Method and device for inspecting an incision on a plastic cap
View Patent ↗A method for inspecting an incision made on a lateral surface of a plastic cap includes the following steps: conveying the plastic cap along an inspection path through an inspection zone in which the cap is inspected; emitting a polarized light collimated along a light orientation towards the inspection zone; capturing image data representing at least one image of the lateral surface of the cap through an optical sensor; receiving the image data in a control unit; processing the image data to derive information about the incision.
1 . A method for inspecting an incision made on a lateral surface of a plastic cap, the method comprising the following steps:
conveying the plastic cap on a conveyor along an inspection path through an inspection zone in which the cap is inspected;
emitting a light along an emission orientation, the light being collimated along a light orientation towards the inspection zone, through an illuminator, the illuminator including a light source for emitting a beam of light, to illuminate the lateral surface of the cap;
rotating the cap about an axis of rotation, so that the cap rotates about its axis of symmetry;
capturing image data representing at least one image of the lateral surface of the cap through an optical sensor;
deflecting the beam light from the emission orientation to the light orientation by a reflective element interposed between the cap and the optical sensor, along a detection direction of the optical sensor, wherein the reflective element allows illumination of the lateral surface and acquisition of the lateral surface from the same side, so to capture the lateral surface of the cap in reflection,
processing the image data to derive information about the incision based on the image data,
wherein the step of rotating exposes different portions of the lateral surface of the cap to the optical sensor, to allow the optical sensor to capture an image of each portion of the lateral surface of the cap.
2 . The method according to claim 1 , wherein the image data represent a plurality of images of the lateral surface of the cap, corresponding to respective portions of the lateral surface of the cap, spaced from each other along the lateral surface.
3 . The method according to claim 2 , wherein the step of processing the image data produces a developed image depicting the lateral surface of the cap represented in a plane.
4 . The method according to claim 1 , comprising a step of holding by suction, in which the cap being conveyed along the inspection path is held down on the conveyor by suction.
5 . The method according to claim 1 , comprising a step of rotating, in which the cap is rotated about an axis of rotation which is perpendicular to the inspection path, so the cap rotates about its axis of symmetry.
6 . The method according to claim 1 , wherein the plastic cap comprises a first portion and a second portion, connected to the first portion by frangible connecting means removable to open the cap and/or by a permanent connector which allows relative movement between the first portion and the second portion of the cap.
7 . The method according to claim 1 , comprising an additional step of imaging to form a plurality of steps of imaging, each intended to capture a corresponding subset of image data, each representing images of a corresponding portion of the lateral surface of the cap.
8 . The method according to claim 1 , wherein the emitted light is polarized.
9 . The method according to claim 1 , wherein the illuminator is located outside the cap and the optical sensor detects light rays reflected by the illuminated the lateral surface of the cap.
10 . A device for inspecting an incision made on a lateral surface of a plastic cap, the device comprising:
an inspection zone in which the cap to be inspected can be positioned;
a conveyor, configured to convey the cap along an inspection path passing through the inspection zone;
an illuminator, including a light source configured to emit a beam of light along an emission orientation, the light being collimated along a light orientation towards the inspection zone, to illuminate the lateral surface of the cap;
an optical sensor configured to capture image data representing at least one image of the lateral surface of the cap;
a reflective element, interposed between the cap and the optical sensor along a detection direction of the optical sensor and configured for deflecting the beam light from the emission orientation to the light orientation, so to allow illumination of the lateral surface and acquisition of the lateral surface from the same side, so to capture the lateral surface of the cap in reflection;
a control unit, configured to receive the image data and to process the image data to derive information about the incision from the image data,
wherein the cap is configured for rotating about an axis of rotation, so that the cap rotates about its axis of symmetry, in order to expose different portions of the lateral surface of the cap to the optical sensor to allow the optical sensor to capture an image of each portion of the lateral surface of the cap.
11 . The device according to claim 10 , wherein the image data represent a plurality of images of the lateral surface of the cap, corresponding to respective portions of the lateral surface of the cap, spaced from each other along the lateral surface.
12 . The device according to claim 11 , wherein the control unit is configured to process the image data to derive a developed image representing the lateral surface of the cap in a plane.
13 . The device according to claim 10 , wherein the conveyor comprises a hold element, configured to keep the cap in an inspection position as it moves along the inspection path.
14 . The device according to claim 13 , wherein the hold element comprises a suction unit, configured to apply a negative pressure to hold the cap in place as it is transported along the inspection path.
15 . The device according to claim 13 , wherein the hold element rotates about an axis of rotation which is perpendicular to the inspection path to rotate the cap about its axis of symmetry.
16 . The device according to claim 13 , wherein the hold element comprises a plurality of references, spaced from each other along an outer circumference of the hold element.
17 . The device according to claim 10 , comprising an additional optical sensor to form a plurality of optical sensors, disposed at respective imaging positions, spaced from each other, to capture corresponding subsets of the image data, each representing images of a corresponding portion of the lateral surface of the cap.
18 . The device according to claim 10 , wherein the inspection path defines a circular arc.
19 . The device according to claim 10 , wherein the control unit is configured to filter the image data to keep only the image data representing a predetermined portion of the image of the lateral surface.
20 . The device according to claim 10 , wherein the illuminator is configured to emit the collimated light along the emission orientation inclined to the light orientation.
21 . The device according to claim 10 , wherein the collimated light is polarized.
22 . A machine for testing a detachment force between a first portion of a cap and a second portion of a cap, connected to the first portion of the cap by one or more connectors, the machine comprising:
a gripping element configured to hold the second portion of the cap;
a pushing element, movable relative to the gripping element along a test orientation and configured to apply a force between the first portion and the second portion of the cap to move them along the test orientation in a pushing direction;
an inspecting device, wherein the inspecting device comprises:
an inspection zone in which the cap to be inspected can be positioned;
a conveyor, configured to convey the cap along an inspection path passing through the inspection zone;
an illuminator, configured to emit a light collimated along a light orientation towards the inspection zone, to illuminate the lateral surface of the cap;
an optical sensor configured to capture image data representing at least one image of the lateral surface of the cap;
a control unit, configured to receive the image data and to process the image data to derive information about the incision from the image data.
23 . The machine according to claim 22 , wherein the inspecting device is configured to generate, responsive to the image data, positioning data representing a deviation between a feed position, at which the cap is fed to the machine, and a predetermined test position, and wherein the machine comprises a positioning actuator, configured to rotate the cap from the feed position to the predetermined test position, based on the positioning data.