DE3514313A1 - METHOD AND DEVICE FOR INSPECTING AND SORTING GLASS CONTAINERS - Google Patents

Description

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The present invention relates to the inspection and sorting of transparent containers in for defects in the container side walls. More precisely, the invention relates to the Inö inspection of glass containers for refractive sidewall defects such as Bubbles and / or opaque side wall defects, such as stones, and the optional sorting out of containers provided with defects detected in this way.

Various types of defects can occur in the manufacture of glass containers. It is known, optical scanning method for the inspection of such containers for defects which the affect optical permeability properties of the container side wall, use. In U.S. Patents 4,378,493, 4,378,494, and 4,378,495, which are assigned to the present applicant; a method and a device are described, according to which glass containers by a plurality from positions or stations in which they are physically and optically inspected will. A glass container is positioned vertically at an optical inspection station held and rotated around its vertical central axis. A source of lighting sets up a diffuse one

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Light through the container side wall. A Kanera, the a variety of photosensitive elements possesses which in a linear arrangement parallel to the vertical axis of the container rotation are oriented is arranged so that they are through a vertical strip of the container side wall urgent light captured. The output signal given by each photosensitive element is detected in steps of container rotation and event signals are generated when the size of neighboring signals differs by more than a predetermined threshold value. is if this is the pail, an appropriate reject signal is generated and the defective container becomes sorted out of the conveyor series.

The methods and apparatus described in the aforementioned patents, which are generally also referred to as sidewall inspection devices, are found to be extremely effective relating to general automated inspection and sorting of glass containers. It however, some problems arise when using these devices to detect certain types of Defects are used. For example, to increase the detection capacity of refractive defects that extend transversely to the container axis, such as ribbon-like defects, was proposed in American patent application 424 687 of September 27, 1982, a filtered source of diffuse light to be directed against the side wall of the container in order to do this

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generate a longitudinal illumination intensity gradient in the direction of the vertical stripe field of view of the camera is variable and thus runs essentially parallel to the axis of the container. The light intensity is detected and there are error signals depending on differences between the intensities generated on successive photosensitive elements within the camera.

Defective containers are then sorted out from the conveyor row. This procedure was successful for the reliable and effective detection of transverse ribbon-like cracks and for Sorting out of containers that have such defects, used.

When using the sidewall inspection device described above Problems have also arisen in distinguishing types and sizes of the respective defects. For example, finds in the sidewall inspection apparatus, use a wide-width light source which is wide enough that most defects will not refract light enough to make it as a dark point on the light background of the light source. However, since opaque defects absorb light energy, they are as dark points on the light background of the Light source visible. In other words, the sidewall inspection device detects opaque Defects, but usually not refractive defects. The present invention deals with the problem of capturing

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opaque defects, while at the same time allowing the detection of refractive defects optical amplification enables. In addition, the invention enables the distinction between small refractive defects such as small bubbles in the container side wall, and large ones refractive defects such as large bubbles. In the manufacture of glass containers is It is of importance to both larger refractive defects, such as large bubbles, as well Identify opaque defects as both are starting points for the propagation of cracks which can ultimately lead to the breakage of the container. On the other hand are small refractive defects, such as small bubbles in the container side wall, are commercially acceptable, therefore such containers should not be rejected. These problems occur especially in the manufacture of narrow-necked containers such as beer bottles. That Sorting out and rejecting containers with defects that are accepted by the trade, is ineffective and increases manufacturing costs. Therefore, there is a need for an improved one Procedure for the reliable detection of defects that are unacceptable for the trade, while these defects are at the same time distinguished from commercially acceptable defects should, and for sorting out and rejecting only those containers that are not for trade have acceptable defects.

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The invention is based on the object of an improved Method and a corresponding device for the inspection and sorting of to create transparent containers, in particular glass containers, which are economical Ways can be used in the above Realize proven technology described in patents and patent applications, are able to distinguish the character and size of sidewall defects, and the vessels can sort out which have defects that are unacceptable for retail, and can pass containers which have commercially acceptable defects.

According to the invention, a detection method for the character of individual defects should therefore be available be asked.

The above object is achieved according to the invention by a method in which a transparent container is inspected and sorted with regard to defects in the container side wall by rotating the container about its central axis while diffused light through the side wall of the container is directed, which has an intensity gradient which is variable across the light source in a direction transverse to the axis of the container rotation as a predetermined function of the respective position in this transverse direction. A camera is used to parallel the light energy sent through the container side wall within a field of view in the form of a narrow strip

to monitor the container axis of rotation. The type of sidewall defect will depend on the size of the signals generated by the light-sensitive elements of the camera, and the size of the on Defect identified in this way is dependent determined by the location of the same signals. Containers that have unacceptable defects, such as large bubbles or stones are rejected and automatically sent to the sorted out acceptable containers.

More precisely, in the embodiments of the invention described here, the intensity of the light sent through the container in the direction of the camera depending on the position in the transverse direction across the source of the diffuse light source controlled to a first and second, with Distance from one another in the transverse direction of the outer zone with essentially the same lighting intensity and to provide a third middle zone between these first and second zones in the the intensity of the diffuse illumination differs from the intensities of the neighboring outer zones differs. The lighting intensities in the outer zones can be different or im have substantially identical levels. When the intensities in the outer zones differ in size the intensity of the central zone can be uniform, linear or logarithmic between them different intensity sizes vary or a substantially uniform level between the different intensity sizes

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take in the outer zones. In the most preferred embodiment of the invention, the intensities in the first and second outer zones are substantially the same size, while the intensity in the central zone is substantially uniform and one in a corresponding manner
Has size that is different from the intensity of the outer zones.

10 IUe invention is explained below on the basis of exemplary embodiments explained in detail in conjunction with the drawing. Show it:

Figure 1

Fig. 3 is a top plan view of a container inspection system in which the invention Applies;

Figure 2

Figure 3 is an electrical and optical functional block diagram of the invention ;

Figure 3

a schematic partial diagram of the optical system of Figure 2 along Line IH-III in Figure 2;

Figures 4Λ and 5Λ

schematic diagrams similar to Figure 3 showing one embodiment of the invention, and FIGS. 4B-4D and 5B-5D are graphical representations for clarification the structure and mode of operation of the embodiment of Figures 4A and 5A;

Figures 6Λ and 7A

Schematic diagrams are similar Figure 3, representing a modified embodiment of the invention, and FIGS. 6B-6D and 7B-7D corresponding graphical representations for clarification the functioning of the embodiments of Figures 6Λ and 7Λ; and

Figures 8Λ and 9A

Figures 8B-8D and 9B-9D

schematic representations of a further embodiment of the invention and the

corresponding graphical representations of the operation of this embodiment.

Figure 1 shows a partial plan view of a container inspection system 10, which comprises a star wheel 12 which is coupled to a drive hub 14, so that it can gradually rotate counterclockwise as indicated by the arrow Id is. An infeed conveyor 18 includes a driven screw 20 which is transparent Containers 22, such as glass containers, are fed to the circumference of the star wheel 12 in the upright position. The star wheel 12 conveys the containers 22 in an arcuate path through a plurality of Inspection stations, only one of which is shown in detail at 24. A discharge conveyor 26 includes

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a driven worm 28 which picks up the containers from the periphery of the star wheel 12 after each Beliolder has been moved by star wheel through the multitude of inspection stations. There Piston 30 is coupled to solenoid 32 and can block exit to discharge conveyor 26, when actuated by the solenoid. If an unacceptable defect in a particular Container has been detected in any of the inspection stations, the piston 30 is by the Solenoid 32 operated to block exit to conveyor 26 when that container is in a Position is rotated adjacent to the exit point, so that the defective container then from Star wheel 12 is fed to a reject chute 34.

The present invention relates to the inspection station shown at station 24.

The station 24 includes a drive roller 36 which engages a container 22 and this Can rotate container counterclockwise while container 22 is in is held in a fixed axial position.

A light source 40 is arranged in the circumference of the star wheel 12 below the plane of the scar 14 and directs diffuse light radially outwards to illuminate the entire height and width of the container side wall, while the container is rotated about its axis by the drive roller 36. A camera 42 is held radially outside of light source 40 and star wheel 12 by carrier 44. the Camera 4 2 includes a variety of light-sensitive

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union elements 43 (Figure 3), preferably 230, those in a linear row parallel to the vertical axis of rotation of the container 22 at station 24 and are aligned with this axis and the vertical center line of the light source 40. A lens 46 focuses a vertical strip of the container sides and onto the array thereof Elements. The inspection system 10 described so far and the associated inspection station 24 correspond the system and the station of the patents mentioned above, so that on a further Description of items can be omitted that are included in these publications is.

As can be seen from the cited patents, the light source 40 comprises a plurality of incandescent lamps, which are arranged in three rows parallel to the axis of rotation of the container. A diffuser plate is arranged between the lamp assembly and the container, so that diffuse light from a relatively broad light source onto the container side wall and through this onto the lens 46 and the Camera 42 is directed. Signal scanning electronics compare signals from neighboring ones light-sensitive elements of the linear arrangement and feeds an event signal to an information processing unit when these signals come from neighboring photosensitive elements distinguish more than a predetermined threshold value. The information processing electronics then actuates solenoid 32 and piston 30 when the corresponding defective container is located

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moved to the exit position of the inspection station, so that the defective container in the introducing described manner to the rejection clause 34 is sorted out. As mentioned above, such an inspection and sorting technique has proven itself While it has been shown to be effective and successful, it has had problems with distinction connected between the types and sizes of the defects. The present invention is intended to these difficulties are resolved.

Figures 2 and 3 show schematic electro-optical Functional block diagrams of a presently preferred embodiment of the invention at FIG Inspection station 24. Inside the light source 40, which is shown in FIG. 1 in a top view and in FIG 2 is shown in side view, are a diffuser plate 48 and an intensity filter plate 50 arranged to take light energy from the illumination source 52 and through the side wall of the container 22 and the lens 46 onto the camera 42 to judge.

Signal sensing electronics 54 receive signals from each light sensitive point 43 (Figure 3) within the camera 42 and supplies the information processing unit 56 with sequences of signal series. The container 22 is in a direction indicated by the arrow 56 at a speed . "0, which is controlled as a function of the speed of the inspection system 10 in order to ensure that the camera 42 has a predetermined number of scans per container, i.e. 300

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Follows, or scans per container, provides. The signal sampling in the electronics 54 can therefore be adjusted accordingly. The information processing unit 56 generates an event signal when the size of signals from neighboring light-sensitive elements of a scan differs by more than a predetermined threshold value. By the term "adjacent photosensitive elements" is meant separate elements that are disposed in physical proximity to one another within the linear array of camera 42. The information processing unit 56 carries out an analysis in order to evaluate the location of a multiplicity of "events" and to determine whether a defect is present. On the basis of this analysis, the processing unit 56 controls the functioning of the solenoid 32 (FIG. 2) and the piston 30 in order to sort out defective containers.

Figure 3 is a partial side view schematically showing the filter plate 50 and the relationship of the camera 42 shows this in the direction 3-3 in FIG. To an increased coverage of sizes and types of sidewall defects and a distinction between these sizes and types in the inventive Way to perform, the optical density of the filter plate 50 is across the width SW of the Light source 40, i.e. transverse to the axis of rotation of the container, has been varied so that a non-isotropic Illumination intensity distribution is achieved in the transverse direction. With the special one described here

Embodiment of the invention, the optical density of the filter plate 50 is selected so that at least ZAv'ci laterally adjacent lighting zones 60, 62 and preferably three laterally adjacent Illumination zones 58, 60, 62 over the width SlV of the light source 40 are present. The optical Densities of adjacent zones 58, 60 and 60, 6 2 are different from one another. The center line of the Camera 42 is positioned to the center line of the central zone 60, which is between the outer zones 58, 6 2 is aligned. When there is no container 22 between lens 46 and light source 40 is or when a container is placed between the lens and the light source and rotated which has no sidewall defects is the The intensity of the light falling on the camera elements 43 is primarily a function of the optical Density at the centerline of the central zone 60. However, if a refractive sidewall defect,

ZO such as a bubble, moved in front of the camera this defect breaks the field of view of the photosensitive elements 43 within the camera 42 along a broken path to the outer zone 58 or to the outer zone 6 2. The present Invention makes use of the controlled change of the illuminance in the transverse direction in order to To be able to differentiate between types and sizes of defects.

Figures 4A and 4B, in the horizontal direction have identical scales show an embodiment of the invention. Figure 4Λ is a partial view similar to Figure 3, while Figure 4B the

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represents the optical density of the filter plate 50a (Figure 4Λ) as a function of the position in the transverse direction. In the embodiment of FIGS. 4A and 4B, the attenuation of the optical density in the outer zone 58a of the filter plate SOa is essentially 0, so that this outer zone is transparent, while the attenuation of the density of the outer zone 62a is essentially 100 % , so that this zone is opaque. Within the central zone 60a, the optical density varies linearly between a value of essentially 0 at the lateral edge which adjoins the outer zone 58a, and a value of essentially 100 % at the edge adjoining the outer zone 62a.

The signal scanning electronics 54 receive signals from each light-sensitive element 43 within the camera 42 and provide a signal in series from each element in order to generate a sequence of light signals during each scan of the linear arrangement of the camera 42 at a time t. A bubble defect 64 is shown in the field of view of a light-sensitive element 43n during various scans at times t- to t _fi .

The scanning time steps t 1 to t y are shown in the horizontal direction of FIG. 4C, these being related to the actual bubble position. Thus, scanning takes place at time t ₁ immediately before the bubble 64 has rotated into the field of view of element 43n, and scanning at time t 1 takes place immediately after the bubble 64 has rotated out of the field of view of element 43n. In the vertical direction in FIG. 4C is the actual one

Illumination intensity is shown which is detected by element 43n in each scan when the Bubble 64 passes his field of vision. The signal scanning electronics 54 provide the sequence of light signals for each scan of the information processing unit 56 is available that an "event" signal is generated when the magnitudes of adjacent flares, i.e., from elements 43n and 43m, in a sample differ by more than a predetermined threshold value. Figure 4D, taken in the horizontal direction has the same time scale as Figure 4C, shows the corresponding "difference" signal, generated by the information processing unit 56 and used to determine the present of an "event" were used. The "event" occurs in a special "place" at the Side wall of a container. The location of the "event" is determined by the number of samples, which is an indication of the angular position of the container in the manner described above, and by the number of photosensitive element that the Corresponds to the longitudinal position along the container side wall. The present sidewall inspection device, as explained in the above-mentioned patents, also performs a (linkage-0analysis by analyzing the location of a variety of "events" to determine whether there is a defect.

0 During operation, the light-sensitive changes Element 43n sensed light intensity at its field of view from the centerline of central zone 60a is ruptured by the bladder 64. If you are with the

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Sampling time t- begins, the intensity detected by element 43n immediately before the bubble 64 enters the field of view of element 43n is about 50 %, since the field of view of element 43n meets the center line of central zone 60a. Thus, the corresponding difference signal at the sampling time t i is essentially 0, since the intensities detected by the adjacent elements 43n and 43m essentially correspond to one another. At the sampling time t ~, however, when the front edge of the bubble 64 just penetrates the field of view of the element 43n while it is moving in the direction 66 relative to the stationary filter plate 50a and the camera 42, the intensity detected by the element 43n increases to about 100 $ because the leading edge of the bladder 64 breaks the field of view of the element 43n into the substantially transparent outer zone 58a. The corresponding difference signal at the sampling time tj assumes an essentially positive value, since the intensity detected by element 43n is considerably greater than that detected by element 43m. If, at the scanning time t, the front edge of the bubble 64 moves further into the field of view of the element 43n, the intensity detected by the element 43n only increases up to about 75 ° s, since the refraction properties of the front edge are less strong and a refraction of the Effect the field of view of the element 43n only up to the outer area of the central zone 60a. Thus, the corresponding difference signal at the sampling time t is still a positive value, since that from the element

43n detected intensity is even greater than the intensity detected by element 43m. At the scanning time t 1, when the light-refracting front edge of the bubble 64 has just moved out of the field of view of the element S 43n, the intensity detected by the element 43n returns to about 50 %, since the essentially parallel surfaces of the bubble 64 the field of view of the Element 43n no longer break. The corresponding difference signal thus returns to the value 0 at the sampling time t 1. At the scanning time tr, the rear edge of the bubble 64 begins to move into the field of view of the element 43n. The detected intensity drops to about 25 ° δ, since the refractive properties of the rear edge are not so strong and cause a refraction of the field of view of the element 43n only up to the outer area of the central zone 60a. Thus, the corresponding difference signal at the sampling time tr becomes a negative value, since the intensity detected by element 43n is somewhat less than the intensity detected by element 43m. At sampling time te, when the rear edge of the bubble 64 moves completely into the field of view of the element 43n, the detected intensity drops to 0 because the rear edge of the bubble 64 extends the field of view into the outer zone 6 2a, which is essentially opaque , breaks. Thus, the corresponding difference signal has at the sampling time t. a considerably negative value since the intensity sensed by element 43n is considerably lower than the intensity sensed by element 43m. At time t- after the rear margin

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of the bubble 54 has moved out of the field of view of the element 43n, the detected intensity is again about 50 %, since the field of view of the element 43n coincides with the center line of the central zone 60a and is not broken by a defect. The corresponding difference signal at time t- is thus essentially 0, since the intensities detected by elements 43n and 43m essentially correspond to one another.

Thus, the difference signals associated with a bubble or some refractive defect produce a computer-identifiable "handwriting" that has a positive peak signal which decreases to a negative peak value. The information processing unit 56 determines the size of the bubble 64 by performing the analysis described above, which provides an indication of the transverse dimension of the bladder 64 by the number of scans between the positive peak and negative peak difference signals corresponding to the front and corresponding to the rear edge of the bladder 64, counts. The information processing unit 56 is like this programmed to issue a reject signal 32 if the number of samples is a exceeds a predetermined threshold indicating the presence of a large bubble, so that Containers with large bubbles will be rejected and containers with small bubbles will not be rejected \\ r because they are accepted by the trade will. The same analysis would be performed and the same "handwriting" would be obtained

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if the bubble 64 were large enough to accommodate the field of view of various photosensitive elements 43 to influence. A corresponding "handwriting" would be obtained for any photosensitive element that varies only in transverse dimension.

The present invention not only provides the sidewall inspection apparatus with the ability to detect refractive defects by optical amplification and distinguish between large and small refractive defects, but also makes it maintain the ability to detect opaque defects. Such opaque defects absorb light energy and are visible in the present invention as dark points on a "gray" background. The opaque defect creates a different "handwriting" of difference signals than a light-refracting defect. In FIGS. 5Λ to 5D, an opaque defect or “stone” 68 is shown in the field of view of the light-sensitive element 43n. In operation, the light intensity sensed by element 43n varies because its field of view is blocked by the "stone" 68 from the centerline of central zone 60a. At the scanning time t ~, precisely when the front edge of the fine element 68 penetrates the field of view of the element 43n, the intensity detected by the element 43n drops to 0, since the stone is opaque. The corresponding difference signal to the scanning part t ₉ thus has a considerably negative value, since the intensity detected by element 43n is considerably less than the intensity detected by element 43m. The same analysis hits

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towards the light intensity detected by element 43n at the sampling times t 1 to t g. So is the "handwriting" produced by stone 68 can be immediately distinguished from that produced by bubble 64 "Handwriting"; The "handwriting" of a bite is made up of a positive peak and a negative Peak value is flanked, while the "handwriting" of a stone merely consists of negative Peaks. Thus, this embodiment of the invention enables the sidewall inspection device can detect the presence of an opaque defect and at the same time is able to detect refractive defects through to detect optical gain and between small and large refractive defects too differentiate.

Figures 6A-6D and 7A and 7D, which correspond to Figures 4A-4D and 5A-5D, show another one Embodiment of the invention. In Figures 6A and 6B, there is the attenuation of the optical density essentially 0 in the outer zone 58b of the filter plate 50b, so that this zone is transparent, while the attenuation of the density of the outer zone 62b is essentially $ 100 so that this Zone is opaque. The optical density is essentially within the central zone 60b 50 ° ό.

The signal sensing electronics 54 receive signals from each photosensitive element 43 within the Camera 42 and in rows provides a signal from

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each element is available to generate a sequence of signals from the elements during each scan of the linear array in camera 42 at time t. A bladder defect 64 is shown in the field of view of a light-sensitive element 43n during various scans at times t2 to t1. The horizontal scale in FIG. 6C shows the sampling steps t .. to t- and relates them to the actual bubble position. Thus, the sample takes place at time t. takes place immediately before the rotation of the bubble 64 into the field of view of the element 43n, while the scanning at time t _{7 is carried out} immediately after the rotation of the bubble 64 out of the field of view of the element 43n. The vertical scale of Figure 6C shows the actual intensity of illumination detected by element 43n for each scan as bubble 64 passes its field of view.

The signal evaluation electronics 54 conduct the sequence of signals for each scan of the information processing unit 56, which generates an "event" signal when the magnitudes of signals from neighboring elements, i.e. from the elements 43n and 43m, differ by more than a predetermined threshold value in one scan. Figure 6D, which has the same horizontal time scale as Figure 6C, shows the corresponding Difference signals received from the information processing unit 56 and used to determine the presence of an "event". The "event" occurs at a

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special place on the side wall of a container. This point is defined by the number of samples, which is an indicator for the angular position of the container in that described above Way offers, and by the number of the photosensitive Element that corresponds to this position in the longitudinal direction along the container side wall. The present sidewall inspection apparatus as used in those mentioned above Patent specifications is described, also performs an analysis by taking the local position analyzes a variety of "events" to determine if a defect is present.

In operation, the light intensity detected by element 43n changes because of its field of view is broken by the bladder 64 from the center line of the central zone 60b. At the sampling time t .., immediately before the bubble 64 enters the field of view of the element 43n, the intensity detected by element 43n is about $ 50, since the field of view of the element 43n hits the center line of the central zone 60b. Thus is the corresponding difference signal at sampling time t .. essentially equal to 0, since that of the neighboring elements 43n and 43m detected intensities essentially correspond to one another. At the sampling time

SO point ty, however, when the leading edge of the bladder 64 just enters the field of view of the element 42n while moving in the direction

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66 moved relative to the stationary filter plate 50b and to the camera 42, the intensity detected by the element 43n increases to approximately 100 % as the front edge of the plate 64 breaks the field of view of the element 43n into the essentially transparent outer zone 58b. The corresponding difference signal at the sampling time t ^ is a considerably positive value, since the intensity detected by element 43n is considerably greater than the intensity detected by element 43m. At the sampling time t ^, when the front edge of the bubble 64 has moved further into the field of view of the element 43n, the intensity detected by the element 43n drops to 50 % . The corresponding difference signal at the sampling time point t is therefore essentially 0, since the intensity detected by element 43n corresponds approximately to the intensity detected by element 43m. The same applies to times t. and tr to. At time t, - when the rear edge of the bubble 64 has moved completely into the field of view of the element 43n, the detected intensity drops to 0 as the rear edge of the bubble 64 breaks the field of view into the outer zone 62b, which is im is substantially opaque. The corresponding difference signal thus has a considerably negative value at the sampling time tg, since the intensity detected by element 43n is considerably less than the intensity detected by element 43m. At the sampling time ty, after the rear edge of the bubble 64 has moved out of the field of view of the element 43n, the detected intensity is again about 50 % , since the field of view of the element 43n is on the center line of the central zone

60b meets and is not broken by a defect. Thus is the corresponding difference signal at sampling time t ~ essentially o, since the intensities detected by elements 43n and 43m substantially correspond to one another. As in Figures 4A-4D, the information processing unit determines 56 determines the size of the bubble 64 by performing the analysis described above which provides an indication with respect to the Transverse dimension of the bubble 64 by counting the number of samples between the positive and the negative peak difference signals corresponding to the leading and trailing edges of the bladder 64, supplies. The information processing unit 56 is programmed to issue a rejection signal 32 provides when the display samples exceed a predetermined threshold, indicating the presence of a large bubble, so containers with large bubbles are rejected and containers with small bubbles will not be rejected because they will be accepted by the trade will. The same analysis would be performed and the same "handwriting" would be obtained if the bubble 64 were large enough to influence the field of view of various elements 43. One corresponding "handwriting" would be given for each element obtained, the dimension of which varies only in the transverse direction.

Figures 7A to 7D show an opaque defect or "stone" 68 in the field of view of the element 43n. In operation, the light intensity sensed by element 43n will vary as its field of view is from the center line the middle zone 60b through the stone 68

blocked. At the sampling time t ₂ , when the front edge of the stone 68 just penetrates the field of view of the element 42n, the intensity detected by the element 43n drops to 0, since the stone is opaque. Thus, the corresponding difference signal at the sampling time X ~ has a considerably negative value, since the intensity detected by element 43n is considerably less than the intensity detected by element 43m. The same analysis relates to the light intensity detected by the element 43n at the sampling times t 1 to t 1. The "handwriting" generated by the stone 68 can thus be distinguished immediately from the "handwriting" generated by the bubble 64; the "handwriting" of a bubble is flanked by a positive peak value and a negative peak value, while the "handwriting" of a stone consists only of negative peaks. Thus, by this embodiment of the invention, the side wall inspection apparatus can detect the presence of an opaque defect and at the same time determine refractive effects by optical amplification and distinguish between small and large refractive defects.

Figures 8A-8D and 9A-9D, which correspond to Figures 4A-4D and 5A-5D, show a further embodiment of the invention. In Figures 8A and 8B, the attenuation of the optical density in the outer zones 58C and 62C of the filter plate 0.5OC is essentially zero, so that the zones are transparent. Within the central zone 6OC, the optical density is essentially 50 %.

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In operation of this embodiment, the light intensity sensed by element 42n varies as its field of view is refracted by bladder 64 from the centerline of central zone 6OC. To sampling instant t .. immediately before the bubble 64 enters the field of view of the member 43n, 43n from the element detected intensity is approximately 50%, since the field of view of the member 43n is incident on the center line of the central zone 6oC. Thus, the corresponding difference signal at the sampling time t .. is essentially 0, since the intensity detected by adjacent elements 43n and 43m is essentially the same. At scan time t-, however, when the leading edge of bubble 64 is just entering the field of view of element 43n while moving in direction 66 relative to stationary filter plate 50C and camera 42, the intensity detected by element 43n increases to about 1001 because the leading edge of the bladder 64 breaks the field of view of the element 43n into the substantially transparent outer zone 58C. The corresponding difference signal at the sampling time t- assumes a considerably positive value, since the intensity detected by element 43n is considerably greater than the intensity detected by element 43m. At the sampling times t, -tr, when the front edge of the bubble 64 has moved further into the field of view of the element 43n, the intensity detected by the element 43n drops to about 50%. The corresponding difference signals at the sampling times t, -tr therefore have essentially a zero value. At the sampling time t ^, when the rear edge of the bladder 64 has moved completely into the field of view of the element 43n, the reverses

sensed intensity returns to 1001 as the trailing edge of bubble 64 breaks the field of view into outer zone 62C which is essentially transparent. The corresponding difference signal thus has a considerably positive value at the sampling time tg, since the intensity detected by element 43n is considerably greater than the intensity detected by element 43m. At the sampling time t ₇ , after the rear edge of the bubble 64 has moved out of the field of view of the element 43n, the detected intensity is again about 50%, since the field of view of the element 43n hits the center line of the middle zone 6OC and not through a defect is broken. The corresponding difference signal at the sampling time t- is thus essentially 0, since the intensity detected by the elements 43n and 43m is essentially the same.

The differential signals associated with a bite or any corresponding defect generate at In this embodiment, a computer-identifiable "handwriting" comprising a pair of positive peaks included. The information processing unit 56 determines the size of the Bladder 64 by performing the aforementioned analysis which is an indication of the transverse dimension the bubble 64 by counting the number of samples between the positive peak difference signals, which correspond to the leading and trailing edges of the bladder 64 provides. The information processing unit 56 is programmed to provide a reject signal 3 2

represents when the number of samples is a predetermined Exceeds threshold value indicating the presence of a large bubble, so that container rejected with large bubbles and containers with small bubbles not rejected because they are accepted by the trade. The same analysis takes place and the same "handwriting" is obtained when the bubble 64 is large enough to allow the field of view of various elements 43 to influence. A corresponding "handwriting" is obtained for each element of the only the transverse dimension varies.

Figures 9Λ-9Ι) show an opaque defect or a "stone" 68 in the field of view of the light-sensitive element 43n. In operation, the light intensity detected by element 43n fluctuates because its field of view is blocked by stone 68 from the center line of central zone 60c. At the sampling time t ~, precisely when the front edge of the stone 68 penetrates the field of view of the element 43n, the intensity detected by the element 43n drops to 0 because the stone is opaque. The corresponding difference signal thus has a considerably negative value at the sampling time t ₇ , since the intensity detected by element 43n is considerably less than the intensity detected by element 43m. The same analysis applies to the from element 43n at the sampling times t, -t,. detected light intensity. The “handwriting” produced by stone 68 can thus be immediately distinguished from that produced by bubble 64

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"Handwriting"; becomes the "handwriting" of a bubble flanked by positive peaks, while the "handwriting" of a stone consists solely of negative Peaks. Thus, in this embodiment of the invention, the side wall inspection device detect the presence of an opaque defect while being able to at the same time is to detect refractive defects through optical amplification and between small and to distinguish large refractive defects.

The various embodiments disclosed herein the invention thus not only enable the detection of opaque and refractive defects, but also allow a distinction between such defects, both according to the Type as well as size. Of course, the bubble defects 64 are in Figures 4A, 6A, and 8A and the stone defects in FIGS. 5A, 7A and 9Λ are shown for reasons of comparison so that they be identical in size. It is also clear that the sensitivity of the different execution Shapes of the invention differ from refractive or opaque defects Size can be controlled by varying the scanning steps, for example by variation of the transverse dimensions D, W and E of the filter zones 58, 60 and 62 in FIG. 3, by varying the dimension C between the center line of the camera and the abutting edges of the zones 58, 60 and / or by varying the whole

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effective width SW of light source 40. It is presently preferred that each filter zone 58, 60, 6 2 one Uniform weakening of the optical density in the longitudinal direction, i.e. in the vertical direction of the container axis, possesses, although this density also in the longitudinal direction according to the principles of the above American patent application 424 68 7 can be varied if so desired should. For containers with a narrowing neck (Figure 2) it is proposed that the Width W of the middle zone compared to the neck increases with decreasing neck diameter.

The signal sampling electronics 54 and the information processing unit 56 (Figure 2) are described in greater detail in U.S. Patents 4,378,494 and 4,378,495 referenced above.

As explained above, the broad concept is Inspection and sorting of transparent containers by allowing diffuse light through a container side wall directed to generate an intensity gradient as a given function of position varies in a certain direction, and the specific application of this concept in which the intensity varies in the longitudinal direction parallel to the container axis, subject of the above mentioned American patent application 4 24 68 7. The special embodiments of this broad Concept illustrated in Figures 6A-6D, 7A-7D, 8A-8D and 9A-9D and in connection therewith

35U313

have been explained, are the subject of American patent application 601 759 from 19. April 1984, which priority is claimed in the present application.

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Claims (1)

35U313, _Λ Claims 1. Device for detecting defects in the side walls of transparent containers and for Sorting out the detected defects having containers with devices for positioning a Container and for rotating the container around its central axis, a light source for directing diffuse light through the side wall of a positioned and rotated container, light sensing devices, which are arranged to receive the light energy penetrating through the container side wall, means for detecting of side wall effects in the container as Function of the intensity of the light received by the light scanning devices and \ Means for rejecting a container in which a defect is detected is indicated by the fact that the diffuse light emitted by the light source (40) has an intensity which is in the transverse direction the axis as a predetermined puncture of the position varies across the width of the light source. 2. Apparatus according to claim 1, characterized marked that the light source (40) the diffuse light in at least two zones (58, 60) or (58a, 60a or 58b, 60b or 58c, 60c), which are laterally adjacent to each other, is available, in these Zones the intensity of the light in different functions of position in the transverse direction 35U313 varies over the Γ-rcite of the light source. ?. Apparatus according to claim 2, dad ure h ge indicates that the light source (40) the diffuse light in three zones (58-62, 58a-62a, 58b-62b, 58c-62c) laterally adjacent to each other in a direction transverse to the axis, provides, each of these zones, means for weakening the intensity of the penetration Includes light as a predetermined puncture of the position in this transverse direction and each of these functions being different from the puncture belonging to the adjacent zone. 4. Apparatus according to claim 3, characterized in that that the intensities of the diffuse light penetrating through the outer zones (58a, 62a, 58b, 62b, 58c, 62c) are related on the position in the transverse direction are essentially constant and that the intensity of the diffuse Light that penetrates through the central zone (60a, 60b, 60c) differs from the essentially constant Differs intensities. 5. Apparatus according to claim 4, characterized by dadu r ch, that the substantially uniform intensities in the outer zones (58a, 62a, 58b, 62b) have different intensity levels and that the intensity in the middle zone (60a, 60b) between the different intensity levels. 35H313 6. Apparatus according to claim 4 or 5, characterized geke nnzeich that the intensity in the middle zone (60a) as uniform Function of the position in the transverse direction over the middle zone between the essentially uniform intensities in the outer zones f58a, 62a) varies. 7. Apparatus according to claim 6, characterized in that that the intensity in the central zone (60a) as a substantially linear function of the position in the transverse direction varies over the central zone. 8. Apparatus according to claim 4, characterized in that that the intensity of the diffuse light in the central zone (60b, 60) is essentially related to the position in the transverse direction is even and differs from the sities in the outer zones (58b, 6 2b; 58c, ü2c) differs. 9. Apparatus according to claim 8, characterized in that that the diffuse light in the outer zones (58b, 62b) has unequal, essentially constant intensities in the transverse direction owns. 10. The device according to claim 9, characterized in that that the intensity in the middle zone (60b) between the unequal intensities lies in the outer zones. 35H313 Π. Apparatus according to claim 8, d a by g e kcnnzei c Ii net that the substantially uniform intensities in the outer zones C58c, 62c) are essentially the same and that the intensity in the central zone (60c) is related to on the position in the transverse direction is substantially uniform and different from the intensities differs in the outer zones. 12. The device according to claim 11, characterized in that that the intensity in the middle zone (60c) is less than that in the outer zones (58c, 6 2c). 13. Device according to one of the preceding claims, since you gcken n sign that the light sensing devices (42) comprise a plurality of photosensitive elements (43) shown in a linear arrangement substantially parallel to the axis, and that the detection means (54, 56) Include devices responsive to these elements and the intensity of the light received by each element at each step of the container rotation with the intensity of the light received by the neighboring element, as well as devices that act on the oil I devices address and defects (64, 68) in the container side wall as a function of a difference identify in these intensities. 11. The device according to claim 13, characterized in that the identification devices Include devices responsive to the comparison devices and between species - ⁵ - 35U313 these defects (64, 68) as a function of the difference differentiate. 15. Device according to one of the preceding claims, characterized et that they further conveying devices (18, 26) for feeding and removing containers (22) one after the other to and from the positioning and breeding devices (12, 14, 36, 38) and devices (3 2) for the optional actuation of the rejection devices (30) for the disposal of containers from the conveyors when a defect has been detected. 16. Process for sorting out transparent containers, that have defects in the container wall, the optical transmission properties give way affect the container side walls, characterized by the following steps: (a) rotating the container about its central axis, (b) Directing a source of diffuse light through the side wall of the container, the intensity of the light being in a direction transverse to the Axis varies as a given function of the position across the light source in the transverse direction, (c) Arranging a camera having a plurality of photosensitive elements which are shown in a linear arrangement are provided / such that the arrangement is parallel in one direction extends to the axis so that a field of view is formed parallel to that axis, Cd) Identifying defects in the container side wall as a function of differences in light energy from neighboring light-sensitive ones Elements has been detected, and (e) Reject a container in which a defect has been identified in this way, in order to in this way to sort out a defective re-container against acceptable containers. 1517. The method according to claim 16, characterized in that it is a characteristic That is, step (b) comprises the step of filtering the intensity of the light emitted from the light source through the container sidewall includes diffuse light to form at least two zones in which the intensity of the The position of the light varies in different functions in the transverse direction. 13. The method according to claim 17, characterized in that that step Cb) the step of filtering the intensity of the directed from the light source through the container side wall Diffuse light includes, such that three laterally adjacent zones across the transverse dimension of the light source, with the intensity of the light in each of these zones varies as a given function of the position in the transverse direction, which is different from that of the neighboring Zone differs. - 7 - 35U313 19. The method according to claim 18, d a d u r c h g e characterize t that step (b) comprises the following steps: (bl) Filter the intensity of the diffuse light in the outer zones so that essentially uniform intensities with respect to position in the transverse direction are obtained, and Cb2) Filtering the intensity of the diffuse light i η of the middle zone, so that an intensity function with respect to the position is obtained in the transverse direction, which differs from the two in iesentl ichen uniform intensities differs. 20. The method according to claim 19, characterized in that that the essentially uniform intensities in the outer zones have different intensity levels and that the intensity in the middle zone between these different intensity levels lies. 21. The method according to claim 19 or 20, d ad u r ch marked that the intensity in the middle zone as a uniform function of the position in the transverse direction over the middle zone Zone varies between the essentially uniform intensities in the outer zones. 22. The method according to claim 21, characterized It is indicated that the intensity in the middle zone as essentially linear Function of the position in the transverse direction varies over the central zone. ZTi. A method according to claim 19, characterized in that step (b) comprises the step of filtering the intensity of the diffuse light penetrating through the container side wall between the light source and the container such that three laterally adjacent lighting zones over the dimension of the Light source are formed transversely to the axis, the intensity of the diffuse light in the outer zones being substantially uniform with respect to the position in the transverse direction of the axis and the intensity in the central zone being substantially uneven with respect to the position in the transverse direction of the axis ig and is different from the intensities in the outer zones. 1. The method according to claim 23, dadur c h indicates that step (b) the Comprises the step of filtering the diffuse light in the outer zones such that unequal, substantially uniform intensities are achieved in the outer zones.
25th 25. The method according to claim 24, characterized in that step (b) includes the additional Step of filtering the intensity in the middle zone to a level that is between the Intensities lies in the outer zones, includes. - ⁹ - 35U313 2f>. Method according to claim 23, d a d u r c h g c mark Inet that step (b) comprises the step of filtering the diffuse light in the outer zones such that the same, im substantially uniform intensities can be achieved in the outer zones. 27. The method according to claim 26, characterized in that that step (h) the additional s-step of the filter-ns of the intensity in the middle zone in such a way that it is less than the intensity in the outer ones Zones. 28. The method according to any one of the preceding claims, characterized in that it has the additional step (f) of controlling the dimensions of the zones in one direction transverse to the axis and the position of the photosensitive Means relative to the zones included to Scitenwanddefect a given Minimum size and of a given type.