DE102006015963A1 - Method for optically checking test objects with variable parameterization and device therefor - Google Patents

Abstract

A method and a device for optically checking test objects are described. At least one image of the test object is recorded by at least one camera and the camera images are automatically evaluated by means of an image evaluation unit connected to the camera with the aid of calculation methods, the images transmitted by the camera being carried out by the image evaluation unit by means of a first active parameterization which is used for assessing the test object, are checked and the test results, based on the first parameterization, are output by a result output device and a second parameterization is carried out in parallel to the image evaluation with the first active parameterization by a user and the camera images through the Image evaluation unit can be checked by means of the second parameterization and the test results, based on the second parameterization, are displayed by the result output device and with no interruption of the test Fung, the image evaluation unit can be operated in such a way that the second parameterization is used as active parameterization for assessing the test objects during the test run and the first parameterization becomes inactive.

Description

The The present invention relates to a method for optically examining test objects, which in particular by a transport device a relative speed have, with a changeable Parameterization and a corresponding device for this.

at the optical inspection of test objects is the parameterization or setting with regard to the test results very important. For this parameterization or setting count, for example the position and shape of the test area, the maximum allowable Size of defects that shaping or visibility of the error. These criteria serve as a basis for the Assessment of whether the test object is flawless or not, or whether it is a committee or the test object can be classified as acceptable. If the parameterization or these criteria for the image evaluation are optimized, so does the actual Committee of the test objects also found in the review Committee. However, the parameterization is actually present Circumstances are often not optimally adapted, i.e., that a pseudo error rate is present and the parameterization must be re-made. This As a result, the test procedure is not effective and reprogrammed the parameterization for the image evaluation unit or re-entered.

Therefore It is an object of the present invention, a method or a Device for optically checking test objects with the pseudo error rate being as low as possible, that is the actual Committee identified in the review Committee if possible corresponds or that this difference is as small as possible.

These Task is procedurally according to the features of claim 1 and device technology according to the features from claim 5 solved.

Of the The invention is based on the idea that during the automated verification of the test objects in parallel with a review changeable Parameters, i. made with a second parameterization is, depending on the determined reject rate of the first and second parameterization while of the test run the variable second parameterization as active parameterization can be used. This makes it possible for a user, without Interruption of the automated test to change the parameters so that the committee determined corresponds to the actual committee or that the optical monitoring the actual Conditions can be optimally adapted without the test procedure interrupt.

According to the invention discloses a method for optical inspection of test objects, which in particular by a transport device a relative speed comprising taking at least one image of the test object of at least one camera and an automated evaluation of the Camera images by means of an image evaluation unit connected to the camera is made by means of calculation methods. It will be the transmitted from the camera Images through the image evaluation unit by means of a first active Parameterization checks which for the Assessment of the test object is used, and where the test results based on the first parameterization of a result output device be issued. Furthermore, it is parallel to the image analysis with the first active parameterization of a user one second parameterization made, the camera images through the image evaluation unit can also be checked by means of the second parameterization, and where the test results based on the second parameterization of the result output device being represented. Then it can without interruption of exam the image evaluation unit are operated such that the second Parameterization for the assessment of the test objects during the test run is used as active parameterization and the first parameterization becomes inactive. As a result, in such an optical inspection, the Parameterization without interruption of the test run can be changed or switched, so the pseudo error rate as possible low, that is, the actual scrap is the one determined during the review Committee if possible corresponds, respectively, that the difference between the actual Scrap rate and the identified reject rate as far as possible is low.

Further advantageous embodiments will become apparent from the dependent claims. So become the test objects according to the assessment the active parameterization as a committee or non-committee. This applies to both the first specified parameterization, which is active at the beginning of the test run is as well as for the second parameterization, which varies by a user and, if necessary, as an active parameterization by the user is used.

According to one preferred embodiment of Invention will change the second parameterization via a data connection, in particular a network connection or an Internet connection, fed into the image evaluation unit.

Further it is beneficial if the test objects based on the assessment of the test results the image evaluation unit are discarded. This can be special by an ejection device or a blowing out of the test objects which classifies as scrap by the image evaluation unit have been.

According to one Another aspect of the present invention is a device for optical checking of test objects provided, which in particular by a transport device have a relative speed. The device according to the invention in particular by the features of the method according to the invention operated. The device according to the invention has this at least a camera for taking at least one picture of the test object, a lighting device for illuminating the surveillance area the camera and an image evaluation unit for automatic evaluation the camera images using calculation methods on which connected to the camera. In the automated test procedure For this purpose, the steps according to the inventive method used.

One Another advantage of the invention is that a network camera is provided, which is connected to a computer, which in particular several CPU cores or virtually replicating multiple CPU cores. As the individual program parts or tasks (or tasks) are performed at the same time, is one such multitasking Device particularly advantageous, since with such an architecture the software (multithreading) can simplify the execution because more important tasks or tasks are executed first. Furthermore, it is a Advantage that when using a network camera no separate Picture grabber card (frame grabber) must be used. Thereby are the costs for the device low and further one can on a standardized Picture Transfer Protocol To fall back on.

According to one preferred embodiment a high-speed camera is provided, preferably a camera with Gigabit Ethernet technology, which provides an image capture rate from 50 to 300 Hz, in particular substantially 100 to 200 Hz.

Of Furthermore, it is advantageous if the lighting device pulsed Diodes, in particular a bright field and dark field illumination produce. It can the bright field and dark field illumination separated from each other in the intensity to be controlled. As a result, small changes can occur of the test object, For example, a small dent in a lid made well visible become.

According to one preferred embodiment of Invention, a light barrier is provided to the flashing of the LED lighting and image capture trigger.

If an ejection device is provided, which those test objects which of the image evaluation unit classifies as scrap can be used by the image evaluation unit be separated from this immediately.

The The following drawings show prints during the inspection according to the invention.

1 shows a screen shot during the optical inspection of a can part,

2 shows another expression in the optical monitoring of 1 .

3 shows a further expression of the optical monitoring according to the invention,

4 shows another screen shot with respect to the optical monitoring, and

5 also shows a screen shot of the optical monitoring according to the invention.

The in the 1 to 5 shown embodiment of the invention relates to the optical monitoring of a lid or a bottom of a can, which is to be checked in mass production at high speed.

To the manufacturing process of the test objects These are at high speed of the test device according to the invention fed. It can up to 3000 test objects per minute at high speed of the device according to the invention be checked with the method according to the invention, each one a single test object it is judged whether the test object is to be singled out as a committee.

For this purpose, in particular a Gigabit Ethernet camera is used, which receives a recording of the test object or the can lid or bottom of the can at a predetermined position, in particular a laser light barrier activates the camera and also the lighting device. Then, a digital image is sent directly from the camera to the image evaluation unit, where the digitized image is evaluated in real time. If a test object is classified as scrap by the image evaluation unit, then this test object can be rejected by a subsequent ejector be or blown out. In this case, the test objects located on a conveyor belt can be tracked by means of a rotary encoder, which is coupled via the drive shaft of the conveyor belt. For this purpose, the rotary encoder of the image evaluation unit communicates the angular momentum, whereby the distance traveled by the conveyor belt can be calculated from the frequency of the pulses. In the event of a faulty test object or a defective cover, the ejection device then shoots this cover from the conveyor belt with a compressed-air pulse.

at this non-contact Inspection can be a high measurement accuracy and high inspection speed the individual test objects be achieved in mass production, in particular test objects Shells lined and unlined (unlined). In this optical review can both the presence of an object, an object count or Station identification (tool identifier) and the geometry of the test object to be checked. In the geometric review is it is for example a surface test, deviations in form (dents), surface defects (Scratches, cracks), roughness (microstructure), waviness (microstructure), surface texture (Marbling), surface properties (gloss) as well as a quantification of the errors, effect of the errors and additional. In the case of liner machines, it is possible to apply the sealant For example, be checked.

The UUT is a molded shell after the application of the sealant (Compound) in the liner stations. To identify a particular Liner station is the corresponding shell provided with a mark. It can the object surface and variants of the test objects detected and monitored be, in particular in the location of the test areas an outer curl and an inner curl is provided or checked. In such a optical review can up be checked at 50 parts per second where as the test time per test object a maximum of 20 milliseconds, including image acquisition are. At variable distances between the lids must be dependent on the web speed can be checked in exceptional cases with shorter cycle times, with a minimum test time results when the lids abut each other and from it a Clock rate of about 100 Hz at web speeds of 300 m per minute and a lid diameter of about 60 mm results.

to Evaluation of the images in high speed and for control the inspection process including the tracking of individual Cover on the conveyor belt until the ejection device, a computer or computer is used. Advantageous are multithreadingfähige Systems giving the opportunity have multiple programs or tasks or tasks at the same time Time to be executed. If too many program parts or tasks (tasks) are executed at the same time and therefore an overload threaten, such systems have the property, always the most important Tasks first and to rank the tasks still to be done according to importance. Naturally the application software must support these functionalities and according to specific guidelines be programmed. Particularly suitable are computers or computers, which have multiple CPU cores (multiprocessor systems) or can virtually replicate multiple CPU cores. You can do this for this Software architecture (multithreading) perform very well.

At the computer or computer and thus also to the image evaluation unit the camera is connected. These are in particular to a network camera, which is not a separate image capture card (frame grabber) must use. Thus, the costs are low and one can resort to a standardized image transmission protocol, without a special solution is required. Another advantage is that, in principle, if it allows the computing power, can operate multiple cameras on a single computer. An elaborate Multichannel imaging rate is in such use of these Technology (network camera) not required.

Furthermore is the computer with an input / output card (digital input and output) outputs in 24 V) to detect the encoder status for the cover tracking on the conveyor belt and the state of the photocells equipped, which is the image acquisition trigger, as soon as a lid is in the shooting position under the camera.

The optical monitoring can also with a PLC control or plant controls in the Production communicate, the ejector directly from the image evaluation device is activated.

As already mentioned, is the software of the computer of the image evaluation unit multitasking and multithreaded. The tasks or tasks described below can be independent of each other to run on the computer. The tasks or tasks are again in independent subtasks or subtasks.

The automatic or automatic task has the highest priority for the test run. The automatic task carries out control functions, such as the tracking and management of the lids on the conveyor belt, as well as the control of the ejection the input / output card, the evaluation of the pictures and the feeding of data into the tasks statistics and parameterization.

The Statistics is the second highest priority task. The statistics or the statistics task collects data that is transferred from the automatic task to the disposal be put. In the event of high data volumes, the data is queued and processed as soon as a corresponding capacity is available. In the statistics, the frequency certain cover defects (scratches, dents, dirt, deformations) dependent on from the time or the period, the production rate, the position on the lid and on a specific production machine (liner station) to be viewed as. From this, conclusions can be drawn on the quality level of production and also on the machine condition.

The Parameterization or adjustment of the inspections has only for the time being a low priority. The Parameterizing or setting the inspections is used to individual testing areas represent (graphically and in numbers) and adjust, further a selection of the image source is made. This can happen the last picture taken of the production, optionally also Images of defective, correct or accidental lids act, where The image source can also be on the hard disk of the computer. Setting criteria this includes the position and shape of the test area, the maximum permissible size of defects, the expression or visibility of the error. These criteria serve to distinguish lids classified as scrap or not as scrap become. Minor errors in the setting of these criteria lead to an inappropriate adaptation to a high pseudo error rate of Lid production, i.e. image monitoring has a higher error rate captured as actual is present.

Of the Task of the parameterization provides that independently of the automatic task another evaluation task can be started and operated. This evaluates according to identical Auswertprinzipien an image, where but a lower priority than the automatic task is present. This second evaluation task resides as a copy in the main memory of the Calculator and can be started at any time from the parameterization task so that this second parameterization for the assessment of the test objects while of the test run as active parameterization for the automatic task is used. This is the first parameterization of the automatic task, that is, the first parameterization is no longer used in the automatic task.

The inventive method is due to this process optimization in real time (Hot Edition) especially beneficial because of the actual production and monitoring simultaneously and automatically before loading changed parameters in the monitoring process can be made and followed up with new parameterization can. It can the new product parameters or test parameters with a mouse click be accepted in real time and used without the production changed or must be stopped when the parameters or the parameterization changes.

As well The current criteria in the parameterization task are as follows one independent of the automatic task Copy in memory, regardless of the currently current Inspection criteria checked or changed to become, since these for the ongoing production needed become. Thus, the production and especially the Does not affect the reject rate, because the user can do the second parameterization as a virtual check next to the evaluation with the first parameterization to a result output device or on a computer screen and if the second parameterization due to the parallel evaluation, a better reject rate, i. lower Displays the reject rate, so the user without interruption exam the image evaluation unit the second parameterization as active parameterization assign, so that the test objects or can lid according to the check with the second parameterization of the ejector singled out be when the test object has been classified by the image evaluation unit as a reject.

• – Das System kann mit bereits geprüften bzw. bewährten Inspektionsparametersätzen arbeiten, während ein Benutzer parallel während der Produktion weitere Inspektionsparametersätze erstellt bzw. verändert. Um die Praxistauglichkeit der Einstellung zu testen, werden hierzu Kopien der Kamerabilder verwendet, welche der Automatiktask dem Parametrisierungstask zur Verfügung stellt. Andererseits kann man ein Bild oder eine Vielzahl von Bildern laden, welche das System in der Vergangenheit auf der Festplatte gespeichert hat und testet daraufhin die veränderten/bestehenden Parametersätze. Die Produktion ist hierbei nicht gefährdet, da alle Subtasks des Automatiktask stets höchste Priorität haben und da erst dann andere Tasks bzw. Aufgaben mit niedrigerer Priorität ausgeführt werden. Ferner ist die Integrität der wichtigen Daten garantiert, da lediglich auf die Kopien von Datensätzen zurückgegriffen wird.
• – Darüber hinaus kann man ohne bedeutenden Zeitverlust (einige Millisekunden) die Kopien von Datensätzen (Inspektionsparameter, Inspektionsbereiche) austauschen. Dies bietet die Möglichkeit, dass (ohne Stop der Produktion) Parameter verändert werden. Somit ist das System echtzeitfähig.
• – Sofern die Kopien der Kamerabilder in den Parametrisierungstask eingespeist werden, können parallel die Auswirkungen von Veränderungen der Inspektionsparameter beobachtet werden und somit kann festgestellt werden, ob diese Änderungen eine Verbesserung oder Verschlechterung bewirken.
• – Durch die Softwarestruktur ist es prinzipiell möglich, auch von räumlich weit entfernten Orten (im Fall von Fernwartung oder Teleservice) auf die Daten in Form von Kopien zuzugreifen, ohne die Leistung und Zuverlässigkeit der Inspektionen zu beeinträchtigen.

According to a preferred embodiment, the sensor structure of the device according to the invention comprises a network camera or a high-speed camera which has an image acquisition rate of up to 200 or 300 Hz. Furthermore, pulsed LED illuminations with a bright field and dark field illumination are provided, which can be controlled separately in their intensity. The flashing of the LED illumination and the image acquisition can be triggered by a light barrier. The photocell trigger signal can also be connected to the input / output card. In parallel inspection with a first parameterization and a second virtual parameterization, special requirements arise from the high production rate, without impairing the reliability of the fully automatic testing with the first parameterization. The concept of multithreading / multitasking software provides through the hierarchy of tasks or priorities and the ability to keep tasks and data (images, inspection areas with associated inspection criteria) as copies in memory and to modify or execute these copies independently (tasks) , several advantages:

• - The system can work with already tested or proven inspection parameter sets, while a user simultaneously creates or changes additional inspection parameter sets during production. In order to test the practicability of the setting, copies of the camera images are used, which the automatic task makes available to the parameterization task. On the other hand, one can load a picture or a plurality of pictures which the system has stored in the past on the hard disk and then tests the changed / existing parameter sets. Production is not jeopardized because all subtasks of the automatic task always have the highest priority and only then other tasks or tasks with a lower priority are executed. Furthermore, the integrity of the important data is guaranteed since only the copies of data records are used.
• - In addition, you can without significant loss of time (a few milliseconds) replace the copies of records (inspection parameters, inspection areas). This offers the possibility that (without stopping the production) parameters are changed. Thus, the system is real-time capable.
• - If the copies of the camera images are fed into the parameterization task, the effects of changes in the inspection parameters can be observed in parallel and thus it can be determined whether these changes cause an improvement or deterioration.
• - The software structure makes it possible in principle to access the data in the form of copies even from remote locations (in the case of remote maintenance or teleservice) without compromising the performance and reliability of the inspections.

Of the Statistical task can be both the current statistics data for example the last 24 hours as well as the statistics of the last days, months, Process and display years (offline statistics). The ad of tables / graphs (trend curves) or distribution maps to which Positions arising on the cover error clusters, can be parallel be made, i. in addition to the current statistics can also the statistics from an earlier one Time to be compared.

The Loading, saving, deleting and changing Data on the hard disk is also created as a task. No Performance issues with the comparatively slow disk operations too have the data created in small packages and then written on hard disk. This task has a low priority. Further the data is in a copy to capture data that while otherwise not recorded in a data operation. The copy is regarding the Complete record while the production data is written in a current record. Thus, the consistency of the data is always given and there is none Risk that inspection results by transferring memory to hard disk or vice versa can be lost or the inspection performance impaired becomes.

Consequently discloses a method and apparatus for optically examining test objects described. This involves taking at least one picture of the test object of at least one camera and an automated evaluation of the Camera images by means of an image evaluation unit connected to the camera using calculation methods, the ones transmitted by the camera Images through the image evaluation unit by means of a first active Parameterization, which for the assessment of the test object is used to be checked and where the test results are based on the first parameterization of a result output device be output, and being parallel to the image analysis with the first active parameterization of a user a second Parameterization is made and the camera images through the Image evaluation unit can be checked by means of the second parameterization, and where the test results based on the second parameterization of the result output device and without interruption of the test Image evaluation unit can be operated such that the second Parameterization for the assessment of the test objects while of the test run is used as active parameterization and the first parameterization becomes inactive.

Claims (10)

Method for optically checking test objects which have a relative speed, in particular by a transport device, with the following steps: taking at least one image of the test object from at least one camera, and automated evaluation of the camera images by means of an image evaluation unit connected to the camera by means of calculation methods, wherein the images transmitted by the camera are checked by the image evaluation unit by means of a first active parameterization, which is used for the evaluation of the test object, and wherein the test results are output from a result output device based on the first parameterization, and wherein the image evaluation is performed in parallel with the image evaluation first active parameterization by a user a second parameterization is made and the camera images through the image evaluation unit and the test results are displayed based on the second parameterization by the result output device, and wherein the image evaluation unit is operated without interruption of the test such that the second parameterization for the evaluation of the test objects during the test run used as an active parameterization and the first parameterization becomes inactive. Method according to claim 1, characterized in that that the test objects according to the assessment the active parameterization as a committee or non-committee become. Method according to claim 1 or 2, characterized that change the second parameterization via a data connection, in particular a network connection or an Internet connection, fed into the image evaluation unit becomes. Method according to one of claims 1 to 3, characterized that the test objects based on the assessment of the test results the image evaluation unit are discarded. Device for optical inspection of test objects, which in particular have a relative speed by a transport device, in particular for implementation the method according to a the claims 1 to 4, with at least one camera for recording at least a picture of the test object, one Illumination device for illuminating the surveillance area of the camera, and at least one image evaluation unit for automatic evaluation the camera images with the help of calculation methods, which with connected to the camera, being transmitted by the camera Images through the image evaluation unit by means of a first active parameterization, which for the assessment of the test object is used to be checked and where the test results are based on the first parameterization of a result output device be spent and being parallel to the image analysis with the first active parameterization of a user one second parameterization is made and the camera images through the image evaluation unit is checked by means of the second parameterization, and where the test results based on the second parameterization of the result output device being represented, and without interruption of the test Image evaluation unit is operated such that the second parameterization for the Assessment of the test objects while of the test run is used as active parameterization and the first parameterization inactive becomes. Device according to claim 5, characterized in that that a network camera is provided which with a computer is connected, in particular, a plurality of CPU cores or more CPU cores virtually replicates. Apparatus according to claim 5 or 6, characterized that a high-speed camera, preferably a camera with Gigabit Ethernet technology, which provides an image capture rate from 50 to 300 Hz, in particular substantially 100 to 200 Hz. Device according to one of the preceding claims 5 to 7, characterized in that the illumination device pulsed LED diodes, which in particular a bright field and dark field illumination produce. Device according to claim 8, characterized in that that a light barrier is provided to the flashing of the LED lighting and trigger the image capture. Device according to one of the preceding claims 5 to 9, characterized in that an ejection device is provided is which those test objects which of the image evaluation unit classifies as scrap become.