KR20170140004A - A Security Apparatus using Laser Scanner - Google Patents

Abstract

The present invention provides a crime prevention apparatus by using a laser scanner, comprising: a laser scanner unit including two rotational optical modules transmitting laser beams while rotating around a rotational axis to form an optical plane perpendicular to the rotational axis and receiving a reflection beam reflected from an object on the optical plane; a time measurement unit measuring time from a first temporal point when each of the rotational optical modules transmits the laser beam to a second temporal point when each of the rotational optical modules receives the reflection beam; a rotational angle calculation unit calculating a rotational angle at the second temporal point from a preset initial position with respect to each of the rotational optical modules; a control unit taking initial space information of a surrounding space by using the time measured by the time measurement unit and the rotational angle calculated by the rotational angle calculation unit, comparing the initial space information with real space information of the surrounding space taken by using the time and the rotational angle measured afterwards, and determining that there exists an external intruder in the surrounding space in case that there is a difference between the initial space information and the real space information. The present invention can take information related to external intrusion only with a clock time and a calculation circuit conventionally used even without a separate high priced ADC.

Description

[0001] The present invention relates to a security device using a laser scanner,

The present invention relates to a security device using a laser scanner, and more particularly, to a security device using a laser scanner having two rotating optical modules, even if an expensive ADC for converting an analog signal into a digital signal is not used. And a security device using a laser scanner which can accurately recognize an intrusion position.

Generally, in order to recognize the shape of a forward object or to measure a distance to a forward object, a method of transmitting an optical signal or an acoustic signal to a forward object and receiving the reflected signal is mainly used. SONAR, and LIDAR systems.

The radar system is mainly used for detecting and monitoring large objects such as airplanes. The sonar system is mainly used for detecting and monitoring submarines and fishes in the water. The radar system is used for measurement, construction, Detection and so on.

Among these, in particular, the LIDAR (light detection and ranging) system uses a visible light or an infrared laser light. Therefore, when compared with the radar system or the sonar system using electromagnetic waves or ultrasonic waves with severe interference or diffraction, It is possible to acquire the distance information and shape information with respect to the object very precisely. Recently, the distance from the preceding vehicle has been measured and the utilization rate of the vehicle has been increasing, for example, in a smart vehicle that enables unattended driving or securing the safety distance of the traveling vehicle .

In order to measure the distance to the front object, the LIDAR system uses a time-of-flight (TOF) method in order to measure the distance from the front object And the distance to the forward object is measured using the method described in detail in [1].

However, in the case of the conventional Lada system, since the clock bandwidth of the timer is large in comparison with the reception bandwidth of the light receiving unit (or the photodetector) for receiving the short pulse optical signal, An error of the time measurement occurs, which causes an error in the distance measurement.

Therefore, in order to minimize the measurement error due to the bandwidth difference between the clock timer and the light receiving unit, an expensive ADC (Analog-Digital Converter) having a very high sampling rate of the reflected light reception signal (that is, excellent in distance resolution) The size and cost of the entire Lada system are increased.

[Patent Document 1] Korean Laid-open Patent No. 1998-044692 (published on September 5, 1998)

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems of the conventional art, and it is an object of the present invention to provide a laser light source that transmits a laser light in a horizontal direction ahead without using an expensive ADC that converts an analog signal to a digital signal, By using a laser scanner including two rotating optical modules that receive light reflected from the surface of an object, the relationship between the time required for each optical module to receive the reflected light and the rotation angle determines whether intruders are intruded or not, And to provide a security device using a laser scanner capable of accurately recognizing a position.

It is another object of the present invention to provide a rotary optical module in which a condensing lens for focusing reflected light toward a light receiving module in front of a rotating mirror is provided in the rotary optical module, And to provide a crime prevention device using a laser scanner capable of remarkably improving light receiving efficiency of the light receiving module by forming a hole.

It is another object of the present invention to provide a security device using a laser scanner capable of remarkably improving the control efficiency of a laser scanner by constituting a rotating mirror as a MEMS mirror that rotates forward and backward by a piezoelectric effect, .

According to an aspect of the present invention, there is provided a security device using a laser scanner, which transmits laser light while rotating around a rotation axis so as to form an optical plane orthogonal to the rotation axis, A time measuring unit for measuring a time from a first point of time at which the rotating optical module transmits the laser light to a second point of time at which the reflected light is received, A rotation angle calculating section for calculating a rotation angle at the second time point based on a predetermined initial position with respect to the rotation optical module of the rotation optical module, Acquires the initial spatial information of the surrounding space, and acquires the initial spatial information of the surrounding space acquired using the time and the rotation angle measured thereafter If the real space information where the differences in comparison with the initial spatial information is characterized in that a control unit determines that the external attacker generated in the surrounding space.

Also, the time measuring unit is a clock timer, and the controller acquires the initial spatial information and the actual spatial information of the peripheral space using the change in the number of clocks of the clock timer with respect to the rotation angle of the continuously changing second viewpoint .

The rotation optical module may include a light emitting module that transmits laser light, a rotation mirror that rotates about the rotation axis so as to form a light plane in a direction orthogonal to the rotation axis, And a light receiving module for receiving the reflected light refracted by the reflecting lens. The light receiving module receives the reflected light refracted by the reflecting lens in a predetermined second direction.

The reflection lens is formed of a condenser lens installed in front of the rotary mirror module and focusing the reflected light to the light receiving module, and a through hole through which the light transmitted from the light emitting module passes is formed in the center part.

In addition, the rotating mirror module is formed of a MEMS mirror rotating in the normal and reverse directions about the rotation axis by a piezoelectric effect.

In addition, a plurality of optical T / R modules including the light emitting module and the light receiving module are provided, and each of the optical T / R modules is arranged in a rocking manner with a phase difference in the vertical direction or the horizontal direction.

As described above, in the security system using the laser scanner according to the present invention, each of the two rotating optical modules transmits the laser light, and the rotation angle when receiving the reflected light and the rotation angle when receiving the reflected light, In this case, the measurement error included in the reflected light reception time of each of the rotation optical modules (that is, the error due to the difference between the clock bandwidth and the light receiving portion bandwidth) are canceled each other, It is possible to acquire information related to intrusion of a very accurate outsider by using only a normal clock timer and an operation circuit.

1 is a view for explaining the operation of a laser scanner applied to a security device using a laser scanner according to an embodiment of the present invention;
FIGS. 2A and 2B are diagrams for explaining a method of recognizing the distance to a forward object and the surface shape of a forward object by a crime prevention device using the laser scanner shown in FIG.
3 is a diagram for explaining a method for determining whether an intruder is intruded by using the security device of FIG. 1, and FIG.
Figs. 4 to 6 are views for explaining the optical system configuration of the rotating optical module applied to Fig. 1. Fig.

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

FIG. 1 is a view for explaining an operational configuration of a laser scanner applied to a security device using a laser scanner according to an embodiment of the present invention. FIGS. 2a and 2b are views showing a security device using a laser scanner according to FIG. A method of recognizing a distance between a front object and a surface shape of a forward object.

3 is a view for explaining a method for judging whether or not an intruder intrudes by using the crime prevention device of FIG. 1, and FIGS. 4 to 6 are views for explaining the optical system configuration of the rotating optical module applied to FIG. 1 to be.

A security device using a laser scanner according to the present invention is a security device that transmits laser light while rotating around the rotation axis so as to form an optical plane orthogonal to the rotation axis and receives two reflected light beams reflected from an object on the optical plane, A time measuring unit for measuring a time from a first time when each of the rotating optical modules transmits the laser light and a second time when the reflected light is received; A rotation angle calculator for calculating a rotation angle at the second time point based on the initial position, and a controller for acquiring initial spatial information of the peripheral space using the time measured by the time measuring unit and the rotation angle calculated by the rotation angle calculator And the actual spatial information of the peripheral space acquired using the time and the rotation angle measured thereafter is stored in the initial space In contrast to the case where the difference correction is configured to include a control unit that determines that an external attacker generated in the surrounding space.

In this case, the two rotation optical modules are spaced apart from each other by a predetermined distance, and each of the rotation optical modules includes a light emitting module for transmitting laser light in a visible light or an infrared light region, A driving motor for rotating the rotating mirror about the rotating shaft so as to form an optical plane in a direction perpendicular to the rotating shaft, A reflecting lens for reflecting the reflected light in a predetermined second direction, and a light receiving module for receiving the reflected light refracted by the reflecting lens.

Further, a light collecting lens may be further provided between the light receiving module and the reflecting lens so as to focus reflected light on the light receiving module, if necessary, to further improve the light receiving efficiency of the light receiving module.

In addition, the light emitting module may be configured to transmit a pulse-shaped laser beam having a predetermined short bandwidth, and the time measuring unit may be preferably configured using a conventional clock timer that generates a pulse signal by an oscillator or the like .

In this case, in the laser scanner used in the conventional ladder system, since the pulse bandwidth of the laser light is shorter than the pulse width of the clock timer, a measurement error of reflected light reception time is generated according to the difference of the bandwidth, An expensive ADC having a very short signal sampling time is used.

However, since the crime prevention device using the laser scanner according to the present invention configured as described above includes all of the errors according to the difference in bandwidth described above with respect to the time information of the reflected light received by each of the rotating optical modules, When the distance to an object is calculated by using the time, the errors are canceled each other. Therefore, even if an expensive ADC is not used, it is possible to measure the distance with a very accurate level and to recognize the surface shape of an object using only a normal clock timer and an arithmetic circuit .

Meanwhile, the rotation angle calculation unit and the control unit can be preferably configured using a normal operation circuit, a logic circuit, a microcomputer, or the like.

Next, with reference to FIGS. 2A and 2B, a method of measuring the distance to an object and recognizing the surface shape of the object using the laser spot scanner according to the present invention will be described in detail.

First, assuming that the rotating optical module 1 (optical scanner # 1) and the rotating optical module 2 (optical scanner # 2) are spaced apart from each other by a distance D and rotate counterclockwise, the initial position of the motor And the rotation speed of the motor can be known, the rotation angle calculation unit can calculate the rotation angle ([theta] ₁₁ , [theta] ₂₁ ) at the second time point when the respective rotation optical modules recognize the forward object for the first time .

In addition, the time measuring unit measures the reflected light reception time, which is the time between the first time when each of the rotation optical modules transmits the laser light and the second time when the reflected light is received, .

Further, since each of the rotation optical modules continuously recognizes the front object along the surface of the forward object from the first recognition of the forward object, the second viewpoint is represented by a continuously changing rotation angle as shown in the graph of FIG. 2B , And the amount of change in the number of clocks (i.e., the reflected light reception time) for the second time point continuously displayed in this manner can be graphically displayed.

That is, as shown in FIG. 2B, in the case of the rotating optical module 1 and the rotating optical module 2, the second time point is in a range of? ₁₂ and? ₂₁ to? ₂₂ at? ₁₁ , The time variation can be represented by the number of clocks of the clock timer.

In this case, for example, the control unit calculates the distance between the laser scanner unit and the front object by the triangulation method using the rotation angle (? ₁₁ ,? ₂₁ ) at the time when the front object is recognized for the first time and the separation distance between the rotation optical module The controller calculates the distance using the rotation angles (? ₁₂ ,? ₂₂ ) at the time when the front object has been recognized last time, or calculates the distance using the rotation angle section And calculate the distance to the forward object using the rotation angle of the forward object.

Also, as described above, when the change amount of the number of clocks with respect to the rotation angle of the continuously changing second point of time is plotted, the profile of the profile changes to the surface shape of the forward object (specifically, the shape of the surface facing the laser scanner portion) It is possible to recognize not only the distance to the front object but also the front surface shape of the front object similarly to the conventional ladder system.

However, in this case, if the relationship between the change in the number of clocks with respect to the rotation speed of the motor (or the rotation angle of the rotating optical module) when the laser light is reflected in the same plane is stored in advance in the memory or the like, When the relationship between the reception time and the rotation angle is corrected, a profile more similar to the surface shape of the forward object can be obtained.

In addition, the control unit may use the change in the number of clocks of the clock timer with respect to the rotation angle of the second viewpoint, which is continuously changed when a plurality of second viewpoints are received by each of the rotation optical modules, A rotation angle at which the same object is recognized is first specified and at least one of the distance and the surface shape is recognized for each of the objects recognized at the specified rotation angle.

That is, when a plurality of objects exist in front of the laser scanner unit, as described above, a plurality of the second viewpoint appearing as a section in which the rotation angle continuously changes is displayed for each rotating optical module.

In this case, the control unit compares the profiles of the graphs of the variation in the number of clocks with respect to the rotation angle of the second viewpoint continuously changing with respect to each of the rotation optical modules, and determines the rotation angle of the second viewpoint The rotation optical module 1 or 2 measures the rotation angle at which the same object is recognized (that is, the second point of time), and the distance and the surface shape are measured for each of the objects recognized at the specified rotation angle in the manner described above.

A method for determining whether an intruder is intruded using the crime prevention device according to the present invention is as follows. First, the controller acquires initial spatial information of a space around a door using a rotating optical module.

In this case, the initial spatial information refers to the distance between the ceiling, the wall, and the bottom surface surrounding the optical plane formed by the laser scanner and the surface shape thereof, the distance between the ceiling, the wall, And the like.

Thus, the acquired initial spatial information may be displayed as shown in the upper right of FIG. 3, and then the controller acquires actual spatial information using the rotating optical module.

In this case, the controller acquires the initial spatial information and the actual spatial information of the peripheral space using the change in the number of clocks of the clock timer with respect to the rotation angle of the continuously variable second viewpoint as described above. If there is no external intruder, the profile of the graph of the relationship between the reception time and the rotation angle of the reflected light is obviously the same as the initial spatial information. However, if there is an external intruder, A change in the profile occurs at a rotation angle.

Accordingly, when there is a change in the profile, the controller determines that an external intruder has occurred, and provides the user with information on the intrusion of the intruder and the intrusion location, or may generate an alarm or the like.

When the optical system of the rotating optical unit is constructed as shown in Fig. 1, the reflecting lens is installed in one half of the rotating mirror. In this case, as shown in Fig. 4 (a) It is impossible to receive the reflected light of the area adjacent to the optical path, and the light receiving efficiency is greatly reduced.

Accordingly, in order to compensate for this, a separate condensing lens is used in the optical system of FIG. 1. However, the optical system having the above-described configuration has disadvantages of increased volume and cost.

In order to solve this problem, in another embodiment of the present invention, the rotating optical module is configured as shown in FIG. 4 (b).

The rotary optical module shown in FIG. 4 (b) is composed of a condenser lens which is provided at the front of the rotating mirror for focusing the reflected light toward the light receiving module and concentrating the reflected light to the light receiving module, A through hole through which light transmitted from the module passes is formed.

With the above-described structure, the rotating optical module shown in FIG. 4B has a configuration in which the highly reflected flux around the transmission light is received in a donut form and focused on the light receiving portion, so that the structure is simple, But also has an advantage that the light receiving efficiency can be remarkably improved.

In addition, in the above-described embodiment, the case where the rotating mirror is rotated by the driving motor has been described as an example, but the present invention is not limited thereto. If necessary, the rotating mirror may be rotated (MEMS) mirror rotating in the forward and reverse directions.

In the above-described embodiment, the optical transmission / reception module including the light emitting module and the light receiving module is formed as a pair. However, the present invention is not limited thereto, and the optical transmission / reception modules may be composed of a plurality .

In this case, as shown in FIG. 6, each of the optical T / R modules may be arranged so that the optical path has a phase difference (or an angle difference) in the vertical direction or the horizontal direction. In the case where the optical path has a phase difference in the vertical direction, It is possible to improve the reliability of a crime prevention apparatus that allows detection by another light emitting module to be continuously performed when any one of the light emitting modules fails in the case of having a phase difference in the horizontal direction There is an advantage.

Claims (6)

A laser scanner part including two rotating optical modules for transmitting laser light while rotating around the rotation axis so as to form an optical plane orthogonal to the rotation axis and receiving reflected light reflected from an object on the optical plane;
A time measuring unit for measuring a time from a first time when each of the rotation optical modules transmits the laser light to a second time when the reflected light is received;
A rotation angle calculator for calculating a rotation angle at the second time point based on a predetermined initial position for each of the rotation optical modules; And
And acquiring initial spatial information of the peripheral space using the time measured by the time measuring unit and the rotational angle calculated by the rotational angle calculating unit, and acquiring initial spatial information of the peripheral space acquired using the time and the rotational angle measured thereafter And a control unit for determining that an external intruder is generated in the peripheral space when there is a difference between the spatial information and the initial spatial information. The method according to claim 1,
Wherein the time measuring unit is a clock timer,
Wherein the controller acquires the initial spatial information and the actual spatial information of the peripheral space using a change in the number of clocks of the clock timer with respect to a rotation angle of the continuously changing second viewpoint. 3. The method according to claim 1 or 2,
The rotation optical module includes a light emitting module for transmitting laser light, a rotating mirror module for refracting the light while rotating around the rotation axis so that the laser light transmitted from the light emitting module forms an optical plane in a direction orthogonal to the rotation axis, And a light receiving module for receiving the reflected light refracted by the reflecting lens, and a light receiving module for reflecting the light reflected from the object on the optical plane in a predetermined second direction. Security device. The method of claim 3,
Wherein the reflection lens comprises a condenser lens installed in front of the rotary mirror module and concentrating the reflected light to the light receiving module, and a through hole through which the light transmitted from the light emitting module passes is formed at a central portion thereof Security device. The method of claim 3,
Wherein the rotating mirror module is composed of a MEMS mirror rotating in the normal and reverse directions about the rotation axis by a piezoelectric effect. The method of claim 3,
Wherein the optical transmission / reception module comprises a plurality of optical transmission / reception modules including the light emitting module and the light receiving module, wherein the optical transmission / reception modules are arranged in a rocking manner in which optical paths are vertically or horizontally shifted from each other. Device.

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