WO2024013671A1 - Installation et procédé d'inspection de produits - Google Patents

Installation et procédé d'inspection de produits Download PDF

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Publication number
WO2024013671A1
WO2024013671A1 PCT/IB2023/057144 IB2023057144W WO2024013671A1 WO 2024013671 A1 WO2024013671 A1 WO 2024013671A1 IB 2023057144 W IB2023057144 W IB 2023057144W WO 2024013671 A1 WO2024013671 A1 WO 2024013671A1
Authority
WO
WIPO (PCT)
Prior art keywords
photodiode
scintillator
rays
face
products
Prior art date
Application number
PCT/IB2023/057144
Other languages
English (en)
Inventor
Alessio MANGHI
Claudio Quarantelli
Original Assignee
Raytec Vision S.P.A.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Raytec Vision S.P.A. filed Critical Raytec Vision S.P.A.
Publication of WO2024013671A1 publication Critical patent/WO2024013671A1/fr

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B07—SEPARATING SOLIDS FROM SOLIDS; SORTING
    • B07C—POSTAL SORTING; SORTING INDIVIDUAL ARTICLES, OR BULK MATERIAL FIT TO BE SORTED PIECE-MEAL, e.g. BY PICKING
    • B07C5/00—Sorting according to a characteristic or feature of the articles or material being sorted, e.g. by control effected by devices which detect or measure such characteristic or feature; Sorting by manually actuated devices, e.g. switches
    • B07C5/34—Sorting according to other particular properties
    • B07C5/3416—Sorting according to other particular properties according to radiation transmissivity, e.g. for light, x-rays, particle radiation
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
    • G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
    • G01T1/16—Measuring radiation intensity
    • G01T1/20—Measuring radiation intensity with scintillation detectors
    • G01T1/2018—Scintillation-photodiode combinations
    • G01T1/20181—Stacked detectors, e.g. for measuring energy and positional information
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V5/00—Prospecting or detecting by the use of ionising radiation, e.g. of natural or induced radioactivity
    • G01V5/20—Detecting prohibited goods, e.g. weapons, explosives, hazardous substances, contraband or smuggled objects
    • G01V5/22—Active interrogation, i.e. by irradiating objects or goods using external radiation sources, e.g. using gamma rays or cosmic rays
    • G01V5/224—Multiple energy techniques using one type of radiation, e.g. X-rays of different energies

Definitions

  • the present invention relates to an inspection plant for inspecting products, in particular but not exclusively food products.
  • the food products could be plants, fruits, vegetables, etc.
  • Inspection plants are known which analyse the shape, colour, size of the food products so as to identify those that do not comply with the preset standards.
  • X-ray sensors are also known for detecting a shape of an object and used for example to inspect closed suitcases in airports or at the entrance to high-security areas. This is to identify and prevent the access of weapons, explosives, etc.
  • Such x-ray sensors comprise an x-ray emitter and an x-ray receiving system; they thereby allow to outline the shape of the object.
  • Dual energy sensors are also known in which there is a first sensor to detect higher energy X-rays and a second sensor to detect lower energy X-rays. It is thereby possible to improve the contrast of the image of the detected shape and to have more information related to the density and/or other properties of the material of which the object under examination is constituted.
  • dual energy X-ray receivers which are provided with an electronic board comprising a printed circuit having a first and a second face.
  • the first face is turned towards the x-ray emitter, the second face is turned towards the opposite direction.
  • a first photodiode extends starting from the first face and moving away from the board; a second photodiode extends starting from the second face and moving away from the board.
  • the first and the second photodiode extend aligned along the same direction.
  • the first photodiode has an end which is spaced from the board covered by a first scintillator.
  • the second photodiode has an end which is spaced from the board covered by a second scintillator.
  • the scintillators if struck by X-rays, emit a light pulse that is then detected by the photodiode to which they are associated. To detect two different energy ranges, the scintillators are different in composition and/or thickness. When described with reference to the first and the second photodiode, it can be advantageously repeated for a plurality of pairs of photodiodes which then come to define a specific array.
  • a drawback of such a solution is that it is difficult to detect low energies because they are attenuated or absorbed by the scintillator.
  • a further drawback is related to the fact that the scintillator causes scattering and thus reduces accuracy.
  • the technical task underlying the present invention is to propose an inspection plant and a method for inspecting products which allows to optimise the 'dual energy' operation and to improve sensor accuracy.
  • - figure 1 shows an inspection plant according to the present invention
  • - figure 2 shows a detail of a component of the inspection plant of figure 1 ;
  • FIG. 3 shows a schematic view of such a component.
  • reference numeral 1 denotes a plant for inspecting products, in particular food products, for example but not limited to plants, vegetables, fruits.
  • the plant is more generally usable for products to be selected in which there is a detectable difference in attenuation of the transmitted energy spectra.
  • the inspection plant 1 comprises a conveying line 2 for conveying products.
  • the conveying line 2 may for example comprise a movable solid support, such as a conveyor belt. Such a conveying could also occur in another manner: in aerial suspension, in a liquid stream, etc.
  • the inspection plant 1 may comprise an inspection means 3 for inspecting products in transit along the conveying line 2.
  • the inspection means 3 comprises X-ray emitting means 31.
  • Such an emitting means 31 is well known in the technical field and therefore not further described.
  • the emitting means 31 comprises X-ray detection means 32.
  • the means 32 is dual energy detection means 32.
  • the inspection means 3 are substantially stationary. In particular, they do not change orientation with respect to the conveying line.
  • At least one part of the conveying line 2 is operatively interposed between said X-ray emitting means 31 and said X-ray detection means 32.
  • at least one part of the conveying line 2 transits between the emitting means 31 and the detection means 32.
  • the emitting means 31 and the detection means 32 lie one above and the other below a same part of the conveying line 2.
  • the detection means 32 comprises an electronic board 320. It is a substantially two-dimensional element.
  • the board 320 has a thickness less than 2 millimetres.
  • Such an electronic board 320 comprises a printed circuit. It is also known as a PCB.
  • the electronic board 320 comprises a first and a second face 321 , 322 that are turned in opposite directions. Suitably they are flat faces.
  • the printed circuit board is obtained at least in part on the first and on the second face 321 , 322.
  • the first face 321 faces the X-ray emitting means 31 .
  • the first face 321 faces the conveying line 2.
  • the first face 321 intercepts the x-rays before the second face 322.
  • the detection means 32 comprises a first photodiode 323 obtained on the first face 321.
  • the detection means 32 comprises a second photodiode 324 obtained on the second face 322.
  • the first and second photodiodes 323, 324 are of the same type.
  • the first and second photodiodes 323, 324 are identical to each other.
  • a scintillator 325 faces the second photodiode 324.
  • Such a scintillator 325 if struck by X-rays, generates a light signal detectable by the second photodiode 324.
  • a signal is not detectable by the first photodiode 323 (they are located on two opposite sides of the electronic board 320).
  • the fact that the scintillator 325 faces the second photodiode 324 makes it possible to optimise the signal detection.
  • the second photodiode 324 is thereby struck by the light emitted by the portion of the scintillator facing it without signal losses due to the absorption of the latter.
  • the first and the second photodiode 323, 324 connect to the electronic board 320 at two points that are located in the same position, but on opposite faces of the board 320.
  • a line orthogonal to the board 320 suitably intersects such two points.
  • the first and the second photodiode 323, 324 extend longitudinally along opposite directions and a same direction away from the board 320.
  • the first and second photodiodes 323, 324 protrude away from the board 320 by less than 5 millimetres.
  • the first and the second photodiode 323, 324 extend along a same line away from the board 320.
  • the first photodiode 323 defines an X-ray detector with a lower energy level than those intended to be detected by a detector group 327 comprising the second photodiode 324 and the scintillator 325.
  • the first photodiode 323 therefore allows to detect X-rays with a lower energy level than those detected by the second photodiode 324 with the aid of the scintillator 325.
  • a scintillator 325 is absent at the first photodiode 323. Therefore, no scintillator faces or is in contact with the first photodiode 323. In particular, no scintillator faces the first face 321 or is located interposed between the board 320 and the emitting means 31 .
  • the first photodiode 323 is therefore not operatively associated with a scintillator.
  • the first photodiode 323 performs a direct conversion of the X-rays into an electrical pulse.
  • the Applicant has verified that such a direct conversion typically occurs with X-rays at lower energy levels.
  • the first photodiode (which suitably is/comprises a silicon junction PN) allows to directly convert low-energy photons (below 50 keV, preferably below 30 keV) into electrons while being insensitive to higher energies.
  • the first photodiode 323 may comprise silicon that generates an electrical signal if struck by X-rays (although the choice of silicon is advantageous, it is not necessary since there are also other materials that allow this).
  • the scintillator 325 is spaced apart from the second photodiode 324. Therefore, the scintillator 325 and the second photodiode 324 are not in direct contact with each other. Suitably, there is a space occupied by ambient air between the scintillator 325 and the second photodiode 324.
  • the scintillator 325 is in direct contact with the second photodiode 324. In particular, they are in contact with each other. Suitably, the scintillator 325 adheres to an end of the second photodiode 324. The scintillator 325 and the second photodiode 324 are suitably glued to each other. If necessary, the second photodiode 324 and the scintillator 325 can be mutually supported on each other (without gluing or other constraint).
  • the scintillator 325 may be interposed between the second photodiode 324 and a reflective surface 328 (e.g., a mirror).
  • a reflective surface 328 e.g., a mirror
  • the material with which the scintillator 325 is composed can be traversed in part by photons of visible light (such as the light it emits by itself) and its thickness usually being reduced, the aforementioned expedient allows the intensity of the emitted light to be further increased. Most of the photons emitted from the surface of the scintillator 325 turned towards the reflective surface 328 are then projected backward in the direction of the second photodiode 324 which detects the high energies.
  • the scintillator 325 is removable with respect to the second photodiode 324 and the electronic board 320. This facilitates periodic maintenance, being able to intervene on a specific component.
  • the first photodiode 323, the second photodiode 324 define a modular pair which repeats along the board 320.
  • this modular pair is repeated identically along a straight line parallel to the faces of the board 320.
  • a scintillator can be associated with the second photodiode of each modular pair.
  • the modular pairs can be arranged according to any geometry: single or adjacent rows, matrix, arbitrary shape.
  • the first photodiode 323, the second photodiode 324, and the scintillator 325 associated with the second photodiode 324 define a modular set of three which repeats along the board 320.
  • the set of scintillators can be a single piece or several elements in succession.
  • the first photodiodes form at least a first row in combination.
  • all of the second photodiodes form a row or rows in combination.
  • the scintillators form one or more rows in combination.
  • one or more of the features described for the first photodiode 323 may be repeated for all the first photodiodes.
  • one or more features described for the second photodiode may be repeated for all the second photodiodes.
  • one or more features described for the scintillator 325 may be repeated for all the scintillators.
  • all the scintillators are located in the same half-space relative to a plane on which the board 320 lies (and identified by the substantially two-dimensional board 320).
  • the inspection plant comprises a first and a second row of photodiodes on opposite faces of a single PCB (printed circuit).
  • the two rows are perfectly superimposed on the two faces.
  • the row of photodiodes in the upper part will be left without a scintillator, thus exposed directly to the X-rays, the lower row will have a scintillator layer capable of emitting visible light.
  • This scintillator is placed as close as possible to the photodiode (if possible attached and glued), the photodiode will thus detect the light emitted by the scintillator in the upper part thereof, i.e. , the part most exposed to the X-rays.
  • the electronic board 320 comprises filtering means 326.
  • the filtering means 326 filters a part of the X-rays and allows the transit of a part of the X-rays.
  • the filtering means 326 selectively attenuates some X-rays.
  • the filtering means 326 can therefore be defined as means for selectively attenuating the X-rays. Copper, which is normally used in the construction of PCBs, significantly attenuates the intensity of the photons selectively.
  • the filtering means 326 acts as a barrier to the X-rays having a first energy range.
  • the X-rays having a second energy range overcome such a barrier and can be intercepted by the scintillator 325.
  • the filtering means 326 is made of a metal material.
  • the means 326 comprises a layer interposed between the first and the second face 321 , 322. Such a layer is preferably made of a metal material, advantageously comprising copper or an alloy thereof.
  • the first photodiode 323 could be replaced more generally with a first element for the direct conversion of X-rays.
  • the second photodiode 324 could be replaced with another photodetector element.
  • An object of the present invention is also a sorting plant 10 for sorting products.
  • a sorting plant 10 comprises an inspection plant 1 having one or more of the features described above.
  • the sorting plant 10 further comprises means 11 for removing products from the conveying line 2 on the basis of information from the detection means 32.
  • the removal means could be of various kinds: for example, the product to be removed could be intercepted and diverted by a mechanical element, a fluid jet, etc.
  • a further object of the present invention is a method for inspecting products, for example, but not limited to, food products. Such a method is advantageously implemented by an inspection plant 1 having one or more of the features described above.
  • the method conveniently comprises the steps of: i) letting products transit along a conveying line 2; advantageously the products are advanced along a solid support, such as a conveyor belt; ii) emitting, through emitting means 31 , X-rays towards said products transiting along a section of the conveying line 2; iii) intercepting, through detection means 32, the X-rays emitted by the emitting means 31 ; this occurs after the X-rays have crossed the conveying line 2 (and therefore have been able to intercept a part of the products).
  • the step of intercepting the X-rays comprises the sub-steps of:
  • the second photodiode 324 is therefore a photodiode that intercepts higher energy X-rays and the first photodiode 323 intercepts the lower energy X-rays.
  • the first and the second photodiode 323, 324 are applied to a first and a second face 321 , 322 of an electronic board 320, respectively.
  • first and the second face 321 , 322 are turned in opposite directions.
  • the first face 321 is suitably turned towards the emitting means 31.
  • the X-rays cross the board 320 from the first face 321 towards the second face 322.
  • the first photodiode 323 performs a direct conversion of the X-rays into an electrical pulse without using a scintillator 325.
  • the second photodiode 324 instead detects the light emitted by the scintillator 325 when the latter is struck by the X-rays.
  • the X-rays are at least partially filtered by a filtering layer present in the board 320. Therefore, the second photodiode 324 will be struck by X-rays having a higher energy. Therefore, the second photodiode 324 can detect higher energy X-rays.
  • the present invention achieves important advantages. Firstly, it allows to obtain a solution in which the components are optimised and at the same time allows to improve the detection of low energies because the absence of a scintillator at the first photodiode does not attenuate them. Furthermore, the absence of the scintillator in such an area reduces the scattering phenomenon.

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  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • High Energy & Nuclear Physics (AREA)
  • General Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Molecular Biology (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geophysics (AREA)
  • Analysing Materials By The Use Of Radiation (AREA)

Abstract

La présente invention concerne une installation d'inspection conçue pour inspecter des produits et comprenant : i) une ligne de transport (2) conçue pour transporter des produits ; et ii) des moyens d'inspection (3) conçus pour inspecter des produits en transit le long de la ligne de transport (2). Lesdits moyens d'inspection (3) comprennent des moyens d'émission de rayons X (31) et des moyens de détection de rayons X à double énergie (32). Au moins une partie de la ligne de transport (2) est fonctionnellement intercalée entre lesdits moyens d'émission de rayons X (31) et lesdits moyens de détection de rayons X (32). Les moyens de détection (32) comprennent : - une carte électronique (320) comportant des première et seconde faces (321, 322) qui sont orientées dans des directions opposées, la première face (321) étant orientée vers les moyens d'émission de rayons X (31) ; - une première photodiode (323) formée sur la première face (321) ; - une seconde photodiode (324) formée sur la seconde face (322) ; et - un scintillateur (325) orienté vers la seconde photodiode (324). La première photodiode (323) définit un détecteur de rayons X ayant un niveau d'énergie inférieur à ceux destinés à être détectés par un groupe de détecteurs (327) comprenant la seconde photodiode (324) et le scintillateur (325). Il n'y a pas de scintillateur au niveau de la première photodiode (323).
PCT/IB2023/057144 2022-07-15 2023-07-12 Installation et procédé d'inspection de produits WO2024013671A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT202200014917 2022-07-15
IT102022000014917 2022-07-15

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WO2024013671A1 true WO2024013671A1 (fr) 2024-01-18

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080240339A1 (en) * 2007-03-28 2008-10-02 Yanfeng Du Energy discriminating detector with direct conversion layer and indirect conversion layer
DE102008013413B4 (de) * 2008-03-10 2010-08-19 Siemens Aktiengesellschaft Röntgendetektor in Schichtbauweise sowie Verfahren zur Erzeugung eines Röntgenbilds
DE102020117484A1 (de) * 2020-07-02 2022-01-05 Smiths Heimann Gmbh Dual-energie-detektor und aufbereitungsverfahren für detektordaten

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080240339A1 (en) * 2007-03-28 2008-10-02 Yanfeng Du Energy discriminating detector with direct conversion layer and indirect conversion layer
DE102008013413B4 (de) * 2008-03-10 2010-08-19 Siemens Aktiengesellschaft Röntgendetektor in Schichtbauweise sowie Verfahren zur Erzeugung eines Röntgenbilds
DE102020117484A1 (de) * 2020-07-02 2022-01-05 Smiths Heimann Gmbh Dual-energie-detektor und aufbereitungsverfahren für detektordaten

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