Measuring device, control program for measuring device, and computer-readable recording medium having computer program recorded thereon

Abstract

The present invention suppresses the occurrence of failures caused by a mechanical configuration for projecting and receiving light, to the extent that the mechanical configuration is reduced in comparison with scanning type measuring devices provided with a polygon mirror. This measuring device comprises: a light projector having a plurality of light emitting units that are arranged in one row or in a grid formation; a light receiver having a plurality of light receiving units that are arranged in one row or in a grid formation and that correspond respectively 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 light emission timings; causes each of the plurality of light receiving units to receive reflected light that has been emitted from each of the light emitting units corresponding to each of the light receiving units and has been reflected back from a measurement target object; and performs processing related to the measurement target object on the basis of the light emission timings of the light emitting units and the light reception timings of the corresponding light receiving units.

Description

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

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

[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 traveling.

[0003] Among measurement devices, there is known a scanning type measurement device using 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).

[0004] International Publication No. 2020 / 117912

[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.

[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 causes the plurality of light-emitting elements to emit light at different emission timings, causes each of the plurality of light-receiving elements to receive light that is emitted from the light-emitting element corresponding to the corresponding 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. This measuring device has fewer mechanical components for light projection and reception than a scanning-type measuring device equipped with a polygon mirror, 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 timings of the plurality of light receiving units belonging to the first group to the common memory during a first period, and may cause the common processing unit to read the group of light receiving data of the first group written to the common memory and perform measurements on the object to be measured during a second period that is later than the first period, and may write a group of light receiving data corresponding to the light receiving timings of the plurality of light receiving units belonging to the second group to the common memory during a second period that is later than the first period. 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 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 unit.

[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 a 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 be configured to 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 at least one 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 of 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.

[0014] A block diagram showing the general configuration of a measurement device 10 according to an embodiment. A time chart showing data processing of point cloud data for each horizontal line. An explanatory diagram showing an example of a data table showing the correspondence between light emission voltage and temperature. A graph showing the relationship between breakdown voltage and temperature.

[0015] A. Embodiment: A-1. Configuration of Measuring Device 10: FIG. 1 is a block diagram showing a schematic configuration of the measuring device 10 in this embodiment. The measuring device 10 is a flash-type LiDAR. That is, as shown in FIG. 1, the measuring device 10 includes a light projector 20, a light receiver 30, and a controller 90. The light projector 20 has a plurality of light-emitting elements (not shown) arranged in a grid pattern (two-dimensionally). Specifically, the light projector 20 has a plurality of light-emitting arrays 23 arranged in the vertical direction. Each light-emitting array 23 has a plurality of light-emitting elements arranged in a line (one-dimensionally) in the horizontal direction. The light receiver 30 has a plurality of light-receiving elements 33 arranged in a grid pattern. The plurality of light-receiving elements 33 respectively correspond to the plurality of light-emitting elements of the light projector 20. The controller 90 sequentially causes the plurality of light-emitting elements to emit light at different emission timings, and causes each of the plurality of light-receiving elements 33 to receive reflected light L2 that is emitted from the corresponding light-emitting element 33 and reflected off the measurement object W and returned. The controller 90 measures the difference between the emission timing of each corresponding light-emitting element and the reception timing of each light-receiving element 33 (time of flight of the laser light, hereinafter referred to as "TOF" (Time of Flight)) to acquire information about the measurement object W. The light-emitting elements are an example of a light-emitting unit, and the light-receiving elements 33 are 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. The measuring device 10 assists in detecting objects such as people and other vehicles while the vehicle is traveling, and provides various information to other devices and users that is useful for ensuring the safety of the driver of the vehicle 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 arranged in the horizontal direction. The plurality of light-emitting arrays 23 are arranged so as to be equally spaced along the vertical direction. With this configuration, the light source 22 has a plurality of light-emitting elements arranged in a grid 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 output light L1 by, for example, applying an optical effect (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 set value of 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 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 indicating the initial light-projection channel 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 elements) 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. Therefore, the trigger signal S1 from the light projection control device 26 is provided only to the top-level light-emitting array 23. This allows the multiple light-emitting elements arranged in the top-level light-emitting array 23 to emit light simultaneously or in separate emitters each time the light-emitting array 23 receives the trigger signal S1. 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. Therefore, each light-emitting element in the top-level light-emitting array 23 emits light at an 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 an intensity corresponding 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 periodically and repeatedly emit light.

[0027] The light receiver 30 includes a light receiving device 32 , a light receiving optical system 34 , a receiving circuit 36 ​​, a flip-flop 37 , and an AND circuit 38 .

[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 condensing 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, single photon avalanche diodes (SPADs), avalanche photodiodes (APDs), pixelated photon detectors (PPDs), 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 having 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 apparatus 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 apparatus 40. The AND circuit 38 sequentially validates the light receiving signals output by the flip-flop 37 at a timing according to the high-speed clock C.

[0031] The light receiver 30 further includes a voltage adjustment circuit 74 and a light receiving power supply 77. The light receiving power supply 77 generates a light receiving voltage to be applied to the light receiving device 32 (light receiving element 33). The voltage adjustment circuit 74 adjusts (changes) the voltage value of the light receiving voltage to be applied to the light receiving device 32 (light receiving element 33) based on the voltage setting value of the light receiving 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 apparatus 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 calculates 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 calculated TOF (position information indicating the relative position of the measurement point) and a light reception signal (pixel information such as the received light intensity at the measurement point) input from the light receiving device 32 to a 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), DSP (Digital Signal Processor)). Based on the light receiving signal and TOF input from the TOF measurement device 40, the control circuit 45 generates information used for various measurements such as detection of the measurement object W and distance measurement. The information includes, for example, a histogram used in time-correlated single photon counting, distances to each point on the measurement target W, a point cloud (point cloud information), etc. The control circuit 45 also controls the light-projection control device 26 and the light-receiving device 32. The control circuit 45 controls the light-emitting timing and light-receiving timing described above, for example, by controlling the light-projection control device 26 and the light-receiving device 32, so as to speed up or optimize the processing involved in 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, a ROM, a RAM, a hard disk drive (HDD), or an 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 the data processing described below. These computer programs are provided in a state stored on a computer-readable recording medium (not shown), such as a CD-ROM, a DVD-ROM, or a USB memory, or are provided in a state that allows them to be retrieved 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 be operated on the measurement device 10.

[0039] A-2. Data Processing of Point Cloud Data: Figure 2 is a time chart showing the data processing of point cloud data for each horizontal line. Figure 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 for 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 third channel, the point cloud data for the third channel (see "#3" in FIG. 2) begins to be written to one storage area of ​​the framing memory 42. Concurrently, the control circuit 45 transfers the point cloud data for the second channel stored in the framing memory 42 to the main memory 61. The control circuit 45 also sequentially executes distance measurement calculation processing, transfer format generation processing, data transfer processing, and monitoring processing for the point cloud data for the first channel stored in the main memory 61. The plurality of light receiving elements 33 corresponding to the light emitting array 23 for the first channel (the highest horizontal line) are an example of a plurality of light receiving units belonging to a first group, and the plurality of light receiving elements 33 corresponding to the light emitting array 23 for the second channel (the second highest horizontal line) are an example of a plurality of light receiving units 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 (e.g., 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 for forming 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. Emission Intensity Control Process: The control circuit 45 adjusts the light-emitting voltage applied to the light source 22 based on the temperature and emission intensity characteristics of the plurality of light-emitting elements included in the light source 22 so as to reduce the difference in emission 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 optimal values ​​of the applied voltage to be applied to the light-emitting array 23 of each channel to achieve a predetermined target light-emitting intensity of the light-emitting element. As shown in FIG. 3, the light-emitting arrays 23 of multiple channels (N) may have different characteristics between temperature and the optimal applied voltage. For example, even if the temperature is the same, the optimal applied voltage may differ for each channel (see FIG. 3). Examples of causes of this include individual differences between the light-emitting arrays 23 and differences in the wiring length between the laser power supply 28 and the light-emitting arrays 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 voltage applied 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 voltage applied 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 process: The light-receiving elements 33 of the light-receiving device 32 are SPADs. The control circuit 45 adjusts the voltage applied to the light-receiving elements 33 of the light-receiving device 32 based on the temperature and breakdown voltage characteristics so as to reduce the difference in photon detection efficiency before and after a temperature change.

[0049] 4 is a graph showing the relationship between breakdown voltage and temperature. As shown in FIG. 4, the higher the temperature of the SPAD, the higher the breakdown voltage. If the temperature of the SPAD increases 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 with increasing temperature.

[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 element 33 for all light-receiving elements 33 included in the light-receiving device 32.

[0051] A-5. Advantages of this embodiment: As described above, the measurement device 10 according to this embodiment is a flash-type LiDAR (see FIG. 1). Therefore, according to this embodiment, compared to a scanning-type measurement 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 on a frame-by-frame basis (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 from all of the light-receiving elements 33 of the light-receiving device 32 are processed collectively.

[0053] B. Modifications: The technology disclosed in this specification is not limited to the above-described embodiment, and can be modified in various forms without departing from the spirit of the invention. For example, the following modifications are also possible.

[0054] The configuration of the measuring device 10 in the above embodiment is merely an example and various modifications are possible. For example, the measuring device 10 may be configured such that the light projector 20 has a plurality of light-emitting elements arranged in a line (one-dimensionally), and the light receiver 30 has a plurality of light-receiving elements arranged in a line (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.

[0056] This international application claims priority based on Japanese Patent Application No. 2024-028496, filed on February 28, 2024, the entire contents of which are incorporated herein by reference.

[0057] The above descriptions of specific embodiments of the present invention have been presented for purposes of illustration. They are not intended to be exhaustive or to limit the invention to the precise forms described. Numerous modifications and variations will be apparent to those skilled in the art in light of the above description.

[0058] 10: Measuring device 20: Light emitter 21: Selector circuit 22: Light source 23: Light-emitting array 24: Light-emitting optical system 25: Switching unit 26: Light-emitting control device 27: Channel setting unit 28: Laser power supply 29, 74: Voltage adjustment circuit 30: Light 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 measuring device comprising: 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, each corresponding to one of the plurality of light emitting elements; and a controller, wherein the controller causes the plurality of light emitting elements to emit light sequentially at different light emission timings; causes each of the plurality of light receiving elements to receive light that is emitted from the light emitting element corresponding to each of the light receiving elements and reflected back from the object to be measured; and performs processing related to the object to be measured based on the light emission timings of the corresponding light emitting elements and the light reception timings of the corresponding light receiving elements.

2. A measuring device according to claim 1, wherein 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, and the controller has a common memory and a common processing unit that performs measurements related to the object to be measured, and the controller writes, during a first period, a group of light receiving data corresponding to the light receiving timing of the plurality of light receiving units belonging to the first group into the common memory, and, during a second period after the first period, causes the common processing unit to read out the group of light receiving data of the first group written into the common memory and perform measurements related to 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. A measuring device according to claim 1 or claim 2, wherein the controller adjusts the voltage applied to at least one of the plurality of light-emitting elements based on the characteristics of temperature and light-emitting intensity so that the difference in light-emitting intensity before and after a temperature change is small for the at least one light-emitting element.

4. A measuring device as claimed in claim 1 or claim 2, wherein the controller acquires the light emission intensity of at least a first light-emitting unit and a second light-emitting unit among the plurality of light-emitting units, and adjusts the voltage applied to at least one of the first light-emitting unit and the second light-emitting unit based on the acquired light emission intensity of the first light-emitting unit and the light emission intensity of the second light-emitting unit so as to reduce the difference in light emission intensity between the first light-emitting unit and the second light-emitting unit.

5. A measuring device according to claim 1 or claim 2, wherein the light receiving unit is a SPAD, and the controller adjusts the voltage applied to at least one of the plurality of light receiving units 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.

6. A control program for a measuring device that includes a light projector having a plurality of light-emitting elements arranged in a line or a grid, and a light receiver having a plurality of light-receiving elements arranged in a line or a grid, each corresponding to one of the plurality of light-emitting elements, the program causing the plurality of light-emitting elements to emit light sequentially at different light-emitting timings, causing each of the plurality of light-receiving elements to receive light that is emitted from the light-emitting element corresponding to each of the light-receiving elements and reflected back from the object to be measured, and performing processing related to the object to be measured based on the light-emitting timing of each of the corresponding light-emitting elements and the light-receiving timing of each of the light-receiving elements.

7. A computer-readable recording medium having recorded thereon a computer program for controlling a measuring device comprising: a light projector having a plurality of light-emitting elements arranged in a line or a grid; and a light receiver having a plurality of light-receiving elements arranged in a line or a grid, each corresponding to one of the plurality of light-emitting elements; the computer program causes the plurality of light-emitting elements to emit light sequentially at different light-emitting timings; causes each of the plurality of light-receiving elements to receive light that is emitted from the light-emitting element corresponding to each of the light-receiving elements and reflected back from the object to be measured; and performs processing related to the object to be measured based on the light-emitting timing of each of the corresponding light-emitting elements and the light-receiving timing of each of the light-receiving elements.

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