Monitoring device

Abstract

A monitoring device characterized by comprising: a sensor module that emits light or radio waves to a preset monitoring area and detects the light or radio waves reflected and returned from the monitoring area to detect an object that has entered the monitoring area; a camera module having a dark-field light source for enabling imaging in a dark field of the monitoring area and an imaging means for imaging the object irradiated with illumination light from the dark-field light source; and an imaging scanning means capable of scanning the illumination light along the monitoring area.

Description

monitoring device

[0001] The present invention relates to a surveillance device used for crime prevention.

[0002] As disclosed in Patent Document 1, a conventional monitoring device includes an infrared sensor that detects an intruder in a monitoring area and an image sensor that captures an image of the detected intruder.

[0003] This image sensor uses an infrared light source that emits infrared light into the monitored area so that it can capture an image of the monitored area even at night.

[0004] However, in order for such a surveillance device to be able to emit infrared light for imaging purposes regardless of the position of the intruder in the surveillance area, it is necessary to install a large number of infrared light sources in order to emit infrared light in various directions.

[0005] As a result, the cost and size of the device increases, and it may even be practically difficult to install a sufficient number of infrared light sources, particularly when the monitoring area is long distance.

[0006] Japanese Patent Application Laid-Open No. 2000-341675

[0007] Therefore, the present invention has been made to solve the above problems, and its main objective is to enable reliable imaging of intruders into the monitored area regardless of their location, without increasing the number of dark field light sources required to enable dark field imaging. Means for solving the invention

[0008] In other words, the monitoring device of the present invention is characterized by comprising a sensor module that detects an object that has entered a predetermined monitoring area by emitting light or radio waves into the monitoring area and detecting the light or radio waves that have been reflected back from the monitoring area, a camera module that has a dark field light source to enable imaging of the monitoring area in the dark field and an imaging means that images the object illuminated with illumination light from the dark field light source, and an imaging scanning means that can scan the illumination light along the monitoring area.

[0009] A surveillance device configured in this manner is equipped with an imaging scanning means that can scan the illumination light emitted from the dark field light source along the surveillance area, so there is no need to position the dark field source facing various directions in the surveillance area, and it is possible to reliably image intruders into the surveillance area regardless of their position without increasing the number of light sources installed.

[0010] It is preferable that the illumination light from the dark field light source is scanned by an imaging scanning means so that the illumination light is emitted only to a detection area that is a part of the monitoring area and where an object is detected by the sensor module. With this configuration, power consumption due to irradiation of the illumination light can be reduced.

[0011] Specific examples of the sensor module include a LiDAR sensor and a RaDAR sensor.

[0012] It is preferable that the sensor module has a sensor scanning means for scanning a laser beam along the monitoring area, and that at least some of the components constituting the sensor scanning means also serve as the imaging scanning means. With such a configuration, the number of parts can be reduced, leading to a smaller size and lower costs of the device.

[0013] An example of an embodiment for reducing the number of parts is one in which the sensor scanning means has a laser light mirror that reflects the laser light, a rotation shaft connected to the laser light mirror, and a motor connected to the rotation shaft, and the imaging scanning means has an illumination light mirror that reflects the illumination light, and the rotation shaft is connected to the illumination light mirror. In this case, the rotation shaft and the motor are combined, so the number of parts can be reduced accordingly.

[0014] Another embodiment for reducing the number of parts is one in which the sensor scanning means has a mirror that reflects the laser light, a rotating shaft connected to the mirror, and a motor connected to the rotating shaft, and the mirror is a double-sided mirror that also serves as the imaging scanning means, and reflects the illumination light on the back side of the reflective surface that reflects the laser light. In this case, the rotating shaft, motor, and mirror are shared, so the number of parts can be reduced accordingly.

[0015] It is preferable that the camera module has a plurality of the dark field light sources, and the imaging scanning means is capable of scanning the illumination light emitted from each of the plurality of dark field light sources along the monitoring area. In this case, since there are a plurality of dark field light sources, the amount of illumination light irradiated onto an object intruding into the monitoring area can be increased, and the intruder can be imaged more clearly.

[0016] It is preferable that the illumination light emitted from the dark field light source is pulsed light, which can reduce power consumption due to irradiation of the illumination light.

[0017] It is preferable that the monitoring system further includes a visible light source that emits visible light into the monitoring area, and the visible light from the visible light source is irradiated onto the object detected by the sensor module. In this case, by irradiating visible light to an intruder into the monitoring area, the intruder can be intimidated.

[0018] According to the present invention configured in this manner, it is possible to reliably capture images of intruders into the monitored area regardless of their location, without increasing the number of dark field light sources required to enable dark field imaging.

[0019] 1 is a schematic diagram showing the configuration of a monitoring device according to one embodiment of the present invention; a schematic diagram showing a monitoring area and an imaging area of ​​the same embodiment; a functional block diagram showing the functions of a control module of the same embodiment; a schematic diagram showing the configuration of a sensor scanning means and an imaging scanning means of the same embodiment; a schematic diagram showing the configuration of a sensor scanning means and an imaging scanning means of another embodiment; a schematic diagram showing the configuration of a dark-field light source of another embodiment; a schematic diagram showing the configuration of a sensor scanning means and an imaging scanning means of another embodiment; a schematic diagram showing the configuration of a sensor scanning means and an imaging scanning means of another embodiment;

[0020] A monitoring device 100 according to an embodiment of the present invention will be described with reference to the drawings. However, the present invention is not limited to the following description.

[0021] [Overall configuration of monitoring device 100] The monitoring device 100 of this embodiment is used to guard various facilities, such as business facilities such as offices, commercial facilities, airports, and train stations, and detects intruders into a predetermined monitoring area X indoors or outdoors and captures an image of the intruder.

[0022] Specifically, as shown in FIG. 1, the monitoring device 100 includes a sensor module 10, a camera module 20, and a control module 30.

[0023] As shown in Figures 1 and 2, the sensor module 10 detects objects present in a predetermined monitoring area X, and more specifically, detects objects that have entered the monitoring area X.

[0024] The sensor module 10 emits light or radio waves into a monitored area X and detects the light or radio waves reflected by an object that enters the monitored area X.

[0025] The sensor module 10 of this embodiment is a LiDAR sensor, and specifically, as shown in FIG. 1, includes a light source 11, a sensor scanning means 12 that scans the light emitted from the light source 11, and a photodetector 13 that receives reflected light reflected by an object located in the monitoring area X.

[0026] 1 and 2, the light source 11 emits light that is scanned along a two-dimensional plane that is set as a monitoring area X. The light source 11 in this embodiment is a laser light source that emits laser light, and more specifically, emits pulses of laser light.

[0027] 1 and 2, the sensor scanning means 12 scans the laser light emitted from the light source 11 along the monitoring area X. As shown in Fig. 1, the sensor scanning means 12 of this embodiment has a laser light mirror 14 that reflects the laser light emitted from the light source 11, a rotation shaft 15 connected to the laser light mirror 14, and a power source 16 such as a motor connected to the rotation shaft 15.

[0028] More specifically, the laser light mirror 14 is arranged at an angle relative to the laser light emitted from the light source 11, and by rotating this laser light mirror 14 around the rotation axis 15, the laser light is scanned along the monitoring area X.

[0029] The sensor scanning means 12 may be configured to rotate the light source 11 around a predetermined rotation axis to cause the light emitted from the light source 11 to scan the monitoring area X, and in this case, the sensor scanning means 12 may not be equipped with the laser light mirror 14. The sensor scanning means 12 may also be configured to scan the laser light using an MEMS mirror.

[0030] As shown in FIG. 1, the photodetector 13 detects reflected light reflected by an object present within the monitoring area X, and outputs a detection signal indicating the detection to the control module 30 described below.

[0031] The photodetector 13 in this embodiment receives laser light and is, for example, a photodiode such as an APD (avalanche photodiode). However, the photodetector 13 is not necessarily limited to this and may be changed as appropriate depending on, for example, the type of the light source 11. The photodetector 13 may also be configured to use multiple receiving antennas and detect the angle by detecting the phase difference between the antennas.

[0032] In the above-mentioned sensor module 10, in order to prevent existing objects such as buildings or trees within the monitored area X from being detected as intruding objects, the detection signal output from the photodetector 13 under normal circumstances when no objects are intruding is acquired in advance, and by comparing the normal information indicated by this normal detection signal with the monitoring information indicated by the detection signals successively output from the photodetector 13 during monitoring, it is possible to determine whether an object has intruded into the monitored area X.

[0033] 1 and 2, the camera module 20 captures an image of an object present in a preset imaging area Z, specifically, an image of an object that has entered the above-mentioned monitoring area X. In this embodiment, the imaging area Z is set to be slightly larger than the monitoring area X, as shown in Fig. 2. However, the imaging area Z may be set to be slightly smaller than the monitoring area X, or may be set to be an area that coincides with the monitoring area X.

[0034] This camera module 20 continuously captures images of the monitoring area X regardless of whether or not an object is detected by the above-described sensor module 10. In other words, this camera module 20 acquires moving images of the monitoring area X, and the exposure time at each imaging timing is maintained at a constant time.

[0035] However, the camera module 20 may be, for example, one that acquires a still image of the monitoring area X at the time when the sensor module 10 detects an intruding object, or one that acquires a moving image from that time until a predetermined time has passed.

[0036] This camera module 20 is configured to be able to capture images of objects even in a dark field, such as at night, and specifically, as shown in Figures 1 and 2, it has a dark field light source 21 that enables imaging of a monitoring area X in a dark field, and an imaging unit 22 that captures an image of an object illuminated with illumination light from the dark field light source 21. As shown in Figure 2, the dark field light source 21 emits light at a projection angle (e.g., approximately 5°) that is smaller than the viewing angle of the imaging unit 22 when viewed in a plan view from above. Note that, in this example, the dark field light source 21 is an infrared light source such as an LED that emits infrared light as illumination light into the monitoring area X, but is not necessarily limited to this, and may also be one that emits visible light or the like as illumination light.

[0037] The control module 30 controls the sensor module 10 and the camera module 20, and physically includes a CPU, memory, etc. Functionally, the control module 30 performs at least the functions of a notification unit 31 and a position calculation unit 32, as shown in Fig. 3, by operating the CPU and its peripheral devices in accordance with a monitoring device program stored in the memory.

[0038] As shown in FIG. 3, the notification unit 31 acquires a detection signal from the sensor module 10 (specifically, the photodetector 13) and notifies the user that an object has entered the monitored area X.

[0039] Specifically, the alarm unit 31 is configured to determine whether or not an object has entered the monitoring area X by comparing the normal state information stored in the memory with the monitoring information indicated by the detection signals successively sent from the sensor module 10.

[0040] Furthermore, the notification unit 31 may be configured to transmit a moving image or a still image obtained by the camera module 20 to the user when notifying that an object has entered the monitored area X.

[0041] As shown in FIG. 3, the position calculation unit 32 acquires a detection signal from the sensor module 10 and calculates position information indicating the detected position of an object based on the detection signal.

[0042] This position information is information indicating coordinates that are the detected position of the object, and includes the detected distance that is the distance from the sensor module 10 to the object, and the detected angle of the object relative to the sensor module 10.

[0043] The position calculation unit 32 of this embodiment is physically configured using a TOF (Time of Flight) circuit, etc., and measures the time from when the light source 11 emits a pulse of laser light to when the laser light is reflected by an object and received, and calculates the distance to the detected object by converting this measured time into distance.

[0044] Furthermore, the position calculation unit 32 of this embodiment acquires the detected angle of the object detected from the angle of the laser light received by the photodetector 13 .

[0045] In the above-described configuration, the monitoring device 100 of this embodiment further includes an imaging scanning means 23 capable of scanning the illumination light from the dark field light source 21 along the monitoring area X, as shown in Fig. 4. For the sake of convenience of explanation, the imaging scanning means 23 is omitted from Fig. 1.

[0046] Specifically, as shown in Figure 4, the imaging scanning means 23 has an illumination light mirror 24 that reflects the illumination light emitted from the dark field light source 21, a rotation shaft 25 connected to the illumination light mirror 24, and a power source 26 such as a motor connected to the rotation shaft 25.

[0047] In this embodiment, at least some of the components constituting the sensor scanning means 12 described above are also used as the imaging scanning means 23 .

[0048] More specifically, the rotating shaft 15 connected to the laser light mirror 14 is also used as the rotating shaft 25 connected to the illumination light mirror 24, and the motors connected to these rotating shafts 15 (25) are also used as the sensor scanning means 12 and the imaging scanning means 23.

[0049] In the above-described configuration, the dark field light source 21 is arranged opposite the laser light source 11 that emits laser light, and the illumination light mirror 24 and the laser light mirror 14 are arranged between these light sources 11, 21.In other words, the dark field light source 21, the illumination light mirror 24, the laser light mirror 14, and the laser light source 11 are arranged in this order along the rotation axis 15 (25).

[0050] In this embodiment, illumination light is emitted from the dark field light source 21 along the rotation axis 15 (25) and reflected by the illumination light mirror 24 in a direction perpendicular to the rotation axis 15 (25), and laser light is emitted from the laser light source 11 along the rotation axis 15 (25) and reflected by the laser light mirror 14 in a direction perpendicular to the rotation axis 15 (25).

[0051] In this configuration, the illumination light mirror 24 and the laser light mirror 14 are positioned so that the illumination light and the laser light emitted at the same time are reflected by the illumination light mirror 24 and the laser light mirror 14, respectively, and directed in the same direction.

[0052] Therefore, the control module 30 of this embodiment further functions as a scanning means control unit 33 and a light emission mode control unit 34 .

[0053] During normal monitoring when no intrusion of an object is detected within the monitoring area X, the scanning means control unit 33 controls the sensor scanning means 12 to cause the laser light emitted from the light source 11 to scan along the monitoring area X. On the other hand, during intrusion detection when the intrusion of an object is detected within the monitoring area X, the scanning means control unit 33 controls the imaging scanning means 23 to direct the illumination light emitted from the dark field light source 21 toward the object that has intruded into the monitoring area X.

[0054] During normal monitoring, the scanning means control unit 33 controls the sensor scanning means 12, drives the power source 16 (26), and rotates the laser light mirror 14 around the rotation axis 15 (25), thereby scanning the laser light back and forth within the monitoring area X.

[0055] When detecting an intrusion, the scanning means control unit 33 acquires the position information calculated by the position calculation unit 32 and controls the imaging scanning means 23 based on the detection angle included in the position information. More specifically, the scanning means control unit 33 first identifies the area within the monitoring area X where an object is detected by the sensor module 10 (detection area) based on the acquired detection angle. The scanning means control unit 33 then drives the power source 16 (26) to rotate the illumination light mirror 24 around the rotation axis 15 (25) so that the illumination light emitted from the dark field light source 21 is directed only toward the identified detection area. Note that "directing (or emitting) the illumination light only toward the detection area" means that the illumination light is emitted only toward the identified detection area when viewed from above in a plan view. That is, the sensor module 10 of this embodiment is configured to scan laser light along a two-dimensional plane parallel to the horizontal plane, but this means that, as long as it is within the detection area when viewed from above, the illumination light from the dark field light source 21 may not only be emitted along this two-dimensional plane, but may also be emitted into an area including above and below the two-dimensional plane. In other words, this means that illumination light may be emitted not only into the two-dimensional detection area of ​​the sensor module 10, but also into surrounding areas above and below the detection area.

[0056] The light emission mode control unit 34 controls the dark field light source 21 to control the light emission mode of the illumination light emitted from the dark field light source 21. The light emission mode includes the intensity, light emission time, or blinking cycle of the illumination light. For example, the light emission mode control unit 34 may cause the dark field light source 21 to emit light multiple times in accordance with the detection target. Furthermore, when the area of ​​the detection target is larger than the area of ​​the illumination light, the light emission mode control unit 34 may cause the dark field light source 21 to emit light multiple times in accordance with the imaging size of the detection target.

[0057] The light emission mode control unit 34 of this embodiment is configured to turn off the dark field light source 21 during normal monitoring and to cause the dark field light source 21 to emit light only when an intrusion is detected. Here, the light emission mode control unit 34 acquires scanning information from the scanning means control unit 33 and causes the dark field light source 21 to emit illumination light only when the illumination light emitted from the dark field light source 21 is directed toward the detection area. Here, the light emission mode control unit 34 controls the dark field light source 21 to emit pulsed light as illumination light for a certain period of time. However, without being limited to this, the light emission mode control unit 34 may cause the illumination light to be emitted from the timing when an intrusion of an object into the monitored area X is detected, or may cause the illumination light to be emitted after a predetermined time has elapsed since the timing when an intrusion of an object into the monitored area X is detected.

[0058] In this embodiment, the illumination light mirror 24 and the laser light mirror 14 are disposed in such an orientation that the illumination light and the laser light emitted at the same timing are reflected by the illumination light mirror 24 and the laser light mirror 14, respectively, and head in the same direction, so that the illumination light emitted from the dark field light source 21 heads toward the detection area when an object is detected intrusion into the monitoring area X. Therefore, when the monitoring device 100 of this embodiment detects an object intrusion into the monitoring area X, the scanning means control unit 33 immediately causes the dark field light source 21 to emit illumination light without rotating the illumination light mirror 24.

[0059] [Effects of the monitoring device 100 of this embodiment] The monitoring device 100 configured in this manner is equipped with an imaging scanning means 23 that can scan the illumination light emitted from the dark field light source 21 along the monitoring area, so there is no need to arrange the dark field source in various directions in the monitoring area X, and it is possible to reliably image an intruder into the monitoring area X regardless of their position without increasing the number of light sources installed.

[0060] In addition, the illumination light from the dark field light source 21 is scanned by the imaging scanning means 23 and is emitted only to a part of the monitoring area X, that is, the detection area where an object is detected by the sensor module 10, thereby reducing power consumption due to the irradiation of the illumination light.

[0061] Furthermore, since the rotation axis 15 (25) and power source 16 (26) are shared between the sensor scanning means 12 and the imaging scanning means 23, the number of parts can be reduced, making it possible to make the device smaller and less expensive.

[0062] In addition, since the illumination light emitted from the dark field light source 21 is pulsed light, the power consumption due to irradiation of the illumination light can be reduced.

[0063] [Other Embodiments] The present invention is not limited to the above-described embodiments.

[0064] For example, in another embodiment, a mirror that reflects light from each light source may be shared between the sensor scanning means 12 and the imaging scanning means 23. For example, as shown in Fig. 5, the laser light mirror 14 may be configured as a double-sided mirror, and the back surface of the reflective surface that reflects the laser light emitted from the laser light source 11 may be configured to reflect the illumination light emitted from the dark-field light source 21. In this way, the rotation shaft 15 (25), motor 16 (26), and mirror 14 (24) are shared, thereby reducing the number of parts.

[0065] 5 and 6, the camera module 20 may include a plurality of dark-field light sources 21 arranged with their optical axes aligned. In this case, the imaging scanning means 23 is preferably configured to be able to scan the illumination light emitted from each of the plurality of dark-field light sources 21 along the monitoring area X. In this way, since the camera module 20 includes a plurality of dark-field light sources 21, the amount of illumination light irradiated onto an object intruding into the monitoring area X can be increased, allowing the intruder to be imaged more clearly.

[0066] In another embodiment, the light emission mode control unit 34 may be configured to adjust the height or angle of the illumination light emitted from the camera module 20 depending on the position or size of an object detected within the monitoring area X. For example, if the camera module 20 has multiple dark field light sources 21 that emit illumination light at different heights or angles into the monitoring area X, only some of the multiple dark field light sources 21 may be turned on depending on the position or size of the detected object. In this way, it is possible to reliably capture an image of an object detected within the monitoring area X while suppressing power consumption due to irradiation with illumination light.

[0067] In another embodiment, the laser light mirror 14 and the illumination light mirror 24 constituting each of the scanning means 12, 23 may be configured as a polygonal mirror having multiple mirror surfaces (e.g., four or six surfaces). In this case, the polygonal mirror 24 may be shared between the sensor scanning means 12 and the imaging scanning means 23. In this case, the polygonal mirror 24 may be arranged so that each mirror surface rotates around the rotation axis 15 (25), and the laser light source 11 and the dark-field light source 21 may be arranged so that light is emitted toward the polygonal mirror 24, perpendicular to the rotation axis 15 (25). The laser light source 11 and the dark-field light source 21 may be arranged to face the same direction as shown in FIG. 7 or may be arranged to face each other across the polygonal mirror 24 as shown in FIG. 8.

[0068] In yet another embodiment, the monitoring device 100 may further include a visible light source that emits visible light into the monitoring area X, and may be configured to irradiate the visible light from the visible light source onto an object detected by the sensor module 10. In this case, the monitoring device 100 may include a visible light scanning means that can scan the visible light from the visible light source along the visible area, and the visible light may be scanned by the visible light scanning means, thereby emitting visible light into the detection area where an object is detected by the sensor module. In this case, it is possible to intimidate an intruder into the monitoring area X by irradiating the intruder with visible light.

[0069] In the above embodiment, the camera module 20 is configured to turn off the dark field light source 21 during normal surveillance and to emit light only when an intrusion is detected, but this is not limiting. In other embodiments, the camera module 20 may always emit light from the dark field light source 21, regardless of whether the camera module 20 is performing normal surveillance or detecting an intrusion.

[0070] In the above embodiment, the sensor module 10 was a LiDAR sensor, but it may also be configured to emit radio waves into the monitoring area X and detect the radio waves reflected back by an object entering the monitoring area X. In this case, the present invention would be useful as a RaDAR sensor. Such a sensor module 10 may have a radiator that emits electromagnetic waves such as millimeter waves or microwaves, and may employ a ranging method such as FMCW, and an angle control method such as MIMO or phased array. In this case, the scanning means 12 may be a mechanical scanning type or an electronic scanning type. A specific example of an electronic scanning type is a method in which signals from multiple receiving antennas are combined by changing the phase using hardware or software.

[0071] Furthermore, the present invention is not limited to the above-described embodiment, and it goes without saying that various modifications are possible without departing from the spirit of the invention.

[0072] According to the present invention, it is possible to reliably capture an image of an intruder into a monitored area X regardless of his or her position without increasing the number of dark field light sources required to enable dark field imaging.

[0073] REFERENCE SIGNS LIST 100 Monitoring device 10 Sensor module 12 Sensor scanning means 14 Laser light mirror 15 Rotation shaft 16 Motor 20 Camera module 21 Dark field light source 22 Imaging means 23 Imaging scanning means 24 Illumination light mirror 25 Rotation shaft 26 Motor X Monitoring area

Claims

1. A surveillance device comprising: a sensor module that detects an object that has entered a predetermined surveillance area by emitting light or radio waves into the surveillance area and detecting the light or radio waves that have been reflected back from the surveillance area; a camera module having a dark field light source to enable imaging of the surveillance area in a dark field and an imaging means for imaging the object illuminated with illumination light from the dark field light source; and an imaging scanning means capable of scanning the illumination light along the surveillance area.

2. A monitoring device as described in claim 1, wherein the illumination light from the dark field light source is scanned by the imaging scanning means so as to be emitted only to a detection area which is a part of the monitoring area and in which an object is detected by the sensor module.

3. A monitoring device as described in claim 1, characterized in that the sensor module has a sensor scanning means that scans the monitoring area with laser light, and at least a portion of the components constituting the sensor scanning means are also used as the imaging scanning means.

4. A monitoring device as described in claim 3, wherein the sensor scanning means has a laser light mirror that reflects the laser light, a rotating shaft connected to the laser light mirror, and a motor connected to the rotating shaft, and the imaging scanning means has an illumination light mirror that reflects the illumination light, and the rotating shaft is connected to the illumination light mirror.

5. A monitoring device as described in claim 3, wherein the sensor scanning means has a mirror that reflects the laser light, a rotating shaft connected to the mirror, and a motor connected to the rotating shaft, and the mirror is a double-sided mirror that also serves as the imaging scanning means, and reflects the illumination light with the back surface of the reflective surface that reflects the laser light.

6. A surveillance device as described in claim 1, wherein the camera module has a plurality of the dark field light sources, and the imaging scanning means is capable of scanning the illumination light emitted from each of the plurality of dark field light sources along the surveillance area.

7. A monitoring device according to claim 1, wherein the illumination light emitted from the dark field light source is pulsed light.

8. The monitoring device according to claim 1, further comprising a visible light source that emits visible light into the monitoring area, wherein the object detected by the sensor module is irradiated with the visible light from the visible light source.

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