JP7797895B2 - Fall detection device, fall detection system, fall detection method, and fall detection program - Google Patents

Description

The present invention relates to a fall detection device, a fall detection system, a fall detection method, and a fall detection program for detecting a person falling from a platform at a railway station.

At railway stations, passengers may accidentally fall from the platform onto the tracks. Also, when a train is stopped at a railway station, passengers may fall into the gap between the platform and the train. Conventionally, systems have been proposed that detect such falls onto the tracks and into the gap and notify relevant parties (such as dispatchers, station staff, conductors, or drivers).
For example, Patent Documents 1 and 2 disclose systems equipped with a laser scanner that emits a deflected laser to form a two-dimensional scanning range. The laser scanner is installed at a height below the platform and above the track, with the laser emitting the laser horizontally. Any area within the horizontal scanning range formed at that height is set as a monitoring area. The laser scanner detects whether an object is present in the monitoring area.

Japanese Patent Application Laid-Open No. 2014-095649 Japanese Patent Application Laid-Open No. 2007-038991

However, the above-described conventional platform fall detection system has the following problems.
In other words, the platform fall detection system disclosed in the above publication had the risk of falsely detecting not only people who have fallen, but also flying objects such as birds or plastic bags that have landed on the tracks, or animals that have entered the tracks.

In addition, track maintenance workers sometimes enter the tracks in the middle of the night, and in order to prevent false positives of people falling off, it is conceivable to shut down the system outside of railway operating hours. However, test vehicles and freight trains may be running at night, so if the system is shut down, it may not be possible to detect people who accidentally enter or fall onto the tracks, and danger may not be avoided before it occurs.

Furthermore, if the system is shut down in the middle of the night, there is a risk that operations will begin with the track fall detection system still stopped due to human error, such as forgetting to restart it or making a mistake in the restart operation.
The object of the present invention is to provide a fall detection device, a fall detection system, a fall detection method, and a fall detection program that can reliably detect falls when a train is approaching while suppressing the occurrence of false detections.

The fall detection device of the first invention is a fall detection device that detects a person who has fallen from a platform at a target station onto a track on which a train passes, and includes an object detection unit, a signal receiving unit, and a control unit. The object detection unit detects the intrusion of an object into a fall detection area set on the track. The signal receiving unit receives an approach signal indicating that a train is approaching the target station. When the signal receiving unit receives the approach signal, the control unit starts detecting the object using the object detection unit.

Here, when an approaching signal indicating an approaching train is received from the direction of the station (Station B) preceding the station (Station A) targeted for platform track fall monitoring, monitoring for track fall at Station A is initiated.
Here, the approach signal includes, for example, a track circuit signal that detects a train entering the previous station (Station B) or the previous previous station (Station C), a signal indicating that a train has passed between the previous station (Station B) and the target station (Station A), and a stop signal indicating that a train has stopped at the previous station (Station B).

This allows the time for monitoring falls on station platforms to be limited to when a train is approaching the station, without station staff having to operate the system, effectively reducing false alarms caused by flying objects such as birds or plastic bags that have landed on the tracks, or animals that have entered the tracks.
Furthermore, for example, when a track maintenance worker enters the tracks in the middle of the night, the fall detection system does not need to be stopped, as the system is not constantly functioning unless a train is approaching, preventing false alarms from being issued due to track maintenance workers entering the tracks. On the other hand, when test vehicles or freight trains are running at night, the fall detection system will automatically activate when the train approaches the station, so if a train approaches the station during track maintenance work, an alarm will be sounded, preventing danger before it occurs.

Furthermore, because there is no need to perform any operation to stop the fall detection system, it is possible to prevent the fall detection system from being stopped during railway company business hours due to forgetting to restart the system or making a mistake in restarting the system.In addition, it can flexibly respond to special schedules such as the New Year holidays and sudden disruptions to regular schedules, and the fall monitoring system can be automatically activated when necessary.
As a result, it is possible to accurately detect people falling onto the tracks, while significantly reducing the disruption to train operations caused by false alarms and the burden on staff.

The fall detection device of the second invention is the fall detection device of the first invention, wherein the signal receiving unit receives, as the approach signal, a track circuit signal indicating that a train is present at the station preceding the target station.
This means that when a track circuit signal indicating that a train has entered the station before the target station is received, it is possible to recognize that the train is approaching the target station, and control the system to begin detecting objects in the fall detection area.

A fall detection device according to a third aspect of the present invention is a fall detection device according to the first or second aspect of the present invention, wherein the signal receiving unit receives, as an approach signal, an entry detection signal indicating that a train has entered the station preceding the target station.
This means that when an entry detection signal indicating that a train has entered the station before the target station is received, it is possible to recognize that the train is approaching the target station, and control the system to begin detecting objects in the fall detection area.

A fall detection device according to a fourth invention is a fall detection device according to any one of the first to third inventions, wherein the signal receiving unit receives, as an approach signal, a departure detection signal indicating that a train has departed from a station preceding the target station.
This means that when a departure detection signal indicating that a train has departed from the station before the target station is received, it is possible to recognize that the train is approaching the target station, and control the system to begin detecting objects in the fall detection area.

A fall detection device according to a fifth aspect of the present invention is a fall detection device according to any one of the first to fourth aspects of the present invention, wherein the signal receiving unit receives, as an approach signal, a passing detection signal indicating that a train has passed between the target station and the previous station.
As a result, when a detection device installed between the target station and the previous station receives a passing detection signal indicating that a train has passed the location of the detection device, it can recognize that a train is approaching the target station, and can be controlled to begin detecting objects in the fall detection area.

A fall detection device according to a sixth invention is a fall detection device according to any one of the first to fifth inventions, wherein the signal receiving unit receives, as an approach signal, an entry detection signal indicating that a train has entered the station two stations before the target station.
This means that on lines where the distance between stations is short, when a track circuit signal indicating that a train has entered the station before the target station is received, it is possible to recognize that the train is approaching the target station, and control can be exercised to begin detecting objects in the fall detection area.

The fall detection device according to a seventh aspect of the present invention is the fall detection device according to any one of the first to sixth aspects of the present invention, further comprising an entry detection unit that detects when a train has entered a target station. When the entry detection unit detects that a train has entered the target station, the control unit stops object detection by the fall detection unit.

This allows the system to detect a train approaching the target station and start fall detection, and then stop fall detection when it detects that the train has entered the target station, so that detection of people falling onto the tracks can be carried out for only the minimum amount of time.
Therefore, since fall detection is not performed during the period from when the train enters the target station until it approaches the target station, it is possible to prevent the false detection of small animals such as dogs and cats or flying objects such as garbage as a fall.

A fall detection device according to an eighth aspect of the present invention is the fall detection device according to any one of the first to seventh aspects of the present invention, further comprising an exit detection unit that detects when a train has departed from a target station. When the exit detection unit detects that a train has departed from the target station, the control unit stops detection of the object by the fall detection unit.
This allows the system to detect a train approaching the target station and start fall detection, and then stop fall detection when it detects that the train has departed from the target station, thereby making it possible to detect people who have fallen onto the tracks for only the minimum amount of time.
Therefore, since fall detection is not performed during the period from when the train departs from the target station until when it approaches the target station, it is possible to prevent the false detection of small animals such as dogs and cats or flying objects such as garbage as a fall.

The fall detection device according to a ninth aspect of the present invention is the fall detection device according to any one of the first to eighth aspects of the present invention, further comprising a stop detection unit that detects that a train has stopped at a target station. When the stop detection unit detects that a train has stopped at the target station, the control unit stops the fall detection unit from detecting objects.

This allows the system to detect a train approaching a target station and start fall detection, and then stop fall detection when it detects that the train has stopped at the target station, thereby making it possible to detect people who have fallen onto the tracks for only the minimum amount of time.
Therefore, since fall detection is not performed during the period from when the train stops at the target station until it approaches the target station, it is possible to prevent the false detection of a fall due to small animals such as dogs and cats or flying objects such as garbage.

A fall detection device according to a tenth invention is a fall detection device according to any one of the first to ninth inventions, wherein the control unit controls the object detection unit to detect the intrusion of an object into a gap fall detection area, which detects falls into the gap between the platform and the train, when a train is stopped at a target station.
This allows the system to detect a train approaching a target station and start fall detection, and then when it detects that the train has stopped at the target station, it stops fall detection in the fall detection area on the track, while controlling it to start gap fall detection in the gap fall detection area set in the gap between the train and the platform, thereby detecting people who fall into the gap between the train and the platform and further improving safety.

The fall detection device of the eleventh invention is a fall detection device of any one of the first to tenth inventions, wherein the control unit changes the detectable size of an object detected by the object detection unit depending on the distance between a train approaching the target station and the target station.
This allows, for example, the detectable size for detection in the fall detection area to be set large when a train is located far from the target station, and the detectable size to be set small when the train is located close by. Therefore, when the train is located far from the target station, it is possible to avoid false detection of small animals, trash, etc., and to reliably detect a person who has fallen as the train approaches the target station.

A fall detection device according to a twelfth aspect of the present invention is a fall detection device according to the eleventh aspect of the present invention, wherein the control unit determines the detectable size based on a first threshold value when the distance between an approaching train and the target station is equal to or greater than a first distance, and determines the detectable size based on a second threshold value smaller than the first threshold value when the distance between the train and the target station is equal to or less than a second distance shorter than the first distance.

As a result, when a train is located at a distance greater than a first distance from the target station, the detectable size detected in the fall detection area is determined based on a first threshold value, and when the train approaches at a second distance or less that is shorter than the first distance, the detectable size is determined based on a second threshold value that is smaller than the first threshold value. Therefore, when the train is located far from the target station, false detection of small animals, trash, etc. can be avoided, while a fallen person can be reliably detected as the train approaches the target station.

A fall detection device according to a thirteenth aspect of the present invention is a fall detection device according to any one of the first to twelfth aspects of the present invention, wherein the control unit changes the detection time of an object detected by the object detection unit depending on the distance between a train approaching the target station and the target station.
This allows, for example, the detection time for detection in the fall detection area to be set longer when a train is located far from the target station, and shorter when the train is located closer. Therefore, when the train is located far from the target station, it is possible to avoid false detection of small animals, garbage, etc., and to reliably detect a person who has fallen as the train approaches the target station.

The fall detection system of the fourteenth invention comprises a fall detection device of any one of the first to thirteenth inventions, and an optical scanning unit that irradiates light onto a fall detection area and detects an object according to the intensity of the reflected light.
This makes it possible to configure a fall detection system that can accurately detect people falling onto the tracks, as described above, while significantly reducing the disruption to train operations caused by false alarms and the hassle placed on staff.

A fall detection method according to a fifteenth aspect of the present invention is a fall detection method for detecting a person who has fallen from a platform at a target station onto a track on which a train passes, and includes an object detection step, a signal reception step, and a control step. In the object detection step, an object is detected entering a fall detection area set on the track. In the signal reception step, an approach signal indicating that a train is approaching the target station is received. In the control step, upon receiving the approach signal in the signal reception step, object detection in the object detection step is initiated.

Here, when an approaching signal indicating an approaching train is received from the direction of the station (Station B) preceding the station (Station A) targeted for platform track fall monitoring, monitoring for track fall at Station A is initiated.
Here, the approach signal includes, for example, a track circuit signal that detects a train entering the previous station (Station B) or the previous previous station (Station C), a signal indicating that a train has passed between the previous station (Station B) and the target station (Station A), and a stop signal indicating that a train has stopped at the previous station (Station B).

This allows the time for monitoring falls on station platforms to be limited to when a train is approaching the station, without station staff having to operate the system, effectively reducing false alarms caused by flying objects such as birds or plastic bags that have landed on the tracks, or animals that have entered the tracks.
Furthermore, for example, when a track maintenance worker enters the tracks in the middle of the night, the fall detection system does not need to be stopped, as the system is not constantly functioning unless a train is approaching, preventing false alarms from being issued due to track maintenance workers entering the tracks. On the other hand, when test vehicles or freight trains are running at night, the fall detection system will automatically activate when the train approaches the station, so if a train approaches the station during track maintenance work, an alarm will be sounded, preventing danger before it occurs.

Furthermore, because there is no need to perform any operation to stop the fall detection system, it is possible to prevent the fall detection system from being stopped during railway company business hours due to forgetting to restart the system or making a mistake in restarting the system.In addition, it can flexibly respond to special schedules such as the New Year holidays and sudden disruptions to regular schedules, and the fall monitoring system can be automatically activated when necessary.
As a result, it is possible to accurately detect people falling onto the tracks, while significantly reducing the disruption to train operations caused by false alarms and the burden on staff.

A fall detection program according to a sixteenth aspect of the present invention is a fall detection program for detecting a person who has fallen from a platform at a target station onto a track on which a train passes, and causes a computer to execute a fall detection method including an object detection step, a signal reception step, and a control step. The object detection step detects the intrusion of an object into a fall detection area set on the track. The signal reception step receives an approach signal indicating that a train is approaching the target station. The control step starts object detection in the object detection step when the approach signal is received in the signal reception step.

Here, when an approaching signal indicating an approaching train is received from the direction of the station (Station B) preceding the station (Station A) targeted for platform track fall monitoring, monitoring for track fall at Station A is initiated.
Here, the approach signal includes, for example, a track circuit signal that detects a train entering the previous station (Station B) or the previous previous station (Station C), a signal indicating that a train has passed between the previous station (Station B) and the target station (Station A), and a stop signal indicating that a train has stopped at the previous station (Station B).

This allows the time for monitoring falls on station platforms to be limited to when a train is approaching the station, without station staff having to operate the system, effectively reducing false alarms caused by flying objects such as birds or plastic bags that have landed on the tracks, or animals that have entered the tracks.
Furthermore, for example, when a track maintenance worker enters the tracks in the middle of the night, the fall detection system does not need to be stopped, as the system is not constantly functioning unless a train is approaching, preventing false alarms from being issued due to track maintenance workers entering the tracks. On the other hand, when test vehicles or freight trains are running at night, the fall detection system will automatically activate when the train approaches the station, so if a train approaches the station during track maintenance work, an alarm will be sounded, preventing danger before it occurs.

Furthermore, because there is no need to perform any operations to stop the fall detection system, it is possible to prevent the fall detection system from being stopped during railway company business hours due to forgetting to restart the system or making a mistake in restarting the system. It can also flexibly respond to special schedules such as those around the New Year holidays, or sudden disruptions to regular schedules, and the fall monitoring system can be automatically activated when necessary.

As a result, it is possible to accurately detect when a person falls onto the tracks, while significantly reducing the disruption to train operations and the burden on staff caused by false alarms.

The fall detection device of the present invention operates the system only when a train is approaching, thereby reducing the occurrence of false detections and ensuring reliable fall detection when a train is approaching.

1 is a system diagram showing the configuration of a fall detection system that detects falls onto tracks at a target station according to one embodiment of the present invention. FIG. 2 is a control block diagram showing the configuration of a fall detection device included in the fall detection system of FIG. 1 . 1A is a plan view showing the scanning range of an optical scanner when there is no train on the station platform, and FIG. 1B is a plan view showing the scanning range of an optical scanner when there is a train on the station platform. A cross-sectional view from the direction of train travel showing the relative positions of an optical scanner installed in the space below a station platform and a train stopped at the station. 1A is a perspective view showing a fall detection area when there is no train on the station platform, and FIG. 1B is a perspective view showing a gap fall detection area when there is a train on the station platform. 2 is a sensing chart for switching on and off the fall detection device in the fall detection system of FIG. 1 . FIG. 10 is a control block diagram showing the configuration of a fall detection device according to another embodiment of the present invention. 8 is a sensing chart showing an example of control for switching on and off the fall detection device of FIG. 7;

(Embodiment 1)
A fall detection system 1 including a fall detection device 4 according to one embodiment of the present invention will be described below with reference to FIGS. 1 to 6. FIG.
In the present embodiment, more detailed explanation than necessary may be omitted. For example, detailed explanation of well-known matters or redundant explanation of substantially the same configuration may be omitted. This is to avoid unnecessary redundancy in the following explanation and to facilitate understanding by those skilled in the art.

Furthermore, the applicant provides the accompanying drawings and the following description to enable those skilled in the art to fully understand the present invention, and they are not intended to limit the subject matter described in the claims.
In the following description, the "longitudinal direction" refers to the longitudinal direction of the platform P of the railway station (the left-right direction on the paper in FIG. 3 and the direction perpendicular to the paper in FIG. 4). The longitudinal direction is approximately parallel to the extension direction of the track R adjacent to the platform P and the length direction of the vehicle C on the track R. The "width direction" refers to the width direction of the platform P (the up-down direction on the paper in FIG. 3 and the left-right direction on the paper in FIG. 4). The width direction is approximately parallel to the gauge direction of the track R adjacent to the platform P and the width direction of the vehicle C on the track R. The "inner side" or "inner side" in the width direction refers to the side or direction approaching the width center of the platform P. The "outer side" or "outward side" in the width direction refers to the side or direction away from the width center of the platform P.

The track R includes a track bed and a pair of rails installed thereon. A train T runs on the track R along the rails. The train T is made up of one car C, or is made up of two or more cars C connected in sequence via couplers. The platform P is set adjacent to the track R in the width direction, and its upper surface is located above the track R.
The states of the track R include an "unattended state" shown in FIG. 3( a) and an "on-track state" shown in FIG. 3( b). In the unattended state, no train T is present on the track R, and the space above the track R is wide open. In the unattended state, railway passengers wait for the arrival of the train T on the upper surface of the platform P. In the on-track state, the train T is stopped on the track R. In the on-track state, railway passengers straddle the gap D formed between the platform P and the train T to board the train T from the upper surface of the platform P or disembark from the train T onto the upper surface of the platform P.
In this embodiment, Station A shown in FIG. 1 is a target station where track fall detection is performed, and Station B indicates the station immediately preceding the direction of travel of a train entering Station A.

(1) Configuration of the fall detection system 1 The fall detection system 1 according to this embodiment is applied to a railway station equipped with a platform P, and detects railway passengers who accidentally fall from the platform P. The detection targets are both "passengers who fall off the track" who fall from the platform P to the track R while an unattended passenger is present, and "passengers who fall through the gap" who fall into the gap D while an unattended passenger is present on the track. Some gap passengers fall to the track R, while others become trapped in the gap D and become suspended in mid-air, and both of these are detection targets.

The state of the track R includes an "in-track state" as a transition state from an unoccupied state to an occupied state, and an "out-track state" as a transition state from an occupied state to an unoccupied state.
As shown in Figure 1, the fall detection system 1 of this embodiment includes a station A track circuit 2a that detects the presence or absence of a train at a station (station A) that is subject to track fall monitoring, a scanning device (optical scanning unit) 3 installed in the space below the platform P, a fall detection device 4 connected to the scanning device 3, an alarm device 5 that issues an alarm based on the detection result of the fall detection device 4, and a memory device 6.

The Station A track circuit 2a detects the presence or absence of a train at the station (Station A) that is subject to track fall monitoring, and transmits a track circuit signal to the fall detection device 4. As an example, the Station A track circuit 2a may be a track circuit whose detection range is the platform P and the adjacent track R. The Station A track circuit 2a may be installed on the roof at both longitudinal ends of the platform P and may be composed of vehicle detection sensors that detect the presence or absence of the top or side of a vehicle C.

In addition, the scanning device 3 of the station A track circuit 2a may have the function of the station A track circuit. In the on-track state (and transient state), the vehicle C is within the scanning range SR of the scanning device 3. Therefore, the detection results of each scanning device 3 can be used to determine the state of the track.
The control for terminating the track fall monitoring by the fall detection device 4 that receives the track circuit signal from the A station track circuit 2a will be described in detail later.

As shown in Figures 2 to 4, the scanning device 3 is installed in the space below the platform P along the track R adjacent to the platform P, and has multiple scanner units 3a, 3b, and 3c. Each scanner unit 3a, 3b, and 3c includes a pair of scanners 31 and 32 arranged above and below. The multiple scanner units 3a, 3b, and 3c are installed at multiple installation positions spaced apart in the longitudinal direction.

The scanners 31 and 32 are, for example, 2D laser scanners that scan laser light within a predetermined angular range, and as shown in FIG. 2, have a light emitting unit 33, a deflecting unit 34, a light receiving unit 35, and a detecting unit 36.
The light emitting unit 33 emits a scanning light SL such as a laser beam.
The deflection unit 34 has a deflector such as a galvanometer mirror and an actuator that rotates the deflector. The scanning light SL emitted by the light-emitting unit 33 is deflected by the deflection unit 34 and then emitted. This forms a two-dimensional scanning range SR. If an object is present within the scanning range SR, the scanning light SL is reflected by the object.

The light receiving section 35 receives the reflected light of the scanning light SL.
The detection unit 36 detects whether or not an object is present in the scanning range SR (or more specifically, a monitoring area set within the scanning range SR) based on the intensity of the reflected light received by the light receiving unit 35.
4, the scanners 31 and 32 are installed below the platform P and above the track R. The upper scanner 31 is installed above the lower scanner 32.

The lower scanner 32 primarily detects people who have fallen off the tracks. Additionally, the lower scanner 32 may also detect the wheels W of the vehicle C supported on the rails when the vehicle is on the track. On the other hand, the lower scanner 32 is not required to detect components of the track R. The vertical position of the lower scanner 32 is adjusted to an appropriate value (for example, approximately 250 mm above the track) to perform this role.

The upper scanner 31 primarily detects people who have fallen through gaps and become suspended in the air in gap D. The vertical position of the upper scanner 31 is adjusted to an appropriate value for performing this function (for example, approximately 700 mm above the track, or approximately 600 mm below platform P). As will be described later, the upper scanner 31 of this embodiment is used not only for its original purpose of detecting people who have fallen through gaps, but also to accurately detect people who have fallen onto the track when no one is present.

Scanners 31 and 32 are installed widthwise inward of track R and further widthwise inward of the edge of platform P. A space may be formed below platform P, recessed widthwise inward from the edge of platform P. Scanner units 3a, 3b, and 3c are installed, for example, within such a space, and the vertical and widthwise positions of scanners 31 and 32 are adjusted within this space.

The scanners 31 and 32 are installed in a position where the scanning light SL is emitted horizontally outward in the width direction and deflected within a horizontal plane, so that the scanners 31 and 32 form two horizontal scanning ranges SR below the platform P and outward in the width direction as viewed from the scanners 31 and 32.
3, the deflection range of the scanning light SL is set to an angular range of approximately −5° to 185°. In a plan view, the scanning range SR is formed in a semicircular shape that is line-symmetrical with respect to a reference line RL that extends in the width direction from the corresponding scanner 31, 32. The multiple scanning ranges SR are formed by the multiple scanner units 3a, 3b, and 3c, and are aligned in the longitudinal direction and partially overlap each other.

A monitoring area is set within each scanning range SR. Each scanner 31, 32 can detect the presence or absence of an object within the scanning range SR. When each scanner 31, 32 detects the presence of an object within the set monitoring area, it outputs a detection signal indicating this.
The size and location of the monitoring area are changed depending on the state of the track. The scanners 31 and 32 according to this embodiment can simultaneously set multiple monitoring areas in different regions within the same scanning range SR. Furthermore, two or more monitoring areas that are simultaneously set can partially overlap each other within the same scanning range SR.

In this embodiment, the scanner units 3 a, 3 b, and 3 c are installed at intervals corresponding to the length of two cars in the longitudinal direction, and are positioned so as to face the car couplings of the stopped train T in the width direction.
Scanner unit 3a, installed at the end on one longitudinal side (the left side of the paper in FIG. 3), faces the coupling portion of the first and second cars. Scanner unit 3b, installed next to it, is separated from the end scanner unit 3a by the length of two cars and faces the coupling portion of the third and fourth cars.

The monitoring area set for each scanner 31, 32 has a length equivalent to that of two cars in the longitudinal direction, and corresponds to the area in which two cars, a car C on one side in the longitudinal direction and a car C on the other side (the right side of the paper in FIG. 3 ), are stopped when viewed from the installation position.
The plurality of monitoring areas set in the plurality of scanner units 3a, 3b, and 3c are aligned in the longitudinal direction, so that the entire area where the train T stops is monitored.

However, the number of scanner units 3 a, 3 b, and 3 c may be one or more, and is not particularly limited. The number of scanner units 3 a, 3 b, and 3 c can be changed appropriately depending on the longitudinal dimension of the monitoring area, the effective length of the platform P, and the maximum length of the train T that is expected to stop on the track R.
2, the fall detection device 4 is connected to the A station track circuit 2a and the scanning device 3, and detects a person falling from the platform P based on the detection results output from the A station track circuit 2a and the scanning device 3. When the fall detection device 4 detects a person falling, it causes the alarm device 5 to issue an alert to notify relevant people.

As shown in Figure 1, the fall detection device 4 of this embodiment is connected to the B station track circuit 2b, which detects the presence or absence of a train at the station (B station) preceding the station (A station) that is the target station for track fall monitoring, and starts track fall monitoring when it receives a train approach signal from the B station track circuit 2b.
The control of receiving a train approach signal and starting the process of monitoring for track falls will be described in detail later.

The warning device 5 includes an alarm installed in a control center that manages train operations and issues a warning to the commander. It also includes an alarm installed in a railway station and issues a warning to station staff. It also includes an alarm installed in the control car of train T and issues a warning to the driver or conductor. The alarm may be a speaker or buzzer that outputs sound information such as a warning sound, a display that displays a warning message, or a lamp that emits a warning light.

Based on the alarm, relevant personnel can take measures to deal with the fall and prevent secondary accidents associated with the fall. If a foreign object other than a fallen person is mistakenly detected as a fallen person and an alarm is erroneously issued, the response efforts of relevant personnel will be in vain and there is a possibility that train schedules will be disrupted. As described below, the fall detection system 1 according to this embodiment can reduce false detections compared to conventional systems by effectively utilizing the monitoring areas set in the pair of upper and lower scanners 31, 32. This also reduces false alarms, supporting smooth train operation.
The storage device 6 is connected to the fall detection device 4 and stores log data such as fall detection results.

(2) Fall detection device 4
The fall detection device 4 is, for example, configured by a computer including a CPU, memories such as ROM, RAM, and EEPROM, and an input/output interface. The computer may be a single computer or a combination of multiple physically distributed computers. The memory stores a fall detection program for causing such a computer to execute the fall detection method. The CPU reads the fall detection program stored in the memory and performs information processing related to the fall detection method in accordance with the fall detection program. In addition to the fall detection program, the memory can also temporarily store information or data required for executing the fall detection method.

The fall detection device 4 has a control unit 10, a signal receiving unit 11, a trajectory information acquisition unit 12, a monitoring area setting unit 13, a scanning data acquisition unit 14, a fall detection unit 15, an output unit 16 and a timer 17, which are implemented by the CPU reading and executing a fall detection program.
The control unit 10 is connected to the signal receiving unit 11, the track information acquiring unit 12, the monitoring area setting unit 13, the scan data acquiring unit 14, the fall detecting unit 15, the output unit 16 and the timer 17, and controls each unit.

The signal receiving unit 11 receives an approach signal from the station B track circuit 2b, which is the station before station A, which is the station to be monitored for track fall, indicating the state of the track at station B, i.e., the train entering or leaving the station or the stopped state at station B.
The approach signal indicates that a train is approaching Station A. The fall detection device 4 receives this approach signal and starts the process of monitoring for track falls, which will be described later.

The track information acquisition unit 12 acquires information indicating the state of the track. When the Station A track circuit 2a detects the state of the track, the track information acquisition unit 12 may acquire the detection results from the Station A track circuit 2a. The track information acquisition unit 12 may also acquire information indicating the state of the track itself by determining the state of the track based on the detection results from the Station A track circuit 2a. In this embodiment, the track information acquisition unit 12 acquires information indicating whether the state of the track is a presence state, an absence state, or neither of these two states (a transient state).

The monitoring area setting unit 13 selects one monitoring area from a predetermined pattern to be set for each scanner 31, 32, depending on the acquired track condition or type of approach signal, and sets the monitoring area of the selected pattern for each scanner 31, 32. The monitoring area setting unit 13 switches the monitoring area pattern, the detection target of the fall detection system 1, or the operating mode of the fall detection system 1, depending on the track condition.

The scan data acquisition unit 14 acquires the detection results output by the scanner units 3a to 3c (scanners 31, 32) regarding the presence or absence of an object within the monitoring area.
The fall detection unit 15 determines whether or not a person has fallen from the platform P based on the detection results acquired by the scan data acquisition unit 14 and in accordance with a predetermined determination logic.
When the fall detection unit 15 detects a person who has fallen, the output unit 16 outputs a command to the alarm device 5 to perform an alarm operation.
The timer 17 is provided to count a preset time for performing fall detection, and transmits the elapsed time from the start of fall detection to the control unit 10 .

(monitoring area)
In the fall detection device 4 of this embodiment, as shown in Figure 3, the monitoring area patterns that are selectively set in the scanning device 3 depending on the state of the track are a track monitoring area AR, which is a pattern that is set when no train is present, and a gap monitoring area AD, which is a pattern that is set when a train is present on the track.

As shown in Figure 3(a), the track monitoring area AR is set to cover the space above the track R. A person who falls off the track will enter the track monitoring area AR during the process of falling. Therefore, based on the detection result that an object is present in the track monitoring area AR, it is possible to detect the person who has fallen off the track across the entire width of the track R.
As shown in Figure 3(b), the gap monitoring area AD is narrower in width than the track monitoring area AR and is set within the gap D. A person who falls through the gap and reaches the track R will enter the gap monitoring area AD during the fall. A person who becomes suspended in mid-air will also remain within the gap monitoring area AD (particularly the upper gap monitoring area ADU). Therefore, a person who falls through the gap can be detected based on the detection result that an object is present within the gap monitoring area AD.

(Trajectory monitoring area)
The scanning device 3 is composed of a plurality of scanner units 3a, 3b, and 3c arranged in the longitudinal direction.
As shown in FIG. 3(a), the track monitoring area AR is formed by connecting track monitoring areas ARa, ARb, and ARc set for the plurality of scanner units 3a, 3b, and 3c in the longitudinal direction.

As described above, each of the scanner units 3a, 3b, and 3c is composed of a pair of upper and lower scanners 31 and 32.
The track monitoring area ARa of the scanner unit 3a is made up of an upper track monitoring area ARaU set in the upper scanner 31 and a lower track monitoring area ARaL set in the lower scanner 32. The same applies to the track monitoring areas ARb and ARc of the other scanner units 3b and 3c.

That is, a plurality of upper scanners 31 are arranged along the longitudinal direction, and a plurality of lower scanners 32 are arranged along the longitudinal direction. The track monitoring area AR of the scanning device 3 is made up of an upper track monitoring area ARU and a lower track monitoring area ARL.
The upper track monitoring area ARU is formed by longitudinally connecting a plurality of upper track monitoring areas ARaU, ARbU, ARcU set on a plurality of upper scanners 31. The lower track monitoring area ARL is set at a position lower than the upper track monitoring area ARU, and is formed by longitudinally connecting a plurality of lower track monitoring areas ARaL, ARbL, ARcL set on a plurality of lower scanners 32.

The upper track monitoring area ARU of the scanning device 3, or the upper track monitoring areas ARaU, ARbU, and ARcU of the upper scanner 31 that constitute it, are an example of a "first monitoring area." The lower track monitoring area ARL of the scanning device 3, or the lower track monitoring areas ARaL, ARbL, and ARcL of the lower scanner 32 that constitute it, are an example of a "second monitoring area" that is set at a lower position than the first monitoring area.

The multiple upper track monitoring areas ARaU, ARbU, and ARcU (multiple first monitoring areas) are set to be aligned longitudinally. Furthermore, the multiple lower track monitoring areas ARaL, ARbL, and ARcL (multiple second monitoring areas) are set to correspond to the multiple upper track monitoring areas ARaU, ARbU, and ARcU, respectively. Each lower track monitoring area ARaL, ARbL, and ARcL is set at approximately the same longitudinal position as the corresponding upper track monitoring area ARaU, ARbU, and ARcU.

Figure 5(a) is a perspective view showing the track monitoring area ARa set by the scanner unit 3a when no trains are present. In this embodiment, the upper track monitoring area ARaU is formed by longitudinally connecting multiple upper segments ARaU1, ARaU2, ARaU3, and ARaU4 set within a single scanning range SR formed by the upper scanner 31 of the scanner unit 3a. The lower track monitoring area ARaL is also formed by longitudinally connecting multiple lower segments ARaL1, ARaL2, ARaL3, and ARaL4 set within a single scanning range SR formed by the lower scanner 32 of the scanner unit 3a.

In this way, multiple upper segments ARaU1, ARaU2, ARaU3, and ARaU4 (multiple first monitoring areas) are set to be aligned in the longitudinal direction. Furthermore, multiple lower segments ARaL1, ARaL2, ARaL3, and ARaL4 (multiple second monitoring areas) are set to correspond to the multiple upper segments ARaU1, ARaU2, ARaU3, and ARaU4, respectively. Each lower segment ARaL1, ARaL2, ARaL3, and ARaL4 is set at approximately the same position in the longitudinal direction as the corresponding upper segment ARaU1, ARaU2, ARaU3, and ARaU4.

The same applies to the other scanner units 3b and 3c. The number of segments may be set to any number as long as it is the same for the top and bottom of each scanner unit. In this embodiment, as a mere example, the number of segments is four for each of the scanner units 3a, 3b, and 3c.
As an example, the upper segments ARaU1, ARaU2, ARaU3, and ARaU4 are formed by equally dividing the upper track monitoring area ARaU in the longitudinal direction. In this example, the upper track monitoring area ARaU is rectangular with its long side extending longitudinally, and the length of the long side is the length of two railcars (approximately 40 m). The upper segments ARaU1, ARaU2, ARaU3, and ARaU4 are also roughly rectangular in plan view, with the length of their long sides roughly equal to half the length of a railcar. The same applies to the lower segments ARaL1, ARaL2, ARaL3, and ARaL4.

(Gap monitoring area)
The gap monitoring area AD is similar to the track monitoring area AR. The gap monitoring area AD is formed by connecting gap monitoring areas ADa, ADb, and ADc set for the plurality of scanner units 3a, 3b, and 3c in the longitudinal direction.
The gap monitoring area ADa of the scanner unit 3a is composed of an upper gap monitoring area ADaU set in the upper scanner 31 and a lower gap monitoring area ADaL set in the lower scanner 32. The same applies to the gap monitoring areas ADb, ADc of the other scanner units 3b, 3c. The gap monitoring area AD of the scanning device 3 is composed of an upper gap monitoring area ADU and a lower gap monitoring area ADL. The upper gap monitoring area ADU is formed by longitudinally connecting multiple upper gap monitoring areas ADaU, ADbU, ADcU set in multiple upper scanners 31. The lower gap monitoring area ADL is set at a lower position than the upper gap monitoring area ADU, and is formed by longitudinally connecting multiple lower gap monitoring areas ADaL, ADbL, ADcL set in multiple lower scanners 32.

Multiple upper gap monitoring areas ADaU, ADbU, ADcU (multiple first monitoring areas) are set up so that they are aligned in the longitudinal direction. Additionally, multiple lower gap monitoring areas ADaL, ADbL, ADcL (multiple second monitoring areas) are set up so that they correspond to the multiple upper gap monitoring areas ADaU, ADbU, ADcU, respectively. Each lower gap monitoring area ADaL, ADbL, ADcL is set up at approximately the same position in the longitudinal direction as the corresponding upper gap monitoring area ADaU, ADbU, ADcU.

Figure 5(b) is a perspective view showing the gap monitoring area ADa set by the scanner unit 3a when the train is on track. In this embodiment, as a mere example, the gap monitoring area ADa of the scanner unit 3a is not subdivided into multiple segments, unlike the track monitoring area ARa (see Figure 5(a)). However, the multiple upper gap monitoring areas ADaU, ADbU, and ADcU may partially overlap each other. Correspondingly, the multiple lower gap monitoring areas ADaL, ADbL, and ADcL may also partially overlap each other.

<Start and end process of track fall monitoring by fall detection device 4>
In the fall detection device 4 of this embodiment, as shown in Figure 1, the start and end of detection of a person who has fallen onto the track at a station (Station A) that is subject to track fall monitoring is controlled by receiving an approach signal that indicates the approach of a train to Station A, received from the station previous to Station A (Station B).
Specifically, in the fall detection device 4, as shown in Figure 2, when the signal receiving unit 11 receives a track circuit signal from station B as an approach signal, the control unit 10 determines that a train will arrive at station A in a few minutes and controls the fall detection unit 15 to start monitoring for track falls.

More specifically, as shown in FIG. 6, when the signal receiving unit 11 receives a track circuit signal (approach signal) indicating that a train is present on the platform at station B, the control unit 10 controls the fall detection unit 15 to start monitoring for track falls.
That is, when the fall detection device 4 receives a track circuit ON signal (entry start signal) from Station B, it starts monitoring for track falls at Station A.

In addition, if the distance between Station A and Station B is large enough that it takes a sufficient amount of time for a train departing Station B to enter Station A, the fall detection unit 15 may be controlled to start monitoring for track fall when it receives a track circuit signal OFF signal (departure completion signal) indicating the train's departure at Station B as shown in Figure 6.
In addition, in the fall detection device 4, after starting track fall monitoring, as shown in FIG. 2, when the track information acquisition unit 12 receives a track circuit ON signal from the A station track circuit 2a, which indicates that a train is entering the station A, the control unit 10 controls the fall detection unit 15 to end track fall monitoring.

In addition, when the fall detection device 4 detects that the train has stopped at Station A, the control unit 10 controls the fall detection unit 15 to start gap fall monitoring to detect falls into the gap between the platform and the vehicle.
Then, in the fall detection device 4, when the track information acquisition unit 12 receives the A station track circuit OFF signal (outgoing line completion signal), it controls the fall detection unit 15 to end gap fall monitoring.

<Main features>
The fall detection device 4 of this embodiment is a device that detects a person who has fallen from a platform at a target station onto a track on which a train passes, and includes a fall detection unit 15, a signal receiving unit 11, and a control unit 10. The fall detection unit 15 detects the intrusion of an object into a fall detection area set on the track. The signal receiving unit 11 receives an approach signal that indicates the approach of a train to the target station. When the signal receiving unit 11 receives the approach signal, the control unit 10 starts detecting the object in the fall detection unit 15.

This allows the time for monitoring falls on station platforms to be limited to when a train is approaching the station, without station staff having to operate the system, effectively reducing false alarms caused by flying objects such as birds or plastic bags that have landed on the tracks, or animals that have entered the tracks.
Furthermore, for example, when a track maintenance worker enters the tracks in the middle of the night, the fall detection system does not need to be stopped, as the system is not constantly functioning unless a train is approaching, preventing false alarms from being issued due to track maintenance workers entering the tracks. On the other hand, when test vehicles or freight trains are running at night, the fall detection system will automatically activate when the train approaches the station, so if a train approaches the station during track maintenance work, an alarm will be sounded, preventing danger before it occurs.

Furthermore, because there is no need to perform any operation to stop the fall detection system, it is possible to prevent the fall detection system from being stopped during railway company business hours due to forgetting to restart the system or making a mistake in restarting the system.In addition, it can flexibly respond to special schedules such as the New Year holidays and sudden disruptions to regular schedules, and the fall monitoring system can be automatically activated when necessary.
As a result, it is possible to accurately detect people falling onto the tracks, while significantly reducing the disruption to train operations caused by false alarms and the burden on staff.

(Embodiment 2)
A fall detection system 1 including a fall detection device 4 according to another embodiment of the present invention will be described below with reference to FIGS. 7 and 8. FIG.

The fall detection system 1 of this embodiment differs from the first embodiment in that, as shown in Figure 7, it receives approach signals indicating that a train is approaching from the station (Station B) before the station (Station C) before the station targeted for track fall detection monitoring (Station A), and initiates the fall detection process by the fall detection device 4.
However, since the system configuration and device configuration are the same as those in the first embodiment, the same reference numerals are used here and detailed description of each component is omitted.

That is, in this embodiment, as shown in FIG. 7, the fall detection device 4 receives approach signals from the station B track circuit 2b at the station B before the station (station B) that is the target station for track fall detection monitoring (station A) and the station C track circuit 2c at the station two before that (station C), and controls the fall detection unit 15 to start monitoring for track falls.
The approach signal received by the fall detection device 4 may be a track circuit ON signal indicating that trains are on the tracks to Station B and Station C, or a track circuit OFF signal indicating that trains are departing from the tracks.

In the fall detection device 4 of this embodiment, the control unit 10 controls the fall detection unit 15 to start monitoring for track falls when the signal receiving unit 11 receives a track circuit signal (approach signal) indicating that a train is present on the platform at Station C, as shown in Figure 8.
That is, when the fall detection device 4 receives a track circuit ON signal (entry start signal) from Station C, it starts monitoring for track falls at Station A.

In addition, if the distance between Station A and Station C is large enough that it takes a sufficient amount of time for a train departing Station C to enter Station A, the fall detection unit 15 may be controlled to start monitoring for track fall when it receives a track circuit signal OFF signal (departure completion signal) indicating the departure of the train at Station C shown in Figure 8.
Here, when the fall detection device 4 receives an approach signal (track circuit signal, etc.) from Station C and controls the fall detection unit 15 to start monitoring for track falls, the control unit 10 sets the size S1 of an object that can be detected in the fall detection area and the detection time T1.

Next, in the fall detection device 4, as shown in Figure 8, when the signal receiving unit 11 receives a track circuit signal (approach signal) indicating that a train is present on the platform at station B, the control unit 10 switches the size of the object that can be detected by track fall monitoring from S1 to S2 (S2 < S1), and switches the detection time from T1 to T2 (T2 < T1).
That is, when the fall detection device 4 receives a track circuit ON signal (entry start signal) from station B, which is closer to station A than station C, it switches the detectable size and detection time for monitoring track falls at station A.

Here, the detectable sizes S1 and S2 are set when an approach signal is received from station C, which is farther away from station A than station B. The detectable size S1 is larger than the detectable size S2, which is set when an approach signal is received from station B.
This makes it possible to avoid false detection of small animals, garbage, etc. when the train is far from station A (such as when it has passed station C), and as the train approaches station A (such as when it has passed station B), the detectable size is switched so that even small objects can be detected, thereby ensuring that people who have fallen off the train are detected.

Furthermore, the detection times T1 and T2 are set at the timing when an approach signal is received from station C, which is farther away from station A than station B, and the detection time T1 is longer than the detection time T2, which is set at the timing when an approach signal is received from station B.
As a result, when the train is far from station A (such as when it has passed station C), the detection time can be set long, making it possible to detect only objects that have remained in the fall detection area for a long time, thereby avoiding erroneous detection of small animals, trash, etc. Then, as the train approaches station A (such as when it has passed station B), the detection time can be set short, making it possible to reliably detect a person who has fallen.

Furthermore, in the fall detection device 4, as in the above-described first embodiment, after starting track fall monitoring, when the track information acquisition unit 12 receives a track circuit ON signal from the A station track circuit 2a, which indicates that a train is entering the station A, the control unit 10 controls the fall detection unit 15 to end track fall monitoring.
In addition, in the fall detection device 4, as in the above embodiment 1, when it detects that the train has stopped at Station A, the control unit 10 controls the fall detection unit 15 to start gap fall monitoring to detect falls into the gap between the platform and the vehicle.
Then, in the fall detection device 4, when the track information acquisition unit 12 receives the A station track circuit OFF signal (outgoing line completion signal), it controls the fall detection unit 15 to end gap fall monitoring.

Other Embodiments
Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the gist of the invention.

(A)
In the above embodiment, the present invention has been described as being implemented as a fall detection device and a fall detection method, but the present invention is not limited to this.
For example, the present invention may be realized as a fall detection program that causes a computer to execute the above-described fall detection method.

This fall detection program is stored in a memory (storage unit) installed in the fall detection device, and the CPU reads the fall detection program stored in the memory and causes the hardware to execute each step. More specifically, the CPU reads the fall detection program and executes the object detection step, signal reception step, and control step described above, thereby achieving the same effects as those described above.
The present invention may also be realized as a recording medium storing a fall detection program.

(B)
In the above embodiment, an example has been described in which a track circuit signal (approach signal) is received from the station (Station B) before the target station (Station A) where track fall monitoring is performed, or from the station (Station C) before that, and control is performed to start track fall monitoring. However, the present invention is not limited to this.
For example, if the target station (Station A) where track fall monitoring is to be performed is far enough away from the previous station (Station B), control may be implemented to start track fall monitoring upon receiving a passing signal indicating that a track circuit signal installed between Station A and Station B has been turned ON.

(C)
In the above embodiment, an example has been described in which the control unit 10 controls the fall detection unit 15 to end track fall monitoring when the track information acquisition unit 12 receives a track circuit ON signal (entry start signal) from the A station track circuit 2a, indicating that a train is entering the A station. However, the present invention is not limited to this.
For example, when a track circuit OFF signal (departure start signal) indicating that the train is leaving for Station A is received, control may be performed to end the track fall monitoring.

(D)
In the above embodiment, an example has been described in which the scanning device 3 that monitors for track slides is configured by disposing scanner units 3a, 3b, and 3c, each including a pair of upper and lower scanners 31 and 32, along the longitudinal direction of the platform. However, the present invention is not limited to this.
For example, the number of scanners arranged along the platform is not limited to three, and any appropriate number may be installed depending on the length of the train and the length of the platform.
Furthermore, the scanners do not need to be provided in pairs, one above the other; for example, if only detection of a person falling onto the track is to be performed, only the lower scanner may be provided.

(E)
In the above-described second embodiment, an example has been described in which the control unit 10 controls the system to start monitoring for track fall at station A when it receives an approach signal (track circuit signal) from station C, which is located before station A, and controls the system to reduce the detectable size and shorten the detection time for track fall monitoring at station A when it receives an approach signal (track circuit signal) from station B, which is located before station A. However, the present invention is not limited to this.

For example, when an approach signal is received from station C, control may be exercised to start monitoring for track fall at station A, and when an approach signal is received from station B, control may be exercised to reduce only the detectable size of the track fall monitoring at station A.
Alternatively, when an approach signal is received from station C, control may be exercised to start monitoring for track fall at station A, and when an approach signal is received from station B, control may be exercised to shorten only the detection time for monitoring for track fall at station A.

The fall detection device of the present invention operates the system only when a train is approaching, thereby reducing the occurrence of false detections and ensuring reliable fall detection when a train is approaching. Therefore, it can be widely applied to systems installed at railway company stations.

1 Fall detection system 2a Station A track circuit 2b Station B track circuit 2c Station C track circuit 3 Scanning device (optical scanning unit)
3a, 3b, 3c Scanner unit 4 Fall detection device 5 Alarm device 6 Storage device 10 Control unit 11 Signal receiving unit 12 Track information acquisition unit (entry detection unit, departure detection unit)
13 Monitoring area setting unit 14 Scan data acquisition unit 15 Fall detection unit (object detection unit)
16 Output unit 17 Timer 31 Upper scanner 32 Lower scanner 33 Light emitting unit 34 Polarizing unit 35 Light receiving unit 36 Detection unit AD Gap monitoring area AR Track monitoring area C Vehicle D Gap P Platform R Track SR Scanning range S1, S2 Detectable size T Train T1, T2 Detection time

Claims (16)

A fall detection device that detects a person who has fallen from a platform at a target station onto a track on which a train passes,
an object detection unit that detects an object entering a fall detection area set on the track;
a signal receiving unit that receives an approach signal indicating an approach of a train to the target station as a result of the detection of a train at a station before the target station ;
a control unit that starts detecting the object in the object detection unit when the signal receiving unit receives the approach signal;
A fall detection device comprising: The signal receiving unit receives, as the approach signal, a track circuit signal indicating that a train is present at a station preceding the target station.
The fall detection device according to claim 1 . The signal receiving unit receives, as the approach signal, a train entry detection signal indicating that a train has entered a station preceding the target station.
The fall detection device according to claim 1 or 2. the signal receiving unit receives, as the approach signal, a departure detection signal indicating that a train has departed from a station preceding the target station;
The fall detection device according to any one of claims 1 to 3. The signal receiving unit receives, as the approach signal, a passage detection signal indicating that a train has passed between the target station and the previous station.
The fall detection device according to any one of claims 1 to 4. The signal receiving unit receives, as the approach signal, a train entry detection signal indicating that a train has entered a station two stations before the target station.
The fall detection device according to any one of claims 1 to 5. Further provided is an entry detection unit that detects that a train has entered the target station,
When the train entry detection unit detects that a train has entered the target station, the control unit stops the detection of the object by the object detection unit.
The fall detection device according to any one of claims 1 to 6. Further provided is a departure detection unit that detects that a train has departed from the target station,
the control unit, when the outgoing track detection unit detects that a train has departed from the target station, stops detection of the object by the object detection unit.
The fall detection device according to any one of claims 1 to 7. Further, a stop detection unit is provided to detect that the train has stopped at the target station,
When the stop detection unit detects that the train has stopped at the target station, the control unit stops the detection of the object by the object detection unit.
A fall detection device according to any one of claims 1 to 8. the control unit controls the object detection unit to detect an intrusion of an object into a gap fall detection area that detects an object falling into a gap between the platform and the train while the train is stopped at the target station.
The fall detection device according to any one of claims 1 to 9. the control unit changes the detectable size of the object detected by the object detection unit according to the distance between the train approaching the target station and the target station.
The fall detection device according to any one of claims 1 to 10. The control unit determines the detectable size based on a first threshold value when the distance between the train approaching the target station and the target station is equal to or greater than a first distance, and determines the detectable size based on a second threshold value smaller than the first threshold value when the distance between the train and the target station is equal to or less than a second distance shorter than the first distance.
The fall detection device according to claim 11. The control unit changes a detection time of the object detected by the object detection unit according to a distance between the train approaching the target station and the target station.
A fall detection device according to any one of claims 1 to 12. A fall detection device according to any one of claims 1 to 13;
a light scanning unit that irradiates the fall detection area with light and detects the object according to the intensity of the reflected light;
A fall detection system equipped with A fall detection method for detecting a person who has fallen from a platform of a target station onto a track on which a train passes, comprising:
an object detection step of detecting an intrusion of an object into a fall detection area set on the track;
a signal receiving step of receiving an approach signal indicating an approach of a train to the target station as a result of the detection of a train at a station before the target station ;
a control step of starting detection of the object in the object detection step when the approach signal is received in the signal reception step;
A fall detection method comprising: A fall detection program that detects a person who has fallen from a platform of a target station onto a track on which a train passes,
an object detection step of detecting an intrusion of an object into a fall detection area set on the track;
a signal receiving step of receiving an approach signal indicating an approach of a train to the target station as a result of the detection of a train at a station before the target station ;
a control step of starting detection of the object in the object detection step when the approach signal is received in the signal reception step;
A fall detection program that causes a computer to execute a fall detection method comprising the steps of: