Equipment for sorting items

Abstract

The present application provides a device for sorting objects, comprising: a transport mechanism (2) arranged to transport an object flow (4); a radiation source (8) configured to emit electromagnetic radiation in a first direction (10) for irradiating a detection area (12); a detection unit (14) configured to observe the detection area (12) along a second direction (16) and detect electromagnetic radiation reflected by at least one object located in the detection area (12); an analysis unit operatively connected to the detection unit (14) and arranged to determine transparency or reflection information; and a removal unit configured to remove objects from the object flow (4), wherein the removal of the objects is based on the analysis in the analysis unit.

Description

[0001] This application is a divisional application of the Chinese patent application with application number 201880063704.X and name “Classification Method and Apparatus” (based on the international patent application with international application date of September 3, 2018 and international application number PCT / EP2018 / 073639, which entered the Chinese national phase on March 30, 2020). Technical Field

[0002] The present invention relates to the field of object sorting. More specifically, the present invention relates to a method and apparatus for sorting off-belt objects. Background Art

[0003] Machines for inspecting and sorting bulk items supplied in a continuous stream typically include a feed unit, an optical system, and an analysis unit. The feed unit supplies a stream of items to be inspected continuously through a detection zone scanned by the optical system, which is in operative communication with the analysis unit. The analysis unit analyzes each individual item in the stream for one or more preselected properties, such as color, shape, and / or texture, or any combination thereof. Based on this analysis, the analysis unit can verify whether the inspected item meets specific criteria with respect to the observed properties, thereby classifying it.

[0004] A requirement for such inspection and sorting devices based on optical sensors and analysis devices is to correctly differentiate between optical information from the inspected object and optical information from the background.

[0005] WO 2014 / 013421 describes a device for inspecting objects, the device being provided with a transport mechanism, such as a conveyor belt or a chute, which is configured to transport a continuous stream of objects so that the stream of objects follows a free-fall path when leaving the transport mechanism, so that the stream of objects is fed in a single layer of objects along the free-fall path through a detection area; a radiation source, which is configured to irradiate the detection area; a detection unit, which is configured to optically scan the irradiated detection area; an analysis unit and a possible removal unit and also a background element, which is located behind the falling stream of objects, and from the position of the detection unit, the background unit is positioned so that the electromagnetic radiation beams from the radiation source impinge on the irradiation area of ​​the background element, and when these beams do not impinge on objects from the stream of objects, the detection unit only receives an image of the detection area of ​​the background element, and is characterized in that the background element is mounted so that the irradiation area and the detection area are separated from each other.

[0006] This device provides a solution for detecting products in a product flow without false product detection due to electromagnetic radiation reflected from the background, however it does not provide product sorting based on optical features and is not optimal for detecting dark products located in the product flow. Summary of the Invention

[0007] The object of the present invention is to provide an improved solution for the sorting of transparent objects located in a product flow as they leave a belt.

[0008] According to a first aspect of the present invention, this object and other objects are achieved by a method for sorting articles, the method comprising the following steps: a guiding step of guiding a continuous flow of articles from a transport mechanism directly into an unsupported path so that the flow of articles is fed along the unsupported path through a detection area; an irradiation step of emitting electromagnetic radiation along a first direction for irradiating the detection area, the emitted electromagnetic radiation extending in a direction orthogonal to the first direction to form a radiation band; an optical scanning step of optically scanning the detection area by observing the detection area along a second direction to detect electromagnetic radiation reflected by at least one article located in the detection area, wherein the first direction and the second direction are directions having a cross-section located in the detection area and forming an angle in the range of 3°-80° or 10°-80° relative to each other; an analyzing step of analyzing information from the optical scan; and a classification step of classifying items from the item flow based on analysis of transparency information or reflection information from the optical scan; wherein the analyzing step of analyzing the information from the optical scan includes analyzing the items based on the intensity, dispersion and optional texture of the radiation detected from the optical scan, and wherein the analyzing step of analyzing the information from the optical scan includes comparing the information with information in a lookup table and / or comparing the information with one or more threshold values.

[0009] According to one embodiment, said sorting step of sorting said objects further comprises sorting objects from the object stream in at least two different directions based on reflection information from an optical scan and / or based on an analysis of sorting data.

[0010] According to one embodiment, the analyzing step of analyzing information from the optical scan further comprises comparing electromagnetic radiation from illumination directly reflected by at least one item located in the stream of items with information in a lookup table and / or one or more threshold values ​​to determine transparency or reflectance information of the at least one item.

[0011] According to one embodiment, the analyzing step of analyzing information from the optical scan also includes comparing the intensity and spread of electromagnetic radiation from the illumination directly reflected by at least one item located in the item stream with information in a lookup table and / or one or more thresholds to determine the transparency or reflectance information of the at least one item.

[0012] According to a second aspect of the present invention, a method for sorting items is provided, the method comprising the following steps: a guiding step of guiding a continuous flow of items from a transport mechanism directly into an unsupported path so that the flow of items is fed along the unsupported path through a detection area; an irradiation step of emitting electromagnetic radiation along a first direction for irradiating the detection area, the emitted electromagnetic radiation extending in a direction orthogonal to the first direction to form a radiation band; an optical scanning step of optically scanning the detection area by observing the detection area along a second direction to detect electromagnetic radiation reflected by at least one item located in the detection area, wherein the first direction and the second direction have a cross-section located in the detection area and form an angle relative to each other in the range of 3°-80° or 10°-80°; an analyzing step of analyzing information from the optical scan; and a classification step of sorting items from the flow of items in at least two directions based on an analysis of transparency information or reflection information from the optical scan; wherein the analyzing step of analyzing the information from the optical scan comprises analyzing the information from the optical scan based on the intensity, dispersion and optionally geology of the radiation detected from the optical scan.

[0013] The following information, features and embodiments relate to the first and second aspects of the present invention.

[0014] In the present invention, the radiation source is a line radiation, i.e., when impinging on a flat surface, the radiation forms a radiation streak or line, which can be captured and observed at least via an image sensor. Furthermore, the radiation streak formed by the emitted electromagnetic radiation when impinging on the flat surface can be captured and observed at least via an image sensor. The radiation can be collimated or focused.

[0015] According to one embodiment, a measurement system includes a radiation source and a detector, preferably focused on the object plane. The detector measurement plane does not intersect the line illumination and has a cross-section in the object plane. This means that if no object is present in the system, very low radiation is detected by the detector, as the illumination and detection lines do not intersect in the void space.

[0016] The analysis step of analyzing the information from the optical scan may further comprise determining transparency by comparing electromagnetic radiation from illumination directly reflected by at least one article located in the article flow with a first threshold value to determine whether material is present in the detection area, and thereafter comparing electromagnetic radiation from illumination directly reflected by at least one article with a second threshold value to determine whether the material present is transparent and / or reflective, wherein the second threshold value is above the first threshold value, and thereafter setting the transparency information.

[0017] By using threshold levels to evaluate the presence of an object in the inspection area and determine the likelihood that the object is transparent, this can enable efficient classification and / or sorting of objects, such as for classification and / or sorting of transparent objects in glass inspection applications and other applications.

[0018] In connection with the present invention, the term classification data refers to data obtained during or resulting from a classification step for classifying items in a stream of items. An example of classification data is a specific classification, such as acceptable / unacceptable, or a classification value within a range (e.g., classification A is x1 to x2; classification B is x2 to x3, where x1 is a number), which can be formed based on a single measured parameter value or a combination of measured parameter values. Another example of classification data is a classification value (formed based on a single measured parameter value or a combination of measured parameter values); a classification value can be a single value or an array of values.

[0019] According to one embodiment, classification data (i.e., data obtained in a classification step for classifying items in an article flow or from a classification step for classifying items in an article flow) are used to classify individual items located in a product flow in at least two different directions. Additionally or alternatively, the classification data can be used in the same device or transferred to another device in order to perform multiple operations, such as sorting in a later stage, and for statistical analysis. In other words, individual classification data can be assigned to individual items through different steps in the material processing process and remain connected to the items, and optionally used at one or more stations in the material processing process. Additionally or alternatively, for statistical purposes, individual or large amounts of classification data can be processed in the same machine in which the classification data are determined, or in other devices, for example, arranged wired or wirelessly.

[0020] Additionally or alternatively, analyzing the information from the optical scan further comprises classifying the transparency of the material. Additionally or alternatively, analyzing the information from the optical scan further comprises classifying the degree of reflectivity of the material. Analyzing the information from the optical scan further comprises comparing the direct reflection to a third threshold to determine the likelihood that the material is transparent.

[0021] The step of analyzing the information from the optical scan may further comprise determining the height and / or height profile of the articles located in the stream of articles.

[0022] The step of analyzing the information from the optical scan may include comparing the information with information in a lookup table (LUT) and / or comparing the information with a threshold value. The lookup table may be a one-dimensional lookup table, a two-dimensional lookup table, or an N-dimensional lookup table. The dimensionality here means that the lookup table evaluates, for example, sampled representatives of N variables. A one-dimensional lookup table returns an output in response to only one input parameter, such as the intensity or dispersion of the detected radiation; that is, one output is returned for the LUT (intensity) and one output is returned for the LUT (dispersion). On the other hand, a two-dimensional lookup table returns an output in response to two input parameters (e.g., the intensity and dispersion of the detected radiation), and one output is returned for the LUT (intensity, dispersion).

[0023] Alternatively, the analyzing step of analyzing information from the optical scan may include the use of deep learning or the use of support vector machines.

[0024] The method may further comprise the step of optically scanning an area located on the background element where the line irradiation strikes the background element, wherein the step of analyzing information from the optical scanning comprises determining whether material is present in the detection area based on the information from the optical scanning of the area located on the background.

[0025] Optically scanning an area located on a background element enables detection of reflections of line illumination on the background element, which makes it possible to determine whether an object is present in the detection area based on the reflections from the background element, thereby enabling detection and sorting of even very dark objects located in an object flow, as well as distinguishing optically dark objects from optically transparent objects.

[0026] The step of optically scanning the area located on the background member and the step of optically scanning the detection area may be performed simultaneously with one camera.

[0027] Using one camera with its viewing area covering both the detection area and the area where the laser line located on the background elements hits the background elements is a cost-effective solution that also simplifies the analysis of the information from the scan.

[0028] The step of illuminating the inspection area may be performed by illuminating a plurality of lines for the plurality of inspection areas, and the step of optically scanning the inspection area may be performed by illuminating a plurality of measurement lines for the inspection area. The step of analyzing information from the optical scanning may then include the determined movement of the items in the stream of items.

[0029] By determining the trajectory of the articles located in the article stream, the ejection of the articles can be performed more accurately and better overall sorting and / or sorting can be achieved.

[0030] The plurality of line illuminations may have different wavelengths, wherein the step of analyzing information from the optical scan comprises determining optical and physical properties of items located in the stream of items.

[0031] Alternatively or additionally, the multiple line illuminations may have different polarizations. This may be beneficial for removing background radiation.

[0032] According to a third aspect of the present invention, there is provided a device for sorting and / or separating articles, the device comprising: a transport mechanism arranged to transport an article flow so that the article flow follows an unsupported path after leaving the transport mechanism, and the article flow is fed through a detection area along the unsupported path; a radiation source configured to emit a radiation band in a first direction for irradiating the detection area; a detection unit arranged to observe the detection area along a second direction and detect electromagnetic radiation reflected by at least one article located in the detection area; wherein the first direction and the second direction have a cross-section located in the detection area and form an angle in the range of 10°-80° relative to each other; an analysis unit operatively connected to the detection unit and arranged to determine transparency information by comparing electromagnetic radiation from illumination directly reflected by at least one article in the article flow with a lookup table or one or more thresholds to determine whether material is present in the detection area, and thereafter comparing electromagnetic radiation from illumination directly reflected by at least one article with a second threshold to determine whether the material present is transparent, wherein the second threshold is above the first threshold.

[0033] According to a fourth aspect of the present invention, there is provided a device for sorting and / or separating articles, the device comprising: a transport mechanism arranged to transport an article flow so that the article flow follows an unsupported path after leaving the transport mechanism, and the article flow is fed through a detection area along the unsupported path; a radiation source configured to emit a radiation band in a first direction for irradiating the detection area; a detection unit arranged to observe the detection area along a second direction and detect electromagnetic radiation reflected by at least one article located in the detection area; wherein the first direction and the second direction have a cross-section located in the detection area and form an angle relative to each other in the range of 3°-80° or 10°-80°; an analysis unit operatively connected to the detection unit and arranged to determine transparency or reflection information by comparing electromagnetic radiation from illumination directly reflected by at least one article in the article flow with at least one threshold value or a lookup table to determine whether the material present in the detection area is transparent, and thereafter setting the transparency or reflection information.

[0034] The detection unit may also be configured to sense electromagnetic radiation reflected by a location on the background element where the electromagnetic radiation from the radiation source impinges on the background element.

[0035] The apparatus may include a plurality of radiation sources configured to irradiate articles positioned in a stream of articles, the articles being positioned at a plurality of locations along the unsupported path.

[0036] The apparatus may further comprise a removal unit configured to remove objects from the flow of objects, wherein the removal of the objects is based on the analysis in the analysis unit.

[0037] According to at least one embodiment, the analysis unit is further arranged to determine transparency information by comparing electromagnetic radiation from illumination directly reflected by at least one item in the item flow with a first threshold or a lookup table to determine whether material is present in the detection area, and thereafter comparing electromagnetic radiation from illumination directly reflected by the at least one item with a second threshold or a second lookup table to determine whether the material present is transparent, wherein the second threshold is optionally located above the first threshold, and thereafter setting the transparency information.

[0038] It is noted that the invention relates to all possible combinations of features in the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The present invention will now be described in detail with reference to the accompanying drawings, which show currently preferred embodiments of the invention.

[0040] Figure 1 is a schematic perspective view of an apparatus according to an embodiment of the present invention.

[0041] Figure 2 is a schematic diagram of an apparatus according to another embodiment of the present invention, which includes three line irradiations.

[0042] Figure 3 is a schematic perspective view of an apparatus according to another embodiment of the present invention, which includes line illumination detection.

[0043] Figure 4 is a flowchart of a method according to an embodiment of the present invention.

[0044] Figure 5 is a diagram of electromagnetic radiation detected by a detector in a device according to an embodiment of the present invention.

[0045] Figure 6 is available Figure 2 Schematic diagram of the trajectory of an item in an item flow detected by a device.

[0046] Figure 7 is located according to Figure 3 Schematic diagram of a cross section of the electromagnetic radiation detected by the detector of the device.

[0047] As shown in the drawings, the sizes of layers and regions may be exaggerated for illustrative purposes and, thus, may be provided to illustrate the general structure of embodiments of the present invention. Like reference numerals refer to like elements throughout. DETAILED DESCRIPTION

[0048] Figure 1 An apparatus for inspecting articles in an article stream according to an embodiment of the present invention is shown. A conveyor belt 2 directs an article stream 4 into an unsupported path, here, a free-fall path 6. Although a conveyor belt 2 is used here to direct the article stream 4 into the free-fall path 6, any type of transport mechanism, such as a chute, may be used in accordance with the present invention. A radiation source (here, a line laser 8) radiates a laser line in a first direction 10 through a detection region 12. Although a laser line is used here, any type of radiation source (using focused electromagnetic radiation) may be used in accordance with the present invention. The detection region 12 is the area through which articles that have left the conveyor belt 2 travel in the free-fall path 6. The laser line may be substantially equal to the width of the conveyor belt 2 to ensure that all articles in the article stream 4 travel through the detection region 12 when the article stream 4 is directed from the conveyor belt into the free-fall path 6. A detector (here, a camera 14) detects radiation in a measurement plane that intersects the laser line in the detection region 12. The measurement plane may be substantially equal to the width of the laser line.

[0049] The first direction 10 and the second direction 16 are disjoint and have a cross section in a detection zone 12. The detection zone 12 is located off-belt and at a location where the stream of articles 4 exiting the conveyor belt 2 is in a free-fall path 6. If there are no articles in the detection zone 12, the laser beam will strike a portion of the background element that is not detected by the measurement plane that passes through the detection zone. Therefore, if no articles are present, no reflected electromagnetic radiation is detected, making it clear whether an article is present in the detection zone.

[0050] The angle between the first direction 10 and the second direction 16 is preferably in the range of 3°-80°, more preferably in the range of 5°-60°, more preferably in the range of 8°-40°, more preferably in the range of 10°-35°, more preferably in the range of 15°-30°, more preferably in the range of 20°-25°.

[0051] The wavelength of the emitted electromagnetic radiation is preferably in the range of 300 nm - 2000 nm, more preferably in the range of 400 nm - 700 nm.

[0052] Material properties of items located in the stream of items are determined based on electromagnetic radiation directly reflected at the surface of the items, diffusely reflected electromagnetic radiation from the items, and / or the height of the items. A threshold value may be used to determine the optical properties of the items. Figure 5 , the directly reflected electromagnetic radiation can be viewed as the brightness at the maximum in the y direction, the diffusely reflected electromagnetic radiation can be viewed as the line width around the maximum in the y direction, and the height can be viewed as the maximum in the y direction. Determining the height is helpful when calculating the trajectory of an item in an item flow.

[0053] Analysis of information from the optical scan may also include Figure 5 The dual surface shown in FIG is used to identify and analyze several surfaces of transparent objects located in an object flow.

[0054] According to one embodiment of the present invention, determining the transparency of an item in a stream of items is accomplished by comparing directly reflected electromagnetic radiation to threshold values. A first threshold is used to determine the presence of an item; if the directly reflected electromagnetic radiation exceeds the first threshold, the item is present. A second threshold, higher than the first threshold, is used to determine whether the item is transparent; if the directly reflected electromagnetic radiation does not exceed the second threshold, the item is transparent. Several such thresholds can be applied to determine the likelihood that an item is transparent. Combinations of thresholds for different parameters (i.e., directly reflected electromagnetic radiation at the item's surface, diffusely reflected electromagnetic radiation from the item, and / or the item's height) can be applied to determine multiple optical properties of the item.

[0055] Alternatively or in addition to threshold determination, lookup tables, deep learning, and / or support vector machines may be used to determine the performance of an item.

[0056] To remove ambient electromagnetic radiation when analyzing the detected electromagnetic radiation, it is possible to record frames with the laser on and frames without the laser. Background subtraction is then performed during the analysis to remove ambient electromagnetic radiation. For this purpose, a pulsed laser using a beam splitter can also be used.

[0057] The apparatus may further comprise a removal unit, such as an air blower, configured to remove those items that fail the analysis and thus sort the items based on the analysis.

[0058] The device may additionally comprise a bandpass filter located on the detector, polarized electromagnetic radiation or a polarization filter located in front of the detector.

[0059] The device can also use scanning 3D detection with a polygon mirror or can be used in combination with other detectors.

[0060] Figure 2 Shown with Figure 1 The apparatus is similar to the apparatus of FIG. 1 , but comprises a plurality of parallel line lasers 8 arranged to generate a plurality of parallel laser lines. In this case, this enables one or more cameras 14 to detect electromagnetic radiation reflected from a plurality of parallel laser lines located in a plurality of detection zones 12 at different locations in the free-fall path 6 of the stream of items 4. In this way, the position of items located in the different detection zones 12 can be determined, thereby determining the movement or trajectory of the items in the stream of items 4.

[0061] In sorting systems, item speed and direction of movement are often assumed to be constant during and between detection and ejection. If items move at a non-constant speed, there's a risk that rejected items may not be accurately removed. In some cases, the ejection window is increased to compensate for variations in movement. This results in more stable ejection, but also increases the removal of unwanted items from the item stream 4.

[0062] An alternative to all detection zones being located in the free-fall path of the article stream is that one or more of the detection zones are located in the article stream on the conveyor belt before the free-fall path.

[0063] The minimum distance between detection and ejection is determined by pixel size and latency. For systems with large pixel sizes, the minimum distance between detection and ejection can be quite large. If two detectors are combined, item movement degrades the convergence algorithm and, therefore, ejection performance. By determining the item's trajectory within the item flow, items can be ejected more accurately, resulting in better overall sorting.

[0064] Alternatively or complementary to using the classification data for sorting as described above, the data from the classification step can be used in the same device or transmitted to another device for use in various operations (such as classification) at a later stage and for statistical analysis.

[0065] Figure 6 Shown by Figure 2 The motion evaluation of the items is performed by a device. Two high-resolution detectors A and C are responsible for the motion evaluation of the items, while the low-resolution detector B is responsible for the material classification of the items. The items detected by the first high-resolution detector A are searched and mapped to the corresponding items in the second high-resolution detector C. The positions of the items located in the low-resolution detector B and the blow rod D are interpolated based on the corresponding positions of the items in the first and second high-resolution detectors A and C. The sensor data set of the low-resolution detector B is combined into the interpolated image position. The blow rod D uses the interpolated position for injection. The positions of the first and second high-resolution detectors A and C are disjoint, while the low-resolution detector B can be installed anywhere. For rolling items, the interpolated position reduces the error and convergence for injection.

[0066] The device may also include multiple lasers of different wavelengths that can be used to determine further optical properties such as the color of the item and other parameters based on the spectrum. Figure 2 ) can be used for this purpose, but also multiple pulsed lasers located at the same optical plane can be used for this purpose.

[0067] The device can also combine different laser polarizations to filter out the portion of reflected electromagnetic radiation and more easily differentiate the properties of items located in a stream of items. The device can, for example, comprise several lasers with different polarizations or a polarization camera.

[0068] Figure 3 Shown with Figure 1A similar device for inspecting items is provided. However, in this embodiment, the device includes a camera 14 that detects radiation in an area covering both the inspection area 12 and an area 22 that linearly illuminates a background element 24. This enables the camera 14 to detect reflections of the linear illumination on the background element 24, which enables the presence of an item in the inspection area 12 to be determined based on the reflections from the background element 24. This is helpful when inspecting items that exhibit very low levels of reflection. Here, a single camera 14 covers both the inspection area 12 and the area 22 located above the background element 24; however, two different detectors could also be used for the purposes of the present invention.

[0069] Figure 7 Shown by the Figure 3 Schematic diagram of electromagnetic radiation detected by a detector in a device. When an object that reflects electromagnetic radiation emitted by the laser line is present in the detection area, an object signal will be present. The background signal can be further used to determine the presence of very dark objects (i.e., those that do not reflect substantial electromagnetic radiation) in the detection area. The background signal (electromagnetic radiation emitted by the laser line and reflected by background elements) can also be used as a way to calibrate the laser line against dark areas for background reference.

[0070] Laser lines reflected by background elements can also be used to determine whether an item in the item stream is transparent, since a transparent item will transmit a portion of the emitted electromagnetic radiation, whereas an opaque item will not transmit the emitted electromagnetic radiation.

[0071] Figure 4 is a flow chart of a method for inspecting items, comprising the following steps: a guiding step S1 of guiding a continuous stream of items 4 into a free-fall path 6, feeding the stream of items 4 along the free-fall path through a detection area 12 in a single item layer; an irradiation step S2 of irradiating the detection area 12 in a first direction 10; an optical scanning step S3 of optically scanning the detection area 12 in a second direction 16; and an analyzing step S4 of analyzing information from the optical scanning; wherein a measuring plane does not intersect the first direction 10 and has a cross section in the detection area 12.

[0072] Possible applications of the method and apparatus include, but are not limited to, sorting and / or separation of glass, foil, napkins, printed circuit boards, cartridges, mining materials, and quality analysis of food products with regard to the sizing and detection of cracks or foreign material. It can also be used to identify polymers in waste streams.

[0073] Those skilled in the art will recognize that the present invention is not limited to the above-described embodiments. On the contrary, various modifications and variations are possible within the scope of the claims. For example, the radiation source and the detector can be arranged in any direction as long as the direction allows the method according to the present invention to be performed.

[0074] Moreover, variations of the disclosed embodiments may be understood and effected by those skilled in the art in practicing the claimed invention from a study of the drawings, the disclosure, and the claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality.

[0075] Itemized Enumeration of Exemplary Embodiments (IEE)

[0076] IEE1. A method for classifying items, the method comprising the following steps:

[0077] - a guiding step of guiding the continuous stream of articles from the transport mechanism directly into the unsupported path so that the stream of articles is fed along the unsupported path through the inspection area;

[0078] - an irradiation step, emitting electromagnetic radiation along a first direction to illuminate the detection area, the emitted electromagnetic radiation extending in a direction orthogonal to the first direction to form a radiation band;

[0079] - an optical scanning step of optically scanning said detection area to detect electromagnetic radiation reflected by at least one object located in said detection area by observing said detection area along a second direction,

[0080] wherein the first direction and the second direction have a cross section located in the detection area and form an angle in the range of 3°-80° relative to each other;

[0081] - an analysis step of analyzing the information from the optical scan; and

[0082] - a sorting step of sorting the objects from the flow of objects based on analysis of the reflection information from the optical scan;

[0083] Wherein the step of analyzing information from the optical scan includes analyzing the object based on intensity and dispersion of radiation detected from the optical scan.

[0084] IEE2. The method according to IEE1, wherein the sorting step of sorting the items further comprises sorting the items from the item stream in at least two different directions based on analysis of reflection information from the optical scan.

[0085] IEE3. A method according to any one of the aforementioned IEEs, wherein the analyzing step of analyzing information from the optical scan further includes determining reflection information by comparing electromagnetic radiation from illumination directly reflected by at least one item located in the item flow with a first threshold, and thereafter determining the transparency of the at least one item by comparing electromagnetic radiation from illumination directly reflected by the at least one item with a second threshold, wherein the second threshold is above the first threshold, and thereafter the reflection information is set.

[0086] IEE4. A method according to any one of the preceding IEEs, wherein the step of analyzing information from the optical scan further comprises determining height profiles of items located in the stream of items.

[0087] IEE5. A method according to any one of the preceding IEEs, wherein the step of analyzing information from the optical scan further comprises comparing the information with information in a lookup table and / or comparing the information with a threshold value.

[0088] IEE6. A method according to any of the preceding IEEs, wherein the step of analyzing information from the optical scan comprises the use of deep learning or the use of a support vector machine.

[0089] IEE7. The method according to any one of the aforementioned IEEs further includes a step of optically scanning an area on a background element where the line irradiation impacts the background element, wherein the step of analyzing information from the optical scan includes determining whether material is present in the detection area based on information from the optical scan of the area located on the background.

[0090] IEE8. The method according to IEE7, wherein the step of optically scanning the area located on the background element and the step of optically scanning the detection area are simultaneously performed using one camera.

[0091] IEE9. A method according to any one of the preceding IEEs, wherein the step of irradiating the detection area with electromagnetic radiation is performed with a plurality of line irradiations for a plurality of detection areas, and the step of optically scanning the detection area is performed with a plurality of measurement lines for the detection area.

[0092] IEE10. The method according to IEE9, wherein the step of analyzing information from the optical scan includes determining the movement of items located in the stream of items.

[0093] IEE11. A method according to IEE9 or 10, wherein the plurality of line illuminations have different wavelengths, wherein the analyzing step of analyzing information from the optical scan comprises determining optical and physical properties of items located in the stream of items.

[0094] IEE12. A method according to any one of IEEs 9 to 11, wherein the plurality of line illuminations have different polarizations.

[0095] IEE13. A device for sorting articles, the device comprising:

[0096] a transport mechanism arranged to transport the flow of articles such that, after leaving the transport mechanism, the flow of articles follows an unsupported path along which the flow of articles is fed through the detection area;

[0097] a radiation source configured to emit electromagnetic radiation in a first direction for irradiating the detection area. The radiation source is configured to generate a line illumination;

[0098] a detection unit arranged to observe said detection area in a second direction and to detect electromagnetic radiation reflected by at least one object located in the detection area,

[0099] wherein the first direction and the second direction have a cross section located in the detection area and form an angle in the range of 10°-80° relative to each other;

[0100] an analyzing unit operatively connected to the detection unit and arranged to determine the transparency information by comparing electromagnetic radiation from the illumination directly reflected by at least one article located in the article flow with a first threshold value for determining whether a material is present in the detection area, and thereafter comparing the electromagnetic radiation from the illumination directly reflected by the at least one article with a second threshold value for determining whether the material present is transparent, wherein the second threshold value is above the first threshold value, and thereafter setting the transparency information;

[0101] A removal unit configured to remove objects from the object flow (4), wherein the removal of the objects is based on an analysis in the analysis unit.

[0102] IEE14. The apparatus according to IEE13, wherein the detection unit is further configured to sense electromagnetic radiation reflected by a position on the background element at which the electromagnetic radiation from the radiation source strikes the background element.

[0103] IEE15. Apparatus according to IEE13, comprising a plurality of radiation sources configured to irradiate articles in the article stream at a plurality of positions along the unsupported path.

Claims

1. A device for sorting items, the device comprising: a transport mechanism (2) arranged to transport a flow of articles (4) such that the flow of articles (4) follows an unsupported path (6) after leaving the transport mechanism (2), the flow of articles being fed through a detection area (12) along the unsupported path; a radiation source (8) configured to emit electromagnetic radiation in a first direction (10) for irradiating the detection area (12), the radiation source being configured to produce a line irradiation; a detection unit (14) arranged to observe the detection area (12) along a second direction (16) and to detect electromagnetic radiation reflected by at least one object located in the detection area (12), wherein the first direction (10) and the second direction (16) have a cross section located in the detection area (12) and form an angle in the range of 3°-80° relative to each other; an analysis unit operatively connected to the detection unit (14) and arranged to determine transparency or reflection information by comparing electromagnetic radiation from illumination directly reflected by the at least one article located in the article stream with at least one threshold value or a look-up table to determine whether the material present in the detection area is transparent and thereafter setting the transparency and reflection information; and a removal unit, configured to remove objects from the object flow (4), wherein the removal of the objects is based on the analysis in the analysis unit, Wherein, the analysis unit is further arranged to determine transparency information in the following manner: determine whether there is material in the detection area by comparing electromagnetic radiation in illumination directly reflected by at least one item in the item flow with a first threshold or a lookup table, and thereafter determine whether the existing material is transparent by comparing electromagnetic radiation in illumination directly reflected by the at least one item with a second threshold or a second lookup table, wherein the second threshold is above the first threshold, and thereafter the transparency information is set.

2. The device according to claim 1, wherein The first direction (10) and the second direction (16) form an angle in the range of 10°-80° with respect to each other.

3. The device according to claim 1, wherein: The detection unit is further configured to sense electromagnetic radiation reflected by a location on the background element where electromagnetic radiation from the radiation source impinges on the background element.

4. The apparatus of claim 1, comprising a plurality of radiation sources configured to irradiate articles located in the stream of articles at a plurality of locations along the unsupported path.

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