Patent Publication Number: US-2023133767-A1

Title: Lidar device and method for operating same

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     The present application claims priority to Korean Patent Application No. 10-2021-0150202, filed Nov. 4, 2021, the entire contents of which is incorporated herein for all purposes by this reference. 
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present disclosure relates to a LiDAR device for acquiring distance information of an object by using a laser, and a method for operating the LiDAR device. More specifically, the present disclosure relates to a LiDAR device capable of reference measurement, and a method for operating a LiDAR device capable of compensation for a detector by using reference measurement and compensation for a signal. 
     Description of the Related Art 
     A light detecting and ranging (LiDAR) device is a device for detecting a distance to an object by using a laser. In addition, the LiDAR device is a device capable of acquiring location information about things that are present nearby, by generating a point cloud using a laser. In addition, research on weather observation, 3D mapping, autonomous vehicles, autonomous drones, and unmanned robot sensors using LiDAR devices has been widely conducted. 
     The foregoing is intended merely to aid in the understanding of the background of the present disclosure, and is not intended to mean that the present disclosure falls within the purview of the related art that is already known to those skilled in the art. 
     SUMMARY OF THE INVENTION 
     The present disclosure is directed to providing a LiDAR device for calculating a distance by using reference measurement. 
     In addition, the present disclosure is directed to providing a method for operating the LiDAR device for calculating a distance by using reference measurement. 
     Technical problems to be solved by the present disclosure are not limited to the aforementioned technical problems and other technical problems which are not mentioned will be clearly understood by those skilled in the art from the present specification and the accompanying drawings. 
     According to an embodiment of the present disclosure, a LiDAR (Light Detecting and Ranging) device for measuring distance using a laser comprises: a laser emitter configured to output the laser; a scanner configured to rotate around an axis of rotation, and be located at a reference measurement position and a scan position; a detector configured to detect the laser; and a controller configured to control the laser emitter and the detector, wherein the controller comprises: a laser output controller configured to generate a trigger signal for controlling the laser emitter; and a detector controller configured to process a signal acquired from the detector and control the detector, wherein the detector controller comprises: a correction signal calculator configured to calculate a correction signal to control a voltage applied to the detector; a distance offset calculator configured to calculate a distance offset; and a distance calculator configured to calculate a distance from an object; wherein the correction signal calculator is configured to calculate the correction signal based on a first detecting signal acquired from the detector and outputted from the laser emitter and a reference signal when the scanner locates on the reference measurement position, wherein the distance offset calculator is configured to calculate offset information based on the first detecting signal acquired from the detector and outputted from the laser emitter and reference information when the scanner locates on the reference measurement position, wherein the distance calculator is configured to calculate the distance from the object based on a second detecting signal acquired in the detector and output from the laser emitter and the offset information when the scanner locates on the scan position. 
     According to an embodiment of the present disclosure, a method for operating LiDAR device for measuring distance using the laser comprises: positioning a scanner in a first reference measurement position; acquiring a first detecting signal for an outputted laser when the scanner is located on the first reference measurement position; acquiring a first compensation signal and first offset information based on the first detecting signal; changing a voltage applied to the detector to a first voltage based on the first compensation signal; positioning the scanner in a first scan position; acquiring a second detecting signal for the outputted laser when the scanner is located on the first scan position; acquiring first distance information based on first offset information and the second detecting signal; positioning the scanner in a second reference measurement position; acquiring a third detecting signal for the outputted laser when the scanner is located on the second reference measurement position; acquiring second offset information and a second compensation signal based on the third detecting signal; changing the voltage applied to the detector to a second voltage based on the second compensation signal; positioning the scanner in the second scan position; acquiring a fourth detecting signal for the outputted laser when the scanner is located on the second scan position; and acquiring the second distance information based on the fourth detecting signal and the second offset information. 
     According to an embodiment of the present disclosure, a LiDAR device comprises: a housing including an outer cover and a window; a laser emitter located in the housing, and configured to output a laser; a detector located in the housing, and configured to detect the laser; a scanner located in the housing, and configured to rotate around an axis of rotation in order to change a flight path of the laser output from the laser emitter; and a fixed mirror located in the housing, and configured to reflect the laser output from the laser emitter and reflected from the scanner when the scanner is in a first position, wherein when viewed from the top of the LiDAR device, the window may be formed extending from a first window end to a second window end, and when viewed from the top of the LiDAR device, the fixed mirror may be formed extending from a first mirror end to a second mirror end, and when viewed from the top of the LiDAR device, a first virtual line connecting the axis of rotation and the first window end and a second virtual line connecting the axis of rotation and the second window end may form a first angle in the direction of the window, and when viewed from the top of the LiDAR device, a third virtual line connecting the axis of rotation and the first mirror end and a fourth virtual line connecting the axis of rotation and the second mirror end may form a second angle in the direction of the fixed mirror, and the first angle may be wider than the second angle. 
     According to an embodiment of the present disclosure, a LiDAR device comprises: a housing including an outer cover and a window; a laser emitter located in the housing, and configured to output a laser; a detector located in the housing, and configured to detect the laser; a scanner located in the housing, and configured to rotate around an axis of rotation in order to change a flight path of the laser output from the laser emitter; and a fixed mirror located in the housing, and configured to reflect the laser output from the laser emitter and reflected from the scanner when the scanner is in a first position, wherein the scanner may include a reflective surface for changing the flight path of the laser output from the laser emitter, and the reflective surface may be placed at a first predetermined angle with respect to the axis of rotation, and the fixed mirror may be placed at a second predetermined angle with respect to the axis of rotation, and the second predetermined angle may be narrower than the first predetermined angle. 
     According to an embodiment of the present disclosure, a LiDAR device includes: a housing including an outer cover and a window; a laser emitter located in the housing, and configured to output a laser; a detector located in the housing, and configured to detect the laser; a scanner located in the housing, and configured to rotate around an axis of rotation in order to change a flight path of the laser output from the laser emitter; a fixed mirror located in the housing, and configured to reflect the laser output from the laser emitter and reflected from the scanner when the scanner is in a first position, wherein when viewed from the top of the LiDAR device, a distance between the laser emitter and the fixed mirror may be shorter than a distance between the detector and the fixed mirror, and when viewed from the side of the LiDAR device and when the scanner is in the first position, a distance between the laser emitter and a reflective surface may be longer than a distance between the detector and the reflective surface, and when a position of the scanner resulting from rotation by 180 degrees from the first position is referred to as a second position and when the scanner is in the second position, the laser output from the laser emitter may be reflected from the scanner and may pass through a first part of the window, and a vertical location of the fixed mirror may be different from a vertical location of the first part of the window. 
     However, the solving means of the problems of the present disclosure are not limited to the aforementioned solving means and other solving means which are not mentioned will be clearly understood by those skilled in the art from the present specification and the accompanying drawings. 
     According to an embodiment of the present disclosure, a LiDAR device for calculating a distance by using reference measurement can be provided. 
     According to another embodiment of the present disclosure, a LiDAR device for calculating a distance by using reference measurement can be provided. 
     The effects of the present disclosure are not limited to the aforementioned effects and other effects which are not mentioned will be clearly understood by those skilled in the art from the present specification and the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other objectives, features, and other advantages of the present disclosure will be more clearly understood from the following detailed description when taken in conjunction with the accompanying drawings, in which: 
         FIG.  1    is a diagram illustrating a LiDAR device according to an embodiment; 
         FIG.  2    is a diagram illustrating a LiDAR device according to an embodiment; 
         FIG.  3    is a diagram illustrating a LiDAR device according to an embodiment; 
         FIG.  4    is a diagram illustrating a LiDAR device according to an embodiment; 
         FIG.  5    is a diagram illustrating an arrangement relationship between elements included in a LiDAR device, an emission direction and a scan point of a laser according to an embodiment; 
         FIG.  6    is a diagram illustrating an arrangement relationship between elements included in a LiDAR device, an emission direction and a scan point of a laser according to another embodiment; 
         FIG.  7    is a diagram illustrating an arrangement relationship between elements included in a LiDAR device, an emission direction and a scan point of a laser according to yet another embodiment; 
         FIG.  8    is a schematic perspective view of a LiDAR device according to an embodiment; 
         FIG.  9    is a top view of a LiDAR device according to an embodiment; 
         FIGS.  10  and  11    are side views of a LiDAR device according to an embodiment; 
         FIGS.  12  and  13    are front views of a LiDAR device according to an embodiment; 
         FIGS.  14  and  15    are rear views of a LiDAR device according to an embodiment; 
         FIG.  16    is a schematic perspective view of a LiDAR device according to an embodiment; 
         FIG.  17    is a side view of a LiDAR device according to an embodiment; 
         FIG.  18    is a front view of a LiDAR device according to an embodiment; 
         FIG.  19    is a top view of a LiDAR device according to an embodiment; 
         FIGS.  20  and  21    are side views of a LiDAR device according to an embodiment; 
         FIG.  22    is a diagram illustrating a LiDAR device according to an embodiment; 
         FIG.  23    is a diagram illustrating a correlation between a received signal gain and a measurement distance; 
         FIG.  24    is a flowchart illustrating a method of calculating a compensation signal according to an embodiment; 
         FIG.  25    is a diagram illustrating a compensation signal method according to an embodiment; 
         FIGS.  26 A and  26 B  are diagrams illustrating a correlation between a laser output trigger signal and an actual laser output time point; 
         FIGS.  27 A  though  27 C are diagrams illustrating the operation of a distance offset calculator according to an embodiment; 
         FIGS.  28 A through  28 C  are diagrams illustrating the operation of a distance offset calculator according to an embodiment; 
         FIGS.  29 A through  29 C  are diagrams illustrating the operation of a distance offset calculator according to an embodiment; 
         FIGS.  30  and  31    are flowcharts illustrating a method for operating a LiDAR device according to an embodiment; and 
         FIGS.  32 A and  32 B  are diagrams illustrating comparison between measurement results according to an embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Embodiments described in the present specification are for clearly describing the idea of the present disclosure to those skilled in the art to which the present disclosure belongs, so the present disclosure is not limited to the embodiments described in the present specification and the scope of the present disclosure should be construed as including modifications or variations that are within the idea of the present disclosure. 
     As the terms used in the present specification, general terms currently widely used are used considering functions in the present disclosure. However, the terms may vary according to the intentions of those skilled in the art, precedents, or the emergence of new technology. However, unlike this, when a particular term is used defined as having an optional meaning, the meaning of the term will be described. Thus, the terms used in the present specification should be construed based on the actual meanings of the terms and details throughout the present specification rather than simply the names of the terms. 
     The drawings accompanying the present specification are for easily describing the present disclosure, and the shapes shown in the drawings may be exaggerated to help the understanding of the present disclosure, so the present disclosure is not limited by the drawings. 
     In the present specification, if it is decided that a detailed description of known configuration or function related to the present disclosure makes the subject matter of the present disclosure unclear, the detailed description is omitted. 
     According to an embodiment of the present disclosure, a LiDAR (Light Detecting and Ranging) device for measuring distance using a laser comprises: a laser emitter configured to output the laser; a scanner configured to rotate around an axis of rotation, and be located at a reference measurement position and a scan position; a detector configured to detect the laser; and a controller configured to control the laser emitter and the detector, wherein the controller comprises: a laser output controller configured to generate a trigger signal for controlling the laser emitter; and a detector controller configured to process a signal acquired from the detector and control the detector, wherein the detector controller comprises: a correction signal calculator configured to calculate a correction signal to control a voltage applied to the detector; a distance offset calculator configured to calculate a distance offset; and a distance calculator configured to calculate a distance from an object; wherein the correction signal calculator is configured to calculate the correction signal based on a first detecting signal acquired from the detector and outputted from the laser emitter and a reference signal when the scanner locates on the reference measurement position, wherein the distance offset calculator is configured to calculate offset information based on the first detecting signal acquired from the detector and outputted from the laser emitter and reference information when the scanner locates on the reference measurement position, wherein the distance calculator is configured to calculate the distance from the object based on a second detecting signal acquired in the detector and output from the laser emitter and the offset information when the scanner locates on the scan position. 
     Herein, the correction signal calculator may be configured to calculate the correction signal based on a difference between a width of the first detecting signal and a width of the reference signal acquired from the detector. 
     Herein, the correction signal calculator may be configured to calculate the correction signal based on a half of the difference between the width of the first detecting signal and the width of the reference signal acquired from the detector. 
     Herein, the distance offset calculator may be configured to calculate the offset information based on a reference time interval which the reference information comprises and a time point of detection of the first detecting signal acquired from the detector. 
     Herein, the time point of detection of the first detecting signal acquired from the detector may be obtained using a preset threshold and the signal acquired from the detector. 
     Herein, the reference time interval may be a pre-stored time interval based on a reference light path. 
     Herein, the offset information may include at least one of the offset distance and the offset time. 
     Herein, the distance calculator may be configured to calculate the distance from the object based on the offset information and the time point of detection of the second detecting signal and the time point of generation of the trigger signal. 
     Herein, the distance calculator may be configured to calculate the distance from the object by correcting the time interval between the time point of detection of the second detecting signal and the time point of generation of the trigger signal using the offset information. 
     According to an embodiment of the present disclosure, a method for operating LiDAR device for measuring distance using the laser comprises: positioning a scanner in a first reference measurement position; acquiring a first detecting signal for an outputted laser when the scanner is located on the first reference measurement position; acquiring a first compensation signal and first offset information based on the first detecting signal; changing a voltage applied to the detector to a first voltage based on the first compensation signal; positioning the scanner in a first scan position; acquiring a second detecting signal for the outputted laser when the scanner is located on the first scan position; acquiring first distance information based on first offset information and the second detecting signal; positioning the scanner in a second reference measurement position; acquiring a third detecting signal for the outputted laser when the scanner is located on the second reference measurement position; acquiring second offset information and a second compensation signal based on the third detecting signal; changing the voltage applied to the detector to a second voltage based on the second compensation signal; positioning the scanner in the second scan position; acquiring a fourth detecting signal for the outputted laser when the scanner is located on the second scan position; and acquiring the second distance information based on the fourth detecting signal and the second offset information. 
     Herein, the first reference measurement position may be identical to the second reference measurement position. 
     Herein, when the first scan position is identical to the second scan position and the first offset information is different from the second offset information, a time point of detection of the second detecting signal and a time point of detection of the fourth detecting signal may not be same. 
     Herein, the first compensation signal may be acquired based on a width of a pre-stored reference signal and a width of the first detecting signal, and the second compensation signal may be acquired based on the width of the pre-stored reference signal and a width of the third detecting signal. 
     Herein, the first compensation signal may be acquired based on a difference between the width of the pre-stored reference signal and the width of the first detecting signal, and the second compensation signal may be acquired based on a difference between the width of pre-stored reference signal and the width of the third detecting signal. 
     Herein, the first distance information may be acquired based on a difference between a width of a pre-stored reference signal and a width of the first detecting signal, the first offset information and the second detecting signal. 
     Herein, the second distance information may be acquired based on a difference between the width of the pre-stored reference signal and the width of the third detecting signal, the second offset information and the fourth detecting signal. 
     According to an embodiment of the present disclosure, a LiDAR device comprises: a housing including an outer cover and a window; a laser emitter located in the housing, and configured to output a laser; a detector located in the housing, and configured to detect the laser; a scanner located in the housing, and configured to rotate around an axis of rotation in order to change a flight path of the laser output from the laser emitter; and a fixed mirror located in the housing, and configured to reflect the laser output from the laser emitter and reflected from the scanner when the scanner is in a first position, wherein when viewed from the top of the LiDAR device, the window may be formed extending from a first window end to a second window end, and when viewed from the top of the LiDAR device, the fixed mirror may be formed extending from a first mirror end to a second mirror end, and when viewed from the top of the LiDAR device, a first virtual line connecting the axis of rotation and the first window end and a second virtual line connecting the axis of rotation and the second window end may form a first angle in the direction of the window, and when viewed from the top of the LiDAR device, a third virtual line connecting the axis of rotation and the first mirror end and a fourth virtual line connecting the axis of rotation and the second mirror end may form a second angle in the direction of the fixed mirror, and the first angle may be wider than the second angle. 
     Herein, the first angle may be equal to or wider than a 180 degree angle. 
     Herein, the second angle may be equal to or narrower than a 20 degree angle. 
     Herein, when viewed from the top of the LiDAR device, a region surrounded by the first virtual line, the second virtual line, and the window may be referred to as a first region, and when viewed from the top of the LiDAR device, a region surrounded by the third virtual line, the fourth virtual line, and the fixed mirror may be referred to as a second region. In this case, the fixed mirror and the window may be placed such that the first region and the second region do not overlap. 
     Herein, when viewed from the top of the LiDAR device, a size of a region in which the first region and the scanner overlap may be greater than a size of a region in which the second region and the scanner overlap. 
     Herein, when viewed from the top of the LiDAR device, the scanner may include a third region not overlapped by the first region and the second region. 
     Herein, a value obtained by adding the area of the first region, the area of the second region, and the area of the third region may be equal to the area of the scanner when viewed from the top of the LiDAR device. 
     Herein, the first position of the scanner may mean a position in a state in which the scanner is at a particular angle when the scanner rotates around the axis of rotation. 
     According to an embodiment of the present disclosure, a LiDAR device comprises: a housing including an outer cover and a window; a laser emitter located in the housing, and configured to output a laser; a detector located in the housing, and configured to detect the laser; a scanner located in the housing, and configured to rotate around an axis of rotation in order to change a flight path of the laser output from the laser emitter; and a fixed mirror located in the housing, and configured to reflect the laser output from the laser emitter and reflected from the scanner when the scanner is in a first position, wherein the scanner may include a reflective surface for changing the flight path of the laser output from the laser emitter, and the reflective surface may be placed at a first predetermined angle with respect to the axis of rotation, and the fixed mirror may be placed at a second predetermined angle with respect to the axis of rotation, and the second predetermined angle may be narrower than the first predetermined angle. 
     Herein, the first predetermined angle may be a 45 degree angle. 
     Herein, the second predetermined angle may be wider than a 0 degree angle, but may be narrower than a 45 degree angle. 
     Herein, when viewed from one side of the LiDAR device and when the scanner is in the first position, an angle formed by a lower part and an upper part of the scanner and the center of the fixed mirror is a first angle, and the second predetermined angle may be narrower than the half of the first angle. 
     According to an embodiment of the present disclosure, a LiDAR device includes: a housing including an outer cover and a window; a laser emitter located in the housing, and configured to output a laser; a detector located in the housing, and configured to detect the laser; a scanner located in the housing, and configured to rotate around an axis of rotation in order to change a flight path of the laser output from the laser emitter; a fixed mirror located in the housing, and configured to reflect the laser output from the laser emitter and reflected from the scanner when the scanner is in a first position, wherein when viewed from the top of the LiDAR device, a distance between the laser emitter and the fixed mirror may be shorter than a distance between the detector and the fixed mirror, and when viewed from the side of the LiDAR device and when the scanner is in the first position, a distance between the laser emitter and a reflective surface may be longer than a distance between the detector and the reflective surface, and when a position of the scanner resulting from rotation by 180 degrees from the first position is referred to as a second position and when the scanner is in the second position, the laser output from the laser emitter may be reflected from the scanner and may pass through a first part of the window, and a vertical location of the fixed mirror may be different from a vertical location of the first part of the window. 
     Herein, the scanner may include the reflective surface for changing the flight path of the laser output from the laser emitter, and a difference between the vertical location of the fixed mirror and the vertical location of the first part of the window may be smaller than a diameter value of the reflective surface. 
     Herein, the vertical location of the fixed mirror may be defined on the basis of the center of the fixed mirror. 
     Herein, the vertical location of the first part of the window may be defined on the basis of a point at which the first part and the center of the laser passing through the first part meet. 
     1. Summary of a LiDAR Device and Terms 
     A LiDAR device is a device for detecting a distance to an object and the location of the object by using a laser. For example, the LiDAR device may output a laser, and when the output laser is reflected from the object, the LiDAR device receives the reflected laser to measure the distance between the object and the LiDAR device and the location of the object. Herein, the distance and the location of the object may be expressed through a coordinate system. For example, the distance and the location of the object may be expressed in a spherical coordinate system (R, θ, Ø). However, without being limited thereto, the distance and the location of the object may be expressed in a rectangular coordinate system (X, Y, Z) or a cylindrical coordinate system (R, ϵ, Z). 
     In addition, in order to measure the distance to the object, the LiDAR device may use the laser that is output from the LiDAR device and reflected from the object. 
     A LiDAR device according to an embodiment may use the time of flight (TOF) that it takes for a laser to be output and detected so as to measure a distance to an object. For example, the LiDAR device may measure the distance to the object by using the difference between a time value based on the time of output when the laser is output and a time value based on the time of detection when the laser is reflected from the object and detected. 
     In addition to the time of flight (TOF), a LiDAR device according to an embodiment may use a triangulation method, an interferometry method, or phase shift measurement in order to measure a distance to an object, but is not limited thereto. 
     2. Configuration of a LiDAR Device 
     Hereinafter, various embodiments of elements of a LiDAR device will be described in detail. 
       FIG.  1    is a diagram illustrating a LiDAR device according to an embodiment. 
     Referring to  FIG.  1   , a LiDAR device  1000  according to an embodiment may comprise a laser emitter  100 . 
     Herein, a laser emitter  100  according to an embodiment may output a laser. 
     In addition, the laser emitter  100  may comprise one or more laser output elements. For example, the laser emitter  100  may include a single laser output element or a plurality of laser output elements. When the laser emitter  100  comprises a plurality of laser output elements, the plurality of laser output elements may constitute one array. 
     Furthermore, the laser emitter  100  may comprise a laser diode (LD), a solid-state laser, a high power laser, a light-emitting diode (LED), a vertical-cavity surface-emitting laser (VCSEL), or an external cavity diode laser (ECDL), but is not limited thereto. 
     In addition, the laser emitter  100  may output a laser with a predetermined wavelength. For example, the laser emitter  100  may output a laser with a wavelength of 905 nm or a laser with a wavelength of 1550 nm. Furthermore, for example, the laser emitter  100  may output a laser with a wavelength of 940 nm. Furthermore, for example, the laser emitter  100  may output a laser with a plurality of wavelengths ranging from 800 nm to 1000 nm. Furthermore, when the laser emitter  100  includes a plurality of laser output elements, some of the plurality of laser output elements may output lasers with a wavelength of 905 nm, and others may output lasers with a wavelength of 1550 nm. 
     Referring back to  FIG.  1   , a LiDAR device  1000  according to an embodiment may include a scanner  200 . 
     Herein, a scanner  200  according to an embodiment may change the flight path of a laser. For example, the scanner  200  may change the flight path of a laser such that the laser emitted from the laser emitter  100  is toward a scan region. Furthermore, for example, the scanner  200  may change the flight path of the laser such that the laser reflected from an object located in the scan region is toward a detector. 
     In addition, a scanner  200  according to an embodiment may reflect a laser to change the flight path of the laser. For example, the scanner  200  may reflect a laser emitted from the laser emitter  100  to change the flight path of the laser such that the laser is toward a scan region. Furthermore, for example, the scanner  200  may change the flight path of the laser such that the laser reflected from an object located in the scan region is toward a detector. 
     In addition, a scanner  200  according to an embodiment may include various optical means to reflect a laser. For example, the scanner  200  may include a mirror, a resonance scanner, a MEMS mirror, a voice coil motor (VCM), a polygonal mirror, a rotating mirror, or a Galvano mirror, but is not limited thereto. 
     In addition, a scanner  200  according to an embodiment may refract a laser to change the flight path of the laser. For example, the scanner  200  may refract a laser emitted from the laser emitter  100  to change the flight path of the laser such that the laser is toward a scan region. Furthermore, for example, the scanner  200  may change the flight path of the laser such that the laser reflected from an object located in the scan region is toward a detector. 
     In addition, a scanner  200  according to an embodiment may include various optical means to refract a laser. For example, the scanner  200  may include a lens, a prism, a microlens, or a microfluidic lens, but is not limited thereto. 
     In addition, a scanner  200  according to an embodiment may change the phase of a laser to change the flight path of the laser. For example, the scanner  200  may change the phase of a laser emitted from the laser emitter  100  to change the flight path of the laser such that the laser is toward a scan region. Furthermore, for example, the scanner  200  may change the flight path of the laser such that the laser reflected from an object located in the scan region is toward a detector. 
     In addition, a scanner  200  according to an embodiment may include various optical means to change the phase of a laser. For example, the scanner  200  may include an optical phased array (OPA), a meta lens, or a meta surface, but is not limited thereto. 
     In addition, a scanner  200  according to an embodiment may include one or more optical means. Furthermore, for example, the scanner  200  may include a plurality of optical means. 
     Referring back to  FIG.  1   , a LiDAR device  100  according to an embodiment may include a detector  300 . 
     Herein, a detector  300  according to an embodiment may detect a laser. For example, the detector may detect a laser reflected from an object located in a scan region. 
     In addition, a detector  300  according to an embodiment may receive a laser, and may generate an electrical signal on the basis of the received laser. For example, the detector  300  may receive a laser reflected from an object located in a scan region, and may generate an electrical signal on the basis of the received laser. Furthermore, for example, the detector  300  may receive a laser reflected from an object located in a scan region through the scanner  200 , and may generate an electrical signal on the basis of the received laser. 
     In addition, a detector  300  according to an embodiment may detect a laser on the basis of an electrical signal generated. For example, the detector  300  may detect a laser by comparing a predetermined threshold with the magnitude of an electrical signal generated, but is not limited thereto. 
     In addition, a detector  300  according to an embodiment may include various sensor elements. For example, the detector  300  may include a PN photodiode, a photo-transistor, a PIN photodiode, an avalanche photodiode (APD), a single-photon avalanche diode (SPAD), silicon photomultipliers (SiPM), a complementary metal-oxide-semiconductor (CMOS), or a charge coupled device (CCD), but is not limited thereto. 
     In addition, a detector  300  according to an embodiment may include one or more sensor element. For example, the detector  300  may include a single sensor element or a plurality of sensor elements. 
     Referring back to  FIG.  1   , a LiDAR device  1000  according to an embodiment may include a controller  400 . 
     Herein, a controller  400  according to an embodiment may control the operation of the laser emitter  100 , the scanner  200 , or the detector  300 . 
     In addition, a controller  400  according to an embodiment may control the operation of the laser emitter  100 . 
     For example, the controller  400  may control a time point of output of a laser output from the laser emitter  100 . Furthermore, the controller  400  may control the power of a laser output from the laser emitter  100 . Furthermore, the controller  400  may control the pulse width of a laser output from the laser emitter  100 . Furthermore, the controller  400  may control the period (cycle) of a laser output from the laser emitter  100 . Furthermore, when the laser emitter  100  comprises a plurality of laser output elements, the controller  400  may control the laser emitter  100  such that some of the plurality of laser output elements operate in a predetermined sequence. The controller  400  may control the plurality of laser output elements individually, or column by column or row by row. 
     In addition, a controller  400  according to an embodiment may control the operation of the scanner  200 . 
     For example, the controller  400  may control the operating speed of the scanner  200 . Specifically, when the scanner  200  includes a rotating mirror, the controller  400  may control the rotation speed of the rotating mirror. When the scanner  200  includes a MEMS mirror, the controller  400  may control the repetition period of the MEMS mirror. However, no limitation thereto is imposed. 
     In addition, for example, the controller  400  may control the degree of operation of the scanner  200 . Specifically, when the scanner  200  includes a MEMS mirror, the controller  400  may control the angle of operation of the MEMS mirror, but is not limited thereto. 
     In addition, a controller  400  according to an embodiment may control the operation of the detector  300 . 
     For example, the controller  400  may control the sensitivity of the detector  300 . Specifically, the controller  400  may control the sensitivity of the detector  300  by adjusting a predetermined threshold, but is not limited thereto. 
     In addition, for example, the controller  400  may control the operation of the detector  300 . Specifically, the controller  400  may control the on/off operation of the detector  300 . When the detector  300  includes a plurality of sensor elements, the controller  400  may control the operation of the detector  300  such that some of the plurality of sensor elements operate. The controller  400  may control the plurality of sensor individually, column by column, or row by row. 
     In addition, a controller  400  according to an embodiment may determine a distance from the LiDAR device  1000  to an object located in a scan region, on the basis of a laser detected by the detector  300 . 
     For example, the controller  400  may determine a distance to an object located in a scan region, on the basis of a time point of output of a laser from the laser emitter  100  and a time point of detection of the laser by the detector  300 . 
     Specifically, the laser emitter  100  may output a laser, and the controller  400  may acquire a time point of output of the laser from the laser emitter  100 . When the laser output from the laser emitter  100  is reflected from an object located in a scan region, the detector  300  may detect the laser reflected from the object, the controller  400  may acquire a time point of detection of the laser by the detector  300 , and the controller  4000  may use the time point of output of the laser and the time point of detection of the laser to determine a distance to the object located in the scan region. 
       FIG.  2    is a diagram illustrating a LiDAR device according to an embodiment. 
     Referring to  FIG.  2   , a LiDAR device  1100  according to an embodiment may comprise a laser emitter  100 , a scanner  210 , and a detector  300 . 
     Since the laser emitter  100  and the detector  300  have been described with reference to  FIG.  1   , a detailed description of the laser emitter  100  and the detector  300  will be omitted below. 
     A scanner  210  according to an embodiment may be an embodiment of the scanner  200 . For example, the scanner  210  may reflect a laser output from the laser emitter  100  to change the flight path of the laser such that the laser is toward a scan region. 
     In addition, the scanner  210  may include a rotating mirror. 
     In addition, the LiDAR device  1100  may have an emission path that is a light path of a laser output from the laser emitter  1000 . The laser may fly along the emission path toward specific point within the scan region. The laser may reach an object  500  located in the scan region. The laser may be reflected by an object  500  located in the scan region. 
     Specifically, a laser output from the laser emitter  100  may be acquired (received) by the scanner  210 . Furthermore, the laser acquired (received) by the scanner  210  is reflected from the scanner  210  and the flight path of the laser may be changed such that the laser is toward a scan region. Furthermore, the laser reflected from the scanner  210  may reach the object  500 . 
     In addition, the LiDAR device  1100  may have a light-receiving path that is a light path of laser reflected by the object  500 . The reflected laser may fly along the light-receiving path toward the LiDAR device  1100 . The reflected laser along the light-receiving path may be specifically toward the scanner  210  or the detector  300 . 
     Specifically, a laser reflected from the object  500  may be acquired (received) by the scanner  210 . Furthermore, the laser acquired (received) by the scanner  210  may be reflected from the scanner  210  and the flight path of the laser may be changed such that the laser is toward the detector  300 . Furthermore, the laser reflected from the scanner  210  may reach the detector  300 . 
     In addition, a part of the scanner  210  included in the emission path of the LiDAR device  1100  and a part of the scanner  210  included in the light-receiving path may be the same, may be different from each other, or may partially overlap each other, but are not limited thereto. 
     3. Various Embodiments of a LiDAR Device 
       FIGS.  3  and  4    are diagrams illustrating a LiDAR device according to an embodiment. 
     Referring to  FIGS.  3  and  4   , a LiDAR device according to an embodiment may include a laser emitter  120 , a scanner  220 , and a detector  320 . 
     Since the laser emitter  120  and the detector  320  have been described with reference to  FIG.  1   , a detailed description of the laser emitter  120  and the detector  320  will be omitted below. 
     A scanner  220  according to an embodiment may include a reflective surface  221  and a rotary motor  222 . 
     Herein, a reflective surface  221  according to an embodiment may acquire (receive) and reflect a laser. For example, the reflective surface  221  may acquire a laser output from the laser emitter  120  and may reflect the laser toward a scan region. Furthermore, for example, the reflective surface  221  may acquire a laser reflected from an object and may reflect the laser toward the detector  320 . 
     In addition, a reflective surface  221  according to an embodiment may be placed at a predetermined angle with respect to an axis  223  of rotation of the rotary motor  222 . For example, the reflective surface  221  may be placed at a 45 degree angle with respect to the axis  223  of rotation of the rotary motor  222 . 
     In addition, a reflective surface  221  according to an embodiment may change the flight path of a laser output from a laser emitter  120 . For example, as shown in  FIG.  3   , the laser emitter  120  may be placed such that the flight path of the output laser goes in a vertical direction, and the reflective surface  221  may be placed at a 45 degree angle with respect to the axis  223  of rotation. In this case, the flight path may be changed such that the laser output from the laser emitter  120  and traveling in a vertical direction is reflected from the reflective surface  221  and travels in a horizontal direction. 
     In addition, a reflective surface  221  according to an embodiment may be rotated through the rotary motor  222 . Specifically, the reflective surface  221  may rotate around the axis  223  of rotation of the rotary motor  222 . 
     In addition, a reflective surface  221  according to an embodiment may change the flight path of a laser output from the laser emitter  120  into a different direction depending on a rotation angle. For example, when the reflective surface  221  is rotated at an angle as shown in  FIG.  3   , the flight path may be changed such that the laser output from the laser emitter  120  and traveling in a vertical direction is reflected from the reflective surface  221  and travels in a horizontal direction to the left. Conversely, although not shown in  FIG.  3   , when the reflective surface  221  is rotated by 180 degrees around the axis  223  of rotation from the state shown in  FIG.  3   , the flight path may be changed such that the laser output from the laser emitter  120  and traveling in a vertical direction is reflected from the reflective surface  221  and travels in a horizontal direction to the right. 
     Referring back to  FIG.  3   , a laser emitter  120  according to an embodiment may output a laser, and may be placed such that the output laser is incident on the reflective surface  221 . 
     For example, as shown in  FIG.  3   , a laser emitter  120  according to an embodiment may be placed above the reflective surface  221 . 
     In addition, for example, although not shown in  FIG.  3   , the laser emitter  120  may further include a fixed mirror. The fixed mirror may be placed above the reflective surface  221  and the laser emitter  120  may be placed to allow the output laser to be incident on the reflective surface  221 . 
     In addition, the laser emitter  120  may be placed to be spaced apart from the axis  223  of rotation. 
     In addition, although not shown in  FIG.  3   , the laser emitter  120  may be placed to correspond to the axis  223  of rotation. 
     Referring back to  FIG.  3   , a detector  320  according to an embodiment may acquire a laser, and may be placed such that when a laser reflected from an object located in a scan region is reflected from the reflective surface  221 , the detector  320  acquires the laser reflected from the reflective surface  221 . 
     For example, as shown in  FIG.  3   , a detector  320  according to an embodiment may be placed above the reflective surface  221 . 
     In addition, for example, although not shown in  FIG.  3   , the detector  320  may further include a fixed mirror. The fixed mirror may be placed above the reflective surface  221  and the detector  320  may be placed to allow a laser reflected from the reflective surface  221  to be incident on the detector  320 . 
     In addition, the detector  320  may be placed to correspond to the axis  223  of rotation. 
     In addition, although not shown in  FIG.  3   , the detector  320  may be placed to be spaced apart from the axis  223  of rotation. 
     In addition, when the laser emitter  120  is placed to be spaced apart from the axis  223  of rotation, a location on which a laser output from the laser emitter  120  is incident in the reflective surface  221  may be changed as the reflective surface  221  rotates. 
     In addition, when the detector  320  is placed to correspond to the axis  223  of rotation and when a laser acquired by the detector  320  is reflected from the reflective surface  221 , a location in the reflective surface  221  from which the laser is reflected may not be changed even when the reflective surface  221  rotates. 
     In addition, the LiDAR device  1200  may include the laser emitter  120  and the detector  320 , and in the LiDAR device  1200 , the detector  320  may be placed to correspond to the axis  223  of rotation in order to maximize light-receiving efficiency by making the center of a laser acquired by the detector  320  constant, and the laser emitter  120  may be placed to be spaced apart from the axis  223  of rotation so as not to interfere with the laser acquired by the detector  320 . 
     3.1 Arrangement in and a Scan Point of a LiDAR Device According to an Embodiment 
       FIG.  5    is a diagram illustrating an arrangement relationship between elements included in a LiDAR device, an emission direction and a scan point of a laser according to an embodiment. 
     Before describing  FIG.  5   , terms may be defined for convenience of description. Directions, a scan point, and an origin of a LiDAR device may be defined. 
     In addition, in this chapter, directions may be defined using a coordinate system. 
     For example, with respect to a rectangular coordinate system (x, y, z), the +x direction is defined as the forward direction, the −x direction is defined as the backward direction, the +y direction is defined as the right direction, the −y direction is defined as the left direction, the +z direction is defined as the upward direction, and the −z direction is defined as the downward direction. This will be used to describe this chapter. Furthermore, the forward direction may correspond to the center of a plurality of lasers output from a LiDAR device. 
     In addition, in this chapter, a point generated by a laser emitted from a LiDAR device may be defined as a scan point, and the location of the scan point may be expressed using e. Herein, e may mean an angle between the +x axis and a line connecting the origin of the LiDAR device and the scan point, but is not limited thereto. 
     In addition, the origin of the LiDAR device is a virtual point for expressing the location of the scan point, and may be set randomly. For example, the origin of the LiDAR device may be set to correspond to the center of a reflective surface included in a scanner, but is not limited thereto. 
     Referring to  FIG.  5   , a LiDAR device according to an embodiment may comprise a laser emitter  120 , a scanner  220 , and a detector  320 . 
     In addition, the scanner  220  may rotate around an axis of rotation. 
     Herein, the scanner  220  may rotate and may thus be in a first state  2010 , a second state  2020 , and a third state  2030 . 
     In addition, referring to  FIG.  5   , it is shown that a top view  2000  and a front view  2100  in the first state  2010 , the second state  2020 , and the third state  2030 . 
     Herein, referring to the top view  2000  and the front view  2100 , an arrangement relationship between the laser emitter  120 , the scanner  220 , and the detector  320  included in the LiDAR device may be understood. 
     In addition, referring to the top view  2000 , the laser emitter  120  may be placed behind the axis of rotation of the scanner  220 . Furthermore, the detector  320  may be placed to correspond to the axis of rotation of the scanner  220 . 
     In addition, referring to the front view  2100 , the laser emitter  120  may be placed above the scanner  220 . In addition, the detector  320  may be placed above the scanner  220 . 
     Accordingly, the laser emitter  120  may be placed above the scanner  220  and may be placed behind the axis of rotation of the scanner  220 . In addition, the detector  320  may be placed above the scanner  220  and may be placed to correspond to the axis of rotation of the scanner  220 . 
     In addition, referring to the top view  2000  in the first state  2010 , a laser output from the laser emitter  120  may be reflected by the scanner  220  and may be emitted in the left direction. 
     In addition, referring to the front view  2100  in the first state  2010 , a laser output from the laser emitter  120  may be output downward, may be reflected from the scanner  220 , and may be emitted in the left direction. 
     In addition, referring to the top view  2000  and the front view  2100  in the first state  2010 , a laser output from the laser emitter  120  may be incident on a part spaced apart from the center of the scanner  220  when viewed from the top, and may be incident on a part corresponding to the center of the scanner  220  when viewed from the front. 
     In addition, in the first state  2010 , a laser output from the laser emitter  120  may generate a scan point  2210 . Referring to a scan plane  2200 , the laser output from the laser emitter  120  and reflected from the scanner  220  may generate the scan point  2210  at a location near −90 degrees. 
     Specifically, in the first state, the laser output from the laser emitter  120  is incident on a part corresponding to the center of the scanner  220  when viewed from the front, so the laser may generate the scan point  2210  at the center location in the z direction on the scan plane  2200 . 
     In addition, referring to the top view  2000  in the second state  2020 , a laser output from the laser emitter  120  may be reflected from the scanner  220  and may be emitted forward. 
     In addition, referring to the front view  2100  in the second state  2020 , a laser output from the laser emitter  120  may be output downward, may be reflected from the scanner  220 , and may be emitted forward. 
     In addition, referring to the top view  2000  and the front view  2100  in the second state  2020 , a laser output from the laser emitter  120  may be incident on a part spaced apart from the center of the scanner  220  when viewed from the top, and may be incident on a part corresponding to the center of the scanner  220  when viewed from the front. 
     In addition, in the second state  2020 , a laser output from the laser emitter  120  may generate a scan point  2220 . Referring to the scan plane  2200 , the laser output from the laser emitter  120  and reflected from the scanner  220  may generate the scan point  2220  at a location near 0 degrees. 
     Specifically, in the second state  2020 , the laser output from the laser emitter  120  is incident on a part spaced upward from the center of the scanner  220  when viewed from the front, so the laser may generate the scan point  2220  at a location in the +z direction on the scan plane  2200 . 
     In addition, referring to the top view  2000  in the third state  2030 , a laser output from the laser emitter  120  may be reflected from the scanner  220  and may be emitted in the right direction. 
     In addition, referring to the front view  2100  in the third state  2030 , a laser output from the laser emitter  120  may be output downward, may be reflected from the scanner  220 , and may be emitted in the right direction. 
     In addition, referring to the top view  2000  and the front view  2100  in the third state  2030 , a laser output from the laser emitter  120  may be incident on a part spaced apart from the center of the scanner  220  when viewed from the top, and may be incident on a part corresponding to the center of the scanner  220  when viewed from the front. 
     In addition, in the third state  2030 , a laser output from the laser emitter  120  may generate a scan point  2230 . Referring to the scan plane  2200 , the laser output from the laser emitter  120  and reflected from the scanner  220  may generate the scan point  2230  at a location near +90 degrees. 
     Specifically, in the third state  2030 , the laser output from the laser emitter  120  is incident on a part corresponding to the center of the scanner  220  when viewed from the front, so the laser may generate the scan point  2230  at the center location in the z direction on the scan plane  2200 . 
     3.2 Arrangement in and a Scan Point of a LiDAR Device According to Another Embodiment 
       FIG.  6    is a diagram illustrating an arrangement relationship between elements included in a LiDAR device according to another embodiment, and an emission direction and a scan point of a laser. 
     Definitions of terms for describing  FIG.  6    have been described with reference to  FIG.  5   , so a detailed description will be omitted. 
     Referring to  FIG.  6   , a LiDAR device according to an embodiment may include a laser emitter  120 , a scanner  220 , and a detector  320 . 
     In addition, the scanner  220  may rotate around an axis of rotation. 
     Herein, the scanner  220  may rotate and may thus be in a first state  2310 , a second state  2320 , and a third state  2330 . 
     In addition, referring to  FIG.  6   , it is shown that a top view  2300  and a front view  2400  in the first state  2310 , the second state  2320 , and the third state  2330 . 
     Herein, referring to the top view  2300  and the front view  2400 , an arrangement relationship between the laser emitter  120 , the scanner  220 , and the detector  320  included in the LiDAR device may be understood. 
     In addition, referring to the top view  2300 , the laser emitter  120  may be placed in front of the axis of rotation of the scanner  220 . Furthermore, the detector  320  may be placed to correspond to the axis of rotation of the scanner  220 . 
     In addition, referring to the front view  2400 , the laser emitter  120  may be placed above the scanner  220 . In addition, the detector  320  may be placed above the scanner  220 . 
     Accordingly, the laser emitter  120  may be placed above the scanner  220  and may be placed in front of the axis of rotation of the scanner  220 . In addition, the detector  320  may be placed above the scanner  220  and may be placed to correspond to the axis of rotation of the scanner  220 . 
     In addition, referring to the top view  2300  in the first state  2310 , a laser output from the laser emitter  120  may be reflected from the scanner  220  and may be emitted in the left direction. 
     In addition, referring to the front view  2400  in the first state  2310 , a laser output from the laser emitter  120  may be output downward, may be reflected from the scanner  220 , and may be emitted in the left direction. 
     In addition, referring to the top view  2300  and the front view  2400  in the first state  2310 , a laser output from the laser emitter  120  may be incident on a part spaced apart from the center of the scanner  220  when viewed from the top, and may be incident on a part corresponding to the center of the scanner  220  when viewed from the front. 
     In addition, in the first state  2310 , a laser output from the laser emitter  120  may generate a scan point  2510 . Referring to a scan plane  2500 , the laser output from the laser emitter  120  and reflected from the scanner  220  may generate the scan point  2510  at a location near −90 degrees. 
     Specifically, in the first state, the laser output from the laser emitter  120  is incident on a part corresponding to the center of the scanner  220  when viewed from the front, so the laser may generate the scan point  2510  at the center location in the z direction on the scan plane  2500 . 
     In addition, referring to the top view  2300  in the second state  2320 , a laser output from the laser emitter  120  may be reflected from the scanner  220  and may be emitted forward. 
     In addition, referring to the front view  2400  in the second state  2320 , a laser output from the laser emitter  120  may be output downward, may be reflected from the scanner  220 , and may be emitted forward. 
     In addition, referring to the top view  2300  and the front view  2400  in the second state  2320 , a laser output from the laser emitter  120  may be incident on a part spaced apart from the center of the scanner  220  when viewed from the top, and may be incident on a part corresponding to the center of the scanner  220  when viewed from the front. 
     In addition, in the second state  2320 , a laser output from the laser emitter  120  may generate a scan point  2520 . Referring to the scan plane  2500 , the laser output from the laser emitter  120  and reflected from the scanner  220  may generate the scan point  2520  at a location near 0 degrees. 
     Specifically, in the second state  2320 , the laser output from the laser emitter  120  is incident on a part spaced downward from the center of the scanner  220  when viewed from the front, so the laser may generate the scan point  2520  at a location in the −z direction on the scan plane  2500 . 
     In addition, referring to the top view  2300  in the third state  2330 , a laser output from the laser emitter  120  may be reflected from the scanner  220  and may be emitted in the right direction. 
     In addition, referring to the front view  2400  in the third state  2330 , a laser output from the laser emitter  120  may be output downward, may be reflected from the scanner  220 , and may be emitted in the right direction. 
     In addition, referring to the top view  2300  and the front view  2400  in the third state  2330 , a laser output from the laser emitter  120  may be incident on a part spaced apart from the center of the scanner  220  when viewed from the top, and may be incident on a part corresponding to the center of the scanner  220  when viewed from the front. 
     In addition, in the third state  2330 , a laser output from the laser emitter  120  may generate a scan point  2530 . Referring to the scan plane  2500 , the laser output from the laser emitter  120  and reflected from the scanner  220  may generate the scan point  2530  at a location near +90 degrees. 
     Specifically, in the third state  2330 , the laser output from the laser emitter  120  is incident on a part corresponding to the center of the scanner  220  when viewed from the front, so the laser may generate the scan point  2530  at the center location in the z direction on the scan plane  2500 . 
     3.3 Arrangement in and a Scan Point of a LiDAR Device According to Still Another Embodiment 
       FIG.  7    is a diagram illustrating an arrangement relationship between elements included in a LiDAR device according to another embodiment, and an emission direction and a scan point of a laser. 
     Definitions of terms for describing  FIG.  7    have been described with reference to  FIG.  5   , so a detailed description will be omitted. 
     Referring to  FIG.  7   , a LiDAR device according to an embodiment may include a laser emitter  120 , a scanner  220 , and a detector  320 . 
     In addition, the scanner  220  may rotate around an axis of rotation. 
     Herein, the scanner  220  may rotate and may thus be in a first state  2610 , a second state  2620 , and a third state  2630 . 
     In addition, referring to  FIG.  7   , it is shown that a top view  2600  and a front view  2700  in the first state  2610 , the second state  2620 , and the third state  2630 . 
     Herein, referring to the top view  2600  and the front view  2700 , an arrangement relationship between the laser emitter  120 , the scanner  220 , and the detector  320  included in the LiDAR device may be understood. 
     In addition, referring to the top view  2600 , the laser emitter  120  may be placed to the right of the axis of rotation of the scanner  220 . Furthermore, the detector  320  may be placed to correspond to the axis of rotation of the scanner  220 . 
     In addition, referring to the front view  2600 , the laser emitter  120  may be placed above the scanner  220 . In addition, the detector  320  may be placed above the scanner  220 . 
     Accordingly, the laser emitter  120  may be placed above the scanner  220  and may be placed to the right of the axis of rotation of the scanner  220 . In addition, the detector  320  may be placed above the scanner  220  and may be placed to correspond to the axis of rotation of the scanner  220 . 
     In addition, referring to the top view  2600  in the first state  2610 , a laser output from the laser emitter  120  may be reflected from the scanner  220  and may be emitted in the left direction. 
     In addition, referring to the front view  2700  in the first state  2610 , a laser output from the laser emitter  120  may be output downward, may be reflected from the scanner  220 , and may be emitted in the left direction. 
     In addition, referring to the top view  2600  and the front view  2700  in the first state  2610 , a laser output from the laser emitter  120  may be incident on a part spaced apart from the center of the scanner  220  when viewed from the top, and may be incident on a part spaced upward from the center of the scanner  220  when viewed from the front. 
     In addition, in the first state  2610 , a laser output from the laser emitter  120  may generate a scan point  2810 . Referring to a scan plane  2800 , the laser output from the laser emitter  120  and reflected from the scanner  220  may generate the scan point  2810  at a location near −90 degrees. 
     Specifically, in the first state, the laser output from the laser emitter  120  is incident on a part spaced upward from the scanner  220  when viewed from the front, so the laser may generate the scan point  2810  at a location spaced in the +z direction on the scan plane  2800 . 
     In addition, referring to the top view  2600  in the second state  2620 , a laser output from the laser emitter  120  may be reflected from the scanner  220  and may be emitted forward. 
     In addition, referring to the front view  2600  in the second state  2620 , a laser output from the laser emitter  120  may be output downward, may be reflected from the scanner  220 , and may be emitted forward. 
     In addition, referring to the top view  2600  and the front view  2700  in the second state  2620 , a laser output from the laser emitter  120  may be incident on a part spaced apart from the center of the scanner  220  when viewed from the top, and may be incident on a part spaced rightward from the center of the scanner  220  when viewed from the front. 
     In addition, in the second state  2620 , a laser output from the laser emitter  120  may generate a scan point  2820 . Referring to the scan plane  2800 , the laser output from the laser emitter  120  and reflected from the scanner  220  may generate the scan point  2820  at a location near 0 degrees. 
     Specifically, in the second state, the laser output from the laser emitter  120  is incident on a part corresponding to the up-down center of the scanner  220  when viewed from the front, so the laser may generate the scan point  2820  at a location corresponding to the center in the z direction on the scan plane  2800 . 
     In addition, referring to the top view  2600  in the third state  2630 , a laser output from the laser emitter  120  may be reflected from the scanner  220  and may be emitted in the right direction. 
     In addition, referring to the front view  2600  in the third state  2630 , a laser output from the laser emitter  120  may be output downward, may be reflected from the scanner  220 , and may be emitted in the right direction. 
     In addition, referring to the top view  2600  and the front view  2700  in the third state  2630 , a laser output from the laser emitter  120  may be incident on a part spaced apart from the center of the scanner  220  when viewed from the top, and may be incident on a part spaced downward from the center of the scanner  220  when viewed from the front. 
     In addition, in the third state  2630 , a laser output from the laser emitter  120  may generate a scan point  2830 . Referring to the scan plane  2800 , the laser output from the laser emitter  120  and reflected from the scanner  220  may generate the scan point  2830  at a location near +90 degrees. 
     Specifically, in the third state, the laser output from the laser emitter  120  is incident on a part spaced downward from the scanner  220  when viewed from the front, so the laser may generate the scan point  2830  at a location spaced in the −z direction on the scan plane  2800 . 
     As described above with reference to  FIGS.  5  to  7   , when the laser emitter  120  is placed spaced apart from the axis of rotation of the scanner  220 , the generation location of the scan point varies in the z direction according to the placement of the laser emitter  120  and the rotation of the scanner  220 . Therefore, it is necessary to consider effective placement of the laser emitter  120  considering the purpose of use and the effects of the LiDAR device. 
     For example, in order to minimize the distance between the scan points in the z direction on the scan plane, it is preferable that the laser emitter is placed ahead of or behind the axis of rotation of the scanner when viewed from the top. 
     In addition, for example, in order to make up for the slope of the ground, it is preferable that the laser emitter is placed to the left or right of the axis of rotation of the scanner when viewed from the top. 
     4. Various Embodiments of a LiDAR Device 
       FIG.  8    is a perspective view of a LiDAR device according to an embodiment. 
     Referring to  FIG.  8   , a LiDAR device  3000  according to an embodiment may include a laser emitter  3100 , a scanner  3200 , a detector  3300 , an angle measurement part  3400 , and a fixed mirror  3500 . 
     Furthermore, the laser emitter  3100  may include a laser output device  3110  and an emission lens  3120 , but is not limited thereto. 
     Furthermore, the scanner  3200  may include a reflective surface  3210  and a rotary motor  3220 , but is not limited thereto. 
     Furthermore, the detector  3300  may include a detection sensor  3310  and a light-receiving lens  3320 , but is not limited thereto. 
     In addition, the above-described details may be applied to the laser emitter  3100 , the scanner  3200 , and the detector  3300 , so a redundant description will be omitted. 
     Furthermore, the angle measurement part  3400  may measure a rotation angle of the scanner  3200 . 
     Furthermore, the angle measurement part  3400  may be provided in the form of a photo coupler, a photo reflector, an encoder, etc., but is not limited thereto. 
     Furthermore, the fixed mirror  3500  may be a member for measuring at least one reference for distance measurement. 
     For example, at least one reference information for distance measurement may be acquired using time and intensity information of a laser output from the laser emitter  3100  and reflected from the fixed mirror  3500  and then acquired by the detector  3300 , but no limitation thereto is imposed. 
     For a more specific example, a first light path of a laser output from the laser emitter  3100  and acquired (or received) by the fixed mirror  3500  and a second light path of the laser reflected by the fixed mirror  3500  and acquired by the detector may be set as a reference light path. Herein, a reference measurement distance may be acquired from a time interval between a time point of generation of a trigger signal for outputting the laser from the laser emitter  3100  and a time point of detection of the laser by the detector  3300 . A reference correction value may be acquired on the basis of a difference between the length of the reference light path and the reference measurement distance. However, no limitation thereto is imposed. 
     In addition, for a more specific example, a table for a value of [reflectance/laser power] may be acquired on the basis of intensity information of a laser output from the laser emitter  3100  and reflected from the fixed mirror  3500  and then acquired by the detector  3300 , but is not limited thereto. 
       FIG.  9    is a top view of a LiDAR device according to an embodiment. 
     Referring to  FIG.  9   , a LiDAR device  3000  according to an embodiment may include a laser emitter  3100 , a scanner  3200 , a detector  3300 , an angle measurement part  3400 , and a fixed mirror  3500 . 
     Herein, the above-described details may be applied to each element of the LiDAR device  3000 , so a redundant description will be omitted. 
     Referring to  FIG.  9   , when viewed from the top of the LiDAR device  3000 , the scanner  3200  may be provided in the shape of a circular plate. 
     In addition, when viewed from the top of the LiDAR device  3000 , the laser emitter  3100  and the detector  3300  may be placed to be located in a region of the scanner  3200 . 
     In addition, when viewed from the top of the LiDAR device  3000 , the laser emitter  3100  may be placed to be closer to the fixed mirror  3500  than the detector  3300 . 
     In addition, when viewed from the top of the LiDAR device  3000 , the fixed mirror  3500  may be located behind the scanner  3200 . 
     In addition, when viewed from the top of the LiDAR device  3000 , the fixed mirror  3500  may be placed to have a thickness. This may mean that the fixed mirror  3500  is placed at a predetermined angle with respect to an axis of rotation of a rotary motor  3220 , but is not limited thereto. 
     In addition, when viewed from the top of the LiDAR device  3000 , the angle measurement part  3400  may be placed to be at least partially overlapped by the fixed mirror  3500 . 
       FIGS.  10  and  11    are side views of a LiDAR device according to an embodiment. 
     Referring to  FIGS.  10  and  11   , a LiDAR device  3000  according to an embodiment may include a laser emitter  3100 , a scanner  3200 , a detector  3300 , an angle measurement part  3400 , and a fixed mirror  3500 . 
     Herein, the above-described details may be applied to each element of the LiDAR device  3000 , so a redundant description will be omitted. 
     Referring to  FIG.  10   , the scanner  3200  may have a first position. Herein, the first position may mean a position of the scanner  3200  at a time point during the rotation operation of the scanner  3200 . Referring to  FIG.  11   , the scanner  3200  may have a second position. Herein, the second position may mean a position of the scanner  3200  at a time point during the rotation operation of the scanner  3200 . The second position may mean a position resulting from rotation by 180 degrees from the first position, but is not limited thereto. 
     Referring to  FIG.  10   , when the scanner  3200  is in the first position, the shortest vertical distance from the laser emitter  3100  to a reflective surface  3210  may be shorter than the shortest vertical distance from the detector  3300  to the reflective surface  3210 . 
     In addition, when viewed from one side of the LiDAR device  3000  and when the scanner  3200  is in the first position, a laser output from the laser emitter  3100  may be reflected from an upper region of the reflective surface  3210  and may be emitted forward, and the laser acquired from the front by the reflective surface  3210  may be reflected from a lower region of the reflective surface  3210  and may be acquired by the detector  3300 . 
     In addition, referring to  FIG.  11   , when the scanner  3200  is in the second position, the shortest vertical distance from the laser emitter  3100  to the reflective surface  3210  may be longer than the shortest vertical distance from the detector  3300  to the reflective surface  3210 . 
     In addition, when viewed from one side of the LiDAR device  3000  and when the scanner  3200  is in the second position, a laser output from the laser emitter  3100  may be reflected from the lower region of the reflective surface  3210  and may be emitted to the fixed mirror  3500 , and the laser reflected from the fixed mirror  3500  and acquired by the reflective surface  3210  may be reflected from the upper region of the reflective surface  3210  and may be acquired by the detector  3300 . 
     In addition, when viewed from one side of the LiDAR device  3000 , the laser emitter  3100  may be placed on one side from an axis of rotation of a rotary motor  3220  included in the scanner  3200 , and the detector  3300  may be placed on another side from the axis of rotation of the rotary motor  3221  included in the scanner  3200 . 
     In addition, when viewed from one side of the LiDAR device  3000 , the fixed mirror  3500  may be placed to be closer to the laser emitter  3100  than to the detector  3300 . 
     In addition, when viewed from one side of the LiDAR device  3000 , the fixed mirror  3500  may be placed below the laser emitter  3100  and the detector  3300 . 
     In addition, when viewed from one side of the LiDAR device  3000 , the fixed mirror  3500  may be located in the vertical direction at a region corresponding to a part of the reflective surface  3210  included in the scanner  3200 . This may mean that a vertical location value of the fixed mirror  3500  and a vertical location value of the reflective surface  3210  overlap at least partially, but is not limited thereto. 
     In addition, when viewed from one side of the LiDAR device  3000 , the reflective surface  3210  included in the scanner  3200  may be placed at a first predetermined angle with respect to the axis of rotation of the rotary motor  3221 , and the fixed mirror  3500  may be placed at a second predetermined angle with respect to the axis of rotation of the rotary motor  3221 . 
     Herein, the first predetermined angle and the second predetermined angle may be different from each other. 
     Furthermore, herein, the second predetermined angle may be smaller than the first predetermined angle. 
     In addition, when viewed from one side of the LiDAR device  3000 , the angle measurement part  3400  may be placed below the fixed mirror  3500 . 
     In addition, when viewed from one side of the LiDAR device  3000 , the angle measurement part  3400  may be located in the vertical direction at a region not corresponding to a part of the reflective surface  3210  included in the scanner  3200 . This may mean that the vertical location value of the angle measurement part  3400  and the vertical location value of the reflective surface  3210  do not overlap at least partially, but is not limited thereto. 
       FIGS.  12  and  13    are front views of a LiDAR device according to an embodiment. 
     Referring to  FIGS.  12  and  13   , a LiDAR device  3000  according to an embodiment may include a laser emitter  3100 , a scanner  3200 , a detector  3300 , an angle measurement part  3400 , and a fixed mirror  3500 . 
     Herein, the above-described details may be applied to each element of the LiDAR device  3000 , so a redundant description will be omitted. 
     Referring to  FIG.  12   , the scanner  3200  may have a first position. Herein, the first position may mean a position of the scanner  3200  at a time point during the rotation operation of the scanner  3200 . Referring to  FIG.  13   , the scanner  3200  may have a second position. Herein, the second position may mean a position of the scanner  3200  at a time point during the rotation operation of the scanner  3200 . The second position may mean a position resulting from rotation by 180 degrees from the first position, but is not limited thereto. 
     Referring to  FIG.  12   , when viewed from the front of the LiDAR device  3000  and when the scanner  3200  is in the first position, a reflective surface  3210  included in the scanner  3200  may look like an ellipse shape. 
     In addition, referring to  FIG.  13   , when viewed from the front of the LiDAR device  3000  and when the scanner  3200  is in the second position, the reflective surface  3210  included in the scanner  3200  may be invisible. 
     In addition, when viewed from the front of the LiDAR device  3000 , the laser emitter  3100  and the detector  3300  may be placed to overlap at least partially. 
     In addition, when viewed from the front of the LiDAR device  3000 , the laser emitter  3100  and the detector  3300  may be placed to overlap with an axis  3221  of rotation of a rotary motor  3220  included in the scanner  3200 . 
       FIGS.  14  and  15    are rear views of a LiDAR device according to an embodiment. 
     Referring to  FIGS.  14  and  15   , a LiDAR device  3000  according to an embodiment may include a laser emitter  3100 , a scanner  3200 , a detector  3300 , an angle measurement part  3400 , and a fixed mirror  3500 . 
     Herein, the above-described details may be applied to each element of the LiDAR device  3000 , so a redundant description will be omitted. 
     Referring to  FIG.  14   , the scanner  3200  may have a first position. Herein, the first position may mean a position of the scanner  3200  at a time point during the rotation operation of the scanner  3200 . Referring to  FIG.  15   , the scanner  3200  may have a second position. Herein, the second position may mean a position of the scanner  3200  at a time point during the rotation operation of the scanner  3200 . The second position may mean a position resulting from rotation by 180 degrees from the first position, but is not limited thereto. 
     Referring to  FIG.  14   , when viewed from the rear of the LiDAR device  3000  and when the scanner  3200  is in the first position, a reflective surface  3210  included in the scanner  3200  may be invisible. 
     In addition, referring to  FIG.  15   , when viewed from the rear of the LiDAR device  3000  and when the scanner  3200  is in the second position, the reflective surface  3210  included in the scanner  3200  may look like an ellipse shape. 
     In addition, when viewed from the rear of the LiDAR device  3000 , the laser emitter  3100 , the detector  3300 , the angle measurement part  3400 , and the fixed mirror  3500  may be placed to overlap with an axis  3221  of rotation of a rotary motor  3220  included in the scanner  3200 . 
     In addition, when viewed from the rear of the LiDAR device  3000 , the fixed mirror  3500  may be placed below the laser emitter  3100  and the detector  3300 . 
     In addition, when viewed from the rear of the LiDAR device  3000 , the fixed mirror  3500  may be located at a region corresponding to a part of the reflective surface  3210  included in the scanner  3200 . This may mean that a vertical location value of the fixed mirror  3500  and a vertical location value of the reflective surface  3210  overlap at least partially, but is not limited thereto. 
     In addition, when viewed from the rear of the LiDAR device  3000 , the fixed mirror  3500  may be located to correspond to a lower region of the reflective surface  3210  included in the scanner  3200 . 
     In addition, when viewed from the rear of the LiDAR device  3000 , the angle measurement part  3400  may be placed below the fixed mirror  3500 . 
     In addition, when viewed from the rear of the LiDAR device  3000 , the angle measurement part  3400  may be located not to correspond to the reflective surface  3210  included in the scanner  3200 . 
       FIG.  16    is a perspective view of a LiDAR device according to an embodiment. 
     Referring to  FIG.  16   , a LiDAR device  3000  according to an embodiment may include a laser emitter  3100 , a scanner  3200 , a detector  3300 , an angle measurement part  3400 , a fixed mirror  3500 , and a housing  3600 . 
     Herein, the above-described details may be applied to the laser emitter  3100 , the scanner  3200 , the detector  3300 , the angle measurement part  3400 , and the fixed mirror  3500 , so a redundant description will be omitted. 
     Referring to  FIG.  16   , the laser emitter  3100 , the scanner  3200 , the detector  3300 , the angle measurement part  3400 , and the fixed mirror  3500  may be included within the housing. 
     Furthermore, the housing  3600  may comprise an outer cover  3610  and a window  3620 . 
     In addition, the inside of the housing  3600  may be sealed by the outer cover  3610  and the window  3620 . 
     Herein, the outer cover  3610  may protect the elements of the LiDAR device  3000  located in the housing from an external environment. 
     Furthermore, the outer cover  3610  may optically shield to prevent the elements of the LiDAR device  3000  located in the housing from being disturbed by external light. 
     In addition, the window  3620  may protect the elements of the LiDAR device  3000  located in the housing from the external environment. 
     Furthermore, the window  3620  may have an optical window so that a laser output from the laser emitter  3100  can be emitted to the outside and the laser reflected from an object is acquired by the detector  3300  through the optical window. For example, a laser output from the laser emitter  3100  and reflected from the scanner  3200  can pass through the window  3620 , and the laser reflected from an object can pass through the window  3620  so that the laser reflected from the object is reflected from the scanner  3200  and is acquired by the detector  3300 . 
     Furthermore, the window  3620  may be placed to constitute a partial region of the housing  3600 . 
       FIG.  17    is a side view of a LiDAR device according to an embodiment. 
     Referring to  FIG.  17   , a LiDAR device  3000  according to an embodiment may include a laser emitter  3100 , a scanner  3200 , a detector  3300 , an angle measurement part  3400 , a fixed mirror  3500 , and a housing  3600 . 
     Herein, the above-described details may be applied to each element of the LiDAR device  3000 , so a redundant description will be omitted. 
     Referring to  FIG.  17   , when viewed from one side of the LiDAR device  3000 , a window  3620  included in the housing  3600  may be located at a region of the housing  3600 . 
     In addition, when viewed from one side of the LiDAR device  3000 , the window  3620  included in the housing  3600  may be located such that the window  3620  and at least a part of a reflective surface  3210  included in the scanner  3200  overlap. This may mean that when viewed from one side of the LiDAR device  3000 , at least a part of the reflective surface  3210  is optically visible through the window  3620 , wherein being optically visible may mean that observation is achieved using a sensor for acquiring light of at least one wavelength band. However, no limitation thereto is imposed, and a concept that the window  3620  and at least a part of the reflective surface  3210  are located at physically overlapping regions may be included. 
     In addition, when viewed from one side of the LiDAR device  3000 , the window  3620  included in the housing  4600  may be located such that the window  3620  and the laser emitter  3100  do not overlap. This may mean that when viewed from one side of the LiDAR device  3000 , the laser emitter  3100  is optically invisible through the window  3620 , wherein being optically invisible may mean that observation is not achieved using a sensor for acquiring light of at least one wavelength band. However, no limitation thereto is imposed, and a concept that the window  3620  and the laser emitter  3100  are located at regions that do not physically overlap may be included. 
     In addition, when viewed from one side of the LiDAR device  3000 , the window  3620  included in the housing  3600  may be located such that the window  3620  and the detector  3300  do not overlap. 
     In addition, when viewed from one side of the LiDAR device  3000 , the window  3620  included in the housing  3600  may be located such that the window  3620  and a rotary motor  3220  included in the scanner  3200  do not overlap. 
     In addition, when viewed from one side of the LiDAR device  3000 , the window  3620  included in the housing  3600  may be located such that the window  3620  and the angle measurement part  3400  do not overlap. 
     In addition, when viewed from one side of the LiDAR device  3000 , the window  3620  included in the housing  3600  may be located such that the window  3620  and the fixed mirror  3500  do not overlap. 
       FIG.  18    is a front view of a LiDAR device according to an embodiment. 
     Referring to  FIG.  18   , a LiDAR device  3000  according to an embodiment may include a laser emitter  3100 , a scanner  3200 , a detector  3300 , an angle measurement part  3400 , a fixed mirror  3500 , and a housing  3600 . 
     Herein, the above-described details may be applied to each element of the LiDAR device  3000 , so a redundant description will be omitted. 
     Referring to  FIG.  18   , when viewed from the front of the LiDAR device  3000 , a window  3620  included in the housing  3600  may be located at a region of the housing  3600 . 
     In addition, when viewed from the front of the LiDAR device  3000 , the window  3620  included in the housing  3600  may be located such that the window  3620  and at least a part of a reflective surface  3210  included in the scanner  3200  overlap. This may mean that when viewed from the front of the LiDAR device  3000 , at least a part of the reflective surface  3210  is optically visible through the window  3620 , wherein being optically visible may mean that observation is achieved using a sensor for acquiring light of at least one wavelength band. However, no limitation thereto is imposed, and a concept that the window  3620  and at least a part of the reflective surface  3210  are located at physically overlapping regions may be included. 
     For example, in  FIG.  18   , an upper region and a middle region of the reflective surface  3210  and the window  3620  may overlap, but are not limited thereto. 
     In addition, when viewed from the front of the LiDAR device  3000 , the area of the region of the window  3620  included in the housing  3600  may be larger than the area of the reflective surface  3210  included in the scanner  3200 . 
     In addition, when viewed from the front of the LiDAR device  3000 , the window  3620  included in the housing  3600  may be located such that the window  3620  and at least a part of the reflective surface  3210  included in the scanner  3200  do not overlap. This may mean that when viewed from the front of the LiDAR device  3000 , at least a part of the reflective surface  3210  is optically invisible through the window  3620 . For example, in  FIG.  18   , a lower region of the reflective surface  3210  and the window  3620  may not over. 
     In addition, when viewed from the front of the LiDAR device  3000 , the window  3620  included in the housing  4600  may be located such that the window  3620  and the laser emitter  3100  do not overlap. This may mean that when viewed from one side of the LiDAR device  3000 , the laser emitter  3100  is optically invisible through the window  3620 , wherein being optically invisible may mean that observation is not achieved using a sensor for acquiring light of at least one wavelength band. However, no limitation thereto is imposed, and a concept that the window  3620  and the laser emitter  3100  are located at regions that do not physically overlap may be included. 
     In addition, when viewed from the front of the LiDAR device  3000 , the window  3620  included in the housing  3600  may be located such that the window  3620  and the detector  3300  do not overlap. 
     In addition, when viewed from the front of the LiDAR device  3000 , the window  3620  included in the housing  3600  may be located such that the window  3620  and a rotary motor  3220  included in the scanner  3200  do not overlap. 
     In addition, when viewed from the front of the LiDAR device  3000 , the window  3620  included in the housing  3600  may be located such that the window  3620  and the angle measurement part  3400  do not overlap. 
     In addition, when viewed from the front of the LiDAR device  3000 , the window  3620  included in the housing  3600  may be located such that the window  3620  and the fixed mirror  3500  do not overlap. 
       FIG.  19    is a top view of a LiDAR device according to an embodiment. 
     Referring to  FIG.  19   , a LiDAR device  3000  according to an embodiment may include a laser emitter  3100 , a scanner  3200 , a detector  3300 , an angle measurement part  3400 , a fixed mirror  3500 , and a window  3620 . 
     Herein, the above-described details may be applied to each element of the LiDAR device  3000 , so a redundant description will be omitted. 
     Referring to  FIG.  19   , when viewed from the top of the LiDAR device  3000 , the window  3620  may have a first window end  3621  and a second window end  3622 . 
     Furthermore, when viewed from the top of the LiDAR device  3000 , the window  3620  may be formed extending from the first window end  3621  to the second window end  3622 . 
     Furthermore, when viewed from the top of the LiDAR device  3000 , the window  3620  may be formed in the shape of an arc extending from the first window end  3621  to the second window end  3622 . 
     In addition, when viewed from the top of the LiDAR device  3000 , the fixed mirror  3500  may have a first mirror end  3501  and a second mirror end  3502 . 
     Furthermore, when viewed from the top of the LiDAR device  3000 , the fixed mirror  3500  may be formed extending from the first mirror end  3501  to the second mirror end  3502 . 
     Furthermore, when viewed from the top of the LiDAR device  3000 , the fixed mirror  3500  may be formed in the shape of a quadrangle extending from the first mirror end  3501  to the second mirror end  3502 . 
     In addition, when viewed from the top of the LiDAR device  3000 , a first virtual line and a second virtual line may form a first angle a 1  therebetween, wherein the first virtual line may be a line connecting the center of a reflective surface  3210  included in the scanner  3200  to the first window end  3621 , and the second virtual line may be a line connecting the center of the reflective surface  3210  to the second window end  3622 . 
     In addition, when viewed from the top of the LiDAR device  3000 , a third virtual line and a fourth virtual line may form a second angle a 2  therebetween, wherein the third virtual line may be a line connecting the center of the reflective surface  3210  to the first mirror end  3501 , and the fourth virtual line may be a line connecting the center of the reflective surface  3210  to the second mirror end  3502 . 
     Herein, the first angle a 1  and the second angle a 2  may be different from each other. 
     Furthermore, the first angle a 1  may be wider than the second angle a 2 . 
     Furthermore, the first angle a 1  may be equal to or wider than a 180 degree angle. 
     Furthermore, the second angle a 2  may be equal to or narrower than a 20 degree angle. 
     In addition, when viewed from the top of the LiDAR device  3000 , a first region and the detector  3300  may overlap at least partially, wherein the first region is a region surrounded by the first virtual line, the second virtual line, and the window  3620 . 
     This may mean that when viewed from the top of the LiDAR device  3000 , the detector  3300  is located such that the detector  3300  and the first region overlap at least partially. 
     In addition, when viewed from the top of the LiDAR device  3000 , a second region and the laser emitter  3100  may overlap at least partially, wherein the second region is a region surrounded by the third virtual line, the fourth virtual line, and the fixed mirror  3500 . 
     This may mean that when viewed from the top of the LiDAR device  3000 , the laser emitter  3100  is located such that the laser emitter  3100  and the second region overlap at least partially. 
     In addition, when viewed from the top of the LiDAR device  3000 , the area of the first region may be larger than the area of the second region. 
     In addition, when viewed from the top of the LiDAR device  3000 , the reflective surface  3210  and the first region may overlap at least partially and the reflective surface  3210  and the second region may overlap at least partially. 
     Herein, when viewed from the top of the LiDAR device  3000 , the area of the part of the reflective surface  3210  overlapped by the first region may be larger than the area of the part of the reflective surface  3210  overlapped by the second region. 
     In addition, when viewed from the top of the LiDAR device  3000 , the first region and the second region may not overlap each other. 
     In addition, when viewed from the top of the LiDAR device  3000 , the window  3620  may be located such that the window  3620  and the second region do not overlap. 
     In addition, when viewed from the top of the LiDAR device  3000 , the fixed mirror  3500  may be located such that the fixed mirror  3500  and the first region do not overlap. 
       FIGS.  20  and  21    are side views of a LiDAR device according to an embodiment. 
     Referring to  FIGS.  20  and  21   , a LiDAR device  3000  according to an embodiment may include a laser emitter  3100 , a scanner  3200 , a detector  3300 , an angle measurement part  3400 , a fixed mirror  3500 , and a housing  3600 . 
     Herein, the above-described details may be applied to each element of the LiDAR device  3000 , so a redundant description will be omitted. 
     Referring to  FIG.  20   , the scanner  3200  may have a first position. Herein, the first position may mean a position of the scanner  3200  at a time point during the rotation operation of the scanner  3200 . Referring to  FIG.  21   , the scanner  3200  may have a second position. Herein, the second position may mean a position of the scanner  3200  at a time point during the rotation operation of the scanner  3200 . The second position may mean a position resulting from rotation by 180 degrees from the first position, but is not limited thereto. 
     Herein, the first position may be a position included in a scan position, and the second position may be a position included in a reference measurement position. 
     Furthermore, the scan position may mean a position of the scanner in which a laser output from the laser emitter is emitted to the outside of the LiDAR device. The reference measurement position may mean a position of the scanner in which a laser output from the laser emitter is received by the detector along a preset reference light path. However, no limitation thereto is imposed. 
     Referring to  FIG.  20   , when viewed from one side of the LiDAR device  3000  and when the scanner  3200  is in the first position, a laser output from the laser emitter  3100  is reflected from a reflective surface  3210 , and a first part  3621  of the window  3620  included in the housing  3600  may be located on the path of the laser reflected from the reflective surface  3210 . 
     In addition, referring to  FIG.  21   , when viewed from one side of the LiDAR device  3000  and when the scanner  3200  is in the second position, a laser output from the laser emitter  3100  is reflected from the reflective surface  3210 , and the fixed mirror  3500  may be located on the path of the laser reflected from the reflective surface  3210 . 
     Herein, when viewed from one side of the LiDAR device  3000 , the first part  3621  of the window  3620  and the fixed mirror  3500  may differ in vertical location. That is, a height of the first part  3621  may be different from a height of the fixed mirror  3500 . 
     For example, the vertical location of the first part  3621  of the window  3620  may correspond to an upper region of the reflective surface  3210 , and the vertical location of the fixed mirror  3500  may correspond to a lower region of the reflective surface  3210 , but no limitation thereto is imposed. 
     In addition, when viewed from one side of the LiDAR device  3000 , the reflective surface  3210  may be placed at a first predetermined angle with respect to an axis  3221  of rotation of a rotary motor  3220  included in the scanner  3200 , and the fixed mirror  3500  may be placed at a second predetermined angle with respect to the axis  3221  of rotation, and the window  3620  may be placed at a third predetermined angle with respect to the axis  3221  of rotation. 
     Herein, the first to the third predetermined angles may be different from each other. 
     Furthermore, the first predetermined angle may be larger than the second predetermined angle, and the second predetermined angle may be larger than the third predetermined angle. 
       FIG.  22    is a diagram illustrating a LiDAR device according to an embodiment. 
     Referring to  FIG.  22   , a LiDAR device ( 4000 ) according to an embodiment may least one of the following elements: a laser emitter  4100 , a scanner  4200 , a detector  4300 , and a controller  4400 . 
     Herein, the above-described details may be applied to the laser emitter  4100 , the scanner  4200 , the detector  4300 , and the controller  4400 , so a redundant description will be omitted. 
     Furthermore, the controller  4400  may include at least one of the following elements: a laser output controller  4410 , a scan controller  4420 , and a detector controller  4430 . 
     Herein, the laser output controller  4410  may control various operations of the laser emitter  4100 . 
     For example, the laser output controller  4410  may generate a trigger signal for laser output, but is not limited thereto. 
     In addition, for example, the laser output controller  4410  may control the amount of voltage for laser output, but is not limited thereto. 
     In addition, for example, the laser output controller  4410  may control the amount of current for laser output, but is not limited thereto. 
     In addition, for example, the laser output controller  4410  may control the pulse width of a laser output, but is not limited thereto. 
     In addition, for example, the laser output controller  4410  may control the power of a laser output, but is not limited thereto. 
     In addition to the above-described details, the laser output controller  4410  may control various operations of the laser emitter  4100 . 
     Herein, the controlling of the various operations of the laser emitter  4100  by the laser output controller  4410  may mean generating at least one signal for controlling the various operations of the laser emitter  4100 , but is not limited thereto. 
     In addition, the scan controller  4420  may control various operations of the scanner  4200 . 
     For example, the scan controller  4420  may control the rotation speed of the scanner  4200 , but is not limited thereto. 
     In addition, for example, the scan controller  4420  may monitor the rotation angle of the scanner  4200 , but is not limited thereto. 
     In addition, for example, the scan controller  4420  may control the rotation direction of the scanner  4200 , but is not limited thereto. 
     In addition to the above-described details, the scan controller  4420  may control various operations of the scanner  4200 . 
     Herein, the controlling of the various operations of the scanner  4200  by the scan controller  4420  may mean generating at least one signal for controlling the various operations of the scanner  4200 , but is not limited thereto. 
     In addition, the detector controller  4430  may control various operations of the detector  4300 , and may process a signal acquired from the detector  4300 . 
     For example, the detector controller  4430  may control an operating voltage of the detector  4300 , but is not limited thereto. 
     In addition, for example, the detector controller  4430  may control the on/off operation of the detector  4300 , but is not limited thereto. 
     In addition, for example, the detector controller  4430  may determine a time point of acquisition of a signal acquired from the detector  4300 , but is not limited thereto. 
     In addition, for example, the detector controller  4430  may calculate a correction signal on the basis of a signal acquired from the detector  4300  so as to control a voltage applied to the detector  4300 , but is not limited thereto. 
     In addition, for example, the detector controller  4430  may calculate a distance offset on the basis of a signal acquired from the detector  4300 , but is not limited thereto. 
     In addition, for example, the detector controller  4430  may calculate a distance to an object on the basis of a signal acquired from the detector  4300 , but is not limited thereto. 
     In addition to the above-described details, the detector controller  4430  may control various operations of the detector  4300 , or may process a signal acquired from the detector  4300 . 
     Herein, the controlling of the various operations of the detector  4300  by the detector controller  4430  may mean generating at least one signal for controlling the various operations of the detector  4300 , but is not limited thereto. 
     In addition, the detector controller  4430  may include at least one of the following elements: a time counter  4431 , a correction signal calculator  4432 , a distance offset calculator  4433 , and a distance calculator  4434 . 
     Herein, the time counter  4431  may determine time on the basis of a signal acquired from the detector  4300 . 
     For example, the time counter  4431  may determine a time point at which a signal acquired from the detector  4300  is equal to or greater than a threshold (threshold value), but is not limited thereto. 
     In addition, the correction signal calculator  4432  may calculate a correction signal on the basis of a signal acquired from the detector  4300 . 
     For example, the correction signal calculator  4432  may calculate a correction signal on the basis of a difference between the width of a signal acquired from the detector  4300  and the width of a reference signal, and may use the correction signal to control a voltage applied to the detector  4300 . However, no limitation thereto is imposed. 
     In addition, the distance offset calculator  4433  may calculate an offset distance on the basis of a signal acquired from the detector  4300 . 
     For example, the distance offset calculator  4433  may calculate an offset distance on the basis of a time point at which a signal is acquired from the detector  4300  and reference distance information, but is not limited thereto. 
     In addition, the distance calculator  4434  may calculate a distance to an object on the basis of a signal acquired from the detector  4300 . 
     For example, the distance calculator  4434  may calculate a distance to an object on the basis of a time point at which a trigger signal is generated from the laser output controller  4410  and a time point at which a signal is acquired from the detector  4300 , but is not limited thereto. 
     In addition, for example, the distance calculator  4434  may calculate a distance to an object on the basis of a time point at which a trigger signal is generated from the laser output controller  4410 , a time point at which a signal is acquired from the detector  4300 , and an offset distance, but is not limited thereto. 
     In addition, the offset distance and the distance offset described above may be expressed as an offset time and a time offset. In a LiDAR device using a time value in order to calculate a distance to an object, calculating a final distance by using the offset distance and by using the offset time correspond to the same technical idea, so in the present specification and claims, descriptions using the terms “offset distance” and “offset time” may correspond to the same technical idea. 
     Hereinafter, the detailed operation of the correction signal calculator, the detailed operation of the distance offset calculator, and the detailed operation of the distance calculator will be described in more detail. 
       FIG.  23    is a diagram illustrating a correlation between a received signal gain and a measurement distance. 
     The gain of a received signal acquired from a detector included in a LiDAR device may be changed by various conditions. 
     For example, the gain of a received signal acquired from a detector included in a LiDAR device may be changed according to a distance to an item. 
     As a more specific example, the gain of a received signal acquired from a detector included in a LiDAR device may increase as a distance to an item decreases, or may decrease as the distance to the item increases. 
     In addition, for example, the gain of a received signal acquired from a detector included in a LiDAR device may be changed according to the reflectance of an item. 
     As a more specific example, the gain of a received signal acquired from a detector included in a LiDAR device may increase as the reflectance of an item increases, or may decrease as the reflectance of the item decreases. 
     In addition, for example, the gain of a received signal acquired from a detector included in a LiDAR device may be changed according to an operating condition of the detector. 
     As a more specific example, the gain of a received signal acquired from a detector included in a LiDAR device may be changed according to the temperature of the detector, but is not limited thereto. 
     In addition, for example, the gain of a received signal acquired from a detector included in a LiDAR device may be changed by a voltage applied to the detector. 
     As a more specific example, the gain of a received signal acquired from a detector included in a LiDAR device may increase as the voltage applied to the detector increases, or may decrease as the voltage applied to the detector decreases, but is not limited thereto. 
       FIG.  23    shows signals acquired with different gains for the same item as an example. 
     More specifically,  FIG.  23    shows a first signal  4510  according to a first gain, a second signal  4520  according to a second gain, and a third signal  4530  according to a third gain. 
     Herein, since the first to the third signals  4510  to  4530  are signals for the same item, it is desirable that the same distance is measured. However, when an algorithm for finding a time point of generation of a signal by using one threshold is applied, different distances may be measured. 
     For example, when a distance is calculated by applying the threshold to the first signal  4510 , the distance may be calculated on the basis of a first time value  4511 . When a distance is calculated by applying the threshold to the second signal  4520 , the distance may be calculated on the basis of a second time value  4521 . When a distance is calculated by applying the threshold to the third signal  4530 , the distance may be calculated on the basis of a third time value  4531 . 
     Accordingly, as shown in  FIG.  23   , since the first to the third time value  4511 ,  4521 , and  4531  are different from each other, distance values calculated on the basis of the first to the third time value  4511 ,  4521 , and  4531  may be different from each other. 
     As a result, in order for a LiDAR device to measure a more accurate distance, it may be important to reduce a factor that changes a gain value of a received signal. It may allow a distance to be more exactly measured to maintain the gain of the received signal by adjusting a voltage applied to the detector according to the operating condition of the detector. 
       FIG.  24    is a flowchart illustrating a method of calculating a compensation signal according to an embodiment.  FIG.  25    is a diagram illustrating a method of calculating a compensation signal according to an embodiment. 
     Referring to  FIG.  24   , a method of calculating a compensation signal according to an embodiment may include: positioning a scanner in a reference measurement position (S 4610 ); generating a trigger signal for laser output (S 4620 ); acquiring a measurement signal from a detector (S 4630 ); and calculating the compensation signal on the basis of the measurement signal and a reference signal (S 4640 ). 
     Herein, a method of calculating a compensation signal according to an embodiment may be realized by using a controller including at least one processor, but is not limited thereto. 
     The positioning the scanner in the reference measurement position (S 4610 ) according to an embodiment may comprise both generating a control signal to position the scanner in the reference measurement position and positioning the scanner in the reference measurement position during rotation. 
     Herein, the reference measurement position may mean a position of the scanner at which a laser output from a laser emitter is reflected from the scanner and reaches the above-described fixed mirror, and the details of the above-described reference measurement position may be applied to the position. 
     The generating the trigger signal for laser output (S 4620 ) according to an embodiment may be realized through the above-described laser output controller, but is not limited thereto. 
     In the acquiring the measurement signal from the detector (S 4630 ) according to an embodiment, the measurement signal acquired from the detector may be a signal for a laser that is output from the laser emitter and reflected from the scanner and the fixed mirror and received by the detector. 
     In addition, the acquiring the measurement signal from the detector (S 4630 ) according to an embodiment may comprise acquiring at least one measurement value for the measurement signal by using a threshold. 
     Herein, the at least one measurement value may include a time value of measurement of a rising edge of a signal, a time value of measurement of a falling edge of a signal, a width value of a signal, etc., but is not limited thereto. 
     The calculating the compensation signal on the basis of the measurement signal and the reference signal (S 4640 ) according to an embodiment may comprise calculating the compensation signal on the basis of the width of the measurement signal and the width of the reference signal. 
     For example, the calculating the compensation signal on the basis of the measurement signal and the reference signal (S 4640 ) according to an embodiment may comprise calculating the compensation signal on the basis of a difference value between the width of the measurement signal and the width of the reference signal, but is not limited thereto. 
     In addition, the calculating the compensation signal on the basis of the measurement signal and the reference signal (S 4640 ) according to an embodiment may comprise calculating the compensation signal on the basis of the size of the measurement signal and the size of the reference signal. 
     For example, the calculating the compensation signal on the basis of the measurement signal and the reference signal (S 4640 ) according to an embodiment may comprise calculating the compensation signal on the basis of a difference value between the size of the measurement signal and the size of the reference signal, but is not limited thereto. 
     In addition, when calculating the compensation signal on the basis of the measurement signal and the reference signal according to an embodiment, the reference signal may include a pre-acquired or stored signal, the width of the signal, the size of the signal, etc., but is not limited thereto. 
     In addition, the calculating the compensation signal on the basis of the measurement signal and the reference signal (S 4640 ) according to an embodiment will be described in detail with reference to  FIG.  25   . 
       FIG.  25    shows a reference signal  4710  according to an embodiment and a measurement signal  4720  according to an embodiment. 
     Herein, a width  4711  of the reference signal  4710  stored or calculated on the basis of a preset threshold (threshold value) may be different from a width  4721  of the measurement signal  4720  computed or calculated on the basis of the preset threshold. 
     Accordingly, a controller may adjust a voltage applied to a detector so that the width  4721  of the measurement signal (or measured signal)  4720  is equal to the width  4711  of the reference signal  4710 . 
     For example, the controller may calculate a compensation signal for adjusting a voltage applied to the detector, on the basis of a difference between the width  4721  of the measurement signal  4720  and the width  4711  of the reference signal  4710  so that the width  4721  of the measurement signal  4720  is equal to the width  4711  of the reference signal  4710 . 
     For example, a calculation formula for calculating the compensation signal may be as follows. 
       Compensation value=α×( T   PW     ref     −T   PW     meas   )
 
     Herein, T PW     ref    may mean the width  4711  of the reference signal  4710 , and T PW     meas    may mean the width  4721  of the measurement signal  4720 . 
     Furthermore, a may be a coefficient value, and may be a value calculated on the basis of experimental data. 
     Furthermore, a may have a unit of volt/sec, but is not limited thereto. 
     In addition, for example, the controller may calculate a compensation signal for adjusting a voltage applied to the detector, on the basis of a time value  4730  to be compensated for so that the width  4721  of the measurement signal  4720  can be equal to the width  4711  of the reference signal  4710 . 
     For example, a calculation formula for calculating the compensation signal may be as follows. 
       Compensation value=α× T   PWC  
 
     Herein, T PWC  may mean the time value  4730  to be compensated for, and the time value  4730  to be compensated for may be calculated on the basis of a difference between the width  4721  of the measurement signal  4720  and the width  4711  of the reference signal  4710 . 
     For example, a calculation formula for calculating the time value  4730  to be compensated for may be as follows. 
     
       
         
           
             
               T 
               PWC 
             
             = 
             
               
                 1 
                 2 
               
               ⁢ 
               
                 ( 
                 
                   
                     T 
                     
                       PW 
                       ref 
                     
                   
                   - 
                   
                     T 
                     
                       PW 
                       meas 
                     
                   
                 
                 ) 
               
             
           
         
       
     
     Furthermore, a may be a coefficient value, and may be a value calculated on the basis of experimental data. 
     Furthermore, a may have a unit of volt/sec, but is not limited thereto. 
       FIGS.  26 A and  26 B  are diagrams illustrating a correlation between a laser output trigger signal and an actual laser output time point. 
       FIG.  26 A  is a diagram schematically illustrating a laser output trigger signal, and  FIG.  26 B  is a diagram schematically illustrating a laser output time point according to operating conditions. 
     Referring to  FIG.  26 A , a laser output controller may generate a laser output trigger signal  4810  at a first time point. 
     Herein, after the laser output controller generates the laser output trigger signal  4810 , a laser emitter may acquire the laser output trigger signal  4810 , and then perform the operation for outputting a laser, and the laser emitter may output a laser after a particular delay from a time point of generation of the laser output trigger signal  4810  according to the configuration of the laser emitter. However, the particular delay may vary according to operating conditions of the laser emitter. 
     For example, referring to  FIG.  26 B , the laser emitter is in a first operating condition, a first laser  4820  may be output at a second time point. When the laser emitter is in a second operating condition, a second laser  4830  may be output at a third time point. When the laser emitter is in a third operating condition, a third laser  4840  may be output at a fourth time point. 
     Herein, the first to the third laser  4820 ,  4830 , and  4840  are just described to explain a difference between laser output time points under assumed operating conditions. When the laser output trigger signal  4810  is generated, if the operating condition of the laser emitter is the first operating condition, the first laser  4820  is output at the second time point, or if the operating condition of the laser emitter is the second operating condition, the second laser  4830  is output at the third time point, or if the operating condition of the laser emitter is the third operating condition, the third laser  4840  is output at the fourth time point. However, no limitation thereto is imposed. 
     As shown in  FIG.  26 B , a time point at which a laser is output from a laser emitter may vary according to the operating conditions of the laser emitter. 
     More specifically, when the laser emitter is in the first operating condition, the first laser  4820  may be output at the second time point after a first time interval  4821  from the time point of generation of the laser output trigger signal  4810 . When the laser emitter is in the second operating condition, the second laser  4830  may be output at the third time point after a second time interval  4831  from the time point of generation of the laser output trigger signal  4810 . When the laser emitter is in the third operating condition, the third laser  4840  may be output at the fourth time point after a third time interval  4841  from the time point of generation of the laser output trigger signal  4810 . 
     Herein, the first operating condition may be a reference operating condition and the second time point may be a laser output time point calculated or measured as a reference, but are not limited thereto. 
     As described above, in the case in which a laser output time point varies according to the operating conditions of the laser emitter, a distance error may occur when the LiDAR device calculates a distance to an object on the basis of a time point of generation of the laser output trigger signal  4810 . 
     So, in the related art, in order to solve this, a method of dividing and measuring a part of a laser output has been considered so as to directly detect a time point of generation of laser output. 
     However, dividing a part of a laser output as in the related art may decrease scan efficiency. 
     Accordingly, a method of acquiring an offset distance (correction distance) for reducing an error according to the operating conditions of the laser emitter may be important. 
     Hereinafter, a method of acquiring an offset distance will be described in more detail. 
       FIGS.  27 A through  27 C  are diagrams illustrating the operation of a distance offset calculator according to an embodiment. 
       FIG.  27 A  is a diagram schematically illustrating a laser output trigger signal.  FIG.  27 B  is a diagram schematically illustrating an output laser.  FIG.  27 C  is a diagram schematically illustrating a signal acquired from a detector. 
     Referring to  FIGS.  27 A through  27 C , a laser output controller may generate a laser output trigger signal  4910  at a first time point. 
     In addition, a laser  4920  may be output at a second time point after a first time interval  4921  from the first time point. 
     Herein, the first time interval  4921  may be changed according to the operating conditions of the laser emitter as described above. 
     In addition, the laser output from the laser emitter may be received along a preset light path by the detector. 
     Herein, the preset light path may mean a preset path from output of the laser from the laser emitter to reception by the detector. 
     For example, the preset light path may mean a light path along which a laser output from the laser emitter is reflected from the above-described scanner and reflected from the above-described fixed mirror and reflected again from the above-described scanner and received by the detector. However, the preset light path is not limited thereto, and may mean various paths pre-designed so that a laser output from the laser emitter is received by the detector. 
     In addition, after the laser  4920  is output from the laser emitter and a second time interval  4940  elapses, a signal  4930  for the laser  4920  may be acquired from the detector. 
     Herein, the second time interval  4940  may be a time interval corresponding to the preset light path. 
     For example, the second time interval  4940  may correspond to the time required for a laser to fly along the preset light path. 
     Therefore, the second time interval  4940  may correspond to a reference time interval, and the reference time interval may be a value calculated according to the designed preset light path or stored. 
     In addition, there is a third time interval  4931  between the time point of generation of the laser output trigger signal  4910  and the time point of acquisition of the signal  4930  by the detector. 
     Herein, the third time interval  4931  may correspond to a measured time interval. 
     For example, in the case in which in order to measure a distance to an object, a LiDAR device uses a time-of-flight (TOF) method using a time interval from a time point of generation of a laser output trigger signal to a time point of acquisition of a signal by a detection sensor, the third time interval  4931  may be a time interval measured for distance measurement. 
     As a result, referring to  FIGS.  27 A through  27 C , for exact calculation of a distance, the second time interval  4940  corresponding to the preset light path should be used for the calculation, but a measured time interval may be the third time interval  4931 , not the second time interval  4940 . 
     Accordingly, an offset as much as the first time interval  4921  may be generated according to the operating conditions of the laser emitter. The distance offset calculator may calculate the first time interval  4921  corresponding to the offset time (distance) on the basis of the third time interval  4931  corresponding to the measured time interval and the second time interval  4940  corresponding to the reference time interval. 
     Thus, the distance offset calculator may calculate an offset time (distance) by using the following equation. 
     
       
      
       T 
       offset 
       =T 
       meas 
       −T 
       ref  
      
     
     Herein, the T offset  may mean an offset time (distance), and may correspond to the first time interval  4921  according to the above description. 
     In addition, the T meas  may mean a measured time interval, and may correspond to the third time interval  4931  according to the above description. 
     In addition, the T ref  may mean a reference time interval, and may correspond to the second time interval  4940  according to the above description. 
       FIGS.  28 A through  28 C  are diagrams illustrating the operation of a distance offset calculator according to an embodiment. 
       FIG.  28 A  is a diagram schematically illustrating a laser output trigger signal.  FIG.  28 B  is a diagram schematically illustrating an output laser.  FIG.  28 C  is a diagram schematically illustrating a signal acquired from a detector. 
     Herein, in  FIGS.  28 A through  28 C , the pulses expressed in dotted lines may mean a first laser output when a laser emitter is in a first operating condition and a signal acquired from the detector for the first laser, and the pulses expressed in solid lines may mean a second laser output when the laser emitter is in a second operating condition and a signal acquired from a detection sensor for the second laser. 
     These will be described as a first laser  5020 , a second laser  5040 , a first detecting signal  5030 , and a second detecting signal  5050 . 
     The details described above with reference to  FIGS.  27 A through  27 C  may be applied to the details described with reference to  FIGS.  28 A through  28 C , so a redundant description will be omitted. 
     Referring to  FIGS.  28 A through  28 C , a laser output controller may generate a laser output trigger signal  5010  at a first time point. 
     In addition, when the laser emitter is in the first operating condition, the first laser  5020  may be output at a second time point after a first time interval  5021  from the first time point, and the first detecting signal  5030  for the first laser  5020  may be acquired by the detector at a third time point after the first laser  5020  is output and a second time interval  5060  elapses. 
     Herein, the first time interval  5021  may correspond to a first offset time (distance), and the second time interval  5060  may correspond to a reference time interval, and a third time interval  5031  may correspond to a first measured time interval. 
     In addition, when the laser emitter is in the second operating condition, the second laser  5040  may be output at a fourth time point after a fourth time interval  5041  from the first time point, and the second detecting signal  5050  for the second laser  5040  may be acquired by the detector at a fifth time point after the second laser  5040  is output and a fifth time interval  5070  elapses. 
     Herein, the fourth time interval  5041  may correspond to a second offset time (distance), and the fifth time interval  5070  may correspond to a reference time interval, and a sixth time interval  5051  may correspond to a second measured time interval. 
     Accordingly, referring to  FIG.  28   , an offset time (distance) may be changed according to the operating conditions of the laser emitter. 
     Thus, when the laser emitter operates under the first operating condition, the distance offset calculator may calculate an offset time (distance) by using the following equation. 
     
       
      
       T 
       offset 
       =T 
       meas1 
       −T 
       ref  
      
     
     Herein, the T offset  may mean a first offset time (distance), and may correspond to the first time interval  5021  according to the above description. 
     In addition, the T meas1  may mean a first measured time interval, and may correspond to the third time interval  5031  according to the above description. 
     In addition, the T ref  may mean a reference time interval, and may correspond to the second time interval  5060  according to the above description. 
     In addition, when the laser emitter operates under the second operating condition, the distance offset calculator may calculate an offset time (distance) by using the following equation. 
     
       
      
       T 
       offset2 
       =T 
       meas2 
       −T 
       ref  
      
     
     Herein, the T offset2  may mean a second offset time (distance), and may correspond to the fourth time interval  5041  according to the above description. 
     In addition, the T meas2  may mean a first measured time interval, and may mean the sixth time interval  5051  according to the above description. 
     In addition, the T ref  may mean a reference time interval, and may correspond to the fifth time interval  5070  according to the above description. 
     In addition, the operating conditions of the laser emitter may include a surrounding environment, such as the temperature of the laser emitter, etc. Therefore, the operating conditions of the laser emitter may be changed according to the driving of the LiDAR device. 
     Therefore, the operation of the distance offset calculator as described above is performed in real time or periodically, and when an offset time (distance) suitable for an operating condition of the laser emitter is calculated, an accurate distance may be continuously measured. 
       FIGS.  29 A through  29 C  are diagrams illustrating the operation of a distance offset calculator according to an embodiment. 
       FIG.  29 A  is a diagram schematically illustrating a laser output trigger signal.  FIG.  29 B  is a diagram schematically illustrating an output laser.  FIG.  29 C  is a diagram schematically illustrating a signal acquired from a detector. 
     Herein, the pulse expressed in a dotted line in  FIG.  29 C  may mean a signal having a reference reception gain, and the pulse expressed in a solid line may mean a signal actually acquired from the detector. 
     The details described above with reference to  FIG.  27 A  through  FIG.  28 C  may be applied to the details described with reference to  FIGS.  29 A through  29 C , so a redundant description will be omitted. 
       FIGS.  29 A through  29 C , a laser output controller may generate a laser output trigger signal  5110  at a first time point, and a laser  5120  may be output at a second time point after a first time interval  5121  from the first time point, and a detecting signal  5130  for the laser  5120  may be acquired from the detector at a third time point after the laser  5120  is output and a second time interval  5150  elapses. 
     Herein, the second time interval  5150  may be different from a reference time interval  5160 . 
     For example, the reference time interval  5160  may be a time interval when a reference detecting signal  5140  is acquired from the detector after the laser  5120  is output. When the detecting signal  5130  different from the reference detecting signal  5140  is acquired from the detector, the second time interval  5150  may be different from the reference time interval  5160 . 
     Accordingly, when the operation of a compensation signal calculator described above with reference to  FIGS.  23  to  25    is applied in order to maintain the reception gain of the detector, compensation for as much as a fourth time interval  5170  is performed twice and an error may occur, wherein the fourth time interval  5170  is the difference between the second time interval  5150  and the reference time interval  5160 . 
     Thus, the distance offset calculator may calculate an offset time (distance) by using the following equation. 
     
       
      
       T 
       offset 
       =T 
       meas 
       −T 
       ref 
       −T 
       pwc  
      
     
     Herein, the T offset  may mean an offset time (distance), and may correspond to the first time interval  5121  according to the above description. 
     In addition, the T meas  may mean a measured time interval, and may correspond to the third time interval  5131  according to the above description. 
     In addition, the T ref  may mean a reference time interval, and may correspond to the reference time interval  5160  according to the above description. 
     In addition, the T pwc  may mean a time value to be compensated for, and may correspond to the fourth time interval  5170  according to the above description. 
     In addition, the sum of the T ref  and the T pwc  may correspond to the second time interval  5150  according to the above description. 
       FIGS.  30  and  31    are flowcharts illustrating a method for operating a LiDAR device according to an embodiment. 
     Referring to  FIGS.  30  and  31   , a method for operating a LiDAR device according to an embodiment may comprise at least part of the following: positioning a scanner in a first reference measurement position (S 5210 ); acquiring a first detecting signal for an outputted laser when the scanner is located in the first reference measurement position (S 5220 ); acquiring a first compensation signal and first offset distance information based on the first detecting signal (S 5230 ); changing a voltage applied to a detector to a first voltage based on the first compensation signal (S 5240 ); positioning the scanner in a first scan position (S 5250 ); acquiring a second detecting signal for the outputted laser when the scanner is located in the first scan position (S 5260 ); calculating first distance information based on the first offset distance information and the second detecting signal (S 5270 ); positioning the scanner in a second reference measurement position (S 5310 ); acquiring a third detecting signal for the outputted laser when the scanner is located in the second reference measurement position (S 5320 ); acquiring second offset distance information and a second compensation signal based on the third detecting signal (S 5330 ); changing the voltage applied to the detector to a second voltage based on the second compensation signal (S 5340 ); positioning the scanner in the second scan position (S 5350 ); acquiring a fourth detecting signal for the outputted laser when the scanner is located in the second scan position (S 5360 ); and calculating the second distance information based on the fourth detecting signal and the second offset distance information (S 5370 ). 
     Herein, a method for operating a LiDAR device according to an embodiment may be realized by using a controller including at least one processor, but is not limited thereto. 
     The positioning the scanner in the first reference measurement position (S 5210 ) according to an embodiment may be realized by the above-described scan controller, but is not limited thereto. 
     In addition, the positioning the scanner in the first reference measurement position (S 5210 ) according to an embodiment may include both generating a control signal to position the scanner in the first reference measurement position and positioning the scanner in the first reference measurement position during rotation. 
     Herein, the first reference measurement position may mean at least one of the positions of the scanner in which a laser output from a laser emitter is received by the detector along a preset reference light path, but is not limited thereto. 
     In addition, the acquiring the first detecting signal for the outputted laser when the scanner is located in the first reference measurement position (S 5220 ) according to an embodiment may be realized by the above-described detector controller, but is not limited thereto. 
     Herein, the first detecting signal may be a signal for a laser that is output from the laser emitter and reflected from the scanner and a fixed mirror and received by the detector, but is not limited thereto. 
     In addition, the acquiring the first detecting signal for the outputted laser when the scanner is located in the first reference measurement position (S 5220 ) according to an embodiment may include acquiring at least one measurement value for the first detecting signal by using a threshold. 
     Herein, the at least one measurement value may include a time value of measurement of a rising edge of a signal, a time value of measurement of a falling edge of a signal, a width value of a signal, etc., but is not limited thereto. 
     In addition, the acquiring the first compensation signal and the first offset distance information based on the first detecting signal (S 5230 ) according to an embodiment may be realized by the above-described detector controller, but is not limited thereto. 
     In addition, the details described above with reference to  FIGS.  23  to  29    may be applied to the acquiring the first compensation signal and the first offset distance information based on the first detecting signal (S 5230 ) according to an embodiment, so a redundant description will be omitted. 
     In addition, the changing the voltage applied to the detector to the first voltage based on the first compensation signal (S 5240 ) according to an embodiment may be realized by the above-described detector controller, but is not limited thereto. 
     In addition, the details described above with reference to  FIGS.  23  to  25    may be applied to the changing the voltage applied to the detector to the first voltage based on the first compensation signal (S 5240 ) according to an embodiment, so a redundant description will be omitted. 
     In addition, the positioning the scanner in the first scan position (S 5250 ) according to an embodiment may be realized by the above-described scan controller, but is not limited thereto. 
     In addition, the positioning the scanner in the first scan position (S 5250 ) according to an embodiment may comprise both generating a control signal to position the scanner in the first scan position and positioning the scanner in the first scan position during rotation. 
     Herein, the first scan position may mean at least one of the positions of the scanner in which a laser output from the laser emitter is emitted to the outside of the LiDAR device, but is not limited thereto. 
     In addition, the acquiring the second detecting signal for the outputted laser when the scanner is located in the first scan position (S 5260 ) according to an embodiment may be realized by the above-described detector controller, but is not limited thereto. 
     Herein, the second detecting signal may be a signal for a laser that is output from the laser emitter and reflected from an object outside the LiDAR device and received by the detector, but is not limited thereto. 
     In addition, the acquiring the second detecting signal for the outputted laser when the scanner is located in the first scan position (S 5260 ) according to an embodiment may comprise acquiring at least one measurement value for the second detecting signal by using the threshold. 
     Herein, the at least one measurement value may include a time value of measurement of a rising edge of a signal, a time value of measurement of a falling edge of a signal, a width value of a signal, etc., but is not limited thereto. 
     In addition, the calculating the first distance information based on the first offset distance information and the second detecting signal (S 5270 ) according to an embodiment may be realized by the above-described detector controller, but is not limited thereto. 
     In addition, in the calculating the first distance information based on the first offset distance information and the second detecting signal (S 5270 ) according to an embodiment, a difference between a time point of detection of the second detecting signal and a first offset time corresponding to the first offset distance may be used to calculate the first distance information. 
     More specifically, the following equations may be used to calculate the first distance information. 
     
       
         
           
             
               d 
               
                 obj 
                 meas 
               
             
             - 
             
               d 
               offset 
             
           
         
       
       
         
           
             
               d 
               obj 
             
             = 
             
               
                 1 
                 2 
               
               × 
               C 
               × 
               
                 ( 
                 
                   
                     T 
                     
                       obj 
                       meas 
                     
                   
                   - 
                   
                     T 
                     offset 
                   
                 
                 ) 
               
             
           
         
       
     
     Herein, the d obj  may mean a distance to an object, and may correspond to the first distance information according to the above description. 
     In addition, the d obj     meas    may mean a distance calculated on the basis of a detecting signal, and may mean a distance calculated on the basis of the second detecting signal according to the above description. 
     In addition, the d offset  may mean an offset distance, and may correspond to a first offset distance according to the above description. 
     In addition, the T obj     meas    may correspond to a time point at which a detecting signal is detected, and may correspond to the time point at which the second detecting signal is detected according to the above description. 
     In addition, the T offset  may mean an offset time, and may correspond to a first offset time according to the above description. 
     In addition, the positioning the scanner in the second reference measurement position (S 5310 ) according to an embodiment may be realized by the above-described scan controller, but is not limited thereto. 
     In addition, the positioning the scanner in the second reference measurement position (S 5310  according to an embodiment may include both generating a control signal to position the scanner in the second reference measurement position and positioning the scanner in the second reference measurement position during rotation. 
     Herein, the second reference measurement position may mean at least one of the positions of the scanner in which a laser output from the laser emitter is received by the detector along the preset reference light path, but is not limited thereto. 
     In addition, the acquiring the third detecting signal for the outputted laser when the scanner is located in the second reference measurement position (S 5320 ) according to an embodiment may be realized by the above-described detector controller, but is not limited thereto. 
     Herein, the third detecting signal may be a signal for a laser that is output from the laser emitter and reflected from the scanner and the fixed mirror and received by the detector, but is not limited thereto. 
     In addition, the acquiring the third detecting signal for the outputted laser when the scanner is located in the second reference measurement position (S 5320 ) according to an embodiment may comprise acquiring at least one measurement value for the third detecting signal by using the threshold. 
     Herein, the at least one measurement value may include a time value of measurement of a rising edge of a signal, a time value of measurement of a falling edge of a signal, a width value of a signal, etc., but is not limited thereto. 
     In addition, the acquiring the second offset distance information and the second compensation signal based on the third detecting signal (S 5330 ) according to an embodiment may be realized by the above-described detector controller, but is not limited thereto. 
     In addition, the details described above with reference to  FIGS.  23  to  29    may be applied to the acquiring the second offset distance information and the second compensation signal based on the third detecting signal (S 5330 ) according to an embodiment, so a redundant description will be omitted. 
     In addition, the changing the voltage applied to the detector to the second voltage based on the second compensation signal (S 5340 ) according to an embodiment may be realized by the above-described detector controller, but is not limited thereto. 
     In addition, the details described above with reference to  FIGS.  23  to  25    may be applied to the changing the voltage applied to the detector to the second voltage based on the second compensation signal (S 5340 ) according to an embodiment, so a redundant description will be omitted. 
     In addition, the positioning the scanner in the second scan position (S 5350 ) according to an embodiment may be realized by the above-described scan controller, but is not limited thereto. 
     In addition, the positioning the scanner in the second scan position (S 5350 ) according to an embodiment may include both generating a control signal to position the scanner in the second scan position and positioning the scanner in the second scan position during rotation. 
     Herein, the second scan position may mean at least one of the positions of the scanner in which a laser output from the laser emitter is emitted to the outside of the LiDAR device, but is not limited thereto. 
     In addition, the acquiring the fourth detecting signal for the outputted laser when the scanner is located in the second scan position (S 5360 ) according to an embodiment may be realized by the above-described detector controller, but is not limited thereto. 
     Herein, the fourth detecting signal may be a signal for a laser that is output from the laser emitter and reflected from an object outside the LiDAR device and received by the detector, but is not limited thereto. 
     In addition, the acquiring the fourth detecting signal for the outputted laser when the scanner is located in the second scan position (S 5360 ) according to an embodiment may comprise acquiring at least one measurement value for the fourth detecting signal by using the threshold. 
     Herein, the at least one measurement value may include a time value of measurement of a rising edge of a signal, a time value of measurement of a falling edge of a signal, a width value of a signal, etc., but is not limited thereto. 
     In addition, the calculating the second distance information based on the fourth detecting signal and the second offset distance information (S 5370 ) according to an embodiment may be realized by the above-described detector controller, but is not limited thereto. 
     In addition, in the calculating the second distance information based on the fourth detecting signal and the second offset distance information (S 5370 ) according to an embodiment, a difference between a time point of detection of the fourth detecting signal and a second offset time corresponding to the second offset distance may be used to calculate the second distance information. 
     More specifically, the following equations may be used to calculate the second distance information. 
     
       
         
           
             
               d 
               
                 obj 
                 meas 
               
             
             - 
             
               d 
               offset 
             
           
         
       
       
         
           
             
               d 
               obj 
             
             = 
             
               
                 1 
                 2 
               
               × 
               C 
               × 
               
                 ( 
                 
                   
                     T 
                     
                       obj 
                       meas 
                     
                   
                   - 
                   
                     T 
                     offset 
                   
                 
                 ) 
               
             
           
         
       
     
     Herein, the d obj  may mean a distance to an object, and may correspond to the second distance information according to the above description. 
     In addition, the d obj     meas    may mean a distance calculated on the basis of a detecting signal, and may mean a distance calculated on the basis of the fourth detecting signal according to the above description. 
     In addition, the d offset  may mean an offset distance, and may correspond to a second offset distance according to the above description. 
     In addition, the T obj     meas    may correspond to a time point at which a detecting signal is detected, and may correspond to the time point at which the fourth detecting signal is detected according to the above description. 
     In addition, the T offset  may mean an offset time, and may correspond to a second offset time according to the above description. 
     In addition, the first reference measurement position may be identical to the second reference measurement position. 
     In addition, the first reference measurement position and the second reference measurement position may be different from each other. 
     In addition, the first scan position may be identical to the second scan position. 
     In addition, the first scan position and the second scan position may be different from each other. 
     In addition, the first voltage may be identical to the second voltage. 
     In addition, the first voltage and the second voltage may be different from each other. 
     In addition, the first offset distance information may be identical to the second offset distance information. 
     In addition, the first offset distance information and the second offset distance information may be different from each other. 
     In addition, when the first scan position is identical to the second scan position and the first offset distance information is different from the second offset distance information, the time point at which the second detecting signal is detected may be different from the time point at which the fourth detecting signal is detected. 
     In addition, when the first scan position is identical to the second scan position and the first offset distance information is identical to the second offset distance information, the time point at which the second detecting signal is detected may be identical to the time point at which the fourth detecting signal is detected. 
       FIGS.  32 A and  32 B  are diagrams illustrating comparison between measurement results according to an embodiment. 
       FIG.  32 A  is a diagram illustrating a measurement result when a correction signal calculator and a distance offset calculator according to the present disclosure did not operate.  FIG.  32 B  is a diagram illustrating a measurement result when the correction signal calculator and the distance offset calculator according to the present disclosure operated. 
     In addition,  FIGS.  32 A and  32 B  are diagrams illustrating the results measured in an environment with a wall in a straight line to the left. 
     Referring to  FIGS.  32 A and  32 B , it is found that when the correction signal calculator and the distance offset calculator according to the present disclosure did not operate, there was a large error in a distance to the wall in the straight line to the left. However, it is found that when the correction signal calculator and the distance offset calculator according to the present disclosure operated, an error in the distance to the wall in the straight line to the left was significantly reduced. 
     Accordingly, when the operations of the LiDAR device described above in the present specification are applied, it is possible to reduce a distance error caused by a change in operating conditions of the LiDAR device, thereby measuring a distance effectively and more accurately. 
     Methods according to the embodiments may be embodied as program commands executable by various computer means and may be recorded on a computer-readable recording medium. The computer-readable recording medium may include program commands, data files, data structures, and the like separately or in combinations. The program commands to be recorded on the computer-readable recording medium may be specially designed and configured for the embodiments may be well-known to and be usable by those skilled in the art of computer software. Examples of the computer-readable recording medium include magnetic recording media such as hard disks, floppy disks and magnetic tapes; optical data storage media such as CD-ROMs or DVD-ROMs; magneto-optical media such as floptical disks; and hardware devices, such as read-only memory (ROM), random-access memory (RAM), and flash memory, which are particularly structured to store and implement the program instruction. Examples of the program instructions include not only a mechanical language code formatted by a compiler but also a high level language code that may be implemented by a computer using an interpreter, and the like. The hardware devices may be configured to be operated by one or more software modules or vice versa to conduct the operation according to the embodiments. 
     Although the embodiments have been described with reference to the limited embodiments and drawings, it will be understood by those skilled in the art that various modifications and variations may be made from the description. For example, suitable results may be achieved if the described techniques are performed in an order different from the described method, and/or the elements of the above-described system, structure, device, and circuit are coupled or combined in a form different from the described method, or replaced or substituted by other elements or equivalents. 
     Therefore, other implementations, other embodiments, and equivalents to the claims are also within the scope of the following claims.