JPH01189582A - Detecting apparatus of moving object - Google Patents

Abstract

PURPOSE:To prevent a false information on an object shaking in a monitored space, by providing an arithmetic circuit counting the number of repetitions on the basis of a transition signal and a direction signal and a threshold circuit outputting a detection signal when an output value of the arithmetic circuit exceeds a prescribed value. CONSTITUTION:An output of an oscillator circuit 10 is emitted through a transmitter 1, and a reflected wave is received 2 and converted into a reception signal Ein. The signal Ein is mixed with reference signal E0, E0'. One signal E0 is inputted through a phase circuit 12 and outputted with the phase of an input signal advanced by 90 deg.. Therefore Doppler signals E, E' obtained by mixing 11a, 11b are also different in the phase from each other. These signals E, E' are amplified 13a, 13b and inputted to a quadrant signal generator circuit 14. In the circuit 14 a quadrant signal Q and a transition signal Z are generated. The signal Q is stored 15 and also the direction of transition is detected 16. A direction signal from a transition direction detector circuit 16 and the signal Z from the circuit 14 are computed 17, and when an output value of an arithmetic circuit 17 exceeds a threshold value of a threshold circuit 18, a detection signal is delivered from the circuit 18, so as to inform 19 the user of the presence of a moving object.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention emits continuous energy waves such as ultrasonic waves and microwaves into a monitoring space, and detects the frequency shift of the reflected waves caused by the movement of objects within the monitoring space. The present invention relates to a moving object detection device that detects the presence of a moving object within a monitoring space by detecting the presence of a moving object within a monitoring space.

[Prior Art] In general, this type of moving object detection VT device detects the movement of objects existing within the monitoring space by emitting continuous energy waves such as ultrasonic waves or microwaves of a predetermined frequency into the monitoring space. The device is configured to detect the frequency shift of the reflected wave that occurs as a Doppler effect.

A configuration as shown in FIG. 4 is known as one that detects this frequency shift and realizes the detection of a moving object in a surveillance space (see Japanese Patent Publication No. 62-43507).

In this configuration, the output of an oscillation circuit 10 that oscillates at a constant frequency is input to the transmitter 1, and the transmitter 1 emits continuous energy waves into the monitoring space, and the reflected waves from objects existing in the monitoring space are emitted from the transmitter 1. It is received by the receiver 2 and converted into a received signal Ein, and this received signal Ein is sent to a pair of mixers lla and llb.
The signals are input to the oscillator circuit 10 and mixed with a reference signal E6tE6' having the same station wave number as the output frequency of the oscillation circuit 10. Here, one reference signal E. is the output of the phase shift circuit 12,
The phases of both standards B E at E (1' are set to be different from each other. Therefore, the mixer 11a * 11
A pair of Doppler signals E and E' obtained as a beat signal at the output of signal b also have different phases. The Doppler signals E and E' are respectively processed by a binary number conversion circuit 21a,
21b, depending on whether the signal is positive or negative, 'H' or '
A logical value of "L" is assigned and converted into transponder code signals X and Y.Since the pongee code signals X and Y each have two values, four states can be expressed by a combination of the two. , these four states are Doppler signals E, E'
This shows in which quadrant the vector corresponding to the received signal Ein exists among the four quadrants of the vector plane whose basic salary is Ein. Therefore, the Tsumugi code signal X,
If the quadrant detection circuit 22 detects the combination of Y, quadrant signals I to (2) corresponding to the quadrant in which the received signal Ein exists can be obtained. The quadrant signals ■ to ■ are input to the quadrant transition direction detection circuit 23, and the received signal Ei in the vector plane
It is detected whether the n-quadrant transition is clockwise or counterclockwise. When quadrant transition is detected, the quadrant transition direction detection circuit 23 generates a transition signal Z consisting of a bipolar pulse having a positive or negative sign corresponding to the direction of transition.
The same state is maintained until the next transition occurs or the signal disappears.

Transfer signal Z° is 8! Since it is input to the dividing circuit 24, an integral value corresponding to the time when the transition signal Z° in the same direction is generated is obtained, and it is detected when the output value of the integrating circuit 24 exceeds a threshold value set in advance in the threshold circuit 25. A signal is obtained. The detection signal is input to the alarm drive circuit 19, and the presence of the moving object is displayed on the display.

As described above, by monitoring how the quadrant in which the received signal Ein exists changes within the vector plane whose basic input is the Doppler signals E and E', the presence of a moving object in the monitoring space can be detected. It detects it.

[Problem to be solved by the invention]

In the above configuration, since the transition signal Z' is integrated by the integrating circuit 24, if the transition signal Z' has the same sign and continues to be ν1 for a certain period of time or more, it is determined that a moving object exists. The criterion is the time it takes for objects in the monitoring space to move in the same direction. Therefore, if a slowly moving object exists in the monitoring space, such as when a curtain is shaking, the quadrant transition direction detection circuit 2
3 continues to output the transition signal Z", which will result in false alarms.In order to prevent such false alarms, it is possible to increase the time constant of the integrating circuit 24, but if this happens, A problem arises in that objects cannot be detected, leading to false alarms.

The present invention aims to solve the above-mentioned problems, and provides a moving object that prevents false alarms and missed alarms by detecting the movement of the object based on the distance the object moves within the monitoring space. The purpose is to provide a detection device.

[Means for Solving the Problems] The present invention generates a quadrant signal corresponding to the quadrant in which the received signal exists by combining both Doppler signals, and generates a single transition signal when the quadrant in which the received signal exists transitions. A terminal signal generation circuit that generates a quadrant signal, a memory that temporarily stores the quadrant signal, and a memory that compares the previous quadrant signal stored in the memory with the current quadrant signal to determine whether the quadrant in which the received signal exists has been transferred. A transfer direction detection circuit that sometimes generates a direction signal corresponding to the direction, and an arithmetic circuit that counts the number of transfers based on the transfer signal and direction signal by adding in one transfer direction and subtracting in the other transfer direction. The above object is achieved by including a threshold circuit that outputs a detection signal when the output value of the arithmetic circuit exceeds a predetermined threshold value.

[Function] According to the above Vt configuration, each time the quadrant in which the received signal exists shifts, the output value of the arithmetic circuit increases or decreases depending on the direction of the shift, and the output value of the arithmetic circuit increases or decreases within the monitoring space. This corresponds to the moving distance of the object, and the object will be detected when it moves a certain distance within the monitoring space.

[Embodiment 1 FIG. 1 is a block diagram of this embodiment. In the following explanation, an example will be shown in which ultrasonic waves are used as continuous energy waves, but the present invention is not limited to this, and a similar configuration can be made using microwaves or the like.

The oscillation circuit 1 continuously oscillates at a constant frequency, and the output of the oscillation circuit 10 is input to the transmitter 1, which emits ultrasonic waves into the monitoring space. If an object exists in the surveillance space,
The reflected wave is received by the wave receiver 2, and the reflected wave is converted into a received signal Ein.

Here, the wave transmitter 1 and the wave receiver 2 are constructed using piezo elements or the like.

The received signal Ein is input to a pair of mixers 11a*11b, and mixed with a reference signal Eo v Eo' having the same frequency as the output frequency of the oscillation circuit 1. One reference signal E0 is input through the phase shift circuit 12, and the phase shift circuit 12 advances the input signal in phase by 90 degrees and outputs it. There will be a difference. As a result of the mixers 11a and 11b mixing the received signal Ein with the reference signals E, E, and ' and detecting them, the pair of Doppler signals E and E' obtained as B-148 also have different phases. be.

The Doppler signals E and E' are amplified through the amplifier circuits 12a and 12b, respectively, and then sent to the quadrant signal generation circuit 14.
is input. Here, as shown in Fig. 2, we consider a vector plane with the phase difference of the reference signal Eo*E-° of 90 degrees and the Doppler signals E and E' as the basic axes, and divide this vector plane into four quadrants. By dividing into (1) to (2), the received signal Ein can be expressed as a vector on this vector plane. Therefore, if we consider four states (positive-positive, positive-negative, negative-negative, negative-positive) by combining the polarities of the Doppler signals E and E', they can be made to correspond to each of the quadrants (1) to (4) on the vector plane. Quadrant signal generation circuit 1
4, by such No. 46 processing, the quadrant in which the received signal Ein exists is detected in the vector plane and the corresponding quadrant signal Q is output, and at the same time, the received signal Ein crosses the boundary line of each quadrant. A transfer signal Z is generated when the transfer occurs. Since the quadrant signal Q only needs to represent four states, it only needs to have two or more bits, and is temporarily stored in the memory 15. The quadrant signal Q is also input to the transition direction detection circuit 16 and compared with the previous quadrant signal Q stored in the memory 15 to determine whether the quadrant has transitioned clockwise or counterclockwise. Ru. For example, as shown in FIG. 2, if the vector corresponding to the received signal Ein passes through a locus of 6-ee, it will cross the boundary line of the quadrant counterclockwise at points other than 0. Therefore, the output of the transition direction detection circuit 16 is set so that a direction signal instructing addition for counterclockwise rotation and subtraction for clockwise rotation is output. When a certain direction signal is obtained, the contents of the memory 15 are updated. The direction signal that is the output of the transition direction detection circuit 16 and the transition signal Z that is the output of the quadrant detection circuit 14 are input to the arithmetic circuit 17, and in the arithmetic circuit 17, the transition direction detection circuit 16 is The output signal is read, and 1 is added to the value stored in the arithmetic circuit 17 if the direction signal is counterclockwise, and 1 is subtracted if the direction signal is clockwise. Therefore, in the state shown in FIG. 2, the initial value of the arithmetic circuit 17 is 0, and 1
If it is transferred to pass through 1-4 e, the final value will be 3. In this way, when the absolute value of the output value of the arithmetic circuit 17 exceeds a threshold value preset in the threshold value circuit 18, the threshold value circuit 18 sends out a detection output. The detection signal is input to the alarm drive circuit 19, and the presence of the moving object is appropriately notified by the alarm device.

That is, if the operation of the arithmetic circuit 17 is illustrated, FIG.
, ), the transition direction detection circuit 16 generates a signal as shown in FIG. Then, a direction signal corresponding to the direction of the transition is output (+ indicates that the transition is counterclockwise, and - indicates that the transition is clockwise). In this way, the output value of the arithmetic circuit 17 becomes as shown in FIG. 3(e). The threshold values s and s' set in the threshold circuit 18 change as follows.
A detection output is obtained when the value exceeds . Arithmetic circuit 1
The output value of 7 is automatically reset when the received signal Ein disappears.

According to the above configuration, since a continuous energy wave is transmitted and the frequency shift of the reflected wave is detected, the frequency of the transmitted signal is fo, the moving speed of the object is y, and the propagation speed of the energy wave is C. Then, the frequency 4f of the Doppler signals E, E' becomes 1 afl # 2 vfo/e (in general, v<<c), and the Doppler signals E, E'
The frequency of is proportional to the moving speed V of the object.

Also, the wave number N of the Doppler signals E and E' generated when the object moves by a unit distance is N = 2 f o /c, so the propagation speed C of the energy wave and the transmission frequency f
If 0 is constant, the wave number N will be constant in relation to the moving speed V of the object MM. Therefore, the number of quadrant transitions of the vector corresponding to the received signal Ein on the vector plane is also constant. In other words, if it is represented by four quadrants as described above, the number of quadrant transitions will be 4XN times, which will be proportional to the distance traveled by the object.

In addition, since the direction of quadrant transition represents the direction in which the object moves, by adding or subtracting the number of transitions depending on the direction of transition when quadrant transition occurs, it is possible to know the distance and direction the object has moved. be. In other words, the moving distance of the object within the monitoring space becomes the criterion for the threshold circuit 18, and the presence of the object can be detected regardless of the time the object moves within the monitoring space.

In the above embodiment, the vector plane is divided into four quadrants, but it is clear from the principle that the greater the number of quadrants divided into four quadrants, the higher the accuracy of distance determination. As shown by the broken lines, the Doppler signals E, E
In addition to the combination of polarities of
a, nblnra.

1 [1b, Na, Wb) can be set.

[Effects of the Invention] As described above, the present invention generates a quadrant signal corresponding to the quadrant in which the received signal exists by combining a pair of Doppler signals obtained as beat signals having mutually different phases, and also detects the presence of the received signal. A quadrant signal generation circuit generates a transfer signal when the quadrant to be transferred transfers, a memory temporarily stores the quadrant signal, and a signal is received by comparing the previous quadrant signal stored in the memory with the current quadrant signal. A transition direction detection circuit that generates a direction signal corresponding to the direction when the quadrant in which the signal exists transitions, and a transition direction detection circuit that adds up in one transition direction and annihilates in the other transition direction based on the transition signal and the direction signal. It is equipped with an arithmetic circuit that counts the number of transitions, and a threshold circuit that outputs a detection signal when the output value of the arithmetic circuit exceeds a predetermined threshold, and the quadrant in which the received signal exists is transitioned. Each time, the output value of the arithmetic circuit disappears depending on the direction of the transition, and since the output value of the arithmetic circuit corresponds to the distance traveled by the object within the monitoring space, the object stays within the monitoring space. Objects can be detected if they move a certain distance, regardless of time. That is, it is possible to prevent false alarms for objects that are slowly swaying in the monitoring space, and it is also possible to prevent false alarms that occur when the time constant of the integrating circuit is increased in the conventional HIT control.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIGS. 2 and 3 are explanatory diagrams of the same operation, and FIG. 4 is a block diagram showing a conventional example. DESCRIPTION OF SYMBOLS 1... Transmitter, 2... Receiver, 10... Oscillation circuit, IIa, Ilb... Mixer, 14... Component detection circuit, 15... Memory, 16... Transfer direction detection circuit,
17... Arithmetic circuit, 18... Threshold circuit, E, E'・
...Doppler signal, El: o t E o゛...
Reference signal, Ein...received signal, Q...quadrant signal,
Z... Transfer signal. Agent Patent Attorney Ishi 1) Ai 7 Figure 2 E' 3rd leap procedure amendment permission (voluntary) 1. Displaying %B163 years 4? Patent* No. 15019 2, Name of the invention Moving object detection device 3, Relationship to the person making the amendment Case Patent applicant address 1048 Kadoma, Kadoma City, Osaka Prefecture Name (58
3) Matsushita Electric Works Co., Ltd. Representative Toshio Miyoshi 4, Agent postal code 530 5, Date of amendment order 6, Number of inventions increased by amendment None) Fake l' “Oscillation circuit 1” on page 20th line
is corrected as [oscillation circuit 10J]. [2] Figure 1 of the attached drawings is corrected as shown in the attached sheet. Agent Patent Attorney Ishi 1) Ai Shichi

Claims (1)

[Claims] (1) An oscillation circuit that oscillates at a predetermined frequency, a transmitter that sends continuous energy waves to the monitoring space using a transmission signal output from the oscillation circuit, and a transmitter that sends continuous energy waves to the monitoring space. A receiver that receives a signal and outputs a received signal, and a pair of Doppler signals that mix the received signal and a reference signal that has the same frequency as the transmitted signal but have different phases and convert it into a pair of Doppler signals that have different phases. A mixer and a quadrant that generates a quadrant signal corresponding to the quadrant in which the received signal vector exists in a vector plane with both Doppler signals as the basic axes, and also generates a transition signal when the quadrant in which the received signal exists transitions. A signal generation circuit, a memory that temporarily stores the quadrant signal, and a signal generator that compares the previous quadrant signal stored in the memory with the current quadrant signal and determines the direction of the received signal when the quadrant is transferred. a transfer direction detection circuit that generates a corresponding direction signal; an arithmetic circuit that counts the number of transfers by adding in one transfer direction and subtracting in the other transfer direction based on the transfer signal and the direction signal; A moving object detection device comprising: a threshold circuit that outputs a detection signal when an output value exceeds a predetermined threshold.