DE102017203391A1 - Method and coordinate measuring machine for the metrological measurement of workpieces with the aid of a light table - Google Patents

Abstract

The invention relates to a method 2 for metrological measurement of workpieces 3 by means of a coordinate measuring machine 1 with an optical sensor 7 for acquiring image information of at least one workpiece 3 to be measured, wherein the coordinate measuring machine 1 is equipped with a display 13 as part of a light table 11, wherein during the measurement and / or subsequently at the output of the measurement results, the at least one workpiece to be measured 3 rests on the display 13 of the coordinate measuring machine 1 and wherein during the measurement, the display 13 for illuminating the at least one workpiece 3 to be measured and / or wherein after the measurement the display 13 is controlled to display the measurement results of the at least one workpiece 3 to be measured. The invention further relates to a coordinate measuring machine 1 comprising a light table 11 for generating a field to be illuminated 15 and an optical sensor 7 for metrological measurement of at least one workpiece 3, wherein the field to be illuminated 15 of the light table 11 is temporally and spatially selectable variable and wherein the light table eleventh a display 13 as part includes.

Description

The invention relates to a method and a coordinate measuring machine for the metrological measurement of workpieces with the aid of a light table.

Illuminated tables for different applications are for example US 5,327,195 . US 5,347,342 . US 2006/0030026 . US 2006/0237658 . US 2007/0069643 . US 2008/0308752 and US 8,562,802 B1 known. In the published patent application US 2006/0030026 It is disclosed that LED light sources for collimating the light emitted by the light sources can be equipped with lenses. On the other hand, without any collimation in the published patent applications US 2007/069643 and US 2006/0237658 only the remote field homogeneously illuminated by a grid of LED light sources is used as a field for the light tables, resulting in a high space for these light tables.

In optical metrology, the vertical shadow cast of an object on a sensor or camera chip is evaluated for many applications. For this purpose, in a recorded by a camera chip image of an object to be measured or workpiece, the black and white transition with the location of edges of the workpiece is associated. By calibrating the optical measuring technique used based on reference objects or gauges such a connection between the black and white transition in the image and the real edge position at the object can be produced.

However, the basic prerequisite is that the shadow, ie the light and dark areas in the recorded image, actually corresponds to the profile of the measurement object. Optical systems, which are to be used for metrological purposes, not only have high demands on the imaging system, but also on the lighting system. Therefore, ideally, the lighting is adapted to the imaging system for the best possible results.

For metrological purposes, a telecentric imaging optics is typically used, so that a possibly incorrectly set working distance between the imaging optics and the workpiece to be measured is not reflected in the measurement error of the measurement. As a rule, an associated illumination optics will then also be realized as a telecentric illumination optics. A telecentric illumination optics here is an optic whose illumination light is directed, i. collimated, impinging on the workpiece to be measured, wherein the direction of the illumination light is aligned parallel to the direction of the optical axis of the telecentric imaging optics, if no optical deflecting elements are used.

The use of an adapted to the imaging system illumination optics, however, can not always be realized. Reasons for this include, inter alia, that an equally complex lighting system is reflected accordingly in the space and cost structure, since in addition to the imaging system, a second, complete optical system must be installed in a coordinate measuring machine. As a cost-effective alternative, therefore, the telecentric imaging optics and the telecentric illumination system are generally designed to be movable relative to the light table, so that both optical systems can be moved synchronously to the measurement of a workpiece along this workpiece. As a result, large-sized and therefore expensive optics for correspondingly large light tables are avoided.

As another alternative solution, however, often a light table is used, which can be built very flat and also cost-effective by the use of diffused LED light. It is therefore dispensed with the advantage of a telecentric lighting due to the cost and space. However, this measure is then at its technical limits when it comes to components with parallel or curved surfaces to the beam path, such as. to measure a lying cylinder. Due to the diffused LED light, reflections of the diffuse transmitted light are directed into the imaging optics and recorded on the chip, which leads to measurement errors. The "shadow cast" then no longer corresponds to the real profile of the measurement object.

Another problem with all lighting systems and light tables occurs in particular when measuring several workpieces. Often it is difficult for the user of the coordinate measuring machine to make an unambiguous assignment or a unique combination of the real workpieces on the light table with the representation of the workpieces on the monitor of the evaluation of the coordinate measuring machine. In general, this linkage must be accomplished by the user himself, by transferring the display on the monitor in his head in the correct orientation and the correct position of the real workpieces, so as for example, on the monitor detected as defective workpiece also on to identify the light table of the coordinate measuring machine.

In addition, in the measurement of multiple workpieces, the problem is that the signal to noise ratio at the detector or sensor by too much light of the light table from the Gaps between the workpieces is reduced.

The object of the invention is therefore to provide a simple and cost-effective method for metrological applications and a corresponding coordinate measuring machine with a light table, with the aim, especially in the measurement of multiple workpieces to reduce the necessary for the measurement of local light amount of the light table to a minimum and / / or after a successful measurement of a plurality of workpieces, marking the workpieces on the light table with information about at least one workpiece.

This object is achieved by a method for metrological measurement of workpieces by means of a coordinate measuring machine with an optical sensor for acquiring image information at least one workpiece to be measured, the coordinate measuring machine is equipped with a display as part of a light table, wherein during the measurement and / or subsequently during the output of the measurement results, the at least one workpiece to be measured rests on the display of the coordinate measuring machine and during the measurement the display for illuminating the at least one workpiece to be measured and / or after measurement the display for displaying the measurement results of at least one to be measured Workpiece is controlled.

In the context of this invention, a display is understood to be a TFT, LCD or OLED display, etc., as used for the known use in mobile phones and / or tablets and / or PC monitors.

According to the invention, it was recognized that the display of a mobile phone and / or a tablet and / or a PC can generate a sufficient amount of light for illuminating workpieces and in particular for illuminating the outer contours of workpieces. Furthermore, it has been recognized that the pixels of such a display can be controlled individually, so that, for example, no light is emitted from the interspaces between the workpieces in the simultaneous measurement of multiple workpieces, thereby increasing the signal-to-noise ratio of the CMM sensor improve with such measurements. In addition, a display offers the flexibility, in particular over a conventional light table, that certain workpieces and / or their geometric features can be marked or displayed by the display after the measurement.

• - Erfassen oder Vorgeben mindestens einer ersten Übersichtsbildinformation des mindestens einen Werkstücks;
• - Definieren eines Lichthofs zur Beleuchtung der Außenkontur des mindestens einen Werkstücks;
• - Erzeugen eines Lichthofs durch Ansteuerung des Displays;
• - Erfassen mindestens einer zweiten Bildinformation des mindestens einen Werkstücks;
• - Ermitteln von Kanteninformationen bezüglich des mindestens einen Werkstücks anhand von Bildinformationen; und
• - Vergleichen der aus den Kanteninformationen gewonnenen geometrischen Merkmale des mindestens einen Werkstücks mit den in einem Prüfplan hinterlegten geometrischen Merkmalen.

In one embodiment of the method according to the invention, the method comprises the following steps:

• Detecting or specifying at least one first overview image information of the at least one workpiece;
• - Defining an atrium to illuminate the outer contour of the at least one workpiece;
• - generating an atrium by driving the display;
• - Detecting at least a second image information of the at least one workpiece;
• - Determining edge information regarding the at least one workpiece based on image information; and
• - Comparing the obtained from the edge information geometric features of the at least one workpiece with the stored in a test plan geometric features.

By first acquiring overview image information about the at least one workpiece or predefining existing data such as CAD data, on the basis of this overview image information, an atrium around the outer contour of the workpiece can be defined, which is sufficient for a measurement of the workpiece by means of the coordinate measuring device , Subsequently, this halo can be generated by driving corresponding pixels of the display and it can be a second image information about the workpiece, the actual measurement information, won. Subsequently, the image information can be examined by means of standard libraries or standard methods for edge detection with regard to the position of the edges of the at least one workpiece. Finally, the geometric features of the at least one measured workpiece obtained from the edge information can be compared with the setpoint values of the geometric features stored in a test plan, including the tolerances of the workpiece stored there. Such an inventive method thus allows the target / actual comparison of workpieces and thus quality assurance of production processes.

In a further embodiment, the method according to the invention comprises the step of displaying the at least one workpiece in tolerance and / or out of tolerance by means of the display. This has the advantage that, especially in the simultaneous measurement of several workpieces, the faulty workpieces whose geometric features lie outside the permissible tolerance and stored in the test plan are displayed. As a result, the error-prone adjustment of the user between the representation of the defective parts on the monitor of the coordinate measuring machine and the real workpieces on the light table of the coordinate measuring machine is omitted for several workpieces.

In an embodiment, the method according to the invention comprises the step of outputting at least one geometric feature of the at least one workpiece by means of the display. As a result, important geometric features can be displayed directly on the workpiece for the user. A risk of confusion of the workpieces or a transmission error from the monitor of the coordinate measuring machine to the real workpiece can thus be excluded.

In a further embodiment of the method according to the invention, an area of the display which is not necessarily contiguous to be illuminated is defined in the definition of an atrium, preferably from +1 mm to -1 mm in the direction of the normal of the outer contour of +5 mm to -5 mm the outer contour obtained from the overview image information extends. As a result, unnecessary light between the workpieces in the measurement of multiple workpieces is avoided.

In one embodiment of the method according to the invention, during the detection of the at least one second image information of the workpiece during the generation of the atrium, the memory of the sensor is read out several times and the second image information is obtained by merging and / or joining the individual memory information generated therefrom. Such a second image information generated by means of stitching or mosaicing considerably reduces the scattered light component within the second image information since the exposure time is limited for individual regions of the second image information in comparison to the time for the generation of the entire second image information.

Alternatively, in another embodiment, during the detection of the at least one second image information of the workpiece during the generation of the atrium, the memory of the sensor is read out several times and the edge information of the workpiece is obtained from the individual memory information generated therefrom by merging and / or joining the individual ones thereof Edge information gained.

In one embodiment of the method according to the invention, geometrical features of the workpiece are determined automatically based on the obtained edge information or by request of the user. This enables quality assurance since e.g. In accordance with a test plan, the geometric features of the workpiece of interest for quality assurance are determined automatically and made available for further evaluations. Alternatively or additionally, such a selection of geometrical features can also take place through interaction of the user.

The present object is further achieved by a coordinate measuring machine comprising a light table for generating a field to be illuminated and an optical sensor for metrological measurement of at least one workpiece, wherein the field to be illuminated of the light table is temporally and spatially selectable variable and wherein the light table comprises a display as part. As already mentioned above, it has been recognized according to the invention that the individual controllability of the individual pixels of a display makes it possible to use such a display for targeted illumination of the outer contours of workpieces and / or for displaying workpieces during the measurement of workpieces by means of a coordinate measuring machine.

In one embodiment of the coordinate measuring machine according to the invention, the display is a color display, whereby form deviations of the at least one workpiece can be displayed out of tolerance with a specific color illumination of the workpiece. This makes it possible, for example, already mark a defective workpiece lying on the light table of the CMM in the color red, so that an immediate sorting is ensured by the user of the CMM with a very low risk of confusion.

In a further embodiment of the coordinate measuring machine according to the invention, the display displays at least one geometric feature and / or its deviation from a desired value of the geometric feature of the at least one workpiece as a numerical value in the immediate vicinity of the location of the workpiece on the display for viewing by the user of the coordinate measuring machine. As a result, the actual values of the geometric features of the workpieces can be displayed directly on or below the real workpieces on the display. Thus, the user receives information about the measured geometric features directly through the display and, additionally or alternatively, the deviation of the geometric features from the desired setpoint values of the workpieces can be output. This has the immediate advantage that an otherwise necessary viewing of the monitor of the coordinate measuring machine is eliminated and that the user thus receives a feedback on the quality of the workpieces directly during manual loading and unloading of the coordinate measuring machine.

In one embodiment of the coordinate measuring machine according to the invention, the display is designed such that the illumination light the field to be illuminated almost vertically leaves, wherein the local gravity angles of the illumination light in this case deviations from the perpendicular with respect to the field to be illuminated of less than 5 °, preferably less than 2 °. As a result, a telecentric or vertical illumination of workpieces is ensured.

In a further embodiment of the coordinate measuring machine according to the invention, the maximum local aperture angles of the illumination light when leaving the field to be illuminated deviate with respect to the associated local centroid beam angle of less than 5 °, preferably less than 2 °. As a result, a homogeneous or aligned as possible parallel illumination angle distribution is ensured.

In one embodiment of the coordinate measuring machine according to the invention, the light table comprises a Lammellenfilter for aligning the illumination light of the display, said Lammellenfilter is configured by a film. Film-Lammellenfilter are a cost-effective measure to align lighting light on the one hand and on the other hand to homogenize in its angular distribution or to parallelize.

Further features and advantages of the invention will become apparent from the following description of exemplary embodiments of the invention with reference to the figures, the essential details of the invention show, and from the claims. The individual features can be realized individually for themselves or for several in any combination in a variant of the invention.

• 1 eine schematische Darstellung eines Koordinatenmessgeräts des Standes der Technik;
• 2 eine schematische Darstellung eines erfindungsgemäßen Koordinatenmess geräts;
• 3 eine schematische Darstellung einer ersten Übersichtsbildinformation eines zu vermessenden Werkstücks;
• 4 eine schematische Darstellung eines Lichthofs um das zu vermessende Werkstück;
• 5 eine schematische Darstellung einer zweiten Übersichtsbildinformation eines zu vermessenden Werkstücks bei Nutzung eines Displays zur Beleuchtung;
• 6 eine schematische Darstellung der Anzeige eines vermessenen Werkstücks in Toleranz und / oder außer Toleranz sowie der Anzeige mindestens eines geometrischen Merkmals des vermessenen Werkstücks; und
• 7 eine schematische Darstellung einer Ausführungsform des erfindungsgemäßen Verfahrens.

Embodiments of the invention will be explained in more detail with reference to FIGS. In these shows

• 1 a schematic representation of a coordinate measuring machine of the prior art;
• 2 a schematic representation of a coordinate measuring device according to the invention;
• 3 a schematic representation of a first overview image information of a workpiece to be measured;
• 4 a schematic representation of a halo around the workpiece to be measured;
• 5 a schematic representation of a second overview image information of a workpiece to be measured when using a display for lighting;
• 6 a schematic representation of the display of a measured workpiece in tolerance and / or out of tolerance and the display of at least one geometric feature of the measured workpiece; and
• 7 a schematic representation of an embodiment of the method according to the invention.

1 shows purely by way of example a coordinate measuring machine 1a of the prior art. This coordinate measuring machine 1a includes a light table 11a with multiple light sources 13a , an imaging optics 5 and a sensor 7 , usually a CCD or CMOS chip. By means of the diffuse illumination light of the light table 11a is in 1 a workpiece 3 illuminated. It is based on the 1 clearly recognizing that not only perpendicular to the light table 11a emerging light rays 9 the light table 11a leave, but also dashed lines of light, which leave the light table obliquely. These emerging at an oblique angle light rays of the illumination light now lead just in three-dimensional objects as a workpiece 3 , such as one in 1 drawn sphere, to that to be measured outer contour of the workpiece 3 as a shadow not clearly as a light-dark transition through the imaging optics 5 on the sensor 7 is shown. The outer contour of in 3 exemplified ball 3 is washed out by the exiting at an oblique angle lighting rays so to speak, it occurs in the image of the shadow cast on the sensor 7 a very large area over many pixels of the sensor 7 light-dark transition taking place. Such a large-area light-dark transition is inherently subject to a large measurement error with regard to the outer contour to be determined as an edge in the image data. Accordingly, in coordinate measuring machines of the prior art for measuring the outer contour of three-dimensional workpieces often a so-called telecentric illumination is used, in which the light beams are aligned perpendicular to the field to be illuminated of the light table. However, such telecentric luminescent tables usually require complex optics for the alignment of the light, which in particular require large amounts of space for large illuminated tables and also cause very high costs.

The 2 now shows an example of a coordinate measuring machine according to the invention 1 for taking image information of a workpiece 3 by means of an imaging optics 5 and a sensor 7 , In the coordinate measuring machine according to the invention 1 includes the light table 11 at least one display 13 for lighting and / or displaying workpieces 3 , In this display 13 the coordinate measuring machine according to the invention 1 It is a typical TFT, LCD or OLED display, etc., as used in cell phones and / or tablets and / or PCs. Furthermore, the Light table 11 a field to be illuminated 15 or the light table 11 has such a field to be illuminated 15 for lighting on the light table 11 stationary workpieces 3 on. The light 9 of the display 13 is represented by an optional Lammellenfilter shown 17 of the light table 11 aligned in parallel. Alternatively to the in 2 illustrated embodiment, the light table 11 the coordinate measuring machine according to the invention 1 also only from the display 13 even exist or can the display 13 itself include such a Lammellenfilter for aligning the display light. As a rule, such is one in which 2 illustrated Lammellenfilter 17 designed to align the illumination light by two mutually crossed Lammellenfilterfolien. Such films are known from ATMs or even PC or laptop monitors for viewing angle restriction against unwanted viewers. The parallel aligned by said measures light 9 now allows the shadow cast of the in 3 exemplary as a workpiece 3 shown ball 3 on the sensor 7 also the actual outer contour of the sphere 3 equivalent. For complete detection of the entire outer contour of the sphere 3 it is only necessary to determine the outer contour as edge information from the detected light-dark transition of the image information.

The 3 schematically shows a first overview image information about a on the light table 11 the coordinate measuring machine according to the invention 1 located workpiece 3 , This overview image information of the workpiece 3 can in this case with the ambient light of the coordinate measuring machine and / or using the light table 11 be recorded. This in 3 represented workpiece 3 Here, by way of example only, this may be a ball attached to a tapered cylinder. The one of the workpiece 3 covered part of the light table 11 appears when using the light table 11 for illuminating the workpiece 3 as a shadow in the sensor 7 taken overview image information dark and is therefore in 3 hatched drawn. The uncovered part of the light table appears bright.

From the overview image information of the workpiece 3 The outer contour can now be obtained, for example, by obtaining from the acquired overview image information the edge profiles of the outer contour by means of known evaluations of the prior art from light-dark transitions to pixel information. This results point clouds in a plane as a record of the outer contour. Alternatively, the point clouds of the outer contours can be generated according to software technology from the overview image information specified by a CAD data record or a test plan.

4 now shows schematically a second image information, with the inventive method 2 or coordinate measuring machine 1 has been recorded. This second image information gives the shadow cast of the workpiece 3 analogous to 3 again, taking care of the outer contour of the workpiece 3 or the limitation of the Schattenwurfs one in the 4 brightly illustrated atrium 23 extends. However, in 4 strictly speaking, only a part of the generated halo 23 shown, since the real halo created 23 to below the workpiece 3 extends. This ensures that the outer contour of the workpiece 3 also completely illuminated for a survey. In this respect, a real atrium 23 which is slightly larger than the atrium reproduced in the second image information 23 of the 4 the sensor 7 can record. The remaining area of the light table 11 outside the atrium 23 is obtained in obtaining the second image information according to the in 4 not lit and therefore remains dark. Thus, this part of the light table 11 also like the workpiece 3 hatched in the representation of the second image information in 4 located.

As a necessary atrium with a certain minimum depth of the atrium 23 is here in connection with the 4 a not necessarily contiguous to be illuminated surface portion of the light table 11 understood, which extends from + 5 mm to - 5 mm preferably from +1 mm to - 1 mm in the direction of the normal of the outer contour to the outer contour obtained from the overview image information.

The 5 indicates alternatively 4 schematically the case of a second image information obtained with the inventive method 2 or coordinate measuring machine 1 in the creation of an extended halo 23 for illuminating a workpiece 3 has been recorded by the light table 11. Such an extended halo 23 of the 5 can reach the edge of the field to be illuminated 15 of the light table 11 extend. Extended halos 23 are especially necessary if new workpieces are always needed 3 For example, as part of a quality control embedded in the manufacturing process, it should be checked and it is not ensured that the workpieces 3 be placed again and again with a high accuracy at the same position on the light table. By means of these extended halos can thus be ensured that the outer contour of the light table 11 stored workpieces 3 is sufficiently illuminated for a measuring operation, even if the overview image information of the stored workpiece 3 not previously recorded, but is predefined by, for example, prefabricated inspection plans.

The 6 schematically shows the display of a workpiece 3 on the light table 11 through the display 13 from the perspective of the user in the plan view, the workpiece 3 here on the light table 11 of the coordinate measuring machine 1 rests. In the case of another embodiment in which the light table 11 only from the display 13 when the workpiece rests 3 then directly on the display 13 , The display of the workpiece 3 or the representation of the measurement results of a workpiece 3 can now be that this for visualization for the user in the case of a component out of tolerance by a halo 19 is illuminated. Alternatively, workpieces can also be used 3 in tolerance with a corresponding atrium 19 are displayed. Additionally or alternatively, these halos can 19 in a color display also be held in different colors, depending on whether the workpiece 3 after the measurement is considered within or outside the tolerance. As a display of a workpiece 3 or as a representation of the measurement results of a workpiece 3 may alternatively or in addition to a halo 19 also the representation of a numerical value (X) of at least one geometric feature ( 21 ) of the workpiece 3 on the light table 11 or display 13 serve. Such a representation of a numerical value (X) on the display can also be effected by specifying the unit of measure associated with the numerical value.

• - Erfassung 4 oder Vorgabe 4 mindestens einer ersten Übersichtsbildinformation des Werkstücks 3;
• - Definition 6 eines Lichthofs 23 zur Beleuchtung der Außenkontur des Werkstücks 3 anhand der aus der Übersichtsbildinformation gewonnenen Außenkontur des Werkstücks 3;
• - Erzeugen 8 des Lichthofs 23 durch das Display 13 des Leuchttischs 11;
• - Erfassung 10 mindestens einer zweiten Bildinformation des Werkstücks 3 während der Erzeugung 8 des Lichthofs 23; und
• - Ermitteln 12 von Kanteninformationen bezüglich des Werkstücks 3 anhand der mindestens einen zweiten Bildinformation.

The 7 schematically shows an embodiment of the method according to the invention 2 for the metrological measurement of workpieces 3 by means of a coordinate measuring machine 1 , wherein the coordinate measuring machine 1 a light table 11 for lighting workpieces 3 and an optical sensor 7 for acquiring image information of the workpiece 3 and wherein the method 2 the following steps:

• - Capture 4 or default 4 at least a first overview image information of the workpiece 3 ;
• - Definition 6 a halo 23 for illuminating the outer contour of the workpiece 3 based on the obtained from the overview image information outer contour of the workpiece 3 ;
• - Produce 8th of the atrium 23 through the display 13 of the light table 11 ;
• - Capture 10 at least a second image information of the workpiece 3 during production 8th of the atrium 23 ; and
• - Determine 12 of edge information regarding the workpiece 3 on the basis of the at least one second image information.

At step 4 of the procedure 2 of the 7 can the overview image information of the workpiece 3 according to 3 be obtained by a first image acquisition of the workpiece 3 by means of the sensor 7 the coordinate measuring machine is detected or by such an overview image information of the workpiece 3 for example, from a test plan of the workpiece 3 is given. It is only important here that the overview image information is such and in such a format that from this every point of the outer contour of the workpiece 3 plus its position and position on the field to be illuminated with an accuracy of better than 10 mm or 5 mm deviation from the actual actual position on the field to be illuminated 15 of the light table 11 can be recorded or specified. When acquiring the overview image information of the workpiece 3 It is also not necessarily necessary that the light table 11 acts as a light table or its light sources are turned on. A capture of the overview image information of the workpiece 3 by means of the sensor 7 from which the outer contour can be obtained with the sufficient accuracy described above, can also be achieved by the illumination of the workpiece 3 reach with ambient light, so that in this case to an active operation of the light table 11 can be waived.

Based on the obtained from the overview image information outer contour of the workpiece 3 on the field to be illuminated 15 of the light table 11 will then step in 6 of the method 2 of 7 a halo 23 Are defined. This is either in the definition 6 a halo 23 a not necessarily contiguous to be illuminated surface portion of the light table 11 defined, which extends from + 5 mm to - 5 mm, preferably from +1 mm to - 1 mm in the direction of the normal of the outer contour to the outer contour obtained from the overview image information. This type of definition of a halo 23 is useful for the reduction of stray light, if it is sufficiently certain that the deviation of the points of the assumed outer contour on the illuminated field of the light table 11 relative to the actual actual position is less than 5 mm or 1 mm. As a rule, this will then be fulfilled if the overview image information is based on a previously recorded image of the workpiece 3 on the light table 11 by means of the sensor 7 in step 4 was recorded.

When creating 8th of the atrium 23 according to step 8th of the procedure 2 of the 7 becomes the display 13 controlled accordingly. For this, the data about the stored and to be measured workpieces 3 used, if they have been obtained, for example, from the first overview image information. This ensures that one for the measurement of the outer contour sufficient illumination for the generation of a second image information is achieved.

During production 8th of the atrium 23 according to step 8th of the procedure 2 of the 7 will according to step 10 the method according to the invention at least a second image information of the workpiece 3 detected. This can either be done by capturing 10 the at least one second image information of the workpiece 3 during production 8th of the atrium 23 the exposure time of the sensor 7 is chosen such that the second image information by a single reading of the memory of the sensor 7 is won. This makes it possible to obtain a second image information of the workpiece immediately after completion of the measuring process, without having to stitch together or join together several image information of the workpiece by means of stitching or mosaicing. Any additional measurement error caused thereby is thus avoided.

Alternatively, when capturing 10 the at least one second image information of the workpiece 3 during production 8th of the atrium 23 the memory of the sensor 7 be read out several times and the second image information can be obtained by merging and / or joining the individual memory information generated therefrom. Such a second image information generated by means of stitching or mosaicing considerably reduces the scattered light component within the second image information since the exposure time is limited for individual regions of the second image information in comparison to the time for the generation of the entire second image information.

In addition, when capturing 10 the at least one second image information during the generation 8th of the atrium 23 of the procedure 2 of the 7 also more than a second image information of the workpiece 3 by means of the sensor 7 be detected by the described methods of image generation. This is indicated in particular when it is necessary to generate separate second image information for different regions of the outer contour.

In the next step 12 of the procedure 2 of the 7 the determination takes place 12 of edge information regarding the workpiece 3 on the basis of the at least one second image information. The investigation 12 the edge information of the workpiece 3 This can be done using standard methods for determining edge transitions in pixel information. This edge information is then available for further geometric evaluations.

For example, in one embodiment of the method 2 of the 7 automated based on the obtained edge information or determined by request of the user geometric features of the workpiece. As a result, a quality assurance of the production processes of the workpiece 3 allows, for example, according to a test plan automatically determines the interesting for quality assurance geometric features of the workpiece and made available for further analysis. Alternatively or additionally, such a selection of geometrical features can also take place through interaction of the user.

In the next step 14 of the procedure 2 of the 7 become the geometric features of the at least one workpiece obtained from the edge information 3 compared with the geometric features stored in a test plan. As a result, it can now be determined whether a workpiece was manufactured in tolerance or out of tolerance.

According to step 16 of the procedure 2 the Figure 7 can then do this in step 14 determined by comparison deviations of the at least one workpiece 3 in tolerance and / or out of tolerance by means of the display 13 are displayed. For example, here only the workpieces 3 out of tolerance with a halo 19 be provided. Alternatively, it is equally possible that only the workpieces 3 in tolerance with such a halo 19 be provided. When using a color display, the halos can 19 for the display of workpieces in tolerance and of workpieces except tolerance in different colors.

Alternatively or in addition to step 16 of the procedure 2 the Figure 7 can in step 18 of the procedure 2 of the 7 also the determined geometric features of the workpieces 3 or at least one geometric feature of at least one workpiece 3 by means of the display 13 be issued. As a result, the user is immediately below the real workpiece 3 the numerical value of at least one geometric feature of the workpiece 3 displayed in the immediate vicinity of the geometric conditions. Optionally, this is done with or without the associated unit of measurement of the numerical value.

The basis of 7 illustrated embodiment of the method according to the invention 2 is based as all other methods of the invention 2 for the metrological measurement of workpieces 3 by means of a coordinate measuring machine 1 with an optical sensor 7 for acquiring image information of at least one workpiece to be measured 3 on that the coordinate measuring machine 1 with a display 13 as part of a light table 11 is equipped, wherein during the measurement and / or subsequently at the output of the Measurement results the at least one workpiece to be measured 3 on the display 13 of the coordinate measuring machine 1 rests and that during the measurement the display 13 for illuminating the at least one workpiece to be measured 3 and / or that after the measurement the display 13 for displaying the measurement results of the at least one workpiece to be measured 3 is controlled.

It is therefore understood that the in 7 illustrated method 2 only a specific embodiment of the method according to the invention 2 is and that the inventive method 2 Thus, not on this specifically explained embodiment of 7 is restricted.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 5,327,195 [0002]
• US 5347342 [0002]
• US 2006/0030026 [0002]
• US 2006/0237658 [0002]
• US 2007/0069643 [0002]
• US 2008/0308752 [0002]
• US 8562802 B1 [0002]
• US 2007/069643 [0002]

Claims (14)

Method (2) for the metrological measurement of workpieces (3) by means of a coordinate measuring machine (1) with an optical sensor (7) for acquiring image information of at least one workpiece (3) to be measured, characterized in that the coordinate measuring machine (1) is equipped with a display ( 13) as part of a light table (11) is equipped, wherein during the measurement and / or subsequently in the output of the measurement results, the at least one workpiece (3) to be measured rests on the display (13) of the coordinate measuring machine (1) and that during the Measurement of the display (13) for illuminating the at least one workpiece to be measured (3) and / or that after the measurement, the display (13) for displaying the measurement results of the at least one workpiece to be measured (3) is driven. Method (2) according to Claim 1 the method comprising the steps of: - acquiring (4) or specifying (4) at least one first overview image information of the at least one workpiece (3); - Defining (6) an atrium (23) for illuminating the outer contour of the at least one workpiece (3); - generating (8) an atrium (23) by driving the display (13); - detecting (10) at least one second image information of the at least one workpiece (3); - Determining (12) of edge information regarding the at least one workpiece (3) based on image information; and - comparing (14) the geometric features of the at least one workpiece (3) obtained from the edge information with the geometric features stored in a test plan. Method (2) according to Claim 1 or 2 wherein the method comprises the step of: displaying (16) the at least one workpiece (3) in tolerance and / or out of tolerance by means of the display (13). Method (2) according to one of the preceding claims, the method comprising the step: - Output (18) of at least one geometric feature of the at least one workpiece (3) by means of the display (13). Method (2) according to Claim 2 wherein the definition (6) of an atrium (23) defines a not necessarily contiguous surface portion of the display (13) to be illuminated, preferably + 1 mm to -1 mm in the direction of Normal of the outer contour to the outer contour obtained from the overview image information extends. Method (2) according to Claim 2 wherein during the detection (10) of the at least one second image information of the workpiece (3) during the generation (8) of the atrium (23) the memory of the sensor (7) is read out several times and the second image information by merging and / or joining the individual storage information generated therefrom is obtained. Method (2) according to Claim 2 wherein during the detection (10) of the at least one second image information of the workpiece (3) during the generation (8) of the atrium (23) of the memory of the sensor (7) is read several times and the edge information of the workpiece (3) from the individual Memory information generated therefrom is obtained by merging and / or joining the individual edge information obtained therefrom. Method (2) according to Claim 2 , whereby geometrical features of the workpiece (3) are determined automatically based on the obtained edge information or by request of the user. Coordinate measuring machine (1) comprising a light table (11) for generating a field to be illuminated (15) and an optical sensor (7) for metrological measurement of at least one workpiece (3), wherein the field (15) of the light table (11) to be illuminated temporally and spatially is variably variable, characterized in that the light table (11) comprises a display (13) as a component. Coordinate measuring device (1) to Claim 9 wherein the display (13) is a color display (13) and deviations in shape of the at least one workpiece (3) are displayed out of tolerance with a certain color illumination of the workpiece (3). Coordinate measuring device (1) to Claim 9 or 10 in that the display (13) displays at least one geometric feature of the at least one workpiece (3) as a numerical value in the immediate vicinity of the location of the workpiece (3) on the display (13) for viewing by the user of the coordinate measuring machine (1). Coordinate measuring device (1) according to one of Claims 9 to 11 wherein the display (13) is designed such that the illumination light (9) leaves the field (15) to be illuminated almost perpendicularly, the local centroid angles of the illumination light thereby deviating from the vertical with respect to the field (15) to be illuminated of less than 5 °, preferably less than 2 °. Coordinate measuring device (1) to Claim 12 , wherein the maximum local opening angles of the illumination light (9) when leaving the to be illuminated field (15) have a deviation with respect to the associated local gravity jet angle of less than 5 °, preferably less than 2 °. Coordinate measuring device (1) according to one of Claims 9 to 13 wherein the light table (11) comprises a Lammellenfilter for aligning the illumination light of the display (13) and this Lammellenfilter is designed as a foil.

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