JPS62825A - Scanning type infrared detecting device - Google Patents

Abstract

PURPOSE:To perform secure detection without any dead area by storing the output level of an infrared sensor in a waveform storage means as a normal level waveform throughout one scan on a scanning pattern. CONSTITUTION:When a positive-directional rotary driving signal sent out of a microcomputer 17 is sent to a stepping motor driving circuit 22, a stepping motor 13 rotates in a positive direction by the specific angle of rotation. Then when the motor 13, i.e. a sensor body 12 rotates by 2 deg. at every time, a digital detection signal from an A/D converter 21 is fetched and stored in the Nth memory address of a memory circuit 24. Thus, the digital detection signal is fetched at every time a main body 12 rotates by 2 deg.. When the main body 12 rotates by 360 deg., the microcomputer 17 sends out a reverse rotation signal next and when the main body 12 reverses by 2 deg., the digital detection signal is fetched. Then, the signal level stored in the Nth memory space is read out by the microcomputer 17 and compared with a currently fetched detection signal level, thereby sending out an alarm driving signal to an alarm device 23 when those signal levels coincide with each other.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a scanning infrared detection device that detects an intruder using infrared rays.

[Technical background of the invention]

Conventionally, this type of device has been used in a wide variety of fields because it is ideal for automating the entire system, saving labor, and preventing crime. As a means for detecting infrared rays, a pyroelectric infrared sensor (hereinafter referred to as a pyroelectric sensor) is used, which utilizes the pyroelectric effect in which a ferroelectric substance is polarized due to a temperature change and generates an electric charge. This pyroelectric sensor is composed of a ceramic material based on PZT, TGS, etc. that has a pyroelectric effect and a blackened film that has a heat absorption function.

Therefore, in the detection operation, a multi-mirror is provided close to the pyroelectric sensor, and the infrared rays in each direction collected by the multi-mirror are guided to the non-electroelectric sensor, and from the pyroelectric sensor, the infrared I! l
Outputs an electrical detection signal according to II. Then, this detection signal is sent to an amplification/comparison circuit and compared with a reference infrared ray amount signal for intruder detection, and when the signal level exceeds this signal level, an alarm for intruder detection is issued.

(Problems with the Background Art) However, since the above-mentioned device uses a multi-mirror as a condensing means for infrared rays, a so-called blind spot occurs in the intruder detection area. In other words, since the multi-mirror has a configuration in which mirrors placed in all directions are combined, in reality there is inevitably a blind spot 2 between the detection areas 1 of each mirror, as shown in Figure 8. I can do it. As a result, intruders cannot be detected in areas where it is absolutely necessary.
Therefore, there is a need for a detection device that does not have blind spots.

[Purpose of the invention]

The present invention has been made based on the above-mentioned circumstances, and its object is to provide a highly reliable scanning infrared detection device that can perform detection operations reliably without creating blind spots.

[Summary of the invention]

The present invention stores the output level of the infrared sensor over one scan of the scanning pattern by the scanning means as a normal level waveform in the waveform storage means, and combines the stored normal level waveform and the output signal level of the infrared sensor in the scanning state. This is a scanning type infrared detection device that compares the levels every time a predetermined scanning distance is traveled and notifies the presence of an infrared emitting object if the two levels do not match. [Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of a scanning infrared detection device, and FIG. 2 is a functional block diagram. 10 is an installation case,
This case 1o houses a control circuit 11 for intruder detection and a stepping motor 13 that drives the sensor main body 12 in a predetermined scanning pattern, for example, in the directions of arrows (a) and (b). The sensor body 12 includes an infrared condensing mirror 14 with unidirectionality that condenses infrared rays.
A pyroelectric sensor 15 receives the infrared light collected by the mirror 14 and converts it into an electrical detection signal according to the amount of infrared light, and a pyroelectric sensor 15 amplifies the detection signal output from the pyroelectric sensor 15. An amplifier circuit 16 that sends out signals to the control circuit 11 is housed therein. Now, the configuration of the control circuit 11 is such that the microcomputer 17 is connected to an A/
A D converter (analog-digital converter) 21, a stepping motor drive circuit 22, an alarm device 23, and a memory circuit 24 are connected.

By the way, the microcomputer 17 has various functions as shown in FIG. 3, and issues various commands according to the intruder detection flowcharts shown in FIGS. 4 and 5. Specifically, from the pyroelectric sensor 15 after one scan according to the scanning pattern of the pyroelectric sensor 15, that is, after the sensor body 12 has rotated 360 degrees in the direction of arrow (a) and further rotated 360 degrees in the direction of arrow (b). A waveform record WL function 17-1 stores all output detection signal levels as a normal level waveform in the memory circuit 24, and a pyroelectric sensor is activated every time the pyroelectric sensor 15 travels a predetermined scanning distance, that is, every 2° rotation of the sensor body 12. Comparison 1 function 17-2 receives the detection signal output from 15 and compares this detection signal level with the signal level corresponding to the scanning position of the pyroelectric sensor 15 in the normal level waveform, and the comparison function 17-2. As a result, if the two levels do not match, the alarm device 23 sends an alarm drive signal to determine that an infrared emitting object, that is, an intruder has been detected, and issue an alarm.
The alarm signal sending function 17-3 is provided. In addition, in this device, the sensor main body 12 is rotated 36 times in the forward and reverse directions.
One cycle is defined as each rotation of 0°.

Next, the operation of the apparatus configured as described above will be explained according to a flowchart for detecting an intruder. When the microcomputer 17 issues a rotational drive signal in the forward direction, that is, the (A) direction, this signal is sent to the stepping motor drive circuit 22 via the I10 port 19. As a result, the stepping motor 13 rotates in the forward direction by a predetermined rotation angle.

Immediately after issuing this rotation drive signal, the microcomputer 17 sets the memory address N to "1". Then, it is determined whether the stepping motor 13 has rotated 2 degrees, that is, the sensor body 12 has rotated 2 degrees, and if it has rotated 2 degrees, the A/
The digital detection signal from the D converter 21 is taken in, and this digital detection signal is stored in the memory space of the memory circuit 24 at the Nth memory address. When this storage operation is completed, the memory address is changed to rN+IJ. Then, 2
When the sensor main body 12 rotates, that is, rotates by 4 degrees as a whole, it takes in the digital detection signal again and transfers this digital detection signal to the memory address N+1 of the memory circuit 24.
memory space. In this manner, a digital detection signal is captured every 2 degrees until the sensor main body 12 rotates 360 degrees and is stored in the memory circuit 24. Then, when the microcomputer 17 determines that it has rotated 360° in the forward direction, it sends out a rotation drive signal in the reverse direction, that is, in the (b) direction. Then, the sensor body 12 rotates in the opposite direction. Then, each time the stepping motor 13 rotates by 2 degrees, a digital detection signal is taken in again, and each digital detection signal is stored in the memory circuit 24. When the digital detection signal is stored in the memory circuit 24 every 2° rotation during 360° rotation in the forward and reverse directions as described above, this becomes the normal level waveform P in which there is no intruder as shown in FIG. is stored as.

Now, when the sensor body 12 rotates 360° in the opposite direction and obtains the normal level waveform P@, the microcomputer 17
again sends out a rotation drive signal in the positive direction. When this rotation drive signal is issued, the stepping motor 13 rotates in the forward direction by a predetermined rotation angle in the same manner as in the above operation. Immediately after issuing this rotation drive signal, the microcomputer 17 sets the memory address N to "1" again. Then, it is determined whether the sensor main body 12 has rotated by 2 degrees, and if it has rotated by 2 degrees, a digital detection signal from the A/D converter 21 is taken in. Therefore, the microcomputer 17 reads the signal level of the normal level waveform P stored in the memory space at the Nth memory address by the above operation,
This signal level is compared with the digital detection signal level just captured. As a result of this comparison, if the signal levels match, it is determined that there is no other device that emits infrared rays, and the memory address is changed to rN+IJ. Then, when the sensor main body 12 further rotates by 2 degrees, the digital detection signal is taken in again, and this signal is compared with the signal level of the normal level waveform P stored in the memory space N+1. However, if the comparison result between the signal level of the normal level waveform P and the captured digital detection signal level does not match as shown in FIG. Send. Thus, the alarm device 23 issues an alarm indicating the presence of an intruder.

In this way, every time the sensor main body 12 rotates by 2 degrees, a digital detection signal is taken in to determine whether there is an intruder. Then, when the sensor body 12 rotates 360 degrees,
The microcomputer 17 then sends out a rotation drive signal for reverse rotation. Then, it is determined whether the sensor main body 12 has rotated 2 degrees in the opposite direction, and if it has rotated 2 degrees, the digital detection signal from the A/D converter 21 is taken in. Therefore, the microcomputer 17 reads out the signal level of the normal level waveform P stored in the Nth memory space by the above operation, and compares this signal level with the digital detection signal level just taken in. As a result of this comparison, if the respective signal levels do not match, the alarm drive signal 2 is sent to the alarm device@23.

In this way, in the above embodiment, one of the scanning patterns
The memory circuit 24 uses the detection signal level output from the pyroelectric sensor 15 over cycle scanning as a normal level waveform P.
This stored normal level waveform P is compared with the detection signal level of the pyroelectric sensor 15 in the scanning state every 2° rotation, and if the two signal levels do not match, it is determined that there is an intruder. Since the system is configured to issue an alarm, the intruder detection area Q can be the entire circumferential range with the pyroelectric sensor 12 as the center and the detectable distance as the radius, as shown in FIG. Therefore, it is not the case that an alarm is not issued even though there is an intruder. Furthermore, since a single mirror is used as the infrared condensing mirror 14, the detection distance can be increased and the detection range can be widened.

Note that the present invention is not limited to the above embodiment. In the above embodiment, a rotational scanning type detection device has been described, but the present invention can also be applied even if the scanning type is a linear type or a curved type. Specifically, for example, the present invention can be applied even when a straight or curved rail is provided on the ceiling and a sensor body containing a pyroelectric sensor is run on this rail. Alternatively, the normal level waveform may be constantly changed by storing one cycle of the detected signal waveform and determining the signal level detected most frequently.

[Effects of the Invention] As detailed above, according to the present invention, one of the scanning patterns
The output level of the infrared sensor over scanning is stored as a normal level waveform in the waveform storage means, and the stored normal level waveform and the output signal level of the infrared sensor in the scanning state are compared every time a predetermined scanning distance is traveled, and both levels are determined. Since the presence of an infrared emitting object is notified when the numbers do not match, it is possible to provide a highly reliable scanning infrared detection device that can perform a reliable detection operation without creating a blind spot.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an embodiment of a scanning infrared detection device according to the present invention, Fig. 2 is a functional block diagram of the inventive device, and Fig. 3 is a specific functional block diagram of a microcomputer. , FIG. 4 and FIG. 5 are flowcharts for detecting an intruder by the device of the present invention, FIG. 6 is a diagram showing the alarm output judgment of the device of the present invention, FIG. 7 is a diagram showing the detection area by the device of the present invention, and FIG. The figure is a diagram showing a detection area in a conventional device. 10... Installation case, 11... Control circuit, 12...
・Sensor body, 13...Stepping motor, 14・
...Infrared condensing mirror, 15...Pyroelectric mirror, 17.
... Microcomputer, 17-1... Waveform storage function, 17-2... Comparison function, 17-3... Alarm signal sending function, 22... Stepping motor drive circuit, 2
3...Alarm device, 24...Memory circuit. Applicant's Representative Patent Attorney Takehiko Suzue Figure 1 Figure 3 Figure 4 Figure 6 Figure 7 Figure 8

Claims (1)

[Claims] scanning means for scanning the infrared sensor according to a predetermined scanning pattern; and a waveform memory for storing the detection signal level of the infrared sensor over one scan according to the operation pattern of the infrared sensor as a normal level waveform without any infrared generation. and comparing means for capturing an output signal of the infrared sensor every time the infrared sensor travels a predetermined scanning distance and comparing the output signal level with a signal level corresponding to the scanning position of the infrared sensor in the normal level waveform; A scanning type infrared detection device comprising: a notification device for notifying the presence of the infrared emitting substance when the two levels do not match as a result of comparison by the comparison device.