CN114531583A

CN114531583A - Method and device for checking the completeness of display content during the transmission of vehicle display information

Info

Publication number: CN114531583A
Application number: CN202111384658.3A
Authority: CN
Inventors: C·维施胡森; H·鲁斯; H·卡尔; J·曾克; V·沃尔默
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2020-11-23
Filing date: 2021-11-22
Publication date: 2022-05-24
Also published as: DE102020214694A1

Abstract

The solution presented herein relates to a method and apparatus for verifying the completeness of display content when transmitting vehicle display information. In the providing step, a desired display signal is provided via a transmission path. In the outputting step, image data of a desired display signal is output so that the image data is displayed on the display device as actual image content. In the step of transmitting, an image content signal representing actual image content is transmitted via the transmission path and provided to the image comparing device. In the step of comparing, the desired display signal is compared with the image content signal so as to evaluate the completeness of the display content as non-given when there is an identified difference between the image data of the desired display signal and the actual image content of the image content signal, and as given when there is no identified difference between the image data of the desired display signal and the actual image content of the image content signal.

Description

Method and device for checking the completeness of display content during the transmission of vehicle display information

Technical Field

The invention proceeds from a device or a method according to the preamble of the independent claims. A computer program is also the subject of the present invention.

Background

DE 102011116642 a1 describes a transmission device and a method for the safe transmission of a sensor signal to a transmission target and for the safe transmission of the sensor signal in a motor vehicle.

Disclosure of Invention

Against this background, with the solution presented here, a method for checking the completeness of display content when transmitting at least one display message for a vehicle is presented according to the independent claims, furthermore a device using this method is presented, and finally a corresponding computer program is presented. Advantageous embodiments and refinements of the device described in the independent claims are possible by the measures cited in the dependent claims.

An advantage achievable with the presented solution is that video and image transmission, for example via a video stream, is combined with the concept of a closed monitoring chain. The completeness of the display content can thus be checked particularly quickly and safely.

A method for checking the completeness of display content during the transmission of at least one piece of display information for a vehicle is described. The method comprises the steps of providing, outputting, transmitting and comparing. In the providing step, a desired display signal is provided via the transmission path, wherein the desired display signal represents image data of at least one safety information of the vehicle. In the step of outputting, image data of a desired display signal is output so as to be displayed on a display device as actual image content. In the step of transmitting, an image content signal representing actual image content is transmitted via a transmission path and provided to the image comparison device. In the step of comparing, the desired display signal is compared with the image content signal in order to evaluate the completeness of the display content as non-given (gegegeeben) if there is an identified difference between the image data of the desired display signal and the actual image content of the image content signal, and to evaluate the completeness of the display content as given if there is no identified difference between the image data of the desired display signal and the actual image content of the image content signal.

The vehicle may be a manually controllable vehicle or may be a vehicle that may be driven partially or highly automated. The display content may be content of information displayed or to be displayed for the driver of the vehicle. The transmission path may be a transmission medium such as ethernet, WLAN, or APIX (automatic Pixel Link). The transmission path may comprise a bidirectional data path or two unidirectional transmission paths. Due to the method presented here, the check can advantageously be carried out by transmitting data via the same transmission path in reverse for the comparison. In this way, if the completeness of the display content is assessed in the step of comparison as being unspecified, measures can be implemented, for example.

According to one embodiment, the image data of the actual image content can be compressed in the step of transmitting in order to provide the image content signal. In this way, compressed image data can be transmitted back, so that a fast data transmission can be achieved.

In the providing step, in the case of using the image compression unit, the data rate of the image data may be reduced. In this way, the image data provided for the display device can also already be compressed, so that a fast data transmission can be achieved.

According to one embodiment, in the step of outputting, the image data of the desired display signal can be decoded in order to generate the actual image content. This makes it possible, for example, to display previously encoded and additionally or alternatively compressed image data.

Furthermore, it is advantageous according to one embodiment that the following image content signals are transmitted in the step of transmitting: the image content signal represents a predefined component of the actual image content. For example, the predefined component may be a key component of the actual image content, which is defined, for example, by the relevant standard ISO26262 in one of the various security levels ASIL a to ASIL D for functional security. In this case, as a key component, for example, a gear display of the fully automatic transmission, a warning message of the engine control unit or a warning message of the driver assistance system can be mentioned. In such key components, correct display is important because the driver relies on the displayed content during driving. Transmitting back only such security-critical components for verification may reduce data flow and thus may reduce system utilization (systemuslatung). In the step of transmitting, non-security-critical (i.e. non-critical) components of the actual image content, such as e.g. time information, may e.g. not be transmitted back for verification.

The method may furthermore have the step of generating a backup level signal (rueckfalllebenensinal) if the completeness of the display content is assessed as unspecified in the step of comparing, wherein the backup level signal is designed to provide a display content predetermined as a backup level. Therefore, a measure for correction can be implemented. The backup level signal can be designed, for example, to suppress the display of the actual image content on the display device at least partially or completely. For example, the backup level signal may be configured to suppress the display of a predefined component of the actual image content on the display device, or to display an action instruction for the driver. This may be advantageous for safety while driving.

For example, the step of comparing may be performed using a predefined comparison rule for similarity comparison. Instead of, for example, comparing the same content, it is thus possible to use lossy and thus significantly more efficient compression methods.

The method can be implemented, for example, in software or hardware, or in a hybrid form of software and hardware, for example, in a control device.

Furthermore, the solution presented here proposes a device which is designed to carry out, manipulate or carry out the steps of a variant of the method presented here in a corresponding device. The object on which the invention is based is also achieved by the embodiment variant of the invention in the form of a device in a rapid and efficient manner.

To this end, the device may have: at least one computing unit for processing signals or data; at least one storage unit for storing signals or data; at least one interface to the sensor or the actuator for reading in sensor signals from the sensor or for outputting data or control data to the actuator; and/or at least one communication interface for reading in or outputting data, which elements are embedded in a communication protocol. The computing unit may be, for example, a signal memory, a microcontroller or the like, wherein the memory unit may be a flash memory, an EEPROM or a magnetic memory unit. The communication interface can be designed to read in or output data wirelessly and/or by wire, wherein the communication interface, which can read in or output wired data, can read in these data from the corresponding data transmission line, for example electrically or optically, or can output these data into the corresponding data transmission line.

A device is understood here to mean an electrical device which processes sensor signals and outputs control signals and/or data signals as a function of these sensor signals. The device may have an interface, which may be constructed in hardware and/or in software. In a hardware-based design, the interfaces can be parts of a so-called system ASIC that contain the very different functions of the device. However, it is also possible that the interface is an inherently integrated circuit or is at least partly formed by discrete components. In a software-based design, the interface can be a software module, which is present on the microcontroller, for example, next to another software module.

In an advantageous embodiment, the completeness of the display content is checked during the transmission of at least one piece of display information for the vehicle by means of the device. For this purpose, the device has actuators like supply means, output means, transmission means and image comparison means. The provision device is designed to provide a desired display signal via the transmission path, wherein the desired display signal represents image data of at least one safety information item of the vehicle. The output device is configured to output image data of a desired display signal to display the image data as actual image content on the display device. The transmission device is designed to transmit an image content signal representing the actual image content via the transmission path and to supply the image content signal to the image comparison device. The image comparison means is configured to compare the desired display signal with the image content signal in order to evaluate the completeness of the display content as non-given if there is an identified difference between the image data of the desired display signal and the actual image content of the image content signal, and to evaluate the completeness of the display content as given if there is no identified difference between the image data of the desired display signal and the actual image content of the image content signal.

A computer program product or a computer program with the following program code is also advantageous: the program code may be stored on a machine readable carrier or storage medium like a semiconductor memory, a hard disk memory or an optical memory; and in particular when the program product or the program is implemented on a computer or a device, to carry out, implement and/or handle the steps of the method according to one of the embodiments described above.

Drawings

Embodiments of the solution presented herein are illustrated in the drawings and are set forth in more detail in the description that follows.

Fig. 1 shows a schematic illustration of a vehicle with a device for checking the completeness of display content when transmitting at least one display information according to an embodiment;

FIG. 2 shows a schematic diagram of a display system according to an embodiment;

figures 3 to 4 each show a schematic view of an apparatus according to an embodiment;

fig. 5 to 6 each show a schematic view of a display apparatus having a device according to an embodiment; and

fig. 7 shows a flowchart of a method for checking the completeness of display content when transmitting at least one display information for a vehicle according to an embodiment.

In the following description of advantageous embodiments of the invention, identical or similar reference numerals are used for elements shown in different figures and functioning similarly, wherein repeated descriptions of these elements are omitted.

Detailed Description

Fig. 1 shows a schematic illustration of a vehicle 100 with a device 105 for checking the completeness of display content when transmitting at least one display message according to an embodiment.

Merely by way of example, the device 105 is accommodated on the vehicle 100 or in the vehicle 100 according to the exemplary embodiment, for example at least partially in a control device or a driving assistance system of the vehicle 100. According to this embodiment, the vehicle 100 is a manually controllable vehicle 100, or a vehicle 100 that can run partially or highly automated. In addition to the device 105, the vehicle 100 according to this exemplary embodiment has a display device 110, which display device 110 is designed to display content optically and/or acoustically. For this purpose, the display device 110 has at least one image output device 112 like a screen and/or an audio output device like a loudspeaker.

The apparatus 100 has providing means 115, output means 120, transmission means 125 and image comparison means 130. The providing device 115 is designed to provide a desired display signal 135 via a transmission path 140, wherein the desired display signal 135 represents image data 145 of at least one safety information item of the vehicle 100. The output device 120 is designed to output the image data 145 of the desired display signal 135 in order to display the image data 145 as actual image content 150 on the display device 110. The transmission means 125 are configured to transmit an image content signal 155 via the transmission path 140, which image content signal 155 represents the actual image content 150, and to provide the image content signal 155 to the image comparison means 130. The image comparison means 130 are configured to compare the desired display signal 135 with the image content signal 155 in order to evaluate the completeness of the display content as non-given if there is an identified difference between the image data 145 of the desired display signal 135 and the actual image content 150 of the image content signal 155, and to evaluate the completeness of the display content as given if there is no identified difference between the image data 145 of the desired display signal 135 and the actual image content 150 of the image content signal 155.

According to this embodiment, the transmission path 140 is implemented as a transmission medium like ethernet, WLAN or APIX ((automotive pixel link)). According to this embodiment, the provision means 115 are configured so as to provide the desired display signal 135, wherein the data rate of the image data has been reduced in the case of using an image compression unit. According to this embodiment, the output device 120 is configured to output the image data 145 of the desired display signal 135 in a decoded manner in order to produce the actual image content 150. According to this embodiment, the transmission means 125 are configured to transmit the compressed image data of the actual image content 150 as image data of the actual image content 150 in order to provide an image content signal 155. Furthermore, according to this embodiment, the transmission means 125 are configured so as to transmit an image content signal 155, which image content signal 155 represents a predefined component of the actual image content 150. According to an embodiment, the predefined component is for example a key component of the actual image content 150, which is for example defined by the relevant standard ISO26262 in one of the various security levels ASIL a to ASIL D for functional security. According to various embodiments, the key components are, for example, gear displays of the fully automatic transmission, warning messages of the engine control unit and/or warning messages of the driver assistance system. According to an embodiment, non-security-critical (i.e., non-critical) components of the actual image content 150, such as, for example, time information, are not transmitted by the transmitting device 125. According to this embodiment, the image comparison device 130 is configured so as to perform similarity comparison using a predefined comparison rule at the time of comparison.

Optionally, the device 105 further has a generating device 160 according to this embodiment, the generating device 160 being configured such that: if the image comparison device 130 evaluates the completeness of the display content as non-given, a backup level signal 165 is generated, wherein the backup level signal 165 is configured to provide display content that is predetermined as a backup level. According to an embodiment, the backup level signal 165 is configured to at least partially or completely suppress the display of the actual image content 150 on the display device 110 or to display an action instruction for the driver. In this case, according to an embodiment, the backup level signal 165 is configured so as to suppress or superimpose a display of a predefined component of the actual image content 150 on the display device 110.

The apparatus 105 described herein enables functional security for display devices 110 that are subject to ethernet constraints. According to an embodiment, the display device 110 is part of the apparatus 105. The apparatus 105 and the display device 110 are hereinafter collectively referred to as a display system 170.

Many applications require that information relating to functional safety be displayed on a freely programmable display system 170. For example, it is this (but not the only) that information relating to the vehicle is displayed on a screen in the motor vehicle 100. Typical display contents with increased security requirements are for example: gear display of the fully automatic transmission, warning messages of the engine control and of the driver assistance system. In the future, expanded driver assistance messages in the area of highly automated driving will also occur on a very large scale for this purpose. The relevant standard ISO26262 defines various security levels (ASIL a to ASIL D) for the security of functions and describes the requirements of technical solutions for implementing security with which functions are classified.

In order to technically secure the display of the safety-critical functions, it is possible, unlike in the case of the use of the device 105 described here, to use a behavior in which a checksum is determined with respect to the critical display elements and the checksum in the desired image is compared with the actual image. If there is a discrepancy between the two, then an emergency display may be activated to disable the faulty message to effect a safe state. This checksum calculation of the actual image may be performed either directly at the output of the sending unit to the screen by reading back the image to be sent, or by an additional function within the screen and via a return channel, transmitting the checksum to the sending unit. The cabling of the transmission unit to the screen may in this case typically be done as a digital point-to-point connection, for example via LVDS. However, the use of inexpensive ethernet in the vehicle 100 for duplex transmission of a large number of data channels is increasing. Particularly suitable for this purpose are a series of standards for streaming (IEEE 802.1) known as Audio/Video Bridging (AVB) of the Audio/Video Bridging Task Group (Audio/Video Bridging Task Group) for: synchronized and prioritized streaming of audio and video data over a network, which standards are also used by the device 105 described herein according to embodiments. However, the alternative possible behavior patterns described above require or require significant additional computing power in the transmitting unit for reading back and evaluating the images, with the additional disadvantage of gaps in the monitoring chain, since the transmission and display sections are not adequately monitored. Alternatively, however, the checksum is calculated by employing other functions in the screen, resulting in increased complexity and cost of the screen.

The device 105 presented here now advantageously enables a method in which the following is combined with the concept of a closed monitoring chain: the solution is widely prevalent in the field of IP-based (consumer) systems for video and image transmission via compressed video streams, for example (e.g. using MPEG compression methods h.264 or h.265). To this end, the desired display signal 135 according to this embodiment is transmitted from the sending unit 175 to the screen unit 180 as a compressed data stream very efficiently via a suitable transmission medium, such as ethernet, WLAN, APIX, according to an embodiment, the desired display signal 135 having an image or video stream comprising security critical display elements. According to this embodiment, the sending unit 175 only exemplarily comprises at least the providing means 115, the image comparing means 130 and/or the generating means 160. According to this embodiment, the screen unit 180 only exemplarily includes at least the output device 120, the transmission device 125, and/or the image output device 112. The receiver module in the screen unit 180 (here illustratively in the output device 120) is configured according to this embodiment in order to decode the compressed data stream and/or to perform a recompression of the received image or video stream, for example as so-called transcoding. The recompressed data stream is then transmitted back to the sending unit 175 as the image content signal 155 via the same transmission medium. In the transmitting unit 175, the image area is compared with the safety-critical information, and according to the embodiment, a corresponding measure is taken for displaying correct information in case of content inconsistency. Thereby, a high degree of security is achieved with a low degree of additional complexity and cost.

Fig. 2 shows a schematic diagram of a display system 170 according to an embodiment. The display system 170 described in fig. 1 may be referred to herein. The display system 170 includes a transmitting unit 175, at least one bidirectional transmission path 200 or two unidirectional transmission paths 205, and at least the one display apparatus 110. According to this embodiment, the display system 170 has three of the display apparatuses 110, wherein two of the display apparatuses 110 are each connected with the transmission unit 175 via the bidirectional transmission path 200, and a third one of the display apparatuses 110 is connected with the transmission unit 175 via the two unidirectional transmission connection paths 205. According to alternative embodiments, the display system 170 has only two of the display devices 110, or has more than three display devices 110.

Fig. 3 shows a schematic diagram of the device 105 according to an embodiment. The device 105 described in fig. 1 or 2 may be referred to here. According to this embodiment, the transmitting unit 175 of the device 105 is shown in detail. According to this embodiment, the sending unit 175 includes a data processing unit 300, an image and video compression unit 305, an image and video decompression unit 310, an image comparison device 130, a graphics output unit 315, and a providing device 115, the providing device 115 being in the form of a data transmission unit. According to this embodiment, image data 145, which may also be referred to as "desired image content," is generated by a graphics output unit 315. The sending unit 175 generates the temporary desired image content 320 by means of the data processing unit 300. The temporary desired image content 320 is reduced in its data rate by the image and video compression unit 305 and the temporary desired image content 320 is transmitted via a transmission path to the display device/display devices by means of the graphics output unit 315 and the providing device 115 for display on one or more display devices of the apparatus 105.

According to this embodiment, in the image comparison device 130 in the transmission unit 175, an algorithm for similarity comparison is advantageously employed instead of comparing the same contents. In this way, it is possible to employ lossy and thus significantly more efficient compression methods. According to an embodiment, the comparison is performed with reference values generated off-line within the image comparison means 130, for example in case a cyclic redundancy check (abbreviated "CRC") or a similarity comparison is applied. In this way, the criticality of the data processing unit 300 with respect to functional safety can be reduced to a correct fault response. In this way, the calculated ASIL level of the preliminary safety-relevant representation can be partially reduced to "QM", i.e. to an evaluation of low risks, which are sufficient even without standard special measures.

Fig. 4 shows a schematic diagram of the device 105 according to an embodiment. The device 105 described in fig. 1, 2 or 3 may be referred to in this case. According to this embodiment, the screen unit 180 of the device 105 is shown in detail. According to this embodiment, the screen unit 180 includes at least one of the display devices 110, the display devices 110 each having an image and video decompression unit 400, an image and video compression unit 405, a transmission device 125 in the form of a data transmission unit, and an image output device 112.

The desired image content 410 (formerly referred to as "image data") contains not only non-critical image elements according to this embodiment, but also critical image elements in terms of functional security, for which see also fig. 5 and 6. According to this embodiment, on the display device 110, the desired image content 410 is decoded in the image and video decompression unit 400 and displayed on the image output device 112. By processing the desired image content 410, thereby becoming the actual image content 150, the actual image content 150 is displayed on one or more display devices 110 according to this embodiment, and the actual image content 150 should be secured with safety critical functions. Thus, the decoded signal 415 of the actual image content 150 is recompressed by means of the image and video compression unit 405 and the decoded signal 415 of the actual image content 150 is transmitted to the sending unit via the transmission means 125 and the transmission path. According to an embodiment, in the transmitting unit the received image content signal is received in the providing means in the form of an encoded signal of the actual image content 150 and decoded in the image and video decompression unit of the transmitting unit and/or provided to the image comparison means. The image comparison means of the transmitting unit compares the desired image content 410, which desired image content 410 was originally generated and transmitted by the data processing unit of the transmitting unit, with the received back actual image content 150, which actual image content 150 is encoded in the image and video compression unit 405 and decoded again in the image and video decompression unit of the transmitting unit.

If the image comparison device is to identify a difference between the desired image content 410 and the received back actual image content 150 in an area of the image elements defined as critical in terms of functional safety, the data processing unit of the sending unit activates the previously defined backup level for a safety-critical display according to an embodiment. To this end, according to an embodiment, a backup level signal is generated which, according to various exemplary embodiments, causes a signal mixing (aufschalking) of an emergency display with reduced content, for example "please drive in the workshop", causes a blanking of the safety-relevant display area on the display device 110, or also (as a last resort) causes a switching off of the entire display on the display unit 110.

According to this embodiment, the reverse transmission of the image or video stream of the actual image content 150 to the sending unit is advantageously limited to the respective safety-relevant areas of the entire image and therewith the amount of data to be transmitted is reduced overall. In this way, the overhead for encoding, decoding and transmission as well as for image comparison is reduced and more cost-effective components can be implemented. According to this embodiment, the reverse transmission of the image or video stream of the actual image content 150 to the transmitting unit is performed at a significantly higher compression rate, and the amount of data to be transmitted is reduced overall thereby. In this way, the overhead for encoding, decoding and transmission is reduced and more cost-effective components can be implemented. According to an embodiment, the audio output of functionally safety-relevant information is performed in parallel or exclusively to one or more audio output units, with the method of transmitting audio data backwards to a transmitting unit as described above, and with the actual audio output being compared with the desired audio output.

Fig. 5 shows a schematic diagram of a display apparatus 110 with a device 105 according to an embodiment. Here, one of the following display apparatus 110 and device 105 may be involved: the display device 110 and the apparatus 105 have been described in one of the previous figures. According to this embodiment, on the display device 110, the desired image content 410 is displayed with not only the non-critical image elements 801 but also the critical image elements 802 in terms of the definition of functional safety, using the apparatus 105. According to this embodiment, the display state of the desired image content 410 before the backup level signal is generated is shown.

Fig. 6 shows a schematic diagram of a display apparatus 110 with a device according to an embodiment. The display device 110 with the apparatus described in fig. 5 can be referred to here with the difference that according to this embodiment, correspondingly the backup level signal 165 has caused the fading out of the image element 802, which is at least critical in terms of the definition of functional safety. According to an alternative embodiment, the backup level signal 165 correspondingly causes the non-critical image elements 801 to be faded out as well, or causes an action instruction to be displayed for the driver of the vehicle.

Fig. 7 shows a method 700 for checking the completeness of display content when transmitting at least one display information for a vehicle according to an embodiment. Here, a method 700 may be referred to, which method 700 may be performed and/or manipulated by a device described in one of the preceding figures.

The method 700 includes the steps of providing 705, outputting 710, transmitting 715, and comparing 720. Optionally, the method 700 according to this embodiment further comprises a step 725 of generating. In a providing step 705, a desired display signal is provided via a transmission path, wherein the desired display signal represents image data of at least one safety information of the vehicle. In an output step 710, image data of the desired display signal is output for display on the display device as actual image content. In a transmit step 715, an image content signal representing actual image content is transmitted via a transmission path and provided to an image comparison device. In a comparison step 720, the desired display signal is compared with the image content signal to evaluate the completeness of the display content as non-given if there is an identified difference between the image data of the desired display signal and the actual image content of the image content signal, and as given if there is no identified difference between the image data of the desired display signal and the actual image content of the image content signal.

If the completeness of the display content is assessed as non-given in the step 720 of comparing, a backup level signal is generated in a step 725 of generating, wherein the backup level signal is configured to provide display content that is predetermined as a backup level.

Due to the method 700 presented herein, the check can advantageously be accomplished by transmitting the re-encoded/compressed data back over the same transmission path for comparison.

If an exemplary embodiment includes an "and/or" link between a first feature and a second feature, this is to be understood such that the exemplary embodiment has not only the first feature but also the second feature according to one embodiment, while in accordance with other embodiments either only the first feature or only the second feature.

Claims

1. A method (700) for checking the completeness of display content when transmitting at least one display information for a vehicle (100), wherein the method (700) comprises the following steps:

providing (705) a desired display signal (135) via a transmission path (140), wherein the desired display signal (135) represents image data (145) of at least one safety information of the vehicle (100);

outputting (710) the image data (145) of the desired display signal (135) for displaying the image data (145) as actual image content (150) on a display device (110);

-transmitting (715) an image content signal (155) representing said actual image content (150) via said transmission path (140) and providing said image content signal (155) to an image comparison means (130); and

-comparing (720) the desired display signal (135) with the image content signal (155) in order to evaluate the completeness of the display content as non-given if there is an identified difference between the image data (145) of the desired display signal (135) and the actual image content (150) of the image content signal (155), and to evaluate the completeness of the display content as given if there is no identified difference between the image data (145) of the desired display signal (135) and the actual image content (150) of the image content signal (155).

2. The method (700) of claim 1, wherein in the step of transmitting (715) the image data (145) of the actual image content (150) is compressed in order to provide the image content signal (155).

3. The method (700) according to any of the preceding claims, wherein in the step of providing (705) the data rate of the image data (145) is reduced in case an image compression unit (305) is used.

4. The method (700) according to any of the preceding claims, wherein, in the step of outputting (710), the image data (145) of the desired display signal (135) is decoded in order to produce the actual image content (150).

5. The method (700) according to any of the preceding claims, having a step (725) of generating a backup level signal (165) if the completeness of the display content is assessed as non-given in the step (720) of comparing, wherein the backup level signal (165) is configured to provide a display content predetermined as a backup level.

6. The method (700) according to any of the preceding claims, wherein, in the step of transmitting (715), the image content signal (155) represents a predefined component of the actual image content (150).

7. The method (700) according to any of the preceding claims, wherein the step of comparing (720) is performed using a predefined comparison rule for similarity comparison.

8. A device (105) which is set up to implement and/or handle the steps (705, 710, 715, 720, 725) of the method (700) according to one of the preceding claims in a corresponding unit (110, 112, 115, 120, 125, 130, 140, 160, 175, 180; 300, 305, 310, 315; 400, 405).

9. A computer program set up to implement and/or handle the steps (705, 710, 715, 720, 725) of the method (700) according to any of the preceding claims.

10. A machine-readable storage medium having stored thereon a computer program according to claim 9.