DE102017129221A1 - Method and device for determining geometric features on workpieces - Google Patents

Abstract

The invention relates to a method for determining the position of at least one region on, in particular, at least one cutting edge, wherein the determination is effected by means of an image processing sensor and images are recorded in a plurality of rotational positions of the tool and the regions in the image are determined and examined by evaluating the recorded images. in which the cutting edge is in focus. The rotational movement and the axial movement of the tool are controlled in such a way that the cutting edge is followed, wherein the movement speed in the axial direction is controlled so that the respective sharply imaged region of the cutting edge always remains within the range detected by the image processing sensor as the rotational position changes ,

Description

Subject of an independent invention is a method for measuring the position of features, in particular sheaths, which are preferably arranged twisted on the circumference of a tool.

For measuring cutting edges or other features present on the circumference, in particular twisted, on a tool such as drills, milling cutters, stepped drills, etc., known methods relate to the detection of the cutting edge in a rotational position in which it is detected sharply by an image processing sensor. The focal plane of the image processing sensor is set in the axis of rotation of the tool. A corresponding method is for example in the DE 10 2011 056 819.0 the applicant and is referred to as Hüllkonturscanning. The detection of whether the cutting edge is sharp in the image can be done in two different ways.

After the first possibility, the maximum point, ie the maximum distance of the image of the cutting edge in the image to the tool axis of rotation or tool axis of symmetry, is determined. Here, the images from several rotational positions are examined and the maximum points superimposed. This results in the so-called envelope contour, which corresponds to the active contour of the tool. The maximum points result from sharp imaging of the respective area of the cutting edge. Alternatively, the images, ie the gray values of the images, can be completely overlaid. As a result, the same result for the envelope contour is achieved since image areas have the blurred images of the cutting edge, have smaller distance to the tool axis of symmetry, and are thus covered by corresponding areas of the images in which the respective cutting area sharp, ie further out, imaged becomes. If the position of the cutting edge in the room is to be determined, the maximum points must be determined as a function of the rotational and axial position.

The second possibility provides that the contrast is evaluated in order to assess the focus of the cutting edge. In the areas where this is maximum, there is a sharp edge or a sharply imaged area of a cutting edge. There are basically several options for taking pictures. After the first possibility, a rotational movement is first performed by at least 360 ° in order to capture the tool in a first axial section on its entire circumference. In the case of twisted features such as cutting, the respective sharply imaged region of the respective cutting edge migrates in the axial direction through the image. When there are several cutting edges, the cutting edges move in succession or, depending on the distance, together, but offset axially, through the image. The disadvantage here is that the entire tool must be studied consuming on its circumference, so even at places where there is no cutting edge. A second possibility provides that the image acquisition initially takes place only in the axial direction and then further axial scans are carried out in further rotational positions. However, this can not be guaranteed that the cutting edges are completely detected in focus areas. After a third possibility is provided to combine the rotational and axial movement and to capture the cutting edge. For this purpose, advance information about the position of the cutting edge in high accuracy is required so that the cutting edge remains sharp in the image.

The disadvantage here, however, is that the slope of each cutting edge to be measured must be known very well and the corresponding positioning movements along a trajectory then fixed at a once fixed speed, such as the EP 2 668 464 describes. As a result, it is also not possible to follow unknown cutting or cutting with unknown slope dynamically, so measure time-saving.

A first object of the present invention is therefore to avoid the problems of the prior art and in particular to enable a rapid measurement of tools with twisted features such as cutting, in particular provided to track the blade dynamically and unknown cutting to measure and track.

To solve the invention provides that rotational and axial movement are controlled when following the cutting edge so that each detected in the focal plane of an image processing sensor area of the cutting always within the recorded image, preferably in a central region of the image remains. This makes it possible to adjust the axial velocity at, for example, a constant rotational speed corresponding to the axial displacement of the respectively sharply detected region of the cutting edge resulting from the rotational movement. This allows in particular very high measuring speeds. The method can also be used in particular for unknown cutting, since they are tracked dynamically.

If the position of the cutting edge is at least roughly known, the invention provides, according to an independent idea, that the cutting edge is detected and measured by tracing a predefined path calculated from the known cutting position in an unregulated scanning. The default track will be calculated, for example, from preliminary information such as CAD data or cutting edge geometry or cutting parameters on the position of the cutting edge or features to be measured.

In order to compensate for possible deviations of the actual cutting edge position to the default path, so still completely capture the cutting edge, the invention provides for a separate idea two solutions. After the first solution, each time the preset path is traversed, it is determined where in the image area an area of the cutting edge is in focus (sharpening area). If this area is removed too far from the center of the image (central area of definable size), the default path or web is adjusted accordingly to automatically track the cutting edge. The second solution provides that the departure of the Vorgabebahn an oscillating rotational movement of the tool is superimposed. Amplitude and frequency of this oscillation is preferably freely adjustable and can be adapted to the default path, so the basic course of the cutting edge, and the expected deviations of the real cutting edge to the default path. This ensures that areas of the cutting edge that deviate from the standard path are also detected. An active detection and control of the position of the focus areas in the respective image can be omitted, whereby the process is very fast, so high rotational and axial movements can be realized.

The invention provides for the solution, a method for determining the position of one or more areas on one or more cutting or teeth or chamfer or other distributed on the circumference of a tool features, preferably distributed on the outer circumference features on a tool, wherein the cutting or features Depending on the axial position along the axis of the tool in partially different rotational positions, the tool thus has in particular twisted cutting edges or features, wherein the determination by image processing sensor, in particular in a coordinate measuring machine integrated image processing sensor, preferably illumination in transmitted light and / or bright field incident light and / or darkfield incident light, where images are recorded in several rotational positions of the tool about its tool axis and in a plurality of relative positions between the tool and the image processing sensor in the direction of the tool axis, and by evaluating the taken pictures are the areas in the image or in the resulting images, which are generated by overlaying and / or Aneinanderetzen the individual images are determined and examined, in which the cutting edge or features are sharply displayed, in particular by evaluating the vertical distance to the position of the tool axis and / or by evaluating the image contrast, which is characterized in that the rotational movement and the axial movement, ie in the direction of the tool axis, are controlled in such a way that the cutting edge or the feature is followed in its preferably twisted or helical shape, wherein the movement speed in the axial direction is controlled such that the respective sharply imaged region of the cutting edge or feature remains in the region covered by the image processing sensor when the change, preferably continuous change, of the rotational position always remains, preferably in the center It remains in an allowable range defined by the center of the image.

In particular, the invention is characterized in that a first region of the cutting edge or feature in a first rotational position and a first axial position is set sharply and this position is selected as a starting point for the continuous movement.

Preferably, it is provided that, starting from the starting point, a continuous rotational movement, preferably continuous rotational movement with constant rotational speed, in a predetermined direction of rotation, which preferably corresponds to the twisting direction of the cutting edge or the feature of the tool is determined, and the axial movement and preferably a second linear motion in the direction perpendicular to the tool axis and perpendicular to the imaging direction as optical axis, the image processing sensor is controlled.

In particular, the invention is distinguished by the fact that advance information such as CAD data or cutting edge geometry or cutting parameters about the position of the cutting edge or features to be measured are used as the default path for implementing the axial and rotary motion, and rotational and axial movement initially along the predefined path takes place, wherein the web is adjusted only when the focus area leaves a previously defined central area within each recorded image.

A separate idea is to dynamically correct deviations from the focusing of the cutting edge, by using an optical distance sensor, such as laser distance sensor, which preferably at least is partially integrated into the beam path of the image processing sensor, the distance between the tool, in particular tool edge, and readjust the image processing sensor, so that a continuous focus is ensured.

Preferably, the invention therefore provides that, at the same time as the image recording, a preferably in the beam path of the image processing sensor integrated punk optical distance sensor, the focus of the image processing sensor, so setting the distance in the direction of the optical axis of the image processing sensor between the tool and image processing sensor is set, and preferably during the pursuit of the railway is refocused.

In order to produce sharp images, it is also proposed to perform a superimposition of short-exposed individual images. These must be superimposed to a high proportion, preferably at least 50%. The short exposure enables high measuring speeds with low motion blur. The recording positions of the individual images are taken into account in the superposition, so that corresponding image areas are superimposed in their gray values.

It should be emphasized, furthermore, that the image recording takes place during the combined rotational and axial movement and the individual images recorded overlap at least partially, preferably more than 50%, the individual images taking into account the recording position of the image processing sensor with respect to the position and rotational position of the tool, are aligned and superimposed on each other, wherein the superposition preferably takes place by at least adding the gray values and preferably normalizing the gray values corresponding to the number of superimposed images per image area.

In development it is also provided to correct the wobble of the tool. This is done on the basis of the previously determined position of the axis of rotation during the rotation of the tool with respect to the tool axis of symmetry. On the basis of this relationship, which is known per rotational position, either the recorded images are correspondingly displaced before the evaluation or superposition and / or the tool and the image processing sensor are positioned relative to one another.

Preferably, the invention also provides that the recorded images are superimposed to form a hull contour and / or a contour of the cutting edge in space or as a developed representation is determined from the recorded images. In the superimposition of the envelope contour, a particular embodiment of the invention provides that only the image areas are used for superposition, which exceed a specified threshold value of the image sharpness. Preferably, the normalization of the image areas then takes place depending on how many images were used for the respective area in the superimposed overall image. An area can also be the size of a single pixel. The subject of an independent invention is an apparatus and a method for the optical determination of geometric features, in particular measuring points on a workpiece by means of an optical sensor having a zoom lens and an optical distance sensor.

For the optical measurement of geometric features, in particular measuring points on workpieces, image processing methods, focus variation methods, both executable with, for example, the same image processing sensor, and various methods using optical distance sensors are known. In particular interferometric, confocal and chromatic, preferably chromatic-confocal methods, but also triangulation methods, for example Foucault's sensors, are known as optical distance sensors.

The optics for an image processing sensor is advantageously designed as zoom optics in order to be able to use different magnifications (zoom levels), wherein preferably additionally the working distance can be set independently of the magnification, like the EP1071922 the applicant describes. For this purpose, several lenses of a zoom lens system are displaceable in the imaging direction. Particularly preferred image processing sensor and optical distance sensor are combined in an optical sensor head, so use at least one common object-side or workpiece side lens presystem, as for example in the EP1299691 the applicant is described. In this case, the measuring beam of the optical distance sensor must be reflected in the optics of the image processing sensor. The beam splitters required for this, however, take up space that is no longer available for the displacement of the lenses of the zoom lens system. In particular, it is no longer possible to move the object-side lens of the zoom lens system very close to the image-side lens of the lens presystem. For example, the reflection of the measuring beam of a chromatic distance sensor can be provided at this point.

A further object of the present invention is therefore to provide an optical sensor head which has the largest possible displacement range for the displaceable lenses of a zoom lens system and nevertheless comprises an optical distance sensor. The object of the invention is also to design a method for operating such an optical sensor head for the measurement with an image processing sensor and the optical distance sensor.

To solve the invention provides that a lens of the zoom lens system has a central opening for supplying the measuring beam of an optical distance sensor leading optical fiber.

The invention provides for the solution an optical sensor head which has an optical system which comprises at least one object-side lens system and a zoom lens system with one or more imaging lenses displaceable zoom lenses, wherein the optical sensor head further comprises an optical distance sensor, the one measuring beam of the optical distance sensor having feeding optical fiber, and is characterized in that a first zoom lens has a central opening, which is supplied to the optical fiber and that the object-side end of the fiber, preferably together with the first zoom lens, is displaceable in the imaging direction.

In particular, the invention is characterized in that the optical fiber leaves the first zoom lens image side, and preferably in the space between the first zoom lens and another zoom lens or other lens of the optics leaves the optical path of the optics, and the measuring beam at the object end of the optical fiber leaves in the direction of the lens presystem. The fiber is inserted into the zoom lens from behind and the fiber end points forward towards the workpiece. The fiber end can project something out of the zoom lens.

Preferably, it is provided that the object-side end of the optical fiber is fixed in the opening of the first zoom lens. As a result, the displacement of the fiber can be effected by the displacement of the zoom lens and an additional positioning unit can be dispensed with.

In particular, the invention is characterized in that the optical distance sensor is a chromatic distance sensor, preferably a chromatically confocal distance sensor, and at least one lens of the lens presystem has a chromatic aberration.

A disadvantage of known chromatic distance sensors is also that the position of the image-side focal plane in chromatic optics, which have a chromatic aberration so a targeted color error, can be easily wavelength dependent. This can occur in particular if, due to the overlapping chromatic aberrations of the lenses (doublets or triplets), there is no monotone wavelength-dependent course of the object-side focal length. As a result, the measuring beam reflected from the workpiece to be measured is not ideally coupled back into the measuring fiber of the chromatic sensor from which the measuring beam was emitted. Signal strength is lost as a result. In addition, the signal strengths of the wavelength components change with each other, which leads to measurement errors.

Another object of the present invention is therefore to design an optical sensor head so that it can be measured particularly accurately with an integrated chromatic distance sensor as an optical distance sensor.

To solve the invention therefore also provides that a lens of a Vorlinsensystems, which is the object side of the reflection of the measuring beam of the chromatic sensor is arranged in the optics, displaceable in the imaging direction or as adjustable in their focal length lens such as liquid lens to the focusing (refocusing ) of the workpiece most strongly reflected portion of the measuring beam (6a) in the object-side fiber end (7b) to realize.

In this case, it is also provided that it is taken into account that a change in focus on the image side likewise leads to an object-side changed focal length, that is to say to a changed working distance. The characteristic of the chromatic sensor is thus shifted in the distance direction. During the measurement, the refocussing shifts the wavelength which is most strongly reflected by the workpiece to the extent of refocussing, so that the wavelength to be focussed on the image side also shifts and the optimal state must be found iteratively. The effect can be determined by prior measurement and taken into account during the measurement.

As the focal length adjustable lens, for example, fluid lens (liquid lens) or so-called TAG lenses (lenses with tunable acoustic gradient refractive index) understood, which are also referred to as LC lenses (lenses with variable focal length) or VFL lenses and whose focal length is electronically controllable.

Thus, the invention also provides for an optical sensor head which has an optical system and an optical distance sensor designed as a chromatic distance sensor, which is preferably a chromatically confocal distance sensor whose measuring beam is reflected into the optical system from a fiber end, preferably by means of a beam splitter , and wherein on the object side of the reflection, a lens of a lens aberration system with a chromatic aberration is arranged, and preferably on the image side of the reflection a zoom lens system is arranged, and characterized in that the lens system comprises a lens which displaceable in the imaging direction or as in their Focal length adjustable lens like Liquid lens and for focusing the most highly reflected from the workpiece portion of the measuring beam is formed in the object-side fiber end.

The following extensions and methods mentioned later are equally applicable to the sensor head mentioned immediately above, but also to the aforementioned sensor head in which a lens of the zoom lens system has a central opening for supplying the optical fiber guiding the measurement beam of an optical distance sensor.

Preferably, the invention provides that the optical sensor head comprises an image processing sensor, comprising at least the optics and an image acquisition unit such as CCD or CMOS camera, wherein beam paths of the image processing sensor and the optical distance sensor undergo a common lens presystem. Between zoom lens system and camera, for example, further imaging lenses are provided.

It should also be emphasized that the lenses of the zoom lens system are designed to be adjusted in the imaging direction in such a way that the object-side working distance and the image scale of the optics for the image processing sensor can be set independently of one another.

In particular, the invention is characterized in that at least one of the zoom lenses of the zoom lens system and / or at least one of the lenses of the lens presystem is designed as a lens adjustable in its focal length, such as a liquid lens. This makes it possible to achieve a particularly rapid adaptation, which is required, for example, when using the optical distance sensor in scanning operation. If a lens of the zoom lens system is formed as a liquid lens, thereby the rapid switching between different magnifications and working distances is possible. If a lens is designed to be adjustable in its focal length, which is arranged on the object side relative to the first zoom lens to which the optical fiber is fed or which is arranged on the object side with respect to the reflection, then the focusing of the lens can be achieved by driving this lens From the workpiece returning measuring beam of the optical distance sensor in the optical fiber realize very quickly. This lens may be a lens of the lens presystem or the zoom lens system. Under certain circumstances, this focusing may be necessary, for example, when used in scanning mode, because, as already mentioned above, the image-side focal plane in the case of chromatic optics can be wavelength-dependent.

Preferably, it is provided that the optics have reflection for a bright field illumination and / or brand projection and / or further optical distance sensor such as distance sensor according to the Foucault principle, and / or filters and / or diaphragms.

In a particularly preferred embodiment, the optical sensor head is integrated in a coordinate measuring machine, which in particular has measuring axes.

The object of the invention is also to design a method for operating such an optical sensor head for the measurement with an image processing sensor and the optical distance sensor.

To solve the invention, the invention also provides a method for operating such an optical sensor head for the measurement with an image processing sensor and the optical distance sensor by the object-side end of the fiber, the one or more zoom lenses are moved in the imaging direction in positions, optionally the measurement with the allow optical distance sensor or the image processing sensor.

According to the invention, it is also provided to observe the workpiece surface with the image processing sensor during the measurement with the optical distance sensor or the preparation of the measurement with the optical distance sensor, in particular the surface area of the workpiece detected by the distance sensor, the point of impact of the measuring beam of the optical distance sensor preferably being on the Workpiece surface is visible in the images recorded by the image processing sensor, for example, to adjust the point to be measured on the workpiece surface.

The invention provides for the solution a method for the determination of geometric features on a workpiece, in particular determination of measuring points using the aforementioned device, which is characterized in that either either object-side end of the fiber, preferably together with the first zoom lens, in the imaging direction is shifted to a first position, in which the object-side end of the fiber is arranged in the image-side focal point of the lens presystem to record measuring points with the optical distance sensor, or the one or more zoom lenses are moved in the imaging direction in positions to working distance and / or magnification for adjust the image processing sensor and detected with the image processing sensor contours of the workpiece and measuring points are determined or with the image processing sensor by means of focus variation method images of the workpiece at different distances between Werkstü ck and Object focal point of the optics detected and determined by contrast or brightness evaluation measurement points.

It should be noted that it should be noted that the position of the image-side focal plane in chromatic optics, which have a chromatic aberration so a targeted color error, can be slightly wavelength dependent. In this case, there are several possibilities for the positioning of the object-side fiber end in the image-side focal point of the lens presystem. According to a first procedure, it is provided to position the fiber end in the region of the focal plane of a central wavelength and to leave it during the measurement. As a result, a particularly accurate measurement is only possible if the respectively detected area of the workpiece surface is located in the object-side focal plane. To achieve this, a corresponding adjustment is made for the measurement by adjusting or moving the distance between the optical sensor head and the workpiece, for example by means of the measuring axes of a coordinate measuring machine in which the optical sensor head is integrated or by adjusting the focal length of the optical system becomes. An accurate measurement is also possible by artificially reducing the measuring range of the optical distance sensor in the imaging direction. A second approach provides that the fiber end of the image-side focal plane is tracked according to the respective strongest wavelength, or the other way around, the image-side focal plane is readjusted to the position of the fiber end. For this purpose, either the fiber end receiving lens can be moved (or the fiber end itself, unless this is excluded from a lens) or the position of the focal plane itself is adapted to the fixed position of the fiber end by adjusting at least the focal length of the lenses of the lens system This is preferably done by using a variable focal length lens such as liquid lens. This procedure allows in particular the operation of the optical distance sensor with continuous data acquisition and displacement of the workpiece relative to the optical sensor head transversely to the imaging direction (scanning operation).

In particular, the invention is characterized in that during the measurement with the formed as a chromatic distance sensor optical distance sensor, the measuring beam reflected from the workpiece receiving fiber end in the imaging direction of the optics of the position of the wavelength-dependent image-side focal point of the measuring beam on the workpiece imaging lens precursor or the wavelength-dependent Image-side focal point of the lens leading system in the imaging direction of the position of the fiber end for the wavelength (color) of each of the measurement object or workpiece most reflected portion of the measuring beam is tracked, wherein the optical distance sensor is preferably operated in the scanning mode.

The subject matter of an independent invention is a method for determining contours, in particular contour points or measuring points, on a measuring object, in particular a workpiece, by means of image processing, in particular 2D image processing.

The US 4,710,876 describes the method known as the marching cube, in which three-dimensional voxel data, originating from a computed tomography radiographing the subject, are used to determine subvoxel-precise contour points. The algorithm searches the entire voxel volume with a single, easy-to-program and efficient algorithm using a single threshold. The disadvantage, however, is that local aberrations lead to deviations.

Another known method for determining the position of contour points with high resolution are for three-dimensional voxel data, originating from a computed tomography radiographing the object in the EP 1 861 822 A1 described. Here, a segmentation in the object and background area is first performed by means of a threshold value specified by the operator, for example by means of the "marching cube" method, and then the position of the contour points is calculated subvoxel accurately by interpolation along several search beams through the transition areas between object and background to consider local aberrations. The evaluation of a multiplicity of search beams is laborious and leads to inhomogeneous results, in particular an irregular contour point spacing or pattern and a lack of neighborhood assignments between the contour points. As a result, it is no longer possible, for example, to create closed, networked surface representations.

The DE102013109632.8 The applicant describes a three-dimensional voxel volume, originating from a computed tomography radiographing the object, in which the two aforementioned methods are combined in order to generate globally subvoxel-accurate, simple and fast cross-linked surface displays using the marching cube method and yet local aberrations to be able to determine contour points from three-dimensional voxel data. The content is referred to in full.

The disadvantage, however, is that corresponding algorithms are not available for two-dimensional image data, an application for the classical 2D Image processing is not possible. In particular, local lighting variations can not be compensated.

A further object of the present invention is therefore to measure contour points or measuring points on a workpiece particularly accurately and nevertheless quickly with image processing and thereby to take account of local aberrations. In particular, closed contours (contour curves from contour points) with a unique neighborhood assignment should be generated.

To solve the invention essentially provides the following inventive steps. First of all, a comparable global algorithm or operator (also known as "marching square") for subpixel-accurate determination of contour points on 2D images is proposed for the three-dimensional "marching cube" method. This works with a single, global threshold and searches the gray-scale amplitudes of the pixels of the 2D image to be examined, instead of 3D voxel volume data, so it is limited by one dimension. As a result, it is possible to generate first contour points which, however, do not yet take into account local aberrations or, in the case of image processing, in particular local illumination variations, that is, they may still be inaccurate in their position. In the next step, the gray scale amplitudes of the pixels of the image are adjusted in the local environment of these contour points in accordance with the local conditions, and then second, improved contour points are calculated by means of a renewed application of a global operator such as "Marching Square". The last step enables the generation of a closed contour (contour definition). The local adaptation of the gray value amplitudes takes into account, on the one hand, the locally different aberrations and locally varying illumination conditions and, on the other hand, allows the subsequent application of a global operator with only a single threshold value, whereby a simple calculation is possible. As a result of the reapplication of the global operator, the same surface points are created as would have been the result of local examination of the gray scale amplitudes using search beams. This is not only mathematically easier to implement, but also eliminates the definition of profile lines (search beams), without losing the advantage of local subpixel accurate determination of surface points. In addition, in the inventive idea, the possibility remains of increasing the local resolution of the contour points and thus the number of contour points or density of the edge description defined by the contour points, beyond the amount predefined after the application of the first global operator.

Another inventive step describes a way to increase the spatial resolution of the first contour points, again based on the application of a global operator, by subsequently increasing the resolution of the pixels of the image, in particular by interpolating local intermediate points to reduce the pitch of the pixel center distances. To reduce the amount of data and increase the processing speed, however, a reduction of the resolution is possible. The increased resolution remains limited to the environment of the first contour points in order to save storage and computing time. This limitation is permissible since the area of the object edges is already completely covered by the first contour points and in the further procedure only this selected area of the image pixels must be examined. With the modified resolution, the known steps of applying the global operator to generate the improved contour points and a closed contour, or the local investigation by local operator to generate improved contour points that take into account the local aberrations and illumination variations, can now take place. If all these advantages are to be achieved simultaneously, the image, which is at least partially changed in resolution, is used for the local adaptation of the gray-scale amplitudes of the pixels corresponding to the previous inventive step, thus combining the two inventive steps.

• - Bestimmung jeweils zumindest einer lokalen Referenzgrauwertamplitude aus den Grauwertamplituden der Pixel in der Umgebung der ersten Konturpunkte und vorzugsweise zumindest einer globalen Referenzgrauwertamplitude aus den Grauwertamplituden der Pixel des Bildes,
• - Anpassung der Grauwerte der Pixel, wobei die Grauwerte der Pixel in jeweils der lokalen Umgebung der ersten Konturpunkte unter Verwendung zumindest der lokalen Referenzgrauwertamplituden normiert werden, vorzugsweise so, dass mit einem globalen Operator, wie globaler Schwellwertoperator oder globaler differentieller Operator, die gleichen zweiten Konturpunkte berechenbar sind, wie durch Anwendung der jeweils lokalen Referenzgrauwertamplituden als Schwellwert für einen lokalen Operator, wie lokaler Schwellwertoperator oder lokaler differentieller Operator

• - Anwendung zumindest eines zweiten globalen Operators, vorzugsweise globalen Schwellwertoperators oder globalen differentiellen Operators, auf die angepassten Grauwerte aller oder eines Teils der Pixel des Bildes zur Bestimmung zweiter Konturpunkte
• - Verwendung der ermittelten zweiten Konturpunkte als Konturen bzw. Konturpunkte.

The invention provides for the solution a method for determining contours, in particular contour points, on a measurement object, in particular a workpiece by image processing, in particular 2D image processing, wherein the contours or contour points of higher resolution are obtained from the gray values of the pixels of the respective image (gray value amplitudes) the contour point positions are determined as determined by the pixel center distances of the image and / or taking into account the gray values in the environment of the respective contour point by first determining the positions of first contour points by applying to the gray values of all or part of the pixels of the image at least a first global operator, preferably global threshold operator or global differential operator, is applied and the global threshold value or the global threshold amplitude used is provided, which is characterized in that subsequently to the area of the image i The following steps are applied to the local environments of the first contour points:

• Determining in each case at least one local reference gray-scale amplitude from the gray scale amplitudes of the pixels in the vicinity of the first contour points, and preferably at least a global reference gray value amplitude from the gray scale amplitudes of the pixels of the image,
• Adjusting the gray values of the pixels, the gray values of the pixels in each of the local surroundings of the first contour points being normalized using at least the local reference gray value amplitudes, preferably such that with a global operator, such as global threshold operator or global differential operator, the same second contour points are calculable, such as by applying the respective local reference gray value amplitudes as a threshold for a local operator, such as local threshold operator or local differential operator

• Apply at least one second global operator, preferably global threshold operator or global differential operator, to the adjusted gray values of all or part of the pixels of the image for determining second contour points
• Use of the determined second contour points as contours or contour points.

In particular, the invention is characterized in that the local reference gray value amplitudes are determined by applying at least one local operator, the at least the minimum and / or maximum gray scale amplitude and / or the course of the gray scale amplitudes and / or a gray value amplitude calculated therefrom, from the gray scale amplitudes in the Determined environment of the respective first contour point, preferably after applying an image correction and / or filtering, preferably low-pass filtering, the gray scale amplitudes.

Preferably, it is provided that the size of the local operator is set such that at least the complete edge transition in the region of the respective first contour point, locally defined by the distance of the brightest to the darkest gray scale amplitude, is detected.

• - die gemittelte Grauwertamplitude oder
• - die Hälfte der Summer der maximalen und minimalen Grauwertamplitude oder
• - die Hälfte der Differenz aus maximaler und minimaler Grauwertamplitude
• - und vorzugsweise zusätzliche Berücksichtigung eines Skalierungsfaktors und/oder eines konstanten Offsets, vorzugsweise der minimalen Grauwertamplitude

oder

• - die Grauwertamplitude am Ort des größten Grauwertamplitudengradienten oder größter zweiter oder dritter Ableitung oder
• - die Grauwertamplitude am steilsten Bereich, insbesondere Wendepunkt oder Maximum des lokalen Grauwertgradienten, oder am Bereich der größten zweiten oder dritten Ableitung, entlang einer durch die lokale Umgebung des jeweiligen Konturpunktes verlaufenden Profillinie oder
• - die Grauwertamplitude am Ort der größten Korrelation, vorzugsweise größten Kreuzkorrelation, mit einer angenommenen Kantenfunktion und/oder
• - die Grauwertamplitude an der durch ein CAD-Modell definierten Kante bzw. Kantenpunkt

im jeweils vom lokalen Operator überdeckten lokalen Bereich des Bildes.In particular, the invention is characterized in that a local reference gray value amplitude is determined by:

• - the averaged gray value amplitude or
• - half of the maximum and minimum gray scale amplitude or
• - Half the difference between maximum and minimum gray value amplitude
• - and preferably additional consideration of a scaling factor and / or a constant offset, preferably the minimum gray scale amplitude

or

• the gray value amplitude at the location of the largest gray value amplitude gradient or the largest second or third derivative or
• - The gray scale amplitude at the steepest area, in particular turning point or maximum of the local gray scale gradient, or at the area of the largest second or third derivative, along a running through the local environment of the respective contour point profile line or
• the gray value amplitude at the location of the greatest correlation, preferably the largest cross correlation, with an assumed edge function and / or
• the gray value amplitude at the edge or edge point defined by a CAD model

in each case covered by the local operator local area of the image.

Preferably, the invention provides that in each case a local characteristic value is calculated, wherein one of the local reference gray value amplitudes or a functional relationship between a plurality of local reference gray value amplitudes is used as the characteristic value.

It should also be emphasized that in order to normalize, the grayscale amplitudes of the pixels in the respective surroundings around the first contour points are increased or decreased in such a way that the same positions for the second contour points are obtained by using the global operator, preferably marching square operator using the global threshold amplitude, as by applying the respective local operator.

The invention is also distinguished by the fact that for normalization from the global and the respective local characteristic value, by quotient formation or subtraction, in each case a scaling factor or offset is calculated, with which the gray-scale amplitudes of the pixels in the respective surroundings around the first contour points are multiplied or the offset is added, wherein preferably the scaling factors or offsets, which were determined for adjacent pixels, averaged or scaled with their distance to the respective pixel, are additionally applied proportionally.

In particular, the invention is characterized in that the method is used in a coordinate measuring machine, in which an image processing sensor is integrated, wherein for receiving the image to be evaluated, the workpiece is illuminated by transmitted light, bright field incident light and / or dark field reflected light, preferably in a flash.

The subject matter of an independent invention is a method for adapting a surface description of a workpiece or tool, preferably a CAD model, particularly preferably in Nurbs format, to a point cloud, as well as a computer program for this purpose.

Nurbs (Non-uniform rational B-splines) are mathematically defined curves or surfaces that are used to model arbitrary shapes. A nurbs can represent any non-branching continuous line. So-called control points are always either directly connected to the curve or surface or act as if they are connected to a rubber band. Surface descriptions such as CAD models are modeled by Nurbs, for example. In general, a description is possible through Bezier surfaces (Bezier surfaces and B-spline surfaces) that describe the same space with a different basis compared to NURBS. NURBS thus represent a subset of the B-spline surfaces).

Known methods for adapting CAD models for tool correction are described in US Pat DE102015121582.9 described in the applicant, whose contents are fully incorporated herein by reference. It describes, inter alia, that the deviations between the desired data of a workpiece, in particular a given surface model such as CAD model in Nurbs format, for example, or also derived therefrom, STL format, which thus represents the desired state of a workpiece to be produced, to a measured point cloud be determined on the workpiece and these deviations are used for the correction of the surface model of the workpiece or for the correction of the target data of the tool as surface model of the tool, which in turn is derived from the surface model of the workpiece will use. If necessary, the deviations must be inverted, ie mirrored to the original setpoint data. If, for example, a workpiece is made too small at a certain point, the tool was obviously too large at the point concerned. If, for example, the so-called inverted workpiece model was used as the basis for the generation of the tool model, the workpiece model at the relevant point was too small and must be enlarged for correction at this point so that a smaller tool is created at this point, for example by regrinding. Too small a finished workpiece thus leads here to an increase in the target data. Too small means that the deviations from the target data point into the interior of the workpiece. Enlarging the setpoint data means that the corrections point away from the inside of the workpiece, ie in opposite, inverted direction, ie they have to be mirrored in the setpoint data. If the tool is corrected directly, this inversion is omitted. If a negative image of the tool (referred to here as an intermediate tool) is created in an intermediate step, for. As an electrode for eroding the tool, previously mentioned considerations invert again. Furthermore, no distinction is made between the correction of the tool setpoint data and the intermediate tool setpoint data, and the setpoint tool setpoint data is spoken for both cases.

Tool correction is the correction of a tool used for the production of a workpiece, such as regrinding of the tool or here only the steps for determining the correction to be performed. For the production of the tool itself, the tool setpoint data, which are derived from the setpoint data of the workpiece to be produced, are used in the first step.

In the following correction loops, the corrected target data of the workpiece are then used to determine corrected tool setpoint data, or corrected tool setpoint data are generated directly from the measured deviations of the workpiece. Thus, the surface model of the workpiece and / or the tool is corrected.

Methods for tool correction are also exemplary in the EP2313867 for generating the points with a computer tomograph.

In the context of the present invention, the determination of the surface points is preferably provided with a coordinate measuring machine with tactile and / or optical and / or tactile-optical and / or computer-tomographic sensors. Multi-sensor coordinate measuring machines with several of these sensors are preferably used.

However, the solutions described do not exist in a single software, ie as a consistently operable and thus completely teachable solution. An automatic CNC process is not possible. In the known methods, the CAD model of the workpiece is first implemented by a separate CAD / CAM programming system such as Tebis Technical Information Systems AG, based in Martinsried near Munich or Delcam in a machine-readable format. An intermediate format may also be a surface description of the workpiece or tool in STL format. In particular, the desired data of the tool are generated from the desired data of the workpiece.

Tebis is a CAD / CAM software solution for z. B. tool, mold or model. The software mainly produces toolpaths for cutting production such as drilling, milling and turning, as well as wire and sink EDM. The toolpaths control multi-axis CNC machines. Further areas of application are work preparation, design, reverse engineering, quality control, CNC machine and bank assembly. The software has interfaces for neutral data formats as well as for file formats from other manufacturers (STEP 203/214, VDA-FS, IGES, DXF, STL, Parasolid, CATIA V4 / V5, Creo, SolidWorks, NX, JT, Nastran, Autoform) ( Source: https://de.wikipedia.org/wiki/Tebis, call on 18.05.2017, 10:45 clock).

In an integrated or further separate step, a G-code for controlling the machine tool such as milling machine or the like is created by means of a post-processor of, for example, Siemens or Fanuc, with which either directly a tool or an intermediate tool used to produce the tool such as electrode for the erosion of a tool is made.

A first sample workpiece (master part) or a series part is then dimensionally examined by means of a measuring device, preferably a coordinate measuring machine, ie measured. For this purpose, a separate software is again used, for example, comes from the manufacturer of the coordinate measuring machine. The comparison of the measurement results, such as point cloud with the original CAD model is usually done with the coordinate measuring machine software. Separate software solutions for this exist as well.

In particular for the adaptation of the original target data based on the deviations between the measurement result (actual data) and the original target data (eg CAD model of the workpiece) determined with the coordinate measuring machine, there are no uniform software solutions. It is therefore also here a separate software such as reverse engineering software required, the interfaces for the measurement results of the coordinate measuring machine and the original target data, as well as corrected target data must have. Thus, at least three different software programs and usually separate hardware are usually required to perform a tool correction. An automatic CNC process is therefore not possible.

Another fundamental problem with tooling correction is that a costly new tool must be made if the sign of the discrepancies between the original workpiece and workpiece data is such that material needs to be added to the tool for correction.

Another object of the present invention is therefore to provide a uniform software solution (computer program product) for tool correction. It is also an object of the invention to provide a tool correction, in which the tool manufactured in the previous step can be used further.

It is also an object of the invention to provide a solution, so that in the first correction loop always takes a removal of the tool.

To solve the invention, on the one hand, that as many as possible of the steps to be performed for the tool correction are integrated within a uniform software solution. The tool production and the workpiece production itself are not necessarily part of the tool correction in the context of the present invention. The conversion of the setpoint data of the tool into the machine-tool-readable control commands (G-code) and the production of the tool and workpiece are thus performed either separately by the respective machine or the associated software, but can also be done together with the software provided for the tool offset ,

According to the invention, the tool offset itself comprises at least measurement of the workpiece produced with the tool (workpiece actual data such as point cloud with measuring points or surface measuring points), the calculation of the deviations between the workpiece actual data of the produced workpiece and the target data of the workpiece (workpiece target data) and from this either adaptation of the setpoint data of the workpiece and from this calculation of the adjusted setpoint data of the tool or direct adaptation of the setpoint data of the tool in one or more correction loops. In addition, it is also provided that the conversion of the setpoint data such as the CAD model of the workpiece into the desired data of the tool (in the form of CAD data such as nurbs or in the form of the STL data derived therefrom) is part of the tool offset.

On the other hand, the invention provides for a method for tool correction which can be carried out independently or in combination with the previously mentioned solution, in which an allowance is taken into account in at least the first production of the tool so that an abrasive machining of the tool is ensured at least in the first correction loop. This can for example be done by the allowance of the target data for the Tool is locally variable or installed globally. The workpiece produced in the first loop is then too small, resulting in a negative correction, ie an ablation for the tool too large in the first correction loop.

In order to ensure reliable removal even in the following correction loops, the invention also provides, as an independent or combinable solution, that the deviations or the correction vectors, in particular the mirrored deviations, are scaled. The scaling factor can be locally different, for example, depending on the function of the corresponding point on the workpiece, or global fix. For example, the correction vectors may be multiplied by a factor less than 1 before the corrected target data is created. This in turn creates an oversize on the tool.

• - bei Messung des Werkstücks die Korrekturen zur Ermittlung korrigierter Werkstück-Solldaten verwendet werden und aus den korrigierten Werkstück-Solldaten die korrigierten Werkzeug-Solldaten ermittelt werden, oder
• - bei Messung des Werkzeugs die Korrekturen zur Ermittlung der korrigierter Werkzeug-Solldaten verwendet werden, wobei die korrigierten Werkzeug-Solldaten für die Nachbearbeitung des Werkzeugs, beispielsweise Nachschleifen, oder die Herstellung eines korrigierten Werkzeugs zur Verfügung gestellt werden, wobei die Schritte:
• - Erzeugen der Messpunkte (Istdaten) durch dimensionelle Messung, insbesondere Steuerung eines Koordinatenmessgerätes
• - Einlesen der Solldaten, insbesondere Einlesen der Werkstück-Solldaten,
• - Vergleich der Istdaten mit den Solldaten des Werkstücks oder Werkzeugs und Ermittlung der Abweichungen (Abweichungsvektoren),
• - Berechnung der Korrekturen (Korrekturvektoren), vorzugsweise durch Invertierung bzw. Spiegelung der Abweichungen an den jeweiligen Solldaten,
• - Berechnung der korrigierten Werkstück-Solldaten und/oder Berechnung der korrigierten Werkzeug-Solldaten, vorzugsweiser Berechnung der korrigierten Werkzeug-Solldaten aus den korrigierten Werkstück-Solldaten, durch ein einheitliches Computerprogrammprodukt gesteuert werden, wobei vorzugsweise auch der Schritt der Erzeugung der Werkzeug-Solldaten aus den Werkstück-Solldaten umfasst ist.

The invention provides for solving a method for determining and applying a correction of a tool (tool offset), wherein the tool for producing a workpiece is usable, and wherein measuring points (point cloud) by dimensional measurement of the workpiece (workpiece actual data) or the Production of the workpiece provided tool (actual tool data) are determined, preferably by measuring with a coordinate measuring machine, more preferably with a plurality of sensors (multi-sensor coordinate measuring device) and / or a computer tomography sensor comprehensive coordinate measuring machine, and wherein the actual data (actual workpiece data or tool actual data ) and deviations (deviation vectors) are determined, which is characterized in that from the deviations corrections (correction vectors) are calculated, preferably the deviations to the respective S Inverted, ie mirrored, and the corrections are used directly or indirectly to determine corrected tool target data by:

• - When measuring the workpiece, the corrections are used to determine corrected workpiece target data and determined from the corrected workpiece target data, the corrected tool setpoint data, or
• when the tool is measured, the corrections are used to determine the corrected tool target data, the corrected tool target data being made available for reworking the tool, for example re-sharpening, or producing a corrected tool, the steps being:
• - Generating the measuring points (actual data) by dimensional measurement, in particular control of a coordinate measuring machine
• Reading the setpoint data, in particular reading in the workpiece setpoint data,
• Comparison of the actual data with the desired data of the workpiece or tool and determination of the deviations (deviation vectors),
• Calculation of the corrections (correction vectors), preferably by inverting or mirroring the deviations at the respective target data,
• - Calculating the corrected workpiece target data and / or calculation of the corrected tool target data, preferably calculation of the corrected tool target data from the corrected workpiece target data, controlled by a single computer program product, preferably also the step of generating the tool target data from The workpiece target data is included.

When mirroring the deviations in the respective target data, it is inventively provided that a patch selection is additionally integrated in order to ensure a correct patch assignment of the actual points. This means that the measuring points which are assigned to the respective area element (patch) are automatically selected from the measured actual data, the patches preferably being taken from the nominal data. In particular, the invention is characterized in that the deviations determined (deviation vectors), in particular deviations between the workpiece actual data and the workpiece target data or corrected workpiece target data, as a deviation element in STL format or CAD format in the computer program product for further processing be made available, in particular for the correction of the workpiece target data.

Preferably, it is provided that a plurality of correction loops are performed iteratively, with respectively determined deviations being used for the correction of the setpoint data corrected in the respective previously executed loop.

In particular, the invention is characterized in that the computer program product converts the tool setpoint data and / or the corrected tool setpoint data into machine-readable control codes such as G-code.

Preferably, the invention provides that the computer program product the generated G-code for controlling the for the production of Tool used machine tool used, in particular machine tool controls.

It should also be emphasized that a locally variable or globally fixed oversize, which is preferably calculated from the desired workpiece data of the workpiece which is to be produced with the tool, is calculated when calculating the tool target data that can be used for the production of a tool is attached to the tool target data, so that from the corrected tool target data, which are calculated from the deviations of the workpiece target data or determined in the previous correction step corrected workpiece target data to the workpiece actual data, at least in the first correction loop of a tool offset a removal of the tool results.

The invention is also characterized in that in the calculation of the usable for the production of a tool setpoint data, preferably calculated from the workpiece target data of the workpiece to be produced with the tool, an allowance is calculated, which preferably at the Tool setpoint data is attached, so that from the corrected tool setpoint data, which are calculated from the deviations of the workpiece setpoint data or corrected workpiece setpoint data determined in the previous correction step to the workpiece actual data, for the first or further correction loops of a tool offset Removal of the tool results by locally scaling the measured deviations and / or the correction vectors determined therefrom variably or globally, preferably with a factor smaller than 1.

The subject matter of an independent invention is a method for the determination of surface measurement points according to the autofocus or focus variation method.

In the known methods for the determination of surface measurement points after the autofocus or focus variation method, the image acquisition takes place with a fixed magnification (or imaging scale) and a fixed movement speed. For accurate measurements of the coordinate of a surface measuring point in the imaging direction of the optics must be selected with a low depth of field optics, so a high magnification, and it must be set a low movement speed during image acquisition to a high resolution in the measuring direction (imaging direction) and a to achieve low motion blur in the pictures. Corresponding optics provide for the determination of focus curves and the coordinates of the surface measuring points formed therefrom necessary evaluable contrast or brightness differences only in a very small range in the imaging direction (ie direction of the optical axis of the optical system used).

This results in the disadvantage that unknown surfaces can be measured accurately only very time consuming, because to find the surface safely, a large distance must be selected for the start of image acquisition.

Even if zoom optics are used with variable zoom level, ie magnification or magnification, so far only methods are known in which in a first measurement with a small magnification, the position of the surface roughly found ("caught") and in a second measurement with changed accordingly Starting position in the imaging direction and larger magnification, the exact detection of the surface takes place. Due to the necessity of two measurements, the disadvantage of the high time requirement remains.

It is therefore another object of the present invention to obviate the drawbacks of the prior art and to allow accurate measurement by the autofocus or focus variation method with reduced time requirements. In particular, it is also an object of the invention to reliably detect unknown surfaces, that is, surfaces that are not precisely known in the imaging direction.

To solve the problem, the invention provides a two-stage or multi-stage process in which the magnification is increased during the movement on the surface, wherein a rough estimate of the position of the surface in the imaging direction from the extrapolation of first recorded images with a low magnification and preferably Movement speed is gradually reduced in the imaging direction.

• - Lange Suchwege: Der Start der Bildaufnahme kann weit oberhalb oder unterhalb der erwarteten Oberfläche starten, um diese sicher zu erfassen.
• - Hohe Genauigkeit durch hohe Zoomstufe (großer Abbildungsmaßstab) und ggf. geringe Bewegungsgeschwindigkeit nahe und am Fokusort, wodurch eine hohe Auflösung in und senkrecht zur Abbildungsrichtung erreicht wird.
• - Die genaue Messung ist in einem Messzyklus, also einer Bewegung möglich. Es ist nicht notwendig, die Lage der Oberfläche in Abbildungsrichtung erst grob zu detektieren („fangen“) und dann noch einmal mit vergrößertem Abbildungsmaßstab und geringerer Bewegungsgeschwindigkeit in Abbildungsrichtung genau zu messen. Dadurch ergibt sich eine enorme Zeitersparnis ohne Genauigkeitsverlust.

This results in the following advantages:

• - Long search paths: The start of the image acquisition can start far above or below the expected surface in order to capture them safely.
• - High accuracy due to high zoom level (large magnification) and possibly low movement speed near and at the focus location, whereby a high resolution in and perpendicular to the imaging direction is achieved.
• - The exact measurement is possible in a measuring cycle, ie a movement. It is not necessary to roughly detect the position of the surface in the imaging direction ("catch") and then again with enlarged Precisely measure magnification and slower movement speed in the imaging direction. This results in an enormous time savings without loss of accuracy.

• - Aufnahme von mehreren Bildern mit einer Kamera und dieser zugeordneter Optik in unterschiedlichen Abständen in Abbildungsrichtung der Optik zwischen Werkstückoberfläche und Scharfebene der Optik, wobei die Bildaufnahme während der Änderung des Abstandes erfolgt,
• - Aufzeichnung der jeweils eingestellten Abstände zum Zeitpunkt der Bildaufnahme,
• - Untersuchung der Helligkeit und/oder des Kontrastes, oder daraus abgeleiteter Größen wie Änderung derselben, der Bilder oder korrespondierender Abschnitte der Bilder, vorzugsweise Pixel, entlang des Abstandes, wobei zusammen mit den aufgezeichneten Abständen eine zumindest erste Fokuskurve bzw. erste Fokuskurven gebildet werden,
• - Ermittlung der Lage des dem Bild oder dem jeweiligen Bildabschnitt zugeordnet Oberflächenpunktes in Abbildungsrichtung der Optik (Fokusort bzw. Fokusorte) aus der jeweiligen Fokuskurve, vorzugsweise anhand des Maximums der Fokuskurve bzw. jeweiligen Fokuskurve,

dass sich dadurch auszeichnet, dass die Optik als Zoomoptik mit veränderbarem Abbildungsmaßstab ausgebildet ist und folgende Schritte ausgeführt werden:

• - Aufnahme erster Bilder mit erstem Abbildungsmaßstab β1 und erster Abstandsänderungsgeschwindigkeit v1 und daraus Extrapolation einer ersten Fokuskurve oder jeweils erster Fokuskurven und Bestimmung ersten Fokusorts oder erster Fokusorte für die Abschnitte,
• - Aufnahme zweiter Bilder in im Vergleich zu den ersten Bildern geringerer Entfernung zum ersten Fokusort oder einem der ersten Fokusorte, und mit zweitem Abbildungsmaßstab β2, wobei β2 > β1 ist, wobei vorzugsweise zweite Bilder während zweiter Abstandsänderungsgeschwindigkeit v2 aufgenommen werden, wobei v2 < v1 ist,
• - Bestimmung des zweiten Fokusortes bzw. der zweiten Fokusorte aus der bzw. den aus den zweiten Bildern ermittelten Fokuskurven,
• - vorzugsweise iterative Verwendung der zweiten oder weiteren Fokusorte um dritte oder weitere Bilder mit jeweils noch größerem Abbildungsmaßstab β und vorzugsweise jeweils noch geringerer Geschwindigkeit v aufzunehmen, und um aus den dritten oder weiteren Bildern dritte oder weitere Fokuskurven und daraus dritte oder weitere Fokusorte zu ermitteln,
• - Verwendung der zweiten oder gegebenenfalls vorhandenen dritten oder weiteren Fokusorte als in Abbildungsrichtung liegende Lage bzw. Koordinate des jeweiligen Oberflächenmesspunktes.

The invention provides for the solution a method for the determination of surface measuring points according to the autofocus or focus variation method, preferably with an optical sensor arranged in a coordinate measuring machine, particularly preferably an image processing sensor, with the following steps:

• - Recording of multiple images with a camera and this associated optics at different distances in the imaging direction of the optics between the workpiece surface and focal plane of the optics, wherein the image is recorded during the change of the distance,
• - recording of the respectively set distances at the time of image acquisition,
• Examination of the brightness and / or the contrast, or variables derived therefrom, such as changes in the images, or corresponding sections of the images, preferably pixels, along the distance, forming an at least first focus curve or first focus curves together with the recorded distances,
• Determination of the position of the surface point associated with the image or the respective image section in the imaging direction of the optical system (focus location or focal locations) from the respective focus curve, preferably based on the maximum of the focus curve or respective focus curve,

that is characterized in that the optics is designed as zoom optics with a variable magnification and the following steps are carried out:

• Recording first images with first image scale β1 and first distance change velocity v1 and, therefrom, extrapolation of a first focus curve or respective first focus curves and determination of first focal location or first focal locations for the sections,
• - Recording second images in comparison to the first images closer distance to the first focus location or one of the first focus locations, and with second magnification β2, where β2> β1, preferably second images are taken during second distance change rate v2, where v2 <v1 .
• Determination of the second focus location or of the second focus location from the focus curve (s) determined from the second images,
• preferably iterative use of the second or further focus locations to record third or further images, each with a still greater magnification β and preferably even lower velocity v, and to determine third or further focus curves from the third or further images and third or further focal locations therefrom,
• Use of the second or possibly existing third or further focus locations as a position or coordinate of the respective surface measurement point lying in the imaging direction.

In particular, the invention is characterized in that first and second images are successively taken in a direction of movement, wherein the switching of the magnification scale in the movement or during an intermediate stop of the movement takes place.

Preferably, it is provided that the number of first images is at least three, preferably at most 10.

In particular, the invention is characterized in that the recording of the first images starts at a safe distance from the expected focus location and takes place at a higher speed v1 than for the speed v2 or v intended for recording the images for determining the surface measurement points.

Preferably, the invention provides that the zoom optics at least one, preferably at least two movable lenses or lens groups, preferably for adjusting working distance, ie position of the focal plane relative to the optics, and magnification, particularly preferably for independent adjustment of working distance and magnification.

• - Bewegung der Einheit aus Kamera und Optik, und des Werkstücks relativ zueinander oder
• - Bewegung der Kamera relativ zur Optik oder
• - Bewegung der Optik oder zumindest einer Linse der Optik relativ zur Kamera und dem Werkstück oder
• - Änderung der Brennweite zumindest einer Linse der Optik, wobei die Linse als Linse mit einstellbarer Brennweite ausgebildet ist, vorzugsweise Flüssiglinse oder Linse mit akustisch modulierbarer Brennweite.

It should also be emphasized that the different distances are set by:

• - Movement of the unit of camera and optics, and the workpiece relative to each other or
• - Movement of the camera relative to the optics or
• Movement of the optics or at least one lens of the optic relative to the camera and the workpiece or
• - Changing the focal length of at least one lens of the optics, wherein the lens is designed as a lens with adjustable focal length, preferably liquid lens or lens with acoustically modulated focal length.

As the lens with adjustable focal length are liquid lenses or the like, for example, a lens with acoustically modulated focal length ("Tunable acoustic gradient index of refraction lens") provided.

The subject matter of an independent invention is an apparatus and a method for optical-chromatic distance measurement of a workpiece surface with a plurality of measuring beams distributed on at least one line.

Optical-chromatic distance sensors with a plurality of measuring beams distributed along a line are known, for example, from US Pat DE 10 2016 123 403.6 the applicant known. To increase the resolution in the line direction (lateral resolution), ie transversely to the preferred scanning direction, it is proposed to move the measuring line slightly rotated around the measuring direction. It is also proposed to arrange the measuring channels on several lines in a matrix.

By previously mentioned twisting the direction of movement with respect to the preferred scanning direction (which is perpendicular to the line direction), there is the disadvantage that a large increase in the lateral resolution can be achieved only with a very large angle of rotation. In addition, there is a directional dependence of the lateral resolution, which is dependent on the mounting angle of the sensor to the measuring direction. In particular, for coordinate measuring machines with rotatable about a rotation axis turntables for workpiece holder, for example, for tool measurement, but the movement and scanning direction must be flexible, for example, to be able to measure with high resolution advantageously advantageous left and right tools. The preferred scanning direction is not necessarily the direction of movement during the measurement. The direction of movement may also have an angle with respect to the scanning direction, which is usually less than 45 °, but may be larger. The direction of movement is determined by the position of the characteristics of the workpiece or tool to be measured, for. B. by the location of a cutting edge of a tool. However, the lateral resolution is considered in relation to the perpendicular to the scanning direction (in the case of a line this is the perpendicular to the line direction), which is perpendicular to the measuring direction. The resolution in the scanning direction is practically freely adjustable due to the movement speed. Transversely, the lateral resolution results from the distance between the measuring beams and the direction of movement. However, since the direction of movement can be predetermined differently by the position of the features, a high lateral resolution may not be achieved.

In the case of the matrix-type arrangement, the resolution remains constant without twisting the direction of movement, so that the aforementioned disadvantages also result.

It is therefore an object of the present invention to increase the lateral resolution along the original line direction or perpendicular to a scanning direction, preferably with an increased lateral resolution in a plurality of scanning directions, particularly preferably in as many scanning directions as possible.

To solve the invention provides that a plurality of mutually parallel lines offset perpendicular to the line direction and additionally offset in the line direction by a fraction of the distance of the measuring beams are arranged in the direction of the lines. The offset perpendicular to the line direction, for example, correspond to the distance of the measuring beams in the line direction. The offset in the line direction can be, for example, 1/2, 1/3, 1/4, 1/5, 1/6, 1/7 or 1/8 etc. of the distance of the measurement beams in the line direction.

Another solution is to twist several measuring lines around the measuring direction, z. B. to arrange crosswise, so to arrange two measuring lines perpendicular to each other. With regard to the preferred scanning direction, in a particularly preferred embodiment, both lines each form an angle of 45 ° to the scanning direction. In addition, the measuring lines that are twisted relative to one another are in each case arranged displaced in the line direction and / or the mounting angle of the sensor around the measuring direction is selected such that a lateral resolution generated by all the measuring beams is obtained with respect to a predetermined scanning direction perpendicular to the measuring direction is the lateral resolution due to the distance of the measuring beams on one line.

For the use of the sensor in a coordinate measuring machine with a workpiece such as tool receiving rotating about a rotary axis turntable, the invention provides for the solution also that the measuring direction is exactly or approximately exactly perpendicular to the direction of the axis of rotation and the lateral resolution perpendicular to the measuring direction and perpendicular to Scanning direction (usually about the direction of the axis of rotation), that is increased in the direction perpendicular to the direction of the axis of rotation by either the plurality of parallel lines are arranged offset in the direction of the axis of rotation and also have the offset to each other in the line direction, which is less than that Distance of the measuring beams in the line direction, or by at least two measuring lines are rotated to each other around the measuring direction, preferably at 90 ° to each other and each 45 ° to the direction of the axis of rotation, which are particularly preferably, as explained above, also shifted in the line direction. Depending on the position or the course of the features (eg left or right-hand edged cutting edge), the direction of movement is twisted in the direction of the axis of rotation. As the preferred scanning direction the direction of the axis of rotation can be considered.

To solve the invention thus provides a device an optical distance sensor, in particular according to the chromatic or chromatic-confocal principle with a plurality of mutually offset a workpiece surface detecting measuring beams comprising before, each measuring beam for determining a distance value between the sensor and a workpiece to be measured is associated with each measuring channel, an optical fiber, and each fiber is assigned to a part of an evaluation, in particular each row of a matrix-shaped camera, wherein at least some of the measuring beams are arranged offset to each other on a first line perpendicular to the measuring direction of the measuring beams characterized in that a plurality of parallel lines of measuring beams are arranged so that the lines are mutually offset from each other in the direction perpendicular to the line direction, and in addition, an offset in line direction zueinan which is less than the distance of the measuring beams in the line direction.

As a further independent solution, the invention provides a device comprising an optical distance sensor, in particular according to the chromatic or chromatic-confocal principle with a plurality of mutually offset to a workpiece surface detecting measuring beams, each measuring beam for the determination of a distance value between the sensor and a to be measured Workpiece is assigned to a separate measuring channel, each measuring channel is associated with an optical fiber, and each fiber is assigned to a part of an evaluation, in particular each line of a matrix-shaped camera, wherein at least some of the measuring beams offset on a first line perpendicular to the measuring direction of the measuring beams to each other are distinguished, which is characterized in that at least one second line rotated about the measuring direction, in particular rotated by 90 °, is arranged to the first line, wherein preferably the mutually rotated measuring lines in each case in lines arranged direction and / or the mounting angle of the sensor is selected to the measuring direction so that with respect to a predetermined perpendicular to the measuring direction extending preferred scanning direction or direction of a generated by all the measuring beam lateral resolution is achieved, which is greater than that by the distance the measurement beams on each line conditional lateral resolution.

• - mehrere parallele Linien in Richtung der Drehachse versetzt angeordnet sind, die zusätzlich jeweils einen Versatz zueinander in Linienrichtung aufweisen, der geringer als der Abstandes der Messstrahlen in Linienrichtung ist, oder
• - zumindest zwei Messlinien zueinander um die Messrichtung verdreht sind, bevorzugt 90° zueinander und jeweils 45° zur Richtung der Drehachse, wobei vorzugsweise die bevorzugte Scanrichtung parallel zur Richtung der Drehachse verläuft.

Preferably, it is provided that the sensor is arranged in a coordinate measuring machine with a turntable which accommodates a tool and which is rotatable about an axis of rotation such that the measuring direction runs exactly or approximately exactly perpendicular to the direction of the axis of rotation, and

• - A plurality of parallel lines are arranged offset in the direction of the axis of rotation, each additionally having an offset to one another in the line direction, which is less than the distance of the measuring beams in the line direction, or
• - At least two measuring lines are rotated to each other around the measuring direction, preferably 90 ° to each other and each 45 ° to the direction of the axis of rotation, preferably the preferred scanning direction is parallel to the direction of the axis of rotation.

To solve the invention also provides a method for operating the aforementioned devices, which is characterized in that to increase the resolution in the lateral direction, ie the direction perpendicular to the measuring direction and perpendicular to a predetermined preferred scanning direction, the measuring beams of the plurality of offset and / or twisted lines arranged to be used for a common evaluation.

Preferably, it is provided that the sensor is operated in a coordinate measuring machine with a turntable for receiving a tool, wherein the measuring direction is aligned perpendicular to the axis of rotation of the turntable and preferably the preferred scanning direction is parallel to the direction of the axis of rotation.

The subject matter of an independent invention is a method for recording, displaying and evaluating an image, in particular an image processing method for a coordinate measuring machine.

From the photography so-called HDR methods (High Dynamic Range - method) are known in which images with different exposure time (or integration time of the camera used) are superimposed to a fuller contrast overall picture. The aim here is to create a perceived as subjective subjective image of a scene by too dark and too bright areas are represented in more contrast.

In dimensional metrology, in particular coordinate metrology, optical measuring methods, in particular image processing methods are known in which present in an camera recorded images edges can be evaluated to set measuring points on the recorded workpiece and to link the measuring points for the dimensional determination of dimensions. Unsolved here, however, is that in low light conditions, especially dark parts or hard to detect edges, a reliable Measurement can not be guaranteed. In this case, it should be noted in particular that the area in which an edge is to be searched usually has to be selected first by setting a window by the operator in the recorded image, which is displayed on a display unit such as a screen. In too dark or too bright (overexposed) areas, the edges are difficult or impossible to see by the operator.

A further object of the present invention is therefore to provide the operator with a contrast-enhanced representation of the image of a workpiece to be measured. It is also an object of the invention to perform on the contrast enhanced image improved edge detection.

To solve this, the invention provides that an HDR image is taken and used as the image to be displayed and possibly to be used for the generation of measuring points at edge transitions.

In the HDR image, dark areas are lightened and any areas that are outshone are avoided, ie darkened, by removing the corresponding partial areas of the image either from an image with a high or low amount of light present on the image. This results in a better recognizability of the areas in which edges are present and the operator can more easily select the areas provided for the generation of measuring points and set suitable measuring windows.

But also for the dimensional evaluation, ie the generation of the measuring points by edge finding, advantages result from the use of the HDR image. It should be noted, however, that the composition of the image information from the images taken with different amount of light per image takes place in a correspondingly scaled form, so that the intensity ratios between the individual pixels are maintained. This is usually given due to the higher dynamics in the HDR images. An HDR image has a correspondingly higher resolution (bit depth).

In the subsequent edge finding, in particular, dark pixels with less noise are used in comparison to a picture taken with a single amount of light. In this way, the edge location and thus the position of the measuring point can be determined more accurately.

According to the invention, the method is used in particular in optical coordinate measuring machines. These use, for example, image processing sensors. After a particularly noteworthy expression, the insert is provided in a coordinate measuring machine designed as a measuring microscope. In this, the workpiece to be examined is placed on a measuring table, above or below which there is a mostly magnifying or reducing optics with a camera arranged thereafter. However, the method can also be used in coordinate measuring machines, in which the measuring table with the workpiece and the unit of optics and camera are moved relative to each other in one, two or three directions.

The invention provides for the solution a method for recording, display and evaluation of an image, preferably used in a measuring microscope or optical coordinate measuring machine with image processing sensor, wherein at least one image is taken with a camera, an image on an output means, such as screen, for the operator and the operator selects on the basis of the representation the areas where measurement points are to be determined, and wherein the evaluation at least the determination of one or more measurement points on one or more detected by at least one image edges of a workpiece by means of an edge detection method, wherein the evaluation Preferably, the dimensional linking of several measuring points to dimensions comprises that it is characterized in that a high-dynamic-range image (HDR image) is generated from a plurality of images recorded with the camera, which is used for the display on the display means and / or which is used for the determination of the measuring points.

In particular, the invention is characterized in that for the generation of the HDR image with the camera a plurality of images with different amount of light per image are recorded and assembled, the images of different amounts of light are generated by different light levels of one or more provided for the illumination of the workpiece Light sources, in particular bright field incident light exposure source and / or dark field Auflichtbelichtungsquelle and / or transmitted light exposure source are set and / or by different illumination directions, in particular a dark field Auflichtbelichtungsquelle with a plurality of at least partially annular distributed segments, set and / or by different integration times of Camera are adjusted and / or by different numbers of recorded images, preferably sequentially recorded images are added in their gray values.

Preferably, it is provided that the composition of the image information (gray values of the pixels of the image) to the HDR image from the several images are taken by each image only the image areas (pixels) are removed, which are neither overexposed nor too dark and / or exceed a minimum contrast, wherein when composing the gray values of the image areas are scaled to each other according to the amount of light associated with each image.

Further details, advantages and features of the invention will become apparent not only from the claims, the features to be taken from them - alone and / or in combination - but also from the following description of the figures.

• 1 eine Prinzipdarstellung der erfindungsgemäßen Vorrichtung, einer Zoomoptik mit einem optischen Abstandsensor in einer ersten Ausgestaltung,
• 2 eine Prinzipdarstellung der erfindungsgemäßen Vorrichtung, einer Zoomoptik mit einem optischen Abstandsensor in einer zweiten Ausgestaltung,
• 3 eine Prinzipdarstellung in einer ersten Ausgestaltung der auf mehreren Linien verteilten Messstrahlen einer erfindungsgemäßen Vorrichtung eines optischen Abstandsensors und
• 4 eine Prinzipdarstellung in einer zweiten Ausgestaltung der auf mehreren Linien verteilten Messstrahlen einer erfindungsgemäßen Vorrichtung eines optischen Abstandsensors.

Show it:

• 1 1 is a schematic representation of the device according to the invention, a zoom lens with an optical distance sensor in a first embodiment,
• 2 a schematic diagram of the device according to the invention, a zoom lens with an optical distance sensor in a second embodiment,
• 3 a schematic diagram in a first embodiment of the distributed on several lines measuring beams of an apparatus according to the invention of an optical distance sensor and
• 4 a schematic diagram in a second embodiment of the distributed on several lines measuring beams of an inventive device of an optical distance sensor.

Based on 1 the device according to the invention is exemplified. The optical sensor head 1 contains the optics 2 which in turn comprises an object-side lens presystem 3 , here consisting of two lenses, a zoom lens system 4 with the example here two in the imaging direction 9 parallel to the arrows 4a ' respectively. 4b ' sliding zoom lenses 4a and 4b , and more picture lenses 14 , The optical distance sensor is at least partially integrated in the sensor head 5 whose the measuring beam 6 leading fiber 7 the central opening 8th the first zoom lens 4a is supplied. In the illustrated embodiment, the fiber runs 7 through the gap 10 in the opening 8th and ends approximately at the object-side end of the zoom lens 4a , so that the measuring beam at the fiber end 7a in the direction of the workpiece to be measured 13 the fiber 7 leaves and after the reflection on the workpiece can at least partially reenter. The fiber end 7a is with the zoom lens 4a firmly connected, so in the opening 8th fixed, z. B. glued, and together with this in the imaging direction 9 displaceable. The drives required for this purpose are, for example, with the zoom lens 4a connected, but not shown here.

The optical distance sensor is preferred 5 designed as a chromatic confocal single-point sensor. At least one of the lenses of the lens presystem 3 has a targeted chromatic aberration (chromatic aberration), so that the different wavelengths of the measuring beam 9 at different distances in the direction of the workpiece 13 to be focused. As well as the measuring radiation reflected by the workpiece 9 not exactly back to the fiber end for all sharp-focused wavelengths 7a be focused, the invention provides the fiber end 7a , in particular together with the zoom lens 4a in the imaging direction 9 nachzuführen accordingly, for example, when using the optical distance sensor 5 in scanning mode. Alternatively, it is also provided, the fiber end 7a to leave fixed and the position of the image-side focal plane of the lens presystem 3 on the fiber end 7a adjust. For this purpose, the focal length of at least one of the lenses of the lens presystem 3 adapted by this example, designed as a liquid lens. For a very fast tracking is possible, as required in the aforementioned scanning operation.

The movement of the zoom lens 4a in imaging direction 9 but is also needed to the magnification and the working distance of the identical optics 2 using the image processing sensor 11 adjust. This has to further further imaging lenses 14 on, the light originating from the workpiece on the image acquisition unit 12 like CCD or CMOS camera of the image processing sensor 11 map. Will the optical sensor head 1 as an image processing sensor 11 operated, so must in particular the zoom lens 4a be moved to a different position along the imaging direction 9, as when in the 1 illustrated operation of the optical distance sensor 5 , When operating the optical sensor head 1 as an image processing sensor 11 is also provided according to the invention, one on the workpiece 13 Directional lighting such as bright field lighting in the optics 2 einzuspiegeln. This can, for example, before or after the lens presystem 3 respectively. It can also be a brand projection. The reflection of the beam path of a further optical distance sensor such as Foucault sensor is also provided, for example between zoom lens system 4 and picture lenses 14 ,

In the 2 a further embodiment of the device according to the invention is exemplified. In comparison to 1 the reflection of the chromatic sensor takes place 5b designed optical distance sensor by a beam splitter 15 , From the fiber end 7b becomes the measuring radiation 6b in the direction of the beam splitter 15 delivered and from this on the workpiece 13 deflected, reflected at this and the beam splitter 15 back to the fiber end 7b directed. One of the two lenses 16 . 17 of the lens presystem 3 , prefers the lens 16 is intentionally designed with a chromatic aberration, and more preferably an asphere, to achieve the function of the chromatic sensor. For the wavelength-dependent adjustable re-focusing of the measuring beam 6b in the fiber end 7b is one of the two lenses 16 . 17 of the lens presystem 3 , prefers the lens 17 designed as adjustable in their focal length. Alternatively or additionally, the invention also provides, the lens 17 displaceable in the imaging direction 9 or the fiber end 7b slidable to optimize the re-focusing.

Based on 3 and 4 Two preferred embodiments of the measuring beams distributed over several lines of an apparatus according to the invention for an optical distance sensor are shown.

In 3 become the multiple lines 10 . 11 . 12 . 13 parallel to each other, ie perpendicular to the line direction in the direction of the line 15 arranged offset and also have an offset in the line direction or original line direction 14 on, wherein the offset is smaller than the distances of the measuring beams 10a to 10b respectively. 10b to 10c etc. in line direction 14 for example, the original first line 10 , By way of example, an offset in the line direction of about 1/4 of the distance of the measuring beams was selected on a line, whereby the direction of scanning is determined 13 a 4-fold lateral resolution in the line direction 14 results. For the direction of movement 16 slightly different from the originally intended scanning direction 13 (deviates with a line), nevertheless the increased lateral resolution remains in the direction 14 , and also still increased lateral resolution in the direction perpendicular to the direction of movement 16 , This ensures that even for any position to be measured features and thus determined directions of movement increased lateral resolution can be achieved.

In the 4 are the two lines 10 and 11 arranged at an angle of 90 ° to each other around the measuring direction (perpendicular to the plane of the drawing). In addition, one of the lines 10 respectively. 11 shifted in the line direction by an amount that is less than the distance of the measuring beams 10a to 10b respectively. 10b to 10c etc. in the line direction of, for example, the original first line 10 , For the scanning direction 13 This results in an increased lateral resolution perpendicular to the scanning direction or for the direction of movement 16 perpendicular to this.

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

• DE 102011056819 [0002]
• EP 2668464 [0005]
• EP 1071922 [0021]
• EP 1299691 [0021]
• US 4710876 [0047]
• EP 1861822A1 [0048]
• DE 102013109632 [0049]
• DE 102015121582 [0064]
• EP 2313867 [0067]
• DE 102016123403 [0103]

Claims (14)

Method for determining the position of one or more regions on one or more cutting edges or teeth or other features distributed on the circumference of a tool, preferably on peripherally distributed features on a tool, the cutting edge depending on the axial position along the The tool axis in some different rotational positions, the tool thus has in particular twisted cutting edges or features, wherein the determination by image processing sensor, in particular in a coordinate measuring machine integrated image processing sensor, preferably with illumination in transmitted light and / or bright field incident light and / or dark field reflected light, wherein Images are recorded in several rotational positions of the tool around its tool axis and in several relative positions between the tool and image processing sensor in the direction of the tool axis, and by evaluating the recorded images, the areas in the image d or in the resulting images, which are generated by superimposing and / or juxtaposing the individual images, are determined and investigated, in which the cutting edge or features are sharply imaged, in particular by evaluating the perpendicular distance to the position of the tool axis and / or by evaluating the Image contrast, characterized in that the rotational movement and the axial movement, ie in the direction of the tool axis, are controlled in such a way that the cutting edge or the feature is followed in its preferably twisted or helical expression, the movement speed in the axial direction so regulated is that the respective sharply imaged region of the cutting edge or the feature in case of change, preferably continuous change, the rotational position always remains within the area detected by the image processing sensor, preferably remains centered, particularly preferably in a zul defined by the image center lar portion remains. An optical sensor head (1) comprising an optical system (2) which comprises at least one object-side lens system (3) and a zoom lens system (4) with one or more zoom lenses (4a, 4b) displaceable in the imaging direction, wherein the optical sensor head (1) further comprises a optical distance sensor (5) comprising an optical fiber (7) which feeds the measuring beam (6) of the optical distance sensor (5), characterized in that a first zoom lens (4a) has a central opening (8) forming the optical fiber (5). 7) and that the object-side end (7a) of the fiber (7), preferably together with the first zoom lens (4a), is designed to be displaceable in the imaging direction (9). Optical sensor head (1) comprising an optical system (2) and an optical distance sensor (5b), preferably a chromatically confocal distance sensor designed as a chromatic distance sensor, whose measuring beam (6b) is reflected into the optical system (2) starting from a fiber end (7b), Preferably, by means of a beam splitter (15), and wherein on the object side of the reflection (15) a lens (16, 17) of a lens system (3) with a chromatic aberration is arranged, and preferably on the image side of the reflection (15) a zoom lens system (4 ), characterized in that the pre-lens system (3) has a lens (17, 16) displaceable in the imaging direction (9) or as in its focal length adjustable lens such as liquid lens and for focusing of the workpiece (13) most reflected Part of the measuring beam (6b) in the object-side fiber end (7b) is formed. Method for determining geometric features on a workpiece, in particular determination of measuring points, with the device according to at least one of the preceding Claims 2 or 3 , characterized in that selectively either object-side end of the fiber, preferably together with the first zoom lens is moved in the imaging direction in a first position in which the object-side end of the fiber is arranged in the image-side focal point of the lens presystem to record measuring points with the optical distance sensor , or the one or more zoom lenses are moved in the imaging direction in positions to adjust working distance and / or magnification for the image processing sensor and detected with the image processing sensor contours of the workpiece and measuring points are determined or with the image processing sensor by means of focus variation method images of the workpiece at different distances between Workpiece and object-side focal point of the optics are detected and determined by contrast or brightness evaluation measurement points. Method according to preferably Claim 4 Characterized in that during the measurement with the designed as a chromatic sensor optical distance sensor, the light reflected by the workpiece measuring beam receiving end of the fiber in the imaging direction of the optics of the position of the wavelength-dependent image-side focal point of the measuring beam imaging on the workpiece Linsenvorsystems or the wavelength-dependent image-side focal point of the Linsenvorsystems in the imaging direction of the position of the fiber end for the wavelength (color) of each of the measuring object or workpiece most reflected portion of the measuring beam is tracked, wherein the optical distance sensor is preferably operated in the scanning mode. Method for determining contours, in particular contour points, on a measurement object, in particular workpiece by image processing, in particular 2D image processing, wherein the contours or contour points with higher resolution of the contour point positions from the gray values of the pixels of the respective image (gray value amplitudes) than through the pixel center distances of the image determined and / or taking into account the gray values in the vicinity of the respective contour point, are determined by first the positions of first contour points are determined by the gray values of all or part of the pixels of the image at least a first global operator, preferably global threshold operator or global Differential operator is applied and the global threshold used or the global threshold amplitude is provided, characterized in that subsequent to the area of the image in the local environments of the first contour point the following steps are used: determination of at least one local reference gray-scale amplitude from the gray-scale amplitudes of the pixels in the vicinity of the first contour points and preferably at least one global reference gray-scale amplitude from the gray-scale amplitudes of the pixels of the image, adaptation of the gray values of the pixels, the gray values of the pixels in each of the local environment of the first contour points are normalized using at least the local reference gray value amplitudes, preferably such that with a global operator, such as global threshold operator or global differential operator, the same second contour points can be calculated as by applying the respective local reference gray value amplitudes as a threshold for a local operator, such as local threshold operator or local differential operator, application of at least one second global operator, preferably global threshold operator or global differential op to the adjusted gray values of all or part of the pixels of the image for determining second contour points - use of the determined second contour points as contours or contour points. Method for determining and applying a correction of a tool (tool offset), the tool being usable for the production of a workpiece, and measuring points (point cloud) by dimensional measurement of the workpiece (workpiece actual data) or of the tool provided for the production of the workpiece (tool Actual data) can be determined, preferably by measuring with a coordinate measuring machine, particularly preferably with a multi-sensor coordinate measuring machine and / or a computer tomography sensor comprehensive coordinate measuring machine, and wherein the actual data (actual workpiece data or tool actual data) with the associated target data (workpiece Desired data or desired tool data) and deviations (deviation vectors) are determined, characterized in that from the deviations corrections (correction vectors) are calculated, wherein preferably the deviations are inverted to the respective target data, that is mirrored, un the corrections are used directly or indirectly for determining corrected tool setpoint data by: - using the corrections for determining corrected workpiece setpoint data when measuring the workpiece, and determining the corrected tool setpoint data from the corrected workpiece setpoint data, or - at Measurement of the tool, the corrections are used to determine the corrected tool target data, wherein the corrected tool target data for post-processing of the tool, such as regrinding, or the production of a corrected tool are provided, the steps: - generating the measuring points ( Actual data) by dimensional measurement, in particular control of a coordinate measuring machine - reading the target data, in particular reading the workpiece target data, - Comparison of the actual data with the desired data of the workpiece or tool and determination of the deviations (deviation vectors), - Calculation of the correction (Correction vectors), preferably by inverting or mirroring the deviations of the respective target data, - Calculation of the corrected workpiece target data and / or calculation of the corrected tool setpoint data, preferably calculation of the corrected tool setpoint data from the corrected workpiece target data, by a uniform computer program product to be controlled, wherein preferably also the step of generating the desired tool data from the workpiece target data is included. Method according to preferably Claim 7 , characterized in that in the calculation of the usable for the production of a tool tool set data, preferably calculated from the workpiece target data of the workpiece to be manufactured with the tool, a locally variable or globally fixed oversize is calculated, which preferably at the tool target data is applied, so that from the corrected tool target data, which are calculated from the deviations of the workpiece target data or corrected in the previous correction step corrected workpiece target data to the workpiece actual data, at least in the first correction loop of a tool offset Removal of the tool results. Method according to preferably Claim 7 or 8th , characterized in that in the calculation of usable for the production of a tool desired tool data, preferably calculated from the workpiece target data of the workpiece to be manufactured with the tool, an allowance is calculated, which is preferably attached to the tool target data is, so that from the corrected tool target data, which are calculated from the deviations of the workpiece target data or determined in the previous correction step corrected workpiece target data to the workpiece actual data for the first or further correction loops of a tool offset results in a removal of the tool in that the measured deviations and / or the correction vectors determined therefrom are locally variably or globally fixed scaled, preferably with a factor smaller than 1. Method for determining surface measuring points according to the autofocus or focus variation method, preferably with an optical sensor, particularly preferably an image sensor, arranged in a coordinate measuring machine, comprising the following steps: recording a plurality of images with a camera and associated optics at different distances in the imaging direction of the optical system between the workpiece surface and focal plane of the optics, wherein the image acquisition takes place during the change of the distance, - recording of the respectively set distances at the time of image acquisition, - examination of the brightness and / or the contrast, or derived variables such as change of the same, the images or corresponding sections of the Images, preferably pixels, along the distance, wherein together with the recorded distances, an at least first focus curve or first focus curves are formed, - Determining the position of the image or the respective en image section associated surface point in the imaging direction of the optics (focus or focus locations) from the respective focus curve, preferably based on the maximum of the focus curve or respective focus curve, characterized in that the optics is designed as a zoom lens with variable magnification and the following steps are performed: - Recording first images with first magnification β1 and first distance change velocity v1 and therefrom extrapolation of a first focus curve or respectively first focus curves and determination of first focus location or first focal locations for the sections, recording second images in relation to the first images closer to the first focus location or one the first focal point, and with second magnification β2, where β2> β1, preferably taking second images during the second distance change rate v2, where v2 <v1, - determining the second focus location or the second focus locations from the or the second images determined focus curves, - preferably iterative use of the second or further focus locations to third or more images with even greater magnification β and preferably each still lower speed v record, and from the third or further Determine third or further focus curves and third or further focus locations therefrom, use of the second or possibly existing third or further focus locations as the position or coordinate of the respective surface measurement point lying in the imaging direction. Device comprising an optical distance sensor, in particular according to the chromatic or chromatic-confocal principle, comprising a plurality of mutually offset a workpiece surface detecting measuring beams, each measuring beam is assigned to determine a distance value between the sensor and a workpiece to be measured a separate measuring channel, each Measuring channel is associated with an optical fiber, and each fiber is assigned to a part of an evaluation, in particular each line of a matrix-shaped camera, wherein at least some of the measuring beams are arranged offset to each other on a first line perpendicular to the measuring direction of the measuring beams to each other, characterized in that a plurality of parallel Lines of measuring beams are arranged so that the lines are offset from each other in the direction perpendicular to the line direction to each other, and in addition have an offset in the line direction to each other, which is less than the distance of Me is in the line direction. Device comprising an optical distance sensor, in particular according to the chromatic or chromatic-confocal principle, comprising a plurality of mutually offset a workpiece surface detecting measuring beams, each measuring beam is assigned to determine a distance value between the sensor and a workpiece to be measured a separate measuring channel, each An optical fiber is assigned to the measuring channel, and each fiber is assigned to a part of an evaluation unit, in particular each row of a matrix-shaped camera, wherein at least some of the measuring beams are offset on a first line perpendicular to the measuring direction of the measuring beams, characterized in that at least one twisted second line to the measuring direction, in particular rotated by 90 °, is arranged to the first line, wherein preferably the mutually rotated measuring lines are arranged in each case shifted in the line direction and / or the Installation angle of the sensor is selected to the measuring direction so that with respect to a predetermined perpendicular to the measuring direction extending preferred scanning direction or direction of a generated by all the measuring beam lateral resolution is achieved, which is greater than the caused by the distance of the measuring beams on each line lateral Resolution. Method for operating the device according to Claim 11 or 12 , characterized in that to increase the resolution in the lateral direction, ie the direction perpendicular to the measuring direction and perpendicular to a predetermined preferred scanning direction, the measuring beams of the offset and / or twisted lines arranged on the several lines are used for a common evaluation. A method for recording, display and evaluation of an image, preferably used in a measuring microscope or optical coordinate measuring machine with image processing sensor, wherein at least one image is taken with a camera, an image on an output means, such as screen, is displayed to the operator and the operator on the basis of Representation selects the areas where measurement points are to be determined, and wherein the evaluation comprises at least the determination of one or more measurement points on one or more detected by at least one image edges of a workpiece by means of an edge detection method, the evaluation preferably the dimensional linkage of multiple measurement points Includes measures, characterized in that from a plurality of images recorded with the camera, a high dynamic range image (HDR image) is generated, which is used for the display on the display means and / or ver for the determination of the measuring points ver is used.

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