JP6385293B2 - Railroad crossing obstacle detection device - Google Patents

Description

  The present invention relates to a crossing obstacle detection device.

  When a train approaches a railroad crossing where a railroad track and a road intersect on the same plane, the electric railroad crossing breakers installed at both ends of the railroad crossing lower the railroad and close the railroad crossing. When there are obstacles such as automobiles and bicycles in the crossing road that has been used, in order to issue a warning and warning signal to the train, operate the traffic signal of the train and the signal on the ground, and 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 crossing obstacle detection device that determines that there is an obstacle based on a detection signal that is output when the detected object is detected regardless of the size of the detected object using a detection means such as an optical sensor. Even if there is no danger or noise in the detection signal, it is determined that there is an obstacle, and there is a possibility that the operation of the train may be hindered by malfunction such as issuing an alarm and a warning signal to the train. 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, Patent Document 7 discloses a crossing obstacle detection device that eliminates noise of a detection signal due to rain or snow by evaluating the continuity of an obstacle detection signal. Patent Document 8 discloses a crossing obstacle detection device that eliminates noise by performing obstacle determination including the condition that the distance to the obstacle is the same in addition to the detection signal appearing in time series. It is shown.

  Patent Document 9 discloses a crossing obstacle detection device that can prevent erroneous detection due to the influence of the weather by changing the obstacle detection threshold according to the ratio of the region where the detection level reaches a predetermined value. ing. On the other hand, Patent Document 10 discloses a crossing obstacle detection device that can prevent erroneous detection by performing automatic gain control on a detection signal instead of changing a threshold value. Patent Document 11 discloses a crossing obstacle detection device that can prevent erroneous detection by performing obstacle determination after removing noise components from a detection signal based on a spectral subtraction method. . Patent Document 12 discloses an obstacle detection method in which a detection signal is compared with a preset reference pattern and an obstacle is determined by comparison with a reference pattern that is most suitable.

  Patent Document 13 discloses a crossing obstacle detection device having an object tracking function. Patent Document 14 discloses a method of dividing a detection area into a plurality of areas and detecting that an object has accumulated in one of the divided areas.

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 Japanese Patent No. 4117581 Japanese Patent No. 5134453 JP 2012-101620 A Japanese Patent No. 2802056 JP 2013-1263 A JP 2012-101621 A JP 2012-101622 A JP-A-2005-214718

  When a threshold is set for the detection level, the conventional level crossing obstacle detection device mainly uses a threshold for obstacle detection from the viewpoint of protecting an object having a certain height, area, size, or the like such as an automobile or a bicycle from a train collision. However, only one threshold is basically set regardless of the change in the condition of the obstacle. By the way, as an object that should be detected as an obstacle, that is, to be protected from a train collision, not only an object whose height, area, or size does not change from start to finish, but also a height, area, or size, etc. Some things can change. For example, if a drunk person, sick person, etc. enters the railroad crossing and then falls, leans, or conversely, if a fallen thing stands up and moves from the railroad crossing to the road, the height, area, or size It changes.

  In the conventional level crossing obstacle detection device, there is a possibility that an object whose height, area, size, or the like that should be detected as an obstacle is not detected as an obstacle. In order to prevent this, if the threshold value is set low and an object with a smaller height, area, size, etc. is determined to have an obstacle, over-detection will occur, resulting in a malfunction. .

  The techniques for suppressing erroneous detection due to noise disclosed in Patent Documents 7 to 12 are mainly for dealing with relatively slow or global changes such as weather. For this reason, it is not necessarily effective for a relatively steep and local change such as a human fall on a railroad crossing.

  Further, the techniques of Patent Document 13 and Patent Document 14 track a detected object, and do not mention the threshold of the detection level. Therefore, at the time of starting tracking, the above-described problem of false detection exists. In addition, since tracking the object is fundamental, depending on the ability of the sensor, separation or fusion of detected objects (for example, a person who was riding a bicycle was walking away, walking 2 away) There is a possibility that the bankruptcy will occur in the situation of people walking together.

  The present invention has been made in view of the above points, and an object whose state such as height, area, or size that should be originally detected as an obstacle can be reliably detected as an obstacle, and malfunction can be prevented. An object of the present invention is to provide a crossing obstacle detection device that can be suppressed.

  In order to achieve the above object, a crossing obstacle detection device according to the present invention includes a detection means and an arithmetic processing unit, and the detection means performs detection operation on an obstacle detection area at a constant cycle, and detects a detection signal. The arithmetic processing unit outputs a lower threshold value and an upper threshold value with respect to the detection level corresponding to each of the detection sections obtained by dividing the obstacle detection area into predetermined small sections from the detection signal output by the detection means. The detection means for detecting the detection level of the detection signal input every period from the detection means, the storage means for storing the detection results of the detection means in time series, and the current cycle If the detection result in any section of the obstacle detection area is equal to or higher than the upper threshold, it is determined that there is an obstacle, and the detection result in any section of the obstacle detection area in the current cycle is equal to or higher than the lower threshold When it is below the threshold, If the detection result of the same section of the obstacle detection area in the immediately preceding cycle is greater than or equal to the upper threshold value, or the detection result of the same section of the obstacle detection area is retroactively time-sequentially and passes below the lower threshold value And determining means for continuing the determination that there is an obstacle when the value can reach the upper threshold value or more without doing so.

  In another aspect of the level crossing obstacle detection device according to the present invention, the determination means determines that the obstacle is detected when the detection result of an arbitrary section of the obstacle detection area in the current cycle is equal to or higher than the lower threshold and lower than the upper threshold. When the detection result of the section in the vicinity of the section of the object detection area is equal to or higher than the upper threshold in the immediately preceding cycle, or the detection result of the same section of the obstacle detection area is retrospectively traced in time series, If it is possible to reach the upper threshold or higher without passing through the lower threshold, the determination that there is an obstacle is continued.

  In still another aspect of the level crossing obstacle detection device according to the present invention, the detection means starts the detection operation at the timing when the electric level crossing breaker lifts off, performs the detection operation at a constant cycle, and the train The detection operation is stopped before the railroad crossing is reached, and the determination means determines that there is an obstacle when the detection result in an arbitrary section of the obstacle detection area in the last cycle of the detection operation is equal to or higher than the upper threshold. When the detection result of an arbitrary section of the obstacle detection area in the last cycle of the detection operation is equal to or higher than the lower threshold and lower than the upper threshold, the detection result of the same section of the obstacle detection area of the immediately preceding cycle is If it is above the upper threshold, or if the detection result of the same section of the obstacle detection area is retroactively traced in chronological order and can reach the upper threshold or higher without going below the lower threshold, the obstacle That there is It is intended to continue.

  According to the present invention, not only an obstacle having a certain height, area, size, etc., but also an object whose height, area, size, etc., which should be detected as an obstacle originally have changed, can be reliably regarded as an obstacle. Can be detected. Moreover, since the discrimination performance between an obstacle and noise is enhanced, malfunction due to noise can be suppressed.

The block diagram which shows the structure of the crossing obstruction detection apparatus which concerns on embodiment of this invention. The figure explaining the obstacle detection logic when the magnitude | size of the obstacle by this invention changes. The flowchart explaining the effect | action of the arithmetic processing apparatus of FIG. The flowchart explaining the detail of the obstruction presence determination of FIG. 3A. The figure explaining the obstacle detection at the time of moving and falling after approaching a railroad crossing. The block diagram which shows the structure of the crossing obstruction detection apparatus which concerns on other embodiment of this invention. FIG. 6 is a plan view of a crossing illustrating the arrangement of the detection means and the obstacle detection area of the crossing obstacle detection device of FIG. 5. The circuit diagram which shows an example of a specific structure in case the 1st detection means of FIG. 6 is a millimeter wave laser sensor. The block diagram which shows a structure in case the 2nd detection means of FIG. 6 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 when the 1st detection means of FIG. 6 is a millimeter wave laser sensor and a 2nd detection means is an image sensor. The figure which shows an example of the determination table. The figure which shows the determination table at the time of providing the threshold value of a multistep in the determination table of FIG.

  Next, embodiments of the present invention will be described with reference to the drawings.

<First Embodiment>
[Constitution]
As shown in FIG. 1, a crossing obstacle detection device 1 according to an embodiment of the present invention includes a detection means 10 and an arithmetic processing device 20.

  As illustrated in FIG. 2A, the detection means 10 is a sensor that uses all or part of the railroad crossing 5 as an obstacle detection region A, and is different in the height, area, size, and the like of the detected object. A different detection signal s1 is output in accordance with. The detection signal s1 can be projected to a real number, and the projection result, that is, the detection level takes the form of a voltage level, for example.

  As such a detecting means 10, for example, a laser radar sensor, a millimeter wave radar sensor, an image sensor, or the like can be used.

  When the detection means 10 is a laser radar sensor, a millimeter wave radar sensor or the like, a transmitter (not shown) is controlled, and a transmission wave is emitted intermittently toward an obstacle detection region from a transmission antenna (not shown). When the reflected wave is received by the receiver via a receiving antenna (not shown), the detection means 10 outputs a different detection signal s1 depending on the difference in height, area, size, etc. of the detected object. To do. The detection signal s1 includes distance information to the object in the obstacle detection area and reflection intensity information obtained from the difference between the transmission wave and the reflected wave. Although depending on the material and shape of the detected object, in many cases, the reflection intensity tends to increase as the detected object increases.

  Image sensors applicable to the detection means 10 are monocular cameras, stereo cameras, and the like, and shape recognition processing and pattern matching processing are performed for each frame of image data obtained by continuously or intermittently capturing an obstacle detection region. The detection signal s1 that differs depending on the height, area, size, etc. of the object to be detected is output.

  The arithmetic processing unit 20 includes a detection unit 21, a storage unit 22, a determination unit 23, and an output unit 24. The detection means 21 receives the detection signal s1 output from the detection means 10. In the detection means 21, two types of threshold values, a lower threshold value L and an upper threshold value H, are set as threshold values for detecting the detection level of the input detection signal s1.

  Thereby, when the detection signal s1 from the detection means 10 is input to the detection means 21, the detection level of the detection signal s1 is formed by dividing the obstacle detection area A into predetermined small sections (details). Is compared with the lower threshold value L and the upper threshold value H, and whether the detection level is less than the lower threshold value L, greater than or equal to the lower threshold value L and less than the upper threshold value H, or greater than or equal to the upper threshold value H is detected. Is done. Then, the detection result s2 is given from the detection means 21 to the storage means 22 and stored. The storage unit 22 stores at least the detection result s2 (s2n) of the current detection cycle and the detection result s2 (s2b) of the previous detection cycle.

  The detection means 10 starts the detection operation when the electric railroad crossing breaker 7 rises, that is, when the train passes the end point of the railroad crossing, and detects when the next train arrives at the railroad crossing in time series. It is controlled to end the operation. Since the detection signal s1 is input from the detection unit 10 to the detection unit 21 at predetermined time intervals, the detection result s2 output from the detection unit 21 is stored in the storage unit 22 in time series. It is configured to be. Note that the detection means 10 always performs the detection operation, and the detection means 21 permits the input of the detection signal s1 only from the time when the train passes the final crossing point to the time when the next train arrives at the crossing. However, the detection signal s1 may be discarded at other times.

  Of the detection results stored in the storage unit 22, the determination unit 23 reads the detection result s2 (s2n) of the current detection cycle and the detection result s2 (s2b) of the previous detection cycle, and the two detection results s2 The presence or absence of an obstacle is determined based on whether or not the time series change of (s2n, s2b) satisfies a predetermined condition. That is, for each detection interval, the detection result s2 (s2n) of the current detection cycle is greater than or equal to the lower threshold L and less than the upper threshold H, and the detection result s2 (s2b) of the immediately previous detection cycle is greater than or equal to the upper threshold H. If there is, the detection result s2 (s2n) of the current detection period in the detection section is updated to the upper threshold value H or higher. As a result of the update, if it is equal to or higher than the upper threshold value H in any detection section, it is determined that an obstacle exists in the obstacle detection area A in the current detection cycle. Since the updated detection result s2 (s2n) of the current detection cycle is used for determination in the next detection cycle, the determination unit 23 outputs the updated detection result s2 (s2n) of the current detection cycle to the storage unit 22. Then, the storage means 22 overwrites the detection result s2 (s2n) of the current detection cycle with the update result. Thereby, when it is determined that an obstacle exists in the obstacle detection area A in the immediately preceding detection cycle, the detection result s2 (s2n) of the current detection cycle is decreased in the detection zone in the vicinity where the obstacle is detected. When the threshold value is changed to the threshold value L or higher and lower than the upper threshold value H, the detection result of the lower threshold value L or higher and lower than the upper threshold value H is determined to be due to the same object as that determined to exist in the immediately preceding detection cycle. Then, the determination that there is an obstacle continues even in the current detection cycle.

  The train passes the end point of the railroad crossing to check the time-series change of the detection result s2 (s2b) of the immediately preceding detection cycle and the detection result s2 (s2n) of the current detection cycle and the determination of the presence or absence of an obstacle as described above. It starts from the point of time, and is performed at a constant period until the next train arrives at the railroad crossing in time series. Then, the determination result s3 of the determination unit 23 is output to the output unit 24 from the time when the train approaches the level crossing, that is, from the time when a predetermined time has passed since the train crossing starting point passed to the time when the train arrives at the level crossing. To do.

  The output unit 24 outputs the determination result s3 to the ground control device 2. When the determination result s3 is that there is an obstacle, the ground control device 2 sends a control signal s4 for driving the special signal light emitter 3 to call attention to the train traveling toward the railroad crossing, or the train The control signal s5 for applying the brake to the on-vehicle device 4 is sent out. The control signal s5 may be sent directly from the output means 24 to the on-board device 4 via the rail or wirelessly without using the ground control device 2.

[Action]
Next, the effect | action of the arithmetic processing unit 20 is demonstrated based on FIG. 3A and 3B. The arithmetic processing unit 20 starts the operation from the time when the train passes the final crossing point. Whether the detection signal s1 is input from the detection means 10 to the detection means 21 is constantly monitored (step S1). When the detection signal s1 is input, the detection means 21 detects the detection level of the detection signal s1. Each interval is compared with the lower threshold value L and the upper threshold value H (step S2). That is, it is detected whether the detection level is lower than the lower threshold L, lower threshold L or higher and lower upper threshold H, or upper threshold H or higher. The detection result s2 for each detection section is stored in the storage means 22 (step S3). The detection results s2 stored in the storage unit 22 are sequentially read out and given to the determination unit 23, and the determination unit 23 performs an obstacle presence / absence determination process (step S4).

  As shown in detail in FIG. 3B, the obstacle presence / absence determination process first selects one detection section in which the processing of steps S42 to S44 described later is not performed in the current detection cycle (step S42). S41).

  Next, for the selected detection section, it is checked whether or not the detection result s2 (s2n) of the current detection cycle read from the storage unit 22 is equal to or higher than the lower threshold L and lower than the upper threshold H (step S42). . If it is determined that the threshold value is greater than or equal to the lower threshold value L and less than the upper threshold value H, is the detection result s2 (s2b) of the immediately preceding detection cycle read from the storage means 22 for the selected detection interval equal to or greater than the upper threshold value H Whether or not is checked (step S43). If it is determined that the value is equal to or higher than the upper threshold value H, the detection result s2 is updated when the detection result s2 (s2n) of the current detection period in the selected section is equal to or higher than the upper threshold value H (step S44). The updated detection result s2 is output to the storage means 22 at the stage of step S44 or before the end of the current processing cycle, and the detection result s2 updated by overwriting is stored.

  If it is determined in step S42 that it is less than the lower threshold value L or greater than or equal to the upper threshold value H, or if it is determined that it is less than the upper threshold value H in step S43, the detection result s2 is not updated. .

  For all detection sections, the process returns to step S41 until the processing of step S42 to step S44 is completed (step S45).

  After the processing of step S42 to step S44 is completed for all the detection sections, it is checked whether or not the detection result s2 (s2n) of the current detection cycle is equal to or higher than the upper threshold value H in any detection section (step S46). If it is less than the upper threshold value H in any detection section, it is determined that there is no obstacle (step S47). If it is equal to or higher than the upper threshold value H in any detection section, it is determined that there is an obstacle (step S48).

  After the obstacle presence / absence determination process ends, the process proceeds to step S5 in FIG. 3A.

  After the above-described obstacle presence / absence determination process in step S4, it is checked in step S5 whether or not the train has approached the railroad crossing. If not, the process returns to step S1. After approaching, the determination unit 23 outputs the determination result s3 to the output unit 24 (step S6). Then, in step S7, it is checked whether or not the train has reached the railroad crossing.

  For the sake of simplicity, the operation in the case where only one train passes through the railroad crossing during one descent / rise operation of the circuit breaker 7 has been described. In the general case, that is, on the premise that a plurality of trains pass during one descent / rise operation of the breaker 7, the time when each train has passed the level crossing regardless of the descent / rise of the breaker 7. The arithmetic processing unit 20 starts (restarts) the operation. However, in step S6 of FIG. 3A, while any train passes through the railroad crossing, the output of the determination result s3 is interrupted or output as no obstacle so that the train is not detected as an obstacle. If there is a separate means for distinguishing whether the detected object is an obstacle or a train passing through a level crossing, the detected object is an obstacle using that means. The determination result s3 (with an obstacle) may be output only for.

  Next, the operation of the level crossing obstacle detection apparatus 1 when a person who enters the level crossing falls down will be described with reference to FIG. FIG. 2A shows a detection means 10 installed at one end in the longitudinal direction of the railroad crossing 5, for example, a transmission wave emitted from a transmission antenna of a millimeter wave radar sensor to the obstacle detection area A. 1 schematically shows a situation in which reflected waves from the objects 6a, 6b, and 6c existing in FIG. 1 are received by the receiving antenna of the millimeter wave radar sensor. Then, it is assumed that the object 6a represented by a white star is a person standing at time t1, and the object 6b represented by a black star is a person who has fallen at time t2. Here, the object 6a and the object 6b are the same person. An object 6c represented by a small black circle is a small object that does not need to be detected as an obstacle. In FIG. 2 (a), reference numeral 7 denotes an electric railroad crossing breaker, and 8 denotes the cutting.

The detecting means 10 emits a transmission wave and receives a reflected wave at a predetermined detection cycle t1, t2, t3,..., Tn, and according to the intensity of the reflected wave from each object 6a, 6b, 6c. The detection signal s1 is output. The detection means 21 of the arithmetic processing unit 20 inputs the detection signal s1 at the same detection cycle t1, t2, t3,..., Tn, and the detection level of the detection signal s1 as shown in FIG. Are detected for each of the sections (detection sections) a1, a2, a3,..., Equally divided in the longitudinal direction of the obstacle detection area A, and the detected detection levels are set to the lower threshold value L and the upper threshold value H. Compare with The upper part of (b) shows the detection signal s1 of the detection means 10 in the detection period t1, and the lower part of (b) shows the detection signal s2 of the detection means 10 in the detection period t2.

  In the detection cycle t1, the detection level corresponding to the detection section a4 of the detection signal s1 corresponds to the object 6a represented by the white star in FIG. In this case, since the detection means 21 detects the detection level of the detection interval a4 as being the upper threshold value H or more, as shown in FIG. 2C, the storage means 22 corresponds to the detection interval a4 of the detection cycle t1. Then, “H” (meaning higher than the upper threshold value H) is stored. The detection level corresponding to the detection section an-1 corresponds to the object 6c represented by the black circle in FIG. 2A, and is not less than the lower threshold L and less than the upper threshold H. In this case, since the detection means 21 detects the detection level of the detection interval an-1 as being equal to or higher than the lower threshold L and lower than the upper threshold H, the storage means 22 corresponds to the detection interval an-1 of the detection cycle t1. Then, “L” (meaning lower than threshold L and lower than upper threshold H) is stored. The other blank portion in FIG. 2C means that it is less than the lower threshold, and the information is also stored in the storage means 22. However, since states other than “H”, “L”, and blank cannot be taken, it is sufficient if, for example, “H” and “L” detection sections are stored.

On the other hand, in the detection cycle t2, the detection level in the detection section a4 of the detection signal s2 corresponds to the object 6b represented by the black star in FIG. 2A, and is equal to or higher than the lower threshold L and lower than the upper threshold H. is there. In this case, since the detection unit 21 detects the detection level of the detection section a4 as “L”, the storage unit 22 stores “L” corresponding to the detection section a4 of the detection cycle t2. The detection level of the detection section an-1 in the detection cycle t2 corresponds to the fact that the object 6c represented by the black circle in FIG. 2A exists as it is. Since the detection level of the section an-1 is detected as “L”, “L” is stored in the storage unit 22 corresponding to an−1 of t2 .

  Therefore, the detection levels of the detection sections a1, a2, a3,..., An stored in the storage means 22 in the immediately preceding detection cycle t1 and the current detection cycle t2 are as shown in FIG. In the detection interval a4, “H” changes to “L”, and in an−1, “L” changes to “L” in time series.

  When the detection level of the detection interval a4 in the current detection cycle t2 is equal to or higher than the lower threshold L and lower than the upper threshold H, the determination unit 23 examines the detection level of the detection interval a4 in the immediately preceding detection cycle t1. As described above, the detection level in the detection interval a4 in the current detection cycle t2 is updated to the upper threshold H or higher, and the determination that there is an obstacle in the detection interval a4 in the immediately preceding detection cycle t1 is continued. Since the detection level in the detection interval an-1 in the current detection cycle t2 is also equal to or higher than the lower threshold L and lower than the upper threshold H, when the detection level in the detection interval an-1 in the immediately preceding detection cycle t1 is examined, the lower threshold Since it is not less than L and less than the upper threshold value H, it is determined that there is no obstacle in the detection section an-1 alone. After all, in the presence situation of the object shown in FIG. 2A, the crossing obstacle detection apparatus 1 has the same object 6b in the current detection cycle t2 as the object 6a determined as an obstacle in the immediately preceding detection cycle t1. Therefore, the object 6b can also be detected as an obstacle.

  On the other hand, in FIG. 2A, assuming a new situation where only the object 6c exists, the crossing obstacle detection device 1 does not determine the object 6c that does not need to be detected as an obstacle as an obstacle. That is, erroneous detection is prevented.

  However, when the object 6c is regularly detected as “L”, if an obstacle that is detected as “H” once enters an-1, even if only the object 6c exists, The obstacle detection device 1 determines that there is an obstacle.

  By the way, in step S44 of FIG. 3B, the reason for overwriting the detection result s2 (s2n) of the current detection cycle is that a time-series check can be realized by referring only to the detection result s2 (s2b) of the immediately preceding detection cycle, This is because the storage area and processing time during mounting can be reduced. If there is a margin in the restrictions on the storage area and processing time at the time of mounting, an equivalent function can be realized without overwriting the detection result s2 by recursively referring to the detection result s2 of the past detection cycle. That is, as long as the detection result s2 of the detection section is equal to or higher than the lower threshold L and lower than the upper threshold H, the detection result s2 of the detection section one cycle before is referred to and the upper side without passing through the lower threshold L If the threshold value H or higher can be reached, it may be processed that there is an obstacle in the detection section.

  If the above method recursively refers to the detection result s2 of the past detection cycle, it is possible to set a restriction as to which detection cycle can be retroactive. By providing a restriction on the retroactive detection cycle, even if the object 6c is constantly detected as “L” in FIG. It is possible to avoid determining that there is an obstacle as necessary.

  The obstacle detection area A by the detection means 10 in FIG. 2A covers only half the area of the railroad crossing 5. Therefore, in order to cover the other half, another detection means is installed at a position near the right corner of the railroad crossing 5 in FIG. This detection means is also connected to the arithmetic processing unit 20. Another detection means emits a transmission wave when the detection means 10 is not emitting a transmission wave, for example, in order to prevent interference with the detection means 10. Alternatively, a transmission wave shifted from the transmission frequency of the detection means 10 may be emitted to prevent interference.

  In the above example, the method of detecting an obstacle when a person falls in one detection section has been described. However, the direction in which a person falls may be perpendicular or oblique to the boundary direction of the detection section. obtain. In this case, the detection section where the person exists before and after the fall may change in time series.

  FIG. 4 shows that the detection level in the detection section a4 is equal to or higher than the upper threshold value H in the detection cycle t1, but the detection level in the detection section a4 is less than the lower threshold value L in the detection cycle t2, and instead the detection section An example of a situation in which the detection level is detected as a value equal to or higher than the lower threshold value L and lower than the upper threshold value H in a5 is shown. Here, the detection level of the detection section a5 in the detection cycle t1 is less than the lower threshold L. From this fact, it can be estimated that the object in the section a4 in the detection cycle t1 has moved to the detection section a5 by the detection cycle t2 and has become smaller in height or size, that is, collapsed.

<Second Embodiment>
In another embodiment of the present invention, in order to enable detection even in such a case, the determination unit 23 is caused to execute the following determination algorithm. That is, “H” is detected in a detection interval (a4) in the immediately preceding detection cycle (t1), and “H” is detected in the detection interval (a5) in the vicinity of the detection interval (a4) in the next detection cycle (t2). , L is determined, the object to be determined is regarded as having moved to the adjacent detection section (a5) in the detection period (t1) immediately preceding the detection period (t4). Therefore, it is determined that there is an obstacle.

  The obstacle presence / absence determination of the second embodiment will be described based on the flowchart of FIG. 3B. In FIG. 3B, not only the selected detection section but also the detection result s2 (s2b) of the detection period immediately before the detection section in the vicinity of the selected detection section is examined in step S43, and is any one higher than the upper threshold value H? Change to determine. Thereby, the second embodiment is realized, and it is possible to cope with the case where the existing detection section and the detection level change in time series.

  The range of the nearby detection section is determined depending on the distance of one detection section or the like, but can be determined based on the average movement distance when the obstacle falls during one cycle.

  The second embodiment is characterized by tracking an object, but is essentially different from Patent Document 13 and Patent Document 14 in that the tracking result is fed back to a detection level threshold. In addition, since the tracking result is used to discriminate signals and noises due to obstacles that should be detected, even if tracking fails due to separation / fusion of detected objects, it can function as a crossing obstacle detection device. There is no bankruptcy.

<Third Embodiment>
In the above embodiment, the relationship between the lower threshold value L and the upper threshold value H of the detection level of the detection signal s1 output from the detection means 10 is checked in time series, and the obstacle is when the relationship satisfies a certain condition. It is determined that there is. A crossing obstacle detection device that further improves the obstacle detection performance by adding another configuration to the above crossing obstacle detection device will be described with reference to FIG.

  As shown in FIG. 5, the crossing obstacle detection device 1 ′ includes a first detection means 100, a second detection means 200, and an arithmetic processing device 300 electrically connected to the two detection means 100 and 200. And have. The 1st detection means 100 and the 2nd detection means 200 detect an obstruction by the sensing from a mutually different detection system or a different direction. For example, the first detection unit 100 emits a transmission wave to the obstacle detection region, receives a reflected wave from the obstacle, and detects the obstacle, and the second detection unit 200 is an image sensor. .

  As the first detection means 100, any of a microwave radar sensor, a laser radar sensor, a millimeter wave radar sensor, and an ultrasonic sensor can be used, but the millimeter wave radar sensor is influenced by weather such as rain, fog, and snow. It is most preferable because it is difficult to receive. Below, the case where the 1st detection means 100 is a millimeter wave radar sensor is demonstrated.

  As shown in an example in FIG. 6, the millimeter wave radar sensor (100) is installed on the side of one end in the longitudinal direction of the railroad crossing 5C where the railroad track 9 and the road 5R intersect on the same plane, and the second detection The means 200 is installed on the same side as the first detecting means 100 at the other end in the longitudinal direction of the railroad crossing 5C. In FIG. 6, 7 is an electric railroad crossing breaker, and 8 is a wire breaker.

  The millimeter wave radar sensor (100) emits a millimeter wave having a wavelength of 1 to 10 mm and a frequency of 30 to 300 GHz from a transmission antenna, receives the reflected wave by a reception antenna, and takes a crossing from a difference between the transmission wave and the reception wave. It has a function of measuring the distance to the obstacle and the reflection intensity in the obstacle detection area of the road 5C.

  The obstacle detection area of the millimeter wave radar sensor (100) is based on the relationship between the emission angle of the millimeter wave and the width of the railroad crossing 5C, as shown by A1 in FIG. A sector is formed with a radius from the center to the end on the opposite side of the level crossing 5C. Therefore, in order to make the whole area of the railroad crossing 5C an obstacle detection region, another millimeter wave radar having A2 as an obstacle detection region on the opposite side of the millimeter wave radar sensor (100) on the diagonal line of the railroad crossing 5C. It is necessary to provide a sensor (100 ′).

  In the millimeter wave radar sensor (100), as shown in FIG. 7, 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 output. After a part is input to the multiplier 104, it is amplified by the power amplifier 105 and emitted 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 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). ) And a beat signal that is polymerized 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 with respect to the transmission wave (2 × L / velocity of light) at a distance L from the millimeter wave radar sensor (100) to the object, and the frequency is low by that time ( Or high). For this reason, as a result of frequency conversion with the local signal, beat signals having different frequencies according to the distance of the object are input to the processing unit 111, and the processing unit 111 performs FFT (Fast Fourier Transform) processing up to the object. The reflection intensity corresponding to the distance and the size of the object is detected. The detection signal s11 output from the processing unit 111 is input to the first determination unit 306 of the arithmetic processing device 300 in FIG.

  The second detection means 200 is an image sensor, and includes an imaging device 201 and an image processing device 202 as shown in FIG. The image sensor (200) detects an object by performing image processing on the image data obtained by capturing the obstacle detection area by the image capturing apparatus 201 using the image processing apparatus 202, and outputs a detection signal s12 corresponding to the size of the object. It is. As the imaging device 201, any of a monocular camera, a video camera, and a stereo camera can be used. The viewing angle of the imaging device 201 is set so that the entire area of the railroad crossing 5C is a subject to be photographed. However, as illustrated in FIG. 6, when two (100) (100 ′) millimeter wave radar sensors are installed, two image sensors are provided so that the respective obstacle detection areas A1 and A2 are to be imaged. Individual (200) (200 ') may be installed. The detection signal s12 output from the image processing apparatus 202 is input to the second determination unit 307 of the arithmetic processing apparatus 300 in FIG.

  As shown in FIG. 5, the arithmetic processing device 300 includes a control unit 301, a detection unit 302, a storage unit 303, an auxiliary determination unit 304, an output unit 305, the first determination unit 306, and the first 2 determination unit 307 and final determination unit 308.

  The detection unit 302, the storage unit 303, the auxiliary determination unit 304, and the output unit 305 are equivalent to the detection unit 21, the storage unit 22, the determination unit 23, and the output unit 24 of FIG. Then, the same operation for obstacle detection as described in the previous embodiment is performed on the detection signal s11 input from the first detection unit 100, and the determination result is output to the output unit 305.

  As will be described later, the control unit 301 provides a control signal for making the transmission cycle of the millimeter wave radar sensor (100) and the imaging cycle of the image sensor (200) coincide, and the detection unit 302 and the first determination unit. The lower threshold value and the upper threshold value (L) (H), (Lt1) (Ht1), (Lt2) (Ht2) are set in 306 and the second determination unit 307, respectively.

Then, the first determination unit 306 in which the lower threshold value and the upper threshold value (Lt1) (Ht1) are set, the detection signal s11 input from the processing unit 111 of the millimeter wave radar sensor (100) sets the lower threshold value (Lt1). When it exceeds, the low level determination signal L1 is output as the primary determination result s21, and when the detection signal s11 exceeds the upper threshold (Ht1), the high level determination signal H1 is output as the primary determination result s21. Similarly, in the second determination unit 307 in which the lower threshold value and the upper threshold value (Lt2) (Ht2) are set, the detection signal s12 input from the image processing unit 202 of the image sensor (200) sets the lower threshold value (Lt2). When it exceeds, the low level determination signal L2 is output as the primary determination result s22, and when the detection signal s12 exceeds the upper threshold (Ht2), the high level determination signal H2 is output as the primary determination result s22.

  FIG. 9A schematically shows 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 detected as noise by the millimeter wave radar sensor (100), and the black circle is a small object that is detected as noise by the image sensor (200). These are detected as obstacles. It should not be an object. A black star is an object to be detected as an obstacle, for example, a fallen person, and a white star is an object that is naturally detected as an obstacle, for example, an automobile.

  The detection signal s11 of the millimeter wave radar sensor (100) when the object as shown in FIG. 9A exists in the obstacle detection area A1 is as shown in FIG. 9B. Therefore, the first determination unit 306 sends the first determination result s21 as shown in the upper part of FIG. 9D to the final determination unit 308 for the object existing in the obstacle detection area A1 of FIG. Output.

Further, the detection signal s12 of the image sensor (200) when the object as shown in FIG. 9A exists in the obstacle detection area A1 is as shown in FIG. 9C. Therefore, for the object existing in the obstacle detection area A1 in FIG. 9A, the second determination unit 307 gives the first determination result s22 as shown in the lower part of FIG. Output.

The final determination unit 308 uses the first determination result s21 from the first determination unit 306 and the first determination result s22 from the second determination unit 307 as the millimeter wave radar sensor (100) and the image sensor in the obstacle detection area A1. (200) is counted for each obstacle detection section (a1, a2, a3,..., An-1, an). When both of the obstacle detection sections are equal to or higher than the upper threshold (that is, H1 and H2), when they are equal to or higher than the upper threshold and equal to or higher than the lower threshold (that is, H1 and L2), When it is above (that is, L1 and H2), or when it is above the lower threshold and above the lower threshold (that is, L1 and L2), it is finally determined that there is an obstacle in the detection section in the cycle. To do. In the case of the example of FIG. 9A, as shown in FIG. 9E, if there are obstacles in the fourth and seventh sections (a4, a7) from the left end of the obstacle detection area A1. judge. Therefore, the white star and the black star in FIG. 9A are detected as obstacles.

  The final determination unit 308 uses the first determination result s21 from the first determination unit 306 and the first determination result s22 from the second determination unit 307 as the millimeter wave radar sensor (100) and the image sensor in the obstacle detection area A1. (200), the final determination unit 308 of the first determination result s21 from the first determination unit 306 and the first determination result s22 from the second determination unit 307. In order to synchronize the input timing to the control unit 301, the control unit 301 provides the millimeter wave radar sensor (100) and the image sensor (200) with a synchronization signal that synchronizes millimeter wave emission and imaging.

  In FIG. 10, the final determination unit 308 finally determines the presence or absence of an obstacle based on the combination of the primary determination result s21 from the first determination unit 306 and the primary determination result s22 from the second determination unit 307. The judgment table explaining logic 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 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. I can't. Even if a conventional 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 H2 column of the determination table of FIG. An obstacle that satisfies the conditions of L1 and L2 in the determination table of FIG. 10, 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 306 and the second determination unit 307 are set depending on how large an object is handled as an obstacle. be able to. In the determination table of FIG. 10, double-circle obstacles are generally more dangerous than single-circle obstacles.

  Therefore, when the present embodiment is applied to a crossing obstacle detection device, a warning signal indicating whether the final determination result corresponds to the single circle or the double circle of the determination table of FIG. A function for outputting (for example, a normal alert signal and a special alert signal) may be added. Then, the warning signal is transmitted from the output unit 305 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. It is possible to output a control signal for applying a brake to a traveling train.

  In the above, an example has been described in which the threshold value is set to two levels of the lower threshold value and the upper threshold value for each sensor (100, 200), but the threshold value is set in multiple stages as shown in FIG. Furthermore, by performing weighting or the like, finer obstacle detection according to the type of obstacle and more appropriate control over the train are possible.

  Moreover, it is possible to provide an obstacle detection device having a detection capability adapted to the weather and environmental conditions of the railroad crossing depending on the combination of the various detection means.

  In another configuration of the third embodiment, the detection unit 302, the storage unit 303, and the auxiliary determination unit 304 of FIG. 5 are removed. In exchange, the equivalent time-series processing is performed by the first determination unit 306 and the second determination unit 304. This is performed by the determination unit 307. If the first determination unit 306 and the second determination unit 307 determine that there is an obstacle, the upper threshold value even if the detection level of the detection section is equal to or higher than the lower threshold value and less than the upper threshold value (L1, L2). The data is rewritten as (H1, H2) and output to the final determination unit 308.

  In still another configuration of the third embodiment, the detection unit 302, the storage unit 303, and the auxiliary determination unit 304 of FIG. 5 are connected to the subsequent stage of the final determination unit. In this configuration, the final determination result, that is, the single circle in FIG. 10 is input to the detection unit 302 as the lower threshold L or higher and lower than the upper threshold H, and the double circle in FIG.

  The present invention suppresses false detection and improves detection capability for a steep and local change compared to a change in weather. In this respect, it is different from the techniques shown in Patent Documents 7 to 12 that prevent erroneous detection due to relatively slow or global changes such as weather. On the other hand, the technology of the present invention does not contradict the technology for preventing erroneous detection due to relatively slow changes in the weather and the like, and can be used in combination.

Claims (3)

Having a detection means and an arithmetic processing unit;
The detection means performs a detection operation on the obstacle detection area at a constant cycle, and outputs a detection signal.
The arithmetic processing unit includes:
Two detection thresholds, a lower threshold value and an upper threshold value, are input from the detection means for each cycle from the detection signal output by the detection means to the detection levels corresponding to the predetermined sections of the obstacle detection area. Detecting means for detecting a detection level of the detection signal to be detected;
Storage means for storing the detection results of the detection means in time series;
If the detection result in any section of the obstacle detection area in the current cycle is equal to or greater than the upper threshold, it is determined that there is an obstacle, and the detection result in any section in the obstacle detection area in the current cycle is lower. When the detection result of the same section of the obstacle detection area in the immediately preceding cycle is greater than or equal to the upper threshold or when the detection result of the same section of the obstacle detection area is A retroactive means, and if it is possible to reach the upper threshold or higher without going below the lower threshold, the determination means to continue the determination that there is an obstacle,
A crossing obstacle detection device characterized by comprising: In the crossing obstacle detection device according to claim 1,
The determination means, when the detection result of an arbitrary section of the obstacle detection area of the current cycle is equal to or higher than the lower threshold and lower than the upper threshold, the detection result of the section in the vicinity of the section of the obstacle detection area, If it is equal to or higher than the upper threshold in the immediately preceding cycle, or the detection results of the section in the obstacle detection area and the section in the vicinity of the section are retroactively time-sequentially, and pass below the lower threshold If it is possible to reach the upper threshold or higher, the determination that there is an obstacle is continued.
A crossing obstacle detection device characterized by that. In the crossing obstacle detection device according to claim 1 or 2,
The detection means starts the detection operation at the timing of raising the cutoff of the electric railroad crossing machine, performs the detection operation at a constant cycle, and stops the detection operation before the train arrives at the level crossing,
The determination means determines that there is an obstacle when the detection result of an arbitrary section of the obstacle detection area in the last cycle of the detection operation is equal to or higher than the upper threshold, and the obstacle in the last cycle of the detection operation When the detection result of an arbitrary section of the detection area is equal to or higher than the lower threshold and lower than the upper threshold, the detection result of the same section of the obstacle detection area in the immediately preceding cycle is equal to or higher than the upper threshold, or the obstacle The detection result of the same section of the detection area is retroactively traced in time series, and if it is possible to reach the upper threshold or higher without going through the lower threshold, the determination that there is an obstacle is continued.
A crossing obstacle detection device characterized by that.

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