Alarm system

Abstract

This system enables the activation of an alarm if a vehicle mistakenly enters a designated work area along the road lanes. [Solution] The alarm system 1 includes a camera 10 with a zoom function, a control unit that controls the camera 10 to take an image of the near side of the work area 5 and to take an image of the far side of the work area 5 in an enlarged state, a determination unit that acquires images of the near side of the work area 5 and images of the far side of the work area 5 taken by the camera and determines whether or not the vehicle 7 has entered the work area 5 based on the acquired images, and an alarm device 30 that issues an alarm when the determination unit determines that the vehicle 7 has entered the work area 5 incorrectly.

Description

Technical Field

[0001] The present disclosure relates to an alarm system that issues an alarm when there is a vehicle that has mistakenly entered a work area demarcated on a part of the road on which the vehicle is traveling.

Background Art

[0002] When, for example, road repair or the like is carried out on a part of the road on which the vehicle is traveling, a work area is demarcated on a part of the road, and workers are performing various operations within the work area. While the work is being carried out in the work area, ordinary vehicles are traveling in other areas of the road. There is a risk that such an ordinary vehicle may mistakenly enter the work area, and an alarm system for warning of the entry of a vehicle into such a work area on the road is known (see, for example, Patent Documents 1 and 2).

[0003] The alarm systems of Patent Documents 1 and 2 include a three-dimensional ranging sensor that outputs the position information of the vehicle, and are configured to determine whether there is a high possibility that the vehicle will mistakenly enter the work area based on the time-series position information of the vehicle output from this three-dimensional ranging sensor. In Patent Documents 1 and 2, it is assumed that the work area is demarcated in an arc shape. Therefore, the three-dimensional ranging sensor irradiates measurement light upstream of the work area, identifies the front part of the vehicle, and then determines whether there is a high possibility that the vehicle will mistakenly enter the work area.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] Incidentally, depending on the nature of the work on the road, a long work area may be set up along the road lanes, and the length of such a work area can reach several hundred meters to several kilometers. When setting up such a long work area, multiple traffic cones are usually placed at predetermined intervals along the lanes to demarcate the work area.

[0006] However, since the spacing between adjacent traffic cones is such that vehicles can pass through, there is a risk that vehicles may enter the work area through the gaps between the cones.

[0007] In this regard, the alarm systems described in Patent Documents 1 and 2 only detect vehicles approaching from upstream of the work area using a 3D range sensor. Therefore, it is difficult to detect vehicles in the middle or downstream parts of a long work area of ​​several hundred meters to several kilometers.

[0008] This disclosure is made in view of the above, and its purpose is to enable the activation of an alarm when a vehicle mistakenly enters a work area set along a road lane. [Means for solving the problem]

[0009] To achieve the above objective, one aspect of this disclosure may be based on a warning system that warns of vehicle entry into a work area set along the extension of a road. The warning system includes a zoom camera installed at a predetermined position so as to be able to image the work area, a control unit that controls the camera and causes the camera to image the near side of the work area with respect to the predetermined position, and also causes the camera to image the far side of the work area in an enlarged state, a determination unit that acquires images of the near side of the work area and images of the far side of the work area taken by the camera, and determines whether or not a vehicle has entered the work area by mistake based on the acquired images, and a warning device that issues a warning when the determination unit determines that the vehicle has entered the work area by mistake.

[0010] With this configuration, for example, when the camera captures an image of the near side of the work area and then captures an image of the far side, the zoom function allows for an enlarged image of the far side. Therefore, if a vehicle is present in the far side of the work area, an image with a resolution sufficient to determine the presence or absence of the vehicle can be obtained.

[0011] Conversely, when the camera captures an image of a distant area at a magnified view, it can then zoom in to capture an image of a nearby area at a reduced view, thus expanding the field of view. This allows for obtaining an image with sufficient resolution to determine the presence or absence of a vehicle over a wide area of ​​the work zone at close range.

[0012] In this way, using a single camera, it is possible to acquire images with a resolution sufficient to determine the presence or absence of a vehicle, from the near side close to the camera's installation position to the far side far from the camera's installation position. Based on the acquired images, it is possible to determine whether or not a vehicle has mistakenly entered the work area, making it possible to detect vehicle misapplications not only in the upstream part of the work area, but also in the middle and downstream parts.

[0013] The camera may include a drive unit that rotates an imaging unit having a lens and an image sensor around an axis extending in the vertical direction. In this case, the control unit can control the drive unit to rotate the imaging unit, thereby switching the optical axis of the lens from one state facing the near side of the work area to the other state facing the far side. This allows for automatic imaging with the optical axis of the lens facing the near side of the work area and imaging with the optical axis of the lens facing the far side.

[0014] The control unit can also control the drive unit to rotate the imaging unit, thereby switching the optical axis of the lens from being pointed towards the upstream or downstream side of the road to being pointed towards the other side. This makes it possible to detect vehicles over a wide area, from the upstream to the downstream side of the work area, with a single camera.

[0015] The control unit can also have the camera capture an image of either the near side of the work area or the far side of the work area, and then, after a predetermined time has elapsed, capture the other side. In other words, since the frequency of vehicles mistakenly entering the work area is generally low, it is often not a problem in actual operation to capture images of the far and near sides of the work area at time intervals, rather than capturing images of the work area continuously. In this configuration, by capturing images of the far and near sides of the work area at time intervals, the processing load on the alarm system can be reduced while appropriately issuing alarms for mistaken entry.

[0016] The alarm system may further include a storage unit that stores the zoom magnification for near imaging and the rotation angle of the imaging unit when imaging the near side of the work area, and the zoom magnification for far imaging and the rotation angle of the imaging unit when imaging the far side of the work area. In this case, the control unit can perform either near imaging control, which controls the camera based on the zoom magnification for near imaging and the rotation angle of the imaging unit stored in the storage unit, or far imaging control, which controls the camera based on the zoom magnification for far imaging and the rotation angle of the imaging unit stored in the storage unit, and then perform the other.

[0017] The alarm system may further include a receiving unit that receives the settings for the zoom magnification for near imaging and the rotation angle of the imaging unit, and the settings for the zoom magnification for far imaging and the rotation angle of the imaging unit. In this case, the storage unit can store the zoom magnification for near imaging and the rotation angle of the imaging unit, and the zoom magnification for far imaging and the rotation angle of the imaging unit, which have been received by the receiving unit, so that settings can be made according to the situation on site.

[0018] The warning system may further include a communication unit that transmits an image determined by the determination unit that the vehicle has erroneously entered the work area to a terminal device having a display unit. That is, when it is determined that the vehicle has erroneously entered the work area, not only a warning is issued, but also an image is transmitted to a terminal device possessed by a work administrator or the like, so that the specific situation can be grasped.

Advantages of the Invention

[0019] As described above, the work area set along the vehicle lane of the road is imaged from the near side to the far side by a camera with a zoom function, and it is determined whether or not a vehicle has erroneously entered the work area based on the captured image. Therefore, even in the case of a work area that is, for example, several hundred meters to several kilometers long, a warning can be issued when a vehicle erroneously enters the work area.

Brief Description of the Drawings

[0020] [Figure 1] FIG. 1 is a plan view of a road for explaining the usage state of the warning system according to Embodiment 1 of the present invention. [Figure 2] FIG. 2 is an external view of the camera. [Figure 3] FIG. 3 is a block diagram of the warning system. [Figure 4] FIG. 4 is a plan view of a road for explaining the positional relationship between the near side and the far side of the work area. [Figure 5] FIG. 5 is a block diagram of the warning system according to Embodiment 2 of the present invention. [Figure 6] FIG. 6 is a plan view of a road for explaining the usage state of the warning system according to Embodiment 2 of the present invention. [Figure 7] FIG. 7 is a block diagram of the warning system according to Embodiment 3 of the present invention.

Modes for Carrying Out the Invention

[0021] Embodiments of the present invention will be described in detail below with reference to the drawings. The following description of preferred embodiments is essentially illustrative and is not intended to limit the present invention, its applications, or its uses.

[0022] (Embodiment 1) Figure 1 is a plan view of a road 3 illustrating the usage state of a warning system 1 according to Embodiment 1 of the present invention. This warning system 1 is installed, for example, on the road 3 or on a side road, and is intended to warn of the entry of general vehicles 7 into a work area 5 that is pre-demarcated on the road 3. The road 3 has three lanes 9a, 9b, and 9c that all travel in the same direction, and a work area 5 for road construction work, etc., is set up along the extension of the road 3, for example, in the leftmost lane 9a in the direction of travel. In Figure 1, the work area 5 is shown by a dotted diagonal line. In the work area 5, road repair work, equipment installation work, equipment maintenance work, wiring and piping work, etc., are carried out. The number of lanes may be two or four or more. The work area 5 is demarcated over any length at any location where work is needed. In this embodiment, a case is described in which the work area 5 is provided continuously over a long range of several hundred meters or more, for example, 1 km or several km. General vehicles 7 also include motorcycles.

[0023] Vehicles traveling in lanes 9a, 9b, and 9c travel in the same direction. A lane boundary line L1 is drawn between lanes 9a, 9b, and 9c, extending in the direction of the extension of road 3 (left-right direction in Figure 1). The right side of Figure 1 is the upstream side of road 3, and the left side of Figure 1 is the downstream side of road 3. Therefore, general vehicles 7 travel from right to left in Figure 1.

[0024] Multiple traffic cones (partition members) C1 are placed on the road 3 to demarcate the work area 5. The traffic cones C1 are lined up along the lane boundary line L1 between lane 9a and lane 9b. In the example shown in Figure 1, the traffic cones C1 are placed on the lane boundary line L1, but they are not limited to this and may be placed at a position offset from the lane boundary line L1 in the width direction of the road 3. In addition, the work area 5 may be demarcated by members other than traffic cones C1.

[0025] The spacing between adjacent traffic cones C1 in the direction of the extension of road 3 can be set to, for example, about 20m, but is not limited to this. Generally, the spacing between traffic cones C1 is such that general vehicles 7 can enter. For this reason, there is a possibility that a general vehicle 7 traveling in lane 9b adjacent to the work area 5 may, for some reason, enter the work area 5 from between adjacent traffic cones C1. The warning system 1 detects when a general vehicle 7 enters the work area 5 from the part of lane 9b adjacent to the work area 5 that is located to the side of the work area 5, and issues a warning, for example, if necessary.

[0026] Alarm system 1 comprises a camera 10, a control unit 20, and a speaker 30. The alarm system 1 is powered by a power supply 40. The power supply 40 may be, for example, a battery, a commercial power supply, or a generator. The power supply 40 may also constitute a part of the alarm system 1. The camera 10, control unit 20, and speaker 30 may be integrated, or partially separate. The control unit 20 and speaker 30 can also be installed separately from the camera 10.

[0027] Camera 10 is installed in a predetermined position (installation position) so as to be able to capture images of at least the work area 5. In this embodiment, the installation position of camera 10 is to the side of the work area 5 (on the side opposite to lane 9b) and in the middle of the extension direction of road 3 in the work area 5. If the work area 5 is, for example, about 2 km, the installation position of camera 10 can be set so that the distance from the installation position of camera 10 to the upstream part (upstream end) of the work area 5 and the distance from the installation position of camera 10 to the downstream part (downstream end) of the work area 5 are both about 1 km. The installation position of camera 10 may be closer to the upstream end of the work area 5 or closer to the downstream end of the work area 5. In addition, multiple cameras 10 may be installed as needed, and for example, if the extension direction of the work area 5 is a long distance of about 3 km or 4 km, two or three or more cameras 10 can be installed and operated.

[0028] As shown in Figure 2, the camera 10 is mounted, for example, on a mounting base A. The mounting base A can be used as needed, and the camera 10 may be mounted on a component such as a tripod. The camera 10 comprises a fixing part 11 fixed to the mounting base A and a main body part 12. The main body part 12 has an imaging unit 13 and a housing 12A that houses the imaging unit 13. As also shown in Figure 3, the imaging unit 13 consists of an electric zoom lens 13a and an image sensor 13b. The imaging unit 13 is formed by integrating the electric zoom lens 13a and the image sensor 13b. This makes the camera 10 a camera with a zoom function.

[0029] The motorized zoom lens 13a is an optical zoom lens, but it may also be used in conjunction with digital zoom, which enlarges an image by, for example, stretching and cropping a portion of the image using image processing. The zoom magnification of the motorized zoom lens 13a is not particularly limited, but is set to a high magnification of, for example, 0.5x to 10x or 20x. The image sensor 13b is equipped with two-dimensionally arranged light-receiving elements. The relative positions of the motorized zoom lens 13a and the image sensor 13b are fixed so that the light emitted from the motorized zoom lens 13a is received by the image sensor 13b.

[0030] The camera 10 is equipped with a pan-direction drive motor (drive unit) 14. The pan-direction drive motor 14 has a motor body 14a fixed to a fixed part 11 and an output shaft 14b extending in the vertical direction. The main body 12 is fixed to the upper part of the output shaft 14b. Therefore, by operating the pan-direction drive motor 14, it becomes possible to rotate the imaging unit 13, which includes the motorized zoom lens 13a and the image sensor 13b, around the axis (output shaft 14b) that extends in the vertical direction. Rotating the imaging unit 13 around the axis that extends in the vertical direction can also be called "panning". The axis of rotation of the imaging unit 13 may be vertical or inclined with respect to the vertical. The pan-direction drive motor 14 is just one example of a drive unit, and any structure is acceptable as long as it can rotate the imaging unit 13 around the axis that extends in the vertical direction.

[0031] The camera 10 is equipped with a tilt drive motor 15. The tilt drive motor 15 has a motor body 15a fixed to the housing 12A and an output shaft 15b extending horizontally. The imaging unit 13 is fixed to the tip of the output shaft 15b. Therefore, by operating the tilt drive motor 15, it is possible to rotate the imaging unit 13, which includes the motorized zoom lens 13a and the image sensor 13b, around the axis extending horizontally (output shaft 15b). Rotating the imaging unit 13 around the axis extending horizontally can also be called "tilting". The tilt drive motor 15 may be provided as needed. The imaging unit 13 may also be rotated around an axis inclined with respect to the horizontal.

[0032] Thus, the camera 10 has a zoom function as well as pan and tilt functions. By changing the zoom magnification of the motorized zoom lens 13a, it is possible to widen or narrow the field of view that can be captured by the image sensor 13b, and to enlarge or reduce the image formed on the surface of the image sensor 13b. Furthermore, by operating the pan-direction drive motor 14, the direction of the optical axis of the motorized zoom lens 13a can be arbitrarily changed, for example, to point it towards the upstream part, the downstream part, or the intermediate part in the extension direction of the road 3 in the work area 5. It is also possible to continuously or intermittently change the optical axis of the motorized zoom lens 13a from the upstream part to the downstream part in the extension direction of the road 3 in the work area 5, or conversely, continuously or intermittently change it from the downstream part to the upstream part in the extension direction of the road 3 in the work area 5. The pan range can be set to, for example, 180° or more. Furthermore, by operating the tilt-direction drive motor 15, the direction of the optical axis of the motorized zoom lens 13a can be changed in the vertical direction.

[0033] The control unit 20 comprises a control unit 21, a determination unit 22, a reception unit 23, a storage unit 24, a communication unit 25, and an image recording unit 26. The control unit 21, the determination unit 22, and the reception unit 23 are composed of a microcomputer (including a central processing unit, ROM, RAM, etc.) in the control unit 20 and software executed by the microcomputer. The control unit 21, the determination unit 22, and the reception unit 23 may be composed of a combination of hardware such as a central processing unit, ROM, RAM, etc., and software such as programs and applications.

[0034] The control unit 21 is the part that controls, for example, the camera 10 and the speaker 30. Specifically, the motorized zoom lens 13a, pan-direction drive motor 14, and tilt-direction drive motor 15 of the camera 10 are individually controlled by the control unit 21 and operate at the required timing.

[0035] As schematically shown in Figure 4, by controlling the motorized zoom lens 13a, it becomes possible to change the magnification so that the near side R1A and R1B of the work area 5 are included in the field of view, relative to the camera's installation position P1, and also so that the far side R2A and R2B of the work area 5 are included in the field of view, relative to the camera's installation position P1.

[0036] The near-field R1A and R1B are the sides closer to the installation position P1 in the work area 5, and the powered zoom lens 13a is set to a lower magnification compared to when imaging the far-field R2A and R2B. The far-field R2A and R2B are the sides further from the installation position P1 in the work area 5, and the powered zoom lens 13a is set to a higher magnification compared to when imaging the near-field R1A and R1B.

[0037] For example, if the optical axis of the power zoom lens 13a is directed towards the upstream portion of the road 3 in the extension direction in the work area 5 (right side in Figure 4), the portion closer to the camera 10 installation position P1 than the midpoint P3 between the camera 10 installation position P1 and the upstream end P2 of the work area 5 becomes the near side R1A, while the portion closer to the upstream end P2 than the midpoint P3 between the camera 10 installation position P1 and the upstream end P2 of the work area 5 becomes the far side R2A. The range of the imaging field of view when imaging the far side R2A is indicated by the symbol D1. The range of the imaging field of view when imaging the near side R1A is indicated by the symbol D2.

[0038] Furthermore, when the optical axis of the power zoom lens 13a is directed towards the downstream portion of the road 3 in the extension direction in the work area 5 (left side in Figure 4), the portion closer to the camera 10 installation position P1 than the midpoint P5 between the camera 10 installation position P1 and the downstream end P4 of the work area 5 becomes the near side R1B, while the portion closer to the downstream end P4 than the midpoint P5 between the camera 10 installation position P1 and the downstream end P4 of the work area 5 becomes the far side R2B. The range of the imaging field of view when imaging the far side R2B is indicated by the symbol D4. The range of the imaging field of view when imaging the near side R1B is indicated by the symbol D5.

[0039] When imaging the near-field R1A and R1B, and when imaging the far-field R2A and R2B, the images are taken at a magnification that allows the vehicle to be accurately identified by the determination unit 22, which will be described later. The magnification for imaging the near-field R1A and R1B, and the magnification for imaging the far-field R2A and R2B, can be set in advance during installation (adjustment) before operation.

[0040] Although not mandatory, the intermediate region between the near-field R1A and the far-field R2A can also be imaged by camera 10. When imaged in the intermediate region, the magnification of the power zoom lens 13a should be lower than when imaged in the far-field R2A and R2B, and higher than when imaged in the near-field R1A and R1B. The range of the imaging field when imaging the upstream intermediate region is indicated by symbol D3, and the range of the imaging field when imaging the downstream intermediate region is indicated by symbol D6. The intermediate region may be divided into multiple areas, and intermediate areas close to the far-field R2A and R2B and intermediate areas close to the near-field R1A and R1B may be set. The range of the imaging field when imaging the area directly in front of camera 10 is indicated by symbol D7. When imaging imaging field D7, the magnification of the power zoom lens 13a should be the lowest compared to the other imaging fields D1 to D6.

[0041] When switching the imaging field of view of camera 10, in addition to controlling the motorized zoom lens 13a, the pan-direction drive motor 14 is also controlled. When the imaging field of view of camera 10 is set to imaging field of view D1, the pan-direction drive motor 14 is controlled to rotate the imaging unit 13 so that the optical axis of the motorized zoom lens 13a is positioned in the center of the width direction of imaging field of view D1. In the same manner, the imaging field of view of camera 10 can be switched to imaging fields of view D2, D3, D4, D5, D6, and D7.

[0042] In other words, the control unit 21 controls the pan-direction drive motor 14 to rotate the imaging unit 13, thereby switching the optical axis of the motorized zoom lens 13a from one state, where it is pointed towards the near side R1A and R1B of the work area 5, to the far side R2A and R2B of the work area 5, and also from one state, where the optical axis of the motorized zoom lens 13a is pointed towards the upstream side and the downstream side of the road 3, to the other state. Furthermore, the control unit 21 controls the camera 10 to image the near side R1A and R1B of the work area 5 with the camera 10, using the installation position P1 as a reference, and also to image the far side R2A and R2B of the work area 5 with the camera 10 in an enlarged state. When switching the imaging field of view of the camera 10, the tilt-direction drive motor 15 may be controlled as needed to adjust the optical axis in the vertical direction.

[0043] As shown in Figures 1 and 3, the camera 10 and the control unit 20 are connected by a communication line 20a. An imaging control signal is transmitted from the control unit 21 of the control unit 20 to the camera 10 via the communication line 20a. Images captured by the camera 10 are sequentially transmitted to the control unit 20 via the communication line 20a. The control unit 21 that controls the camera 10 may be built into the camera 10.

[0044] The control unit 21 uses the camera 10 to image one of the near side R1A, R1B and the far side R2A, R2B of the work area 5, and then, after a predetermined time has elapsed, it images the other. This predetermined time can be set to, for example, a few seconds to several tens of seconds. For example, it is possible to image the far side R2A upstream of the work area 5, then after a predetermined time has elapsed, image the near side R1A upstream, then after a predetermined time has elapsed, image the far side R2B downstream, and then after a predetermined time has elapsed, image the near side R1B downstream. The near side R1A, R1B and the far side R2A, R2B may be imaged intermittently in this manner, but it is not limited to this, and the near side R1A, R1B and the far side R2A, R2B may be imaged continuously.

[0045] The memory unit 24 stores the zoom magnification and rotation angle of the imaging unit 13 for near imaging when imaging the near side R1A and R1B of the work area 5, and the zoom magnification and rotation angle of the imaging unit 13 for far imaging when imaging the far side R2A and R2B of the work area 5. When imaging the intermediate area, the zoom magnification and rotation angle of the imaging unit 13 for imaging the intermediate area are also stored in the memory unit 24. Each zoom magnification and rotation angle of the imaging unit 13 can be set as described above.

[0046] The control unit 21 reads out the zoom magnification and rotation angle of the imaging unit 13 stored in the memory unit 24. Then, the control unit 21 performs either near imaging control, which controls the camera 10 based on the zoom magnification for near imaging and the rotation angle of the imaging unit 13 for near imaging, or far imaging control, which controls the camera 10 based on the zoom magnification for far imaging and the rotation angle of the imaging unit 13 for far imaging stored in the memory unit 24, and then performs the other. When imaging an intermediate region, the control unit 21 performs intermediate region imaging control, which controls the camera 10 based on the zoom magnification for intermediate region imaging and the rotation angle of the imaging unit 13 for intermediate region imaging, after the far imaging control or near imaging control. The execution order of intermediate region imaging control, far imaging control, and near imaging control is not particularly limited.

[0047] The reception unit 23 is the part that receives the settings for the zoom magnification and rotation angle of the imaging unit 13 for near imaging, and the settings for the zoom magnification and rotation angle of the imaging unit 13 for far imaging. The storage unit 24 stores the zoom magnification and rotation angle of the imaging unit 13 for near imaging and the zoom magnification and rotation angle of the imaging unit 13 for far imaging that have been received by the reception unit 23. When imaging an intermediate region, the reception unit 23 can also receive the zoom magnification and rotation angle of the imaging unit 13 for intermediate region imaging, and the received zoom magnification and rotation angle of the imaging unit 13 for intermediate region imaging are stored in the storage unit 24.

[0048] The zoom magnification and the rotation angle of the imaging unit 13 can be set using the setting device 50 shown in Figure 3. The setting device 50 consists of, for example, a tablet terminal, a smartphone, or a notebook personal computer. The setting device 50 has a display unit 51 consisting of a liquid crystal display panel or an organic EL panel, an input unit 52, and a communication unit 53. The input unit 52 consists of, for example, a touch-operable touch panel, a keyboard, or a mouse, and the user of the setting device 50 can operate it to input and select various information. The communication unit 53 can be, for example, an LTE communication module, but it may also be a wired communication module. The control unit 20 is provided with a communication unit 25 configured in the same way as the communication unit 53 of the setting device 50, so that this communication unit 25 and the communication unit 53 of the setting device 50 can communicate with each other.

[0049] The user of the setting device 50 operates the input unit 52 while viewing the display unit 51 to input the zoom magnification and the rotation angle of the imaging unit 13. The zoom magnification and the rotation angle of the imaging unit 13 can be input separately for near imaging, far imaging, and intermediate region imaging. The information input at the input unit 52 is transmitted from the communication unit 53 of the setting device 50 to the communication unit 25 of the control unit 20. Based on the information received at the communication unit 25 of the control unit 20, the control unit 20 acquires the zoom magnification and the rotation angle of the imaging unit 13. The control unit 20 stores the acquired zoom magnification and the rotation angle of the imaging unit 13 in the storage unit 24. The setting device 50 may be incorporated into the control unit 20. The control unit 20 may also be provided with an input unit for inputting the zoom magnification and the rotation angle of the imaging unit 13.

[0050] The determination unit 22 acquires images of the near side R1A and R1B of the work area 5 and images of the far side R2A and R2B of the work area 5 from the camera 10, and determines whether or not a general vehicle 7 has mistakenly entered the work area 5 based on the acquired images. The determination unit 22 determines whether or not a general vehicle 7 is present in the acquired images based on image processing. For example, it calculates the difference between an image taken when no general vehicle 7 is present and a newly taken image, and if that difference corresponds to a general vehicle 7, the determination unit 22 determines that a general vehicle 7 has mistakenly entered the work area 5. On the other hand, if the difference between an image taken when no general vehicle 7 is present and a newly taken image is extremely small, and there is no equivalent to a general vehicle 7 in the newly taken image, the determination unit 22 determines that a general vehicle 7 has not entered the work area 5. Conventional algorithms can be used when determining whether or not a general vehicle 7 has mistakenly entered the work area 5. Furthermore, a machine learning model may be used to determine whether or not a general vehicle 7 has mistakenly entered the work area 5.

[0051] Speaker 30 is an example of an alarm device that issues an alarm when the determination unit 22 determines that a general vehicle 7 has mistakenly entered the work area 5. Speaker 30 is connected to the control unit 20. When an operation signal is output from the control unit 20, a warning sound wave (alarm sound) is emitted from speaker 30. Speaker 30 may be, for example, a speaker that emits sound waves in the audible range, or it may be an ultrasonic speaker. In the case of an ultrasonic speaker, when the sound wave emitted from the ultrasonic speaker hits the general vehicle 7, it can vibrate the components that make up the general vehicle 7, allowing the occupants to hear a warning sound.

[0052] Instead of the speaker 30, or in addition to the speaker 30, a lighting device or the like may be provided as an alarm device. If the determination unit 22 determines that a general vehicle 7 has mistakenly entered the work area 5, the lighting device will be illuminated to warn the occupants of the general vehicle 7.

[0053] Alarm sounds and lights can also be emitted towards workers performing various tasks within the work area 5. For example, by installing speakers 30 and lighting devices near workers, if the determination unit 22 determines that a general vehicle 7 has mistakenly entered the work area 5, the workers can be notified. This allows workers to evacuate from the work area 5. Multiple alarm devices may be provided. As an example of an alarm device, an individual alarm unit can be attached to a worker's helmet. The individual alarm unit is configured to receive operation signals from the control unit 20 via wireless communication. Upon receiving an operation signal from the control unit 20, it operates as if to strike the helmet, generating sound and vibration to notify the worker.

[0054] The communication unit 25 of the control unit 20 transmits an image, determined by the determination unit 22 to indicate that a general vehicle 7 has mistakenly entered the work area 5, to the terminal device 60. The terminal device 60 is, for example, a terminal device held by a work manager or worker, and has a display unit 61 consisting of a liquid crystal display panel or an organic EL panel, and a communication unit 62 consisting of a communication module that can communicate with the communication unit 25 of the control unit 20. The image received by the communication unit 62 of the terminal device 60 is displayed on the display unit 61. This allows managers and workers to check what kind of general vehicle 7 has mistakenly entered and where in the work area 5, by looking at the image captured by the camera 10.

[0055] The image recording unit 26 is the part that records images transmitted to the control unit 20 as image data, and is composed of, for example, a network video recorder or various recording media. By recording images in the image recording unit 26, past images can be accumulated. Images recorded in the image recording unit 26 can be acquired by the setting device 50 or terminal device 60. The acquired images can be displayed on the display units 51 and 61.

[0056] (Effects of the embodiment) As described above, according to this embodiment, the camera 10 can capture images of the near side R1A, R1B and the far side R2A, R2B of the work area 5 in a time series. After capturing images of the near side R1A, R1B of the work area 5, when capturing images of the far side R2A, R2B of the work area 5, the magnification of the motorized zoom lens 13a is increased, making it possible to capture images of the far side R2A, R2B in a magnified state. Therefore, if a general vehicle 7 is present in the far side R2A, R2B of the work area 5, an image with a resolution that allows the determination unit 22 to accurately determine the presence or absence of the general vehicle 7 can be obtained.

[0057] Conversely, after the camera 10 has captured images of the far side R2A and R2B of the work area 5 in an enlarged state, when it captures images of the near side R1A and R1B of the work area 5, it is possible to reduce the magnification of the motorized zoom lens 13a to capture images in a reduced state, that is, in a state with an enlarged field of view. As a result, images with a resolution that allows for the determination of the presence or absence of general vehicles 7 over a wide area of ​​the work area 5 can be obtained for the near side R1A and R1B.

[0058] In this way, using a single camera 10, images with a resolution sufficient to determine the presence or absence of a general vehicle 7 can be acquired from the near-field R1A and R1B, which are close to the camera 10's installation position, to the far-field R2A and R2B, which are far from the camera 10's installation position. The determination unit 22 can then determine whether or not a general vehicle 7 has mistakenly entered the work area 5 based on the high-resolution images acquired by the camera 10. Therefore, it is possible to detect when a general vehicle 7 has mistakenly entered the work area 5 not only in the upstream area but also in the middle and downstream areas. If it is determined that a general vehicle 7 has mistakenly entered the work area 5, an alarm can be immediately issued to notify the system.

[0059] The embodiments described above are merely illustrative in all respects and should not be interpreted restrictively. Furthermore, any modifications or changes within the equivalent scope of the claims are all within the scope of the present invention. For example, the camera 10 may capture video. In this case as well, by controlling the camera 10 based on a preset zoom magnification and the rotation angle of the imaging unit 13, it is possible to detect when a general vehicle 7 mistakenly enters the work area 5 not only upstream but also in the middle and downstream sections. Images captured by the camera 10 can also be transmitted in real time to the setting device 50 and terminal device 60.

[0060] (Embodiment 2) Figures 5 and 6 illustrate an alarm system 1 according to Embodiment 2 of the present invention. Embodiment 2 differs from Embodiment 1 in that it is equipped with a beacon detector (detector) 38, but other parts are the same as those in Embodiment 1. Therefore, the same reference numerals are used for the same parts as in Embodiment 1, and their descriptions are omitted below. The different parts will be described in detail below.

[0061] As shown in Figure 6, authorized vehicles 70 that are permitted to enter the work area 5 are equipped with beacons (transmitters) 70a that emit radio waves of a predetermined frequency. The beacon detector 38 is a device that receives radio waves emitted from the beacon 70a attached to the authorized vehicle 70 and is connected to the control unit 20.

[0062] The determination unit 22 determines whether a vehicle is an authorized vehicle 70 permitted to enter the work area 5, based on the radio wave reception result from the beacon detector 38. Specifically, if the beacon detector 38 receives radio waves emitted from a beacon 70a attached to the authorized vehicle 70, the determination unit 22 determines that the vehicle located near the control unit 20 is an authorized vehicle 70 permitted to enter the work area 5. On the other hand, if the determination unit 22 does not receive radio waves emitted from the beacon 70a, the determination unit 22 determines that the vehicle located near the control unit 20 is a general vehicle 7 not permitted to enter the work area 5. If it is determined to be an authorized vehicle 70, the determination unit 22 does not determine that it is an unauthorized entry even if the authorized vehicle 70 enters the work area 5.

[0063] (Embodiment 3) Figure 7 illustrates an alarm system 1 according to Embodiment 3 of the present invention. The alarm system 1 according to Embodiment 3 is equipped with an administrator terminal 80 instead of a speaker 30. For example, if an alarm is issued by the speaker 30, the driver of the vehicle 7 may be startled, so the administrator terminal 80 is used as the alarm device instead of the speaker 30. The administrator terminal 80 is a device held by an administrator located several kilometers or more away from the work area 5, and specifically includes a smartphone, tablet terminal, or notebook personal computer. These devices are equipped with a communication module configured to enable communication compliant with communication standards such as LTE.

[0064] The communication unit 25 (shown in Figure 3) of the control unit 20 is composed of a communication module configured to enable communication compliant with communication standards such as LTE. When the detection unit 22 determines that a general vehicle 7 has mistakenly entered the work area 5, the communication unit 25 transmits a notification of the mistaken entry and live images captured by the camera 10 to the administrator terminal 80 via the cloud. The administrator terminal 80 has a dedicated application installed, and an alert indicating the mistaken entry is displayed on the display screen as an icon or message, along with the live image. This allows the administrator to understand the situation of the mistaken entry, even while away from the work area 5. In the embodiment 3, a speaker 30 and a lighting device may be used in conjunction with the administrator terminal 80. [Industrial applicability]

[0065] As explained above, the alarm system relating to this disclosure can be used, for example, when a work area is demarcated on a part of a road on which a vehicle is traveling and various tasks are performed there. [Explanation of Symbols]

[0066] 1. Alarm System 3 road 5 Working area 10 Cameras 14. Pan direction drive motor (drive unit) 21 Control Unit 22 Judgment section 23 Reception Department 24 Memory section 30 speakers (alarm device)

Claims

1. A warning system that alerts vehicles to entering a work area set along the direction of the road's extension, A camera with a zoom function, which is installed in a predetermined position so as to be able to image at least the work area, A control unit controls the camera and causes it to capture images of the near side of the work area with respect to the predetermined position, and to capture images of the far side of the work area with the camera in an enlarged state, The camera acquires images of the near side of the work area and images of the far side of the work area, and a determination unit determines whether or not a vehicle has entered the work area by means of the acquired images. An alarm system comprising: an alarm device that issues an alarm when the determination unit determines that the vehicle has entered the work area incorrectly.

2. In the alarm system according to claim 1, The camera includes a drive unit that rotates the imaging unit, which includes a lens and an image sensor, around an axis extending in the vertical direction. The control unit controls the drive unit to rotate the imaging unit, thereby switching the optical axis of the lens from one state, where it is pointed towards the near side of the work area, to the other state, and from the other state, where it is pointed towards the far side of the work area.

3. In the alarm system according to claim 2, The control unit controls the drive unit to rotate the imaging unit, thereby switching the optical axis of the lens from being directed towards the upstream or downstream side of the road to being directed towards the other side, as an alarm system.

4. In the alarm system according to claim 1, The control unit is an alarm system that causes the camera to capture an image of either the near side of the work area or the far side of the work area, and then, after a predetermined time has elapsed, capture an image of the other side.

5. In the alarm system according to claim 2, The system further includes a storage unit that stores the zoom magnification for near imaging and the rotation angle of the imaging unit when imaging the near side of the work area, and the zoom magnification for far imaging and the rotation angle of the imaging unit when imaging the far side of the work area. An alarm system in which the control unit first performs one of the following: near imaging control, which controls the camera based on the zoom magnification for near imaging and the rotation angle of the imaging unit stored in the memory unit; and far imaging control, which controls the camera based on the zoom magnification for far imaging and the rotation angle of the imaging unit stored in the memory unit; and then performs the other.

6. In the alarm system according to claim 5, The system further includes a receiving unit that receives the settings for the zoom magnification for near imaging and the rotation angle of the imaging unit, and the settings for the zoom magnification for far imaging and the rotation angle of the imaging unit. The alarm system includes a memory unit that stores the zoom magnification for near imaging and the rotation angle of the imaging unit, as well as the zoom magnification for far imaging and the rotation angle of the imaging unit, which are received by the reception unit.

7. In the alarm system according to claim 1, The alarm system further includes a communication unit that transmits an image, determined by the determination unit to indicate that the vehicle has entered the work area incorrectly, to a terminal device having a display unit.

Images