FI3488303T3

FI3488303T3 - Monitoring of a display of a driver's cab of a means of transportation

Info

Publication number: FI3488303T3
Application number: FIEP17749630.4T
Authority: FI
Inventors: Andreas Ackermann; Andreas Horn; Uwe Rastofer
Original assignee: Siemens Mobility GmbH
Priority date: 2016-08-23
Filing date: 2017-07-24
Publication date: 2023-07-06
Also published as: WO2018036729A1; EP3488303B1; ES2944985T3; EP3488303A1; DK3488303T3; PL3488303T3

Claims

17749630.4 - 1 - 2016P09597WE MONITORING OF A DISPLAY OF A DRIVER'S CAB OF A MEANS OF TRANSPORTATION Description

[0001] The invention relates to a method for monitoring a display of a driver's cabin of a means of transportation. The invention also relates to a display device. In addition, the invention relates to a driver’s cabin for a means of transportation.

[0002] Displays are installed in the driver's cabin for displaying information on the current travel status of a train. The displayed information has to be reliable enough that incorrect data are not displayed to the driver. For example, a speed that is too low must not be displayed to the driver during the journey. To monitor the reliability of the displayed information, a target display is compared with an actual display. In this type of checking method, a target display is ascertained for each target value and a check code is formed therefor. In the display unit, the digital interface between the graphics card and the screen is read and an actual check code is also formed for the actual display. During the journey, a secure comparison unit checks the actual check codes by comparison with the target check codes and thus establishes whether the display is correct.

[0003] In conventional checking methods, check codes or checksums, also referred to as the actual check code, which have been obtained close to the display, are compared with a target process variable. For the comparison, either the actual check code can be translated into an actual process variable using a table and this can then be compared with the target process variable or, alternatively, the target process variable can be translated into a target check code using a table and this can then be compared with the actual check code. When producing the target check code, this is calculated as a reference check code

17749630.4 - 2 - 2016P09597WE by means of a so-called checksum prediction unit or ascertained from a table, while the actual check code is obtained by means of a checksum extractor from the actual value of the actual process variable and image information, such as pixel data, for the image representation of the value of the actual process variable.

[0004] EP 2 273 369 Bl describes a checking method in which a comparison is carried out between check codes using a lookup table. If a corresponding comparison code is identified in the process, a value assigned to this comparison code is compared with the value of the actual input variable.

[0005] DE 10 2014 214 667 Al describes a checking method for displaying an item of three-dimensional graphic information.

[0006] In US 2015/0 242 660 Al, different articles are identified by an identification code based on a prime number product.

[0007] DE 10 2009 044 555 B4 describes an apparatus comprising a division unit for splitting a data stream into a plurality of data segments and first and second check units, which carry out CRC checks on the data segments.

[0008] EP 2 988 496 Al describes a method for combining images from a vehicle camera which depict a region around the vehicle. In this case, misalignments of images to be combined are corrected.

[0009] A problem addressed by the present invention is to provide an alternative method and a corresponding assembly for monitoring a display in a driver's cabin of a means of transportation.

[0010] This problem is solved by a method for monitoring a display of a driver's cabin of a means of transportation

17749630.4 - 3 - 2016P09597WE according to Claim 1, a display device according to Claim 6, a driver’s cabin according to Claim 7, a computer program product according to Claim 8, and a computer-readable medium according to Claim 9.

[0011] In the method according to the invention for monitoring a display of a driver’s cabin of a means of transportation, an item of image information is captured by a display device. The image information from the display device was produced by the display device on the basis of a target process variable received from a vehicle control device. An actual check code is ascertained on the basis of the captured image information. The check code results from the image information, for example comprising pixel data, from an image representation of the value of the process variable on the display of the driver's cabin.

[0012] Furthermore, a power of two uniquely assigned to the ascertained actual check code using a first table is ascertained. In this context, a power of two should be understood to be a number that can be notated as an integer power with a base of 2. Such a number can, for example, be written as a binary number having a leading “1” and following digits having the value “0”. In addition, a target process variable produced by a vehicle control device is captured. In this context, a measured value to be displayed on the display of the driver’s cabin should be understood to be a target process variable. Preferably, this measured value is supposed to describe a travel status of the means of transportation, more preferably the kinematics of the means of transportation.

[0013] For the target process variable, a power-of-two sum uniguely assigned to the target process variable using a second table is captured. The power-of-two sum can be understood as a kind of expected value. In this context, the expected value should be understood to be a value which represents the “allowed” or “correct” image representations assigned to a value of a

17749630.4 - 4 - 2016P09597WE process variable. In an edge case, this expected value only represents a single image representation, the representation of which corresponds to the exact value of the assigned process variable. Alternatively, however, the expected value can also represent a plurality of image representations. A plurality of “allowed” or “correct” image representations are possible if there is a tolerance interval around the exact value of a process variable or if only the colour information differs, or both together.

[0014] Lastly, a check is carried out as to whether the image representation for the value of the target process variable is “allowed” or “correct” by it being ascertained whether the power of two assigned to the image representation by means of the actual check code is contained in the power-of-two sum assigned to the target process variable. If the power of two is contained in the power-of-two sum, the image representation of the captured target process variable can be classified as correct. If the power of two is not contained in the power-of-two sum, it has to be assumed that the image representation of the target process variable has to be classified as incorrect. A power of two should be understood to be "contained in the power-of-two sum” if the logical outcome “1” or “true” is obtained in a bitwise comparison or a bitwise AND operation between the power- of-two sum and the power of two.

[0015] Selecting an expected value as the reference variable makes it possible to assign a plurality of check codes to a single reference variable. This is because the expected value can be formed such that it represents a plurality of powers of two, which can each be assigned to different check codes. In this way, it is possible to use a whole value set of check codes as the reference variable. For example, in so doing, a slight deviation of an actual value of a process variable from a target value of a process variable can still be tested as being correct if its assigned power of two is contained in the expected value.

17749630.4 - 5 - 2016P09597WE

[0016] The display device according to the invention comprises an image production unit, which is configured to produce image representations on the basis of a target process variable produced by a vehicle control device. Part of the display device according to the invention is also an image representation unit for representing the image representations on an image display and a check code ascertainment unit for ascertaining an actual check code on the basis of the image information represented on the image display. Moreover, the display device according to the invention also comprises an image check unit. The image check unit is configured to capture a target process variable produced by a vehicle controller and to ascertain a power-of-two sum uniguely assigned to the target process variable using a second table. Furthermore, the image check unit is configured to capture an actual check code ascertained by the check code ascertainment unit and to ascertain a power of two uniguely assigned to the input actual check code using the first table. In addition, the image check unit has a check function to check whether the image representation is correct, with a test being carried out as to whether the power of two assigned to the actual check code is in the power-of-two sum of the target process variable.

[0017] A display device of this kind can be designed as a display unit which comprises the image production unit, the image representation unit, the check code ascertainment unit and the image check unit. The display device can, however, also comprise a separate image information production unit, which comprises the image production unit and the image check unit, and a display unit that is spatially separate therefrom, which comprises the image data representation unit and the check code ascertainment unit.

[0018] The driver's cabin according to the invention for a means of transportation comprises a vehicle control device for

17749630.4 - 6 - 2016P09597WE receiving sensor data relating to a target process variable and for producing a target process variable on the basis of the sensor data. The driver’s cabin according to the invention also comprises a display device according to the invention.

[0019] The essential components of the display device according to the invention can be in the form of software components for the most part. This relates in particular to the image production unit, the check code ascertainment unit and the image check unit. In principle, however, these components can also be partly implemented, in particular if particularly rapid calculations are involved, in the form of software-assisted hardware, for example FPGAs or the like. Likewise, the required interfaces between individual units can be formed as software interfaces, for example if this only involves a transfer of data from other software components. They can, however, also be formed as interfaces formed by hardware, which are actuated by suitable software.

[0020] A largely software-based implementation has the advantage that even display devices that are already in use can be retrofitted in a simple manner by means of a software update in order to operate in the manner according to the invention. In this respect, the problem is also solved by a computer program product comprising a computer program which can be directly loaded into a memory of a display device, comprising program code portions in order to perform all the steps of the method according to the invention when the program is executed in the display device.

[0021] In addition to the computer program, a computer program product of this kind can optionally comprise additional components such as documentation and/or additional components including hardware components, such as hardware keys (dongles etc.) for using the software.

17749630.4 - 7 - 2016P09597WE

[0022] For transport to the display device and/or for storage on or in the display device, a computer-readable medium, for example a memory stick, a hard drive or another transportable or built-in data medium can be used, on which the executable program sections of the computer program that can be input by a computer unit of the display device are stored. For this purpose, the computer unit can e.g. comprise one or more cooperating microprocessors or the like.

[0023] The dependent claims and the following description each contain particularly advantageous configurations and developments of the invention. In this case, in particular, the claims in one claim category can also be developed analogously to the dependent claims in another claim category. In addition, in the context of the invention, the different features of different exemplary embodiments and claims can also be combined to form new exemplary embodiments.

[0024] In a preferred configuration of the method according to the invention for monitoring a display of a driver's cabin of a means of transportation, the first table, i.e. the table which uniguely allocates powers of two to individual check codes, is produced in advance by means of the following steps: An image representation is produced for a first value of a process variable. A check code is calculated via the image representation. Furthermore, a power of two is uniguely assigned to the check code and the check code and the assigned power of two are stored in the first table. Said steps are repeated for each further possible process value, resulting in a complete table with check codes and powers of two uniguely assigned thereto.

[0025] In a preferred configuration of the method according to the invention, the second table is produced by means of the following steps: A plurality of valid image representations are selected for a first process value of a process variable. This

17749630.4 - 8 - 2016P09597WE means that the image representations are ascertained in a predetermined tolerance interval from values around a value of a process variable or representations of the process variable in different colours. Subseguently, the assigned check codes are calculated on the basis of the selected image representations. After that, a power of two assigned to the relevant check code is taken from the first table and a power-of-two sum is ascertained by adding up all the detected powers of two assigned to the first process value. The first value of the process variable is then stored together with the assigned power-of-two sum in the second table. Said steps are repeated with each possible process value to produce a complete table with process values and power-of-two sums assigned thereto.

[0026] This means that, for example, for each value of a process variable values are ascertained which are within a tolerance interval, and the corresponding check codes are ascertained for these values. Powers of two are then ascertained for the check codes ascertained in the tolerance interval using the first table. Lastly, an expected value is ascertained as the power- of-two sum of the assigned prime numbers. In this way, a tolerance interval around a process value can advantageously be defined. The tolerance interval can, for example, include values of process variables which are somewhat less than or greater than the ascertained target value of the process variable. Check codes are then also allocated to these values within the tolerance interval and different powers of two are in turn assigned to the respective check codes. From the individual powers of two, an expected value can then be calculated which represents all the powers of two and thus also check codes which are assigned to the values of the tolerance interval. Therefore, when checking whether an actual value of the process variable is correct, a check must only be carried out as to whether a corresponding power of two, which is assigned to an actual check code which has been calculated on the basis of the actual value

17749630.4 - 9 - 2016P09597WE and an item of image information, is contained in the ascertained expected value as an addend.

[0027] Particularly preferably, the means of transportation includes one of the following transportation means types: e a train, e an aeroplane, e a bus, e a lorry, e a passenger car.

[0028] In particular, in commercial public transport, measures for ensuring the safety of the passengers are particularly important. This also includes ensuring that there is correct information relating to the travel status of the means of transportation.

[0029] In a particularly effective variant of the method according to the invention for monitoring a display of a driver's cabin of a means of transportation, the target process variable includes a speed of a means of transportation. A display of the speed of a means of transportation that is correct within certain limits is particularly relevant to safety, since serious accidents can happen in particular owing to an excessive speed. Alternatively or additionally, the target process variable can also include an acceleration or deceleration of a movement of the means of transportation.

[0030] In the following, the invention is explained once again in greater detail with reference to the accompanying figures on the basis of exemplary embodiments. In the drawings: FIG 1 is a flow chart illustrating a method for monitoring a display of a driver's cabin of a train according to an exemplary embodiment of the invention, FIG 2

17749630.4 - 10 - 2016P09597WE is a flow chart illustrating steps for compiling a first table in detail, FIG 3 is a flow chart illustrating steps for compiling a second table in detail, FIG 4 is a schematic view of a driver’s cabin of a train according to a first exemplary embodiment of the invention, FIG 5 is a schematic view of a driver’s cabin of a train according to a second exemplary embodiment of the invention.

[0031] FIG 1 shows a flow chart 100 illustrating a method for monitoring a display of a driver's cabin of a train according to an exemplary embodiment of the invention.

[0032] In step l.Ia, an image representation BI of a value of a process variable is first received by an image representation unit of a display device.

[0033] In step 1.IIa, an actual check code I-PC is then calculated via the image representation BI. On the basis of a first table TABI, in a step 1.IIIa, a power of two ZP assigned to the ascertained actual check code I-PC is also ascertained. If a power of two is not entered in the first table TABI for the actual check code I-PC because it is incorrect, for example, a corresponding error response is triggered in step 1.1V.

[0034] In step 1.Ib, a value of a target process variable S-PG is received from the vehicle control device.

[0035] The target process variable S-PG can, for example, include a speed of the means of transportation represented on a display of the driver's cabin. It is assumed that a unit that ascertains the speed, for example a vehicle control device, is functioning correctly per se and only the transmission to a

17749630.4 - 11 - 2016P09597WE display and this being displayed on the display are not reliable or need to be checked. Therefore, the speed ascertained by the vehicle control device can be used as a target speed or target process variable S-PG.

[0036] In step 1.IIb, a power-of-two sum ZPS assigned to the value of the captured target process variable S-PG is taken from a second table TABZ2.

[0037] In step 1.V, it is subsequently checked whether the power of two ZP ascertained in step 1.IIIa is contained in the power- of-two sum ZPS ascertained in step 1.IIb. If this is the case, which is characterised by “y” in FIG 1, the displayed image representation (e.g. the displayed speed value) can be classified as correct in step 1.VI. Otherwise, it is ascertained that the displayed image representation (e.g. the displayed speed value) is incorrect, which is characterised by "n” in FIG

1. In this case, a corresponding error response is triggered in step 1.IV. The check as to whether a power of two ZP is contained in a power-of-two sum can, for example, be performed as a bitwise logical AND operation. If the power of two ZP is contained in the power-of-two sum ZPS, for the bit corresponding to the power of two ZP, a match with the corresponding bit of the power-of- two sum ZPS results.

[0038] The sequence from FIG 1 for checking the display is then restarted again at steps 1.Ia and 1.1b.

[0039] FIG 2 shows a flow chart 200 illustrating steps for compiling the first table TABl in detail. The steps described in FIG 2 are preferably carried out in advance, i.e. before the method shown in FIG 1 is applied. In step 2.1, an image representation BI is produced for a first value W of a process variable PG. A check code PC is then calculated in step 2.11 on the basis of the produced image representation BI. Lastly, in step 2.III, a power of two ZP is uniquely assigned to the

17749630.4 - 12 - 2016P09597WE ascertained check code PC and the check code PC and the power of two ZP assigned thereto are stored in the first table TABI. Steps 2.1 to 2.II are also repeated for each possible process value W, resulting in a complete first table TABI.

[0040] FIG 3 shows a flow chart 300 illustrating steps for compiling a second table TAB2 in detail. The second table is also preferably compiled in advance, i.e. before the method shown in FIG 1 is applied, but after the method shown in FIG 2.

[0041] In step 3.1, for a first value W of a process variable, the image representations (BI) considered to be correct are first selected. In this case, the image representations produced in FIG 2 in step 2.1 can be used. In step 3.11, for the set of image representations (BI), the associated check codes (PC) are calculated in each case. In step 3.III, the first table TABI is then input and, for the respective check codes {PC}, powers of two 1[ZP) assigned thereto in the first table TABI are ascertained. Lastly, in step 3.IV, an expected value ZPS is calculated as the sum of the assigned powers of two {ZP} and the first value W of the process variable and the expected value ZPS are stored in the second table TAB2. Steps 3.1 to 3.IV are also repeated for each of the individual possible further values w of process variables, such that a complete second table TAB? is produced.

[0042] FIG 4 schematically shows a driver’s cabin 40 of a means of transportation, for example a train. The driver's cabin 40 comprises a display device 43 and a vehicle control device 41. The vehicle control device 41 is configured to produce a process variable, for example a target process variable S-PG. The display device 43 comprises an image production unit 453a, an image data representation unit 43b, a check code ascertainment unit 43c and an image check unit 43d. The value of the target process variable S-PG is transmitted to the image production unit 43a. The image production unit 43a produces image data BI

17749630.4 - 13 - 2016P09597WE on the basis of the received process variable S-PG. The image data BI are then transmitted to the image data representation unit 43b and are displayed there. An actual check code I-PC is ascertained by the check code ascertainment unit 43c on the basis of the displayed image information BI. The ascertained actual check code I-PC is then transmitted to the image check unit 43d. The image check unit 43d additionally obtains a value of the target process variable S-PG from the vehicle control device 41 and performs a comparison of the target process variable S-PG with the actual process variable I-PG according to steps 1.I to 1.VI illustrated in FIG 1.

[0043] FIG 5 shows an assembly 50 that is very similar to the driver's cabin 40 illustrated in FIG 4 according to an alternative exemplary embodiment. The driver's cabin 50 shown in FIG 5 also comprises a vehicle control device 41. Unlike in the assembly shown in FIG 4, in FIG 5 the image production unit 43a and the image check unit 43d are accommodated in a separate image information production unit 51 and the image data representation unit 43b and the check code ascertainment unit 43c are arranged separately therefrom in a display unit 52. Such a split into an image information production unit 51 and a display unit 52 is described in WO 2015/082331 Al, and reference is made to its content, which is hereby incorporated into the present application.

[0044] In conclusion, it is once again noted that the above- described methods and apparatuses are merely preferred exemplary embodiments of the invention and that the invention can be varied by a person skilled in the art without departing from the scope of the invention, providing that it is specified by the claims. For the most part, the method and the apparatus have been explained in connection with a display in a driver’s cabin of a train. Said method is, however, not limited to the use in a driver's cabin of a train, but rather it can also be used in other means of transportation. For the sake of completeness, it

17749630.4 - 14 - 2016P09597WE is also noted that the use of the indefinite article “a”, “an” or “one” does not exclude the features in question also being present in a plurality. Likewise, the term "unit” does not exclude this also consisting of a plurality of components, which can optionally also be spread out in space.

[0045] The invention is specified by the accompanying independent claims. The dependent claims specify preferred exemplary embodiments.