JPS6041793B2 - Ultrasonic warning system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ultrasonic warning system for monitoring a predetermined security area by using ultrasonic waves, and particularly to detecting the presence or absence of an intruder within a predetermined security area. The present invention relates to a preferred ultrasonic warning system.

Conventionally, for example, ultrasonic waves are continuously emitted into a room, and when an intruder enters the room, the presence of the intruder is detected using the Doppler effect that occurs when the intruder moves. An ultrasonic warning device is used.

However, in principle, with this type of conventional device, there is an extremely high risk of false alarms being issued due to curtains swaying due to drafts, etc., so the circuitry must be complicated and expensive to prevent this kind of false alarms. Moreover, when the device is placed indoors, the detection sensitivity must be adjusted each time depending on the shape of the room, which has the disadvantage of requiring time and effort. Furthermore, with conventional devices, it is extremely difficult to use a predetermined outdoor area as a warning area, and therefore, there is also the disadvantage that it is only possible to carry out surveillance within a predetermined area that is physically demarcated, such as indoors. There is. The present invention has been made in order to eliminate the above-mentioned drawbacks of conventional devices, and its purpose is to operate not only in a closed predetermined room such as indoors, but also in a predetermined area within an arbitrarily set range such as outdoors. Another object of the present invention is to provide an ultrasonic warning system that can reliably detect a target intruder.

The principle of the method of the present invention is that an ultrasonic signal is intermittently emitted toward an area including a predetermined warning area for a relatively short period of time, and a reading start signal and a reading stop signal are determined from the reflected waves from the warning area. A standard pattern is created by creating a pattern for a predetermined period of time, collecting a plurality of reflected wave patterns over a preset number of sampling times, and performing statistical processing based on each sampling data of each of the collected reflected wave patterns. and creating a standard deviation for each sampling time, and comparing the reflection pattern according to the state of the warning area obtained by emitting an ultrasonic signal with the standard pattern,
When there is a difference between the two, it is determined whether or not the difference is within the standard deviation, thereby carrying out a warning within the warning area.

According to this method, the collected components of the reflected wave pattern can be selected by setting the predetermined period determined by the reading start signal and the reading stop signal to an appropriately set period using a delay circuit. This makes it possible to emit ultrasonic signals and determine the range for warning. As a result, the present invention can be applied even if the guard area is not only one physically closed room, but also a part of a large room that is not partitioned by walls or the like, or a predetermined area outdoors. Furthermore, by changing the timing of the reading start signal, it is possible to remove large disturbances that occur, for example, at the beginning of the reflected wave pattern, thereby preventing malfunctions caused by flying insects or the like. In addition, by adopting a method of collecting multiple reflected wave patterns through sampling, it is possible to clearly and clearly understand the current state of the restricted area as data, and what is more, it is possible to obtain standard data through statistical processing from the obtained data. By creating patterns and standard deviations, an accurate basis for comparison can be obtained. Furthermore, if a method is adopted to determine whether the difference between the reflection pattern and the standard pattern is within the standard deviation as described above, an appropriate threshold value can be set for error determination, and causes of errors caused by malfunctions can be eliminated. Can be done. Hereinafter, the system of the present invention will be explained in detail with reference to the drawings.

FIG. 1 shows an embodiment of an ultrasonic warning device according to the method of the present invention.

The ultrasonic warning device 1 is a device that detects an intruder who has entered a predetermined warning area, for example, a predetermined room, and is a device that detects an intruder who has entered a predetermined warning area, for example, a predetermined room. The ultrasonic signal S1 emitted from the wave transmitting unit 2 is reflected by the walls, fixtures, etc. of this room, and a series of reflected wave signals S2 are received and analyzed. It consists of a wave receiving section 3 for The wave transmitter 2 includes an oscillator 4 that oscillates at a suitable ultrasonic frequency, for example, a frequency of about 25 [KHz] to 40 [KHz], and the oscillation output signal S3 from the oscillator 4 is sent to the modulator 5.
is applied to the ultrasonic wave signal S1, and is modulated according to the pulse signal S4 from the pulse oscillator 6, and the modulated output (2) is emitted from the transmitter 7 into the room as an ultrasonic signal S1. The waveform of the ultrasonic signal S1 has a predetermined repetition period T1, as shown in FIG. 2a.
This is a pulse-like signal with a substantially rectangular envelope having a very short pulse duration τ1, and the values of T1 and τ1 are determined by the period and duration of the pulse signal S4, respectively. These values are usually selected to be approximately several hundred rns for T1 and approximately several Ms for τ1. Therefore, from the wave transmitter 2, several tens of KH are transmitted for several Ms every several hundred rT1S.
An ultrasonic signal of z is emitted into the room. The ultrasonic signal S1 emitted throughout the room in this way is reflected by the walls of the room, various fixtures, etc., and a series of reflected wave signals S2 made up of a superposition of countless reflected waves is generated inside the room. The wave is received by a wave receiver S provided at an appropriate location, converted into a corresponding electric signal, amplified by an amplifier 9, and then subjected to envelope detection by a wave detector 10, as shown in FIG. 2b. A detected signal S6 is obtained.

The detection signal S6, which is an analog signal, is sent to the A/D converter 11.
The clock pulse S7 from the clock oscillator 12 at
The signal is sampled at a time interval determined by , converted into a digital signal S8, and taken out. When this ultrasonic warning device 1 is installed, in order to obtain a standard pattern of reflected waves unique to the warning area when the warning area is uninhabited, the digital signal S8 is stored in the buffer memory l river 3, and the average value The data is input to a standard pattern creation circuit 16 consisting of an arithmetic circuit 14 and a memory 5.

The buffer memory 13 converts a plurality of reflection patterns obtained when there is no intruder in the guarded area to the A/D converter 1.
This is for storing the digital data digitized in step 1, and the pulse signal S4 is the read start signal S9.
As a result, the pulse signal S4 delayed by a predetermined pattern collection time Td via the delay circuit 17 is used as the reading stop signal SlO, and the counter 18 that counts the number of generated pulses of the pulse signal S4 counts up to a predetermined number. A signal output when the data is uploaded is inputted as a read inhibit signal Sll. The waveforms of the read start signal S9 and the read stop signal SlO are shown in FIG. 2c. The reading start signal ■ rises at the generation time t1 of the ultrasonic signal S1, and the reading stop signal SlO rises after a time Td has elapsed, so that the detection signal S6 corresponding to the pattern acquisition period Td shown in FIG. 2c is generated. The data is input to the buffer memory 13 as digitized data. On the other hand, the read inhibit signal Sll is
When the count value of the counter 18 reaches a predetermined value N, the state changes to r'1, and reading of the digital signal S7 is stopped regardless of the presence or absence of the signals S8 and S9. Therefore, by appropriately changing the set value N of the counter 18, the number of samples for creating the standard pattern can be arbitrarily selected. Further, by changing the amount of delay time in the delay circuit 17, or by changing the input timing of the signal S8 to the buffer memory 13 using another delay circuit, it is possible to select an appropriate range as the warning area. In this way, after inputting each sampled number of reflected wave patterns that are very close to each other from the guarded area in the absence of an intruder into the buffer memory 3, the stored contents are stored in the buffer memory 3. Simultaneously with the change to level 1, the data is input to the average value calculation circuit 14, statistical processing is performed using a simple average, a standard pattern is calculated, and the standard pattern is stored in the memo 1 river 5.

At the same time, the contents of the buffer memory 13 are input to the standard deviation value calculation circuit 19 to calculate the standard deviation value for each sampling point based on the digital signal S8, and the results are stored in the memory 20. In this way, a standard pattern is created unique to the selected warning area, and when the standard deviation value for each sampling time is determined for the standard pattern, the initial setting operation of this device is completed. The contents of the memory 15 are read out by the pulse signal S4 from the pulse oscillator 6 every time a pulse signal S4 occurs, and a digital signal S8 is applied to one input. A/D converter 1
The difference between the reflection pattern information output from 1 and the standard pattern is calculated for each sampling point, and the result is input to the discrimination circuit 22.

In the discrimination circuit 22, a difference calculation is performed. The output from the circuit 21 is compared at each sampling point with the standard deviation data stored in the memory 20 at each sampling time, and at each sampling point, the standard deviation value data and the A/D converter 1
It is determined whether the difference from the pattern from 1 is greater than or equal to the standard deviation value, and if the difference is greater than the standard deviation value, a detection signal Sl2 is output, and the alarm device 23 (for example, a buzzer, etc.) is starting to operate. According to this ultrasonic warning device, after the device starts operating and until the count value of the counter 18 reaches a predetermined value N, the reflected wave signal S2 obtained every time the ultrasonic signal S1 is emitted intermittently is clocked. Each sample is converted into digital data by the clock pulse S7 from the oscillator 112, and a predetermined portion of each reflected wave signal S2 converted into digital data is read into the buffer memory by the read start signal S9 and the read stop signal SlO. 113, and based on the reflected wave signal data received within this period, the standard pattern of the reflected wave signal and the standard deviation value for each sampling time are determined as described above. .

When calculating the standard pattern and its standard deviation value, the basic data can be the set value N of the counter 18, which can be appropriately determined to obtain a desired number of patterns. Also, which part of one reflected wave signal S2 is selected is as follows:
This is determined by the scope of the warning area. That is, in each reflected wave waveform shown in FIG. 2b, the later the component obtained from the time when the corresponding ultrasonic signal S1 was emitted (for example, t1), the more distant the reflected wave is. Since it is a wave component, a warning area can be determined by appropriately setting the value of the pattern collection time Td (see FIG. 2c) using the delay circuit 17.
Therefore, this device is suitable for use when a restricted area is physically opened.
In addition to places such as two rooms, it can be easily applied to a part of a large room that is not partitioned by walls or the like, or to a predetermined area outdoors. When the required data is prepared in the memories 15 and 20 in this way, the digital signal S8 subsequently output from the A/D converter 11 is
A difference calculation circuit 21 detects the difference between the pattern and the standard pattern prepared. In this case, if there is no intruder in the guarded area, the waveform of the detected signal S6 is very close to the standard pattern, and therefore the output from the difference calculation circuit 21 is based on the corresponding standard pattern at any sampling point. Since it is smaller than the deviation value and no detection signal is output, the alarm device 23 will not operate. On the other hand, if there is an intruder in the security area, the waveform of the detection signal S8 will be the waveform shown in FIG. A large mountain appears as shown. This peak is detected by the difference calculation circuit 21, and the standard deviation value is compared at each sampling time in the discrimination circuit 22. However, the reflected wave component from a large object such as an intruder is extremely large, and the presence of an intruder is detected. Since the disturbance in the reflection pattern due to changes greatly exceeds the standard deviation value, the detection signal S
l2 is output, the alarm device 23 is activated, and it is possible to notify that there is an intruder. Also, for example, even if the curtains in the room are slightly swaying due to a draft, the sway of the curtains will be taken into consideration when creating the standard pattern, so that the standard pattern will be created after the device goes into alert mode. This movement of the curtain will not cause any malfunction. In the above embodiment, a configuration is shown in which the presence or absence of an intruder is detected based on whether the difference between the standard pattern and the sequentially obtained reflection patterns is larger than the standard deviation value.
When detecting the presence or absence of an intruder by comparing both patterns, a large reflected image (
For example, the presence or absence of an intruder may be configured to be detected by taking into consideration whether or not the mountain indicated by the dotted line in FIG. 2b moves on the time axis.

In this way, even if the reflection pattern is disturbed by air blowing out for heating and cooling, drafts, etc., the position on the time axis where the disturbance occurs is fixed, so it can be easily distinguished from an intruder. Therefore, intruder detection can be performed more accurately. Furthermore, if there is an intruder in the guarded area, the reflected wave from the wall behind the intruder as seen from the receiver 8 (indicated by the symbol X in FIG. 3a) will be blocked by the intruder. , a phenomenon occurs in which the reflected image disappears or becomes smaller (see Figure 3b), but this phenomenon may also be taken into account when comparing the differences between the two patterns.
In this way, accurate detection of the so-so layer can be expected. Furthermore, if an insect or the like flies very close to the receiver 8, a large disturbance of the reflected wave pattern will occur in the first part of the reflected wave pattern. By not taking this into consideration when comparing, it is possible to prevent malfunctions caused by flying insects, etc. As already mentioned, the removal of the first part of the reflected wave pattern can be done very easily by changing the timing of the reading start signal S9, which is difficult to prevent with conventional ultrasonic warning devices. Malfunctions caused by hot insects, small animals, etc. can be easily prevented. In addition, in the above embodiment, in order to create a standard pattern through statistical processing based on a plurality of reflected wave patterns, the average of the plurality of reflected wave patterns obtained when the warning area is uninhabited is calculated. Although a case has been described in which values are calculated, a standard pattern is created, and this is thereafter used permanently as a standard pattern, the creation of the heading pattern of the present invention is not limited to this method.

For example, when performing statistical processing, multiple reflected wave patterns up to M times before the currently obtained reflection pattern are always stored in a buffer memory, and the average value of these stored reflection patterns is always stored. Compute and memory 1
5, and the standard pattern is rewritten every time a new reflection pattern is obtained, thereby creating a standard pattern that can be rewritten each time by the so-called moving average method. Such a standard pattern is extremely effective in an unoccupied room where changes are occurring or may occur very slowly for reasons not caused by an intruder. Such a standard pattern based on the moving average method can be easily calculated using, for example, a microprocessor. According to this ultrasonic warning device, the warning area can be arbitrarily limited even if it is not a physically separated area, so an area of a certain size can be automatically defined as in the case of the conventional trap method. It is possible to eliminate the disadvantage that even if an intruder enters a guarded area, even if there is an intruder in a guarded area, this will be detected and a false alarm will be issued.

That is, if the speed of sound is VcTrL/Sec] and the transmitter and receiver are located at approximately the same position, if the pattern collection time T is set to 0.0, the warning area will be from the receiver to (
The range is v×0.05)/2 [m]. Ru.
Any further away will be removed from the restricted area. Also,
A standard pattern is created for each location where the device is set up, and this is constantly compared with the reflection pattern to detect the presence or absence of an intruder.
The installation and adjustment of the device is extremely easy, so even if the equipment in the room is rearranged, there is no need to make any adjustments to the newly arranged room, and anyone can easily set up the device. Furthermore, since the ultrasonic waves are emitted intermittently for a very short period of time (see Fig. 2a), the transmitter 7 and the receiver 8 can be used together, which reduces the cost of the device. Furthermore, even if a plurality of ultrasonic warning devices are placed in the same room, harmful interference will not occur between the devices if the ultrasonic wave transmission timing is appropriately selected. The reason for this is that even if the direct wave or reflected wave of ultrasonic waves from one colocated device is input to the receiver of another device, the input component is stored in the standard pattern during initial setup. This is because it does not cause particularly harmful interference. According to the present invention, as explained in detail above, the present invention has excellent effects such as being extremely reliable and usable in any situation compared to the conventional ultrasonic warning system using the trap effect. play.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention, FIGS. 2a to 2c are waveform diagrams for explaining the operation of the device in FIG. 1, and FIG.
FIG. A and FIG. 3B are waveform diagrams for explaining another method of detecting an intruder according to the present invention. 1... Ultrasonic warning device, 2... Wave transmitter, 3... Wave receiver, 4... Oscillator, 5...
...Modulator, 6...Pulse oscillator, 7...
...Transmitter, 8...Receiver, 9...Amplifier, 10...Detector, 11...A/D converter, 12... ...Clock oscillator, 13...
・Buffer memo! 814...Average value calculation circuit,
15, 20...Memory, 16...Standard pattern creation circuit, 17...Delay circuit, 18...
Counter, 19...Standard deviation value calculation circuit, 21
... Difference calculation circuit, 22 ... Discrimination circuit, 23
...Alarm device, S1...Ultrasonic signal, S2
...Reflected wave signal, S3...Oscillation output signal, S4...Pulse signal, S5...Modulation output, S6...Detection signal, S7... ...Clock pulse, S8...Digital signal, S9...
...Reading start signal, SlO...Reading stop signal, Sll...Reading prohibition signal, Sl2...Detection signal.

Claims (1)

[Claims] 1 Emit ultrasonic signals intermittently toward an area including a predetermined warning area for a relatively short period of time, and create a pattern for a predetermined period determined by a reading start signal and a reading stop signal from the reflected waves from the warning area. , a plurality of reflected wave patterns are collected over a preset number of sampling times, and statistical processing is performed based on each sampling data of each collected reflected wave pattern to obtain a standard pattern and a standard deviation for each sampling time. and compare the reflection pattern according to the state of the warning area obtained by emitting an ultrasonic signal with the standard pattern, and if there is a difference between the two, check whether the difference is within the standard deviation. A warning method using ultrasonic waves, which is characterized in that a warning is carried out within the warning area by determining whether or not the warning area is present.