JPH06266976A - Method and device for abnormal intruder detection - Google Patents

Abstract

PURPOSE:To exactly detect an abnormal intruder from among the intruders into an entrance forbidding area, and to intuitively judge the intruding place on a TV screen. CONSTITUTION:In a normal state that the intruder is absent, a switch 11 is turned on/off, and an original picture is stored in a picture memory 13. Afterwards, subtraction between the original picture stored in the picture memory 13 and a picture from an infrared ray camera 1 is operated by a subtracting circuit 15. A signal conversion circuit 16 outputs an ON signal when the output of the subtracting circuit 15 is more than a constant value, and a signal conversion circuit 17 searches the differentiated value of the output of the subtracting circuit 15, and outputs a pulse signal according to the change of more than the constant value. When the intruder is absent, the signal conversion circuits 16 and 17 output no signal. When the intruder is present, the signal conversion circuit 17 outputs one pulse signal when the intruder doesn't carry an infrared ray emitter, and the signal conversion circuit 17 outputs the pulse signal in a constant cycle when the intruder carries the infrared ray emitter. Thus, a discriminating circuit 18 detects the abnormal intruder.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for detecting an abnormal intruder in a restricted area such as an outdoor fuel storage tank.

[0002]

2. Description of the Related Art Conventionally, as a detection system for detecting an abnormal intruder in an off-limits area such as an outdoor fuel storage tank in a thermal power plant, an infrared ray is generally provided around the surveillance area to check whether light rays are blocked or not. Intruders are being detected.

In such an abnormal intruder detection system, it is very important for disaster prevention to detect only the abnormal intruders excluding the authorized persons such as patrols from the intruders entering the restricted area such as the outdoor fuel storage tank. is important.

[0004]

However, it is very difficult to discriminate the type of intruder by the conventional method of discriminating the intruder by blocking the infrared ray, and the monitoring range is the fuel oil tank yard. It is limited to the emission line of infrared rays stretched around the circumference of.

Further, since it is possible to monitor only the emission line of infrared rays, it is possible to avoid the line easily, and it is not possible to intuitively know the intrusion position on the TV (television) screen during detection.

The present invention has been made in view of the above circumstances, and it is possible to limit the detection to an abnormal intruder from among intruders entering the exclusion zone, and the intruding point is more intuitive on the TV screen. It is an object of the present invention to provide an abnormal intruder detection method and device that can be determined according to the above.

[0007]

A method for detecting an abnormal intruder according to the present invention detects an intruder based on a change in infrared intensity of an object to be monitored by monitoring an off-limit area with an infrared camera and at the same time permits an entry. It is characterized in that an abnormal intruder is discriminated from an authorized person by image processing on an infrared light emitting device that blinks at a predetermined cycle carried by a person.

Further, the abnormal intruder detection device according to the present invention is an infrared camera for monitoring a restricted area, an infrared light emitter blinking at a predetermined cycle carried by a person authorized to enter the restricted area, and the infrared ray. Storage means for storing the image signal of the normal time output from the camera as an original image signal,
ON if the original image signal stored in the storage means and the image signal output from the infrared camera are subtracted, and if the output signal of the subtraction means is a certain value or more.
First signal converting means for outputting a signal, second signal converting means for calculating a differential value of the output signal of the subtracting means, and outputting a pulse signal in response to a positive change of a certain value or more, the first and second signal converting means It is characterized by further comprising a discriminating means for discriminating an abnormal intruder based on the output signal of the signal converting means of No. 2.

[0009]

When there is no intruder in the off-limits area such as the fuel storage tank, the temperature distribution in the off-limit area does not change at an early cycle because only environmental changes occur.

When the image signal from the infrared camera is taken in at a constant cycle and the image signal of the camera taken in the normal state, that is, the original image signal is continuously subtracted between the images, the subtraction result in the state where the image does not change is zero ( The screen is all black). However, when there is an intruder, infrared energy emitted by the intruder appears as a change in the image. When the image subtraction between the image signal from the infrared camera and the original image signal in the normal state stored in the storage means is performed, only the image portion changed by the intruder appears as a difference.

Next, when the change cycle of the intensity of infrared rays indicated by the change point detected as an intruder and the blinking cycle of the infrared light emitting device of the permitter are the same, it is discriminated as the permitter, and otherwise the intruder is abnormal. Detect as.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a system configuration diagram showing an embodiment of the present invention, in which T is an outdoor fuel storage tank, and M is an intruder of the fuel storage tank T in a restricted area. In this case, the entry permitter is allowed to carry an infrared light emitting device that blinks at a period given as a password. Then, the infrared area of the fuel storage tank is photographed by the infrared camera 1, the photographed image is output to the infrared camera image display monitor television 2, and the infrared intensity of the object to be monitored is radiated.
The so-called temperature distribution is monitored.

The image photographed by the infrared camera 1 is sent to the signal processing device 3. The signal processing device 3 captures the image signal sent from the infrared camera 1 at a constant cycle, and continuously performs image-to-image subtraction with the camera image captured during normal operation, that is, the original image signal. When this subtraction between images is performed, the subtraction result is zero (the entire screen is black) in a state where there is no image change. However, if there is an intruder M, the infrared energy radiated by the intruder M appears as an image change. Therefore, only the image portion changed by the intruder due to the image-to-image subtraction is displayed as a difference, and the change period of the intensity of the infrared intensity indicated by the change point at this time is the same as the blinking period of the infrared light emitter of the authorized person. If the same, it is identified as an authorized person, and the others are identified as an abnormal intruder.

FIG. 2 is a block diagram showing details of the signal processing device 3. The image signal Va output from the infrared camera 1 is A / D via an analog / digital conversion input switch (hereinafter referred to as A / D input switch) 11.
It is input to the (analog / digital) conversion circuit 12, converted into a digital signal, and stored in the image memory 13. The image memory 13 is for storing the image signal taken in from the infrared camera 1 in the normal state as an original image signal. The original image signal stored in the image memory 13 is converted into an analog signal by the D / A conversion circuit 14, and is sent to the image signal subtraction circuit 15 as the original image signal Vb. The subtraction circuit 15 includes an infrared camera 1
The image signal Va from is input. The subtraction circuit 15 uses the image signal Va from the infrared camera 1 and the D / A conversion circuit 14.
Subtraction with the original image signal Vb input from
For example, the original image signal Vb is subtracted from the image signal Va, and the subtraction result is input to the first signal conversion circuit 16 and the second signal conversion circuit 17.

The first signal conversion circuit 16 includes a subtraction circuit 15
If the output of is above a certain value, the ON signal is judged
Output to. The second signal conversion circuit 17 includes a subtraction circuit 15
The differential value of the output signal is obtained, and a pulse signal having a constant width is output to the discriminating circuit 18 in response to a positive change of a predetermined value or more.
The determination circuit 18 is a circuit for determining the presence or absence of an intruder and outputting an alarm. The AND circuit 21 and the inverter 2
2, a timer 23, a flip-flop 24, the first
The output of the signal conversion circuit 16 is input to the AND circuit 21, and the output of the second signal conversion circuit 17 is input to the AND circuit 21 via the inverter 22. This AND circuit 2
The output of 1 is input to the set terminal S of the flip-flop 24 via the timer 23, and the output of the second signal conversion circuit 17 is input to the reset terminal R of the flip-flop 24. Then, the alarm lamp 25 is turned on by the output of the flip-flop 24.

Next, the operation of the above embodiment will be described. First,
In a normal state where there is no intruder in the off-limits area of the fuel storage tank T, the A / D input switch 11 is turned on once and then turned off, so that the image in the normal state photographed by the infrared camera 1 is stored in the image memory 13 To memorize.

That is, the image signal Va output from the infrared camera 1 is the A / D input switch 11 and the subtraction circuit 15.
Input, so turn on the A / D input switch 11 now.
If so, the image signal Va is transferred to the A / D conversion circuit 12
To the image memory 13 and digitized. Therefore, the image stored in the image memory 13 is sequentially updated. Then, the successively updated image signal of the image memory 13 is read by the D / A conversion circuit 14, converted into an analog signal, and sent to the subtraction circuit 15 as the original image signal Vb. The original image signal Vb passes through the A / D conversion circuit 12, the image memory 13, and the D / A conversion circuit 14, but is almost the same as the image signal Va output from the infrared camera 1. Therefore, the subtraction value in the subtraction circuit 15 becomes almost zero.

Next, when the A / D input switch 11 is switched from the ON state to the OFF state, the image signal input to the A / D conversion circuit 12 is lost, and the image memory 13 is in the state immediately before the A / D input switch 11 is turned off. The image signal will be retained. Since the D / A conversion circuit 14 converts the image signal stored in the image memory 13 into an analog signal and outputs the original image signal Vb, the original image signal Vb is held and is not changed. It becomes a fixed image. This fixed image is generated by turning on / off the A / D input switch 11 as described above.
Since it is stored by the FF, it can be arbitrarily determined. That is, an intruder M enters the restricted area of the fuel storage tank T.
In a normal state where there is no light, turn the A / D input switch 11 to O.
By turning off N and OFF, the image in the normal state of the fuel storage tank T and the off-limits area shown in FIG. 3A can be stored in the image memory 13.

On the other hand, the A / D input switch 11 is turned off.
Then, the subtraction circuit 15 receives the normal fixed image stored in the image memory 13 and the real-time image captured by the infrared camera 1, and the subtraction between the two image signals is performed. A value proportional to the displacement amount between the fixed image and the current image is output to the first signal conversion circuit 16 and the second signal conversion circuit 17.

The first signal conversion circuit 16 includes a subtraction circuit 15
If the output of is above a certain value, an ON signal is output. Further, the second signal conversion circuit 17 obtains a differential value of the output of the subtraction circuit 15 and outputs a pulse signal having a constant width with respect to a positive change of a predetermined value or more. Therefore, when there is no intruder M, there is no output in any of the signal conversion circuits 16 and 17, and the determination circuit 18 determines that there is no intruder and outputs the alarm lamp 2.
5 is not turned on.

When someone enters the off-limits area of the fuel storage tank T, the infrared camera 1 causes the infrared camera 1 shown in FIG.
The intruder M is photographed together with the fuel storage tank T as shown in FIG. At this time, the subtraction circuit 15 performs subtraction between the image signals, and as the image signal of the calculation result, only the changed image is obtained as shown in FIG.

FIG. 3D is a locus in the case where the result of subtraction between the image signals of the subtraction circuit 15 obtained when the intruder M moves from the left side to the right side of the image is shown in the same image. When converted into an electric signal proportional to the area or intensity (infrared intensity), it becomes as shown in FIG.
However, when the intruder M carries an infrared light emitter which is a permitter, the electric signal has a signal waveform in which a pulse signal is superimposed as shown in FIG. Output signals of the first signal conversion circuit 16 and the second signal conversion circuit 17 for FIGS. 3 (e) and 3 (f) are shown in FIGS. 3 (g) and 3 (h). Figure 3
The output of the first signal conversion circuit 16 shown in (g) and (h) is at a high level (ON) due to the image change amount by the intruder M in any case.

On the other hand, the output of the second signal conversion circuit 17 is
It changes depending on whether or not an infrared light emitter is carried. Intruder M
3 does not carry an infrared light emitter, the second signal conversion circuit 17 causes the intruder M to make a first signal at the rising edge of the output signal of the subtraction circuit 15 as shown in FIG.
It is at a low level (OFF) except that a pulse signal is generated in the differential value detected as the difference for the first time. The flip-flop 24 is reset by this pulse signal, but after that, the output of the second signal conversion circuit 17 is held at the low level, so that the output of the inverter 22 in the determination circuit 18 becomes the high level. As a result, the logical condition of the AND circuit 21 is satisfied, and the output of the AND circuit 21 becomes high level. When the high level output of the AND circuit 21 continues for a set time or longer, the timer 23 shown in FIG. 3 (i) is activated, the flip-flop 24 is set, and the alarm lamp 25 is set.
Lights up. Thereby, the abnormal intruder M can be detected.

However, if the intruder M is an authorized person and carries an infrared light emitting device, the output signal of the subtraction circuit 15 is as shown in FIG.
Since a pulse signal having a constant cycle is included as shown in (f), the pulse signal has a constant cycle as shown in FIG. 3 (h) from the second signal conversion circuit 17 corresponding to this pulse signal. Is output. Each time this pulse signal is output, the output of the inverter 22 becomes low level, and the AND circuit 21
Close the gate. As a result, the timer 23 is reset each time the pulse signal is output, so that it does not operate and the alarm lamp 25 does not light.

As described above, the intruder M can detect only the abnormal intruder M by carrying the infrared light emitting device which blinks at the period given as the password. In this case, even if the abnormal intruder M carries some kind of light emitter, the light emission does not satisfy the predetermined condition, so that the discrimination circuit 18 can detect the abnormal intruder M.

[0027]

As described above in detail, according to the present invention, it is possible to discriminate between an intruder authorized to intrude such as a patrol member and an abnormal intruder, which could not be discriminated in the past, and reduce false alarms during patrol. The reliability can be remarkably improved.

[Brief description of drawings]

FIG. 1 is a system configuration diagram according to an embodiment of the present invention.

FIG. 2 is a block diagram showing details of a signal processing device in the embodiment.

FIG. 3 is an operation explanatory diagram of the embodiment.

[Explanation of symbols]

 T ... Fuel tank M ... Intruder M 1 ... Infrared camera 2 ... Monitor TV 3 ... Signal processing device 11 ... A / D input switch 12 ... A / D conversion circuit 13 ... Image memory 14 ... D / A conversion circuit 15 ... Subtraction Circuit 16 ... First signal conversion circuit 17 ... Second signal conversion circuit 18 ... Discrimination circuit 21 ... AND circuit 22 ... Inverter 23 ... Timer 24 ... Flip-flop 25 ... Warning lamp

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ryoichi Sasaki 5-717, Fukahori-cho, Nagasaki-shi, Nagasaki 1 Choryo Engineering Co., Ltd.

Claims (2)

[Claims] 1. An infrared camera monitors an off-limits area to detect an intruder based on a change in the intensity of infrared rays radiated from an object to be monitored, and image processing for an infrared light emitter blinking at a predetermined cycle carried by an off-limits person. An abnormal intruder detection method characterized by distinguishing an abnormal intruder from an authorized person by means of. 2. An infrared camera for monitoring a closed area, an infrared light emitter blinking at a predetermined cycle carried by a person who is permitted to enter the closed area, and an image signal in a normal state output from the infrared camera. Storage means for storing as an original image signal, subtraction means for performing a subtraction between the original image signal stored in the storage means and the image signal output from the infrared camera, and an output signal of the subtraction means is a certain value or more. If there is, first signal converting means for outputting an ON signal, second signal converting means for calculating a differential value of the output signal of the subtracting means, and outputting a pulse signal in response to a positive change above a certain value, the second signal converting means. An abnormal intruder detection device comprising: a determination unit that determines an abnormal intruder based on the output signals of the first and second signal conversion units.