EP3510877A2 - Device and method for inspecting rod-shaped items for the tobacco industry - Google Patents

Abstract

The invention relates to a device (32) and a method in the tobacco processing industry for optical testing of rod-shaped articles (2). The rod-shaped articles (2) are each a compilation of several segments (6a..6e). The device (32) comprises a conveying member (34) for the transverse-axial conveying of the rod-shaped articles (2), which comprises a plurality of receiving troughs (36) in which the rod-shaped articles (2) are receivable. The device (32) further comprises an image acquisition device (18) with which the rod-shaped articles (2) arranged in the receiving troughs (36) can be detected during the transverse-axial conveyance. The image acquisition device (18) comprises a camera arrangement (14) with a plurality of cameras (16a..16e) for image acquisition, which are arranged next to one another in a longitudinal extension direction (A) of the receiving troughs (36). The cameras (16a..16e) comprise an entocentric objective (4a..4e). The image field (20a, 20b) of the cameras (16a..16e) in each case comprises a central imaging region (22a, 22b) in which the objective (4a..4e) images without distortion and which is separated from an imaging edge region (24a, 24b). surrounded with greater distortion. The cameras (16a..16e) are arranged such that the central imaging regions (22a, 22b) of adjacent cameras (16a..16e) overlap one another. A processing unit (38) is set up to calculate the image data captured by at least two cameras (16a, 16e) in the central imaging areas (22a, 22b) to form a common image of the camera arrangement (14).

Description

The invention relates to an apparatus of the tobacco processing industry for optically inspecting rod-shaped articles of the tobacco processing industry, wherein the rod-shaped articles are each an assembly of several segments, and wherein the device comprises a conveying member for Queraxialen promotion of rod-shaped articles and the conveying member a plurality of receiving troughs in which the rod-shaped articles are receivable or received, wherein the device further comprises an image capture device with which the arranged in the receiving troughs rod-shaped articles are detected or detected during the cross-axial promotion. Furthermore, the invention relates to a method for optically inspecting rod-shaped articles of the tobacco-processing industry, wherein the rod-shaped articles are each an assembly of several segments and are conveyed by a conveying member transversely axially in a receiving trough of the conveying member.

Rod shaped article of the tobacco processing industry, which is a compilation are of several segments, are known for example as a multi-segment filter. When composing the filter segments, errors may occur, such as swapping filter segments, missing a filter segment, wrong position, or inserting a filter segment of the wrong length. Furthermore, gaps between filter segments may occur or the filter segments may be tilted relative to each other.

To detect such errors during manufacture, is from the EP 1 769 689 A1 a device for measuring properties of multi-segment filters or collections of filter segments in the tobacco processing industry known. The multi-segment filter arrangement is illuminated with a line laser. The reflected light on the surface of the filter segments is received by means of a line scan camera, the data collected by the line scan camera are evaluated accordingly.

Another device, are tested in the multi-segment filter during the transverse-axial promotion on a conveyor drum, for example, from DE 10 2009 041 320 A1 known. The conveyor drum is provided with a lighting device. The multi-segment filters are accommodated in a slotted receptacle, for example a receiving trough, of this conveying element. An additionally provided sensor device absorbs the radiation which passes through the multi-segment filter or through the arrangement of a plurality of segments present in the receiving trough. The observation takes place via a mirror, the emerging radiation is collimated by means of a lens and directed to a CCD camera. In this transmitted light method, especially with activated carbon filled filter segments are well detectable.

If the distance between the segments of a rod-shaped article, which is conveyed on a conveyor drum transversely, be measured with high accuracy, a line scan camera with very high resolution would be required in the above-mentioned conventional solutions. Such However, cameras are expensive to operate and also expensive to buy. In addition, the segment arrangement would have to be imaged without distortion or distortion on the line scan camera, for which a telecentric optics is required. In the case of a telecentric optic, the light bundles from the object area under consideration enter the front lens of the objective parallel to the optical axis. For this reason, it is required that a telecentric lens has a front lens which is equal to or larger than a maximum size of the object to be viewed. Among other things, this requirement means that telecentric optics are very expensive. In addition, telecentric optics are quite large and heavy, so that the design complexity for the realization of the measuring arrangement is correspondingly complex and expensive. In addition, a large space is claimed, which often leads to problems in practice in practice.

The object of the present invention is to provide an apparatus of the tobacco processing industry for optically inspecting rod-shaped articles of the tobacco processing industry and a method for optically inspecting rod-shaped articles of the tobacco processing industry, with which a precise examination of the rod-shaped articles with high Resolution can be made, but the design effort should be kept low.

The object is achieved by a device of the tobacco processing industry for optical testing of rod-shaped articles of the tobacco processing industry, wherein the rod-shaped articles are each an assembly of several segments, and wherein the device comprises a conveying member for Queraxialen promotion of the rod-shaped article and the conveying member a plurality of receiving troughs in which the rod-shaped articles are receivable or received, wherein the device further comprises an image capture device with which the arranged in the receiving troughs rod-shaped articles are detected or detected during the transverse axial promotion, this device is thereby developed in that the image capture device a camera arrangement having a plurality of cameras for image acquisition, wherein the cameras are synchronized in particular for simultaneous image acquisition and wherein these cameras are arranged side by side in a longitudinal direction of the receiving wells, and wherein each camera of the camera assembly comprises an entocentric or at least approximately entocentric lens and with this an object field, which passes through the arranged in the receiving troughs rod-shaped article during the cross-axial promotion, images on an image field, wherein the image field comprises a central imaging area in which the lens without distortion or at least with a distortion below a predetermined or predeterminable limit value maps of is surrounded by an imaging edge region with greater distortion, wherein the cameras are arranged in the camera arrangement such that the central imaging regions of adjacent cameras overlap each other wherein the image acquisition device further comprises a processing unit which is set up to charge the image data captured by at least two, in particular all, cameras of the camera arrangement in the central imaging regions to a common image of the camera arrangement.

The device according to aspects of the invention is based on the technical consideration that the conventionally operated effort, especially the use of a telecentric optics and the use of a large line scan camera with a high resolution, can be avoided by using a camera assembly which has a plurality comprising juxtaposed individual cameras. The individual images captured by these individual cameras are billed together after the acquisition. In this context, it is advantageous if the cameras are synchronized, ie the frames of the cameras are detected at the same time. Such a camera arrangement is in sum cheaper than a correspondingly large line scan camera, since it can act at the individual cameras available at a manageable price standard products. It is also advantageous that no special optics, such as a telecentric optics, but conventional entocentric optics can be used. This represents a further considerable cost advantage. The property of entocentric optics which is fundamentally disadvantageous for the measurement task, namely a distortion, for example a pincushion-shaped or barrel-shaped distortion, plays only a minor role in the camera arrangement according to aspects of the invention. It does not affect the measurement negatively. This is achieved by excluding those peripheral areas of the image area in which the distortion is large from the measuring task. In other words, only those imaging regions of the cameras are used for the measuring task, which are located in a central region in which the entocentric optics also display virtually distortion-free.

Finally, it is extremely advantageous that the device claimed according to aspects of the invention, no large space. The entocentric optics are not overly large and can be purchased in good quality at a reasonably low price. In addition, the object distance can be chosen to be relatively small, for example less than 100 mm, 200 mm, 300 mm or less than 500 mm.

The camera arrangement is preferably arranged such that without further optical elements, such as one or more prisms or the like, the rod-shaped articles are imaged directly with the entocentric lenses of the individual cameras.

The cameras of the camera arrangements are those with an area sensor (2D image sensor). In particular, no line scan cameras are used. The cameras of the camera device are in particular synchronized. In other words, in particular, an image capture takes place simultaneously with all the cameras of the camera arrangement.

In particular, the camera arrangement comprises such a large number of individual cameras that it is possible to completely image the rod-shaped article in the central areas of the cameras as a whole. After subsequent billing of the captured image data to a common image, there is a complete image of the rod-shaped article for subsequent analysis.

The device is further developed, in particular, in that the processing unit is further adapted to quantitatively measure at least one gap between two adjacent segments and / or at least one length of a segment of the rod-shaped articles.

In addition to a quantitative evaluation, a qualitative evaluation can also be carried out. For example, it is possible to judge a quality of the cut edge of the individual segments. This is advantageously possible because with the camera arrangement of the device according to aspects of the invention, an optical inspection in supervision, ie directly from above, takes place. The viewing direction is at least approximately perpendicular to a longitudinal extension direction of the rod-shaped article. If, in comparison, an optical test with a single entocentric objective would take place, a view of the end faces of the individual segments would result, at least in the case of the outer segments, on account of the angle of vision becoming flatter in the edge regions. Such a perspective makes a qualitative assessment of the cut edges difficult or inaccurate. Also, a quantitative measurement of the gaps between the adjacent segments or a length of the segments of the rod-shaped article is difficult and inaccurate due to the blurred edge shown. With the device according to aspects of the invention, however, this is possible at a substantially lower cost and a much smaller space in the same or similar quality and accuracy, as is the case with the use of a telecentric lens.

With regard to the quantitative evaluation, the device is also particularly characterized in that the image acquisition device and the processing unit are further adapted to at least one in the longitudinal direction of the receiving wells oriented distance between two adjacent segments and / or oriented in this longitudinal direction length of a segment, in particular with an accuracy of better than 0.1 mm, to eat.

For example, the resolution of the cameras of the camera arrangement is chosen so that with selected object distance and the optics used, the resolution of the camera is large enough to achieve the desired resolution. For example, the object distance is 200 mm and a maximum object length is also 200 mm. A resolution of the camera is for example between 8 and 10 thousand pixels. For example, more than 4 cameras are used in the camera arrangement. Furthermore, for example, the camera arrangement comprises 4, 6, 8 or 10 cameras. Advantageously, the device allows a very accurate measurement of the width of the individual spaces between the segments and a very accurate measurement of the length of the segments of the rod-shaped article.

The device is further developed in particular in that the processing unit is further configured to calibrate the cameras of the camera arrangement by evaluating the image data of adjacent cameras acquired in the overlapping central image areas and determining a shift vector between the image areas of adjacent cameras.

The displacement vector determined as part of the calibration is applied to the subsequent exposures in order to align them with each other, so that in sum, ie in the common image, there is an objectively and faithfully correct representation of the rod-shaped article. Of course, this calibration takes place especially for all cameras. It is also possible to repeat the calibration during the measuring operation, for example at regular intervals.

It is further provided in particular that the cameras of the camera arrangement are sensitive in the visible spectral range. There is, for example, an illumination of the rod-shaped article in the overhead light or transmitted light. It is further provided in particular that the lighting is a continuous light or in particular a flash or the like. In other words, for example, there is no continuous lighting. For this purpose, a synchronization of the flash with the camera device is required. This synchronization is taken over, for example, by the processing unit. A corresponding flashlight is actuated simultaneously with a trigger of the individual cameras of the camera arrangement. The image acquisition thus takes place at the moment when the rod-shaped article, which is received in the receiving trough, is illuminated by the flashlight. The flash device is thus synchronized with the cameras of the camera device. Furthermore, the image capture takes place when the rod-shaped article, which is received in the receiving trough, is transported through the image field of the camera assembly. It is further provided according to a further embodiment, in particular, that the conveying member is a conveyor drum on which the rod-shaped articles are conveyed transaxially.

The object is further achieved by an arrangement of the tobacco processing industry, comprising a device according to one or more of the aforementioned embodiments, wherein the arrangement further comprises a rolling device and wherein the device for optically testing rod-shaped articles with respect to a conveying direction of the rod-shaped articles upstream the rolling device is arranged.

The rolling device comprises, for example, a conveyor drum on which the rod-shaped articles are conveyed transaxially and with which the rod-shaped articles are fed to a roller block. The device for optically testing the rod-shaped articles is arranged, for example, so that the composition of the segments is detected directly on the conveyor drum, shortly before the assembly into a leaflet is rolled up. In other words, the device for optical testing is arranged immediately before the rolling process.

• einem Vorhandensein eines oder mehrerer Segmente,
• einer Anzahl der in der Zusammenstellung vorhandenen Segmente,
• einer Lage und/oder Art der Segmente, wobei unter der Art eines Segments beispielsweise dessen Typ und Dimension zu verstehen ist,
• einer Größe zumindest einer Lücke zwischen zwei benachbarten Segmenten,
• einer Größe einer Länge zumindest eines Segments und/oder
• einem Vorhandensein und/oder einer Lage eines Blättchens, welches zur Umhüllung der Zusammenstellung der Segmente in einer Rollvorrichtung vorgesehen ist.

According to further aspects, it is provided that with the device for the optical testing of rod-shaped articles, a parameter set is obtained which in particular completely describes the composition of a plurality of segments. For example, this parameter set includes information about:

• a presence of one or more segments,
• a number of segments present in the compilation,
• a position and / or type of segments, the type of segment being understood, for example, as its type and dimension,
• a size of at least one gap between two adjacent segments,
• a size of a length of at least one segment and / or
• a presence and / or a position of a leaflet, which is provided for wrapping the composition of the segments in a rolling device.

According to a further embodiment, the arrangement is set up to carry out a process control and / or regulation on the basis of this parameter set. For this purpose, it is set up, for example, to make an association between a rod-shaped article and a parameter set. If a rod-shaped article does not meet a predefined quality criterion due to a deviation of one or more parameters from a predefined setpoint value, the arrangement is further configured, for example, to eject this rod-shaped article after the rolling process and exclude it from further processing. It is further provided in particular that the parameter set or individual values / parameters are used to follow-up and / or regulate the process of assembling the segments. For example, if too little gap is detected between segments, then this information can be used to compile the compilation readjust so that the desired setpoint is maintained in the subsequent compilations.

Furthermore, it is provided in particular that the parameter set is used in the context of quality control for the detection of sources of error. For example, faulty base materials can be identified.

The object is also achieved by a method for optically inspecting rod-shaped articles of the tobacco-processing industry, wherein the rod-shaped articles are each an assembly of a plurality of segments and conveyed by a conveying member transversely axially in a receiving trough of the conveying member, this method being developed thereby that the rod-shaped articles are detected during the cross-axial conveying with a plurality of cameras, wherein in particular the cameras are synchronized and the rod-shaped articles are detected in particular simultaneously and wherein these cameras are arranged side by side in a longitudinal direction of the receiving well, and wherein each camera is a rod-shaped Articles partially comprehensive object field entocentric or at least approximately entczentrisch on an image field maps, wherein the image field comprises a central imaging area in which a lens of the camera distortion f or at least with a distortion below a predetermined or predefinable limit surrounded by an imaging edge region with greater distortion, and wherein the rod-shaped article is imaged such that the central imaging regions of adjacent cameras overlap each other, wherein at least two, In particular, image data captured by all cameras in the central imaging areas can be calculated into a common image.

The method of optically inspecting the rod-shaped articles has the same or similar advantages as previously mentioned with respect to the device, so that repetition is omitted shall be.

In particular, it is provided that the image acquisition takes place with the aid of cameras which comprise a two-dimensional image sensor. It is further provided, in particular, that the detection of the images of the rod-shaped article takes place without a further optical element being located in the beam path, such as, for example, one or more prisms or a mirror. In other words, the cameras capture directly through their entocentric lenses the rod-shaped article.

According to an advantageous embodiment, it is provided that at least one intermediate space between two adjacent segments and / or at least one length of a segment of the rod-shaped articles is measured quantitatively.

It is also provided that the method is also used to qualitatively examine the rod-shaped articles or the segments, for example with regard to a quality of the cut edges.

It is further provided, in particular, that a width of one of the intermediate spaces and / or a length of a segment oriented in the longitudinal extension direction of the receiving trough, in particular with an accuracy of better than 0.1 mm, is / is measured. Advantageously, the method allows a very accurate measurement of the width of the spaces between the individual segments.

It is further provided, in particular, that the cameras are calibrated by evaluating the image data of adjacent cameras acquired in the overlapping central image areas and determining a shift vector between the imaging areas of adjacent cameras.

The method is further developed, in particular, in that the rod-shaped articles during the transverse-axial promotion on a conveyor drum be recorded.

The object is further achieved by a method for controlling and / or regulating a rolling device in an arrangement of the tobacco processing industry. The arrangement comprises an apparatus for optically inspecting rod-shaped articles according to one or more of the aforementioned embodiments, and a rolling device. In the rolling device, the composition of segments is covered with a leaflet. The rod-shaped articles of the tobacco processing industry are tested according to a method of optically inspecting rod-shaped articles of the tobacco-processing industry according to one or more of the aforementioned embodiments. This test takes place with respect to a conveying direction of the rod-shaped articles, upstream of the rolling device.

The rolling device comprises, for example, a conveyor drum on which the rod-shaped articles are conveyed transaxially and with which the rod-shaped articles are fed to a roller block. The test is done, for example, while the composition of the segments is located directly on the conveyor drum, just before the compilation is rolled into a leaflet.

• einem Vorhandensein eines oder mehrerer Segmente,
• einer Anzahl der in der Zusammenstellung vorhandenen Segmente,
• einer Lage und/oder Art der Segmente, wobei unter der Art eines Segments beispielsweise dessen Typ und Dimension zu verstehen ist,
• einer Größe zumindest einer Lücke zwischen zwei benachbarten Segmenten,
• einer Größe einer Länge zumindest eines Segments und/oder
• einem Vorhandensein und/oder einer Lage eines Blättchens, welches

According to further aspects, it is provided that a parameter set is obtained during the optical testing of the rod-shaped articles, which describes in particular completely the composition of several segments. For example, this parameter set includes information about:

• a presence of one or more segments,
• a number of segments present in the compilation,
• a position and / or type of segments, the type of segment being understood, for example, as its type and dimension,
• a size of at least one gap between two adjacent segments,
• a size of a length of at least one segment and / or
• a presence and / or location of a leaflet which

is provided for wrapping the composition of the segments in a rolling device.

On the basis of this parameter set, for example, a process control and / or regulation is performed. For example, an association between a rod-shaped article and a parameter set can be made. If a rod-shaped article does not fulfill a predefined quality criterion due to a deviation of one or more parameters from a predetermined desired value, then this rod-shaped article may be ejected after the rolling process and excluded from further processing. It is further provided in particular that the parameter set or individual values / parameters are used to follow-up and / or to control the process of assembling the segments. If, for example, a too small gap is detected between segments, this information can be used to readjust the composition so that the desired setpoint value is maintained in the subsequent compilations. Furthermore, it is provided in particular that the parameter set is used in the context of quality control for the detection of sources of error. For example, faulty base materials can be identified.

Further features of the invention will become apparent from the description of embodiments according to the invention together with the claims and the accompanying drawings. Embodiments of the invention may satisfy individual features or a combination of several features.

FIG. 1

schematisch und vereinfacht einen Aufbau gemäß dem Stand der Technik, mit dem eine optische Abbildung eines stabförmigen Artikels aus einer Zusammenstellung aus mehreren Segmenten mit einem entozentrischen Objektiv durchführbar ist,

FIG. 2

ein mit einer Anordnung aus FIG. 1 erhaltenes Bild,

FIG. 3

eine Kameraanordnung mit einer Mehrzahl von Kameras zur Bilderfassung eines stabförmigen Artikels aus einer Zusammenstellung aus mehreren Segmenten in einer Vorrichtung der Tabak verarbeitenden Industrie

FIG. 4

ein Bildfeld einer ersten und einer zweiten Kamera der Kameraanordnung,

FIG. 5

zueinander korrigierte Bildfelder der ersten und der zweiten Kamera der Kameraanordnung,

FIG. 6a

ein mit dieser Kameraanordnung erhaltenes Bild, welches von einer Verarbeitungseinheit errechnet wurde aus den Bilddaten der einzelnen Bilder der Kameras der Kameraanordnung

FIG. 6b

im Vergleich dazu das bereits aus FIG. 2 bekannte Bild und

FIG. 7

eine Vorrichtung der Tabak verarbeitenden Industrie zum optischen Prüfen von stabförmigen Artikeln der Tabak verarbeitenden Industrie, wobei die Vorrichtung eine Fördertrommel zur queraxialen Förderung der stabförmigen Artikel umfasst, die Fördertrommel eine Vielzahl von Aufnahmemulden umfasst, in denen die stabförmigen Artikel aufgenommen sind und ferner eine Bilderfassungsvorrichtung umfasst ist, mit der die in den Aufnahmemulden angeordneten stabförmigen Artikel während der queraxialen Förderung erfasst werden.

The invention will be described below without limiting the general inventive idea by means of embodiments with reference to the drawings, reference being expressly made to the drawings with respect to all in the text unspecified details of the invention. Show it:

FIG. 1

schematically and simplifies a structure according to the prior art, with which an optical image of a rod-shaped article from a combination of several segments with an entocentric lens is feasible,

FIG. 2

one with an arrangement FIG. 1 preserved picture,

FIG. 3

a camera assembly comprising a plurality of cameras for imaging a rod-shaped article from a composite of multiple segments in a device of the tobacco processing industry

FIG. 4

an image field of a first and a second camera of the camera arrangement,

FIG. 5

mutually corrected image fields of the first and the second camera of the camera arrangement,

FIG. 6a

an image obtained with this camera arrangement, which was calculated by a processing unit from the image data of the individual images of the cameras of the camera arrangement

FIG. 6b

in comparison to that already out FIG. 2 well-known picture and

FIG. 7

an apparatus of the tobacco processing industry for optically inspecting rod-shaped articles of the tobacco processing industry, the apparatus comprising a conveyor drum for transversely conveying the rod-shaped articles, the conveyor drum comprising a plurality of receiving wells in which the rod-shaped articles are received and further comprising an image capture device is with which the arranged in the receiving troughs rod-shaped articles are detected during the cross-axial promotion.

In the drawings, the same or similar elements and / or parts are provided with the same reference numerals, so that apart from a new idea each.

Fig. 1 Fig. 12 schematically and simplified shows a prior art optical structure for imaging a rod-shaped article 2 with an entocentric or nearly entocentric objective 4. For simplicity, the entocentric objective 4 is represented by a single lens. The rod-shaped article 2 is an assembly of several segments 6a, 6b, 6c, 6d and 6e. The entocentric lens 4 detects the objects in the object space at an opening angle α. The outer light rays in this angular range are incident obliquely into the entrance lens of the objective 4. This results in that the outer segments 6a, 6b and 6d and 6e, especially the two outer segments 6a and 6e are not viewed directly from above, ie from a viewing direction perpendicular to a Längsaxialrichtung L (shown in dotted line).

Fig. 2 shows by way of example and simplifies the resulting image of the rod-shaped article in FIG Fig. 1 known arrangement. The images of the segments 6a..6e are denoted by 8a..8e. Apart from the central segment 6c (see reference numeral 8c), all segments 8a..8e are shown with at least partial views of the end faces 10 facing inwards, ie in the direction of the center of the rod-shaped article 2. This circumstance results in that the edges 12 of the segments 6a..6e of the rod-shaped article 2, which in the idealized schematic representation of Fig. 2 are shown by a solid line, can not be detected with sufficient separation. So it's using an entocentric optic 4, as exemplified in Fig. 1 is shown, only with significant reductions in terms of achievable accuracy possible to measure the distances D1 to D4 between the segments 6a..6e exactly. While distances D2 and D3 may still be accurately detected to a reasonable extent, this is clearly no longer the case for distances D1 and D4. Furthermore, it is not possible to get a quality of To detect edges 12 with sufficient accuracy.

A remedy here is the device according to aspects of the invention, the various embodiments of which will be described below. The device comprises a conveying member which is later associated with Fig. 7 is explained in more detail. Furthermore, the device comprises an image acquisition device, with which the rod-shaped articles 2 can be detected or detected on the conveying member during the transverse axial conveyance.

The image capture device comprises a camera assembly 14 as schematically and simplified in FIG Fig. 3 is shown. The camera assembly 14 includes a plurality of cameras 16a, 16b, 16c, 16d and 16e. Each of the cameras 16a..16e is provided with an entocentric objective 4a..4e. The cameras 16a..16e of the camera assembly 14 together with their associated entocentric lenses 4a..4e form the image capture device 18. The image capture device 18 further comprises means, such as a suitable control or regulation, which ensures that the cameras 16a..16e of Camera assembly 14 are synchronized. In other words, the cameras 16a..16e are triggered at the same time, thus capturing image data at the same time.

The image acquisition device 18 is adapted to rod-shaped article 2, which are arranged in receiving troughs of a conveying member, for example a conveyor drum, to detect during their transverse axial promotion. The individual cameras 16a, 16e of the camera arrangement 14 are arranged next to one another in a direction of longitudinal extent of the receiving troughs of this conveying member. This longitudinal direction A is in Fig. 3 indicated by a dotted line (cf. Fig. 7 ).

The objectives 4a..4e of the cameras 16a..16e of the camera arrangement 14 are entocentric optics or approximately entocentric optics. For the sake of simplicity, the entocentric lenses are 4a..4e each represented by a single lens. Each lens 4a..4e detects an object field and images it onto the sensor of the associated camera 16a..16e. Shown are the viewing angles of the cameras 16a..16e with their respective opening angle α1, α2, α3, α4 and α5. The opening angles α1..α5 are at least approximately the same size. Light incident from the aperture angles α1..α5 in the lenses 4a..4e is imaged onto a central imaging region of the sensors of the cameras 16a..16e. The opening angles α1..α5 of the entocentric lenses 4a..4e of the camera arrangement 14 are all small compared to the opening angle α of the in Fig. 1 shown entocentric lens 4 according to the prior art. The opening angles α1..α5 of the entocentric lenses 4a..4e overlap each other in the object space. This overlap area in the object space should be designated by reference numeral 26 '. Light incident from the overlapping area 26 'is picked up by two cameras 16a, 16e, for example from the two adjacent cameras 16a and 16b, and imaged in each case in a central imaging area 22a, 22b. The rod-shaped article 2 passes through the object field during the transverse-axial conveyance and is detected by the cameras 16a..16e.

Fig. 4 shows by way of example an image field 20a of the first camera 16a as it is imaged onto an area sensor, for example a CMOS sensor, of this camera by the associated objective 4a. Further, the image field 20b of the second camera 16b of the camera assembly 14 is shown. Each of the image fields 20a, 20b comprises a central imaging region 22a, 22b. Light incident from the object space at the angle α1 into the objective 4a of the first camera 16a is imaged into the central imaging area 22a. This also applies analogously to the other cameras 16b..16e. The respective central imaging regions in the object space should be designated by the reference symbols 22a 'to 22e'. In these areas, the associated lenses 4a, 4b form distortion-free or virtually distortion-free. At least the distortion of the associated objective 4a, 4b is below a predetermined limit value. For example, this is given as a percentage of the ideal figure. This limit value is, for example, less than 1%, in particular less than 2%, furthermore in particular less than 2.5% and furthermore in particular less than 5%, furthermore the imaging error is less than 7.5%, furthermore in particular less than 10%. and more particularly less than 15%.

The central imaging region 22a, 22b is surrounded by an imaging edge region 24a, 24b in which the distortion is greater than in the central imaging region 22a, 22b. In particular, the distortion in the imaging edge area 24a, 24b is above one of the aforementioned limit values. The cameras 16a, 16e of the camera arrangement 14 are arranged such that the central imaging areas 22a, 22b of adjacent cameras 16a, 16e overlap one another. The overlapping area 26 is the intersection between the adjacent central imaging areas 22a, 22b of adjacent cameras 16a, 16e.

There is provided in the image capture device 18 a processing unit which is adapted to calibrate the cameras 16a..16e of the camera assembly 14 by evaluating the image data of adjacent cameras 16a..16e acquired in the overlapping central image regions 22a, 22b. For example, cross-correlation between the image data of the images of adjacent cameras in the overlapping area 26 is calculated. By means of such a comparison, a displacement vector 28 can be calculated by which the image fields 20a, 20b of the adjacent cameras 16a, 16b are shifted from one another. In the in Fig. 4 illustrated embodiment, the displacement vector 28 is directed exclusively vertically. If the overlap region 26 is wider than desired or narrower than desired, then the displacement vector 28 would additionally comprise a corresponding horizontal component. A shift vector 28 is calculated for all adjacent cameras 16a, 16e of the camera arrangement 14.

The processing unit is now set up by the cameras 16a, 16e of the camera arrangement 14 in the central imaging areas 22a, 22b recorded image data to a common image of the camera assembly 14 to charge.

Fig. 5 2 shows the two image fields 20a, 20b corrected by the shift vector 28, for example the cameras 16a and 16, wherein the image field 20b of the second camera 16b is shown with a dashed line for clarification. The two central receiving areas 22a, 22b are joined together, it being possible in the overlapping area 26 optionally to use the image data of one or the other camera.

By appropriate application of the mechanism described above can be from the individual image fields 20a to 20e, as shown in Fig. 3 are shown schematically and simplified, win a complete picture of the rod-shaped article 2. Deviating from the actual execution are in Fig. 3 the image fields 20a..20e, and this only for reasons of clarity, not shown overlapping.

As a result of this measurement, an image of the rod-shaped article 2 can be provided as it is Fig. 6a shows an example and schematically simplified. Directly below is in Fig. 6b that already out Fig. 2 known image of the rod-shaped article 2, as it can be obtained with a single entocentric lens 4. Advantageously, the device according to aspects of the invention provides an image of the rod-shaped article 2, in which both the edges 12, of which only a few are provided with reference numerals for reasons of clarity, are clearly and clearly visible. Consequently, the distances D1..D4 between the individual segments 6a... 6e can be determined very accurately by determining them with the knowledge of the magnification of the objectives 4a..4e from the distances D1 '.. D4' between the images 8a..8e the corresponding segments 6a..6e be calculated.

In other words, the device is set up in such a way that intermediate spaces 30 (cf. Fig. 3 of which, for reasons of clarity, only a few are provided with reference numerals) between adjacent ones Segments 6a..6e the rod-shaped article 2 can be measured quantitatively. The same applies to a length of the segments 6a..6e.

The image acquisition device 18 is further particularly adapted to measure the distances D1..D4 between the segments 6a..6e with an accuracy better than 0.1 mm. For this purpose, in particular depending on the recording distance B (object width), as in Fig. 3 is indicated, a resolution of the lenses 4a..4e and a resolution of the sensors used in the cameras 16a..16e (number of pixels or pixels per unit length) chosen so that the desired resolution is achieved.

Fig. 7 shows a device 32 of the tobacco processing industry for optical testing of rod-shaped articles 2, wherein the rod-shaped article 2 for reasons of simplicity in Fig. 7 not shown as a collection of multiple segments. The device 32 comprises as a conveying member a conveying drum 34, which is shown in sections. On a surface of the conveyor drum 34 are receiving troughs 36, in which the rod-shaped article 2 are received during their transverse axial promotion in a conveying direction R. The conveying direction R corresponds to a direction of rotation of the conveyor drum. Above the receiving troughs 36 is the image capture device 18 already described above, of which only a few camera units, each comprising a camera and an entocentric lens, are shown schematically in an exemplary representation. The receiving wells 36 have a longitudinal direction A, which already in connection with Fig. 3 was mentioned and in Fig. 7 also indicated by dotted line. The longitudinal extension direction A is oriented at least approximately perpendicular to the conveying direction R. The individual cameras 16a, 16e of the camera arrangement 14 of the image acquisition device 18 are arranged next to one another in this longitudinal direction A. Thus, it is possible to optically inspect the rod-shaped articles 2 during the transverse-axial conveying on the conveying member 34.

The device 32 further comprises a processing unit 38, for example a computer, a workstation or the like, which is, inter alia, set up to control and read out the image capture device 18, to carry out the mentioned calibration and to calculate the common image of the camera arrangement 14.

All mentioned features, including the drawings alone to be taken as well as individual features that are disclosed in combination with other features are considered alone and in combination as essential to the invention. Embodiments of the invention may be accomplished by individual features or a combination of several features. In the context of the invention, features which are identified by "particular" or "preferably" are to be understood as optional features.

LIST OF REFERENCE NUMBERS

2

rod-shaped article

4, 4a..4e

entocentric lens

6a..6e

segment

8a..8e

images

10

front

12

cut edges

14

camera assembly

16a..16e

camera

18

Image capture device

20a, 20b

field

22a, 22b, 22a '.. 22e'

central picture area

24a, 24b

Picture edge region

26, 26 '

overlap area

28

displacement vector

30

interspaces

32

Device of the tobacco processing industry

34

conveying member

36

receiving troughs

38

processing unit

α, α1..α5

opening angle

L

longitudinal axial

D1..D4, D1 '.. D4'

distance

A

Longitudinal extension

R

conveying direction

Claims (11)

A tobacco processing apparatus (32) for optically inspecting rod-shaped articles (2) of the tobacco processing industry, the rod-shaped articles (2) each being an assembly of a plurality of segments (6a..6e), and wherein the device (32) a conveying member (34) for transversely conveying the rod-shaped articles (2) and the conveying member (34) comprises a plurality of receiving troughs (36) in which the rod-shaped articles (2) are receivable or received, wherein the device (32) further comprising an image capture device (18) with which the rod-shaped articles (2) arranged in the receiving troughs (36) can be detected or detected during the cross-axial conveyance, characterized in that the image capture device (18) comprises a camera arrangement (14) with a plurality of cameras (16a..16e) for image capture, wherein the cameras (16a..16e) are synchronized in particular for simultaneous image capture u nd wherein these cameras (16a..16e) in a longitudinal direction (A) of the receiving wells (36) are arranged side by side, and wherein each camera (16a..16e) of the camera assembly (14) comprises an entocentric or at least approximately entocentric objective (4a..4e) and with this an object field, which run through the in the receiving troughs (36) arranged rod-shaped article (2) during the transverse axial promotion, on a field of view (20a, 20b ), wherein the image field (20a, 20b) comprises a central imaging region (22a, 22b) in which the objective (4a..4e) images without distortion, or at least with a distortion below a predetermined or predefinable limit, which is dependent on an imaging Surrounding area (24a, 24b) is surrounded with greater distortion, wherein the cameras (16a..16e) are arranged in the camera assembly (14) such that the central imaging regions (22a, 22b) of adjacent cameras (16a..16e) overlap each other wherein the image capture device (18) further comprises a processing unit (38) adapted to receive from at least two, in particular all, cameras (16a..16e) of the camera assembly (14) image data captured in the central imaging regions (22a, 22b) to a common image of the camera assembly (14). The apparatus (32) of the tobacco processing industry according to claim 1, characterized in that the processing unit (38) is further adapted to at least one gap (30) between two adjacent segments (6a..6e) and / or at least one length of a segment (6a..6e) of the rod-shaped article (2) to measure quantitatively. Device (32) of the tobacco processing industry according to claim 2, characterized in that the image acquisition device (18) and the processing unit (38) are further adapted to at least one in the longitudinal direction (A) of the receiving wells (36) oriented distance (D1 .. D4) between two adjacent segments (6a..6e) and / or a length of a segment (6a..6e) oriented in this longitudinal extension direction (A), in particular with an accuracy of better than 0.1 mm. The apparatus (32) of the tobacco processing industry according to any one of claims 1 to 3, characterized in that the processing unit (38) is further adapted to calibrate the cameras (16a..16e) of the camera assembly (14) by placing in the evaluated overlapping central image areas (22a, 22b) image data of adjacent cameras (16a..16b) are evaluated and a shift vector (28) between the image fields (20a, 20b) of adjacent cameras (16a..16e) is determined. Device (32) of the tobacco processing industry according to one of claims 1 to 4, characterized in that the conveying member (34) is a conveyor drum. Arrangement of the tobacco processing industry, comprising a device according to one of claims 1 to 5 and a rolling device, wherein the device for optically testing rod-shaped articles (2) with respect to a conveying direction of the rod-shaped article (2) is arranged upstream of the rolling device. Method for optically testing rod-shaped articles (2) of the tobacco-processing industry, wherein the rod-shaped articles (2) are each an assembly of several segments (6a..6e) and are conveyed transaxially by a conveying member in a receiving trough (36) of the conveying member , characterized in that the rod-shaped articles (2) during the transverse-axial promotion with a plurality of cameras (16a..16e) are detected, the cameras (16a..16e) are in particular synchronized and the rod-shaped article (2) in particular simultaneously and wherein these cameras (16a..16e) are arranged side by side in a direction of longitudinal extent (A) of the receiving trough (36), and wherein each camera (16a..16e) entocentrically or at least an object field partially comprising the rod-shaped articles (2) The image field (20a, 20b) comprises a central imaging region (22a, 22b) in which a lens (4) of the camera (16a..16e) is free from distortion or at least one Imaging below a predetermined or predeterminable limit surrounded by an imaging edge region (24a, 24b) with greater distortion, and wherein the rod-shaped article (2) is imaged such that the central imaging regions (22a, 22b) of adjacent cameras ( 16a..16e) overlap one another, wherein the image data captured by at least two, in particular by all, cameras (16a..16e) in the central imaging regions (22a, 22b) are calculated into a common image. A method according to claim 7, characterized in that at least one intermediate space (30) between two adjacent segments (6a..6e) and / or at least one length of a segment (6a..6e) of the rod-shaped article (2) is measured quantitatively / is , A method according to claim 8, characterized in that in the longitudinal direction (A) of the receiving trough (36) oriented width of a gap (30) and / or in the longitudinal direction (A) oriented length of a segment (6a..6e), in particular with an accuracy of better than 0.1 mm, is / will be measured. Method according to one of claims 7 to 9, characterized in that the cameras (16a..16e) are calibrated by the in the overlapping central image areas (22a, 22b) detected image data of adjacent cameras (16a..16e) evaluated and a Shifting vector (28) between the imaging regions (22a, 22b) of adjacent cameras (16) is determined. Method according to one of claims 7 to 10, characterized that the rod-shaped articles (2) are detected during the cross-axial promotion on a conveyor drum.

Images