METHOD FOR SEPARATING AND CLASSIFYING WASTE, IN PARTICULAR PACKAGING

Abstract

Disclosed is a system and a method for classifying articles in a flow of articles to be separated, the flow of articles to be separated being installed on a conveying device, including: —an image acquisition member installed so as to be able to acquire at least one image of a portion of the flow of articles to be separated; —a first overhanging light source, which emits in the visible spectrum and illuminates the portion of the flow of articles to be separated, the at least one image of which is acquired by the image acquisition member; a classification member capable of classifying the articles of the portion of the flow of articles to be separated according to the acquired image; and at least one second light source, of a different nature than the first light source, allowing additional visual information to appear on the acquired image.

Claims

1. System for classifying objects in a flow of objects to be sorted, the flow of objects to be sorted being installed on a conveying device (1), said system comprising: a device (8) for acquiring an image in the visible spectrum installed so as to be able to acquire at least one image of a portion of the flow of objects to be sorted; a first light source (4), emitting in the visible spectrum, installed overhanging and illuminating said portion of flow of objects to be sorted, said at least one image of which is acquired by the image acquisition device (8); a classification device able to classify the objects in said portion of the flow of objects to be sorted according to said at least one image acquired; wherein the system further comprises at least one second light source (5, 6, 7), with a nature distinct from the first light source (4), allowing the appearance of additional visual information in the visible spectrum on said at least one image acquired; the characterization device further being adapted to classify said objects in said portion of the flow of objects according to said additional visual information.

2. The system according to claim 1, wherein said at least one second light source (5) emits an ultraviolet light allowing the appearance of fluorescence in the visible spectrum when an object in the portion of flow of objects reacts to the ultraviolet.

3. The system according to claim 1, wherein said at least one second light source (6, 7) emits a light in the visible spectrum, with a color and/or intensity distinct from the first light source (4), and oriented so as to illuminate, at an illumination angle distinct from the first light source (4), the objects in the portion of flow of objects illuminated by the first light source (4).

4. The system according to claim 3, wherein said at least one second light source (6, 7) is installed so as to define a main illumination axis forming an acute angle with a plane wherein the device conveying said flow of objects extends.

5. The system according to claim 4, wherein the second light source (6, 7) forms an angle of 30° to 45° with the plane in which the device conveying said flow of objects extends.

6. The system according to claim 1, further comprising a unit for taking off objects connected to the classification device, the take-off unit being configured to take off objects in accordance with predetermined characteristics, obtained by means of the classification device.

7. The system according to claim 6, wherein the take-off unit is a robotic gripping unit.

8. Method for classifying objects to be sorted, comprising the following successive steps: a) providing a flow of objects to be sorted; b) illuminating at least part of said flow with at least one first light source and one second light source concomitantly, the first (4) and second light sources (5, 6, 7) being of different natures, and at least one of the two sources comprising wavelengths in the visible spectrum, c) acquiring at least one image in the visible spectrum of said illuminated flow part, said second light source (5, 6, 7) allowing the appearance of additional visual information in the visible spectrum on said at least one acquired image; d) detecting at least one object in said acquired image; e) classifying said detected object according to the visual information acquired in said at least one image, and according to said additional visual information.

9. The method according to claim 8, wherein: the first light source (4) is a source of white light, and the second light source (5, 6, 7) is selected from a source of ultraviolet light, a source of monochrome light in the visible spectrum, or a mixture thereof.

10. The method according to claim 8, further comprising a step of classification by infrared, comprising: f) a step of irradiating at least part of the flow of waste by an infrared light source, g) a step of detecting the infrared spectrum reflected from the irradiated flow of step f), by means of an infrared sensor, h) a step of analyzing the infrared spectrum of step g) to classify the waste of said flow.

11. Waste sorting method, said method comprising the following successive steps: a) a step of implementing the waste classification method according to claim 8; and b) a step of automated waste sorting on the basis of the classification of step a), according to predetermined parameters.

12. The method according to claim 11, wherein step b) is implemented by means of a robotic take-off unit.

13. Sorting assembly comprising: a conveyor (1), said conveyor comprising an object classification zone and an object take-off zone, an object classification system according to claim 1, comprising a classification device positioned around or above said object classification zone.

14. Sorting assembly comprising: a conveyor (1), said conveyor comprising an object classification zone and an object take-off zone, a system for classifying objects in a flow of objects to be sorted, the flow of objects to be sorted being installed on a conveying device (1), said system comprising: a device (8) for acquiring an image in the visible spectrum installed so as to be able to acquire at least one image of a portion of the flow of objects to be sorted; a first light source (4), emitting in the visible spectrum, installed overhanging and illuminating said portion of flow of objects to be sorted, said at least one image of which is acquired by the image acquisition device (8); a classification device able to classify the objects in said portion of the flow of objects to be sorted according to said at least one image acquired; wherein the system further comprises at least one second light source (5, 6, 7), with a nature distinct from the first light source (4), allowing the appearance of additional visual information in the visible spectrum on said at least one image acquired; the characterization device further being adapted to classify said objects in said portion of the flow of objects according to said additional visual information, the object classification system comprising a classification device positioned around or above said object classification zone, wherein the sorting assembly is adapted to implement the method according to claim 8.

15. The method of claim 8, wherein in step e), the visual information acquired in said at least one image is the color and/or transparency and/or material thereof.

16. The method of claim 10, wherein the infrared light source of step f) is a source of light in the near infrared (NIR), and wherein the classifying of step h) is performed according to the material thereof.

17. The method of claim 11, wherein the predetermined parameters comprise the material, the color and/or the transparency of the waste.

18. The system according to claim 2, wherein said at least one second light source (6, 7) emits a light in the visible spectrum, with a color and/or intensity distinct from the first light source (4), and oriented so as to illuminate, at an illumination angle distinct from the first light source (4), the objects in the portion of flow of objects illuminated by the first light source (4).

19. The system according to claim 2, further comprising a unit for taking off objects connected to the classification device, the take-off unit being configured to take off objects in accordance with predetermined characteristics, obtained by means of the classification device.

20. The system according to claim 3, further comprising a unit for taking off objects connected to the classification device, the take-off unit being configured to take off objects in accordance with predetermined characteristics, obtained by means of the classification device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0097] FIG. 1 shows an example of an embodiment of the invention. It is the case of a conveyor 1 equipped with a robot and an analysis system with a zone 2 for identifying the objects and a gripping zone 3 for the robot.

[0098] FIG. 2 shows in more detail the analysis system of FIG. 1. It comprises zones 4 for emitting white light, zones 5 for emitting UV light (for example a spotlight or a strip light) and/or zones 6, 7 emitting monochrome light, identical or different, and a zone 8 for detecting visible light (for example a camera).

[0099] FIG. 3 Transparent plastic packages on a dark surface: a. visible light only—b. visible light+UV—c. UV only.

[0100] FIG. 4 Transparent plastic packages on a pink surface: a. visible light only—b. visible light+UV—c. UV only.

[0101] FIG. 5 Opaque/aluminum plastic packages on a dark surface: a. visible light only—b. visible light+UV—c. UV only.

[0102] FIG. 6 Opaque/aluminum plastic packages on a pink surface: a. visible light only—b. visible light+UV—c. UV only.

[0103] FIG. 7 Paper/cardboard on a dark surface: a. visible light only—b. visible light+UV—c. UV only.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0104] The embodiment described and the following examples that are associated therewith are given purely for illustration and must not be considered to limit the invention in any way.

[0105] According to a first embodiment of the invention, an object sorting assembly, for example for sorting waste, comprises a conveyor, such as a belt conveyor 1, moving a flow of objects to be sorted, a system for classifying the flow of objects and a sorting device for sorting the objects in a sorting zone 3 according to the classification thereof.

[0106] The classification system comprises an image acquisition device 8, a classification device for classifying the objects to be sorted according to at least one image acquired and at least two light sources 4, 5, 6, 7 as described below.

[0107] The flow of objects to be sorted is composed of a plurality of objects of various natures, such as objects to be recycled.

[0108] The objects to be recycled may in particular comprise aluminum objects, such as cans, or objects made from transparent and/or opaque polyethylene terephthalate (PET), such as plastic bottles, containers of household or hygiene products, but these examples are non-limitative and any object known in the field of the recycling objects and the processing of waste may be an object to be sorted within the meaning of the present invention.

[0109] The image acquisition device 8 is adapted to capture one or more images of a predefined zone 2 on the belt conveyor 1. Thus the image acquisition device 8 acquires, for a given instant, an image of the portion of flow of objects passing through the field of vision of the image acquisition device 8, here referred to as the object identification zone.

[0110] In this embodiment the image acquisition device 8 is a camera capturing images in the visible spectrum, but the invention is however not limited to a single type of camera, and may also use a photographic apparatus or any other device adapted for capturing images.

[0111] It is generally accepted that the visible spectrum corresponds to a range of wavelengths in vacuum ranging from 380 nm to 780 nm, however the camera used by the invention is not limited to this defined range, and the camera may in particular capture images going beyond this wavelength range, for example by also capturing ultraviolet light lying between 200 nm and 380 nm, and then a hyper-spectral camera is spoken of; or on the other hand going below this wavelength as long as the camera is adapted to capture usable images of the objects to be processed according to the illumination conditions described below.

[0112] The objective of the camera is to acquire an image of the portion of flow of objects making it possible to classify the objects visible in the image.

[0113] Classification means defining the shape, material or type of the object visible in the image.

[0114] Thus the image acquisition device 8 transmits the images acquired to the classification device, which detects and classifies the objects and, object by object, determines the sorting to be done. Then the classification device instructs the sorting device to execute the sorting according to the detection done.

[0115] To obtain a reliable image analysis, it is relatively important to define lighting adapted to the good visibility of the objects in the identification zone 2 corresponding substantially to the field of vision of the camera.

[0116] In practice, the classification device frequency comprises a classification gantry passing over the object conveyor. The camera can then be installed under the gantry or at a distance from the gantry, so that the identification zone 2 is defined as the zone extending under the classification gantry.

[0117] The identification zone 2 is illuminated with a main light 4, also referred to as the first light source 4.

[0118] This first light source 4 is not necessarily made from a single point of emission. In particular, the first light source 4 is generally adapted to provide uniform illumination over the identification zone 2. Thus it is possible to arrange a plurality of identical lights forming the first light source 4.

[0119] This first light source 4 is, in the first embodiment of the invention, a set of white lights 4 distributed overhanging the acquisition zone.

[0120] However, this first light source 4 is not necessarily white and may emit any other color, adapted to an image analysis after acquisition by an image acquisition device such as a camera in the visible spectrum.

[0121] The purpose of this first light source 4 is in particular to define relatively uniform lighting able to allow sharp and contrasted acquisition of the objects in the portion of the flow of objects in the field of vision of the camera while reducing the appearance of visual artifacts that could affect the analysis of the images acquired, such as shadows or reflections caused by the lighting.

[0122] In order to improve the classification of the objects present in the image acquired, a second light source 5, 6, 7 is added.

[0123] This second light source 5, 6, 7 is selected according to the materials that it is wished to identify, in particular in the portion of flow of objects analyzed.

[0124] This second light source 5, 6, 7 may be obtained by a light having a color distinct from the main light.

[0125] The examples described below illustrate in particular the results obtained by combining a first light source with a second light source 5 diffusing ultraviolet, as well as the visual improvement obtained according to the materials of the objects present in the portion of flow of objects analyzed.

EXAMPLES

Example 1: Irradiation with Combination of Visible and UV Lights on Waste of the Transparent Plastic Packaging Type

[0126] Equipment

[0127] Dark-colored support: 2 cm panel made from graphite expanded polystyrene;

[0128] Light-colored support: 2 cm panel made from extruded polyurethane;

[0129] White light: set of 4 LED lamps placed at the 4 corners of the panels, type GU10, 5 W, 400 lumens, warm white 2700-3000 K over 110°;

[0130] UV light: [0131] One 20 W black-light tube, 60 cm long (situated just below the bottom part of the photograph), [0132] One 15 W T3 mini-spiral fluocompact bulb (situated along the right-hand side of the photograph);

[0133] Image sensor: Photographic apparatus of the Panasonic Lumix type, DMC-PZ 100, automatic mode in MP4.

[0134] Results

[0135] Waste of the transparent plastic packaging type is disposed randomly on a dark support (FIG. 3) or on a light support (pink, FIG. 4). The waste is illuminated solely with white light (FIGS. 3a and 4a), a combination of UV light and white light (FIGS. 3b and 4b), or with UV light alone (FIGS. 3c and 4c).

[0136] It is observed that:

[0137] White paper and labels stand out more;

[0138] Transparent PET exhibits a white veil by fluorescence, which is all the more marked, the thicker is it; and

[0139] Fluorescence of transparent plastics is more visible on a dark non-reflective background.

Example 2: Irradiation with Combination of Visible and UV Lights on Waste of the Opaque Plastic Packaging Type

[0140] The same equipment as in example 1 is used for implementing example 2.

[0141] Waste of the opaque plastic packaging type is disposed randomly on a dark support (FIG. 5) or on a light support (pink, FIG. 6). The waste is illuminated with white light alone (FIGS. 5a and 6a), a combination of UV light and white light (FIGS. 5b and 6b), or with UV light alone (FIGS. 5c and 6c).

[0142] It is observed that: [0143] white paper and labels stand out more, and [0144] PE and PP do not really change color whereas other plastics are illuminated by fluorescence, exhibiting a discriminating character more advanced than simply white light.

Example 3: Irradiation with Combination of Visible and UV Lights on Waste of the Paper and Cardboard Type

[0145] The same equipment as in example 1 is used for implementing example 3.

[0146] Waste of the paper and cardboard packaging type is disposed randomly on a dark support (FIG. 7). The waste is illuminated with white light only (FIG. 7a), a combination of UV light and white light (FIG. 7b), or with UV light alone (FIG. 7c).

[0147] It is observed that:

[0148] White paper appears much whiter (by fluorescence).

[0149] The contrast between brown, white and grey cardboard is much greater.

CONCLUSIONS

[0150] Thus it is noted that adding an ultraviolet UV light source 5, in addition to visible light 4, for image recognition makes it possible to provide additional distinguishing characteristics for visual recognition and gives rise to an increase in the recognition performance in some sorting scenarios.

[0151] This is because illuminating objects by ultraviolet 5 makes it possible to add, by fluorescence, distinguishing pixels in the images acquired, which improves the efficacy of the image-analysis and object-classification methods.

[0152] The invention is however not limited to a second light source diffusing ultraviolet.

[0153] According to a particular embodiment of the invention, the second light source 6, 7 comprises a monochrome light in the visible spectrum, with a color different from white, for example green or red.

[0154] As with the main light, the second light source is not limited to a single emission point. Here the second light source consists of two light sources 6, 7, with identical optical characteristics, but opposite each other with respect to the flow of objects, or in other words each on one side of the identification zone 2.

[0155] This second light source 6, 7 is then diffused at an angle differing from the main emission angle of the first light source 4.

[0156] In particular, each emission point of the second light source 6, 7 is installed so that the main emission axis thereof forms an angle lying substantially between 30° and 45° with the normal to the support on which the objects of the portion of objects being analyzed are installed.

[0157] Main emission axis means the axis forming the center of the light beam emitted by the light source 6, 7.

[0158] The objective of the particular arrangement of this second light source 6, 7 is to allow the appearance of reflections on the objects, and in particular to color the edges of the objects, so as to reveal on the images acquired the borders of the objects in the color of the second light source 6, 7.

[0159] Thus, if the second light source is red, the borders of the objects of the identification zone will reflect the red color, this color being able to vary with the color of the material concerned, which relatively greatly facilitates the classification of the objects in the image acquired.

[0160] According to a particular embodiment of the invention, the second light source 6, 7 could have a color similar to the first light source but with a distinct emission intensity, for example with an appreciably greater illumination intensity, so that the borders of the objects will be over-illuminated.

[0161] It is also possible to combine the above embodiments, and in particular to define a classification system comprising a main light source 4, a second light source 6, 7 in the visible spectrum, for example with a color distinct from the main light source 4, and a third light source 5 emitting an ultraviolet light as previously described, this making it possible to combine the advantages described previously.

[0162] Moreover, it is possible to combine a second light source 5, 6, 7 and optionally an additional light source, for example an ultraviolet source and a light source in the visible spectrum, for example red or green, with illumination by infrared, or near infrared.

[0163] In the field of the sorting of objects, the technique of classification by infrared, or near infrared (better known by the term NIR), is well known to a person skilled in the art, and this technique of classifying the materials may be combined with the detection means described in the present invention.

[0164] The invention also relates to a method for classifying the objects in a flow of objects, comprising in particular a step of providing a flow of objects to be sorted, such as a flow of waste.

[0165] A step of illuminating an identification zone 2 through which at least a portion of the flow of objects is passing at a given instant is implemented.

[0166] The illumination is implemented by disposing a first light source 4 and a second light source 5, 6, 7 having a nature distinct from the first light source 4.

[0167] Then, by means of an image acquisition device 8, at least one image of said portion of the flow of objects is acquired at the given instant.

[0168] This image is transmitted to the classification device, which detects and classifies the objects present in the image. The double illumination disclosed previously makes it possible in particular: [0169] when the second light source is an ultraviolet source, to classify the materials by the fluorescence that can be produced on the objects in the flow of objects, as described in the previous examples; and/or [0170] when the second light source is a monochrome source of the spectrum in the visible range, for example red or green or any other visible color, to classify the objects in particular by improving the contours of these objects.

[0171] Thus the illumination step makes it possible to improve the result obtained at the classification step.

[0172] Next, depending on the classification of the objects present in the image acquired, the sorting device is instructed to proceed with the sorting of the objects detected, in accordance with normal practice in the sorting field.

[0173] Classifying the objects can thus be freely adapted for: [0174] classifying the materials constituting the objects of the acquired image, for example by evaluating the fluorescence during illumination by UV; and/or [0175] recognizing objects by implementing the image recognition method, in particular by identifying remarkable contours and shapes.

[0176] This recognition step can be implemented by conventional image recognition methods or machine learning methods, such as neural networks. In particular, convolutional neural networks are particularly effective for implementing object recognition in an acquired image.