JP4258340B2 - Pantograph detection device - Google Patents

Description

  The present invention relates to a technique for detecting a pantograph by image processing from an image of an ITV camera installed on a train so that the pantograph is reflected.

In a technique for detecting a pantograph by image processing (see Patent Document 1, Japanese Patent Application No. 2002-151840), pantograph detection is detected from a pattern match between a video and a pantograph pattern registered in advance (see Patent Document 2). ).
In such a technique, when the camera is installed in front of the pantograph, the pantograph can be detected by pattern matching of one pantograph model.
JP-A-2002-139305 (Japanese Patent Application No. 2000-332841 “Pantograph Obstacle Detection Method and Device”) Japanese Patent Application Laid-Open No. 7-271979 (Japanese Patent Application No. 6-57924 "Image Recognition Method and Apparatus")

However, in the background art described above, when the camera 2 is installed obliquely with respect to the pantograph 1 as shown in the overall view of FIG. 1, the appearance (aspect) of the pantograph 1 changes with the height of the pantograph 1. As a result, the geometrical change is made on the image as shown in FIG.
Thereby, in the pattern match using one pantograph model, there exists a problem of detecting the position which shifted | deviated with the height change of the pantograph.
In order to solve this problem, projection conversion is performed so that the pantograph looks the same, and positional deviation is eliminated. However, projection conversion has a problem that it takes processing time.

  In the pantograph detection device by image processing according to claim 1 of the present invention for solving the above-described problem, a camera is installed obliquely with respect to a pantograph that moves up and down, and an image captured by the camera is processed by image processing. In the apparatus for measuring the position of the pantograph, a linear locus in which the center point of the pantograph moves on the image as the pantograph moves up and down is obtained in advance, and when the center point of the pantograph is obtained from the input image, the input image The center point of the pantograph is obtained by correcting the center point of the pantograph obtained by directly recognizing the pantograph so as to be on the straight line locus.

The pantograph detection device by image processing according to claim 2 of the present invention for solving the above-mentioned problem is that a camera is installed obliquely with respect to a pantograph that moves up and down, and an image photographed by the camera is processed by image processing. In the apparatus for measuring the position of the pantograph, a linear locus in which the center point of the pantograph moves on the image as the pantograph moves is obtained in advance, and the linear locus is obtained when obtaining the center point of the pantograph from the input image. The center point of the pantograph is obtained by recognizing the image along the line.

  According to a third aspect of the present invention, there is provided a device for detecting a pantograph by image processing, wherein a camera is installed obliquely with respect to a pantograph moving up and down, and an image photographed by the camera is processed by image processing. In the apparatus for measuring the position of the pantograph, the center point of the pantograph and the other two recognition target points are set in advance, and the respective linear trajectories on the images of the two recognition target points as the pantograph moves up and down are obtained. The intersection of these linear trajectories is obtained, the third straight line connecting the intersection and the center point of the pantograph is obtained, and when the center point of the pantograph is obtained from the input image, the input image is directly recognized and obtained. The center point of the pantograph is obtained by correcting the center point of the pantograph so as to be on the third straight line.

According to a fourth aspect of the present invention, there is provided a device for detecting a pantograph by image processing, wherein a camera is installed obliquely with respect to a pantograph that moves up and down, and an image captured by the camera is subjected to image processing. The center point of the pantograph and the other two recognition target points are set in advance, and a small region including each of the recognition target points is registered as a recognition target image. The relationship between the center points of the pantograph is calculated and stored in advance, the respective linear trajectories with respect to the recognition target points accompanying the movement of the pantograph are calculated in advance, and when the position of the pantograph is recognized from the input image, The position of the recognition target point is obtained by performing image recognition on the small region along the recognition, and the recognition obtained in advance Based on the positional relationship between the elephant point and the center point of the pantograph, and obtains the center point of the pantograph of the input image.

  According to a fifth aspect of the present invention, there is provided an apparatus for detecting a pantograph by image processing, wherein a camera is installed obliquely with respect to a pantograph moving up and down, and an image photographed by the camera is subjected to image processing. The center point of the pantograph and the other two recognition target points are set in advance, and a small region including each of the recognition target points is registered as a recognition target image. Pre-calculate and store the relationship between the center points of the pantograph, recognize the input image to obtain the center point of the pantograph, and the small region at a position based on the pre-calculated positional relationship between the recognition target point and the center point of the pantograph The recognition target point is obtained by performing image recognition on the image, and the center point of the pantograph is corrected from the position of the obtained recognition target point. And wherein the Rukoto.

According to a sixth aspect of the present invention, there is provided a device for detecting a pantograph by image processing, wherein a camera is installed obliquely with respect to a pantograph that moves up and down, and an image photographed by the camera is subjected to image processing. The center point of the pantograph and the other two recognition target points are set in advance, and a small region including each of the recognition target points is registered as a recognition target image. calculated beforehand stores a relation between the center point of the pantograph, in recognizing a position of the pantograph from the input image, by performing image recognition on the small area, it obtains the recognition target point, the recognition target in advance calculated By performing image recognition by constraining the vicinity of the pantograph center point based on the positional relationship between the point and the center point of the pantograph, And it obtains the center point of the serial pantograph.

  In the pantograph detection device according to the first aspect, the center of the pantograph that moves up and down is used as a straight line locus, and the center of the pantograph in the image is corrected by the pattern match from the two points where the center of the pantograph moves up and down. There is an advantage that the center point of the pantograph can be detected, and there is an advantage that the center can be corrected at high speed by a simple expression obtained from two points.

  In the pantograph detection device according to claim 2, using the feature that the center of the moving pantograph becomes a linear locus, pattern matching of a small region is performed along the vicinity of the linear locus in the image, and the center of the pantograph is obtained. There is an advantage that the center of the pantograph can be obtained at high speed because pattern matching is performed within a search range in which one small region is constrained.

  In the pantograph detection device according to the third aspect, the pantograph that moves up and down is used as a straight line locus, and the position of the pantograph that is shifted by the pattern match is corrected by predetermined five points of the pantograph. In addition, there is an advantage that the pantograph position can be corrected at high speed by a simple formula.

  In the pantograph detection device according to the fourth aspect of the present invention, the moving pantograph uses a feature that becomes a linear locus on the image, and the position of the pantograph is obtained from predetermined five points of the pantograph, and two small regions are constrained. Since pattern matching is performed in the search range, there is an advantage that the position of the pantograph can be obtained at high speed.

  The pantograph detection apparatus according to claim 5 uses the presence of a characteristic shape on the pantograph, and corrects the detection position of the pantograph shifted by the pattern match by a pattern match of a small region including the characteristic shape. In addition, since correction is performed using a pattern match result with a small area and a limited search range, there is an advantage that position correction can be performed at high speed.

  The pantograph detection apparatus according to claim 6 utilizes the presence of a characteristic shape on the pantograph, detects the pantograph with a pattern match, and reconfirms with a pattern match of a model that includes the pantograph like a dotted frame. Since it is reconfirmed by pattern matching, there is an advantage that the reliability of the detection result is improved.

  In the present invention, Examples 1 to 6 shown below are the best modes.

FIG. 1 shows a pantograph detection apparatus according to the first embodiment of the present invention (pantograph center correction from two points).
As shown in FIG. 1, a camera 2 is installed obliquely with respect to the pantograph 1, and an image photographed by the camera 2 is taken into the pantograph detection device 3.

The pantograph detection device 3 uses the feature that the center of the pantograph 1 that moves up and down is a straight locus as indicated by a one-dot chain line L in FIG. Image processing is performed to correct the center coordinates of the pantograph that are shifted by the match.
The pantograph detection device may be configured in hardware, but may be configured in software by causing a computer to read a program for executing image processing.
Image processing by the pantograph detection device 3 will be described with reference to the flowchart shown in FIG.

First, an area A including a pantograph as shown in the dotted frame in FIG. 2 is registered as model data for model matching (step S1).
Next, as shown in FIG. 2, the center points P ₁ and P ₂ of the pantograph 1 at positions moved up and down in advance are indicated and registered on the screen, and a straight line L is obtained by a program in the apparatus (step S2). ).
The center point P ₁ is the center of the pantograph 1 when positioned upward, and the center point P ₂ is the point when the center point P ₁ is positioned downward. The center points P ₁ and P ₂ are preferably present at the upper and lower edges of the image for accuracy.
The above steps S1 and S2 are preprocessed in advance.

Each time an image is input from the camera 2 (step S3), the center point (x, y) of the pantograph is detected by pattern matching between the model of the dotted line frame in FIG. 2 and the input image (step S4).
), X is corrected so that the center point of the obtained pantograph is on the straight line L, and (x ′, y) is obtained (step S6). If the pattern match fails (step S5), steps S3 and S4 are repeated.
The above steps S3 to S6 are repeated for each image input until the end of the image (step S7).

As described above, this embodiment has an advantage that the center of the pantograph can be corrected at high speed.
That is, when the camera 2 and the pantograph 1 are installed obliquely as in the general view shown in FIG. 1, the conventional technique needs to perform projection conversion by the number of pixels of the image and correct the geometric change due to the vertical movement of the pantograph. was there.
However, this embodiment has an advantage that the position can be corrected at high speed by the straight line L obtained from two points where the center of the pantograph 1 is moved up and down.

  The present embodiment (obtains a center on a pattern match of a small area on two points) uses the feature that the center of the pantograph 1 that moves up and down becomes a locus of a straight line L as shown by a one-dot chain line L in FIG. The pattern matching of small areas is performed along the vicinity of the straight line L in the image, and the center of the pantograph is obtained. As shown in FIG. 3, the “small region” refers to a hatched region in which the straight line L is expanded laterally.

Details of the image processing according to the present embodiment are shown in the flowchart of FIG.
First, as shown in FIG. 3, the pantograph center point _Pc and the small area B of the dotted frame around it are registered as models (step T1).
Next, the two points (P ₁ , P ₂ ) in FIG. 3 are registered, and a straight line L connecting the points P ₁ and P ₂ is obtained (step T2).
The point P ₁ is the center of the pantograph when the pantograph is positioned upward, and the point P ₂ is the point when the point P ₁ is positioned downward. It is desirable that the points P ₁ and P ₂ exist at the upper and lower edges of the image for accuracy.
The above steps T1 and T2 are preprocessed in advance.
Then, for each image input (step T3), the center point (x, y) of the pantograph is detected by pattern matching between the model B of the dotted line frame in FIG. 3 and the input image (step T4).
Subsequently, x is corrected so that the center point (x, y) of the obtained pantograph is on the straight line L to obtain (x ′, y) (step T6).
If the pattern match fails (step T5), steps T3 and T4 are repeated.
The above steps T3 to T6 are repeated for each image input until the end of the image (step T7).

As described above, this embodiment has an advantage that the center of the pantograph can be obtained at high speed.
That is, when the camera 2 and the pantograph 1 are in the positional relationship of the overall view shown in FIG. 1, when the pantograph model is registered as in the dotted frame in FIG. 2, there is a problem that the pattern match of the straight line L is shifted.
In contrast, the present embodiment has an advantage that the center of the pantograph can be obtained at high speed because the pattern matching is performed in the search range in which one small region is constrained.
Further, in the present embodiment, as shown in FIG. 3, since a small region indicated by a diagonal line obtained by horizontally expanding the straight line L is pattern-matched as a search range, the matching allows a horizontal displacement of the pantograph. Corresponds to horizontal movement.

  In this embodiment (pantograph position correction from 5 points), as indicated by the one-dot broken line in FIG. 4, the pantograph that moves up and down makes use of the feature that the trajectory is a straight line. This is to correct the position of the pantograph that deviates.

Details of the image processing according to the present embodiment are shown in the flowchart of FIG.
First, an area including a pantograph as shown by a dotted frame in FIG. 4 is registered as a model A (step U1).
Next, five points in FIG. _{4 (P l, P 2,} P 3, P 4, P 5) to register (step U2). Here, a straight line L ₁ connecting the points P ₁ and P ₄ and a straight line L ₂ connecting the points P ₂ and P ₃ are obtained, and a straight line L connecting the intersection P ₆ and the point P ₅ of these straight lines L ₁ and L ₂ is obtained. ₃ Find (ax + by + c = 0). In addition, the actual coordinates (W ₁ , W ₂ , W ₃ , W ₄ ) [mm] in the coordinates of (P ₁ , P ₂ , P ₃ , P ₄ ) [pix] are acquired, and the matrix of Expression (1) is obtained. Find M.
Points P ₁ and P ₂ are points on the pantograph when the pantograph is positioned upward, and points P ₃ and P ₄ are points where the points P ₁ and P ₂ have moved downward. Point P ₅ is the center of the pantograph. The points P ₁ , P ₂ , P ₃ , and P ₄ are preferably present at the four corners of the image for accuracy, and the point P ₅ is desirably present at the lower side.
The above steps U1 and U2 are preprocessed in advance.

Then, for each image input (step U3), the center point (x, y) of the pantograph is detected by pattern matching between the model of the dotted frame in FIG. 4 and the input image (step U4), and the y-coordinate of this center point and the straight line L _3. Obtain the corrected x ′ in ₃ and use the formula (1) and (x ′, y) to calculate the center point of the pantograph [mm
] The coordinates are obtained (step U6). If the pattern match fails (step U5), steps U3 and U4 are repeated.
The above steps U3 to U6 are repeated for every image input until the end of the image (step U7).

As described above, this embodiment has an advantage that the position can be corrected at high speed.
That is, when the camera 2 and the pantograph 1 are in the positional relationship of the general view shown in FIG. 1, it is necessary to perform projection conversion by the number of pixels of the image and to correct the shift due to the geometric change of the pantograph.
This embodiment has an advantage that the position can be corrected at high speed using a simple formula obtained from predetermined five points.

In the present embodiment (position acquisition by pattern matching of 5 points and a small area), as shown by the straight lines L ₁ and L ₂ in FIG. 5, the pantograph 1 that moves up and down uses a feature that becomes a linear locus on the image. The position of the pantograph is obtained from the predetermined five points of the pantograph 1.

Details of the image processing according to the present embodiment are shown in the flowchart of FIG.
First, as shown in FIG. 5, the pantograph center point P _c , the feature points P _L and P _R on the pantograph, and small areas in the vicinity thereof are registered as indicated by the dotted frame (step V1).
Further, relative positions V _L = P _c −P _L and V _R = P _R −P _c from the pantograph center point P _c to the feature points P _L and P _R are obtained. Further, four points (P ₁ , P ₂ , P ₃ , P ₄ ) are registered (step V2). In addition, the actual coordinates (W ₁ , W ₂ , W ₃ , W ₄ ) [mm] in the coordinates of (P ₁ , P ₂ , P ₃ , P ₄ ) [pix] are acquired, and the matrix of Expression (1) is obtained. Find M. Here, a straight line L ₁ connecting the points P ₁ and P ₄ is obtained, and a straight line L ₂ connecting the points P ₂ and P ₃ is obtained.
Points P ₁ and P ₂ are points when the characteristic points P _L and P _R on the pantograph are located above, and points P ₃ and P ₄ are points where the points P _L and P _R have moved downward. The points P ₁ , P ₂ , P ₃ , and P ₄ are preferably present at the four corners of the image for accuracy.
The above steps V1 and V2 are preprocessed in advance.

Then, for each image input (step V3), the search range is constrained along the vicinity of the straight lines L ₁ and L ₂ to match the pattern of the small area and the input image, and the points P ′ _FL and P ′ _FR as shown in FIG. Get. A point internally divided into a ratio of | V _L |: | V _R | on the straight line connecting the points P ′ _FL and P ′ _FR is taken as a detection result as a pantograph center point P ′ _FC (step V4). The center point [mm] coordinate of the pantograph is obtained by the equation (1) and P ′ _FC = (x, y). If the pattern match fails (Step V
5) Steps V3 and V4 are repeated.
The above steps V3 to V5 are repeated for each image input until the end of the image (step V7).

As described above, this embodiment has an advantage that the position of the pantograph can be obtained at high speed.
That is, when the camera 2 and the pantograph 1 are in the positional relationship of FIG. 1 as a whole, when a pantograph model is registered as shown by the dotted frame in FIG. 4, there is a problem that the pattern match is shifted as the pantograph moves up and down.
In the present embodiment, the position of the pantograph is obtained from the pattern match of the small area in which the search range is constrained on the straight lines L ₁ and L ₂ .
Furthermore, in the present embodiment, since a small area obtained by horizontally expanding the straight lines L ₁ and L ₂ is subjected to pattern matching as a search range, matching allows a horizontal shift of the pantograph, and therefore corresponds to a horizontal movement of the pantograph. .

  This embodiment (correcting the pantograph position by pattern matching of two small areas) utilizes the presence of a characteristic shape on the pantograph as shown by rectangular small areas 1 and 2 in FIG. The detection position of a pantograph that is shifted by a simple pattern match of the dotted line frame model shown in FIG. 5 is corrected by a pattern match of a small region that includes a characteristic shape.

Details of the image processing according to the present embodiment are shown in the flowchart of FIG.
First, a region including a pantograph as a dotted line frame in FIG. 6 is registered as a model A, and a center point P _{C of the} pantograph is registered (step X1).
Next, the feature point P _L on the pantograph registers the P _R, P _L, small region 1 as shown a region near the P _R in solid lines, to register as a small region 2 (step X2). Here, relative positions V _L = P _C −P _L and V _R = P _R −P _C from the center point P _C of the pantograph to the feature points P _L and P _R are obtained. In FIG. 6, the end of the pantograph boat is used as the feature point, but the end point of the horn or the like may be set as the feature point.
The above steps X1 and X2 are preprocessed in advance.

Then, each image input (step X3), in the pattern matching with the model A to cover the input image and the pantograph, detects the position P _FC shifted from pantograph center as shown in FIG. 7 (step X4). If the pattern match fails (step X5), steps X3 and X4 are repeated.
Further, the search range is constrained to the vicinity of the relative positions P _FL and P _PR moved from P _FC to V _L and V _R , pattern matching of two regions is performed, and points P ′ _FL and P ′ _PR are obtained (step X6). .
A point that is internally divided into a ratio of | V _L |: | V _R | on the straight line connecting the points P ′ _FL and P ′ _PR is corrected as a pantograph center point P ′ _FC (step X8).
If the pattern matching of the two areas fails, the positions P _FC , P _PL , and P _FR are set as pantograph positions (step X9).
The above steps X3 to X8 are repeated for each image input until the end of the image.

As described above, as a first advantage of this embodiment, there is an advantage that the position can be corrected at high speed.
That is, according to the conventional technique, it is necessary to perform projection conversion by the number of pixels of the image to correct a shift due to a geometric change of the pantograph.
On the other hand, in the present embodiment, since correction is performed using a pattern match result that is a small region and the search range is restricted, there is an advantage that position correction can be performed at high speed.
As a second advantage, the first and third embodiments described above cannot cope with the case where the pantograph moves in the horizontal direction, but this embodiment has an advantage that the position can be corrected even if the pantograph moves in the horizontal direction.

  This embodiment (reconfirmation after pattern matching of two small areas) utilizes the presence of a characteristic shape on the pantograph as shown by rectangular small areas 1 and 2 in FIG. After the feature point is detected by pattern matching in a small area of the frame, it is reconfirmed by pattern matching of the model A including the pantograph as shown by the dotted frame.

Details of the image processing according to the present embodiment are shown in the flowchart of FIG.
First, an area including a pantograph as a dotted line frame in FIG. 6 is registered as a model A, and a center point P _{C of the} pantograph is registered (step Y1).
Next, the feature point P _L on the pantograph registers the P _R, P _L, small region 1 as shown in the vicinity small area of P _R in solid lines, to register as a small region 2 (step Y2). Here, relative positions V _L = P _c −P _L and V _R = P _R −P _C from the center point P _c of the pantograph to the feature points P _L and P _R are obtained.
In FIG. 6, the end of the pantograph boat is used as the feature point, but the end point of the horn or the like may be set as the feature point.
The above steps Y1 and Y2 are preprocessed in advance.

Then, for each image input (step Y3), feature points P ′ _FL and P ′ _PR are obtained as shown in FIG. 7 by pattern matching between the input image and the small areas 1 and 2 (step Y4). If the pattern match fails (step Y5), steps Y3 and Y4 are repeated.
Subsequently, in the model A including the pantograph, the search range is constrained to the vicinity of the point P ′ _FC which is internally divided into the ratio of | V _L |: | V _R | on the straight line connecting the feature points P ′ _FL and P ′ _PR. Pattern matching is performed to obtain the point P ′ _FC (step Y5).
When a plurality of feature points P ′ _FL and P ′ _FR are obtained, pattern matching is performed using a model including a pantograph for each of the plurality of combinations (step Y6). If the pattern match fails (step Y7), steps Y3 to Y6 are repeated.
The above steps Y3 to Y7 are repeated for each image input until the end of the image.

  As described above, the present embodiment has an advantage that the reliability of the detection result is improved because the pattern match is performed using a model including the entire pantograph and the detection result is reconfirmed.

  The position of the pantograph detected by the present invention is used for equipment maintenance depending on whether or not it is at a specified position.

1 is an overall view of a pantograph detection device according to an embodiment of the present invention. It is explanatory drawing which shows the area | region A which includes the linear locus | trajectory of a pantograph center point on a screen, and a pantograph. It is explanatory drawing which shows the linear locus | trajectory of the pantograph center point on a screen, and the small area | region along this linear area | region. It is explanatory drawing which shows the area | region A which includes five points of the pantograph on a screen, the straight line which connects them, and a pantograph. It is explanatory drawing which shows the small area | region which covers 5 points | pieces of a pantograph on a screen, and two feature points. It is explanatory drawing which shows the small area | regions 1 and 2 which include the area | region which includes the pantograph on a screen, and two feature points. It is explanatory drawing which shows the relative relationship of the center point of a pantograph on a screen, and two feature points. It is a flowchart which shows the image process by the pantograph detection apparatus which concerns on Example 1 of this invention. It is a flowchart which shows the image process by the pantograph detection apparatus which concerns on Example 2 of this invention. It is a flowchart which shows the image process by the pantograph detection apparatus which concerns on Example 3 of this invention. It is a flowchart which shows the image processing by the pantograph detection apparatus which concerns on Example 4 of this invention. It is a flowchart which shows the image process by the pantograph detection apparatus which concerns on Example 5 of this invention. It is a flowchart which shows the image processing by the pantograph detection apparatus which concerns on Example 6 of this invention. It is explanatory drawing which shows correction | amendment of the center point of a pantograph.

Explanation of symbols

1 Pantograph 2 Camera 3 Pantograph detection device

Claims (6)

In a device in which a camera is installed obliquely with respect to a pantograph that moves up and down, and the position of the pantograph is measured by image processing of an image captured by the camera, the center point of the pantograph is moved along the vertical movement of the pantograph A linear trajectory moving on the image is obtained in advance, and when the input image is image-recognized to obtain the center point of the pantograph, the center point of the pantograph is corrected to be on the linear locus. Pantograph detection device using image processing. In a device in which a camera is installed obliquely with respect to a pantograph that moves up and down, and the position of the pantograph is measured by image processing of an image captured by the camera, the center point of the pantograph is moved along with the movement of the pantograph An apparatus for detecting a pantograph by image processing, wherein a linear locus moving on an image is obtained in advance, and an input image is recognized along the linear locus to obtain a center point of the pantograph. In a device in which a camera is installed obliquely with respect to a pantograph that moves up and down, and the position of the pantograph is measured by image processing of an image captured by the camera, the center point of the pantograph and the other two recognition targets A point is set in advance, each linear trajectory on the image of the two recognition target points accompanying the vertical movement of the pantograph is obtained, an intersection of these linear trajectories is obtained, and the intersection and the center point of the pantograph are connected. When obtaining the center line of the pantograph from the input image, the center point of the pantograph obtained by directly recognizing the input image is corrected so as to be on the third line. An apparatus for detecting a pantograph by image processing, characterized in that a center point is obtained. In a device in which a camera is installed obliquely with respect to a pantograph that moves up and down, and the position of the pantograph is measured by image processing of an image captured by the camera, the center point of the pantograph and the other two recognition target points Is registered in advance as a recognition target image, and the relationship between the recognition target point and the center point of the pantograph is calculated and stored in advance, and the recognition target accompanying the movement of the pantograph Each straight line locus for the point is calculated in advance, and when the position of the pantograph is recognized from the input image, the position of the recognition target point is obtained by performing image recognition on the small region along the straight line locus. , Based on the positional relationship between the recognition target point obtained in advance and the center point of the pantograph, Pantograph detector using image processing and obtaining a point. In a device in which a camera is installed obliquely with respect to a moving pantograph and the position of the pantograph is measured by image processing of an image captured by the camera, the center point of the pantograph and the other two recognition target points are set in advance. And setting and registering a small region including each of the recognition target points as a recognition target image, preliminarily calculating and storing the relationship between the recognition target point and the center point of the pantograph, recognizing the input image, and the center point of the pantograph The recognition target point is obtained by performing image recognition on the small region at a position based on the positional relationship between the recognition target point calculated in advance and the center point of the pantograph, and from the obtained position of the recognition target point An apparatus for detecting a pantograph by image processing, wherein a center point of the pantograph is corrected. In a device in which a camera is installed obliquely with respect to a moving pantograph and the position of the pantograph is measured by image processing of an image captured by the camera, the center point of the pantograph and the other two recognition target points are set in advance. When setting, registering a small region including each of the recognition target points as a recognition target image, calculating and storing the relationship between the recognition target point and the center point of the pantograph in advance, and recognizing the position of the pantograph from the input image in the by performing image recognition on small areas, obtains the recognition target point, the image to constrain the pantograph near the center point based on the positional relationship previously calculated center point of the recognition target point and the pantograph An apparatus for detecting a pantograph by image processing, wherein a center point of the pantograph is obtained by performing recognition.

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