Light detection and ranging device and driving method thereof

Abstract

A light detection and ranging (LiDAR) device is provided, comprising: a scanning optical system including a plurality of light sources and a beam steering device, the scanning optical system being configured to scan an object using a plurality of illumination light beams projected toward the object at a plurality of illumination angles respectively from the plurality of light sources; a light detector including a plurality of pixel areas, the plurality of pixel areas being configured to respectively detect the plurality of illumination light beams projected toward the object at the plurality of illumination angles and reflected from the object; and a processor being configured to control the scanning optical system and the light detector, and to obtain information about the object based on the plurality of illumination light beams detected by the light detector.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the priority of Korean Patent Application No. 10-2018-0153716 filed in the Korean Intellectual Property Office on December 3, 2018, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] Example embodiments of the present disclosure relate to a light detection and ranging (LiDAR) device and a method of driving the LiDAR device. Background Art

[0004] Light detection and ranging (LiDAR) systems are used in a variety of fields such as aerospace, geology, 3D mapping, automotive, robotics, and drones.

[0005] The LiDAR system uses a method of measuring the time required for light to travel back and forth (hereinafter referred to as the time of flight (TOF) method) as a basic operating principle. That is, after emitting light toward an object, the sensor receives the light reflected from the object and measures the TOF of the light using a high-speed circuit. The distance to the object can be calculated using the TOF. The depth image of the object can be processed by using the calculated distance to the object's position.

[0006] However, in this approach, the resolution of the image that can be obtained within a given frame time is limited due to the speed of light being limited. Summary of the invention

[0007] One or more example embodiments provide a LiDAR device having improved image resolution and a method of driving the LiDAR device.

[0008] Additional aspects will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of example embodiments.

[0009] According to one aspect of an example embodiment, a light detection and ranging (LiDAR) device is provided, comprising: a scanning optical system including a plurality of light sources and a beam steering device, the scanning optical system being configured to scan an object using a plurality of illumination light beams projected toward the object at a plurality of illumination angles, respectively, from the plurality of light sources; a light detector including a plurality of pixel areas, the plurality of pixel areas being configured to respectively detect the plurality of illumination light beams projected toward the object at the plurality of illumination angles and reflected from the object; and a processor being configured to control the scanning optical system and the light detector, and to obtain information about the object based on the plurality of illumination light beams detected by the light detector.

[0010] Angles between the plurality of illumination light beams projected from the plurality of light sources toward the object may be equal to or greater than an angular resolution of the light detector.

[0011] A plurality of pixel areas may be provided in the photodetector so that the plurality of illumination light beams projected onto the object at the plurality of illumination angles and reflected from the object are incident on different pixel areas among the plurality of pixel areas.

[0012] An angle between the plurality of illumination light beams projected from the plurality of light sources toward the object may be equal to or greater than 1°.

[0013] The plurality of light sources may be configured to emit the plurality of illumination light beams towards an object simultaneously or within a predetermined time period.

[0014] The predetermined time period may be 1 μs or shorter.

[0015] The processor may also be configured to determine a distance to the object based on the illumination angle and a flight time of the plurality of illumination light beams reflected from the object, and perform data processing to analyze a position of the object and a shape of the object.

[0016] The processor may be further configured to control the scanning optical system to scan the object by dividing the area of ​​the object into a plurality of areas corresponding to the number of the plurality of light sources.

[0017] The processor may be further configured to control the scanning optical system to select a number of the plurality of light sources and scan the object based on the selected light sources.

[0018] The processor may be further configured to set the number of light sources to be selected based on a reference time period for processing one image frame of the object and an image resolution.

[0019] The plurality of pixel regions may include a plurality of light detecting elements, respectively, and each of the plurality of light detecting elements may include at least one of an avalanche photodiode and a single photon avalanche diode.

[0020] The light detector may include: a plurality of time counters configured to respectively measure flight times of the plurality of illumination light beams detected by the plurality of pixel regions.

[0021] The photodetector may also include: a plurality of current-to-voltage conversion circuits configured to convert a plurality of currents respectively output from the plurality of pixel regions into a plurality of voltages; a plurality of amplifiers configured to amplify the plurality of voltages respectively output from the plurality of current-to-voltage conversion circuits; and a plurality of peak detectors configured to respectively detect a plurality of peaks in the plurality of signals amplified by the plurality of amplifiers.

[0022] The beam steering device may include a scanning mirror configured to adjust an illumination angle of each of the plurality of illumination beams projected from the plurality of light sources by mechanical rotation.

[0023] The beam steering device may include an optical phased array configured to adjust an illumination angle of each of the plurality of illumination beams projected from the plurality of light sources by phase control.

[0024] According to an aspect of an example embodiment, there is provided a method for driving a light detection and ranging (LiDAR) device, the method comprising: projecting a plurality of illumination light beams toward an object at a plurality of illumination angles using a plurality of light sources, respectively; detecting the plurality of illumination light beams projected toward the object at the plurality of illumination angles and reflected from the object, respectively; and obtaining information about a position and a shape of the object based on the detection.

[0025] Angles between the plurality of illumination light beams projected from the plurality of light sources toward the object may be equal to or greater than an angular resolution of the light detector.

[0026] The plurality of illumination light beams may be projected toward the object by the plurality of light sources simultaneously or within a predetermined time period.

[0027] The method may further include setting a number of light sources among the plurality of light sources to be used to project the plurality of illumination light beams toward the object.

[0028] The number of light sources to be used may be set based on a reference time period for processing one image frame of an object and an image resolution.

[0029] The plurality of illumination light beams projected onto the object at the plurality of illumination angles and reflected from the object may be detected by different pixel areas among the plurality of pixel areas.

[0030] According to an aspect of another example embodiment, a light detection and ranging (LiDAR) device is provided, comprising: a scanning optical system including a plurality of light sources and a beam steering device, and configured to scan an object, the plurality of light sources being configured to emit a plurality of illumination beams respectively and substantially simultaneously toward the beam steering device, the beam steering device being configured to steer the plurality of illumination beams toward the object at a plurality of illumination angles, respectively, wherein substantially simultaneously is simultaneously or in 1 μs or less; a two-dimensional light detector array having a plurality of pixel areas, each of the plurality of pixel areas being configured to respectively detect a different light beam among the plurality of illumination beams emitted substantially simultaneously and projected toward and reflected from the object; and a processor configured to control the scanning optical system and the light detector, and obtain information about the object based on the plurality of illumination beams detected by the light detector.

[0031] An image resolution of an image of the object may correspond to the number of the plurality of light sources.

[0032] The processor may be further configured to control the scanning optical system to select a number of the plurality of light sources and scan the object based on the selected light sources.

[0033] The processor may be further configured to set the number of light sources to be selected based on a reference time period for processing one image frame of the object and an image resolution. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The above and / or other aspects will become clear and more readily understood from the following description of example embodiments in conjunction with the accompanying drawings, in which:

[0035] Figure 1 is a flowchart schematically illustrating a method of driving a light detection and ranging (LiDAR) device according to an example embodiment;

[0036] Figure 2 is a block diagram schematically illustrating a LiDAR device according to an example embodiment;

[0037] Figure 3 It is shown Figure 2 A view of an example arrangement and operation of the scanning optical system and light detector of a LiDAR device shown in;

[0038] Figure 4A and Figure 4B It is shown Figure 2 An example of a beam steering device for a LiDAR device and a view of the principle of point scanning using the example beam steering device shown in;

[0039] Figure 5 It is shown Figure 2 A block diagram of an example structure of a processor of a LiDAR device as shown in;

[0040] Figure 6 It is shown by Figure 5 A diagram of an example of a processor dividing an object region as shown in FIG.

[0041] Figure 7 It is shown Figure 2 A view of an example circuit configuration for a photodetector of a LiDAR device shown in;

[0042] Figure 8 is a flowchart schematically illustrating a method of driving a LiDAR device according to an example embodiment;

[0043] Fig. 9 is a block diagram schematically illustrating a LiDAR device according to an example embodiment; and

[0044] Fig.10 It is shown Fig. 9 00140 00141 00141 00142 00143 00144 00145 00146 00147 00148 00149 ...9 00149 00149 00149 DETAILED DESCRIPTION

[0045] Reference will now be made in detail to the example embodiments shown in the accompanying drawings, wherein throughout the text, the same reference numerals refer to the same elements, and for clarity, the size of the elements may be exaggerated. In this regard, the example embodiments may have different forms and should not be construed as being limited to the description set forth herein. Therefore, the example embodiments are described below only by reference to the accompanying drawings to explain various aspects. As used herein, the term "and / or" includes any and all combinations of one or more of the related listed items. Statements such as "at least one of ......" modify the entire element list when after the element list, rather than modifying the individual elements in the list. For example, the statement "at least one of a, b, and c" should be understood to include only a, only b, only c, both a and b, both a and c, both b and c, or all of a, b, and c.

[0046] In the following description, when an element is referred to as being 'on' or "over" another element, it may be directly on the other element while being in contact with the other element, or may be on the other element without contacting the other element.

[0047] It will also be understood that the terms “comprises” and / or “comprising” as used herein specify the presence of described features or elements, but do not preclude the presence or addition of one or more other features or elements.

[0048] An element referred to with the definite article or demonstrative pronoun may be construed as referring to one or more elements even if it is in the singular.

[0049] Unless explicitly described or described to the contrary in terms of order, the operations of the method may be performed in an appropriate order. That is, the operations are not limited to the order in which the operations are described. In the present disclosure, examples or exemplary terms (e.g., "such as" and "etc.") are used for descriptive purposes and are not intended to limit the scope of the present disclosure unless limited by the claims.

[0050] Terms such as "unit" or "module" are used to indicate a unit having at least one function or operation, and are implemented by hardware, software, or a combination of hardware and software.

[0051] Figure 1 is a flowchart schematically illustrating a method of driving a light detection and ranging (LiDAR) device according to example embodiments.

[0052] The method of driving the LiDAR device includes operation S100, in which a plurality of light sources project light toward an object at different illumination angles, and operation S200, in which the light projected onto the object at different illumination angles and reflected from the object is detected, respectively. In addition, the method of driving the LiDAR device includes operation S300, in which information about the position and shape of the object is obtained using the detected light.

[0053] In the operation S100 of projecting light, light is projected from a plurality of light sources toward an object at different illumination angles. Therefore, when detecting light reflected from an object, light can be separated according to a plurality of light sources. To this end, the difference between the illumination angles of light emitted from a plurality of light sources toward an object can be set to be greater than the angular resolution of the light detector. For example, the difference between the illumination angles can be about 1° or greater. It may not be required that a plurality of light sources emit light simultaneously. For example, a plurality of light sources may emit light toward an object with a time difference equal to or less than a specific value (e.g., about 1 μs).

[0054] The method of driving a LiDAR device of an example embodiment can obtain information about an object at an image resolution equal to or greater than a specific value within a given frame time, which is a reference time period given for forming one image frame of the object. A LiDAR device to which the method is applicable will now be described.

[0055] Figure 2 is a block diagram schematically illustrating a configuration of a LiDAR apparatus 1000 according to an example embodiment, Figure 3 It is shown Figure 2 2 is a diagram of an example arrangement and operation of the scanning optical system 100 and the light detector 200 of the LiDAR device 1000 shown in FIG.

[0056] refer to Figure 2 The LiDAR device 1000 includes: a scanning optical system 100, configured to scan an object OBJ with light; a light detector 200, configured to detect light projected from the scanning optical system 100 toward the object OBJ and reflected from the object OBJ; and a processor 300, configured to control the scanning optical system 100 and the light detector 200.

[0057] The scanning optical system 100 includes a light source unit 110 and a beam steering device 180, wherein the light source unit 110 includes a plurality of light sources. The light source unit 110 and the beam steering device 180 can be arranged and operated so that the object OBJ can be scanned using light projected toward the object OBJ at different irradiation angles from the plurality of light sources through the beam steering device 180.

[0058] The multiple light sources of the light source unit 110 are configured to emit light for analyzing the position and shape of the object OBJ. The light source unit 110 can generate and project light with a predetermined wavelength. For example, the light source unit 110 can emit light of a band (e.g., an infrared band) for analyzing the position and shape of the object OBJ. When using light in the infrared band, the light emitted by the light source unit 110 can be prevented from mixing with natural light in a visible band such as sunlight. However, the light source unit 110 is not limited to emitting light in the infrared band. That is, the light source unit 110 can emit light of various bands. Examples of the multiple light sources of the light source unit 110 can include 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). The light source unit 110 can generate and project light of different bands. The light source unit 110 can generate and project pulsed light or continuous light.

[0059] The plurality of light sources of the light source unit 110 may emit light toward the object OBJ under the control of the processor 300. For example, the processor 300 may set a light emission direction or angle of each of the plurality of light sources, and may control the light source unit 110 so that the plurality of light sources emit light according to the light emission direction or angle set by the processor 300.

[0060] The beam steering device 180 directs the light emitted from the light source unit 110 toward the object OBJ in a manner of adjusting the directing direction in a time sequence. Therefore, the object OBJ can be completely scanned with the point light emitted from the light source unit 110. A scanning mirror or an optical phased array can be used as the beam steering device 180.

[0061] The light detector 200 may include a plurality of pixel regions to detect light reflected from the object OBJ according to positions. Figure 2 As shown, the light detector 200 may include a detector array 220 divided into a plurality of pixels PX1, PX2, ..., PXm. Light detection elements 222 may be placed in the pixels PX1, PX2, ..., PXm, respectively. That is, the light detection elements 222 may form pixels PX1, PX2, ..., PXm that are distinguishable in position in the detector array 220, and the pixels PX1, PX2, ..., PXm may respectively detect light reflected from the object OBJ according to the light emission angle of the light source unit 110.

[0062] The detector array 220 is shown to include m light detecting elements 222 arranged in a one-dimensional manner, but this is only an example. For example, the light detecting elements 222 may be arranged in a two-dimensional manner.

[0063] The pixels PX1, PX2, ..., PXm of the light detector 200 are provided as basic units for respectively detecting light projected from the scanning optical system 100 to the object OBJ at different illumination angles and reflected from the object OBJ. Although the pixels PX1, PX2, ..., PXm are described as including light detecting elements 222, respectively, this is a non-limiting example. The light detector 200 may be implemented as a single detector rather than an array of light detecting elements 222. In this case, different areas of the detector may be used as pixels for separating the detected light according to positions.

[0064] The light detector 200 may further include a circuit unit 240 to measure a time of flight (TOF) of light detected by each light detecting element 222. In addition, the light detector 200 may include an optical element for collecting light reflected from the object OBJ in predetermined pixels.

[0065] The light detecting element 222 may be a sensor capable of sensing light, such as a light receiving element configured to generate an electrical signal in response to light energy. The type of light receiving element is not particularly limited. The LiDAR device 1000 of the example embodiment uses a point scanning method as described above, so the intensity of light incident on the light detecting element 222 may be relatively low compared to examples using different methods such as a flash method. For example, an avalanche photodiode (APD) or a single photon avalanche diode (SPAD) having high sensitivity may be used as the light detecting element 222. A circuit such as an analog front end (AFE) circuit or a time to digital converter (TDC) may be used, depending on whether the light detecting element 222 of the light detector 200 includes an APD or a SPAD.

[0066] The processor 300 may perform a signal processing process using the light detected by the light detector 200 to obtain information about the object OBJ. For example, the processor 300 may determine the distance from the light source unit 110 to the position of the object OBJ based on the irradiation angle of the light to the object OBJ and the TOF of the light reflected from the object OBJ, and may perform a data processing process to analyze the position and shape of the object OBJ.

[0067] The information analyzed by the processor 300, i.e., information about the shape and position of the object OBJ, can be sent to other units. For example, such information can be sent to a controller of an autonomous driving device (e.g., an unmanned vehicle or drone) that employs the LiDAR device 1000. In addition, such information can be used in a smart phone, a cellular phone, a personal digital assistant (PDA), a laptop, a personal computer (PC), a wearable device, other mobile devices, or a non-mobile computing device.

[0068] In addition, the processor 300 may control the overall operation of the LiDAR device 1000 including the scanning optical system 100 and the light detector 200. The processor 300 may divide the area of ​​the object OBJ into separated areas by considering the number of light sources provided in the light source unit 110, and may output a control signal to the beam steering device 180 to scan all separated areas of the object OBJ using the beam steering device 180.

[0069] In addition, the processor 300 may control the operations of the light source unit 110 and the light detector 200. For example, the processor 300 may perform a power control operation, an on / off control operation, a pulse wave (PW) or a continuous wave (CW) generation control operation for the light source unit 110. In addition, the processor 300 may apply a control signal to each light detection element 222 of the light detector 200.

[0070] The LiDAR device 1000 may further include a memory to store programs and other data for the operation of the processor 300 .

[0071] The LiDAR apparatus 1000 of the example embodiment may include a scanning optical system 100 configured to scan an object OBJ using point light through a point scanning method, and may scan an entire area of ​​the object OBJ using a plurality of light sources of the scanning optical system 100 .

[0072] For example, Figure 3 As shown, two light sources such as laser #1 and laser #2 may project light onto the beam steering device 180 at different angles, so that the two illumination light beams L1 and L2 steered by the beam steering device 180 may have an angle θ therebetween. The angle θ is set so that the illumination light beams L1 and L2 irradiated on and reflected from the object OBJ may be respectively detected at different pixels of the detector array 220. The angle θ may be determined by the resolution of the detector array 220 of the light detector 200 and the performance of other optical elements of the light detector 200. For example, the angle θ may be about 1° or greater.

[0073] The two light sources, laser #1 and laser #2, may emit light substantially simultaneously. For example, laser #1 and laser #2 may emit light simultaneously at the same time, or the two light sources, laser #1 and laser #2, may emit light at different times T1 and T2. For example, the difference between times T1 and T2 may be about 1 μs or less.

[0074] The direction of each illumination beam L1 and L2 can be adjusted by the beam steering device 180 to completely scan a predetermined field of view (FOV) including the object OBJ. The illumination beams L1 and L2 reflected from the object OBJ can propagate toward different pixels, and as shown in FIG. Figure 3 As shown, a lens 280 may be further provided between the object OBJ and the detector array 220 to focus the illumination beams L1 and L2 onto different pixels of the two-dimensional detector array 220. Each pixel of the two-dimensional detector array 220 is connected to a circuit element configured to calculate TOF. For example, the time of flight ToF#1 and the time of flight ToF#2 may be obtained by calculation through the corresponding circuit element.

[0075] The LiDAR device 1000 of the example embodiment may use a point scanning method in which the object OBJ is scanned using point light projected from the scanning optical system 100, and may have a resolution limit due to the limited speed of light. For example, there is a limit to the amount of information (point cloud) about the object that can be obtained within a given frame time (i.e., within a reference time period given for forming one image frame of the object), and therefore, the resolution of the LiDAR device 1000 is limited based on the amount of information about the object obtained.

[0076] The following table illustratively shows the approximate round trip time, resolution limit and horizontal resolution according to the distance to the object when the frame rate is 20 Hz, that is, when the frame time is 1 / 20 second. The horizontal resolution is shown for two cases where the vertical resolution is 60 and 30 respectively.

[0077] [Table 1]

[0078]

[0079] As shown in Table 1, the spatial resolution achievable within a given frame time and a given field of view is limited, and the frame rate is negatively affected when the field of view is increased while maintaining spatial resolution. That is, the frame time increases. This performance degradation increases as the distance to the object increases.

[0080] In order to improve the resolution limit, the LiDAR device 1000 of the exemplary embodiment uses two or more light sources and maintains different illumination angles so that the light projected from the multiple light sources can be detected by the light detector 200 respectively. Therefore, the resolution can be increased in proportion to the number of light sources. For example, the resolution value shown in Table 1 above can be increased to the product of the resolution value and the number of light sources of the LiDAR device 1000.

[0081] Figure 4A and Figure 4B It is shown Figure 2An example of a beam steering device 180 of the LiDAR device 1000 shown in FIG. 1 and a diagram of the principles of point scanning using the example beam steering device.

[0082] refer to Figure 4A , by mechanically rotating the scanning mirror to adjust the direction of the reflective surface of the scanning mirror SM, thereby adjusting the incident light L i The incident light L can be turned according to the rotation angle of the scanning mirror SM. i The direction of the steering is adjusted sequentially to direction L S1 , L S2 and L S3 Although the scanning mirror SM is shown as rotating uniaxially, the scanning mirror SM is not limited thereto. The scanning mirror SM can rotate biaxially. That is, the scanning mirror SM can rotate around two rotation axes. In addition, although the scanning mirror SM is shown as having a single reflective surface, this is a non-limiting example. In one example, the scanning mirror SM can have an array of mirror elements, and the direction of each mirror element can be adjusted so that the incident light L i Turn towards object OBJ.

[0083] refer to Figure 4B The optical phased array OPA may include a plurality of channels CH1, CH2, .... Channels CH1, CH2, ... may be provided with a plurality of channels for changing the incident light L i The phase change value of the phase is used to adjust the incident light L i Direction of steering and output.

[0084] Each channel CH1, CH2, ... of the optical phased array OPA may include a sub-wavelength shaped element for electrically adjusting the incident light L i phase change value.

[0085] The optical phased array OPA can be an optical waveguide based on silicon photonics, where the incident light L i The path of the incident light L is divided into multiple paths in multiple channels to i The optical waveguide may include phase retarders respectively arranged in each path, and the length of each path and / or the degree of phase delay in the phase retarder may be adjusted to change the incident light L i Direction of steering and output.

[0086] The optical phased array OPA is along the incident light L generated in channels CH1, CH2, etc. i The combination of phase changes determines the direction of the incident light L i For example, the incident light L can be redirected according to the combination of phase changes. i The direction of steering and output is adjusted sequentially to direction LS1 , L S2 and L S3 .

[0087] Figure 5 It is shown Figure 2 A block diagram of an example structure of the processor 300 of the LiDAR device 1000 shown in FIG. Figure 6 It is shown by Figure 5 A diagram showing an example of processor 300 dividing an object region is shown.

[0088] The processor 300 may include an object region divider 330 and an analyzer 350. Codes or program instructions for operating the object region divider 330 and the analyzer 350 may be stored in a memory of the LiDAR device 1000 and may be executed by the processor 300.

[0089] The object region divider 330 may divide a predetermined FOV including the object OBJ into as many partition regions as the number of the plurality of light sources of the LiDAR apparatus 1000 . Figure 6 An example is shown in which the FOV is divided into 6 partitioned areas when the number of the plurality of light sources is 6. However, this is merely an example. That is, the number or shape of the partitioned areas is not limited thereto.

[0090] The object region divider 330 may generate a scanning control signal and apply the scanning control signal to the scanning optical system 100 so that the scanning optical system 100 may scan the separated regions. Figure 4A When the scanning mirror SM shown in FIG. 1 is a scanning mirror SM, the scanning control signal can be a rotation drive control signal for controlling the rotation direction and the rotation angle. Figure 4B When the optical phased array OPA is shown in FIG. 1 , the scanning control signal may be a phase control signal to be applied to each channel. The phase control signal may be an electrical signal of a component to be applied to the channel, or may be a phase delay signal of a phase delayer to be applied to the channel.

[0091] The analyzer 350 may analyze the position and shape of the object OBJ by considering all illumination angles of light projected onto the object OBJ and the TOF calculated based on the illumination angles.

[0092] Figure 7 It is shown Figure 2 2 is a diagram of an example circuit configuration of the light detector 200 of the LiDAR device 1000 shown in FIG.

[0093] The light detector 200 may include a light detecting element 222 and a time counter 247 configured to measure the TOF of light detected by the light detecting element 222 .

[0094] The photodetector 200 may include: a plurality of current-to-voltage conversion circuits 241 configured to convert a current output from the photodetection element 222 into a voltage; a plurality of amplifiers 243 configured to amplify the voltage output from the current-to-voltage conversion circuit 241; and a plurality of peak detectors 245 configured to detect a peak in a signal amplified by the amplifier 243.

[0095] The light detecting element 222 may respectively detect the plurality of light beams L1 , L2 , and L3 reflected from the object, and may output corresponding current signals.

[0096] The current-to-voltage conversion circuit 241 may convert a current signal output from the light detection element 222 into a voltage signal.

[0097] The amplifier 243 may amplify the voltage signal output from the current-to-voltage conversion circuit 241 .

[0098] The peak detector 245 can detect a peak value in the voltage signal amplified by the amplifier 243. For example, the peak detector 245 can detect the peak value by detecting the rising edge and the falling edge in the electrical signal. In addition, the peak detector 245 can use a constant fraction discriminator (CFD) method to detect the peak value. The peak detector 245 may include a comparator and may output the detected peak value as a pulse signal.

[0099] The time counter 247 can measure the TOF of the light beam detected by the light detection element 222. When the pulse signal is output from the peak detector 245 to the time counter 247, each time counter 247 can measure the TOF of the light beam by counting the number of cycles in the clock signal from the start time when the light source irradiates the object OBJ. In addition, each time counter 247 can store information about the measured TOF of the light beam in a register. Each time counter 247 can be implemented by a time-to-digital converter (TDC).

[0100] The measurement result of the time counter 247 may be transmitted to the processor 300 , and the processor 300 may use the result to perform a data processing process to analyze information about the object, such as the position or shape of the object.

[0101] Figure 8 is a flowchart schematically illustrating a method of driving a LiDAR device according to example embodiments.

[0102] The method of driving the LiDAR device of this example embodiment is similar to the method of driving the LiDAR device of the reference Figure 1The method of driving a LiDAR device described differs in that the number of light sources to be driven is selected, and light is projected to an object using the selected number of light sources. The method can be selectively used in situations where all multiple light sources do not have to be used together.

[0103] First, the number of light sources to be driven is selected by considering frame time and image resolution (S101). The number of light sources may be one or more.

[0104] Next, light is projected onto the object at different illumination angles using the selected light sources (S103). The FOV including the object is divided into a plurality of regions according to the number of selected light sources, and the regions can be scanned using the selected light sources. As described above, the different illumination angles can be different from each other to the extent that the light beams can be detected separately.

[0105] Lights projected onto an object at different illumination angles and reflected from the object are respectively detected ( S200 ), and information on a position and shape of the object is obtained using the detected lights ( S300 ).

[0106] According to the method of driving the LiDAR device of the exemplary embodiment, information about the object can be obtained at an image resolution equal to or greater than a predetermined value within a given frame time. In this case, the number of light sources to be driven can be selected differently according to the range of the FOV required to analyze the object.

[0107] Fig. 9 is a block diagram schematically illustrating a configuration of a LiDAR device 1001 according to an example embodiment, Fig.10 It is shown Fig. 9 001 of the LiDAR device 1001 shown in FIG.

[0108] refer to Fig. 9 , the LiDAR device 1001 may include: a scanning optical system 100, configured to scan an object OBJ with light; a light detector 200, configured to detect light projected from the scanning optical system 100 toward the object OBJ and reflected from the object OBJ; and a processor 301, configured to control the scanning optical system 100 and the light detector 200.

[0109] The scanning optical system 100 includes a light source unit 110 and a beam steering device 180, wherein the light source unit 110 includes a plurality of light sources. The light source unit 110 and the beam steering device 180 can be arranged and driven so that the object OBJ can be scanned using light projected toward the object OBJ at different irradiation angles from the plurality of light sources through the beam steering device 180.

[0110] The LiDAR device 1001 of this example embodiment is Figure 2 The LiDAR apparatus 1000 is different in that the processor 301 drives the scanning optical system 100 after selecting a light source to be driven from among a plurality of light sources of the light source unit 110 and setting the number of divided areas to be formed by dividing the object area.

[0111] Fig. 9 An example is shown in which two light sources (ie, light source 1 and light source N) are selected as the light sources to be driven. In this example, processor 301 drives light source unit 110 in such a manner that light source 1 and light source N emit light but other unselected light sources do not emit light.

[0112] refer to Fig.10 , the processor 301 may include a light source selector 310, an object region divider 330, and an analyzer 350. Codes for operating the light source selector 310, the object region divider 330, and the analyzer 350 may be stored in a memory of the LiDAR device 1001 and may be executed by the processor 301.

[0113] The light source selector 310 sets the number of light sources to be driven by considering a given frame time and image resolution. The number of light sources of the scanning optical system 100 may be selected as the light sources to be driven.

[0114] The object region divider 330 may divide a predetermined FOV including the object OBJ into as many partitioned regions as the set number of light sources. The object region divider 330 may generate a control signal and apply the control signal to the scanning optical system 100 so that the scanning optical system 100 may scan the partitioned regions. As described above, the scanning control signal may be a rotation drive control signal for controlling the rotation direction and rotation angle of the scanning mirror SM, or a phase control signal to be applied to each channel of the optical phased array OPA.

[0115] The analyzer 350 may analyze the position and shape of the object OBJ by considering all angles of light projected onto the object OBJ and TOF calculated based on the angles.

[0116] The LiDAR devices 1000 and 1001 of the example embodiments and the method of driving the LiDAR devices 1000 and 1001 make it possible to obtain more accurate information about the front object and can be used in various electronic devices. Examples of various electronic devices may include autonomous driving devices such as unmanned vehicles, autonomous driving vehicles, autonomous driving robots or autonomous driving drones, mobile communication devices, and Internet of Things devices.

[0117] Each of the LiDAR devices 1000 and 1001 of the example embodiments may include: a processor; a memory for storing and executing program data, a permanent storage such as a disk drive, a communication port for communicating with an external device, and a user interface device such as a touchpad, a key or a button. The method embodied as a software module or algorithm can be stored on a computer-readable recording medium as a non-transitory computer-readable code or program instruction that can be executed by a processor. Examples of computer-readable recording media include magnetic storage media (e.g., read-only memory (ROM), random access memory (RAM), floppy disks, and hard disks) and optical recording media (e.g., CD-ROMs and DVDs). The computer-readable recording medium can also be distributed on networked computer systems so that the computer-readable code can be stored and executed in a distributed manner. The medium can be read by a computer, stored in a memory, and executed by a processor.

[0118] Example embodiments can be implemented as function blocks and various processing operations. Function blocks can be implemented with various hardware and / or software configurations that perform specific functions. For example, example embodiments can use integrated circuit configurations that can perform various functions under the control of a microprocessor or other control device, such as memory, processing, logic, lookup tables, etc. In a manner similar to the manner in which the elements of the example embodiments can be programmed with software or executed by software elements, example embodiments can be implemented with scripting languages ​​or programming languages ​​such as C, C++, Java, assembly, etc., including various algorithms implemented by a combination of data structures, processes, routines, or other programming configurations. Functional aspects can be implemented by algorithms executed in one or more processors. In addition, example embodiments can use converted technologies to establish electronic environments, process signals, and / or process data. Terms such as "mechanism", "element", "device", and "configuration" can be used extensively and are not limited to mechanical configurations and physical configurations. These terms can have the meaning of a series of software routines associated with a processor, etc.

[0119] The specific implementations described herein are merely examples and do not limit the scope of the present disclosure. In order to simplify the description, conventional electronic configurations, control systems, software, and other functional aspects of the system may be omitted. In addition, the line connections or connecting members between the elements depicted in the drawings represent functional connections and / or physical or circuit connections by way of example, and in practical applications, they may be replaced or implemented as various other functional connections, physical connections, or circuit connections.

[0120] According to the LiDAR device and the method of driving the LiDAR device, image resolution may be increased in proportion to the number of point light sources.

[0121] Depending on the LiDAR device and the method of driving the LiDAR device, a higher image resolution and / or a wider FOV may be achieved for a given frame time, or the frame time may be shortened for a given image resolution and a given FOV.

[0122] It should be understood that the exemplary embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects in each exemplary embodiment should typically be considered as applicable to other similar features or aspects in other embodiments.

[0123] Although example embodiments have been described with reference to the drawings, workers skilled in the art will recognize that various changes in form and details may be made without departing from the spirit and scope of the invention as defined by the claims.

Claims

1. A light detection and ranging LiDAR device, comprising: a scanning optical system comprising a plurality of light sources and a beam steering device, the scanning optical system being configured to scan an object using a plurality of illumination beams projected toward the object from the plurality of light sources at a plurality of illumination angles, respectively; a light detector including a plurality of pixel regions configured to respectively detect a plurality of illumination light beams projected toward the object at the plurality of illumination angles and reflected from the object; as well as a processor configured to control the scanning optical system and the light detector and obtain information about the object based on the plurality of illumination light beams detected by the light detector, The processor is further configured to: set the number of light sources to be used based on a reference time period and an image resolution given for forming one image frame of the object, and control the scanning optical system to select a light source corresponding to the set number from the plurality of light sources and project a plurality of illumination light beams toward the object at a plurality of illumination angles using the selected light source to scan the object, and The amount of information obtained about the object is related to the number of light sources provided and the distance to the object.

2. The LiDAR device according to claim 1, wherein: An angle between a plurality of illumination light beams projected from the plurality of light sources toward the object is equal to or greater than an angular resolution of the light detector.

3. The LiDAR device according to claim 1, wherein: The plurality of pixel areas are disposed in the photodetector such that a plurality of illumination light beams projected onto an object at the plurality of illumination angles and reflected from the object are incident on different pixel areas among the plurality of pixel areas.

4. The LiDAR device according to claim 1, wherein: An angle between the plurality of illumination light beams projected from the plurality of light sources toward the object is equal to or greater than 1°.

5. The LiDAR device according to claim 1, wherein: The selected light source is configured to emit a plurality of illumination beams toward the object simultaneously or within a predetermined time period.

6. The LiDAR device according to claim 5, wherein: The predetermined period of time is 1 μs or shorter.

7. The LiDAR device according to claim 1, wherein: The processor is further configured to determine a distance to the object based on the plurality of illumination angles and flight times of the plurality of illumination beams reflected from the object, and perform data processing to analyze a position of the object and a shape of the object.

8. The LiDAR device according to claim 1, wherein: The processor is further configured to control the scanning optical system to scan the object by dividing a region of the object into a plurality of regions corresponding to the number of the provided light sources.

9. The LiDAR device according to claim 1, wherein: The plurality of pixel regions respectively include a plurality of light detection elements, and Each of the plurality of light detection elements includes at least one of an avalanche photodiode and a single photon avalanche diode.

10. The LiDAR device according to claim 1, wherein: The light detector comprises: A plurality of time counters are configured to respectively measure flight times of the plurality of illumination light beams detected by the plurality of pixel regions.

11. The LiDAR device according to claim 10, wherein: The light detector further comprises: a plurality of current-to-voltage conversion circuits configured to convert a plurality of currents respectively output from the plurality of pixel regions into a plurality of voltages; a plurality of amplifiers configured to amplify the plurality of voltages respectively output from the plurality of current-to-voltage conversion circuits; and The plurality of peak detectors are configured to respectively detect a plurality of peaks in the plurality of signals amplified by the plurality of amplifiers.

12. The LiDAR device according to claim 1, wherein: The beam steering device includes a scanning mirror configured to adjust an illumination angle of each of a plurality of illumination beams projected from the plurality of light sources by mechanical rotation.

13. The LiDAR device according to claim 1, wherein: The beam steering device includes an optical phased array configured to adjust an illumination angle of each of a plurality of illumination beams projected from the plurality of light sources by phase control.

14. The LiDAR device according to claim 1, wherein: The image resolution of an image of the object is proportional to the number of light sources provided.

15. A method for driving a light detection and ranging LiDAR device, the method comprising: setting the number of light sources to be used based on a given reference time period and an image resolution for forming one image frame of the object; projecting a plurality of illumination beams toward the object at a plurality of illumination angles using a light source corresponding to the set number selected from the plurality of light sources; respectively detecting a plurality of illumination light beams projected toward the object at the plurality of illumination angles and reflected from the object; as well as obtaining information about the position and shape of the object based on the detection, The amount of information obtained is related to the number of light sources provided and the distance to the object.

16. The method according to claim 15, wherein: An angle between a plurality of illumination light beams projected from the plurality of light sources toward the object is equal to or greater than an angular resolution of the light detector.

17. The method according to claim 15, wherein: The selected light source projects a plurality of illumination beams toward the object simultaneously or within a predetermined time period.

Images