Apparatus and method for inspecting transparent cylindrical containers containing milky products, in particular for medical applications
Patent Information
- Application Number
- JP2021196834
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2020-12-09
- Filing Date
- 2021-12-03
- Publication Date
- 2025-08-15
- Estimated Expiration
- 2041-12-03
AI Technical Summary
Existing optical systems for inspecting transparent containers of pharmaceutical substances struggle to reliably distinguish between internal and external contaminants, leading to high false rejection rates and increased inspection times.
A device and method using a video camera and dual lighting system to alternately illuminate a transparent cylindrical container at regular angular intervals during rotation, capturing and combining partial images to differentiate between contaminants on the inner and outer surfaces by analyzing chromatic aberrations in combined images.
Accurately distinguishes between internal and external contaminants, reducing false rejections and significantly decreasing inspection time while maintaining high detection accuracy.
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention relates to an apparatus and a method for inspecting a transparent cylindrical container containing a milky white product, particularly for medical use.
Background Art
[0002] As is well known, in the medical field, it is essential to analyze transparent containers of pharmaceutical substances in order to detect the presence of any impurities inside the container. In the case of a positive result, since it is not acceptable for the pharmaceutical substance to contain certain contaminants, the container will clearly have to be discarded.
[0003] The systems used in the art are optical and utilize a video camera to scan each container in order to detect any contaminants. However, the known systems have several drawbacks.
[0004] In fact, the known optical systems can detect the presence of contaminants / impurities, but they cannot reliably distinguish whether the position of the contaminants is inside or outside the container with respect to the container. In this case, clearly, the container has to be discarded if the contaminants are inside, i.e., in contact with the pharmaceutical substance contained therein.
[0005] Clearly, for safety reasons, the known systems are calibrated to be "conservative", resulting in a high rate of positive rejections. To improve at least part of this drawback, the inspection time of the container is extended, but in this way, while on the one hand false rejections are reduced, on the other hand, the inspection time and cost increase in an unacceptable manner.
[0006] Since the batch to be inspected can contain tens of thousands of containers, the inspection time should be regarded as a non-negligible cost factor.
[0007] Therefore, known solutions do not allow for the simultaneous achievement of a low rate of positive failures and reduced inspection time. [Overview of the Initiative]
[0008] Therefore, there is a need to address the shortcomings and limitations mentioned by reference to the prior art.
[0009] This requirement is met by the apparatus for inspecting transparent cylindrical containers containing milky white products, particularly for medical use, as described in claim 1, and by the method described in claim 6. [Brief explanation of the drawing]
[0010] Further features and advantages of the present invention will become more apparent from the following description, including preferred and non-limiting embodiments, among: [Figure 1] Figures 1a-1b and 2a-2b show schematic top views of an apparatus for inspecting a transparent cylindrical container containing a milky white product according to an embodiment of the present invention; [Figure 2] Figures 1a-1b and 2a-2b show schematic top views of an apparatus for inspecting a transparent cylindrical container containing a milky white product according to an embodiment of the present invention; [Figure 3a] Figure 3a shows a schematic view from above of the inspection apparatus according to the present invention in a continuous inspection process; [Figure 3b] Figure 3b shows a growth diagram of the image of the outer surface of the container obtained following the corresponding inspection step in Figure 3a; [Figure 4] Figures 4a, 4b, 4c, and 4d show schematic diagrams of the processing of images captured by the inspection apparatus according to the present invention; [Figure 5] Figure 5 shows a graphical representation of the identification of external contaminants in a container analyzed according to the apparatus and inspection method of the present invention; [Figure 6] Figure 6 shows a graphical representation of the identification of contaminants inside a container analyzed according to the apparatus and inspection method of the present invention.
[0011] Elements or parts of elements common to the embodiments described hereafter are indicated by the same numerical reference. [Modes for carrying out the invention]
[0012] Referring to the above figure, 4 is used to comprehensively illustrate an apparatus for inspecting a transparent cylindrical container 8 containing a milky white product, particularly for medical use.
[0013] It should be noted that the cylindrical container 8 is transparent in order to allow the substance contained therein, preferably a milky white substance, to be visible from the outside. It should be noted that the “milky white liquid” is a solution having high turbidity. Turbidity (measured with a turbidimeter) is the ratio of the intensity of light diffused by the solution in a direction perpendicular to the direction of the incident light ray to the intensity of the light ray itself. Turbidity can also be defined in relation to light transmittance, i.e., as the ratio of the intensity of light traveling in the same direction as the incident light to the intensity of the incident light (measured with a turbidimeter).
[0014] Therefore, the cylindrical container 8 is preferably made of glass or plastic, such as plexiglass.
[0015] Furthermore, the cylindrical container 8 has an axis of axial symmetry XX; in other words, they are rotational solids about the axis of axial symmetry XX.
[0016] The inspection device 4 includes a support and / or gripping device (not shown) for the cylindrical container 8, provided together with motor means for rotating the cylindrical container 8 about a vertical rotation axis YY, which is adapted to support the cylindrical container 8 and coincides with the axis of cylindrical symmetry xx of the cylindrical container 8.
[0017] For the purposes of this invention, it is possible to use a plurality of supports and / or gripping devices for the cylindrical container 8; care must be taken to ensure that the supports and / or gripping devices do not obstruct the field of view and therefore the identification of any impurities on the cylindrical container 8. For this purpose, supports and gripping devices that grip the container by a support base of the container or otherwise pull the container into rotation are preferred. There are numerous gripping devices / means suitable for the above purpose. For example, it is possible to grip the bottom-to-top of the bottle or to use a clamp on the neck of the bottle, etc. The important thing is that these devices rotate the bottle around its main axis.
[0018] Apparatus 4 further includes a video camera 12 directed to capture an image of the window 16 in the side wall 20 of the cylindrical container 8 in the form of pixels, framing and capturing it. Obviously, the fact that the cylindrical container 8 is transparent allows the video camera 12 to capture not only an image of the side wall 20 of the cylindrical container 8, but also an image of its contents (preferably a milky white liquid). In fact, the object of the present invention is to detect the presence of impurities and to distinguish whether such possible impurities are on the outside, i.e., on the outer surface 22 of the side wall 20, or on the inside, i.e., on the inner surface 23 of the side wall 20 of the cylindrical container 8. If the impurities are on the inner surface 23, they will be in direct contact with the liquid contained in the cylindrical container 8, which will need to be discarded.
[0019] Apparatus 4 further includes a first lighting device 24 collimated and directed to illuminate the window 16, and a second lighting device 28 collimated and directed to illuminate the window 16.
[0020] The second lighting device 28 is positioned symmetrically with respect to the window 16, and opposite to the first lighting device 24.
[0021] Device 4 is operably connected to the support and / or grip device, the video camera 12, and the first and second lighting devices 24, 28.
[0022] - Until a complete 360° rotation of the cylindrical container is performed, for each angular interval, while alternately activating the first lighting device 24 and the second lighting device 28, the control device 32 is programmed to capture the first and second partial images 36', 36'' (FIGS. 3a - 3b) of the window 16 at a constant angular interval. In particular, the video camera 12 captures the first partial image 36' during the activation of the first lighting device 24 and the second partial image 36'' during the activation of the second lighting device 28.
[0023] Thus, the control device 32 is programmed to combine, without interruption, the individual partial images 36', 36'' obtained by alternately activating the first lighting device 24 to obtain a first set of images 40' of the cylindrical container 8 and the second lighting device 28 to obtain a second set of images 40'' of the cylindrical container 8 (FIGS. 4c - 4d).
[0024] Thus, the control device proceeds with the step of identifying the presence of any irregular pixels 48 having a chromatic aberration corresponding to contaminants within each set of images.
[0025] In the case where at least one of the irregular pixels 48 is identified, a control image 52 is created from the difference between the first set of images 40' and the second set of images 40'', and the position of the contaminants with respect to the side wall 20 of the cylindrical container 8 is classified according to the control image 52.
[0026] In particular, for the purpose of identifying the position, according to a possible embodiment, the control device 32 is programmed as follows:
[0027] - If the control image 52 includes at least one irregular pixel 48, classify the contaminants as being outside the side wall 20 of the cylindrical container 8 (FIG. 5),
[0028] -If the control image 52 does not contain at least one irregular pixel 48, the contaminant is classified as being inside the side wall 20 of the cylindrical container 8 (Figure 6).
[0029] Clearly, if it is determined that the contaminant is located inside the cylindrical container 8, the container will be discarded.
[0030] To ensure proper detection and classification of contaminants, accurate shots of the window 16 must be taken by alternately activating the first and second lighting devices 24 and 28.
[0031] For this purpose, according to a possible embodiment, the support and / or grip device is provided together with a rotary encoder for measuring the rotation of the cylindrical container 8; preferably the rotary encoder is operablely connected to a control device 32 for alternately activating the first and second lighting devices 24, 28.
[0032] The angular interval at which the linear video camera scans the extension of the container depends on the resolution desired to be applied in the direction of the container's extension. The values for these angular ranges may be, for example, 0.044 degrees, obtained by dividing the 360° rotation angle of the container by an 8192 encoder pulse (360° / 8192).
[0033] A constant angular interval is, therefore, an angular interval of 0.05 in sexagesimal degrees, as an example.
[0034] In a possible embodiment, in order to avoid a reduction in resolution, the images of the side wall 20 and, in particular, the window 16 of the cylindrical container 8 are oversampled by a factor of 2, with the resolution doubled in the direction of extension of the side: in this way, two final images with accurate resolution are obtained.
[0035] The operation of the inspection apparatus according to the present invention will be explained.
[0036] In particular, the principle on which the present invention is based starts from the hypothesis that, considering its distance from the liquid equal to the thickness of the (transparent) side wall of the container 8, a contaminant adhering to the outer surface 22 of the side wall 20 will cast a shadow on the milky liquid when illuminated by collimated and non-perpendicular incident light (Figure 1a-1b). On the other hand, an object or contaminant adhering to the inner surface 23 of the cylindrical container 8 will be in contact with the liquid, and as a result, the structure will not cast any shadow on the liquid in which the contaminant is in direct contact (Figure 2a-2b).
[0037] By detecting the projected shadow of the contaminant, it is possible to determine whether the contaminant is inside or outside the cylindrical container 8. The problem, therefore, is to distinguish the shadow of the object from a thin, sparse layer of contaminant. For this reason, three-dimensional lighting was introduced into the process.
[0038] When an object on the outer surface 22 of the cylindrical container 8 is illuminated by two collimated lights, namely the first lighting device 24 and the second lighting device 28, whose light cuts across the outer surface 22 at a symmetrical angle, it will cast two shadows in opposite directions, symmetrical with respect to its position.
[0039] While the cylindrical container 8 is rotating (Figures 3a-3b), the video camera 12 captures lines at constant angular intervals dθ, for example, by using a rotary encoder connected to a motor that sets the cylindrical container 8 to rotate. In this way, the video camera 12 produces a continuous extension of the side surface 20 of the cylindrical container 8.
[0040] When acquiring lines, the first and second symmetrical lighting devices 24 and 28 are activated alternately. The first lighting device 24 is activated only when the second lighting device 28 is off and when acquiring even-numbered lines. The sum of the even-numbered lines, i.e., the sum of the first partial images 36' captured while the first lighting device 24 is activated, constitutes the first aggregate image 40' (Figures 4a-4d).
[0041] The first aggregate image 40' is therefore an extension of the entire side wall 20 of the cylindrical container 8 obtained by activating only the first lighting device 24.
[0042] Conversely, the second lighting device 28 is only activated during the acquisition of odd-numbered wires, while the first lighting device 24 remains off, and only during the acquisition of odd-numbered wires.
[0043] The sum of the odd-numbered lines, i.e., the sum of the second partial images 36'' taken during the activation of the second lighting device 28, constitutes the second aggregate image 40'' (Figures 4a-4d).
[0044] The first aggregate image 40'' is therefore an extension of the entire side wall 20 of the cylindrical container 8 obtained by activating only the first lighting device 28.
[0045] The first composite image 40' and the second composite image 40'' will have many lines, which is half the number of lines for all the captured images.
[0046] As shown, in order to avoid a reduction in resolution, the captured image is oversampled by a factor of 2, with the resolution doubled in the direction extending along the side wall 20. In this way, two final images with accurate resolution are obtained.
[0047] In this regard, the so-called control image 52 is calculated as the difference between the first aggregate image 40' and the second aggregate image 40'', and only the irregular pixels 48, i.e., pixels whose grayscale has changed, are highlighted. This is simply due to the shadows that arise at the differences in the first aggregate image 40' relative to the second aggregate image 40''. If contaminants are present, they will not appear in different positions, but only their shadows will change. We can therefore see that, in the presence of the aforementioned differences, the objects that generate them will be external and contained between the two shadows (Figure 5). The objects will also be at a precise distance from them, proportional to the thickness of the side wall 20 of the cylindrical container 8 and the angle of incident light. These objects will ultimately be excluded from the contaminants that are considered to be internal to the bottle.
[0048] As can be understood from the explanation above, the apparatus and inspection method according to the present invention make it possible to overcome the shortcomings shown in the prior art.
[0049] In particular, the present invention enables the detection of contaminants present inside a container (which are not acceptable for testing purposes) in distinction from contaminants present outside the container (which are considered acceptable instead).
[0050] This indicates a dramatic decrease in false failures, as they are found on the outside of the container and therefore do not come into contact with the pharmaceutical product, due to the detection of dirt, fibers, and other objects.
[0051] The "spin and stop" approach, typical for particle analysis of clear, water-like products, is impractical because it does not allow for centrifugation and keeps contaminants on the outer wall where they would otherwise be invisible, even if they have moved tens of millimeters from the wall. A cosmetic approach, i.e., one involving continuous rotation and acquisition of rotational images, makes it possible to detect contained contaminants.
[0052] This method makes it possible to distinguish between the external and internal location of contaminants, allowing for the analysis of containers containing milky liquids using a superficial approach, dramatically reducing false rejections due to external contamination.
[0053] A person skilled in the art could make numerous modifications and alterations to the above apparatus and inspection method to satisfy specific, conditional requirements, all of which, however, fall within the scope of the invention as defined by the subsequent claims.
Claims
1. a support and / or gripping device for the cylindrical container (8), suitable for supporting the cylindrical container (8) and provided with means for rotating the cylindrical container (8) about a vertical axis of rotation (Y-Y), coinciding with the axis of cylindrical symmetry (X-X) of said cylindrical container (8); a video camera (12) aimed to frame and take an image, in the form of pixels, of the window (16) in the side wall (20) of said cylindrical container (8); a first collimated lighting device (24) directed to illuminate said window (16); a second lighting device (28) positioned symmetrically to the first lighting device (24) with respect to the optical axis of the video camera (12) and collimated and directed to illuminate the window (16); - electrically and / or signally connected to said support and / or gripping device, said video camera (12) and said first and second lighting devices (24, 28), - taking first and second partial images (36', 36'') of the window (16) at regular angular intervals, while activating the first and second lighting devices (24, 28) alternately for each angular interval, until a complete rotation of 360° of the cylindrical container (8) has been performed; - combining, without interruption, first and second partial images (36', 36'') obtained by alternately activating a first lighting device (24) to obtain a first aggregate image (40') of said cylindrical container (8) and a second lighting device (28) to obtain a second aggregate image (40'') of said cylindrical container (8); - identifying in each aggregate image (40', 40'') the presence of possible irregular pixels (48) having color differences corresponding to contaminants; a control device (32) programmed to, in case of identification of at least one of said irregular pixels (48), realize a control image (52) obtained from the difference between said first and second set images (40', 40'') and to categorize, according to said control image (52), whether a contaminant is located outside or inside said cylindrical container (8); When a time interval between alternate activations of the first lighting device (24) and the second lighting device (28) is Δt and an angular velocity of rotation of the cylindrical container (8) is ω, the values of Δt and ω during the photographing are selected so that an image of the contaminant and its shadow can be included in both the first set of images (40') and the second set of images (40''). Apparatus (4) for inspecting a transparent cylindrical container (8) containing a milky white product.
2. The control device (32): - classifying the contaminant as being external to the side wall (20) of the cylindrical container (8) if the control image (52) contains at least one irregular pixel (48); - The device (4) of claim 1, programmed to classify a contaminant as being internal to the side wall (20) of the cylindrical container (8) if the control image (52) does not contain at least one irregular pixel (48).
3. 3. The device (4) of claim 1 or 2, wherein the support and / or gripping device is provided with a rotary encoder for measuring the rotation of the cylindrical container (8), the rotary encoder being operatively connected to the control device (32) for alternately activating the first lighting device (24) and the second lighting device (28).
4. 4. The apparatus (4) according to claim 1, 2 or 3, wherein, in order to avoid a reduction in resolution, images of the side wall (20) of the cylindrical container (8) are acquired twice in total, before and after rotating the cylindrical container (8) through the fixed angular interval.
5. 5. The apparatus (4) of claim 1, 2, 3, or 4, wherein the regular angular intervals are 0.044 degrees.
6. - providing a transparent cylindrical container (8) containing a milky white product, supported for rotation about a vertical axis of rotation (Y-Y) coinciding with the axis of axial symmetry (X-X) of said container (8) itself; - providing a video camera (12) aimed to frame and take an image, in the form of pixels, of the window (16) in the side wall (20) of said cylindrical container (8); - providing a first collimated lighting device (24) directed to illuminate said window (16); - providing a second lighting device (28) positioned symmetrically to the first lighting device (24) with respect to the optical axis of the video camera (12) and collimated and aimed to illuminate the window (16); - taking first and second partial images (36', 36'') of the window (16) at regular angular intervals, while for each angular interval alternately activating the first and second lighting devices (24, 28) until a complete rotation of 360° of the cylindrical container (8) has been performed; - combining, without interruption, the individual partial images (36', 36'') obtained by alternately activating a first lighting device (24) to obtain a first collective image (40') of said cylindrical container (8) and a second lighting device (28) to obtain a second collective image (40'') of said cylindrical container (8); - identifying, in each aggregate image (40', 40''), the presence of possible irregular pixels (48) having color differences corresponding to contaminants; - in case of identification of at least one of said irregular pixels (48), realizing a control image (52) obtained from the difference between said first set image (40') and said second set image (40'') and classifying, according to said control image (52), whether a contaminant is located outside or inside said cylindrical container (8); Including, When a time interval between alternate activations of the first lighting device (24) and the second lighting device (28) is Δt and an angular velocity of rotation of the cylindrical container (8) is ω, the values of Δt and ω during the photographing are selected so that an image of the contaminant and its shadow can be included in both the first set of images (40') and the second set of images (40''). A method for inspecting a transparent cylindrical container (8) containing a milky white product.
7. - classifying the contaminant as being external to the side wall (20) of the cylindrical container (8) if the control image (52) contains at least one irregular pixel (48); - classifying the contaminants as being internal to the side wall (20) of the cylindrical container (8) if the control image (52) does not contain irregular pixels (48). The method of claim 6, comprising:
8. 8. The method according to claim 6 or 7, further comprising the step of acquiring images of the side wall (20) of the cylindrical container (8) twice, once before and once after rotating the cylindrical container (8) through the fixed angular interval.
9. 9. The method of claim 6, 7, or 8, wherein the regular angular intervals are 0.044 degree angular intervals.