Device and Method for Inspecting Parisons

Abstract

An apparatus (1) for the inspection of parisons (2) comprises: an inspection zone (10), configured to receive an unordered plurality of parisons (2); an illuminator (3), configured to emit a beam of light directed at the plurality of parisons (2); a detector (4) comprising a camera (41) configured to capture an image of the plurality of parisons (2), wherein the inspection zone is interposed between the illuminator (3) and the detector (4); a control unit (5) configured to process the image captured by the camera (41) to derive an item of diagnostic information regarding the defectiveness of one or more parisons (2) of the plurality of parisons (2), wherein the illuminator (3) includes an emission-polarizing filter (32) and the detector (4) includes a receiving polarizing filter (42).

Claims

1-23. (canceled)

24. An apparatus for the inspection of parisons, comprising: an inspection zone, configured to receive an unordered plurality of parisons; an illuminator including a light source configured to emit a beam of light directed at the plurality of parisons located in the inspection zone; a detector comprising a camera configured to capture an image of the plurality of parisons, located in the inspection zone, wherein the inspection zone is interposed between the illuminator and the detector; and a control unit configured to process the image captured by the camera to derive a diagnostic information regarding the defectiveness of one or more parisons of the plurality of parisons; wherein the illuminator includes an emission-polarizing filter configured to intercept the beam of light emitted by the light source and to generate a polarized light beam, and in that the detector includes a receiving polarizing filter configured to receive the polarized light beam, so that the plurality of parisons, in the inspection zone, is operatively interposed between the emission-polarizing filter and the receiving polarizing filter.

25. The apparatus according to claim 24, wherein the emission-polarizing filter is a circular polarizing filter.

26. The apparatus according to claim 25, wherein the receiving polarizing filter includes a first linear polarizing filter portion, having a first polarizing direction and a second linear polarizing filter portion, having a second polarizing direction, different from the first polarizing direction.

27. The apparatus according to claim 26, wherein the receiving-polarizing filter includes four linear polarizing filter portions, having respective polarizing directions angularly spaced at 45° from each other.

28. The apparatus according to claim 26, wherein the receiving-polarizing filter includes a plurality of units and, for each unit of the plurality of units, a respective plurality of linear polarizing filter portions, each having a respective polarizing direction which is different from the others, and wherein, for each linear polarizing filter portion, the camera includes a photoelectric converter section including a pair of photodiodes.

29. The apparatus according to claim 24, wherein the image captured by the camera depicts the plurality of parisons, and wherein the control unit is configured to derive, from the captured image, a plurality of derived images, each representing a respective parison of the plurality of parisons and to process each derived image of the plurality of derived images in order to generate the diagnostic information.

30. The apparatus according to claim 24, comprising a conveyor, configured to receive the parisons of the plurality of parisons and to convey them to the inspection zone in unordered fashion.

31. The apparatus according to claim 30, wherein the conveyor includes an at least partly transparent surface configured to supportably receive the plurality of parisons and wherein the inspection zone is defined along the conveyor.

32. The apparatus according to claim 31, wherein the conveyor includes a carousel and wherein the carousel includes a plate defining the at least partly transparent surface.

33. The apparatus according to claim 32, wherein the carousel includes a rotary frame and a plurality of at least partly transparent plates, connected to the frame and defining the at least partly transparent surface.

34. The apparatus according to claim 32, wherein the at least partly transparent plate is interposed between the illuminator and the detector.

35. The apparatus according to claim 34, wherein the illuminator is mounted under the carousel and the detector is mounted above the carousel, with respect to a vertical direction parallel to the weight force.

36. The apparatus according to claim 32, wherein the illuminator and the detector are at stationary positions relative to the carousel.

37. The apparatus according to claim 30, wherein the conveyor includes a carousel, mounted to rotate about a vertical axis, so that the of parisons are transported by the carousel along a curved path around the vertical axis, and wherein the inspection zone is defined along the curved path.

38. The apparatus according to claim 30, comprising a collection container, wherein the conveyor is configured to convey the plurality of parisons to the collection container, wherein the camera is configured to capture images of the parisons of the plurality of parisons as soon as they are released from the conveyor, so the inspection zone is defined between the conveyor and the collection container.

39. The apparatus according to claim 24, comprising a container having an at least partly transparent bottom, configured to receive the plurality of parisons, wherein the container is positionable at an operating position between the detector and the illuminator, wherein, at the operating position of the container, the plurality of parisons is operatively interposed between the emission-polarizing filter and the receiving polarizing filter.

40. The apparatus according to claim 24, comprising: an additional inspection zone, configured to receive the unordered plurality of parisons, upstream or downstream of the inspection zone; an additional light source configured to emit a beam of light directed at the plurality of parisons located in the additional inspection zone; and an additional camera, configured to capture an additional image of the plurality of parisons located in the additional inspection zone, wherein the plurality of parisons in the additional inspection zone is operatively positioned between the additional light source and the additional camera, wherein the control unit is configured to process the additional image captured by the additional camera to derive a diagnostic information regarding a colour quality of the one or more parisons.

41. A method for the inspection of parisons, comprising the following steps: receiving an unordered plurality of parisons in an inspection zone; illuminating the parisons of the plurality of parisons; capturing an image of the plurality of illuminated parisons in the inspection zone, wherein the image is captured by a camera; and processing the image captured by the camera to derive a diagnostic information regarding the defectiveness of one or more parisons of the plurality of parisons; wherein the parisons of the plurality of parisons in the inspection zone are illuminated with a beam of polarized light.

42. The method according to claim 41, wherein the step of illuminating includes the following sub-steps: generating a beam of non-polarized light through a light source; intercepting the beam of light on an emission-polarizing filter, interposed between the light source and the plurality of parisons, to generate the beam of polarized light; and receiving the beam of polarized light on a receiving polarizing filter, interposed between the parison and the camera; wherein the plurality of parisons in the inspection zone is operatively interposed between the emission-polarizing filter and the receiving polarizing filter.

43. The method according to claim 42, wherein: the emission-polarizing filter is a circular polarizing filter; and the receiving-polarizing filter includes a plurality of linear polarizing filter portions, each having a respective polarizing direction which is different from the others.

44. The method according to claim 41, comprising a step of transporting the plurality of parisons on a conveyor having an at least partly transparent surface, wherein the inspection zone is defined along the conveyor, so the parisons are inspected while they are being transported by the conveyor.

45. The method according to claim 41, wherein, during inspection, the parisons are transported along a curved path at a constant height.

46. The method according to claim 41, wherein the parisons are transported through a carousel along a curved path around a vertical axis and are inspected while they move along the curved path.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0059] These and other features will become more apparent from the following detailed description of a preferred embodiment, illustrated by way of non-limiting example in the accompanying drawings, in which:

[0060] FIG. 1 schematically illustrates an optical inspection apparatus according to this disclosure;

[0061] FIG. 2 shows a possible embodiment of the optical inspection apparatus of FIG. 1;

[0062] FIG. 3 shows a possible embodiment of the optical inspection apparatus of FIG. 1;

[0063] FIGS. 4 and 5 show the apparatus according to the embodiment of FIG. 2 or of FIG. 3 in respective side views;

[0064] FIG. 6 shows the apparatus according to the embodiment of FIG. 2 in a top view;

[0065] FIG. 7 shows a possible embodiment of the optical inspection apparatus of FIG. 1;

[0066] FIG. 8 shows a possible embodiment of the optical inspection apparatus of FIG. 1;

[0067] FIG. 9 shows a detail of the optical inspection apparatus of FIG. 1.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

[0068] With reference to the accompanying drawings, the numeral 1 denotes an apparatus for optical inspection of parisons (or, more generally speaking, of objects) 2. The apparatus 1 comprises an inspection zone 10, configured to receive an unordered plurality of parisons 2 (or flow of parisons 2). It should be noted that the apparatus 1 is configured to receive the parisons 2 from a forming machine in which the parisons are formed.

[0069] The apparatus 1 comprises an illuminator 3. The illuminator 3 includes a light source 31. The light source 31 is configured to emit a beam of light directed at the inspection zone 31. The illuminator 3 includes an emission-polarizing filter 32. The emission-polarizing filter 32 is interposed between the light source 31 and the inspection zone 10 to intercept the light beam emitted by the light source 31. The emission-polarizing filter 32 is a circular filter, configured to polarize the light in a plurality of directions (that is, in all directions).

[0070] The apparatus 1 comprises a detector 4. The detector 4 comprises a camera 41. The camera 41 is configured to capture an image of the unordered plurality parisons 2 positioned in the inspection zone 10. The inspection zone 10 is located between the illuminator 3 and the detector 4, so that the image of the parison captured is backlit (that is, against the light). The detector 4 also includes a receiving polarizing filter 42, interposed between the camera 41 and the inspection zone 10. Thus, the beam of light emitted by the light source 31 is filtered by the emission-polarizing filter 32, by the parisons 2 and by the receiving polarizing filter 42.

[0071] Preferably, the camera 41 and the receiving polarizing filter 42 are integrated with each other inside the detector 4; the detector 4 therefore defines a solid-state imaging device. More specifically, the receiving polarizing filter 42 includes a plurality of units 420, each of which includes a plurality of linear polarizing filter portions: a first portion 421, a second portion 422, a third portion 423 and fourth portion 424. The first portion 421 is configured to polarize the light in a first direction D1. The second portion 422 is configured to polarize the light in a second direction D2. The third portion 423 is configured to polarize the light in a third direction D3. The fourth portion 424 is configured to polarize the light in a fourth direction D4. The first, second, third and fourth polarizing directions D1, D2, D3 and D4 are different from each other. More specifically, the second direction D2 is inclined at 45° relative to the first direction D1. The fourth direction D4 is inclined at 45° relative to the second direction D2. The third direction D3 is inclined at 45° relative to the fourth direction D4. It should be noted that each polarizing filter portion 421, 422, 423, 424 may be shaped like a flat lens or like a hemispherical lens.

[0072] For each linear polarizing filter portion 421, 422, 423, 424, the camera 41 includes a photoelectric converter section; the photoelectric converter section is symmetrical. Preferably, the photoelectric converter section includes a pair of photodiodes 411, 412. Preferably, the photoelectric converter section may include more than one pair of photodiodes 411,412. Thus, for each polarizing filter portion 421, 422, 423, 424, the camera 41 includes at least a first photodiode 411 and a second photodiode 412.

[0073] The apparatus 1 comprises an additional inspection zone 100. The additional inspection zone 100 is configured to receive the unordered plurality (or flow) of parisons 2, upstream or downstream of the inspection zone 10. The apparatus 1 comprises an additional light source 310 configured to emit a beam of light directed at the additional inspection zone 100. The apparatus 1 comprises an additional camera 410 configured to capture images of the plurality of parisons 2 located in the additional inspection zone 100. The additional camera 410 is not provided with polarizing filters. The additional light source 310 is not provided with polarizing filters.

[0074] The apparatus 1 comprises a control unit 5. The control unit 5 is connected to the camera 41 to receive the images captured by the camera. The control unit 5 is connected to the additional camera 410 to receive the images captured by the camera. The control unit 5 is configured to process the images received from the camera 41 and/or from the additional camera 410 to derive an item of diagnostic information regarding any defects of one or more of the parisons 2. More specifically, from the images captured by the camera 41, the control unit 5 derives defects in the body and thread of the parisons 2, such as shape irregularities or abnormal stresses in the material; from the images captured by the additional camera 410, the control unit 5 derives defects in the colour of the parisons 2.

[0075] In an embodiment, the apparatus 1 comprises a conveyor 6. The conveyor 6 is configured to receive the parisons 2 and to convey them in unordered fashion to the inspection zone 10 and/or to the additional inspection zone 100.

[0076] More specifically, in an embodiment, the conveyor 6 is configured feed the parisons 2 along a path; the inspection zone 10 and/or the additional inspection zone 100 are positioned along that path. In an embodiment, the conveyor 6 itself advances along the path with the parisons 2 supported thereon. The conveyor 6 may move continuously or intermittently, with periods of movement alternated with periods of stopping.

[0077] It should be noted that the surface of the conveyor 6 is configured to supportably receive the parisons 2 and is at least partly transparent, so that the illuminator 3 can be mounted on a first side of the conveyor 6 and the detector 4 can be mounted on a second side of the conveyor 6, opposite the first side, to capture images of the parisons 2 against the light.

[0078] In an embodiment not illustrated, the conveyor 6 could be a partly transparent belt (made of transparent rubber, for example). The belt may include elongate features (that is, grooves) configured to urge the parisons 2 to be oriented along a certain direction. In the latter case, the parisons 2 are received on the belt in unordered fashion but are subsequently (at least partly) ordered. The belt may advance downwardly (that is to say, it receives the parisons at a first point, at a first vertical height, and releases them at a second point, at a second vertical height, lower than the first height), upwardly (that is to say, it receives the parisons at a first point, at a first vertical height, and releases them at a second point, at a second vertical height, higher than the first height) or at a constant height. The inspection zone could be defined along the belt or downstream of it (that is, the parisons 2 could be inspected the moment they drop off the belt).

[0079] Whatever the case, the parisons are intercepted and transported without necessarily being singulated or spaced in any particular manner, which means the flow of parisons remains unordered.

[0080] In the example embodiment in which the conveyor (belt or other) moves the parisons upwards - that is, from a lower level to a higher level -inspection (through polarized light) occurs while the parisons are moving upwards; in this example, the conveyor also includes abutment members (preferably transparent). The abutment members may be disposed transversely or obliquely to a conveying (feeding) direction of the conveyor. The abutment members are configured to intercept the parisons to make it easier for them to be transported upwards; the abutment members may also be configured to interact with the parisons (thanks to the fact that the abutment members move as one with the conveyor) in order to orient them along a predetermined direction (for example, parallel to the feed direction). In this case, linear polarization could be sufficient, without necessarily using circular polarization.

[0081] In another embodiment, not illustrated, the conveyor 6 could include a plurality of panels, made of glass, Plexiglas or other transparent material, which move on a chain conveyor.

[0082] In an embodiment, the conveyor 6 comprises a rotary carousel 61. The carousel 61 includes a frame 612 and at least one transparent (or partly transparent) plate 611 mounted on the frame 612. The parisons 2 are supported in unordered fashion on the at least one plate 611.

[0083] More specifically, in an embodiment, the carousel 61 includes a single plate 611, having the shape of a disc (and thus extending for 360° on the carousel 61). In another embodiment, the carousel 61 includes a plurality of plates 611, each of which occupies an angular sector of the carousel 61.

[0084] The apparatus 1 (or the conveyor 6) comprises an infeed belt 63, configured to feed the parisons 2 to the conveyor 6; in an embodiment, the belt 63 does not form part of the apparatus 1 but of the forming machine which forms the parisons 2. In the case where the conveyor 6 includes the carousel 61, the apparatus 1 also comprises a guide piece 62. The guide piece 62 is configured to guide the parisons 2 from the belt 63 onto the carousel 61; more specifically, the parisons 2 slide down onto the surface of the guide piece 62. The guide piece 62 feeds the parisons 2 onto a receiving zone of the carousel. The inspection zone 10 and the additional inspection zone 100 are located downstream of the receiving zone. These zones are at fixed positions and the carousel 61, as it rotates, moves the parisons 2 from the receiving zone to the inspection zone 10 and/or to the additional inspection zone 100. The illuminator 3 is positioned under the carousel 61 and the detector 4 is positioned above the carousel 61 at the illuminator 3. Similarly, the additional light source 310 is positioned under the carousel 61 and the additional camera 410 is positioned above the carousel 61 at the additional light source 310. A lower surface of the guide piece 62 acts as a stop for the parisons 2 which have moved all the way round the carousel 61 and which drop off the carousel 61 when they encounter the guide piece 62. The parisons 2 leave the carousel 61 at an exit zone. The apparatus 1 comprises a collection container 71 which is positioned under the carousel 61 at the exit zone where the parisons 2 leave the carousel 61 and which is configured to collect the inspected parisons 2. It should be noted that an additional conveyor belt may be provided in place of the collection container 71; thus, the collection container 71 may be positioned downstream of the additional conveyor belt.

[0085] In another embodiment, the parisons 2 are inspected at the exit of the conveyor 6; in this embodiment, the apparatus 1 comprises a chute 64 downstream of the infeed belt 63. The chute 64 is inclined so that the parisons 2 can slide down it by gravity, from a first end (at the infeed belt 63) to a second end, located at a vertical height lower than the first end. In this embodiment, the inspection zone 10 and the additional inspection zone 100 are defined along the chute 64. More specifically, the light source 31 (together with the emission-polarizing filter 32) is mounted under the chute 64, while the detector 4 is mounted above the chute 64, at the light source 31. Similarly, the additional light source 310 is positioned under the chute 64 and the additional camera 410 is positioned above the chute 64 at the additional light source 310. At the second end of the chute 64, the apparatus 1 comprises an additional conveyor belt 65 to receive the parisons 2 as they leave the chute. The additional conveyor belt 65 may, for example, be in the form of a Z type conveyor; the additional conveyor belt receives the parisons 2 from a first end and transports them to a second end. Preferably, the second end is positioned at a height above the first end. A collection container may be positioned at the second end. It should be noted that a collection container may be positioned directly in place of the additional belt 65 to receive the parisons 2 that drop off the chute 64.

[0086] In another embodiment, the apparatus 1 comprises a container (or drawer) 8, configured to receive the plurality of parisons 2. Each object 8 has an at least partly transparent bottom wall 81. In this embodiment, the parisons 2 are inspected when they are inside the container 8. In effect, the apparatus 1 may comprise an operating position (or station) for the container 8. This operating position may be defined, for example, by a workbench on which to rest the container 8. At that operating position, the illuminator 3 (that is, the light source 31 and the emission-polarizing filter 32) is located under the bottom wall 81 of the container 8 to illuminate the parisons 2 contained therein through the at least partly transparent bottom wall 81. It should be noted that, in an embodiment not illustrated, the emission-polarizing filter 32 is integrated in the bottom wall 81 of the container 8. The light source 31 may also be integrated in the bottom wall 81 of the container; in this case, at the operating position, the bottom wall is preferably connected to an electric power supply to power the light source 31.

[0087] The detector 4 (that is, the camera 41 and the emission-polarizing filter 32) is located above the bottom wall 81 of the container 8 to capture images of the plurality of parisons 2. It should be noted that, in an embodiment, the detector 4 might be positioned under the bottom wall 81, and the illuminator 3, above it. The bottom wall 81 might be smooth or, on an inside face of it (on which the parisons 2 rest) it might have elongate features or grooves, configured to urge the parisons 2 to be oriented along certain directions (the orientating action could be facilitated by shaking the container 8). In the latter case, the parisons 2 are received in the container 8 in unordered fashion but are subsequently (at least partly) ordered.

[0088] The container 8 may be positioned also at an additional operating position, where the parisons 2 are interposed between the additional light source 310 and the additional camera 410.

[0089] The following paragraphs, listed in alphanumeric order for reference, are non-limiting example modes of describing this invention. [0090] A0. An apparatus 1 for the inspection of parisons 2 comprising: [0091] an inspection zone 10, configured to receive a plurality of parisons 2; [0092] an illuminator 3 including a light source 31 configured to emit a beam of light directed at the plurality of parisons 2 located in the inspection zone 10; [0093] a detector 4 comprising a camera 41 configured to capture an image of the plurality of parisons 2, located in the inspection zone 10, wherein the inspection zone is interposed between the illuminator 3 and the detector 4; [0094] a control unit 5 configured to process the image captured by the camera 41 to derive a diagnostic information regarding the defectiveness of one or more parisons 2 of the plurality of parisons 2. [0095] A. The apparatus according to paragraph A0, wherein the parisons 2 in the inspection zone are unordered (that is, each parison has its own orientation, which may be different from one parison to another). Preferably, the parisons are received directly from an injection moulding machine that makes parisons. [0096] A1. The apparatus according to paragraph A0 or A, wherein the illuminator 3 includes an emission-polarizing filter 32, configured to intercept the light beam emitted by the light source 31 and to generate a polarized light beam. [0097] A1.1. The apparatus according to paragraph A1, wherein the plurality of parisons 2 in the inspection zone 10 is operatively interposed between the emission-polarizing filter 32 and the detector 4. [0098] A1.2. The apparatus according to paragraph A1 or A1.1, wherein the emission-polarizing filter 32 is a circular polarizing filter. [0099] A2. The apparatus according to any one of paragraphs from A to A1.1, wherein the detector 4 includes a receiving polarizing filter 42. [0100] A2.1. The apparatus according to paragraph A2, wherein the plurality of parisons 2, in the inspection zone 10 is operatively interposed between the illuminator 3 and the receiving polarizing filter 42. [0101] A2.2. The apparatus according to paragraph A2 or A2.1, wherein the receiving polarizing filter 42 includes at least one a linear polarizing filter portion. [0102] A2.2.1. The apparatus according to paragraph A2.2, wherein the receiving polarizing filter 42 includes a first linear polarizing filter portion 421, having a first polarizing direction D1 and a second linear polarizing filter portion 422, having a second polarizing direction D2, different from the first polarizing direction D1. [0103] A2.2.1.1. The apparatus according to paragraph A2.2.1, wherein the receiving-polarizing filter 42 includes a plurality of units 420 and, for each unit 420, a respective plurality of linear polarizing filter portions 421, 422, 423, 424, each having a respective polarizing direction D1, D2, D3, D4 which is different from the others. [0104] A2.2.1.1.1. The apparatus according to paragraph A2.2.1 or A2.2.1.1, wherein the receiving-polarizing filter 42 includes (preferably for each unit 420 of the plurality of units), four linear polarizing filter portions 421, 422, 423, 424, having respective polarizing directions D1, D2, D3, D4 angularly spaced at 45° from each other. [0105] A3. The apparatus according to any one of paragraphs from A0 to A2.2.1.1.1, wherein the image captured by the camera 41 depicts the plurality of parisons 2, and wherein the control unit 5 is configured to derive, from the captured image, a plurality of derived images, each representing a respective parison 2 of the plurality of parisons 2 and to process each derived image of the plurality of derived images in order to generate the diagnostic information. [0106] A4. The apparatus according to any one of paragraphs from A0 to A3, comprising a conveyor 6, configured to receive the parisons 2 of the plurality of parisons 2 and to convey them to the inspection zone 10. [0107] A4.1. The apparatus according to paragraph A4, wherein the inspection zone 10 is defined along the conveyor 6. [0108] A4.1.1. The apparatus according to paragraph A4.1, wherein the conveyor 6 includes an at least partly transparent surface configured to supportably receive the plurality of parisons 2. [0109] A4.2. The apparatus according to any one of paragraphs from A4 to A4.1.1, wherein the conveyor 6 includes a carousel 61. [0110] A4.2.1. The apparatus according to paragraph A4.2, wherein the carousel 61 includes an at least partly transparent plate for supportably receiving the parisons. [0111] A4.2.1.1. The apparatus according to paragraph A4.2.1, wherein the at least partly transparent plate is interposed between the illuminator and the detector. [0112] A4.2.1.2. The apparatus according to paragraph A4.2.1 or A4.2.1.1, wherein the illuminator and the detector are at a fixed position relative to the carousel which rotates. [0113] A4.2.1.3. The apparatus according to any one of paragraphs from A4.2.1 to A4.2.1.2, wherein the illuminator is mounted under the carousel and the detector is mounted above the carousel, along a vertical direction (parallel to the weight force). [0114] A4.2.2. The apparatus according to any one of paragraphs from A4.2 to A4.2.1.3, wherein the carousel 61 includes a rotary frame 612 and a plurality of at least partly transparent plates 611 mounted on the frame 612. [0115] A4.2. The apparatus according to any one of paragraphs from A4 to A4.2.2, comprising a collection container 71. [0116] A4.2.1. The apparatus according to paragraph A4.2, wherein the conveyor 6 is configured to convey the plurality of parisons to the collection container 71. [0117] A4.2.1.1. The apparatus according to paragraph A4.2.1, wherein the camera 41 is configured to capture images of the parisons 2 of the plurality of parisons 2 as soon as they are released from the conveyor 6, so the inspection zone 10 is defined between the conveyor 6 and the collection container 71. [0118] A5. The apparatus according to any one of paragraphs from A0 to A3, comprising a container 8 having an at least partly transparent bottom 81, configured to receive the plurality of parisons 2, wherein the container 8 is positionable at an operating position between the detector 4 and the illuminator 3. [0119] A5.1. The apparatus according to paragraph A5, wherein, at the operating position of the container 8, the plurality of parisons 2 is operatively interposed between the emission-polarizing filter 32 and the receiving polarizing filter 42. [0120] A6. The apparatus according to any one of paragraphs from A0 to A5.1, comprising: [0121] an additional inspection zone 100, configured to receive the (unordered) plurality of parisons 2, upstream or downstream of the inspection zone 10; [0122] an additional light source 310 configured to emit a beam of light directed at the plurality of parisons 2 located in the additional inspection zone 100; [0123] an additional camera 410, configured to capture an additional image of the plurality of parisons 2 located in the additional inspection zone 100, wherein the plurality of parisons 2 in the additional inspection zone 100 is operatively positioned between the additional light source 310 and the additional camera 410. [0124] A6.1. The apparatus according to paragraph A6, wherein the control unit 5 (or an additional control unit) is configured to process the additional image captured by the additional camera 410 to derive a diagnostic information regarding a colour quality of the one or more parisons. [0125] B0. A method for the inspection of parisons 2, comprising the following steps: [0126] receiving a plurality of parisons in an inspection zone; [0127] illuminating the parisons of the plurality of parisons through a light source; [0128] capturing an image of the plurality of illuminated parisons in the inspection zone; [0129] processing the image captured by the camera to derive a diagnostic information regarding the defectiveness of one or more parisons of the plurality of parisons. [0130] B. The method according to paragraph B0, wherein an unordered flow of parisons is received (in the inspection zone); that is to say, the parisons received in the inspection station are not ordered (or singulated). [0131] B1. The method according to paragraph B0 or B, wherein the parisons in the inspection zone are illuminated with a beam of polarized light. [0132] B1.1. The method according to paragraph B1, wherein illuminating includes generating a non-polarized light beam through a light source 31 and intercepting the light beam on an emission-polarizing filter 32, interposed between the light source 31 and the plurality of parisons, to generate the polarized light beam. [0133] B1.1.1. The method according to paragraph B1.1, wherein the emission-polarizing filter 32 is a circular polarizing filter. [0134] B1.2. The method according to paragraph B1 or B1.1, comprising a step of receiving the beam of polarized light on a receiving polarizing filter 42, interposed between the parisons 2 and the camera. [0135] B1.2.1. The method according to paragraph B1.2, wherein the plurality of parisons 2 in the inspection zone 10 is operatively interposed between the emission-polarizing filter 32 and the receiving polarizing filter. [0136] B1.2.2. The method according to paragraph B1.2 or B1.2.1, wherein the receiving-polarizing filter 42 includes a plurality of linear polarizing filter portions 421, 422, 423, 424, each having a respective polarizing direction D1, D2, D3, D4 which is different from the others (preferably, four portions with polarizing directions angularly spaced at 45° from each other). [0137] B1.2.3. The method according to paragraph B1.2 or B1.2.1 or B1.2.2, wherein the receiving-polarizing filter 42 includes a plurality of units 420 and, for each unit, a respective plurality of linear polarizing filter portions 421, 422, 423, 424, each having a respective polarizing direction D1, D2, D3, D4 which is different from the others (preferably, four portions with polarizing directions angularly spaced at 45° from each other). [0138] B2. The method according to any of paragraphs from B0 to B1.2.2, comprising a step of transporting the plurality of parisons 2 on a conveyor 6. [0139] B2.1. The method according to paragraph B2, wherein the parisons 2 are inspected while they are being transported by the conveyor 6. [0140] B2.1.1. The method according to paragraph B2.1, wherein, during inspection, the parisons 2 are transported along a curved path at a constant height. [0141] B2.1.2. The method according to paragraph B2.1 or B2.1.1, wherein the conveyor 6 includes an at least partly transparent surface configured to supportably receive the plurality of parisons 2. [0142] B2.2. The method according to any one of paragraphs from B2 to B2.1.2, wherein the conveyor 6 includes a carousel 61. [0143] B2.2.1. The method according to paragraph B2.2, wherein the carousel 61 includes an at least partly transparent plate for supportably receiving the parisons. [0144] B2.2.1.1. The method according to paragraph B2.2.1, wherein the at least partly transparent plate is interposed between the illuminator and the detector. [0145] B2.2.1.2. The method according to paragraph B2.2.1 or B2.2.1.1, wherein the illuminator and the detector are at a fixed position relative to the carousel which rotates. [0146] B2.2.1.3. The method according to any one of paragraphs from B2.2 to B.2.2.1.2, wherein the illuminator is mounted under the carousel and the detector is mounted above the carousel, along a vertical direction (parallel to the weight force). [0147] B2.3. The method according to any one of paragraphs from B2 to B2.1.2, wherein the conveyor 6 transports the parisons upwards. [0148] B2.3.1. The method according to paragraph B2.3, wherein the conveyor includes a plurality of abutment members (preferably transparent) to intercept the parisons and to orient them in a predetermined direction while they move. [0149] B2.3.2. The method according to paragraph B2.3 or B2.3.1, wherein the parisons, while they are being transported upwards, are illuminated with polarized light (with linear or circular polarization). [0150] B2.3.2.1. The method according to paragraph B2.3.2, wherein the parisons, while they are being transported upwards, are illuminated with non-polarized light in an additional inspection zone (to detect colour defects). [0151] B2.4. The method according to any one of paragraphs from B2 to B2.3, wherein the conveyor 6 conveys the plurality of parisons into the collection container 71. [0152] B2.4.1. The method according to paragraph B2.4, wherein the camera 41 captures images of the parisons 2 of the plurality of parisons 2 as soon as they are released from the conveyor 6, so the inspection zone 10 is defined between the conveyor 6 and the collection container 71. [0153] B3. The method according to any one of paragraphs from B0 to B1.2.2, comprising a container 8 having an at least partly transparent bottom 81, configured to receive the plurality of parisons 2, wherein the parisons are inspected while they are inside the container 8 and the container 8 is positioned at an operating position between the detector 4 and the illuminator 3. [0154] B3.1. The method according to paragraph B3, wherein, at the operating position of the container 8, the plurality of parisons 2 is operatively interposed between the emission-polarizing filter 32 and the receiving polarizing filter 42. [0155] B4. The method according to any one of paragraphs from B0 to B3.1, further comprising the following steps: [0156] receiving the plurality of parisons in an additional inspection zone; [0157] illuminating the parisons located in the additional inspection zone with an additional light source; [0158] capturing an additional image of the plurality of illuminated parisons in the additional inspection zone, wherein the additional image is captured by an additional camera; [0159] processing the additional image captured by the additional camera to derive a diagnostic information regarding a colour quality of the one or more parisons of the plurality. [0160] C0. A use of illumination with polarized light to inspect an unordered flow of parisons 2. [0161] C. The use according to paragraph C0, wherein the unordered flow of parisons is at the exit from a machine for forming parisons by injection moulding. [0162] C1. The use according to paragraph C0 or C, wherein the parisons in the unordered flow of parisons 2 have a random orientation. [0163] C1.1. The use according to any one of paragraphs from C0 to C1, wherein the light has circular polarization. [0164] C2. The use according to any one of paragraphs from C0 to C1.1, wherein, during inspection, the parisons move under the effect of gravity. [0165] C2.1. The use according to paragraph C2, wherein, during inspection, the parisons slide down a chute (which is preferably at least partly transparent. [0166] C3. The use according to any one of paragraphs from C0 to C1.1, wherein, during inspection, the parisons are transported by a conveyor (preferably along an at least partly circular path). [0167] C3.1. The use according to paragraph C3, wherein, during inspection, the parisons are transported by a carousel 61. [0168] C4. The use according to paragraph C0 or C, wherein the light has linear polarization and wherein the parisons in the unordered flow of parisons 2 have a predetermined orientation. [0169] C4.1. The use according to paragraph C4, wherein, during inspection, the parisons are transported upwards.