JP2008104312A - Pantograph measurement device by image processing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pantograph measurement device where a pantograph is not lost and data does not lack even if a background such as a tunnel pile opening and a bridge suddenly changes. <P>SOLUTION: In the pantograph measurement device, a video image near the pantograph 3 is acquired from a line sensor 2 installed on a roof of a vehicle 1, the video image is image-processed by an image processing part 6 so as to generate a space-time image, and a position and acceleration of the pantograph 3 are measured. A marker 4 where a region 4b on which light tends to reflect and a region 4a on which light cannot reflect easily make a stripe pattern is installed in the pantograph 3 to cross a scanning direction by the line sensor 2. The image processing part 6 performs pattern matching for scanning a marker pattern corresponding to the stripe pattern in a height direction at every unit time and retrieving a part matched or approximated for not less than a prescribed amount so as to perform collation in the space-time image. Thus, the part can clearly be discriminated from the background at daytime. Even if luminance of the background such as the tunnel pile opening suddenly changes, data can continuously be acquired. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a pantograph measuring apparatus that measures a pantograph by image processing. In particular, the present invention relates to image processing for measuring the height and acceleration of a pantograph.

There is a trolley line as an electric railway facility, but the trolley line must be laid within a specified height from the rail surface. Therefore, it is necessary to manage whether the height of the trolley line is within the control value without being influenced by the secular change and the dynamic factor of the vehicle.
At this time, since the height of the trolley line is equivalent to the height of the pantograph, the height of the pantograph is managed instead. A pantograph is one of the current collectors installed on the roof of an electric railway vehicle. Further, when the pantograph vibrates downward at a large acceleration during operation, the panda and the trolley wire are separated from each other, and the trolley wire is locally worn by this arc. Therefore, it is necessary to manage so that the acceleration of the pantograph becomes small.

As a pantograph measurement means, there are dedicated measurement vehicles called inspection vehicles, vehicle limit measurement vehicles, and the like, which are operated at regular intervals by sewing between commercial operations.
Many sensors for measuring the inclination of the vehicle body, the deviation of the rail, and the like are attached to these measurement vehicles, and one of the sensors is a pantograph measurement sensor (Non-Patent Document 1).
The pantograph measurement method includes a laser sensor method, a light cutting sensor method, an acceleration sensor method, and an image processing method, and has the following characteristics.

1) The laser sensor is a sensor that mainly uses a scanning method, and scans the pantograph with a mirror or the like, and measures the distance to the pantograph by the positional difference of the reflected wave and the deformation of the irradiated laser shape. is there.
2) The light-cutting sensor is a sensor that projects the fringes onto the measurement object, receives the fringes that are uneven according to the pantograph shape, and measures the distance to the pantograph.
3) An acceleration sensor is a sensor that outputs acceleration by a gyroscope or a piezoelectric element, and is a sensor that is directly attached to a pantograph and measures the acceleration of the pantograph.
4) As an image processing method, there is a method of detecting a pantograph by model matching or pattern matching.

However, these methods also have the following problems.
(1) The scanning period of the laser sensor is relatively slow in order to limit the rotational speed of the motor that rotates the mirror and to prevent resonance of the mirror. As a result, the laser sensor can measure the position (low frequency component) of the pantograph, but there is a problem that is not suitable for measuring acceleration (high frequency component).
(2) The light cutting sensor cannot measure in the daytime. This makes it impossible to measure during the daytime when the thermal expansion is severe.
(3) The method of measuring the acceleration of a pantograph with an acceleration sensor is a method mainly used at present.

However, the following measures are necessary and it is not a simple measurement method.
(A) It is necessary to fix the sensor directly to the pantograph.
(A) It is necessary to consider noise resistance for the cable for extracting the sensor output voltage.
(C) It is necessary to consider insulation for the cable from which the sensor output voltage is extracted.

(4) The image processing method has a problem that the calculation processing becomes enormous when the measurement time is long or the number of frame rates per unit time is large.
On the other hand, in order to solve the above-described problems, Patent Document 1 acquires a video near a pantograph from a line sensor installed on the roof of a vehicle, generates a space-time image from the video, The averaging process is repeated to obtain a hierarchical space-time image, and the position and acceleration of the pantograph are measured from the hierarchical space-time image.
However, with this method, the pantograph may be temporarily lost due to a sudden change in the background, such as under a tunnel pit or overpass, and data loss may occur.
Japanese Patent Application Laid-Open No. 2002-279409 “Pantograph Measurement Method Using Image Processing and Measurement Apparatus Using This Method” By the Institute of Electrical Engineers of Japan, “Modernization technology for maintenance of train track facilities”

  The pantograph measurement method includes a laser sensor method, a light cutting sensor method, an acceleration sensor method, an image processing method, and a measurement method by image processing using the line sensor disclosed in Patent Document 1, and has the following problems.

(1) The scanning cycle of the laser sensor is relatively slow in order to limit the rotational speed of the motor that rotates the mirror and to prevent resonance of the mirror.
As a result, the laser sensor can measure the position (low frequency component) of the pantograph, but there is a problem that is not suitable for measuring acceleration (high frequency component).
(2) The light cutting sensor cannot measure in the daytime. This makes it impossible to measure during the daytime when the thermal expansion is severe.
(3) The method of measuring the acceleration of a pantograph with an acceleration sensor is a method mainly used at present.

However, it is necessary to fix the sensor directly to the pantograph, it is necessary to consider noise resistance for the cable that takes out the sensor output voltage, it is necessary to consider insulation for the cable that takes out the sensor output voltage, It is not a simple measurement method.
(4) The image processing method has a problem that the calculation processing becomes enormous when the measurement time is long or the number of frame rates per unit time is large.
(5) In the case of the measurement method by image processing using the line sensor of Patent Document 1, there is a problem that the pantograph is temporarily lost due to a sudden change in the background such as a tunnel pit or under the overpass and data loss occurs.

  The pantograph measuring apparatus according to claim 1 of the present invention that solves the above-mentioned problem obtains a video near the pantograph from a line sensor installed on the roof of the vehicle, and performs image processing on the video by an image processing unit to obtain a space-time image. In the pantograph measuring device that generates and measures the position and acceleration of the pantograph, the pantograph includes a marker in which a region where light is easily reflected and a region where light is difficult to reflect is striped in the scanning direction of the line sensor. It is characterized by being installed across the road.

  The pantograph measuring apparatus according to claim 2 of the present invention that solves the above-described problem is the pantograph measuring apparatus according to claim 1, wherein the image processing unit includes a marker pattern corresponding to the striped pattern in the space-time image in a height direction for each unit time. Pattern matching is performed by searching for a portion that matches or approximates to a certain level or more.

  The pantograph measuring apparatus according to claim 3 of the present invention for solving the above-mentioned problems is characterized in that, in claim 1 or 2, the line sensor scans an oblique line with respect to the pantograph to acquire an image. To do.

  A pantograph measuring apparatus according to a fourth aspect of the present invention for solving the above-mentioned problems is the pantograph measuring apparatus according to the first or second aspect, wherein an area camera is used instead of the line sensor, and the horizontal average value obtained by the area camera is used. A space-time image is obtained.

The present invention has the following effects.
(I) Since it is a non-contact method, it can be operated even at high speeds.
(Ii) There is no need to consider collisions with existing structures such as points, air sections and anchors due to the structure of the device.
(Iii) There is no need to use special lighting.

(Iv) Compared with the method using laser light, it is not necessary to consider the influence on the human body, and handling is simple.
(V) Compared to the method using laser light, there is no trouble of precise alignment between the light source and the light receiving device.
(Vi) The marker attached to the pantograph has a striped pattern in which light is easily reflected and light is not easily reflected, so it can be clearly separated from the background even in the daytime. Data can be continuously acquired even when the brightness of the abruptly changes.

(Vii) By performing pattern matching on the space-time image, the influence of noise can be eliminated and the marker image can be searched reliably.
(Viii) Further, the resolution can be improved in accordance with the inclination by scanning the line sensor with an oblique line with respect to the pantograph.
(Ix) Furthermore, using an area camera instead of the line sensor and using the average of the horizontal direction of a planar image has an advantage of noise removal.
(X) By complicating the shape of the marker attached to the pantograph, the feature amount is increased, the search performance is improved, and erroneous detection can be prevented.

   The form shown as an example below is the best form for carrying out the present invention.

(1) Example 1 (basic concept)
The object of the present invention is to easily measure the height and acceleration of a pantograph by image processing, and this embodiment is based on the basic concept.
As shown in FIG. 1 (a), the line sensor 2 is installed on the roof of the vehicle 1, and the image of the marker 4 attached to the hull of the pantograph 3 is acquired.

Here, the scanning direction of the line sensor 2 is a direction in which the pantograph 3 and the marker 4 are cut vertically. As a result, the marker 4 can always be imaged regardless of the height of the pantograph 3.
As shown in FIG. 1B, the marker 4 is of a color or material that hardly reflects light (hereinafter referred to as a black marker) 4a and has a color or material that easily reflects light (hereinafter referred to as a white marker). Say) 4b is sandwiched to form a striped pattern. Further, as the illumination 5, normal illumination is used.

Further, the image acquired by the line sensor 2 is subjected to image processing by the image processing unit 6, and the measured pantograph height and acceleration are recorded in the result recording unit 7 as a result of the image processing.
The image processing method in the image processing unit 6 is processed as follows according to the flowchart shown in FIG.

(1) Generation of Space-Time Image First, as shown in FIG. 2, a video of the marker 4 attached to the pantograph 3 is acquired by the line sensor 2 every unit time (every frame rate), and the space-time image shown in FIG. 3 is generated. .
The space-time image shown in FIG. 3 has the vertical axis as the height position and the horizontal axis as the time, and corresponds to the stripe pattern of the marker 4, and the black band A with little light reflection, the light reflection is A striped pattern in which a large white band B is sandwiched is continuous.
In addition, the background of the pantograph such as a train line facility crossing the pantograph near at high speed appears as noise C.

(2) Pattern Matching When the size of the marker 4 and the direction of the line sensor 2 are taken into consideration, the size of the image of the marker 4 that appears in the position direction on the image is almost fixed.
Therefore, as shown in FIG. 4, a marker pattern corresponding to the stripe pattern and position of the marker 4 is generated. As shown in FIG. 4, the marker pattern has a luminance distribution according to the position of the marker on the image, and a plurality of marker patterns are prepared that change according to the height position indicated by the arrow in the figure.
Then, as shown in FIG. 5, the marker pattern is scanned from the upper side to the lower side every unit time to search for a location that matches the marker pattern. When a matching part cannot be found, a plurality of patterns that are approximated by a certain level are recorded with a ranking from the most approximated part of the scanning line. That is, a plurality of records such as the first candidate and the second candidate are recorded.
Also, if there is no approximate location, it is suspended.

(3) Panda Position Interpolation Subsequently, in the pattern matching, the reserved position D and the unconnected position E as shown in FIG. As an interpolation method, there is simply a method of linearly complementing so as to fill a gap at the reserved portion, but it may be complemented by other methods.

(4) Processing end determination For all the space-time images, the pattern matching and position interpolation processes are repeated as described above, and the pantograph position is recorded.

(5) Height output The recorded pantograph position is output as a height.

(6) Acceleration output At the recorded pantograph position, the extreme value of the inflection point protruding downward is obtained, and an extreme value equal to or greater than a predetermined value is output as acceleration.

In this embodiment, the pantograph height and acceleration are measured by image processing, and since it is a non-contact method, it can be operated at high speed.
In addition, the line sensor 2 can be installed at a position away from existing structures such as a point, an air section, and an anchor on the structure of the apparatus that the image processing unit 6 performs image processing on the video acquired by the line sensor 2 on the vehicle 1 Therefore, it is not necessary to consider a collision with an existing structure, and basically line sensor images can be taken in all sections.

Further, it is not necessary to use laser light as special illumination, and there is no difficulty in handling in consideration of the influence on the human body as compared with the case of using laser light. Furthermore, there is no trouble of performing precise alignment between the light source and the light receiving device.
The stripe pattern of the marker 4 attached to the pantograph 3 can be measured by searching for the pattern even in the daytime because the black marker 4a separates the background (such as the sky) and the white marker 4b.

  Further, even if the background suddenly changes, such as in a tunnel well as shown in FIG. 7, the black marker 4A is the same as the background, but the white marker 4B reflects the light of the projector (illumination), so data is not lost. Continuous measurement is possible.

(2) Example 2 (Space-time image generation by oblique lines)
In the present embodiment, as shown in FIG. 8, the line sensor 12 scans the boat body of the pantograph 3 with an oblique line.
That is, the line of the line sensor 12 may not be in the optimum measurement range for the pantograph 3 to be measured due to restrictions on the camera mounting position and lens magnification.

Therefore, the line sensor 12 according to the present embodiment acquires an image by scanning the pantograph 3 with a line inclined by θ degrees from the vertical direction. Thereby, there is a merit of improving the resolution of the pantograph 3 in the height direction by 1 / COSθ.
The marker 14 installed on the pantograph 3 is longer than that of the first embodiment so that the line sensor 12 always captures an image even when the pantograph 3 moves up and down.
In this embodiment, the rest is the same as that of the first embodiment described above, and the same effects are obtained.

(3) Example 3 (complication of marker shape)
In this embodiment, as shown in FIG. 9, the marker 24 attached to the pantograph 3 has a complicated striped pattern. That is, the white marker 24b has two or more lines and the black marker 24a has three or more lines.
Thereby, the feature amount at the time of pattern matching is increased, search performance is further improved, and erroneous detection can be prevented.
In this embodiment, the rest is the same as that of the first embodiment described above, and the same effects are obtained.

(4) Example 4 (area camera)
In this embodiment, an area camera is used instead of the line sensor 2 as shown in FIG.
The method for generating the space-time image of this embodiment is as follows.
(I) First, as shown in FIG. 10, an image near the pantograph is acquired by the area camera every unit time, and the rectangular area G including the pantograph 3 is cut out in the acquired area camera imaging range F. The rectangular area G is an area that is long in the vertical direction and short in the horizontal direction. There are two rectangular areas G on the left and right.
(Ii) Next, in the rectangular region G, the luminance is averaged in the horizontal direction to obtain an average value, and the average value is made one line (scanning line) in the upper and lower sides.
(Iii) Subsequently, the acquired line is generated into a space-time image as shown in FIG.

In FIG. 10, two rectangular areas G are set. However, it is preferable to set a plurality of areas more than that and generate a spatio-temporal image with an average value in all the horizontal directions in the plurality of areas.
In the present embodiment, since a space-time image is generated from the average of the planar rectangular area G, items other than the pantograph such as a train line facility that traverses the vicinity of the pantograph at a high speed disappear, so that noise removal is effective.
In this embodiment, the rest is the same as that of the first embodiment described above, and the same effects are obtained.

  The present invention is applicable to a pantograph measuring apparatus that measures a pantograph by image processing.

FIG. 1A is a schematic view of a pantograph measuring apparatus according to the basic concept (Example 1) of the present invention, and FIG. 1B is an enlarged view of a dashed line portion in FIG. . It is a flowchart which shows the pantograph measuring method which concerns on the fundamental view (Example 1) of this invention. It is a graph which shows the example of a space-time image. It is a graph which shows the example of search pattern generation. It is a graph which shows the pattern matching with respect to a space-time image. It is a graph which shows interpolation of a pantograph position. It is a graph which shows the example of imaging in a tunnel wellhead. It is the schematic of the pantograph measuring apparatus which concerns on Example 2 of this invention. FIG. 9A is a perspective view of a pantograph provided with a complicated marker according to Example 3 of the present invention, and FIG. 9B is an enlarged view of a one-dot chain line portion in FIG. 9A. It is the schematic which shows the pantograph vicinity imaged by the area camera which concerns on Example 4 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vehicle 2,12 Line sensor 3 Pantograph 4, 14, 24 Marker 4a, 24a Black marker 4b, 24b White marker 5 Illumination 6 Image processing part 7 Recording device A Black belt B White belt C Noise D Reserving part E It connects Position that is not F Area camera imaging range G Rectangular area

Claims (4)

  In the pantograph measurement device that acquires a video near a pantograph from a line sensor installed on the roof of the vehicle, generates a space-time image by performing image processing on the video by an image processing unit, and measures the position and acceleration of the pantograph, In the pantograph, a pantograph measuring device is characterized in that a marker in which a region where light is easily reflected and a region where light is difficult to be reflected is arranged so as to cross a scanning direction by the line sensor.   The image processing unit performs pattern matching for collating the space-time image by scanning a marker pattern corresponding to the striped pattern in the height direction every unit time and searching for a location that matches or approximates a certain level. The pantograph measuring apparatus according to claim 1.   The pantograph measurement apparatus according to claim 1, wherein the line sensor acquires an image by scanning an oblique line with respect to the pantograph.   3. The pantograph measurement apparatus according to claim 1, wherein an area camera is used instead of the line sensor, and a space-time image is obtained from an average value in a horizontal direction acquired by the area camera.