DE102016105426B4 - Optical measuring system and optical measuring method - Google Patents

Abstract

Optical measuring system (1) having a signal unit (10) which is designed to emit a signal light beam (10a) onto an object surface (30) to be measured, and with an optical detection unit (11) which is formed from the object surface (10). 30) reflected signal light beam (10b) together with a surrounding object area (11b), wherein the optical detection unit (11) comprises a first optical sensor (12) which is formed, the reflected signal light beam (10b) together with the surrounding object area ( 11b) on a first optical path (12a), wherein the optical detection unit (11) further comprises a second optical sensor (13), which is formed, the reflected signal light beam (10b) together with the surrounding object area (11b) on a second optical path (13a), and wherein the optical detection unit (11) further comprises an optical filter (15), which in the second op Table (13a) between the object surface to be measured (30) and the second optical sensor (13) is arranged and configured to filter out the reflected signal light beam (10b) from the second optical path (13a) and surrounding the reflected signal light beam (10b) An object region (11b), characterized by a data processing unit (16) which is designed to obtain first image data of the first optical path (12a) and second image data of the second optical path (13a), wherein the data processing unit (16) is further formed, to generate a difference image from the first image data and from the second image data.

Description

The present invention relates to an optical measuring system according to the preamble of claim 1 and to an optical measuring method according to claim 7.

In manufacturing technology, various processing methods are known in which the tool is guided relative to the workpiece. For processing methods such. As the milling, welding, laser or plasma jet cutting while the tool such. As a router, a welding or cutting head as a machining head z. B. a machine tool or a production robot guided relative to the workpiece to be machined. Here, usually a given trajectory, d. H. a time-dependent course of a location, traveled by the tool to perform on the workpiece machining. A trajectory can also be referred to as a path, path or path.

This departure of the given trajectory by means of the tool usually expires automatically. There is a risk that a collision of the tool along the trajectory can occur if there is an obstacle in this area. As such obstacles come z. B. Spanungsrückstände, broken workpiece parts or other objects in question, which unintentionally z. B. in the working space of the machine tool and can get into the trajectory of the tool. Such a collision can lead to damage to the tool itself. Also, the tool can be at least temporarily so diverted from its trajectory, so that it can lead to incorrect processing of the workpiece, which can be unusable. In any case, a collision can lead to costs due to damage, production losses or production delays.

In order to avoid such collisions between obstacle and tool, it is known to monitor the tool during its movement along the trajectory. Here, the area on the trajectory is usually monitored in front of the tool, so that an obstacle on the trajectory can be detected in time so that the processing can be stopped and a collision can be prevented. In this case, the monitoring is usually carried out immediately in front of the tool, however, at a sufficient distance to this, so that could respond to a detected obstacle in time.

For such process monitoring can be used as a measuring method for obstacle detection z. B. the method of laser light section are used, which is also known as laser triangulation. This z. B. by means of a line laser, a laser beam as a signal light directed to the monitored surface of the workpiece as a measurement object and the reflected laser light z. B. detected with a camera whose position and orientation relative to the laser beam source is known. If the distance of the measured object to the laser beam source or to the camera changes, the angle at which the reflected laser light is detected by the camera also changes. This changes the position of the image of the reflected laser light on the photoreceiver of the camera. From this change in position, the distance of the object to be measured from the laser beam source or from the camera can be calculated with the help of the angle functions. In other words, the distance between the laser beam source or camera and workpiece can be calculated by means of laser triangulation from the image position of the reflected laser beam. Alternatively, a deflection of the laser line relative to a desired position or reference position can be detected.

This metrologically determined distance or deviation to a desired position can be supplied to the process monitoring and compared there with a distance which is predetermined at this point of the trajectory. If the measured actual distance value deviates from the predefined setpoint distance value by a predetermined amount, then it can be concluded by the process monitoring of an obstacle on the trajectory in front of the tool. In response, the tool may be stopped or a detected obstacle may be bypassed to avoid a collision.

It is advantageous in the case of laser triangulation that purely trigonometric relationships are present, which can be quickly calculated and evaluated. The measurement can therefore be carried out continuously and is well suited for distance measurement on moving objects, in which z. B. a collision detection in real time with very short cycle times must be done so that z. B. the process monitoring or the machine tool can react quickly enough to a detected obstacle. It is also a non-contact measuring method, which makes the application simple and robust.

The disadvantage of laser triangulation, however, is that it can be disturbed very much by light. This can come into play, in particular, in processing methods which use light as a process light such. B. work in laser cutting or plasma welding. The process light can emit scattered light, which can be received by the camera of the measuring system. Also, in such processing method light z. B. caused by sparks. In these cases can no longer be sure between the to be detected by The laser light reflected from the object to be measured can be distinguished as a signal light and the disturbing light, which can be produced by directly emitted and reflected or scattered process light and / or by light from sparks or by flying sparks. In these cases, a reliable application of laser triangulation may no longer be possible.

Nevertheless, in order to be able to apply the laser triangulation as a measuring method to processing methods with stray light, it is for example from US Pat. No. 6,674,893 B1 It is known to arrange an optical filter in the form of a bandpass filter in front of the camera of the measuring system, which can only transmit the wavelengths of the signal light reflected by the measuring object. In this way, the portions of the disturbing light, which are outside the wavelength spectrum of the optical filter and differ from the wavelength of the signal light, can be kept away from the camera of the measuring system.

The disadvantage here, however, that the proportion of the disturbing light, which has the same wavelength as the signal light and thus can pass through the optical filter of the camera, can be large enough so that not enough or not distinguish between signal light and stray light from the measuring system can. Also, the intensity of the disturbing light may be greater than the intensity of the signal light, so that the disturbance light from the measuring system may be erroneously regarded as a signal light. In either case, the use of an optical filter in front of the camera can not achieve such filtering of the disturbing light to allow application of laser triangulation for such processing methods. As a result, a reliable application of the laser triangulation can be prevented.

In order to make the measurement method of laser triangulation more robust against stray light, it is possible to increase the intensity of the signal light in such a way that a clearer distinction between signal light and stray light can be achieved. However, this can greatly increase the complexity of the laser triangulation measurement method because a correspondingly strong source of the signal light must be used. Also, at high intensities of the signal light such. B. laser light additional protective measures for safety at work are required. Furthermore, it can not be reliably ruled out even at high intensity of the signal light that at least briefly stray light z. B. may occur due to sparks, which has a higher intensity than the signal light and thus can interfere with the measurement process.

An object of the present invention is to provide an optical measuring system and an optical measuring method of the type described above, so that the method of laser triangulation can be used in processing methods in which interfering influences can occur by stray light. At least an alternative to known measuring systems or measuring methods should be created.

The object is achieved by the features of the characterizing part of claim 1 and by the features of claim 7. Advantageous developments are described in the subclaims.

The present invention thus relates to an optical measuring system which operates by means of image processing. The optical measuring system has a signal unit which is designed to emit a signal light beam onto an object surface to be measured. The signal light beam may be, for example, a light beam of weak intensity, which z. B. by an LED, a laser diode or the like can be generated. Preferably, the signal light beam is a focused or collimated light beam with high local power density such. As a laser beam so that the optical detection and detection can be simplified within a visual scene by the high power density of the signal light beam.

The object surface to be measured can, for. B. be monitored workpiece surface in a machining process. The workpiece may preferably have a surface which favors a reflection of the signal light beam such. As a smooth, polished or polished surface. Preferably, alternatively or additionally, the material of the workpiece per se may be suitable for reflecting the signal light beam. This can be z. B. be the case with metallic materials.

The optical measuring system further has an optical detection unit, which is designed to detect the signal light beam reflected from the object surface together with a surrounding object area. The surrounding object area is to be understood as the area of the object surface which is arranged around the location or around the area at which or at which the signal light beam impinges on the object surface and is reflected.

The optical detection unit has a first optical sensor, which is designed to detect the reflected signal light beam together with the surrounding object area on a first optical path. An optical path is to be understood as the path of the light that the Light from a place such as B. from the object area of the object surface to another location such. B. travels the first optical sensor. On this first optical path, an image of the object area can thus be optically detected by the first optical sensor. In other words, the object region can also be understood as its optical image, which can be detected by an optical sensor as image or scene.

The present invention is characterized in that the optical detection unit further comprises a second optical sensor which is designed to detect the reflected signal light beam together with the surrounding object area on a second optical path. Furthermore, the optical detection unit has an optical filter which is arranged and configured in the second optical path between the object surface to be measured and the second optical sensor to filter out the reflected signal light beam from the second optical path and to pass the object region surrounding the reflected signal light beam.

According to the invention, two different images of the same scene of the object surface to be measured are taken in this way, namely an image with signal light and stray light on the first optical path and an image without signal light but with stray light on the second optical path. In other words, the reflected signal light beam and the object area can be detected by means of the first optical sensor, but only the object area by means of the second optical sensor because the reflected signal light beam has been filtered out of the second optical path by the optical filter in front of the second optical sensor.

In this way, two different images of an identical scene are provided, which are subtracted from each other. As a result, only the signal light remains essentially in the resulting difference image, whereas the disturbance light is canceled out and thus no longer exists in the difference image. This difference image can then be based on z. B. a laser triangulation using the signal light serve. The result of the laser triangulation can be used for process monitoring to detect an obstacle detection z. B. before a process light as a tool such. B. laser or plasma jet cutting perform.

In other words, according to the invention, stray light, which is used as z. B. may occur as scattered light from process light or light of sparks in certain processing methods, separated from the signal light, so that as a differential image z. B. the laser line of the signal light z. B. a laser triangulation remains.

As the signal light, preferably a line may be used, as is common in laser triangulation, to detect a distance change along the direction of the line. However, other signal light patterns are possible, even complex patterns, because the difference image generation can be performed independently of the signal light pattern used and each only substantially filters out the signal light from the visual scene, however the signal light will be.

Preferably, monochromatic signal light can be used so that the optical filter can be selected to filter out just more precisely this wavelength. The usually broadband stray light can pass as far as possible through the optical filter in this way, so that the greatest possible intensity of the stray light can be detected by the second optical sensor and used for the formation of the difference image. In this way, the stray light can be eliminated as completely as possible by the difference image generation in the detected scene.

It is advantageous here that the stray light can be recorded in this way with approximately the same intensity in both images of the same scene and then filtered out by the difference image generation with the same intensity from the difference image. Thus, the intensity of the disturbing light, which z. B. may vary in light of sparks, no effect on the measuring system according to the invention. This also applies to the wavelength of the stray light.

It is also advantageous that the difference formation of two images can be carried out very quickly and easily. In this way, a measurement according to the invention can be performed and evaluated very quickly, so that the difference image can be fed to a laser triangulation, which z. B. obstacle detection in the context of process monitoring. The process monitoring can then also be carried out very quickly, whereby the optical measuring system according to the invention or the process monitoring can be real-time capable, for. With 25 frames / second. In this way, the optical measuring system according to the invention may be suitable for use in fast processing methods.

The measuring system according to the invention can preferably be used for obstacle detection in machining processes, which can have stray light due to stray light from the process light or due to flying sparks. There are, however other metrological applications using the measuring system according to the invention possible such. B. the geometry measurement of an object such. B. a workpiece to be machined under such conditions.

According to one aspect of the present invention, the optical detection unit further comprises a beam splitter configured to split the reflected signal light beam together with the surrounding object area into the first optical path and the second optical path, the optical filter in the second optical path between the beam splitter and the second optical sensor is arranged. In other words, the two optical paths of the two optical sensors from the measuring object surface to the beam splitter are identical, so that the same object region of the workpiece can be optically detected as optically as possible with both optical sensors. In this way, the two images that are generated by the two optical sensors, the same scene as possible, so that the two images lie as ideally as possible when subtracting each other. In other words, an offset of the two images can be avoided to one another, which would otherwise have to be corrected by additional effort before the difference in the image processing and otherwise could affect the extinction of the stray light by subtraction.

According to another aspect of the present invention, the optical filter is a band stop filter configured to filter out the wavelength of the reflected signal light beam from the second optical path. Such an optical filter is also known as a notch filter. As a result, the signal light beam blocked, but all other wavelengths are allowed to pass, so that the object area including Störlicht can be optically detected by the band reject filter.

The signal light preferably has the narrowest possible wavelength range and the band stop filter is tuned as precisely as possible to this wavelength range, so that the signal light can be filtered as completely as possible and the disturbance light can be transmitted as completely as possible through the band stop filter. This can improve the effect of the difference formation, which are as identical as possible to the detected images of the two optical sensors except for the filtered signal light beam filtered out by the band stop filter.

According to a further aspect of the present invention, the first optical sensor and / or the second optical sensor is / are a camera, in particular a high-speed camera. By means of a camera, a simple and cost-effective implementation of an optical sensor can take place, which can also be used simply in the context of image processing.

Preferably, a high-speed camera can be used as the camera. As a result, the acquisition of the images can be accelerated, so that a fast processing of the images can be made possible. This can enable the real-time capability of process monitoring even at higher processing speeds, so that the differential image for laser triangulation can also be used in such applications.

According to another aspect of the present invention, the optical detection unit further comprises a data processing unit configured to obtain first image data of the first optical path and second image data of the second optical path, the data processing unit being further constructed of the first image data and the first image data second image data to generate a difference image.

The data processing unit may be present as a separate hardware unit within the optical detection unit or as a component of one of the two cameras. Alternatively, the data processing unit may also be a separate hardware unit outside the optical detection unit. Alternatively, the data processing unit can also be realized and implemented as software.

By means of the data processing unit, a processing of the two images of the same scene can be carried out in such a way that they are subtracted from one another so that a difference image remains, which essentially can only have the signal light. As a result, the use of the image data of the two optical paths for filtering out the interfering light by means of subtraction within the optical detection unit.

According to another aspect of the present invention, the data processing unit is further configured to perform a triangulation method based on the difference image. This can enable the use of difference formation for distance determination by means of the optical detection unit. The distance determined in this way can z. B. a laser triangulation with a process monitoring for obstacle detection are supplied.

According to another aspect of the present invention, the second optical sensor and / or the data processing unit is / are formed, and the image data of the second optical path is brightness matched perform. This may be advantageous because not only the reflected signal light beam from the second optical path can be filtered out by the optical filter, but also portions of the remaining image data such. B. the stray light, which correspond to the wavelength of the signal light beam. This can be compensated for again by adjusting the brightness of the image of the second path, so that once the brightness is matched, two images that are as identical as possible are available with regard to the intensity of the components of the disturbing light. Their difference can then lead to the most effective possible elimination of the stray light and thus formation of the signal light.

It is advantageous that a brightness adjustment in the context of image processing with little computational effort may be possible, so that thereby continue the real-time capability and applicability of the optical measuring system according to the invention z. B. in machining processes at high speeds z. B. can remain given for process monitoring.

• • Aussenden eines Signallichtstrahls auf eine zu messende Objektoberfläche,
• • Rücksenden eines von der Objektoberfläche reflektierten Signallichtstrahls zusammen mit einem umgebenden Objektbereich auf einem ersten optischen Pfad und auf einem zweiten optischen Pfad,
• • Herausfiltern des reflektierten Signallichtstrahls aus dem zweiten optischen Pfad, und
• • gleichzeitiges Erfassen des ersten optischen Pfads als erste Bilddaten und des zweiten optischen Pfads als zweite Bilddaten und Erzeugung eines Differenzbildes aus den ersten Bilddaten und aus den zweiten Bilddaten.

The present invention also relates to an optical measuring method comprising the steps of:

• Emitting a signal light beam onto an object surface to be measured,
• Returning a signal light beam reflected from the object surface together with a surrounding object region on a first optical path and on a second optical path,
• • filtering out the reflected signal light beam from the second optical path, and
• Simultaneously detecting the first optical path as first image data and the second optical path as second image data and generating a difference image from the first image data and from the second image data.

By means of the optical measuring method according to the invention, which can be implemented, for example, with the optical measuring system according to the invention described above, a scene, namely the signal light beam reflected by the object surface together with a surrounding object area, can be optically detected twice. However, from the second optical path, the reflected signal light beam may be filtered out so that the filtered image data of the second optical path has only the detected object area transmitted through the filtering. These two image data are, as described above, used for a difference, the result of which only has the signal light beam, but no longer the disturbance light.

• • Teilen des reflektierten Signallichtstrahls zusammen mit dem umgebenden Objektbereich in den ersten optischen Pfad und in den zweiten optischen Pfad.

According to one aspect of the present invention, the optical measuring method between the step of returning and the step of filtering out further comprises the further step:

• • Splitting the reflected signal light beam together with the surrounding object area into the first optical path and into the second optical path.

In this way, a separation of the two paths can be made so that they show as possible an identical view of the scene, but can be separated before reaching the two optical sensors in the respective optical paths.

• • Anpassen der Helligkeit der zweiten Bilddaten des zweiten optischen Pfads.

According to one aspect of the present invention, the optical measuring method further comprises, after the step of simultaneously detecting, the further step of:

• • Adjust the brightness of the second image data of the second optical path.

In this way, a reduced brightness of the second image, which can occur through the optical filtering, at least partially, preferably as completely as possible, be compensated again, so that two identical images as possible with respect to the Störlichtanteile can be used to form the difference.

An embodiment and further advantages of the invention are explained below in connection with the following figures. It shows:

1 a schematic side view of an optical measuring system according to the invention in a processing method with process light;

2 a schematic side view of an optical detection unit of the optical measuring system according to the invention;

3 a flow chart of an optical measuring method according to the invention;

4 an image of an object to be measured according to a first optical path;

5 an image of the object to be measured according to a second optical path;

6 the image of the second optical path with increased brightness; and

7 a difference image of the two images of the two optical paths.

1 shows a schematic side view of an optical according to the invention measuring Systems 1 in a processing method with process light 20 , It is a tool head 2 in the form of a laser cutting head 2 present, which is in a direction of movement A on the surface facing it 30 a workpiece to be machined 3 emotional.

The workpiece 3 represents an example of an object 3 to which the present invention can be applied. The laser cutting head 2 can as a tool 20 a process laser beam 20 use, which also as process light 20 can be designated. The process laser beam 20 can the workpiece 3 from the surface facing it 30 cut to perform the machining process of the laser cutting.

In the direction of movement A on the trajectory in front of the laser cutting head 2 is an optical measuring system according to the invention 1 arranged so that this is a constant distance to the process laser beam 30 and with the laser cutting head 2 with and on whose trajectory can move before this. The optical measuring system 1 serves to detect the area in front of the process laser beam 30 to perform a distance measurement here.

For this purpose, the optical measuring system 1 a signal unit 10 in the form of a light source 10 which in this embodiment is a laser source 10 is. The laser source 10 sends a signal light beam 10a in the form of a signal laser beam 10a to the surface facing it to be measured 30 of the workpiece 3 out. The emitted signal laser beam 10a meets there on the trajectory and in the direction of movement A in front of the process laser beam 20 on the surface to be measured 30 of the workpiece 3 and is called a reflected signal laser beam 10b thrown back.

The optical measuring system 1 further comprises an optical detection unit 11 on, which with their optical detection range 11a on the surface to be measured 30 of the workpiece 3 is aligned where the reflected signal laser beam 10b is thrown back. In this area of the surface to be measured 30 of the workpiece 3 detects the optical detection unit 11 an object area 11b , which the reflected signal laser beam 10b and its surroundings on the surface to be measured 30 of the workpiece 3 includes. Under the object area 11b is also understood its optical image. Here is this object area 11b in such a way opposite the process laser beam 20 aligned and arranged that the area in the direction of movement A on the trajectory in front of the process laser beam 20 can be detected sufficiently to detect obstacles that the process laser beam 20 disturb and / or with which the laser cutting head 2 could collide.

To the optical measuring system 1 further includes a data processing unit 16 in the form of a computer unit 16 , which at least with the optical detection unit 11 signal transmitting connected to information and in particular image data from the optical detection unit 11 to obtain. In this embodiment, the computer unit 16 further with the laser source 10 as well as with the laser cutting head 2 or its drives and axes (not shown) signal transmitting connected to receive information from these pages or to be able to transfer this information and in particular control instructions.

It is known the image data of the reflected signal laser beam 10b and the object area 11b z. B. for a distance determination using laser triangulation to obstacles on the trajectory before the process laser beam 20 to recognize. Here, the scattered light of the process laser beam 20 however, as well as sparks that can be generated by laser cutting. These unwanted light effects can be used as stray light 31 be designated. Nevertheless, z. As the laser triangulation for measurement such. B. Distance determination in machining processes with stray light 31 (see. 4 to 7 ) can be used according to the invention as follows:

2 shows a schematic side view of the optical detection unit 11 of the optical measuring system according to the invention 1 , The optical detection unit 11 has a first optical sensor 12 in the form of a first camera 12 and a second optical sensor 13 in the form of a second camera 13 on. Both cameras 12 . 13 basically capture both the reflected signal laser beam 10b as well as the object area 11b or its optical image, which together with the reflected signal laser beam 10b from the workpiece surface 30 to be thrown back. In this case, the reflected signal laser beam 10b and the object area 11b from the first camera 12 on a first optical path 12a and from the second camera 13 on a second optical path 13a detected. The two optical paths 12a . 13a are basically identical.

In the manner described above, the reflected signal laser beam would 10b and the object area 11b from the two cameras 12 . 13 identical and therefore recorded twice. This could eliminate the existing problems of using an optical measuring system such as laser triangulation in stray light processing methods 31 can not be resolved. Therefore, the optical detection unit 11 of the optical measuring system according to the invention 1 in the second optical path 13a ie in front of the second camera 13 , an optical filter 15 in the form of a band-stop filter 15 on.

This bandstop filter 15 However, not as previously known as bandpass filter is designed to the Störlicht 31 of the object area 11b to block and only the reflected signal laser beam 10b to let happen. According to the invention, the procedure is exactly the reverse, by the band-stop filter 15 the reflected signal laser beam 10b blocked and the image of the object area 11b including stray light 31 is passed through. This is done by the second camera 13 captures an image representing the object area 11b with stray light 31 but without the reflected signal laser beam 10b shows. In the first optical path 12a is not such a filter 15 present, so through the first camera 12 the object area 11b with stray light 31 and the reflected signal laser beam 10b is detected.

These two images can now be used by the computer unit 16 which subtract these two images from each other and can thus produce a difference image, which only the reflected signal laser beam 10b having. In this way, according to the invention, the stray light 31 avoided and the reflected signal laser beam 10b be recorded. If the differential image is used for distance detection by means of laser triangulation, the laser triangulation method can be used despite the interfering influences of the process light or the laser cutting machining sparks, in order to carry out an obstacle detection as part of process monitoring.

The optical detection unit 11 also has a beam splitter 14 on which the two optical paths 12a . 13a from the workpiece surface 30 receives and divides them such that the first optical path 12a straight through the beam splitter 14 through to the first camera 12 guided and the second optical path 13a perpendicular from the beam splitter 14 to the band stop filter 15 is distracted. This allows two to the beam splitter 14 identical optical paths 12a . 13a are generated, which represent as possible an identical image of the same scene, which is advantageous for the subsequent difference formation. At the same time, a separation of the two optical paths 12a . 13a be enabled so that only on the second optical path 13a an optical filtering of the reflected signal laser beam 10b can be applied.

3 shows a flow chart of an optical measuring method according to the invention, which is the optical measuring system according to the invention described above 1 can use. The optical measuring method according to the invention proceeds as follows: In a first step 100 becomes the signal laser beam 10a on the workpiece surface 30 as object surface to be measured 30 emitted so that the emitted signal laser beam 10a in the direction of movement A on the trajectory in front of the process laser beam 20 where it hits where the area in front of the process laser beam 20 measured or checked for obstacles. This area represents the object area 11b represents.

In a second step 200 becomes the emitted signal laser beam 10a as a reflected signal laser beam 10b together with the surrounding object area 11b from the workpiece surface 30 sent back, simultaneously and identically on the first optical path 12a and on the second optical path 13a , These optical paths 12a . 13a be from the optical detection unit 11 detected.

In a third step 300 become the reflected signal light beam 10b together with the surrounding object area 11b by means of the beam splitter 14 the optical detection unit 11 in the first optical path 12a and in the second optical path 13a divided.

In a fourth step 400 becomes the reflected signal light beam 10b by means of the band-stop filter 15 the optical detection unit 11 from the second optical path 13a filtered out.

In a fifth step 500 become the first optical path 12a , which is the optical image of the object area 11b including stray light 31 and the reflected signal laser beam 10b as the first image data by the first camera 12 and the second optical path 13a which due to the band rejection filter 15 only the optical image of the object area 11b including stray light 31 however, without the reflected signal laser beam 10b as the second image data through the second camera 13 detected.

In a sixth step 600 becomes the brightness of the second image data of the second optical path 13a customized. This allows a reduced intensity of the second image by the filtering of the fourth step 400 be compensated again.

In a seventh step 700 is generated from the first image data and from the second image data, a difference image which essentially only the reflected signal laser beam 10b and from which the stray light has been filtered out.

4 shows an image of an object to be measured 30 according to the first optical path 12a , This picture represents an object area 11b which exemplifies several lines 10b , which reflected signal laser beams 10b represent, as well as a stray light 31 having. 5 shows the same picture of the object to be measured 30 according to the second optical path 13a from which the reflected signal laser beams 10b already been filtered out, so that only the object area 11b with stray light 31 is shown. 6 shows the image of the second optical path 13a of the 5 with adjusted brightness.

7 shows the difference image of the two images of the two optical paths 12a . 13a , ie the difference image of 4 and 6 , The difference image has the reflected signal laser beam 10b but not the optical image of the object area 11b including stray light 31 , In the 7 is to recognize that by the inventive method, the stray light 31 very dark and comparable to the other areas of the image of the object area 11b is shown, so that the lines of the reflected signal laser beams 11b clearly from the stray light 31 as well as the object area 11b take off. Based on this difference image of 7 Now a laser triangulation can be applied much more successfully than based on the image of the 4 indicating the lines of the reflected signal laser beams 11b and the stray light 31 having.

LIST OF REFERENCE NUMBERS

A

Direction of movement of the tool head 2

1

optical measuring system

10

Signal unit, light source, laser source

10a

to the object surface 30 emitted signal light beam or emitted signal laser beam

10b

from object surface 30 reflected signal light beam or reflected signal laser beam

11

optical detection unit

11a

Optical detection area of the optical detection unit 11

11b

Object area of the optical detection unit 11 on object surface 30

12

first optical sensor or first camera of the optical detection unit 11

12a

optical path of the first optical sensor 12 , first optical path of the reflected signal light beam 10b

13

second optical sensor or second camera of the optical detection unit 11

13a

optical path of the second optical sensor 13 , second optical path of the reflected signal light beam 10b

14

Beam splitter of the optical detection unit 11 , Beam splitter of the first optical path 12a and the second optical path 13a

15

optical filter or band rejection filter of the second optical sensor 13 or the second optical path 13a

16

Data processing unit, computer unit

2

Tool head, laser cutting head

20

Tool, process laser beam, process light

3

Object, workpiece

30

the tool head 2 or the optical measuring system 1 facing object surface to be measured or workpiece surface to be monitored

31

Distortion light of the tool 20 on object surface 30

100

first step of emitting a signal light beam 10a

200

second step of returning a reflected signal light beam 10b

300

third step of dividing the reflected signal light beam 10b

400

Fourth step of filtering out the reflected signal light beam 10b

500

fifth step of simultaneously detecting both optical paths 12a . 13a

600

sixth step of adjusting the brightness of the second optical path 13a

700

seventh step of generating a difference image

Claims (9)

Optical measuring system ( 1 ), with a signal unit ( 10 ), which is formed, a signal light beam ( 10a ) on an object surface to be measured ( 30 ) and with an optical detection unit ( 11 ), which is formed from the surface of the object ( 30 ) reflected signal light beam ( 10b ) together with a surrounding object area ( 11b ), wherein the optical detection unit ( 11 ) a first optical sensor ( 12 ), which is formed, the reflected signal light beam ( 10b ) together with the surrounding object area ( 11b ) on a first optical path ( 12a ), wherein the optical detection unit ( 11 ) further comprises a second optical sensor ( 13 ), which is formed, the reflected signal light beam ( 10b ) together with the surrounding object area ( 11b ) on a second optical path ( 13a ), and wherein the optical detection unit ( 11 ) an optical filter ( 15 ), which in the second optical path ( 13a ) between the object surface to be measured ( 30 ) and the second optical sensor ( 13 ) is arranged and formed, the reflected signal light beam ( 10b ) from the second optical path ( 13a ) and the reflected signal light beam ( 10b ) surrounding object area ( 11b ), characterized by a data processing unit ( 16 ) which is formed, first image data of the first optical path ( 12a ) and second image data of the second optical path ( 13a ) to obtain, the data processing unit ( 16 ) is further configured to generate a difference image from the first image data and from the second image data. Optical measuring system ( 1 ) according to claim 1, further comprising a beam splitter ( 14 ), which is formed, the reflected signal light beam ( 10b ) together with the surrounding object area ( 11a ) in the first optical path ( 12a ) and the second optical path ( 13a ), the optical filter ( 15 ) in the second optical path ( 13a ) between the beam splitter ( 14 ) and the second optical sensor ( 13 ) is arranged. Optical measuring system ( 1 ) according to claim 1 or 2, wherein the optical filter ( 15 ) a band stop filter ( 15 ), which is formed, the wavelength of the reflected signal light beam ( 10b ) from the second optical path ( 13a ) filter out. Optical measuring system ( 1 ) according to one of the preceding claims, wherein the first optical sensor ( 12 ) and / or the second optical sensor ( 13 ) a camera ( 12 . 13 ), in particular a high-speed camera ( 12 . 13 ), is / are. Optical measuring system ( 1 ) according to one of the preceding claims, wherein the data processing unit ( 16 ) is further configured to perform a triangulation based on the difference image. Optical measuring system ( 1 ) according to one of the preceding claims, wherein the second optical sensor ( 13 ) and / or the data processing unit ( 16 ) is formed, in the image data of the second optical path ( 13a ) perform a brightness adjustment. Optical measuring method, with the steps: sending ( 100 ) of a signal light beam ( 10a ) on an object surface to be measured ( 30 ), Returns ( 200 ) one of the object surface ( 30 ) reflected signal light beam ( 10b ) together with a surrounding object area ( 11b ) on a first optical path ( 12a ) and on a second optical path ( 13a ), Filtering out ( 400 ) of the reflected signal light beam ( 10b ) from the second optical path ( 13a ), simultaneous capture ( 500 ) of the first optical path ( 12a ) as the first image data and the second optical path ( 13a ) as second image data, and generation ( 700 ) of a difference image from the first image data and from the second image data. An optical measuring method according to claim 7, comprising the further step between the step of returning ( 200 ) and the step of filtering out ( 400 ): Share ( 300 ) of the reflected signal light beam ( 10b ) together with the surrounding object area ( 11b ) in the first optical path ( 12a ) and the second optical path ( 13a ). Optical measuring method according to claim 7 or 8, comprising the further step after the step of simultaneous detection ( 500 ): To adjust ( 600 ) the brightness of the second image data of the second optical path ( 13a ).

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