Inspection arrangement and method for analysing items

Abstract

An method and inspection arrangement for detecting and analysing ia. EM- excitable items (102) present in an ispection zone (104), by irradiating the items with exciting optical radiation (151) and illuminating optical radiation (152), while substantially blocking (128) a range of the generated optical radiation from reaching the items to be inspected; where optical radiation within this blocked wavelength range (152,154) is used for calibrating the inspection system.

Description

[0001] INSPECTION ARRANGEMENT AND METHOD FOR ANALYSING ITEMS

[0002] Technical field

[0003] This disclosure relates to inspection of items, especially it relates to material detection and analysis of items in a flow by means of optical radiation.

[0004] Background

[0005] Throughout a wide range of industries identification, detection, classification and sorting of various objects or items are frequently required and desired.

[0006] In its simplest form, manual identification of objects by a person may be employed to advantage when a limited number of objects are to be identified, sorted and classified. The person in question may then, based on his / her knowledge identify and classify the objects concerned. This type of manual identification is however monotonous and prone to errors. Also, the experience level of the operator will significantly influence the results of the operation performed by the operator. Moreover, manual identification of the above kind suffers from low identification speeds.

[0007] In industry, identification, sorting and classification of bulk objects is therefore often performed by machines where the bulk objects are supplied in form of a continuous object stream. Such machines are generally faster than an operator and can operate for longer periods of time, hence offering an enhanced overall throughput. Machines of this kind are for instance used in agriculture for fruits and vegetables, and in recycling for identifying and sorting objects and materials that are to be recycled.

[0008] Machines of the above kind generally has some form of sensor that is used for identifying the objects of interest. For instance, an optical sensor in form of a spectral sensor may be employed to determine the quality of harvested fruits and vegetables. Similarly, a spectral sensor may be employed to determine the material of objects that are to be recycled.

[0009] In industrial systems for inspection, detection and analysis of items, there is always a demand for robustness and reliability. Summary of the invention

[0010] In view of the above, it is an object of the present intivetive concept to provide an improved inspection arrangement for detecting and analysing EM-excitable items in an inspection zone that is robust and reliable. Moreover, it is an object to provide an inspection arrangement and method capable of analysing and optionally sorting the same at high overall throughput. Further, it is an object of the inventive concept to provide a cost-effective inspection arrangement and method for inspection. In addition, it is an object of the invention to provide an inspection arrangement and method for inspection which arrangement and method enables modularity and facilitates scalability.

[0011] To achieve at least one of the above objects, and also other objects that will be evident from the following description, an inspection arrangement having the features defined in claim 1 is provided according to the present invention. Preferred variants of the inspection arrangement will be evident from the dependent claims.

[0012] According to a first aspect there is provided an inspection arrangement configured to detect and analyse EM-excitable items in an inspection zone, the inspection arrangement comprising:

[0013] • a transport arrangement configured to feed the EM-excitable items in a flow through the inspection zone,

[0014] • an irradiation arrangement configured to:

[0015] - provide optical radiation for irradiating the EM-excitable items, the provided optical radiation comprising: o a first wavelength range comprising exciting optical radiation selected to cause the EM-excitable items to emit fluorescent and / or phosphorescent radiation, and o a second wavelength range comprising illuminating optical radiation, which illuminating optical radiation is different from said exciting optical radiation and is selected to cause the EM-excitable items to provide an illumination response corresponding to itemspecific signatures of the EM-excitable items, wherein the illumination response is a portion of said illuminating optical radiation being reflected, transmitted, and / or scattered by said EM-excitable items, and

[0016] • a scanning element, • an optical arrangement configured to direct the exciting optical radiation and the illuminating optical radiation towards the scanning element,

[0017] • a detector arrangement having a field of view covering at least the inspection zone, the detector arrangement being configured to detect the emitted fluorescent and / or phosphorescent radiation and to detect the provided illumination response corresponding to item-specific signatures, and

[0018] • a processing unit configured to detect and analyse at least one of the EM-excitable items present in the inspection zone based on a combination of the fluorescent and / or phosphorescent radiation and the item-specific signature.

[0019] The scanning element is configured to redirect the exciting optical radiation and the illuminating optical radiation of the irradiation arrangement towards the inspection zone.

[0020] The irradiation arrangement or the optical arrangement comprises:

[0021] • a filter configured to transmit the illuminating optical radiation towards the scanning element and block a sub-range of the second wavelength range from directly reaching the scanning element, which sub-range of the second wavelength range is outside said illuminating optical radiation, and

[0022] • a calibration element adapted to be illuminated by all or a portion of the illuminating optical radiation, and to be illuminated by all or a portion of the sub-range of the second wavelength range of the irradiation arrangement, and adapted to redirect the illumination towards the detector arrangement, the calibration element being located within the field of view but outside the inspection zone of the detector arrangement, wherein the detector arrangement is further configured to detect said illumination redirected by the calibration element and to perform a calibration of said inspection arrangement based on at least said detected illumination reflected by said calibration element.

[0023] An inspection arrangement in accordance with the above is advantageous as it provides a compact and versitile calibration arrangement, suitable for a wide range of optical sensors such as spectrometers and cameras. The calibration arrangement is also useful for calibration of various combinations of different spectrometers and cameras and therefor allows one type of spectrometer in the inspection arrangement to be exchanged for another type of spectromenter, e.g. working in a different wavelength range, without the need to alter the calibration arrangement. According to a second aspect there is provided a method of detecting and analysing EM-excitable items in a flow through an inspection zone, the method comprising:

[0024] • transporting EM-excitable items in a flow through an inspection zone,

[0025] • by an irradiating arrangement, irradiating the EM-excitable items when present in the inspection zone with optical radiation, said optical radiation comprising:

[0026] - a first wavelength range comprising exciting optical radiation selected to cause the EM-excitable items to emit fluorescent and / or phosphorescent radiation, and

[0027] - a second wavelength range comprising illuminating optical radiation and calibration optical radiation, which illuminating optical radiation is different from said exciting optical radiation and is selected to cause the EM-excitable items to provide an illumination response corresponding to item-specific signatures of the EM-excitable items, wherein the illumination response is a portion of said illuminating optical radiation being reflected, transmitted and / or scattered by said EM-excitable items, wherein irradiating comprises:

[0028] - by a filter, filtering (504a) the second wavelength range, to transmit the illuminating optical radiation but block a sub-range,

[0029] - directing (504b) the exciting optical radiation and the illuminating optical radiation towards a scanning element, and directing () calibration optical radiation towards a calibration element arranged outside the inspection zone, the calibration optical radiation comprising at least a part of the second wavelength range,

[0030] - by said scanning element, redirecting the exciting optical radiation and the illuminating optical radiation towards the inspection zone,

[0031] - by said calibration element redirecting (504d) all or a portion of the calibration optical radiation towards a detector arrangement,

[0032] • by said detector arrangement having a field of view covering the inspection zone and the calibration element, detecting the emitted fluorescent and / or phosphorescent radiation, detecting said illumination response, and detecting calibration optical radiation redirected by the VIS calibration element.

[0033] The illuminating optical radiation is transmitted towards the scanning element while the calibration optical radiation is blocked from reaching the scanning element, which sub-range of the second wavelength range is outside the wavelength range of said illuminating optical radiation, and the calibration optical radiation comprises all or a portion of the illuminating optical radiation and all or a portion of the sub-range of the second wavelength range. The method further comprises:

[0034] • calibrating the inspection system’s settings based on the detected (516) calibration optical radiation, and

[0035] • analysing the EM-excitable items based on a combination of the fluorescent and / or phosphorescent radiation and the item-specific signatures.

[0036] Further details relating to the first and second aspects of the invention are presented below and in the dependent claims. It is pointed out that, details that are presented in relation to one of the aspects may also apply to the other aspect.

[0037] The inventive concept is based on the inventor’s realization that an improved inspection of EM excitable items may be achieved by irradiating the items with exciting optical radiation, also referred to as the first set of irradiation beams, and illuminating optical radiation, also referred to as the second set of irradiation beams, while substantially blocking a range of the generated optical radiation from reaching the items to be inspected, and still use the optical radiation within this blocked wavelength range for calibrating the inspection system. The expressions ‘exciting optical radiation’ and ‘first set of irradiation beams’ may be used interchangeably. Further, the expressions ‘illuminating optical radiation’ and ‘second set of irradiation beams’ may be used interchangeably.

[0038] This clever design of the inspection arrangement is advantageous as it provides a compact and versitile calibration arrangement, where the dual use of the illuminaton source provides a calibration of the sensors over a wavelenght range which is broader than the one used for the inspection.

[0039] Hence, there is provided a method and inspection arrangement for detecting and analysing i.a. EM-excitable items present in an ispection zone, by irradiating the items with exciting optical radiation and illuminating optical radiation, while substantially blocking a range of the generated optical radiation from reaching the items to be inspected; where optical radiation within this blocked wavelength range is used for calibrating the inspection system.

[0040] The filter may e.g. be a bandpass filter and or any other optical filter allowing a predetermined degree of transmission and blocking of predetermined wavelengthranges. The transmission and / or blocking may e.g. be at least 70 %, at least 80 %, at least 90 % or at least 95 % or at least 98 % of the incident radiaion at one or a plurality of said wavelength ranges of the first incident radiation.

[0041] In relation to this invention the terms “matter”, “EM-excitable items”, “non EM-excitable items” are to be understood as objects e.g. apples, rice grains, rocks, minerals and waste objects e.g. plastic waste including used containers. The matter may also comprise flakes of objects, such as parts or flakes of objects e.g. waste objects including used containers. The matter may also include labels or markers provided to said objects e.g. during or after the manufacturing of an object, or provided to a portion of said object if the object has been divided into at least two pieces. A steam of matter, or EM-excitable items provided in a flow, or a mix of EM- excitable items and non-EM-excitable items provided in a flow, comprises individual pieces of matter which pieces are to be inspected and preferably classified.

[0042] The footprint of said matter, i.e. the area occupied by each piece of said matter when arranged on a horizontal conveyor belt, may be within the range of 1-10 mm2 and / or 10-100 mm2 and / or 1-100 mm2 and / or 10-1000 mm2 and / or 1-100 cm2 and / or 40-400 cm2 and / or 10-1000 cm2 and / or 1-100 dm2. According to one example the individual pieces of said matter are separated from each other or only partly overlapping at least in a plane parallel with the direction of transportation (or the free fall).

[0043] In relation to this invention the term “classify” or “classification” is to be understood as based on at least a spectral response, also referred to as illumination response, of said matter, assign at least one class to said matter. This class is e.g. used by a sorting system when directing the piece of matter towards one of at least to available destinations, based on properties such as the colour, material, quality, label of the piece of matter and / or combinations of these properties. The class can be a number representing the value of this property such red, green, yellow; oil, plastic, glass, textile, wood, at least 90 % metal content; ripe, rotten, degraded; food container, non-food container. It can also be a sorting class: to be rejected, possibly to be rejected further inspection is required, possibly acceptable further inspection is required, acceptable. According to one example the inspection arrangement is configured to classify the pieces in said stream of matter based on their individual Phosphorous response or the characteristic of their Phosphorous response. In relation to this invention the term characteristic of the Phosphorous response is a property e g. duration, rise time, decay time and / or intensity for the emitted Phosphorous spectrum or a predetermined wavelength range of the emitted Phosphorous spectrum.

[0044] Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation. It is a form of luminescence. In most cases, the emitted light has a longer wavelength, and therefore a lower photon energy, than the absorbed radiation. A perceptible example of fluorescence occurs when the absorbed radiation is in the ultraviolet region of the spectrum (invisible to the human eye), while the emitted light is in the visible region. Fluorescent materials cease to glow nearly immediately when the radiation source stops, unlike phosphorescent materials, which continue to emit light for some time after.

[0045] Phosphorescence is a type of photoluminescence related to fluorescence. When exposed to light (radiation) of a shorter wavelength, a phosphorescent substance will glow, absorbing the light and reemitting it at a longer wavelength. Unlike fluorescence, a phosphorescent material does not immediately reemit the radiation it absorbs. Instead, a phosphorescent material absorbs some of the radiation energy and reemits it for a much longer time after the radiation source is removed.

[0046] There are two, separate mechanisms that may produce phosphorescence, called triplet phosphorescence and persistent phosphorescence. Persistent phosphorescence occurs when a high-energy photon is absorbed by an atom and its electron becomes trapped in a defect in the lattice of the crystalline or amorphous material. A defect such as a missing atom (vacancy defect) can trap an electron like a pitfall, storing that electron's energy until released by a random spike of thermal (vibrational) energy. Such a substance will then emit light of gradually decreasing intensity, ranging from a few seconds to up to several hours after the original excitation.

[0047] In the case of triplet phosphorescence, the electron which absorbed the photon (energy) undergoes an unusual intersystem crossing into an energy state of different (usually higher) spin multiplicity, usually a triplet state. As a result, the excited electron can become trapped in the triplet state with only "forbidden" transitions available to return to the lower energy singlet state. These transitions, although "forbidden", will still occur in quantum mechanics but are kinetically unfavoured and thus progress at significantly slower time scales. Most phosphorescent compounds are still relatively fast emitters, with triplet decay-times in the order of milliseconds.

[0048] The matter to be classified is provided as a stream of matter or in a flow through the inspection zone, and the apparatus irradiates the matter or EM-excitable items which are to be classified with optical radiation, e.g. within the UV wavelength range, designed to cause the irradiated matter to emit phosphorous and / or fluorescent radiation.

[0049] The EM-excitable items to be detected and analysed may be provided as a flow of matter, partly or only containing matter having a known characteristic of the Fluorescent and / or Phosphorous response. When the stream of matter only contains matter having a known characteristic, each one of the individual pieces of matter has a known characteristic of the Fluorescent and / or Phosphorous response, or a known characteristic of the Fluorescent and / or Phosphorous response which is above or below one or more given thresholds. When the stream of matter partly contains matter having a known characteristic of the Fluorescent and / or Phosphorous response, the stream may also comprise matter without any Phosphorous response or comprise matter having an unknown characteristic of the Fluorescent and / or Phosphorous response to the optical radiation by which it is to be irradiated.

[0050] According to one exemplifying embodiment the classifying of said EM-excitable items comprises determining a raise time and / or a decay time of one or both of the phosphorescence event and the fluorescent event.

[0051] By analysing the properties relating to one or both of phosphorescence event and the fluorescent event, the type of matter can be determined. The properties may e.g. be compared to one, two or all of a threshold, a look up table, and a reference. Data relating to e.g. said threshold, look up table and reference and other data, may be stored in a local or centralized database. According to one exemplifying embodiment, the classifying of said EM-excitable items further comprises comparing at least one property relating to the phosphoresce and / or fluorescence of said matter and / or to a respective one of the colour, the transmission, the scattering, and the reflectively of said matter, to data stored in a local or centralized database.

[0052] According to one exemplifying embodiment, the classifying said matter may comprises classifying said matter based on: at least one property relating to the phosphorescence and / or and the fluorescence event of said matter, and at least one property relating to a respective one of the color, the transmission and / or the reflectivity of said matter.

[0053] According to one exemplifying embodiment, the classifying comprises: determining by means of at least one of image processing and spectrum processing whether said matter is provided with a phosphorus marker; and / or identifying one or a plurality of materials making up said matter e.g. by means of spectrum processing; and / or upon determining a plurality of materials making up one piece of matter, determining if the combination of these materials is acceptable or non-acceptable.

[0054] A fluorescent and / or phosphorescent marker may e.g. be identified based on its shape, which profile may be identified by image processing. Additionally or alternatively, the phosphorus marker may e.g. be identified based on its spectrum or spectral signature emitted in response to being irradiated by said irradiation beam. A spectral signature may be identified by means of spectrum processing.

[0055] According to one exemplifying embodiment, the at least one irradiation beam causing the photoexcitation event comprises optical radiation within the ultraviolet and / or visible wavelength range. The least one irradiation beam may comprise optical radiation within one or a combination of the ultraviolet, visible, near infrared and infrared wavelength range. According to one exemplifying embodiment, optical radiation reflected, scattered and / or emitted by said EM excitable items in the first inspection zone may comprises optical radiation within one or a combination of the ultraviolet, visible, near infrared and infrared wavelength range.

[0056] It should be noted that within the context of this application, the optical radiation may be any type of optical radiation, visible or non-visible such as NIR, IR or UV, having an extension other than an infinite decimal beam or ray. In other words, the set of irradiation beams may mean any bundle or beam of optical radiation having a physical extension in space travers to its propagation direction, unless stated otherwise. The exciting optical radiation and / or the illuminating optical radiation may thus for instance form a beam of parallel light, a beam of non-parallel light, like a diverging or converging beam of light, or a band of light to give a few nonlimiting examples.

[0057] The irradiation unit may comprise a broadband spectral sources such as halogen illumination devices. Such halogen illumination devices may have a spectral distribution starting at about 400 nm and significantly decaying at about 2,5 pm. A maximum emission power may occur at about 1 ,3 pm. Additionally or alternatively, Xenon arc illumination devices may be used. A shorter wavelength such as from 200 nm and above may be achieved by using Xenon arc illumination devices. Additionally or alternatively, LED illumination devices or heating elements may be used. For UV- Fluorescence spectroscopy, LED illumination devices may be used to advantage. For mid infrared spectroscopy heating elements may be used to advantage. For high spatial and spectral resolution spectroscopy systems, Supercontinuum lasers may be used. For high spatial and spectral resolution multispectral systems, lasers at multiple wavelength may be used in combination. For highly spatial resolution optimized multispectral systems, LED’s and Pulsed LED’s may be used preferably in conjunction with line scan cameras.

[0058] According to at least one exemplifying embodiment the irradiation arrangement comprises one, two or a plurality of irradiation untis; when there are a two or plurality of irradiation untis, each unit may be arranged at a separate position relative the inspection zone independently of the other unit(s).

[0059] According to at least one exemplifying embodiment the detection arrangement comprises one, two or a plurality of detection untis; when there are a two or plurality of detection untis, each unit may be arranged at a separate position relative the inspection zone independently of the other unit(s).

[0060] The exciting optical radiation and the illuminating optical radiation will after being redirected by at least the scanning element reach the first inspection zone through which matter is provided. The matter including the EM-excitable items, is provided through the first inspection zone in the sense that the matter is transferred or conveyed through the first inspection zone. The matter is optionally provided also through a second inspection zone, arranged up-streams or down-streams of the first inspection zone. The matter may be provided through the first and / or second inspection zone in a continuous or intermittent manner. The matter may be provided through the first and / or second inspection zone sequentially or in parallel. Hence, a single piece of matter or a plurality of pieces of matter may be in the first inspection zone at the same time; and a a single piece of matter or a plurality of pieces of matter may be in the first inspection zone at the same time. Preferably a plurality of pieces of matter are present simultaneously in the respective inspection zone.

[0061] The first inspection zone and the second inspection zone may overlap, which is advantageous in that it may become easier to correlate matter in the first inspection zone to corresponding matter in the second inspection zone. In other words, it may become easier to determine when a particular piece of matter having passed through the first inspection zone passes through the second inspection zone. This setup is advantageous when the matter is traveling through the first inspection zone and / or second inspection zone in a random fashion, as is generally the case when the matter is free falling or sliding through the first inspection zone and / or second inspection zone.

[0062] The first inspection zone and the second inspection zone may overlap partially. The first inspection zone and the second inspection zone may overlap almost completely. Hence, the first inspection zone and the second inspection zone may be located partially at the same physical location.

[0063] The inspection arrangement may further comprise a focusing arrangement, wherein the focusing arrangement is adapted to direct and converge the first set of irradiation beams or the second set of irradiation beams on a scanning element, wherein the scanning element being adapted to redirect the first and second sets of irradiation beams towards the first inspection zone, whereby the first and second set of irradiation beams is focused in the vicinity of the first inspection zone. Matter provided through the first inspection zone may thus be efficiently irradiated by the first set of irradiation beams or the second set of irradiation beams converging at the first inspection zone. The scanning element may scan the first and second set of irradiation beams at the first inspection zone.

[0064] The scanning element may be one of a rotating polygon mirror and a tilting mirror.

[0065] According to at least one exemplifying embodiment, the irradiation arrangement comprises a first illumination device configured to emit the first wavelength range, a second illumination device configured to emit the second wavelength range, and a shield arranged between the first and second illumination devices and arranged to block generated optical radiation except the calibration radiation from illuminating the calibration element.

[0066] An advantage related to the presence of a shield is that a more accurate calibration may be achieved. The purpose of the calibration is e.g. to detect and correct shifts in alingment of the irradiation arrangement / irradiation unit and / or ageing of the illumination devices, and / or to calibrate the equipment for variations in ambient temperatur. Additonally or alternatively, the purpose may be to set up or prepare the inspection arrangement for the inspection session at hand.

[0067] According to at least one exemplifying embodiment the sheild is made of an opaque material such as metal, or the shield is configured to block at least 90%, or at least 95 %, or at least 98 %, or at least 99 % of the incident radiation at least within the wavelength of the illumination response or the illumination response of interest. When the illumination response covers a range of wavelengths, the processing unit may be configured to only analyse a sub-range of these wavelengths; this sub-range of wavelengths may be referred to as the illuminations response of interest.

[0068] According to at least one exemplifying embodiment, the scanning element is configured to redirect the fluorescent and / or phosphorescent radiation from the inspection zone, and also the reflected illumination responses from the inspection zone, towards the detector arrangement.

[0069] An advantage related to this embodiment is that a more accurate inspection and more compact inspection arrangement may be achieved.

[0070] According to at least one exemplifying embodiment, the scanning element comprises a polygon mirror configured to sweep the exciting optical radiation and the illuminating optical radiation of the irradiation arrangement over the inspection zone or over any item present in the inspection zone.

[0071] An advantage related to sweeping the optical radiation over the inspection zone by use of a polygon mirror, is that the substantially constant rotation speed of the polygon mirror provides a sweep without significant retardations and accelerations and thereby a simpler processing without the need to compensate for significant accelerations and retardations.

[0072] According to at least one exemplifying embodiment, the scanning element () comprises two polygon mirrors arranged adjacent to each other, of which one of the polygon mirrors is configured to sweep the exciting optical radiation over the inspection zone and a the other of the of the polygon mirrors is configured to sweep the illuminating optical radiation over the inspection zone, wherein the two polygon mirrors preferably have coinciding rotation axes.

[0073] According to one exemplifying embodiment, the first wavelength range comprises any combinations of wavelengths A1 within the range of 100 nm < A1 < 400 nm, and the second wavelength range comprises any combinations of wavelengths A2 within the range of 200 nm < A2 < 5000 nm, or any combinations of wavelengths within the range of 400 nm < A2 < 2000 nm; where A1 and A2 are preferably be selected such that all A1 < all A2. According to at least one embodiment A1 and A2 are generated by the same irradiation source. Alternatively, A1 and A2 are generated by different irradiation sources.

[0074] An advantage related to this embodiment is that it provides a useful balance between the wavelength ranges that may provide information about predetermined characteristics within the sensitivity ranges of costeffective sensors.

[0075] According to at least one embodiment, the detection arrangement comprises: an optical sensor arrangement configured to receive and analyze radiation reflected and / or scattered by items present in the inspection zone, and the detection arrangement is configured to determine item positions of said items and / or material information and / or item category of said items based on an analysis provided by the optical sensor arrangement.

[0076] According to one embodiment, the sensor arrangement comprises: a spatial detection system including at least one of: i) a laser triangulation arrangement configured to: illuminate, by means of laser emitting unit, at least a portion of the detection zone through which the items are provided; capture, by means of a light sensor, at least a part of laser light reflected by a surface of an item within said detection zone, and determine, based on an analysis of said captured laser light, at least spatial information of said item; ii) a time-of-flight detection arrangement configured to: emit, by means of a signal emitting unit, a signal to at least a portion of the detection zone through which the items are provided; capture, by means of a signal sensor, a reflected signal reflected from a surface of an item within said detection zone, and determine, based on a time between the emission of said signal and the capture of the reflected signal, at least spatial information of said item; iii) a stereo vision detection arrangement configured to: capture, by means of a first imaging sensor associated with a first vantage point, a first image of an item within said detection zone; capture, by means of a second imaging sensor associated with a second vantage point, a second image of said item within said detection zone, and determine, based on a comparison of the first image and the second image, at least spatial information of said item; iv) structured light detection arrangement configured to: project, by means of a structured light source, a light pattern to at least a portion of the detection zone through which the items are provided; capture, by means of an imaging sensor, an image of an item within said detection zone onto which at least a portion of the light pattern is projected, and determine, based on a distortion of said light pattern as a result of the geometry of said item, at least spatial information of said item; v) sequence-of-light-pattern detection arrangement configured to: project, by means of light source such as a structured light source, a sequence of light pattern to at least a portion of the detection zone through which the items are provided; capture, by means of an imaging sensor, a plurality of images of an item within said detection zone onto which at least a portion of the sequence of light patterns is projected, determine, based on said sequence of light patterns projected on said item, at least spatial information of said item.

[0077] According to one embodiment, said spatial information of said item includes: 3D information, and / or height information, and / or footprint area, and / or position, and / or shape, and / or volume, and / or weight, and / or density, and / or relative distances to nearby items to be sorted.

[0078] According to one embodiment, the sensor arrangement comprises: a spectroscopy system including a spectrometer, wherein the spectroscopy system is adapted to receive and analyse light reflected, emitted and / or scattered by items in the detection zone. The arrangement may be configured to determine item instance segmentation based on analysis provided by the spectroscopy system. The spectroscopy system may include near-infrared, NIR, spectroscopy system. NIR spectroscopy may advantageously enable detection of characteristics of surfaces of e.g. feed material. In the context of the application, NIR refers to nearinfrared region of the electromagnetic spectrum. As a non-limiting example, nearinfrared region of the electromagnetic spectrum is in the interval of 780 nm to 2500 nm. As an alternative, or in combination, such a spectroscopy system may be configured to use region of the electromagnetic spectrum outside NIR, such as the visible region of electromagnetic spectrum or medium infrared. The spectroscopy system may be configured to use both NIR spectroscopy and X-ray spectroscopy. The spectroscopy system may be a VIS / NIR spectroscopy system configured to detect e.g. wavelengths within the visible spectrum and within the near-infrared spectrum.

[0079] The spectroscopy system may be configured to analyse light in the wavelength interval 400 - 1000 nm, or in the interval 500 - 1000 nm; and / or in the interval 1000 - 1900 nm or light having a wavelength above 900 nm; and / or in the wavelength interval 1900 - 2500 nm, and / or in the wavelength interval 2700 - 5300 nm and / or in the wavelength interval 900 - 1700 nm. Optionally, the spectroscopy system may be configured to analyse light in the wavelength interval 700 - 1400 nm. The spectroscopy system may analyse visible light. The spectroscopy system may analyse UV and / or NIR light. The spectroscopy system may analyse IR light. Different types of spectroscopy system may be used depending on characteristics of the matter to be detected.

[0080] According to one embodiment, the arrangement further comprising: at least two sorting arrangements configured to sort items into a respective one or more receiving zones depending on item category, wherein at least two of said two sorting arrangements are configured to sort based on sensor data of said detector arrangement.

[0081] According to one embodiment, ejection sorting includes sorting items into at least a first item category, said first item category based on a first material property set and / or a second material property set. The irradiation arrangement may also comprise several lasers of different wavelength, which enables for determination of further optical properties such as the colour of the items and analysis of other parameters based on spectroscopy. Lasers at different positions can be used for this purpose, but also multiple pulsed lasers at the same optical plane is a possibility. The sensor arrangement may also combine different laser polarizations to filter portions of the reflected electromagnetic radiation and more easily distinguish properties of the items in the item stream. The sensor arrangement may for instance comprise several lasers with different polarizations or a polarization camera.

[0082] According to at least one exemplifying embodiment, the detector arrangement is configured to classify the EM-excitable items in at least two categories based on a combination of the detected florescent and / or phosphorescent radiation, and the detected item specific signature.

[0083] According to at least one exemplifying embodiment, the inspection arrangement further comprises a sorting arrangement configured sort out EM- excitable items classified in one of the at least two categories from the flow of EM- excitable items. After being sorted out the EM-excitable items are preferably transported or conveyed or urged to a dedicated container or collection point, optionally passing further sorting stations along the path towards the dedicated container or collection point.

[0084] According to at least one exemplifying embodiment, the EM-excitable items are containers and / or portions of containers, and wherein the detected florescent and / or phosphorescent radiation is indicative of a material compositions of the EM- excitable items, and the item specific signatures are indicative of residues, associated with the EM-excitable items, and preferably indictive of contents, e.g. oil, having been in contact with the EM-excitable items.

[0085] According to at least one exemplifying embodiment, the EM-excitable items comprises markers configured to emit the florescent and / or phosphorescent radiation, the markers preferably being implemented in form of at least one of: a paint, a print, a sticker, and / or a label.

[0086] According to one non-limiting example, the information content in the marker may denote food grade material, and / or the information content in the marker may denote non-food grade material.

[0087] According to at least one exemplifying embodiment, when the detector arrangement is configured to classify the EM-excitable items in at least two categories based on a combination of the detected florescent and / or phosphorescent radiation, one of said at least two categories corresponds to, or is confined to, food compliant items; and said sorting arrangement is preferably configured to sort out the EM-excitable items that are classified as food compliant items from the flow of EM-excitable items. The classification as food compliant item is preferably being based on the detected florescent and / or phosphorescent radiation indicating that a material composition of the EM-excitable is approved as food compliant, and / or that the detected item specific signature optionally indicating that the EM-excitable item (102) is not to be rejected. One example of the latter is when the EM-excitable item is determined to bee free from a toxic substances; i.e. an EM-excitable item containing toxic substances is to be refused or rejected; while an EM-excitable item not containing toxic substances is to be kept.

[0088] Additionally or alternatively, one of said at least two categories corresponds to, or is confined to, non-food compliant items, and said sorting arrangement is configured to sort out the EM-excitable items that are classified as non-food compliant items from the flow of EM-excitable items, wherein the classification as non-food compliant item is optionally based on the detected florescent and / or phosphorescent radiation indicating that a material composition of the EM-excitable is approved as food compliant, and / or that the detected item specific signature optionally indicating that the EM-excitable item is non-food compliant, e.g. due to traces of motor oil.

[0089] According to at least one exemplifying embodiment, one of said at least two categories corresponds to, or confined to, reusable textiles, and wherein said sorting arrangement is configured to sort out the EM-excitable items that are classified as reusable textiles from the flow of EM-excitable items, wherein the classification as a reuseable textile is optionally based on the detected florescent and / or phosphorescent radiation indicating that a material composition of the EM-excitable is approved as a reuseable textile, and / or that the detected item specific signature optionally indicates that the EM-excitable item is not to be refused. A texile may be refused e.g. due the the textile composition and / or due to the textile being soiled by oil or body fluids.

[0090] According to at least one exemplifying embodiment, the the item specific signature relates to at least one of reflectivity, size and geometric form, wherein said reflectivity comprises one or a combination of wavelength dependent intensity variations, spatial distribution of the reflected radiation, polarization of the reflected radiation. The wavelength dependent intensity variation may e.g. be caused by the colour of material, and the polarization of the reflected radiation may e.g. be caused by the structure of the material surface. According to at least one exemplifying embodiment, the transporting arrangement is configured to feed EM-excitable items and non-EM excitable items in a flow through the inspection zone, wherein said illuminating optical radiation is preferably selected to cause the non-EM-excitable items to provide an illumination response corresponding to itemspecific signatures of the non-EM-excitable items, wherein the illumination response is a portion of said illuminating optical radiation being reflected, transmitted, and / or scattered by said non-EM-excitable items, wherein detector arrangement is optionally configured to detect the itemspecific signature of the non-EM excitable items based on the item specific signature, wherein the processing unit is optionally configured to detect and analyse at least one of the non-EM-excitable items present in the inspection zone based on the item specific signature.

[0091] Optionally, the inspection arrangement is configured to classify non-EM- excitable items in at least one category based on the item specific signature. According to at least one exemplifying embodiment, the sorting arrangement is configured to sort out non-EM-excitable items classified in one of the at least one category from the flow of EM-excitable items. After being sorted out the non-EM- excitable items are preferably transported or conveyed or urged to a dedicated container or collection point, optionally passing further sorting stations along the path towards the dedicated container or collection point.

[0092] The inspection arragement, and optionally said irradiation arrangement, may include a further irradiation arrangement or illumination device, which further illumination device is adapted to emit a further set of irradiation beams. By this arrangement, a more intense illumination may be provided at the first inspection zone. Further, the illumination of the first inspection zone may easily be tailored by using different types of illumination devices having different characteristics as the first, second and further illumination devices. Furthermore, a more robust inspection arrangement may be achieved. The inspection arrangement may not need to be taken out of operation if one of the first and second illumination devices fails and may consequently still be operated during exchange of one of the illumination devices.

[0093] The optical arrangement may include a focusing arrangement comprising a first focusing element adapted to direct and converge the first and second set of irradiation beams towards the scanning element and a further focusing element adapted to direct and converge the further set of irradiation beams towards the scanning element, which is advantageous in that the first and further sets of irradiation beams may be directed and converged individually towards the scanning element. The focusing elements may be any optical element capable of focusing and directing the first and / or further sets of irradiation beams. The focusing elements may be a combination of a plurality of optical elements acting jointly. The focusing elements may direct the first, second and / or further sets of irradiation beams along a direction of incoming optical radiation of the first, second and / or further sets of irradiation beams. The first focusing element may be a lens or a mirror. The first focusing element may be a combination of a lens and a mirror. The further focusing element may be a lens or a mirror. The second focusing element may be a combination of a lens and a mirror.

[0094] The irradiation arrangement or irradiation arrangement may include a single irradiation device adapted to emit the first set of irradiation beams and the further set of irradiation beams, which is advantageous in that the irradiation arrangement may be made more energy efficient. Further, the irradiation arrangement may be made more compact since space may only have to be allocated to a single irradiation device.

[0095] The first and / or further focusing element may be a lens or a mirror. The first and / or further focusing element may be a full parabolic mirror or one or more partial parabolic mirrors. The first and / or further focusing element may be a full elliptical mirror or one or more partial parabolic mirrors; or a mirror with a shape optimized to focus optical radiation into the first inspection zone. The first and / or further focusing element may be an off-axis full or partial parabolic mirror. The first and / or further focusing element may be a combination of a lens and a mirror. The first and / or further focusing element may be a combination of a lens and a flat mirror.

[0096] The detector arrangement may comprise a spectroscopy system, which may include a first spectrometer system adapted to analyse optical radiation of a first wavelength interval and an optional second spectrometer system adapted to analyse optical radiation of a second wavelength interval, which is advantageous in that spectrometer systems adapted for analysis of a certain wavelength interval may be used. By this arrangement, more sensitive and accurate analysis may be performed. The first wavelength interval and the second wavelength interval may overlap or partially overlap. The first wavelength interval and the second wavelength interval may be separate intervals.

[0097] The spectroscopy system may include a first spectrometer system adapted to analyse optical radiation of a first wavelength interval, a second spectrometer system adapted to analyse optical radiation of a second wavelength interval and a third spectrometer system adapted to analyse optical radiation of a third wavelength interval. The spectroscopy system may include one or a plurality of spectrometer systems, each spectrometer system adapted to analyse optical radiation of one or a plurality of wavelength intervals.

[0098] The spectroscopy system may be a scanning spectroscopy system, which is advantageous in that accurate analysis ranging over a wavelength interval may be performed on the matter in the first inspection zone. Also, an image of the matter in the first inspection zone may be acquired, where the image including information form the analysis of the optical radiation received by the scanning spectroscopy system.

[0099] The inspection arrangement may further comprise a processing unit coupled to the detector arrangement, such as the spectroscopy system and / or the camerabased sensor arrangement, wherein the processing unit may be configured to determine a first property set pertaining to matter or EM excitable items in the first inspection zone based on an outputted signal of the spectroscopy system, and wherein the processing unit may be configured to determine a second property set pertaining to matter or EM excitable items in the first or second inspection zone based on an outputted signal of the camera-based sensor arrangement, dependent on which system that is present. The provision of a processing unit coupled to the spectroscopy system and / or the camera-based sensor arrangement brings about that the processing unit may determine properties or a property of matter or EM-excitable items in the respective first and / or second inspection zones. The processing unit may thus receive signals form the spectroscopy system and the camera-based sensor arrangement respectively. The received signals may be based on an analysis and / or processing of the optical radiation received by the spectroscopy system and / or the camera-based sensor arrangement respectively.

[0100] The inspection arrangement may be arranged to processes the received fluorescent and / or phosphorescent radiation in accordance with the method described in WO2023104832, which is hereby incorporated by reference in its entirety.

[0101] Is should be noted that within the context of this application, the term processing unit may be any unit, system or device capable of receiving a signal or signals or data from other entities and to process the received signals or data. The processing may for instance include calculating properties or a property based on the received the received signals or data, forwarding of the received signals or data and altering the received signals or data. The processing unit may be a single unit or may be distributed over a plurality of devices, such as a plurality of PCs, each having processing capabilities. The processing unit may be implemented in hardware or in software.

[0102] Is should be noted that within the context of this application, the term property set may be any set of data including any type of data. The property set may include any number of properties including 0. Hence, the property set may be an empty set, which for instance may be indicative of a non-presence of matter or non-presence of EM excitable items.

[0103] The first property set may be indicative of at least one of a spectral response of the matter, a material type of the matter, a colour of the matter, a fluorescence of the matter, a ripeness of the matter, a dry matter content of the matter, a water content of the matter, a fat content of the matter, an oil content of the matter, a calorific value of the matter, a presence of bones or fishbones of the matter, a presence of pest, a mineral type of the matter, an ore type of the matter, a defect level of the matter, a detection of hazardous biological materials of the matter, a presence of matter, a non-presence of matter, a detection of multilayer materials of the matter, a detection of fluorescent markers of the matter, a detection of phosphorescent markers of the matter, a quality grade of the matter, a physical structure of the surface of the matter and a molecular structure of the matter.

[0104] An example of a relevant hazardous biological material that may be detected is mycotoxin.

[0105] The above features of the first property set may be determined in specific combinations which may be useful for detecting matter in the first inspection zone. Examples of applications where such combinations are useful are sorting of pet food, detection of fishbones in fillets, paper sorting using visible and NIR spectroscopy, removal of foreign material and shells from pistachios, recycling of polymers to give a few non-limiting examples.

[0106] The second property set may be indicative of at least one of a height of the matter, a height profile of the matter, a 3D map of the matter, an intensity profile of reflected, emitted and / or scattered optical radiation, a volume centre of the matter, an estimated mass centre of the matter, an estimated weight of the matter, an estimated material of the matter a presence of matter, a non-presence of matter, a detection of isotropic and anisotropic optical radiation scattering of the matter, a structure and quality of wood, a surface roughness and texture of the matter and an indication of presence of fluids in the matter.

[0107] Examples of a relevant fluids are oil and water in food products.

[0108] The above features of the second property set may be determined in specific combinations which may be useful for detecting matter or EM-excitable items in the second inspection zone. Examples of applications where such combinations are useful are glass sorting and quartz sorting to give a few non-limiting examples.

[0109] The processing unit may be further configured to receive an input indicative of a viewing angle of the camera-based sensor arrangement with respect to the first or second inspection zone, and to compensate for the viewing angle of the camerabased sensor arrangement when determining the second property set, which is advantageous in that a more accurate subsequent sorting or ejection of the matter may be achieved. In practice the height of the matter in the first or the second inspection zone may be compensated for when determining a position of the matter in the first or the second inspection zone. By this, a subsequent sorting or ejection operation may affect or influence the matter in a location counteracting wrongful sorting or ejection. For instance, a sorter or ejector may impinge on matter at its estimated mass center thereby reducing the risk of for instance slipping or tumbling of the matter. An ejector may be configured with valve image processing steps for reducing or minimizing the compressed air consumption and energy consumption while keeping optimal sorting yield and sorting loss.

[0110] The processing unit may be configured to receive an input indicative of a geometry of the laser arrangement and the camera-based sensor arrangement with respect to the first or the second inspection zone.

[0111] The processing unit may be configured to compensate for the geometry of the laser arrangement and the camera-based sensor arrangement with respect to the first or the second inspection zone when determining the second property set.

[0112] The inspection arrangement may further comprise a sorting arrangement preferably coupled to the processing unit, wherein the sorting arrangement is adapted to eject matter into a plurality of fractions in response to receiving a signal form the processing unit based on the determined first property set and / or the determined second property set, the sorting arrangement being adapted to eject and sort said matter by means of at least one of a jet of compressed air, a jet of pressurized water, a mechanical finger, a bar of jets of compressed air, a bar of jets of pressurized water, a bar of mechanical fingers, a robotic arm and a mechanical diverter.

[0113] By the provision of an sorting arrangement coupled to the processing unit, the inspection arrangement may eject the matter into a plurality of fractions based on the determined first property set and / or the determined second property set. Hence, the matter may be sorted based on analysis performed by the spectroscopy system and / or the laser triangulation system. The plurality of fractions may be based on any of the determined properties. The fractions may for instance be based on material or colour. One faction may correspond to matter that is to be discarded or scrapped.

[0114] The ejection and sorting may be executed by a jet of compressed air, a jet of pressurized water, a mechanical finger, a bar of jets of compressed air, a bar of jets of pressurized water, a bar of mechanical fingers, a robotic arm or a mechanical diverter.

[0115] Alternatively, to being ejected and sorted the matter may be analyzed online by for instance a cloud service. The so analyzed matter may then be classified for instance in terms of purity, defect level, average color etc.

[0116] The transport arrangement may further comprise, a conveyor for conveying matter through the first inspection zone and the second inspection zone, or a chute, optionally including a vibration feeder, for sliding or freefal I ing of the matter through the first inspection zone and / or the second inspection zone.

[0117] By the provision of a conveyor, the matter may be conveyed through the first inspection zone and second inspection zone in a controlled manner. Matter conveyed through and analysed in the first inspection zone may then be conveyed through and analysed in the second inspection zone. By a controlled conveyance of matter through the first inspection zone and the second inspection zone matter may be kept track of. Hence, matter in the first inspection zone may be correlated or identified as being the same matter in the second inspection zone.

[0118] By the provision of a chute, optionally including a vibration feeder, the matter may be slid or made freefal ling through the first inspection zone and / or the second inspection zone. The matter may be slid though the first inspection zone and the second inspection zone. The matter may be made to freefall through the first inspection zone and the second inspection zone. The matter may be slid though the first inspection zone and made to freefall through the second inspection zone. The provision of a chute, optionally including a vibration feeder, is advantageous for small bulk object such as grains of different kinds.

[0119] According to a third aspect of the disclosure, a computer program is provided. The computer program comprises instructions which, when the program is executed by a computer, cause the computer to carry out the method according to the second aspect or any embodiments thereof.

[0120] According to a fourth aspect of the disclosure, a computer-readable storage medium is provided. The computer-readable storage medium comprises instructions which, when executed by a computer, cause the computer to carry out the method according to the first aspect or any embodiments thereof.

[0121] Effects and features of the second and third and fourth aspects are largely analogous to those described above in connection with the first aspect. Embodiments mentioned in relation to the first aspect are largely compatible with the second and third and fourth aspects. Hence, all advantages detailed in disclosure pertaining to the first aspect or any embodiments thereof applies to the second and third and fourth aspect or any embodiments thereof. It is further noted that the disclosures relate to all possible combinations of features unless explicitly stated otherwise.

[0122] A further scope of applicability of the present invention will become apparent from the detailed description given below. However, it should be understood that the detailed description and specific examples, while indicating preferred variants of the present inventive concept, are given by way of illustration only, since various changes and modifications within the scope of the inventive concept will become apparent to those skilled in the art from this detailed description.

[0123] The invention is defined by the appended independent claims, with embodiments being set forth in the appended dependent claims, in the description and in the drawings. It is to be understood that this inventive concept is not limited to the particular component parts of the device described as such device may vary. It is also to be understood that the terminology used herein is for purpose of describing particular variants only, and is not intended to be limiting. Something that has been described as part of a whole, may also be used on its own. It must be noted that, as used in the specification and the appended claim, the articles "a," "an," "the," and "said" are intended to mean that there are one or more of the elements unless the context clearly dictates otherwise. Thus, for example, reference to "a unit" or "the unit" may include several devices, and the like. Furthermore, the words "comprising", “including”, “containing” and similar wordings does not exclude other elements or steps.

[0124] Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to “a / an / the [element, device, component, means, step, etc.]” are to be interpreted openly as referring to at least one instance of said element, device, component, means, step, etc., unless explicitly stated otherwise. Brief description of the drawings

[0125] The above, as well as additional objects, features, and advantages of the present inventive concept, will be better understood through the following illustrative and non-limiting detailed description, with reference to the appended drawings. In the drawings like reference numerals will be used for like elements unless stated otherwise.

[0126] Fig. 1 shows a schematic view of an inspection arrangement, according to an exemplifying embodiment.

[0127] Fig. 2 shows a schematic diagram of wavelength ranges for illumination and detection, according to an inventive concept.

[0128] Fig. 3 shows a schematic detail view of an inspection arrangement, according to an exemplifying embodiment.

[0129] Fig. 4 shows a schematic detail view of an inspection arrangement, according to an exemplifying embodiment.

[0130] Fig. 5 shows a schematic detail view of an inspection arrangement, according to an exemplifying embodiment.

[0131] Fig. 6 shows a schematic detail view of an inspection arrangement, according to an exemplifying embodiment.

[0132] Fig 7a, 7b show a spectral intensity graph of the optical radiation provided by an exemplifying illumination device

[0133] Fig 8 shows a schematic detail view of an inspection arrangement, according to an exemplifying embodiment

[0134] Fig. 9 shows a schematic flow chart of a method for detecting and inspecting items, according to an exemplifying embodiment.

[0135] All figures are schematic, not necessarily to scale, and generally only show parts which are necessary in order to elucidate the disclosure, wherein other parts may be omitted or merely suggested. Throughout the figures, the same reference signs designate the same, or essentially the same features.

[0136] Detailed description In the following description, the inventive concept is described with reference to an inspections arrangement configured to detect and analyse EM-excitable items present in an inspection zone. The present inventive concept is also described with reference to a method of detecting and analysing EM-excitable items present in an inspection zone. It should be noted that this by no means limits the scope of the invention, which is also applicable in other circumstances for instance with other types or variants of devices than the embodiments shown in the appended drawings. Further, that specific components are mentioned in relation to an embodiment of the inventive concept does not mean that those components cannot be used to an advantage together with other embodiments of the inventive concept.

[0137] Features illustrated in the attached drawings or described in the following as part of one embodiment may be used with another embodiment to yield still a further embodiment. In the interest of clarity, not all features of an actual implementation are described in this specification. Various structures, systems and devices are schematically depicted in the drawings for purposes of explanation only and so as to not obscure the description with details that are well known to those skilled in the art. Nevertheless, the attached drawings are included to describe and explain illustrative examples of the disclosed subject matter.

[0138] The inspection arrangement is suitable for sorting a wide range of EM- excitable items, such as fish containing fish bones, minerals, containers of fluorescent material where e.g. the whole or a portion of the container body is fluorescent.

[0139] Items to be sorted, e.g. for recycling purposes may have varying or complex material compositions, which makes them more or less suitable to be recycled. For instance, food beverage containers may have been filled with harmful contents that make them unsuitable to be refilled with food or even unsuitable for material recycling.

[0140] Even if the items may be marked with markers like bar-codes, QR-codes (Quick Response), labels or paints to be detected for identifying items suitable for recycling, the users may have used the items for other purposes. For instance, a person may have used a PET-bottle (PolyEthylene Terephthalate) for storing 1 chemicals which makes the normally food compliant container unsuitable or even dangerous for recycling.

[0141] In addition items may further originate from sources, e.g. not well-known providers, for which a recycler company has limited control. For instance, manufacturers that produces material combinations that comprises unsuitable or dangerous contents. Such unsuitable contents may then be identified by its itemspecific signature.

[0142] The items to be detected and inspected by this arrangement may be marked by a paint that excites fluorescent and / or phosphorescent radiation when being exposed to optical radiation of a first wavelength range. When the items also are illuminated by optical radiation of a second wavelength range, e.g. NIR, they provide an illumination response corresponding to item-specific signatures. By analysing items in an inspection zone based on a combination of excited fluorescence and / or phosphorescence and the illumination response, characteristics of the items may be detected. As will be further explained in connection with some exemplifying embodiments, approved items may be sorted to be collected, and items not approved may be sorted to be discarded.

[0143] Within this disclosure the term “EM-excitable items” (ElectroMagnetic- excitable) is used to denote any item to be sorted that is provided with a marker that emit exciting optical radiation, e.g. fluorescent and / or phosphorescent, when being exposed to optical radiation within a specific wavelength range. The EM-excitable items may be a bottle, a can, a box, etc., or a part of any such container that is passing an inspection zone for being sorted.

[0144] Fig. 1 schematically illustrates an inspection arrangement 100 for detecting and analysing items 102 that is provided through an inspection zone 104.

[0145] In the depicted inspection arrangement 100 of Fig. 1 , EM-excitable items (ElectroMagnetic) 102 are conveyed through the inspection zone 104 by means of a conveyor 108. However, the EM-excitable items 102 may be provided through the inspection zone 104 by any suitable means or manually without any technical means. Further, the EM-excitable items 102 may be provided through the inspection zone 104 by sliding or freefalling. Hence, the conveyor of Fig. 1 is optional. The depicted inspection arrangement 100 of Fig. 1 further includes a housing 110 arranged above the inspection zone 104. In other words, the housing 110 is arranged above the conveyor 108.

[0146] Now also referring to Fig. 3 which schematically discloses a selection of components arranged in the housing 110.

[0147] In the interior of the housing 110 there is provided an irradiation arrangement 114 adapted to emit a first set of irradiation beams 116 and a second set of irradiation beams 118 towards the first inspection zone 104.

[0148] In the interior of the housing 110 there is provided a spectroscopy system 120 adapted to receive and analyse optical radiation 122 which is reflected, emitted and / or scattered by EM-excitable items 102 in the first inspection zone 104.

[0149] The depicted apparatus 100 of Fig. 1 further includes a sorting arrangement 112 provided downstream of the first inspection zone 104. The sorting arrangement 112 is adapted to eject and sort the EM-excitable items 102 being transported through the inspection zone 104. In this embodiment the sorting arrangement 112 is configured to eject approved EM-excitable items 102. However, the inventive concept is not limited thereto, alternatively, the sorting arrangement 112 may be configured to eject non-approved EM-excitable items 102. Within the inventive concept, the sorting arrangement 112 may also be configured to sort and eject the EM-excitable items 102 into a plurality of fractions. However, the sorting arrangement 112 of Fig. 1 is optional, as according to one embodiment the arrangement 100 only output statistics describing the characteristics of all or a portion of the items passing through the detection zone, i.e. without sorting these items.

[0150] The depicted inspection arrangement 100 of Fig. 1 further includes a control cabinet 111 arranged above the conveyor 108. The control cabinet 111 includes equipment used for controlling the apparatus 100. The equipment typically includes a processing unit 113 or control unit for controlling the conveyor 108, the sorting arrangement 112 and the equipment in the housing 110. The processing unit 113 is typically used to determine properties or a property of the EM-excitable items 102 based on measurement carried out by the equipment in the housing 110. Even in the processing unit 113 is illustrated as a separate unit in the figure, it is not limited thereto. It may be located at any suitable position where appropriate, e.g. in the housing 110. Fig. 2 shows a schematic diagram of wavelength ranges for illumination and detection according to an example. Optical radiation provided by the irradiation unit 114 is symbolized by arrows pointing downward 221 ,222 in the orientation of the drawing sheet. Fluorescent and / or phosphorescent radiation emitted by the EM- excitable items 102, as well as illumination response provided by the EM-excitable items 102, is symbolized by arrows pointing upward 231 ,232 in the orientation of the drawing sheet according to this example.

[0151] The location of the respective arrows in relation to the wavelength axis 201 schematically indicates the wavelength range of the optical radiation associated with the respective arrow.

[0152] The diagram is divided into sections according to wavelength ranges, where section 251 is within the UV wavelength range, section 252 is within the VIS wavelength range, and section 253 is within the NIR wavelength range. In the example of Fig. 2, the optical radiation provided by the irradiation arrangement comprises a first wavelength range comprising exciting optical radiation selected to cause the EM-excitable items 102 to emit fluorescent and / or phosphorescent radiation. The exciting optical radiation is symbolized by the arrow 221 . In this example the exciting optical radiation is within the UV wavelength range. The optical radiation further comprises a second wavelength range comprising illuminating optical radiation symbolized by arrow 222. Here, the illuminating optical radiation is within the NIR wavelength range.

[0153] The fluorescent and / or phosphorescent response, symbolized by arrow 231 , is in this example within the VIS wavelength range. The fluorescent and / or phosphorescent response may however be at least partly outside of the VIS wavelength range. The fluorescent and / or phosphorescent response 231 occurs in response to the EM-excitable item 102 being irradiated by the exciting optical radiation 221. The optical response, i.e., a portion of the illuminating optical radiation 222 being reflected, transmitted, and / or scattered by the EM-excitable item, is symbolized by arrow 232. The optical response 232 is in the NIR wavelength range.

[0154] In general, the exciting optical radiation 221 and the illuminating optical radiation 222 may be scaled and / or translated along the x-axis 201 of Fig 1 so as to cover other wavelength ranges. However, there is preferably always a separation between the exciting optical radiation 221 and the illuminating optical radiation 222, which separation preferably corresponds to at least a portion of the fluorescent and / or phosphorescent response 231 . The separation between the exciting optical radiation 221 and the illuminating optical radiation 222 may be achieved by a suitable filter described in relation to Fig. 4.

[0155] According to one example: all wavelengths of the exciting optical radiation 221 < all wavelengths of the fluorescent and / or phosphorescent response 231 < all wavelengths of the illuminating optical radiation 222; and all wavelengths of the fluorescent and / or phosphorescent response 231 < all wavelengths of the optical response 232. However, as the wavelength ranges may have some small, easily disregarded, disturbances: all significant wavelengths of the exciting optical radiation 221 < all significant wavelengths of the fluorescent and / or phosphorescent response 231 < all significant wavelengths of the illuminating optical radiation 222; and all significant wavelengths of the fluorescent and / or phosphorescent response 231 < all significant wavelengths of the optical response 232. A significant wavelength being a wavelength having a significant intensity above the noise level. For the fluorescent and / or phosphorescent response 231 and the optical response 232 a significant wavelength may refer to a wavelength within the wavelength range which is analysed by the processing unit.

[0156] As will be further described below, the irradiation unit 114 comprises a filter 128 configured to block a sub-range of the second wavelength range, which subrange is outside of the illuminating optical radiation. In the example of Fig. 2, the filter blocks optical radiation within the VIS wavelength range. Accordingly, no optical radiation is provided by the irradiation unit 114 within the VIS wavelength range for irradiating the EM-excitable items in the inspection zone 104.

[0157] Fig. 3 schematically shows components of the inspection arrangement 100 which are arranged within the housing 110 (see Fig. 1 ). As mentioned above, within the housing 110 there is provided an irradiation arrangement 114 and a spectroscopy system 120. The spectroscopy system may also be referred to as a detector unit 120.

[0158] The EM-excitable item 102 is conveyed through the inspection zone 104 in a direction generally perpendicular to the plane of the drawing sheet.

[0159] In the 2D schematic representation of Fig. 3, the first set of irradiation beams 116 and the second set of irradiation beams 118 are represented by the same dot- dashed arrow. The first set of irradiation beams 116 and the second set of irradiation beams 118 are directed towards the scanning element 140 by an optical arrangement. The scanning element 140 further redirects the irradiation beams 116, 118 towards the inspection zone.

[0160] The first set of irradiation beams 116 may be referred to as exciting optical radiation and the second set of irradiation beams 118 may be referred to as illuminating optical radiation.

[0161] Different configurations of the irradiation arrangement 114 and optical arrangement are shown in more detail in Figs. 4-6.

[0162] In this example, the scanning element 140 is in the form of a polygon mirror rotatable about a rotation axis R. Upon rotation of the polygon mirror 140, the first 116 and second 118 sets of irradiation beams are repeatedly scanned across the inspection zone 104. In more detail, by rotating the polygon mirror 140, the irradiation beams 116, 118 are redirected to scan the inspection zone 104 from a first end 104a of the inspection zone 104 to a second end 104b of the inspection zone 104 once per surface 140a, 140b and revolution of the polygon mirror 140. Fig. 3 illustrates how an EM-excitable item 102 present in the inspection zone 104 is irradiated by the irradiation beams 116, 118.

[0163] Optical radiation 122 emitted, reflected, transmitted, and / or scattered by the EM-excitable item 102 is reflected and directed by the polygon mirror 140 towards a folding mirror 170, which in turn reflects and directs the optical radiation 122 towards the spectroscopy system 120.

[0164] In the example of Fig. 3, the spectrometer system 120 comprises two sensors, e.g., a first sensor 131 and a second sensor 132. The spectrometer system 120 may comprise a plurality of sensors. Each sensor may be an array or matrix sensor, comprising a plurality of pixels. Each sensor is preferably associated with a respective diffractive element such as a grating. Each sensor and associated diffractive element is arranged at a different location within the spectroscopy system 120 and arranged to receive a respective portion of the optical radiation 122. In Fig. 3, a first grating 128 is associated with the first sensor 131 and a second grating 129 is associated with the second sensor. The optical is split in two different portions by means of a beam splitting element 123, for example a dichroic beam splitter 123, such that a respective portion of the optical radiation 122 is directed to each one of the first diffractive element 128 and second diffractive element 129.

[0165] Thus, the first sensor 131 may be configured to detect radiation within a first wavelength range, and the second sensor 132 may be configured to detect radiation within a second wavelength range. For example, the first sensor 131 may be configured to detect the emitted fluorescent and / or phosphorescent radiation, and the second sensor 132 may be configured to detect the illumination response, or vice versa. For example, the first sensor may be configured to detect VIS radiation, and the second sensor may be configured to detect NIR radiation. The spectroscopy system 120 may comprise more than two sensors. Each sensor may be configured to detect radiation within different wavelength ranges, or different sensors may be configured to detect radiation within partially or completely overlapping wavelength ranges.

[0166] The irradiation unit 114 is configured to direct calibration radiation towards a calibration element 144. The calibration radiation is reflected by the calibration element 144 and received by the polygon mirror 140, which redirects the calibration radiation towards the spectroscopy system 120 via the folding mirror 170.

[0167] The inspection arrangement optionally further comprises a black reference element 146. The calibration element 144, and the black reference element 146 are within the field of view of the spectroscopy system (via the polygon mirror 140 and the folding mirror 170) but outside of the inspection zone 104.

[0168] Fig. 4 illustrates in more detail the irradiation unit 114 according to one example embodiment. In this example, the irradiation unit 114 comprises a first illumination device 124 configured to emit the first wavelength range, and a second illumination device 126 configured to emit the second wavelength range. In more detail, the first illumination device 124 is according to this example configured to emit optical radiation in the UV range, and the second illumination device is configured to emit optical radiation in the VIS / NIR range.

[0169] A first optical element, for example a first focusing mirror 125, is configured to receive and redirect radiation originating from the first illumination device 124 towards the scanning element 140. A second optical element, for example a second focusing mirror 127, is configured to receive and redirect radiation originating from the second illumination device 126 towards the scanning element 140.

[0170] A filter element 128 is arranged between the second illumination device 126 and the second focusing mirror 127.

[0171] The filter element 128 is configured to transmit the illumination optical radiation towards the scanning element 140 and block a sub-range of the second wavelength range from directly reaching the scanning element 140, which sub-range of the second wavelength range is outside said illumination optical radiation.

[0172] In other words, the filter element 128 is configured to transmit a first portion of the optical radiation provided by the second illumination device 126, and to block a second portion of the optical radiation provided by the second illumination device

[0173] 126.

[0174] In one example, the filter element 128 is configured to block optical radiation in the VIS wavelength range and transmit optical radiation in the NIR wavelength range.

[0175] The calibration element 144 is configured as described above in connection to Fig. 3. In more detail, the calibration element 144 is adapted to be illuminated by calibration radiation, said calibration radiation being all or a portion of the illuminating optical radiation 222 and all or a portion of the sub-range of the second wavelength range, and the calibration element is adapted to redirect the calibration illumination towards the detector arrangement 120. The calibration element 144 being located within the field of view but outside the inspection zone 104.

[0176] Different optical paths within the irradiation unit 114 of Fig. 4 are schematically illustrated in Fig. 5. The radiation emitted by the first illumination device 124 is directed towards the first focusing mirror 125 along optical path 151 . A portion of the radiation emitted by the second illumination device 126 is transmitted by the filter element 128, and then follows optical path 152 towards the second focusing mirror

[0177] 127. All, or a portion, of the wavelength range emitted by the second illumination device 126 further follows optical path 153 towards the calibration element 144. The radiation that is emitted by said second and optionally also said first light source, and which reaches the calibration element is referred to as calibration radiation. The optical path 153 extends through an opening 154 of the irradiation unit 114.

[0178] The irradiation unit 114 of Fig. 4 and 5 further comprises a shield (not shown in the figures) arranged between the first illumination device 124 and the second illumination device 126 and arranged to block optical radiation except the calibration radiation from illuminating the calibration element 144.

[0179] The irradiation unit 114 as described above in connection to Figs. 4 and 5 comprises two illumination devices, i.e. , the first illumination device 124 and the second illumination device 126. Other configurations with more or fewer illumination devices are however possible. For example, an embodiment in which the irradiation unit 214 comprises a single illumination device 224 is schematically illustrated in Fig. 6. In this case, the single illumination device 224 may be a broadband source, such as, for example, a Xenon arc lamp. As a non-limiting example, the single illumination device may be adapted to provide optical radiation within a wavelength range of 100 nm to 5000 nm. The single illumination device 224 provides optical radiation in the first wavelength range as well as in the second wavelength range. Optical radiation originating from the illumination device 224 is directed to the scanning element 140 (not shown in Fig. 6) by one or more focusing mirrors. In the example of Fig. 6, two focusing mirrors 227a, 227b are used.

[0180] A bandpass filter 228a, 228b is arranged between the illumination device 224 and each focusing mirror 227a, 227b. The filters 228a, 228b block a sub-range of the second wavelength range from directly reaching the scanning element 140, the subrange being outside of the illuminating optical radiation. The filters 228a, 228b thus transmit the illuminating optical radiation. Additionally, the filters 228a, 228b transmit the exciting optical radiation, within the first wavelength range. Thus, only exciting optical radiation, within the first wavelength range, and illuminating optical radiation, within the second wavelength range, are transmitted by the filters 228a, 228b.

[0181] The irradiation unit 214 is configured to direct calibration radiation towards a calibration element 244. The calibration element 244 is adapted to be illuminated by all or a portion of the illuminating optical radiation, and to be illuminated by all or a portion of the sub-range of the second wavelength range of the irradiation unit 114. In other words, the calibration element 244 is illuminated by the radiation emitted by the illumination device, possibly after this radiation has passed a further filter (not shown). The radiation emitted by the irradiation unit 214 which reaches the calibration element is referred to as calibration radiation. Optical radiation from the illumination device 224 is preferably not filtered by the filter 228a, 228b before reaching the calibration element 244.

[0182] A folding mirror 170, having the same function as described for previous embodiments, is also visible in Fig. 6.

[0183] An example of the filtering provided by filters 228a, 228b is schematically illustrated in Figs. 7a and 7b, which show a spectral intensity graph of the optical radiation provided by the illumination device 224. The filters block a sub-range of the second wavelength range, represented by box 701 in Fig. 7b. Thereby, the filters 228a, 228b transmit exciting optical radiation 702 (in this example having a lower wavelength range than the blocked sub-range) and illuminating optical radiation 703 (in this example having a higher wavelength range than the blocked sub-range).

[0184] As illustrated in Fig. 8, the scanning element may comprise two polygon mirrors arranged adjacent to each other, i.e. , a first polygon mirror 140a and a second polygon mirror 140b. The first polygon mirror 140a and the second polygon mirror 140b may have coinciding rotation axes. In this configuration, the irradiation unit 114’ comprises a first illumination device 124’ with associated focusing mirrors 125a, 125b configured to direct the radiation emitted by the first illumination device 124’, i.e., the exciting optical radiation, towards the first polygon mirror 140a. The irradiation unit 114’ further comprises a second illumination device 126’ with associated focusing mirrors 127a, 127b configured to direct the radiation emitted by the second illumination device 126’, i.e., the illuminating optical radiation, towards the second polygon mirror 140b.

[0185] Thus, the first polygon mirror 140a is configured to sweep the exciting optical radiation over the inspection zone 104 and the second polygon mirror is configured to sweep the illuminating optical radiation over the inspection zone 104.

[0186] The fluorescent and / or phosphorescent radiation emitted by EM-excitable items 102 in the inspection zone 104, as well as the illumination response provided by the EM-excitable items 102 in the inspection zone 104 is received by the first 140a and / or second 140b polygon mirror and directed to the spectroscopy system 120, optionally via a folding mirror 170. The spectroscopy system 120 may be arranged as described above in connection to Fig. 3.

[0187] Arrangements comprising two adjacent polygon mirrors such as described above are suitable for use in a wide variety of scanning and classification systems, including those having a different configuration compared to what is described in the present disclosure. Using two polygon mirrors increases the mirror area available for detection and illumination. For instance, the light output may be doubled by using two polygon mirrors, e.g., for sorters with extremely high spatial and spectral resolution. Different illumination types may be combined. Thus, the illumination directed to the two polygon mirrors may comprise partially or completely overlapping wavelength ranges, or separate wavelength ranges. A method of detecting and analysing EM-excitable items in a flow through an inspection zone according to the present disclosure is illustrated by the flow chart of Fig. 9.

[0188] The method comprises transporting 502 EM-excitable items in a flow through an inspection zone. The method further comprises an irradiating step 504. In particular, the method comprises irradiating, by an irradiation arrangement, the EM- excitable items when present in the inspection zone with optical radiation. In other words, the irradiation arrangement irradiates the inspection zone with optical radiation, and any EM-excitable items present in the inspection zone are irradiated by the optical radiation.

[0189] The optical radiation comprises: a first wavelength range comprising exciting optical radiation selected to cause the EM-excitable items to emit fluorescent and / or phosphorescent radiation, and a second wavelength range comprising illuminating optical radiation and calibration optical radiation, which illuminating optical radiation is different from said exciting optical radiation and is selected to cause the EM-excitable items to provide an illumination response corresponding to item-specific signatures of the EM- excitable items, wherein the illumination response is a portion of said illuminating optical radiation being reflected, transmitted and / or scattered by said EM-excitable items.

[0190] In more detail, the irradiating step 504 comprises filtering 504a, by a filter, the second wavelength range, to transmit the illuminating optical radiation but block a sub-range of the second wavelength range.

[0191] The irradiating step 504 further comprises directing 504b the exciting optical radiation and the illumination optical radiation towards a scanning element, and redirecting 504c, by the scanning element, the exciting optical radiation and the illumination optical radiation towards the inspection zone.

[0192] The irradiating step 504 also comprises directing 504d calibration optical radiation towards a calibration element arranged outside the inspection zone, the calibration optical radiation comprising at least a part of the second wavelength range. The method further comprises redirecting 504e, by the calibration element, all or a portion of the calibration optical radiation towards a detector unit. The detector unit has a field of view covering the inspection zone and the calibration element.

[0193] A detection step 506 comprises the detector unit detecting 506a the emitted fluorescent and / or phosphorescent radiation, detecting 506b the illumination response, and detecting 506c calibration optical radiation redirected by the calibration element.

[0194] The illuminating optical radiation is transmitted towards the scanning element while the calibration optical radiation is blocked from reaching the scanning element. The sub-range of the second wavelength range is outside the wavelength range of the illuminating optical radiation. The calibration optical radiation comprises all or a portion of the illuminating optical radiation and all or a portion of the sub-range of the second wavelength range.

[0195] The method further comprises calibrating 508 the inspection system’s settings based on the detected calibration optical radiation.

[0196] The method further comprises analysing 510 the EM-excitable items based on a combination of the fluorescent and / or phosphorescent radiation and the itemspecific signatures.

[0197] Optionally, the method further comprises classifying the EM-excitable items into at least two categories based on the analysis 510.

[0198] The method described above may be performed by the inspection arrangement as described above.

Claims

Claims:

1. An inspection arrangement (100) configured to detect and analyse EM-excitable items (102) in an inspection zone (104), the inspection arrangement (100) comprising:• a transport arrangement (108) configured to feed the EM-excitable items in a flow through the inspection zone,• an irradiation arrangement (114) configured to: o provide optical radiation for irradiating the EM-excitable items (102), the provided optical radiation comprising:• a first wavelength range comprising exciting optical radiation selected to cause the EM-excitable items (102) to emit fluorescent and / or phosphorescent radiation, and• a second wavelength range comprising illuminating optical radiation, which illuminating optical radiation is different from said exciting optical radiation and is selected to cause the EM-excitable items (102) to provide an illumination response corresponding to itemspecific signatures of the EM-excitable items (102), wherein the illumination response is a portion of said illuminating optical radiation being reflected, transmitted, and / or scattered by said EM- excitable items (102), and• a scanning element (140),• an optical arrangement (142a, 142b, 142c, 142d) configured to direct the exciting optical radiation and the illuminating optical radiation towards the scanning element (140),• a detector arrangement (120) having a field of view covering at least the inspection zone, the detector arrangement (120) being configured to detect the emitted fluorescent and / or phosphorescent radiation and to detect the provided illumination response corresponding to item-specific signatures, and• a processing unit (113) configured to detect and analyse at least one of the EM- excitable items (102) present in the inspection zone (104) based on a combination of the fluorescent and / or phosphorescent radiation and the item-specific signatures, wherein the scanning element (140) is configured to redirect the exciting optical radiation and the illuminating optical radiation of the irradiation arrangement (120) towards the inspection zone (104),the irradiation arrangement (120) comprising:• a filter (128) configured to transmit the illuminating optical radiation towards the scanning element (140) and block a sub-range of the second wavelength range from directly reaching the scanning element (140), which sub-range of the second wavelength range is outside said illuminating optical radiation, and• a calibration element (144) adapted to be illuminated by calibration radiation, said calibration radiation being all or a portion of the illuminating optical radiation and all or a portion of the sub-range of the second wavelength range, and adapted to redirect the calibration illumination towards the detector arrangement (120), the calibration element (144) being located within the field of view but outside the inspection zone (104), wherein the detector arrangement (120) is further configured to detect said illumination redirected by the calibration element (144) and to perform a calibration of said inspection arrangement (100) based on at least said detected illumination reflected by said calibration element (144).

2. The inspection arrangement (100) according to claim 1, wherein the irradiation arrangement (114) comprises a first illumination device (124) configured to emit the first wavelength range, a second illumination device (126) configured to emit the second wavelength range, and a shield arranged between the first and second illumination device (126) and arranged to block optical radiation except the calibration radiation from illuminating the calibration element (124).

3. The inspection arrangement (100) according to claim 1, wherein the scanning element (140) is further configured to redirect the provided fluorescent and / or phosphorescent radiation from the inspection zone (104), and the reflected illumination responses from the inspection zone (104), towards the detector arrangement (120).

4. The inspection arrangement (100) according to any of the claims 1 to 3, wherein the scanning element (140) comprises a polygon mirror configured to sweep the exciting optical radiation and the illuminating optical radiation of the irradiation arrangement (114) over the inspection zone (104).

5. The inspection arrangement (100) according to claim 4, wherein the scanning element (140) comprises two polygon mirrors arranged adjacent to each other, of which one of the polygon mirrors is configured to sweep the exciting optical radiation over the inspection zone (104) and the other of the of the polygon mirrors is configured to sweep the illuminating optical radiation over the inspection zone (104), wherein the two polygon mirrors preferably have coinciding rotation axes.

6. The inspection arrangement (100) according to any previous claim, wherein the exciting optical radiation of the first wavelength range comprises a wavelength XI, where 100 nm < XI < 400 nm, and the illuminating optical radiation of the second wavelength range comprises a X2, where 200 nm < X2 < 5000 nm, preferably 400 nm < X2 < 2000 nm.

7. The inspection arrangement (100) according to any previous claim, wherein the detector arrangement (120) is configured to classify the EM-excitable items (102) in at least two categories based on a combination of the detected florescent and / or phosphorescent radiation, and the detected item specific signature.

8. The inspection arrangement (100) according to claim 7, further comprising a sorting arrangement (112) configured sort out EM-excitable items (102) classified in one of the at least two categories from the flow of EM-excitable items.

9. The inspection system (100) according to any one of the preceding claims, wherein the EM- excitable items optionally are containers and / or portions of containers, and wherein the detected florescent and / or phosphorescent radiation is indicative of a material compositions of the EM-excitable items (102), and the item specific signatures are indicative of residues associated with the EM-excitable items (102), and preferably indictive of contents having been in contact with the EM-excitable items.

10. The inspection arrangement (100) according to any previous claim, wherein the EM-excitable items (102) comprises markers configured to emit the florescent and / or phosphorescent radiation, the markers preferably being implemented in form of at least one of: a paint, a print, a sticker, and / or a label.

11. The inspection arrangement (100) according to any one of claims 8-10, wherein one of said at least two categories corresponds to, or is confined to, food compliant items, and whereinsaid sorting arrangement is configured to sort out the EM-excitable items that are classified as food compliant items from the flow of EM-excitable items (102), wherein the classification as food compliant item is optionally based on the detected florescent and / or phosphorescent radiation indicating that a material composition of the EM-excitable is approved as food compliant, and / or that the detected item specific signature optionally indicating that the EM-excitable item (102) is not to be refused.

12. The inspection arrangement (100) according to any one of claims 8-11, wherein one of said at least two categories corresponds to, or is confined to, non-food compliant items, and wherein said sorting arrangement is configured to sort out the EM-excitable items that are classified as non-food compliant items from the flow of EM-excitable items (102), wherein the classification as non-food compliant item is optionally based on the detected florescent and / or phosphorescent radiation indicating that a material composition of the EM-excitable is approved as food compliant, and / or that the detected item specific signature optionally indicating that the EM-excitable item (102) is non-food compliant.

13. The inspection arrangement (100) according to any one of claims 8-10, wherein one of said at least two categories corresponds to, or confined to, reusable textiles, and wherein said sorting arrangement is configured to sort out the EM-excitable items that are classified as reusable textiles from the flow of EM-excitable items (102), wherein the classification as a reuseable textile is optionally based on the detected florescent and / or phosphorescent radiation indicating that a material composition of the EM-excitable is approved as a reuseable textile, and / or that the detected item specific signature optionally indicates that the EM-excitable item (102) is not to be refused.

14. The inspection arrangement (100) according to any previous claim wherein the item specific signature relates to at least one of reflectivity, size and geometric form, wherein said reflectivity comprises one or a combination of wavelength dependent intensity variations, spatial distribution of the reflected radiation, polarization of the reflected radiation.

15. The inspection arrangement (100) according to any previous claim wherein said transporting arrangement is configured to feed EM-excitable items and non-EM excitable items in a flow through the inspection zone, wherein said illuminating optical radiation is preferably selected to cause the non-EM-excitable items to provide an illumination response corresponding to item-specific signatures of the non-EM-excitable items (102), wherein the illumination response is a portion of said illuminating optical radiation being reflected, transmitted, and / or scattered by said non-EM- excitable items (102), wherein detector arrangement is optionally configured to detect the item-specific signature of the non-EM excitable items based on the item specific signature, wherein the processing unit is optionally configured to detect and analyse at least one of the non-EM-excitable items present in the inspection zone based on the item specific signature.

16. The inspection arrangement (100) according to any one of claims 7-14, further configured to classify non-EM-excitable items in at least one category based on the item specific signature.

17. The inspection arrangement (100) according to claim 15 when dependent on at least claim 8, wherein the sorting arrangement is further configured to sort out also non-EM-excitable items classified in one of the at least one category from the flow of EM-excitable items.

18. A method of detecting and analysing EM-excitable items in a flow through an inspection zone, the method comprising:• transporting (502) EM-excitable items in a flow through an inspection zone,• by an irradiating arrangement, irradiating (504) the EM-excitable items when present in the inspection zone with optical radiation, said optical radiation comprising: o a first wavelength range comprising exciting optical radiation selected to cause the EM-excitable items to emit fluorescent and / or phosphorescent radiation, and o a second wavelength range comprising illuminating optical radiation and calibration optical radiation, which illuminating optical radiation is different from said exciting optical radiation and is selected to cause the EM-excitable items to provide an illumination response corresponding to item-specific signatures of the EM-excitable items, wherein the illumination response is a portion of said illuminating optical radiation being reflected, transmitted and / or scattered by said EM-excitable items, wherein irradiating (504) comprises: o by a filter, filtering (504a) the second wavelength range, to transmit the illuminating optical radiation but block a sub-range,o directing (504b) the exciting optical radiation and the illuminating optical radiation towards a scanning element, and directing () calibration optical radiation towards a calibration element arranged outside the inspection zone, the calibration optical radiation comprising at least a part of the second wavelength range, o by said scanning element, redirecting (504c) the exciting optical radiation and the illuminating optical radiation towards the inspection zone, o by said calibration element redirecting (504d) all or a portion of the calibration optical radiation towards a detector arrangement,• by said detector arrangement having a field of view covering the inspection zone and the calibration element, detecting (506a) the emitted fluorescent and / or phosphorescent radiation, detecting (506b) said illumination response, and detecting (508) calibration optical radiation redirected by the VIS calibration element, wherein the illuminating optical radiation is transmitted towards the scanning element while the calibration optical radiation is blocked from reaching the scanning element, which sub-range of the second wavelength range is outside the wavelength range of said illuminating optical radiation, and wherein the calibration optical radiation comprises all or a portion of the illuminating optical radiation and all or a portion of the sub-range of the second wavelength range, the method further comprising:• calibrating (510) the inspection system's settings based on the detected (516) calibration optical radiation, and• analysing (512) the EM-excitable items based on a combination of the fluorescent and / or phosphorescent radiation and the item-specific signatures.

19. The method according to claim 15, wherein the fluorescent and / or phosphorescent radiation from the inspection zone, and the illumination responses from the inspection zone, are redirected towards the detector arrangement.

20. The method according to claim 15 or 16, wherein the scanning element sweep the redirected exciting optical radiation and the illuminating optical radiation of the irradiation arrangement over the inspection zone.

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