HK1187580B - Pantograph damage and wear monitoring system - Google Patents

Description

Pantograph damage and wear monitoring system

The application is a divisional application of an invention patent application with the application date of 2008, 8 and 6, and the application number of 200880102082.3, and the name of the invention is "pantograph damage and wear monitoring system".

Technical Field

The invention described herein relates to locomotive pantographs (pantographs). In particular, although the scope of the present invention is not necessarily limited in this respect, the present invention relates to an automatic pantograph damage and wear monitoring system.

Background

Most electrified trains utilize pantographs to transmit power from an overhead line to the train. The pantograph of modern high-speed, electrified trains includes a carbon current collector (carbon current collector). These carbon current collectors typically include a carbon block support and a carbon block contacting the wire. The carbon block serves in particular to minimize wear on the overhead line. The main problem with carbon blocks is that they are susceptible to breakage damage. Misalignment, excessive arcing, and constant friction of the electrical sectioning equipment can all cause significant damage to the carbon blocks. Such damage, if undetected and repaired, may typically cause a derailment and/or damage to the pantograph and thus render the train inoperable. In order to detect damage to the pantograph, it is common practice for railway staff to perform manual inspections at regular intervals. This process requires the transfer of the train to be inspected to a maintenance station, electrical isolation of the overhead lines and access to the train roof. The labor costs and downtime associated with such an inspection process are clearly undesirable. Various systems have been developed to avoid manual testing of pantographs. GB1374972 and GB2107662 describe systems for measuring pantograph damage in which a tube is placed in a cavity of a pantograph current collector. If sufficient damage is done by the pantograph, the pipe bursts causing a drop in system pressure. This loss is detected and the system automatically lowers the pantograph, thereby preventing further damage to the pantograph and/or overhead line. EP- ｃA-0269307, DE-U-8803377.5 and EP- ｃA-0525595 describe systems in which optical fibres are embedded near the wear surface of the pantograph current collector. The optical signal is transmitted in the fiber and if damage to the fiber is caused, a loss of the optical signal in the fiber indicates pantograph damage and/or wear. Another method described in engineering integrity, Volume19, March2006, pp.12-17 employs laser assisted image processing techniques to automatically detect pantograph carbon collector wear.

Although the systems described above are effective in monitoring pantograph damage and/or wear, they have the disadvantage of being cost prohibitive. The system described in engineering integrity, Volume19, March2006, pp.12-17 has the additional disadvantage that the locomotive must be transferred to a designated monitoring station and therefore not be taken into account for normal maintenance. Moreover, the system can only ensure measurement accuracy if the locomotive is traveling at less than 12 kilometers per hour (kph) at the monitoring station.

It is an object of the present invention to provide a cost effective system that automatically monitors the status of a pantograph while a locomotive including the pantograph is in normal service. It is also an object of the present invention to overcome or ameliorate one or more of the disadvantages or problems described above, or at least to provide the customer with a useful choice.

Disclosure of Invention

According to a first aspect of the present invention, there is provided a system for assessing the condition of a pantograph, the system comprising:

a rail-side pantograph monitoring station for capturing at least one image of a pantograph while a locomotive including the pantograph is in normal service, wherein the monitoring station includes a first image capture device positioned below the pantograph and at an oblique angle relative to the pantograph;

a station management system for analyzing at least one image captured at the monitoring point and determining a state of the pantograph; and

a user interface for controlling the station management system and indicating whether a pantograph is damaged and/or worn.

According to a second aspect of the present invention there is provided a computer system arranged to analyse whether a pantograph is damaged and/or worn, the system comprising:

a computer; and

a program running on a computer, wherein the program accomplishes the following tasks:

receiving at least one command from a sensor and, upon receipt of the at least one command, activating at least one image capture device to capture at least one image of the pantograph at a monitoring station, wherein the at least one image capture device comprises an image capture device positioned below and at an oblique angle relative to the pantograph;

analyzing at least one image captured by the at least one image capture device for signs of damage and/or wear; and

the results of the analysis are provided to an output device.

According to a third aspect of the present invention there is provided an automated method for determining the status of a pantograph, the method comprising the steps of:

detecting a presence of a locomotive at a monitoring station;

detecting a presence of a pantograph at a monitoring station;

upon simultaneous detection of the locomotive and the pantograph at the monitoring station, activating an image capture device, thereby capturing an image of the pantograph, wherein the image capture device is positioned below and at an oblique angle relative to the pantograph;

analyzing the image of the pantograph to determine whether the pantograph is damaged and/or whether the carbon current collector is worn; and

reporting the results of the analysis to the end user.

With regard to the first embodiment defined above, the monitoring station comprises:

a data transmission device;

at least one rail side mounted sensor ("locomotive sensor") for detecting a locomotive entering a surveillance site;

at least one rail-side mounted sensor ("pantograph sensor") for detecting a position of a pantograph at a monitoring point;

at least one image capture device that captures at least one image of the pantograph at a monitoring point; and

a sensor interface that receives input from the sensor and commands the at least one image capture device to capture at least one image of the pantograph at the monitoring point.

The data transmission device facilitates communication between the sensor, the sensor interface, the at least one image capture device, and the station management system. The data transfer device can be a cable, such as a coaxial cable, an ethernet cable, a wireless connection, or any other device capable of performing the required task.

The image capture device is preferably a high resolution camera, but other imaging devices capable of accomplishing the required tasks may be utilized. In a preferred embodiment, the monitoring station comprises two high resolution cameras, wherein a first camera is positioned to capture a profile image of a pantograph comprising at least one carbon current collector, and a second camera is positioned to capture an image of a pantograph comprising at least one pantograph angle. Preferably, the first camera is positioned below the pantograph at the surveillance point and at an oblique angle relative to the pantograph ("side position"). Preferably, the second camera is positioned above the pantograph at the surveillance point ("top position"). Typically, the first image capturing device further comprises a back screen. The back screen is preferably white. It will be appreciated that the back screen will be mounted behind the focus of the first camera and within the field of view of the camera, so that when the first camera is activated, the captured image is the outline of the pantograph relative to the back screen. It is also preferred that the back screen is illuminated. It will be appreciated that during the day, natural lighting is often sufficient, while night operation requires the use of lights to illuminate the back screen.

The sensor may be any suitable sensor, which may be an optical, ultrasonic or microwave sensor, but is preferably an infrared sensor. In a preferred embodiment, the monitoring station comprises two sensors for detecting the position of the pantograph at the monitoring point, wherein a first sensor ("top position sensor") is positioned to identify the point of the pantograph within the field of view of the top position image capture device, and wherein a second sensor ("side position sensor") is positioned to identify the point of the pantograph within the field of view of the side position image capture device. Preferably, the sensor is in communication with the image capture device such that the image capture device is activated when the pantograph is detected by the sensor. Those skilled in the art will recognize that the pantograph monitoring system may be implemented without sensors. It will also be appreciated that such an implementation is an inefficient use of processor time, as image capture and analysis is not performed at the monitoring point and in the case of an organic vehicle.

Preferably, the monitoring station further comprises at least one track side mounted sensor ("locomotive identification sensor") to capture locomotive identification details at the monitoring point. Typically, the locomotive identification sensor is an Automatic Vehicle Identification (AVI) tag decoder. The AVI tag decoder obtains information relating to the vehicle identification number of the locomotive at the monitoring point. Other information may also be obtained from the AVI tag decoder, such as the type of locomotive that may be later used to filter extraneous tag information. It will also be appreciated that auxiliary information relating to the locomotive at the monitoring point may be obtained by querying a database associated with the decoded vehicle identification number.

Preferably, the sensor interface is in the form of a circuit, wherein the circuit performs the steps of:

receiving an input from a first track side sensor ("locomotive sensor") indicating that the locomotive is at a surveillance point;

receiving input from a second track side sensor ("pantograph sensor") indicating that a pantograph is at a monitoring point;

filtering and shaping the input received from the rail side sensor; and

when inputs from the locomotive sensor and the pantograph sensor are received simultaneously, commands are provided to the image capture device to obtain an image of the pantograph.

Preferably, the sensor interface circuit further comprises the steps of: when inputs from the locomotive sensor and the pantograph sensor are received simultaneously, a command is provided to at least one locomotive identification sensor to capture details of the locomotive at the monitoring point.

The steps provided above describe the process performed by the sensor interface circuit upon receiving a single input from the pantograph sensor. It will be appreciated that the above steps may be repeated for one or more sensor inputs emanating from one or more pantograph sensors. It will also be appreciated that it is necessary for the sensor interface to simultaneously receive input from the locomotive sensor and the pantograph sensor before providing commands to the image capture device to avoid false triggering from objects such as birds and insects that may be detected by the pantograph sensor.

Preferably, the station management system includes:

a computer; and

a program running on a computer, wherein the program performs one or more of the following tasks:

receiving user input from a data input device;

receiving at least one command from the sensor interface and directing at least one image capture device to capture at least one image of the pantograph at the monitoring point;

analyzing locomotive details from the AVI tag reader and assigning those details to at least one image of the pantograph at the monitoring point;

analyzing at least one image captured by at least one image capture device for evidence of damage and/or wear; and

the results of the analysis are provided to an output device.

Preferably, the program further performs at least one of the following tasks:

controlling illumination of the back screen;

calibrating exposure and gain settings of at least one image capture device;

receiving an input from a user, wherein the input modulates an analysis of a pantograph image; and

the exposure time and video gain of the at least one image capture device are automatically adjusted.

The program may be a multi-threaded program.

It will be appreciated that the program automatically initiates the backlighting when a locomotive is detected at the monitoring point and the at least one image capture device detects that there is insufficient light to capture an appropriate image of the pantograph. Alternatively, the back screen may be permanently illuminated. Preferably, the back screen is uniformly illuminated. It will also be appreciated by those skilled in the art that this is necessary to ensure consistency between captured images. Too long an exposure time may introduce motion blur from faster moving trains, while high gain values may result in excessively noisy images. Furthermore, it will be appreciated that if the illumination source exhibits predictable brightness variations, such as 100Hz power wave fluctuations when operated by a 50Hz AC mains supply, it is convenient to configure the apparatus to use a frame rate that maximizes the illumination difference between successive images; this minimizes the chance of taking more than one dark image in sequence.

Preferably, the analysis for determining damage and/or wear comprises the steps of, when an image of the pantograph is captured by the side position device:

receiving an input from a side-position image capture device, wherein the input represents an image of a field of view of the device;

matching an image of a pantograph within the input image with a predefined model representative of a known pantograph type;

calculating coordinates of the pantograph within the input image using the matching model;

using the coordinates calculated in the previous step to extract at least one image of the area of the pantograph from the input image; and

analyzing the at least one image of the pantograph region to determine whether the pantograph is damaged and/or the at least one carbon current collector is worn.

Preferably, the pantograph within the input image is matched to a predetermined model representing a T-or Y-pantograph configuration. As the name suggests, the T and Y pantograph configurations are T-shaped and Y-shaped.

At least one image of an area representing the contour of the at least one carbon current collector is extracted from the input image when the image of the pantograph is captured by the side-position image capturing device. It will be appreciated that the Y-pantograph includes two carbon current collectors. Preferably, when the input image matches a model representing a Y-pantograph configuration, two carbon current collector contour images are extracted from the input image. Typically, only one carbon collector profile image is extracted from the input image that matches the model representing the T-shaped pantograph. It will be appreciated by those skilled in the art that only one image can be extracted from the input image, since the contour of the far current collector is obscured by the horizontal rod of the pantograph.

When the image of the area representing the contour of the at least one carbon current collector is captured by the side position image capturing device, the wear analysis preferably includes the steps of:

determining the distance between a surface contour line representing the bottom edge of the carbon block support and a surface contour line representing the top edge of the carbon block; and

identifying an area in which the distance measured in the previous step falls below the minimum acceptable distance.

When an image of an area representing the outline of at least one carbon current collector is captured by the side position image capturing device, the damage analysis preferably includes the steps of:

creating a "rainfall" pattern in which the area between the bottom of the image and the surface profile representing the top edge of the carbon block is filled with vertical lines;

creating a containment area having a circle with a fixed radius on a surface profile representing the top edge of the carbon block; and

the rainfall pattern is subtracted from the enclosed area and the damaged area is identified.

Preferably, when an image of the pantograph is captured by the top position device, the analysis for determining the image comprises the steps of:

receiving an input from a top position image capture device, wherein the input represents an image of a field of view of the device;

matching an image of a pantograph within the input image with a predefined model representing a known pantograph type;

calculating coordinates of a pantograph angle within the input image using the matching model;

identifying a damaged pantograph bow angle by comparing the bow angle identified in the above step with a predefined model representing a particular bow angle design.

It will be appreciated that the pantograph corners may take the shape of the letter V or Y or a trifurcated design comprising a long straight strip as a central prong surrounded by shorter curved prongs. It will also be appreciated that Y-style pantographs typically include a bow corner in the shape of the letter V or Y, and T-shaped pantographs typically include a bow corner having a long straight strip as the central prong surrounded by shorter curved prongs.

A computer includes a processor or microprocessor. It can be stand alone or portable. Preferably, the computer is connected to one or more computer networks. The computer network can be a local area network, a wireless local area network, a wide area network, or an ethernet network.

The output means may comprise one or more of: visual displays, such as computer monitors; storage devices, such as computer hard disks; a relational database; a networking device; or a physical output device such as paper. The output means may also include electronic data transfer means for transferring data to a database running on a computer remote from the station management computer. For example, the results of the analysis may be written as image and text files on a computer hard drive; sent via email and/or SMS; or to a central database server such as microsoft sqlserver2005ExpresseditionSP 2. The results of the analysis may be stored on the station management computer or on a remote computer.

The user interface includes a data input device and an electronic display device. The data input device may comprise a keyboard and a keystroke device or a voice data input device. The data input by the user may control the tasks performed by the station management system or modulate the manner in which the end user views the analysis results.

The display device can be an electronic display device, such as a computer display window. The display device can be a Graphical User Interface (GUI) displayed on a computer display window. The GUI may be executed as a program application on a station management computer or on a computer in communication with the station management computer. The GUI preferably provides an interface to the station management system and associated databases serving the results of the analysis. The GUI may also modulate the way the end user views the analysis results. The GUI can be a Windows-based application or a web-based application. The GUI preferably receives input from a data input device.

The user interface may be disposed at a point remote from the track-side monitoring station and the station management system. In a preferred embodiment, the user interface is a display on a computer that is in communication with the track-management system and is disposed at a remote point. In a particularly preferred embodiment, the user interface is a GUI running on a remote computer that receives input from a user and controls tasks performed by the station management system, and displays results of the pantograph damage and wear analysis.

A locomotive that includes a pantograph is in normal service if it is passing on a main, branch or service line. If the locomotive is located in a garage or the same place or isolated from the overhead line, it is not in normal service. Preferably, the locomotive is traveling at a speed of no less than 12kph when in normal service. More preferably, the locomotive is traveling at a speed of no less than 12kph and no more than 80kph when in normal service.

In order that the present invention may be more readily understood and put into practical effect, one or more preferred embodiments thereof will now be described, by way of example only, with reference to the accompanying drawings.

Drawings

Fig. 1 is a schematic diagram of a pantograph monitoring system.

Fig. 2 is a field of view from the side position image capturing apparatus after startup.

Fig. 3 is a field of view from the top position image capture device after startup.

FIG. 4 is a sensor interface timing diagram.

FIG. 5 is a schematic diagram depicting a sensor interface.

Fig. 6 is a flow chart representing a program segment of the station management program that analyzes whether the carbon current collector of the pantograph at the monitoring point is worn.

Fig. 7 is a flowchart representing a program segment of the station management program that determines whether or not the constituent bow angle of the pantograph at the monitoring point is damaged.

Fig. 8 shows the analysis results in which wear and damage of the carbon current collector have been detected.

Fig. 9 shows the result of an analysis in which pantograph angle damage has been detected.

Fig. 10 shows the analysis results in which damage and abrasion of the carbon current collector have been detected.

Detailed Description

Referring to fig. 1, there is shown a surveillance system 1 installed at a surveillance site, comprising: top position sensors 2 and 3; side position sensors 4 and 5; and a locomotive sensor 6. When a pantograph is present at the monitoring station, the signals emitted from the sensors are received by the sensor interface 7. The sensor interface 7 includes a sensor signal conditioner 8 and an interface circuit 9. Upon simultaneous reception of a signal indicative of the presence of a locomotive at the monitoring station and a signal indicative of the presence of a pantograph at the monitoring station, the interface circuit 9 splits the signals into two signal streams. The first signal stream starts the AVI tag readers 10 and 11, which AVI tag readers 10 and 11 capture the serial number of the locomotive at the monitoring point. Data received from the tag readers 10 and 11 is converted into a USB format by the converter 101 (e.g., RS422 for USB) and enters the station management system 12 running on the computer 13 via the USB hub 102, the data being stored at the computer 13. The second signal stream is processed by the digital I/O to USB converter 14 and received by the system 12, which in turn triggers the activation of the image capture device (reference numeral 15 or 16). The image obtained by the image capturing device 15 or 16 is then received by the station management system 12, which station management system 12 analyzes the obtained image to estimate whether the pantograph is damaged and/or the constituent carbon current collectors are worn. Remote access to the pantograph damage and wear analysis results is facilitated by a connection 17 connecting the computer 13 to a computer network. The AVI tag readers 10 and 11, the sensor signal conditioner 8, and the image capture devices 15 and 16 are connected to a power supply 103 (e.g., 24 vdc).

It will be appreciated that a locomotive comprising a pantograph will be assessed by the monitoring system 1 while in normal service, meaning that the locomotive is traveling on a main, branch or service line comprising the monitoring point and typically traveling at a speed of no less than 12kph and no more than 80 kph.

The computer 13 includes a Central Processing Unit (CPU) that interfaces with a data storage device that is machine-readable and tangibly embodies a program of instructions executable by the CPU. These storage devices include RAM, ROM, and secondary storage devices such as magnetic and optical disks and disk drives. One or more memory devices carry instructions for execution by the CPU to perform the methods of embodiments of the present invention. These instructions will typically have been installed from an installation disk (e.g., an optical disk), although they may also be provided in a memory integrated circuit or from a remote server facility via a computer network. The instructions constitute a software product that, when executed, causes the computer system 13 to operate as a pantograph damage and/or wear detection system, and in particular to implement a method that will be described later with reference to a number of flow diagrams.

It will be appreciated by those skilled in the art that the programming of the software product directly reflects the method of the invention and that preferred embodiments thereof will be described. In the following method, various variables and data are manipulated. It will be appreciated that during operation of a computer system in which the method is implemented, the respective registers of the CPU will be incremented and data written to and retrieved from the secondary storage and RAM by virtue of electrical signals propagating along the computer system's conductive bus. Thus, when a computer system executes software to implement a method according to an embodiment of the invention, physical effects and transformations occur within the computer system.

Referring to fig. 2, a field of view from the side position image capturing apparatus after startup is shown. There is shown a Y-bar pantograph 18 comprising two carbon current collectors 19 and 20 in contact with an overhead line 21. Also shown is a suspension cord 22 suspended over the contact wires. The collector is outlined with respect to the white back screen 23. Figure 2 also clearly shows that each carbon current collector 19 and 20 comprises a carbon support 24 and a carbon block 25.

Referring to fig. 3, the field of view from the top position image capture device after startup is shown. A Y-pantograph is shown including Y-shaped pantograph corners 26 and 27.

Referring to fig. 4, a sensor interface timing diagram is shown depicting sensor output signals 28, 29 and 30 emanating from locomotive sensor 6, top positioned pantograph sensor 2 or 3 and side positioned pantograph sensor 4 or 5, respectively. These sensor output signals are received by the sensor interface 7. It will be appreciated that the lines represent output signal values as a function of time. When a locomotive about 17m long is detected by the locomotive sensor, a high output signal is received by the sensor interface for a substantial duration. When the sensor interface receives both the high output signal 28 from the locomotive sensor and the pantograph signal 29 or 30, the sensor interface 7 triggers a command signal 31 or 32 sent to the image capture device 15 or 16 via the station management system 11. The simultaneous receipt of high output signals 28 and 29 or 30 from the locomotive sensor and the top or side pantograph sensor triggers a command 33 or 34 to the AVI tag readers 10 and 11 to capture the locomotive serial number.

Referring to fig. 5, a schematic diagram depicting a sensor interface 7 is shown, the sensor interface 7 including a switch matrix 35, a digital I/O to USB converter 14 connected to a serial port of a computer 13 (not shown), and drivers 36 and 37 controlling the AVI tag readers 10 and 11. The switch matrix 35 receives the bounce (de-bound) and pulse shape signals from the pantograph sensors 2 to 5 and the locomotive sensor 6. Upon receiving a high output signal from the sensor, the switch matrix provides commands 38 and 39, which commands 38 and 39 are converted to an ASCII character signal stream and transmitted to the computer 13 via the serial port. The switch matrix 35 also provides commands 40 and 41 to the AVI tag reader drivers 36 and 37.

Referring to fig. 6, there is illustrated a flow chart representing a program segment of the station management program, hereinafter referred to as PanCam, for analyzing whether or not the carbon current collector of the pantograph at the monitoring point is worn. Side view images of the pantograph at the surveillance point are captured by a high resolution camera. The image data captured by the camera is then analyzed by the program. The program calls a plurality of subroutines that convert the image data. PanCam uses a HALCON machine image library, published by mvtecsoftware gmbh, to provide basic image processing tools such as morphology, line finding, and pattern matching. The subroutine is typically called by PanCam in the following order:

EquHistoImage () modifies the input image so that the distribution of values in its intensity histogram is approximately equal across all values. PanCam uses this result as an output image because the result typically has better contrast characteristics for human viewing.

CopyImage () is called to copy the input image, but it reduces the color depth of the image (the original 12 bits produced from the camera) to 8 bits. This is because some HALCON operators (the most significant pattern matches) only receive images with 8 bit depth.

The program then calls FindShapeModel () to match the predefined model of the backplane against the image. By comparing the coordinates of the matching model with the fixed coordinates of the base plate where PanCam expects, PanCam can compute coordinate offsets to adjust the fixed region of interest in subsequent processing. These adjustments may be necessary due to movement of the camera's view angle caused by maintenance work or other disturbances.

Using the background coordinate adjustment offset, the program calls MoveRegion () to adjust the backplane region of interest. GrayHisto () is then called to compute the intensity histogram over the region of interest.

The purpose at this point is to find the appropriate intensity values to use as thresholds in the binary segmentation so that the pantograph profile (profile) can be extracted from the backplane. PanCam excludes a fixed percentage of the top and bottom of the histogram from the search to avoid incorrectly selecting the minimum or maximum intensity value for segmentation, and then invokes SmoothFunct1dGauss () to perform Gaussian smoothing on the truncated histogram.

Getyvaluefect 1d () finds the local minimum within the smoothed histogram and iteratively expands the 'window' around these points to maximize the ratio of the window width to the square of the window height, where height is the maximum histogram bin (bin) count within the window and width is the range of pixel values. The selected window has the widest aspect ratio of all such windows in the truncated histogram. PanCam then selects the midpoint of the window, which maximizes this aspect ratio as a preliminary 8-bit segmentation threshold.

In HALCON, for images with color depths greater than 8 bits, the histogram operator automatically maps to the range 0 to 255. PanCam must first call minmaxgay () on the image area used to generate the histogram to find the minimum and maximum values, then it can perform the necessary calculations using a linear transformation to map the preliminary 8-bit threshold onto the corresponding 12-bit segmentation threshold. PanCam then performs segmentation of the pantograph profile using the threshold.

Similar to step 4, PanCam adjusts the area where it can reliably check the pantograph profile. PanCam uses HALCON to perform region interaction () on segmented pantograph contours and valid regions of interest.

Again using MoveRegion (), PanCam adjusts the search area over which the pantograph model is matched. PanCam calls AddChannels () and findscaledshapemodes () to search for multiple pantograph matches in a single operation. The match with the highest score indicates the best match and thus the most likely identification of the pantograph type.

HALCON uses a pyramid matching algorithm that first matches the model at a lower resolution to improve the speed of the matching operation. Sometimes this results in false matches due to reduced resolution, so PanCam calls TestRegionPoint () to check that the matching model does indeed lie within the fixed search area. Ignoring false matches, otherwise PanCam calls GetShapeModelContourXors (), AffiniTransContourXld (), and GenRegionContourXld (), to display the matching model on the output image.

Once PanCam has identified and located the pantograph, PanCam calls genregionpolynfiled () to create a region around it that is considered a carbon current collector, using the fixed coordinate offset with the pantograph model position as a reference point. PanCam will also display these regions on the output image.

PanCam again uses MoveRegion () to adjust for a predefined area in which the top edge portion of the floor is considered to be located in the image. If the carbon current collector area overlaps an excessive proportion of the floor top edge area, PanCam considers the carbon current collector to be in a position where analysis is unreliable, and does not perform any further processing on the carbon current collector.

PanCam examines the pixel area of the carbon current collector region. If the area is zero, no data to be processed is found in this image: PanCam does not process the image further and reports "no pantograph". This covers rare situations where PanCam may miss the position of the pantograph altogether and would otherwise produce incorrect diagnostic information.

Before PanCam can begin to inspect for damage and wear, it is necessary to remove disturbing artifacts in the carbon current collector profile. PanCam first removes the contours of the overhead lines in the image using the Opening () morphological operator because these intersect the top edges of the carbon current collector contours. PanCam performs this operation on two non-overlapping regions using a different structural element for each region to account for the varying slope of the top edge of the carbon current collector profile. In each case, PanCam also adjusts the location of the area over which the opening is made based on the background offset calculated in step 4.

PanCam continues to filter the carbon collector profile by calling SelectShape () to remove segments of the profile that are too small and too far apart to be considered part of the carbon collector. Dark spots on the floor, which can accumulate over a long period of time, often cause these false contours.

PanCam finds the step in the carbon current collector by enlarging the carbon current collector profile area with vertical lines (step), creating a "rain" effect in which any portion under the top profile of the carbon current collector is filled. PanCam also performs closing using a large circled area on the original carbon current collector profile. By subtracting the rainfall area from the enclosed area, any remaining area may indicate a 'step' break in the carbon.

PanCam needs to limit the resulting area calculated in the previous step to eliminate artifacts from rainfall operation, which sometimes leave unrecognizable shapes near the corner of the pantograph. PanCam again adjusts the fixed region of interest according to the background offset, then invokes the interaction () on the valid region and result of the previous step.

In the final part of the damage analysis, PanCam calls OpeningCircle () with a smaller radius to remove minor artifacts from the results of the previous step. Then, PanCam assumes that there is a possible step damage to the carbon current collector if any discrete region in the result has an area greater than a fixed threshold. In this case, PanCam also displays the result on the output image by enlarging the damage area and printing the outline (outline) (leaving the unmasked highlighted damage).

If the pantograph is of the 'Y' type, steps 16 to 18 are repeated for a second carbon current collector. It will be appreciated that only one carbon collector profile image is extracted from the input image that matches the model representing the T-pantograph, as the profile of the far collector is obscured by the horizontal rods in the pantograph.

For wear analysis, PanCam takes carbon current collector profiles that have been processed to remove overhead lines and other artifacts. If there is more than one discrete region in this profile, PanCam discards the profile and proceeds to a second carbon current collector.

PanCam must determine how much the carbon current collector is affected by the corresponding scaling, since the pantograph may be in different positions in different images relative to the camera. PanCam uses the LinesGauss () line find operator to locate the overhead cable. PanCam then calls selectsharx 1d () to just select a straight line (as opposed to a curved or curved line) as appropriate, and calls selectcontinrsx 1d () to select a line that extends in the same direction because it is expected to be an overhead line. PanCam then calls the straight line formula (using Tukey approximation) that FitLineContourX1d () used to calculate the remaining lines and takes the intersection between the result and the top edge of the carbon current collector. PanCam uses this intersection point as a reference point for projection scale adjustment.

Using the reference points calculated in the previous step, PanCam applies the cylinder coordinates to a fixed predetermined formula to calculate an adjustment factor for the minimum carbon height threshold. Carbon current collectors closer to the camera may result in a larger carbon height threshold than carbon current collectors further from the camera, which corresponds to projected scaling of the pantograph as it approaches the camera.

Once PanCam has determined the minimum receive height, it uses the Opening () operator and uses the vertical line of that height as a structural element. PanCam then calls Difference () to subtract the open result from the original carbon current collector profile. Any areas remaining indicate potential excessive carbon wear, and PanCam will identify the carbon current collector as worn if the width of the remaining image area is large enough. In this case, PanCam also highlights the worn area on the output image by enlarging the area and its displaying its appearance.

If the pantograph is of the 'Y' type, steps 20 to 23 are repeated for the second carbon current collector. It will be appreciated that steps 20 to 23 are not repeated if the pantograph in the input image matches the model representing a T-pantograph. This is because the profile of the distal collector is obscured by the horizontal rods in the pantograph.

Referring to fig. 7, a flowchart showing a procedure of determining whether or not a constituent bow angle of the pantograph at the monitoring point is damaged is illustrated. A perspective overhead view image of the pantograph at the surveillance point is captured by a high resolution camera. The image data obtained by the camera is then analyzed by the program. The program calls a plurality of subroutines that convert the image data. The subroutine is typically called by the program in the following order:

EquHistoImage () modifies the input image so that the distribution of values in its intensity histogram is approximately equal among all values. PanCam uses this result as an output image because the image typically has good contrast characteristics for human viewing.

CopyImage () is called to copy the input image, but it reduces the color depth of the image from the original 12 bits produced by the camera to 8 bits. This is because some HALCON operators (the most significant pattern matches) only receive images with 8 bit depth.

Prior to searching for the pantograph, PanCam first attempts to match a predefined rail trajectory model with respect to the image. If HALCON can successfully find a set of tracks in an image, PanCam assumes that there are actually no locomotives in the image, as the locomotives would otherwise obscure the image of the track. In this case, PanCam rejects the current image and moves to the next for processing.

PanCam calls reduce Domain () to reduce the search area to a predetermined area where pantograph matches within the desired image. PanCam then calls FindScaledShapeModel () to match against a plurality of predefined pantograph models. Regarding pattern matching in side view processing, PanCam must check for false matches using the TestRegionPoint () operator, and if the check fails, reject pantograph matches because it is too far outside the desired pantograph region. PanCam uses the scale factor returned from pattern matching as a scale factor for shifting in later matching operations to accommodate perspective scaling.

After the pantograph is located and identified, the PanCam (for side view pattern matching) uses getsharmodelcontrours (), AffineTransContourXld (), and GenRegionContourXld (), to display the matching model on the output image.

PanCam calculates a new search area for searching for the bow angle on the left and right sides of the pantograph using the coordinates of the matching pantograph and a set of predefined coordinate offsets (scaled by the scaling factor determined in step 4). PanCam then performs multiple pattern matching operations on each side once to check for the presence of a bow angle.

For a Y-pantograph, the matching operation uses a single model of the bow angle. However, for a T-pantograph in which the pantograph angle includes three separate prongs, PanCam first looks for a long, central pantograph angle portion. Assuming successful pattern matching, PanCam then generates two more search regions, which are calculated from the position of the corner portion of the bow and a set of scaled predefined coordinate offsets. PanCam then performs yet another pattern matching operation to check for the presence of the remaining two corner portions.

PanCam declares bow corner damage if the pattern matcher fails to find a bow corner or bow corner portion at any stage of the previous step. In all cases where HALCON successfully matches the bow angle or bow angle part, PanCam displays the matching model on the output image.

Referring to fig. 8a, a field of view from a side view image capture device is shown in which a pair of carbon current collectors 42 and 43 of a Y-type pantograph 44 are outlined with respect to a rear screen 45. Fig. 8b is a composite image showing the results of the wear and damage analysis superimposed on the image described above. Yellow contours 46 and 47 highlight those areas of each carbon current collector that have been analyzed for wear. The red outline 48 highlights areas of possible "step" damage. Dark blue contours 49, 50 and 51 show the results of the pantograph model matching. Fig. 8c shows the analysis results.

Referring to fig. 9a, a field of view from a top view of the image capture device is shown in which a Y-type pantograph 52 is shown. Fig. 9b shows a field of view taken from the overhead image capture device, in which the Y-pantograph 52 loses its configuration at the pantograph angle 53. Fig. 9c shows the bow angle damage analysis results presented by the graphical user interface.

Referring to fig. 10, a field of view from a side view image capture device is shown in which a pair of carbon current collectors 54 and 55 of a Y-type pantograph are outlined with respect to a rear screen 56. The results of the damage analysis are superimposed on the image. Blue contours 57, 58 and 59 surround areas of excessive wear. Yellow contours 60 and 61 highlight those areas of each carbon current collector that have been analyzed for wear. The red contours 62, 63, and 64 highlight areas of possible "step" damage. Dark blue contours 65, 66 and 67 show the result of the pantograph model matching.

The operation of a particularly preferred system according to the invention is described in the following paragraphs:

the PanCam program 12 implements a multi-threaded approach. The PanCam program includes threads to handle signals from the locomotive and the pantograph sensors. After receiving the signal from the sensor, the thread adds the sensor input to the queue for processing by the image capture thread. The image capture thread then triggers the appropriate camera 15 or 16 to take an image, as determined by the information provided by USBI/O device 14. When an image has been captured, the image capture thread adds the image it has just captured to the image queue waiting to be processed.

Meanwhile, the AVI tag readers 10 and 11 placed on either side of the track receive locomotive identification information. The tag reader sends the information to the computer 13 on which PanCam is running. This information is transmitted through the serial port as an ASCII character stream that the PanCam software stores in a buffer containing the most recently received tag.

The image processing threads remove images from the image processing queue one at a time and analyze the images. The image processing thread associates each image with a vehicle identification tag whose receive time most closely matches the image capture time. If there is no ID tag with respect to a timestamp within two and a half minutes of image capture (a five minute window), PanCam processes the image without an associated tag.

The image processing thread analyzes the image for signs of damage or wear of the carbon current collector, or for bow angle damage or loss on the pantograph, depending on the location of the image capture device that generated the image. After the analysis is complete, PanCam displays the visible text-based results on the screen and writes the information to the image and text files on the disc. If the diagnostic result indicates possible damage or wear and the user has configured PanCam to do so, PanCam will send an alert to the end user via email and/or SMS. The image processing thread adds email messages to the email queue and PanCam processes these email messages in a separate email sending thread.

In addition to email reports, PanCam can also log results to a central database server via a standard ODBC interface. The central server uses microsoft sqlserver2005expressedition sp2 as a database. On the same server computer, an Apache web server is built with the PHP5 to allow web access to the database. The engineer can then review the results of the analysis via the web interface and make the necessary investigations and repairs on the locomotives and record the results they have considered in the database.

To ensure continued operation of the PanCam in its unsupervised environment, the PanCam program has an internal monitor thread that periodically checks the response of each of the other threads of the PanCam program. If any of these threads become unresponsive for an extended period of time, PanCam restarts the computer. In addition, the PanCam program itself is monitored by an external service that automatically starts PanCam if it detects that the PanCam software is not running or not responding, and can restart the computer running PanCam.

The system account for ensuring interactive use of the desktop does not access network resources. This is the mechanism of the microsoft windows system and cannot be changed. To allow copying of image and data files from a computer running PanCam into a central database server, a second service runs with the PanCam program to perform file copying on its behalf. This copy service runs under a user account with permission to write to the network server file system.

The above embodiments are merely illustrative of the principles of the present invention and various modifications and alterations will readily occur to those skilled in the art. The invention is capable of implementation and implementation in various ways and in other embodiments. It is also to be understood that the terminology employed herein is for the purpose of description and should not be regarded as limiting.

The term "comprises" and variations of the term, such as "comprises" or "comprising," are used herein to indicate that the stated integer(s) is included, but not to exclude any other integer(s), unless an exclusive interpretation of the term is required in the context or use.

Any reference to a publication cited in this specification is not an admission that the publication constitutes prior art.

Claims (37)

1. A system for assessing a state of a pantograph, the system comprising:

a rail-side pantograph monitoring station for capturing images of a pantograph while a locomotive including the pantograph is in normal service, the monitoring station including a first image capture device positioned below the pantograph and at an oblique angle relative to the pantograph;

a station management system for analyzing the images captured at the monitoring station and for determining a state of the pantograph, the station management system configured to:

a) determining a plurality of carbon current collectors in the pantograph by matching the image to a predefined model of a plurality of predefined models representing a plurality of known pantograph types;

b) generating a carbon current collector profile for each of the plurality of carbon current collectors based on the image; and

c) analyzing each carbon current collector profile to determine a status of the pantograph; and

a user interface for controlling the station management system and indicating whether a pantograph is damaged and/or worn.

2. The system of claim 1, wherein the monitoring station comprises:

a data transmission device;

at least one rail side mounted sensor for detecting the locomotive as it enters the monitoring station, referred to as a locomotive sensor;

at least one rail-side mounted sensor for detecting the position of the pantograph at the monitoring station, the sensor being referred to as a pantograph sensor;

at least one image capture device that captures at least one image of the pantograph at the monitoring station; and

a sensor interface that receives input from the sensor and commands the at least one image capture device to capture at least one image of the pantograph at the monitoring station.

3. The system of claim 2, wherein the data transmission device facilitates communication between a sensor, a sensor interface, at least one image capture device, and a station management system.

4. The system of claim 3, wherein the monitoring station further comprises a second image capture device for capturing images of the pantograph, wherein the pantograph includes at least one pantograph angle.

5. The system of claim 4, wherein a first image capture device is configured to capture a contour image of the pantograph, wherein the pantograph comprises at least one carbon current collector, wherein the first image capture device is also referred to as a side position image capture device.

6. The system of claim 5, wherein a second image capture device is positioned above the pantograph at a monitoring station, wherein the second image capture device is also referred to as a top position image capture device.

7. The system of claim 6, wherein the image capture device is a high resolution camera.

8. The system of claim 7, wherein the first image capture device further comprises a back screen.

9. The system of claim 8, wherein the back screen is white.

10. The system of claim 9, wherein the back screen is illuminated.

11. The system of claim 10, wherein the back screen is mounted behind a focal point of the image capture device and within a field of view of the image capture device such that when the first image capture device is activated, the captured image is a contour of the pantograph relative to the back screen.

12. The system of claim 11, wherein the locomotive sensor and/or the pantograph sensor is an infrared sensor.

13. The system as set forth in claim 12, wherein,

wherein the pantograph sensor is a top position pantograph sensor positioned such that it identifies a point of a pantograph within a field of view of a top position image capture device, an

Wherein the monitoring station comprises a further pantograph sensor for detecting the position of the pantograph, the further pantograph sensor being a side position pantograph sensor positioned such that it identifies a point of the pantograph within the field of view of the side position image capture device.

14. The system of claim 13, wherein at least one of the sensors is in communication with at least one of the image capture devices such that the at least one image capture device is activated when a pantograph is detected by the sensor.

15. The system of claim 14, wherein the monitoring station further comprises at least one track side mounted sensor for capturing locomotive identification details, referred to as a locomotive identification sensor.

16. The system of claim 15, wherein the at least one locomotive identification sensor is an automatic vehicle identification tag decoder.

17. The system of claim 16, wherein the automatic vehicle identification tag decoder obtains information relating to any one of: a vehicle identification number of the locomotive at the monitoring station; or a locomotive type.

18. The system of claim 17, wherein the sensor interface has a circuit form, wherein the circuit performs the steps of:

receiving input from the locomotive sensor indicating that the locomotive is at a monitoring station;

receiving input from at least one of the pantograph sensors indicating that a pantograph is within a field of view of one of the image capture devices;

debounce and shape the input received from the sensor; and

when inputs from the locomotive sensor and the pantograph sensor are received simultaneously, a command to obtain an image of the pantograph is provided to at least one of the image capturing devices.

19. The system of claim 18, wherein the sensor interface circuit further performs the steps of: when inputs from the locomotive sensor and the pantograph sensor are received simultaneously, a command to capture locomotive details at the monitoring station is provided to the at least one locomotive identification sensor.

20. A method of analyzing with a computer program whether a pantograph is damaged and/or worn, the method comprising the steps of:

receiving at least one command from a sensor and, upon receipt of the at least one command, activating at least one image capture device to capture an image of the pantograph at a monitoring station, the at least one image capture device being positioned below and at an oblique angle relative to the pantograph;

analyzing the images captured by the at least one image capture device for signs of damage and/or wear, wherein analyzing comprises:

a) determining a plurality of carbon current collectors in the pantograph by matching the image to a predefined model of a plurality of predefined models representing a plurality of known pantograph types;

b) generating a carbon current collector profile for each of the plurality of carbon current collectors based on the image; and

c) analyzing each of the carbon current collector profiles to determine a status of the pantograph; and providing the results of the analysis to an output device.

21. The method of claim 20, wherein the method further performs at least one of:

receiving a user input;

receiving locomotive details from an automatic vehicle identification tag reader and assigning the details to the image of the pantograph;

controlling illumination of a back screen, wherein the back screen is mounted behind a focal point of the at least one image capture device;

calibrating exposure and gain settings of the at least one image capture device;

receiving an input from a user, wherein the input modulates an analysis of the image of the pantograph; and

automatically adjusting an exposure time and a video gain of the at least one image capture device.

22. The method of claim 21, wherein analyzing the images captured by the at least one image capture device comprises:

receiving an input from the at least one image capture device, wherein the input represents an image of a field of view of the at least one image capture device;

calculating coordinates of a pantograph within the input image using the matched predefined model;

extracting at least one image of the area of the pantograph from the input image using the coordinates calculated in the previous step; and

analyzing the at least one image of the area of the pantograph to determine whether the pantograph is damaged and/or worn.

23. The method of claim 22, wherein the region representing the outline of one carbon current collector is extracted from the input image.

24. The method of claim 22, wherein regions representing two carbon current collector outline images are extracted from the input image.

25. The method according to claim 23 or 24, wherein analyzing the at least one image of the area of the pantograph comprises the steps of:

determining a distance between a surface contour line representing a bottom edge of the carbon current collector and a surface contour line representing a top edge of the carbon current collector; and

identifying an area in which the distance measured in the previous step falls below a minimum acceptable distance indicative of wear.

26. The method of claim 25, wherein analyzing the at least one image of the area of the pantograph comprises the steps of:

creating a "rain" pattern in which the area between the bottom of the image and the surface contour line representing the top edge of the carbon current collector is filled with vertical lines;

creating an enclosed area having a circle with a fixed radius on a surface contour line representing a top edge of the carbon current collector; and

the rainfall pattern is subtracted from the enclosed area and the damaged area is identified.

27. The method of claim 26, wherein analyzing the at least one image of the area of the pantograph further comprises:

receiving an input from the at least one image capture device, wherein the input represents an image of a field of view of the at least one image capture device;

matching an image of a pantograph within the input image with a predefined model representing a known pantograph type;

calculating coordinates of a pantograph angle within the input image using the matched predefined model;

damaged or missing pantograph angles are identified by comparing the coordinates identified in the previous step with another predefined model representing a particular pantograph angle design.

28. The method of claim 27, wherein the predefined model is a T-or Y-pantograph configuration.

29. The method of claim 28, wherein the computer is connected to one or more computer networks.

30. The method of claim 29, wherein the output device comprises one or more of: a visual display; a storage device; a relational database; a networking device; or a physical output device.

31. The method of claim 30, wherein the output device further comprises an electronic data transfer device for transferring data to a database running on a computer remote from the station management computer.

32. The method of claim 31, further comprising a user interface comprising a data entry device and an electronic display device.

33. The method of claim 32, wherein the data input device controls tasks performed by the station management system or modulates the manner in which end users view analysis results.

34. The method of claim 33, wherein the user interface is a display on a computer in communication with the station management system and located at a remote site.

35. The method of claim 34, wherein the locomotive is traveling at a speed of no less than 12kph and no more than 80kph during normal service.

36. The method of claim 30, wherein the visual display is a computer monitor, the storage device is a computer hard disk, and the physical output device is paper.

37. An automated method for determining a pantograph state, the method comprising the steps of:

detecting the presence of a locomotive at a monitoring station;

detecting the presence of the pantograph at a monitoring station;

upon simultaneous detection of the locomotive and the pantograph at the monitoring station, activating an image capture device, thereby capturing an image of the pantograph, the image capture device positioned below and at an oblique angle relative to the pantograph;

analyzing an image of a pantograph to determine whether the pantograph is damaged and/or whether a constituent carbon current collector is worn, wherein analyzing comprises a) determining a plurality of carbon current collectors in the pantograph by matching the image to a predefined model of a plurality of predefined models representing a plurality of known pantograph types; b) generating a carbon current collector profile for each of the plurality of carbon current collectors based on the image; and c) analyzing each of the carbon current collector profiles to determine a status of the pantograph; and

reporting the results of the analysis to the end user.