JP2016132313A - Crossing obstacle detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crossing obstacle detection device in which detection performance is improved.SOLUTION: The crossing obstacle detection device includes first detection means 10, second detection means 20, and an arithmetic processing unit 30. The first detection means and the second detection means detect an obstacle in an obstacle detection region by different detection methods or by sensing from different directions. The arithmetic processing unit includes: a first determination part 31 for determining a detection level of each detection section, when the obstacle detection region of the first detection means is equally divided, by using a lower threshold value and an upper threshold value; a second determination part 32 for determining a detection level of each detection section of the second detection means by using the lower threshold value and the upper threshold value; and a last determination part 34 for determining that there is a detected object in the obstacle detection region based on the determination result of each detection section of the first detection part and the determination result of each detection section of the second detection part.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a crossing obstacle detection device.

  When a train approaches a railroad crossing where the railroad track and the road intersect on the same plane, the electric railroad crossing breakers installed at both ends of the railroad crossing close the railroad crossing. When there are obstacles such as automobiles or people in the crossing road, a warning and a warning signal are issued to the train, and the train traffic lights and ground traffic lights are operated to take measures to stop the train. A crossing obstacle detection device that detects the presence or absence of an obstacle in a railroad crossing is used.

  Examples of detection means used to detect an obstacle include an optical sensor (for example, see Patent Document 1), an ultrasonic sensor (for example, see Patent Document 2), a laser radar sensor (for example, see Patent Document 3), a millimeter There are a plurality of types of detection means such as a wave radar sensor (for example, see Patent Document 4), a monocular camera (for example, see Patent Document 5), and a stereo camera (for example, see Patent Document 6). A conventional general railroad crossing obstacle detection device uses one or more of any one of the above-described detection means. The level crossing obstacle detection device that determines that there is an obstacle based on a detection signal that is output when the detection object is detected regardless of the size of the detection object using a detection means such as an optical sensor is a danger. There is a possibility that the train operation may be hindered by malfunction such as issuing an alarm and a warning signal to the train even if there is an inexact object or noise of the detection signal. Therefore, in a more advanced level crossing obstacle detection device, in order to detect a truly dangerous object as an obstacle, an obstacle occurs when the level (detection level) of the detection signal output by the detection means is equal to or higher than a predetermined threshold. When it is determined that there is an object and the detection level is less than the threshold value, the detection signal is excluded as noise, and it is determined that there is no obstacle.

  Further, a technique for combining a plurality of types of sensors has been proposed in order to improve the accuracy of a crossing obstacle detection device. For example, Patent Document 7 discloses a technique for improving the detection accuracy in the vicinity of a shut-off can by combining a radar sensor and an optical sensor.

Japanese Patent Laid-Open No. 5-8731 JP 2014-12457 A JP 2010-42724 A JP 2005-121488 A JP-A-5-54276 JP 2002-145072 A JP 2003-212122 A

  When a threshold is set for the detection level, the conventional level crossing obstacle detection device sets an obstacle detection threshold mainly from the viewpoint of preventing a car from colliding with a train. Only one is set regardless of the change. By the way, there is a possibility that a person who should be detected as an obstacle, i.e., to prevent a train from colliding, may be a drunk person or a sick person who has fallen or crouched in a railroad crossing. . However, such a person may not be detected as an obstacle in the conventional level crossing obstacle detection device. On the other hand, if the threshold value is set low in order to prevent this, there is a problem that erroneous detection occurs excessively.

  When combining a plurality of sensors, a fail-safe configuration is one that issues an alarm and a warning signal to the train when at least one of the plurality of sensors detects an obstacle. However, in this case, there is a problem that erroneous detection is likely to occur compared to the case where each sensor is used alone.

  In the technique of Patent Document 2, a sensor using an energy wave such as an ultrasonic wave and a camera are combined, but the camera is not used to detect an obstacle. If an obstacle cannot be detected by an energy wave sensor, or if the energy wave sensor malfunctions, a human will visually check a composite image that combines the energy wave sensor and the camera output. Judgment must be made on whether or not it is necessary to prevent a collision. Therefore, there are problems such as an increase in human burden and occurrence of human error and reaction time delay.

  The present invention has been made in view of the above points, and an object thereof is to provide a railroad crossing obstacle detection device with improved detection performance.

  In order to achieve the above object, a crossing obstacle detection device according to the present invention includes first detection means, second detection means, and an arithmetic processing unit. The first detection means and the second detection means are obstacle detection. The obstacle in the area is detected by sensing from different detection methods or from different directions, and the arithmetic processing unit is provided for each detection section when the obstacle detection area of the first detection means is divided into predetermined small sections. A first determination unit that determines a detection level using a lower threshold and an upper threshold for the detection level, and a lower threshold and an upper threshold for the detection level for each detection section of the second detection means. When both the determination result for each detection section of the second determination unit for determining the detection level and the determination result for each detection section of the second determination unit are equal to or higher than the upper threshold value, the upper threshold value and the lower threshold value are set. When above, lower threshold When the upper and above the upper threshold value, or when more than the lower threshold or higher and the lower threshold value, and having a with determining the final determination section is detected object to obstacle detection region.

  In another aspect of the crossing obstacle detection device according to the present invention, the first detection means and the second detection means are provided between the timing when the electric railroad crossing breaker of the level crossing rises and the train arrives at the level crossing. The detection operation is started at a predetermined timing, the detection operation is performed at a constant cycle, and the detection operation is stopped after a series of trains arrive at the railroad crossing. When the determination result for each detection section of the first determination unit and the determination result for each detection section of the second determination unit are both equal to or greater than the upper threshold, when equal to or greater than the upper threshold and equal to or greater than the lower threshold, Or when it is equal to or greater than the lower threshold and equal to or greater than the lower threshold, it is determined that there is a detected object in the obstacle detection area.

  In another aspect of the present invention, the first detection means emits a transmission wave to the obstacle detection region at a constant period, receives a reflected wave from the obstacle, and detects the obstacle. The 2 detection means detects an obstacle by performing image processing on image data obtained by imaging the obstacle detection area at a constant cycle by the imaging device.

  In still another aspect of the present invention, the first detection means is any one of a millimeter wave radar sensor, a three-dimensional laser radar sensor, a microwave radar sensor, and an ultrasonic sensor, and the second detection means is a monocular camera, video. An image sensor using either a camera or a stereo camera.

  According to the present invention, an obstacle processed as noise in order to suppress malfunctions is conventionally detected as an obstacle when a certain determination condition is satisfied. Therefore, a crossing obstacle detection device with improved detection performance is provided. Can be provided.

The block diagram which shows the structure of the crossing obstruction detection apparatus which concerns on embodiment of this invention. The top view of a level crossing which illustrates the arrangement | positioning of the detection means at the time of applying this invention to the obstacle detection of a level crossing, and an obstruction detection area | region. The circuit diagram which shows an example of a specific structure in case the 1st detection means of FIG. 1 is a millimeter wave laser sensor. The block diagram which shows a structure in case the 2nd detection means of FIG. 1 is an image sensor. The figure which shows the relationship between each detection result, the primary determination by a determination part, and the determination result by a final determination part in case the 1st detection means of FIG. 1 is a millimeter wave laser sensor and a 2nd detection means is an image sensor. The figure which shows an example of a threshold determination table. FIG. 7 is a diagram illustrating a table when multi-stage weighting is performed on the threshold determination table of FIG. 6. The figure which shows the suitability of the combination of the sensor kind of the 1st detection means and the 2nd detection means of this invention.

  Next, a level crossing obstacle detection apparatus according to an embodiment in which the present invention is applied to level crossing obstacle detection will be described with reference to the drawings.

  As shown in FIG. 1, the level crossing obstacle detection device A includes a first detection means 10, a second detection means 20, and an arithmetic processing device 30 electrically connected to the two detection means 10 and 20. Have. The 1st detection means 10 and the 2nd detection means 20 detect an obstruction by the sensing from a mutually different detection system or a different direction. For example, the first detection unit 10 emits a transmission wave to the obstacle detection area, receives a reflected wave from the obstacle, and detects the obstacle. The second detection unit 20 takes an image with the imaging device. It is an image sensor that processes an image and detects an obstacle.

  As the first detection means 10, any of a millimeter wave radar sensor, a three-dimensional laser radar sensor, a microwave radar sensor, and an ultrasonic sensor can be used. The millimeter wave radar sensor can be used for weather such as rain, fog, and snow. It is the most preferable because it is not easily affected by. Below, the case where the 1st detection means 10 is a millimeter wave radar sensor is demonstrated.

  As shown in FIG. 2, the millimeter wave radar sensor (10) is installed on the side of one end portion in the longitudinal direction of the railroad crossing 3 where the railroad track 1 and the road 2 intersect on the same plane, and the second detection The means 20 is installed on the same side as the first detection means 10 at the other end in the longitudinal direction of the railroad crossing 3. In FIG. 2, 4 is an electric railroad crossing breaker, and 5 is a breaker.

  The millimeter wave radar sensor (10) emits a millimeter wave having a wavelength of 1 to 10 mm and a frequency of 30 to 300 GHz from a transmitting antenna to an obstacle detection area of the railroad crossing 3 and reflects from an object existing in the obstacle detection area. The wave is received by the receiving antenna. The detection signal received and output by the millimeter wave radar sensor (10) includes the reception level, the distance between the emission time and the reception time, distance information to the object in the obstacle detection area, and the object's millimeter wave radar. Relative speed information is included.

  The obstacle detection area of the millimeter wave radar sensor (10) is based on the relationship between the emission angle of the millimeter wave and the width of the railroad crossing 3, and the antenna portion of the millimeter wave radar sensor (10) is arranged as indicated by A1 in FIG. It becomes a sector shape with a radius from the center to the opposite end of the railroad crossing 3. Therefore, when the width of the railroad crossing 3 is narrow, one millimeter wave radar sensor (10) is sufficient. However, when the width of the railroad crossing 3 is wide, in order to make the entire area of the railroad crossing 3 an obstacle detection region. As shown in FIG. 2, it is necessary to provide another millimeter wave radar sensor (10 ′) having A1 ′ as an obstacle detection area on the opposite side to the millimeter wave radar sensor (10) on the diagonal line of the railroad crossing 3. is there.

  In the example shown in FIG. 3, in the millimeter wave radar sensor (10), the frequency-modulated output of the modulation signal generation unit 101 is amplified by the amplifier 102 and then input to the distributor 103, and the output of the distributor 103. Is input to the multiplier 104, amplified by the power amplifier 105, and output from the transmitting antenna 106 to the obstacle detection area A1. When an object is present in the obstacle detection area A1, a reflected wave reflected from the object is received by the receiving antenna 107, and the received signal is amplified by the amplifier 108 and then distributed from the distributor 103 (local signal). Signal) and a beat signal that is superposed in the mixer 109 and converted to a lower frequency. The beat signal is amplified by the low frequency amplifier 110 and input to the processing unit 111.

  At this time, the received wave has a time delay (2 × L / speed of light) of the distance L from the millimeter wave radar sensor (10) to the object, and has a time delay with respect to the transmitted wave, and the frequency is low by that amount ( Or expensive). For this reason, as a result of frequency conversion using the local signal, a beat signal having a frequency corresponding to the distance of the object is input to the processing unit 111, and FFT (Fast Fourier Transform) processing is performed by the processing unit 111. A reflection intensity corresponding to the size of the object is detected. The detection signal S1 output from the processing unit 111 is input to the first determination unit 31 of the arithmetic processing device 30 in FIG.

  The second detection means 20 is an image sensor, and includes an imaging device 21 and an image processing device 22 as shown in FIG. The image sensor (20) detects an object by performing image processing on the image data obtained by capturing the obstacle detection area by the image capturing device 21 frame by frame by the image processing device 22, and according to the size and area of the object as well as the detection position. The detection signal S2 is output. As the imaging device 21, any of a monocular camera, a video camera, and a stereo camera can be used. The viewing angle of the imaging device 21 is set so that the entire area of the railroad crossing 3 is an object to be photographed. However, as illustrated in FIG. 2, when two (10) (10 ′) millimeter wave radar sensors are installed, two image sensors are arranged so that the respective obstacle detection areas A1 and A2 are to be imaged. Individual (20) (20 ') may be installed. The detection signal S2 output from the image processing device 22 is input to the second determination unit 32 of the arithmetic processing device 30 in FIG.

  The millimeter wave radar sensor (10) and the image sensor (20) start the detection operation at a predetermined timing from the rising timing of the shut-off can until the train arrives at the railroad crossing, and perform the detection operation at a constant cycle. It is controlled by a postscript control unit 35 so that the detection operation is stopped after a series of trains arrive at the railroad crossing.

  As shown in FIG. 1, the arithmetic processing device 30 includes a determination threshold value setting unit 33 that sets a determination threshold value of each determination unit, a final determination unit 34, in addition to the first determination unit 31 and the second determination unit 32. And a control unit 35. The determination threshold value setting unit 33 is selectively connected to the first determination unit 31 and the second determination unit 32 via a selection switch (not shown), and operates in the connected state to thereby connect the first connected The lower threshold and the upper threshold (Lt1) (Ht1), (Lt2) (Ht2) can be set in the determination unit 31 or the second determination unit 32, respectively.

  In the first determination unit 31 in which the lower threshold value and the upper threshold value (Lt1) (Ht1) are set, the detection signal S1 input from the processing unit 111 of the millimeter wave radar sensor (10) is equal to or higher than the lower threshold value (Lt1). When the value is less than the upper threshold value (Ht1), the low level determination signal L1 is used as the first determination result. When the detection signal S1 is equal to or higher than the upper threshold value (Ht1), the high level determination signal H1 is used as the first determination result. Output. Similarly, in the second determination unit 32 in which the lower threshold value and the upper threshold value (Lt2) (Ht2) are set, the detection signal S2 input from the image processing unit 22 of the image sensor (20) is equal to or higher than the lower threshold value (Lt2). When it is less than the upper threshold value (Ht2), the low level determination signal L2 is used as the primary determination result. When the detection signal S2 is equal to or higher than the upper threshold value (Ht2), the high level determination signal H2 is used as the primary determination result. Output.

  FIG. 5A schematically illustrates an example in which it is assumed that five types of objects having different sizes exist in the obstacle detection area A1. The white circle is a small object that is judged as noise by the millimeter wave radar sensor (10), the black circle is a small object that is judged as noise by the image sensor (20), and the black star is detected as an obstacle. An object to be taken as an object, such as a person, and a white star is an object that is naturally detected as an obstacle, such as an automobile.

  The detection signal S1 of the millimeter wave radar sensor (10) when an object as shown in FIG. 5 (a) is present in the obstacle detection area A1 is as shown in FIG. 5 (b). This detection signal S1 is a detection signal in one detection cycle of the millimeter wave radar sensor (10). In the figure, a1, a2, a3,..., A8 are obstacle detection sections (hereinafter simply referred to as detection sections) when the longitudinal direction of the obstacle detection area A1 is equally divided. In FIG. 5B, Lt1 and Ht1 are the lower threshold value and the upper threshold value. Accordingly, the first determination unit 31 gives the final determination unit 34 the first determination result S3 as shown in the upper part of FIG. 5D for the object existing in the obstacle detection area A1 of FIG. Output.

  Further, the detection signal S2 of the image sensor (20) when an object as shown in FIG. 5 (a) is present in the obstacle detection area A1 is as shown in FIG. 5 (c). This detection signal S2 is a detection signal in one detection cycle of the image sensor. In the figure, Lt2 and Ht2 are the lower threshold value and the upper threshold value of the image sensor (20). Therefore, the second determination unit 32 gives the final determination unit 34 the first determination result S4 as shown in the lower part of FIG. 5D for the object existing in the obstacle detection area A1 of FIG. Output.

  The detection signal S1 of the millimeter wave radar sensor (10) and the detection signal S2 of the image sensor (20) are input to the first determination unit 31 and the second determination unit 32 for each detection period. 5B and 5C show the detection signal S1 and the detection signal S2 in the same detection cycle.

  The final determination unit 34 detects the detection level determination result S3 of the first detection unit of the first determination unit 31 and the detection level determination result S4 of the second detection unit of the second determination unit 32 in each detection cycle. For a section, when both are above the upper threshold (ie, H1 and H2), when above the upper threshold and above the lower threshold (ie, H1 and L2), above the lower threshold and above the upper threshold (ie, L1 and H2) Or when the value is equal to or greater than the lower threshold value and equal to or greater than the lower threshold value (that is, L1 and L2), it is determined that there is an obstacle in the detection section in the cycle. In the case of the example in FIG. 5, it is determined that there are obstacles in the fourth and seventh detection sections (a4, a7) from the left end of the obstacle detection area A1. Therefore, the white star and the black star in FIG. 5A are detected as obstacles. Then, the final determination unit 34 finally determines that there is an obstacle in the obstacle detection area A1 when it is determined that there is an obstacle in any of the detection sections.

  Detection of detection level for each detection section a1, a2, a3,..., A8 of the obstacle detection area A1 with respect to the detection signal S1 from the millimeter wave radar sensor (10) and the detection signal S2 from the image sensor (20). In order to synchronize the determination and the determination, the control unit 35 provides the millimeter wave radar sensor (10) and the image sensor (20) with a synchronization signal for synchronizing the millimeter wave emission timing and the imaging timing.

  In FIG. 6, the final determination unit 34 finally determines the presence or absence of an obstacle based on the combination of the primary determination result S3 from the first determination unit 31 and the primary determination result S4 from the second determination unit 32. The determination table for this is shown. In the determination table, x indicates determination of noise (no obstacle), and single circle and double circle indicate determination of presence of an obstacle. Since the conventional level crossing obstacle detection device uses only one type of threshold value, it is determined that there is an obstacle only in either the H1 column or the H2 row in the determination table of FIG. Can not do it. Even if the conventional railroad crossing obstacle detection device uses a combination of a millimeter wave radar sensor and an image sensor, it is possible to determine whether there is an obstacle in the H1 column and the H2 row of the determination table of FIG. Obstacles satisfying the conditions of L1 and L2 in the determination table of FIG. 6, for example, the above-described fallen person cannot be detected. However, in this embodiment, it is possible to detect an obstacle that satisfies the conditions of L1 and L2 in the determination table of FIG.

  The lower threshold value and the upper threshold value (Lt1) (Ht1), (Lt2) (Ht2) of the first determination unit 31 and the second determination unit 32 are based on the assumption that there is a correlation between the detection level and the size of the obstacle. It can be set depending on whether an object of a certain size is dealt with as an obstacle. In the determination table of FIG. 6, a double-circle obstacle is generally more dangerous than a single-circle obstacle.

  Therefore, a warning signal (for example, a normal warning signal or a special warning signal) indicating whether the final determination result corresponds to a single circle or a double circle in the determination table of FIG. 6 is output to the final determination unit 34. It is good to add functions. Then, the warning signal is transmitted from the final determination unit 34 to a ground control device (not shown). As a result, when the ground control device receives a normal alert signal, for example, it outputs a control signal for operating a special signal light emitter, and when it receives a special alert signal, it directs it to the level crossing. The emergency stop information can be transmitted to the traveling train through ATC or the like.

  Processing such as emission of special signal light emitters and transmission of emergency stop information after obstacle detection starts after the train passes the railroad crossing start point, but actually starts processing after passing the railroad crossing start point It can be configured so that it can be selected at the discretion of the railway operator whether or not to have a grace period.

  In the above, an example has been described in which the threshold value is set to two levels, a lower threshold value and an upper threshold value, for each sensor. However, the threshold value is set in multiple stages as shown in FIG. By doing so, finer obstacle detection according to the type of obstacle and more appropriate control over the train are possible.

  Appropriateness of the combination of various detection means is shown in the combination table of FIG. In FIG. 8, “millimeter wave” is a millimeter wave radar sensor, “3DLR” is a three-dimensional laser radar sensor, “light” is an optical sensor, “loop” is a loop coil sensor, “stereo” is a stereo camera, and “camera” is Monocular camera, “ultrasonic” is an abbreviation for ultrasonic sensor. The circles in the table indicate that the combination is appropriate, the triangles indicate that the combination is slightly appropriate, and the cross indicates that the combination is inappropriate.

  Depending on the combination of the various detection means, it is possible to provide a level crossing obstacle detection device having a detection capability suitable for the weather and environmental conditions of the level crossing.

  Detection and determination of detection levels for each section a1, a2, a3,... A8 of the obstacle detection area A1 with respect to the detection signal S1 from the first detection means 10 and the detection signal S2 from the first detection means 20 The method of synchronizing is not limited to the above example. The determination results of the first determination unit 31 and the second determination unit 32 are converted into digital values, the respective determination results are stored in a temporary storage unit, and the determination results are read from the temporary storage units in the respective sections a1 and a2. , A3,..., A8 can be synchronized.

A level crossing obstacle detection device A1 obstacle detection area a1, a2,... A8 detection section of obstacle detection area 10 first detection means (millimeter wave radar sensor)
S1 Detection signal of first detection means 20 Second detection means (image sensor)
S2 Detection signal of second detection means 30 Arithmetic processor 31 First determination unit S3 First determination result of first determination unit 32 Second determination unit S4 First determination result of second determination unit 34 Final determination unit S5 Final judgment result

Claims (4)

A first detection unit, a second detection unit, and an arithmetic processing unit;
The first detection means and the second detection means detect obstacles in the obstacle detection area by different detection methods or sensing from different directions,
The arithmetic processing unit includes:
A first determination unit that determines a detection level using a lower threshold and an upper threshold with respect to a detection level for each detection section when the obstacle detection area of the first detection unit is divided into predetermined small sections; ,
A second determination unit that determines a detection level using a lower threshold value and an upper threshold value with respect to the detection level for each detection section of the second detection unit;
When the determination result for each detection interval of the first determination unit and the determination result for the detection interval of the second determination unit are both equal to or higher than the upper threshold, when the determination result is equal to or higher than the upper threshold and equal to or lower than the lower threshold, When the above and the upper threshold or more, or when the lower threshold and more and the lower threshold or more, a final determination unit that determines that there is a detected object in the obstacle detection area,
A crossing obstacle detection device characterized by comprising: In the crossing obstacle detection device according to claim 1,
The first detection means and the second detection means start a detection operation at a predetermined timing from when the train crossing of the electric railroad crossing breaker of the railroad crossing rises until the train arrives at the railroad crossing. The detection operation is performed, and the detection operation is stopped after a series of trains arrive at the railroad crossing.
When the determination result for each detection interval of the first determination unit and the determination result for each detection interval of the second determination unit in the arbitrary period of the detection operation are both equal to or higher than the upper threshold, When it is above the upper threshold and above the lower threshold, when above the lower threshold and above the upper threshold, or when above the lower threshold and above the lower threshold, it is determined that there is an object in the obstacle detection area Is,
A crossing obstacle detection device characterized by that. In the crossing obstacle detection device according to claim 1 or 2,
The first detection means emits a transmission wave to the obstacle detection area at a constant period, receives a reflected wave from the obstacle, and detects the obstacle.
The second detection means detects an obstacle by performing image processing on image data obtained by imaging the obstacle detection area at a constant cycle by an imaging device.
A crossing obstacle detection device characterized by that. In the crossing obstacle detection device according to claim 1, 2, or 3,
The first detection means is any one of a millimeter wave radar sensor, a three-dimensional laser radar sensor, a microwave radar sensor, and an ultrasonic sensor,
The second detection means is an image sensor using any of a monocular camera, a video camera, and a stereo camera.
A crossing obstacle detection device characterized by that.

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