Electromagnetic wave irradiation device

Abstract

An electromagnetic wave irradiation device 1 comprises: an irradiation unit 10 that outputs an electromagnetic wave L1; a scanning unit 20 that changes an irradiation direction of the electromagnetic wave L1 in a plurality of different directions to output the electromagnetic wave L1 to a scanning area; a control unit 70 that controls the irradiation unit 10 and the scanning unit 20 to change the irradiation direction of the electromagnetic wave L1 and radiate the electromagnetic wave L1 a plurality of times in one cycle; and a detection unit 40 that detects a reflection wave L2 obtained by reflection of the electromagnetic wave L1 by a material body present in the scanning area, wherein the presence or absence or position of an object S to be detected in the scanning area is determined on the basis of first measurement information generated on the basis of the reflection wave L2 obtained by reflection of the electromagnetic wave L1 radiated a plurality of times during a partial period included in one cycle by the material body.

Description

Electromagnetic wave irradiation device CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to Japanese Patent Application No. 2023-213306, filed on December 18, 2023, the entire disclosure of which is incorporated herein by reference.

[0002] The present disclosure relates to an electromagnetic wave irradiation device.

[0003] In recent years, devices have been developed that acquire information about surrounding objects and the like from the results of detecting electromagnetic waves. For example, Patent Literature 1 discloses a LIDAR (Light Detection and Ranging, Laser Imaging Detection and Ranging) system that can reduce distortion of the illumination field.

[0004] Japanese Patent Application Laid-Open No. 2022-059924

[0005] An electromagnetic wave irradiation device according to a first aspect includes: an irradiation unit that outputs electromagnetic waves; a scanning unit that changes the irradiation direction of the electromagnetic waves in a plurality of different directions and outputs the electromagnetic waves to a scanning area; a control unit that controls the irradiation unit and the scanning unit to change the irradiation direction of the electromagnetic waves and irradiate the electromagnetic waves a plurality of times in one cycle; and a detection unit that detects reflected waves of the electromagnetic waves reflected by an object present in the scanning area. The electromagnetic wave irradiation device determines the presence or absence or position of an object to be detected in the scanning area based on first measurement information generated based on reflected waves of the electromagnetic waves reflected by the object, the electromagnetic waves being irradiated a plurality of times during a portion of the one cycle.

[0006] 1 is a block diagram showing a schematic configuration of an electromagnetic wave irradiation device according to an embodiment of the present disclosure. FIG. 1 is a schematic diagram showing a schematic configuration of the electromagnetic wave irradiation device of FIG. 1. FIG. 2 is a schematic diagram for explaining an example of the operation of a two-dimensional MEMS mirror of a scanning unit of FIG. 1. FIG. 3 is a flowchart showing an example of the operation of the electromagnetic wave irradiation device of FIG. 1. FIG. 4 is a schematic diagram for explaining an example of the operation of the electromagnetic wave irradiation device of FIG. 1. FIG. 5 is a diagram for explaining an example of the operation of the electromagnetic wave irradiation device of FIG. 1. FIG. 6 is a diagram for explaining an example of the operation of the electromagnetic wave irradiation device of FIG. 1. FIG. 7 is a diagram for explaining an example of the operation of the electromagnetic wave irradiation device of FIG. 1.

[0007] In the prior art, the detection accuracy when detecting an object using an electromagnetic wave irradiation device was not high.

[0008] According to an electromagnetic wave irradiation device according to an embodiment of the present disclosure, it is possible to improve the detection accuracy of an object.

[0009] Hereinafter, one embodiment of the present disclosure will be mainly described with reference to the accompanying drawings.

[0010] Fig. 1 is a block diagram showing a schematic configuration of an electromagnetic wave irradiation device 1 according to an embodiment of the present disclosure. Fig. 2 is a schematic diagram showing a schematic configuration of the electromagnetic wave irradiation device 1 of Fig. 1. An example of the configuration and functions of the electromagnetic wave irradiation device 1 according to an embodiment will be mainly described with reference to Figs. 1 and 2 .

[0011] 1 , an electromagnetic wave irradiation device 1 according to one embodiment includes an irradiation unit 10, a scanning unit 20, a switching unit 30, a detection unit 40, a sensor unit 50, a storage unit 60, and a control unit 70. The electromagnetic wave irradiation device 1 according to one embodiment may include all of these components, or may further include components other than these components, or may not include some of these components as long as the functions of the electromagnetic wave irradiation device 1 can be realized.

[0012] 1 and 2 may be communicably connected via wire or wirelessly to various other components that control and / or drive the respective components as appropriate. For example, the irradiation unit 10, the scanning unit 20, the switching unit 30, the detection unit 40, the sensor unit 50, and the storage unit 60 are communicably connected via wire or wirelessly to the control unit 70. The solid lines in Fig. 1 indicate control lines for controlling the respective components by the control unit 70.

[0013] Each component shown in Figures 1 and 2 may be connected to other components that supply power to the corresponding component, as appropriate. For ease of explanation, other components that supply power to the corresponding component are omitted from Figures 1 and 2. Each component shown in Figure 2 may be fixed and / or positioned at each position as shown in Figure 2, as appropriate. For ease of explanation, various members that fix and / or position each component are omitted from Figure 2.

[0014] As will be described in further detail below, the electromagnetic wave irradiation device 1 according to one embodiment irradiates electromagnetic waves and periodically changes the irradiation direction of the irradiated electromagnetic waves. At least a portion of the electromagnetic waves whose irradiation direction has been changed by the electromagnetic wave irradiation device 1 is reflected by a predetermined object or the like. The electromagnetic waves reflected by the predetermined object or the like are detected, for example, by the electromagnetic wave irradiation device 1. The electromagnetic wave irradiation device 1 according to one embodiment constitutes an information acquisition system. The information acquisition system includes, for example, a detection system and a ranging system for an object to be detected in a scanning area.

[0015] An information acquisition system according to one embodiment includes an electromagnetic wave irradiation device 1 and measures the distance to an object. The information acquisition system according to one embodiment employs, for example, LIDAR (Light Detection and Ranging, Laser Imaging Detection and Ranging) technology used in "light detection and ranging" or "laser imaging detection and ranging." The information acquisition system according to one embodiment can measure, for example, reflected light of pulsed laser irradiation light, and analyze the distance to an object located at a relatively long distance and / or the presence or absence of the object.

[0016] The irradiation unit 10 includes, for example, a laser diode (LD) such as a semiconductor laser that functions as a laser utilizing recombination light emission of a semiconductor. As will be described later with reference to FIG. 4 , the irradiation unit 10 may include, for example, a plurality of laser diodes arranged in an array in the electromagnetic wave irradiation device 1. The irradiation unit 10 irradiates, for example, a pulsed electromagnetic wave L1. The electromagnetic wave L1 is output so that the electromagnetic wave irradiation device 1 scans an object to be detected, measured, etc., and has, for example, a wavelength in the infrared region. The irradiation unit 10 irradiates the electromagnetic wave L1 toward the scanning unit 20. Therefore, the irradiation unit 10 is fixed and / or positioned so that the electromagnetic wave L1 irradiated by the irradiation unit 10 is incident on the scanning unit 20. The irradiation unit 10 outputs the electromagnetic wave L1 to a scanning area located outside the electromagnetic wave irradiation device 1 via the scanning unit 20.

[0017] The scanning unit 20 includes, for example, a reflecting mirror that changes (deflects) the irradiation direction of the incident electromagnetic wave L1. Reflecting mirrors include MEMS (Micro Electro Mechanical Systems) mirrors, polygon mirrors, galvanometer mirrors, and the like. Hereinafter, the reflecting mirror will be described as including a MEMS mirror. The scanning unit 20 periodically changes the irradiation direction of the electromagnetic wave L1 along a first direction D1 and a second direction D2 intersecting the first direction D1. The scanning unit 20 two-dimensionally scans the electromagnetic wave L1 irradiated by the irradiation unit 10. The scanning unit 20 includes a reflecting surface that oscillates around a first axis corresponding to scanning along the first direction D1 and a second axis intersecting (orthogonal to) the first axis and corresponding to scanning along the second direction D2. The two-dimensional MEMS mirror of the scanning unit 20 performs a resonant operation along the first direction D1 and a non-resonant operation along the second direction D2.

[0018] FIG. 3 is a schematic diagram illustrating an example of the operation of the two-dimensional MEMS mirror 21 of the scanning unit 20 in FIG. 1 . Here, for convenience, the first direction D1 and the second direction D2 are described in FIG. 3 as indicating a specific direction, but are not limited to such a description. The first direction D1 and the second direction D2 are directions in which the scanning unit 20 can change the irradiation direction of the electromagnetic wave L1, and do not necessarily indicate a specific direction. As an example, when the scanning area is depicted as a two-dimensional image, the first direction D1 may include the vertical direction, and the second direction D2 may include the horizontal direction. The vertical direction may correspond to at least one of the height direction and the depth direction in an actual three-dimensional space.

[0019] The two-dimensional MEMS mirror 21 of the scanning unit 20 oscillates at a resonant frequency around the first axis A1 as a rotation axis, thereby changing the orientation of the reflecting surface and changing the beam irradiation direction along the first direction D1. As an example, the two-dimensional MEMS mirror 21 changes the orientation of the reflecting surface along the first direction D1 from an angle θ1 to θ ｎ The two-dimensional MEMS mirror 21 changes the orientation of the reflecting surface by a predetermined angle by non-resonant driving with the second axis A2 as the rotation axis, thereby changing the beam irradiation direction along the second direction D2. As an example, the two-dimensional MEMS mirror 21 changes the orientation of the reflecting surface along the second direction D2 from an angle θ1 to θ ｍ It can be varied up to.

[0020] For convenience in Fig. 3, the first direction D1 may include a direction that is perpendicular to the first axis A1 and parallel to the second axis A2 in a two-dimensional plane including the first axis A1 and the second axis A2. As an example, the first direction D1 corresponds to the vertical direction in Fig. 3 for convenience. The second direction D2 may include a direction that is perpendicular to the second axis A2 and parallel to the first axis A1 in a two-dimensional plane including the first axis A1 and the second axis A2 for convenience in Fig. 3. As an example, the second direction D2 corresponds to the horizontal direction in Fig. 3 for convenience.

[0021] The two-dimensional MEMS mirror 21 of the scanning unit 20 has a predetermined rotation axis including a first axis A1 and a second axis A2, and rotates around the rotation axis. The rotation does not necessarily have to be an orbital motion, and may be, for example, an oscillating motion that includes a partial rotation of less than one revolution. The two-dimensional MEMS mirror 21 of the scanning unit 20 rotates to change the irradiation direction of the incident electromagnetic wave L1 toward the outside of the electromagnetic wave irradiation device 1. The scanning unit 20 is positioned so that the electromagnetic wave L1 emitted from the irradiation unit 10 is incident on the scanning unit 20, and the electromagnetic wave L1, the irradiation direction of which has been changed by the scanning unit 20, is emitted to the outside of the electromagnetic wave irradiation device 1.

[0022] The switching unit 30 has, for example, a DMD (Digital Micromirror Device). The DMD has an action surface onto which a reflected wave L2 is incident when the electromagnetic wave L1 is reflected by an object present in a scanning area located outside the electromagnetic wave irradiation device 1. The action surface is composed of a plurality of switching elements arranged two-dimensionally. The action surface is a surface that causes an optical effect, such as reflection or transmission, on the reflected wave L2 in at least one of a first state and a second state described below.

[0023] The switching unit 30 can switch, for each switching element, between a first state in which the reflected wave L2 incident on the action surface travels in a direction toward the detection unit 40 and a second state in which the reflected wave L2 travels in a direction away from the detection unit 40. More specifically, the switching unit 30 may include a reflective surface for each switching element that reflects the reflected wave L2. The switching unit 30 switches between the first state and the second state for each switching element by changing the orientation of the reflective surface for each switching element. The DMD of the switching unit 30 can drive tiny reflective surfaces that make up the action surface to switch the reflective surfaces for each switching element to an inclined state at either a first angle or a second angle with respect to the action surface. The action surface is, for example, parallel to the surface of a substrate on which the tiny reflective surfaces of the DMD are mounted.

[0024] The switching unit 30 switches between the first state and the second state for each switching element based on the control of the control unit 70. For example, the switching unit 30 simultaneously switches some of the switching elements to the first state to cause the reflected wave L2 incident on the switching element to travel in a direction toward the detection unit 40, and switches other of the switching elements to the second state to cause the reflected wave L2 incident on the switching element to travel in a direction away from the detection unit 40.

[0025] The detection unit 40 has, for example, a photodiode (PD), which is a semiconductor diode that functions as a photodetector. The PD includes, for example, an avalanche photodiode (APD). The detection unit 40 detects reflected waves L2 when the electromagnetic waves L1 are reflected by an object present in a scanning area located outside the electromagnetic wave irradiation device 1. The detection unit 40 is fixed and / or positioned so as to detect, as reflected waves L2, the electromagnetic waves L1 reflected by the object, among the electromagnetic waves L1 whose irradiation direction has been changed by the scanning unit 20.

[0026] The sensor unit 50 has, for example, a sensor element that detects the vibration state of the mobile object on which the electromagnetic wave irradiation device 1 is mounted. The sensor element includes a vibration sensor element, an acceleration sensor element, a speed sensor element, etc. The sensor unit 50 detects the vibration state of the mobile object on which the electromagnetic wave irradiation device 1 is mounted, and outputs detection information of the vibration state to the control unit 70.

[0027] The storage unit 60 has storage modules such as a hard disk drive (HDD), a solid state drive (SSD), an electrically erasable programmable read-only memory (EEPROM), a read-only memory (ROM), and a random access memory (RAM). The storage unit 60 stores information necessary to realize the operation of the electromagnetic wave irradiation device 1. The storage unit 60 stores information obtained by the operation of the electromagnetic wave irradiation device 1. For example, the storage unit 60 stores system programs, application programs, and various data acquired by any means such as communication.

[0028] The storage unit 60 may function as a main storage module, an auxiliary storage module, or a cache memory. The storage unit 60 is not limited to being built into the electromagnetic wave irradiation device 1, and may have an external storage module connected via a digital input / output port such as a USB (Universal Serial Bus).

[0029] The control unit 70 has, for example, a processor, a programmable circuit, a dedicated circuit, or any combination thereof. The processor includes a general-purpose processor such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit), or a dedicated processor specialized for specific processing. The programmable circuit includes an FPGA (Field-Programmable Gate Array), etc. The dedicated circuit includes an ASIC (Application Specific Integrated Circuit), etc. The control unit 70 is communicably connected to each component that makes up the electromagnetic wave irradiation device 1, and executes processing related to the operation of the electromagnetic wave irradiation device 1 while controlling each component.

[0030] 2, the electromagnetic wave irradiation device 1 has a first optical system S1 arranged on the irradiation side that irradiates the electromagnetic wave L1. The first optical system S1 has a first lens 80a and a second lens 80b in addition to the irradiation unit 10 and the scanning unit 20 described above.

[0031] The first lens 80a optically acts on the electromagnetic wave L1 irradiated from the irradiation unit 10. The first lens 80a includes a collimation lens that converts the electromagnetic wave L1 irradiated from the irradiation unit 10 into parallel light and guides it to the scanning unit 20. The first lens 80a is fixed and / or positioned so that the electromagnetic wave L1 from the irradiation unit 10 enters the first lens 80a and exits the first lens 80a to the scanning unit 20.

[0032] The second lens 80b optically acts on the electromagnetic wave L1 reflected by the scanning unit 20. The second lens 80b guides the electromagnetic wave L1 reflected by the scanning unit 20 to a scanning region located outside the electromagnetic wave irradiation device 1. The second lens 80b is fixed and / or positioned so that the electromagnetic wave L1 reflected by the scanning unit 20 enters the second lens 80b and exits it to the outside of the electromagnetic wave irradiation device 1.

[0033] The electromagnetic wave irradiation device 1 has a second optical system S2 arranged on the light receiving side for receiving a reflected wave L2 when the electromagnetic wave L1 is reflected by an object present in the scanning area. In addition to the switching unit 30 and the detection unit 40, the second optical system S2 has a third lens 80c and a fourth lens 80d.

[0034] The third lens 80c optically acts on the reflected wave L2 incident from a scanning region located outside the electromagnetic wave irradiation device 1. The third lens 80c guides the reflected wave L2 incident from the scanning region to the switching unit 30. The third lens 80c is fixed and / or positioned so that the reflected wave L2 is incident from outside the electromagnetic wave irradiation device 1 and is output to the switching unit 30.

[0035] The fourth lens 80d optically acts on the reflected wave L2 emitted in the direction from the switching unit 30 toward the detection unit 40. The fourth lens 80d includes a condenser lens that condenses the reflected wave L2 emitted in the direction from the switching unit 30 toward the detection unit 40 and guides it to the detection unit 40. The fourth lens 80d is fixed and / or positioned so that the reflected wave L2 from the switching unit 30 is incident on the fourth lens 80d and is emitted to the detection unit 40.

[0036] As described above, in the electromagnetic wave irradiation device 1, the electromagnetic wave L1 as infrared rays irradiated from the irradiation unit 10 is deflected by the scanning unit 20 and then emitted from the electromagnetic wave irradiation device 1. The electromagnetic wave irradiation device 1 scans objects and the like present around the electromagnetic wave irradiation device 1 using the electromagnetic wave L1.

[0037] Fig. 4 is a schematic diagram showing an example of the configuration of the irradiation unit 10 in Fig. 1. The irradiation unit 10 includes, for example, a first irradiation unit 11, a second irradiation unit 12, a third irradiation unit 13, and a fourth irradiation unit 14. The above description of the irradiation unit 10 similarly applies to each of the first irradiation unit 11, the second irradiation unit 12, the third irradiation unit 13, and the fourth irradiation unit 14. Each of the first irradiation unit 11, the second irradiation unit 12, the third irradiation unit 13, and the fourth irradiation unit 14 has an LD. The four LDs of the irradiation unit 10 are arranged, for example, in an array.

[0038] Each of the first irradiator 11, second irradiator 12, third irradiator 13, and fourth irradiator 14 included in the irradiator 10 is arranged, for example, so that the emission surface of the electromagnetic wave L1 faces the reflecting surface of the MEMS mirror of the scanner 20. For convenience, FIG. 4 illustrates a state in which the emission surface of the electromagnetic wave L1 faces downward and the electromagnetic wave L1 travels downward to the MEMS mirror of the scanner 20. The first irradiator 11, second irradiator 12, third irradiator 13, and fourth irradiator 14 included in the irradiator 10 are arranged, for example, in a line in a direction D2' along the first axis A1 of the MEMS mirror of the scanner 20, with the first irradiator 11, second irradiator 12, third irradiator 13, and fourth irradiator 14 arranged in order from one side to the other. The electromagnetic wave L1 travels, for example, along a direction D1' perpendicular to the direction D2'.

[0039] The control unit 70 of the electromagnetic wave irradiation device 1 turns the reflection surface of the two-dimensional MEMS mirror 21 to a predetermined direction, for example, an angle θ1, with the second axis A2 shown in FIG. 3 as the rotation axis. With the direction of the reflection surface around the second axis A2 as the rotation axis fixed, the control unit 70 turns the direction of the reflection surface around the first axis A1 as the rotation axis from angle θ1 to θ ｎ The irradiation unit 10 is caused to irradiate the electromagnetic wave L1 while changing the temperature from 100 to 1000.

[0040] When the irradiation unit 10 includes the first irradiation unit 11, the second irradiation unit 12, the third irradiation unit 13, and the fourth irradiation unit 14, the control unit 70 changes the orientation of the reflection surface about the first axis A1 as the rotation axis from angle θ1 to θ2 while fixing the orientation of the reflection surface about the second axis A2 as the rotation axis. ｎWhile changing the angle from 1 to 30°, the first irradiating unit 11 irradiates the electromagnetic wave L1, the second irradiating unit 12 irradiates the electromagnetic wave L1, the third irradiating unit 13 irradiates the electromagnetic wave L1, and the fourth irradiating unit 14 irradiates the electromagnetic wave L1 in turn for each angle. After the fourth irradiating unit 14 irradiates the electromagnetic wave L1 at one angle, the orientation of the reflecting surface with the first axis A1 as the rotation axis is changed to the next angle, and the angle θ ｎ The irradiation of the electromagnetic wave L1 is repeated for each angle, for example, in the order of the first irradiating unit 11, the second irradiating unit 12, the third irradiating unit 13, and the fourth irradiating unit 14, until the angle reaches the predetermined value.

[0041] Next, the control unit 70 changes the orientation of the reflecting surface by a predetermined angle around the second axis A2 as the rotation axis. The control unit 70 changes the orientation of the reflecting surface around the first axis A1 as the rotation axis from angle θ1 to θ2 while keeping the orientation of the reflecting surface around the second axis A2 as the rotation axis fixed. ｎ The control unit 70 performs the same operation as above. The control unit 70 performs the above operation while the orientation of the reflecting surface with the second axis A2 as the rotation axis is at an angle θ ｍ In the example shown below, the orientation of the reflecting surface around the second axis A2 as the rotation axis changes a total of eight times. As an example, m=8.

[0042] Fig. 5 is a flowchart showing an example of the operation of the electromagnetic wave irradiation device 1 of Fig. 1. With reference to Fig. 5, an example of a method for detecting an object executed by the electromagnetic wave irradiation device 1 of Fig. 1 will be mainly described.

[0043] In step S101, the control unit 70 of the electromagnetic wave irradiation device 1 determines the orientation of the two-dimensional MEMS mirror 21 of the scanning unit 20 along the second direction D2, that is, the orientation of the reflecting surface with the second axis A2 as the rotation axis.

[0044] In step S102, the control unit 70 of the electromagnetic wave irradiation device 1 determines the orientation of the two-dimensional MEMS mirror 21 of the scanning unit 20 along the first direction D1, that is, the orientation of the reflecting surface with the first axis A1 as the rotation axis.

[0045] In step S103, the control unit 70 of the electromagnetic wave irradiation device 1 controls the irradiation unit 10 to irradiate the electromagnetic wave L1 onto a scanning area located outside the electromagnetic wave irradiation device 1. Then, the control unit 70 of the electromagnetic wave irradiation device 1 controls the switching unit 30 and the detection unit 40 to detect a reflected wave L2 that is the electromagnetic wave L1 reflected by an object present in the scanning area.

[0046] In step S104, the control unit 70 of the electromagnetic wave irradiation device 1 determines whether the first irradiating unit 11, the second irradiating unit 12, the third irradiating unit 13, and the fourth irradiating unit 14 have irradiated the electromagnetic waves L1 in all irradiation directions along the first direction D1, while the orientation of the two-dimensional MEMS mirror 21 along the second direction D2 is fixed. If the control unit 70 determines that the electromagnetic waves L1 have been irradiated in all irradiation directions along the first direction D1, it executes the process of step S105. If the control unit 70 determines that the electromagnetic waves L1 have not been irradiated in all irradiation directions along the first direction D1, it executes the process of step S102 again.

[0047] In step S105, the control unit 70 of the electromagnetic wave irradiation device 1 generates first measurement information based on reflected waves L2 that are reflected by an object when electromagnetic waves L1 are irradiated multiple times while being changed along the first direction D1 in some of multiple predetermined directions in the second direction D2.

[0048] In step S106, the control unit 70 of the electromagnetic wave irradiation device 1 determines whether the electromagnetic waves L1 have been irradiated in all of the plurality of predetermined directions. If the control unit 70 determines that the electromagnetic waves L1 have been irradiated in all of the plurality of predetermined directions, it executes the process of step S107. If the control unit 70 determines that the electromagnetic waves L1 have not been irradiated in all of the plurality of predetermined directions, it executes the process of step S101 again. In the example shown below, as an example, the number of the plurality of predetermined directions is eight. The number of the plurality of predetermined directions is set based on the number of directions (e.g., eight) in which the two-dimensional MEMS mirror 21 changes the reflecting surface around the second axis A2 as the rotation axis.

[0049] In step S107, the control unit 70 of the electromagnetic wave irradiation device 1 generates second measurement information based on the plurality of pieces of first measurement information generated in step S105.

[0050] As described above, the control unit 70 radiates the electromagnetic wave L1 multiple times in multiple predetermined directions in the second direction D2 by changing the radiation direction of the electromagnetic wave L1 along the first direction D1. The control unit 70 generates first measurement information based on reflected waves L2 formed by the electromagnetic wave L1 radiated multiple times in some of the multiple predetermined directions while changing the radiation direction along the first direction D1 and reflected by an object. The control unit 70 generates other first measurement information based on reflected waves L2 formed by the electromagnetic wave L1 radiated multiple times in other of the multiple predetermined directions while changing the radiation direction along the first direction D1 and reflected by an object. The control unit 70 further generates second measurement information based on the generated multiple pieces of first measurement information.

[0051] The series of processes performed by the control unit 70 of the electromagnetic wave irradiation device 1 will be described in more detail below.

[0052] Fig. 6 is a first diagram for explaining an example of the operation of the electromagnetic wave irradiation device 1 of Fig. 1. Fig. 6 shows an example of measurement information generated by the control unit 70 collectively using information on reflected waves L2 that are formed by reflecting electromagnetic waves L1 that are irradiated in all of a plurality of predetermined directions in the second direction D2 from an object. In the example shown in Fig. 6, the object includes only the road surface.

[0053] Each point indicates a reflection point on an object of the electromagnetic wave L1 output from the electromagnetic wave irradiation device 1. The multiple points P1 shown at the lightest level indicate that the reflection points were detected as being located on the same plane. The multiple points P3 shown at the darkest level indicate that the reflection points were detected as being located above the plane indicated by the multiple points P1. The multiple points P2 shown darker than point P1 and lighter than point P3 indicate that the reflection points were detected as being located below the plane indicated by the multiple points P1. The range of the point cloud shown in Figure 6 corresponds to the scanning area located outside the electromagnetic wave irradiation device 1.

[0054] The control unit 70 of the electromagnetic wave irradiation device 1 uses the irradiation unit 10 and the scanning unit 20 to irradiate the electromagnetic wave L1 multiple times in multiple predetermined directions, e.g., eight directions, along the second direction D2 by changing the irradiation direction of the electromagnetic wave L1 along the first direction D1. For convenience, in FIG. 6 , the first direction D1 is a direction perpendicular to the depth direction D3 and the second direction D2 in the scanning area, and the second direction D2 is a horizontal direction in the scanning area. In each predetermined direction along the second direction D2, multiple points are obtained arranged on a line along the depth direction D3. The control unit 70 completes scanning of the object by acquiring point cloud data located on each of, for example, 32 lines in the second direction D2.

[0055] For example, the control unit 70 acquires point cloud data for 8 lines located on one side of the second direction D2 out of 32 lines in the second direction D2 by using the first irradiating unit 11 and the scanning unit 20. The control unit 70 similarly acquires point cloud data for 8 lines adjacent to the 8 lines illuminated by the first irradiating unit 11 out of 32 lines in the second direction D2 by using the second irradiating unit 12 and the scanning unit 20.

[0056] For example, the control unit 70 uses the third irradiation unit 13 and the scanning unit 20 to similarly acquire point cloud data for eight lines, of the 32 lines in the second direction D2, that are adjacent to the eight lines illuminated by the second irradiation unit 12. The control unit 70 uses the fourth irradiation unit 14 and the scanning unit 20 to acquire point cloud data for eight lines, of the 32 lines in the second direction D2, that are located on the other side of the second direction D2.

[0057] Fig. 7 is a second diagram for explaining an example of the operation of the electromagnetic wave irradiation device 1 of Fig. 1. Fig. 7 shows the irradiation order of the irradiation unit 10 for the first irradiation unit 11, the second irradiation unit 12, the third irradiation unit 13, and the fourth irradiation unit 14 when the direction of the reflecting surface of the two-dimensional MEMS mirror 21 in the second direction D2 is fixed and point cloud data is acquired for every four lines out of 32 lines while the control unit 70 controls the irradiation unit 10 and the scanning unit 20. In the "irradiation order" item of the table in Fig. 7B, for example, when the direction of the reflecting surface of the two-dimensional MEMS mirror 21 in the second direction D2 is θ１ From θ ｍ 7B, the order of irradiation of the electromagnetic wave L1 by the first irradiating unit 11, the second irradiating unit 12, the third irradiating unit 13, and the fourth irradiating unit 14 is assigned. In the "irradiating unit" item of the table in FIG. 7B, the corresponding irradiating unit 10 among the first irradiating unit 11, the second irradiating unit 12, the third irradiating unit 13, and the fourth irradiating unit 14 is shown.

[0058] For example, the control unit 70 controls the electromagnetic wave L1 to be emitted in a plurality of predetermined directions in the second direction D2, i.e., eight directions, at different timings for each of the directions. For example, the control unit 70 controls the orientation of the reflecting surface of the two-dimensional MEMS mirror 21 in the second direction D2 by θ １ With the position fixed, the first irradiating unit 11 first irradiates one point on the line 1 with the electromagnetic waves L1 using the first irradiating unit 11, the second irradiating unit 12 second irradiates one point on the line 1 with the electromagnetic waves L1 using the second irradiating unit 12, the third irradiating unit 13 third irradiates one point on the line 1 with the electromagnetic waves L1 using the third irradiating unit 13, and the fourth irradiating unit 14 fourth irradiates one point on the line 1 with the electromagnetic waves L1 using the fourth irradiating unit 14. The control unit 70 then repeats the irradiation of the electromagnetic waves L1 in the order of the first irradiating unit 11, the second irradiating unit 12, the third irradiating unit 13, and the fourth irradiating unit 14 until the direction of the electromagnetic waves L1 has been changed along the first direction D1. As a result, the control unit 70 acquires point cloud data for line 1 of the first irradiation unit 11, point cloud data for line 1 of the second irradiation unit 12, point cloud data for line 1 of the third irradiation unit 13, and point cloud data for line 1 of the fourth irradiation unit 14.

[0059] Similarly, the control unit 70 adjusts the orientation of the reflecting surface of the two-dimensional MEMS mirror 21 in the second direction D2 by θ ｍThe first irradiation unit 11, the second irradiation unit 12, the third irradiation unit 13, and the fourth irradiation unit 14 are periodically and repeatedly used while changing the direction of irradiation up to line 8 (m = 8) of the first irradiation unit 11, the second irradiation unit 12, the third irradiation unit 13, and the fourth irradiation unit 14, while changing the direction of irradiation in eight directions in the second direction D2, until point cloud data for 32 lines up to line 8 (m = 8) of the first irradiation unit 11, the second irradiation unit 12, the third irradiation unit 13, and the fourth irradiation unit 14 are acquired. The same drawing as in FIG. 7A is arranged in FIG. 6, and numbers corresponding to the order listed in the "second direction (1 to m)" in the table in FIG. 7B are added. The kth listed in the "irradiation order" indicates that the kth irradiation is performed in each of the second directions (1 to m).

[0060] The plurality of point cloud data acquired in the above acquisition order corresponds to measurement information generated by the control unit 70 using information on the reflected wave L2 collectively. The control unit 70 generates measurement information such as that shown in FIG. 6 using a statistical method such as RANSAC (Random Sample Consensus). The control unit 70 estimates a plane (road surface) from the plurality of point cloud data by performing RANSAC. The control unit 70 then classifies each point included in the plurality of point cloud data as either a point located on the same plane as the estimated plane or a point not located on the same plane. In other words, the plurality of points P1, P2, and P3 shown in FIG. 6 are the result of the control unit 70 classifying point P1 as a point located on the same plane as the estimated plane and points P2 and P3 as points not located on the same plane as the estimated plane. In this case, as shown in FIG. 6, when all 32 lines are processed collectively as one scan, many points P2 and P3 are found to be located at positions different from the plane indicated by the multiple points P1.

[0061] The electromagnetic wave irradiation device 1 does not accurately detect the road surface as a single plane, for example, due to vibrations of the mobile body on which the electromagnetic wave irradiation device 1 is mounted. Ideally, all points would be shown as point P1 in the measurement information shown in Fig. 6, but points P2 and P3 are included as errors due to vibrations of the mobile body on which the electromagnetic wave irradiation device 1 is mounted.

[0062] FIG. 8 is a schematic diagram for explaining factors that cause errors in the measurement information shown in FIG.

[0063] The electromagnetic wave irradiation device 1 mounted on a mobile object changes the position and orientation of the emission port from which the electromagnetic waves L1 are emitted from the electromagnetic wave irradiation device 1, as well as the position of the entire device in three-dimensional coordinates in space, due to vibrations of the mobile object, etc. For example, assume that the electromagnetic wave irradiation device 1 is in the position and orientation shown by the solid line in Figure 8 when not affected by vibrations of the mobile object, etc. For example, the electromagnetic wave irradiation device 1 may change its position and orientation vertically upward from this state due to influences such as vibrations of the mobile object, etc. For example, the electromagnetic wave irradiation device 1 may change its position and orientation vertically downward from this state due to influences such as vibrations of the mobile object, etc.

[0064] For example, suppose the electromagnetic wave irradiation device 1 detects an ideal plane in which all points are represented by point P1, without being affected by vibrations of the moving object. In this case, if the height of the electromagnetic wave irradiation device 1 from the road surface and the direction of the outlet from which the electromagnetic wave L1 is emitted from the electromagnetic wave irradiation device 1 change upward, the electromagnetic wave irradiation device 1 acquires data on a cloud of points in an upward deflection state. As a result, the measurement information is likely to include point P3 as an error, as the reflection point is located above the plane represented by the multiple points P1. Conversely, if the height of the electromagnetic wave irradiation device 1 from the road surface and the direction of the outlet from which the electromagnetic wave L1 is emitted from the electromagnetic wave irradiation device 1 change downward, the electromagnetic wave irradiation device 1 acquires data on a cloud of points in a downward deflection state. As a result, the measurement information is likely to include point P2 as an error, as the reflection point is located below the plane represented by the multiple points P1.

[0065] When the control unit 70 of the electromagnetic wave irradiation device 1 performs RANSAC processing while being affected by the vibrations of the moving body as described above, it is possible that it may mistakenly detect that the road surface is not a road surface or that there are unevenness in the road surface.

[0066] In one embodiment, the control unit 70 of the electromagnetic wave irradiation device 1 does not process all 32 lines acquired in one cycle shown in Fig. 6 as one scan in order to obtain more ideal measurement information. In other words, the control unit 70 generates first measurement information based on reflected waves L2 that are generated by reflecting electromagnetic waves L1 that are irradiated during a partial period included in one cycle and are reflected by an object. One cycle includes, for example, multiple partial periods. The control unit 70 generates first measurement information for each of the partial periods.

[0067] The control unit 70 generates first measurement information based on reflected waves L2 of the irradiated electromagnetic waves L1 reflected by an object during a period in which the electromagnetic waves L1 are irradiated in some of eight predetermined directions along the second direction D2. The control unit 70 generates the first measurement information using a statistical method such as RANSAC for each of four consecutive subscans in which the electromagnetic waves L1 are irradiated. By generating the first measurement information for each of four consecutive subscans in which the electromagnetic waves L1 are irradiated, the time required for irradiating the electromagnetic waves L1 can be shortened and the effects of vibration can be suppressed. For example, by performing four subscans in a state in which the vehicle is overexcited or underexcited due to the effects of vibration, a statistical method such as RANSAC can be used on the multiple point cloud data acquired only in the overexcited or underexcited state. For example, in the case of an overexcited state, the road surface can be estimated using only the multiple points P3 shown in FIG. 8 , whereas in the case of a underexcited state, the road surface can be estimated using only the multiple points P2 shown in FIG. 8 .

[0068] Therefore, the first measurement information includes the three-dimensional spatial coordinates of each point included in the plurality of point cloud data and a classification result indicating whether the point is located on the same plane as the plane estimated by RANSAC or not. The first measurement information may be used to determine the presence or location of an object to be detected in the scanning area. The control unit 70 may determine the presence or location of an object to be detected in the scanning area based on the generated first measurement information. The control unit 70 generates second measurement information based on multiple pieces of first measurement information generated over multiple partial periods. The control unit 70 generates second measurement information corresponding to the measurement information of FIG. 6 by overlaying, for example, eight pieces of first measurement information obtained by sub-scanning every four lines. The object to be detected may be, for example, any object fallen on the road surface, a pedestrian on the road surface, another moving object, etc. One or multiple objects may be set as the object to be detected.

[0069] The control unit 70 may use the second measurement information to determine the presence or position of an object in the scanning area. For example, the control unit 70 may determine the presence or position of an object to be detected in the scanning area based on second measurement information generated from multiple pieces of first measurement information. The control unit 70 may generate the second measurement information as information used to display measurement results on an information processing device equipped with an external display. When generating the second measurement information, the control unit 70 may correct the three-dimensional coordinates of the reflection points included in each piece of first measurement information based on the three-dimensional coordinates in space of the reflection points divided as road surfaces in each piece of first measurement information. The control unit 70 may correct the coordinates of each point that is assumed to be on the same plane in each piece of first measurement information to position them on a single plane, and then generate integrated second measurement information. The control unit 70 may generate second measurement information for each piece of first measurement information. For example, if the control unit 70 wants to determine the presence or position of an object to be detected only in a specific irradiation direction, it may generate second measurement information from one piece of first measurement information generated by irradiating electromagnetic wave L1 in the corresponding direction.

[0070] Fig. 9 is a third diagram for explaining an example of the operation of the electromagnetic wave irradiation device 1 of Fig. 1. Fig. 9 is a schematic diagram showing an example of four-line sub-scanning by the control unit 70. The four lines shown in Fig. 9 correspond to line 1 of the first irradiating unit 11, line 1 of the second irradiating unit 12, line 1 of the third irradiating unit 13, and line 1 of the fourth irradiating unit 14, in that order from one side of the second direction D2.

[0071] Some of the plurality of predetermined directions in the second direction D2 include a first orientation in the second direction D2 and a second orientation different from the first orientation. For example, in Fig. 9 , the first orientation includes one orientation of line 1 of the first irradiating unit 11, line 1 of the second irradiating unit 12, line 1 of the third irradiating unit 13, and line 1 of the fourth irradiating unit 14. The second orientation includes another orientation of line 1 of the first irradiating unit 11, line 1 of the second irradiating unit 12, line 1 of the third irradiating unit 13, and line 1 of the fourth irradiating unit 14.

[0072] The control unit 70 causes the electromagnetic waves L1 to be emitted at different timings in the first direction and the second direction. For example, the control unit 70 repeatedly causes the first irradiating unit 11, the second irradiating unit 12, the third irradiating unit 13, and the fourth irradiating unit 14 to emit the electromagnetic waves L1 at different timings in each direction in this order. In this way, the control unit 70 acquires point cloud data for each line.

[0073] 9 , the control unit 70 determines a part of the direction along the second direction D2, i.e., the irradiation direction of the electromagnetic wave L1, and then acquires point cloud data for line 1 of the first irradiating unit 11, line 1 of the second irradiating unit 12, line 1 of the third irradiating unit 13, and line 1 of the fourth irradiating unit 14 while controlling the first irradiating unit 11, the second irradiating unit 12, the third irradiating unit 13, and the fourth irradiating unit 14. The control unit 70 generates first measurement information based on the acquired plurality of point cloud data using a statistical method such as RANSAC.

[0074] The control unit 70 also performs similar processing on each of lines 2, 3, 4, 5, 6, 7, and 8 of each of the irradiation units 10 including the first irradiation unit 11, the second irradiation unit 12, the third irradiation unit 13, and the fourth irradiation unit 14. Some of the plurality of predetermined directions in the second direction D2 further include a first orientation, a second orientation, a third orientation, and a fourth orientation that are different from one another in the second direction D2.

[0075] For example, the first orientation includes one orientation of one of lines 1, 2, 3, 4, 5, 6, 7, and 8 of each irradiation unit 10. The third orientation includes another orientation of the one line. The second orientation includes one orientation of another of lines 1, 2, 3, 4, 5, 6, 7, and 8 of each irradiation unit 10. The fourth orientation includes another orientation of the other lines.

[0076] For example, the first orientation includes one orientation of line 1 of each irradiation unit 10. The third orientation includes another orientation of line 1 of each irradiation unit 10. In this case, the second orientation includes, for example, one orientation of line 2 of each irradiation unit 10. The fourth orientation includes, for example, the other orientation of line 2 of each irradiation unit 10.

[0077] For example, the first direction includes line 1 of the first irradiating unit 11, and the second direction includes line 2 of the first irradiating unit 11. The first irradiating unit 11 outputs electromagnetic waves L1 to be irradiated in the first and second directions. For example, the third direction includes line 1 of the second irradiating unit 12, and the fourth direction includes line 2 of the second irradiating unit 12. The second irradiating unit 12 outputs electromagnetic waves L1 to be irradiated in the third and fourth directions.

[0078] In the second direction D2, the distance between the first orientation and the third orientation is the same as the distance between the second orientation and the fourth orientation. For example, the distance in the second direction D2 between line 1 of the first irradiating unit 11 and line 1 of the second irradiating unit 12 is the same as the distance in the second direction D2 between line 2 of the first irradiating unit 11 and line 2 of the second irradiating unit 12.

[0079] The control unit 70 sets a partial direction in the second direction D2 and then repeatedly irradiates the electromagnetic wave L1 in the first direction and then the third direction while changing the direction along the first direction D1. Next, the control unit 70 sets another partial direction in the second direction D2 and then repeatedly irradiates the electromagnetic wave L1 in the second direction and then the fourth direction while changing the direction along the first direction D1. The control unit 70 generates first measurement information based on reflected waves L2 that are reflected by an object from the electromagnetic wave L1 that has been irradiated multiple times while changing the direction along the first direction D1 in the first and third directions. For example, the control unit 70 generates first measurement information for line 1 of the four irradiating units 10. The control unit 70 generates different first measurement information based on reflected waves L2 that are reflected by an object from the electromagnetic wave L1 that has been irradiated multiple times while changing the direction along the first direction D1 in the second and fourth directions. For example, the control unit 70 generates different first measurement information for line 2 of the four irradiating units 10.

[0080] Fig. 10 is a fourth diagram for explaining an example of the operation of the electromagnetic wave irradiation device 1 of Fig. 1. Fig. 10 shows first measurement information based on four sub-scanning lines, generated by the control unit 70 of the electromagnetic wave irradiation device 1.

[0081] As shown by the multiple points P1 in Fig. 10, multiple reflection points located on the same plane are detected with high accuracy. The multiple points P1 represent, for example, the road surface of the object. Meanwhile, multiple reflection points located above the plane represented by the multiple points P1 are detected as multiple points P3 on the far side in the depth direction D3. The multiple points P3 represent, for example, a fence and a tree installed on the road surface of the object.

[0082] Fig. 11 is a fifth diagram for explaining an example of the operation of the electromagnetic wave irradiation device 1 of Fig. 1. Fig. 11 shows second measurement information generated by the control unit 70 of the electromagnetic wave irradiation device 1 using a plurality of pieces of first measurement information as shown in Fig. 10.

[0083] The control unit 70 generates second measurement information as shown in FIG. 11 by superimposing multiple pieces of first measurement information as shown in FIG. 10. As shown in FIG. 11, points P2 and P3 are partially acquired within the range of the road surface as the target object, but multiple other points P1 accurately detect multiple reflection points located within the same plane. As in FIG. 10, the multiple points P1 represent, for example, the road surface of the object. Meanwhile, multiple reflection points located above the plane represented by the multiple points P1 are detected as multiple points P3 on the far side in the depth direction D3. As in FIG. 10, the multiple points P3 represent, for example, a fence and a tree installed on the road surface as an object.

[0084] Fig. 12 is a sixth diagram for explaining an example of the operation of the electromagnetic wave irradiation device 1 of Fig. 1. Fig. 13 is a seventh diagram for explaining an example of the operation of the electromagnetic wave irradiation device 1 of Fig. 1. The control unit 70 of the electromagnetic wave irradiation device 1 detects the road surface and the target object S located on the road surface, which are included in the object, by distinguishing them from each other based on the first measurement information or the second measurement information. The target object S includes any fallen object that has fallen on the road surface. Such detection processing will be mainly explained with reference to Figs. 12 and 13.

[0085] Fig. 12 shows second measurement information generated by the control unit 70 based on multiple sub-scans, while Fig. 13 shows measurement information generated by the control unit 70 collectively using information on reflected waves L2 that are generated by an object after irradiating electromagnetic waves L1 in all of multiple predetermined directions in the second direction D2.

[0086] 13, which was generated without using subscanning, the road surface and an object S located on the road surface are detected. However, many points P3 other than the object S are acquired as noise around the object S. This makes it difficult to clearly distinguish between the object S located on the road surface and the noise, reducing the detection accuracy of the object S located on the road surface.

[0087] On the other hand, the second measurement information shown in Fig. 12, which was generated using a subscan, also detects the road surface and the object S located on the road surface. Unlike the measurement information shown in Fig. 13, almost no points P3 other than the object S are acquired around the object S. This makes it clearer to distinguish between the object S located on the road surface and noise, improving the detection accuracy of the object S located on the road surface.

[0088] In addition to the above-described processing, the control unit 70 of the electromagnetic wave irradiation device 1 may determine the length of the partial period according to the information on the vibration state detected by the sensor unit 50. The control unit 70 may also determine the number of partial directions among the plurality of predetermined directions in the second direction D2 to which the electromagnetic waves L1 are irradiated during the partial period. In the above embodiment, the number of predetermined directions is eight, and the number of partial directions is one, but this is not limited to this, and the number may be variable according to the information on the vibration state detected by the sensor unit 50.

[0089] For example, if the vibration of the mobile body on which the electromagnetic wave irradiation device 1 is mounted is large, the control unit 70 may set the number of directions to be reduced in some directions. Large vibration of the mobile body means that at least one of the numerical values ​​indicating the amplitude and frequency of the vibration is large.

[0090] For example, if the number of the partial directions is set to two and the amplitude of the vibration of the moving body is large, the position of the emission port from which the electromagnetic waves L1 are emitted from the electromagnetic wave irradiation device 1 and the position on the three-dimensional coordinate system in space of the electromagnetic wave irradiation device 1 will be significantly different between the first time the electromagnetic waves L1 are emitted in one of the partial directions and the last time the electromagnetic waves L1 are emitted. Therefore, if the first measurement information is generated based on the two set directions, the road surface cannot be accurately detected due to the influence of the vibration, and the detection accuracy of the object S will be reduced.

[0091] For example, if the number of some directions is set to two and the frequency of vibration of the moving body is high, the position of the emission port from which the electromagnetic waves L1 are emitted from the electromagnetic wave irradiation device 1 and the position on the three-dimensional coordinate system in space of the electromagnetic wave irradiation device 1 will change in a short period. Therefore, if the first measurement information is generated based on the two set directions, the road surface cannot be accurately detected due to the influence of the vibration, and the detection accuracy of the object S will decrease.

[0092] Therefore, the control unit 70 may predict the vibration state of the moving body according to detection information of the vibration state detected by the sensor unit 50, and may set the number of some directions by calculating, based on the predicted vibration state, the number of some directions to which the electromagnetic waves L1 can be irradiated during a period in which the displacement amount of the position on the three-dimensional coordinate in space of the electromagnetic wave irradiation device 1 and the emission port from which the electromagnetic waves L1 are emitted from the electromagnetic wave irradiation device 1 falls within a predetermined range. The control unit 70 may predict a displacement based on the vibration state of the electromagnetic wave irradiation device 1 based on the detection information, and may determine the number of directions to which the electromagnetic waves L1 can be irradiated during a period in which the displacement amount of the electromagnetic wave irradiation device 1 falls within a predetermined range as the number of some directions.

[0093] As a result, the control unit 70 can reduce the tendency for errors at points P2 and P3 to occur frequently due to large vibrations of the moving body.

[0094] Conversely, if the vibration of the mobile body on which the electromagnetic wave irradiation device 1 is mounted is small, the control unit 70 may set the number of some directions to be more than 1. Small vibration of the mobile body means that at least one of the numerical values ​​indicating the amplitude and frequency of the vibration is small. In this case, increasing the number of some directions reduces the amount of first measurement information, but can increase the amount of information included in one piece of first measurement information, thereby improving the accuracy of road surface detection.

[0095] Therefore, in this case as well, similar to the processing performed when the vibration of the moving body is large, the control unit 70 may predict the vibration state of the moving body according to the detection information of the vibration state detected by the sensor unit 50, and may set the number of some directions by calculating, based on the predicted vibration state, the number of some directions to which the electromagnetic waves L1 can be irradiated during a period in which the displacement amount of the position on the three-dimensional coordinate system in space of the electromagnetic wave irradiation device 1 and the emission port from which the electromagnetic waves L1 are emitted from the electromagnetic wave irradiation device 1 falls within a predetermined range. The control unit 70 may predict a displacement based on the vibration state of the electromagnetic wave irradiation device 1 based on the detection information, and may determine the number of directions to which the electromagnetic waves L1 can be irradiated during a period in which the displacement amount of the electromagnetic wave irradiation device 1 falls within a predetermined range as the number of some directions.

[0096] The control unit 70 may determine the length of the partial period determined according to the vibration state based on the number of directions (the number of lines) in which the electromagnetic waves L1 are emitted, rather than the number of partial directions among the plurality of predetermined directions in the second direction D2. In this case, when the vibration of the moving body is large, the number of directions (the number of lines) in which the electromagnetic waves L1 are emitted in the partial period may be set to be, for example, less than four directions included in the partial directions, whereas when the vibration of the moving body is small, the number of directions (the number of lines) in which the electromagnetic waves L1 are emitted in the partial period may be set to be, for example, more than four directions included in the partial directions.

[0097] As a result, the control unit 70 can increase the population of point cloud data that is the subject of statistical processing such as RANSAC, while errors such as points P2 and P3 tend not to occur frequently due to small vibrations of the moving body.

[0098] The electromagnetic wave irradiation device 1 according to the embodiment described above can improve the detection accuracy of the target object S. The electromagnetic wave irradiation device 1 generates first measurement information based on reflected waves L2 that are generated when electromagnetic waves L1 are irradiated in some of a plurality of predetermined directions in the second direction D2 and reflected by an object. The electromagnetic wave irradiation device 1 determines the presence or absence or position of the target object S to be detected in the scanning area based on the generated first measurement information.

[0099] This allows the electromagnetic wave irradiation device 1 to perform statistical processing such as RANSAC for each sub-scan. The electromagnetic wave irradiation device 1 can reduce the probability of errors such as outliers occurring by reducing the population of point cloud data that is the subject of statistical processing. The electromagnetic wave irradiation device 1 can improve the detection accuracy of the target object S while reducing the influence of vibrations of the mobile object on which the electromagnetic wave irradiation device 1 is mounted.

[0100] The electromagnetic wave irradiation device 1 generates second measurement information relating to the presence or absence or position of the object S in the scanning area based on the generated plurality of pieces of first measurement information. This allows the electromagnetic wave irradiation device 1 to perform statistical processing such as RANSAC for each sub-scan. The electromagnetic wave irradiation device 1 can reduce the probability of errors such as outliers occurring by reducing the population of point cloud data that is the subject of statistical processing. The electromagnetic wave irradiation device 1 can improve the detection accuracy of the object S while reducing the influence of vibrations of the mobile object on which the electromagnetic wave irradiation device 1 is mounted.

[0101] For example, the measurement information shown in FIG. 6 , which was acquired without using subscanning, is compared with the second measurement information shown in FIG. 11 , which was acquired using subscanning. In this case, the number of points P2 and P3 obtained as noise in the road surface area of ​​the object is smaller in the second measurement information shown in FIG. 11 than in the measurement information shown in FIG. 6 . Therefore, the electromagnetic wave irradiation device 1 can improve the detection accuracy of planar road surfaces. Similarly, as described above with reference to FIGS. 12 and 13 , the electromagnetic wave irradiation device 1 can clearly distinguish between an object S located on the road surface and noise, thereby improving the detection accuracy of an object S located on the road surface.

[0102] The electromagnetic wave irradiation device 1 can precisely perform sub-scanning for each of a plurality of predetermined directions in the second direction D2 by irradiating the electromagnetic waves L1 at different timings in a first direction and a second direction that are included in a portion of the second direction D2. For example, the electromagnetic wave irradiation device 1 can precisely perform sub-scanning for each of a plurality of lines in the scanning area.

[0103] The electromagnetic wave irradiation device 1 generates first measurement information based on reflected waves L2 that are formed by the electromagnetic waves L1 being irradiated multiple times along the first direction D1 while being changed in a first orientation and a third orientation that are included in a portion of the second direction D2, and reflected by an object. The electromagnetic wave irradiation device 1 generates different first measurement information based on reflected waves L2 that are formed by the electromagnetic waves L1 being irradiated multiple times along the first direction D1 while being changed in a second orientation and a fourth orientation that are included in a portion of the second direction D2, and reflected by an object. This allows the electromagnetic wave irradiation device 1 to perform sub-scans on some of the multiple lines in the scanning area, thereby reducing errors such as outliers in statistical processing such as RANSAC.

[0104] In the second direction D2, the distance between the first orientation and the third orientation, which are included in a part of the second direction D2, and the distance between the second orientation and the fourth orientation, which are included in a part of the second direction D2, are the same, so that the electromagnetic wave irradiation device 1 can widen the area scanned by each subscan. For example, as shown in FIG. 9 , the scanning area is widened by a subscan by the electromagnetic wave irradiation device 1 using line 1 of each irradiation unit 10. Similarly, the scanning area is widened by a subscan by the electromagnetic wave irradiation device 1 using line 2 of each irradiation unit 10. The same applies to subscans by the electromagnetic wave irradiation device 1 using other lines of each irradiation unit 10.

[0105] The irradiation unit 10 has a first irradiation unit that outputs a first electromagnetic wave L1 that is irradiated in a first direction and a second direction that are included in a part of the second direction D2, and a second irradiation unit that outputs a second electromagnetic wave L1 that is irradiated in a third direction and a fourth direction that are included in a part of the second direction D2. The first irradiation unit includes one irradiation unit 10 among the first irradiation unit 11, the second irradiation unit 12, the third irradiation unit 13, and the fourth irradiating unit 14. The second irradiation unit includes the other irradiation unit 10 among the first irradiating unit 11, the second irradiating unit 12, the third irradiating unit 13, and the fourth irradiating unit 14.

[0106] This allows the electromagnetic wave irradiation device 1 to easily expand the entire scanning area by using multiple irradiation units 10. For example, the electromagnetic wave irradiation device 1 can also expand the area where 32 lines exist in the second direction D2. The electromagnetic wave irradiation device 1 can perform detection processing of the object S in a wide scanning area.

[0107] The electromagnetic wave irradiation device 1 determines the length of the partial period according to the information on the vibration state detected by the sensor unit 50, thereby optimizing the number of partial directions according to the vibration state of the mobile object on which the electromagnetic wave irradiation device 1 is mounted. This allows the electromagnetic wave irradiation device 1 to reduce the tendency for many errors such as points P2 and P3 to occur due to large vibrations of the mobile object. Conversely, the electromagnetic wave irradiation device 1 can also increase the population of point cloud data that is the subject of statistical processing such as RANSAC, even when there is a tendency for many errors such as points P2 and P3 to occur due to small vibrations of the mobile object.

[0108] The electromagnetic wave irradiation device 1 predicts a displacement based on the vibration state of the electromagnetic wave irradiation device 1 based on the detection information, and determines the number of directions in which the electromagnetic waves L1 can be irradiated during a period in which the amount of displacement of the electromagnetic wave irradiation device 1 falls within a predetermined range. This allows the electromagnetic wave irradiation device 1 to further optimize the number of directions in accordance with the vibration state of the mobile object on which the electromagnetic wave irradiation device 1 is mounted.

[0109] The electromagnetic wave irradiation device 1 detects the road surface and the target object S located on the road surface, which are included in the object, by distinguishing them from each other based on the second measurement information, and can accurately identify, for example, an object that has fallen on the road surface as the target object S. This type of discrimination process by the electromagnetic wave irradiation device 1 makes it possible for a mobile body equipped with the electromagnetic wave irradiation device 1 to perform automatic driving so as to avoid the target object S, or to output driving instructions to avoid the target object S and assist the driver in driving.

[0110] It will be apparent to those skilled in the art that the present disclosure may be embodied in other specific forms other than the above-described embodiments without departing from the spirit or essential characteristics thereof. Therefore, the foregoing description is illustrative and not limiting. The scope of the disclosure is defined not by the foregoing description but by the appended claims. All modifications within the range of equivalents of any modifications are intended to be embraced therein.

[0111] For example, the shape, pattern, size, arrangement, orientation, type, and number of each of the above-mentioned components are not limited to the above description and the contents illustrated in the drawings. The shape, pattern, size, arrangement, orientation, type, and number of each component may be configured arbitrarily as long as the function can be realized. Each component of the illustrated electromagnetic wave irradiation device 1 is a functional concept, and the specific form of each component is not limited to that illustrated.

[0112] For example, functions included in each configuration or step can be rearranged so as not to cause logical contradictions, and multiple configurations or steps can be combined into one or divided. Other modifications are possible within the scope of the present disclosure.

[0113] For example, a general-purpose electronic device such as a computer or a smartphone can be configured to function as the electromagnetic wave irradiation device 1 according to the embodiment described above. Specifically, a program describing the processing content for realizing each function of the electromagnetic wave irradiation device 1 according to the embodiment is stored in the memory of the electronic device, and the program is read and executed by a processor of the electronic device. Therefore, the present disclosure can also be realized as a program executable by a processor.

[0114] Alternatively, the present disclosure may be realized as a non-transitory computer-readable medium storing a program that can be executed by one or more processors to cause the electromagnetic wave irradiation device 1 according to an embodiment to execute each function. It should be understood that these are also included within the scope of the present disclosure.

[0115] In the above embodiment, the control unit 70 of the electromagnetic wave irradiation device 1 is described as irradiating the electromagnetic waves L1 at different timings in the first direction and the second direction included in a part of the second direction D2, but is not limited to this. The control unit 70 of the electromagnetic wave irradiation device 1 may irradiate the electromagnetic waves L1 at the same timing in the first direction and the second direction.

[0116] For example, the control unit 70 may use at least two of the first irradiating unit 11, the second irradiating unit 12, the third irradiating unit 13, and the fourth irradiating unit 14 to irradiate the electromagnetic waves L1 at the same timing. In this case, the detection unit 40 is not limited to a configuration having one PD, and may have PDs in the same number as the number of irradiating units 10 that operate at the same timing. The multiple PDs of the detection unit 40 may respectively detect multiple reflected waves L2 based on the multiple electromagnetic waves L1 irradiated from the irradiating units 10 that operate at the same timing.

[0117] In the above embodiment, the interval between the first orientation and the third orientation and the interval between the second orientation and the fourth orientation in the second direction D2 are described as being the same, but this is not limiting. The interval between the first orientation and the third orientation and the interval between the second orientation and the fourth orientation in the second direction D2 may be different from each other.

[0118] In the above embodiment, the irradiation unit 10 has been described as including a first irradiation unit that outputs the first electromagnetic wave L1 that is irradiated in the first direction and the second direction, and a second irradiation unit that outputs the second electromagnetic wave L1 that is irradiated in the third direction and the fourth direction, but is not limited thereto. The irradiation unit 10 may be configured as a single unit rather than a plurality of units.

[0119] For example, the irradiation unit 10 of the electromagnetic wave irradiation device 1 has been described as including the first irradiation unit 11, the second irradiation unit 12, the third irradiation unit 13, and the fourth irradiation unit 14, but is not limited to this. The configuration of the irradiation unit 10 is not limited to a configuration in which four LDs are arranged in an array. The irradiation unit 10 may have only a single LD, or may have a configuration in which a number of LDs other than four are arranged in an array. The irradiation unit 10 may have, for example, one LD having a plurality of light-emitting regions arranged in an array.

[0120] In the above embodiment, the control unit 70 of the electromagnetic wave irradiation device 1 has been described as irradiating the electromagnetic waves L1 by changing the direction along the first direction D1 in the order of the first orientation, the third orientation, the second orientation, and the fourth orientation, but is not limited thereto. The control unit 70 may irradiate the electromagnetic waves L1 at the same first timing in the first orientation and the third orientation, and may irradiate the electromagnetic waves L1 at a second timing different from the first timing in the second orientation and the fourth orientation.

[0121] In the above embodiment, the control unit 70 of the electromagnetic wave irradiation device 1 has been described as determining the length of the part of the period in accordance with the information on the vibration state detected by the sensor unit 50, but this is not limiting. The control unit 70 does not need to perform such a determination process. Accordingly, the electromagnetic wave irradiation device 1 does not need to have the sensor unit 50.

[0122] In the above embodiment, the control unit 70 of the electromagnetic wave irradiation device 1 predicts the displacement based on the vibration state of the electromagnetic wave irradiation device 1 based on the detection information, and determines the number of directions in which the electromagnetic waves L1 can be irradiated during a period in which the displacement amount of the electromagnetic wave irradiation device 1 falls within a predetermined range, but this is not limiting. The control unit 70 does not have to perform such a determination process.

[0123] In the above embodiment, the control unit 70 of the electromagnetic wave irradiation device 1 is described as detecting the road surface and the target object S located on the road surface, which are included in the object, by distinguishing them from each other based on the second measurement information, but this is not limited to this. The control unit 70 may detect any object other than the target object S located on the road surface as the target.

[0124] In the above embodiment, the number of the plurality of predetermined directions in the second direction D2 of the scanning area is described as eight, but this is not limited thereto. The number of the plurality of predetermined directions in the second direction D2 of the scanning area may be a number other than eight.

[0125] In the above embodiment, the number of orientations included in some of the plurality of predetermined directions is described as four, but this is not limited to this. The number of orientations included in some of the plurality of predetermined directions may be a number other than four.

[0126] In the above embodiment, the order in which the point cloud data is acquired has been described as being the order shown in Fig. 7, but is not limited to this. The order in which the point cloud data is acquired may be configured regularly or irregularly in any other form.

[0127] In the above embodiment, the first direction D1 and the second direction D2 are described as being orthogonal to each other, but this is not limited thereto. The first direction D1 and the second direction D2 may also intersect at an angle to each other. In the above embodiment, when the scanning area is depicted as a two-dimensional image, the first direction D1 includes the vertical direction and the second direction D2 includes the horizontal direction, but this is not limited thereto. When the scanning area is depicted as a two-dimensional image, the first direction D1 may include the horizontal direction and the second direction D2 may include the vertical direction.

[0128] In the above embodiment, the electromagnetic wave irradiation device 1 has been described as including the switching unit 30, but is not limited to this. The electromagnetic wave irradiation device 1 does not have to include the switching unit 30. In this case, the electromagnetic wave irradiation device 1 may be configured to include either the third lens 80c or the fourth lens 80d. The third lens 80c or the fourth lens 80d may be fixed and / or positioned so that the reflected wave L2 enters from outside the electromagnetic wave irradiation device 1 and is emitted to the detection unit 40.

[0129] In the above embodiment, the electromagnetic wave irradiation device 1 has been described as having a first optical system S1 arranged on the irradiation side that irradiates the electromagnetic wave L1 and a second optical system S2 arranged on the light-receiving side that receives the reflected wave L2, which are different configurations. However, this is not limited to this. The electromagnetic wave irradiation device 1 may be provided with an optical system that integrates the optical system that irradiates the electromagnetic wave L1 and the light-receiving system that receives the reflected wave L2. The integrated optical system may include at least the irradiation unit 10, the scanning unit 20, the detection unit 40, and the optical member 90.

[0130] The optical member 90 may be provided on a path along which the electromagnetic wave L1 irradiated by the irradiation unit 10 travels and on a path along which the reflected wave L2 incident from outside the electromagnetic wave irradiation device 1 travels. In this configuration, the scanning unit 20 may irradiate the electromagnetic wave L1 to the outside of the electromagnetic wave irradiation device 1 and cause the reflected wave L2 incident from the outside to travel to the optical member 90. The optical member 90 may cause the electromagnetic wave L1 from the irradiation unit 10 to travel to the scanning unit 20. In addition, the optical member 90 may cause the reflected wave L2 from the scanning unit 20 to travel to the detection unit 40.

[0131] The optical member 90 may be configured, for example, by a mirror or the like that has a reflecting surface on a part of the surface along which the electromagnetic wave L1 travels from the irradiation unit 10, which reflects the electromagnetic wave L1 to the scanning unit 20, and a surface on another part of the surface along which the electromagnetic wave L1 travels that transmits the reflected wave L2. Lenses or the like may be fixed and / or positioned and disposed on the paths of the electromagnetic wave L1 and the reflected wave L2 so that the electromagnetic wave L1 and the reflected wave L2 travel appropriately.

[0132] In the above embodiment, the electromagnetic wave irradiation device 1 is described as being mounted on a mobile object. Here, examples of the mobile object include a car, a motorcycle, a bicycle, a railroad car, an airplane, an AGV (automated guided vehicle), an AMR (autonomous mobile robot), a ship, a picking robot, and a general-purpose robot.

[0133] When the electromagnetic wave irradiation device 1 is mounted on a vehicle, a motorcycle, a bicycle, or the like, the present disclosure can be applied to detecting and measuring the distance to an object S on a road surface such as a road or sidewalk on which the vehicle is traveling.

[0134] When the electromagnetic wave irradiation device 1 is mounted on a railway vehicle, the present disclosure can be applied to detecting and measuring the distance to an object S on the running railroad tracks or the surrounding area thereof.

[0135] When the electromagnetic wave irradiation device 1 is mounted on an aircraft, the present disclosure can be applied to detecting and measuring the distance to an object S on a road surface such as a runway (used for takeoff and landing).

[0136] When the electromagnetic wave irradiation device 1 is mounted on an AGV or AMR, the present disclosure can be applied to detecting and measuring the distance to an object S on the road surface on which the vehicle is traveling.

[0137] When the electromagnetic wave irradiation device 1 is installed on a ship, the present disclosure can be applied to the detection and distance measurement of an object S relative to a pier or another ship when docking. In this case, the road surface in the above embodiment may be read as the pier or quay where the ship will dock. The control unit 70 of the electromagnetic wave irradiation device 1 may detect the pier or quay, which are included in the object, and the object S located on the pier or quay, by distinguishing them from each other based on the second measurement information.

[0138] When the electromagnetic wave irradiation device 1 is mounted on a picking robot or a general-purpose robot, the present disclosure can be applied to detecting and measuring the distance to the target object S relative to the work to be picked, the road surface on which the work is piled, or a container.

[0139] In the present embodiment, the electromagnetic wave irradiation device 1 is mounted on a mobile body, but the present invention is not limited to this. The electromagnetic wave irradiation device 1 may be mounted on a monitoring device, a roadside unit, or the like.

[0140] When the electromagnetic wave irradiation device 1 is mounted on a monitoring device, the present disclosure can be applied to detection and distance measurement of an object S to be monitored that exists in the surrounding area indoors or outdoors. Here, the monitored object is not limited to outdoor roads, sidewalks, quays, railroad tracks, railroad crossings, runways, indoor corridors, or the floor of a room, but may also be a moving object, a person or an animal, or a substance installed in the surrounding area.

[0141] When the electromagnetic wave irradiation device 1 is mounted on a roadside unit installed on the side of a road, the present disclosure can be applied to detecting and measuring the distance to an object S on a road surface such as a road or sidewalk in the surrounding area on which moving objects, pedestrians, etc. can move.

[0142] Some embodiments of the present disclosure are exemplified below. However, it should be noted that the embodiments of the present disclosure are not limited to these. [Supplementary Note 1] An electromagnetic wave irradiation device comprising: an irradiation unit that outputs electromagnetic waves; a scanning unit that changes the irradiation direction of the electromagnetic waves in a plurality of different directions and outputs them to a scanning area; a control unit that controls the irradiation unit and the scanning unit to change the irradiation direction of the electromagnetic waves and irradiate them multiple times in one cycle; and a detection unit that detects reflected waves of the electromagnetic waves reflected by an object present in the scanning area, wherein the electromagnetic wave irradiation device determines the presence or position of an object to be detected in the scanning area based on first measurement information generated based on reflected waves of the electromagnetic waves reflected by the object, the electromagnetic waves being irradiated multiple times during a partial period included in the one cycle. [Supplementary Note 2] The electromagnetic wave irradiation device according to Supplementary Note 1, wherein the one cycle includes a plurality of partial periods, and the first measurement information is generated during each of the partial periods. [Supplementary Note 3] The electromagnetic wave irradiation device according to Supplementary Note 2, which determines the presence or absence or the position of the object to be detected in the scanning area based on second measurement information generated based on a plurality of pieces of first measurement information. [Supplementary Note 4] The electromagnetic wave irradiation device according to Supplementary Note 3, wherein the control unit changes the irradiation direction of the electromagnetic waves along a first direction and a second direction intersecting the first direction during the one period, and changes the irradiation direction of the electromagnetic waves along the first direction in each of the plurality of different irradiation directions of the electromagnetic waves changed along the second direction. [Supplementary Note 5] The electromagnetic wave irradiation device according to Supplementary Note 4, wherein, during the partial period, the control unit changes the irradiation direction of the electromagnetic waves along the first direction in some of the irradiation directions of the plurality of different electromagnetic waves changed along the second direction. [Supplementary Note 6] The electromagnetic wave irradiation device according to Supplementary Note 5, wherein the plurality of pieces of first measurement information each have a different irradiation direction of the plurality of different electromagnetic waves changed along the second direction. [Supplementary Note 7] The electromagnetic wave irradiation device according to any one of Supplementary Notes 4 to 6, wherein the first direction is a direction perpendicular to a depth direction in the scanning area, and the second direction is a horizontal direction in the scanning area.[Supplementary Note 8] The electromagnetic wave irradiation device according to any one of Supplementary Notes 1 to 7, wherein the scanning unit has a reflecting surface that oscillates around a first axis and a second axis, and changes the radiation direction of the electromagnetic waves by orienting the reflecting surface in a plurality of different directions, and the control unit causes the irradiation unit to radiate the electromagnetic waves a plurality of times while orienting the reflecting surface in one direction about the second axis as a rotation axis and oscillating the reflecting surface about the first axis as a rotation axis. [Supplementary Note 9] The electromagnetic wave irradiation device according to Supplementary Note 8, wherein the reflecting surface oscillates around the first axis to change the irradiation direction of the electromagnetic waves along a first direction, and oscillates around the second axis to change the irradiation direction of the electromagnetic waves along a second direction. [Supplementary Note 10] The electromagnetic wave irradiation device according to any one of Supplementary Notes 1 to 9, further comprising a sensor unit that detects a vibration state, and the control unit determines the length of the partial period according to detection information of the vibration state by the sensor unit. [Supplementary Note 11] The electromagnetic wave irradiation device according to Supplementary Note 10, wherein the control unit determines, based on the vibration state acquired based on the detection information, a period during which the displacement amount of the electromagnetic wave irradiation device is within a predetermined range as a period for irradiating the electromagnetic waves for generating the first measurement information. [Supplementary Note 12] The electromagnetic wave irradiation device according to any one of Supplements 1 to 11, wherein the control unit distinguishes between and detects a road surface and the object located on the road surface, which are included in the object, based on the first measurement information. [Supplementary Note 13] The electromagnetic wave irradiation device according to any one of Supplements 1 to 12, wherein the control unit distinguishes between and detects a pier or a wharf, which are included in the object, and the object located on the pier or the wharf, based on the first measurement information.

[0143] REFERENCE SIGNS LIST 1 Electromagnetic wave irradiation device 10 Irradiation unit 11 First irradiation unit 12 Second irradiation unit 13 Third irradiation unit 14 Fourth irradiation unit 20 Scanning unit 21 Two-dimensional MEMS mirror 30 Switching unit 40 Detection unit 50 Sensor unit 60 Memory unit 70 Control unit 80a First lens 80b Second lens 80c Third lens 80d Fourth lens A1 First axis A2 Second axis D1 First direction D2 Second direction D3 Depth direction L1 Electromagnetic wave L2 Reflected wave P1 Point P2 Point P3 Point S Object S1 First optical system S2 Second optical system

Claims

1. An electromagnetic wave irradiation device comprising: an irradiation unit that outputs electromagnetic waves; a scanning unit that changes the irradiation direction of the electromagnetic waves to a number of different directions and outputs them to a scanning area; a control unit that controls the irradiation unit and the scanning unit to change the irradiation direction of the electromagnetic waves and irradiate them multiple times in one period; and a detection unit that detects reflected waves of the electromagnetic waves reflected by an object present in the scanning area, wherein the electromagnetic wave irradiation device determines the presence or absence or position of an object to be detected in the scanning area based on first measurement information generated based on reflected waves of the electromagnetic waves reflected by the object, the electromagnetic waves being irradiated multiple times during a portion of the one period.

2. The electromagnetic wave irradiation device according to claim 1, wherein the one period includes a plurality of the partial periods, and the first measurement information is generated in each of the partial periods.

3. The electromagnetic wave irradiation device according to claim 2, which determines the presence or absence or position of the object to be detected in the scanning area based on second measurement information generated based on a plurality of the first measurement information.

4. The electromagnetic wave irradiation device described in claim 3, wherein the control unit changes the irradiation direction of the electromagnetic wave along a first direction and a second direction intersecting the first direction during the one period, and changes the irradiation direction of the electromagnetic wave along the first direction for each of a plurality of different irradiation directions of the electromagnetic wave that are changed along the second direction.

5. The electromagnetic wave irradiation device according to claim 4, wherein, during the portion of the period, the control unit changes the irradiation direction of the electromagnetic waves along the first direction in some directions among a plurality of different irradiation directions of the electromagnetic waves that are changed along the second direction.

6. The electromagnetic wave irradiation device according to claim 5, wherein the plurality of first measurement information are each different in irradiation direction of the plurality of different electromagnetic waves that are changed along the second direction.

7. An electromagnetic wave irradiation device as described in claim 4, wherein the first direction is a direction perpendicular to the depth direction in the scanning area, and the second direction is a horizontal direction in the scanning area.

8. The electromagnetic wave irradiation device described in claim 1, wherein the scanning unit has a reflective surface that oscillates around a first axis and a second axis, and changes the radiation direction of the electromagnetic wave by directing the reflective surface in a number of different directions, and the control unit directs the reflective surface in one direction about the second axis as an axis of rotation, and irradiates the electromagnetic wave from the irradiation unit a number of times while oscillating the reflective surface about the first axis as an axis of rotation.

9. The electromagnetic wave irradiation device according to claim 8, wherein the reflecting surface changes the irradiation direction of the electromagnetic wave along a first direction by oscillating around the first axis, and changes the irradiation direction of the electromagnetic wave along a second direction by oscillating around the second axis.

10. An electromagnetic wave irradiation device as described in any one of claims 1 to 3, further comprising a sensor unit that detects a vibration state, wherein the control unit determines the length of the portion of the period according to detection information of the vibration state by the sensor unit.

11. The electromagnetic wave irradiation device described in claim 10, wherein the control unit determines, based on the vibration state acquired based on the detection information, a period during which the displacement amount of the electromagnetic wave irradiation device is within a predetermined range as a period for irradiating the electromagnetic waves to generate the first measurement information.

12. The electromagnetic wave irradiation device according to claim 1, wherein the control unit distinguishes and detects the road surface and the object located on the road surface, which are included in the object, based on the first measurement information.

13. The electromagnetic wave irradiation device according to claim 1, wherein the control unit distinguishes and detects a pier or a wharf included in the object, and the target object located on the pier or the wharf based on the first measurement information.

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