KR20190084574A - LiDAR scanning device - Google Patents

Abstract

The present invention relates to a LiDAR scanning device measuring a distance, a direction, a speed, and the like to a target object by irradiating the laser beam to the target object, and analyzing the laser beam reflected by the target object. According to an embodiment of the present invention, the LiDAR scanning device comprises: a transmission irradiating a laser beam; a mirror scanner repeatedly rotating a laser beam irradiated from the transmission unit in a predetermined angle range to be reflected in various directions; a multi-mirror irradiating the laser beam reflected from the mirror scanner onto the target object and receiving the laser beam reflected from the target object; a reception unit receiving the laser beam reflected from the multi-mirror; and a rotating motor rotating the multi-mirror.

Description

LiDAR scanning device < RTI ID = 0.0 >

The present invention relates to a Lada scanning apparatus that irradiates a laser beam onto a target object, analyzes a laser beam reflected by the target object, and measures a distance, a direction, and a velocity to the target object.

In general, the LIDAR system (Light Detection and Ranging system) irradiates a laser to a target object, analyzes the laser beam reflected by the target object, and measures the distance, direction, and speed to the target object System.

These Lidar systems are used for weather observation and distance measurement. Recently, they have been used for autonomous vehicles, meteorological observations using satellites, unmanned robot sensors, and technologies for 3D image modeling.

The laser beam can be irradiated with a sine wave or pulsed wave according to the measurement method. In order to move the measurement point of the laser beam in 2D mapping or 3D shape measurement, a Lada scanning device composed of a motor or a mirror is required.

In recent years, as a sensor for measurement of a peripheral shape for a mobile platform, Lada has been attracting attention. In the case of autonomous vehicles and unmanned vehicles, for example, the vehicle runs along the ground, so the object requiring measurement is mainly on the ground. Therefore, in the case of an autonomous vehicle, it is not necessary to use a wide measurement angle in the vertical direction, but a wide measurement area in the horizontal direction is required.

In addition, since there are many objects traveling at a high speed of 100 km or more in the traveling environment of the vehicle, the measurement speed of the lidar can be detected quickly.

FIG. 1 is a perspective view illustrating a conventional RIDAR scanning device, and FIG. 2 is a view illustrating a measurement area of the RIDAR scanning device of FIG. 1. Referring to FIG. The prior art of Fig. 1 is the Lada scanning device disclosed in U.S. Publication No. US2014293263A1.

1 includes a transmitting unit 35 and a receiving unit 40, a first axis scanning motor 20, a multi-facet mirror 10 ', a rotating table 50, a second axis scanning unit 20, A motor (not shown), and the like. Here, the first axis is a horizontal rotation axis for scanning the vertical direction, and the second axis is a vertical rotation axis for scanning the horizontal direction.

The beam transmitted from the transmitting section 35 is transmitted in various vertical directions by a mirror that is rotated around the first axis as a center axis and the beam reflected from the mirror as the rotating table 50 rotates about the second axis Are transmitted in the vertical and horizontal directions. Thereafter, the transmitted beam is reflected by the object, and the reflected beam from the object is reflected by the multi-faceted mirror and received by the receiver.

Such a Ridas scanning apparatus A has an advantage that it can measure 360 degrees in the horizontal direction as shown in FIG. 2, and can measure 10 to 170 degrees in the vertical direction according to the design of the multi-faceted mirror.

However, since the conventional Ridas scanning apparatus A uses two motors for the first axis and the second axis, the scanning speed is as low as several tens of Hz, which is not suitable for high-speed scanning.

Since the rotary table 50 itself rotates during horizontal scanning, the transmission unit 35, the receiving unit 40, the first axis scanning motor 20, the multi-facet mirror 10 And all the various circuits are continuously subjected to the centrifugal force due to the rotation, there is a problem that the durability of these parts is adversely affected, and thus there is a problem that the horizontal scanning speed is limited.

FIG. 3 is a diagram illustrating a prior art Ridas scanning device, and FIG. 4 is a view illustrating a measurement area of the Ridas scanning device of FIG. 3. Referring to FIG. The prior art of FIG. 3 is described in "Design and characterization of a 256x64-pixel single-photon imager in CMOS for MEMS based laser scanning time-of-flight sensor" (OSA Publishing, Vol. 20, Issue 11, pp. 11863-11881 (2012).

The Lada scanning apparatus B shown in Fig. 3 includes a transmitting unit 1, a receiving unit 2, and a biaxial MEMS scanner 3. The Ridas scanning device B of FIG. 3 uses a transmitter 1 composed of a plurality of lasers to widen the measurement area. The beam transmitted from the transmission unit 1 is reflected by the biaxial MEMS scanner 3 in the vertical and horizontal directions to detect the object.

3, the direction in which the transmission beam is irradiated is changed by the biaxial MEMS scanner 3, and after the reception beam reflected by the object passes through the condenser lens 4, The position of each of the sensors changes. The receiving unit 2 is composed of an M × N multi-channel receiving element or an image sensor so that the receiving unit 2 can receive signals in all directions according to the directions to be irradiated.

Since the Ridas scanning apparatus B does not use a motor, the output of the transmission unit 1 can be increased to several tens of kHz, and high-speed scanning can be performed. Thus, the problem of the above-described Lada scanning apparatus A can be solved.

However, such a conventional Ridas scanning device B is difficult to have a wide measurement angle of 50 degrees or more due to the angular limitations of the biaxial MEMS scanner 3, as shown in Fig. 4, (M x N pixels) is required, which increases the cost and complicates the configuration.

U.S. Published Patent Application No. US2014293263A1

Design and characterization of a 256x64-pixel single-photon imager in CMOS for MEMS based laser scanning time-of-flight sensor (OSA Publishing, Vol. 20, Issue 11, pp. 11863-11881 (2012))

SUMMARY OF THE INVENTION It is an object of the present invention to provide a Lada scanning apparatus capable of solving the problems of the above-described conventional techniques.

A ladder scanning apparatus according to an embodiment of the present invention includes:

A transmitter for irradiating a laser beam; A mirror scanner repeatedly rotating in a predetermined angle range such that the laser beam irradiated from the transmitter is reflected in various directions; A mirror that irradiates a laser beam reflected from the mirror scanner to a target object and receives a laser beam reflected from the target object; A receiving unit for receiving the laser beam reflected by the polyhedral mirror; And a rotating motor for rotating the multi-faced mirror.

In the Lada scanning apparatus according to the embodiment of the present invention, the mirror scanner may be an actuator-based mirror scanner repeatedly driven in a predetermined angle range.

In the Lada scanning apparatus according to an embodiment of the present invention, the mirror scanner may be any one of a resonant scanner, a MEMS mirror, a voice coil motor (VCM), and an optical phase array.

In the ladder scanning device according to the embodiment of the present invention, the multi-faceted mirror may include a plurality of reflective mirrors having different slopes.

In the ladder scanning device according to the embodiment of the present invention, the plurality of reflection mirrors may partially overlap the measurement heights of the plurality of reflection mirrors.

In the Ridas scanning apparatus according to the embodiment of the present invention, the receiving unit may be a single channel receiving unit of a single pixel or a multi-channel receiving unit of N × 1 pixels.

The laser scanning apparatus according to an embodiment of the present invention is characterized in that the receiving unit is a single channel receiving unit and the receiving unit further includes a condensing lens for condensing a laser beam reflected from the multi- And the transmitting unit, the receiving unit, and the mirror scanner are synchronized with each other and can measure the measured altitude using the reflection angle of the mirror scanner.

Other specific embodiments of various aspects of the present invention are included in the detailed description below.

According to an embodiment of the present invention,

Since the multi-facet mirror is rotated by the rotating motor, the laser beam can be radiated with a wide front angle, so that the measurement range in the horizontal direction can be widened.

In addition, since the laser scanner reflects the laser beam to various vertical axis positions of the multi-faceted mirror while repeatedly driving the mirror scanner in a predetermined angle range, the measurement height in the vertical direction can be increased.

Further, since the rotary motor rotates only the multi-faced mirror and the other components are not rotated by the rotary motor, the durability of the Lada scanning device can be improved.

In addition, since the laser beam can be transmitted from the transmitting unit to the mirror scanner at a frequency of several hundred kHz or more, scanning can be performed at high speed in the vertical direction.

In addition, since a single laser diode can be used and a high-speed scanning can be performed by a single-channel receiving unit or an Nxl multi-channel receiving unit, the configuration can be simplified and manufacturing costs can be reduced.

1 is a perspective view showing a conventional Lada scanning apparatus.
2 is a view showing a measurement area of the Lada scanning device of FIG.
FIG. 3 is a diagram illustrating a prior art Ridas scanning device.
4 is a view showing a measurement area of the Lada scanning device of FIG.
5 is a diagram illustrating a Lada scanning apparatus according to an exemplary embodiment of the present invention.
FIG. 6 is a view illustrating an example of a mirror scanner of a Lada scanning apparatus according to an exemplary embodiment of the present invention. Referring to FIG.
FIG. 7 is a plan view illustrating an operating state of the Lada scanning apparatus according to an exemplary embodiment of the present invention. Referring to FIG.
8 is a view for explaining a measurement height in the case where the reflection mirrors of the multi-faceted mirror are formed at different slopes.
FIGS. 9 and 10 are views illustrating an operation of the Lada scanning apparatus according to an exemplary embodiment of the present invention. Referring to FIG.
11 to 13 are views showing a measurement area of the Lada scanning device according to an embodiment of the present invention.

The present invention is capable of various modifications and various embodiments and is intended to illustrate and describe the specific embodiments in detail. It is to be understood, however, that the invention is not to be limited to the specific embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present invention, terms such as "comprises" or "having" are used to designate the presence of stated features, integers, steps, operations, elements, components, or combinations thereof, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof. Hereinafter, a Ridas scanning apparatus according to an embodiment of the present invention will be described with reference to the drawings.

5 is a diagram illustrating a Lada scanning apparatus according to an exemplary embodiment of the present invention.

5, a Lada scanning apparatus according to an exemplary embodiment of the present invention includes a transmitter 100, a mirror scanner 200, a multi-faceted mirror 300, a receiver 400, and a rotary motor 500 .

The transmitting unit 100 is formed at a predetermined distance from the top of the mirror scanner 200, and irradiates the laser scanner 200 with the laser beam. The transmitter 100 may be, for example, a laser diode (LD) and may be a single unit.

The mirror scanner 200 is spaced apart from the transmitting unit 100 for irradiating the laser beam to a predetermined distance and reflects the laser beam irradiated from the transmitting unit 100 toward the multi-

The mirror scanner 200 is repeatedly driven in a predetermined angle range so that the laser beam irradiated from the transmitter 100 is reflected in various directions. Here, the repetitive driving may be, for example, that the mirror scanner rotates in a certain angle range. The mirror scanner 200 may rotate the laser beam so as to be reflected in a plurality of horizontal directions. However, since the horizontal direction is scanned by the rotation of the multi-faceted mirror 300, it is preferable that the mirror scanner 200 rotates so as to be reflected in a plurality of vertical directions.

This mirror scanner 200 may be, for example, a miniature actuator based mirror scanner. Examples of small actuator-based mirror scanners include resonant scanners, MEMS mirrors, voice coil motors (VCMs), and optical phase arrays.

FIG. 6 is a view illustrating an example of a mirror scanner of a Lada scanning apparatus according to an exemplary embodiment of the present invention. Referring to FIG.

6, the mirror scanner 200 includes a pair of permanent magnets 210, an electromagnet mirror 220 disposed between the pair of permanent magnets, and a rotary shaft of the electromagnet mirror (Not shown). A coil is formed in the electromagnet mirror 220. The magnetic field relationship between the permanent magnet 210 and the electromagnet mirror 220 changes according to the change of the current flowing through the coil. And reflects the laser beam irradiated from the transmitter 100 in a plurality of vertical directions while rotating the torsion bar 230 in a predetermined angle range with the rotation axis.

Since the transmitting unit 100, the receiving unit 400 and the mirror scanner 200 are not parts rotated by the rotating motor 500, the laser diode constituting the transmitting unit 100 is preferably a laser diode of several hundreds kHz or more The laser scanner 200 can transmit the laser beam at high speed and the mirror scanner 200 can reflect the laser beam to the mirror 300 to perform high-speed scanning on the object.

It is important to detect obstacles such as roads, vehicles, and people in front of a mobile platform whose main purpose is to detect obstacles while driving. Accordingly, it is more important to measure the vertical direction in a relatively narrow range than the drone or the unmanned aerial vehicle at high speed. Therefore, it is desirable to use a small actuator-based mirror scanner 200 for high-speed vertical measurement. Of course, if necessary, the driving range of the mirror scanner 200 may be widened for wider vertical high-speed measurement.

At least one collimating lens C1 may be formed between the transmitting unit 100 and the mirror scanner 200. [ The collimating lens C1 is an optical lens for condensing the laser beam generated by the laser diode constituting the transmitting unit 100. [

The multi-facet mirror 300 irradiates the laser beam reflected from the mirror scanner 200 and receives the reflected laser beam from the object. The multi-faceted mirror 300 is formed of a predetermined number (n) of reflecting mirrors. For example, the multi-facet mirror 300 may be formed of four reflective mirrors, and each of the reflective mirrors performs a reflective mirror function of reflecting the laser beam reflected by the mirror scanner 200 and irradiating the laser beam in the horizontal and vertical directions do.

FIG. 7 is a plan view showing an operation state of the Lada scanning apparatus according to an embodiment of the present invention, and FIG. 8 is a diagram illustrating a measured altitude when each of the reflection mirrors of the multi-faceted mirror is formed at different slopes.

7, when the multi-facet mirror 300 is rotated by the rotation of the rotating motor 500, the laser beam irradiated by the transmitter 100 and reflected by the mirror scanner 200 is reflected by the multi- And is forwarded at a predetermined angle. As shown in FIG. 7C, the laser beam reflected toward the mirror scanner 200 in accordance with the rotation of the multi-faceted mirror 300 is subjected to noise processing.

The higher the number of mirrors of the multi-faceted mirror 300, the higher the resolution or the higher measurement speed can be achieved. For example, when the multi-faceted mirror 300 is configured with four reflective mirrors as shown in FIG. 5, by irradiating a laser beam reflected from the mirror scanner 200 with slightly different measurement start points for the four reflective mirrors, The resolution is quadrupled, and when the laser beam is irradiated with the same measurement start point for the four reflection mirrors, the measurement speed for the object is quadrupled. Here, the number of other measurement start points is equal to the number of mirrors (n), and the positions of other start points can be moved by 1 / n of the horizontal angle resolution of the system when measured at the same starting point.

On the other hand, each of the reflection mirrors constituting the polyhedral mirror 300 can have different slopes. Here, the inclination of the reflecting mirror means an angle (?) Formed by a reflecting mirror and a vertical plane perpendicular to the bottom surface of the multi-faceted mirror.

The laser beam reflected by the mirror scanner 200 can be reflected by a plurality of reflection mirrors having different slopes and can measure various measurement heights. For example, as shown in FIG. 8, when there are four reflection mirrors having different slopes, four measurement heights H1 to H4 can be measured each time the polyhedral mirror 300 makes one revolution.

The receiving unit 400 receives the laser beam reflected by the multi-faceted mirror 300. The receiving unit 400 may be a multi-channel receiving unit having N × 1 pixels or a single-channel receiving unit including one pixel.

9 and 10 are diagrams illustrating an operation procedure of the Lada scanning apparatus according to an exemplary embodiment of the present invention, and are views for explaining a reception position in the receiver 400. FIG. 9 and 10, the receiving unit 400 exemplifies an N × 1 multi-channel receiving unit.

As shown in FIG. 9, the laser beam reflected by the mirror scanner 200 is irradiated to the lowest-altitude multi-facet mirror 300, reflected by the object, and then reflected by the mirror 300 to be reflected by the multi- (Pixels) of the multi-channel receiver 400 according to the geometric optics.

On the contrary, when the laser beam is irradiated to the mirror 300 having the highest altitude, reflected by the object, reflected by the mirror 300, and received by the multi-channel receiver 400 as shown in FIG. 10 And is received at the lowermost channel of the channel receiving unit 400. [

As described above, the position where the laser beam is irradiated to the multi-faceted mirror 300 and the position received by the multi-channel receiving unit 400 are opposite to each other.

The N × 1 multi-channel receiver 400 may be used. However, the present invention is not limited to this, and the receiver 400 may be a single-channel receiver. have. In this case, the receiving unit 400 further includes a condensing lens C2 for condensing the laser beam reflected by the polyhedral mirror 300, and the laser beam received at all measurement heights To be received on one channel (pixel).

At this time, the laser beam is transmitted in the form of a pulse in the transmitter 100, and the time for transmitting the laser beam is synchronized with the time for receiving the laser beam from the receiver 400, and the reflection angle of the mirror scanner 200 The driving signal feedback can be used to determine the measurement and the altitude. Then, the position and shape of the object are measured using the time difference of the laser beam measured at each angle.

Meanwhile, the condenser lens C2 may be applied not only to the single channel receiver but also to the Nxl multi-channel receiver 400. [

Next, the operation of the Lada scanning apparatus according to an embodiment of the present invention will be described.

First, a laser beam is transmitted from the transmission unit 100 to the mirror scanner 200. The laser beam may have various shapes such as a pulse wave, a continuous wave,

The mirror scanner 200 reflects the laser beam irradiated from the transmission unit 100 toward the multi-faceted mirror 300. The mirror scanner 200 reflects the laser beam to various vertical positions of the multi-faceted mirror 300 while being repeatedly driven in a predetermined angular range.

The multi-facet mirror 300 irradiates the laser beam reflected by the mirror scanner 200 toward the forward direction with the incident angle / reflection angle principle. The multi-faced mirror 300 can be rotated by the rotating motor 500 to irradiate the laser beam with a wide front angle. For example, when the multi-faceted mirror 300 is composed of four reflective mirrors, the measurement angle in the horizontal direction may be 140 degrees or more.

The reflection mirror constituting the multiple mirror 300 may have a constant slope or may be formed to be different from each other.

When the inclination of each surface of the reflection mirror is constant, the measurement speed or resolution of the object can be increased. That is, as shown in FIG. 11, when the number of reflection mirrors constituting the polyhedral mirror 300 is four, the inclination is constant, and the measurement start point is different, the measurement points P1 to P4 measured by the respective reflection mirrors, It is possible to increase the horizontal axis measurement resolution with respect to the object, and when the measurement start point is the same, the same measurement point is measured four times in one rotation, so that the measurement speed can be increased.

When the slopes of the respective surfaces of the reflection mirror are different, the resolution is relatively low, but the object can be measured at a wide measurement height. Namely, as shown in FIG. 12, when the number of reflection mirrors constituting the multi-faceted mirror 300 is four and the inclination is different, each time the multi-faceted mirror 300 makes one revolution, four measured heights H1 to H4 ) Can be measured.

On the other hand, even when the slopes of the respective surfaces of the reflection mirror are different, the resolution can be increased while measuring the object with a wide measurement height by designing the slopes of the respective surfaces such that the measurement altitudes partially overlap. That is, as shown in FIG. 13, the measurement speed or resolution for the target object can be increased as in the case where the inclination of each surface of the reflection mirror is constant in the overlapped measurement height portion (D).

According to the above-described Ridas scanning apparatus, since the multi-faced mirror is rotated by the rotating motor and can irradiate the laser beam with a wide front angle, the measurement range in the horizontal direction can be widened.

In addition, since the laser scanner reflects the laser beam to various vertical axis positions of the multi-faceted mirror while repeatedly driving the mirror scanner in a predetermined angle range, the measurement height in the vertical direction can be increased.

Further, since the rotary motor rotates only the multi-faced mirror and the other components are not rotated by the rotary motor, the durability of the Lada scanning device can be improved.

In addition, since the laser beam can be transmitted from the transmitting unit to the mirror scanner at a frequency of several hundred kHz or more, scanning can be performed at high speed in the vertical direction.

In addition, since a single laser diode can be used and a high-speed scanning can be performed by a single-channel receiving unit or an Nxl multi-channel receiving unit, the configuration can be simplified and manufacturing costs can be reduced.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit of the invention as set forth in the appended claims. The present invention can be variously modified and changed by those skilled in the art, and it is also within the scope of the present invention.

100: transmitting unit 200: mirror scanner
300: multiple mirror 400:
500: Rotary motor

Claims (7)

A transmitter for irradiating a laser beam;
A mirror scanner repeatedly rotating in a predetermined angle range such that the laser beam irradiated from the transmitter is reflected in various directions;
A mirror that irradiates a laser beam reflected from the mirror scanner to a target object and receives a laser beam reflected from the target object;
A receiving unit for receiving the laser beam reflected by the polyhedral mirror;
A rotating motor for rotating the multi-faceted mirror;
And a scanning unit.
The apparatus according to claim 1,
Wherein the actuator is an actuator-based mirror scanner that is repeatedly driven in a predetermined angle range.
The image scanner according to claim 2,
A resonance scanner, a MEMS mirror, a voice coil motor (VCM), and an optical phase array.
The multi-faceted mirror according to claim 1,
And a plurality of reflection mirrors whose slopes are different from each other.
5. The image display device according to claim 4,
And the measured altitudes of the plurality of reflection mirrors partially overlap each other.
The apparatus of claim 1,
A single-channel receiving unit having a single pixel, or a multi-channel receiving unit having N × 1 pixels arranged therein.
The method of claim 6,
Wherein the receiver is a single channel receiver,
Wherein the receiving unit further includes a condenser lens for condensing the laser beam reflected by the polyhedral mirror,
Wherein the transmitter, the receiver, and the mirror scanner are synchronized to measure a measurement altitude using a reflection angle of the mirror scanner.

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