Electro-optical pattern recognition

(74) Representative (56) Cited publications

A / S Oslo Patent Office Dr. ing. K. 0. Berg, Oslo.

Commonly available Norwegian Application No. 2276/72 British Patent No. 1365107

BRD off. No. 2033219, 2131697

US Patent Nos. 3255357, 3837486

Teknisk Ukeblad bd 120 no. 35, 23.08.75, Ingeniørforlaget A / S, Oslo.

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The present invention relates to a method and apparatus for automatic pattern recognition of liquid containers, e.g. bottles, cans, etc. of varying size and shape, as shown in the preamble of the appended claims.

From Norwegian Patent No. 126900 there is known a device for automatically recognizing empty bottles by means of optical means by detecting the shadow images of the bottles. The known device uses a number of appropriately positioned photodetectors for detecting the characteristic data of the bottles, e.g. the bidding of the bottles. When introducing new bottle types into the market, additional photodetectors may be fitted to satisfactorily detect these bottles as well. If any bottle types disappear from the market, the machine may need to be programmed not to pledge such bottles or disassemble the photo detectors in question. When installing such a machine, it will most often be necessary to test the machine to ensure that the photodetector unit is properly aligned. In countries where there are a few collateral-worthy bottle types, this does not pose a particular problem, but in any case, the supplier's service personnel will be required to do the work, which requires a fairly comprehensive service apparatus, especially if several machines have to be adjusted in a short period of time. . Furthermore, this procedure is time-consuming and consequently costly, especially in those countries or districts where new bottle types are constantly entering or disappearing from the market, or where there are very many different bottle types. Furthermore, in the known device no means are available for returning bottles which are not mortgage-bearing.

The object of the present invention is to enable a simplified and automatic programming of the device accordingly

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the invention with respect to the liquid value of the liquid containers and characteristic data.

A further object of the invention is to enable programming and detection of the shape, color, weight and equipment of the liquid containers.

Further objects of the invention are to enable liquid containers which are not accepted by the device according to the invention to be returned to a receiving station.

These and other objects of the invention are solved as will become apparent from the following description with reference to the drawings. The features of the invention will be apparent from the following claims.

Fig. 1 shows a detector unit according to the invention.

FIG. 2 schematically illustrates the means for operating the detector unit according to FIG. 1.

FIG. 3 shows a modification of the embodiment according to FIG. 2, viewed from the side. . ''

Fig. 4 shows a further modification of the embodiment according. FIG. 2, viewed from the side.

Fig. 5 shows schematically the principle of detection according to the invention. ; ' . · J ·

Figures 6a and 6b show together in block diagram the electronics system according to the invention. ¹.

Fig. 7 illustrates the principle of detecting the special shape of a liquid container.

FIG. 8 is a further example of the detection method shown in FIG. 7.

Fig. 9 illustrates the scan angle and upper and lower limit

135639 for detecting liquid containers.

Figs. 10 and 11 illustrate detection of liquid containers with asymmetrical shape or where the liquid container is randomly given asymmetrical shape.

FIG. 12 is a block diagram of the detection system.

Figures 13 and 14 show, respectively, the scanning and recording of constrictions on a bottle and the pulse trains detected in this connection.

Fig. 15 shows means for returning non-mortgaged bottles.

Fig. 16 shows an embodiment of a front panel of the device according to the invention.

In the following, the invention is described in connection with the detection, programming and recording of bottles. However, it will be understood that the invention may also be applied to any liquid container of particular shape, color, weight and equipment, and thus is not limited to bottles.

In FIG. 1 shows a detector unit consisting of a column 1 where e.g. may be embedded 256 (256 = 2) optical fibers 2, whose ends 3 are located in a column as shown in FIG. 1. The fibers may be epoxy-embedded in the soil, and the ends 3 of the fibers will be plan-cut to achieve satisfactory light absorption.

At the other end 4 of the fibers, all the fibers are collected in a bundle and the light passing through the fibers is collected by the light focusing means 5 so that the light captured by the detector unit 1 can be detected by a photodetector 6. The only active component of the total unit as shown in FIG. 1, thus, only one photodetector 6 becomes, which also simplifies the electrical wiring and failure in connection with any defective photodetector. It will of course be possible to arrange two or more columns 1 as well as a corresponding number of photodetectors 6 if this is considered desirable for special reasons. Furthermore, it will be possible for each detector unit 1 to have e.g. two photodetectors, the fiber optics of the detector unit 1 being assembled e.g. into two bundles connected to each photodetector 6.

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Figures 2, 3 and 4 show schematically how a bottle is moved past a deflection station. The deflection station consists of a light source 18 in the form of a laser transmitter or a light bulb which, by means of lenses, produces a narrow beam of light with little divergence, e.g. about. 1 mm in diameter, a rotating mirror 8 which causes the light beam 10 to move along a substantially vertical, straight line such that the light beam hits the light sensitive points in the column 1, where the distance between the points or the fiber ends 3 is preferably equal;

For each point that the light beam strikes, a pulse is generated.

These pulse signals are converted from light pulse signals to electrical pulse signals by means of the photodetector 6, so that the output signal becomes a pulse train. In this way, a light beam sweep will produce as many pulses as the number of light deflectors in the column 1 if no bottles close the light beam.

The repetition rate of the light beam sweep together with the speed of the conveyor 7 determines the horizontal resolution in the sample recognition image (X direction).

The distance between the light sensitive points in the column 1 determines the vertical resolution (Y-direction).

In order to obtain clear resolution in the X-direction at varying transport speed, the mirror rotation must be synchronized with the band speed. This can be accomplished in various ways as indicated in FIG. 2-4. The mirror 8 is stored in bearings 9 and is connected by coupling 11 to an electric motor 14 via a shaft 12. The belt 7 (conveyor) is also driven by the motor 14 via an exchange 13. As shown in FIG. 2 and 3, the same motor can be used to operate the mirror and the tape. In order to obtain good resolution, the rotational speed of the mirror should be substantially greater than that of the belt drive shaft 7. In FIG. 3, the mirror 8 is connected to the motor 14 by a rigid shaft and couplings 11. In FIG. 4, the connection between the mirror 8 and the electric motor 14 is maintained by electrical connection, using a resolver 16, 17 or its technical equivalent. Bottles 15 are illustrated in liquid containers to be emptied.

The mirror 8 may comprise a plurality of mirror surfaces such that the unit in which these surfaces form part cross-section forms a polygon, e.g. a square. Thus, in the case of a square, the mirror 8 will generate four light sweeps per. rotation of the mirror unit

When the bottle enters the detection zone, it will prevent the beam of light from hitting all the light sensors. By detecting the various shading points as the bottle passes the detection zone, it is thus possible to easily create a clear picture of the object's contour. As schematically shown in FIG. 5, a light sweep 19 of the length of the piece h will be shadowed on the column 1 due to the bottle 20 is obtained on the scanner column 1.

In order to simplify the object's contour data, these are processed to obtain an appropriate shape.

Preferably, the calculated data for the fluid container may have the following structure: height, width, area of ​​inscribed surface, depth of constriction, characteristic angles of inclination, number of small projections and notches. All data will have to be entered with different tolerances. The machine can thus be pre-programmed with this Danish data on the various bottles. The number of data and bottles that can be programmed is essentially limited by the system's memory capacity and computational speed. An electronic microprocessor with associated electronics and memory can be used as an aid.

For each new bottle detected, the above data will be calculated. These are compared to “those from known data, and by conformity the bottle is considered to be classified and will be registered as collateral worthy.

As indicated above, the system relies on already known data. These can be programmed using finished data such as available on tape. The system also has a built-in option for self-programming (self-training). For this purpose, the microprocessor's programs may contain a separate program routine that allows this. This feature can be e.g. is activated by a key switch. The machine is programmed

13ό bU 9 now by feeding through the device according to the invention a representative selection of the bottle type to be recognized as monster-worthy.

The contour reading for the new bottle takes place as previously described, where the data is now stored in memory as new, instead of being subjected to a comparison with previously known bottles. However, it is assumed that a sufficiently large number of copies of the new bottle are recorded in order to become aware of the bottle's current tolerances.

The pledge value can be programmed using a manually operated pledge programming panel, e.g. of the type of thumbwheels, matrix panel or keyboard. The machine is then put into detection and analysis mode. The machine is now programmed to recognize the bottle it will accept and knows what the deposit value is.

When the customer is required to pledge their bottles, these are fed through the machine through the machine past the optical detecting unit, detected and sampled. The mortgage-worthy bottles are added to individual mortgage values ​​which are summed. By pressing a mortgage receipt button, a receipt will be issued stating the number of approved bottles and the sum receivable amount.

There are several problems with the registration of bottles, as both the height and the width of the bottles vary greatly. This is schematically illustrated in FIG. 9. In this embodiment, a light sweep angle of .ca is indicated. 50 °. however, the invention is not limited to such a sweep angle as it will depend on the distance from the rotating mirror to sbylenia. the minimum angle of inclination of the contour of the neck present. This can be done in the manner indicated in FIG. 7 and 8, where A represents the direction of light welding and B represents the direction of transport. The angle can e.g. be given by the difference between the first (a) and last (b) height values ​​within a certain number of sweeps, i.e. the angle indication in FIG.

has an angular value = 3 and in FIG. 8 angle value = 2. The example of FIG. 7 and 8 show the number of sweeps = 6.

135659, ..... J Furthermore, the projections and notches on the bottle, constrictions and defects will have to be taken into account. A large number of bottles are equipped with paper labels and metal caps. These may tend to detach from the bottle or may be partially torn off. If this is the case, the machine must still be able to identify the bottle, and this can be done as indicated in FIG. 10 and 11. Here, measurement is used only of the least protruding points of the bottle, so that, based on the measurements taken, an impression of the actual appearance of the bottle can be formed (Fig. 11). In other words, a symmetry calculation is made here of the assumed profile of the bottle.

To further identify the bottle one can measure its weight by means of a weight range weighing device. Furthermore, it will be possible to measure the color of the bottle, e.g. may be colorless, brown, green or other color. With regard to tolerances, however, color variations must be taken into account.

As an appropriate data structure, e.g. 16 words of 8 bits are used, where the bottle's hobby is described by 2x8 bits, the width by 2x8 bits, the area of ​​the bottle by 2x8 bits, the depth of two constrictions by 2x8 bits, where the smallest dimensions are defined by 8 bits and the respective largest dimensions are defined by 8 bits, so that the tolerance can be appropriately specified, angles are described by 6x4 bits, the smallest values ​​being indicated by 3x4 bits and the largest values ​​by 3x4 bits, the number of projections and notches by 8 bits, and the weight of the bottle with 2x4 bits with 4 bits at minimum and maximum weight respectively. In addition, various information such as color, specified by 8 bits.

As a light source can be used e.g. a halogen lamp whose advantage is i.a. is long life, easy accessibility, large color range and low power supply requirements. However, such a lamp requires expensive lens equipment in order to obtain a highly concentrated light beam. Alternatively, a continuous laser can be used whose advantage is low beam divergence, but where the service life is limited, the power supply requirement in particular, the equipment expensive and not readily available, and that only monochromatic light is emitted.

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According to the invention, it will be possible to use the lower part of the infrared spectrum from incandescent lamps, which eliminates problems associated with ordinary glass luminescence. This can be done by using visible light during all mechanical adjustments, after which filters are inserted.

The detection system will now be described in more detail with reference to FIG. 12.

Immediately before the light beam 10 hits the top fiber end 3 of the column 1, the counter 30 is reset to position 256 via the reset input 40. For each fiber point 3 hit by the light beam, a light flash is generated to the phototransistor 6, whose output signal is an electrical pulse amplified by a Schmitt trigger circuit 29. Each pulse reduces the content of counter 30 by one, i.e., a countdown is made. This continues until the light beam 10 is stopped by a bottle. The detector 31 will now detect pulses failing, generating an interrupt signal to the central control unit (CPU) 34, which reads the contents of the counter 30 immediately by the input port 32 and the data transfer path 33. The corresponding procedure will repeat for each sweep until the bottle has passed the detector. .

The memory in unit 34 will now contain a complete set of height measurements along the entire contour of the bottle. This will again be the main basis for calculating the most important characteristics of the bottle:

1. Maximum height = largest input value

2. Maximum width = number of sweeps hitting the bottle

3. The area is approximately proportional to the sum of all values ​​entered

4. Angles are measured as described with reference to FIG. 7 and 8

5. The depth of the constrictions is recorded as described below with reference to FIG. 13 and 14.

The depth of the constriction is recorded by counting the number of sweeps detected in the constriction, this being in the example shown in FIG. 13, consists of three sweeps marked with the letters b, c and d. Fig. 14 shows the measured pulse trains in connection with the sweeps a - f.

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6. Projection is recorded when a certain number of subsequent height measurements have approximately the same value, and then suddenly change.

7. Notches are recorded as specified in item 5, but where the height and depth will be below a certain value.

8. Weight is recorded as indicated earlier in the specification, using a pressure foil with e.g. digital output, which pressure foil is placed under the conveyor in a manner known per se. Weight value is input directly to the unit 34 from the weight detector 51 via the inlet 39 and the data transmission path 33, FIG. 6.

9. When recording color, a technique known per se is used in which one phototransistor 6 is supplemented with color detectors.

After determining the characteristics of the bottle, these are compared with the previously known data in the system memory.

If there is compliance, the bottle is considered classified and added value according to class. This collateral value is added to previously accumulated values.

If consistency is not found with previously known data, the bottle is by means of the thrust member 26, fig. 15, removed from the conveyor 7 and proceeded to a return path 27 and out to a receiving station 281

In FIG. 16 is an example of a front panel for the device according to the invention. The bottles are fed into an opening 25, and when all the bottles are fed, the operator pushes a receipt button 23 and then a receipt is ejected from the printing plant 21, e.g. data on the number of bottles registered and the total deposit value of the bottles. For example, if a non-recordable bottle is returned, e.g. an indicator field 24 indicates by light signal that the bottle is not accepted, and at the same time the bottle is returned to the receiving station 28. The field 22 may be useful for instruction manual or other information means.

The electronics unit according to the invention is shown in block diagram form in FIG. 6a and 6b. There are two transmission paths in the electronics unit, the data transmission path 33 and the address transmission path 91.

In the following, these two transmission paths are designated as data bus and address bus respectively.

1.0

The block 56 denotes the detector unit as shown in FIG. 1 as well as the amplifier 29. The outputs of the counter 30 are connected via the input port 32 and the data bus 33 to the central control unit (CPU) 34. The counter 30 contains an overflow indicator which, upon impact, supplies an overflow signal to the CPU. 34 via line 97 and port 41. Counter 30 is reset by means of a reset signal from port 66 via line 40. As explained in connection with FIG. 12, the residence detector 31 is in direct communication with the CPU 34. In addition to being directly connected to CPU 34 via line 93, the stay detector can also be connected via the port 41 and the data bus 33.

The data bus 33 is connected to both CPU 34 and memory 90, as shown in FIG. 6b. For entering data on new bottles, their mortgage value, etc. , data on any malfunctions, data on detected bottles and operation of various control functions in the device according to the invention, a number of inputs 35, 36, 37, 38, 39, 32 and 41 have been used, which can be selectively activated by activation signal. on respective address lines 96 A, 96 B, 96 C, 96 D, 96E, 96 F and 96 G, and which inputs are all connected to the data bus 33.

Next to the port 35, a detector 42 may be connected for detecting a bottle in the receiving or returning station 28, a pushbutton 43 for the Print Last Pants function, and a pushbutton 44 for initiating a test operation.

The inputs 36, 37 and 38 in the example shown are respectively connected to the outputs of the thumbwheel turns 45 and 46, 47 and 48, 49 and 50. The turns 45-50 are used in programming the deposit value for the individual bottle types. However, it will be possible to use another mortgage programming panel, as suggested earlier in the description.

In the example shown, the inlet 39 is connected to the output of a weight detector 51, which detector is preferably of the step type with digital output. Furthermore, the inlet 39 is connected to the outputs of a pushbutton 52 for tripping the function New bottle type, a pushbutton 53 for restarting the device if

135639.

..... which for some reason does not work, a push button 54 for acknowledgment from the printing plant 69. The push button 54 and the printing plant 69 correspond respectively to the push button 23 and the printing plant 21 in fig. 16. Furthermore, a mortgage value priority switch 55 is connected to the inlet 39.

The functions associated with the port 32 are described above.

In the example shown, the inlet 41 is connected to a bottom detector 57 for the light sweep 10, respectively, a cheat detector 58 for detecting e.g. malfunction of the detector unit, the printing plant, etc., a light source error detector 59, a paper end detector 60 for detecting missing paper in the printing plant 69, a motor stop / overload detector 61, a mains voltage weight detector 62, and a detector 63 for detecting mains connection . The detector 62 is preferably in direct communication with the CPU 34 via the interrupt signal line 93, and the detector 63 is in direct communication with the CPU via the zero set line 94.

For controlling various output functions, indicators etc., a number of outputs 64, 65, 66 and 67 are selectively provided to the data bus 33 which are selectively activatable with activation signals respectively on the address lines 96 H, 96 I, 96 J and 96 K.

The ports 64 and 65 are connected to the printing plant 69, where data on numerical value are fed over the lines 70, data on the digit number are fed over the lines 71, the signal for paper feeding is fed over the line 72 and the signal for activating the paper scissors in the printing plant 69 is fed over the line 73.

The output 66 feeds reset signal to the counter 30 via line 40. The stay detector 68 connected to one of the outputs of the output 66 causes the Program OK lamp 74 to illuminate under normal operating condition. The output 66 will also control the pledge register 75 which is a counter indicating total registered pledge value, the bottle register 76 which is a counter indicating the total number of registered bottles, an alarm clock 77 activated by malfunctions, a bottle return mechanism 78 as described in connection with FIG. 15, a conveyor motor 79 (corresponding to the motor 14 in FIGS. 2-4), and the light source 80 for sweeping the light beam toward the detector unit (the light source 80 corresponds to the light source 18 in FIG. 2).

The outputs of port 67 are fast respectively to a red lamp 81 and a green lamp 82 for light in the acknowledgment button 54, the green lamp will light as bottles are fed into the device, and the red lamp will replace the green lamp if the acknowledgment button is pressed. for printing the desired data on the recorded bottles, to a lamp 83 for indicating that the detector column 1 must be cleaned or dust-dried, since dust on one of the fiber ends 3 may cause malfunctioning; to a lamp 84 for indicating that the conveyor 7 needs to be washed, as the sun from fed bottles will eventually cause the tape to become sticky, to lamps 85, 86 and 87 respectively for overload, paper finish in the printing plant and lamp failure, and to a lamp 88 for indicating an unapproved bottle, which lamp 88 may communicate with the indicator 24 in FIG. 16.

The inputs 35, 36, 37, 38, 39, 32 and 41 and the outputs 64, 65, 66 and 67 are selectively activatable via the address lines 96 AK, where the activation signals are applied via the address bus 91 to the input / output decoder 89, which decoder with respect to input / output is controlled from CPU 34 via in-line 95 and out-line 98. Request for data memory access to be enabled via line 92 to CPU 34.

It will be apparent to those skilled in the art that the embodiment of FIG. 6a and 6b, embodiments of the electronics unit according to the invention serve only to illustrate the idea and embodiment of the invention, but that alternative embodiments may be possible within the scope of the invention. Thus, the number of inputs and outputs could be increased or decreased, functions other than those associated with the inputs and outputs could be linked to the electronics unit and the circuitry could be adapted to the current needs and standard equipment, e.g. with regard to micro-processor, whichever is selected and the software preferred.