KR102158834B1 - Method and apparatus of counting people - Google Patents

Abstract

An apparatus for counting people in a target area is disclosed. This device includes a radio transceiver and a control unit. The wireless transmission/reception unit emits an impulse electromagnetic wave to the target area, and then receives a reflected signal from the target area using a phased array antenna. The control unit calculates the signal strength with respect to the reception time of the reflected signal, counts people according to the signal strength, but counts while reflecting that the signal strength is weakened in proportion to the reception time.

Description

Method and apparatus of counting people TECHNICAL FIELD

The present invention relates to a method and apparatus for counting people, and more particularly, to a method for counting people in a target area and a person counting apparatus employing this method.

Typically, a device that counts people uses a sensor installed at the door. Such a person counting device is not a device that simultaneously counts people in an unspecified target area.

Therefore, the device that counts people in the target area is still only a camera. That is, people can be counted by using technology such as face recognition of a camera. According to such a conventional method and apparatus for counting people, there are the following problems.

First, it is often not possible to count people depending on the environment of the target area. For example, people in an accident area such as a fire area or a blackout area cannot be counted by photographing.

Second, the camera can cause discomfort to people while renovating them.

Korean Patent Application Publication No. 2001-0113663 (Applicant: Bonik Corporation Proprietary Limited, name; object recognition and tracking system).

An embodiment of the present invention is to provide a method and apparatus for counting people, capable of counting people regardless of the environment of a target area, and not causing discomfort to people while counting people.

According to an aspect of the present invention, in a method of counting people in a target area, a method of counting people including steps (a) to (c) may be provided.

In the step (a), after an impulse electromagnetic wave is radiated to the target area, a phased array antenna is used to receive a reflected signal from the target area.

In step (b), the signal strength with respect to the reception time of the reflected signal is obtained.

In the step (c), people are counted according to the signal strength, but the signal strength is reduced in proportion to the reception time and counted while reflecting.

Preferably, step (c) includes steps (c1) and (c2).

In the step (c1), a decrease in signal strength in proportion to the reception time in the reflected signal is compensated, and a reflected signal of the compensation result is generated.

In the step (c2), the number of times the signal strength exceeds a set threshold value in the reflected signal of the compensation result is determined as the number of people.

Preferably, in step (c),

A variable threshold value inversely proportional to the reception time is set,

The number of times the signal strength exceeds the variable threshold is determined as the number of people.

According to another aspect of the present invention, an apparatus for counting people in a target area may include a wireless transmission/reception unit and a control unit.

The wireless transceiver unit radiates an impulse electromagnetic wave to the target area, and then receives a reflected signal from the target area using a phased array antenna.

The control unit obtains a signal strength with respect to a reception time of the reflected signal, counts people according to the signal strength, and counts while reflecting a decrease in signal strength in proportion to the reception time.

Preferably, the wireless transmission/reception unit includes an impulse signal generation unit, a transmission amplification unit, a transmission antenna, the phased array antenna, a phase shift unit, a reception amplification unit, and an analog-to-digital conversion unit.

The impulse signal generator generates an impulse signal of UWB (Ultra Wide Band) according to the digital pulse signal from the control unit.

The transmission amplifier amplifies the impulse signal from the impulse signal generator.

The transmission antenna radiates the impulse electromagnetic wave to the target area by an impulse signal from the transmission amplification unit.

The phase shifter drives the phased array antenna according to a phase shift value from the control unit and outputs a reflected signal from the phased array antenna to the reception amplifier.

The reception amplifying unit amplifies the reflected signal from the phase shift unit and outputs the amplified signal to the analog-digital conversion unit.

Further, the analog-to-digital conversion unit converts the reflected signal from the reception amplifying unit into a digital reflected signal and outputs the converted signal to the control unit.

Meanwhile, the wireless transmission/reception unit may include an impulse signal generator, a transmission amplification unit, a circulator, a phase shift unit, the phased array antenna, a reception amplification unit, and an analog-to-digital conversion unit.

The impulse signal generator generates an impulse signal of UWB (Ultra Wide Band) according to the digital pulse signal from the control unit.

The transmission amplifier amplifies the impulse signal from the impulse signal generator.

The circulator outputs an impulse signal from the transmission amplifying unit to the phase shifting unit, while outputting a reflected signal from the phase shifting unit to the reception amplifying unit.

The phase shift unit, while driving the phased array antenna according to a phase shift value from the control unit, outputs an impulse signal from the circulator to the phased array antenna, and a reflected signal from the phased array antenna Is output to the receiving amplifier.

The reception amplifier amplifies the reflected signal from the circulator and outputs it to the analog-digital converter.

The analog-to-digital conversion unit converts the reflected signal from the reception amplifying unit into a digital reflected signal and outputs the converted signal to the control unit.

According to the method and apparatus for counting people according to an embodiment of the present invention, people are counted according to the intensity of a reflected signal of an impulse electromagnetic wave, and the signal intensity is reduced in proportion to the reception time. Here, the reception time of the reflected signal may be converted into a distance between the person counting device and people.

Thus, by calculating the distance between the person counting device and the people, people can be counted.

That is, according to the method and apparatus for counting people according to an embodiment of the present invention, people can be counted using a reflected signal of an impulse electromagnetic wave without using a conventional camera. Accordingly, the following effects can be obtained.

First, people can be counted regardless of the environment of an unspecified target area. For example, people in an accident area such as a fire area or an outage area can be counted.

Second, the conventional problem of discomfort to people while repairing people by the camera can be solved.

Furthermore, according to the person counting method and apparatus of the embodiment of the present invention, the phased array antenna is used to receive a reflected signal from the target area.

Accordingly, the phased array antenna may receive reflection signals from each of the equally divided regions set toward the target region. Accordingly, a plurality of people located at the same distance as the person counting device can be accurately counted without counting only one person.

1 is a flowchart showing a method for counting people according to an embodiment of the present invention.
FIG. 2 is a diagram showing a person counting apparatus employing the method of the embodiment of FIG. 1.
3 is a flowchart illustrating a first example of step (c) of FIG. 1.
4 is a waveform diagram showing an example of a reflected signal received by the wireless transceiver of FIG. 2.
5 is a diagram illustrating an example of a compensation signal to be applied to a reflected signal in step (c1) of FIG. 3.
6 is a flowchart illustrating an example of step (b) of FIG. 1.
7 is a diagram illustrating a first example of a wireless transmission/reception unit of FIG. 2.
8 is a diagram illustrating a second example of a wireless transmission/reception unit of FIG. 2.
9 is a graph for explaining a second example of step (c) of FIG. 1.
10 is a view for explaining the operation of the phase shift unit and the phase array antenna of FIG. 7 or 8.
FIG. 11 is a diagram showing position coordinates of set equal areas in a target area according to an operation of a phase shift unit and a phase array antenna of FIG. 10.
12 and 13 are diagrams showing whether the presence of people is determined in each of the set equal parts of FIG. 11.

The following description and the accompanying drawings are for understanding the operation according to the present invention, and parts that can be easily implemented by a person skilled in the art may be omitted.

In addition, the specification and drawings are not provided for the purpose of limiting the present invention, and the scope of the present invention should be determined by the claims. Terms used in this specification should be interpreted as meanings and concepts consistent with the technical idea of the present invention so that the present invention can be most appropriately expressed.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 shows a method for counting people according to the first embodiment of the present invention.

Referring to Fig. 1, the method of the first embodiment of the present invention is a method of counting people in a target area, and includes steps (a) to (c).

In step (a), after the impulse electromagnetic wave is radiated to the target area, a phased array antenna is used to receive a reflected signal from the target area.

In the present embodiment, the impulse electromagnetic wave radiated to the target region is an ultra wide band (UWB) impulse electromagnetic wave having a frequency band of about 3 to 10 gigahertz (GHz). Accordingly, the following advantages can be obtained.

First, the electromagnetic wave is highly permeable, so it is not affected by obstacles.

Second, it is not affected by interference from surrounding signals.

Third, power consumption is reduced.

In step (b), the signal strength with respect to the reception time of the reflected signal is obtained.

In step (c), people are counted according to the signal strength, and the signal strength is reduced in proportion to the reception time and counted while reflecting.

Fig. 2 shows a person counting device 20 employing the method of the first embodiment of Fig. 1.

Referring to FIG. 2, the device 20 according to an embodiment of the present invention is a device that counts people (M1 to M4) in a target area 209, and includes a wireless transmission/reception unit 201 and a control unit 202. do.

The wireless transmission/reception unit 201 including a transmission antenna 201t and a phased array antenna 201r radiates an impulse electromagnetic wave to the target region 209 through the transmission antenna 201t, and then a phased array ( A reflected signal from the target region 209 is received through the phased array) antenna 201r.

The control unit 202 obtains the signal strength with respect to the reception time from the reception antenna 201r, and counts the people M1 to M3 according to the signal strength, while reflecting that the signal strength is weakened in proportion to the reception time. Count.

For example, as the control unit 202 obtains the decimal data “000100020001000” as a counting result, it can be seen that four people M1 to M4 are in the target area 209.

According to the method and apparatus for counting people of FIGS. 1 and 2, people M1 to M4 are counted according to the intensity of a reflected signal of an impulse electromagnetic wave from the reception antenna 201r, but in proportion to the reception time. The weakening of the signal strength is reflected.

Here, the reception time of the reflected signal means the distance between the person counting device 20 and the people M1 to M3. Thus, by calculating the distance between the person counting device 20 and the people M1 to M3, people can be counted.

That is, according to the method and apparatus for counting people according to an embodiment of the present invention, people can be counted using a reflected signal of an impulse electromagnetic wave without using a conventional camera. Accordingly, the following effects can be obtained.

First, people M1 to M4 may be counted regardless of the environment of the unspecified target area 209. For example, people M1 to M4 in an accident area such as a fire area or a power outage area may be counted.

Second, the conventional problem of discomfort to people M1 to M4 while renovating the people M1 to M4 by the camera can be solved.

Further, according to the person counting method and apparatus of this embodiment, a phased array antenna 201r is used to receive a reflected signal from the target region 209.

Accordingly, the phased array antenna 201r may receive reflection signals from each of the equal division regions set toward the target region 209. Therefore, a plurality of people M2 and M4 located at the same distance as the person counting device 20 can be accurately counted without counting only one person.

3 shows a first example of step (c) of FIG. 1. 4 shows an example of a reflected signal 401 received by the wireless transceiver of FIG. 2. 5 shows an example of a compensation signal to be applied to the reflected signal in step (c1) of FIG. 3.

A first example of step (c) of FIG. 1 will be described with reference to FIGS. 2 to 5.

The wireless transmission/reception unit 201 converts the reflected signal 401 into a digital signal and outputs it to the control unit 202. In this way, the signal strength of the reflected signal 401 input to the control unit 202 decreases in proportion to the reception time.

More specifically, the reception time is proportional to the distance between the person counting device 20 and the reflector. Further, the intensity of the received signal is in inverse proportion to the square of 4 of the distance between the person counting device 20 and the reflector.

Accordingly, the signal strength of the reflected signal 401 input to the control unit 202 decreases in proportion to the reception time. For example, the intensity of the reflected signal corresponding to the third person M3 at a distance is weaker than the intensity of the reflected signal corresponding to the second person M2 or the fourth person M2 at an intermediate distance. Similarly, the intensity of the reflected signal corresponding to the second person M2 or the fourth person M2 at an intermediate distance is weaker than the intensity of the reflected signal corresponding to the first person M1 at a close distance.

Accordingly, in step (c1), the control unit 202 compensates for a decrease in signal strength in proportion to the reception time in the reflected signal 401, and generates a reflected signal as a result of the compensation.

In this embodiment, the control unit 202 generates a reflected signal of a compensation result by applying the compensation signal 501 to the reflected signal 401.

In step (c2), the control unit 202 determines the number of times the signal strength exceeds the set threshold value in the reflected signal of the compensation result as the number of people. In this case, the set threshold value is constant regardless of the reception time.

6 shows an example of step (b) of FIG. 1. An example of step (b) of FIG. 1 will be described with reference to FIGS. 2, 4 and 6 as follows. Hereinafter, the control unit 202 processes a digital signal, and repeated reference thereto is omitted.

In step (b1), the wireless transmission/reception unit 202 amplifies the reflected signal at a predetermined ratio.

In step (b2), the noise component and the background component of the target region 209 are removed from the amplified reflected signal. In this embodiment, the wireless transceiver 202 removes a noise component from the amplified reflected signal. Also, the control unit 202 removes the background component of the target area 209 from the received signal 401 from which the noise component has been removed.

The background component of the target area 209 in step (b2) is obtained as follows.

First, by the user's operation, the person counting device 20 radiates an impulse electromagnetic wave to the target area 209 when there are no people in the target area 209, and then the phased array antenna 201r ) To receive the reflected signal from the target area 209.

Next, the person counting device 20 obtains a background component of the target region 209 by amplifying the received reflected signal at the predetermined ratio. The obtained background component of the target region 209 is stored and used in the person counting device 20.

In this way, in obtaining the signal strength with respect to the reception time of the reflected signal 401 (step (b)), as the background component when no people are present is removed from the reflected signal 401, the people are more accurately counted. Can be.

7 shows a first example of the wireless transmission/reception unit 201 of FIG. 2. In FIG. 7, the same reference numerals as in FIG. 2 denote objects of the same function. A first example of the wireless transmission/reception unit 201 will be described with reference to FIGS. 2 and 7 centering on FIG. 7 as follows.

The wireless transmission/reception unit 201 includes an impulse signal generation unit 701, a transmission amplification unit 702, a transmission antenna 201t, the phased array antenna 201r, a phase shifter 703, and reception. It includes an amplifying unit 705 and an analog-to-digital converter (ADC) 706.

When the control unit 202 generates a digital pulse signal, the impulse signal generator 701 generates an impulse signal of UWB (Ultra Wide Band) having a frequency band of about 3 to 10 gigahertz (GHz). Let it.

The transmission amplifier 702 amplifies the impulse signal from the impulse signal generator 701.

The transmission antenna 201t radiates an impulse electromagnetic wave to the target region 209 by the impulse signal from the transmission amplification unit 702.

The phase shifter 703 receives the reflected signal from the phase array antenna 201r while driving the phased array antenna 201r according to the phase shift value Dps from the control unit 202, receiving amplification unit ( 705).

The reception amplifying unit 705, for example, a low noise amplifier (LNA), amplifies the reflected signal from the phase shift unit 703 at a certain ratio, and then amplifies the noise component from the amplified reflected signal. Remove (see Fig. 6).

In addition, the analog-to-digital conversion unit 706 converts the reflected signal from the reception amplifying unit 705 into a digital reflected signal and outputs it to the control unit 202.

8 shows a second example of the wireless transmission/reception unit 201 of FIG. 2. In FIG. 8, the same reference numerals as in FIG. 2 indicate objects of the same function. In the second example of Fig. 8, the transmitting antenna (201t in Fig. 2) and the receiving antenna (201r in Fig. 2) are replaced with one phased array antenna 804. A second example of the wireless transmission/reception unit 201 will be described with reference to FIGS. 2 and 8 centering on FIG. 8 as follows.

The wireless transmission/reception unit 201 includes an impulse signal generation unit 701, a transmission amplification unit 702, a circulator 801, a phase shift unit 803, the phased array antenna 804, and reception amplification. A unit 705 and an analog-to-digital conversion unit (ADC) 706 may be included.

When the control unit 202 generates a digital pulse signal, the impulse signal generator 701 generates an impulse signal of UWB (Ultra Wide Band) having a frequency band of about 3 to 10 gigahertz (GHz). Let it.

The transmission amplifier 702 amplifies the impulse signal from the impulse signal generator 701.

The circulator 801 outputs the impulse signal from the transmission amplifying unit 702 to the phase shifting unit 803, while outputting the reflected signal from the phase shifting unit 803 to the receiving amplifying unit 705 do.

The phase shifting unit 803 outputs an impulse signal from the circulator 801 to the phased array antenna 804 while driving the phased array antenna 804 according to the phase shift value Dps from the control unit 202 On the other hand, the reflected signal from the phased array antenna 804 is output to the circulator 801.

The reception amplifier 705, for example, a low noise amplifier (LNA), amplifies the reflected signal from the circulator 801 at a certain ratio, and then removes the noise component from the amplified reflected signal. (See Fig. 6).

In addition, the analog-to-digital conversion unit 706 converts the reflected signal from the reception amplifying unit 705 into a digital reflected signal and outputs it to the control unit 202.

9 is a graph for explaining a second example of step (c) of FIG. 1.

1, 2, and 9, in the second example of step (c), the control unit 202 is set with a variable threshold value 901 that is inversely proportional to the reception time. Also, the control unit 202 determines the number of times the signal strength exceeds the variable threshold value 901 as the number of people.

According to the second example of step (c) of FIG. 9, unlike the first example of step (c) of FIG. 3, the control unit 202 reflects the weakening of the signal strength by using the variable threshold value 901. .

Here, as step (b) of FIG. 1, the example of FIG. 6 is equally applied.

10 is a view for explaining the operation of the phase shifting unit 703 or 803 and the phased array antenna 201r or 804 of FIG. 7 or 8. FIG. 11 shows position coordinates of set equal areas in a target area (209 of FIG. 2) according to the operation of the phase shifter 703 or 803 and the phase array antenna 201r or 804 of FIG. 10. In FIG. 11, the X axis indicates a horizontal scan axis, the Y axis indicates a vertical scan axis, and the Z axis indicates a distance axis.

First, a case where the phase shifting unit 703 and the phased array antenna 201r of FIG. 7 are applied will be described further as follows.

2, 7, 10 and 11, the phase shifting unit 703 drives the phased array antenna 201r according to the phase shifting value Dps from the control unit 202, while the phased array antenna 201r The reflected signal from is output to the reception amplifier 705.

Accordingly, the phased array antenna 201r may receive reflection signals 1001 having a narrow width from each of (m+1) x (n+1) set equally divided areas toward the target area 209. .

Meanwhile, a case in which the phase shifting unit 803 and the phased array antenna 804 of FIG. 8 are applied will be described further as follows. In the second example of Fig. 8 described above, the transmitting antenna (201t in Fig. 2) and the phased array antenna (201r in Fig. 2) are replaced with one phased array antenna 804.

2, 8, 10, and 11, the phase shifting unit 803 drives the phased array antenna 804 according to the phase shift value Dps from the control unit 202, and from the circulator 801 The impulse signal of is output to the phased array antenna 804, while the reflected signal from the phased array antenna 804 is outputted to the circulator 801.

Accordingly, the phased array antenna 804 radiates an impulse electromagnetic wave to each of (m+1) x (n+1) set equally divided areas toward the target area 209, and then (m+1) x ( Reflected signals may be received from each of the n+1) set equally divided regions 1101.

12 and 13 show that the presence or absence of people is determined in each of the set equal parts of FIG. 11. In FIG. 13, the X axis indicates a horizontal scan axis, the Y axis indicates a vertical scan axis, and the Z axis indicates a distance axis.

2, 10, 12, and 13, the phased array antenna 201r or 804 receives reflection signals 1001 having a narrow width from each of the equally divided regions 1301 set toward the target region 209. .

Therefore, a plurality of people M2 and M4 located at the same distance as the person counting device 20 can be accurately counted without counting only one person.

The determination data 1201 and 1301 include phase shift values of a phase shift unit, position coordinates of each set equal division area corresponding to each phase shift value, and a determination result. In the case of the judgment data of FIG. 9, it can be seen that 22 people exist in the target area 209.

As described above, according to the method and apparatus for counting people according to the embodiment of the present invention, people are counted according to the strength of the reflected signal of the impulse electromagnetic wave, but the signal strength is weakened in proportion to the reception time. Is reflected.

Here, the reception time of the reflected signal may be converted into a distance between the person counting device and the person. Thus, by calculating the distance between the person counting device and the people, people can be counted.

That is, according to the method and apparatus for counting people according to an embodiment of the present invention, people can be counted using a reflected signal of an impulse electromagnetic wave without using a conventional camera. Accordingly, the following effects can be obtained.

First, people can be counted regardless of the environment of an unspecified target area. For example, people in an accident area such as a fire area or an outage area can be counted.

Second, the conventional problem of discomfort to people while renovating people by the camera can be solved.

Further, according to the person counting method and apparatus of the embodiment of the present invention, a phased array antenna is used to receive a reflected signal from a target area.

Accordingly, the phased array antenna may receive reflected signals from each of the equally divided regions set toward the target region. Therefore, a plurality of people located at the same distance as the person counting device can be accurately counted rather than counted as one person.

So far, we have looked at the center of the preferred embodiment for the present invention. Those of ordinary skill in the art to which the present invention pertains will understand that the present invention can be implemented in a modified form without departing from the essential characteristics of the present invention.

Therefore, the disclosed embodiment should be considered from an illustrative point of view, not a limiting point of view. The scope of the present invention is shown in the claims rather than the above description, and the invention claimed by the claims and the inventions equivalent to the claimed invention should be construed as being included in the invention.

It is also likely to be used to count animals.

20: person counting device, 201: wireless transmission/reception unit,
202: control unit, 201t: transmitting antenna,
201r: phased array antenna, 209: target area,
M1 to M4: people, 701: impulse signal generator,
702: transmission amplification unit, 703: phase shifting unit,
705: receiving amplification unit, 706: analog-digital conversion unit,
801: circulator, 803: phase shifting unit,
804: phased array antenna.

Claims (6)

In the method of counting people in the target area,
(a) radiating impulse electromagnetic waves to the target region, and then receiving a reflected signal from the target region using a phased array antenna;
(b) finding the signal strength with respect to the reception time of the reflected signal; And
(c) counting people according to the signal strength, but counting while reflecting that the signal strength is weakened in proportion to the reception time; and
The step (b) is
Including; removing the background component from the reflected signal,
The background component is generated based on a reflected signal obtained when no person is present in the target area. The method of claim 1, wherein step (c),
(c1) compensating for a decrease in signal strength in proportion to the reception time in the reflected signal to generate a reflected signal as a result of compensation; And
(c2) determining the number of times the signal intensity exceeds a set threshold value in the reflected signal of the compensation result as the number of people. The method of claim 1, wherein in step (c),
A variable threshold value inversely proportional to the reception time is set,
The number of times the signal strength exceeds the variable threshold value is determined as the number of people. In the device for counting people in the target area,
A wireless transmission/reception unit for radiating impulse electromagnetic waves to the target area and then receiving a reflected signal from the target area using a phased array antenna; And
Including; a control unit that calculates the signal strength with respect to the reception time of the reflected signal, counts people according to the signal strength, and counts while reflecting that the signal strength is weakened in proportion to the reception time,
The control unit
After removing the background component from the reflected signal, the people are counted,
The background component is generated based on a reflected signal obtained when no person is present in the target area. The method of claim 4,
The wireless transmission/reception unit includes an impulse signal generator, a transmission amplification unit, a transmission antenna, the phased array antenna, a phase shifting unit, a reception amplification unit, and an analog-to-digital conversion unit,
The impulse signal generator generates an impulse signal of UWB (Ultra Wide Band) according to the digital pulse signal from the control unit,
The transmission amplifier amplifies the impulse signal from the impulse signal generator,
The transmission antenna radiates the impulse electromagnetic wave to the target region by an impulse signal from the transmission amplification unit,
The phase shift unit, while driving the phased array antenna according to a phase shift value from the control unit, outputs a reflected signal from the phased array antenna to the reception amplifier,
The reception amplifying unit amplifies the reflected signal from the phase shift unit and outputs the amplified signal to the analog-digital conversion unit,
The analog-to-digital conversion unit converts the reflected signal from the reception amplifying unit into a digital reflected signal and outputs the converted signal to the control unit. The method of claim 4,
The wireless transmission/reception unit includes an impulse signal generation unit, a transmission amplification unit, a circulator, a phase shift unit, the phased array antenna, a reception amplification unit, and an analog-to-digital conversion unit,
The impulse signal generator generates an impulse signal of UWB (Ultra Wide Band) according to the digital pulse signal from the control unit,
The transmission amplifier amplifies the impulse signal from the impulse signal generator,
The circulator outputs an impulse signal from the transmission amplifying unit to the phase shifting unit, while outputting a reflected signal from the phase shifting unit to the reception amplifying unit,
The phase shift unit, while driving the phased array antenna according to a phase shift value from the control unit, outputs an impulse signal from the circulator to the phased array antenna, and a reflected signal from the phased array antenna Output to the circulator,
The reception amplifier amplifies the reflected signal from the circulator and outputs the amplified signal to the analog-digital converter,
The analog-to-digital conversion unit converts the reflected signal from the reception amplifying unit into a digital reflected signal and outputs the converted signal to the control unit.

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