EP1252571B1 - Method and device for controlling a visual display unit for a rail traffic control system - Google Patents

Abstract

The invention relates to a method for displaying an image (AB) of a traffic situation of a rail track system on a display (12) of a pixel-oriented visual display unit (5) of a rail traffic control system (10), said display unit being controlled by means of a control device. According to the inventive method, the traffic situation is represented in such a manner that a viewer of the display (12) can recognize the traffic situation and can take control measures for influencing it. The aim of the invention is to provide a method which can be carried out at low costs while having a high safety standard. To this end, a visual display unit (5) is used as the visual display unit and has an internal matrix-oriented display memory (15) in which the image data required for the representation of the image (AB) are stored. The image is represented on the display against an image background whose brightness or color is adjusted according to the presence or absence of a control signal. Said control signal is automatically produced by means of the control device in an interval between the input of a user-end adjusting signal and the input of a user-end acknowledge signal.

Description

The invention relates to a method for displaying an image of a traffic situation of a railroad track on a screen of a pixel-oriented, with a control device controlled screen device of a Railway control system, wherein in the process the traffic situation such that a viewer of the screen Recognize the traffic situation and control measures to be able to influence them.

Such a method is known from the document "process-assured Message display for the Fdl workstation at Deutsche Bahn AG "(Horst Forstreuter and Achim Weitnervon Pein, Signal + Wire 86, 1994, Volume 10, pages 320 to 324) known. In this prior art method is is about a driving method for a high-resolution, pixel-oriented Screen device that is used to a railway control system belongs. Specifically, in the context of the previously known method an image of a traffic situation on a railroad track on a screen of the display device like that shown that a viewer or an operator of the Railway control system recognize and understand the traffic situation as well as control measures or operating actions for Influencing the traffic situation.

Furthermore, from EP 0 856 792 A2 a method for safe Presentation of an image on a monitor known which it allows to check if there is a small amount of hardware a track diagram of reality displayed on an engine corresponds and not by hardware or software errors is falsified. For this purpose, two independently Images are generated and stored in each image memory. Upon receipt of new information, only those of the newly constructed image information, where on the screen of the monitor is the newly displayed graphic signal in the rebuilt image sections in a different color is displayed, so for example red instead of green. So there are only selected ones Parts of the picture and thus of the screen in color changed so that just a confirmation of functioning Screen areas done.

Furthermore, from US 5,341,472 a process control the pixels of a grid or grid-oriented Screen known. The screen will be in single Subdivided subdivisions, which in a special way individually can be addressed. By addressing a selected sub-area can be a small section change the picture displayed on the screen; the remaining screen areas and pixels remain unchanged. This will be a complete rebuild of the Screen contents avoided and significantly computing time saved.

The invention has for its object to provide a method of Initially specified type to improve that it while maintaining a high safety standard especially is inexpensive to carry out.

This object is achieved by the method defined in claim 1 solved.

A significant advantage of the method consists in that it is particularly cost-effective, as a screen device with a device-internal matrix-oriented Image memory is used; because such screen devices - such. B. most types of LCD (liquid Crystal display) screens, for example, those with TFT technology - are nowadays due to their widespread use in the so-called consumer area very inexpensive to purchase. In the field of railway traffic engineering are known very high safety standards required; around To be able to achieve safety standards is to ensure that a faulty image not even on the Screen or for the user or for the operator of the railway control system immediately as is misrecognizable. In the previously known method this is achieved essentially by the fact that image memory Screen devices such as standard monitors with cathode ray tube be used; a storage of the image of the traffic situation takes place in the previously known method exclusively in the control unit controlling the video display device (PC or DV system) - specifically in the graphics card -, So that a reading or reading back of the image memory at any time for the purpose of controlling the image content readily possible is. In contrast, in the inventive Method reading back the image information from the device-internal Image memory of Bilschirmgerätes but not or not readily possible, because these days usual interfaces between control device (computer) and screen device no "read back" of image information allow; because the interfaces work exclusively unidirectional. At this point, the invention with another significant advantage; because in the inventive Procedure, the control of the screen device such that the image is on the screen a screen background is displayed whose brightness or color set differently in the presence of a control signal is considered to be in the absence of this control signal. by virtue of This process step will be aberrations very clearly visible, as explained below should: For an image with an image resolution of 1280 X 1024 Pixels (ie a picture matrix with 1280 lines and 1024 columns) is at a coding of the row and column numbering in dual number format a line address with 11 bits and a 10-bit column address is required. Is in one of the row or column bits is defective, for example such that this then permanently a logical "1" or a logical "0", so there are differences between the one actually displayed on the screen and actually desired image. Here are the effects of Bit error due to the binary coding depending on its bit position in the binary coded row or column address quite different, as can easily be clarified. The dual coding of the column numbering leads descriptively to have the most significant bit (bit position n) set, whether the respective pixel (image pixel) in the left or right half of the picture should lie; the next lower valued one Bit (bit position n-1) then indicates whether the respective pixel in the right or left picture quarter by the most significant bit of the specified image half. In In the same way, the remaining bits determine which ones Column with the least significant bit set, whether the left or the right column of the other Bits specified column pair is selected. By Simulation of image distortions caused by bit errors was recognized on the user side, that bit errors in Most significant address bit of the binary address coding especially are serious. Does it come to an error? this most significant bit, such as one Error that the bit always has a logic "0", so would on one side of the screen in case of faulty Column coding or on the upper or lower half of the screen in case of incorrect line coding no new image information is displayed anymore, but only the "old" image information. The image of the traffic situation would be partially "frozen" and not more correct. For the viewer of the screen this would be not directly recognizable because he does not know can, whether it came to a changed traffic situation is. In order to avoid such errors with respect to higher-order bits or Making the most significant bit clearly visible will be in accordance with the invention the screen background in its brightness or color is always modified if a corresponding Control signal is present. Of course, this control signal is only then to form if to check if the ad is up the screen is correct. Is it then in the presence of the Control signal to the desired full-area change of the screen background, this ensures that all Address bits, in particular the most significant address bit and also the remaining high-order address bits of the image memory, correct work. However, it comes to a banding the background of the screen, this is because one of the Address bits has not switched. This banding is i. a. very easily recognizable on the screen. In the area the railway technology is always to ensure that the display on the screen is correct when through User-side control measures the traffic situation being affected. For railway control systems, a Control measure - as, for example, the above-mentioned See publication - usually two stages; there is the operator of the railway control system first generates a control signal that the respective control measure features. Subsequently, the control action is through a corresponding change in the image of the traffic situation signaled on the screen, causing the operator is requested, a control measure confirming To generate acknowledgment signal. Only after presence the acknowledgment signal then becomes the control system side or the interlocking side the control measure turned into reality. The period after input of the control signal and before delivery of the Acknowledgment signal is therefore particularly critical, so that in This period is particularly important for a correct presentation the image of the traffic situation got to. According to the invention, the control signal is therefore in this Period generated; d. H. so that also the change of the Screen background according to the invention in this period is provided. An additional significant advantage of the invention Procedure is that in this used screen devices with device-internal image memory - As already stated above z. B. LCD screens - i. a. radiationless or very low radiation work, so that the inventive method and highest demands on the Occupational health and safety for operating personnel; be supplementary pointed out that LCD screens also have the advantage show that they are very insensitive to electromagnetic Disturbing radiation and are thus by a very high electromagnetic strength.

As part of a development of the method according to the invention It is also considered advantageous that at least on a partial surface of the screen, a grid pattern is displayed, the grid line width of the Width of a screen pixel and its grid line spacing an odd multiple of the single pixel pitch equivalent. Due to this display of the grid line pattern Namely, display errors that are due to a bit error of the least significant address bits, for an operator of the Railway control system particularly clearly recognizable; because at an error of the least significant bit is such a grid line pattern is no longer correct. Is namely the least significant bit always logical "1" or always logically equal to "0", then every other row or column no longer addressable and thus no longer "writeable", which inevitably leads to a clearly visible optical change of the grid line pattern.

The invention is also based on the object, a Indicate control device for activating a video display device, with maintaining a high safety standard particularly cost-effective images of traffic situations on railway tracks.

This object is achieved by the defined in claim 3 control device.

The advantages of the control device according to the invention correspond those already in connection with the invention Procedures have been explained. The same goes for the in the under claim described training of the invention Control device, the advantages of which are the above Statements in connection with the development of the invention Derive method.

In the above explanations was always by an operator spoken that a representation error of the grid line pattern or the screen background to recognize; Of course, the recognition of a picture error also be done by machine, for example, the image of the Video taken with a video camera and then in a computer, a machine-implemented image recognition process is subjected. As part of this image recognition process then becomes the illustrated gridline pattern or the screen background shown with a stored (correct) grid line pattern or screen background compared, and it will in case of deviation between stored and displayed grid line pattern or screen background generates an alarm signal.

Figur 1 ein Ausführungsbeispiel einer Anordnung zur Durchführung des erfindungsgemäßen Verfahrens,

Figur 2 ein Gitterlinienmuster in "Pixeldarstellung" für das Ausführungsbeispiel gemäß Figur 1,

Figur 3 das Gitterlinienmuster gemäß Figur 2 in vereinfachter Darstellung

Figuren 4a und 4b durch Adreßbitfehler verfälschte Darstellungen des Gitterlinienmusters gemäß Figur 3 und

Figuren 5a bis 5e Bildschirmhintergründe mit und ohne Adreßbitfehler.

To illustrate the invention

1 shows an embodiment of an arrangement for carrying out the method according to the invention,

FIG. 2 shows a grid line pattern in "pixel representation" for the exemplary embodiment according to FIG. 1,

3 shows the grid line pattern according to Figure 2 in a simplified representation

Figures 4a and 4b by Adreßbitfehler distorted representations of the grid line pattern of Figure 3 and

Figures 5a to 5e screen backgrounds with and without Adreßbitfehler.

FIG. 1 shows a pixel-oriented display device 5 of FIG Eisenbahnleitsystems 10. In the screen device 5 can For example, it is an LCD screen device, in particular one with TFT technology, or even a PLASMA screen device act. The screen device 5 of the railway control system 10 serves to create an image AB of a traffic situation on a railroad track not shown in the figure 1 in such a way that a viewer of the screen 12 of the screen device 5 or an operator of the railway control system 10 recognize the traffic situation and take control measures to influence them can. The video display device 5 has on the input side a device-internal, matrix-oriented image memory 15, in which required for displaying the image on the screen 12 Image data are stored or stored.

The image memory 15 is connected via an interface 20 with a Control device 25 connected, for example, by a PC or a DV system or a microprocessor arrangement can be formed. This controller 25 is available its one input E25A with not shown in the figure 1 Sensors in conjunction with those to represent the image The traffic situation requires "traffic" or "situational" data transmitted to the controller 25. With her further Input E25B is the controller 25 on in the figure 1 not shown controls connected, with where the operator of the railway control system 10 control signals S1 or acknowledgment signals S2 for influencing the traffic situation generate and feed into the controller 25 can. The control device 25 points beyond in the figure 1 not shown control outputs on which They are the user-side measures for influencing the traffic situation - determined by the control signals S1 and / or acknowledgment signals S2 - as corresponding output control signals on adjusting elements (signals, points, brakes, Conveyors, etc.) of the railway track system passes.

The control device 25, which, as already mentioned above, may be formed by a microprocessor arrangement is in this case configured or by a corresponding control program programmed to be in addition to the image the traffic situation generates a grid pattern GM and for display on the screen 12 to the display device 5 forwards.

The display of the grid pattern is done on a Subarea of the screen 12, used for the representation of the Image of the traffic situation is not needed, so i.a. in the area of one of the screen edges.

An exemplary embodiment of a grid line pattern is shown in FIG 2. This gridline pattern occupies a pixel area, passing through the pixels with the column numbers between x0 and x + 2q and formed with the line numbers between y0 and y0 + 2q is. X0 and y0 denote, so to speak, the coordinates of upper left corner of the grid line pattern. The variable q gives the distance between the grid lines of the grid line pattern and should be an odd number; for example q = "3".

FIG. 3 shows the grid line pattern according to FIG. 2 again vividly for the case q = 3 in the error-free case; So in the case that the image memory 15 is working correctly and the grid line pattern generated by the controller 25 plays correctly. As shown in Figures 2 and 3 clearly indicates, corresponds to the grid line width of Width of a screen pixel.

Below is to be explained, which representation errors occur when the memory cells of the image memory 15 can no longer be addressed correctly; it will For example, initially assumed that the least significant Address bit A (0) of the column address is no longer correct works and permanently stands "0" or "1" (A (0) = 0 or A (0) = 1). In this case, the corresponding image memory cells, whose least significant address bit A (0) = 0 or A (0) = 1 is, inevitably, the content that last gave them - So the last time you write - before failure of the address bit A (0). Regarding the Content of the disturbed cells is assumed as an assumption that the image memory 15 initially works correctly, so that the grid line pattern according to Figure 2 or 3 originally is displayed correctly, and that the defect of the image memory only then occurs. The "frozen" content the disturbed cells can thus be used for the two following Error cases are read in each case in Figure 3:

Error case 1:

First, the case will be examined that the least significant Address bit A (0) of the column address permanently set to "0" stands (A (0) = 0). In this case, the columns may be odd Column number can no longer be addressed and remain thus frozen. In contrast, the even Columns addressed twice; Concrete becomes namely in one Image cell with even column number first correct Image information inscribed. Then, if it is the next column with odd column number addressed is to be, then the addressing error occurs, because the address bit A (0) does not switch from "0" to "1" can be. This then causes the image information, which was actually intended for the next column, again inscribed in the column with the even column number becomes; the correct image content of this column will be then overwritten, with the image information for the next column with the odd column number thought were.

When examining the error case 1 so the assumption taken that the columns one after the other in the direction of increasing Column numbers are addressed successively. at fast memory description or fast screen layout thus comes visually for all columns with even column number only the wrong image content to the validity.

FIG. 4a shows the pattern resulting in error case 1 in the event that the column number x0 of the image memory cell of the upper left corner of the grid line pattern odd is; FIG. 4b shows the resulting pattern for the Case that the column number x0 is even.

Error case 2:

Now we will investigate the case that the least significant Address bit A (0) is permanently at "1" (A (0) = 1). In the case of an error 2, therefore, the columns with even column numbers are "frozen", and the odd columns are addressed twice. The addressing error is therefore always visible when the address bit A (0) is switched from "1" to "0" should. Because this is not because of the address bit error goes, when trying, gets a column with even column number to actually describe the next column addressed with odd column number, and it gets in these inscribed the image information. Subsequently, if then this next column with an odd column number on it However, this wrong image content is with the correct Overwritten image content. Depending on the speed of the Write operation or the image structure can u. U. therefore come that the error case 2 difficult or possibly only is not recognizable because the appearance of the wrong grid line pattern only very short.

In order to be able to reliably detect the error case 2 and order in addition also bit errors in other places of the binary ones To make address coding visible is in the arrangement additionally provided according to the figure 1 that the screen background in terms of its color or brightness is always changed when by the operator of the railway control system 10 Control measures to influence the Traffic situation on the railroad track made become. As already explained above, a control measure takes place in the field of railway technology mostly in two stages: In the first stage, the operator inputs a control signal S1, which indicates the type of control measure. For example a signal XY "in motion" (in driving position or in Drive display), the operator generates this Actuator signal S1 with the information "Set signal XY in motion". After entering the actuating signal S1 the railway control system shows 10 then the railroad track with accordingly marked signal, thereby clearly showing the operator which control signal he has generated. Is the ad correct? consistent with what the operator wanted as a control measure has, it generates an acknowledgment signal S2, with which the Control signal confirmed in terms of content and the corresponding command "Signal XY in motion" by the controller 25th is carried out. In the period between the Input of the actuating signal S1 and the input of the acknowledgment signal S2 must therefore be sure that on the screen 12 displayed image actually corresponds to that what generated by the controller 25 as an image has been.

In order to achieve this, control device 25 is triggered Input of the control signal S1 generates a control signal, what only then cleared again by the control device 25 is withdrawn if the acknowledgment signal S2 is present. In addition, during the period in which the control signal is present, the screen background - on which the image of the Traffic situation is shown - the whole area or at least very large area changed, for example in the color or in the brightness. How this looks concrete, the show FIGS. 5a and 5b; FIG. 5a shows the screen background in pixel representation in its original Form - ie before the change - and Figure 5b thereafter, So after the modification. For technical reasons while the change was presented in such a way that the before white pixels are then black. Of course Must have the background image modification a change in color or brightness, that the image of the traffic situation both before and after the modification is clearly visible. It would be possible, for example a brightness change from a light gray Background to a dark gray background.

FIG. 5c shows how the screen background looks like if the least significant bit A (0) of the column address - hereinafter called the first bit A (0) - is disturbed. It can be seen in Figure 5c namely a banding with a stripe width of one pixel.

Figure 5d shows what the screen background looks like, if the next least significant bit A (0) Bit A (1) of the column address - subsequently the second bit A (1) called - is disturbed. One recognizes in the figure 5d a Banding with a stripe width of two pixels.

Figure 5e shows what the screen background looks like, if related to the second bit A (1) next higher Bit A (2) - hereinafter referred to as third bit A (2) - disturbed is: The stripe width is four pixels.

Corresponding screen backgrounds result for higher-quality bit errors; in fact, the higher the "rank" of the bit, the greater the stripe width; for the i-th bit, the column width would be 2 ^i-1 pixels.

Finally, it should be mentioned that the representation of the grid line pattern can be limited to the period in which the Control signal is present. Specifically, the grid pattern would be then only after each input of a control signal generated become. Preferably, the grid line pattern should be on a Screen area, where otherwise only the Screen background is visible. This embodiment of Grid line pattern representation offers the advantage that that also the fault described above 2 operator side is immediately recognizable: namely, the grid pattern not correctly constructed, there is an addressing error in front.

Claims (4)

1. Method for displaying an image (AB) of a traffic situation in a railway track system on a display screen (12) of a pixel-oriented visual display unit (5), driven by a control device (25), of a railway control system (10),

   the traffic situation being imaged in the case of the method in such a way that a viewer of the display screen (12) can identify the traffic situation and take control measures to influence it,

      characterized in that

   use is made as visual display unit of a visual display unit (5) which has an internal, matrix-oriented display screen memory (15) in which the image data required for displaying the image (AB) are stored,

   the image (AB) being represented on the display screen (12) against a display screen background whose brightness or colour is set differently in the presence of a control signal than in the absence of this control signal, and

   the control signal being formed by the control device (25) automatically in a period between the input of a user-end actuating signal (S1) and the input of a user-end acknowledgment signal (S2).
2. Method according to Claim 1,
   characterized in that

   the visual display unit (5) is driven in such a way that it displays on at least one subarea of the display screen (12) a gridline pattern,

   whose gridline width corresponds to the width of a display screen pixel, and

   whose gridline spacing corresponds to an odd multiple of the width of a display screen pixel.
3. Control device for a railway control system

   for influencing a traffic situation on a railway track system, and

   for driving a pixel-oriented visual display unit (5) in such a way that the latter displays an image (AB) of the traffic situation on the railway track system,

      characterized in that

   the visual display unit (5) is designed with an integral, matrix-orientated image memory (15) in which the image data required for displaying the image (AB) are stored, and
   in that the control device (25) is designed in such a way

   that it drives the visual display unit (5) in such a way that the latter displays the image (AB) of the traffic situation on the display screen (12) against a display screen background whose brightness or colour is dependent on the presence of a control signal in the control device (25), and

   the control device (25) furthermore being designed in such a way

   that it forms the control signal automatically in a period between the input of a user-end actuating signal (S1) and the input of a user-end acknowledgement signal (S2).
4. Control device according to Claim 3,
   characterized in that

   the control device (25) is designed in such a way that it drives the visual display unit (5) in such a way that the latter displays on at least one subarea of the display screen (12) a gridline pattern

   whose gridline width corresponds to the width of a display screen pixel, and

   whose gridline spacing corresponds to an odd multiple of the width of a display screen pixel.

Images