DE4312550C1 - Device for assessing moving objects - Google Patents

Abstract

A device for assessing moving objects (13) comprises an illumination device (31), which is equipped for the purpose of generating a first intensity distribution (J1) of light in a first measurement plane (37) and a second intensity distribution (J2) of light in a second measurement plane (38), the respective object (13), when passing through the measurement planes (37, 38), influencing these intensity distributions (J1, J2) in a measurable way. In addition, provision is made of a detector apparatus (32), which is equipped for the purpose of registering the influences of the first and of the second intensity distribution (J1, J2) along a first measurement coordinate (48) and a second measurement coordinate (49). Furthermore, an evaluation device is provided which derives at least one control signal from the registered influencing of the intensity distributions (J1, J2), the said control signal containing an assessment of the respective object (13) (Fig. 2). <IMAGE>

Description

The present invention relates to a control device lieren and / or differentiate falling objects, preferably of free-falling tablets.  

The pharmaceutical industry is moving more and more to tablets no longer in blister packs, but conventional again in pill tubes. That turns it Problem, like tablets in number and quality in the bottles are to be brought in.

So far, this has been done in such a way that moldings are part of the wells to be filled into tablets by a "swamp" from tablets, with one in each well Tablet deposits. These strips are then placed over filling funnels emptied under which the tubes to be filled pass. On the one hand, this method has the disadvantage that it is inaccurate, and on the other hand that the tablets during the Filling cannot be checked for breakage at the same time can.

However, it is already known to count and to Use break detection, use the cameras and the Monitor tablets as they are filled into the tubes. However, these devices have several disadvantages:

First, they need an image memory, which is a complex Hardware requires. On the other hand, first of all the image memory must be written in full before the evaluation can take place, these conventional systems are very slow in their resolution is also limited. Finally, since all cameras fig optics require spherical aberrations distorting and limiting accuracy based on the evaluation. In addition, with camera systems there are considerable space requirements connected.  

A device known from document DE-U-91 14 260 is used for this purpose, tablets inserted in blister packs check for breakage. For this purpose the Blisterver packs before applying the lidding film on an LED line moved past, which creates a kind of light curtain. In the several tracks side by side disrupt tablets when passing through this light curtain its intensity ver division, what of a line sensor either in reflected light or is detected by transmitted light.

The LED line and the line sensor are clocked so that a row as the blister packs move past of sectional images of the one formed by the light curtain Tablets crossing the measuring plane are generated. Furthermore, detects the feed speed of the blister packs, so that the line sensor the dimensions of the known Tablets in the longitudinal direction of the line sensor - i.e. in one Measurement coordinate - reproduces. From the course of time of the so The intensity distribution measured is then, as it were, an evaluator tion criterion the area of the tablet across this measurement plane calculated. Based on this assessment, a control signal is generated generated, which indicates whether the tablet is error-free or not.

If the calculated area falls below a reference value, then an error is issued, i. H. the tablet is broken as or marked incorrectly. This will make the reference value determines that first a blister pack with "good" Tablets is read.  

To avoid the influence of extraneous light, an infrared LED Line used. Accordingly, the line sensor is on Infrared filter upstream. To get a sharp picture of the getting individual cuts through the tablets is between the infrared filter and the line sensor an imaging optics in the form of a row of cylindrical lenses - so-called SELFOC- Lentils - arranged.

Regarding the tablets sold in blister packs are the disadvantages of the methods mentioned above already eliminated. The line sensor is used for each cut read out serially and on-line by means of a comparator decided whether the pixel currently being read is a Tablet or not. Assign that to a tablet Pixels are assigned to the respective via a data selector Counters for the corresponding column are fed in and counted there. The number of all pixels for a given tablet have been determined, then with a previously read Reference value compared.

This arrangement therefore has the advantage that on the one hand complex hardware of known camera systems can be dispensed with can and that on the other hand the evaluation takes place on-line.

Another device for checking in blisterver packs of inserted tablets is described in U.S. Patent No. 4,847,487 described. Every possible tablet position is there Light transmitter and a light receiver in the form of a phototransistor  assigned. The geometric arrangement is such that a complete tablet the phototransistor completely darkens. If the tablet has errors that are in your Make the cross-section noticeable, depending on its size, Error more or less light to the phototransistor that recognizes that a faulty tablet has been inserted. Based on the intensity of the incident light, the Phototransistor also detect if a partial error stuck tablet or if the tablet is missing completely. Based on this result, the known device enters Control signal from the entire blister pack checked rejects, i.e. excludes from further processing.

Furthermore, it is known from utility model DE-U-73 21 096 To use light barriers in packaging machines. The Light barriers control two-armed levers here Absence of an object in the relevant path of the Packing machine get in the way of the light barrier.

Based on this state of the art, it is the task of present invention to provide a device with which Controlling objects falling with simple design effort and can be qualified. In particular, it should be able to evaluate freely falling objects.

With regard to the device mentioned at the beginning, this is Problem solved in that the following features are provided:

• a lighting device which is set up to a first intensity distribution in a first measurement plane of light that the object in question Traversing the first measurement level, and influenced in a second measuring plane different from the first measuring plane to generate a second intensity distribution of light which the respective object when crossing the second Measuring level influenced,
• a detector device which is set up to Influencing in successive cuts the first intensity distribution along a first Measurement coordinate and influencing the second intensity distribution along one of the first measurement coordinates various second measurement coordinates in transmitted light or To measure incident light methods so that the respective dimensions of the object in the direction of respective measurement coordinates are recorded, and
• - An evaluation device, which from the detected dimensions derives at least one control signal that qualifies of the respective object, whereby
• - A resettable sorting station depending on the objects forwarded differently from the control signal.

The object on which the invention is based is achieved in this way completely solved. The fact that in two different from each other Measuring coordinates influencing various intensity ver Divisions measured by the object can namely be  Statements about the quality of what falls through the measurement levels Win object. The objects are valued, so to speak in two different views what the review option clearly increased. While it is in the known devices was only possible, so to speak, to the "floor plan" of the objects check so that it is only visible from the side Errors were not taken into account, there is an "all around evaluation "of the objects. With this device it is now also possible to check and distinguish objects, their exact Alignment in space is not known.

In this way it is not only possible to break tablets To investigate, you can also use different types of tablets be distinguished from each other.

The evaluation of the respective object can either be one Comparison with a reference object may include, however also be possible to contour the object capture, so that such errors can be recognized that compensate in the area itself. I.e. so that also a partly too small or partly too large, The sum of the detected surface elements is not an error is recognized, can nevertheless be assessed as faulty here.

Another advantage is that because of the resettable sorting station the objects depending on the result of the evaluation either can be eliminated or further processed. Here can also distinguish between different  Objects can be provided. So it is z. B. possible with the new Device different types of tablets at the same time both to check as well in different tubes or in forward different numbers in common tubes.

In particular, it may be necessary to ensure that the objects at least when crossing the measurement planes Maintain alignment across your direction of movement. On this way it is excluded that tumbling objects become one falsify the measurement result.

As before, the new device can either be or operated in transmitted light.

If the first and second measurement coordinates in the first and second measurement level, this has the advantage that immediately can be worked in transmitted light, which in particular is desired for adjustment reasons.

It is further preferred if the first and the second measurement line dinate run approximately perpendicular to each other. Constructive conditionally, this angle can deviate from 90 ° because z. B. the geo metry 90 ° or mounting tolerances to inaccuracies to lead.

The advantage here is that the object, so to speak, from the front and viewed from the side, so that comprehensive information can be obtained about his condition.

It is further preferred if the detector device has a Line sensor with in the direction of the respective measurement coordinate optical sensors arranged side by side comprises.  

This measure has the advantage that during the passage of the object through the measuring plane all the sensors simultaneously Record intensity distribution, it is not necessary in the measurement coordinate in a mechanical or other way to feel. For example, a CCD line can be used here become.

It is further preferred if the first and the second Measuring plane run parallel to each other or preferably in are on the same spatial level.

The advantage here is that no geometric distortions or the like. are calculated from the measured intensity distributions have to. Because the distances at which the cuts from the objects be taken from the speed of passage of the objects depend on the respective measuring level, result in particular simple relationships when the measurement planes are parallel to each other because then the passage speeds are for both measurement levels are the same.

If the two measurement planes are in one spatial plane, has the further advantage that the height of the new front direction in the direction of movement of the objects is kept very low becomes. This is another advantage over the known ones Camera systems that have larger dimensions. Are they lying Measuring planes, however, are somewhat offset in the direction of movement of the objects to each other, so the advantage of the low height compared to conventional camera systems pregnant, while there is the further advantage that the  Intensity distributions do not interfere with the detectors of the other measuring level. This is already done by a rectangular arrangement of the line sensors promoted, but a additional offset brings further "optical isolation" of the Measuring planes against each other.

It is further preferred if the detector device has a Imaging device which includes the intensity distribution maps to the sensors.

The advantage here is that the imaging device for a high luminous efficiency is ensured. In addition, the Illustration of a very sharp section through the respective Object, causing distortions such as those found in camera systems diving can be avoided here.

In a preferred development, the mapping includes direction at least one imaging light guide arrangement.

This measure is particularly advantageous that the Detector device itself not directly to the possibly falling Object must be brought up. Rather, they can imaging light guide arrangements take over which the the intensity distribution shown is distortion-free to the Forward detector device. Because the detector devices can usually be provided with additional electronics a very compact, small measuring arrangement made of lighting pre Direction and light guide arrangement are built up, the tight can be brought up to the objects to be checked. In order to all distortion errors are eliminated, which are caused by large Imaging optics can be effected.  

It is further preferred if the lighting device has at least one infrared light source and if the Imaging device includes an infrared filter.

This measure has the advantage already discussed above that namely the influence of extraneous light is eliminated. Be here mentions that these advantages are shared with other optical Let wavelengths be achieved. It just has to be ensured be that little or no on the wavelength used Extraneous light prevails in the area of the new device.

It is further preferred if the lighting device is in the respective measuring plane, arranged in a row Includes light transmitter.

The advantage here is that the intensity distribution in the Measuring level is built up stationary, so to speak. This light transmitter can either be an LED line or also a possibly also imaging light guide.

Furthermore, it is preferred here if an arrangement is provided is which is set up to determine with which Objects move in the area of the measuring planes move.

This measure has the advantage that influences on the movement speed of the objects can be calculated, so to speak nen. This is also an advantage for freely falling objects, because differs due to the disruptive effects of air resistance the falling speed of objects of different weights from each other. If this effect were not taken into account, fewer objects falling per unit length  Cross-sectional images are taken as of slower falling objects If, on the other hand, you still use a con distance between the sectional images on the objects, so would objects falling faster than "too small", so to speak.

In a further development it is preferred if the device is a Counter station is assigned, which the control signal as a count impulse used.

The advantage here is that the control signal, based on the "good" and "bad" objects are distinguished, at the same time is used to count the good objects. In this way can e.g. B. the number of tablets can be recorded that already were placed in a tube to be filled.

Overall, it is preferred if the evaluation device at least one comparison with at least one reference signal performs and the control signal depending on the comparison generated.

The advantage here is that no complex and, so to speak, absolute Evaluation criteria are required, in the form of a YES / NO Rather, decision can be made easily and quickly it is decided whether the object to be examined is the Evaluation criterion met or not.

An embodiment of the invention is in the drawing shown and is described in more detail in the following description explained. Show it:

Fig. 1 is a filling station for tablets, in which the novel apparatus is used;

Fig. 2 is a plan view of the measuring station of the new device, along the line II-II of Fig. 1;

Fig. 3 is successively measured intensity distributions for a falling tablet, measured in two perpendicular zueinan of measuring coordinates;

Fig. 4 is a side view of the measuring station of the new device, along the line IV-IV of Fig. 2;

Figure 5 is a schematically illustrated arrangement for determining the speed of fall of the tablets of FIG. 1.

FIG. 6 shows, in a representation like FIG. 2, a measuring station in which the imaging device uses optical fibers; and

Fig. 7 is a block diagram of the evaluation device for the new apparatus in FIG. 1.

A filling station 10 for objects 12 , which in this case are tablets 13 , is shown schematically in a side view in FIG. 1. The tablets 13 are placed in a chute 14 , where they move downwards in the direction of movement 15 , that is to say fall.

On their way through the chute 14 , the tablets 13 pass through a device 17 for evaluating the objects. The device 17 comprises a measuring station 18 to be explained in more detail as well as an evaluation device 19 which is connected to the measuring station via lines 20 .

A sorting station 21 is also provided, which either directs the incoming tablets 13 via a shaft 22 into a collecting container 23 for broken tablets 13 a, 13 b, or the tablets 13 c via a filling shaft 24 in tablet tubes 25 a, 25 b, 25 c filled. In the exemplary embodiment shown, the tablet tube 25 a is already completely filled with tablets, while the tablet tube 25 b is being filled.

The sorting station 21 comprises a flap 27 , which is actuated by a control signal S1, which is generated by the evaluation station 19 and contains an evaluation of the objects 12 . Depending on the position of the flap 27 , the tablets 13 either get into the collecting container 23 or into a tablet tube 25 . The evaluation device 19 outputs a second control signal 52 , which reproduces the number of tablets 13 guided into the filling shaft 24 . This control signal S2 is used to move the tablet tubes 25 further in the direction of their transport direction 28 when the predetermined number of tablets has been entered into the current tablet tube.

The device 17 thus serves on the one hand to sort out defective tablets 13 or tablets 13 that are not to be used for other reasons. On the other hand, it also serves to fill a predetermined number of "good" tablets into each tablet tube 25 .

The filling station 10 can be expanded in such a way that further sorting stations 21 are connected downstream of the filling shaft 24 , so that different types of tablets can be checked and evaluated simultaneously by the device 17 . In addition to the GOOD / BAD decision, the assessment then includes a further qualification with regard to the tablet type. In this way, it is also possible to fill 25 tablets of different types into one and the same tablet tube.

FIG. 2 shows a plan view along the line II-II from FIG. 1 of the measuring station 18 .

It can be seen that the measuring station 18 comprises an illuminating device 31 and a detector device 32 , in the center of which a tablet 13 is indicated schematically. The lighting device 31 comprises a first infrared light source 33 in the form of an LED line 34 , and a second infrared light source 35 in the form of an LED line 36 . The LED line 34 generates an intensity distribution of infrared light in a first measurement plane 37 , while the LED line 36 produces a corresponding intensity distribution in a second measurement plane 38 . Arrows 39 and 40 indicate the directions of propagation of the intensity distributions emitted by LED lines 34 and 36 . It can be seen that the directions of propagation 39 and 40 are approximately perpendicular to one another.

A first line sensor 41 lies in the measurement plane 37 , while a second line sensor 42 lies in the measurement plane 38 . Each line sensor 41 , 42 has side-by-side optical sensors which respond to light of the wavelength as emitted by the LED lines 34 and 36 .

The intensity distributions in the measurement planes 37 and 38 are imaged on the line sensors 41 and 42 via imaging devices 43 and 44 . These imaging devices each include an infrared filter 45 and an array 46 of cylindrical lenses, so-called SELFOC lenses.

The arrangement is such that the light emitted by the LED lines 34 and 36 is focused directly on the line sensors 41 and 42 , the light of the first measuring plane 37 not influencing the second line sensor 42 and vice versa. This is due to the right-angled arrangement. If the measurement planes are in spatially offset planes, this optical isolation is further reinforced.

If a tablet 13 now passes across these measurement planes 37 and 38 , this leads to a kind of shadow formation on the line sensors 41 and 42 . As indicated in a coordinate cross 47 , the dimensions of the tablet 13 are then recorded in a first measurement coordinate 48 (line sensor 41 ) and a second measurement coordinate 49 (line sensor 42 ) perpendicular thereto. The intensity distributions detected by the line sensors 41 , 42 are given via lines 20 as I1 and I2 in the evaluation device 19 .

FIG. 3 shows two time diagrams 51 which show the intensity distributions which follow one another in time as a tablet 13 passes through the measurement planes 37 and 38 . To this end, it should first be noted that both the LED lines 34 and 36 and the line sensors 41 and 42 are clocked, that is to say they are controlled at a certain time interval in such a way that they build up and query an intensity distribution. In this way, there are successive de cuts through a tablet 13 falling through the measurement planes 37 , 38 . These intensity distributions 53 are therefore at a distance 54 from one another which, together with the falling speed of the tablet 13, determines the spatial position of the individual sections on the tablet 13 . As can be seen from the time diagrams 51 and 52 , the intensity distributions 53 lined up next to one another represent the view of the tablet 13 in the direction of the respective direction of propagation 39 , 40 . The dimensions of the tablet 13 can be calculated from these intensity distributions 53 in the direction of the respective measurement coordinate 48 , 49 by counting the individual sensors of the line sensors 41 and 42 , respectively, which are darkened by the tablet 13 . In the direction of movement of the tablet 13, however, ie in the direction of the time axis t, the dimensions are determined from the time intervals 54 and from the falling speed of the respective tablet. If one knows the distance corresponding to the time interval 54 , which the tablet has covered in this time interval, the time axis t can be transformed into a route axis and thus the area of the tablet 13 viewed from the direction of the propagation directions 39 in the manner of a support point integration. Calculate 40 .

Alternatively, it can also be provided that the contour of the tablet, as can be seen from the “silhouette” in FIG. 3, is evaluated directly. It could be the case that errors in the contour of the tablet are just averaging out with respect to the area of the tablet, but these errors should nevertheless be recorded.

Instead of a resolution of the tablet in the direction of the measurement coordinates, it is also possible to use a sum sensor in each measurement plane 37 , 38 , which measures the respective intensity distribution according to their sum. The shadow formation of a falling tablet 13 would then make this sum signal smaller, which can also be evaluated as a measure of the darkened area in the intensity distribution.

If the falling speed of the tablet 13 is always constant, no further measures are necessary, the time axis t is converted into a distance using a constant.

However, if tablets of different weights are sorted and should be evaluated, it results because of the disruptive Influence of air resistance may also be different Falling speed.

FIG. 4 shows a sectional illustration along the line IV-IV from FIG. 2, by means of which a possibility for determining the falling speed is illustrated.

In FIG. 4, it can be seen that the first measuring plane 37 and the second measuring plane 38 in the direction of movement 15 of the tablet 13 are off against each other. Although the two measurement planes 37 and 38 run parallel to one another, they are at a distance 55 from one another, which makes it possible to determine the falling speed. The time difference that lies between the immersion of the tablet 13 in the measuring plane 38 and the immersion in the measuring plane 37 determines the respective falling speed via the distance 55 .

In FIG. 5, a further arrangement 57 is shown, which the measuring planes 37, 38 upstream or downstream photoelectric sensors 58 and 59, the falling speed of the tablet 13 is determined by means of two in the direction of fall. The light barriers are arranged in the direction of movement 15 at a distance 60 from one another and each have a transmitter diode 61 and a receiver diode 62 . The time between the interruption of the first light barrier 58 and the second light barrier 58 here determines the falling speed via the distance 60 . Here, the two measurement planes 37 , 38 can then lie in the same spatial plane, so that it is ensured that the passage speed is identical for both measurement planes 37 , 38 .

In FIG. 6, in an arrangement like FIG. 2, a measuring station 18 is shown, in which the imaging devices 43 , 44 comprise optical fibers 64 , which are arranged between the arrays 46 and a line sensor 66 . These light guides transport the recorded intensity distribution without distortion to the line sensor 66 , which in the exemplary embodiment shown consists of five individual segments 67 . Instead of a line sensor 66, it is of course also possible to use an area sensor which is suitably illuminated by the light guides.

The use of such imaging light guides has the part before that the intensity distribution can be measured very close to the falling object, so that distortions are eliminated as far as possible. In addition, there is the further advantage that line sensors 66 can be used, the length (ie number of sensors times the mean distance of the sensors from one another) is not adapted to the measuring field (the individual measuring levels). Due to the imaging light guide 64 , it is also possible to effectively use such line sensors 66 . In the example shown in FIG. 6, the line sensor 66 has five segments 67 , as mentioned, of which, however, only two and a half segments are required for one case 14 . The other two and a half segments can be used for another chute. It should also be noted here that the assignment of segments and imaging light guides in FIG. 6 is chosen only as an example.

Each of these segments 67 outputs its own intensity distribution J1 *, J2 *, J3 *, J4 *, J5 *, but these intensity distributions J * do not correspond to the actually measured intensity distributions J1 and J2. How the conversion or reshaping takes place is now explained using the block diagram from FIG. 7.

As already mentioned, FIG. 7 shows a schematic block diagram of a part of the evaluation device 19 from FIG. 1.

The intensity distributions J1 * read out in series. . . J5 * are sent pixel by pixel to a comparator 71 for each segment 67 , where they are compared with a threshold value 72 (K). The threshold 72 is set so that disturbing noise effects are compensated for. The comparators 71 indicate at their output in the form of a yes / no decision whether the pixel in question is to be assigned to a tablet 13 or not.

All five comparators 71 feed into a multiplexer 73 , which distributes the individual pixels to the actually measured intensity - here z. B. J1 - assigns. At its output J1, the multiplexer 73 outputs all pixels of the segment J1 * and as many pixels of the segment J2 * as are covered by the light guide 64 depicting the left in FIG. 6. On a further output, not shown, the multiplexer 73 outputs all pixels that belong to the intensity distribution J2 and come from the segments J2 * and J3 *.

The intensity distribution J1 is also fed serially, ie pixel by pixel, to a counter 74 which counts up the number of pixels assigned to a tablet 13 in an intensity distribution J1. If a sum sensor is used, the counter 74 is of course unnecessary, since the sum sensor itself carries out the “summation”. If, on the other hand, the contour of the tablet 13 is to be evaluated, the counter 74 is likewise superfluous, because then the entire “length information” is evaluated.

After the number of pixels assigned to a tablet has been determined, this number is multiplied in a multiplier 75 by a factor F, which is supplied by a computing module 76 . The computing block 76 calculates from its input signals 77 , which, for. B. from the receiver diodes 62 from FIG. 5, the falling speed of the tablet 13 , and outputs a corresponding factor on its output line 78 . The resulting partial area value of the tablet 13 , which corresponds to the intensity distribution J1 at the time, for example t ₁ (see FIG. 3), is stored in a summer 80 . After a certain period of time, which can be determined by the falling speed, the next intensity distribution is compiled and processed as described above. The area value of the tablet 13 corresponding to the temporally subsequent intensity distribution is added to the previously calculated area value in the summer 80 . In a second adder 80 ', the area values of the tablet 13 , which result from the measurement in the second measurement plane 38 , are added up at the same time or with a time delay.

The summers 80 , 80 'are led with their outputs 81 , 82 to a computing circuit 84 , which combines the two summed values with one another and generates a comparison value V, which is given on an output 85 in a comparator 86 . In the comparator 86 , the comparison value V is compared with a reference value R, which is supplied via an output 87 of a read memory 88 .

This reference value R may either have been written into the read memory 88 from the outside, or may have been fed into the read memory 88 via a line 89 from the arithmetic circuit 84 during a “learning phase”. With this circuit it is possible to first drop a number of "good" tablets 13 through the chute 14 and to store the comparison values V determined in the process as "good values" in the read memory 88 for later use as a reference value. Exact knowledge of the geometry or the direction of the fall of the objects is not necessary, the new direction adapts automatically to the respective shape, so to speak. In the case of objects in particular, the orientation of which changes transversely to the direction of fall from object to object, a corresponding number of reference measurements ensures the required static safety for the reference value R.

In the internal calculation of the signals in the arithmetic circuit 64 , a reference signal supplied via a line 90 can also be taken into account, which contains a type of error evaluation criterion.

The comparator 86 now checks whether the comparison value V matches the reference value R within an error threshold Δ supplied via a line 91 . The result of this comparison is displayed on an output line 92 , which directly supplies the control signal 51 for the control of the sorting station 21 .

In a subsequent counting station 93, the "good" tablets 13 are counted so that each time information as is available, how many tablets have been entered b already in a just too filling tube of tablets 25th This information is made available via an output line 94 as control signal S2.

If only one type of tablet 13 is measured at a time, the speed constant automatically results when teaching. The reference value R in the read memory 88 , which is formed in exactly the same way as the comparison value V, then implicitly contains the falling speed, so to speak, so that the multiplier 75 and the arrangement 76 can be dispensed with. However, if you change the drop height of the tablet, it may be necessary to learn a new reference value.

The resolution that can be achieved with the device described so far is approximately 0.2 mm in the direction of fall and approximately 65 μm transverse to the direction of fall. While the resolution transverse to the direction of fall is caused by the distance between the sensors, the resolution in the fall direction results on the one hand from the falling speed of the tablets 13 and on the other hand due to the very high line repetition frequency of a line sensor compared to camera systems. The further advantage of a line sensor compared to a camera lies in addition to the higher spatial resolution in the line direction and the higher line repetition frequency, which means a higher resolution in the direction of the fall, and also in the smaller geometric dimensions, which leads to a reduced overall height. Particularly in the case of tablets with a very small diameter, the increased spatial resolution has great advantages over measuring devices working with camera systems.

In summary, the device for evaluating moving objects 13 comprises an illumination device 31 , which is set up to generate a first intensity distribution J1 of light in a first measurement plane 37 and a second intensity distribution J2 of light in a second measurement plane 38 , the respective object 13 measurably influencing these intensity distributions J1, J2 when crossing the measurement planes 37 , 38 . Furthermore, a detector device 32 is provided, which is set up to detect the influences of the first and second intensity distribution J1, J2 along a first measurement coordinate 48 and a second measurement coordinate 49 via sensors. Furthermore, an evaluation device is provided which derives comparison signals from the detected influence on the intensity distributions J1, J2, compares these with reference signals and generates at least one control signal which is dependent on the comparison.

Claims (12)

1. Device for checking and / or distinguishing falling objects ( 12 , 13 ), preferably free-falling tablets ( 13 ), with:

• - A lighting device ( 31 ) which is set up in a first measuring plane ( 37 ) to generate a first intensity distribution (J1) of light which affects the respective object ( 12 , 13 ) when crossing the first measuring plane ( 37 ) and to produce a second intensity distribution (J2) of light in a second measuring plane ( 38 ) different from the first measuring plane ( 37 ), which influences the respective object ( 12 , 13 ) when crossing the second measuring plane ( 38 ),
• - A detector device ( 32 ) which is set up to influence the first intensity distribution (J1) along a first measurement coordinate ( 48 ) and the influence of the second intensity distribution (J2) along one of the first measurement coordinate ( 48 ) in successive cuts. ver measure different second measurement coordinate ( 49 ) in transmitted or reflected light so that it detects the respective dimensions of the object ( 12 , 13 ) in the direction of the respective measurement coordinates ( 48 , 49 ), and
• - An evaluation device ( 19 ) which derives at least one control signal (S1, S2) from the recorded dimensions, which includes a qualification of the respective object ( 12 , 13 ), wherein
• - A switchable sorting station ( 21 ) forwards the objects ( 12 , 13 ) differently depending on the control signal (S1, S2).

2. Device according to claim 1, wherein the first and the second measuring coordinate ( 48 , 49 ) run approximately perpendicular to each other. 3. Device according to claim 1 or claim 2, wherein the detector device ( 32 ) comprises at least one line sensor ( 41 , 42 ; 66 ) with side by side arranged optical sensors. 4. Device according to one of claims 1 to 3, wherein the first and the second measuring plane ( 37 , 38 ) run parallel to one another or preferably lie in the same spatial plane. 5. Device according to one of claims 1 to 4, wherein the detector device ( 32 ) comprises an imaging device ( 43 , 44 ) which images the intensity distribution (J1, J2) on sensors. 6. The device according to claim 5, wherein the imaging device ( 43 , 44 ) comprises at least one imaging light guide arrangement ( 64 ). 7. The device according to claim 5 or 6, wherein the lighting device ( 31 ) has at least one infrared light source ( 33 ), and in that the imaging device comprises at least one infrared filter ( 45 ). 8. Device according to one of claims 1 to 1, wherein the lighting device ( 31 ) in the respective measuring plane ( 37 , 38 ) lying, linearly arranged light transmitter ( 34 , 36 ). 9. Device according to one of claims 1 to 8, wherein it comprises an arrangement ( 57 ) which is adapted to determine the speed with which the objects ( 12 , 13 ) move in the region of the measuring planes ( 37 , 38 ) . 10. The device according to one of claims 1 to 9, wherein it is assigned to a counting station ( 93 ) which uses the control signal (S1, S2) as a counting pulse. 11. The device according to one of claims 1 to 10, wherein the evaluation device ( 19 ) carries out at least one comparison with at least one reference signal (R) and generates the control signal (S1, S2) as a function of the comparison. 12. Device according to one of claims 1 to 11, wherein the objects ( 12 , 13 ) at least when crossing the measurement planes ( 37 , 38 ) maintain their orientation transverse to their direction of movement ( 15 ).