JP2019201268A - Monitoring system and monitoring method - Google Patents

Abstract

To provide a monitoring system that covers an entire area to be monitored, monitors a person or an object approaching a specific object in the area, and warns when a person or an object approaches the specific object.SOLUTION: A monitoring system 100 that monitors the surroundings of a predetermined specific object in a region to be monitored includes a rider 110 that outputs a distance image showing a distribution of a distance value by scanning the region to be monitored, and a control unit 120 that detects the movement of the specific object from within the area, sets an alarm area at a predetermined position such that the specific object is included in the distance image from the rider, and outputs an alarm signal when another object different from the specific object exists in the alarm area.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a monitoring system and a monitoring method.

  One conventional technique for ensuring safety within a predetermined work area is a working robot that performs monitoring work while moving within the predetermined work area. The work robot in this prior art has a three-dimensional map including a predetermined work area and a surrounding data acquisition sensor capable of acquiring three-dimensional shape data around the current location. Then, the work robot moves within the work area, compares the three-dimensional shape data obtained by the surrounding data acquisition sensor with the data of the three-dimensional map, finds a coincidence point between the two data, and on the three-dimensional map. It determines the current position of itself (working robot) during movement.

  In addition, this work robot can detect temperature, radiation, toxic substances, flammable gases, etc. as physical quantities of the current location atmosphere during movement, and if there are places where these physical quantities deviate from the reference value, The location is identified and alerted on the 3D map. When temperature is detected as a physical quantity, a range that is harmless even if touched by humans is set as the reference value range, and when a temperature that is outside the reference value range is detected, it is displayed on the display means. On the three-dimensional map, an alarm is given such as blinking the position where such temperature is detected (Patent Document 1).

Japanese Unexamined Patent Publication No. 2017-102888

  However, in the prior art, a physical quantity cannot be measured at a place where the work robot is not working. The physical quantity is the temperature of the space and the like, and the position of the object itself that causes the temperature to deviate from the reference value cannot be detected. For this reason, even in the predetermined work area, a warning cannot be issued even if the physical quantity of the space exceeds the reference value in a place where the work robot does not perform. Further, it is impossible to detect an object that causes such a cause and movement of such an object.

  Therefore, an object of the present invention is to cover the entire area to be monitored, detect a predetermined object (specific object) in the area, and move the object to approach the surroundings. It is an object of the present invention to provide a monitoring system and a monitoring method capable of monitoring whether or not a person or an object is present.

  The above object is achieved by the following means.

(1) A monitoring system for monitoring the surroundings of a predetermined specific object in an area to be monitored,
A distance image acquisition unit that outputs a distance image showing a distribution of distance values obtained by scanning laser light toward the region;
Detecting the movement of the specific object in the region;
In the distance image acquired from the distance image acquisition unit, an alarm region is set in a predetermined range so as to include the specific object, and another object different from the specific object is detected from the distance image. A control unit that outputs an alarm signal when the detected other object is present in the alarm region;
Having a monitoring system.

(2) a first storage unit that stores in advance the feature amount of the specific object;
When the object is detected from the distance image acquired from the distance image acquisition unit, the control unit obtains a feature amount of the detected object, and stores the detected feature amount of the object and the first storage unit Detecting the specific object by comparing with the feature amount of the specific object,
The monitoring system according to (1), wherein the movement of the specific object is detected from the distance image acquired in time series from the distance image acquisition unit.

(3) A thermal camera that is installed at a position close to the distance image acquisition unit, images the region from substantially the same direction as the distance image acquisition unit, and outputs an infrared image in which the temperature distribution of the region is detected. In addition,
The control unit detects a portion having a predetermined temperature or higher in the infrared image acquired from the thermal camera, and detects an object in the distance image acquired from the distance image acquisition unit in a direction corresponding to the portion. By detecting the specific object,
The monitoring system according to (1), wherein the movement of the specific object is detected from a plurality of the distance images acquired in time series from the distance image acquisition unit.

(4) The control unit detects the position of the specific object moving from the plurality of distance images acquired in time series from the distance image acquisition unit,
The monitoring system according to (2) or (3), wherein the alarm area is moved according to the position of the specific object.

  (5) The monitoring system according to (4), wherein the alarm area set by the control unit is wider in front of the specific object in the movement direction than in front of the specific object in the movement direction.

(6) A second storage unit is further included,
The controller is
The monitoring system according to any one of (1) to (5), wherein the distance image at the time when it is determined that the other object is present in the alarm area is stored in the second storage unit.

(7) A temporary storage unit that temporarily stores the distance image is further included.
The controller is
A plurality of the distance images acquired in time series from the distance image acquisition unit are temporarily stored in the temporary storage unit for a predetermined time,
The past distance image stored in the temporary storage unit until the time when it is determined that the other object is present in the alarm area together with the distance image when it is determined that the other object is present in the alarm area. Is stored in the second storage unit. The monitoring system according to (6) above.

(8) a second storage unit;
A visible light camera that captures the region and outputs a visible light image, or a thermal camera that detects a temperature distribution of the region and outputs an infrared image;
The controller is
The time when it is determined that the other object is present in the alarm area, or the visible light image or the infrared image in a time series for a predetermined time including the time is stored in the second storage unit (1) The monitoring system according to any one of to (5).

(9) Using a monitoring system having a distance image acquisition unit that outputs a distance image showing a distribution of distance values obtained by scanning laser light toward the region to be monitored, A monitoring method for monitoring the surroundings of a predetermined object,
Detecting the movement of the specific object within the region (a);
(B) setting an alarm region in a predetermined range including the specific object in the distance image acquired from the distance image acquisition unit;
Detecting another object different from the specific object from the distance image and alerting when the detected other object is present in the alarm region (c);
Monitoring method.

(10) The monitoring system includes a first storage unit that stores in advance the feature amount of the specific object,
In the step (a), when an object is detected from the distance image acquired from the distance image acquisition unit, a feature amount of the detected object is obtained, and the detected feature amount of the object and the first storage unit Comparing the feature quantity of the specific object stored in (d1) to detect the specific object;
Detecting the movement of the specific object from the distance image acquired in time series from the distance image acquisition unit (d2);
The monitoring method according to (9) above, comprising:

(11) The monitoring system is installed at a position close to the distance image acquisition unit, images the region from substantially the same direction as the distance image acquisition unit, and outputs an infrared image in which the temperature distribution of the region is detected Further having a thermal camera,
In the step (a), a part having a predetermined temperature or higher is detected in an infrared image obtained from the thermal camera, and an object is added to the distance image obtained from the distance image obtaining unit in a direction corresponding to the part. Detecting the specific object by detecting (e1),
The monitoring method according to (9), further including a step (e2) of detecting movement of the specific object from a plurality of the distance images acquired in time series from the distance image acquisition unit.

(12) Detecting the position of the specific object moving from the plurality of distance images acquired in time series from the distance image acquisition unit,
The monitoring method according to (10) or (11), further including a step (f) of moving the alarm area in accordance with the position of the specific object.

  (13) The monitoring method according to (12), wherein the warning area is wider in front of the specific object in the moving direction than in front of the specific object in the moving direction.

(14) The monitoring system includes a second storage unit,
Any of (9) to (13) above, further comprising a step (g) of storing the distance image at the time when it is determined in step (c) that the other object is present in the alarm region in the second storage unit. The monitoring method as described in any one.

(15) The monitoring system includes a temporary storage unit that temporarily stores the distance image,
A step (h) of temporarily storing a plurality of the distance images acquired in time series from the distance image acquiring unit in the temporary storage unit for a predetermined time;
Along with the distance image at the time when it is determined in step (g) that the other object exists in the alarm area, the distance image is stored in the temporary storage unit until the time when it is determined that the other object exists in the alarm area. The monitoring method according to (14), further including a step (i) of storing a past image of the distance in the second storage unit.

(16) The monitoring system includes a second storage unit, a visible light camera that captures the region and outputs a visible light image, or a thermal camera that detects a temperature distribution of the region and outputs an infrared image. In addition,
A step (j) of storing the visible light image or the infrared image in a time series for a predetermined time including the time point when it is determined that the other object exists in the alarm region (j); The monitoring method according to any one of (9) to (13), including:

  According to the present invention, the movement of a specific object that needs to be monitored around the area to be monitored is detected, and the alarm area is set so as to include the specific object. Then, from the distance image obtained by the distance image acquisition unit, it is determined whether or not another object exists in the alarm region, and an alarm signal is issued. For this reason, the entire monitored area can be monitored at once, and if there is a specific object that may cause danger in the surrounding area, an alarm will occur if another object such as a person enters the surrounding alarm area. Can be issued.

It is a block diagram which shows the structure of the monitoring system of Embodiment 1. 6 is a flowchart illustrating a processing procedure of a monitoring operation according to the first embodiment. It is a schematic diagram overlooking the whole monitoring field for explaining an example of a warning field. It is a schematic diagram overlooking the whole monitoring field for explaining other examples of a warning field. It is a screen example figure which shows the example of a display after alarm area | region setting. It is the schematic which overlooks the whole monitoring area | region for demonstrating the condition where the other object entered into the warning area | region. It is a block diagram which shows the structure of the monitoring system of Embodiment 2. FIG. 6 is a schematic view overlooking the entire monitoring area for explaining the configuration of the monitoring system of the second embodiment. 10 is a flowchart illustrating a processing procedure of a monitoring operation according to the second embodiment. It is a flowchart which shows the process sequence of the monitoring operation | movement of Embodiment 2 following FIG. It is a figure which shows the infrared image example by the thermal camera of Embodiment 2. FIG. It is a figure which shows the example of a distance image by the rider of Embodiment 2. FIG. It is a block diagram which shows the structure of the monitoring system at the time of installing the movie camera which image | photographs an object with visible light as a modification.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The present invention is not limited to the following embodiments. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. Since the drawings are created for the purpose of facilitating understanding of the present invention, the drawings are exaggerated and the dimensional ratios of the drawings may be different from the actual dimensional ratios.

(Embodiment 1)
FIG. 1 is a block diagram illustrating a configuration of a monitoring system according to the first embodiment.

  The monitoring system 100 includes a rider 110, a control unit 120, a display 130, and an alarm device 140. The rider 110 scans the entire area to be monitored, and detects an object in the area (for example, a specific object for monitoring the surroundings, other objects different from a specific object such as a person, a vehicle, and other objects). It is installed at a position where it can be captured.

  A rider 110 (LiDAR: Light Detection And Ranging) scans a laser beam toward a space of a region to be monitored and measures a distance from the reflected light to an object existing in the scanned space. The obtained distribution of distance values is also referred to as point cloud data, and the distance from the installation position of the rider 110 to the object, and the size and shape of the object are known. When the rider 110 scans the laser beam for one frame, an image having a distance value distribution that is a distance to an object existing in the space or an infinite distance when there is no reflected light is obtained. Such a distance value output from the rider 110 becomes a distance image for one frame (sometimes referred to as a rider image). The rider 110 alone may function as a distance image acquisition unit, and the distance image may be created from the distance value to the object obtained by the rider 110 scanning himself and the distance image may be output from the rider 110. Further, the rider 110 and the control unit 120 may function as a distance image acquisition unit. In this case, distance value data is output from the rider 110, and the control unit 120 that has received the distance value creates a distance image. Such a distance image is created as an image of a three-dimensional coordinate system.

  In the present embodiment, hereinafter, a description will be given as a mode in which the rider 110 creates a distance image from the distance value and outputs it to the control unit 120. Of course, in the processing procedure described later, the same processing is performed when the control unit 120 acquires a distance value from the rider 110 and creates a distance image from the distance value.

  The rider 110 uses an infrared laser. The laser beam used for the rider 110 preferably uses a wavelength of 800 to 1000 nm when monitoring a work place that carries hot metal described later. In the case of a high-temperature object such as hot metal, infrared rays are emitted even if it is put in a hot metal pan (ladle) (the hot metal pan is open). For this reason, if the infrared wavelength emitted by such a high-temperature object and the wavelength of the laser beam used by the rider are covered, there is a possibility of erroneous detection. Incidentally, the temperature of the hot metal is about 1200 to 1500 ° C., and the temperature of the outer wall of the hot metal ladle containing the hot metal is about 250 ° C. And the peak wavelength of the black body radiation energy in 1000-1500 degreeC (1273-1773K) is 2278-1636nm. Therefore, by using laser light having a wavelength of 800 to 1000 nm, the visible light wavelength is not used, and the peak wavelength of the radiant energy from the high-temperature object is not fogged, so that erroneous detection can be prevented. Of course, the wavelength of the laser beam used by the rider 110 may be set according to the wavelength of the radiant energy of the specific object.

  The rider 110 has a scanning interval of about 10 frames / second, for example. This scanning interval may be set arbitrarily.

  A moving image is formed by arranging a plurality of distance images (frames) in time series.

  The control unit 120 is a computer. The control unit 120 includes a CPU (Central Processing Unit) 121, a ROM (Read Only Memory) 122, a RAM (Random Access Memory) 123, a HDD (Hard Disk Drive) 124, and the like. The CPU 121 calls a program corresponding to the processing content from the HDD 124 to control the operation of the rider 110, and performs detection of the three-dimensional position of the object, temperature of the object, alarm operation, display of temperature information, and the like. The HDD 124 becomes a storage unit together with the RAM 123, and stores programs and data necessary for each processing. Although the HDD 124 is used in FIG. 1, a nonvolatile semiconductor memory such as a flash memory may be used instead of the HDD 124.

  The control unit 120 includes an input device 125 such as a touch panel, buttons, and a mouse, and a network interface 126 (NIF: Network Interface) for connecting an external device such as a server.

  The display 130 displays a distance image and other information according to an image signal from the control unit 120. In the present embodiment, the display 130 can be provided separately from the control unit 120 in order to install the display 130 in a factory monitoring room, for example. The control unit 120 may be integrated. Further, the display 130 and the alarm device 140 may be integrated depending on the monitoring environment.

  The alarm device 140 issues an alarm by, for example, sound, light such as a flashlight or a rotating light, and other methods that can be recognized by a person. Instead of the alarm device 140, other processing may be performed. Other processing includes stopping automatic machines such as robots, machine tools, and transport vehicles.

  The control unit 120 may use a general-purpose computer instead of a dedicated computer. Further, the rider 110 and the control unit 120 may be integrated. In addition, the control unit 120 is shown as a form mainly composed of a CPU, a RAM, and a ROM. However, the control unit 120 is configured by an integrated circuit such as an FPGA (Field-Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit). Also good.

  The operation of the monitoring system 100 will be described. FIG. 2 is a flowchart showing the processing procedure of the monitoring operation by the control unit 120. In the following description, the current frame refers to a frame acquired at the current time point, and the previous frame refers to a frame immediately before the current frame in time series. Since this procedure includes repetitive processing, for convenience of explanation, processing using the result of processing at a later stage may be described first.

  First, the control unit 120 acquires a distance image for one frame at the current time point from the rider 110 (S11). The distance image acquired here is temporarily stored in the RAM 123 or HDD 124 for a predetermined time. The temporarily stored distance images may be deleted in the order in which a predetermined time has elapsed, or may be deleted in order from the oldest when the storage capacity is insufficient. Temporary storage time is a few seconds, for example. Any number of minutes, hours, days, weeks, months, etc. may be arbitrarily determined in consideration of the capacity and necessity of the storage device. The storage destination may be possible in the RAM 123 for a few seconds to a few minutes, but if it is stored for a longer time, it may be a large-capacity memory such as the HDD 124 even for temporary storage. Thus, the RAM 123 or the HDD 124 that temporarily stores past distance images serves as a temporary storage unit.

  Subsequently, the control unit 120 uses the background difference method to detect and cluster objects detected in the distance image (S12). As is well known, the background subtraction method compares an image registered in advance as a background image with the acquired frame image (here, the distance image of the frame acquired in S11), and if there is a different part from the background image. The portion is detected as a newly appearing object. The background image is, for example, a distance image obtained by scanning without an object in an area scanned by the rider 110. Such a background image is stored in, for example, the HDD 124 and read out to the RAM 123 for use.

  Clustering is for tracking the detected object in subsequent processing, and a known method can be used. In the clustering, for example, a cluster value may be formed as a cluster using the distance value from the three-dimensional coordinate system set in the distance image to the detected object as a feature amount. Further, a cluster of objects may be formed from the coordinate values in the three-dimensional coordinate system as feature quantities such as the size of the object (the length or area of the object in the X, Y, and Z axis directions in the three-dimensional coordinate system). In addition, together with these feature amounts, for example, the cluster center coordinate value and the cluster outline coordinate value are temporarily stored in the RAM 123 as the cluster position. The position of the temporarily stored object (coordinate value of the cluster) is temporarily stored for a predetermined time like the distance image. The three-dimensional coordinate system set for the distance image will be described later (FIG. 5).

  Subsequently, the control unit 120 performs moving body tracking for the clustered object (S13). In the moving object tracking, it is searched whether or not an object of the same cluster as the object clustered in the distance image of the current frame was in the previous frame. If there is an object of the same cluster in the previous frame, the position of the previous frame of the object (the position is a coordinate value, the same applies below) is compared with the position of the current frame, and the moving distance along with the current position of the object. Find the direction of travel and speed (speed is obtained by dividing distance by time between frames). Thereby, the position, moving distance, moving direction, and speed are temporarily stored in the RAM 123 for each object. Since the temporary storage here is used to calculate the position, moving distance, moving direction, and speed for each object, it is preferable to store at least one past frame in the RAM 123 that is a memory capable of high-speed operation.

  In S13, if there is an object that does not exist in the previous frame but is detected in the current frame, the object is stored in the RAM 123 as an object that has appeared in the current frame.

  Although processing using the moving distance, moving direction, and speed of the object will be described later, if these are not used, only the coordinate value (position) of the three-dimensional coordinate system of the object in the current frame may be obtained together with clustering.

  Further, for example, a frame fb (see FIG. 5) or a mark surrounding the object may be attached to the object detected as a moving object in S13 and displayed on the display 130. This makes it easier to understand the object displayed on the display.

  Subsequently, the control unit 120 determines whether or not the object detected in S12 is a specific object (S14). The specific object is an object in which it is dangerous that a person or another object approaches the object. For example, it is an object larger than a person like a hot metal ladle described later. If an object larger than a person moves, there is a danger of a collision. The hot metal pan is a hot object. For this reason, approaching the surroundings is also a dangerous object.

  In determining whether or not the object is a specific object, the feature amount of the specific object is stored in the RAM 123 in advance, and compared with the detected feature amount of the object, it is determined whether or not they are the same. The feature quantity of the specific object stored in advance is the feature quantity of the cluster as described above. For example, the number of pixels of the detected object (distance value), the size obtained from the coordinate value of the object in the three-dimensional coordinate system, etc. It is. The feature quantity of the specific object is stored in advance in the HDD 124, and is read out to the RAM 123 and used when the process is started. For this reason, the HDD 124 is a first storage unit. Note that the first storage unit is not in the control unit 120, but uses, for example, a storage device such as a server connected to the control unit 120 via a network (which may be wired or wireless) or another computer installed in the management department. May be. In such a case, the feature quantity of the specific object is read from the storage device to the RAM 123 and used together with the start of the monitoring operation process. In this case, a storage device such as a server or another computer connected to the control unit 120 becomes the first storage unit and is a part of the monitoring system.

  If there is no specific object (S14: NO), the process returns to S11. Although not shown in detail, if no object is detected in S12, S14 is NO as a matter of course, so that the process returns to S11. If NO is determined in S14, if there is data indicating that an alarm area described later is set, the data is cleared to indicate that the alarm area is not set (this is described later in S15). Is required for processing).

  If the control unit 120 detects a specific object (S14: YES), then the control unit 120 determines whether or not an alarm area already exists (S15). The presence / absence of the alarm area is determined by checking data indicating that the alarm area has been set, which is stored when the alarm area is set in S16 described later. If the warning area has already been set, the process proceeds to S20. The process of S20 will be described later.

  In S15, if there is no alarm area (S15: NO), then the control unit 120 sets an alarm area around the specific object (S16).

  The absence of an alarm area in S15 means that the object has been detected as a specific object for the first time at S14. This also means an object that has appeared in the stage of S13 from the processing flow of the present embodiment. Therefore, such a specific object is that the specific object originally in the region has moved and detected a difference from the background image, or that the specific object has moved from outside the region into the region. . For this reason, in any case, the movement of the specific object is detected in the region.

  Here, a specific example is given and demonstrated about an alarm area | region. FIG. 3 is a schematic view overlooking the entire monitoring area for explaining an example of the alarm area.

  The example of FIG. 3 is a work area in the ironworks, and is a site where hot metal (molten iron) is taken out from the blast furnace to the hot metal ladle 300 and conveyed to the converter. In this work area, the hot metal ladle 300 containing hot hot metal moves. As is well known, the hot metal ladle 300 is formed of refractory bricks. For this reason, the outside of the hot metal ladle 300 is approximately 200 to 300 ° C. Until now, during the movement of the hot metal ladle 300, rules have been made to ensure safety by preventing people from entering the predetermined range in and around the movement path of the hot metal ladle 300. However, when the hot metal ladle 300 is not moving, since it is necessary for a person to enter and exit the moving path of the hot metal ladle 300 for cleaning and other work, a fence or the like surrounding the moving path is not provided. For this reason, a person may approach the hot metal ladle 300 during movement.

  In FIG. 3, the rider 110 is installed at a position where the entire moving path (entire monitoring area) of the hot metal ladle 300 can be scanned. And the control part 120 has memorize | stored the feature-value of the hot metal ladle 300 in RAM123, in order to detect the hot metal ladle 300 as a specific object. The feature amount of the hot metal ladle 300 is, for example, scanned by the rider 110 in a state where the hot metal pan 300 exists in the monitoring area and there is no other object, and the detected object is rasterized to obtain the feature amount. Extract. Since the extracted feature value becomes the feature value of the hot metal ladle 300, it is stored in the HDD 124 as the feature value of the specific object. Then, at the start of processing (at the start of this processing procedure), the data is read out to the RAM 123 and used to detect a specific object in S14 described above.

  In the example of FIG. 3, the alarm region 500 is set in a range that includes the moving path 301 of the hot metal ladle 300. The range in which the alarm area 500 is set is determined in advance, and here is a range in which the moving path 301 of the hot metal ladle 300 is included. For example, the moving path 301 along which the hot metal ladle 300 moves while being caught by a crane is also determined in advance, and the moving path 301 does not change variously. Of course, when the movement route 301 is changed, the setting range of the alarm area 500 is also changed accordingly.

  The alarm area 500 is three-dimensionally set within a predetermined distance from the hot metal ladle 300 in the three-dimensional coordinate system of the range scanned by the rider 110. In the case of the hot metal ladle 300, the predetermined distance is at least a range in which the hot metal ladle 300 is damaged by the radiant heat. In addition to the movement path 301 being set above, both sides of the movement path 301 and the hot metal ladle 300 are set so as to include the lower part of the hot metal ladle 300 in the case of air transportation by a crane or an upper rail. The predetermined distance may be a length having a further margin from the range of harm.

  Further, another example of the alarm area will be described. FIG. 4 is a schematic view overlooking the entire monitoring area for explaining another example of the alarm area.

  In the example of FIG. 4, the range of the alarm area is changed in accordance with the movement of the hot metal ladle 300.

  The moving direction of the hot metal ladle 300 is determined in the moving object tracking process of S13. In the example of FIG. 4, the area of the alarm region 501 to be set is widened forward in the moving direction of the hot metal ladle 300 (a predetermined distance is longer in the forward direction of movement), and the rear of the hot metal ladle 300 in the moving direction is narrower than the front ( The predetermined distance is short. And the alarm area | region 501 is moved according to the movement of the hot metal ladle 300 (refer S20 mentioned later). FIG. 4A shows the position of the hot metal ladle 300 at a certain time t1 and an alarm area 501 corresponding to the position. FIG. 4B shows the position of the hot metal ladle 300 at the time t2 when the time has elapsed and the alarm region 501 corresponding to the position. In this way, since a wider range is set in front of the hot metal ladle 300 in the moving direction, if a person is in that direction, the hot metal ladle 300 will approach, so an alarm can be issued quickly. it can. On the other hand, at the rear of the hot metal ladle 300 in the moving direction, there is little risk even if the predetermined distance is shortened. For this reason, the operation | movement in the moving path | route of the hot metal ladle 300 and its periphery can enter the operation | work safely and earlier. In this case, it is preferable that the predetermined distance in the rear of the hot metal ladle 300 in the moving direction is within a range that is not affected by the radiant heat of the hot metal ladle 300. It is preferable to make the predetermined distance further longer than the range where the harm caused by.

  In the example of FIG. 4, the position where the alarm area 501 is set may be determined in advance according to the movement path of the hot metal ladle 300, and the alarm area 501 may be moved according to the movement of the hot metal ladle 300. However, the present invention is not limited to this, and the present invention can also be applied when the moving path of the hot metal ladle 300 is not set in advance. When the moving path of the hot metal ladle 300 is not set in advance, the range of the alarm area 501 is set as a first predetermined distance forward from the hot metal ladle 300 in the moving direction and a second predetermined distance backward in the moving direction (in the RAM 123). Remember). Then, the alarm area 501 may be moved in accordance with the position of the specific object obtained by moving body tracking in S13 (see S20 described later).

  FIG. 5 is a screen example showing a display example after the alarm area is set. This screen is based on the distance image acquired in S11. This screen is a three-dimensional image with the installation position of the rider 110 as the origin (0 m). The depth is the Z axis direction, the main scanning direction orthogonal to the Z axis is the X axis, and the sub scanning direction orthogonal to the Z axis and the X axis is the Y axis.

  In this screen, a person exists as a plurality of other objects ob1 to ob3. For these other objects ob1 to ob3, a frame line fb is attached so as to be easily understood on the screen. Also, there is a hot metal ladle 300 (specific object), and an alarm area 500 set around it is displayed. In FIG. 5, the alarm area 500 according to the example of FIG. 3 described above is used, but the alarm area 501 of the example of FIG.

  Returning to the flowchart, the description will be continued. After setting the alarm area, the control unit 120 determines whether another object (such as a person or an object) that is different from the specific object is in the alarm area (S17). This comparison compares the range surrounded by the coordinate value of the outer shape of the cluster and the coordinate value indicating the warning area of the object clustered in S12 (that is, the object detected by the background difference method). If the coordinate value of the outer shape of the cluster of another object is within the alarm area, it is determined that the other object is within the alarm area.

  Here, if it is not determined that another object is in the alarm region (S17: NO), the process returns to S11, each image of the next frame is acquired, and the subsequent processing is continued.

  On the other hand, if it is determined that another object is in the alarm area (S17: YES), the control unit 120 outputs an alarm signal to the alarm device 140 (S18).

  FIG. 6 is a schematic view overlooking the entire monitoring area for explaining a situation where another object enters the alarm area.

  As shown in FIG. 6, the person 600 as another object has entered the alarm area 500. In such a situation, an alarm signal is output from the control unit 120 in S18. Thereby, an alarm sound is emitted from the alarm device 140 that has received the alarm signal. At this time, the display 130 blinks an object (or a frame or mark surrounding the object) that is determined to be within the alarm area, changes the color of the entire screen, blinks, or even a warning message. Is displayed. It can be seen from these that the alarm is also issued visually. Along with the alarm device 140, various alarm operations such as turning on the rotating lamp, changing the color of the color-coded layered display lamp from blue to red, and turning on and blinking other lamps, etc. You may go. Moreover, from the alarm device 140, not only an alarm sound but also an audio warning broadcast may be played. Further, the alarm device 140 is not limited to the diffusion alarm directed to the work area. For example, when the worker wears a wireless terminal or the like, an alarm sound or a warning may be output from the wireless terminal. In this case, the wireless terminal equipped by the worker is an alarm device. Furthermore, the alarm signal may be transmitted together with the output to stop the movement of the hot metal ladle 300 in the above-described example, or may be transmitted to a management department that manages the work place.

  Further, when it is determined in S17 that another object is in the alarm area, a distance image that has been temporarily stored from that time is read from the RAM 123 (or HDD 124) (in addition to reading the data itself, Including identifying or tagging the relevant data without reading the data itself). Then, the read data (or specified data, etc.) is re-stored in the HDD 124 with a tag indicating that there is another object that has entered the alarm area. When the past distance image is temporarily stored in the HDD 124, the storage area may be changed in the HDD 124, and the tagged data may not be erased even after a certain period of time. Good. Alternatively, the data may be transferred to a server or a management device. In this case, a storage device such as a server or another computer connected to the control unit 120 is a part of the monitoring system. A storage device (HDD 124 or other storage device) that changes the past distance image from temporary storage to permanent (nonvolatile) storage and stores it becomes the second storage unit (permanent storage is Here, unlike the above-mentioned temporary storage, it means that it will not be erased even if a certain period of time comes).

  As described above, when there is an object that has entered the alarm area, the intrusion route can be known by storing the distance image from before entering the alarm area together with the distance image at that time. Such an intrusion route can also be used, for example, for risk risk evaluation and analysis.

  Thereafter, the process returns to S11 and the processing is continued. When the specific object disappears after returning from S18 to S11 (S15: NO), or when another object comes out of the alarm area (S18: NO), an alarm signal is output. You may make it stop. Further, after the alarm signal is output, for example, the alarm may continue to sound unless the alarm is manually turned off.

  The process of S20 will be described. In S20, the alarm area is already set up to the previous frame. In addition, moving object tracking (S13) is also performed in the current frame acquired at that time. For this reason, if the specific object is a moving object, its moving distance, direction, and speed are known. Therefore, in S20, the control unit 120 moves the alarm area in accordance with the position of the specific object as in the above-described example of FIG. For this, the coordinate value of the alarm area set up to the previous frame is moved in accordance with the movement of the coordinate value of the current position of the specific object. As a result, if the alarm area has already been set up to the previous frame, it is only necessary to move the alarm area in accordance with the movement of the specific object, so the calculation is easier than setting the alarm area each time it is moved. (The processing speed can be increased). If the alarm area is fixed as in the example of FIG. 3, the process of S20 is not performed, and if S15: YES, the process proceeds directly to S17.

  As described above, the monitoring operation is executed as a repetitive process.

  According to Embodiment 1 demonstrated above, there exist the following effects.

  According to the first embodiment, a specific object is detected by comparing a predetermined feature amount of a specific object with a feature amount of the detected object from objects detected from the distance image of the rider. The movement of the specific object is detected by tracking the moving object from a plurality of distance images arranged in time series. If the movement of the specific object is detected, an alarm area is set in a predetermined range including the specific object. Thereafter, if there is another object different from the specific object in the alarm area in the acquired distance image, an alarm is issued. As a result, other objects approaching the specific object can be reliably detected and alarmed. For example, when the specific object is a saddle object larger than a person, the possibility of a collision between the large object and the person can be warned. When the specific object is a high-temperature object, an alarm can be given that a person has approached the high-temperature object. In particular, in the present embodiment, since the movement of a specific object is detected, the specific object approaches not only the case where the specific object approaches another object such as a person but also the other object such as a person. An alarm can be issued when going.

  In addition, by setting an alarm region, it is not necessary to calculate the distance between the specific object and another object every time a distance image is acquired, so the processing can be speeded up.

  Further, by moving the alarm area according to the position of the moving specific object, the alarm area can be minimized and the work area can be secured as much as possible.

  Further, when setting the alarm region, the predetermined distance is set so that the front of the specific object in the moving direction is wider than the rear (longer in the forward direction). As a result, a warning is issued as soon as possible in a range where the specific object is approaching, and safety is ensured in a range where the specific object is moving away, and work can be started quickly.

  Further, when it is determined that there is another object that has entered the alarm area, a past distance image is stored with a tag indicating that. Thereby, since an intrusion route can be understood, it can be used for, for example, evaluation and analysis of danger risks.

  The specific object is detected by comparing the feature amount of the specific object stored in advance in the RAM 123 or the like with the feature amount of the object detected from the distance image acquired at the present time. For this reason, since it is not necessary to use another sensor for the detection of a specific object, apparatus cost can be reduced.

  Further, an object is detected from the distance image of the rider 110, and monitoring is performed so that an alarm can be issued as a specific object based on the feature amount. For this reason, for example, it is possible to give an alarm even when the object itself may pose a danger to the surroundings as compared to the case of detecting the environment and surrounding physical quantities as in the prior art. For example, in the case of an object that is larger than a person and does not change in the physical quantity around the object, the prior art cannot detect the danger. In the first embodiment, even in such a case, it can be detected as a specific object, and an alarm can be issued when another object different from the specific object such as a person or another object approaches the surrounding area.

(Embodiment 2)
In the first embodiment described above, a specific object is identified by comparing the feature quantity of the specific object stored in advance with the feature quantity of the object detected from the rider's distance image, and its movement is detected. Instead, in the second embodiment, a high-temperature object is detected as a specific object using a thermal camera.

  FIG. 7 is a block diagram illustrating a configuration of the monitoring system according to the second embodiment. FIG. 8 is a schematic view overlooking the entire monitoring area for explaining the configuration of the monitoring system of the second embodiment.

  In the second embodiment, as shown in FIG. 7, a thermal camera 210 (infrared camera) is further provided in the monitoring system of the first embodiment.

  As is well known, the thermal camera 210 senses infrared rays emitted from an object in the imaging area and obtains an infrared image composed of a temperature distribution in the imaging area.

  Since the configuration other than the thermal camera 210 and the monitoring operation (processing procedure) after detecting a specific object are the same as those in the first embodiment, the description thereof is omitted. In the second embodiment, detection of a specific object using the thermal camera 210 will be mainly described below.

  The thermal camera 210 is installed close to the rider 110 as shown in FIG. At this time, the direction in which the image is taken by the thermal camera 210 and the direction in which the rider 110 scans are substantially the same. For this purpose, it is preferable to arrange the thermal camera 210 and the rider 110 as close as possible, for example, within 50 cm. Of course, the thermal camera 210 and the rider 110 may be arranged so as to be in contact with each other, or they may be integrated in one case.

  A specific object detection operation using the thermal camera 210 and the rider 110 arranged as described above will be described. 9 and 10 are flowcharts illustrating the processing procedure of the monitoring operation according to the second embodiment. FIG. 11 is a diagram illustrating an example of an infrared image by the thermal camera according to the second embodiment. FIG. 12 is a diagram illustrating an example of a distance image by the rider according to the second embodiment. The infrared image in FIG. 11 and the distance image in FIG. 12 are adjusted so that the sizes (image sizes) of the images are substantially the same.

  First, the control unit 120 acquires an infrared image obtained from the thermal camera 210 (S201), and determines whether or not there is a portion having a predetermined temperature or more (S202). Here, as shown in FIG. 11, if there is a portion 400 of a predetermined temperature or higher in the infrared image, it is detected. The part 400 above the predetermined temperature detected here is, for example, a hot metal ladle (a ladle) as in the first embodiment. On the other hand, if there is no portion above the predetermined temperature (S202: NO), the process returns to S201.

  If the portion 400 having a predetermined temperature or more is detected from the infrared ray image (S202: YES), the control unit 120 subsequently acquires a distance image of the rider 110 (S203) and determines whether there is an object (S203). S204). Here, as shown in FIG. 12, if there is an object 450, it will be detected. The detection of the object from the distance image is performed by the background difference method as in the first embodiment. On the other hand, if no object is detected (S204: NO), the process returns to S201.

  Note that either of S201 and S202 and S203 and S204 may be performed first as a procedure (may be performed simultaneously).

  If the object 450 is detected from the distance image (S204: YES), the control unit 120 compares the direction of the portion 400 above the predetermined temperature with the direction of the object 450, and compares the portion 400 above the predetermined temperature with the object 450. Are in the same direction (S205).

  The direction of the part 400 above the predetermined temperature is stored in the RAM 123 by specifying the direction where the part 400 above the predetermined temperature is located from the origin in the infrared image with the installation position of the thermal camera 210 as the origin. Similarly, the direction of the object 450 is determined by specifying the direction in which the object 450 is located from the origin in the distance image with the installation position of the rider 110 as the origin, and is stored in the RAM 123. Then, the respective directions are compared.

  Specifically, these directions are specified as positions in the infrared image and the distance image. The direction of the portion 400 above the predetermined temperature can be expressed as a coordinate value in the infrared image. For example, a two-dimensional coordinate system in which the horizontal direction is the X axis and the vertical direction is the Y axis is set in the infrared image, and the coordinate value of the portion 400 of the predetermined temperature or higher is obtained. Further, the direction of the object 450 is obtained as a coordinate value of the three-dimensional coordinate system of the distance image. The three-dimensional coordinate system in the distance image is the same as that in the first embodiment.

  The thermal camera 210 and the rider 110 are photographed and scanned from the same direction. For this reason, the two-dimensional coordinate system in which the XY plane is extracted from the three-dimensional coordinate system in the distance image and the two-dimensional coordinate system in the infrared image have substantially the same angle of view. Therefore, when the positions (coordinate values) of these two-dimensional coordinate systems are compared, if the portion 400 above the predetermined temperature and the object 450 are the same, the position (coordinate values) of the portion 400 above the predetermined temperature and the position of the object 450 The (coordinate values) are almost the same position. The substantially the same position means that the portion 400 above the predetermined temperature and the object 450 have a certain size (number of pixels), and therefore, the overlap of these pixels is assumed to be 50% or more. Of course, it may be the same if 1% overlaps even if it is not 50%, or conversely, it may be determined that the overlap is 60% or more. However, in such image comparison, since the resolution (number of pixels) of the infrared image and the resolution (number of pixels) of the distance image are different, the two-dimensional coordinate systems are adjusted to have the same scale. Compare.

  Note that the determination of these directions is not determined from the coordinate values of the orthogonal coordinate system, but may be determined from, for example, an infrared image and a distance image in which a polar coordinate system is set. In the polar coordinate system, if the installation positions of the thermal camera 210 and the rider 110 are set as the origin, the direction of the portion 400 and the object 450 at a predetermined temperature or higher is obtained as an angle from the origin in each polar coordinate system. These angles are the same as long as they are within a certain range of angles.

  If the direction of the part 400 and the object 450 at the predetermined temperature or higher is not the same (S205: NO), the control unit 120 returns to S201 and continues the process.

  On the other hand, if these directions are the same (S205: YES), the control unit 120 determines that the object 450 detected from the distance image of the rider 110 is a specific object (here, hot metal ladle), and therefore clusters the specific object. (S206). Clustering can be performed in the same manner as in the first embodiment. Thereby, it can be seen that the object 450 detected from the distance image of the rider 110 is a high-temperature object having a predetermined temperature or higher.

  Subsequently, the control unit 120 acquires a distance image (S211) and performs tracking of moving objects of the clustered specific object (S212). Similarly to the first embodiment, the moving body tracking is performed from the distance image acquired in time series from the rider 110 after clustering.

  Subsequently, if the specific object does not exist as a result of tracking the moving object of the specific object (S213: NO), the process returns to S201. This is a case where the moving specific object reaches the end point or goes out of the scanning area. If the specific object no longer exists, the alert area is canceled as in the first embodiment.

  On the other hand, if the specific object exists (S213: YES), thereafter, the processing is continued as in the first embodiment (S15 to S20). That is, if the specific object has moved and the warning area 500 has already been set (S15: YES), the warning area 500 is moved (S20). If the movement of the specific object is detected and the alarm area 500 is not set (S15: NO), that is, if the movement of the specific object is detected, the alarm area 500 is set around the specific object (S16). Thereafter, intrusion detection (S17, S18) of another object is performed.

  Also in the second embodiment, the warning area may be set so as to include the entire movement route 301 when the movement route is known in advance.

  Such detection of a specific object using the thermal camera 210 is particularly effective when, for example, detecting a movement of a high-temperature object and issuing an alarm.

  An example of the hot object is a hot metal pan. When detecting a hot metal ladle as a specific object, for example, if a predetermined temperature is set to 70 ° C. and a portion of 70 ° C. or higher is in the infrared image, it is detected as a portion of a predetermined temperature or higher. Then, the direction and size are set as the feature amount. Of course, the predetermined temperature is not limited to 70 ° C., and may be set any number of times. For example, the temperature is set so as to harm people and things. In the field where high temperature protective clothing is worn, the temperature may be about 70 to 200 ° C. On the other hand, in a work place with plain clothes that does not have a protection function against high temperatures, the temperature may be about 40 to 70 ° C.

  The reason for confirming whether or not the portion of the infrared image that is equal to or higher than the predetermined temperature is the same as the object in the distance image will be described.

  The hot metal ladle illustrated as the specific object in the second embodiment has a blast furnace and a converter near its moving range. If there are these blast furnaces and converters in the imaging range of the thermal camera 210, they will be detected as being at a predetermined temperature or higher if their lids are open. On the other hand, from the distance image of the rider 110, since the blast furnace and the converter are stationary objects, they are not detected by the background subtraction method (because the stationary object becomes the background when the background image is registered). However, objects that are not hot, such as heavy machinery and vehicles, may enter the work site. Then, a heavy machine or a vehicle is detected as an object from the distance image of the rider 110.

  Here, when a blast furnace, a converter, or the like is detected as a portion having a predetermined temperature or more in the infrared image, a heavy machine or a vehicle may be detected as an object in the distance image at the same time. These parts and objects are not the same. In such a case, simply recognizing a part that is equal to or higher than a predetermined temperature and an object is erroneous recognition.

  In the second embodiment, it is determined whether or not they are the same by comparing the direction of the portion above the predetermined temperature with the direction of the object. For this reason, when a part having a predetermined temperature or higher due to heat radiation from a stationary object and a low-temperature object are detected at the same time, erroneous recognition that they are the same is prevented. In addition, even when there are a plurality of moving high-temperature objects that are equal to or higher than the predetermined temperature, it is possible to individually recognize them as specific objects by comparing in this way.

  In order to determine whether or not the portion detected by the thermal camera 210 is equal to or higher than the predetermined temperature and the object detected by the rider 110 are the same, the sizes may be compared in accordance with these directions. For example, the photographing area 210a of the thermal camera 210 and the scanning area 110a of the rider 110 are set to have substantially the same size. This can be adjusted by adjusting the focal length of the lens of the thermal camera 210 so that the angle of view is the same as the XY plane of the distance image. As a result, the size of the object on the XY plane in the distance image and the portion of the infrared image captured by the thermal camera 210 in the infrared image is approximately the same size. In this case, the position in the image comes to the same position as already described. As a result, it is possible to determine the identity between a part having a predetermined temperature or more and an object not only from the direction but also from the size.

  As described above, the second embodiment has the following effects in addition to the effects of the first embodiment described above.

  When a part having a predetermined temperature or higher is detected in the monitoring area by the thermal camera 210, the direction of the part is compared with the direction of the object detected from the distance image of the rider 110 to detect a specific object. If a specific object exists and moves, an alarm area is set around it. Thus, an alarm can be issued when a specific object having a predetermined temperature or higher approaches another object such as a person or an object.

  In the second embodiment, as in the first embodiment, an infrared image (or an infrared image alone) may be temporarily stored together with a distance image at regular time intervals. If it is determined that there is another object that has entered the alarm area, an infrared image (or an infrared image alone) is stored together with a past distance image with a tag indicating that. As a result, another object that has entered a warning area provided around a specific object (for example, a high-temperature object) can be viewed as a temperature distribution image by an infrared image.

(Modification)
Furthermore, an example in which a normal movie camera (visible light camera) that captures an object with visible light and outputs a visible light image will be described as a modification of the first or second embodiment.

  FIG. 13 is a block diagram illustrating a configuration of a monitoring system when a movie camera that captures an object with visible light is installed as a modification.

  In this modification, a normal movie camera (simply referred to as a camera 310) that captures an object with visible light is installed at a position where a region to be monitored can be captured.

  Then, the inside of the monitoring area is photographed and temporarily stored for a predetermined time (so-called loop recording). After that, when another object enters the alarm area by the processing of the first or second embodiment, the video (moving image) recorded in the loop recording is stored again in another storage device, or the portion of the loop recording is recorded. Or erasure is prohibited. In addition, it is set as the memory | storage to a 2nd memory | storage part including making a loop video recording permanent (it does not delete). In this way, when not only distance images and infrared images but also other objects that are different from a specific object such as a person or object invading normal images, they can be used for observation and analysis of the intrusion process of other objects. Can do. For recording by the camera 310, for example, the HDD 124 or a server can be used as the second storage unit.

  The second storage unit may be other than the control unit 12. For example, a video recording device (not shown) that stores video from the camera 310 exclusively may be provided. This recording device serves as a temporary storage unit and a second storage unit. In this recording device, the video from the camera 310 is always recorded in a loop (becomes a temporary storage unit). Then, when the control unit 120 detects that another object has entered the alarm area by the processing of the first or second embodiment, the control unit 120 reads an image at that time or a past video (loop recorded) from the recording device. All or part of the recording device is stored permanently (not erased) in the recording apparatus (becomes a second storage unit). Thereby, when analyzing later, even when only the recording device is used, it is possible to view an image when another object enters the alarm region or a video earlier than that. Further, the medium for recording the video on the recording apparatus may be a portable medium.

  In FIG. 11, an example in which the camera 310 is provided in the configuration of the monitoring system of the second embodiment is shown, but in this modification, the camera 310 may be provided in the configuration of the monitoring system of the first embodiment. When the camera 310 is installed (in any of the first and second embodiments), the video shot by the camera 310 may be stored together with the distance image and the infrared image, or only the video of the camera 310 is stored (recorded). May be.

  Although the embodiments to which the present invention is applied have been described above, the present invention is not limited to these embodiments.

  In the embodiment described above, the movement of the specific object is detected from the distance image of the rider 110 or the infrared image of the thermal camera 210. In addition to this, a control signal for moving the specific object is detected, The alarm area may be set as a specific object that has moved into the monitoring area.

  In the above-described embodiment, one specific object has been described as an example of the specific object. However, there may be a plurality of specific objects. For example, a plurality of specific objects are detected from the distance image of the rider 110 and the infrared image of the thermal camera 210, and an alarm area is set for each specific object.

  In the above-described embodiment, the alarm region is set around the specific object. However, after the specific object is detected, the distance between the specific object and another object is calculated one by one, and the distance is equal to or less than the predetermined distance. By determining whether or not, an alarm signal may be output.

  Moreover, although the working place which carries hot metal was demonstrated to the example, this is an example to the last, and it can apply also to another high temperature object. For example, the present invention can be suitably used in a work place where high-temperature molten steel or other molten metal is transported or transported as with hot metal.

  In addition, the present invention can be variously modified based on the configurations described in the claims, and these are also within the scope of the present invention.

100 monitoring system,
110 riders,
120 control unit,
123 RAM,
124 HDD,
130 display,
140 alarm,
210 thermal camera,
300 hot metal hot pot,
310 camera,
400 Parts above a predetermined temperature,
450 objects.

Claims (16)

A monitoring system for monitoring the surroundings of a predetermined object in an area to be monitored,
A distance image acquisition unit that outputs a distance image showing a distribution of distance values obtained by scanning laser light toward the region;
Detecting the movement of the specific object in the region;
In the distance image acquired from the distance image acquisition unit, an alarm region is set in a predetermined range so as to include the specific object, and another object different from the specific object is detected from the distance image. A control unit that outputs an alarm signal when the detected other object is present in the alarm region;
Having a monitoring system. A first storage unit that stores in advance the feature quantity of the specific object;
When the object is detected from the distance image acquired from the distance image acquisition unit, the control unit obtains a feature amount of the detected object, and stores the detected feature amount of the object and the first storage unit Detecting the specific object by comparing with the feature amount of the specific object,
The monitoring system according to claim 1, wherein movement of the specific object is detected from the distance image acquired in time series from the distance image acquisition unit. A thermal camera installed at a position close to the distance image acquisition unit, imaging the region from substantially the same direction as the distance image acquisition unit, and outputting an infrared image in which the temperature distribution of the region is detected; ,
The control unit detects a portion having a predetermined temperature or higher in the infrared image acquired from the thermal camera, and detects an object in the distance image acquired from the distance image acquisition unit in a direction corresponding to the portion. By detecting the specific object,
The monitoring system according to claim 1, wherein movement of the specific object is detected from a plurality of the distance images acquired in time series from the distance image acquisition unit. The control unit detects the position of the specific object moving from the plurality of distance images acquired in time series from the distance image acquisition unit,
The monitoring system according to claim 2, wherein the alarm area is moved according to the position of the specific object.   The monitoring system according to claim 4, wherein the warning area set by the control unit is wider in front of the specific object in the moving direction than in front of the specific object in the moving direction. A second storage unit;
The controller is
The monitoring system according to claim 1, wherein the distance image at the time when it is determined that the other object exists in the alarm area is stored in the second storage unit. A temporary storage unit for temporarily storing the distance image;
The controller is
A plurality of the distance images acquired in time series from the distance image acquisition unit are temporarily stored in the temporary storage unit for a predetermined time,
The past distance image stored in the temporary storage unit until the time when it is determined that the other object is present in the alarm area together with the distance image when it is determined that the other object is present in the alarm area. Is stored in the second storage unit. A second storage unit;
A visible light camera that captures the region and outputs a visible light image, or a thermal camera that detects a temperature distribution of the region and outputs an infrared image;
The controller is
The time point when the other object is determined to be present in the alarm area, or the time-series visible light image or infrared image for a predetermined time including the time point is stored in the second storage unit. The monitoring system as described in any one of -5. Using a monitoring system having a distance image acquisition unit that outputs a distance image showing a distribution of distance values obtained by scanning a laser beam toward an area to be monitored, the area is determined in advance. A monitoring method for monitoring the surroundings of a specified object,
Detecting the movement of the specific object within the region (a);
(B) setting an alarm region in a predetermined range so as to include the specific object in the distance image acquired from the distance image acquisition unit;
Detecting another object different from the specific object from the distance image and alerting when the detected other object is present in the alarm region (c);
Monitoring method. The monitoring system includes a first storage unit that stores in advance the characteristic amount of the specific object,
In the step (a), when an object is detected from the distance image acquired from the distance image acquisition unit, a feature amount of the detected object is obtained, and the detected feature amount of the object and the first storage unit Comparing the feature quantity of the specific object stored in (d1) to detect the specific object;
Detecting the movement of the specific object from the distance image acquired in time series from the distance image acquisition unit (d2);
The monitoring method according to claim 9, comprising: The monitoring system is installed at a position close to the distance image acquisition unit, images the region from substantially the same direction as the distance image acquisition unit, and outputs an infrared image in which the temperature distribution of the region is detected And further having
In the step (a), a part having a predetermined temperature or higher is detected in an infrared image obtained from the thermal camera, and an object is added to the distance image obtained from the distance image obtaining unit in a direction corresponding to the part. Detecting the specific object by detecting (e1),
The monitoring method according to claim 9, further comprising: detecting a movement of the specific object from a plurality of the distance images acquired in time series from the distance image acquisition unit. Detecting the position of the specific object moving from a plurality of the distance images acquired in time series from the distance image acquisition unit,
The monitoring method according to claim 10 or 11, further comprising a step (f) of moving the alarm area in accordance with a position of the specific object.   The monitoring method according to claim 12, wherein the warning area is wider in front of the specific object in the movement direction than in front of the specific object in the movement direction. The monitoring system has a second storage unit,
14. The method according to claim 9, further comprising a step (g) of storing the distance image at the time when it is determined in step (c) that the other object is present in the alarm area in the second storage unit. Monitoring method described in 1. The monitoring system has a temporary storage unit that temporarily stores the distance image,
A step (h) of temporarily storing a plurality of the distance images acquired in time series from the distance image acquiring unit in the temporary storage unit for a predetermined time;
Along with the distance image at the time when it is determined in step (g) that the other object exists in the alarm area, the distance image is stored in the temporary storage unit until the time when it is determined that the other object exists in the alarm area. The monitoring method according to claim 14, further comprising a step (i) of storing the past distance image in the second storage unit. The monitoring system includes a second storage unit, a visible light camera that captures the region and outputs a visible light image, or a thermal camera that detects a temperature distribution of the region and outputs an infrared image.
A step (j) of storing the visible light image or the infrared image in a time series for a predetermined time including the time point when it is determined that the other object exists in the alarm region (j); The monitoring method according to claim 9, comprising: