Distance measuring device and method of measuring distance by using the same

Abstract

A light detection and ranging (LiDAR) device and a method for using the same are provided. The LiDAR device includes: a light scanner configured to periodically scan an area in a surrounding area by sequentially changing a travel path of incident light; a first light source configured to provide first light to the light scanner in a first incident direction; and a second light source configured to provide second light to the light scanner in a second incident direction different from the first incident direction.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is based on and claims the benefit of priority from Korean Patent Application No. 10-2019-0118377 filed in the Korean Intellectual Property Office on September 25, 2019, the disclosure of which is incorporated herein in its entirety by reference. Technical Field

[0003] The present disclosure relates to a distance measuring device for measuring a distance and a method of measuring a distance by using the distance measuring device. Background Art

[0004] Recently, research has been underway into 3D cameras and Light Detection and Ranging (LIDAR) technology for measuring the distance to an object. One distance measurement technology is the Time of Flight (TOF) method, which measures the time it takes light to travel between an object and a camera. The TOF method is capable of measuring the distance between an image capture device and an object (hereinafter referred to as a depth image).

[0005] The TOF method basically includes the following process: irradiating light of a specific wavelength (e.g., near-infrared light (850 nm)) toward an object using a light-emitting diode (LED) or a laser diode (LD), measuring or capturing an image corresponding to the light of the specific wavelength reflected by the object using a photodiode or a camera, and extracting a depth image from the measured or captured image. Various TOF methods have been disclosed regarding optical processing, i.e., a series of processes including light irradiation, reflection at an object, optical modulation, image capture, and processing. However, methods for more accurately measuring the distance to an object in an improved manner are underway. Summary of the Invention

[0006] Provided are a light detection and ranging (LiDAR) device capable of improving crosstalk and a method of using the LiDAR device to more accurately measure a distance to an object.

[0007] Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments of the disclosure.

[0008] According to one aspect of the embodiments, there is provided a light detection and ranging (LiDAR) device, comprising: a light scanner configured to periodically scan an area in a surrounding area by sequentially changing a travel path of incident light; a first light source configured to provide first light to the light scanner in a first incident direction; and a second light source configured to provide second light to the light scanner in a second incident direction different from the first incident direction, and wherein the light scanner is further configured to scan the area in the surrounding area multiple times using the first light and the second light during one scanning cycle of the light scanner.

[0009] The first light source and the second light source may be configured to intermittently provide the first light and the second light to the light scanner.

[0010] The first light source and the second light source may be configured to provide the first light and the second light to the light scanner simultaneously or alternately.

[0011] The light scanner may also be configured to sequentially change a travel path of the incident light by rotating the light scanner with respect to a central axis of the light scanner.

[0012] A scanning period of the optical scanner may be less than or equal to a rotation period of the optical scanner.

[0013] The light scanner may include a plurality of reflective surfaces, and each of the plurality of reflective surfaces may be parallel to a central axis of the light scanner or may be inclined with respect to the central axis of the light scanner.

[0014] A first reflective surface among the plurality of reflective surfaces may have a first inclination angle, and a second reflective surface among the plurality of reflective surfaces may have a second inclination angle different from the first inclination angle.

[0015] Adjacent reflecting surfaces among the plurality of reflecting surfaces may have different inclination angles.

[0016] The second light source may be configured to emit the second light to a second reflective surface different from a first reflective surface among the plurality of reflective surfaces, while the first light source is configured to provide the first light to the first reflective surface among the plurality of reflective surfaces.

[0017] The first reflecting surface may scan a first sub-region of the area in the surrounding area by sequentially reflecting the first light in different directions, and the second reflecting surface may scan a second sub-region of the area in the surrounding area that is different from the first sub-region by sequentially reflecting the second light in different directions.

[0018] The first sub-region and the second sub-region may not overlap with each other.

[0019] The first sub-area and the second sub-area may be arranged parallel to a rotation axis of the light scanner.

[0020] The LiDAR device may further include: a light receiver configured to detect third light reflected in the area of ​​the surrounding area from the first light and fourth light reflected in the area of ​​the surrounding area from the second light; and a processor configured to acquire a frame including depth information of the area of ​​the surrounding area by using a detection result from the light receiver.

[0021] The processor can also be configured to: obtain a first initial frame corresponding to the first light including depth information of the area of ​​the surrounding area and a second initial frame corresponding to the second light including depth information of the area of ​​the surrounding area in the detection results from the light receiver, and use the first initial frame and the second initial frame to obtain the frame.

[0022] The processor may be further configured to obtain the frame by applying correlation to the first initial frame and the second initial frame.

[0023] The processor may also be configured to: acquire a third initial frame including depth information of the area in the surrounding area by using a detection result from the light receiver during a first time, acquire a fourth initial frame including depth information of the area in the surrounding area by using a detection result from the light receiver during a second time after the first time, and acquire the frame using the third initial frame and the fourth initial frame.

[0024] Each of the third initial frame and the fourth initial frame may include depth information corresponding to both the first light and the second light.

[0025] The first time and the second time may be equal to 1 / 2 of a scanning period of the optical scanner.

[0026] According to another aspect of the embodiment, a method for operating a light detection and ranging (LiDAR) device is provided, the method comprising: providing first light and second light to a light scanner; and scanning, by the light scanner, an area in a surrounding area multiple times using the first light and the second light during one scanning cycle of the light scanner by sequentially changing travel paths of the first light and the second light, wherein the scanning comprises: scanning a second sub-area of ​​the area in the surrounding area that does not overlap with the first sub-area of ​​the area in the surrounding area using the second light, while scanning the first sub-area of ​​the area in the surrounding area using the first light.

[0027] The scanning may further include scanning the second sub-area using the first light while scanning the first sub-area using the second light.

[0028] The providing may include providing the first light to the light scanner in a first incident direction, and providing the second light to the light scanner in a second incident direction different from the first incident direction.

[0029] The providing may include simultaneously or alternately providing the first light and the second light to the light scanner.

[0030] The method may further include: detecting third light reflected in the area in the surrounding area from the first light and fourth light reflected in the area in the surrounding area from the second light; and acquiring a frame including depth information of the area in the surrounding area by using the detection result.

[0031] Acquiring the frame may include: acquiring a first initial frame corresponding to the first light and including depth information of the area in the surrounding area, and a second initial frame corresponding to the second light and including depth information of the area in the surrounding area in the detection result; and acquiring the frame using the first initial frame and the second initial frame.

[0032] The frame may be obtained by applying correlation to the first initial frame and the second initial frame.

[0033] According to another aspect of the embodiment, a device is provided, including: a memory configured to store one or more instructions; and a processor configured to execute the one or more instructions to: detect first reflected light reflected in an area in a surrounding area from first emitted light; detect second reflected light reflected in the area in the surrounding area from second emitted light; and acquire a frame including depth information of the area in the surrounding area based on the detected first reflected light and the detected second reflected light.

[0034] The processor can also be configured to: obtain a first initial frame corresponding to the first reflected light, including depth information of the area in the surrounding area; obtain a second initial frame corresponding to the second reflected light, including depth information of the area in the surrounding area; and obtain the frame based on the first initial frame and the second initial frame.

[0035] The processor may be further configured to obtain the frame by applying correlation to the first initial frame and the second initial frame.

[0036] The processor can also be configured to: output a first signal to control the light scanner to periodically scan the area in the surrounding area multiple times during one scanning cycle of the light scanner by sequentially changing the incident travel paths of the first emitted light and the second emitted light; output a second signal to control the first light source to provide the first emitted light to the light scanner in a first incident direction; and output a third signal to control the second light source to provide the second emitted light to the light scanner in a second incident direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The above and other aspects, features and advantages of certain embodiments of the present disclosure will become more apparent from the following description taken in conjunction with the accompanying drawings, in which:

[0038] Figure 1 is a block diagram illustrating an example of a light detection and ranging (LiDAR) device according to an embodiment;

[0039] Figure 2 is a diagram illustrating an example scenario in which a LiDAR device operates;

[0040] Figure 3 is a block diagram illustrating a light emitter that radiates multiple lights according to an embodiment;

[0041] Figure 4 is a reference diagram illustrating a mechanical optical scanner according to an embodiment;

[0042] Figure 5A yes Figure 4 A cross-sectional view of an optical scanner;

[0043] Figure 5B It is shown that the Figure 4 A diagram showing an example of a tilt angle of a reflective surface in a light scanner;

[0044] Figure 6A 、 Figure 6B and Figure 6C is a reference diagram illustrating a scanning method performed by an optical scanner during one scanning cycle according to an embodiment;

[0045] Figure 7 is a diagram showing an optical scanner including an optical phased array according to an embodiment;

[0046] Figure 8 is a diagram showing an example of an optical receiver according to an embodiment;

[0047] Figure 9 is a diagram illustrating a method of acquiring a frame according to an embodiment;

[0048] Figure 10 is a reference diagram illustrating a method of acquiring a frame according to an embodiment;

[0049] Figure 11 is a reference diagram illustrating a method of acquiring a frame according to another embodiment;

[0050] Figure 12 is a flowchart illustrating a method of acquiring a frame according to another embodiment;

[0051] Figure 13 It shows Figure 12 Reference diagram of the method for obtaining frames;

[0052] Figure 14 is a reference diagram illustrating a frame acquisition method for increasing temporal resolution according to an embodiment; and

[0053] Figure 15 is a reference diagram illustrating a method of acquiring a frame with increased temporal resolution according to another embodiment. DETAILED DESCRIPTION

[0054] Hereinafter, specific embodiments will be described in detail with reference to the accompanying drawings. It should be understood that the following description is intended to illustrate specific embodiments, rather than to restrict or limit the scope of the present disclosure. It should be understood that those skilled in the art can easily infer from the detailed description, and the embodiments fall within the scope of the present disclosure.

[0055] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. Expressions such as "at least one of..." when following a list of elements modify the entire list of elements and do not modify the individual elements of the list.

[0056] As used herein, the terms "include" or "comprising" should not be interpreted as necessarily including various elements or operations described in the specification, but should be interpreted as not including some elements or operations, or further including additional elements or operations. As used herein, the terms "unit", "module" and the like should be understood as units for processing at least one function or operation, and may be embodied in hardware, software, or a combination thereof.

[0057] Although the terms "first," "second," etc. may be used herein to describe various components, these components should not be limited by these terms. These terms are only used to distinguish one component from another.

[0058] Figure 1 is a block diagram illustrating an example of a light detection and ranging (LiDAR) apparatus 100 according to an embodiment.

[0059] The LiDAR device 100 may be used as a sensor that acquires three-dimensional (3D) information such as distance information about an object 10 in real time. For example, the LiDAR 100 may be applied to or used in unmanned vehicles, autonomous cars, robots, and drones. Figure 1 The LiDAR device 100 may include: a light emitter 110 that radiates light L toward a surrounding area; a light receiver 120 that receives light L′ reflected from a surrounding area of ​​the light radiated toward the surrounding area; and a processor 130 that uses an electrical signal corresponding to the received light to obtain a frame including distance information about an object 10 present in the surrounding area. According to an embodiment, the received light L′ corresponds to the light L radiated from the light emitter 110 onto the object 10.

[0060] The LiDAR device 100 can be implemented as a housing or as multiple housings. When the LiDAR device 100 is implemented as multiple housings, the multiple components can be connected in a wired manner or can be connected wirelessly. For example, the LiDAR device 100 can be divided into a first device including the light transmitter 110 and the light receiver 120 and a second device including the processor 130. The LiDAR device 100 can also be implemented as a component of a device for performing another function, such as an autonomous driving device.

[0061] Although Figure 1 The LiDAR device 100 only shows elements related to a specific embodiment of the present disclosure, but a person skilled in the art will understand that the device may also include elements other than Figure 1 Common elements other than those shown. For example, the LiDAR device 100 may further include a memory or a communication interface.

[0062] According to an embodiment, the memory is hardware that stores various data processed in the LiDAR device 100. For example, the memory can store data processed in the LiDAR device 100 and data to be processed. In addition, the memory can store applications, drivers, etc. to be driven by the LiDAR device 100.

[0063] The memory may be a random access memory (RAM) such as a dynamic random access memory (DRAM), a static random access memory (SRAM), a read-only memory (ROM), an electrically erasable programmable read-only memory (EEPROM), a CD-ROM, a Blu-ray or other optical disk storage device, a hard disk drive (HDD), a solid-state drive (SSD), or flash memory, and may also include other external storage devices that can be accessed by the LiDAR device 100.

[0064] According to an embodiment, the communication interface may include one or more hardware components that facilitate communication between the LiDAR device 100 and an external device.

[0065] Figure 2 is a diagram showing an example scenario in which the LiDAR device 100a operates. i Then, the object C3 existing in the surrounding area can react to the radiated light L i is reflected, and the LiDAR device 100a can detect the reflected light L i '.

[0066] Meanwhile, the LiDAR device 100a can detect not only the light radiated by the LiDAR device 100a and reflected to the LiDAR device 100a, but also other light L incident from the outside. o '. When other light L o ' has a wavelength different from the light L radiated from the LiDAR device 100a i When the wavelength of other light L o ' can be easily removed by a band filter. However, when the light L o When it is light emitted from another LiDAR device 100b and is similar in light characteristics to the LiDAR device 100a according to the embodiment, it may be difficult to remove the light L by the band filter. o ', and light L o 'May cause crosstalk.

[0067] The LiDAR apparatus 100 according to an embodiment may acquire a frame with improved crosstalk by scanning a surrounding area using a plurality of lights.

[0068] Figure 3 is a block diagram illustrating a light emitter 110 that radiates a plurality of lights according to an embodiment. Figure 3 , the light emitter 110 of the LiDAR device 100 may include a first light source 210 that provides a first light L1, a second light source 230 that provides a second light L2, and a light scanner 250 that periodically scans a surrounding area by sequentially changing a travel path of the incident lights L1 and L2 over time.

[0069] Each of the first light source 210 and the second light source 230 may be a device that radiates light in the infrared range. When using light in the infrared range, it is possible to prevent the infrared light from mixing with natural light in the visible light range, including sunlight. However, the present disclosure is not necessarily limited thereto, and the light emitter 110 may include a light source that radiates light in various wavelength bands, or may radiate light in multiple different wavelength bands. In addition, the light emitter 110 may radiate pulsed light or continuous light.

[0070] Each of the first and second light sources 210 and 230 may include a light source such as a laser diode (LD), an edge emitting laser, a vertical cavity surface emitting laser (VCSEL), a distributed feedback laser, a light emitting diode (LED), and a superluminescent diode (SLD), but is not limited thereto.

[0071] Depending on the embodiment, the first light source 210 and the second light source 230 may radiate or provide light having the same optical characteristics to the light scanner 250, or may radiate or provide light having different optical characteristics to the light scanner 250. Herein, optical characteristics may refer to the waveform, period, duty cycle, etc. of the light. For example, the first light source 210 and the second light source 230 may provide a first pulse-shaped light L1 and a second pulse-shaped light L2. The first light L1 and the second light L2 may have the same pulse period but different duty cycles.

[0072] According to an embodiment, the first light source 210 and the second light source 230 may simultaneously and alternately provide the first light L1 and the second light L2 to the light scanner 250 .

[0073] According to one embodiment, the first light source 210 and the second light source 230 may provide the first light L1 and the second light L2 to the light scanner 250 in different incident directions. According to another embodiment, the first light source 210 and the second light source 230 may provide the first light L1 and the second light L2 with different phases to the light scanner 250. Therefore, the light scanner 250 can scan different areas of the surrounding area by differently changing the travel paths of the first light L1 and the second light L2.

[0074] The light scanner 250 can sequentially change the first light L provided from the first light source 210 and the second light source 230. lThe light scanner 250 can change the travel paths of the first light L1 and the second light L2 over time to scan a specific range of the surrounding area. The specific range can be predetermined. The specific range can be determined as the scanning range that the light scanner 250 can scan based on the light steering angle of the light scanner 250. The light scanner 250 can change the travel paths of the first light L1 and the second light L2 by reflecting the incident first light L1 and the second light L2 or by modulating the phases of the first light L1 and the second light L2. According to an embodiment, during one scanning cycle, the light scanner 250 can use the first light L1 and the second light L2 to scan the scanning range 11 (such as Figure 4 shown) are scanned twice.

[0075] Although according to Figure 3 The embodiment in FIG. 1 shows two lights, but the present disclosure is not limited thereto. The LiDAR device 100 according to another embodiment may provide three or more lights. In addition, the light scanner 250 may scan a predetermined range, i.e., the scanning range 11, according to the number of lights provided during one scanning cycle. For example, when three lights are provided to the light scanner 250, the light scanner 250 may scan the scanning range 11 three times during one scanning cycle. According to another embodiment, when M lights are provided, the light scanner 250 may scan the scanning range 11 M times during one scanning cycle, where M is a natural number.

[0076] Figure 4 2 is a reference diagram illustrating a mechanical optical scanner 250a according to an embodiment. Figure 4 As shown, light scanner 250a can have an asymmetric shape relative to the central axis (z-axis) of light scanner 250a. For example, light scanner 250a can include multiple reflective surfaces 251 (251-1 to 251-8) that are parallel to or tilted relative to the central axis (z-axis). At least two of the multiple reflective surfaces 251 can have different tilt angles relative to the central axis (z-axis). For example, adjacent reflective surfaces 251-1 and 251-7 among the multiple reflective surfaces 251 can have different tilt angles relative to the central axis (z-axis). Alternatively, each of the multiple reflective surfaces 251 can have a different tilt angle.

[0077] The optical scanner 250a can scan the surrounding area by rotating about a central axis. The scanning period of the optical scanner 250a can be determined by the rotation period of the optical scanner 250a. For example, the scanning period of the optical scanner 250a can be the same as the rotation period of the optical scanner 250a, but is not limited thereto. The scanning period of the optical scanner 250a can be 1 / N of the rotation period of the optical scanner 250a. N can be the number of reflective surfaces 251 having the same tilt angle, where N is a natural number.

[0078] Figure 5A yes Figure 4A cross-sectional view of the optical scanner 250a, Figure 5B : is a diagram showing an example of the tilt angle of the reflective surface 251 of the light scanner 250a. Figure 5A and Figure 5B As shown, the cross section parallel to the central axis (z-axis) of the light scanner 250a may have a cylindrical shape, but is not limited thereto. The cross section parallel to the central axis (z-axis) of the light scanner 250a may be a trumpet shape, etc. The cross section perpendicular to the central axis (z-axis) of the light scanner 250a may be a polygon, but is not limited thereto. The cross section perpendicular to the central axis (z-axis) of the light scanner 250a may include a curve. At least two of the reflective surfaces 251 of the light scanner 250a, such as the reflective surfaces 251-2 and 251-6, may have different inclination angles θ1 and θ2 relative to the central axis (z-axis), such as Figure 5A In addition, Figure 5B As shown, each of the reflective surfaces 251 of the light scanner 250 a may have a different tilt angle with respect to the central axis (z-axis).

[0079] The reflective surface 251 of the light scanner 250a can be formed using a material with high reflectivity. Suitable materials include high-reflectivity white resin, metal, and reflective paint. White resins can include white foamed PET and white polycarbonate. These materials can have a reflectivity of approximately 97% and exhibit minimal efficiency loss due to minimal light loss due to reflection. The metal can be at least one selected from the group consisting of high-reflectivity metals such as Ag, Al, Au, Cu, Pd, Pt, and Rd, and their alloys. The reflective surface 251 can be formed by vapor deposition. Alternatively, reflective paints with a reflectivity of approximately 80% to 90%, such as titanium oxide (TiO2), zinc oxide (ZnO), and calcium carbonate (CaCO3), can be used alone or in combination. This reflective paint can be applied by diluting a binder in a solvent and coating it on a material such as plastic. Application methods include spraying, rollers, and the like.

[0080] According to an embodiment, because the inclination angles of at least two of the reflective surfaces 251 of the light scanner 250a are different from each other, the travel path of the light reflected by the rotation of the light scanner 250a can be changed even if the light is incident along a constant incident direction. Light incident on a specific reflective surface 251 can be reflected by the specific reflective surface 251 according to the rotation of the light scanner 250a, so that the area within the scanning range 11 is scanned in a direction perpendicular to the central axis (z-axis) of the light scanner 250a.

[0081] According to an embodiment, since reflective surface 251 rotates as light scanner 250a rotates, light can be incident on reflective surface 251 at different tilt angles. Therefore, light scanner 250a can change the path of incident light along the central axis (z-axis) of light scanner 250a in response to changes in the tilt angle. Consequently, the reflected light can scan different areas within scanning range 11 that are parallel to the central axis (z-axis) of light scanner 250a.

[0082] The scanning range 11 of the light scanner 250a can be determined by the range of the tilt angle and the direction of the incident light from the light source. The spatial resolution of the light scanner 250a can be determined by the light driving cycle of the light source, the wavelength of the light, the scanning cycle of the light scanner 250a, and the number of reflective surfaces 251. The temporal resolution of the light scanner 250a can be determined by the number of lights, the scanning cycle of the light scanner 250a, etc.

[0083] At the same time, the first light source 210 can radiate first light L1 toward the light scanner 250a along a first incident direction, and the second light source 230 can radiate second light L2 toward the light scanner 250a along a second incident direction different from the first incident direction. For example, while the first light source 210 radiates the first light L1 toward the first reflective surface 251-1 of the light scanner 250a, the second light source 230 can radiate the second light L2 toward the seventh reflective surface 251-7 of the light scanner 250a, which is different from the first reflective surface 251-1. The travel path of the first light L1 reflected by the first reflective surface 251-1 and the travel path of the second light L2 reflected by the seventh reflective surface 251-7 can be different from each other. In other words, the first light L1 and the second light L2 can scan different areas within the scanning range 11 in the vertical directions S1 and S2.

[0084] Figure 6A 、 Figure 6B and Figure 6C is a reference diagram illustrating a scanning method performed by the light scanner 250a during one scanning cycle according to an embodiment. According to an embodiment, the light scanner 250a may divide a scanning range into a plurality of regions and scan the scanning range 11 in a vertical direction. According to an embodiment, the number of regions divided and scanned by the light scanner 250a may be determined by the number of reflective surfaces 251. Which region of the divided regions the light scanner 250a scans may be determined by the inclination angle of the reflective surface 251 of the light scanner 250a, the incident direction of light incident on the reflective surface 251, and the like.

[0085] For example, when the optical scanner 250a includes eight reflective surfaces 251 having different inclination angles, the optical scanner 250a can divide the scanning range 11 into eight areas and scan the eight areas. The inclination angles of the first to eighth reflective surfaces 251-1, ..., 251-8 can be set so that the first to eighth reflective surfaces 251-1, ..., 251-8 can scan the first to eighth areas 11-1, ..., 11-8, respectively. The inclination angles of the first to eighth reflective surfaces 251-1, ..., 251-8 can be preset so that the first to eighth reflective surfaces 251-1, ..., 251-8 can scan the first to eighth areas 11-1, ..., 11-8, respectively.

[0086] The first light source 210 may provide the first light L1 to the first reflective surface 251-1 of the light scanner 250a, and the second light source 230 may provide the second light L2 to the seventh reflective surface 251-7 of the light scanner 250a, so that the light scanner 250a can perform a scanning operation. The light scanner 250a may start scanning the first area 11-1 using the first light L1 and start scanning the seventh area 11-7 using the second light L2.

[0087] When the light scanner 250a rotates so that the first light L1 is provided to the second reflective surface 251-2 and the second light L2 is provided to the eighth reflective surface 251-8, the light scanner 250a can scan the second area 11-2 with the first light L1 and scan the eighth area 11-8 with the second light L2. When the light scanner 250a rotates during the 1 / 2 scanning period, as shown in FIG. Figure 6B As shown, the light scanner 250a may sequentially scan the first to fourth regions 11-1 to 11-4 using the first light L1, and may sequentially scan the seventh to third regions 11-7 to 11-3 using the second light L2.

[0088] According to an embodiment, when the optical scanner 250a rotates during one scanning cycle, as shown in FIG. Figure 6C As shown, the light scanner 250a can scan the entire scanning range 11 from the first area 11-1 to the eighth area 11-8 using the first light L1, and can scan the entire scanning range 11 from the seventh area 11-7 to the sixth area 11-6 using the second light L2. Therefore, even if only one light scanner 250a is provided, when a plurality of lights are provided, the light scanner 250a can scan the scanning range 11 a plurality of times during one scanning cycle.

[0089] exist Figure 4In the embodiment, optical scanner 250a scans the surrounding area through mechanical movement, but is not limited thereto. Optical scanner 250a may scan the surrounding area based on an electrical signal. For example, optical scanner 250 may include an optical phased array that modulates the phase of incident light to change the path of light. Optical scanner 250 may include an optical phased array comprising multiple channels that modulate the phase of incident light, and a signal inputter that applies a modulation signal to each of the multiple channels.

[0090] Figure 7 FIG is a diagram showing an optical scanner including an optical phased array OPA according to an embodiment. Figure 7 The optical phased array OPA may include a plurality of channels CH. A phase change value for changing the phase of incident light may be set in each of the plurality of channels CH, and thus the direction in which the incident light is turned and emitted may be adjusted.

[0091] Each of the multiple channels CH of the optical phased array OPA may include a meta-device with a sub-wavelength shape size, through which the phase change value relative to the incident light can be electrically adjusted.

[0092] Alternatively, the optical phased array (OPA) can be a silicon photonics-based optical waveguide that diverges the path of incident light into multiple paths and directs these multiple paths to corresponding output terminals, i.e., multiple channels (CH). The optical waveguide can include a phase retarder disposed in each of the diverging multiple paths, and the direction in which the incident light is diverted and emitted can be adjusted by adjusting the length of each path and / or the phase delay in the phase retarder of each path.

[0093] An optical phased array (OPA) can change the path of light in a direction determined by the combination of phase change values ​​that appear in each channel relative to the incident light. Based on the combination of phase change values, the direction in which the incident light is diverted and emitted can be adjusted sequentially.

[0094] Therefore, even when first light L1 and second light L2 having different phases are incident on the optical phased array OPA and phase modulation occurs due to the same modulation signal for the first and second lights L1 and L2, since the phases of the first and second lights L1 and L2 are different from each other at the time of incidence, the first and second lights L1 and L2 can be emitted to the surrounding area via different travel paths. Alternatively, multiple lights having different incident directions can be incident on the optical phased array OPA, so that the multiple lights can be emitted to the surrounding area via different travel paths.

[0095] Figure 8 is a diagram illustrating an example of a light receiver 120A according to the embodiment.

[0096] According to an embodiment, the optical receiver 120A may include a light detector 310 that converts light reflected by a target point in the scanning range 11 of the surrounding area, corresponding to the first light L1 and the second light L2 that scan the surrounding area, into an electrical signal, for example, a current. Among the first light L1, the first light reflected or scattered by the target point (that is, the first light including information about the target point) may be referred to as the first target light L1. 11 Among the second light L2, the second light reflected or scattered by the target point (ie, the second light including information about the target point) may be referred to as the second target light L2. 22 The light detector 310 can detect the first target light L 11 The first target signal is output as an electrical signal, and the second target light L can be detected 22 The second target signal is output as an electrical signal.

[0097] The light detector 310 may be arranged in a plurality of pixels in an array form. The plurality of pixels may be arranged in a matrix form. It may be determined whether the detected electric signal is consistent with the first target light L1 based on the position of the pixel detected in the pixel, the detected electric signal, the scanning information of the light scanner 250, and the optical characteristics of the first light L1 and the second light L2. 11 The corresponding first target signal is still the same as the second target light L 22 The corresponding second target signal.

[0098] Each of the pixels may be a light-receiving device that operates with a bias voltage applied. For example, the light detector 310 may include an avalanche photodiode (APD) or a single-photon avalanche diode (SPAD). The light detector 310 may have various specific circuit configurations, such as an analog front end (AFE) or a time-to-digital counter (TDC). Depending on the specific circuit configuration, the light detector 310 includes a light-receiving device between the APD and the SPAD. Such specific circuit configurations are conventional, and therefore a detailed description thereof will be omitted.

[0099] The optical receiver 120A may further include a current-to-voltage conversion circuit that converts the output current into a voltage, an amplifier that amplifies the voltage, a lens that collects light reflected or scattered at a target point, and a filter that filters electrical signals of a specific frequency, such as a high-pass filter.

[0100] The light receiver 120A may include a light detector 310 including a plurality of pixels 312 , and a circuit 330 for measuring a time of flight (TOF) of light detected in each of the plurality of pixels 312 .

[0101] According to an embodiment, the circuit 330 for measuring TOF may include: a plurality of current-voltage conversion circuits 331, which convert the current output from each of the plurality of pixels 312 into a voltage; a plurality of amplifiers 333, which amplify the voltage converted by each of the plurality of current-voltage conversion circuits 331; a plurality of peak detectors 335, which detect peak values ​​from the signals amplified by the plurality of amplifiers 333; and a plurality of time counters 337, which determine TOF using the peak values.

[0102] The plurality of current-voltage conversion circuits 331 may convert a current signal output from each of the plurality of pixels 312 into a voltage signal.

[0103] The plurality of amplifiers 333 may amplify the voltage signal converted by each of the plurality of current-voltage conversion circuits 331 .

[0104] Multiple peak detectors 335 can detect peak values ​​from the voltage signal amplified by each of the multiple amplifiers 333. For example, multiple peak detectors 335 can detect peak values ​​by detecting rising and falling edges of the electrical signal. Alternatively, multiple peak detectors 335 can use a constant fraction discriminator (CFD) method to detect peak values. Multiple peak detectors 335 can also include a comparator and output the detected peak values ​​as pulse signals.

[0105] Multiple time counters 337 can measure the time of flight of light detected by each of the multiple pixels 312. When a pulse signal output from each of the multiple peak detectors 335 is input, each of the multiple time counters 337 can count how many cycles of the clock signal are generated from the light radiation time of the light source, and can measure the time of flight of the light. In addition, each of the multiple time counters 337 can store information related to each measured time of flight of light in a register. Each of the multiple time counters 337 can be implemented as a time-to-digital converter (TDC).

[0106] The measurement result of the time counter 337 may be sent to the processor 130. The processor 130 may use the measurement result to acquire a frame about the scanning range 11. The result output from the optical receiver 120A may be referred to as scanning data, as data including distance information of each target point within the scanning range 11. 11 The corresponding data may be referred to as first scanning data and is related to the second target light L 22 The corresponding data may be referred to as second scan data.

[0107] The processor 130 may use the first scan data and the second scan data output from the light receiver 120A to acquire a frame including depth information about the scanning range 11. The frame may be a combination of the first scan data and the second scan data, may be corrected data of the first scan data and the second scan data, or may be 3D shape modeling data based on the first scan data and the second scan data.

[0108] The processor 130 can transmit the above frames to another unit external to the processor. For example, such frame information can be transmitted to the processor of an autonomous driving device (e.g., an autonomous vehicle, a drone, etc.) that employs the LiDAR device 100. Furthermore, such frame information can be utilized in smartphones, mobile phones, personal digital assistants (PDAs), laptop computers, PCs, various wearable devices, and other mobile or non-mobile computing devices. Alternatively, the processor 130 according to an embodiment can be included in another device capable of communicating with the optical receiver 120A.

[0109] According to an embodiment, when acquiring a frame from the first scanning data and the second scanning data, the processor 130 generates a signal when the first light L1 or the first target light L 11 The first scanning data corresponding to the second light L2 or the second target light L 22 The corresponding second scanning data are distinguished.

[0110] Figure 9 is a diagram illustrating a method of acquiring a frame according to an embodiment.

[0111] Processor 130 may distinguish whether the data output from optical receiver 120 is first scan data or second scan data (S510). Processor 130 may determine whether the output signal corresponds to first light L1 or second light L2 based on the following: the location of the pixel of optical detector 310 that detects first light L1 or second light L2, the optical characteristics of first light L1 and second light L2, the incident direction of first light L1 and second light L2, scanning information of optical scanner 250 (e.g., the tilt angle of reflective surface 251, the scanning period, the number of reflective surfaces 251, etc.), driving information of first light L1 and second light L2, etc. For example, when the duty cycles of first light L1 and second light L2 are different from each other, processor 130 may use the duty cycle of the detected electrical signal to determine whether the detected electrical signal corresponds to first light L1 or second light L2. Alternatively, when the first light L1 and the second light L2 are alternately provided to the light scanner 250 , the processor 130 may determine that the detected electric signals are alternately received corresponding to the alternately provided first light L1 and second light L2 .

[0112] The processor 130 may acquire frames from the first scanning data and the second scanning data during one scanning cycle of the light scanner 250 (S520). The processor 130 may acquire a first initial frame for the first light L1 from the first scanning data during one scanning cycle. The first initial frame may include distance information related to target points within the scanning range 11 during one scanning cycle. Similarly, the processor 130 may acquire a second initial frame for the second light L2 from the second scanning data during one scanning cycle. The second initial frame may include distance information related to target points within the scanning range 11 during one scanning cycle.

[0113] The processor 130 may acquire a frame using the first initial frame and the second initial frame. The processor 130 may acquire a frame by applying a correlation between the first initial frame and the second initial frame. For example, the processor 130 may apply a cross-correlation function to each corresponding target point of the first initial frame and the second initial frame, and when the resulting value is equal to or greater than a reference value, determine that the target point is a valid target point, and when the resulting value is less than the reference value, determine that the target point is an invalid target point. Alternatively, when the difference in depth information of each corresponding target point between the first initial frame and the second initial frame is less than a reference value, the processor 130 may determine that the target point is a valid target point, and when the difference is equal to or greater than the reference value, determine that the target point is an invalid target point. Alternatively, when a target point exists in one of the first initial frame and the second initial frame but does not exist in the other, the processor 130 may determine that the target point is an invalid target point.

[0114] In addition, the processor 130 may acquire a frame including depth information of valid target points. When the valid target points are the same point within the scanning range 11, the processor 130 may acquire a frame including an average of the depth information of the valid target points. The target points of the first initial frame and the second initial frame may not match. When the target points of the first initial frame and the second initial frame do not match, the processor 130 may acquire a frame including depth information of each valid target point.

[0115] Figure 10 is a reference diagram illustrating a method of acquiring a frame according to an embodiment. Figure 10 As shown in (i), the processor 130 can obtain the first initial frame PF1 from the first scanning data, and as shown in Figure 10 As shown in (ii), the processor 130 may obtain a second initial frame PF2 from the second scanning data.

[0116] Meanwhile, an arbitrary target point 610 is included in the first initial frame PF1, but may not be included in the second initial frame PF2. When correlation is applied to the first initial frame PF1 and the second initial frame PF2, the target point 610 may be determined to be an invalid target point. The target point 610 may be provided by the LiDAR device 100 and may have the same optical information as the first light L1, but the processor 130 may determine that the target point 610 is noise by applying correlation to the first initial frame PF1 and the second initial frame PF2.

[0117] Therefore, if Figure 10 As shown in (iii), the processor 130 may obtain a frame F that does not include the invalid target point 610. As described above, for example, the processor 130 may obtain a frame F that includes a valid target point EP, where the valid target point EP is an average value of depth information of corresponding target points of the first initial frame PF1 and the second initial frame PF2. Figure 10 (iii) shows a frame when the corresponding target points P1 and P2 of the first initial frame PF1 and the second initial frame PF2 match, but the present disclosure is not limited thereto. The corresponding target points P1 and P2 of the first initial frame PF1 and the second initial frame PF2 may not match.

[0118] Figure 11 FIG is a reference diagram illustrating a method for acquiring a frame according to another embodiment. Figure 11 (i) and Figure 11 As shown in (ii), the first initial frame PF1 and the second initial frame PF2 may not match the target points P1 and P2, respectively. The processor 130 may determine the valid target point EP by applying the correlation to the first initial frame PF1 and the second initial frame PF2. Figure 11 As shown in (iii), the processor 130 may acquire a frame F including depth information of the effective target point EP. The acquired frame F may have a higher spatial resolution than the first initial frame PF1 and the second initial frame PF2.

[0119] The processor 130 obtains the frame F by distinguishing the first scan data from the second scan data, but is not limited thereto. The processor 130 may obtain the frame F without distinguishing the first scan data from the second scan data. For example, the processor 130 may obtain the frame F using a scan cycle.

[0120] Figure 12 is a flowchart illustrating a method of acquiring a frame according to another embodiment. Figure 13 It shows Figure 12 Reference diagram of the method of acquiring frames.

[0121] The processor 130 may receive third scanning data from the optical receiver 120 during the ½ scanning period to obtain a third initial frame (S710). The third scanning data may include first scanning data based on the first light L1 and second scanning data based on the second light L2. For example, the optical scanner 250 may vertically divide the scanning range 11 into two equal parts, scan the upper area of ​​the scanning range 11 using the first light L1 during the ½ scanning period, and scan the lower area of ​​the scanning range 11 using the second light L2. The optical receiver 120 may detect the first target light L1 reflected in the scanning range 11. 11 and the second target light L 22 , and accordingly outputs the first scanning data and the second scanning data including the depth information.

[0122] The processor 130 may determine the position of the target point of the first scan data and the second scan data by considering the position of the pixel where the first light L1 or the second light L2 is detected in the light detector 310, the incident directions of the first light L1 and the second light L2, the scanning information of the light scanner 250 (e.g., the tilt angle of the reflective surface 251, the scanning period, the number of reflective surfaces 251, etc.). Figure 13 As shown in (i), the processor 130 may acquire a third initial frame PF3. For example, the processor 130 may acquire a third initial frame PF3 including a first region based on the first scanning data and a second region based on the second scanning data.

[0123] In addition, the processor 130 may receive fourth scanning data from the light receiver 120 during the next 1 / 2 scanning period. The fourth scanning data may include first scanning data based on the first light L1 and second scanning data based on the second light L2. Figure 13 As shown in (ii), the processor 130 may acquire a fourth initial frame PF4 including a first region based on the second scanning data and a second region based on the first scanning data.

[0124] In addition, the processor 130 may acquire a frame F using the third initial frame PF3 and the fourth initial frame PF4. For example, the processor 130 may acquire the frame F by applying correlation to the third initial frame PF3 and the fourth initial frame PF4. Figure 13 (iii) shows frame F acquired from the third initial frame PF3 and the fourth initial frame PF4. As described above, when the light scanner 250 scans an area where the first light L1 and the second light L2 do not overlap during a ½ scanning period, the processor 130 can acquire frame F without distinguishing between the first light L1 and the second light L2. Acquiring frame F as described above can not only improve crosstalk but also increase temporal resolution.

[0125] Figure 14is a reference diagram illustrating a method for acquiring frames with increased temporal resolution according to an embodiment. When the light scanner 250 scans an area where the first light L1 and the second light L2 do not overlap with each other during a 1 / 2 scanning period T / 2, the processor 130 can acquire initial frames PF3, PF4, and PF5 at intervals of 1 / 2 scanning period T / 2. Therefore, at one scanning time after the start of scanning, the processor 130 can acquire the first frame from the two initial frames PF3 and PF4. In addition, the processor 130 can acquire another initial frame PF5 during the next 1 / 2 scanning period T / 2, thereby acquiring the second frame from the two initial frames PF4 and PF5. That is, the processor 130 can acquire one frame every 1 / 2 scanning period, and therefore the time used to acquire a frame is shorter than the scanning period. Therefore, the LiDAR device according to the embodiment can increase the temporal resolution.

[0126] The temporal resolution may be proportional to the amount of light provided. Figure 15 This is a reference diagram illustrating a method for acquiring frames with increased temporal resolution according to another embodiment. When the light scanner 250 scans an area where the first to third lights do not overlap during a 1 / 3 scanning period (T / 3), the processor 130 can acquire initial frames at intervals of the 1 / 3 scanning period (T / 3). Therefore, the processor 130 can acquire the first frame one scanning time after the start of scanning, but can acquire the second frame at the next 1 / 3 scanning period. Thus, the processor 130 can acquire frames at intervals of the 1 / 3 scanning period (T / 3), thereby increasing temporal resolution.

[0127] According to certain embodiments, the apparatus for controlling the LiDAR device 100 may include a processor 130, a memory for storing and executing program data, a permanent storage unit such as a disk drive, a communication port for handling communications with external devices, and a user interface device (including a touch panel, keys, buttons, etc.) for receiving input information and outputting output information. For example, when software modules or algorithms are involved, these software modules may be stored as computer-readable code executable on the processor 130 or as program instructions in a computer-readable recording medium. Examples of computer-readable recording media include magnetic storage media (e.g., read-only memory (ROM), random access memory (RAM), floppy disks, hard disks, etc.) and optical recording media (e.g., CD-ROMs or digital versatile disks (DVDs)). The computer-readable recording medium may also be distributed among computer systems coupled to a network, allowing for distributed storage and execution of the computer-readable code. The medium can be read by a computer, stored in memory, and executed by the processor 130.

[0128] Certain embodiments may be described in terms of functional block components and various processing steps. Such functional blocks may be implemented using any number of hardware and / or software components configured to perform the specified functions. For example, certain embodiments may employ various integrated circuit (IC) components, such as memory elements, processing elements, logic elements, lookup tables, etc., which may perform various functions under the control of one or more microprocessors or other control devices. Similarly, when software programming or software elements are used to implement components, certain embodiments may be implemented using any programming or scripting language (such as C, C++, Java, assembly language, etc.) and various algorithms, wherein the various algorithms utilize any combination of data structures, objects, procedures, routines, or other programming elements. Functional blocks may be implemented using algorithms executed on one or more processors 130. Furthermore, certain embodiments described herein may employ any number of conventional techniques for electronic configuration, signal processing and / or control, data processing, etc. The terms "mechanism," "element," "means," and "configuration" are used broadly and are not limited to mechanical or physical embodiments. These terms may include software routines in conjunction with processors 130, etc.

[0129] The specific implementations shown and described herein are illustrative examples and are not intended to limit the scope of the present disclosure in any other way. For the sake of brevity, other functional aspects of conventional electronic devices, control systems, software development, and systems may not be described in detail. In addition, the connecting lines or connectors shown in the various figures presented are intended to represent exemplary functional relationships and / or physical or logical couplings between the various elements. It should be noted that many alternative or additional functional relationships, physical connections, or logical connections may exist in actual devices.

[0130] It should be understood that the specific embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each embodiment should generally be considered as applicable to other similar features or aspects in other embodiments. Although one or more embodiments have been described with reference to the accompanying drawings, it will be understood by those skilled in the art that various changes in form and details may be made without departing from the spirit and scope of the appended claims.

Claims

1. A light detection and ranging LiDAR device, comprising: a light scanner configured to periodically scan an area in a surrounding area by sequentially changing a travel path of incident light; a first light source configured to provide first light to the light scanner in a first incident direction; a second light source configured to provide second light to the light scanner in a second incident direction different from the first incident direction; a light receiver configured to detect third light reflected in the region of the surrounding area from the first light and fourth light reflected in the region of the surrounding area from the second light; as well as a processor configured to acquire a frame including depth information of the area of ​​the surrounding area by using a detection result from the light receiver, wherein the light scanner is further configured to scan the area in the surrounding area multiple times using the first light and the second light during one scanning cycle of the light scanner, wherein the light scanner scans the entire scanning range of the area in the surrounding area using the first light during the one scanning cycle, and the light scanner scans the entire scanning range of the area in the surrounding area using the second light during the one scanning cycle, and Wherein, the processor is further configured to: obtain a first initial frame including depth information of the area of ​​the surrounding area corresponding to the first light during the one scanning cycle and a second initial frame including depth information of the area of ​​the surrounding area corresponding to the second light during the one scanning cycle from the detection results from the light receiver, and obtain the frame by applying correlation to the first initial frame and the second initial frame.

2. The LiDAR device according to claim 1, in, The first light source and the second light source are configured to intermittently provide the first light and the second light to the light scanner.

3. The LiDAR device according to claim 2, in, The first light source and the second light source are configured to simultaneously or alternately provide the first light and the second light to the light scanner.

4. The LiDAR device according to claim 1, in, The light scanner is further configured to sequentially change a travel path of the incident light by rotating the light scanner relative to a central axis of the light scanner.

5. The LiDAR device according to claim 4, in, A scanning period of the optical scanner is less than or equal to a rotation period of the optical scanner.

6. The LiDAR device according to claim 1, in, The light scanner includes a plurality of reflective surfaces, each of which is parallel to or inclined with respect to a central axis of the light scanner.

7. The LiDAR device according to claim 6, in, A first reflective surface among the plurality of reflective surfaces has a first inclination angle, and a second reflective surface among the plurality of reflective surfaces has a second inclination angle different from the first inclination angle.

8. The LiDAR device according to claim 6, in, Adjacent reflecting surfaces among the plurality of reflecting surfaces have different inclination angles.

9. The LiDAR device according to claim 6, in, While the first light source is configured to provide the first light to a first reflective surface among the plurality of reflective surfaces, the second light source is configured to emit the second light to a second reflective surface different from the first reflective surface among the plurality of reflective surfaces.

10. The LiDAR device according to claim 9, in, The first reflective surface scans a first sub-region of the region in the surrounding region by sequentially reflecting the first light in different directions, and The second reflective surface scans a second sub-region of the area in the surrounding area that is different from the first sub-region by sequentially reflecting the second light in different directions.

11. The LiDAR device according to claim 10, in, The first sub-region and the second sub-region do not overlap with each other.

12. The LiDAR device according to claim 10, in, The first sub-area and the second sub-area are arranged parallel to a rotation axis of the light scanner.

13. The LiDAR device according to claim 1, in, The processor is further configured to: acquiring a third initial frame including depth information of the area in the surrounding area by using a detection result from the light receiver during a first time, acquiring a fourth initial frame including depth information of the area in the surrounding area by using a detection result from the light receiver during a second time after the first time, and The frame is acquired using the third initial frame and the fourth initial frame.

14. The LiDAR device according to claim 13, in, Each of the third initial frame and the fourth initial frame includes depth information corresponding to both the first light and the second light.

15. The LiDAR device according to claim 13, in, The first time and the second time are equal to 1 / 2 of the scanning period of the optical scanner.

16. A method of operating a light detection and ranging (LiDAR) device, the method comprising: providing the first light and the second light to the optical scanner; scanning an area in a surrounding area multiple times with the first light and the second light during one scanning cycle of the light scanner by sequentially changing the travel paths of the first light and the second light by the light scanner; detecting third light reflected in the region of the surrounding area from the first light and fourth light reflected in the region of the surrounding area from the second light; as well as acquiring a frame including depth information of the area of ​​the surrounding area by using a result of the detection, wherein the scanning comprises: scanning the entire scanning range of the area in the surrounding area by the light scanner using the first light during the one scanning cycle, and scanning the entire scanning range of the area in the surrounding area by the light scanner using the second light during the one scanning cycle, and Wherein, acquiring the frame includes: acquiring a first initial frame including depth information of the area of ​​the surrounding area corresponding to the first light during the one scanning cycle and a second initial frame including depth information of the area of ​​the surrounding area corresponding to the second light during the one scanning cycle in the results of the detection, and acquiring the frame by applying correlation to the first initial frame and the second initial frame.

17. The method according to claim 16, in, The scanning includes scanning a first sub-region of the region in the surrounding region using the first light and scanning a second sub-region of the region in the surrounding region that does not overlap with the first sub-region using the second light.

18. The method according to claim 17, in, The scanning further includes: scanning the second sub-area using the first light, and simultaneously scanning the first sub-area using the second light.

19. The method according to claim 16, in, The providing includes providing the first light to the light scanner in a first incident direction, and providing the second light to the light scanner in a second incident direction different from the first incident direction.

20. The method according to claim 16, in, The providing includes simultaneously or alternately providing the first light and the second light to the light scanner.

21. An apparatus for controlling a light detection and ranging LiDAR device, comprising: a memory configured to store one or more instructions; as well as A processor configured to execute the one or more instructions to perform the method according to any one of claims 16 to 20.

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