Product rejection system and method

Abstract

Product rejection system comprising: i) a product conveyor line (2); ii) an inspection means (3) for inspecting products positioned along the conveyor line (2); iii) a removal means (4) for removing some of the products conveyed along the conveyor line (2) on the basis of information provided by the inspection means (3); said inspection means (3) comprising: -a laser emitter (30) which generates a laser beam directed towards the conveyor line (2); -a flat reflection means (32) for reflecting at least a part of the electromagnetic radiation previously reflected by the conveyor line (2); said flat reflection means (32) being physically interposed between the laser emitter (30) and the conveyor line (2); -a fan-out means (31 ) for fanning out the laser beam, physically interposed between the emitter (30) and the flat reflection means (32); -a SWIR spectrometer (34); -a VNIR camera (35); -a separation means (33) for separating the VNIR bands from the SWIR bands; said separation means (33) being positioned downstream of the flat reflection means (32) and upstream of the SWIR spectrometer (34) and the VNIR camera (35).

Description

[0001] DESCRIPTION

[0002] PRODUCT REJECTION SYSTEM AND METHOD

[0003] Technical field

[0004] The present invention relates to a product rejection system and method.

[0005] Prior art

[0006] Systems for rejecting food products are known comprising a vision system which controls means for removing products having defects or bruises from the conveyor line.

[0007] Solutions of the type described in EP3324173 are also known.

[0008] In such a solution, there is a supercontinuum (broad spectrum) laser emitter. It horizontally emits a laser beam which passes through a slot of a parabolic mirror and hits an optical system which deviates it towards the underlying conveyor line. The light reflected by the conveyor line hits the optical system again, which directs it towards the parabolic mirror, which in turn directs it towards a bundle consisting of a central fibre and side fibres. The system then envisages determining the spectrum of the central fibre and the side fibres independently. A drawback of this solution is related to the use of a fibre spectrometer and therefore the difficulty of accurately inspecting the products if the conveyor with the products to be inspected moves at high speeds. A further drawback is related to dimensions.

[0009] Object of the invention

[0010] The object of the present invention is to provide a product rejection system and method which allow to improve the detection of information related to the products. A further important object is to optimise dimensions.

[0011] The stated technical task the specified objects are substantially achieved by a system and a method comprising the technical features disclosed in one or more of the appended claims.

[0012] Brief description of the drawings

[0013] Further features and advantages of the present invention will become more apparent from the indicative and thus non-limiting description of a preferred but non-exclusive embodiment of a system and method, as illustrated in the attached drawings in which:

[0014] - Figure 1 shows a schematic view of a rejection system according to the present invention;

[0015] - Figure 2 shows a detail of the solution of Figure 1 .

[0016] Detailed description of preferred embodiments of the invention

[0017] In the appended drawings, reference number 1 denotes a product rejection system. They are typically food products, for example fruits or vegetables. Suitably, they are discrete and distinct products.

[0018] Such a rejection system 1 comprises a product conveyor line 2. For example, such a conveyor line 2 can comprise a conveyor belt and / or a chute.

[0019] The system 1 comprises an inspection means 3 for inspecting products positioned along the conveyor line 2. The inspection means 3 is intended to detect any defects in the products, for example, unripe, bruised products, with visible surface defects, etc.

[0020] The system 1 further comprises a removal means 4 for removing some of the products conveyed along the conveyor line 2 on the basis of information provided by the inspection means 3. The removal means 4 can for example comprise mechanical diverters or fluid jets (typically of air or gas) which remove a certain product from the conveyor line 2. The removal means 4 is located downstream of the inspection means 3. It is schematically illustrated in Figure 1 (typically it is located even further downstream with respect to the inspection means 3 than exemplified in Figure 1 ; further downstream with reference to the advancement of the products along the conveyor line 2). The removal means 4 can act along a conveyor belt of the conveyor line 2 or at a possible jump to which the products are subjected along the conveyor line 2.

[0021] The inspection means 3 comprises a laser emitter 30 which generates a laser beam directed towards the conveyor line 2. The laser emitter 30 is oriented to generate a laser beam oriented downwards. Suitably, the laser emitter 30 defines a point-like laser source. Only one source for the entire vision band. The emitter 30 emits electromagnetic radiation with a plurality of wavelengths. The emitter 30 is a broad spectrum emitter.

[0022] The laser emitter 30 is a supercontinuum laser emitter. Such a type of emitter, as such, is well known in the art and uniquely defined by such an expression.

[0023] The laser emitter 30 emits electromagnetic radiation ranging from the blue spectrum to SWIR. Typically, the laser emitter emits electromagnetic radiation having wavelengths ranging from 450 nm to 2400 nm.

[0024] The system 1 comprises a flat reflection means 32 of at least a part of the electromagnetic radiation previously reflected by the conveyor line 2. The means 32 reflects electromagnetic radiation coming from the conveyor line 2. The flat reflection means 32 is physically interposed between the laser emitter 30 and the conveyor line 2. The flat reflection means 32 typically comprises a mirror. The mirror faces the conveyor line 2.

[0025] The system 1 comprises a fan-out means 31 for fanning out the laser beam, physically interposed between the emitter 30 and the flat reflection means 32. The means 31 fans out the laser beam by an angle which is preferably comprised between 50° and 80°, advantageously 60° or 75°. In Figure 1 , the fanning out of the beam occurs in a plane orthogonal to the plane of the sheet. Typically, the fan-out means 31 comprises at least one Powell lens 310 (exemplified in Figure 2; in such a figure, the laser coming from the left hits the Powell lens 310 and is fanned out to the right). In an alternative solution, the fan-out means 31 could comprise a Fresnel lens.

[0026] Advantageously, the fan-out means 31 are made of glass. In particular, a Powell glass lens 310 ensures an excellent uniformity and continuity in a very large projection area and the glass allows working with wavelengths in the SWIR range. In particular, the Powell glass lens allows working with wavelengths up to 1700nm.

[0027] Suitably, the Powell lens 310 comprises a convex front area and advantageously a flat rear area. The convex front area is oriented upwards. The flat rear area is oriented downwards. The dimensions of the Powell lens 310 are approximately 6x6x6 millimetres. The light collimated by the laser enters from the curved top and exits fanned out from the lower side.

[0028] The system 1 further comprises an SWIR spectrometer 34. SWIR is the acronym of Short Wave InfraRed. It allows performing a spectrographic analysis of electromagnetic radiation having wavelengths comprised between 900 nm and 1700 nm. Suitably, the spectrometer has 40° vision. The SWIR spectrometer 34 is known as such and is of a commercial type. The system 1 further comprises a VNIR camera 35. VNIR is the acronym of Visible and Near InfraRed. The camera 35 is suitably a linear four- colour VNIR camera (but could also be three or five lines). Suitably, the camera 35 has 45° vision. The VNIR camera 34 is known as such and is of a commercial type.

[0029] The system 1 comprises a separation means 33 for separating the VNIR bands from the SWIR bands. The separation means 33 is positioned downstream of the flat reflection means 32 and upstream of the SWIR spectrometer 34 and the VNIR camera 35. Upstream and downstream are to be considered with reference to the path of the electromagnetic waves from the emitter 30 to the SWIR spectrometer 34 and the VNIR camera 35 (passing through the Powell lens 310, the flat reflection means 32, the conveyor line 2, the separation means 33).

[0030] In the preferred solution, the separation means 33 allows the passage of the SWIR bands while determining a deviation of the VNIR bands. For example, such a deviation occurs upwards. The deviation suitably affects an angle comprised between 70° and 110°.

[0031] Starting from said separation means 33, the SWIR spectrometer 34 and the VNIR camera 35 are arranged along two directrices 340, 350 which form a 90° angle interposed between them. Suitably, the separation means 33 allows the bands to be separated. A further opportunity is to allow the SWIR spectrometer 34 and the VNIR camera 35 to be positioned orthogonal to each other (therefore, without obstacles between the two, facilitating fine adjustment). In such a solution, it acts as a mirror for the VNIR wavelengths and is transparent for the SWIR bands.

[0032] Advantageously, the flat reflection means 32 defines a slot 320 which allows the passage towards the conveyor line 2 of the fanned-out laser beam. Such a slot 320 is a through slot. The slot 320 preferably lies on the vertical of the emitter 30. It crosses the flat reflection means 32 in thickness. Thereby, a coaxial view can be obtained.

[0033] Advantageously, the system 1 can further comprise a first collimator 301 physically interposed between the Powell lens 310 and the flat reflection means 32. The first collimator 301 advantageously allows straightening a beam of rays coming from a source.

[0034] Suitably, the system 1 can further comprise a second collimator 302 interposed between the first collimator 301 and the flat reflection means 32. The flat reflection means 32 is associated with a support 303. The reflecting surface defined by the means 32 involves a first side 304 of such a support 303 (facing the conveyor line 2), while a second side 305 faces the laser emitter 30. The second collimator 302 lies on the second side 305 of the support 303. Suitably, the first collimator 301 is interposed between the laser emitter 30 (or rather the Powell lens 310) and the second collimator 302.

[0035] An object of the present invention is also a product rejection method. The products are typically food products (for example fruits or vegetables; typically they are discrete and separate products). Such a method is suitably implemented by a rejection system 1 comprising one or more of the features described above.

[0036] The method comprises the steps of conveying the products along a conveyor line 2.

[0037] The method comprises the step of analysing the products located along the conveyor line 2 through an inspection means 3.

[0038] The method further comprises a step of removing some of the products conveyed along the conveyor line 2 on the basis of information provided by the inspection means 3. This is implemented by removal means 4 which can be for example mechanical or fluid-dynamic (for example a jet). The step of analysing the products comprises the steps of:

[0039] - emitting a laser beam directed towards the conveyor line 2; this occurs with the emitter 30; the laser beam is preferably directed downwards (typically it is vertical); suitably the laser beam is a supercontinuum laser beam; it is suitably broad-spectrum; this typically occurs at the emitter 30; suitably the conveyor line 2 can comprise a conveyor belt which can possibly be backlit;

[0040] - fanning out the laser beam before it reaches the conveyor line 2; this typically occurs through a Powell lens 310;

[0041] -reflecting, by means of a flat reflection means 32, at least a part of the electromagnetic radiation in turn previously reflected by the conveyor line 2; in fact, the laser beam illuminates the conveyor line 2 and the products conveyed by it and the electromagnetic radiation is at least partially reflected towards the flat reflection means 32; such reflection from the conveyor line 2 to the means 32 occurs upwards; the flat reflection means 32 horizontally redirects such electromagnetic radiation; the means 32 typically comprises a mirror; such a mirror is flat and lies inclined by an angle comprised between 40° and 50° (typically 45°) with respect to the horizontal.

[0042] - separating the VNIR bands from the SWIR bands present in said at least a part of the electromagnetic radiation;

[0043] - analysing the SWIR bands by means of a SWIR spectrometer 34 and analysing the VNIR bands by means of a VNIR camera 35 in order to detect any defects in the products conveyed along the conveyor line 2.

[0044] The present invention achieves important advantages.

[0045] Firstly, it allows optimising the detection of defects in the products under examination. It further allows providing a compact solution.

[0046] The invention thus conceived is susceptible to numerous modifications and variants, all falling within the scope of the inventive concept that characterises it. Furthermore, all the details may be replaced with other technically equivalent elements. All the materials used, as well as the dimensions, may in practice be any whatsoever according to needs.

Claims

CLAIMS1. A product rejection system comprising: i) a product conveyor line (2); ii) an inspection means (3) for inspecting products positioned along the conveyor line (2); iii) a removal means (4) for removing some of the products conveyed along the conveyor line (2) on the basis of information provided by the inspection means (3); said inspection means (3) comprising:-a laser emitter (30) which generates a laser beam directed towards the conveyor line (2);-a flat reflection means (32) for reflecting at least a part of the electromagnetic radiation reflected by the conveyor line (2); said flat reflection means (32) being physically interposed between the laser emitter (30) and the conveyor line (2);-a fan-out means (31 ) for fanning out the laser beam, physically interposed between the emitter (30) and the flat reflection means (32);-a SWIR spectrometer (34);-a VNIR camera (35);-a separation means (33) for separating the VNIR bands from the SWIR bands; said separation means (33) being positioned downstream of the flat reflection means (32) and upstream of the SWIR spectrometer (34) and the VNIR camera (35).

2. The system according to claim 1 , characterised in that said laser emitter (30) is oriented so as to generate a laser beam oriented downwards.

3. The system according to claim 1 or 2, characterised in that said laser emitter (30) is a supercontinuum laser emitter.

4. The system according to any one of the preceding claims, characterised in that said laser emitter (30) emits electromagnetic radiation ranging from the blue spectrum to SWIR.

5. The system according to any one of the preceding claims, characterisedin that said flat reflection means (32) defines a slot (320) that allows the passage towards the conveyor line (2) of the fanned-out laser beam.

6. The system according to any one of the preceding claims, characterised in that said fan-out means (31 ) comprises at least one Powell lens (310).

7. The system according to any one of the preceding claims, characterised in that the separation means (33):- allows the passage of the SWIR bands;- brings about a deviation of the VNIR bands.

8. The system according to any one of the preceding claims, characterised in that, starting from said separation means (33), the SWIR spectrometer (34) and the VNIR camera (35) are arranged along two directrices (340, 350) which form a 90° angle interposed between them.

9. A product rejection method comprising the steps of: i) conveying the products along a conveyor line (2); ii) analysing, through an inspection means (3), the products positioned along the conveyor line (2); iii) removing some of the products conveyed along the conveyor line (2) on the basis of information provided by the inspection means (3); the step of analysing the products comprises the steps of:-emitting a laser beam directed towards the conveyor line (2);-fanning out the laser beam before it reaches the conveyor line (2);-reflecting, by means of a flat reflection means (32), at least a part of the electromagnetic radiation previously reflected by the conveyor line (2);- separating the VNIR bands from the SWIR bands present in said at least a part of the electromagnetic radiation;- analysing the SWIR bands by means of a SWIR spectrometer (34) and analysing the VNIR bands by means of a VNIR camera (35) in order to detect any defects in the products conveyed along the conveyor line (2).

10. The method according to claim 9, characterised in that said laser beam is a supercontinuum laser beam.

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