Device and method for detecting a characteristic of a measurement

Abstract

The invention relates to a device for measuring properties of a measurement object (9), comprising a measuring device (1) having at least one positioning unit (4) and at least one measuring unit (3), the positioning unit (4) positioning the measurement object (9) and the measuring unit (3) relative to one another, a calculation module (16), and an evaluation unit (2) having an evaluation module (17), an image of the measurement object (9) can be generated from the position data and the measurement data by means of the calculation module (16), characterized in that a standardization interface (19) for transmitting data is formed between the calculation module (16) and the evaluation module (17), the transmitted data is not only the data of the measuring unit (3) but also the data of the positioning unit (4). The invention further relates to a method for detecting a property of a measurement object by means of a measurement technique.

Description

Technical Field

[0001] The invention relates to a device for detecting properties of a measurement object using measurement technology, comprising a measuring device having at least one positioning unit and at least one measuring unit, a computing module and an evaluation module, wherein the positioning unit positions the measurement object and the measuring unit relative to each other and the measuring unit detects measurement values ​​or measurement data of the measurement object, wherein an image of the measurement object can be generated from the position data and the measurement data by the computing module.

[0002] Furthermore, the invention relates to a method for measuring a property of a measurement object using metrology. Background Art

[0003] Devices and methods for optical measurement of measuring objects are used for a variety of applications in industry, research and development. Such measuring devices are usually composed of a positioning unit, a measuring unit and an evaluation unit. The positioning unit is used to move the measuring object relative to the measuring unit to a measuring position or to position the measuring unit relative to the measuring object. The measuring unit detects the characteristics of the measuring object with the help of a measuring system, which works according to the physical measurement principle matched to the characteristics to be checked of the measuring object. The evaluation unit controls the positioning unit and detects the measured value of the measuring unit. The control signal of the positioning unit is transmitted via an interface, and the measured value or measurement data of the sensor unit is also transmitted via the interface. Due to the higher flexibility, digital interfaces are mainly used today. Here, a distinction is made between (physical) hardware interfaces and software protocols running on them. Different layers are defined for digital interfaces, wherein the bottom layer usually forms a (physical) hardware interface. Above this bottom layer, there are software protocols that are built one on top of the other, starting from the transport layer to the top layer of the application layer (for example, according to the ISO / OSI reference model or the TCP / IP reference model). In the evaluation unit, the data transmitted thereby is further processed and visualized or forwarded to a higher-level controller for further use.

[0004] The ISO / OSI layer model was developed already in the 1970s to reflect the gradual development in the field of interfaces and networks between computers. Layer 1 (Physical Layer) represents the physical connection. Simple serial interfaces such as RS-232 or RS-422 are shown, which are still in use today. Layer 2 (Data Link Layer) already provides error handling and data flow control, known protocols are SDLC, HDLC or Ethernet. Layer 3 (Network Layer) describes the switching of connections or the forwarding of data packets with the help of the best-known protocol IP (Internet Protocol), which is the basis of the Internet. Layer 4 (Transport Layer) is responsible for the end-to-end control of the data flow, known protocols are UDP (User Datagram Protocol) or TCP (Transmission Control Protocol).

[0005] Layers 1 to 4 describe the standardization of the network-related layers used, i.e. the manner and method of "how" data is transmitted between the measuring units, positioning units and evaluation units. The meaning of the data transmitted is application-specific and manufacturer-specific. Above these layers are the application-related layers, i.e. layers 5 to 7, which define the structure and meaning of the data, i.e. "what" is to be transmitted. There are protocols that work with the application programs.

[0006] The TCP / IP reference model provides a further representation of a layer model with four layers built one on top of the other. The first three layers correspond essentially to layers 1 to 4 of the ISO / OSI model. Above this, the application layer is provided as the last layer.

[0007] Digital interfaces for industrial applications usually contain freely definable areas, whereby the user can predefine specific parameters suitable for the respective application, for example for measuring units such as sensors or cameras or positioning units such as linear axes or robots. These parameters are used to parameterize the respective associated units. The interfaces are usually assigned to the higher layers of the reference model, since it is there that "what" (e.g. application-specific or user-specific parameters) is determined to be transmitted.

[0008] Industrial interfaces such as Profibus, Interbus or EtherCAT are usually used to control the positioning unit. This allows specific parameters for positioning to be set, such as starting position, acceleration and deceleration ramps, feed speed, etc.

[0009] For all types of measurement systems, there are standardized interfaces that conform to a predetermined standard transmission protocol. Examples of such interfaces include I 2 C, IO-Link or CAN bus. Interfaces such as GigE Vision or CameraLink have become the established interfaces for optical measuring devices, especially cameras. With the help of freely definable areas, certain camera parameters such as exposure time, resolution, frame rate, etc. can be set to adapt the camera to the respective measuring task.

[0010] Measuring devices known from the prior art use separate interfaces, such as GigE Vision for cameras and EtherCAT for positioning units, for controlling or regulating the control of the positioning unit and for transmitting the measured values ​​of the measuring unit. In the above-mentioned evaluation units, the interfaces are usually addressed by dedicated application software to establish communication between the measuring or positioning unit and the evaluation unit. Therefore, the application software must operate two interfaces, namely the interface of the positioning unit and the interface of the measuring unit. Dedicated means that the manufacturer of the measuring device has created his own application software, which can exchange and process data with the measuring unit and the positioning unit and provide the data to the user in a suitable form. Here, two interfaces must be programmed, namely one for the positioning unit and the other for the measuring unit.

[0011] Instead of using the manufacturer's own application software, commercially available application software is also used. Even then, programming work is required to create a dedicated interface and the commercially available application software also needs to be adapted.

[0012] The disadvantage of such a dedicated solution is therefore the high programming effort, since individual adjustments have to be made depending on the type of measuring device. In addition, the dedicated solution is decoupled from the further development of the standard. Summary of the invention

[0013] It is therefore an object of the present invention to design and improve a device and a method of the type mentioned at the outset in such a way that the detection of properties of a measured object is possible with a low programming effort.

[0014] According to the invention, the aforementioned object with respect to the device is achieved by the features of claim 1. The device is therefore used for measuring properties of a measuring object by metrology, comprising a measuring device with at least one positioning unit and at least one measuring unit, a computing module and an evaluation module, wherein the positioning unit positions the measuring object and the measuring unit relative to one another, and the measuring unit detects measurement data of the measuring object, wherein an image of the measuring object can be generated by the computing module from the position data and the measurement data, characterized in that a standardized interface for transmitting data is formed between the computing module and the evaluation module, and the transmitted data are both data of the measuring unit and data of the positioning unit.

[0015] With regard to the method, the aforementioned object is achieved by the features of the auxiliary claim 9. A method is thus provided for measuring properties of a measurement object by metrological means, in particular by means of a device according to any one of claims 1 to 8, the device comprising a measuring device with at least one positioning unit and at least one measuring unit, a computing module and an evaluation module, wherein the measurement object and the measuring unit are positioned relative to one another by the positioning unit and measurement data of the measurement object are detected by the measuring unit, wherein an image of the measurement object is generated by the computing module from the position data and the measurement data, wherein both the data of the measuring unit and the data of the positioning unit are transmitted via a standardized interface between the computing module and the evaluation module.

[0016] In the manner according to the invention, it has been recognized that, in addition to the measurement unit data initially predetermined via a standardized interface, data for a positioning unit can also be transmitted via the same interface in addition, or vice versa. For this purpose, for example, a freely definable area of ​​the interface or a freely definable area in the interface protocol can be used to transmit data for the positioning unit. The freely definable area can exist, for example, as a definition block in a data stream, or as an addressable storage area, or as a data area in a configuration file (e.g., an xml file). The advantage is that standardized interfaces can be used and special software does not have to be generated. It is also advantageous that standardized or commercially available standard software can be used for further processing of the data (measurement data and position data) as long as the standard software supports such a standardized interface.

[0017] In other words, the use of standardized interfaces has the advantage that no dedicated software has to be programmed in the evaluation unit, but commercially available evaluation software compatible with standards (eg GenICam), such as Halcon, can be used as an evaluation module. Alternatively, commercially available evaluation units compatible with standards can also be used.

[0018] The solution according to the present invention may have the following features:

[0019] - Positioning the measured object relative to the measuring unit or vice versa by means of the positioning unit in one, two or three spatial axes and angles (including rotation, for example a 6-axis robot), wherein position data of the measured object and / or position data of the positioning unit are determined.

[0020] - A property of the measurement object is detected by means of the measuring unit, wherein measured values ​​or measurement data are generated.

[0021] - A consistent data set containing position data and measurement data is generated in the calculation module.

[0022] - Output of data sets via digital interfaces.

[0023] -Control the measuring equipment via the same interface.

[0024] The interface is standardized but can have specific, freely definable or programmable areas.

[0025] The specific area can contain both data for the positioning unit and data for the measuring unit.

[0026] An exemplary embodiment of the measuring device may have:

[0027] Positioning units, such as linear axes, xy tables, manipulators, robots, etc., by means of which an object can be brought into a possibly predeterminable position in space relative to another object.

[0028] - Measuring units, such as measuring instruments, sensors, cameras, scanners, are used to detect geometric properties (such as distance, position, contour, geometry, etc.), optical properties (such as color, gloss, texture, etc.) or other properties (such as magnetic properties, roughness, etc.) of the measurement object or its surface.

[0029] The control unit can be a computer (e.g. an industrial computer, a microcontroller, an SPS) which, on the one hand, specifies control instructions for a control module of the positioning unit and, on the other hand, calculates the position data of the positioning unit with the measured values ​​or measurement data of the measuring unit into a consistent data set and thereby generates an image of the measured object.

[0030] The interface can advantageously be a digital interface with a standardized protocol (eg GenICam for image processing) which connects the computing module to the evaluation module.

[0031] At this point it should be pointed out that within the scope of the present disclosure the term “GenICam” is to be understood as a generic programming interface for cameras (“Generic Interface for Cameras”) maintained by the European Machine Vision Association (EMVA).

[0032] The use of GenICam offers the possibility of reflecting additional parameters in addition to the settings defined in the standard. The structure for embedding additional parameters is predetermined by the standard. GenICam stipulates that the server (in this case the computing module) describes its behavior via an xml file (so-called GenICam.xml). This file contains, for example, the following freely definable areas:

[0033] -Required parameters that must be given to each GenICam server

[0034] ○Version number

[0035] ○Device Name

[0036] -Optional standard parameters that can be given by the GenICam server

[0037] ○ Field of view

[0038] ○Exposure time

[0039] ○ Resolution

[0040] GenICam offers the possibility to transmit, in addition to the above-mentioned camera-specific parameters, additional user-defined parameters that can be used to control the positioning unit via the same interface. For this purpose, user-defined functions, so-called Features, can be freely defined in GenICam.xml according to the Standard Function Naming Convention (SFNC). For the control of the positioning unit, these parameters can be, for example,

[0041] ○Measurement speed of the measurement unit

[0042] ○Positioning speed

[0043] ○Axis limit

[0044] ○Acceleration slope

[0045] Depending on the standard, functions can be grouped into a number of categories. It is expedient to create a category for parameters for positioning devices, for example.

[0046] According to the invention, it has been recognized that in the GemICam standard, which is actually provided for camera control, additional functions can be defined which can also transmit non-camera-specific parameters (in this case, specific parameters of the positioning unit). This makes it possible to use a standardized interface (GenICam) without additional programming effort to control both the measuring unit and the positioning unit.

[0047] The measuring unit can advantageously detect one-dimensional (point sensor), two-dimensional (line scanner) or three-dimensional (camera) measured values ​​or measurement data. Furthermore, by moving the measuring unit or the measured object (along a predetermined trajectory) with the aid of the positioning unit (only relative movement is required), a multidimensional image of the measured object can be achieved. The measured values ​​can be detected as a function of the (relative or absolute) position and a 2D or 3D data set can be generated, which corresponds to an image or a point cloud (both are referred to as "images" within the framework of the present disclosure).

[0048] The term “image” within the scope of the present disclosure may be understood in a general sense to mean that an image may also include, in particular, measured values ​​which do not represent an image in the true sense but rather a spatial arrangement of measured values, such as a temperature distribution, a color distribution, etc.

[0049] For example, with the aid of a point-measuring distance sensor (eg a laser triangulation sensor), an image or a surface profile of a surface can be generated by scanning the surface in two axes (x-axis and y-axis).

[0050] Further examples of measuring units and images that can be generated thereby may be:

[0051] - determination of the distribution of the surface temperature of the measurement object by means of a temperature sensor,

[0052] - determining the geometry and / or the roughness of the surface of the measurement object by means of a confocal sensor,

[0053] - determining the color gradient of the surface of the measurement object by means of a color sensor,

[0054] - an image of the surface of the measuring object is generated by a line scanner moving in one axis,

[0055] - directly generate an image of the surface of the measurement object by means of a camera,

[0056] - Determine the thickness of the measurement object by means of one or more path or position sensors.

[0057] For larger measurement objects, individual images may need to be stitched together and combined (stitching) by scanning if necessary.

[0058] The position of the measured object in space relative to the measuring unit is known in the device according to the invention and the method according to the invention, since the positioning unit contains an integrated position measurement or the position is determined by means of an external sensor. A high absolute accuracy of the positioning unit is not necessarily required. It is also conceivable that the image is generated without position measurement, for example, when the positioning unit moves uniformly, i.e. at the same speed. In this case, it is sufficient to know the starting point. The starting point can also be a feature of the measured object (e.g. an edge), which, when detected, generates a trigger signal by means of the measuring unit.

[0059] It is essential that the image of the measured object thus generated is transmitted to a higher-level evaluation unit for further processing via a standardized interface known, for example, from image processing. An integral part of the evaluation unit is an evaluation module, which performs the evaluation operation desired by the user on the image of the measured object. This can be, for example, an evaluation of certain geometrical properties of the measured object, such as form deviations, dimensional accuracy or size.

[0060] The positioning unit can have a control module in an advantageous manner, so as to be controlled by the control module. It can be considered here that the control signal for the drive device (motor, linear drive) is calculated in the calculation module by the parameters transmitted by the freely definable area of ​​the interface. It is particularly advantageous that, in addition to the parameters for control, position data is also transmitted. If the evaluation module supports the standard of the standardized interface, such as the GenICam standard, the subsequent evaluation module can (bidirectionally) read and process the data. Thus, for example, the measurement data can be assigned to the position data and the image of the measurement object can be generated in the control module. The image can then be transmitted to the evaluation unit through the standardized interface to be further evaluated at the evaluation module. Completely similarly, the freely definable area of ​​the interface for the positioning unit can also be used for the parameterization of the measuring unit.

[0061] The measuring device can have a control unit for controlling the positioning unit in a particularly advantageous manner. The computing module can be arranged in the control unit. Then the pre-processing of data can already be carried out in the computing module of the measuring device. In addition, modeling can already be carried out in the control unit. This means that the modeling of the measuring device can already be carried out in the control unit by the manufacturer. From the outside, the behavior of the measuring device is like a unit with device-specific characteristics compatible with the standard. The standardized interface to the evaluation unit then provides the possibility of using a commercially available evaluation unit. This can be, for example, any computer that a user already has or obtains, on which a standard evaluation software (as Halcon already described) is run as an evaluation module. In the example of GenICam, the measuring device itself is thus used as a GenICam server, which transmits standard-compatible data (images) to any, standard-compatible evaluation software or evaluation unit.

[0062] It is worth noting that the device according to the invention has features that can include method features. Said features and the advantages achieved thereby can be explicitly part of the method according to the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] There are now various possibilities for designing and improving the solution of the invention in an advantageous manner. For this purpose, reference is made on the one hand to the dependent claims of claims 1 and 9 and on the other hand to the following description of preferred embodiments of the invention with the aid of the drawings. In conjunction with the description of preferred embodiments of the invention with the aid of the drawings, preferred embodiments and further embodiments of the solution are generally also explained. In the drawings:

[0064] Figure 1 An embodiment of a measuring device is shown schematically.

[0065] Figure 2 The schematic diagram shows Figure 1 An embodiment comprising a functional unit according to the prior art,

[0066] Figure 3 The schematic diagram shows Figure 1 An embodiment comprising a functional unit according to the invention,

[0067] Figure 4 A schematic diagram shows a further exemplary embodiment of a functional unit according to the invention. Figure 1 An embodiment of the invention, and

[0068] Figure 5 The structure of the xml file in the GenICam standard is shown schematically. DETAILED DESCRIPTION

[0069] Figure 1A device for detecting properties of a measurement object 9 by measuring technology is shown. The device has a measuring device 1 and an evaluation unit 2. The measuring device 1 comprises a measuring unit 3 and a positioning unit 4 in the form of an xy table, in which a first linear slide 5 can be moved in an x ​​direction 6 (indicated by a double arrow) and a second slide 7 can be moved in a y direction 8 (indicated by a double arrow). As a result, the measurement object 9 can be positioned relative to the measuring unit 3 on two axes x, y. The measuring unit 3 is placed above the xy table by a suitable holding device 10. If the measuring unit 3 is, for example, a laser triangulation sensor with point measurement evaluation, the measurement object 9 can be scanned and the surface of the measurement object can be measured. In the example, this is a metal cylinder with a hole in the middle. The measuring device 1 is controlled by the evaluation unit 2, which is connected to a first interface 11 for the measuring unit 2 and a second interface 12 for the positioning unit 4 together with the measuring device 1 (the interfaces 11, 12 are only shown schematically).

[0070] Figure 2 The schematic diagram shows the Figure 1 Device, which includes functional units according to the prior art. In the prior art, the interface between the measuring device 1 and the evaluation unit 2 consists of two separate interfaces 11, 12. The interface 11 connects the measuring unit 3 to the evaluation unit 2, and the other interface 12 connects the xy table 4 to the evaluation unit 2. Usually, the interfaces commonly used in measurement technology are used for the first interface 11. For the measuring unit 3, which represents image processing in the broadest sense, the first interface is, for example, GenICam. The second interface 12 is an interface commonly used, for example, in automation technology to control the axes of the xy table, and the second interface is, for example, ProfiBus. In order to control the linear axes, the positioning unit 4 includes a control module 13. The measuring object 9 is guided by means of the positioning unit 4 (symbolically indicated by line 14) and positioned relative to the measuring unit 3. The measuring unit 3 detects the measured values ​​or measurement data of the measuring object 9 (symbolically indicated by arrow 15), which are calculated in the calculation module 16 together with the position data from the positioning unit 4 to generate an image of the measuring object. The image is generated in the output Figure 1 In the example of , the geometric structure of a metal cylinder is in the form of a 3D data set. The calculation module 16 is a component of the evaluation unit 2. In addition, the evaluation unit 2 contains an evaluation module 17. The evaluation module 17 is connected to the calculation module 16 via a dedicated interface 18.

[0071] Figure 3 Shown from Figure 2Instead of the dedicated interface 18, a standardized interface 19 is used, which transmits both data for the measuring unit 3 and data for the positioning unit 4 between the calculation module 16 and the evaluation module 17. By using the standardized interface 19, it is possible to use evaluation software compatible with the standard as the evaluation module 17.

[0072] Figure 4 A further embodiment according to the invention is shown with a measuring device 1, which comprises a control unit 20 with a computing module 16. The preprocessing of the data of the measuring unit (measured values, parameters) and the positioning unit (position data, parameters) takes place in the computing module 16 of the control unit 20. A standardized interface 19 serves as an interface between the control unit 20 and the evaluation unit 2. The control unit 20 here controls the linear axes 5, 7 (not shown in the drawing), which position the measured object 9 relative to the measuring unit 3. At the same time, the control unit 20 receives the measurement data from the measuring unit 3 and combines them with the position data in the computing module 16 in order to generate an image of the measured object. The image is then transmitted via the standardized interface 19 to the evaluation unit 2, where it is further processed and evaluated in the evaluation module 17.

[0073] Figure 5 Finally, the structure of an XML file 21 according to the GenICam standard is shown in a very schematic diagram. Functions 22 are defined in the XML file 21, which define user-specific or application-specific parameters. In this case, the functions 1, 2, 3 of the positioning unit are grouped into a class 23.

[0074] With regard to further advantageous embodiments of the solution according to the invention, reference is made to the general part of the description and to the appended claims in order to avoid repetitions.

[0075] Finally, it should be explicitly pointed out that the above-described embodiments of the solution according to the invention are only used to discuss the solution claimed for protection, but are not limited to the described embodiments.

[0076] List of Reference Numerals

[0077] 1. Measuring device

[0078] 2 Evaluation Units

[0079] 3 Measurement unit

[0080] 4 Positioning unit

[0081] 5 Linear slide

[0082] 6 x direction

[0083] 7 Linear slide

[0084] 8 y direction

[0085] 9 Measurement Objects

[0086] 10. Holding device

[0087] 11 Interface (measuring unit - evaluation unit)

[0088] 12 Interface (positioning unit - evaluation unit)

[0089] 13 Control Module

[0090] 14 Guide (measurement object)

[0091] 15 Measurement data

[0092] 16 Computing Module

[0093] 17 Evaluation Module

[0094] 18 Dedicated interfaces

[0095] 19 Standardized interfaces

[0096] 20 Control unit

[0097] 21.xml file

[0098] 22 Features

[0099] 23 categories.

Claims

1. A device for detecting properties of a measurement object (9) by measurement technology, comprising a measuring device (1) having at least one positioning unit (4) and at least one measuring unit (3), a calculation module (16) and an evaluation unit (2) having an evaluation module (17), wherein: The positioning unit (4) positions the measured object (9) and the measuring unit (3) relative to one another, and the measuring unit (3) detects measurement data of the measured object (9), wherein an image of the measured object (9) can be generated from the position data and the measurement data by the computing module (16). It is characterized in that a standardized interface (19) for transmitting data is formed between the calculation module (16) and the evaluation module (17), and the transmitted data are both data of the measuring unit (3) and data of the positioning unit (4).

2. The device according to claim 1, characterized in that The transmitted data are measurement data, position data, correction values, model data, control commands, diagnostic information, status information and / or parameters.

3. The device according to claim 1 or 2, characterized in that: The image is a combination of position data and measurement data, in particular a geometry or a surface or a temperature distribution or a color distribution.

4. The device according to any one of claims 1 to 3, characterized in that The standardized interface (19) has a freely definable and / or programmable area, wherein the area is used to transmit data.

5. The device according to any one of claims 1 to 4, characterized in that The standardized interface (19) is GenICam.

6. The device according to any one of claims 1 to 5, characterized in that The calculation module (16) is assigned as a component of the evaluation unit (2) or as a component of the measuring device (1).

7. The device according to any one of claims 1 to 6, characterized in that The measuring unit (3) has sensors, cameras, scanners for detecting geometrical properties, in particular spacing, position, thickness, contour and / or geometric structure, scanners for detecting optical properties, in particular color, gloss and / or texture, and / or scanners for detecting other properties, in particular magnetic properties and / or roughness.

8. The device according to any one of claims 1 to 7, characterized in that The positioning unit (4) has a linear axis and / or an xy table and / or a manipulator and / or a robot.

9. A method for measuring properties of a measurement object (9) by measurement technology, in particular by means of a device according to any one of claims 1 to 8, comprising a measuring device (1) having at least one positioning unit (4) and at least one measuring unit (3), a calculation module (16) and an evaluation module (17), wherein: The measuring object (9) and the measuring unit (3) are positioned relative to one another by the positioning unit (4) and the measuring unit (3) detects measurement data of the measuring object (9), wherein an image of the measuring object (9) is generated from the position data and the measurement data by the computing module (16), wherein both the data of the measuring unit (3) and the data of the positioning unit (4) are transmitted via a standardized interface (19) between the computing module (16) and the evaluation module (17).

10. The method according to claim 9, characterized in that The standardized interface (19) has a freely definable and / or programmable area, wherein the area is used to transmit data.

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