KR20230116366A - Lidar apparatus using optical axis adjustment optical system and operating method thereof - Google Patents

Abstract

According to the present invention, a light source for emitting a first light; a photodetector for detecting second light, which is light reflected by an object positioned on a scan area, among the first light; The emitted first light is received and reflected toward the scan area, the second light reflected from the object is received, and the optical axis of the first light and the optical axis of the second light are adjusted to be the same, so that the second light a scanning unit that transmits a ? to the photodetector; and a signal processor configured to obtain distance information on the target object by using a detection result of the photodetector.
According to various embodiments of the present invention, by applying a LIDAR device using an optical axis adjustment optical system, it is possible to scan a wide area of an angular range without degrading performance, and it is possible to measure a short range within several meters.

Description

LIDAR device using an optical axis adjustment optical system and its operating method

The present invention relates to a lidar device and a method of operating the same.

The contents described in this part merely provide background information on the present embodiment and do not constitute prior art.

LIDAR (Light Detection and Ranging) irradiates light, for example, laser, on an object and analyzes the light reflected from the object to determine the physical properties of the object, such as distance, direction, speed, temperature, material distribution and concentration characteristics, etc. It is one of the remote detection devices that can be measured. LIDAR can measure the physical properties of an object more precisely by taking advantage of lasers that can generate pulse signals with high energy density and short cycles.

LIDAR uses a laser light source of a specific wavelength or a laser light source capable of tunable wavelength as a light source and is used in various fields such as 3D image acquisition, weather observation, speed or distance measurement of a subject, and autonomous driving. For example, LIDAR is mounted on airplanes and satellites and used for precise atmospheric analysis and global environment observation.

In addition, on the ground, lidar sensor technologies in a simple form for long-distance measurement, vehicle speed violation enforcement, etc. are being commercialized. Recently, it is used as a laser scanner or 3D image camera and is used for 3D reverse engineering or unmanned vehicles.

Republic of Korea Patent Registration No. 10-2299264 (2021.09.01.) Republic of Korea Patent Registration No. 10-2263182 (2021.06.03.)

An object of the present invention is to provide a lidar device capable of scanning a wide area of an angular range without performance degradation and measuring a short range within several meters.

Other non-specified objects of the present invention may be additionally considered within the scope that can be easily inferred from the following detailed description and effects thereof.

LiDAR device according to an embodiment of the present invention for achieving the above object, a light source for emitting a first light; a photodetector for detecting second light, which is light reflected by an object positioned on a scan area, among the first light; The emitted first light is received and reflected toward the scan area, the second light reflected from the object is received, and the optical axis of the first light and the optical axis of the second light are adjusted to be the same, so that the second light a scanning unit that transmits a ? to the photodetector; and a signal processor configured to obtain distance information about the target object by using a detection result of the photodetector.

Here, the scanning unit may include: a transmitting member that adjusts the first light incident from the light source to become parallel light; It includes at least one hole and a reflective surface surrounding the hole, and adjusts optical axes of the first light and the second light to be the same by passing the first light through the hole, an optical axis adjusting unit that reflects the second light using a reflective surface; and a receiving member for condensing the second light reflected from the reflective surface and incident it to the photodetector.

Here, the scanning unit may include: a reflecting unit configured to reflect the first light passing through the hole toward the target object, reflect the second light reflected from the target object toward the optical axis adjusting unit, and adjust a scan area; and a driving unit connected to the reflecting unit and driving the reflecting unit.

Here, the reflector may include: a first mirror unit for adjusting a vertical field of view (FOV) of the scan area; and a second mirror unit for adjusting a horizontal field of view (FOV) of the scan area.

Here, the first mirror unit is a MEMS mirror, and the second mirror unit is a polygon mirror.

Here, the signal processing unit is characterized in that the scan area is adjusted by using the drive unit to tilt and drive the MEMS mirror in a vertical direction and rotate and drive the polygon mirror in a horizontal direction.

Here, it further comprises an optical window for transmitting the first light acquired by the scanning unit and reflected toward the scan area and the second light obtained by the scanning unit after being reflected from the object. do.

Here, the optical window may include: a window unit that transmits a first light acquired by the scanning unit and reflected toward the scan area and a second light obtained by the scanning unit after being reflected from the object; a frame portion providing a structure for fixing the window portion; and at least two light reflection mirrors fixed to the frame part to reflect the first light.

Here, the at least two light reflecting mirrors include a first reflecting mirror positioned at an upper edge of the frame portion; and a second reflection mirror positioned at a lower edge of the frame unit.

Here, the signal processing unit may measure the length of an optical path between the window unit and the light source using the at least two light reflecting mirrors.

Here, the signal processing unit is characterized in that the obtained distance information for the object is corrected using the measured length of the optical path.

Here, the photodetector is characterized in that it is composed of an InGaAs-based PIN type, APD type, or SPAD type.

According to an embodiment of the present invention for achieving the above object, a method for operating a lidar device performed in a lidar device including a light source, a photodetector, a scanning unit, and a signal processing unit, wherein the light source emits a first light doing; The scanning unit receives the emitted first light and reflects it toward the scan area, receives the second light reflected from the object, and adjusts the optical axis of the first light and the optical axis of the second light to be the same, transmitting the second light toward the photodetector; detecting, by the photodetector, second light, which is light reflected by an object positioned on a scan area, from among the first light; and acquiring, by the signal processing unit, distance information about the target object by using a detection result of the photodetector.

As described above, according to an embodiment of the present invention, by applying a LIDAR device using an optical axis adjustment optical system, it is possible to scan a wide range of angles without deterioration in performance, and it is possible to measure a short range within several meters. .

Even if the effects are not explicitly mentioned here, the effects described in the following specification expected by the technical features of the present invention and their provisional effects are treated as described in the specification of the present invention.

1 and 2 are diagrams for explaining a lidar device according to an embodiment of the present invention.
3 to 4 are diagrams for explaining in detail a lidar device according to an embodiment of the present invention.
5 is a view for explaining an optical axis adjustment unit of a lidar apparatus according to an embodiment of the present invention.
6 is a view for explaining an optical window of a lidar device according to an embodiment of the present invention.
7 to 9 are diagrams for explaining how a LIDAR device according to an embodiment of the present invention obtains information on an object.
10 is a diagram for explaining an operating process of a lidar device according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Advantages and features of the present invention, and methods for achieving them, will become clear with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below and may be implemented in various different forms, only the present embodiments make the disclosure of the present invention complete, and the common knowledge in the art to which the present invention belongs It is provided to fully inform the holder of the scope of the invention, and the present invention is only defined by the scope of the claims. Unless otherwise defined, all terms (including technical and scientific terms) used in this specification may be used in a meaning commonly understood by those of ordinary skill in the art to which the present invention belongs. In addition, terms defined in commonly used dictionaries are not interpreted ideally or excessively unless explicitly specifically defined.

Terms used in this application are only used to describe specific embodiments, and are not intended to limit the present invention, and singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, terms such as “has,” “can have,” “includes,” or “can include” refer to features, numbers, steps, operations, components, parts, or combinations thereof described in the specification. It should be understood that it is intended to designate the existence, but does not preclude the possibility of existence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof. Terms including ordinal numbers such as second and first may be used to describe various components, but the components are not limited by the terms.

These terms are only used for the purpose of distinguishing one component from another. For example, a second element may be termed a first element, and similarly, a first element may be termed a second element, without departing from the scope of the present invention. The terms and/or include any combination of a plurality of related recited items or any of a plurality of related recited items.

In this specification, identification codes (eg, a, b, c, etc.) for each step are used for convenience of explanation, and identification codes do not describe the order of each step, and each step is clearly Unless a specific order is specified, it may occur in a different order from the specified order. That is, each step may occur in the same order as specified, may be performed substantially simultaneously, or may be performed in the reverse order.

In addition, the term '~unit' described in this specification may mean software or a hardware component such as a field-programmable gate array (FPGA) or ASIC, and '~unit' performs certain roles. However, '~ part' is not limited to software or hardware. '~bu' may be configured to be in an addressable storage medium and may be configured to reproduce one or more processors. Therefore, as an example, '~unit' refers to components such as software components, object-oriented software components, class components, and task components, processes, functions, properties, and procedures. , subroutines, segments of program code, drivers, firmware, microcode, circuitry, data structures and variables. Functions provided within components and '~units' may be combined into smaller numbers of components and '~units' or further separated into additional components and '~units'.

Hereinafter, various embodiments of a lidar device according to the present invention will be described in detail with reference to the accompanying drawings.

The embodiments described in this specification can be widely applied in various fields, such as sensors for detecting obstacles in robots and unmanned vehicles, radar guns for measuring speed, aerial geo-mapping devices, 3D ground surveys, and underwater scanning.

1 and 2 are diagrams for explaining a lidar device according to an embodiment of the present invention.

Referring to FIGS. 1 and 2 , the LiDAR device 10 may include a light source 100 , a scanning unit 200 , an optical detector 300 and a signal processing unit 400 .

The light source 100 may be a device that emits light. For example, the light source 100 may emit light in the infrared region. When light in the infrared region is used, mixing with natural light in the visible region including sunlight can be prevented. However, it is not necessarily limited to the infrared region, and the light source 100 may emit light in various wavelength regions. In this case, correction may be required to remove mixed natural light information.

The light source 100 may emit first light L1. According to an embodiment of the present invention, the light source 100 may be a fiber laser. The optical fiber laser is preferably implemented to have the performance of a laser wavelength of 1.5 to 1.7um band, peak power of kW class, and laser pulse repetition rate of MHz class.

The scanning unit 200 receives the emitted first light L1 and reflects it toward the scan area, receives the second light L2 reflected from the object 20, and connects the first light L1 to the optical axis and The second light L2 may be transmitted toward the photodetector 300 by adjusting the optical axes of the second light L2 to be the same.

Referring to FIG. 4, adjusting the optical axis of the first light L1 and the optical axis of the second light L2 to be the same may be adjusting the optical path between the optical axis adjusting unit 220 and the object 20 to be the same. there is.

In the present invention, the optical axis preferably means a virtual line indicating an optical path through which light passes in an optical system, but is not necessarily limited thereto.

The scanning unit 200 will be described in more detail with reference to FIGS. 3 to 4 .

The photodetector 300 may detect second light L2, which is light reflected (or scattered) by the object 20 located on the scan area, among the first light L1.

The photodetector 300 may convert the second light L2 reflected or scattered by the object 20 from among the first light L1 into an electrical signal, for example, a current. The first light L1 emitted from the light source 100 may be irradiated onto the object 20 and reflected or scattered by the object 20 . Of the first light L1, the light reflected or scattered by the object 20 is referred to as the second light L2. The first light L1 and the second light L2 may have substantially the same wavelength and different intensities.

According to an embodiment of the present invention, the photodetector 300 may be a single element photodetector. Single-element photodetectors are connected by optical fibers. The laser spot focused by the receiving member 230 is focused on an optical fiber, and the optical fiber may transfer the laser beam to a single element photodetector. Here, the single element photodetector is preferably an InGaAs-based PIN type, APD type or SPAD type.

The photodetector 300 may further include a current-to-voltage conversion circuit that converts the output current into a voltage and an amplifier (not shown) that amplifies the amplitude of the voltage. In addition, the photodetector 300 may further include a filter for filtering an electric signal of a specific frequency, for example, a high pass filter.

Optical fiber-connected single-element photodetectors can receive laser signals at high speed with higher sensitivity and response speed than array-type photodetectors used in general lidars, so they can improve the resolution of 3D image information compared to general lidars.

The signal processing unit 400 may obtain distance information with respect to the object 20 by using a detection result of the photodetector 300 . The signal processing unit 400 may determine the distance from the lidar device 10 to the object 20 located on the scan area based on the detected second light L2. The signal processor 400 may calculate the distance to the object 20 based on the light emission time of the light source 100 and the light detection time of the photodetector 300 .

In addition, the signal processing unit 400 may control the operation of each component of the lidar device 10, such as the light source 100, the scanning unit 200, and the photodetector 300.

More specifically, the signal processing unit 400 may control the output and pulse repetition rate of the light source 100, and tilt driving angles of the first reflector 241 and the second reflector 242 and the camera unit, which will be described later. (600) can be controlled. The signal processor 400 may receive the second light L2 and calculate distance information of the object 20 with respect to 3D coordinates.

According to an embodiment of the present invention, the signal processing unit 400 may adjust the signal strength of the first light L1 based on the threshold and the weight.

More specifically, when the signal intensity of the second light L2 received by the photodetector 300 is lower than the first threshold, the signal processing unit 400 compares the signal intensity of the transmitted first light L1 to the first light L1. The signal strength of the first light L1 emitted by the light source 100 may be adjusted to have a signal strength equal to a value multiplied by a weight (eg, 1.3).

When the signal intensity of the second light L2 received by the photodetector 300 is greater than the first threshold and less than the second threshold, the signal processing unit 400 determines the signal intensity of the transmitted first light L1 and the second threshold. The signal strength of the first light L1 emitted by the light source 100 may be adjusted to have a signal strength obtained by multiplying 2 weights (eg, 1.1).

When the signal intensity of the second light L2 received by the photodetector 300 is greater than the second threshold, the signal processing unit 400 determines the signal intensity of the transmitted first light L1 and a third weight (for example, .

When the signal intensity of the second light L2 received by the photodetector 300 has the same value as the first threshold, the signal processing unit 400 determines the signal intensity of the transmitted first light L1 and the first weight. The first light emitted by the light source 100 to have a signal strength obtained by multiplying (eg, 1.3) and the average value (eg, 1.1) of the second weight (eg, 1.2 in the case of the above example) You can adjust the signal strength of L1).

When the signal intensity of the second light L2 received by the photodetector 300 has the same value as the second threshold, the signal processing unit 400 determines the signal intensity of the transmitted first light L1 and the second weight. The first light emitted by the light source 100 has a signal strength equal to the product of (eg, 1.1), the third weight (eg, 0.8), and the average value (0.95 in the case of the above example). The signal strength of (L1) can be adjusted.

The lidar system is being developed with the goal of wide scan angle and high resolution. However, as the scan angle widens to a wide angle, lidar system performance such as 3D image information measurement distance and spatial resolution is affected by the optical system configuration of the receiver and the performance of the laser detector. this is lowered

Existing lidar systems use an array detector to receive light at a wide scan angle or receive reflected light from a target through rotation. However, the array detector has disadvantages in that the response time is longer than that of the single element detector, so that the measurement distance is shortened and the angular resolution is lowered.

In addition, when the transmitting unit and the receiving unit are separated, the target distance cannot be measured in an area where the field of view (FOV) of the transmitting laser beam and the receiving optical system does not overlap, and there is a problem that it is impossible to measure a short distance within 1 meter. . In order to compensate for this disadvantage, a wide-angle coaxial scanning optical system in which the optical axis of the wide-angle transmission laser beam (first light L1) and the receiving laser beam (second light L2) are the same is proposed.

All blocks shown in FIGS. 1 and 2 are not essential components, and some blocks connected to the lidar device 10 may be added, changed, or deleted in another embodiment.

3 to 4 are diagrams for explaining in detail a lidar device according to an embodiment of the present invention.

Referring to FIGS. 3 and 4 , the lidar apparatus 10 may further include an optical window 500 , a camera unit 600 and a display unit 700 .

In addition, the scanning unit 200 may include a transmitting member 210, an optical axis adjusting unit 220, a receiving member 230, a reflecting unit 240, and a driving unit 250.

The scanning unit 200 may include a transmitting member 210 that adjusts the first light L1 incident from the light source 100 to become parallel light. The transmission member 210 is preferably formed of an optical lens such that the first light L1 output from the beam transmission optical fiber of the light source 100 becomes parallel light.

The scanning unit 200 includes at least one hole and a reflective surface surrounding the hole, and transmits the first light L1 and the second light L1 by using the hole. It may include an optical axis adjustment unit 220 that adjusts the optical axes of L2 to be the same and reflects the second light L2 using a reflective surface.

The optical axis adjustment unit 220 will be described in detail with reference to FIG. 5 .

The scanning unit 200 may include a receiving member 230 that condenses the second light L2 reflected from the reflective surface of the optical axis adjustment unit 220 and enters it into the photodetector 300 .

The receiving member 230 is preferably formed of an optical lens to collect the second light L2 reflected from the object 20 and pass it to the photodetector 300 .

The scanning unit 200 reflects the first light L1 passing through the hole of the optical axis adjusting unit 220 toward the target object 20, and the second light L2 reflected from the target object 20 is passed through the optical axis adjusting unit 220. ), and may include a reflector 240 configured to adjust the scan area.

The scanning unit 200 may include a driving unit 250 connected to the reflecting unit 240 to drive the reflecting unit 240 .

The reflector 240 includes a first mirror unit 241 for adjusting the vertical field of view (FOV) of the scan area and a second mirror unit 242 for adjusting the horizontal field of view (FOV) of the scan area. ) may be included.

According to an embodiment of the present invention, the first mirror unit 241 may be a Micro Electro Mechanical Systems (MEMS) mirror.

Conventional lidar optical systems have the advantage of scanning a wide area by transmitting and receiving lasers through mechanical rotation, but have a problem in mechanical durability. In order to solve this problem, a mechanical rotating part can be solved by using a MEMS mirror.

The MEMS mirror is tilted in the vertical direction to scan the vertical FOV (Field of View), and the scanning angle range of the lidar device 10 may be determined according to the driving angle of the MEMS mirror.

According to an embodiment of the present invention, the second mirror unit 242 may be a polygon mirror.

The polygon mirror rotates in the horizontal direction to scan the horizontal FOV (Field of View), and the shape of the polygon mirror is not limited to the shape shown in FIG. Accordingly, the scan angle range of the lidar device 10 may be determined.

The signal processing unit 400 may adjust the scan area by using a driving unit to tilt and drive a MEMS (Micro Electro Mechanical Systems) mirror in a vertical direction (tilt drive) and rotate and drive a polygon mirror in a horizontal direction.

The first mirror unit 241 rotates the transmitted light in a preset vertical direction (tilt driving), and the second mirror unit 242 rotates the transmitted light in a preset horizontal direction to transmit the transmitted light (first light) to the object ( 20) is sent. The transmission light may be transmitted according to a scan path of a wavy waveform (eg, a sine wave) within a predetermined scan area.

Here, the first mirror unit 241 and the second mirror unit 242 may be synchronized with each other to form a scan path. In other words, the first mirror unit 241 and the second mirror unit 242 may form a scan path of the transmission beam by adjusting angles and speeds for horizontal rotation and vertical rotation through synchronization. Here, according to the setting of the angle and speed for each of the horizontal and vertical rotations of the first mirror unit 241 and the second mirror unit 242, the scan path of the transmission beam has a size with respect to amplitude, wavelength, period, etc. can be changed.

The LiDAR device 10 generates a first light L1 obtained from the scanning unit 200 and reflected toward the scan area and a second light L2 obtained from the scanning unit 200 after being reflected from the object 20. An optical window 500 for transmission may be further included.

The optical window 500 transmits first light L1 acquired by the scanning unit 200 and reflected toward the scan area and second light L2 obtained by the scanning unit 200 after being reflected from the object 20 . A window portion 510 for making the window portion 510, a frame portion 520 providing a structure for fixing the window portion 510, and at least two light reflecting mirrors fixed to the frame portion 520 to reflect the first light L1 ( 531, 532) may be included.

The at least two light reflection mirrors include a first reflection mirror 531 positioned at an upper edge (eg, upper left edge) of the frame unit 520 and a lower edge (eg, lower right edge) of the frame unit 520. A second reflection mirror 532 located at the edge) may be included.

The at least two light reflecting mirrors are a plurality of light reflecting mirrors disposed at regular intervals on the upper portion of the frame portion 520, and the at least two light reflecting mirrors are disposed at regular intervals at the lower portion of the frame portion 520. A plurality of light reflecting mirrors may be included.

LiDAR device 10 may further include a camera unit 600 for photographing the scan area. According to an embodiment of the present invention, the camera unit 600 may be a CMOS camera.

The operator of the lidar device 10 can visually check the scan range of the lidar device 10 using a small CMOS camera. The CMOS camera may be used for the purpose of aligning (optical alignment) a line of sight (LOS) between the platform and the lidar device 10 when the lidar device 10 is mounted on a platform such as a vehicle or a drone. The FOV of the CMOS camera is preferably configured the same as the scan range of the LIDAR device 10 .

The LiDAR device 10 may further include a display unit 700 that displays the image captured by the camera unit 600 and the information of the object 20 output by the signal processing unit 400 .

The display unit 700 may display 3D object image information output from the lidar device 10 and a captured image of the camera unit 600 .

According to an embodiment of the present invention, the lidar device 10 may further include a received light amount check unit (not shown).

The received light quantity check unit measures the received light quantity at the receiving side. The received light amount confirmation unit may be implemented as a module that measures the amount of received light reflected from the object 20 in conjunction with the optical window 500 and the reflector 240, but is not limited thereto, and is interlocked with the photodetector 300. Alternatively, it may be implemented in the form of hardware included in the photodetector 300 or a program installed in the photodetector 300 .

The signal processing unit 400 compares the measured amount of received light with a predetermined reference amount of light to adjust the amount of transmitted light, the rotation angle of the reflector 240, the rotation speed of the reflector 240, and the like.

Specifically, the signal processor 400 determines the transmitted light amount, the rotation angle of the reflector 240, and the rotation speed of the reflector 240 (for example, the first mirror unit 241) when the measured received light amount is less than the reference light amount. and the driving angle and driving speed of the second mirror unit 242) may be adjusted.

The signal processing unit 400 may adjust the received light amount to be greater than or equal to the reference light amount by using one of the first adjustment value, the second adjustment value, and the third adjustment value.

The signal processing unit 400 adjusts the transmitted light quantity by applying the first adjustment value to the existing transmitted light quantity, and then updates the transmitted light quantity to the adjusted transmitted light quantity when the measured received light quantity is equal to or greater than the reference light quantity. In addition, the signal processor 400 adjusts the rotation angle of the reflector 240 by applying a second adjustment value to the rotation angle of the existing reflector 240, and when the received light amount measured is equal to or greater than the reference light amount, the reflector 240 ) can be updated to the adjusted rotation angle. In addition, the signal processing unit 400 adjusts the rotational speed of the reflecting unit 240 by applying a third adjustment value to the rotational speed of the existing reflecting unit 240, and when the measured received light amount is equal to or greater than the reference light amount, the reflector 240 ) can be updated with the adjusted rotation speed.

Meanwhile, the signal processing unit 400 determines the first adjustment value, the second adjustment value, and the third adjustment value when the measured received light quantity is less than the reference light quantity even when one of the first adjustment value, the second adjustment value, and the third adjustment value is used. The amount of received light may be adjusted to be greater than or equal to the amount of light received by sequentially applying each of the adjustment values.

For example, the signal processing unit 400 first adjusts the transmitted light amount by applying a first adjustment value, and sequentially applies the second adjustment value and the third adjustment value to adjust the rotation angle and reflection of the reflector 240 . The rotation speed of the part 240 can be adjusted. Here, the order of applying the adjustment values may be changed according to settings.

On the other hand, the signal processing unit 400 adjusts the condition with a combination of some adjustment values when the measured received light amount is less than the reference light amount even when one or all of the first adjustment value, the second adjustment value, and the third adjustment value are sequentially applied Thus, the amount of received light can be adjusted to be greater than or equal to the standard amount of light.

Specifically, the signal processing unit 400 may adjust the received light amount to be equal to or greater than the reference light amount by applying at least one of the first adjustment value, the second adjustment value, and the third adjustment value.

For example, the signal processor 400 may adjust the transmission light amount and the rotation angle of the reflector 240 by combining the first adjustment value and the second adjustment value. Here, the signal processing unit 400 may reflect and combine ratios of the first adjustment value and the second adjustment value differently. That is, the signal processing unit 400 may adjust the amount of transmitted light and the rotation angle of the reflector 240 in a combination in which different weights are assigned to the first adjustment value and the second adjustment value.

The signal processing unit 400 may modify and combine the first adjustment value, the second adjustment value, and the third adjustment value into various conditions that can be combined, and then adjust the received light quantity to be equal to or greater than the reference light quantity by applying the modified conditions.

All blocks shown in FIGS. 3 and 4 are not essential components, and in other embodiments, some blocks connected to the lidar device 10 may be added, changed, or deleted.

5 is a diagram for explaining an optical axis adjustment unit of a lidar device according to an embodiment of the present invention.

Referring to (a) of FIG. 5 , the optical axis adjuster 220 may be formed to include at least one hole 221 and a reflective surface 222 surrounding the hole 221 . The optical axis adjuster 220 adjusts the optical axes of the first light L1 and the second light L2 to be the same by passing the first light L1 through the hole 221, and the reflecting surface 222 The second light L2 may be reflected by using.

The hole 221 may pass the first light L1 and is preferably located at the center of the optical axis adjustment unit 220 .

The reflective surface 222 is preferably implemented by being coated with a material having high reflectivity for a wavelength range of 1.5 to 1.7 um.

Available materials include white resin with high reflectivity, metal and reflective paint. The white resin may include a white foamed PET material or a white POLYCARBONATE material. The reflectance of this material is about 97%, and the loss of efficiency is small because the reflection loss of light is small. As the metal, at least one selected from the group consisting of high reflectance metals such as Ag, Al, Au, Cu, Pd, Pt, Rd, and alloys thereof may be used. The reflective surface 222 may be formed by deposition. Alternatively, as the reflective paint, reflective materials such as titanium oxide (TiO ₂ ), zinc oxide (ZnO), and calcium carbonate (CaCO ₃ ) having a reflectance of 80 to 90% may be used alone or in combination. Such a reflective paint may be formed by diluting it in a solvent together with an adhesive and applying it to a material such as plastic. As an application method, it may be applied using a spray or roller.

Referring to (b) of FIG. 5 , it can be seen that the optical axes of the second light L2 incident toward the reflective surface 222 and the first light L1 passing through the hole 221 substantially coincide. .

LiDAR device 10 is a second light (L2) incident on the receiving member 230 even if the scan angle of the first light (L1) changes according to the reflector 240 (eg, MEMS mirror and polygon mirror) Since the angle of ) is always constant, it is possible to use the photodetector 300 (for example, a single element photodetector connected to an optical fiber) connected to an optical fiber.

6 is a view for explaining an optical window of a lidar device according to an embodiment of the present invention.

The optical window 500 includes a first light L1 acquired by the scanning unit 200 and reflected toward the scan area and a second light L1 obtained by the scanning unit 200 after being reflected from the object 20 ( L2) can be permeated.

The optical window 500 transmits first light L1 acquired by the scanning unit 200 and reflected toward the scan area and second light L2 obtained by the scanning unit 200 after being reflected from the object 20 . A window portion 510 for making the window portion 510, a frame portion 520 providing a structure for fixing the window portion 510, and at least two light reflecting mirrors fixed to the frame portion 520 to reflect the first light L1 ( 531, 532) may be included.

As shown in FIG. 7 , the at least two light reflection mirrors include a first reflection mirror 531 located at the upper edge of the frame part 520 and a second reflection mirror located at the lower edge of the frame part 520. (532).

The signal processing unit 400 may check scan start and end states using the first reflective mirror 531 and the second reflective mirror 532 located in the frame unit 520 .

Referring to FIG. 6 , reference numeral 540 denotes a scan path 540 of the lidar apparatus 10 according to an embodiment of the present invention. Looking at the scan path 540 , scanning starts at the first reflection mirror 531 and ends at the second reflection mirror 532 .

The frame unit 520 is a laser beam to prevent errors that may occur when the lidar device 10 scans and the first light L1 or the second light L2 is reflected by the frame unit 520 and returned. It may be formed of an absorber, or a material capable of absorbing laser may be applied.

7 to 9 are diagrams for explaining how a LIDAR device according to an embodiment of the present invention obtains information on an object.

The signal processing unit 400 may measure the length of an optical path between the window unit 510 and the light source 100 using at least two light reflecting mirrors.

The signal processing unit 400 may correct the obtained distance information about the object 20 by using the measured length of the optical path.

Referring to FIG. 7, the signal processing unit 400 of the lidar device 10 uses the first reflection mirror 531 at the 'scan start point' during a scan operation to detect the light source 100 inside the lidar device 10. A length of an optical path between the window unit 510 and the window unit 510 may be measured.

According to another embodiment of the present invention, the signal processing unit 400 of the lidar device 10 uses the second reflection mirror 532 at the 'scan end point' during the scan operation to inside the lidar device 10 A length of an optical path between the light source 100 and the window unit 510 may be measured.

The length of the optical path between the light source 100 and the window unit 510 inside the LIDAR system is the scan angle occurring inside the LIDAR device 10 when measuring the distance between the LIDAR device 10 and the target object 20. is the distance error according to

The signal processing unit 400 calculates the distance between the target object 20 and the lidar device 10 calculated using the first light L1 and the second light L2 using at least two light reflection mirrors. Distance information of the object 20 may be obtained by subtracting the length of an optical path between the light source 100 and the window unit 510 inside the LIDAR system.

The signal processing unit 400 calculates the length of the light path between the light source 100 and the window unit 510 inside the LIDAR system, which calculates the distance between the light source 100 and the first reflection mirror 531. it could be In addition, the signal processing unit 400 calculates the length of the optical path between the light source 100 and the window unit 510 inside the lidar device 10, between the light source 100 and the second reflection mirror 532. It may be to calculate the distance of

According to an embodiment of the present invention, the signal processing unit 400 calculates the length of the light path between the light source 100 and the window unit 510 inside the lidar device 10, It may be calculated using the distance between the first reflective mirror 531 and the distance between the light source 100 and the second reflective mirror 532 .

For example, the signal processing unit 400 calculates the length of the light path between the light source 100 and the window unit 510 inside the LIDAR device 10 is the light source 100 and the first reflection mirror 531 An average value of a first optical path, which is the distance between the light source 100 and the second optical path, which is the distance between the light source 100 and the second reflection mirror 532 may be obtained.

In addition, the signal processing unit 400 determines the length of an optical path between the light source 100 and the window unit 510 inside the lidar device 10 using three or more light reflection mirrors fixed to the frame unit 520. can be calculated

The distance error within the lidar device 10 according to the scan angle may be used as a distance error compensation value when calculating the distance of the 3D object 20 according to the coordinates. The distance error inside the lidar device 10 according to the scan angle can be obtained when the lidar device 10 is manufactured, and the distance error inside the lidar device 10 according to the initially obtained scan angle is driven by lidar. It can be used as a reference value for checking the state of the city lidar device 10.

Referring to FIGS. 8 to 9, the optical path inside the lidar device 10 reflected from 'at least two light reflecting mirrors' according to the scan angle of the lidar device 10 in FIG. 8 is shown in FIG. However, only the information of the object 20 may be displayed on the display unit 700.

According to another embodiment of the present invention, the lidar device 10 may further include a driving angle counting unit (not shown), and the display unit 20 includes a first lamp (not shown) and a second lamp. (not shown) may be included.

The driving angle counting unit (not shown) may calculate the sum of the driving angles of the first mirror unit 241 and the second mirror unit 242 , respectively. For example, when the first mirror unit 241 is driven by an angle of 15 degrees when driven the first time, driven by an angle of 12 degrees when driven the second time, and driven by an angle of 22 degrees when driven the third time, the driving angle counting unit (not shown) may calculate that the first mirror unit 241 is driven by a total of 49 degrees.

When the sum of the drive angles of the first mirror unit 241 calculated by the drive angle counting unit is equal to or greater than a predetermined first threshold value (eg, 50,000), the first lamp is turned on to provide the user with the first mirror unit ( 241), it may be notified that the replacement cycle of the driving member connected to the driving unit 250 has elapsed.

The second lamp turns on when the sum of the driving angles of the second mirror unit 242 calculated by the driving angle counting unit is greater than or equal to a predetermined second threshold value (eg, 70,000), and the second mirror unit 242 is turned on to inform the user of the second mirror unit ( 242), it may be notified that the replacement cycle of the driving member connected to the driving unit 250 has elapsed.

Since the first mirror unit 241 and the second mirror unit 242 inevitably frequently rotate or tilt drive in the process of operating the lidar device 10, the first mirror unit 241 and the second mirror unit ( 242) to the lidar device 10 and the drive member connected to the driving unit 250 inevitably suffer from damage and wear, which is related to the distance data of the object 20 output from the lidar device 10. may cause errors.

The lidar device 10 informs the user of the replacement cycle of the driving member connected to the driving unit 250 through the driving angle counting unit, the first lamp and the second lamp, so that the user replaces the driving member connected to the driving unit 250. By doing so, it is possible to prevent an error in distance data with respect to the object 20 output from the LIDAR device 10 .

10 is a diagram for explaining an operating process of a lidar device according to an embodiment of the present invention.

In step S101, the light source 100 may emit first light L1.

In step S102, the scanning unit 200 receives the emitted first light L1 and reflects it toward the scan area, receives the second light L2 reflected from the object 20, and The second light L2 may be transmitted toward the photodetector 300 by adjusting the optical axis of the first light L1 and the optical axis of the second light L2 to be the same.

In operation S103 , the photodetector 300 may detect second light L2 , which is light reflected by the object 20 located on the scan area, among the first light L1 .

In step S104 , the signal processing unit 400 may obtain distance information with respect to the object 20 by using the detection result of the photodetector 300 .

In FIG. 10, it is described that each process is sequentially executed, but this is merely an example, and a person skilled in the art changes and executes the sequence described in FIG. 10 without departing from the essential characteristics of the embodiment of the present invention. Alternatively, it will be possible to apply various modifications and variations by executing one or more processes in parallel or adding another process.

An operation process of the lidar device according to another embodiment of the present invention may be as follows.

The LiDAR device 10 may check the light source 100 and the scanning unit 200 by driving the reflector 240 using the driving unit.

In addition, the coordinate error may be corrected in a manner in which the signal processing unit 400 drives the reflector 240 using the driving unit.

The signal processing unit 400 may check the amount of light of the first light L1 irradiated by the light source 100 and correct the amount of light.

Subsequently, the LiDAR device 10 may acquire information of the object 20 . According to an embodiment of the present invention, the signal processing unit 400 may coordinate scan information to correspond to the shape of the window unit 510 of the optical window 500 .

Subsequently, the LIDAR device 10 may acquire the length of an optical path between the window unit 510 and the light source 100 .

Subsequently, the lidar device 10 may correct the acquired information of the object 20 using the acquired length of the optical path.

For example, the lidar device 10 calculates the actual distance from the lidar device 10 to the object 20 by calculating a value obtained by subtracting the obtained distance value of the target object 20 from the obtained distance value of the optical path. can be obtained

Subsequently, the LiDAR device 10 may display the corrected information of the object 20 .

On the other hand, although not specifically mentioned for the control unit (not shown) in the above-described embodiment, the lidar apparatus 10 according to this embodiment may further include a control unit. In that case, the control unit may be implemented to forward the received signal or the received and processed signal to an external device.

The aforementioned control unit may be implemented with at least one device selected from a logic circuit, a programming logic controller, a microcomputer, a microprocessor, and the like, and may include a communication module or be coupled to the communication module. The communication module communicates with an external device through an intranet, the Internet, a vehicle network, or the like, and may transmit signals or data related to the target object 20 or the distance to the target object 20 detected through laser scanning to the external device. This control unit can be simply mounted in the case of the lidar device (100).

On the other hand, although not shown in the drawing, the lidar device 10 may be provided with a wire or adapter or power supply means for supplying power. The power supply means may include an internal power supply or a rechargeable power supply device, and thereby may include a configuration that functions to detachably use the lidar device 10.

Even though all components constituting the embodiments of the present invention described above are described as being combined or operated as one, the present invention is not necessarily limited to these embodiments. That is, within the scope of the object of the present invention, all of the components may be selectively combined with one or more to operate.

The above description is merely an example of the technical idea of the present invention, and those skilled in the art can make various modifications, changes, and substitutions without departing from the essential characteristics of the present invention. will be. Therefore, the embodiments disclosed in the present invention and the accompanying drawings are not intended to limit the technical idea of the present invention, but to explain, and the scope of the technical idea of the present invention is not limited by these embodiments and the accompanying drawings. . The protection scope of the present invention should be construed according to the following claims, and all technical ideas within the equivalent range should be construed as being included in the scope of the present invention.

100: light source
200: scanning unit
210: transmission member
220: optical axis adjustment unit
230: receiving member
240: reflector
250: driving unit
300: photodetector
400: signal processing unit
500: optical window
600: camera unit
700: display unit
20: object

Claims (13)

a light source emitting a first light;
a photodetector for detecting second light, which is light reflected by an object positioned on a scan area, among the first light;
The emitted first light is received and reflected toward the scan area, the second light reflected from the object is received, and the optical axis of the first light and the optical axis of the second light are adjusted to be the same, so that the second light a scanning unit that transmits a ? to the photodetector; and
and a signal processing unit configured to obtain distance information on the object by using a detection result of the photodetector. According to claim 1,
The scanning unit,
a transmitting member that adjusts the first light incident from the light source to become parallel light;
It includes at least one hole and a reflective surface surrounding the hole, and adjusts optical axes of the first light and the second light to be the same by passing the first light through the hole, an optical axis adjusting unit that reflects the second light using a reflective surface; and
LiDAR device characterized in that it comprises a; receiving member for condensing the second light reflected from the reflective surface and incident to the photodetector. According to claim 2,
The scanning unit,
a reflector configured to reflect the first light passing through the hole toward the object, reflect the second light reflected from the object toward the optical axis adjuster, and adjust a scan area; and
LIDAR device, characterized in that it comprises a drive unit connected to the reflector to drive the reflector. According to claim 3,
the reflector,
a first mirror unit adjusting a vertical field of view (FOV) of the scan area; and
LiDAR device characterized in that it comprises a; second mirror unit for adjusting the horizontal field of view (FOV) of the scan area. According to claim 4,
The first mirror unit is a MEMS (Micro Electro Mechanical Systems) mirror,
The second mirror unit, lidar device, characterized in that the polygon mirror. According to claim 5,
The signal processing unit,
LIDAR device, characterized in that for adjusting the scan area by tilting and driving the MEMS mirror in a vertical direction using the drive unit, and rotationally driving the polygon mirror in a horizontal direction. According to claim 1,
and an optical window for transmitting first light acquired by the scanning unit and reflected toward the scan area and second light obtained by the scanning unit after being reflected from the object. is a device. According to claim 7,
The optical window,
a window unit configured to transmit first light acquired by the scanning unit and reflected toward the scan area and second light obtained by the scanning unit after being reflected from the object;
a frame portion providing a structure for fixing the window portion; and
LiDAR device characterized in that it comprises a; at least two light reflecting mirrors fixed to the frame portion to reflect the first light. According to claim 8,
The at least two light reflecting mirrors,
a first reflection mirror positioned at an upper edge of the frame unit; and
LiDAR device characterized in that it comprises a second reflection mirror located at the lower edge of the frame portion. According to claim 8,
The signal processing unit,
LiDAR device, characterized in that for measuring the length of the optical path between the window portion and the light source using the at least two light reflection mirrors. According to claim 10,
The signal processing unit,
LiDAR device, characterized in that for correcting the obtained distance information on the target object using the measured length of the optical path. According to claim 1,
The photodetector,
LiDAR device, characterized in that composed of an InGaAs-based PIN type, APD type or SPAD type. In the lidar device operating method performed in a lidar device including a light source, a photodetector, a scanning unit and a signal processing unit,
the light source emitting a first light;
The scanning unit receives the emitted first light and reflects it toward the scan area, receives the second light reflected from the object, and adjusts the optical axis of the first light and the optical axis of the second light to be the same, transmitting the second light toward the photodetector;
detecting, by the photodetector, second light, which is light reflected by an object positioned on a scan area, from among the first light; and
Acquiring, by the signal processing unit, distance information about the target object by using a detection result of the photodetector;

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