Measuring device, control program for measuring device, and computer-readable recording medium in which computer program is recorded

Abstract

To suppress the occurrence of a trouble attributable to a mechanical composition, according to a downsized mechanical composition for projecting and receiving light, as compared with a scanning type measurement device equipped with a polygon mirror.SOLUTION: A measuring device comprises: a light projector having a plurality of light-emitting units arranged in one row or in a lattice form; a light receiver having a plurality of light-receiving units arranged in one row or in a lattice form and respectively corresponding to the plurality of light-emitting units; and a controller. The controller causes the plurality of light-emitting units to emit light sequentially at mutually different emission timings and causes the plurality of light-receiving units to respectively receive reflected light having been emitted from each light-emitting unit corresponding to each light-receiving unit and having returned after being reflected by a measurement object. Then, the controller performs processing related to the measurement object on the basis of the light emission timing of each light-emitting unit and the light reception timing of each light-receiving unit corresponding to each other.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The technology disclosed in this specification relates to a measurement device. [Background technology]

[0002] With the advancement of AD (Autonomous Driving) and ADAS (Advanced Driver-Assistance Systems), research and development of LiDAR (Light Detection and Ranging) is underway as one of the measurement devices used to grasp the surrounding environment and estimate the vehicle's position while driving.

[0003] Among measurement devices, there is known a scanning type measurement device that uses a polygon mirror. In this measurement device, laser light from a laser light source is reflected by a polygon mirror and irradiated onto a measurement object, and the reflected light that is reflected back from the measurement object is received. By moving the irradiation position of the laser light on the measurement object in a predetermined scanning direction as the polygon mirror rotates, information (shape, etc.) about the measurement object in the scanning direction can be obtained (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2020 / 117912 Summary of the Invention [Problem to be solved by the invention]

[0005] The above-mentioned scanning-type measuring device requires a mechanical configuration, such as a polygon mirror, a rotation mechanism for rotating the polygon mirror, a drive motor for transmitting power to the rotation mechanism, etc. For this reason, scanning-type measuring devices are prone to problems caused by the mechanical configuration, and there is room for improvement.

[0006] This specification discloses a technique that can solve the above-mentioned problems. [Means for solving the problem]

[0007] The technology disclosed in this specification can be realized, for example, in the following forms.

[0008] (1) A measuring device disclosed in this specification includes a light projector having a plurality of light-emitting elements arranged in a line or a grid, a light receiver having a plurality of light-receiving elements arranged in a line or a grid and corresponding to each of the plurality of light-emitting elements, and a controller. The controller sequentially controls the plurality of light-emitting elements to emit light at different emission timings, controls each of the plurality of light-receiving elements to receive light that is emitted from the light-emitting element corresponding to the light-receiving element and reflected back from the object to be measured, and performs processing related to the object to be measured based on the emission timing of each of the corresponding light-emitting elements and the reception timing of each of the corresponding light-receiving elements. Compared to a scanning-type measuring device equipped with a polygon mirror, this measuring device has fewer mechanical components for light projection and reception, thereby reducing the occurrence of problems caused by the mechanical components.

[0009] (2) In the above-described measuring device, the plurality of light receiving units may include a plurality of the light receiving units belonging to a first group and a plurality of the light receiving units belonging to a second group different from the first group, the controller may have a common memory and a common processing unit that performs measurements on the object to be measured, and the controller may write a group of light receiving data corresponding to the light receiving timing of the plurality of light receiving units belonging to the first group to the common memory during a first period, and during a second period after the first period, cause the common processing unit to read the group of light receiving data of the first group written to the common memory to perform measurements on the object to be measured, and write a group of light receiving data corresponding to the light receiving timing of the plurality of light receiving units belonging to the second group to the common memory. This measuring device may enable miniaturization of the memory for measurements on the object to be measured and standardization of its configuration.

[0010] (3) In the above-described measuring device, the controller may be configured to adjust the voltage applied to at least one of the light-emitting units based on the temperature and light-emission intensity characteristics of the at least one light-emitting unit so as to reduce the difference in light-emission intensity before and after a temperature change. This measuring device can suppress variations in light-emission intensity caused by temperature changes of the light-emitting units.

[0011] (4) In the above measuring device, the controller may acquire the emission intensities of at least a first light-emitting unit and a second light-emitting unit among the plurality of light-emitting units, and adjust the voltage applied to at least one of the first light-emitting unit and the second light-emitting unit based on the acquired emission intensities of the first light-emitting unit and the second light-emitting unit so as to reduce the difference in emission intensity between the first light-emitting unit and the second light-emitting unit. This measuring device can suppress variations in emission intensity between the first light-emitting unit and the second light-emitting unit.

[0012] (5) In the above measurement device, the light receiving unit may be a SPAD, and the controller may adjust the voltage applied to at least one of the plurality of light receiving units based on the temperature and breakdown voltage characteristics of the light receiving unit so as to reduce the difference in photon detection efficiency before and after a temperature change. This measurement device can suppress variations in photon detection efficiency caused by temperature changes in the light receiving unit.

[0013] The technology disclosed in this specification can be realized in various forms, such as a measuring device, a control method for a measuring device, a control program for a measuring device, and a computer-readable recording medium on which a computer program is recorded. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a block diagram showing a schematic configuration of a measurement device 10 according to an embodiment. [Figure 2] Time chart showing data processing of point cloud data for each horizontal line [Figure 3] FIG. 10 is an explanatory diagram illustrating a data table showing the correspondence relationship between light-emitting voltage and temperature; [Figure 4] Graph showing breakdown voltage vs. temperature DETAILED DESCRIPTION OF THE INVENTION

[0015] A. Implementation: A-1. Configuration of the measuring device 10: FIG. 1 is a block diagram illustrating a schematic configuration of a measurement device 10 according to this embodiment. The measurement device 10 is a flash-type LiDAR. As illustrated in FIG. 1, the measurement device 10 includes a projector 20, a receiver 30, and a controller 90. The projector 20 includes a plurality of light-emitting elements (not shown) arranged in a grid pattern (two-dimensionally). Specifically, the projector 20 includes a plurality of light-emitting arrays 23 arranged vertically. Each light-emitting array 23 includes a plurality of light-emitting elements arranged linearly (one-dimensionally) in the horizontal direction. The receiver 30 includes a plurality of light-receiving elements 33 arranged in a grid pattern. The light-receiving elements 33 correspond to the light-emitting elements of the projector 20. The controller 90 sequentially controls the light-emitting elements 33 to emit light at different emission timings, and controls each of the light-receiving elements 33 to receive reflected light L2, which is emitted from the light-emitting element corresponding to the light-receiving element 33 and reflected by the measurement target W and returned from the light-receiving element 33. The controller 90 measures the difference between the light emission timing of each corresponding light-emitting element and the light reception timing of each corresponding light-receiving element 33 (time of flight of the laser light, hereinafter referred to as "TOF" (Time of Flight)), and acquires information about the measurement object W. The light-emitting element is an example of a light-emitting unit, and the light-receiving element 33 is an example of a light-receiving unit.

[0016] The measuring device 10 is mounted on, for example, a vehicle (not shown) equipped with AD or ADAS. For example, while the vehicle is traveling, the measuring device 10 assists in detecting objects such as people and other vehicles, and provides various information to other devices and users that is useful for ensuring the safety of the vehicle driver and those around the vehicle, and for reducing damage to surrounding objects while the vehicle is being driven.

[0017] The light projector 20 includes a light source 22 , a light projection optical system 24 , a light projection control device 26 , a selector circuit 21 , a switching unit 25 , a channel setting unit 27 , a laser power supply 28 , and a voltage adjustment circuit 29 .

[0018] The light source 22 has the above-mentioned plurality of light-emitting arrays 23. Each light-emitting array 23 has a plurality of light-emitting elements lined up in the horizontal direction. The plurality of light-emitting arrays 23 are arranged so as to be lined up at equal intervals in the vertical direction. With this configuration, the light source 22 has a plurality of light-emitting elements arranged in a lattice pattern. The light-emitting elements are, for example, laser diodes or surface-emitting type laser light-emitting elements (e.g., VCSELs (Vertical Cavity Surface Emitting Lasers), hereinafter referred to as "surface-emitting elements"). The light source 22 is a surface-emitting element array (e.g., a VCSEL array) in which a plurality of surface-emitting elements are arranged one-dimensionally or two-dimensionally on a substrate (e.g., a semiconductor substrate, a ceramic substrate, etc.).

[0019] The light projection optical system 24 adjusts the light distribution of the emitted light L1 by, for example, applying optical effects (such as refraction, scattering, or diffraction) to the light emitted by the light source 22. The light projection optical system 24 is configured using optical components such as various lenses, such as collimating lenses, and reflecting mirrors (mirrors).

[0020] The light-projection control device 26 sequentially outputs trigger signals S1 indicating the light-emitting timing of each light-emitting element of the light source 22 to the selector circuit 21. The selector circuit 21 selectively applies the trigger signals S1 output from the light-projection control device 26 to the plurality of light-emitting arrays 23. The light source 22 may also perform continuous light emission by multiple trigger emissions indicating continuous emission within a horizontal synchronization timing.

[0021] The light-projection control device 26 sequentially outputs channel selection signals S2 to the channel setting unit 27 in response to a horizontal synchronization signal (HSYNC) from the control circuit 45. The channel selection signal S2 includes channel selection information for individually selecting one of the multiple light-emitting arrays 23 (channels) included in the light source 22, and a voltage setting value for the light-emitting voltage for each channel. The channel setting unit 27 controls the switching unit 25 based on the channel selection signal S2 (channel selection information). The switching unit 25 sequentially switches the light-emitting arrays 23 to be selected by the selector circuit 21 based on the channel selection information. In this embodiment, the switching unit 25 sequentially selects the light-emitting arrays 23 one by one, for example, from the light-emitting array 23 located in the top row to the light-emitting array 23 located in the bottom row. The light-projection control device 26 outputs a channel selection signal S2 in which an initial light-projection channel is selected for each frame in response to the timing of a vertical synchronization signal (VSYNC) from the control circuit 45.

[0022] The channel setting unit 27 controls the voltage adjustment circuit 29 based on the channel selection signal S2 (the voltage setting value of the light-emitting voltage for each channel). The laser power supply 28 generates a light-emitting voltage for causing the light-emitting array 23 (light-emitting element) to emit light. The voltage adjustment circuit 29 adjusts (changes) the voltage value of the light-emitting voltage provided from the laser power supply 28 to the light source 22 (light-emitting array 23) based on the voltage setting value of the light-emitting voltage for each channel.

[0023] With this configuration, in the floodlight 20, when the light-projection control device 26 outputs a channel selection signal S2 that selects, for example, channel 1, the selector circuit 21 selects the top-level light-emitting array 23. As a result, the trigger signal S1 from the light-projection control device 26 is provided only to the top-level light-emitting array 23. As a result, each time the light-emitting array 23 receives the trigger signal S1, multiple light-emitting elements arranged in the top-level light-emitting array 23 may emit light simultaneously or separately. The voltage adjustment circuit 29 sets the light-emitting voltage provided to the light source 22 (top-level light-emitting array 23) to the voltage setting value for channel 1 specified by the channel selection signal S2. As a result, each light-emitting element of the top-level light-emitting array 23 emits light with an emission intensity corresponding to the voltage setting value for channel 1.

[0024] Next, when the light projection control device 26 outputs a channel selection signal S2 that selects, for example, channel 2, the trigger signal S1 from the light projection control device 26 is provided only to the second-highest light-emitting array 23. As a result, each time the light-emitting array 23 receives the trigger signal S1, the multiple light-emitting elements arranged in the second-highest light-emitting array 23 emit light simultaneously or sequentially in divided portions. The voltage adjustment circuit 29 sets the light-emitting voltage provided to the light source 22 (the second-highest light-emitting array 23) to the voltage setting value for channel 2 specified by the channel selection signal S2. As a result, each light-emitting element of the second-highest light-emitting array 23 emits light with a light intensity according to the voltage setting value for channel 2. In this way, the multiple light-emitting elements of each light-emitting array 23 correspond to pixel positions in the horizontal direction H in the spatial coordinate system, and the channels of the light-emitting array 23 correspond to pixel positions in the vertical direction V in the spatial coordinate system (see FIG. 1).

[0025] The projector 20 further includes a voltage sensor 64, a temperature sensor 66, and a light-receiving sensor 68. The voltage sensor 64 outputs a detection signal corresponding to the voltage value of the light-emitting voltage applied to the light source 22 (light-emitting array 23). The temperature sensor 66 is disposed near the light source 22 (light-emitting array 23), and outputs a detection signal corresponding to the temperature of the light source 22. The light-receiving sensor 68 is disposed in a position where it can receive a portion of the emitted light L1 emitted by the light source 22 (light-emitting element), and outputs a detection signal corresponding to the light emission intensity of the light source 22.

[0026] The light-projection control device 26 inputs a signal indicating the light-emitting timing of each light-emitting element to the TOF measurement device 40. The light-projection control device 26 periodically and repeatedly controls the on / off of a current flowing through the light-emitting element, for example, to cause the light-emitting element to emit light periodically and repeatedly.

[0027] The light receiver 30 includes a light receiving device 32, a light receiving optical system , a receiving circuit , a flip-flop 37, and an AND circuit .

[0028] The light receiving optical system 34 collects reflected light L2, which is light L1 emitted from the projector 20 and reflected by the measurement target W or the like, onto the light receiving device 32. The light receiving optical system 34 is configured using optical components such as various lenses, such as a collecting lens, various filters, such as a wavelength filter, and a reflecting mirror (mirror).

[0029] The light receiving device 32 has a plurality of light receiving elements 33. The light receiving elements 33 are, for example, photodiodes, SPADs (Single Photon Avalanche Diodes), APDs (Avalanche Photodiodes), PPDs (Pixelated Photon Detectors), balanced photodetectors, etc. The light receiving device 32 photoelectrically converts the reflected light L2 incident from the light receiving optical system 34 to generate a light receiving signal with a current level or voltage level corresponding to the intensity of the reflected light L2.

[0030] The receiving circuit 36 ​​receives the light receiving signals sequentially output from the light receiving device 32. The TOF measurement device 40 outputs a count start signal for selecting a light receiving element to the flip-flop 37 in synchronization with the output of the trigger signal S1. The flip-flop 37 outputs a light receiving signal (including a signal indicating the light receiving timing at which the reflected light L2 was received) generated by the light receiving element 33 corresponding to the light emitting element that emitted light in response to the trigger signal S1, based on the count start signal from the TOF measurement device 40. The AND circuit 38 sequentially validates the light receiving signals output from the flip-flop 37 at a timing according to the high-speed clock C.

[0031] The photoreceiver 30 further includes a voltage adjustment circuit 74 and a photoreceiving power supply 77. The photoreceiving power supply 77 generates a photoreceiving voltage to be applied to the photoreceiving device 32 (photoreceiving element 33). The voltage adjustment circuit 74 adjusts (changes) the voltage value of the photoreceiving voltage to be applied to the photoreceiving device 32 (photoreceiving element 33) based on the voltage setting value of the photoreceiving voltage for each channel.

[0032] The light receiver 30 further includes a voltage sensor 76 and a temperature sensor 72. The voltage sensor 76 outputs a detection signal corresponding to the voltage value of the light receiving voltage applied to the light receiving device 32 (light receiving element 33). The temperature sensor 72 is disposed near the light receiving device 32 (light receiving element 33) and outputs a detection signal corresponding to the temperature of the light receiving element 33.

[0033] The measurement device 10 further includes a TOF measurement device 40, a framing memory 42, a control circuit 45, a DMAC (Direct Memory Access Controller) 43, a main memory 61, and a communication I / F (Interface) 62.

[0034] The TOF measurement device 40 determines the TOF based on a signal indicating the light emission timing input from the light projection control device 26 and a signal indicating the light reception timing input from the light receiving device 32 (AND circuit 38). The TOF measurement device 40 has, for example, a time measurement IC (Integrated Circuit) equipped with a TDC (Time to Digital Converter) circuit. The TOF measurement device 40 inputs the determined TOF (position information indicating the relative position of the measurement point) and the light reception signal input from the light receiving device 32 (pixel information such as the received light intensity at the measurement point) to the control circuit 45.

[0035] The framing memory 42 has an area capable of recording one horizontal line's worth of TOF and light reception signals (hereinafter referred to as "point cloud data"). The framing memory 42 is configured, for example, with a ROM, RAM, or SSD (solid-state drive). The framing memory 42 is an example of a shared memory. The DMAC 43 reads out the point cloud data for one horizontal line recorded in the framing memory 42 and transfers it to the main memory 61. The point cloud data is an example of a light reception data group.

[0036] The control circuit 45 has a processor (such as a CPU (Central Processing Unit), MPU (Micro Processing Unit), ASIC (Application Specific Integrated Circuit), FPGA (Field Programmable Gate Array), and DSP (Digital Signal Processor)). Based on the TOF and the light receiving signal input from the TOF measurement device 40, the control circuit 45 generates information used for various measurements such as detection and distance measurement of the measurement target W. This information includes, for example, a histogram used in time-correlated signal photon counting, distances to each point on the measurement target W, and a point cloud (point cloud information). The control circuit 45 also controls the light-projection control device 26 and the light-receiving device 32. For example, the control circuit 45 controls the light-projection control device 26 and the light-receiving device 32 to control the light-emitting timing and light-receiving timing described above so as to speed up or optimize the process for generating the histogram. The information generated by the control circuit 45 is provided (transmitted) via the communication I / F 62 to devices that use the information (hereinafter referred to as "various use devices").

[0037] Various utilization devices perform, for example, the creation of environmental maps using point clouds, and self-location estimation (SLAM (Simultaneous Localization and Mapping)) using scan matching algorithms (NDT (Normal Distributions Transform), ICP (Iterative Closest Point), etc.).

[0038] The main memory 61 is composed of, for example, ROM, RAM, HDD (hard disk drive), and SSD. The main memory 61 stores various programs and data, and is used as a work area and data storage area when executing various processes. For example, the main memory 61 stores computer programs for executing measurement processes and data processing, which will be described later. These computer programs are provided in a state stored on a computer-readable recording medium (not shown), such as a CD-ROM, DVD-ROM, or USB memory, or are provided in a state that allows them to be obtained from an external device via a communication interface (not shown), and are stored in the main memory 61 in a state that allows them to run on the measurement device 10.

[0039] A-2. Point cloud data processing: Fig. 2 is a time chart showing the data processing of point cloud data for each horizontal line. Fig. 2 illustrates the data processing of point cloud data for six horizontal lines. The control circuit 45 frames each horizontal line of point cloud data from the multiple light-receiving elements 33 corresponding to one channel of the light-emitting array 23, and performs processing related to the measurement object on a frame-by-frame basis. Processing related to the measurement object includes, for example, distance calculation, transfer format generation, data transfer, abnormality monitoring, and automatic control.

[0040] Specifically, in synchronization with the output timing of the channel selection signal S2 of each channel, point cloud data for one horizontal line from the plurality of light receiving elements 33 corresponding to the light emitting array 23 of each channel (hereinafter referred to as "point cloud data of N (N=1, 2, . . . 6) channels") is sequentially written into the framing memory 42. In this embodiment, the framing memory 42 has two upper storage areas and can simultaneously store point cloud data for two channels.

[0041] After all of the point cloud data of one channel (see "#1" in FIG. 2) has been written to one storage area of ​​the framing memory 42, in synchronization with the output timing of the channel selection signal S2 of the second channel, the point cloud data of the second channel (see "#2" in FIG. 2) begins to be written to the other storage area of ​​the framing memory 42. In parallel with this, the control circuit 45 transfers the point cloud data of one channel stored in the framing memory 42 to the main memory 61.

[0042] Next, in synchronization with the output timing of the channel selection signal S2 for the three channels, the three-channel point cloud data (see "#3" in FIG. 2) begins to be written to one storage area of ​​the framing memory 42. In parallel with this, the control circuit 45 transfers the two-channel point cloud data stored in the framing memory 42 to the main memory 61. The control circuit 45 also sequentially executes a distance measurement calculation process, a transfer format generation process, a data transfer process, and a monitoring process for the one-channel point cloud data stored in the main memory 61. The multiple light receiving elements 33 corresponding to the one-channel light emitting array 23 (the uppermost horizontal line) are an example of a multiple light receiving unit belonging to a first group, and the multiple light receiving elements 33 corresponding to the two-channel light emitting array 23 (the second-highest horizontal line) are an example of a multiple light receiving unit belonging to a second group. The control circuit 45, the main memory 61, and the communication I / F 62 are an example of a common processing unit.

[0043] The distance measurement calculation process is a calculation process for measuring the distance to the measurement target W (shape, relative positional relationship, etc.) based on point cloud data for one horizontal line. The transfer format generation process is a process for generating transfer data in a format for transfer to an external device (various utilization devices, etc.) based on measurement result data. The data transfer process is a process for transferring the transfer data to the external device via the communication I / F 62. The monitoring process is a process for detecting various abnormalities. For example, the control circuit 45 detects an abnormality (e.g., overvoltage) in the light-emitting voltage applied to the light source 22 (light-emitting array 23) based on a detection signal from the voltage sensor 64. The control circuit 45 detects a temperature abnormality (e.g., overheating) of the light source 22 (light-emitting array 23) based on a detection signal from the temperature sensor 66. The control circuit 45 detects an abnormality in the emission intensity of the light L1 emitted from the light source 22 (light-emitting array 23) based on a detection signal from the light-receiving sensor 68 (e.g., emission intensity lower than a predetermined lower limit, emission intensity higher than a predetermined upper limit, etc.). The monitoring process further includes a light emission intensity control process and a breakdown voltage control process, which will be described later.

[0044] A-3. Light intensity control process: The control circuit 45 adjusts the light-emitting voltage applied to the light source 22 based on the temperature and light-emitting intensity characteristics of the plurality of light-emitting elements included in the light source 22 so as to reduce the difference in light-emitting intensity before and after a temperature change. In this embodiment, the control circuit 45 adjusts the light-emitting voltage for each light-emitting array 23, for example.

[0045] FIG. 3 is an explanatory diagram illustrating a data table showing the correspondence relationship between light-emitting voltage and temperature. The voltage values ​​in FIG. 3 are the optimum values ​​of the applied voltage to be applied to the light-emitting array 23 of each channel so that the light-emitting intensity of the light-emitting element of the light-emitting array 23 reaches a predetermined target intensity. As shown in FIG. 3, the light-emitting arrays 23 of multiple channels (N) may have different characteristics between temperature and the optimum value of the applied voltage. For example, even if the temperature is the same, the optimum value of the applied voltage may differ for each channel (see FIG. 3). Examples of causes of this include differences between individual light-emitting arrays 23 and differences in the length of the wiring between the laser power supply 28 and the light-emitting array 23.

[0046] The control circuit 45 detects the temperature of the light-emitting array 23 based on a detection signal from the temperature sensor 66, and reads out the optimum value of the applied voltage corresponding to the detected temperature from the data table in FIG. 3. The control circuit 45 detects the applied voltage to the light-emitting array 23 based on a detection signal from the voltage sensor 64. The control circuit 45 controls the voltage adjustment circuit 29 based on the detected applied voltage. The voltage adjustment circuit 29 adjusts the applied voltage to the light-emitting array 23 so that it approaches the optimum value. It is preferable that the voltage adjustment circuit 29 has a high slew rate for high voltages.

[0047] Furthermore, in this embodiment, the control circuit 45 detects the light emission intensity of the light-emitting array 23 based on the detection signal from the light-receiving sensor 68, and controls the voltage adjustment circuit 29 so as to reduce the difference between the detected light emission intensity and the target intensity. In other words, the voltage adjustment circuit 29 finely adjusts the voltage applied to the light-emitting array 23 so as to reduce the difference between the light emission intensity and the target intensity. This makes it possible to reduce variations in light emission intensity for all light-emitting elements in the light source 22.

[0048] A-4. Breakdown voltage control: The light receiving elements 33 included in the light receiving device 32 are SPADs. The control circuit 45 adjusts the voltage applied to the light receiving elements 33 included in the light receiving device 32 based on the characteristics of temperature and breakdown voltage so as to reduce the difference in photon detection efficiency before and after a temperature change.

[0049] Figure 4 is a graph showing the relationship between breakdown voltage and temperature. As shown in Figure 4, the higher the temperature of the SPAD, the higher the breakdown voltage. If the temperature of the SPAD rises while the voltage applied to the SPAD is kept constant, the DCR (Dynamic Contrast Ratio) increases, while the PDE (Photon Detection Efficiency) decreases. This is because the breakdown voltage of the SPAD changes as the temperature rises.

[0050] The control circuit 45 detects the temperature of the light-receiving device 32 (light-receiving element 33) based on the detection signal from the temperature sensor 72, and reads the optimal value of the breakdown voltage corresponding to the detected temperature from the data table corresponding to the graph in FIG. 4. The control circuit 45 detects the voltage applied to the light-receiving element 33 based on the detection signal from the voltage sensor 76. The control circuit 45 controls the voltage adjustment circuit 74 based on the detected applied voltage. The voltage adjustment circuit 74 adjusts the voltage applied to the light-receiving element 33 so that it approaches the breakdown voltage after the temperature change. Note that the voltage adjustment circuit 74 is preferably a voltage adjustment circuit with a high slew rate for high voltages. This makes it possible to suppress variations in photon detection efficiency caused by temperature changes of the light-receiving elements 33 for all the light-receiving elements 33 in the light-receiving device 32.

[0051] A-5. Advantages of this embodiment: As described above, the measuring device 10 according to this embodiment is a flash-type LiDAR (see FIG. 1). Therefore, according to this embodiment, compared to a scanning-type measuring device equipped with a polygon mirror, the mechanical configuration for emitting and receiving light is reduced, and therefore, problems caused by the mechanical configuration can be suppressed.

[0052] In this embodiment, the control circuit 45 frames each horizontal line of point cloud data from the plurality of light-receiving elements 33 corresponding to one channel of the light-emitting array 23, and executes processing related to the measurement object in units of frames (see FIG. 2). Therefore, according to this embodiment, it is possible to reduce the size of the memory for measurement related to the measurement object and standardize the configuration, compared to a configuration in which the point cloud data of all the light-receiving elements 33 of the light-receiving device 32 are processed collectively.

[0053] B. Variations: The technology disclosed in this specification is not limited to the above-described embodiments, and can be modified into various forms without departing from the spirit thereof, for example, the following modifications are also possible.

[0054] The configuration of the measurement device 10 in the above embodiment is merely an example and can be modified in various ways. For example, the measurement device 10 may be configured such that the light projector 20 has a plurality of light-emitting elements arranged linearly (one-dimensionally), and the light receiver 30 has a plurality of light-receiving elements arranged linearly (one-dimensionally). Furthermore, at least two or more of the plurality of light-emitting elements may emit light simultaneously.

[0055] In the above embodiment, the control circuit 45 stores the point cloud data in the frame memory 42 for each horizontal line and performs processing related to the measurement object, but the control circuit 45 may store the point cloud data in the frame memory 42 for each of multiple horizontal lines or for each or multiple vertical lines and perform processing related to the measurement object. The control circuit 45 does not need to adjust the voltage applied to the light-emitting array 23 regardless of fluctuations in at least one of the temperature and the light emission intensity. [Explanation of symbols]

[0056] 10: Measuring device 20: Emitter 21: Selector circuit 22: Light source 23: Light-emitting array 24: Emitter optical system 25: Switching unit 26: Emitter control device 27: Channel setting unit 28: Laser power supply 29, 74: Voltage adjustment circuit 30: Receiver 32: Light-receiving device 33: Light-receiving element 34: Light-receiving optical system 36: Receiving circuit 37: Flip-flop 38: AND circuit 40: TOF measuring device 42: Frame memory 43: DMAC 45: Control circuit 61: Main memory 62: Communication I / F (Interface) 64, 76: Voltage sensor 66, 72: Temperature sensor 68: Light-receiving sensor 77: Light-receiving power supply 90: Controller W: Measurement object

Claims

1. a floodlight having a plurality of light-emitting units arranged in a line or a grid; a light receiver having a plurality of light receiving units arranged in a line or a grid, each corresponding to one of the plurality of light emitting units; a controller, The controller The plurality of light-emitting units are sequentially caused to emit light at different light-emitting timings, Each of the plurality of light receiving units receives reflected light that is emitted from each of the light emitting units corresponding to the light receiving unit and is reflected by the measurement object and returned; A measuring device that performs processing related to the measurement object based on the light emission timing of each of the light-emitting elements and the light reception timing of each of the light-receiving elements that correspond to each other.

2. 2. The measuring device according to claim 1, the plurality of light receiving units include a plurality of the light receiving units belonging to a first group and a plurality of the light receiving units belonging to a second group different from the first group, the controller has a common memory and a common processing unit that performs measurements on the measurement object, The controller during a first period, a group of light reception data corresponding to light reception timings of the plurality of light receiving units belonging to the first group is written into the common memory; During a second period after the first period, the common processing unit reads out the group of light receiving data of the first group written in the common memory and performs measurements on the object to be measured, and writes into the common memory a group of light receiving data corresponding to the light receiving timing of the plurality of light receiving units belonging to the second group.

3. 3. The measuring device according to claim 1 or 2, The controller A measuring device that adjusts a voltage applied to at least one of the plurality of light-emitting units based on the temperature and light-emitting intensity characteristics so that the difference in light-emitting intensity before and after a temperature change is small.

4. 3. The measuring device according to claim 1 or 2, The controller acquiring light emission intensities of at least a first light-emitting unit and a second light-emitting unit among the plurality of light-emitting units; a measuring device that adjusts a voltage applied to at least one of the first light-emitting unit and the second light-emitting unit based on the acquired light-emitting intensity of the first light-emitting unit and the light-emitting intensity of the second light-emitting unit so that a difference in light-emitting intensity between the first light-emitting unit and the second light-emitting unit is reduced.

5. 3. The measuring device according to claim 1 or 2, the light receiving unit is a SPAD, The controller A measuring device that adjusts a voltage applied to at least one of the plurality of light receiving sections based on the temperature and breakdown voltage characteristics so that the difference in photon detection efficiency before and after a temperature change is small.

6. a floodlight having a plurality of light-emitting units arranged in a line or a grid; a light receiver having a plurality of light receiving units arranged in a line or a grid and corresponding to each of the plurality of light emitting units; The plurality of light-emitting units are sequentially caused to emit light at different light-emitting timings, Each of the plurality of light receiving units receives reflected light that is emitted from each of the light emitting units corresponding to the light receiving unit and is reflected by the measurement object and returned; A control program for a measurement device that performs processing related to the measurement object based on the light emission timing of each of the light-emitting elements and the light reception timing of each of the light-receiving elements that correspond to each other.

7. a floodlight having a plurality of light-emitting units arranged in a line or a grid; a light receiver having a plurality of light receiving units arranged in a row or a grid, each of the light emitting units corresponding to the light receiving units; The plurality of light-emitting units are sequentially caused to emit light at different light-emitting timings, Each of the plurality of light receiving units receives reflected light that is emitted from each of the light emitting units corresponding to the light receiving unit and is reflected by the measurement object and returned; A computer-readable recording medium having a computer program recorded thereon, the computer program performing processing related to the object to be measured based on the light emission timing of each of the light-emitting elements and the light reception timing of each of the light-receiving elements corresponding to each other.

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