Apparatus and method for measuringly obtaining characteristics of an object to be measured

Abstract

A device for measuring the characteristics of a measurement object (9) by measurement, comprising a measurement device (1) having a positioning unit (4) and a measurement unit (3), a calculation module (16), and an evaluation unit (2) having an evaluation module (17), wherein the positioning unit (4) positions the measurement object (9) and the measurement unit (3) relative to each other, the measurement unit (3) detects measurement data of the measurement object (9), an image of the measurement object (9) can be generated by the calculation module (16) from the position data and the measurement data, a standardized interface (19) for transmitting data is formed between the calculation module (16) and the evaluation module (17), and the data to be transmitted is both the data of the measurement unit (3) and the data of the positioning unit (4). A method for measuring the characteristics of a measurement object is also specified.

Description

Technical Field

[0001] The present invention relates to an apparatus for measuring the characteristics of a measurement object in a metrological manner, comprising a measuring device having at least one positioning unit and at least one measuring unit, a calculation module, and an evaluation unit having an evaluation module, wherein the positioning unit positions the measurement object and the measuring unit relative to each other, the measuring unit acquires measurement data from the measurement object, and a representation of the measurement object can be generated by the calculation module from position data and measurement data.

[0002] Furthermore, the present invention relates to a method for acquiring the characteristics of a measurement object in a metrological manner.

Background Art

[0003] Devices and methods for optically measuring a measurement object are used in many applications in industry, research, and development. Such measuring devices typically consist of a positioning unit, a measuring unit, and an evaluation unit. The positioning unit is used to move the measurement object to a measurement position relative to the measuring unit or to position the measuring unit relative to the measurement object. The measuring unit acquires the characteristics of the measurement object using a measurement system. The measurement system operates according to a physical measurement principle adapted thereto according to the characteristic to be detected in the measurement object. The evaluation unit controls the positioning unit and acquires the measured values of the measuring unit. The control signal of the positioning unit is transmitted via an interface, like the measured values or measurement data from the sensor unit. Today, digital interfaces are mainly used because of their relatively high flexibility. In this case, it is divided into a (physical) hardware interface and a software protocol operating thereon. Digital interfaces usually have various layers defined, with the bottom layer forming the (physical) hardware interface. Above the bottom layer, there are various software protocol layers that are built on top of each other, from the transport layer to the topmost application layer (e.g., according to the ISO / OSI reference model or the TCP / IP reference model). In the evaluation unit, the data transmitted through the interface as described above is further processed, either visualized or transferred for further use by a higher-level control device.

[0004] The ISO / OSI layer model is a development from the 1970s that advanced the field of computer interfaces and networks. Layer 1 (Physical Layer) represents the physical connection. Simple serial interfaces such as RS232 and RS422, which are still in use today, are also shown in this layer. Layer 2 (Data Link Layer) provides error handling and data flow control, and protocols such as SDLC, HDLC, or Ethernet are known as protocols in this layer. Layer 3 (Network Layer) uses the most well-known protocol IP (Internet Protocol) that forms the basis of the Internet and represents connection switching or data packet transfer. Layer 4 (Transport Layer) regulates the control of data traffic from terminal to terminal, and protocols such as UDP (User Datagram Protocol) or TCP (Transmission Control Protocol) are known as protocols in this layer.

[0005] Layers 1 to 4 represent the standards of the network-related layers in use, that is, they represent "how" data is transmitted between measurement units, positioning units, and evaluation units. The data structure of the data to be transmitted is unique and manufacturer-specific. Above these layers, there are layers 5 to 7, which are application-related layers and define the structure and meaning of data, that is, what to transmit. Here, there is a protocol that interacts with the application program.

[0006] Another representation of the layer model is provided by the TCP / IP reference model, which has four overlapping layers. The first three layers mainly correspond to layers 1 to 4 of the ISO / OSI model. The application layer is located at the top as the final layer.

[0007] Industrial digital interfaces usually include freely definable areas where users can specify specific parameters suitable for each application, such as measurement units like sensors and cameras, and positioning units like linear axes and robots. These areas are used to parameterize the relevant units respectively. Such digital interfaces usually need to be assigned to the upper layers of the reference model. This is because what to transmit is defined there (in this example, it is application-specific or user-specific parameters).

[0008] Industrial interfaces such as Profibus, Interbus, and EtherCAT are often used to operate positioning units. This enables the setting of specific positioning parameters such as the starting position, speed gradient during acceleration and deceleration, and feed.

[0009] There are standardized interfaces with transmission protocols that follow specified standards in all types of measurement systems. Examples of such interfaces include I2C, IO-Link, or CAN bus. For optical measurement means, especially for cameras, interfaces such as GigEVision and CameraLink have been established, for example. In order to adapt the cameras to their respective measurement tasks, specific camera parameters such as exposure time, resolution, frame rate, etc. can be set using freely definable areas.

[0010] Conventionally known measuring devices use separate interfaces, such as GigEVision for cameras and EtherCAT for positioning units, to operate or control the positioning unit and transmit measurement values from the measurement unit. In the upper evaluation unit, the interface is frequently addressed via its own application software to establish communication between the measurement unit or positioning unit and the evaluation unit. Therefore, this application software needs to use two interfaces, namely the interface for the positioning unit and the interface for the measurement unit. By "own" it means that the manufacturer of the measuring device creates its own application software that can exchange data with the measurement unit and the positioning unit, process that data, and provide it to the user in an appropriate format. In this case, it is necessary to program two interfaces, specifically the interface for the positioning unit and the second interface for the measurement unit.

[0011] Instead of its own application software, commercially available application software is also used. In that case, programming costs for creating its own interface may be required, and programming costs for adapting commercially available application software may also be required in some cases.

[0012] Therefore, the disadvantage of such a unique solution is that programming costs are high because individual adjustments are required according to the model of the measuring device. Furthermore, the unique solution is separated from the standard development.

Summary of the Invention

Problems to be Solved by the Invention

[0013] Therefore, an object of the present invention is to design and develop the types of devices and methods mentioned at the beginning so that the characteristics of the object to be measured can be obtained while keeping the programming cost low.

Means for Solving the Problems

[0014] According to the present invention, the above object regarding the device is achieved by the features of claim 1. Therefore, the device of the subject matter is a device for obtaining the characteristics of an object to be measured in a metrological manner, comprising a measuring device having at least one positioning unit and at least one measuring unit, a calculation module, and an evaluation module, wherein the positioning unit positions the object to be measured and the measuring unit relative to each other, the measuring unit acquires measurement data from the object to be measured, the representation of the object to be measured can be generated by the calculation module from the position data and the measurement data, a standardized interface for transmitting data is formed between the calculation module and the evaluation module, and the data to be transmitted is both data from the measuring unit and data from the positioning unit.

[0015] Regarding the method, the above object is achieved by the features of alternative independent claim 9. Claim 9 particularly relates to a method for obtaining the characteristics of a measurement object in a metrological manner, comprising an apparatus according to any one of claims 1 to 8, a measuring device having at least one positioning unit and at least one measuring unit, a calculation module, and an evaluation module, wherein the measurement object and the measuring unit are positioned relative to each other by the positioning unit, measurement data from the measurement object is acquired by the measuring unit, a representation of the measurement object is generated by the calculation module from the position data and the measurement data, and both data from the measuring unit and data from the positioning unit are transmitted between the calculation module and the evaluation module via a standardized interface.

[0016] According to the present invention, it is recognized that it is also possible to transmit data for the positioning unit using the same interface, in addition to data from the measuring unit initially specified by the standardized interface, or vice versa. For this purpose, it is possible to transmit data for the positioning unit, for example, using a freely definable area of the interface or a freely definable area within the protocol of the interface. This freely definable area may be in the form of, for example, a block defined within a data stream, an addressable memory area, or a data area within a configuration file (such as an XML file). The advantage of this configuration is that a standardized interface can be used without the need to create proprietary software. Furthermore, as long as standard software supports this standardized interface, there is also the advantage that standardized software or commercially available standard software can be used for further processing of the data (measurement data and position data).

[0017] In other words, using a standardized interface has the advantage that there is no need to program the evaluation unit with its own software, and commercially available evaluation software (e.g., Halcon) that is compatible with a standard (e.g., GenICam) can be used as the evaluation module. Alternatively, a commercially available evaluation unit that is compatible with the standard can also be used in the same way.

[0018] The present invention includes the following features. The position data of the measurement object and / or the positioning unit is determined by a positioning unit that positions the measurement object with respect to the measurement unit, or vice versa, along one, two, or three spatial axes and angles (including rotation, e.g., a 6-axis robot). The characteristics of the measurement object are acquired using the measurement unit, thereby generating measurement values or measurement data. A consistent data set including the position data and the measurement data is generated by the calculation module. The data set is output via a digital interface. The measuring device is controlled via the same interface. This interface is standardized but can have specific, freely definable, or parameterizable areas. These specific areas can include both data for the positioning unit and data for the measurement unit.

[0019] The configuration of the measuring device may have the following. A positioning unit, such as a linear axis, an x-y table, a magic hand, a robot, or a similar device, that can place an object in space at a predefinable position as much as possible with respect to other objects. A measurement unit, such as a measuring device, a sensor, a camera, a scanner, for acquiring geometric characteristics (such as distance, position, contour, shape, etc.), optical characteristics (such as color, gloss, texture, etc.), or other characteristics (such as magnetic characteristics, roughness, etc.) of the measurement object or its surface.

[0020] On the one hand, the control unit determines a control command for the control module of the positioning unit. On the other hand, it calculates the position data of the positioning unit using the measured values or measurement data from the measurement unit, forms a consistent data set, and generates a representation of the object to be measured. It may be a computer (such as an industrial PC, a microcontroller, a PLC, etc.).

[0021] It may be advantageous if the interface is a digital interface with a standardized protocol (such as GenICam for image processing) that connects the calculation module and the evaluation module.

[0022] In this case, the term "GenICam" is a general-purpose programming interface for cameras ("Generic interface for cameras") supported by the European Machine Vision Association (EMVA).

[0023] Using GenICam enables the generation of additional parameters in addition to the settings defined by the standard. In this case, the structure for embedding additional parameters is specified by the standard. GenICam enables the server (in this case, the calculation module) to describe its operation via an XML file (referred to as GenICam.xml). As an example, this file contains the following as freely definable areas. Required entries that each GenICam server needs to specify o Version number o Device specification Standard entries for options that the GenICam server can specify o Field of view o Exposure time o Resolution In GenICam, in addition to the above camera-specific parameters, additional user-defined parameters that can be used to operate the positioning unit can also be transmitted via the same interface. Therefore, user-defined functions can be freely defined in GenICam.xml according to the standard function naming convention (SFNC). When operating the positioning unit, for example, there are parameters such as the following. o Measurement speed of the measurement unit o Positioning speed o Axis limits o Speed gradient during acceleration

[0024] According to the standard, category functions can be combined. In that case, for example, it is convenient to form a category of parameters for the positioning unit.

[0025] Therefore, according to the present invention, it is recognized that additional functions that can be transmitted for criteria that are not specific to the camera (in this case, specific parameters of the positioning unit) can be defined in the GenICam standard actually provided for the operation of the camera. Therefore, both the measurement unit and the positioning unit can be controlled using the standardized interface (GenICam) without requiring additional programming costs.

[0026] It is advantageous that the measurement unit can acquire 1D (point sensor), 2D (line scanner) or 3D (camera) measurement values or measurement data. Furthermore, a multi-dimensional representation of the measurement object can be acquired (with only one relative movement) by a positioning unit that moves the measurement unit or the measurement object (along a specified trajectory). The measurement values can be acquired according to the (relative or absolute) position and can generate 2D or 3D data sets corresponding to an image or a point cloud (both are referred to as "representations" in the context of the present disclosure).

[0027] In the context of the present disclosure, the term "representation" is understood in a general sense. In particular, a representation does not necessarily represent an image in a strict sense, and may include, for example, measurements representing the spatial arrangement of measured values such as temperature distribution, color distribution, etc.

[0028] For example, by using a distance sensor that measures at each point (such as a laser triangulation sensor), it is possible to generate an image of the surface or the contour of the surface by scanning the surface in two axes (the x-axis and the y-axis).

[0029] Other examples of measurement units and representations that can be generated using them include the following. The distribution of the surface temperature of the object to be measured is determined by a temperature sensor. The shape and / or roughness of the surface of the object to be measured is determined by a confocal sensor. The color gradient of the surface of the object to be measured is determined by a color sensor. The representation of the surface of the object to be measured is generated by the one-axis movement of a line scanner. The representation of the surface of the object to be measured is directly generated by a camera. The thickness of the object to be measured is determined by one or more displacement sensors or position sensors.

[0030] When the object to be measured is relatively large, it may be necessary to stitch together individual images by scanning.

[0031] In the case of the device according to the present invention and the method according to the present invention, since the positioning unit incorporates a position measurement function or the position is determined using an external sensor, the spatial position of the object to be measured with respect to the measurement unit is known. The absolute accuracy of the positioning unit does not necessarily have to be high. For example, when the positioning unit moves uniformly, that is, moves at the same speed, it is also conceivable to generate a representation without position measurement. In this case, if the starting point is known, it is sufficient. The starting point may be a feature (e.g., an edge) of the object to be measured. When the measuring unit acquires the starting point, a trigger signal is generated.

[0032] It is important that the representation of the object to be measured thus generated is transferred to a higher-level evaluation unit for further processing via a standardized interface, such as is known in image processing. The components of the evaluation unit are an evaluation module that performs the evaluation operations desired by the user on the representation of the object to be measured. As an example, this evaluation operation may be an evaluation of specific geometric properties of the object to be measured, such as shape deviation, dimensional accuracy or dimensions.

[0033] It is advantageous if the positioning unit has a control module, and as a result, control is executed via the control module. In this case, the control signals for the drive device (motor, linear drive) are considered to be calculated from parameters transmitted via a freely definable area of the interface within the calculation module. It is particularly advantageous if, in addition to the operating parameters, position data is also transmitted. If the evaluation module supports the standards of a standardized interface, such as the GenICam standard, the downstream evaluation module can read and process these data (bidirectionally). For example, the measurement data can be pre-assigned to the position data of the control module, whereby a representation of the object to be measured can be generated. Subsequently, this representation can be transmitted to the evaluation module via the standardized interface to the evaluation unit for further evaluation. Similarly, the freely definable area of the interface for the positioning unit can also be used for the parameterization of the measuring unit.

[0034] It is particularly advantageous if the measuring device has a control unit for operating the positioning unit. The calculation module can be arranged within this control unit. In that case, the data can be pre-processed by the calculation module of the measuring device. Furthermore, the modeling may already be done within the control unit. That is, the modeling of the measuring device may be performed within the control unit by the manufacturer. In appearance, the measuring device operates like a unit that complies with standards and has device-specific characteristics. By using a standardized interface for the evaluation unit, it is possible to use commercially available evaluation units. This means, for example, that any computer already owned or acquired by the user can be used, and standard evaluation software (such as Halcon mentioned above) is executed as an evaluation module on that computer. Therefore, in the case of GenICam, the measuring device itself functions as a GenICam server and transmits data (representations) that comply with standards to any evaluation software or evaluation unit that complies with standards.

[0035] The device according to the present invention has the feature that it can take a form consistent with the method of the present invention. These features and the advantages achieved thereby may constitute the method according to the present invention.

[0036] There are various possibilities for advantageously configuring and developing the present invention. This can be achieved by first referring to the claims that depend on claim 1 and claim 9, and then referring to the following description of the embodiments of the present invention with reference to the drawings. In conjunction with the description of the embodiments of the present invention with reference to the drawings, general preferred configurations and developments will also be described.

Brief Description of the Drawings

[0037]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

[0038] FIG. 1 shows an apparatus for measuring the characteristics of a measurement object 9 in a metrological manner. The apparatus for measuring the characteristics of the measurement object 9 metrologically has a measuring device 1 and an evaluation unit 2. The measuring device 1 includes a measuring unit 3 and a positioning unit 4 in the form of an x-y table. In the positioning unit 4, a first linear slide 5 is movable in the x-direction 6 (indicated by double-headed arrows), and a second linear slide 7 is movable in the y-direction 8 (indicated by double-headed arrows). As a result, the measurement object 9 can be positioned with respect to the measuring unit 3 in each of the two axes x and y directions. Furthermore, the measuring unit 3 is attached above the x-y table via a suitable holder 10. When the measuring unit 3 is, for example, a laser triangulation sensor that measures and evaluates point by point, the surface of the measurement object 9 may be measured by scanning the measurement object 9. In this embodiment, the measurement object 9 is a metal cylinder having a hole in the central part. The measuring device 1 is controlled by the evaluation unit 2, and this evaluation unit 2 is connected to the measuring device 1 by a first interface 11 for the measuring unit 2 and a second interface 12 for the positioning unit 4 (only schematically shown for the first interface 11 and the second interface 12).

[0039] Figure 2 shows a schematic view of the apparatus of FIG. 1, including 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 first interfaces 11 and second interfaces 12. One interface 11 connects the measuring unit 3 to the evaluation unit 2, and the other second interface 12 connects the xy table 4 to the evaluation unit 2. Normally, a common interface in measurement technology is used for the first interface 11. As a measuring unit 3 representing image processing in the broadest sense, for example, GenICam can be mentioned. The second interface 12 is generally an interface used to operate the axes of the xy table in automation technology, for example, ProfiBus. The positioning unit 4 includes a control module 13 for operating the linear axis. The measurement object 9 is guided using the positioning unit 4 (as symbolically shown by line 14) and is positioned with respect to the measurement unit 3. The measurement unit 3 acquires measurement values or measurement data from the measurement object 9 (as symbolically shown by arrow 15), and in the calculation module 16, as a result of calculating these measurement values and measurement data using the position data from the positioning unit 4, a representation of the measurement object 9 is generated. In the embodiment of FIG. 1, this representation has the shape of a metal cylinder in the form of a 3D data set. In this case, the calculation module 16 is a component of the evaluation unit 2. The evaluation unit 2 further includes an evaluation module 17. The evaluation module 17 is connected to the calculation module 16 via a dedicated interface 18.

[0040] Figure 3 shows an embodiment of the apparatus of FIG. 2 according to the present invention. Instead of the individual interface 18, a standardized interface 19 is used that communicates both the data of the measuring unit 3 and the data of the positioning unit 4 between the calculation module 16 and the evaluation module 17. By using the standardized interface 19, evaluation software that is compatible with the standard can be used as the evaluation module 17.

[0041] Figure 4 shows a further embodiment of the invention, comprising a measuring device 1 including a control unit 20 having a calculation module 16. Data from the measuring unit 3 (measured values, parameters) and the positioning unit 4 (position data, parameters) are preprocessed in the calculation module 16 of the control unit 20. The standardized interface 19 is used as the interface between the control unit 20 and the evaluation unit 2. In this case, the control unit 20 operates the linear axes 5, 7 (not shown) that position the measurement object 9 relative to the measuring unit 3. At the same time, the control unit 20 receives measurement data from the measuring unit 3 and links the measurement data to the position data in the calculation module 16 to form a representation of the measurement object 9. Next, this representation is transmitted to the evaluation unit 2 via the standardized interface 19 and is further processed and evaluated in the evaluation module 17.

[0042] Finally, Figure 5 very schematically shows the structure of an XML file 21 according to the GenICam standard. A function 22 for defining user-specific or application-specific parameters is defined within the XML file 21. In this case, the functions 1, 2, 3 of the positioning unit are combined within the category 23.

[0043] For further embodiments of the invention, reference is made to the general part of the description and the appended claims in order to avoid repetition.

[0044] Finally, the embodiments of the present invention are for illustrative purposes only and are not limited to these exemplary embodiments.

Explanation of Reference Numerals

[0045] 1 ··· Measuring device 2 ··· Evaluation unit 3 ··· Measuring unit 4 ··· Positioning unit 5 ··· Linear slide 6 ··· x-direction 7 ··· Linear slide 8 ··· y-direction 9 ··· Object to be measured 10 ··· Holder 11 ··· Interface (Measuring unit - Evaluation unit) 12 ··· Interface (Positioning unit - Evaluation unit) 13 ··· Control module 14 ··· Guide mechanism (of the object to be measured) 15 ··· Measurement data 16 ··· Calculation module 17 ··· Evaluation module 18 ··· Proprietary interface 19 ··· Standardized interface 20 ··· Control unit 21 ··· XML file 22 ··· Function 23 ··· Category

Claims

1. A device for measuring the characteristics of a measurement object (9) by measurement, 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 measurement object (9) and the measuring unit (3) relative to each other, the measuring unit (3) acquires measurement data from the measurement object (9), the representation of the measurement object (9) can be generated by the calculation module (16) from the position data of the positioning unit (4) and the measurement data of the measuring unit (3), a standardized interface (19) for transmitting data is formed between the calculation module (16) and the evaluation module (17), and the data to be transmitted is both the measurement data from the measuring unit (3) and the position data from the positioning unit (4). A device for measuring the characteristics of a measurement object (9) by measurement.

2. The device according to claim 1, wherein the data to be transmitted is 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 claim 2, wherein the representation is a combination of position data and measurement data, in particular shape or surface or temperature distribution or color distribution.

4. The standardized interface (19) has a freely definable and / or parameterizable area, and the area is used for transmitting the data. The device according to any one of claims 1 to 3.

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 acquiring geometric properties, in particular distance, position, thickness, contour and / or shape, scanners for acquiring optical properties, in particular color, gloss and / or texture, and / or scanners for acquiring 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 x-y table and / or a magic hand and / or a robot.

9. A method for measuring the characteristics of a measurement object (9) in a metrological manner, 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), the device being according to any one of claims 1 to 8, wherein: the measurement object (9) and the measuring unit (3) are positioned relative to each other by the positioning unit (4); measurement data from the measurement object (9) are acquired by the measuring unit (3); a representation of the measurement object (9) is generated by the calculation module (16) from the position data and the measurement data; A method for measuring the characteristics of a measurement object (9) in which both the data from the measurement unit (3) and the data from the positioning unit (4) are transmitted between the calculation module (16) and the evaluation module (17) via a standardized interface (19).

10. The standardized interface (19) has an area that can be freely defined and / or parameterized, The method according to claim 9, characterized in that the area is used for the transmission of the data.

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