JP6904811B2 - Surveillance camera device - Google Patents

Description

The present invention relates to a surveillance camera device, and more particularly to a surveillance camera device having a function of detecting a scheme that obstructs the field of view of the camera.

Conventionally, there is a system that uses a surveillance camera to monitor the intrusion of a suspicious person into a monitored space such as a store or a house. For surveillance cameras, a malicious person performs so-called visual field obstruction, mask plotting, etc., such as covering the lens surface of the surveillance camera with something, attaching tape, spraying paint, etc. , The surveillance camera may be disabled. Therefore, various measures have been taken for the purpose of detecting an abnormal state due to the act of planning. Patent Document 1 below describes that a light emitting / receiving unit provided near an imaging unit of a surveillance camera projects light in front of the camera and detects a planning action on the surveillance camera according to the reflected light of the light. ..

Japanese Unexamined Patent Publication No. 2003-87610

In the surveillance camera provided with the above-mentioned light emitting / receiving unit, if insects or the like stick to a part of the field of view of the surveillance camera or raindrops adhere to the surveillance camera, the reflected light becomes large, and there is a possibility that it is erroneously detected as a planning act.

The present invention has been made in view of the above problems, and provides a surveillance camera device that discriminates a state in which only a part of the field of view of the surveillance camera is blocked and suppresses false detection.

(1) The surveillance camera device according to the present invention has an imaging unit, a plurality of proximity sensors arranged in the vicinity of the imaging unit, and a plan abnormality that obstructs the field of view of the imaging unit based on the outputs of the plurality of proximity sensors. The plan abnormality determination means has a plan abnormality determination means for determining the above, and the plan abnormality determination means sets the total output of the plurality of proximity sensors to be equal to or greater than a predetermined first threshold value as a first determination criterion, and the output is the output. The second determination criterion is that the number of the proximity sensors, which is lower than the first threshold value and is equal to or greater than a predetermined second threshold value, is a predetermined number or more, and the first and second determination criteria are satisfied. Based on this, it is determined that the plan is abnormal.

(2) In the surveillance camera device according to (1) above, the proximity sensor is of an infrared type and has a light emitting unit that emits infrared light and a light receiving unit that receives infrared light. As the output of the proximity sensor, it is possible to acquire the integrated value of the difference value of the infrared light receiving amount of the light receiving unit between the time when the light emitting unit emits light and the time when the light emitting unit does not emit light at a predetermined time.

(3) In the surveillance camera device according to the above (1) or (2), the second determination criterion can be that the outputs of all the plurality of proximity sensors are equal to or higher than the second threshold value. ..

(4) In the surveillance camera device described in (1) to (3) above, as a reference value for the total output of the plurality of proximity sensors, a reference value for obtaining the average value of the total output during a period in which the plan is not abnormal. The first determination criterion may be configured such that the absolute value of the difference between the total output and the reference value is equal to or greater than the first threshold value.

(5) In the surveillance camera device according to (4) above, the surveillance camera device has a saturation determination means for determining that the output of the proximity sensor is in a saturated state, and the reference value acquisition means includes the plurality of proximity sensors. The reference value may be updated at predetermined time intervals when the state is not saturated, and the update may be stopped when any of the proximity sensors is in the saturated state.

(6) The surveillance camera device according to (4) or (5) above has an illuminance sensor that measures the illuminance of an infrared light component with respect to the ambient light in the imaging unit, and the reference value acquisition means has the illuminance. Can be configured to update the reference value when is greater than or equal to a predetermined value.

(7) In the surveillance camera device according to (6) above, the proximity sensor and the illuminance sensor are sensor elements integrally formed, and the output of the proximity sensor and the illuminance of the illuminance sensor are alternately output. It can be configured to be.

According to the present invention, a state in which only a part of the field of view of the surveillance camera is blocked by an insect or the like can be distinguished from a state due to a plotting action, false detection is suppressed, and the detection accuracy of the plotting abnormality is improved.

It is a schematic diagram which shows the schematic structure of the surveillance camera apparatus which concerns on embodiment of this invention. It is a flow diagram explaining the schematic operation of the surveillance camera apparatus which concerns on embodiment of this invention. It is a schematic flow chart of the update process of the reference value of the output of the proximity sensor by the reference value acquisition means. It is a schematic flow chart of the environment judgment processing by the environment judgment means. It is a schematic flow chart of the plan abnormality determination process by a plan abnormality determination means. It is a schematic flow chart of the day / night switching process by the D / N switching determination means.

Hereinafter, embodiments of the present invention (hereinafter referred to as embodiments) will be described with reference to the drawings.
FIG. 1 is a schematic diagram showing a schematic configuration of the surveillance camera device 1 according to the embodiment. The surveillance camera device 1 includes an imaging unit 2, an infrared (IR) illumination unit 4, an illuminance sensor 6, a proximity sensor 8, an IR illumination control unit 10, a control unit 12, a communication unit 14, and a storage unit 16.

The surveillance camera device 1 is a day / night camera having a day / night switching function, and operates as a color camera during the day and as a near infrared camera at night. As a result, the surveillance camera device 1 can photograph the monitoring target space day and night with the imaging unit 2 and monitor the occurrence of an abnormality such as a person invading the monitoring target space or danger. The image taken by the imaging unit 2 can be transmitted by the communication unit 14 to the monitoring center (not shown) via a communication line or the like. For example, the transmitted image is used by the observer at the monitoring center to confirm the occurrence of an abnormality. Further, the image taken by the imaging unit 2 can be recorded in the storage unit 16. For example, the recorded image is transmitted in response to a request from the monitoring center. Further, when the surveillance camera device 1 detects a plan abnormality, the communication unit 14 notifies the monitoring center.

The image pickup unit 2 includes an optical system such as a lens, an IR cut filter that is inserted and removed from the optical system, a drive unit that inserts and removes the IR cut filter, and an image pickup element such as a CCD image sensor or a CMOS image sensor. An image sensor having sensitivity in the wavelength range from visible light to infrared rays is used, and the image sensor 2 outputs a color image when the monitored space is bright based on the control signal from the control unit 12, and is monitored. When the space is dark, a black-and-white image is output as a surveillance image under low illuminance. Since light in the infrared region is not required when outputting a color image, an IR cut filter is inserted in front of the image sensor to obtain an image with improved image quality such as contrast.

Further, the imaging unit 2 includes a gain control amplifier circuit (automatic gain control: AGC) that automatically controls the gain of the camera, and an AD conversion unit that converts an analog signal into a digital signal. Further, the imaging unit 2 includes an image signal processing unit composed of a digital signal processor (DSP) or the like, and obtains image data obtained by performing predetermined image processing such as gamma processing in the image signal processing unit. Output to the control unit 12.

The IR illumination unit 4 is near-infrared light illumination, and emits light based on a control signal from the IR illumination control unit 10. By providing the IR illumination unit 4, the image pickup unit 2 can take a clear image not only when the ambient light is in a low illuminance state but also in a dark state where the illuminance is zero.

The IR illumination control unit 10 switches the lighting / extinguishing of the IR illumination unit 4 and adjusts the emission intensity based on the control of the control unit 12.

The illuminance sensor 6 includes a photodiode as a light receiving unit. The light receiving unit includes a photodiode having sensitivity from the visible light region to the infrared light region, and a photodiode having sensitivity only in the infrared light region. Here, the illuminance values obtained from these two types of photodiodes will be referred to as CLEAR illuminance value and IR illuminance value, respectively. The illuminance sensor outputs the CLEAR illuminance value and the IR illuminance value, and the illuminance value only in the visible light region can be obtained by the difference between the CLEAR illuminance value and the IR illuminance value.

The proximity sensor 8 includes a photodiode as a light receiving unit having sensitivity only in the infrared light region, and a light emitting diode (LED) as a light emitting unit that emits infrared rays. The proximity sensor 8 alternately and periodically repeatedly measures the amount of light incident on the photodiode in the non-light emitting state of the LED and the amount of light incident on the photodiode in the light emitting state of the LED, and integrates the difference values over a predetermined period. Is output. For example, when a nearby object is present, the light reflected by the proximity object with respect to the LED light is received by the photodiode, so that the presence or absence of the proximity object can be detected based on the magnitude of the photodiode output. The surveillance camera device 1 includes a plurality of proximity sensors 8, and the proximity sensors 8 detect nearby objects at a plurality of locations in the vicinity of the imaging unit 2. In this embodiment, an example including four proximity sensors 8-1 to 8-4 will be described.

The illuminance sensor 6 and the proximity sensor 8 can be one sensor element integrally formed in a small package, and the sensor element shares a light receiving part for infrared light between the illuminance sensor 6 and the proximity sensor 8. Then, the output of the illuminance sensor 6 and the output of the proximity sensor 8 are alternately output in time division. By using the proximity / illuminance sensor in which the illuminance sensor 6 and the proximity sensor 8 are integrated, it is possible to reduce the size and cost of the surveillance camera device 1. For example, using a proximity / illuminance sensor in which a plurality of proximity sensors 8-1 to 8-4 are packaged in one package, each of a plurality of locations near the imaging unit 2 that detects a proximity object and a proximity sensor 8 corresponding to the location. It can be configured to be connected with and by an optical conduit.

The proximity sensor 8 is not limited to one that emits and receives infrared light, and may be of a type that transmits and receives sound waves (including ultrasonic waves), microwaves, and millimeter waves.

The control unit 12 is configured by using a microprocessor (MPU) or the like, and performs various operations according to the program to be executed. For example, the control unit 12 functions as a D / N switching determination means 20, an environment determination means 22, a reference value acquisition means 24, a saturation determination means 26, and a plan abnormality determination means 28.

The D / N switching determination means 20 is a switching unit that performs day / night switching of the surveillance camera device 1. Specifically, the D / N switching determination means 20 determines whether the control mode is the day mode or the night mode based on the illuminance value in the visible light region obtained by the illuminance sensor 6. For example, if the illuminance value in the visible light region is equal to or greater than a predetermined threshold value, the monitored space is daytime or the like, and it is determined that the day mode is used. On the other hand, if the illuminance value in the visible light region is less than a predetermined threshold value, the monitored space is night or the like, and it is determined that the night mode is used. In the day mode, the D / N switching determination means 20 inserts an IR cut filter into the optical system of the imaging unit 2, and the imaging unit 2 photographs the monitored space with the IR cut filter inserted. On the other hand, in the night mode, the D / N switching determination means 20 removes the IR cut filter from the optical system and causes the IR illumination unit 4 to emit light via the IR illumination control unit 10.

The environment determination means 22 determines whether or not the illumination state of the IR illumination unit 4 has changed, and determines whether the infrared light component contained in the ambient light becomes ambient light with respect to the proximity sensor 8.

The reference value acquisition means 24 sets / updates the reference value for determining the proximity abnormality at a predetermined timing. Specifically, the reference value acquisition means 24 sets a reference value based on the output of the proximity sensor 8 during a period in which the visual field is not obstructed when the operation of the surveillance camera device 1 is started. For example, in the initial setting of this reference value, it can be said that the visual field interference does not occur unless the output of the proximity sensor 8 is saturated. It is also possible to perform the initial setting of the reference value after confirming that the image pickup unit 2 is not obstructed by the field of view. Further, the reference value acquiring means 24 has a function as a reference value updating means for updating the reference value in response to a time change of the environment. This process will be described later.

The saturation determination means 26 determines that the proximity sensor 8 receives a predetermined amount of light or more and its output is in a saturated state.

The plan abnormality determining means 28 determines a plan abnormality that obstructs the visual field of the imaging unit 2 based on the output of the proximity sensor 8.

The communication unit 14 transmits the image captured by the image pickup unit 2 to a remote monitoring center or the like connected by a communication line. In addition, when a plan abnormality is detected, an abnormality alarm is sent to the monitoring center or the like.

The storage unit 16 stores various information such as a program used by the control unit 12, data such as a reference value, and identification information of a surveillance camera. Further, the storage unit 16 stores the image taken by the imaging unit 2. The storage capacity of the image is set within a preset upper limit, and when the capacity of the stored image reaches the upper limit, the old image can be sequentially erased and a new image can be stored.

FIG. 2 is a flow chart illustrating a schematic operation of the surveillance camera device 1.

The control unit 12 acquires the measured values of the illuminance sensor 6 and the proximity sensor 8 (step S001). Specifically, the control unit 12 acquires the CLEAR illuminance value and the IR illuminance value from the register of the illuminance sensor 6 at predetermined time intervals. Further, the control unit 12 determines the integrated value of the difference between the output of the light receiving unit in the non-light emitting state and the light emitting state of the light emitting unit of the proximity sensor 8 at predetermined time intervals from each of the proximity sensors 8-1 to 8-4. Get as the output of.

The saturation determination means 26 determines whether or not the output of the proximity sensor 8 is saturated (step S002). For example, a saturation flag is provided for each proximity sensor 8, and the saturation determination means 26 outputs the output of any of the four proximity sensors 8-1 to 8-4 in the light emitting state of the light emitting unit according to the specifications of the proximity sensor 8. When the given upper limit value is reached, the proximity sensor 8 is determined to be in the saturated state, and the saturation flag of the proximity sensor 8 is set to the on state.

If the saturation flag set to the ON state does not exist in the saturation determination S002 (when “No” in step S003), the initialization process of the values of various parameters including the reference value of the proximity sensor 8 is performed (the process of initializing the values of various parameters including the reference value of the proximity sensor 8). Step S004). On the other hand, if the saturation flag in the on state exists (in the case of "Yes" in step S003), if initialization is performed in the saturation state, an abnormal value may be set in the reference value or the like of the proximity sensor 8. Since there is a property, the process returns to step S001, and the processes of steps S001 to S003 are repeated until the saturation state is resolved.

In the initialization process S004, the reference value acquisition means 24 initially sets the reference value of the output of the proximity sensor 8. The reference value is the total value of the outputs of the plurality of proximity sensors 8-1 to 8-4 when the plan is not abnormal. This reference value is a value for removing fluctuations in the output of the entire proximity sensor 8 when determining proximity abnormality, and by removing the fluctuations, false alarms can be suppressed.

As described above, the output of each proximity sensor 8 is obtained as a value obtained by integrating the difference value of the amount of infrared rays received by the light receiving unit when the light emitting unit emits light and when the light emitting unit does not emit light over a predetermined time. The total output is calculated to obtain the total value of the outputs of the plurality of proximity sensors 8.

The reference value acquisition means 24 can also calculate a reference value regarding the total output of the plurality of proximity sensors 8 based on one output of the proximity sensor 8, but in the present embodiment, the reference value is defined as a plan abnormality. Calculate the average value of the total output during the undetermined period. By using the average value, it is possible to reduce the influence of temporary noise and the like.

Specifically, when it is confirmed in step S003 that the saturation flags of all the proximity sensors 8 are in the off state, it is assumed that no plan abnormality has occurred, and the control unit 12 indicates the presence or absence of the plan abnormality flag. Is set to the off state. Then, the reference value acquisition means 24 calculates the average value of the total values of the above-mentioned outputs based on the outputs of the proximity sensor 8 obtained periodically and repeatedly within a predetermined period, and sets the reference value.

Further, the reference value acquisition means 24 acquires initial values for the offset value and the IR illuminance reference value with respect to the output of each proximity sensor 8. The offset value of the proximity sensor 8 is basically given by the output of the proximity sensor 8 in the absence of a nearby object. As described above, the output is an integral value of the difference between the light receiving unit output in the light emitting state and the light receiving unit output in the non-light emitting state of the light emitting unit. For example, there may be a difference in the transmission efficiency of the optical conduit for each proximity sensor 8, and the offset value is set for each proximity sensor 8 in order to correct or eliminate the influence of the difference. In the present embodiment, in order to reduce the influence of the variation in the output, the output of the proximity sensor 8 is repeatedly acquired within a predetermined period, the average value thereof is calculated, and this is used as the offset value. In the initialization process S004, the average value in a predetermined period before the start of operation of the surveillance camera device 1 is obtained and used as the initial value of the offset value. The IR illuminance reference value is a value used when determining an ambient light abnormality, and is determined based on the IR illuminance value. Specifically, similarly to the offset value described above, the average value of the IR illuminance values in a predetermined period before the start of operation of the surveillance camera device 1 is calculated and used as the initial value of the IR illuminance reference value.

Further, in the initialization process S004, the control unit 12 sets, for example, the number of proximity abnormality determinations used for the plan abnormality determination to 0, which is an initial value, and sets the illumination flag to the current illumination state of the IR illumination unit 4. In addition, various state values used in the processing described later are also set as initial values. For example, the IR illumination change flag and the ambient light abnormality flag are set to the off state.

After the initialization process S004, the surveillance camera device 1 monitors the image of the monitored space while detecting the plan abnormality. During image monitoring, the control unit 12 performs a process of updating the reference value of the output of the proximity sensor 8 by the reference value acquisition means 24 (step S005), and similarly to step S001, the illuminance sensor 6 and the proximity sensor 8 Acquire the measured value (step S006).

The control unit 12 uses the acquired measured value to perform an environment determination process by the environment determination means 22 (step S007). In the environment determination process, it is determined whether or not the state of the IR lighting unit 4 has changed, and when the current state of the IR lighting unit 4 changes from the latest state, the IR lighting change flag is turned on and changed. If not, the flag is set to off. Further, in the environment determination process, it is determined whether or not the infrared light component contained in the ambient light becomes ambient light with respect to the proximity sensor 8. When it is determined that there is infrared light that becomes ambient light, the ambient light abnormality flag is set to the ON state.

In addition, the control unit 12 determines whether the proximity sensor 8 is saturated by the saturation determination means 26 (step S008). The determination is performed in the same manner as in step S002, and if any of the proximity sensors 8 is saturated, the saturation flag of the proximity sensor 8 is set to the ON state.

When none of the IR illumination change flag, the ambient light abnormality flag, and the saturation flag is turned on in the environment determination process S007 and the saturation determination process S008 (when "No" in steps S009 to S011), the control unit 12 performs a plan abnormality determination process by the plan abnormality determination means 28 (step S012). If the plan error flag is maintained in the off state in the process (in the case of "No" in step S013), the control unit 12 returns the process to step S005 and performs the process after the initialization process S004. repeat.

On the other hand, when the plan abnormality flag is set to the ON state (when “Yes” in step S013), the control unit 12 transmits an abnormality report to the monitoring center or the like via the communication unit 14, and the plan abnormality is detected. This is notified externally (step S014). In this case, the control unit 12 waits for the elapse of a predetermined time set in consideration of the time required for the response / response of the monitoring center or the like (step S015), then returns to step S001, and includes the initialization process S004. Repeat the process.

If the IR illumination change flag is on (“Yes” in step S009), the day / night mode is switched, that is, the day mode is switched to the night mode, or the night mode is switched to the day mode. Is performed, the control unit 12 returns to step S001 and repeats the process including the initialization process S004. Therefore, in this case, the reference value related to the total output of the proximity sensor 8 is updated in the initialization process S004 or the reference value update process S005.

Even when the ambient light abnormality flag is in the ON state (in the case of “Yes” in step S010), the process returns to step S001 and the process is repeated in the same manner. Therefore, also in this case, the reference value related to the total output of the proximity sensor 8 is updated in the initialization process S004 or the reference value update process S005.

On the other hand, if the saturation flag is in the ON state (in the case of "Yes" in step S011), the control unit 12 returns to step S006. That is, since the reference value of the proximity sensor 8 may not be set appropriately in the saturated state, the process of steps S006 to S011 is basically repeated without performing the reference value updating process S005. ..

FIG. 3 is a schematic flow chart of a reference value update process (step S005 in FIG. 2) of the output of the proximity sensor 8 by the reference value acquisition means 24.

The reference value acquisition means 24 sequentially inputs data used for calculating the reference value to a buffer memory of a predetermined size prepared for the reference value update process based on the outputs obtained from the illuminance sensor 6 and the proximity sensor 8 at predetermined time intervals. Memorize and accumulate. When the amount of stored data reaches the upper limit of the capacity of the buffer memory, the oldest data is deleted in order and new data is stored.

Specifically, in the reference value update process S005, when a new output value is obtained from the illuminance sensor 6 and the proximity sensor 8, data based on the new output value is added to the buffer memory (step S101), and the reference value update count is incremented. (Step S102). Here, the data stored in the buffer memory includes the output values of each of the four proximity sensors 8 and their total values, and the IR illuminance value obtained from the illuminance sensor 6. The reference value update counter is initially set to 0 when the surveillance camera device 1 is started, for example.

While the reference value update count is less than the predetermined update threshold value, the update of the reference value is suspended, and the process proceeds to step S006 of FIG. 2 (when “No” in step S103). Here, the update threshold can be set by the user based on a desired time interval for updating the reference value.

When the reference value update count reaches the update threshold value (when "Yes" in step S103), when the reference value update flag is on (when "Yes" in step S104), the reference value is set. It is updated (step S105). Here, the reference value update flag is for suppressing the update of the reference value when there is a possibility that a plan abnormality has occurred, and when the flag is in the off state (in step S104, " In the case of "No"), the reference value update process S105 is not performed.

In the reference value update process S105, the output reference value of the entire proximity sensor 8, the offset value of the output of each proximity sensor 8, and the IR illuminance reference value are updated. The reference value of the entire proximity sensor 8 is a reference value related to the total output of the plurality of proximity sensors 8-1 to 8-4 as described in the initialization process S004. In the update process S105, the reference value update flag is in the ON state, and the proximity sensor 8 can obtain an output in a state in which the plan is not abnormal. Therefore, in the update process S105, the reference value acquisition means 24 obtains the average value of the total output of the proximity sensor 8 in a period in which the plan is not abnormal, and updates the reference value of the output of the proximity sensor 8 with the average value. In the present embodiment, as described above, the output of the proximity sensor 8 is obtained as an integral value within a predetermined time of a difference value obtained by subtracting the amount of infrared rays received when the light emitting unit emits light and the amount of infrared rays received when not emitting light. Therefore, the total output of the proximity sensors 8 is obtained by the total of the output values of the proximity sensors 8.

Further, the reference value acquisition means 24 obtains and updates the offset value of the output of the proximity sensor 8 and the IR illuminance reference value in the same manner as in the initialization process S004.

As described above, if the reference value update flag is on, the update process S105 is executed, while if it is off, the update process S105 is not executed, but in either case, the reference value update count is cleared (step S106). ). That is, when the reference value update count reaches the update threshold value (in the case of “Yes” in step S103), the reference value acquisition means 24 updates the reference value regardless of whether or not the reference value update process S105 is executed. The count is reset to 0 and the process proceeds to step S006 of FIG.

FIG. 4 is a schematic flow chart of the environment determination process (step S007 in FIG. 2) by the environment determination means 22. In the environment determination process, it is determined whether or not the illumination state of the IR illumination unit 4 has changed (steps S201 to S204), and whether the infrared light component contained in the ambient light becomes ambient light with respect to the proximity sensor 8 (step). S205 to S206) are performed.

In determining whether or not there is a change in the lighting state, the environment determination means 22 acquires the current lighting state of the IR lighting unit 4 (step S201). The lighting state is switched by the D / N switching determination means 20, and in the day mode, the IR illumination unit 4 is in the non-light emitting state, and in the night mode, it is in the light emitting state. As will be described later, this switching is performed based on the output of the illuminance sensor 6, and if the illuminance value of visible light is equal to or more than a predetermined threshold value, the day mode is set, and if it is less than the predetermined threshold value, the night mode is set.

When the acquired current lighting state is different from the lighting state at the time of the previous processing (when “Yes” in step S202), the environment determination means 22 sets the IR lighting change flag to the on state (step S203). .. On the other hand, if the current lighting state of the IR lighting unit 4 has not changed from the lighting state at the time of the previous processing (when “No” in step S202), step S203 is skipped and the IR lighting change flag is initialized. It is kept in the off state set in S004.

When the above-mentioned processing is performed, the environment determination means 22 saves the current lighting state of the IR lighting unit 4 as the lighting state at the time of the previous processing for the next processing (step S204), and then shifts to the disturbance light determination processing. ..

In the disturbance light determination process, the environment determination means 22 compares the absolute value of the difference between the IR illuminance value and the IR illuminance reference value with a predetermined disturbance light threshold value, and if the difference is equal to or greater than the threshold value (in step S205). (In the case of "Yes"), the ambient light anomaly flag is set to the on state (step S206) assuming that the infrared light component contained in the ambient light becomes ambient light in the proximity abnormality determination, and the process is performed in step S008 of FIG. Proceed. On the other hand, if it is less than the threshold value (in the case of "No" in step S205), step S206 is skipped, and the ambient light abnormality flag is processed in step S008 of FIG. 2 while remaining in the off state set in the initialization process S004. Proceeds.

As described above, when the ambient light abnormality flag is turned on, the process is returned from step S010 to step S001 in the flow diagram of FIG. 2, and the reference value of the output of the proximity sensor 8 is updated. That is, if the amount of infrared light component contained in the illumination light in the monitored space is small, the influence of the fluctuation is small and it is difficult for the proximity sensor 8 to become ambient light, whereas the amount of infrared light component contained in the illumination light is large. , The influence of the fluctuation becomes large, and it is easy to cause disturbance light to the proximity sensor 8. Therefore, when the infrared light component contained in the ambient light is less than the threshold value, the disturbance light abnormality flag is turned off and the update of the reference value of the output of the proximity sensor 8 is omitted, whereas the infrared light component is equal to or higher than the threshold value. In the case of, the disturbance light abnormality flag is turned on and the reference value of the output of the proximity sensor 8 is updated to improve the reliability of the proximity abnormality detection by the proximity sensor 8.

FIG. 5 is a schematic flow chart of the plan abnormality determination process (step S012 in FIG. 2) by the plan abnormality determination means 28. The plan abnormality determination means 28 sets the total output of the plurality of proximity sensors 8 to be equal to or higher than a predetermined first threshold value as the first determination criterion, and is set lower than the first threshold value among the plurality of proximity sensors 8. The second determination criterion is that the number of those having an output of the second threshold value or more is a predetermined number or more. The output of the proximity sensor 8 is increased in the plan that obstructs the field of view of the image pickup unit 2. The first criterion determines this increase in output. On the other hand, the increase in the output may occur even when a part of the field of view of the imaging unit 2 is obstructed by insects, raindrops, or the like. In this regard, if the output of the proximity sensor 8 is increased at a plurality of locations near the imaging unit 2, it is presumed that the wide field of view is obstructed, and false alarm events related to the scheme such as insects and raindrops are eliminated. It is possible to do. The second determination criterion is provided from this viewpoint, and the scheme abnormality determining means 28 determines that the scheme is abnormal based on satisfying not only the first determination criterion but also the second determination criterion.

First, the plan abnormality determination means 28 calculates the total value of the outputs of the proximity sensors 8-1 to 8-4, and determines whether or not the total value satisfies the first determination criterion (step S301). At that time, in the present embodiment, the reference value of the entire proximity sensor 8 obtained in step S105 is taken into consideration. Specifically, the absolute value of the difference between the total value of the outputs of the proximity sensors 8-1 to 8-4 and the reference value is compared with a preset first threshold value.

When the absolute value of the difference between the total value of the outputs of the proximity sensor 8 and the reference value is equal to or greater than the first threshold value (when “Yes” in step S301), the plan abnormality determining means 28 further sets the second determination criterion. It is determined whether or not the condition is satisfied (step S302). In the present embodiment, the number of proximity sensors 8 having an output equal to or higher than the second threshold value is set to 4. That is, the second determination criterion is that all four proximity sensors 8 have an output equal to or higher than the second threshold value.

Further, when comparing the output of the proximity sensor 8 with the second threshold value in the second determination criterion, in the present embodiment, the offset value of the output of the proximity sensor 8 obtained in step S105 is taken into consideration. Specifically, the result of subtracting the offset value of the proximity sensor 8 from the output of the proximity sensor 8 is compared with a preset second threshold value. The second threshold value can be set for each proximity sensor 8 in consideration of the fact that there is a deviation in the output between the plurality of proximity sensors 8, but the offset value for each proximity sensor 8 is set as in the present embodiment. When the subtracted output is used, the second threshold value can be shared by the plurality of proximity sensors 8.

When the value obtained by subtracting the offset value from the output of the proximity sensor 8 is equal to or greater than the second threshold value (in the case of “Yes” in step S302), it means that the first and second determination criteria are satisfied. In this case, there is a possibility that the visual field of the imaging unit 2 is obstructed, and there is a possibility that a plan abnormality has occurred. However, the plan abnormality determining means 28 does not immediately determine that the plan is abnormal, and provisionally It is treated as a state in which the proximity sensor 8 detects an abnormality (proximity abnormality state), and when the proximity abnormality state continues for a predetermined period, it is determined that the plan is abnormal. The number of proximity abnormality determinations is used to measure the duration of the proximity abnormality state, and the plan abnormality determination means 28 increments the number of proximity abnormality determinations when the first and second determination criteria are satisfied (step S303). ..

When the number of proximity abnormality determinations 28 or more (in the case of “Yes” in step S304), the plan abnormality determination means 28 sets the reference value update flag to the off state (step S305). .. As a result, the update process of the reference value (S105 in FIG. 2) during the proximity abnormality detection is suppressed. The plan abnormality pre-threshold value can be set to 1, for example.

Further, when the number of proximity abnormality determinations is equal to or greater than the plan abnormality threshold value (when “Yes” in step S306), the plan abnormality determination means 28 sets the plan abnormality flag to the ON state (step S307), and the process is shown. Proceed to step S013 of 2.

On the other hand, when the first determination criterion or the second determination criterion is not satisfied (when "No" in step S301 or S302), the plan abnormality determination means 28 resets the number of proximity abnormality determinations to 0 (step S308). ), The process proceeds to step S013 of FIG. By the way, in this case, the plan abnormality flag is kept in the default off state.

When the number of proximity abnormality determinations is less than the plan abnormality pre-threshold value (when “No” in step S304), the plan abnormality determination means 28 performs processing while maintaining the reference value update flag in the initially set ON state. The process proceeds to step S013 of FIG. By the way, in this case, the plan abnormality flag is in the default off state.

When the number of proximity abnormality determinations is less than the plot abnormality threshold value (when “No” in step S306), the plot abnormality determination means 28 performs the process while maintaining the plot abnormality flag in the initially set off state. Step S013 of. Incidentally, in this case, the reference value update flag is set to the off state in step S305.

FIG. 6 is a schematic flow chart of the day / night switching process by the D / N switching determining means 20. When the surveillance camera device 1 is activated, the D / N switching determination means 20 continuously executes the process shown in FIG. Here, in order to simplify the flow chart, it is assumed that the day mode is set at the start of the process, that is, at the start of the surveillance camera device 1, but if the night mode is set at the start, the process starts from step S404. Processing is started.

As described above, the D / N switching determination means 20 sets the day mode when the illuminance value of visible light is equal to or more than a predetermined threshold value, and sets the night mode when the illuminance value is less than the threshold value, based on the output of the illuminance sensor 6. The visible light illuminance value can be obtained by subtracting the IR illuminance value from the CLEAR illuminance value.

In the day mode, the D / N switching determination means 20 repeats the determination process S401 for determining whether the visible light illuminance value is below the predetermined night mode transition illuminance threshold (when “No” in step S401), and is visible. When the light illuminance value falls below the threshold value (in the case of "Yes" in step S401), the timer count-up is started, and the elapsed time from that state exceeds the predetermined night mode transition time threshold value. The threshold determination process S402 is performed. The D / N switching determination means 20 performs a loop process in which steps S401 and S402 are repeated (in the case of "No" in step S402), and when the elapsed time exceeds the threshold value (in the case of "Yes" in step S402), it is night. Move to mode. Specifically, the D / N switching determination means 20 removes the IR cut filter from the optical system of the image pickup unit 2 and turns on the IR illumination unit 4.

On the other hand, in the day mode, the D / N switching determination means 20 repeats the determination process S404 for determining whether the visible light illuminance value exceeds the predetermined day mode transition illuminance threshold value (when “No” in step S404). When the visible light illuminance value exceeds the threshold value (in the case of "Yes" in step S404), the timer count-up is started, and the elapsed time from the state is set to the predetermined day mode transition time threshold value. The determination process S405 of whether or not the value is exceeded is performed. The D / N switching determination means 20 performs a loop process of repeating steps S404 and S405 (when “No” in step S405), and when the elapsed time exceeds the threshold value (when “Yes” in step S405), the day Move to mode. Specifically, the D / N switching determination means 20 inserts the IR cut filter into the optical system of the image pickup unit 2 and turns off the IR illumination unit 4.

Here, by making the elapsed time exceeding the threshold value a requirement for mode switching in steps S402 and S405 described above, it is possible to make mode switching less likely to occur due to a temporary change in illuminance. Further, the night mode transition illuminance threshold and the day mode transition illuminance threshold can be set to different values. Specifically, by setting the night mode transition illuminance threshold value lower than the day mode transition illuminance threshold value, it is possible to give the mode switching a histellisis characteristic. That is, for example, when the illuminance falls below the night mode transition illuminance threshold and the day mode is switched to the night mode, the day mode is not returned even if the illuminance fluctuates and exceeds the night mode transition illuminance threshold. In this way, it is possible to prevent frequent mode switching due to small fluctuations in illuminance, and to ensure mode stability.

In addition, when the visible light illuminance value becomes equal to or higher than the threshold value after the timer count-up starts in the day mode (when "No" in step S401), or after the timer count-up starts in the night mode, the visible light illuminance value. Is equal to or less than the threshold value (in the case of "No" in step S404), for example, the timer is reset.

1 Surveillance camera device, 2 Imaging unit, 4 IR lighting unit, 6 Illuminance sensor, 8 Proximity sensor, 10 IR lighting control unit, 12 Control unit, 14 Communication unit, 16 Storage unit, 20 D / N switching determination means, 22 Environment Judgment means, 24 reference value acquisition means, 26 saturation determination means, 28 plan abnormality determination means.

Claims (7)

Imaging unit and
A plurality of proximity sensors arranged in the vicinity of the imaging unit and
It has a plan abnormality determining means for determining a plan abnormality that obstructs the visual field of the imaging unit based on the outputs of the plurality of proximity sensors.
The plan abnormality determination means is
The first criterion is that the total output of the plurality of proximity sensors is equal to or greater than a predetermined first threshold value.
The second determination criterion is that the number of the proximity sensors whose output is lower than the first threshold value and equal to or higher than a predetermined second threshold value is a predetermined number or more.
Determining that the plan is abnormal based on satisfying the first and second determination criteria.
A surveillance camera device characterized by. The proximity sensor is an infrared type and has a light emitting unit that emits infrared light and a light receiving unit that receives infrared light.
The plan abnormality determining means acquires, as the output of the proximity sensor, an integral value of the difference value of the infrared light receiving amount of the light receiving unit between the light emitting unit and the non-light emitting unit at a predetermined time.
The surveillance camera device according to claim 1. The surveillance camera device according to claim 1 or 2, wherein the second determination criterion is that the outputs of all the plurality of proximity sensors are equal to or higher than the second threshold value. As a reference value regarding the total output of the plurality of proximity sensors, there is a reference value acquisition means for obtaining the average value of the total output during a period in which the plan is not abnormal.
The first determination criterion is that the absolute value of the difference between the total output and the reference value is equal to or greater than the first threshold value.
The surveillance camera device according to any one of claims 1 to 3, wherein the surveillance camera device is characterized. It has a saturation determination means for determining that the output of the proximity sensor is saturated.
The reference value acquisition means updates the reference value at predetermined time intervals when the plurality of proximity sensors are not in the saturated state, and updates the reference value when any of the proximity sensors is in the saturated state. To stop,
The surveillance camera device according to claim 4. It has an illuminance sensor that measures the illuminance of infrared light components with respect to the ambient light in the imaging unit.
The reference value acquisition means updates the reference value when the illuminance is equal to or higher than a predetermined value.
The surveillance camera device according to claim 4 or 5. The surveillance camera according to claim 6, wherein the proximity sensor and the illuminance sensor are sensor elements integrally formed, and the output of the proximity sensor and the illuminance of the illuminance sensor are alternately output. Device.

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