KR20230123800A - Lidar apparatus compensating for angular resolution deviation and operating method thereof - Google Patents

Abstract

According to various embodiments of the present invention, by applying the LIDAR device and its operating method, it is possible to scan a wide area of an angular range without performance degradation, and to measure a short range within several meters. In addition, by applying the lidar device and its operating method, it is possible to have a uniform angular resolution from the edge to the center of the scan range by correcting the angular resolution.

Description

LIDAR device for correcting angular resolution deviation and its operating method

The present invention relates to a lidar device and a method of operating the same. More specifically, it relates to a lidar device and its operating method for correcting each resolution deviation.

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 and its operating method capable of scanning a wide area of angular range without performance degradation and measuring a short range within several meters.

An object of the present invention is to provide a lidar device and a method of operating the same that can have a uniform angular resolution from the edge to the center of the scan range by correcting the angular resolution.

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; a scanning unit configured to receive and reflect the emitted first light toward the scan area, receive second light reflected from the object, and transmit the second light toward the photodetector; and calculating at least one error value generated by the scanning unit, controlling the scanning unit to operate in order to correct each resolution deviation corresponding to the calculated error value, and using a detection result of the photodetector to control the target object. It includes; a signal processing unit for acquiring distance information about.

Here, the scanning unit may include: a reflector configured to adjust a scan area in the horizontal or vertical direction by performing a tilt drive in a horizontal or vertical direction; and a drive unit connected to the reflector to drive the reflector, wherein the signal processing unit calculates the error value based on a driving range and a driving period in which the reflector performs a tilt drive.

Here, the reflector may include: a first mirror unit adjusting a vertical field of view (FOV) of the scan area by performing a tilt drive in a vertical direction; and a second mirror unit performing a tilt drive in a horizontal direction to adjust a horizontal field of view (FOV) of the scan area and performing a tilt drive in a vertical direction in response to the calculated error value. characterized by

Here, the driving unit includes a first driving unit that tilts and drives the first mirror unit in a vertical direction by combining with the driving shaft of the first mirror unit to transmit power so that the driving shaft rotates integrally with the first mirror unit; a second horizontal driving unit coupled to a horizontal driving shaft of the second mirror unit to tilt and drive the second mirror unit in a horizontal direction by transmitting power so that the horizontal driving shaft rotates integrally with the second mirror unit; And a second vertical driving unit coupled to the vertical driving shaft of the second mirror unit to tilt and drive the second mirror unit in the vertical direction by transmitting power so that the vertical driving shaft rotates integrally with the second mirror unit. characterized by

Here, the first mirror unit repeatedly tilts and drives a predetermined first driving range with a predetermined first driving cycle, and the signal processing unit performs a tilt drive based on the predetermined first driving range and the predetermined first driving cycle. A reference value serving as a criterion for correcting the deviation of each resolution of the scanning unit is calculated, and an error value is calculated based on the calculated reference value and a driving angle of the first mirror unit.

Here, the reference value calculated by the signal processing unit is a driving angle when it is assumed that the first mirror unit repeatedly linearly drives the first predetermined driving range with the first predetermined driving cycle, and the signal processing unit, The error value may be calculated by subtracting the reference value from the driving angle of the first mirror unit.

Here, the signal processing unit, based on the calculated error value, corresponds to the first predetermined driving period and the predetermined first driving range, a second driving period for tilting and driving the second mirror unit in the vertical direction. And it is characterized in that for calculating the second driving range.

Here, the second vertical driving unit may tilt and drive the second mirror unit in a vertical direction corresponding to the calculated second driving period and the calculated second driving range.

Here, a first angle sensor for measuring the driving angle of the first mirror unit and transmitting the measured angle information to the signal processing unit; and a second angle sensor for measuring the driving angle of the second mirror unit and transmitting the measured angle information to the signal processing unit.

Here, the signal processing unit controls the output of the light source and the pulse repetition rate, calculates the error value based on the transmitted angle information of the first mirror unit, and calculates the error value based on the transmitted angle information of the second mirror unit and the calculated angle information of the second mirror unit. It is characterized in that the driving angle of the second mirror unit is controlled through the driving unit using the error value.

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

A lidar device operation method performed in a lidar device including a light source, a photodetector, a scanning unit, a signal processing unit, and a driving unit according to an embodiment of the present invention for achieving the above object is, the light source, the first light releasing; receiving, by the scanning unit, the emitted first light and reflecting it toward the scan area, receiving a second light reflected from the object, and 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 controlling the signal processing unit to calculate at least one error value generated by the scanning unit, to drive the scanning unit to compensate for each resolution deviation corresponding to the calculated error value, and to control the detection result of the photodetector. and acquiring distance information about the target object using .

As described above, according to an embodiment of the present invention, by applying the LIDAR device and its operating method, it is possible to scan a wide range of angles without performance degradation, and to measure a short range within several meters. .

In addition, according to one embodiment of the present invention, by applying the lidar device and its operating method, it is possible to have a uniform angular resolution from the edge to the center of the scan range by correcting the angular resolution.

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 adjusting unit of a lidar device according to an embodiment of the present invention.
6 is a diagram for explaining problems according to vertical scan driving of a conventional lidar device.
7 is a diagram for explaining problems caused by vertical scan driving and horizontal scan driving of a conventional lidar device.
8 is a diagram for explaining an operation process of a first mirror unit and a second mirror unit of a lidar device according to an embodiment of the present invention.
9 is a diagram for explaining a method of calculating an error value of a lidar device according to an embodiment of the present invention.
10 is a diagram for explaining vertical scan driving of a lidar device according to an embodiment of the present invention according to the error value calculation method described with reference to FIG. 9 .
11 is a diagram for explaining vertical scan driving and horizontal scan driving of a lidar device according to an embodiment of the present invention according to the error value calculation method described with reference to FIG. 9 .
12 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 of achieving them, will become clear with reference to the detailed description of the following embodiments taken 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 common knowledge in the art to which the present invention belongs. It is provided to completely inform the person who has 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 apparatus 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 one 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, an optical axis may mean 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 detail with reference to FIGS. 3 to 5 .

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 may be 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 .

The signal processing unit 400 may calculate at least one error value for correcting each resolution deviation of the scanning unit 200 and control the scanning unit 200 to operate in response to the calculated error value.

Here, the error value may be a value for each resolution deviation that occurs while the scanning unit 200 is driven to reflect the first light L1 toward the scan area.

A process in which the signal processing unit 400 calculates an error value for correcting each resolution deviation will be described in detail with reference to FIG. 9 .

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 can control the output and pulse repetition rate of the light source 100, and control the tilt driving angles of the first mirror unit 241 and the second mirror unit 242, which will be described later. can 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 value, the signal processing unit 400 determines the signal intensity of the transmitted first light L1 and 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 the first 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 to 2 are not essential components, and some blocks connected to the lidar device 10 in another embodiment may be added, changed, or deleted.

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

3 to 4, the lidar device 10 further includes a driving unit 250, a first angle sensor 810, a second angle sensor 820, an optical window 500 and a display unit 700. can include

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

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 may be formed of an optical lens so that the first light L1 output from the beam transmission optical fiber of the light source 100 becomes parallel light.

The scanning unit 200 may include a receiving member 230 that collects 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 may be formed of an optical lens to focus the second light L2 reflected from the object 20 and transmit it to the photodetector 300 .

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 reflects the emitted first light L1 toward the object 20, reflects the second light L2 reflected from the object 20 toward the photodetector 300, and scan area. It may include a reflector 240 configured to adjust the.

The reflector 240 may be configured to adjust a scan area in a horizontal or vertical direction by performing a tilt drive in a horizontal or vertical direction. An error value can be calculated based on the driving range and driving cycle.

The error value calculated by the signal processing unit 400 may be calculated in real time during the operation of the lidar device 10, but may be calculated in advance and stored in the signal processing unit 400 prior to the operation of the lidar device 10. there is.

The driver 250 may be connected to the reflector 240 to drive the reflector 240 in response to the calculated error value. For example, when the calculated error value is +25, the driver 250 may tilt and drive the reflector 240 by +25 degrees.

The reflector 240 tilts in the vertical direction to adjust the vertical field of view (FOV) of the scan area, and tilts in the horizontal direction to adjust the horizontal field of view of the scan area. The second mirror unit 242 may include a second mirror unit 242 that adjusts a field of view (FOV) and performs tilt driving in a vertical direction in response to the calculated error value.

According to one embodiment of the present invention, the driving unit 250 may include a first driving unit (not shown) and a second driving unit (not shown).

The first driver may tilt and drive the first mirror unit 241 in the vertical direction. More specifically, the first tilting unit included in the first driving unit is combined with a driving shaft (not shown) of the first mirror unit 241 to transfer power so that the driving shaft rotates integrally with the first mirror unit 241. Thus, the first mirror unit 241 may be tilted and driven in the vertical direction.

The second driving unit may include a second vertical driving unit and a second horizontal driving unit.

The second horizontal driver may tilt and drive the second mirror unit 242 in the horizontal direction. More specifically, the second horizontal tilting unit included in the second horizontal driving unit is coupled with a horizontal driving shaft (not shown) of the second mirror unit 242 to rotate the horizontal driving shaft integrally with the second mirror unit 242. It is possible to tilt and drive the second mirror unit 242 in the horizontal direction in a manner of transmitting the .

The second vertical driver may tilt and drive the second mirror unit 242 in the vertical direction. More specifically, the second vertical tilting unit included in the second vertical driving unit is combined with the vertical driving shaft (not shown) of the second mirror unit 242 to generate an error value calculated by the signal processing unit 400 or pre-calculated by the signal processing unit. In response to the error value stored in 400 , the second mirror unit 242 may be tilted and driven in the vertical direction by transmitting power so that the vertical driving shaft rotates integrally with the second mirror unit 242 .

Since the second horizontal driving unit and the second vertical driving unit do not affect each other during operation, the second horizontal driving unit and the second vertical driving unit operate simultaneously to drive the second mirror unit 242 in the horizontal and vertical directions, respectively. However, it is not necessarily limited thereto and may operate sequentially.

According to an embodiment of the present invention, the first mirror unit 241 and the second mirror unit 242 may be MEMS (Micro Electro Mechanical Systems) mirrors.

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 a horizontal or vertical direction to scan a horizontal or vertical field of view (FOV), and the scanning angle range of the lidar device 10 may be determined according to the driving angle of the MEMS mirror.

The first mirror unit 241 may tilt and drive repeatedly in a first predetermined driving range (eg, -45 degrees to 45 degrees) with a first predetermined driving period (eg, 10 ms).

The signal processing unit 400 calculates a reference value that is a reference value for correcting each resolution deviation of the scanning unit 200 based on a first predetermined driving range and a predetermined first driving cycle of the first mirror unit 241, and calculates the reference value. An error value may be calculated based on the reference value and the driving angle of the first mirror unit 241 .

Here, the reference value may be a driving angle when it is assumed that the first mirror unit 241 is repeatedly linearly driven in a predetermined first driving range with a predetermined first driving period.

The signal processing unit 400 may calculate an error value by subtracting a reference value from the driving angle of the first mirror unit 241 . For example, when the driving angle of the first mirror unit 241 is 35 degrees and the reference value is 22.5 degrees, the error value may be 12.5 degrees.

The first angle sensor 810 may measure the driving angle of the first mirror unit 241 and transmit the measured angle information to the signal processing unit 400 .

The second angle sensor 820 may measure the driving angle of the second mirror unit 242 and transmit the measured angle information to the signal processing unit 400 .

The signal processor 400 may receive driving angles of the first mirror unit 241 and the second mirror unit 242 using the first angle sensor 810 and the second angle sensor 820 .

The signal processing unit 400 controls the output and pulse repetition rate of the light source 100, calculates an error value based on the transmitted angle information of the first mirror unit 241, and calculates the error value of the transmitted second mirror unit 242. The driving angle of the second mirror unit 242 may be adjusted through the driving unit 250 using the angle information and the calculated error value. For example, when the driving angle of the first mirror unit 241 is 35 degrees and the reference value is 22.5 degrees, so the error value is 12.5 degrees, the signal processing unit 400 uses the driving unit 250 to perform the second mirror unit 242 ) can be tilt driven by 12.5 degrees.

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 display unit 700 may display 3D object image information output from the LIDAR system 10 .

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 to 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 view for explaining an optical axis adjusting 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 may be located at the center of the optical axis adjuster 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 μm.

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 these materials 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 reflectivity 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 the angle of the 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) Since is always constant, the photodetector 300 connected to an optical fiber (eg, a single element photodetector connected to an optical fiber) can be used.

6 is a diagram for explaining problems according to vertical scan driving of a conventional lidar device.

Referring to FIG. 6 , since the first mirror unit 241 performs a tilt drive in the vertical direction rather than a linear drive, the vertical interval between scanning points according to the tilt drive of the first mirror unit 241 is not constant and uneven. You can check.

More specifically, in the vertical direction of the scan area, an angular resolution deviation occurs between the edge and the center, and the vertical interval between scanning points becomes longer from the upper edge toward the center and shorter from the center to the lower edge. . As the center is scanned more densely than the edges, angular resolution deviations occur.

7 is a diagram for explaining problems caused by vertical scan driving and horizontal scan driving of a conventional lidar device.

Referring to FIG. 7 , since the first mirror unit 241 performs tilt driving in the vertical direction rather than linear driving, vertical intervals between scanning points according to the tilt driving of the first mirror unit 241 are not constant and uneven. You can check. In addition, as the second mirror unit 242 tilts in the horizontal direction, it can be confirmed that vertical intervals between scanning points are not constant and uneven throughout the scan area.

As shown in FIGS. 6 and 7, in the conventional lidar device, a laser beam is reflected on a MEMS mirror to scan in a vertical direction. Since the driving angle of the MEMS mirror over time has a non-linearity, the edges and the center when the MEMS mirror is driven Since angular resolution deviation occurs in the vertical direction of , there is a problem that angular resolution is lowered.

8 is a diagram for explaining an operation process of a first mirror unit and a second mirror unit of a lidar device according to an embodiment of the present invention.

Referring to FIG. 8 , the first mirror unit 241 may repeatedly tilt and drive a first predetermined driving range during a first predetermined driving period. As the first mirror unit 241 performs a tilt drive, each resolution deviation as confirmed in FIGS. 6 to 7 occurs, and the second mirror unit 242 generates As the vertical compensation tilt drive for correcting the vertical angle deviation is performed, the angular resolution of the lidar device 10 may be corrected to be uniform.

① in FIG. 8 indicates that the first mirror unit 241 is tilted by +30 degrees. ② indicates that the first mirror unit 241 is tilt-driven by 0 degree. ③ indicates that the first mirror unit 241 is tilted by -30 degrees.

ⓑ indicates that the second mirror unit 242 is in a tilt-driven state by +5 degrees. ⓐ indicates that the second mirror unit 242 is tilted by 0 degrees. ⓒ indicates that the second mirror unit 242 is tilted by -5 degrees.

Referring to FIG. 8, the deviation generated as the first mirror unit 241 is sequentially tilted in the state of ①->②->③ is the second mirror unit 242 ⓐ->ⓑ->ⓐ-> It can be corrected by sequentially driving the tilt in the state of ⓒ->ⓐ.

In addition, the deviation caused by sequentially tilting the first mirror unit 241 in the state of ③->②->① is the second mirror unit 242 ⓐ->ⓒ->ⓐ->ⓑ->ⓐ It can be corrected by sequentially driving the tilt in this state.

The signal processing unit 400 is configured to drive the second mirror unit 242 in the vertical direction in response to the tilt-driving of the first mirror unit 241 repeatedly in the first driving range determined in advance with the first driving cycle. A second driving cycle and a second driving range may be calculated.

Correspondingly, the second vertical driving unit may tilt and drive the second mirror unit 242 in the vertical direction repeatedly in the second driving range with the second driving cycle.

Separately from this, the second horizontal driving unit repeatedly tilts the second mirror unit in a predetermined third driving range (eg, -55 degrees to 55 degrees) with a predetermined third driving period (eg, 30 ms). can make it

According to an embodiment of the present invention, the signal processing unit 400 may calculate a maximum error value, which is the largest value among at least one error value generated in the first mirror unit 241 in order to calculate the second driving range. . Also, the second driving period calculated by the signal processing unit 400 may be half of the first driving period.

For example, when the calculated maximum error value is 5 degrees and the first drive period is 10 ms, the signal processing unit 400 may determine the second drive range from -5 degrees to 5 degrees, and set the second drive period to 5 ms. can be determined by

The driving angles and driving processes of the first mirror unit 241 and the second mirror unit 242 described with reference to FIG. 8 correspond to one embodiment of the present invention and are not necessarily limited thereto.

9 is a diagram for explaining a method of calculating an error value of a lidar device according to an embodiment of the present invention.

9(a) shows that the first mirror unit 241 of the lidar device according to an embodiment of the present invention has a first driving range (-45 degrees to 45 degrees) at a predetermined first driving period (10 ms). ) is a graph showing the driving angle of the first mirror unit 241 measured by the first angle sensor 810 according to repeated "tilt driving (nonlinear driving)".

9(b) shows that the first mirror unit 241 of the lidar device according to an embodiment of the present invention has a first driving range (-45 degrees to 45 degrees) in a predetermined first driving period (10 ms). ), it is a graph continuously showing the driving angle of the first mirror unit 241 calculated by the signal processing unit 400 according to "linear driving".

According to an embodiment of the present invention, the reference value calculated by the signal processing unit 400 is the case where it is assumed that the first mirror unit 241 repeatedly linearly drives a predetermined first driving range with a predetermined first driving period. It may be a driving angle. For example, referring to (b) of FIG. 9 , the reference value at 1.25 ms may be 22.5 degrees, and the reference value at 10 ms may be 45 degrees.

According to an embodiment of the present invention, the error value calculated by the signal processing unit 400 may be a value obtained by subtracting the reference value from the driving angle of the first mirror unit 241 .

9(c) is a diagram showing error values calculated for each predetermined unit time interval (eg, 0.35ms) in the embodiments of FIGS. 9(a) and 9(b).

According to an embodiment of the present invention, the signal processing unit 400 may calculate an error value at a predetermined unit time interval, and control the second mirror unit 242 to be driven in response to the calculated error value.

When the signal processing unit 400 calculates the error value in real time and controls the second mirror unit 242 to be driven in response to the calculated error value, the amount of processing is increased and rather the larger error of the lidar device 10 is caused. because it may cause

9(d) is a diagram for explaining the driving direction of the second mirror unit 242 according to the error value calculated in the embodiments of FIGS. 9(a) and 9(b).

Referring to (d) of FIG. 9 , since the error value is 0 at 0 ms, 2.5 ms, 5 ms, 7.5 ms, and 10 ms, the signal processing unit 400 controls the second mirror unit 242 to be at 0 degree.

In the interval between 0 ms and 2.5 ms, the signal processing unit 400 controls the vertical tilt driving angle of the second mirror unit 242 to have a positive value.

In the interval between 2.5 ms and 5 ms, the signal processing unit 400 controls the vertical tilt driving angle of the first mirror unit 241 to have a negative value.

In the interval between 5 ms and 7.5 ms, the signal processing unit 400 controls the vertical tilt drive angle of the second mirror unit 242 to have a negative value.

In the period between 7.5 ms and 10 ms, the signal processing unit 400 controls the vertical tilt driving angle of the second mirror unit 242 to have a positive value.

That is, in a section where the error value is positive, the vertical tilt driving range of the second mirror unit 242 is driven in a positive range (eg, 0 degrees to 45 degrees), and the error value is a negative value. The vertical tilt driving range of the second mirror unit 242 is driven in a negative range (eg, 0 degrees to -45 degrees) in a section having .

10 is a diagram for explaining vertical scan driving of a lidar device according to an embodiment of the present invention according to the error value calculation method described with reference to FIG. 9 .

Referring to FIG. 10, by tilting and driving the second mirror unit 242 in the vertical direction according to the error value calculation method described with reference to FIG. You can confirm that this appears. That is, by correcting the angular resolution, it is possible to have a uniform angular resolution from the edge to the center of the scan range.

11 is a diagram for explaining vertical scan driving and horizontal scan driving of a lidar device according to an embodiment of the present invention according to the error value calculation method described with reference to FIG. 9 .

Referring to FIG. 11 , since the second mirror unit 242 performs tilt driving in the vertical direction and tilt driving in the horizontal direction, vertical intervals between scanning points may appear constant throughout the scan area.

12 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 receives the second light L2. ) may be transmitted toward the photodetector.

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

In step S104, the signal processing unit 400 calculates an error value for correcting each resolution deviation of the scanning unit 200, and obtains distance information with respect to the object 20 using the detection result of the photodetector 300. can do.

In step S104, the driving unit 250 may be connected to the scanning unit 200 to drive the scanning unit 200 in response to the calculated error value.

In FIG. 12, 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. 12 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.

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 for the target object 20 output from the LIDAR device 10 .

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 above-described control unit may be implemented as 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 source or a rechargeable power supply device, thereby including 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. In addition, although all of the components may be implemented as a single independent piece of hardware, some or all of the components are selectively combined to perform some or all of the combined functions in one or a plurality of pieces of hardware. It may be implemented as a computer program having. In addition, such a computer program may implement an embodiment of the present invention by being stored in a computer readable medium such as a USB memory, a CD disk, or a flash memory and read and executed by a computer. A recording medium of a computer program may include a magnetic recording medium, an optical recording medium, and the like.

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.

10: lidar device
20: object
100: light source
200: scanning unit
210: transmission member
220: optical axis adjustment unit
230: receiving member
240: reflector
241: first mirror unit
242: second mirror unit
250: driving unit
300: photodetector
400: signal processing unit
500: optical window
700: display unit
810: first angle sensor
820: second angle sensor

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;
a scanning unit configured to receive and reflect the emitted first light toward the scan area, receive second light reflected from the object, and transmit the second light toward the photodetector; and
Calculate at least one error value generated by the scanning unit, control the scanning unit to operate in order to correct each resolution deviation corresponding to the calculated error value, and use the detection result of the photodetector to detect the target object. A lidar device comprising a; signal processing unit for obtaining distance information. According to claim 1,
The scanning unit,
a reflector configured to adjust a scan area in the horizontal or vertical direction by performing a tilt drive in a horizontal or vertical direction; and
A drive unit connected to the reflector to drive the reflector; includes;
The signal processing unit, LiDAR device, characterized in that for calculating the error value based on the drive range and drive period in which the reflector performs the tilt drive. According to claim 2,
the reflector,
a first mirror unit for adjusting a vertical field of view (FOV) of the scan area by performing a tilt drive in a vertical direction; and
A second mirror unit performing tilt driving in the horizontal direction to adjust the horizontal field of view (FOV) of the scan area and performing tilt driving in the vertical direction in response to the calculated error value; Lidar device characterized. According to claim 3,
the driving unit,
a first driving unit coupled to a driving shaft of the first mirror unit to tilt and drive the first mirror unit in a vertical direction by transmitting power so that the driving shaft rotates integrally with the first mirror unit;
a second horizontal driving unit coupled to a horizontal driving shaft of the second mirror unit to tilt and drive the second mirror unit in a horizontal direction by transmitting power so that the horizontal driving shaft rotates integrally with the second mirror unit; and
A second vertical driving unit coupled to the vertical driving shaft of the second mirror unit to tilt and drive the second mirror unit in the vertical direction by transmitting power so that the vertical driving shaft rotates integrally with the second mirror unit. Lidar device characterized. According to claim 4,
The first mirror unit,
Tilt driving a predetermined first driving range repeatedly with a predetermined first driving cycle;
The signal processing unit,
Based on the first predetermined driving range and the first predetermined driving cycle, a reference value serving as a basis for correcting the deviation of each resolution of the scanning unit is calculated, and an error based on the calculated reference value and the driving angle of the first mirror unit is calculated. Lidar device, characterized in that for calculating the value. According to claim 5,
The reference value calculated by the signal processing unit is,
A driving angle when it is assumed that the first mirror unit repeatedly linearly drives the first predetermined driving range at the first predetermined driving cycle;
The signal processing unit, LiDAR device, characterized in that for calculating the error value by subtracting the reference value from the driving angle of the first mirror unit. According to claim 6,
The signal processing unit,
Based on the calculated error value, a second driving period and a second driving range for tilt-driving the second mirror unit in the vertical direction are calculated corresponding to the first driving period and the first driving range. Lidar device, characterized in that for doing. According to claim 7,
The second vertical driving unit,
LiDAR device, characterized in that for tilting and driving the second mirror unit in the vertical direction corresponding to the calculated second driving period and the calculated second driving range. According to claim 3,
a first angle sensor for measuring a driving angle of the first mirror unit and transmitting the measured angle information to the signal processing unit; and
A lidar device comprising a; second angle sensor for measuring the driving angle of the second mirror unit and transmitting the measured angle information to the signal processing unit. According to claim 9,
The signal processing unit,
The driving unit controls the output of the light source and the pulse repetition rate, calculates the error value based on the transmitted angle information of the first mirror unit, and uses the transmitted angle information of the second mirror unit and the calculated error value. LIDAR device, characterized in that for controlling the driving angle of the second mirror unit through. 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 11,
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, a signal processing unit and a driving unit,
the light source emitting a first light;
receiving, by the scanning unit, the emitted first light and reflecting it toward the scan area, receiving a second light reflected from the object, and 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
The signal processing unit calculates at least one error value generated in the scanning unit, controls the scanning unit to operate in order to correct each resolution deviation corresponding to the calculated error value, and outputs a detection result of the photodetector. A method of operating a lidar device comprising the steps of obtaining distance information on the object by using a method.

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