DE8702811U1 - Test device - Google Patents

Description

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Test device

The invention relates generally to a testing device for objects and is particularly directed to such testing devices for objects that work with a recording device such as a video camera for examining the objects.

Nowadays, instead of the older hand-held inspection and visual inspection, an automatic object inspection device is used, in which a photoelectric transducer sensor is used to pick up the object and its output signal is processed electronically. In such cases, many devices use a video camera in the form of a pickup element such as a CCD or the like to pick up an object to be inspected illuminated by a light source by receiving the reflected light emitted by the object. Then, a corresponding video signal is generated by an electronic-only circuit to perform the inspection of the object.

The requirements that a device for checking the appearance of an object, which is intended to replace human inspection, must meet include requirements as diverse as the shape of the object, its dimensions, irregularities in its appearance, adherent foreign particles or inclusions, etc.

In addition, there is a variety of objects to be examined, from flat board-like objects to cubic objects with large irregularities, whereby normally the examination does not have to cover the entire object, but the requirements are to carry out a limited examination of a part of the object.

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If, for example, a crack in the body of a transparent glass bottle, in which foreign bodies are enclosed, is to be examined (see Fig. 3), examination areas or zones 2 and 3 - which are shown in dashed lines in Fig. 3 - are determined, whereby only these zones need to be examined, and the image signals of these zones are electronically analyzed, whereby defects or the like in these zones are determined.

The designation of such special inspection zones 2 and 3 is referred to as arranging windows or performing masking <Q. Fig. 4 shows such an example, where 4 denotes a recording screen of a video camera or the screen of a video monitor (not shown) connected to the video camera. In the screen 4, the aforementioned inspection zones or windows 2 and 3 are provided as shown in Fig. 4 and only the areas within the windows 2 and 3 are the actual inspection zones when inspecting the bottle. After the windows 2 and 3 have been defined, the

The bottle 1 to be examined is conveyed to the position indicated by dashed lines in Fig. 4 and then recorded by the video camera, whereby the necessary areas of the bottle 1 or, in other words, only the windows 2 and 3 are examined.

OEthere are different possibilities such windows 2 and 3 2B

to be provided, e.g. an opaque plate with through-openings corresponding to the windows 2 and 3 is arranged between the video camera and the bottle 1 to be examined, whereby physical windows 2 and 3 are provided, or means are provided to transmit the image signal of the

Video camera electronically by entering horizontal and vertical coordinates corresponding to windows 2 and 3, or electronically entering such windows 2 and 3 through computer software. In such cases, if the windows are provided as described above and only the areas within the windows are to be examined,

It is important that the object to be examined is recorded in exactly a predetermined position.

For this purpose, according to the state of the art, if the object to be examined is to be transported on a conveyor of a production line and examined through windows using such a method, a special device must be provided for determining the position of the object in order to determine whether the object to be examined has reached the correct position or not. In a practical example, an arrangement was formed of a light projector and a light-receiving sensor in order to determine the position at which the object passes the light beam. This arrangement is therefore complicated and its application is limited.

The invention is therefore based on the object of creating a testing device of the type mentioned, which is simple in construction, wherein the examination zones or windows should be automatically adjustable.

This task is solved by arranging a light source in such a way that it illuminates one of the objects to be examined,

that a photoelectric recording device is arranged so that it records the light reflected or transmitted by the illuminated object and, depending thereon, generates an image signal of this object including a synchronizing signal, and

that an inspection device receives the image signal for checking whether the object being examined has a defect or is free of defects, the inspection device comprising: A) a reference position determination circuit arrangement,

which generates a reference position signal/ which is based on a partial image signal in the first partial image of the image signal and the

Synchronous signal,

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B) an examination zone position setting circuit that stores an examination zone having a predetermined shape and generates a control signal based on the reference position signal and the synchronous signal;

C) an examination zone control circuit which receives the image signal from the recording device and the control signal and outputs a partial image signal in a second field of the image signal from the recording device within an examination zone determined by the control signal; and

D) an evaluation circuit/ which evaluates the image signal from the

r , inspection zone control circuit receives and judges whether the object under inspection has a defect or is free from defects.

Important details, features and advantages will become apparent from the following description of the invention with reference to the accompanying drawings. In all figures, identical objects are provided with identical reference numerals. They show:

Fig. 1 and 2 are schematic diagrams for explaining the operation of the invention;

Fig. 3 is a schematic diagram showing an investigation zone

of an object to be examined;

Fig. 4 is a front view showing the screen of a Monitor-3Q television receiver;

Fig. 5 is a block diagram of an electric circuit of a main part of an embodiment of the invention;

Fig. 6 and 7 are schematic diagrams of parts of another embodiment of the invention.

An embodiment will be explained in detail below with reference to Fig. 5 which shows a block diagram of the embodiment. A video camera 5 is used as a recording device and consists of, for example, a CCD (charge coupled device) as a photosensitive element which records an object to be inspected, and a synchronizing signal separator 6 which separates a vertical synchronizing signal V and a horizontal synchronizing signal H from the composite video signal supplied from the video camera 5. A reference position detecting section 7 which determines a reference position based on the signal in the first field of the image signal of the object to be inspected from the video camera 5 detects the part of the image signal in the first field which is predetermined.

and generates a reference position signal for a window or an examination zone. This reference position detection section 7 is connected to the outputs of the video camera 5 and the synchronous signal separator 6. An examination zone position setting section 8 receives the output signals from

the synchronous signal separator 6 and the reference position detecting section 7 to determine a relative position between the previously set inspection zone pattern of the object and its image based on the reference position signal 25, and an inspection or examination section 9 processes the image signal of the second partial image within the inspection zone pattern set by the inspection zone position setting section 8 to detect defects or abnormalities within the inspection zone of the object under inspection and outputs the resulting judgment signal to the outside. For this purpose, the inspection section 9 receives the output signal from the video camera 5 and the output signal from the inspection zone position setting section 8. In such a case, the separator 6, the detecting section 7, the position setting section 8 and the examination section 9 form the inspection or examination device 14.

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The operation of the above-mentioned object inspection apparatus 14 according to the invention will be described below with reference to Figs. 1 and 2. The object 1 to be inspected, such as a glass bottle or the like, is transported by a belt conveyor 11 in the direction indicated by arrow A. A light source 12 irradiates light onto the object 1 to be inspected on the belt conveyor 11 and is arranged opposite the video camera ⁵ 10 with respect to the belt conveyor 11. In this case, the video camera 5 is photosensitive to the light passing through the bottle. A monitor television receiver 13 displays an image of the glass bottle 1 as picked up by the video camera 5, the inspection apparatus 14 having the detection section 7 and so on as shown in Fig. ⁵ , which are formed by an electronic circuit.

I Fig. 2 shows a monitor screen 13A of the monitor television receiver 13 of Fig. 4. The images IA and IA ¹ in Fig. 2 I 20 show the same bottle 1 as the object to be examined, and 2,2* and 3,3* are windows or examination zones in the images IA and IA ¹ of the bottle 1, respectively. 15 is the position detection zone for the glass bottle 1 and 16,16' are the reference detection positions of the images IA and IA'. IO 26

\ The device will now be explained with reference to Fig. 5. The image signal of the examined object or the glass bottle 1, as recorded by the video camera 5, is fed to the separator 6,

the detection section 7 or the examination section \9 30. The synchronous signal separator 6 separates both the vertical synchronous signal V and the horizontal synchronous signal H from the video signal mixture of the video camera 5 and passes these signals to the detection section 7 and the setting section 8. It goes without saying that the separator 6 can be omitted if the video camera 5 itself has the feature of separating the synchronous signals and the synchronous signals are emitted separately from the image signal.

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The respective synchronizing signals V and M are used to determine the coordinates of the positions on the screen in the electronic circuit 14 by which the examination device according to the invention is formed.

The synchronous signals H and V are both supplied to a position detection zone setting circuit 7A of the reference position detection section 7, which then sets its zone determines or specifies, e.g. the position detection zone 15

(Fig. 5). This zone 15 is previously determined in accordance with the _type of application of the device, so that the setting circuit 7A consists of, for example, a counter, an IC memory or the like to store the predetermined zone 15. At the same time, the image signal from the video camera is fed to a position detection circuit 7B of the reference position detection section 7, which then generates a detection signal that corresponds to a partial image signal in the first partial image of the image signal and to a part of the object being examined. 1 of the glass bottle 1 within the position detection zone 15 |

This detection signal is then fed to the input I

Control circuit 7A. In the example according to \ Fig. 2, for example, shows the outer surfaces of the left side walls of the; Images IA and IA ¹ of the glass bottle 1 set as the reference j

&ngr;- 25 difference detection positions 16 and 16', so that the type of position j

tion detection of the position detection circuit 7B is such that \

that the difference between the lightness and the darkness |

unit of the bottle 1 on the outer surface of the left side wall i

section is detected by a comparator and the side edge of the object or the like is detected.

When the outer surface of the left side wall of the object 1 under investigation, as it is conveyed on the conveyor belt 11 in Fig.l in direction A, is within the position detection zone 15, a reference signal generator circuit 7C receives the output signal from the detection circuit 7A and generates a signal η which corresponds to the reference signal, namely a po-

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position reference signal used to determine the position of the windows or the examination zones 2 and 3. This position reference signal m is supplied to the examination zone position setting section 8. In this case, the setting section 8 is provided with an examination zone pattern circuit 8A in which a given examination zone pattern is previously set and stored. The signal of the circuit 8A corresponding to this given examination zone pattern is supplied to a pattern position setting circuit 8B of the setting section 8. In addition, the position reference signal m from the reference signal generator circuit 7C of the reference position detecting section 7 is supplied to the pattern position setting circuit 8B of the setting section 8, and the examination zone pattern of the examination zone pattern circuit 8A is controlled by the signal m so that it is positioned at a predetermined position relative to the image IA.

For example, in Fig. 2i, 16 denotes a time at which the reference detection position was detected. If this time is assumed to be ti, a time t2 which differs from the time ti by χ (time delay) is set to correspond to the left side edge of the inspection zone or window 3, and a time t3 which differs from the time t2 by x ¹ is set to correspond to the left side edge of the inspection zone or window 2. Even if a reference detection position 16' of the image IA ¹ is detected at the left side of the screen 13A, if the values χ and x ¹ are kept constant, the relative positional relationships of the inspection zones 2' and 3" of the image IA' of the bottle 1 always remain constant.

In addition, in the above explanation, the surface of the left side of the image of bottle 1 was used as the reference position

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A method can also be considered whereby the surfaces of the left and right sides of the image of the bottle 1 are determined as reference positions and the examination zones or windows 2 and 3 are arranged between them. However, it is also free to select one or more detection points as reference positions depending on the shape of the object to be examined.

Then, when the positioning of the examination zone pattern is determined, one of a control signal generator circuit 8C of the setting section 8 receives the output signal of the setting circuit SB, generates and supplies a control signal η. to the examination section 9. In order for the examination zone pattern circuit 8A to store this pattern, it is formed, for example, by an IC-ROM (integrated read-only memory) or the like.

In addition, the pattern circuit 8A receives an address signal to set the position of the pattern from the pattern position setting circuit 8B, which is formed of, for example, a counter/pulse generator or the like, to divide and limit the horizontal position of the pattern. It goes without saying that this pattern position setting circuit 8B is controlled by the respective synchronous signals H and V from the synchronous signal separator 6 to set the windows or the examination zones 2 and 3 within the screen to the precisely correct positions.

The control signal η from the control signal generator circuit 8C is supplied to an examination zone control circuit 9A of the examination section 9 to designate the examination zones or windows 2 and 3. The examination zones Control circuit 9A, to which the image signal from the video camera is fed, can be, for example, a circuit which only operates when an image signal is present in the examination zone _.

which are determined by the control signal &eegr;, supplies the image signal in the second sub-image to an evaluation circuit 9B, or to a circuit which directly controls the operation of the evaluation circuit 9B , such as a computer or

The judging circuit 9B carries out the examination and the judgment of only the image signal in the second field within the inspection zones 2 and 3, and outputs the judgment result, namely, a signal representing the presence or absence of a defect or abnormality in the object 1 , to the outside via an output terminal 10.

Then another application example of the present

The invention is explained with reference to Figs. 6 and 7. If, for example, an object to be examined, such as a glass bottle 1, is to be examined at different angles , it is sufficient to rotate the glass bottle 1 during transport on the conveyor belt 11. If, for example, the glass bottle 1 in Fig.

6 is passed by a fixed camera (not shown in Fig. 6) and rotated, moving its image from the right to the left end of the monitor screen 13A and the examination is carried out in three positions, i.e. in the central position, in the right end position and in *O' 25 the left end position on the monitor screen 13A, then the same bottle 1 is examined at three different angles. In this case too, the respective examination zones can be correctly set by setting the reference detection position on the outer surface of the left side wall of the bottle 1 is determined, eg, the times P ₉ O and Q, so that the special inspection purposes can be fulfilled. At this time, for example, although the operation of the judging circuit 9B is normally turned off, a control signal for starting the operation is output via a terminal 9C (Fig.

5) is fed to the evaluation circuit 9B, so that this synchronous with the conveyor speed of the belt conveyor 11

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works so that the judging circuit 9B performs its judging |

result at three points in time at the appropriate positions

tions of the bottle 1 on the monitor screen 13A. 1

Since the precise setting of the examination zones can be carried out automatically, ■ as explained above,

the timing of the control signal is not of the highest precision- \

This control signal can be, for example, from a |

rotating encoder 9D (Fig. 5 ) which is used for |

Conveyor speed is synchronized. I

It is also possible to place the bottle 1 on the straight <

to convey the bottle 1 along the belt conveyor and thereby rotate it (Fig. 7), \ to divide the belt conveyor 11 into four partial belts HA, HB, HC, i and HD, whereby the conveying speeds of the individual partial belts following sequentially differ slightly, in order to convey the bottle 1 during its rotation. Since
Methods for rotating a bottle during its conveyance are known in various ways, a desired method can be freely

to get voted.

The above explanations concern the case where the
Light passing through the transparent glass bottle to be examined from the video camera is photoelectric or

trically recorded and the image signal processed.
When the present invention is used to
opaque object, such as a cylindrical metal can,
check, the light from the light source is reflected by the opaque object
reflected and this reflected light is absorbed by the

Video camera light or photoelectrically recorded and the
The resulting image signal is processed in a similar manner as above
The opaque or non-transparent object can
then be examined.

Furthermore, the explanation of the operation of the examination or testing device according to the invention was given under the assumption

supposition that the bottle 1 is moved in the horizontal direction, while the vertical direction remains unchanged, and the coughing of the examination zone is only the horizontal control is intended. However, if the Bottle 1 is moved in the vertical direction, the pattern of the examination zone is similarly controlled in the vertical direction.

If after the invention the investigation and assessment

only for desired parts of the object under investigation with a simple circuit design, The examination zone can be automatically adjusted according to the desired part of the object to be examined if the object is within the field of view or recording of the video camera. According to the state of the art, the object being examined had to be placed in a precise, predetermined position during the examination, because the examination zones were in predetermined positions within the field of view of the video camera

In other prior art methods where the examination zones were determined automatically, the entire image of the object had to be recorded and analyzed, after which the procedure for setting an examination zone was carried out by computer software, which required a considerable amount of processing time.

According to the present invention, a specific position of the object is determined, this specific position tion is captured by the image signal in the first partial image from the video camera and the examination zone is set by determining this position as a reference and only this set examination zone is examined by the image signal in the second partial image. The assessment can therefore be very can be carried out quickly. In addition, the invention allows multiple examinations to be carried out within one screen.

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Claims (1)

1. Claim Testing device for objects, characterized by that a light source (12) is arranged so that it illuminates one of the objects (1) to be examined, that a photoelectric recording device (5) is arranged so that it records the light reflected or transmitted by the illuminated object (1) and, depending thereon, generates an image signal of this object (1) including a synchronous signal, and that an examination arrangement (14) receives the image signal for checking whether the examined object (1) has a defect or is free of defects, the examination arrangement (14) comprising: A) a reference position detection circuit arrangement (7) which generates a reference position signal based on a partial image signal in the first partial image of the image signal and the synchronizing signal; B) an examination zone position setting circuit (8) which stores an examination zone having a predetermined shape and generates a control signal based on the reference position signal and the synchronous signal; Postal address: PO Box 260132 D-8000 Munich 26 Office address: * 6jeinS<jo/fitr äßftO, OMh^ Accounts for official fees: Postgiro Munich, account 195 75*803 (bank code 700100 80) EPA'Kto.28000206 &igr; C) an examination zone control circuit (9A) which receives the image signal from the recording device (5) and the control ( signal receives and a partial image signal in a two- th partial image of the image signal from the recording device (5) f ₅ within an examination zone which is determined by the ;' control signal; and D) a judging circuit (9B) which receives the image signal from the inspection zone control circuit (9A) and judges whether the inspected object (1) has a defect or is free from defects. 2. Device according to claim 1, ! vy characterized by that the reference position detection circuit arrangement (7) a position detection circuit (7B) which receives the image signal ' from the recording device (5), a position detection j< sungszone adjustment circuit (7A) which provides an output signal L from the position detection circuit (7B), and a reference signal generating circuit (7C) _which receives an output signal from the position detection zone setting circuit (7A) and generates the reference position signal (m). 3. Device according to claim 2,
"") ₂₅ characterized by that the examination zone position setting circuit arrangement (8) comprises an examination zone pattern circuit (8A) which stores the examination zone in a predetermined form, a pattern position setting circuit (8B) which supplies a signal which is assigned to the examination zone from the examination zone pattern circuit (8A), receives the synchronous signal and the reference position signal (in) before the reference signal generating circuit (7), and has a control signal generating circuit (8C) which receives an output signal from the mu- 3g sterposition setting circuit (8B) receives and generates the control signal (n)« &diams; 4.4 «ti «« · &bull; . · · »II, lit 4* Device according to one of claims 1 to 3, characterized by a synchronous signal separator (6) which separates the synchronous signal from the image signal from the recording device (5), 5. Device according to one of claims 1 to 4, characterized in that the sync signal includes horizontal and vertical sync signals. 6. Device according to one of claims 1 to 5, characterized by a conveyor (11) for conveying several objects (1) into the receiving device (5) !5 over. 7. Device according to claim 6, characterized in that the conveyor is a belt conveyor (11). 8. Device according to claim 7, characterized in that the belt conveyor consists of several parallel partial belts (HA, HB...) which can be moved at sequentially different speeds, whereby the object (1) can be rotated in the field of view of the recording device (5) during transport. 9. Device according to one of claims 1 to 8, characterized in that that a circuit (9D) supplies an operating control signal to the assessment arrangement (14), whereupon the latter determines at several positions whether the object (1) is faulty or fault-free. 10» Device according to claim 9, characterized in that the operating control signal is generated synchronously with the conveying speed of the belt conveyor (Ü)* Hi Device according to one of claims 3 to 10» characterized in that the pattern position setting circuit (8B) determines a relative position between the examination zone and a reference point of the image on the basis of the reference position signal.