveyance in substantially horizontal conveying direction T.
[0002] Such a system is known from US5751833. In this specification, it is elucidated, in particular with reference to Figs. 5, 7, 8, 9 and 32 of this document, how products to be classified and sorted, and which are transported with one belt conveyor, are fed along a station with a system of cameras so that pictures are taken of products either rolling over the belt (Fig. 5) or being stationary on the belt (Figs. 7, 8, 9, 32), wherein each picture gives a large part of the surface of such a product, wherein all pictures taken at different angles by the various cameras and for different positions of the rolling products are composed by a processing unit to form a complete image, i.e. an image of the entire surface of such a product. More particularly, the belts are mutually arranged such that a channel-shaped conveying track is formed, suitable for conveyance of substantially round products lying one behind the other, such as, for instance, apples.
[0003] In this document, in Fig. 32, a further, second belt conveyor is shown, at a small angle to, and substantially in the direction T in line with the earlier-mentioned belt conveyor, having first and second carrier belts, respectively, for these two successive conveyors, while the second carrier belts are in line with the first and, in turns, in the intermediate spaces of the first. These first and second carrier belts are separately driven to effect differences in velocities to thus subject products to an additional operation of mutual positioning, more particularly for slowing the products down. Needless to say, the system with cameras is arranged before transfer to the second conveyor, to take pictures only at the location of the first conveyor where the products are sufficiently far apart.
[0004] In case of products that roll less easily, mostly because they have a very unround form, for instance cucumbers, or also paprika's or pears, the above-described system will not suffice.
[0005] In particular elongated products, such as cucumbers, will find insufficient support on such a narrow track, the result being that often, they will fall between the belts or sideways from the belts.
[0006] In the combination of stationary products and a wider net-shaped support, in proportion, considerable parts of the surface will be missed.
[0007] For instance, the products will have to be supported with more belts or with a tighter net so as not to fall between the mazes of the conveyor. Also, movements can occur that are so unexpected that the products fall from a side of the conveyor. Further, with such a support, the larger extent of covering is a drawback so that, when taking pictures, parts of the surface can be missed. A further drawback, in particular for very delicate fruits such as pears is that they may become damaged.
[0008] From the perspective of the currently very high quality requirements, the processing and treatment as mentioned hereinabove has drawbacks.
[0010] With it, in a simple manner, a manner of supplying products is obtained with which products can be picked up and processed, for instance packed, in a well-defined position. Maintaining the orientation and position of each product further implies that considerably less damage will occur. Here, for the purpose of classifying, a complete image of the product is still obtained without the product having to undergo relative displacement with respect to the carrier belts supporting the product.
[0011] In further exemplary embodiments, the present system can be characterized:
in that the representation of each product comprises a visually visual image;
in that the representation of each product comprises an image in at least one preselected wavelength region, for some products for instance, classification based on observation in wavelengths outside the visually visible electromagnetic spectrum can yield better results;
in that the carrier belts of the first and the second conveyor compose a virtually horizontal surface, for instance for conveying cucumbers;
in that the carrier belts of the first and the second conveyor compose an undulating surface with a relief of several channel-shaped conveyor tracks extending side by side in the conveying direction T, which may be of advantage for products that are rounder;
in that at least one of the two conveyors comprises product separating elements with which the orientation and the position of the products conveyed with said conveyor can be fixed;
in that the product separating elements are provided at a predetermined pitch distance on at least one carrier belt;
in that the carrier belts are strip-shaped; and/or
in that the carrier belts are cord-shaped.
[0012] In the following, the present invention will be described in further detail with reference to a drawing, wherein:
Fig. 1 presents a schematic side view of the system according to the invention;
Fig. 2 presents, in detail, a bottom view of an embodiment of the invention;
Fig. 3 provides a schematic perspective view of a further exemplary embodiment of the present invention wherein the conveyor is channel-shaped; and
Fig. 4 presents a view similar to that of Fig. 4, where products are separated by separating elements.
[0014] In Fig. 1, products P1, P2, for instance cucumbers in side view, are conveyed in conveying direction by two endless conveyors 10 and 20, respectively. Through a drive for each conveyor 10, 20, for instance schematically indicated end wheels 11, 21, a rotational direction of R1 and R2, respectively, will be followed. With a system of cameras C0, C1 and C2, images are made of the passing products P. With C0 and C1, images are made, both from above and from below, with C2 only from below. As will be elucidated hereinafter on the basis of Fig. 2, with a processing unit or computer 500, these images will be composed to form complete images of all these products P.
[0015] In Fig. 1, the cameras C0, C1 and C2 are indicated in a highly schematic manner. More particularly, several cameras can be used, for instance cameras for special wavelength regions or also auxiliary means such as mirrors can be used to obviate, upon lighting, possible formation of shadows, and therefore incomplete views. It will further be clear to the skilled person that for the elements of such a system, which are also understand to include lighting elements such as light sources, well-determined distances and angles can be set. With suitable programs, the computer 500 will be able to compose the recorded pictures or images to form the above-mentioned complete images. More particularly, the images involve parts of the surface of each product. Thus, with all pictures or images that are made, a representation of the entire surface of each product can be composed with the system mentioned. With special selections of wavelengths, for instance by means of lighting, or also by means of choice of filters, representations of the entire surface in preselected wavelength regions can be composed. Such settings enable recording of properties, features and characteristics of such a product with this selected setting. Upon further treatment and processing, these properties, features and characteristics can be suitably used, for instance when sorting to particular characteristics.
[0016] More particularly for the view from below, on the part of the first conveyor 10, parts p10-p14 of a product are observed at that position, numbered P1, and parts p20 - p25 of the same product are observed at its position on the second conveyor, numbered P2. The parts p10 - p14 and p20 - p25 can be combined in the computer as described hereinabove. When using specific wavelengths, representations can be composed, for instance in the visual field or in a specific wavelength region, such as for instance infrared, near infrared, ultraviolet or a still further part of the electromagnetic spectrum.
[0017] In Fig. 2, the transfer 300 between the two successive conveyors 10, 20 is shown in greater detail from below. A product P1, for instance a cucumber, is located on the first conveyor 10, and a second similar product P2 on the second conveyor 20. As indicated, the products are conveyed in the direction T. Both conveyors 10, 20 have conveying surfaces which are composed of strips or belts, 100, 200, respectively. In this view, the last part of a belt cannot be seen, but instead thereof views of parts of the respective end wheels 11, 21. Further, a transfer portion 300 is shown where the belts 100, 200 run virtually side by side, and in this exemplary embodiment run between one another, so that the products P end up very gradually from the first onto the second conveyor 10, 20, respectively, and the initial position and orientation the product P had on the first conveyor 10 remains intact.
[0018] As the initially taken position or orientation remains the same, it has appeared that the images that are made by the cameras C0, C1, C2 link up with each other very well and that accordingly, suitable complete images as elucidated hereinabove can be obtained and composed.
[0019] It will be clear to all skilled in the art that when a system of belts, cords or strips is used, several configurations are possible and suitable. For instance, the belts 100 of the conveyor 10 can be located between two outer belts 200 of the conveyor 20 as is indicated in Fig. 1. In this elaboration, the belts 100, 200 can be the only four belts, at sufficient intervals, and thus be sufficient and suitable for elongated products such as cucumbers. Further, the belts can have all sorts of forms, from flat strips or tapes to cords with a very course surface. Furthermore, suitable plastic materials can be chosen, for instance easily cleanable materials, or materials with special properties with regard to strength, for instance difficultly deformable materials, with which almost flat conveying surfaces are obtained also when conveying products.
[0020] In Fig. 3, a further exemplary embodiment of the present invention is shown, where a system of belts is used so that a channel-shaped first endless conveyor 10 with belts 110, 120 and a second endless conveyor 20 with belts 210, 220 are obtained, while a suitable channel angle 400 is selected and utilized, depending on, for instance, the type of products P and the positioning thereof, in the case of apples or pears for instance, where it is of importance that the angle is sufficiently acute to support the product in the channel to prevent rolling or sliding, or with pears to always position these in their longitudinal direction. Further, in the Figure, for the first conveyor 10 rollers 40, 41, 50, 51 are indicated over which rollers run the belts 110 and 120, and, for the second conveyor 20, the rollers 50, 51, 60, 61. It is clear that the rollers 50, 51 are joint rollers and also form a transfer area. The rotational directions R110, R120, R210, R220 result in the conveying direction T.
[0021] In Fig. 4, a further similar exemplary embodiment is represented where the products P are separated by product separating elements 70. These will be used especially upon conveyance of very smooth and round products that can change position and orientation very easily and thus provided images that can only very difficultly be combined into suitable combinations. In this Figure it is further indicated that the product separating elements 70 are provided at fixed intervals and thus define conveying positions with well-defined pitch distances. It will be clear to all skilled in the art that these elements 70 can be connected to the belts or strips 110, 120, 210, 220 in various manners, or even be detachable and movable so that the pitch distances are settable.
[0022] Using a system according to this invention is very suitable not only for composing the above-mentioned complete images and representations in a simple and secure manner. A further particularly great advantage has appeared to be transferring, with a head or hand of a robot, products which, during conveyance, have kept their orientation and position, more particularly their relative position. In the case of cucumbers for instance, by a suitable choice of interval and number of belts, a cucumber can be directed such as for instance described in another application of applicant, EP 07017714.2. The situation shown there is that of, for instance, the second conveyor where the cucumbers have kept their orientation and position according to the present invention. The accumulation of products obtained at the end of such a conveyor can then be taken up as a whole by a suitable robot head and be placed into a packing unit.
- a first conveyor (10), which extends in the horizontal conveying direction (T) and which has at least two endless, substantially parallel, first carrier belts (100; 110, 120) for forming a first at least single conveying track with intervals (102) between the first carrier belts (100; 110, 120),
- a first camera system (C1) directed to the first conveyor (10) and configured for making at least one first image of first parts (P10, P11, P12, P13) of the products (P1, P2) which are visible during conveyance by the first conveyor (10), unlike second parts which, through their location and position on the first carrier belts (100), are covered,
- a second conveyor (20) which extends in the horizontal conveying direction (T) in line with the first conveyor (10) and which has at least two endless, substantially parallel second carrier belts (200; 210, 220) for forming a second at least single conveying track in line with the first at least single conveyor track, wherein between the second carrier belts second intervals (202) are located,
- a transfer portion (300) configured for transferring the products from the first conveyor (10) onto the second conveyor (20), wherein in the transfer portion (300) at least one carrier belt (100; 200, respectively) of one conveyor (10; 20, respectively) is in line with an interval (202; 102, respectively) of the other conveyor (20; 10, respectively), such that in use, during transfer from the first conveyor (10) onto the second conveyor (20), the products (P1, P2) take and hold the same positions with respect to carrier belts (100, 200) of the two conveyors (10, 20), so that the second parts are visible when a product is located on the second conveyor (20),
- a second camera system (C2) directed to the second conveyor (20) and configured for making at least one second image of at least the second, then visible, parts (P20, P21, P22, P23, P24, P25) of the products (P1, P2) during conveyance by the second conveyor (20),
- a computer (500) configured for processing the images, for composing the at least one first image made upon conveyance by the first conveyor (10) and the at least one second image made upon conveyance by the second conveyor (20) to form a representation of the entire surface of each product (P1, P2) and for characterizing and classifying the products (P1, P2).
REFERENCES CITED IN THE DESCRIPTION
This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.
Patent documents cited in the description