Optical controller

Abstract

To provide an optical controller which can acquire 3D information using single transceivers even if a mobile body is in an inclined state.SOLUTION: An optical controller emits light from an emission part and receives light reflected from an object by a light receiving part. And an acquisition part acquires inclination information regarding the inclination of a mobile body, and a control part, based on the inclination information, controls the emitting direction of the light emitted by the emission part.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a light control device that controls the transition of emitted light. [Background technology]

[0002] LIDAR is known, which detects a point cloud on an object surface by scanning horizontally while intermittently emitting laser light and receiving the reflected light. Patent Document 1 describes a method in which a LIDAR mounted on an automobile scans the surroundings one-dimensionally or two-dimensionally to detect information about the situation around the automobile. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-89691 Summary of the Invention [Problem to be solved by the invention]

[0004] To obtain information about the surrounding environment in three dimensions, a multi-layered LIDAR must be used. However, a multi-layered LIDAR requires as many optical transceivers as there are layers, which makes it very expensive. Furthermore, if a moving object, such as a vehicle equipped with a LIDAR, tilts, the direction of the laser light emitted by the LIDAR changes, making it impossible to detect objects correctly.

[0005] The above is an example of a problem that the present invention aims to solve. An object of the present invention is to provide a light control device that makes it possible to acquire three-dimensional information using a single transmitter / receiver even when a moving object is tilted. [Means for solving the problem]

[0006] The invention described in claim 1 is a light control device installed on a moving body, comprising an emission unit that emits light, a light receiving unit that receives the light reflected by an object, an acquisition unit that acquires tilt information regarding the tilt of the moving body, and a control unit that controls the emission direction of the light emitted by the emission unit based on the tilt information. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 2 is a block diagram showing the configuration of a rider unit according to the embodiment. [Figure 2] FIG. 2 is a block diagram showing the configuration of a light transmitting and receiving unit. [Figure 3] 3 shows waveforms of a trigger signal and a segment extraction signal. [Figure 4] 10 shows an example of a scanning state by the omnidirectional scanning unit. [Figure 5] The trajectory of the spiral scan is shown. [Figure 6] 1 shows the scanning field of view by spiral scanning. [Figure 7] 1 shows an example of a spiral scanning trajectory. [Figure 8] 3A and 3B show schematic diagrams illustrating changes in the detection state of a target due to tilting of a vehicle. [Figure 9] 10 illustrates the correction of the scan range by adaptive spiral scanning. [Figure 10] 10 shows an example of a trajectory of adaptive spiral scanning in the first embodiment. [Figure 11] 10 shows another example of the trajectory of the adaptive spiral scan in the first embodiment. [Figure 12] 10 shows another example of the trajectory of the adaptive spiral scan in the first embodiment. [Figure 13] 10 shows another example of the trajectory of the adaptive spiral scan in the first embodiment. [Figure 14] 1 is a flowchart of adaptive helical scanning in the first embodiment. [Figure 15] 1 shows a schematic diagram of the pitching motion of a vehicle. [Figure 16] 10 shows an example of a trajectory of adaptive spiral scanning in the second embodiment. [Figure 17] 10 is a flowchart of adaptive helical scanning in the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] In a preferred embodiment of the present invention, a light control device installed on a moving body comprises an emission unit that emits light, a light receiving unit that receives the light reflected by an object, an acquisition unit that acquires tilt information regarding the tilt of the moving body, and a control unit that controls the emission direction of the light emitted by the emission unit based on the tilt information.

[0009] The light control device emits light from an emitter and receives the light reflected by an object with a light receiver. The acquisition unit acquires tilt information related to the tilt of the moving object, and the control unit controls the direction of the light emitted by the emitter based on the tilt information. This allows the direction of the emitted light to be appropriately controlled in accordance with the tilt of the moving object.

[0010] In one aspect of the light control device, the tilt information includes information indicating a direction angle of the moving object in a first direction and a tilt angle of the moving object in a second direction intersecting the first direction. In this aspect, the emission direction of light is controlled based on the direction angle in the first direction and the tilt angle in the second direction.

[0011] In another aspect of the light control device, the tilt information includes a direction angle of rotational motion of the moving body in a first direction, an amplitude angle of the rotational motion in a second direction intersecting the first direction, and a frequency of the rotational motion. In this aspect, the emission direction of light is controlled based on the direction angle, amplitude angle, and frequency of the rotational motion.

[0012] In another aspect of the light control device, the control unit controls the emitting unit to continuously transition the light emitted by the emitting unit between the first direction and the second direction so that the transition locus of the light becomes spiral. In this aspect, since the light is emitted so that the transition locus becomes spiral, it is possible to receive light reflected by objects in all directions.

[0013] In another aspect of the light control device, the light receiving unit further includes a detector that detects at least one of a distance and an angle to the object based on the light receiving result of the light receiving unit. In this aspect, the light receiving unit can obtain at least one of a distance and an angle to the object based on the light receiving result of the light receiving unit.

[0014] In another preferred embodiment of the present invention, a light control method executed by a light control device installed on a moving body and including an emitter for emitting light and a light receiver for receiving the light reflected by an object includes: an acquisition step of acquiring tilt information regarding the tilt of the moving body; and a control step of controlling the emission direction of the light emitted by the emitter based on the tilt information. This method also makes it possible to appropriately control the direction of the emitted light in accordance with the tilt of the moving body.

[0015] In another preferred embodiment of the present invention, a program executed by a light control device installed on a mobile body and including an emission unit that emits light, a light receiving unit that receives the light reflected by an object, and a computer causes the computer to function as an acquisition unit that acquires tilt information regarding the tilt of the mobile body, and a control unit that controls the emission direction of the light emitted by the emission unit based on the tilt information. By executing this program on a computer, the direction of the emitted light can be appropriately controlled in accordance with the tilt of the mobile body.

[0016] In another preferred embodiment of the present invention, a light control device installed on a moving body comprises an emission unit that emits light, a light receiving unit that receives the light reflected by an object, an acquisition unit that acquires tilt information regarding the tilt of the moving body, and a control unit that controls the emission direction of the light emitted by the emission unit based on the tilt information so that the trajectory of the light emitted by the emission unit has a constant shape regardless of the tilt.

[0017] The light control device emits light from an emitter and receives the light reflected by an object with a light receiver. The acquisition unit acquires tilt information related to the tilt of the moving object, and the control unit controls the direction of the light emitted by the emitter based on the tilt information so that the trajectory of the light emitted by the emitter has a constant shape regardless of the tilt. This allows the direction of the emitted light to be appropriately controlled according to the tilt of the moving object. [Example]

[0018] Preferred embodiments of the present invention will now be described with reference to the drawings. [composition] FIG. 1 is a block diagram showing the configuration of a lidar unit 100 according to an embodiment of the light control device of the present invention. The lidar unit 100 of the embodiment is mounted on a moving object such as a vehicle. The lidar unit 100 is a TOF (Time Of Flight) type lidar (Lidar: Light Detection and Ranging, or Laser Illuminated Detection and Ranging) that measures the distance to an object (target) in all directions in the horizontal direction. As shown in the figure, the lidar unit 100 includes a light transmitting and receiving unit 1, a signal processing unit 2, an omnidirectional scanning unit 3, a scan angle control unit 4, a scan angle detection unit 5, and an attitude angle detection unit 6.

[0019] The light transmitting and receiving unit 1 includes a laser diode or the like, and generates laser pulses PL and supplies them to the omnidirectional scanning unit 3. The omnidirectional scanning unit 3 emits laser pulses (hereinafter also referred to as "transmitted light pulses Pt") in all 360° horizontal directions while changing the emission direction vertically. At this time, the omnidirectional scanning unit 3 emits the transmitted light pulses Pt for each segment (900 segments in this embodiment) obtained by dividing the 360° horizontal directions at equal angles. Furthermore, the omnidirectional scanning unit 3 receives reflected light of the transmitted light pulses Pt (hereinafter also referred to as "received light pulses Pr") within a predetermined period after emitting the transmitted light pulses Pt and supplies the reflected light to the light transmitting and receiving unit 1. The light transmitting and receiving unit 1 generates a signal (hereinafter also referred to as "segment signal Sseg") related to the received light intensity for each segment based on the received light pulses Pr and outputs the signal to the signal processing unit 2.

[0020] The scanning angle detection unit 5 detects the horizontal angle θ and vertical angle φ that indicate the emission direction of the transmission light pulse Pt emitted by the omnidirectional scanning unit 3 , and supplies them to the signal processing unit 2 .

[0021] The attitude angle detection unit 6 is, for example, a sensor attached to the vehicle, and detects the attitude of the vehicle on which the LIDAR unit 100 is mounted. Specifically, the attitude angle detection unit 6 detects the inclination of the vehicle caused by the external (road) environment, and calculates an angle θ in the direction in which the vehicle is inclined (hereinafter referred to as "inclination direction") as an estimated inclination value indicating the inclination. dir and the vehicle's inclination angle (hereinafter referred to as the "inclination angle") φ tilt and supplies it to the signal processing unit 2. Note that the vehicle tilt here does not mean the tilt (mounting error) that occurs when the rider unit 100 is mounted on the vehicle. Alternatively, the attitude angle control unit 6 detects the pitching motion of the vehicle and provides the pitching motion direction θ as a pitching motion estimated value indicating the pitching motion. dir , frequency f pitch , amplitude φ pitch , the phase shift p of the pitching motion relative to the frame time pitchand supply them to the signal processing unit 2. Note that instead of attaching a sensor to the vehicle, the attitude angle detection unit 6 may be configured to attach a sensor to the omnidirectional scanning unit 3 and detect the tilt of the omnidirectional scanning unit 3 itself.

[0022] The signal processing unit 2 outputs surrounding environment information including at least one of the distance to the object and the angle of the object based on the segment signal Sseg for each segment received from the light transmitting and receiving unit 1. The surrounding environment information is information that indicates the surrounding environment of the vehicle on which the LIDAR unit 100 is mounted, and specifically, information that indicates the distance and angle of objects that exist in all directions from the vehicle as the center.

[0023] The signal processing unit 2 determines a target horizontal angle θ as a control target based on the horizontal angle θ and the vertical angle φ detected by the scanning angle detection unit 5. x and the target vertical angle φ x and supplies it to the scan angle control unit 4. The scan angle control unit 4 generates the target horizontal angle θ x and the target vertical angle φ x Based on this, the omnidirectional scanning unit 3 controls the scanning angle of the transmitted light pulse Pt based on the target horizontal angle θ x and is controlled so as to emit a transmission light pulse Pt at a target vertical angle φ.

[0024] When the attitude angle detection unit 6 detects the tilt or pitching motion of the vehicle, the signal processing unit 2 generates a vertical angle φ (hereinafter referred to as the "corrected vertical angle") after correcting the amount of variation in the scan angle due to the tilt or pitching motion of the vehicle based on the scan angle θ detected by the scan angle detection unit 5 and the estimated tilt value or pitching motion value detected by the attitude angle detection unit 6, and defines this as the target vertical angle φ x to the scan angle control unit 4. Therefore, the scan angle control unit 4 can control the scan angle of the transmitted light pulse Pt so as to correct the influence of the tilt or pitching movement of the vehicle.

[0025] Next, a detailed description will be given of the light transmitting and receiving unit 1. The configuration of the light transmitting and receiving unit 1 is shown in Fig. 2. The light transmitting and receiving unit 1 mainly has a crystal oscillator 10, a synchronization control unit 11, an LD driver 12, a laser diode (LD) 13, a light receiving element 16, a current-voltage conversion circuit (transimpedance amplifier) ​​17, an A / D converter 18, and a segmentator 19.

[0026] The crystal oscillator 10 outputs a pulsed clock signal S1 to the synchronization control unit 11 and the A / D converter 18. In this embodiment, the clock frequency is set to 1.8 GHz, for example. Hereinafter, the clock indicated by the clock signal S1 will also be referred to as the "sample clock."

[0027] The synchronization control unit 11 outputs a pulse-like signal (hereinafter referred to as "trigger signal S2") to the LD driver 12. In this embodiment, the trigger signal S2 is 131072 (=2 17 ) sample clock. Hereinafter, the period from when trigger signal S2 is asserted until the next time it is asserted will also be referred to as the "segment period." Furthermore, synchronization control unit 11 outputs a signal (hereinafter referred to as the "segment extraction signal S3") to segmentator 19, which determines the timing at which segmentator 19, described later, extracts the output of A / D converter 18. The trigger signal S2 and segment extraction signal S3 are logical signals, and are synchronized as shown in FIG. 3, described later. In this embodiment, synchronization control unit 11 asserts segment extraction signal S3 for a time width (also referred to as the "gate width Wg") equivalent to 2048 sample clocks.

[0028] The LD driver 12 supplies a pulse current to the laser diode 13 in synchronization with a trigger signal S2 input from the synchronization control unit 11. The laser diode 13 is, for example, an infrared (905 nm) pulse laser, and emits an optical pulse based on the pulse current supplied from the LD driver 12. In this embodiment, the laser diode 13 emits an optical pulse of about 5 nsec.

[0029] The light pulse emitted from the laser diode 13 is sent to the omnidirectional scanning unit 3 via an optical system. The omnidirectional scanning unit 3 emits a transmission light pulse Pt, and receives a light pulse reflected by an object as a reception light pulse Pr, and sends it to the light receiving element 16.

[0030] The light receiving element 16 is, for example, an avalanche photodiode, and generates a weak current corresponding to the light intensity of the received light pulse Pr guided by the omnidirectional scanning unit 3. The light receiving element 16 supplies the generated weak current to a current-voltage conversion circuit 17. The current-voltage conversion circuit 17 amplifies the weak current supplied from the light receiving element 16, converts it into a voltage signal, and inputs the converted voltage signal to an A / D converter 18.

[0031] The A / D converter 18 converts the voltage signal supplied from the current-voltage conversion circuit 17 into a digital signal based on the clock signal S1 supplied from the crystal oscillator 10, and supplies the converted digital signal to the segmentator 19. Hereinafter, the digital signal generated by the A / D converter 18 for each clock will also be referred to as a "sample."

[0032] The segmentator 19 generates a digital signal, which is the output of the A / D converter 18 for 2048 sample clocks during the period of the gate width Wg during which the segment extraction signal S3 is asserted, as a segment signal Sseg. The segmentator 19 supplies the generated segment signal Sseg to the signal processing unit 2.

[0033] 3 shows the waveforms of the trigger signal S2 and the segment extraction signal S3 in time series. As shown in Fig. 3, in this embodiment, the segment period, which is the period of one cycle during which the trigger signal S2 is asserted, is set to a length of 131072 sample clocks (denoted as "smpclk" in the drawing), the pulse width of the trigger signal S2 is set to a length of 64 sample clocks, and the gate width Wg is set to a length of 2048 sample clocks.

[0034] In this case, the segment extraction signal S3 is asserted for only the period of the gate width Wg after the trigger signal S2 is asserted, so the segmentator 19 extracts 2048 samples output by the A / D converter 18 while the trigger signal S2 is asserted. The longer the gate width Wg, the longer the maximum measurement distance (measurement limit distance) from the lidar unit 100.

[0035] Next, the omnidirectional scanning unit 3 will be described in detail. The omnidirectional scanning unit 3 is composed of, for example, a rotatable mirror and an optical system for scanning the transmitted light pulse Pt over 360°. The direction in which the omnidirectional scanning unit 3 transmits and receives light pulses to and from the surrounding environment (hereinafter also referred to as the "emission direction") is determined by a horizontal angle θ and a vertical angle φ. FIG. 4 shows an example of a scanning state by the omnidirectional scanning unit 3. FIG. 4(A) is a perspective view showing the state in which the omnidirectional scanning unit 3 is performing horizontal scanning. FIG. 4(B) is a plan view showing the scanning state of the omnidirectional scanning unit 3 as viewed from above. The light pulse is scanned at a horizontal angle θ with respect to a predetermined horizontal reference axis. The horizontal angle θ changes 360° ([deg]) with respect to the horizontal reference axis. In other words, the light pulse can scan in all directions (0° to 360°). FIG. 4(C) shows the state in which the omnidirectional scanning unit 3 is scanning upward from the horizontal scanning state shown in FIG. 3(A). Specifically, the omnidirectional scanning unit 3 scans with light pulses at a vertical angle φ with respect to a vertical reference axis. In this way, the omnidirectional scanning unit 3 is capable of three-dimensional scanning by continuously changing the horizontal and vertical angles.

[0036] In the above configuration, the light transmitting and receiving unit 1 is an example of an emission unit and a light receiving unit in the present invention, the attitude angle detection unit 6 is an example of an acquisition unit in the present invention, the signal processing unit 2, the omnidirectional scanning unit 3 and the scan angle control unit 4 are an example of a control unit in the present invention, and the signal processing unit 2 is an example of a detection unit in the present invention.

[0037] [Scanning Control] (spiral scan) Next, we will explain the scanning by the omnidirectional scanning unit 3. The omnidirectional scanning unit 3 performs scanning of multiple layers in the vertical direction. Specifically, in this embodiment, the omnidirectional scanning unit 3 performs spiral scanning of seven layers (number of layers n=7) in the vertical direction.

[0038] FIG. 5 shows the trajectory of spiral scanning. FIG. 5(A) is a perspective view of the trajectory of spiral scanning, FIG. 5(B) is a plan view of the trajectory of spiral scanning, and FIG. 5(C) is a side view of the trajectory of spiral scanning. Note that FIG. 5 shows the trajectory formed by a point at a certain distance in the emission direction of the transmission light pulse Pt due to scanning by the omnidirectional scanning unit 3. In other words, FIG. 5 shows the trajectory drawn by the transmission light pulse Pt emitted by the omnidirectional scanning unit 3 on a spherical surface of a predetermined radius in space.

[0039] As shown in the figure, one spiral scan (one frame) by the omnidirectional scanning unit 3 begins at a start point S, makes seven spiral turns (seven turns) to reach an end point E, and then returns to the start point S. The omnidirectional scanning unit 3 repeats this spiral scan. Specifically, during one frame of spiral scanning, the horizontal angle θ changes from 0° to 360° seven times. During this time, the vertical angle φ changes at a constant rate from a vertical angle −φ0 at the start point S to a vertical angle φ0 at the end point E. The period during which the emission direction of the transmission light pulse Pt returns from the end point E to the start point S is called the “retrace range.” The retrace range is a range for returning the emission direction of the transmission light pulse Pt to a predetermined direction in order to repeat the spiral scan.

[0040] Next, the scanning field of view will be explained. Figure 6(A) shows the horizontal field of view of spiral scanning. In this embodiment, of the 360° in all directions, the retrace range is set to 90°, and the remaining 270° is set to the "effective horizontal field of view angle range θt". In other words, θt = 270°. The effective horizontal field of view angle range is the range excluding the retrace range from the 360° in all directions, and is the range in which effective segment data can be obtained from the received optical pulse Pr. Now, assuming that the 360° scan by the omnidirectional scanning unit 3 corresponds to 900 segments, Number of segments per turn = 900 In addition, the horizontal angular resolution Δθ is Δθ=360 / 900=0.4° / seg This becomes:

[0041] Figure 6(B) shows the vertical field of view of the spiral scan. If the number of layers (number of turns) of the spiral scan is n (=7) and the vertical angular resolution of one layer is Δφ = 5°, then: Vertical viewing angle range = (n-1) × Δφ = 30° The vertical angle φ changes in the range of -15°≦φ≦15°. If the vertical angle φ is changed from the negative side to the positive side in a spiral scan, then at time t=0, the vertical angle φ=-φ0=-15°.

[0042] Next, the values ​​of the horizontal angle θ and vertical angle φ in the above spiral scan will be explained. Now, it is assumed that the omnidirectional scanning unit 3 performs spiral scan with the following specifications. Number of layers: n=7 Frame rate: f frame =25Hz ·Vertical field of view lower limit: φ L =-10° ·Vertical field of view upper limit: φ H =+10° - Horizontal retrace start angle (effective horizontal field of view angle range): θ't = 270° + 360° × (7-1) = 2430° Return line end horizontal angle: 360° In this case, the scanning angular velocity ω, horizontal angle θ, horizontal scanning angle (cumulative within a frame) θ', and vertical angle φ are given by the following equations. Note that t is time, g(θ') is a function that expresses the retrace line, and mod is a remainder function.

[0043]

number

[0044] Figure 7 shows an example of the trajectory of a spiral scan when there is no tilting or pitching motion of the vehicle. Figure 7(A) is a perspective view of the spiral scan, Figure 7(B) is an XY plan view, Figure 7(C) is an XZ plan view, and Figure 7(D) is a YZ plan view.

[0045] (adaptive spiral scan) Next, adaptive spiral scanning will be described, which is performed when the vehicle is tilting or pitching.

[0046] (i) First Example The first embodiment relates to adaptive spiral scanning when the vehicle is tilted. Assume that the LIDAR unit 100 performing the above-mentioned spiral scanning is mounted on a vehicle. If the vehicle body tilts due to vehicle body vibrations such as pitching or rolling or road surface undulations, the omnidirectional scanning unit 3 mounted on the vehicle will also tilt.

[0047] Specifically, when the vehicle V is not tilted as shown in FIG. 8(A), the lidar unit 100 detects a low-positioned object OB by the light beam emitted from the omnidirectional scanning unit 3 as shown in FIG. 8(B). L and high-positioned objects OB H However, when the vehicle V is tilted downward as shown in Fig. 8(C), the lidar unit 100 detects the low-positioned object OB by the light beam as shown in Fig. 8(D). L However, it is possible to detect high-positioned objects OB H Although not shown, when the vehicle V is tilted upward, the lidar unit 100 cannot detect the high-positioned object OB. H It can detect low-positioned objects OB L will no longer be able to detect.

[0048] Therefore, when the vehicle V is tilted, the vertical angle of the light beam emitted by the omnidirectional scanning unit 3 is corrected according to the direction and angle of the tilt. For example, when the vehicle V is tilted downward as shown in FIG. 9(A), the light beam emitted from the omnidirectional scanning unit 3 is corrected to be directed upward from the standard emission direction, as shown by the arrow X in FIG. 9(B). FIG. 9(C) shows the trajectory of the spiral scan when there is no tilt in the vehicle V. In contrast, when the vehicle V is tilted downward by an angle φc, the omnidirectional scanning unit 3 changes the vertical angle of the spiral scan upward by an angle φc, as shown in FIG. 9(D). In other words, the omnidirectional scanning unit 3 directs the horizontal reference axis V0 of the spiral scan upward by an angle φc. As a result, even when the vehicle V is tilted, the lidar unit 100 can detect a low-positioned object OB. L and high-positioned objects OB H can be detected correctly.

[0049] Next, a specific process of the above correction will be described. Referring to Fig. 1, the attitude angle detection unit 6 detects the inclination of the vehicle. The inclination of the vehicle is determined by the inclination direction θ dir and the inclination angle φ, which is the angle at which the vehicle is inclined in the vertical plane. tilt The signal processing unit 2 then calculates the tilt direction θ dir and the tilt angle φ tilt Based on this, the corrected vertical angle φ is calculated using the following formula (2). Formula (2) is tilt This is an approximate formula that is valid for a small range of tilt angles, such as <30°, and the corrected vertical angle φ can be expressed as a simple function of the horizontal scanning angle θ', making it suitable for control implementation.

[0050]

number

[0051] Then, the signal processing unit 2 converts the calculated corrected vertical angle φ into a target vertical angle φ x The scan angle control unit 4 then supplies the input target vertical angle φ xIn this way, fluctuations in the spiral scanning range due to the inclination of the vehicle can be correctly corrected.

[0052] FIG. 10 shows the tilt direction θ dir =0°, tilt angle φ tilt = 3°. Note that the tilt angle φtilt is expressed as positive for upward and negative for downward with respect to the horizontal direction. Figure 10(A) is a perspective view of the spiral scan after correction, Figure 10(B) is an XY plan view, Figure 10(C) is an XZ plan view, and Figure 10(D) is a YZ plan view.

[0053] FIG. 11 shows the tilt direction θ dir =45°, inclination angle φ tilt 11(A) shows an example of the trajectory of the spiral scan when the angle is 3°. Fig. 11(A) is a perspective view of the spiral scan after correction, Fig. 11(B) is an XY plan view, Fig. 11(C) is an XZ plan view, and Fig. 11(D) is a YZ plan view.

[0054] FIG. 12 shows the tilt direction θ dir =0°, tilt angle φ tilt 12(A) shows an example of the trajectory of the spiral scan when the angle is 12°. Fig. 12(A) is a perspective view of the spiral scan after correction, Fig. 12(B) is an XY plan view, Fig. 12(C) is an XZ plan view, and Fig. 12(D) is a YZ plan view.

[0055] FIG. 13 shows the tilt direction θ dir =45°, inclination angle φ tilt 13A shows an example of the trajectory of the spiral scan when the angle is 12°. Fig. 13A is a perspective view of the spiral scan after correction, Fig. 13B is an XY plan view, Fig. 13C is an XZ plan view, and Fig. 13D is a YZ plan view.

[0056] Next, the process of the adaptive spiral scanning will be described. Fig. 14 is a flowchart of the adaptive spiral scanning of the first embodiment. First, the attitude angle detection unit 6 detects the inclination of the vehicle (step S11). Next, the attitude angle detection unit 6 calculates the vehicle inclination direction θ dir and the tilt angle φ tilt(Step S12) The detected tilt direction θ dir and the tilt angle φ tilt (hereinafter referred to as the "tilt estimation value") is sent to the signal processing unit 2 as the tilt estimation value.

[0057] The signal processing unit 2 calculates the corrected vertical angle φ using equation (2) based on the vertical angle θ detected by the scanning angle detection unit 5 and the tilt estimation value detected by the attitude angle detection unit 6 (step S13). The calculated corrected vertical angle φ is the target vertical angle φ x The target vertical angle φ is then sent to the scan angle control unit 4. x Based on this, the vertical angle φ of the transmitted optical pulse Pr is controlled (step S14).

[0058] (ii) Second Example The second embodiment relates to adaptive spiral scanning when the vehicle is pitching. As shown in FIG. 15, the vehicle V may experience pitching, which is a fluctuation in the pitch direction, due to factors such as the condition of the road surface on which it is traveling. Pitching also causes fluctuations in the direction of the light beam emitted from the omnidirectional scanning unit 3. Therefore, in the second embodiment, the lidar unit 100 detects the pitching of the vehicle V and corrects the vertical angle of the light beam emitted by the omnidirectional scanning unit 3 accordingly.

[0059] 1, the attitude angle detection unit 6 detects the pitching motion of the vehicle. The pitching motion of the vehicle is detected by the pitching motion direction θ dir and frequency f pitch and amplitude φ pitch and the phase shift p of the pitching motion relative to the frame time pitch The signal processing unit 2 calculates the corrected vertical angle φ based on these values ​​supplied from the attitude angle detection unit 6 using the following equation (3):

[0060]

number

[0061] Then, the signal processing unit 2 converts the calculated corrected vertical angle φ into a target vertical angle φ x The scan angle control unit 4 then supplies the input target vertical angle φ x In this way, fluctuations in the spiral scanning range due to the inclination of the vehicle can be correctly corrected.

[0062] Figure 16 shows the pitching motion direction θ dir =0°, amplitude φ pitch =3°, frequency f pitch An example of the spiral scan trajectory when the frequency is 2 Hz is shown below. pitch is expressed as positive for the upper side and negative for the lower side with respect to the horizontal direction. Figure 16(A) is a perspective view of the corrected spiral scan, Figure 16(B) is an XY plan view, Figure 16(C) is an XZ plan view, and Figure 16(D) is a YZ plan view.

[0063] Next, the process of the adaptive spiral scanning will be described. Fig. 17 is a flowchart of the adaptive spiral scanning of the second embodiment. First, the attitude angle detection unit 6 detects the pitching motion of the vehicle (step S21). Next, the attitude angle detection unit 6 calculates the pitching motion direction θ as a pitching motion estimation value. dir and frequency f pitch and amplitude φ pitch and the phase shift p of the pitching motion relative to the frame time pitch The pitching motion estimated value is sent to the signal processing unit 2 (step S22).

[0064] The signal processing unit 2 calculates the corrected vertical angle φ using equation (3) based on the vertical angle θ detected by the scanning angle detection unit 5 and the pitching motion estimated by the attitude angle detection unit 6 (step S23). The calculated corrected vertical angle φ is the target vertical angle φ x The target vertical angle φ is then sent to the scan angle control unit 4. x Based on this, the vertical angle φ of the transmitted optical pulse Pr is controlled (step S24).

[0065] [Variations] In the above embodiment, the number of layers in the spiral scan or partial multilayer scan is seven, but this is merely an example, and scanning can be performed with any number of layers. Also, in the above embodiment, the emission direction is shifted by increasing the perpendicular angle φ from the bottom layer to the upper layers, but instead, the emission direction may be shifted by decreasing the perpendicular angle φ from the top layer to the lower layers.

[0066] Furthermore, in the above embodiment, correction processing is performed for pitching motion, but correction processing for rolling motion may also be performed. [Explanation of symbols]

[0067] 1 Optical transmitter / receiver 2. Signal Processing Section 3 Omnidirectional scanning unit 4 Scanning angle control section 5. Scanning angle detection unit 6 Attitude angle detection unit 13 Laser diode 16 Photodetector

Claims

[Claim 1] A light control device installed in a moving body, an emission section that emits light; a light receiving unit that receives the light reflected by an object; an acquisition unit that acquires tilt information related to the tilt of the moving body; a control unit that controls an emission direction of the light emitted by the emission unit based on the tilt information; A light control device comprising:

Images