Laser Scan Sensor

Abstract

This laser scanning sensor (100) comprises: a laser range finder (110); a scanning mechanism (120); a distance data acquisition unit (130); a memory (160); an object detection processing unit (135); an object detection area determination unit (140) that, on the basis of a determined result from the object detection processing unit, determines whether or not a detection object (15) is respectively present in a caution area (B100) and a determination area (C100); an object detection area alert control unit (145) that controls whether or not to issue an alert when a detection object (15) is present in the caution area (B100), on the basis of the determined results from the object detection processing unit (135) and the object detection area determination unit (140); and an alert output control unit (150).

Description

[Technical field]

[0001] The present invention relates to a laser scan sensor that detects intruders and the like within the premises of a building, and in particular to a laser scan sensor that can more accurately limit the surveillance area required during times when there is a high traffic of related persons, without manual operation, connection to an external device, or time linkage. [Background technology]

[0002] Conventionally, a laser scan sensor has been proposed that uses a laser rangefinder that uses laser light as a light source and can accurately detect intruders that should be detected, even if a car or other vehicle enters and parks in the alert area after it has been set, or if a new harmless obstacle is installed (see, for example, Patent Document 1).

[0003] This "laser scan sensor" comprises a laser range finder 110, a scan mechanism 120, a distance data acquisition unit 130, a memory 160 for storing installation state information and detection area information for each measurement direction, a human body determination unit 140 for extracting from the acquired distance data parts of an intruding or moving object that are determined by comparing the distance data with the detection area information and that may correspond to a human body, and excluding the extracted parts whose movement distance within a predetermined distance within a predetermined time based on the movement status of each extracted part in a time series, and determining whether each of the remaining extracted parts is a human body or not, and a detection area information update unit 150 for updating the detection area information under predetermined conditions. Department and , and a warning output control unit 150. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5263692 Summary of the Invention [Problem to be solved by the invention]

[0005] 19(a) and (b) are schematic diagrams of a detection area A900 formed by a conventional laser scan sensor 900, where (a) illustrates an example of a late-night security situation, and (b) illustrates an example of a daytime security situation.

[0006] As shown in Fig. 19(a), the entire detection area A900 can be monitored late at night when there is no traffic of related persons 10. However, during the daytime when there is a lot of traffic of related persons 10, it is necessary to limit the monitoring range by excluding the entrance / exit 20 and its surroundings using a mask function or the like (disabling the object detection function) as shown in Fig. 19(b). To change the settings for this purpose, it is necessary to manually operate a DIP switch or the like provided in advance in the laser scan sensor 900, or to communicate with an external device connected by wire or wirelessly, or to automatically change the settings in conjunction with the time of day, etc.

[0007] In view of these problems with the conventional technology, an object of the present invention is to provide a laser scan sensor that can dynamically set or enable / disable a surveillance range in accordance with ever-changing situations without the need for manual operation or the use of external devices. [Means for solving the problem]

[0008] In order to achieve the above object, the laser scan sensor of the present invention comprises a laser rangefinder that emits laser light and measures the distance to an object based on the time it takes for the reflected light from the object to return in that direction; a scanning mechanism that changes the measurement direction of the laser rangefinder; a distance information acquisition unit that periodically performs measurements with the laser rangefinder while changing the measurement direction using the scanning mechanism to form a detection area and acquires distance information for each of the measurement directions within the detection area in chronological order; an information storage unit that stores reference distance information for each of the measurement directions as detection area information and stores at least one security area that is set as an area to be actually monitored within the detection area and a judgment area that is set corresponding to each security area; and The present invention is characterized in that it comprises an object detection processing unit that extracts portions that may correspond to a detection target object from the distance information acquired by the acquisition unit, and determines whether or not each extracted portion is the detection target object based on the chronological movement status of each extracted portion; an object detection area determination unit that determines whether or not the detection target object is present in the alert area and the determination area, respectively, or whether or not the detection target object is present in the determination area, based on the determination results of the object detection processing unit; an alarm control unit that controls whether or not to issue an alarm when the detection target object is present in the alert area, based on the determination results of the object detection processing unit and the object detection area determination unit; and an alarm output control unit that outputs an alarm signal in accordance with the control by the alarm control unit.

[0009] A laser scan sensor configured in this way can dynamically set or enable / disable the surveillance area according to the ever-changing situation without manual operation or the use of external devices, etc. Furthermore, it can also identify the detection target, such as detecting only objects with a specific shape or objects moving in a specific direction.

[0010] In the laser scan sensor of the present invention, the alert control unit may control the sensor to alert if the detection target object is present in the security area when the detection target object is present in the determination area, and may control the sensor to suppress alert even if the detection target object is present in the security area when the detection target object is not present in the determination area. Alternatively, the alert control unit may control the sensor to suppress alert even if the detection target object is present in the security area when the detection target object is present in the determination area, and may control the sensor to alert if the detection target object is present in the security area when the detection target object is not present in the determination area. Which control to use may be determined depending on the installation location and the detection target object.

[0011] A laser scan sensor configured in this way can appropriately select which control to use, thereby providing appropriate vigilance according to the installation location, the object to be detected, and the like.

[0012] In addition, in the laser scan sensor of the present invention, the information storage unit is capable of storing whether the alarm control unit will perform control in a first control mode or a second control mode, and the alarm control unit, if the first control mode is stored in the information storage unit, controls to issue an alarm if the detection target object is present in the security area when the detection target object is present in the judgment area, and if the detection target object is not present in the judgment area, controls to suppress issuing an alarm even if the detection target object is present in the security area; and, if the second control mode is stored in the information storage unit, controls to suppress issuing an alarm if the detection target object is present in the security area when the detection target object is present in the judgment area, and controls to issue an alarm if the detection target object is present in the security area when the detection target object is not present in the judgment area.

[0013] A laser scan sensor having such a configuration can provide appropriate protection according to the installation location, the object to be detected, etc., simply by rewriting the memory in the information storage unit.

[0014] In the laser scan sensor of the present invention, the alarm control unit may continue to control the presence of the detection target object within the determination area for a predetermined first predetermined time even if the detection target object that was present within the determination area disappears, or the alarm control unit may hold off on issuing an alarm for a predetermined second predetermined time even if the detection target object is detected within the security area.

[0015] A laser scan sensor configured in this way can provide more appropriate surveillance depending on the installation location, the object to be detected, etc.

[0016] In addition, the laser scan sensor of the present invention may further include a display, and the alarm output control unit may cause the display to display when the alarm output control unit has performed control to suppress alarm output. Alternatively, the alarm output control unit may notify the outside of alarm information for the confirmed alert area.

[0017] In addition, the laser scan sensor of the present invention may further include an operation unit that can select either an external input or an image processing result, and the alarm control unit may treat the presence of the object to be detected in the previously associated judgment area as depending on either the external input or the image processing result selected by the operation unit.

[0018] In addition, the laser scan sensor of the present invention further includes an image pickup device, and the alarm control unit Recording The distance information corresponding to the position of the target object detected in the captured image based on the image processing results of the captured image by the imaging device may be obtained, and whether or not to issue an alarm may be controlled when the target object is present within the surveillance area. Effect of the Invention

[0019] The laser scan sensor of the present invention makes it possible to dynamically set or enable / disable the surveillance area according to the ever-changing situation without manual operation or the use of external devices, etc. Furthermore, it also makes it possible to identify the detection target, such as detecting only objects of a specific shape or objects moving in a specific direction. [Brief description of the drawings]

[0020] [Figure 1] 1 is a block diagram showing a schematic configuration of a laser scan sensor 100 according to a first embodiment of the present invention. [Diagram 2] 2 is a schematic plan view showing a detection area A100 formed by a laser scan sensor 100. FIG. [Diagram 3] 1 is a schematic explanatory diagram illustrating a warning area B100 and a determination area C100 formed within a detection area A100 of a laser scan sensor 100. FIG. [Figure 4] 13A to 13D are explanatory diagrams of alarm control in two modes for setting an action for controlling whether or not the laser scan sensor 100 issues an alarm, that is, an alarm promotion mode and an alarm suppression mode. [Diagram 5] 10 is a time chart illustrating an example of timing settings for evaluating an object detection state in a security area B100 and a determination area C100 by the laser scan sensor 100. [Figure 6] 4 is a time chart illustrating a determination extension time and an alarm waiting time that are set to adjust the timing of starting the determination operation of the laser scan sensor 100. [Figure 7] FIG. 1 is a schematic explanatory diagram of an example of use in which trucks 16 are detected separately from other passenger vehicles 17 in a parking space reserved for trucks. [Figure 8] FIG. 1 is a schematic explanatory diagram of an example of use for detecting car break-ins in a parking lot or the like. [Figure 9] FIG. 1 is a schematic explanatory diagram of an example of use for detecting an intruder 11 inside the premises of a building or the like. [Figure 10]FIG. 1 is a schematic explanatory diagram of an example of use for detecting an intruder 11 under surveillance by a security guard at an entrance to the premises of a building or the like. [Figure 11] 4 is a flowchart showing the overall processing of the laser scan sensor 100. [Figure 12] 1A is a flowchart showing the judgment / alert area alarm information update subroutine, FIG. 1B is a flowchart showing the judgment extension time processing subroutine, FIG. 1C is a flowchart showing the alarm waiting time processing subroutine, and FIG. 1D is a flowchart showing the judgment processing subroutine. [Figure 13] 11 is a flowchart relating to a determination operation, in which (a) is a flowchart showing a constant processing subroutine, and (b) is a flowchart showing a processing subroutine during an alarm standby time. [Figure 14] 11 is a flowchart relating to an action, in which (a) is a flowchart showing a promotion processing subroutine, and (b) is a flowchart showing a suppression processing subroutine. [Figure 15] 13 is a flowchart showing an alarm output subroutine. [Figure 16] 10A is a front view of a laser scan sensor 200 according to a second embodiment of the present invention, and FIG. 10B is a schematic plan view comparing an imaging range R201 captured by a built-in camera 201 with a laser irradiation range R202. [Figure 17] 16(a) is a schematic diagram illustrating an image captured by the built-in camera 201 when installed horizontally, and (b) is a schematic plan view illustrating step numbers within the laser irradiation range R202 in FIG. 16(b). [Figure 18] 1A is a schematic explanatory diagram of a laser scan image when a vertically installed laser scan sensor 200 detects an intruding object, and FIG. 1B is a schematic diagram illustrating an image captured by a built-in camera 201. FIG. [Figure 19] 13A and 13B are schematic diagrams illustrating a detection area A900 formed by a conventional laser scan sensor 900, where (a) illustrates an example of a late-night security situation, and (b) illustrates an example of a daytime security situation. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0022] First Embodiment 1.1 Schematic configuration of the laser scan sensor 100 Fig. 1 is a block diagram showing a schematic configuration of a laser scan sensor 100 according to a first embodiment of the present invention. Fig. 2 is a schematic plan view showing a detection area A100 formed by this laser scan sensor 100. Note that in Fig. 2, the interval between adjacent distance measurement directions is drawn much wider than the actual interval, but this is for the convenience of explanation only.

[0023] As shown in FIG. 1, the laser scan sensor 100 includes a laser rangefinder 110, a scanning mechanism 120, a distance data acquisition unit 130, an object detection processing unit 135, an object detection area determination unit 140, an object detection area alarm control unit 145, an alarm output control unit 150, and a memory 160.

[0024] The laser rangefinder 110 emits a pulsed laser beam and precisely measures the distance to an object by precisely measuring the minute time it takes for the reflected light from the object in the direction of the laser beam. The light-emitting element of the laser beam in the laser rangefinder 110 may be, for example, a semiconductor laser diode (LD). The light-receiving element may be, for example, an avalanche photodiode (APD). It is desirable to provide a dedicated hardware circuit for controlling the driving of the light-emitting element and measuring the time it takes for the reflected light to return. A general feature of a laser rangefinder is that it can precisely measure distances up to a fairly long distance, for example, up to several tens of meters, and in some cases, even much longer distances. However, the maximum detection distance of the laser rangefinder 110 is set to 30 meters.

[0025] The scanning mechanism 120 is rotatable by incorporating a motor (not shown) and is mechanically connected to at least a part of the laser rangefinder 110 so as to change the direction (angle) of distance measurement by the laser rangefinder 110. For example, a configuration in which only the optical system part of the laser rangefinder 110 is rotated is conceivable, but a configuration in which the entire laser rangefinder 110 is rotated or another configuration is also acceptable. Then, by rotating the scanning mechanism 120 in a predetermined direction at a constant speed, the direction of distance measurement by the laser rangefinder 110 changes in conjunction with the rotation of the scanning mechanism 120.

[0026] 2 by periodically repeating measurements by the laser range finder 110 while changing the measurement direction by the scanning mechanism 120, and acquiring distance data for each measurement direction (also called "step") at predetermined angular intervals within the detection area A100 in time series at predetermined time intervals. Note that the distance data for each measurement direction acquired immediately after the distance data acquisition unit 130 starts operating or after a certain time has elapsed is stored in the memory 160 as reference distance data.

[0027] For example, if the scanning period T of the scanning mechanism 120 is 50 ms (20 scans per second), and the pulse laser light is emitted in a range of 180 degrees, which is half of one rotation, to measure the distance, the pulse width of the pulse laser light is 10 ns, and the emission period is 34.7 μs, then 720 distance measurements can be made in a range of 180 degrees. In this case, the angular interval of the distance measurement is 0.25 degrees, which is only about 13 cm even at a distance of 30 m as shown in FIG. 2, so that the spatial resolution in the detection area A100 is quite high. Therefore, it is possible to fairly accurately identify the position, size (width), shape, etc. of the detected object based on the distance data acquired by the distance data acquisition unit 130 and determine whether or not it is a human body, and even if multiple human bodies exist in the detection area A100, it is also possible to identify them individually. Such distance data is obtained every 50 ms, which is the scanning period T. Note that the values ​​shown here are merely examples.

[0028] 2 shows a case where the laser rangefinder 110 is installed horizontally and the measurement direction is changed parallel to the ground by the scanning mechanism 120 while the measurement by the laser rangefinder 110 is periodically repeated, but the installation state is not limited to this. For example, the laser rangefinder 110 may be installed at a certain height from the ground and facing directly downward or diagonally downward. In this case, if information on such an installation state, specifically the installation height and distance measurement direction, etc., is stored in the memory 160, the height of the target object can also be calculated by referring to these information.

[0029] The object detection processing unit 135 first analyzes the distance data acquired by the distance data acquisition unit 130. By comparing the distance data for each measurement direction with the corresponding reference distance data stored in the memory 160, it is possible that an object has entered into the measurement direction in which the distance data has changed, or that an object that was already present has moved. Then, by performing two-dimensional expansion based on each measurement direction of the distance data, a portion that is presumed to correspond to the shape of the object to be detected is extracted based on the shape and range of the object that has entered or moved.

[0030] Since the distance data is acquired in time series by the distance data acquisition unit 130, next, the movement situation is grasped by determining how the part that is assumed to be a detection target object and extracted in the distance data changes in the distance data thereafter. When the movement trajectory is significantly discontinuous, it can be determined that there is a high possibility that it is not a detection target object. On the other hand, when the object is completely still or the movement distance is very short, it can be determined that it is at least not an intruder that should be guarded against. Furthermore, by taking into consideration the movement direction, etc., it is possible to more accurately determine whether the object is an intruder that should be guarded against or simply a passerby walking near the boundary of the detection area A100. The above determination results are combined to determine whether a detection target object such as a human body that should be guarded against exists.

[0031] The object detection area determination unit 140 determines whether or not a detection target object 15 exists in each of the alert area B100 (described later with reference to FIG. 3) and the determination area C100 (described later with reference to FIG. 3) based on the determination result by the object detection processing unit 135. Alternatively, the object detection area determination unit 140 may determine only whether or not a detection target object 15 exists in the determination area C100 based on the determination result by the object detection processing unit 135. When multiple alert areas B100 exist, a corresponding determination area C100 also exists, and a determination is made for each of them.

[0032] Note that the condition for judgment is not limited to whether or not a detection target object 15 exists within the judgment area C100, and for example, an external input terminal provided on the laser scan sensor 100 may be used as the judgment condition. Specifically, it may be used for applications such as disabling a specific security area by an operation by a security guard. Also, as will be described later with reference to Figs. 16 to 18, it is also conceivable to use the image processing results of an image acquired by a built-in camera as the judgment condition. Furthermore, a switch or the like may be provided so that it is possible to select whether to use the external input terminal or the built-in camera.

[0033] The object detection area reporting control unit 145 controls whether or not to report when a detection target object 15 exists within the security area B100, based on the respective determination results of the object detection processing unit 135 and the object detection area determination unit 140. Specifically, there are two modes for setting the following actions (described later with reference to Figs. 4(a) to (d)).

[0034] [Alarm promotion mode] When a detection target object 15 is present within the judgment area C100, the system is controlled to issue an alarm if a detection target object 15 is also present within the alert area B100, and when a detection target object 15 is not present within the judgment area C100, the system is controlled to suppress the issue of an alarm even if a detection target object 15 is present within the alert area B100.

[0035] [Alarm suppression mode] When a detection target object 15 is present within the judgment area C100, control is performed to suppress the issuance of an alarm even if a detection target object 15 is present within the alert area B100, and when a detection target object 15 is not present within the judgment area C100, control is performed to issue an alarm if a detection target object 15 is present within the alert area B100.

[0036] It is preferable to be able to select which of these modes to apply as necessary. For example, the mode to be applied may be stored in memory 160, and control may be performed according to the mode that corresponds to the stored mode.

[0037] Also, for example, when it is desired to disable a specific security area B100 by manual operation, a switch for this purpose may be provided and connected to this object detection area reporting control unit 145 as an external input.

[0038] The alarm output control unit 150 may output an alarm signal to an output terminal or display an LED when the object detection area determination unit 140 determines that an object is present in the security area B100. Alternatively, the alarm output control unit 150 may notify the outside of the determined security area B100 via Ethernet. However, the output destination and output method are not limited to these.

[0039] It is preferable that distance data acquisition unit 130, object detection processing unit 135, object detection area determination unit 140, object detection area report control unit 145, report output control unit 150, and memory 160 are configured, for example, by a one-chip microcomputer for embedding in equipment and its software processing. Since each of the above-mentioned determination processes can be realized by a method such as pattern matching, a relatively inexpensive one-chip microcomputer can be adopted, which contributes to reducing the cost of the laser scan sensor 100 as a whole. However, it is not necessary to use a one-chip microcomputer.

[0040] 1.2 Basic operation of the laser scan sensor 100 FIG. 3 is a schematic explanatory diagram illustrating a warning area B100 and a determination area C100 formed within a detection area A100 of the laser scan sensor 100. As shown in FIG.

[0041] Here, the alert area B100 is set as an area within the detection area A100 where one actually wants to be alerted to the intrusion of the object 15. The judgment area C100 is set as an area used to control object detection within the alert area B100, and an alarm will not be issued simply because an object 15 has been detected within this judgment area C100 itself. In other words, according to the detection result of the object 15 within the judgment area C100, an alarm can be issued in response to the object 15 detected within the alert area B100, or conversely, the issuance of an alarm can be suppressed.

[0042] 4(a) to 4(d) are explanatory diagrams of two modes, namely, an alarm promotion mode and an alarm suppression mode, for setting actions to control whether or not the laser scan sensor 100 issues an alarm. Note that, at the time of installation, one of these two modes is set according to the installation location and installation target, and one or more necessary alert areas B100 and corresponding judgment areas C100 are appropriately set.

[0043] [Alarm promotion mode] In this mode, when an object 15 is detected within the judgment area C100, an alarm is issued if an object 15 is also detected within the security area B100 as shown in FIG. 4(a).

[0044] On the other hand, as shown in FIG. 4(b), if no object 15 is detected within the determination area C100, the issuance of an alarm is suppressed even if an object 15 is detected within the alert area B100.

[0045] [Alarm suppression mode] In this mode, when an object 15 is detected within the determination area C100, an alarm is suppressed even if an object 15 is detected within the security area B100, as shown in FIG. 4(c).

[0046] On the other hand, if no object 15 is detected in the judgment area C100 as shown in FIG. 4(d), an alarm is issued when an object 15 is detected in the alert area B100.

[0047] 5 is a time chart illustrating an example of timing settings for evaluating the object detection state in the alert area B100 and the judgment area C100 by the laser scan sensor 100. Note that the judgment operation can be set to either an operation in which judgment is performed only during the alarm standby time or an operation in which judgment is performed constantly, and this time chart corresponds to the former operation.

[0048] The laser scan sensor 100 evaluates the object detection state in the security area B100 and the judgment area C100 only during the alarm standby time, according to the action settings that were preset at the time of installation, etc. As shown in the waveform on the left side of Figure 5, after the alarm standby time has elapsed, the evaluation result is held and the alarm signal output continues until the object 15 in the security area B100 disappears.

[0049] As shown in the central waveform of Figure 5, even if object 15 disappears from the security area B100 during the alarm waiting time, if the alarm condition is met during the alarm waiting time, it is preferable to issue an alarm for a short period of time to notify the user that the alarm condition has been met.

[0050] Furthermore, as shown in the waveform on the right side of Figure 5, if object 15 is not detected in judgment area C100, even if object 15 is detected in alert area B100, if the state in which object 15 is not detected in judgment area C100 continues even after the alarm waiting time has elapsed, alarm activation will be suppressed.

[0051] On the other hand, it is also possible to set the device to operate so as to constantly evaluate the object detection state in the alert area B100 and the determination area C100.

[0052] FIG. 6 is a time chart explaining the judgment extension time and the alarm waiting time that are set to adjust the timing at which the judgment operation of the laser scan sensor 100 starts, where FIG. 6(a) shows the judgment extension time and FIG. 6(b) shows the alarm waiting time.

[0053] The judgment extension time is the time during which the state in which the object 15 in the judgment area C100 remains present continues even if the object 15 detected in the judgment area C100 disappears, as shown in FIG. 6(a).

[0054] On the other hand, the alarm standby time is a time during which an alarm for the security area B100 is held in a standby state even if an object 15 is detected in the security area B100, as shown in FIG. 6(b).

[0055] 1.3 Example of using the Laser Scan Sensor 100 FIG. 7 is a schematic explanatory diagram of an example of use in which trucks 16 are detected separately from other passenger cars 17 in a parking space for trucks.

[0056] 7, the laser scan sensor 100 is installed facing downward above the parking space, and the detection area A100 is formed in the vertical direction. The alert area B100 is formed in a rectangular shape from the ground to a certain height (lower than the height of the truck 16 and higher than the height of the passenger car 17), and the judgment area C100 is formed in a rectangular shape adjacent to and above the alert area B100.

[0057] The setting values ​​for each setting item are as follows.

[0058] Action: Suppress alarm Operation: During alarm standby time Judgment condition: Judgment area Alarm standby time: 2 seconds judgement extension Time: 0 seconds In this example, when truck 16 enters a parking space reserved for trucks, the low cabin at the front enters the surveillance area B100 first, and the high cargo bed at the rear is detected after a short delay.

[0059] If the vehicle 17 does not reach the judgment area C100, an alarm is issued, but if the truck 16 reaches the judgment area C100, no alarm is issued.

[0060] FIG. 8 is a schematic explanatory diagram of an example of use for detecting car break-ins in parking lots, etc.

[0061] As shown in FIG. 8, the laser scan sensor 100 is installed facing inward at the edge of a parking lot, and a detection area A100 is formed in the horizontal direction. Judgment area C100 The parking space is formed in a rectangular shape corresponding to the parking space for the car 17, and is surrounded by a Security Area B100 is formed.

[0062] The setting values ​​for each setting item are as follows.

[0063] Action: Promote reporting Operation: During alarm standby time Judgment condition: Judgment area Alarm standby time: 300 seconds (5 minutes) judgement extension Time: 0 seconds In this example of use, if a car 17 is parked in the determination area C100 and a thief 11 enters the security area B100 and remains near the car 17 for five minutes or more, an alarm is issued.

[0064] Even if the thief 11 has disappeared within five minutes, an alarm will be sounded for a short time to notify the presence of some object 15 in the security area B100.

[0065] If there is no vehicle 17 in the judgment area C100 for more than 5 minutes, 11 Even if exists, no report is issued.

[0066] FIG. 9 is a schematic explanatory diagram of an example of use for detecting an intruder 11 inside the premises of a building or the like.

[0067] As shown in Fig. 9, the laser scan sensor 100 is installed facing the side wall 21 of the passageway leading to the premises, and the detection area A100 is formed in the horizontal direction. The security area B100 is formed in a rectangular shape in a section of the passageway of a predetermined length, and the judgment area C100 is formed in a rectangular shape adjacent to it from the outside side (the opposite side to the premises direction indicated by the thick arrow in the figure). Note that the judgment area C100 is formed relatively smaller than the security area B100 so that the passing time is shorter.

[0068] The setting values ​​for each setting item are as follows.

[0069] Action: Promote reporting Operation: Always Judgment condition: Judgment area Alarm standby time: 0 seconds judgement extension Time: 5 seconds In this example, people entering the premises (in the direction of the thick arrow in the figure) are 11 If so, an alarm will be sounded and people will be asked to leave the premises. 11 If so, no report will be issued.

[0070] FIG. 10 is a schematic explanatory diagram of an example of use in which an intruder 11 is detected under the surveillance of a security guard at an entrance to the premises of a building or the like.

[0071] As shown in Fig. 10, similar to Fig. 9, the laser scan sensor 100 is installed facing the side wall 21 of the passageway to the premises, on the opposite side of the passageway, and the detection area A100 is formed in the horizontal direction. The alert area B100 is also formed in a rectangular shape in a section of the passageway of a predetermined length. On the other hand, the judgment area C100 is formed in a rectangular shape near the alert area B100 and at the location of the security guard 12.

[0072] The setting values ​​for each setting item are as follows.

[0073] Action: Suppress alarm Operation: Always Judgment condition: Judgment area Alarm standby time: 5 seconds judgement extension Time: 0 seconds In this example, when guard 12 is standing in judgment area C100, 11 No alarm will be issued even if the vehicle passes through the alert area B100.

[0074] When guard 12 leaves the judgment area C100, an intruder 11 If guard 12 enters security area B100 and passes through it for 5 seconds, an alarm is triggered. However, if guard 12 returns to judgment area C100 within 5 seconds, no alarm is triggered.

[0075] 1.4 Processing flow of the laser scan sensor 100 FIG. 11 is a flowchart showing the overall processing of the laser scan sensor 100.

[0076] As shown in FIG. 11, first, judgment / alert area object presence / absence information recording is performed (step S1), then the judgment / alert area alarm information update subroutine is called (step S2), and finally the alarm output subroutine is called (step S3) to terminate the overall processing.

[0077] Figure 12(a) is a flowchart showing the judgment / alert area alarm information update subroutine, Figure 12(b) is a flowchart showing the judgment extension time processing subroutine, Figure 12(c) is a flowchart showing the alarm waiting time processing subroutine, and Figure 12(d) is a flowchart showing the judgment processing subroutine.

[0078] In the judgment / alert area alarm information update subroutine shown in FIG. 12(a), first, a judgment extension time processing subroutine is called (step S21), an alarm standby time processing subroutine is called (step S22), and a judgment processing subroutine is called (step S23).

[0079] Next, it is determined whether or not there is any remaining security area (step S24), and if the determination result is YES, the process returns (step S25), whereas if the determination result is NO, the process returns to step S21.

[0080] In the judgment extension time processing subroutine shown in Fig. 12(b), first, it is determined whether the object in the judgment area has changed from presence to absence (step S211). If the judgment result is YES, the judgment extension time measurement is started (step S212) and then the process proceeds to step S213, and if the judgment result is NO, the process proceeds directly to step S213.

[0081] Next, it is determined whether or not it is within the extended judgment time (step S213), and if the judgment result is YES, the judgment area is overwritten with "present" (step S214) and then the process returns (step S215), and if the judgment result is NO, the process proceeds directly to step S215 and returns.

[0082] 12(c), first, it is determined whether the object in the security area has changed from absent to present (step S221). If the determination result is YES, measurement of the alarm standby time is started (step S222), the alarm standby object presence flag is set to "absent" (step S223), and the process proceeds to step S224. If the determination result is NO, the process proceeds directly to step S224.

[0083] Next, it is determined whether it is within the alarm standby time (step S224), and if the determination result is YES, the alert area object is overwritten to "absent" (step S225) before proceeding to step S226, and if the determination result is NO, the process proceeds directly to step S228 and returns. Furthermore, it is determined whether there is an object in the determination area (step S226), and if the determination result is YES, the alarm standby object appearance flag is set to "present" (step S227) before returning (step S228), and if the determination result is NO, the process proceeds directly to step S228 and returns.

[0084] 12(d), first, it is determined whether the judgment operation is "always" (step S231). If the judgment result is YES, the constant processing subroutine is called (step S232) and then the process returns (step S234). If the judgment result is NO, the alarm standby time processing subroutine is called and then the process returns (step S234).

[0085] 13A and 13B are flow charts relating to the determination operation, with FIG. 13A being a flow chart showing the constant processing subroutine and FIG. 13B being a flow chart showing the alarm standby time processing subroutine.

[0086] In the regular processing subroutine shown in FIG. 13(a), first, it is determined whether the action is "promotion" (step S2321). If the result of the determination is YES, the promotion processing subroutine is called (step S2322). 2 ) The process proceeds to step S2324, and if the determination result is NO, the suppression process subroutine is called (step S2323) and the process proceeds to step S2324.

[0087] Next, the determination area notification flag is set to "no" (step S2324), and the process returns (step S2325).

[0088] In the alarm standby time processing subroutine shown in FIG. 13(b), first, it is determined whether or not it is within the alarm standby time (step S2331). If the determination result is YES, the process proceeds directly to step S2326, and if the determination result is NO, the object in the determination area is overwritten with the appearance of an object during alarm standby (step S2332). Furthermore, it is determined whether the action is "promote" (step S2333). 3 3), if the result of the determination is YES, the promotion processing subroutine is called (step S23 3 4) Step S23 3 6, and if the result of the determination is NO, the suppression processing subroutine is called (step S23 3 5) Step S23 3 Go to 6.

[0089] Next, the judgment area notification flag is set to "no" (step S23 3 6), return (step S23 3 7).

[0090] 14A and 14B are flowcharts relating to actions, with FIG. 14A being a flowchart showing the promotion processing subroutine and FIG. 14B being a flowchart showing the inhibition processing subroutine.

[0091] 14(a), first it is determined whether an object is "present" in the alert area (step S23221), and if the determination result is YES it is further determined whether an object is "present" in the determination area (step S23222), and if the determination result is YES the alert area notification flag is set to "present" (step S23223) before returning (step S23225). If the determination result of either step S23221 or step S23222 is NO the alert area notification flag is set to "not present" (step S23224) before returning (step S23225).

[0092] In the suppression processing subroutine shown in FIG. 14(b), first it is determined whether or not an object is "present" in the alert area (step S23231). If the determination result is NO, the process proceeds directly to step S23233. If the determination result is YES, it is further determined whether or not an object is "present" in the determination area (step S23232). If the determination result is YES, the alert area notification flag is set to "no" (step S23233) and the process returns (step S232 3 5) If the determination result in step S23232 is NO, the warning area notification flag is set to "YES" (step S23234), and the process returns (step S23235).

[0093] FIG. 15 is a flowchart showing the alarm output subroutine.

[0094] In the alarm output subroutine shown in FIG. 15, first, it is determined whether the alert area alarm flag is "YES" (step S31), and if the determination result is YES, an alarm output for the alert area is performed (step S3 2 ) The process proceeds to step S33, and if the determination result is NO, the process proceeds directly to step S33.

[0095] Next, it is determined whether or not there is any remaining security area (step S33), and if the result of the determination is YES, the process returns (step S34), whereas if the result of the determination is NO, the process returns to step S31.

[0096] According to the configuration of the first embodiment described above, it is possible to select either the alarm promotion mode or the alarm suppression mode depending on the installation location, the object to be detected, etc., and to perform optimal surveillance by setting appropriate surveillance area B100 and judgment area C100.

[0097] <Second embodiment> In order to improve the target detection performance of the laser scan sensor of the first embodiment described above and suppress false alarms, an image acquired by a built-in camera is also combined, which will be described below as the second embodiment. Note that the same reference symbols are used for the same members as in the first embodiment, and the following mainly describes the differences.

[0098] Fig. 16(a) is a front view of a laser scan sensor 200 according to a second embodiment of the present invention, and Fig. 16(b) is a schematic plan view comparing an imaging range R201 and a laser irradiation range R202 captured by the built-in camera 201. Fig. 17(a) is a schematic view illustrating an image captured by the built-in camera 201 when installed horizontally, and Fig. 17(b) is a schematic plan view illustrating step numbers in the laser irradiation range R202 in Fig. 16(b).

[0099] 16(a), the laser scan sensor 200 has a laser emitting / receiving unit 202 provided at approximately the center of the front surface, and a built-in camera 201 disposed near the upper portion thereof. The built-in camera 201 may be connected to, for example, a unit equivalent to the object detection area notification control unit 145 in the first embodiment.

[0100] As shown in FIG. 16(b), the laser irradiation range R202 is greater than 180 degrees from the front. In order to cover the entire laser irradiation range R202, for example, a fisheye camera may be used as the built-in camera 201, or multiple cameras may be built in and their images may be combined.

[0101] It is necessary to perform calibration in advance so as to understand the positional relationship between each step of the laser irradiation range R202 and each pixel of the imaging range R201. For example, if the laser irradiation line L202 in the image captured by the built-in camera 201 shown in Fig. 17(a) corresponds to step 20 at the right end and step 740 at the left end as shown in Fig. 17(a), for example, a step-pixel table such as the following may be stored in the memory 160.

[0102] Step Pixel 20 1919 21 1918 22 1917 ... FIG. 18(a) is a schematic diagram of a laser scan image when a vertically installed laser scan sensor 200 detects an intruding object, and FIG. 18(b) is a schematic diagram illustrating an image acquired by the built-in camera 201.

[0103] 18(a), within the detection area A200 of the laser scan sensor 200, a first security area B200-1 is formed almost directly below the laser scan sensor 200, and a second security area B200-2 is formed at the edge. The laser scan sensor 200 first detects the moving object 15 through image processing using the built-in camera 201. Since the laser steps and camera pixels are calibrated in advance as described above, it is determined whether the moving object 15 belongs to either of the security areas based on the number of steps of the moving object 15 detected by image processing.

[0104] By allocating the image acquired by the built-in camera 201 as a condition for determining the alert area, it becomes possible to superimpose and determine the object detection by the laser rangefinder 110 and the detection of the moving object by the built-in camera 201, thereby preventing false alarms due to fog, etc. This is because, for example, even thin fog can cause the laser light to be reflected and a non-existent object to be detected, but in such a case, the fog is not detected as a moving object 15 in the image acquired by the built-in camera 201, so false alarms can be avoided.

[0105] <Other embodiments> The laser scan sensor may be a three-dimensional type capable of detecting the height direction. Furthermore, the built-in camera 201 of the second embodiment may be replaced with a stereo camera capable of acquiring three-dimensional images. In this way, it becomes possible to capture the detection target object more accurately and take more appropriate precautions.

[0106] The present invention can be embodied in various other forms without departing from its spirit or main features. Therefore, the above-described embodiments are merely illustrative in all respects and should not be interpreted as being limiting. The scope of the present invention is defined by the claims and is not limited to the text of the specification. Furthermore, all modifications and changes within the scope of the claims are within the scope of the present invention. [Explanation of symbols]

[0107] 11 Thieves and intruders , human body, person 12. Security Guard 15 Objects, moving objects , object to be detected 16 Tracks 17 Passenger cars 20 Entrance / exit 21 Side wall 100 Laser scan sensor (first embodiment) A100 Detection Area B100 Security Area C100 Judgment area 110 Laser Rangefinder 120 Scanning mechanism (scanning mechanism part) 130 Distance data acquisition unit (distance information acquisition unit) 135 Object detection processing unit 140 Object detection area determination unit 145 Object detection area notification control unit 150 Alarm output control unit 160 Memory (information storage unit) 200 Laser scan sensor (second embodiment) 201 Built-in camera (image capture device)

Claims

1. A laser rangefinder that measures the distance to an object by emitting a laser beam and measuring the time it takes for the reflected beam to return from an object in that direction; a scanning mechanism for changing the direction of measurement by the laser range finder; a distance information acquisition unit that periodically performs measurements using the laser distance meter while changing the measurement direction using the scanning mechanism to form a detection area and acquires distance information for each measurement direction within the detection area in time series; an information storage unit that stores reference distance information for each of the measurement directions as detection area information, and stores at least one security area that is set as an area to be actually monitored within the detection area, and a determination area that is set corresponding to each security area; an object detection processing unit that extracts portions that may correspond to a detection target object from the distance information acquired by the distance information acquisition unit, and determines whether or not each of the extracted portions is the detection target object based on a time-series movement status of each of the extracted portions; an object detection area determination unit that determines whether or not the detection target object is present in the security area and the determination area, respectively, or whether or not the detection target object is present in the determination area, based on a determination result of the object detection processing unit; an alarm control unit that controls whether or not to issue an alarm when the detection target object is present within the security area based on the respective determination results of the object detection processing unit and the object detection area determination unit; an alarm output control unit that outputs an alarm signal in response to control by the alarm control unit; A laser scan sensor comprising:

2. 2. The laser scan sensor according to claim 1, The laser scan sensor is characterized in that the alarm control unit controls the sensor to emit an alarm if the detection target object is present within the judgment area when the detection target object is also present within the surveillance area, and controls the sensor to suppress the alarm when the detection target object is not present within the judgment area even if the detection target object is present within the surveillance area.

3. 2. The laser scan sensor according to claim 1, The laser scan sensor is characterized in that the alarm control unit controls the sensor to suppress alarm generation even if the detection target object is present within the surveillance area when the detection target object is present within the judgment area, and controls the sensor to generate an alarm if the detection target object is present within the surveillance area when the detection target object is not present within the judgment area.

4. 2. The laser scan sensor according to claim 1, The information storage unit is capable of storing information on whether the alarm control unit performs control in a first control mode or a second control mode, The alarm control unit is If the first control mode is stored in the information storage unit, When the detection target object is present within the determination area, control is performed so that an alarm is issued if the detection target object is also present within the security area, and when the detection target object is not present within the determination area, control is performed so that an alarm is not issued even if the detection target object is present within the security area, If the second control mode is stored in the information storage unit, A laser scan sensor characterized by being controlled to suppress an alarm even if the detection target object is present in the surveillance area when the detection target object is present within the judgment area, and being controlled to issue an alarm if the detection target object is present in the surveillance area when the detection target object is not present within the judgment area.

5. The laser scan sensor according to any one of claims 1 to 4, The laser scan sensor is characterized in that the alarm control unit continues to indicate that the detection target object exists within the judgment area for a predetermined first specified time even if the detection target object that was present within the judgment area disappears.

6. The laser scan sensor according to any one of claims 1 to 5, The laser scan sensor is characterized in that the alarm control unit waits until the target object is detected within the surveillance area before issuing an alarm for a predetermined second specified time.

7. The laser scan sensor according to any one of claims 2 to 6, Further equipped with a display, The laser scan sensor is characterized in that the alarm output control unit performs control to suppress alarm generation and then displays an indication on the display unit.

8. The laser scan sensor according to any one of claims 1 to 7, The laser scan sensor is characterized in that the alarm output control unit notifies the outside of alarm information for the confirmed alert area.

9. The laser scan sensor according to any one of claims 1 to 8, Furthermore, the device is provided with an operation section that allows the user to select either an external input or the result of image processing as the judgment condition, The laser scan sensor is characterized in that the alarm control unit controls whether or not to issue an alarm based on the presence of the object to be detected in the judgment area that is pre-associated with the judgment condition, depending on the judgment condition being either an external input or an image processing result selected by the operation unit.

10. The laser scan sensor according to any one of claims 1 to 8, Further equipped with an imager, The laser scan sensor is characterized in that the alarm control unit obtains the distance information corresponding to the position of the detection target object in the captured image based on the image processing results of the image captured by the imaging device, and controls whether or not to issue an alarm when the detection target object is present within the surveillance area.

Images