JP6910913B2 - Monitoring device - Google Patents

Description

The present invention relates to a monitoring device that changes the shooting direction according to the position of an object that has entered the monitoring area and tracks and shoots the object.

As a conventional imaging device that automatically tracks and images a target object using a camera (PTZ camera) capable of controlling pan, tilt, and zoom (PTZ), the following Patent Document 1 describes before object detection. Describes that the camera is set to the wide-angle side, and when an object is detected by the camera, it zooms up based on the size of the object. Immediately after the object is detected, it is shown that the zoom is performed at a low speed so as not to lose sight of the object.

Japanese Patent No. 4241742

When an object is tracked and photographed with a camera based on the detection result of the object by the laser sensor, the angle of view of the camera may change significantly depending on the detection position immediately after the object is detected, or the accuracy of the predicted position of the object may not be high. .. As a result, if the zoom control is performed immediately after the detection, the object may be removed from the angle of view.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a monitoring device capable of stably capturing an object within the angle of view immediately after the detection of the object to be tracked. And.

(1) The monitoring device according to the present invention is a device that tracks and photographs an object that has entered the monitoring area, and is an object detection unit that detects the position of the object and an imaging unit that can change the imaging direction and control zoom. And a control unit that controls the imaging unit based on the detection result of the object detection unit, the control unit limits the zoom control in a predetermined initial period after the object is first detected. ..

(2) In the monitoring device according to (1) above, the control unit may be configured to prohibit the zoom control as a limitation of the zoom control.

(3) In the monitoring device according to (1) above, the control unit may be configured to limit zoom-in control while allowing zoom-out control as a limitation of zoom control.

(4) In the monitoring device according to (1) or (3) above, the control unit keeps the size of the image of the object in the image at a predetermined reference size by the zoom control, and controls the zoom. As a limitation, the zoom magnification may be set to be lower than the magnification corresponding to the reference size.

(5) In the monitoring device according to (1) to (4) above, the control unit has a configuration in which the initial period is until the moving speed of the object obtained from the detection result of the object detection unit stabilizes. can do.

(6) In the monitoring device according to the above (1) to (4), when the object is captured in the central region of the image by the control of the photographing direction of the imaging unit, the control unit is in the initial period. Even before the lapse of time, the restriction on the zoom control can be released.

According to the present invention, it is possible to obtain a monitoring device capable of stably capturing an object within the angle of view immediately after the detection of the object to be tracked.

It is a schematic diagram which shows the schematic structure of the monitoring system which concerns on embodiment of this invention. It is a flow figure which shows the schematic operation of the monitoring apparatus which concerns on embodiment of this invention. It is a block diagram which shows the schematic structure of the monitoring apparatus which concerns on embodiment of this invention. It is a schematic flow chart of the process by a mode switching means, a position prediction means, and a camera control means. It is a transition diagram regarding a control mode. It is the figure which showed the control content performed in each control mode in a table format. It is a schematic flow chart of the control mode determination process of FIG. It is a schematic flow diagram in the case of limiting the zoom function in the generation / transmission process of the camera control command of FIG.

Hereinafter, as an embodiment of the present invention (hereinafter referred to as an embodiment), a monitoring system 1 including a monitoring device according to the present invention will be described with reference to the drawings.

FIG. 1 is a schematic diagram showing a schematic configuration of the monitoring system 1 according to the embodiment. The monitoring system 1 includes a monitoring device 2 and a center device 3. The monitoring device 2 and the center device 3 are communicably connected to each other.

The monitoring device 2 is installed in a place, a building, or the like where the monitoring area 4 to be monitored is set, and tracks and photographs an object (person, vehicle, etc.) that has invaded the monitoring area 4. The monitoring device 2 includes an object detection unit 5, an imaging unit 6, and a control unit 7, and at least the object detection unit 5 and the imaging unit 6 are installed at positions facing the monitoring area 4. For example, the monitoring area 4 is set outdoors, and the object detection unit 5 and the image pickup unit 6 are installed on the outer wall surface of the building, a support column erected adjacent to the monitoring area 4, and the like. On the other hand, the control unit 7 can be installed in a place close to the object detection unit 5 and the image pickup unit 6, for example, the object detection unit 5 and the image pickup unit 6 are installed outdoors, and the control unit 7 is installed indoors. As such, it can be placed at a position separated from the object detection unit 5 and the image pickup unit 6. Further, each function of the control unit 7 may be provided in the object detection unit 5 and the image pickup unit 6.

FIG. 2 is a flow chart showing a schematic operation of the monitoring device 2. When the object detection unit 5 detects an abnormal event (for example, an intrusion of a suspicious person or a vehicle into the monitoring area 4) that occurs in the monitoring area 4 (step S10), the object detection unit 5 transmits the detection information to the control unit 7 (step). S11). The control unit 7 generates a camera control command as a control instruction to the image pickup unit 6 based on the detection information of the object (for example, the position of the object, the moving speed, and the moving direction) (step S12). The imaging unit 6 controls the camera according to the camera control command from the control unit 7, and takes a picture while following the movement of the object that has entered the monitoring area 4 (step S13).

The monitoring area 4 is set in a semicircle with a radius of several tens of meters [m] (for example, 20 m) centered on the monitoring device 2, for example. The monitoring area is not limited to this example and is appropriately determined by security planning.

The center device 3 is installed in a facility such as a monitoring center operated by a security company or the like, and is usually composed of one or a plurality of computers. Further, the center device 3 is connected to one or more monitoring devices 2 via a network. In the monitoring center, for example, various devices are controlled by the center device 3, the abnormality signal received from the monitoring device 2 is recorded, and the abnormality information and the captured image captured by the imaging unit 6 are displayed on the display, and the observer Is monitoring the monitoring area.

FIG. 3 is a block diagram showing a schematic configuration of the monitoring device 2. Hereinafter, the configuration of the monitoring device 2 shown in FIG. 3 will be described.

For example, the object detection unit 5 detects the position of an object existing in the monitoring area 4 by performing spatial scanning on the monitoring area 4 at a predetermined cycle using a beam-shaped exploration signal and receiving a reflection signal from the object. do. In addition, the object detection unit 5 can calculate the moving speed and the moving direction of the object by using the position detection results at a plurality of times.

The object detection unit 5 includes a communication means 51, a distance measuring means 52, a storage means 53, and a monitoring control means 54.

The communication means 51 is connected to the control unit 7, receives the security start signal and the security release signal output from the control unit 7, and inputs the signal to the monitoring control means 54. Further, when the monitoring control means 54 determines the existence of an intruding object in the monitoring area 4, the communication means 51 transmits a detection signal including its own address information to the control unit 7. For example, detection information and tracking information (tracking ID, whether it is a new object, etc.) are transmitted to the control unit 7 as detection signals.

The distance measuring means 52 is basically a means for periodically scanning the monitoring area 4 to calculate the distance to an object existing in the monitoring area 4. In the present embodiment, the distance measuring means 52 is configured by using a laser sensor, and emits laser light as an exploration signal. For example, the laser sensor is installed so that the emission direction of the laser light is horizontal or has a constant depression angle.

Specifically, the distance measuring means 52 repeats scanning at a predetermined period (for example, 60 milliseconds) with respect to a horizontal angle range facing the monitoring area 4 centered on the laser sensor. Distance measurement by the distance measuring means 52 is performed by using the flight time method (TOF method: Time of Flight) at predetermined angle steps (for example, 0.25 °) within the scanning angle range. That is, the time required from the emission of the laser pulse to the reception is measured, and the distance to the object reflecting the laser is calculated from the time and the speed of light.

The distance measurement data obtained as measurement data by the distance measurement means 52 is represented by a scanning angle (direction) and a distance, and the position of the laser light reflection point on the object with the laser sensor as a viewpoint is given by the distance measurement data. Specifically, the distance measurement data is information consisting of a collection of a plurality of measurement point data in which the angle (direction) of transmission / reception of the laser beam and the distance to the reflection point are associated with each other. If the reflected light is not returned within the predetermined time, it can be considered that there is no object within the distance that the laser beam can irradiate, and the distance measuring means 52 uses the predetermined pseudo data (for example, monitoring) as the distance. Set the distance value to the outer circumference of the region 4, an appropriate value equal to or greater than the effective measurement distance by the laser beam, etc.). The distance measuring data obtained by the distance measuring means 52 is stored in the storage means 53.

The distance measuring means 52 is not limited to a laser sensor, and can be configured by using various sensors that can detect the position of an object, such as an ultrasonic sensor.

The storage means 53 is a storage device composed of an HDD (Hard Disk Drive), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like, and includes various setting information and a program for operating the object detection unit 5. Remember. For example, the storage means 53 stores address information for identifying the object detection unit 5 itself. Further, the storage means 53 contains the monitoring area information indicating the monitoring area 4 set as the range to be monitored by the object detection unit 5, the reference data generated by the monitoring control means 54, and the distance measuring means 52. The distance measurement data for the past predetermined cycle and the tracking information of the moving object (invading object) acquired in the above are stored.

Here, the reference data is data to be compared with the current ranging data in order to extract a moving object newly appearing in the monitoring area 4 in the tracking process for tracking the moving object. Specifically, the reference data is generated from the distance measurement data acquired at any past time point from the start of scanning by the distance measurement means 52 to the present. For example, existing objects such as plants and outer walls acquired by scanning in a state where no moving object exists in the monitoring area 4 are used as reference data. The reference data can be stored, for example, in the form of a table in which the distance is associated with the angle (direction).

The tracking information is information used in the tracking process for tracking a moving object newly appearing in the monitoring area 4 over a plurality of cycles. In the tracking information, the position and size in each scanning cycle are associated and stored for each moving object. In addition, the tracking information can store identification information (vehicle, person, etc.) of the object. Further, since a plurality of moving objects may appear in the monitoring area 4, an identifier (object ID) for distinguishing the objects is attached. In this case, the tracking information is stored in association with the object ID.

The monitoring control means 54 is composed of a microcomputer including a CPU (Central Processing Unit), a ROM, a RAM, and peripheral circuits thereof, and the movement that appears in the monitoring area 4 when the microcomputer reads a program from the storage means 53 and executes it. Calculate the position of an object and its movement speed.

When the security start signal is input from the control unit 7 via the communication means 51, the monitoring control means 54 outputs a drive signal to the distance measuring means 52 and starts driving the distance measuring means 52. As a result, the emission of the laser beam by the distance measuring means 52, the driving of the scanning mirror that changes the scanning angle of the laser beam, and the like are started. On the other hand, the drive control unit outputs a drive stop signal to the distance measuring means 52 when the security release signal is input from the control unit 7, and stops the driving of the distance measuring means 52 when the scanning at that time is completed. As a result, the emission of laser light and the driving of the scanning mirror are stopped.

Further, the monitoring control means 54 compares the current ranging data with the reference data and detects a moving object appearing in the monitoring area 4. Specifically, the difference between the distance value for each scanning angle obtained from the current distance measurement data and the distance value for each angle stored in the reference data was calculated for each corresponding angle, and the distance value changed. The measurement point of the current distance measurement data at the angle is used as the detection point. Then, in the detection point group, the adjacent detection points that are considered to have changed the distance value due to the same object to be measured are grouped as object candidates.

Further, the monitoring control means 54 associates the object candidates detected in the previous cycle and the current cycle with each other based on the distance and the size. That is, when the distance between the objects detected in both cycles is within the threshold value and the magnitude fluctuation is within the threshold value, the object candidates are associated. In addition, the movement speed and the movement direction are calculated from the tracking information generated by the association.

The image pickup unit 6 can change the shooting direction in order to track and shoot a moving object. Further, the imaging unit 6 can perform zoom control in order to obtain an object image having a sufficient resolution for an object or the like that is far from the monitoring device 2. That is, the imaging unit 6 of the present embodiment is configured by using a camera (PTZ camera) capable of controlling pan, tilt and zoom (PTZ), and is a control unit based on the detection information of the intruding object detected by the object detection unit 5. According to the instruction of 7, the intruding object is imaged by performing PTZ control so that the invading object fits within the angle of view, particularly so as to be in the center of the angle of view. The camera of the imaging unit 6 is installed at a position facing the monitoring area 4 together with the laser sensor of the object detection unit 5 as described above. Here, the imaging unit 6 can be installed at the same position as the object detection unit 5, or at a position shifted in the vertical direction with respect to the object detection unit 5 or at another location near the object detection unit 5. It may be installed.

The imaging unit 6 includes a camera driving means 61, an imaging means 62, a communication means 63, and a storage means 64.

The camera driving means 61 includes a driving mechanism for changing the shooting direction (pan, tilt) of the camera and a driving mechanism for driving the zoom lens of the camera to change the angle of view, and these are based on a control instruction from the control unit 7. Operates the drive mechanism to control pan and tilt and zoom control.

The image pickup means 62 is composed of, for example, a camera using an image pickup element, and photographs a monitoring area or an intruding object.

The communication means 63 receives the camera control signal from the control unit 7. Further, the communication means 63 transmits the captured image by the imaging means 62 to the center device 3 via the control unit 7.

The storage means 64 is a storage device composed of an HDD, a ROM, a RAM, and the like, and stores captured images. Further, the storage means 64 stores the home position of the camera (angle of view when an intruding object is not detected).

The control unit 7 is communicably connected to the object detection unit 5 and the image pickup unit 6, outputs control signals to them, and inputs detection signals and captured images from them. Further, the control unit 7 is communicably connected to the remote center device 3, receives a control signal for the monitoring device 2 from the center device 3 and operates, and receives an abnormal signal or a captured image detected in the monitoring area 4. It is transmitted to the center device 3. For example, the user performs an operation for starting or canceling the monitoring of the monitoring area 4 in the operation unit provided in the monitoring device 2, or receives an instruction for starting or canceling the monitoring from the center device 3. , The control unit 7 sets the monitoring state of the monitoring area 4 to start or release, and transmits a security start signal or a security release signal to the object detection unit 5.

The control unit 7 includes a mode switching means 71, a position prediction means 72, a camera control means 73, a communication means 74, a storage means 75, and a determination means 76. The control unit 7 is composed of a microcomputer including a CPU, ROM, RAM, and peripheral circuits thereof, and the microcomputer reads a program from the storage means 75 and executes the program to execute the mode switching means 71, the position predicting means 72, and the camera control means. It functions as 73, a determination means 76, and the like.

The mode switching means 71 switches the control mode of the camera provided in the camera control means 73. The position predicting means 72 calculates the predicted position of the moving object after a predetermined time from the detection information (position of the object, moving speed, etc.) received from the object detecting unit 5. The camera control means 73 generates and outputs a control instruction to the imaging unit 6 based on the control mode set by the mode switching means 71 and the predicted position calculated by the position prediction means 72. These means 71 to 73 will be further described later.

The communication means 74 performs communication between the object detection unit 5 and the image pickup unit 6 and the control unit 7 in the monitoring device 2, and communication with the center device 3. For example, the communication means 74 transmits a security start signal or a security release signal to the object detection unit 5. Further, an abnormality signal generated when an abnormality is detected in the monitoring area 4 and a captured image are transmitted to the center device 3.

The storage means 75 is a storage device composed of an HDD, a ROM, a RAM, and the like, and stores various setting information, a program for operating the control unit 7, and the like. For example, the storage means 75 stores the detection information of the object and also stores the current control mode of the moving object. Further, the storage means 75 stores a table in which parameters such as a designated time and zoom conditions set in advance corresponding to each control mode are defined. Further, the relative positions of the object detection unit 5 and the image pickup unit 6 are also stored in advance in the storage means 75.

The determination means 76 determines the abnormality in the monitoring area 4 based on the detection signal of the object detection unit 5 or the like in the state where the monitoring state is started.

Hereinafter, the mode switching means 71, the position prediction means 72, and the camera control means 73 will be described in detail.

FIG. 4 is a schematic flow chart of processing by the mode switching means 71, the position prediction means 72, and the camera control means 73. When the control unit 7 acquires the detection information from the object detection unit 5, the process is started (step S21), and the mode switching means 71 determines the control mode based on the detection information (step S22). When the control mode is determined, the position predicting means 72 reads the designated time corresponding to the control mode from the storage means 75 and sets it (step S23), and calculates the predicted position (step S24). The camera control means 73 generates a camera control command based on the calculated predicted position and the zoom condition corresponding to the control mode, and transmits the camera control command to the imaging unit 6 (step S25).

The camera control means 73 has at least two control modes according to the moving speed of the object, controls the shooting direction of the camera of the imaging unit 6 based on one of the control modes, and the mode switching means 71 is the camera control means. The control mode in 73 is switched. For example, if the difference in the moving speeds of the objects corresponding to the two control modes is expressed as relatively high speed / low speed, the mode switching means 71 responds to the moving speed of the object obtained from the detection result of the object detection unit 5. , The control mode is switched from the low speed side to the high speed side, and the control mode is switched from the high speed side to the low speed side, respectively, based on predetermined switching criteria.

Here, assuming that the switching criterion from the low-speed side control mode to the high-speed side control mode is the first criterion and the switching criterion from the high-speed side control mode to the low-speed side control mode is the second criterion, the first criterion is the first criterion. The control mode is set to be easier to switch than the two criteria. The features of this control mode switching will be specifically described.

FIG. 5 is a transition diagram relating to the control mode in the present embodiment. As shown in FIG. 5, the camera control means 73 of the present embodiment has three control modes: a high-speed movement mode, a medium-speed movement mode, and a low-speed movement mode. Specifically, in FIG. 5, a high-speed movement mode, a medium-speed movement mode, and a low-speed movement mode are arranged in order from the top, and switching from a certain control mode to another control mode is indicated by an arrow. For example, the arrow from the high-speed movement mode to the medium-speed movement mode indicates the switching from the high-speed movement mode to the medium-speed movement mode.

Further, FIG. 6 is a diagram showing the control contents performed in each control mode in a table format. FIG. 6 corresponds to the above-mentioned table in which parameters such as a specified time and zoom conditions set in advance corresponding to each control mode are defined, and the table is stored in the storage means 75 of the control unit 7 as described above. NS. In FIG. 6, the designated time and the zoom condition are defined for each control mode. Here, the value shown in the zoom condition is the value of the ratio of the size of the object image to the angle of view in the height direction (represented by the symbol κ), and the size of the object image with respect to the range in the height direction of the captured image is Zoom control is performed so as to have the ratio. Specifically, in the example shown in FIG. 6, κ = 1/3 in the low-speed movement mode, κ = 1/4 in the medium-speed movement mode, and κ = 1/5 in the high-speed movement mode. Here, under the condition that the distance to the object is the same, the larger the κ, the larger the zoom magnification. In FIG. 6, the difference between the modes related to the zoom magnification is symbolically shown by the description of "telephoto", "wide angle" and the like.

The high-speed movement mode is a mode set when the object is moving at high speed. In this mode, the camera control means 73 controls the camera so as to zoom out and shoot more than the other two control modes. At the same time, the position predicting means 72 makes the designated time longer than the other two control modes in calculating the predicted position.

The low-speed movement mode is a mode that is set when the object is moving at a low speed. In this mode, the camera control means 73 controls the camera so as to zoom in and shoot more than the other two control modes. , The position predicting means 72 shortens the designated time in calculating the predicted position as compared with the other two control modes.

The medium-speed movement mode is a mode set when the object is moving at a medium speed, and controls between the high-speed movement mode and the low-speed movement mode.

Here, for each combination consisting of any two of the three control modes, the above-mentioned first reference and second reference are set according to the relative magnitude of the corresponding speeds of the two control modes. That is, among the arrows shown in FIG. 5, the switching criteria corresponding to those going from bottom to top correspond to the above-mentioned first criteria, and conversely, the switching criteria corresponding to those going from top to bottom correspond to the above-mentioned second criteria. Corresponds to the standard.

In the present embodiment, the switching reference is set based on the moving speed and the duration of the moving speed on the high speed side or the low speed side. Specifically, the first criterion is that the state in which the moving speed of the object is equal to or higher than the predetermined first reference speed continues for the first reference time, and the second criterion is that the moving speed of the object is the predetermined first reference speed. By assuming that the state of being below the second reference speed continued for the second reference time and setting the first reference time shorter than the second reference time, the first reference sets the control mode more than the second reference. It is set to be easy to switch. Further, in the present embodiment, the first reference speed is set to a value larger than the second reference speed.

For example, in the switching reference between the low-speed movement mode and the medium-speed movement mode, the first reference time and the reference speed are set to 0.5 seconds [s] and 1.0 m / sec [m / s], respectively. The reference time and the reference speed of the second can be set to 5.0 seconds and 0.5 m / s, respectively. In this case, the criterion for switching from the low-speed movement mode to the medium-speed movement mode, which is the first reference, is that the speed of 1.0 m / s or more continues for 0.5 seconds, and the medium-speed movement mode, which is the second reference, is used. The criterion for switching from to low speed movement mode is that the speed of 0.5 m / s or less continued for 5.0 seconds.

Further, for example, in the switching reference between the medium speed movement mode and the high speed movement mode, the first reference time and the reference speed are set to 0.5 seconds and 4.0 m / s, respectively, and the second reference time and the reference speed are set. Can be set to 5.0 seconds and 2.0 m / s, respectively. In this case, the standard for switching from the medium-speed movement mode, which is the first standard, to the high-speed movement mode is that the speed of 4.0 m / s or more continues for 0.5 seconds, and the high-speed movement mode, which is the second standard, is used. The criterion for switching to the medium speed movement mode is that the speed of 2.0 m / s or less continues for 5.0 seconds.

Regarding the switching reference between the low-speed movement mode and the high-speed movement mode, for example, the first reference time and the reference speed are set to 0.5 seconds and 4.0 m / s, respectively, and the second reference time and the reference speed are set. Can be set to 5.0 seconds and 0.5 m / s, respectively.

FIG. 7 is a schematic flow chart of the control mode determination process S22 of FIG. In FIG. 7, V1 to V4 are reference speeds, T1 and T2 are reference times, and in the example of FIG. 5, V1 = 4.0 m / s, V2 = 2.0 m / s, V3 = 1.0 m /. s, V4 = 0.5 m / s, T1 = 5 seconds, T2 = 0.5 seconds.

The mode switching means 71 reads and acquires the current control mode stored in the storage means 75 (step S30). When the current control mode is the high-speed movement mode, the mode switching means 71 determines the control mode when the movement speed continues to be the reference speed V4 or less for the reference time T1 or more (in the case of “Yes” in step S31). Is switched to the low-speed movement mode (step S39), and when the state in which the movement speed is the reference speed V2 or less continues for the reference time T1 or more (when “Yes” in step S32), the control mode is switched to the medium-speed movement mode (step S32). Step S36). On the other hand, if neither of them is present (when both are "No" in steps S31 and S32), the high-speed movement mode is maintained (step S33).

Further, when the current control mode is the medium speed movement mode, the mode switching means 71 switches to the high speed movement mode when the movement speed of V1 or higher continues to be T2 or higher (in the case of "Yes" in step S34). In step S33), when the movement speed of V4 or less continues to be T1 or more (in the case of "Yes" in step S32), the mode is switched to the low speed movement mode (step S39). (In the case of "No"), the medium speed movement mode is maintained (step S36).

Further, when the current control mode is the low-speed movement mode, the mode switching means 71 switches to the high-speed movement mode when the movement speed of V1 or higher continues to be T2 or higher (in the case of “Yes” in step S37). S33), when the movement speed of V3 or higher continues to be T2 or higher (in the case of "Yes" in step S38), the mode is switched to the medium speed movement mode (step S36). (When both are "No"), the low-speed movement mode is maintained (step S39).

As described above, the switching reference is set so that the mode switching from the low speed side to the high speed side is more likely to occur than the reverse mode switching. For example, the duration of the movement speed is set as a short standard. As a result, it is possible to quickly start camera control for changing the shooting direction for an object moving at a high speed, so that it is difficult to remove the object moving at a high speed from the angle of view. On the other hand, for an object having a low moving speed, the camera is controlled after waiting until the influence of the fluctuation of the speed is reduced, so that it is difficult to remove the object from the angle of view.

Further, the switching reference includes a reference regarding the moving speed, and in the present embodiment, the first reference speed is set to a value larger than the second reference speed as described above. That is, the threshold value of the moving speed for switching the mode from the low speed side to the high speed side is set larger than the threshold value of the moving speed for switching from the high speed side to the low speed side. As a result, even if there are variations or errors in the acquired speed information, the mode can be switched when the speed can be surely set to the moving state on the high speed side, so that inappropriate mode switching can be prevented. ..

It should be noted that the threshold value of the movement speed for mode switching may be the same from the low speed side to the high speed side and from the high speed side to the low speed side, and may be used as a switching reference in which only the duration is different. For example, in the switching reference between the high-speed movement mode and the medium-speed movement mode shown in FIG. 5, the first reference speed is 4.0 m / s and the second reference speed is 2.0 m / s. Both can be set to 3.0 m / s.

Further, the speed mode is not limited to the above three modes, and may be set to two modes, a high-speed movement mode and a low-speed movement mode, without providing the medium-speed movement mode, or another mode such as a stationary mode or an initial mode. A mode may be provided and subdivided.

Immediately after the object is detected, accurate speed information may not be acquired. Therefore, the initial mode may be set regardless of the calculated speed information. It is preferable that the initial mode is a mode in which the camera is controlled so as to zoom out and shoot in the same manner as the high-speed movement mode, giving priority to keeping the moving object within the angle of view. Then, when the predetermined time elapses and the speed becomes stable, the mode is switched according to the flow chart of FIG. At this time, the current mode may be a high-speed movement mode.

As described above, the position predicting means 72 calculates the predicted position of the moving object after the designated time based on the detection information from the object detection unit 5. The designated time is set in advance according to the moving speed of the object. As an example, as shown in FIG. 6, in the present embodiment, it is 1.5 seconds in the high-speed movement mode, 0.8 seconds in the medium-speed movement mode, and 0.2 seconds in the low-speed movement mode.

The moving speed and moving direction of the object detected by the object detection unit 5 tend to be unstable on the low speed side, and conversely tend to be stable on the high speed side. In addition, the speed acquired by the laser sensor tends to vary, and may differ from the actual speed. Therefore, if the designated time is set longer in the control mode on the low speed side, the actually moved position and the predicted position deviate from each other, and the object is likely to deviate from the angle of view of the camera by the camera control based on the predicted position. Further, in the case of an object having a low moving speed, the moving distance per hour is small and the moving direction is liable to change, so that it is not highly necessary to change the angle of view of the camera significantly in order to fit the object within the angle of view.

Therefore, the control mode on the low speed side is set to be shorter than the control mode on the high speed side, and the predicted position is calculated using the specified time, so that the moving object is kept within the angle of view of the camera and the moving object is moved. An image with smooth movement can be obtained.

On the other hand, if the specified time is set short in the control mode on the high-speed side, there is a risk that the moving object will deviate from the angle of view of the camera due to the influence of the reaction time from the instruction of the camera control to the execution. be. Further, in the case of an object having a high moving speed, the moving direction and the moving speed are stable, and even if the distance from the current detection position to the predicted position is set large, it is difficult to deviate from the actual position after the specified time.

Therefore, the control mode on the high-speed side is set to have a longer designated time than the control mode on the low-speed side, and the predicted position is calculated using the designated time, so that the moving object can be accommodated within the angle of view of the camera.

The specific value of the designated time is not limited to the example shown in FIG. 6, and it is preferable to set it appropriately according to an experiment or the like.

When the predicted position calculated based on the predetermined time is outside the photographable area of the imaging unit 6, the position predicting means 72 is configured to correct the predicted position so that it is within the photographable area. You can also. That is, the predicted position is set within the area where shooting can be performed by performing camera control such as changing the shooting direction. Further, the position predicting means 72 may be configured to correct the predicted position so that it is within the angle of view when the predicted position calculated based on the predetermined time is outside the maximum angle of view of the camera. can. In these configurations, for example, the predicted position can be changed within the target area by shortening the designated time. The designated time can be shortened to a value obtained by multiplying the value stored in advance in the storage means 75 by a predetermined magnification smaller than 1. Further, the designated time may be shortened in multiple steps by gradually reducing the magnification until the predicted position falls within the target region. According to this, it becomes possible to track and shoot a moving object up to the maximum angle of view of the camera.

As described above, the camera control means 73 generates a signal for giving a control instruction to the imaging unit 6 according to the control mode and the predicted position. Specifically, the camera control means 73 controls the amount of pan, tilt, and zoom of the camera and the speed thereof by the control signal given to the camera drive means 61 of the image pickup unit 6.

Here, in the control of the shooting direction (pan, tilt), it is preferable that the moving object is captured in the center of the angle of view, and in the zoom control, the moving object is captured with a predetermined size. The predetermined magnitude in the zoom control is defined by the above-mentioned zoom condition κ for each control mode.

The configuration in which the position prediction means 72 corrects the predicted position when the predicted position based on the designated time is outside the imageable area of the imaging unit 6 or outside the maximum angle of view of the camera is described above. On the other hand, in this case, instead of correcting the predicted position, the camera control means 73 may not control the shooting direction, that is, may not control the camera to be directed to the predicted position. According to this, since the object moving outside the maximum angle of view of the camera is not tracked, it is possible to quickly move to shooting another object or the like.

Further, the camera control means 73 predicts when the difference in orientation between the current position and the predicted position of the moving object with respect to the camera is less than a predetermined threshold angle, as compared with the case where the difference is equal to or more than a predetermined threshold angle. The operation of directing the shooting direction to the position may be performed gently. If the difference in orientation between the current position and the predicted position is less than a predetermined threshold angle (for example, less than 15 degrees) and the shooting direction is changed at the same operating speed as usual, camera control is completed faster than the movement of the object. , The moving object tends to deviate from the center of the angle of view, and when the moving direction of the object changes, it may deviate from the angle of view. Further, when the difference in orientation is less than a predetermined threshold angle, the moving object is unlikely to deviate from the angle of view even if the shooting direction is gently controlled. Therefore, it is preferable to gently direct the shooting direction to the predicted position. According to this, it becomes easier to continue to capture a moving object at the center of the angle of view while obtaining a smooth image. The operation of directing the shooting direction to the predicted position can be slowed down, for example, by increasing the response time constant of the control of the shooting direction and reducing the speed of the control operation of the shooting direction.

Further, an example of controlling the shooting direction of the imaging unit toward the predicted position when the predicted position is within the maximum angle of view of the camera has been described, but the present invention is not limited to this. For example, when the predicted position is located in the central region of the current image, the shooting direction may not be controlled. According to this, when the moving object is photographed near the center of the image, the photographing direction is not unnecessarily controlled, so that an image that is easy for the observer or the like to see can be obtained.

Immediately after a new moving object is detected, the zoom function is restricted until a predetermined initial period immediately after the detection elapses, considering that the detection accuracy of the moving speed and moving direction of the moving object may be low. The camera may be controlled. In this configuration, the limitation of the zoom function is released after the moving object can be stably photographed (tracked), so that it becomes difficult to remove the moving object from the angle of view.

FIG. 8 is a schematic flow chart when the zoom function is restricted in the camera control command generation / transmission process S25 of FIG. When the camera control means 73 acquires the detection information of the new object (step S41), the camera control means 73 limits the zoom function (step S42). In this state, the process of generating a camera control command and transmitting it to the imaging unit 6 (step S43) is repeated until a predetermined period elapses (in the case of "No" in step S44), and when the predetermined period elapses (in step S44). (In the case of "Yes"), the restriction on the zoom function is released (step S45).

As a mode of limiting the zoom control, there is one that prohibits the zoom control in general. Further, in consideration of the object of the present invention, zoom-out control for enlarging the angle of view of the camera may be allowed. Further, as for the zoom-in control, it is possible to prohibit the zoom-in control exceeding a predetermined magnification, instead of prohibiting the zoom-in control at all. Further, as described above, the camera control means 73 normally keeps the size of the image of the moving object in the image at the reference size according to the zoom condition κ, but as a limitation of the zoom control, the zoom magnification is set to the reference size. It can also be configured to be lower than the corresponding magnification. For example, κ = 1/4 in the low-speed movement mode, κ = 1/5 in the medium-speed movement mode, and κ = 1/6 in the high-speed movement mode. Further, the above-mentioned tolerance of zoom-in control and limitation of zoom-out control may be combined. For example, zoom-in control may be allowed and zoom-out may be prohibited, zoom-in control may be allowed, and zoom-in control exceeding a predetermined magnification may be prohibited. According to these points, it is possible to acquire more information on the moving object while preventing the moving object from being removed from the angle of view.

The initial period can be, for example, a period from object detection to execution of a predetermined number of camera control cycles. For example, the cycle is 0.6 seconds, and the zoom control is limited by a period in which this cycle is repeated two or three times.

Further, the initial period may be determined based on an index for determining whether or not a moving object can be tracked stably. In this case, the camera control means 73 limits the zoom control with the initial period until the index indicates that the tracking is stable. For example, the camera control means 73 can set the initial period until the moving speed of the object obtained from the detection result of the object detection unit 5 becomes stable. Judgment that the moving speed is stable can be determined, for example, from the fact that the acceleration of the object is equal to or less than a predetermined threshold value and the rate of change in speed in a predetermined period is equal to or less than a predetermined threshold value. Further, the camera control means 73 may set the initial period until the moving object is captured in the central region of the image by controlling the shooting direction of the imaging unit 6. Here, the central region can be, for example, an region corresponding to 4 blocks located in the center when the image is divided into 16 blocks of vertical 4 × horizontal 4.

In addition, the initial period is a period of a predetermined length from object detection as determined by the number of cycles described above, and the above period based on an index for determining whether or not a moving object can be tracked stably. It can be the shorter of the two. For example, when a moving object is captured in the central region of an image by controlling the shooting direction of the imaging unit 6, the camera control means 73 limits the zoom control even before the elapse of an initial period of a predetermined length. To cancel.

As described above, the monitoring device 2 detects an object such as a person or a vehicle that invades the monitoring area by the object detection unit 5 using a laser sensor or the like, and controls the PTZ camera toward the detection position to detect the invading object. It shoots and tracks, and by controlling the camera according to the moving speed of the intruding object, the intruding object is continuously captured within the angle of view of the camera.

In particular, by limiting the zoom control immediately after the object is detected and tracking the object by performing the pan / tilt control, it is difficult to remove the object immediately after the detection from the angle of view. As a limitation of zoom control, zoom control may be prohibited, zoom-out may be permitted, and zoom-in may be prohibited.

1 Monitoring system, 2 Monitoring device, 3 Center device, 5 Object detection unit, 6 Imaging unit, 7 Control unit, 51, 63, 74 Communication means, 52 Distance measuring means, 53, 64, 75 Storage means, 54 Monitoring control means , 61 camera driving means, 62 imaging means, 71 mode switching means, 72 position prediction means, 73 camera control means, 76 determination means.

Claims (6)

A monitoring device that tracks and photographs objects that have entered the monitoring area.
An object detection unit that detects the position of the object,
An imaging unit that can change the shooting direction and control the zoom,
A control unit that controls the imaging unit based on the detection result of the object detection unit is provided.
The control unit limits the zoom control for a predetermined initial period after the object is first detected.
A monitoring device characterized by. The monitoring device according to claim 1, wherein the control unit prohibits the zoom control as a limitation of the zoom control. The monitoring device according to claim 1, wherein the control unit limits zoom-in control while allowing zoom-out control as a limitation of zoom control. The control unit
The zoom control keeps the size of the image of the object in the image at a predetermined reference size.
As a limitation of the zoom control, the zoom magnification should be lower than the magnification corresponding to the reference size.
The monitoring device according to claim 1 or 3, wherein the monitoring device is characterized. The control unit according to any one of claims 1 to 4, wherein the initial period is a period until the moving speed of the object becomes stable, which is obtained from the detection result of the object detection unit. Monitoring device. The control unit is characterized in that when the object is captured in the central region of the image by the control of the shooting direction of the imaging unit, the limitation of the zoom control is released even before the lapse of the initial period. The monitoring device according to any one of claims 1 to 4.

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