JP2016057141A - Distance measuring device, moving body device, and distance measuring method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a desired measuring distance within a desired measuring range while suppressing an increase in power consumption.SOLUTION: Disclosed is a distance measuring device which emits light from an optical scanning system including an LD, an LD control part for controlling the LD and a polygon mirror for deflecting light from the LD, and receives reflection light from an object to measure the distance up to the object. The LD control part changes an amount of light emission of the LD within a scanning range in the optical scanning system. In this case, while suppressing an increase in power consumption, a desired measuring distance can be obtained within a desired measuring range.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a distance measuring device, a mobile device, and a distance measuring method, and more specifically, a distance measuring device that emits light, receives reflected light from an object, and measures the distance to the object, and the distance The present invention relates to a mobile device including a measuring device and a distance measuring method for measuring the distance.

  2. Description of the Related Art Conventionally, a vehicle distance measuring device that emits light from an optical scanning system, receives reflected light from an object, and measures the distance to the object is known (see, for example, Patent Document 1).

  In the vehicle distance measurement device disclosed in Patent Document 1, it is difficult to obtain a desired measurement distance within a desired measurement range while suppressing an increase in power consumption.

  The present invention emits light from an optical scanning system including a light source, a control unit that controls the light source, and a deflector that deflects light from the light source, receives light reflected from the object, and sets a distance to the object. In the distance measuring device to measure, the control unit is a distance measuring device that changes a light emission amount of the light source within a scanning range by the optical scanning system.

  According to the present invention, it is possible to obtain a desired measurement distance within a desired measurement range while suppressing an increase in power consumption.

It is a figure which shows schematic structure of the distance measuring device which concerns on 1st Embodiment. 2A to 2C are diagrams (Nos. 1 to 3) for explaining the deflection operation by the polygon mirror, respectively. FIG. 3A is a diagram for explaining the LD control unit, and FIG. 3B is a diagram illustrating a light emission control signal Sk (1 ≦ k ≦ 3) and a light pulse corresponding to the light emission control signal Sk. It is. It is a figure which shows a mode that the light from LD10 is incident obliquely on a deflection | deviation reflective surface. It is a graph which shows the reflectance of the light in the deflection | deviation reflective surface within a scanning range. FIGS. 6A and 6B are diagrams for explaining the light emission pattern HVP for high speed running and the light emission pattern LVP for low speed running, respectively. It is a flowchart for demonstrating the 1st example of a distance measuring method. It is a figure for demonstrating the hysteresis with respect to the threshold values Vth1 and Vth2 of the light emission pattern HVP for high speed driving | running, and the light emission pattern LVP for low speed driving | running | working. FIG. 9A and FIG. 9B are diagrams for explaining the rightward traveling light emission pattern RDP and the leftward traveling light emission pattern LDP, respectively. It is a flowchart for demonstrating the 2nd example of the distance measurement method. It is a figure for demonstrating the hysteresis with respect to the threshold-value + Rth1, -Rth1, + Rth2, -Rth2 of the steering angle of the light emission pattern HVP for high-speed driving | running | working, the light emission pattern RDP for right direction travel, and the light emission pattern LDP for left direction travel. FIGS. 12A and 12B are diagrams for explaining the light emission pattern HRP for fast right traveling and the light emission pattern LRP for slow right traveling, respectively. It is a flowchart for demonstrating the 3rd example of a distance measuring method. FIGS. 14A to 14C are diagrams (No. 1 to No. 3) for explaining the deflection operation by the deflector according to the second embodiment, respectively. It is a graph which shows the reflectance of the light in the deflection | deviation reflective surface in the scanning range of 2nd Embodiment. FIG. 16A and FIG. 16B are diagrams for describing the high-speed running light emission pattern HVP and the low-speed running light emission pattern LVP ′, respectively. FIG. 17A and FIG. 17B are diagrams for explaining the light emission pattern HLP ′ for high speed left traveling and the light emission pattern RDP ′ for right traveling, respectively. 10 is a flowchart for explaining a distance measurement method according to Modification 1; 10 is a flowchart for explaining a distance measurement method according to Modification 2; 10 is a flowchart for explaining a distance measurement method according to Modification 3; 10 is a flowchart for explaining a distance measurement method according to Modification 4; 10 is a flowchart for explaining a distance measurement method according to Modification 5;

<< First Embodiment >>
Below, the distance measuring device 100 of 1st Embodiment of this invention is demonstrated with reference to FIGS.

  FIG. 1 is a block diagram illustrating a schematic configuration of the distance measuring apparatus 100.

  For example, the distance measuring device 100 is mounted on an automobile as a moving body, emits light, receives reflected light from an object (for example, a preceding vehicle, a stopped vehicle, an obstacle, a pedestrian, etc.) and reaches the object. Measure the distance.

  As shown in FIG. 1, the distance measuring apparatus 100 includes an LD 10 (laser diode) as a light source, an optical scanning system including an LD control unit 12 that controls the LD 10 and an irradiation optical system 14, a light receiving optical system 16, and light detection. And a detection system including a PD 18 (photo detector) and a PD output detection unit 20 as a measuring device, a measurement control unit 22 (ranging system), a speed acquisition unit 23, and a steering angle acquisition unit 25. The distance measuring device 100 is supplied with power from, for example, a battery (storage battery) of an automobile.

  The LD 10 is a kind of semiconductor laser and is also called an edge emitting laser. The laser light emitted from the LD 10 is guided by the irradiation optical system 14 and irradiated to the object (target object).

  Specifically, the irradiation optical system 14 includes, as an example, a coupling lens 26 disposed on the optical path of the laser light from the LD 10 and a polygon mirror disposed on the optical path of the laser light via the coupling lens 26. 28 (deflector) (see FIGS. 2A to 2C). Here, the polygon mirror 28 has a square cross section perpendicular to the rotation axis, but may be another regular polygon such as a regular hexagon.

  As a deflector, other mirrors such as a galvanometer mirror and a MEMS mirror may be used instead of the polygon mirror.

  Therefore, the laser beam from the LD 10 is shaped into a laser beam having a predetermined beam profile by the coupling lens 26, deflected by, for example, a horizontal plane by the polygon mirror 28, and irradiated onto the object. That is, the object is scanned, for example, in the horizontal direction by the laser beam.

  Laser light (scanning light) applied to the object is reflected (scattered) by the object, and a part of the reflected light (scattered light) is guided to the PD 18 via the light receiving optical system 16.

  The light receiving optical system 16 includes a light receiving lens (for example, a condensing lens) as an example, and follows substantially the same path as the incident light (reflected by the polygon mirror 28 and incident on the object) out of the reflected light from the object. The incoming reflected light is imaged on the PD 18.

  When the PD 18 receives reflected light from an object, the PD 18 outputs a light reception signal, which is an electrical signal corresponding to the amount of the reflected light, to the PD output detection unit 20.

  The operation of the PD output detection unit 20 includes two operations of signal amplification of the light reception signal and timing detection of the light reception signal. The signal amplification of the received light signal is amplified using a signal amplifier such as an amplifier, and the detection of the timing of the received light signal is performed using a comparator such as a comparator, and the rising of the received light signal from the PD 18 becomes a certain output (threshold level) or more. Detect the waveform part. When the PD output detection unit 20 detects the light reception signal (rising waveform portion), it outputs the detection timing to the measurement control unit 22.

  The speed acquisition unit 23 acquires the speed of the automobile and outputs the acquisition result to the measurement control unit 22 as a speed signal. As the speed acquisition unit 23, for example, one that calculates from the number of pulses of a vehicle speed signal used in a car navigation system or one that calculates from GPS information is used. The speed acquisition unit 23 may acquire the speed from a vehicle speed detector for a speedometer installed in the automobile.

  The steering angle acquisition unit 25 acquires the steering angle (size and direction of the steering angle) of the automobile and outputs the acquisition result to the measurement control unit 22 as a steering angle signal. Here, as the rudder angle acquisition unit 25, for example, a rudder angle sensor that measures the rudder angle of a steering (steering device) of an automobile is used. The automobile travels in a direction (traveling direction) according to the steering angle of the steering.

  The LD control unit 12 has a plurality (i pieces) of LD drive circuits D1 to Di. The components of each LD drive circuit include a capacitor for storage and a transistor for switching (see FIG. 3A). In each LD driving circuit, the capacitor can be charged and discharged by switching the transistor. FIG. 3A shows a case where i = 3 as an example.

  More specifically, different charge amounts Q1 to Qi are stored in the capacitors CND1 to CNDi of the i LD driving circuits D1 to Di. Here, assuming that the capacitances of the capacitors CND1 to CNDi are C1 to Ci and the voltage between the plates is V1 to Vi, C1 × V1> C2 × V2>...> C (i−1) × V (i−1) )> Ci × Vi, that is, Q1> Q2>...> Q (i-1)> Qi. Here, the capacitors and transistors of one LD drive circuit Dk (1 ≦ k ≦ i) among i LD drive circuits D1 to Di are respectively referred to as capacitor CNDk (1 ≦ k ≦ i) and transistor Trk (1 ≦ k ≦ i). ≦ i).

  The capacitor CNDk is connected in series to the LD 10 via the transistor Trk. The capacitors CNDk and LD10 are turned on when the transistor Trk is ON, and are turned off when the transistor Trk is OFF.

  A voltage Vk (1 ≦ k ≦ i) is applied between the electrode plates of the capacitor CNDk (between both electrodes), and when the transistor Trk is OFF, a charge amount Qk (= CkVk) is accumulated in the capacitor CNDk, and the transistor Trk When is turned on, electric charge (time integral value of current) is supplied from the capacitor CNDk to the LD 10.

  Here, a light emission control signal (rectangular pulse signal) is selectively output from the measurement control unit 22 to any one of i transistors of the LD driving circuit via the transistor driving unit (see FIG. 3 (A)). Specifically, the measurement control unit 22 outputs a light emission control signal Sk (1 ≦ k ≦ i) corresponding to the LD drive circuit Dk to be controlled among the i LD drive circuits D1 to Di to the transistor drive unit 29. . Therefore, the transistor drive unit 29 outputs the light emission control signal Sk to the corresponding LD drive circuit Dk.

  In this case, when the light emission control signal Sk changes from the low level to the high level, the transistor Trk of the LD drive circuit Dk is turned from OFF to ON, and while the transistor Trk is ON, the charge from the capacitor CNDk (1 ≦ k ≦ i) Is discharged, and a current (drive current) is supplied to the LD 10. When the light emission control signal Sk changes from the high level to the low level, the transistor Trk is turned from ON to OFF, and the charge amount Qk (= CkVk) is quickly accumulated in the capacitor CNDk.

  In other words, in the LD drive circuit Dk, when the transistor Trk is OFF, the capacitor CDNk is charged, and when the transistor Trk is ON, the charge is discharged from the capacitor CDNk (supplied to the LD 10).

  Here, the integrated light amount (time integrated value of light output) of one light pulse emitted from the LD 10 is substantially proportional to the amount of charge supplied to the LD 10 (see FIG. 3B). Therefore, in the case shown in FIGS. 3A and 3B (i = 3), the light pulse (large pulse) emitted from the LD 10 when the charge amount Q1 is supplied to the LD 10 is shown. When the maximum value of the optical output is P1max and when the charge amount Q2 is supplied to the LD10, the maximum value of the optical output of the light pulse (medium pulse) emitted from the LD10 is P2max, and when the charge amount Q3 is supplied to the LD10 If the maximum value of the light output of the light pulse (small pulse) emitted from the LD 10 is P3max, P1max> P2max> P3max is established. The half width of each light pulse becomes shorter as the maximum value of the light output is smaller. The shorter the half-value width of the light pulse (the smaller the maximum value of the light output), the shorter the rise time. Therefore, when determining the detection timing of the received light signal, it is less susceptible to jitter, and in turn detects the distance to the object. Accuracy can be improved. Note that the pulse width of the laser light (light pulse) emitted from the LD 10 is, for example, several ns to 50 ns.

  As can be seen from the above description, the measurement control unit 22 selects the LD drive circuit Dk to be controlled from the i LD drive circuits D1 to Di, that is, the light emission control signal Sk is selected, and is supplied to the LD 10. The amount of charge (current integrated value of current) is determined. In this way, any one of a plurality of light pulses having different light outputs can be selectively emitted from the LD 10.

  In the measurement control unit 22, the time difference between the output timing of the light emission control signal Sk and the detection timing of the light reception signal from the PD output detection unit 20 is estimated as a round trip distance to the object (twice the distance to the object), By converting the time difference into a distance, the reciprocating distance between the object and the distance to the object is measured.

  More specifically, the measurement control unit 22 has a clock function that starts timing at the rising timing of the light emission control signal Sk and ends timing at the detection timing of the light reception signal from the PD output detection unit 20. The time measured by this clock function is the time during which the laser beam propagates (reciprocates) between the distance measuring device 100 and the object. By converting this time into a distance, the object is reciprocated between the object and the object. The distance can be determined.

  A measurement result (distance information) in the measurement control unit 22 is output as a measurement signal to an ECU (engine control unit) of the automobile. The ECU outputs a control signal (light emission command signal) to the measurement control unit 22 and performs, for example, vehicle speed control based on the measurement result of the measurement control unit 22. Examples of speed control for automobiles include automatic braking (autobraking).

  Further, the measurement control unit 22 generates one light emission control signal Sk (1 ≦ k) from the light emission control signals S1 to Si based on at least one of the acquisition result in the speed acquisition unit 23 and the acquisition result in the steering angle acquisition unit 25. ≦ i) is selected, and the light emission control signal Sk is output to the LD controller 12.

  In addition, the measurement control unit 22 outputs a rotation control signal to the polygon mirror 28, and rotates the polygon mirror 28 at a predetermined number of rotations (rotation speed). The measurement control unit 22 also receives a timing signal indicating the rotational position (position around the rotation axis) of the polygon mirror 28 from the polygon mirror 28, and sends the light emission control signal Sk to the LD control unit in synchronization with the timing signal. 12 is output. Hereinafter, the rotation axis of the polygon mirror 28 is also simply referred to as “rotation axis”.

  Here, as an example, the scanning range in the substantially horizontal direction by the optical scanning system including the polygon mirror 28 is such that the center (scanning angle 0 °) coincides with the straight traveling direction of the automobile, and one end (for example, the left end) and the other end (for example) For example, the scanning angle (deflection angle) at each of the right ends is set to be 70 ° (140 ° in the entire scanning range) (see FIGS. 2A to 2C). The “straight direction of the automobile” means the traveling direction of the automobile when the steering angle of the steering is 0 °. Hereinafter, the scanning range by the optical scanning system is also simply referred to as “scanning range”.

  More specifically, the direction passing through the rotation center (for example, the rotation axis) of the polygon mirror 28 and the center of the scanning range is parallel to the straight traveling direction of the automobile. Note that the scanning range only needs to include the straight direction of the automobile, and the center may be shifted from the straight direction of the automobile.

  FIG. 2A shows a state in which the laser beam from the LD 10 is deflected by the polygon mirror 28 toward one end (left end) of the scanning range. Here, the incident angle θ of light on the deflecting reflecting surface viewed from the rotation axis direction is 35 °.

  FIG. 2C shows a state in which the laser beam from the LD 10 is deflected by the polygon mirror 28 toward the other end (right end) of the scanning range. Here, the incident angle θ of light on the deflecting reflecting surface viewed from the rotation axis direction is 35 °.

  FIG. 2B shows a state in which the laser beam from the LD 10 is deflected by the polygon mirror 28 toward the center of the scanning range. Here, the incident angle of light on the deflecting reflecting surface viewed from the rotation axis direction is 0 °.

  As a result, it can be seen that the incident angle of light on the deflecting / reflecting surface viewed from the rotation axis direction gradually decreases from one end (upstream end) and the other end (downstream end) of the scanning range to the center.

  By the way, the light reflectance increases as the incident angle of the light on the deflecting reflecting surface viewed from the direction of the rotation axis decreases. Here, as shown in FIG. 5, the reflectance of light on the deflecting reflecting surface in the scanning range is expressed by a curve having one maximum value (maximum value) at the center which is substantially symmetric to the center of the scanning range. Is done. The vertical axis in FIG. 5 represents the rate of decrease (%) from the maximum value when the maximum value of the reflectance is 0%.

  As described above, since the reflectance of light on the deflection reflection surface varies within the scanning range, the amount of light emitted by the LD 10 is adjusted according to this variation, that is, according to the scanning timing (light deflection direction). The distribution of the amount of scanning light within the scanning range can be set to a desired distribution.

  Further, the laser beam from the LD 10 is incident with an inclination when viewed from a direction orthogonal to the rotation axis (here, the horizontal direction) (see FIG. 4). As described above, the light from the LD 10 is obliquely incident on the deflecting / reflecting surface, whereby the object can be scanned with the scanning light so that the light does not return to the LD 10. Note that the laser light incident on the deflecting / reflecting surface is preferably such that the S-polarized component is larger than the P-polarizing component with respect to the deflecting / reflecting surface, and the S-polarized component is most preferably 100%.

  Here, when the automobile is traveling at a high speed, particularly when a distant object is detected in a small angle range (for example, about 5 ° to 35 °) including the straight traveling direction (the longitudinal direction of the automobile) (the measurement distance is increased). ) Is desired, while it is less desirable to detect distant objects in other angular ranges. That is, while traveling at a high speed, it is desired to increase the measurement distance in a substantially straight direction, but it is not desirable to widen the measurement range. In high-speed driving, the steering angle of the steering wheel is small and the braking distance is long.Therefore, it is highly necessary to detect an object in the straight direction (traveling direction) early, while an object in a direction far from the straight traveling direction is This is because the need for early detection is low. The “measurement range” means a range in which a measurement distance sufficient for braking the automobile is required within the scanning range.

  Therefore, when the automobile is traveling at a high speed, as shown in the lower diagram of FIG. 6A, the amount of light emitted from the LD 10 increases stepwise from one end (for example, the left end) and the other end (for example, the right end) of the scanning range to the center. It is preferable to control so that it becomes.

  Here, the scanning range is divided into, for example, 12 ranges N1 to N12 from the left end to the right end. The first, second, eleventh, and twelfth ranges N1, N2, N11, and N12 from the left end are scanned with a small pulse. The third, fourth, ninth, and tenth ranges N3, N4, N9, and N10 counted from the left end are scanned with medium pulses. Then, the fifth to eighth ranges N5 to N8 counted from the left end are scanned with a large pulse. Here, the straight driving direction of the automobile is included in the range N5 to N8. Note that the number of divisions of the scanning range is not limited to 12, but is preferably 3 or more.

  Hereinafter, the light emission pattern shown in the lower part of FIG. 6A is referred to as a high-speed light emission pattern HVP. In the high-speed running light emission pattern HVP, the number of scans M is set. The area indicated by hatching in FIG. 6 (A) shows the estimated stop range of the automobile according to the measurement distance and the speed of the automobile. In high-speed traveling, the steering angle is small and the braking distance is long, so the estimated stop range is a narrow-angled fan shape that is elongated in a substantially straight direction (traveling direction). In the upper part of FIG. 6A, measurement distances (maximum distance that can be measured) corresponding to small pulses, medium pulses, and large pulses are shown. The “estimated stop range” corresponds to the “measurement range” described above.

  By causing the LD 10 to emit light with the high-speed running light emission pattern HVP, the measurement distance in the substantially straight direction (traveling direction) can be increased during high-speed running, and the power consumption can be reduced. Further, as described above, the reflectance of light on the deflecting reflecting surface is maximized at the center of the scanning range, so that it is possible to promote an increase in measurement distance in a substantially straight direction.

  On the other hand, while the automobile is traveling at a low speed, it is desired to widen the measurement range, but it is not desirable to increase the measurement distance. In the case of low-speed traveling, it is assumed that the steering angle of the steering is increased due to, for example, sudden steering, and it is highly necessary to detect an object greatly deviating from the straight traveling direction, and the braking distance can be shortened. Also, the closer to the left and right ends of the scanning range, the lower the driver's visibility, so it is desirable to increase the measurement distance.

  Therefore, when the vehicle is traveling at a low speed, it is preferable to control the light emission amount of the LD 10 so as to increase stepwise from the center of the scanning range to the left end and the right end as shown in FIG. 6B.

  Here, the scanning range is divided into 12 ranges N1 to N12 from the left end to the right end. The first, second, eleventh, and twelfth ranges N1, N2, N11, and N12 from the left end are scanned with a large pulse. The third, fourth, ninth, and tenth ranges N3, N4, N9, and N10 counted from the left end are scanned with medium pulses. Then, the fifth to eighth ranges N5 to N8 counted from the left end are scanned with small pulses. Here, the straight driving direction of the automobile is included in the range N5 to N8. Note that the number of divisions of the scanning range is not limited to 12, but is preferably 3 or more.

  Hereinafter, the light emission pattern shown in the lower diagram of FIG. 6B is referred to as a low-speed travel light emission pattern LVP. In the light emission pattern LVP for low-speed traveling, the number of scans M is set. The area shown by hatching in FIG. 6B shows the estimated stop range of the automobile with respect to the measurement distance and the speed of the automobile. In low-speed traveling, it is assumed that the steering angle becomes large and the braking distance becomes short. Therefore, the estimated stop range becomes a fan with a short diameter and a wide angle that covers almost the entire scanning range. In the upper part of FIG. 6B, measurement distances corresponding to small pulses, medium pulses, and large pulses are shown.

  By causing the LD 10 to emit light with the low-speed running light emission pattern LVP, it is possible to widen the measurement range and reduce power consumption during low-speed running. In particular, the measurement distance at the left end and the right end of the measurement range with low driver visibility can be increased.

  Hereinafter, a first example of a distance measuring method using the distance measuring apparatus 100 will be described with reference to FIG. The flowchart in FIG. 7 is based on a processing algorithm executed by the measurement control unit 22. The distance measuring device 100 is activated when the automobile engine is started. Then, when the engine of the automobile is started, a light emission command signal (control signal) is output from the ECU to the measurement control unit 22, and a series of processes in FIG. 7 is started. The memory of the measurement control unit 22 stores a low-speed running light emission pattern LVP and a high-speed running light emission pattern HVP in advance, and either of them can be set (read out) as the light emission pattern of the LD 10. Here, the distance measuring device 100 may not have the rudder angle acquisition unit 25.

  In the first step S1, the vehicle speed V is set to an initial value (0 km / h).

  In the next step S2, it is determined whether or not the vehicle speed V (acquisition result in the speed acquisition unit 23) is less than a threshold value Vth1 (for example, 30 km / h). If the determination in step S2 is affirmed, the process proceeds to step S3. On the other hand, if the determination in step S2 is negative, the process proceeds to step S8.

  In step S3, a low-speed running light emission pattern LVP is set as the light emission pattern of the LD10.

  In the next step S4, the distance L to the object is measured and acquired. Specifically, the LD 10 is caused to emit light with the low-speed driving light emission pattern LVP, and the distance L to the object is measured and acquired at each light emission timing of the LVP (each range of the scanning range). The light emission in the low-speed driving light emission pattern LVP outputs a light emission control signal S1 corresponding to a large pulse when the ranges N1, N2, N11, and N12 in the scanning range are scanned, and the ranges N3, N4, N9, and N10 The light emission control signal S2 corresponding to the middle pulse is output when scanning, and the light emission control signal S3 corresponding to the small pulse is output when the range N5 to N8 is scanned. Here, the object is scanned by a preset number of scans M, and the distance L is measured and acquired in each range for each scan.

  In the next step S5, the setting of the low-speed running light emission pattern LVP is canceled.

  In the next step S6, the vehicle speed V (acquisition result in the speed acquisition unit 23) is acquired.

  In the next step S7, it is determined whether or not to end the measurement. If the determination in step S7 is affirmative, the flow ends. On the other hand, if the determination in step S7 is negative, the process returns to step S2. The determination in step S7 is affirmed when the automobile engine is stopped.

  In step S8, the light emission pattern HVP for high speed running is set as the light emission pattern of the LD10.

  In the next step S9, the distance L to the object is measured and acquired. Specifically, the LD 10 is caused to emit light with the light emission pattern HVP for high-speed travel, and the distance L to the object is measured and acquired for each light emission timing of the HVP (for each range of the scanning range). Light emission in the high-speed running light emission pattern HVP outputs a light emission control signal S3 corresponding to a small pulse when the ranges N1, N2, N11, and N12 in the scanning range are scanned, and the ranges N3, N4, N9, and N10 The light emission control signal S2 corresponding to the middle pulse is output when scanning, and the light emission control signal S1 corresponding to the large pulse is output when the range N5 to N8 is scanned. Here, the object is scanned by a preset number of scans M, and the distance L is measured and acquired in each range for each scan.

  In the next step S10, the setting of the high-speed running light emission pattern HVP is canceled.

  In the next step S11, the vehicle speed V (acquisition result in the speed acquisition unit 23) is acquired.

  In the next step S12, it is determined whether or not the vehicle speed V is equal to or higher than a threshold value Vth2 (for example, 40 km / h). If the determination in step S12 is negative, the process returns to step S2. On the other hand, if the determination in step S12 is affirmative, the process returns to step S8.

  As described above, when the threshold value of the speed V after setting the HVP is a threshold value Vth2 larger than Vth1, the threshold value for shifting to LVP is changed to Vth2 when V ≧ Vth2. When V <Vth2, the threshold value for shifting to LVP remains Vth1. That is, here, as shown in FIG. 8, hysteresis is provided by setting two threshold values of the speed V at which the light emission pattern is transitioned between HVP and LVP. As a result, it is possible to prevent frequent switching in the vicinity of the threshold value, and to set a threshold value adapted to each of the low speed traveling and the high speed traveling.

  By the way, when the steering angle of the steering is rightward, since the traveling direction of the automobile is rightward with respect to the straight traveling direction of the automobile, it is desired to increase the measurement distance toward the right side in the scanning range. This is because, in particular, it is highly necessary to increase the measurement distance in the traveling direction, that is, to detect an object in the traveling direction early.

  Therefore, when the rudder angle is rightward, the LD 10 is driven by the rightward traveling light emission pattern RDP, which is a light emission pattern in which the light emission amount increases stepwise from the left end to the right end of the scanning range as shown in the lower diagram of FIG. It is preferable to emit light. Even in the right-direction traveling light emission pattern RDP, the scanning range is divided into 12 ranges N1 to N12, similar to the high-speed traveling light-emitting pattern HVP and the low-speed traveling light-emitting pattern LVP. The first to third ranges N1 to N3 counted from the left end of the scanning range are scanned with a small pulse, and the fourth to sixth ranges N4 to N6 counted from the left end of the scanning range are scanned. The middle pulse is scanned, and the seventh to twelfth ranges N7 to N12 counted from the left end of the scanning range are scanned with large pulses. Here, the straight traveling direction of the automobile is included in the scanning range (N1 to N12). Note that the number of divisions of the scanning range is not limited to 12, but the main point is preferably 2 or more.

  The number of scans M is also set in the rightward traveling light emission pattern RDP. The area indicated by hatching in FIG. 9A shows the estimated stop range of the automobile according to the measurement distance and the speed of the automobile. Since the steering angle is rightward when traveling in the right direction, the estimated stop range is a fan shape extending in the right direction as the traveling direction from the automobile. 9A shows the measurement distances corresponding to the small pulse, medium pulse, and large pulse, respectively.

  By causing the LD 10 to emit light with the rightward traveling light emission pattern RDP, it is possible to lengthen the measurement distance in the substantially traveling direction and reduce power consumption while traveling in the right direction.

  On the other hand, when the steering angle of the steering is leftward, the traveling direction of the automobile is leftward with respect to the straight traveling direction. Therefore, it is desirable to increase the measurement distance toward the left side in the scanning range. This is because, in particular, it is highly necessary to increase the measurement distance in the traveling direction, that is, to detect an object in the traveling direction early.

  Therefore, when the steering angle is leftward, as shown in the lower diagram of FIG. 9 (B), the LD 10 is moved by the left-direction traveling light-emitting pattern LDP, which is a light-emitting pattern in which the amount of emitted light increases stepwise from the right end to the left end of the scanning range. It is preferable to emit light. Also in the left-direction traveling light emission pattern LDP, the scanning range is divided into 12 ranges N1 to N12, similar to the high-speed traveling light-emitting pattern HVP and the low-speed traveling light-emitting pattern LVP. The first to sixth ranges N1 to N6 counted from the left end of the scanning range are scanned with a large pulse, and the seventh to ninth ranges N7 to N9 counted from the left end of the scanning range are scanned. The middle pulse is scanned, and the tenth to twelfth ranges N10 to N12 counted from the left end of the scanning range are scanned with small pulses. Here, the straight traveling direction of the automobile is included in the scanning range (N1 to N12). Note that the number of divisions of the scanning range is not limited to 12, but the main point is preferably 2 or more.

  The number of scans M is also set in the left-direction light emission pattern LDP. The area shown by hatching in FIG. 9B shows the estimated stop range of the automobile according to the measurement distance and the speed of the automobile. In the leftward traveling, the rudder angle is leftward, so that the estimated stop range is a fan shape extending in the leftward direction that is the traveling direction from the automobile. 9B shows the measurement distances corresponding to the small pulse, medium pulse, and large pulse, respectively.

  By causing the LD 10 to emit light with the leftward traveling light emission pattern LDP, it is possible to lengthen the measurement distance in the substantially traveling direction and reduce power consumption while traveling in the left direction.

  Below, the 2nd example of the distance measuring method using the distance measuring apparatus 100 is demonstrated with reference to FIG. The flowchart in FIG. 10 is based on a processing algorithm executed by the measurement control unit 22. The distance measuring device 100 is activated when the automobile engine is started. When the engine of the automobile is started, a light emission command signal (control signal) is output from the ECU to the measurement control unit 22, and a series of processes in FIG. 10 is started. The memory of the measurement control unit 22 stores in advance a high-speed running light emission pattern HVP, a right-direction traveling light-emitting pattern RDP, and a left-direction traveling light-emitting pattern LDP, which can be set as a light-emitting pattern of the LD 10 (readable). It has become. Here, the distance measuring apparatus 100 may not have the speed acquisition unit 23.

  In the first step S21, the steering angle R of the vehicle steering is set to an initial value (0 °).

  In the next step S22, it is determined whether or not the steering angle R (acquisition result in the steering angle acquisition unit 25) is less than a threshold value + Rth1 (for example, + 15 °). If the determination in step S22 is affirmed, the process proceeds to step S23. On the other hand, if the determination in step S22 is negative, the process proceeds to step S29. Here, the rudder angle R is 0 in the straight traveling direction, + in the right direction, and-in the left direction.

  In step S23, it is determined whether the rudder angle R is larger than a threshold value −Rth1 (for example, −15 °). If the determination in step S23 is affirmative, the process proceeds to step S24. On the other hand, if the determination in step S23 is negative, the process proceeds to step S34.

  In step S24, the light emission pattern HVP for high speed running is set as the light emission pattern of the LD10.

  In the next step S25, the distance L to the object is measured and acquired. Specifically, the LD 10 is caused to emit light with the light emission pattern HVP for high-speed travel, and the distance L to the object is measured and acquired for each light emission timing of the HVP (for each range of the scanning range). Here, the object is scanned by a preset number of scans M, and the distance L is measured and acquired in each range for each scan.

  In the next step S26, the setting of the high-speed running light emission pattern HVP is canceled.

  In the next step S27, the steering angle R (acquisition result in the steering angle acquisition unit 25) is acquired.

  In the next step S28, it is determined whether or not to end the measurement. If the determination in step S28 is affirmative, the flow ends. On the other hand, if the determination in step S28 is negative, the process returns to step S22. The determination in step S28 is affirmed when the automobile engine is stopped.

  In step S29, the rightward traveling light emission pattern RDP is set as the light emission pattern of the LD10.

  In the next step S30, the distance L to the object is measured and acquired. Specifically, the LD 10 is caused to emit light with the rightward traveling light emission pattern RDP, and the distance L to the object is measured and acquired at each RDP light emission timing (for each range of the scanning range). The light emission in the rightward traveling light emission pattern RDP outputs a light emission control signal S3 corresponding to a small pulse when the ranges N1 to N3 in the scan range are scanned, and the medium pulse when the ranges N4 to N6 are scanned. Is performed by outputting a light emission control signal S2 corresponding to a large pulse when the range N7 to N12 is scanned. Here, the object is scanned by a preset number of scans M, and the distance L is measured and acquired in each range for each scan.

  In the next step S31, the setting of the rightward traveling light emission pattern RDP is canceled.

  In the next step S32, a steering angle R (acquisition result in the steering angle acquisition unit 25) is acquired.

  In the next step S33, it is determined whether or not the rudder angle R is greater than or equal to a threshold value + Rth2 (for example, + 30 °). If the determination in step S33 is negative, the process returns to step S22. On the other hand, if the determination in step S33 is affirmative, the process returns to step S29.

  As described above, when the threshold value of the steering angle R after setting the RDP is a threshold value + Rth2 larger than + Rth1, the threshold value for shifting to the HVP is changed to + Rth2 when R ≧ + Rth2. When R <+ Rth2, the threshold for shifting to HVP remains + Rth1. That is, here, the hysteresis is provided by setting two thresholds of the steering angle R that causes the light emission pattern to transition between HVP and RDP. As a result, it is possible to prevent frequent switching in the vicinity of the threshold value, and to set the threshold value according to the small steering angle and the large steering angle.

  In step S34, a left-direction light emission pattern LDP is set as the light emission pattern of the LD10.

  In the next step S35, the distance L to the object is measured and acquired. Specifically, the LD 10 is caused to emit light by the left-direction light emission pattern LDP, and the distance L to the object is measured and acquired at each light emission timing of the LDP (for each range of the scanning range). Light emission in the left-direction light emission pattern LDP is output as a light emission control signal S1 corresponding to a large pulse when the ranges N1 to N6 in the scan range are scanned, and to a medium pulse when the ranges N7 to N9 are scanned. Is performed by outputting a light emission control signal S2 corresponding to, and outputting a light emission control signal S3 corresponding to a small pulse when the range N10 to N12 is scanned. Here, the object is scanned by a preset number of scans M, and the distance L is measured and acquired in each range for each scan.

  In the next step S36, the setting of the light emission pattern LDP for leftward progress is canceled.

  In the next step S37, the rudder angle R (acquisition result in the rudder angle obtaining unit 25) is obtained.

  In the next step S38, it is determined whether or not the rudder angle R is equal to or less than a threshold value −Rth2 (for example, −30 °). If the determination in step S38 is negative, the process returns to step S22. On the other hand, if the determination in step S38 is affirmative, the process returns to step S34.

  As described above, when the threshold value of the steering angle R after setting the LDP is set to a threshold value −Rth2 smaller than −Rth1, the threshold value for shifting to the HVP is changed to −Rth2 when R ≦ −Rth2. When R> −Rth2, the threshold for shifting to HVP remains −Rth1. That is, here, hysteresis is provided by setting two threshold values of the steering angle R that causes the light emission pattern to transition between HVP and LDP. As a result, it is possible to prevent frequent switching in the vicinity of the threshold value, and to set the threshold value according to the small steering angle and the large steering angle.

  Here, the light emission pattern HRP for high speed right traveling (see FIG. 12A), the light emission pattern LRP for low speed right traveling (see FIG. 12B), which are light emission patterns based on the speed of the vehicle and the steering angle of the steering wheel, A light emission pattern HLP for fast left travel (not shown) and a light emission pattern LLP for slow left travel (not shown) may be used.

  The light emission pattern HRP for high-speed right traveling is a light emission pattern in which the amount of emitted light increases stepwise from the left end to the right end of the scanning range as shown in the lower diagram of FIG. Also in the light emission pattern HRP for high speed right traveling, the scanning range is divided into twelve ranges N1 to N12, similar to the light emission pattern HVP for high speed travel and the light emission pattern LVP for low speed travel. The first to third ranges N1 to N3 counted from the left end of the scanning range are scanned with a small pulse, and the fourth to sixth ranges N4 to N6 counted from the left end of the scanning range are scanned. The middle pulse is scanned, and the seventh to twelfth ranges N7 to N12 counted from the left end of the scanning range are scanned with large pulses. Here, the straight traveling direction of the automobile is included in the scanning range (N1 to N12). Note that the number of divisions of the scanning range is not limited to 12, but the main point is preferably 2 or more.

  The number of scans M is also set in the light emission pattern HRP for high-speed right advancing. The area shown by hatching in FIG. 12A shows the estimated stop range of the automobile according to the measurement distance and the speed of the automobile. Here, since the rudder angle is directed to the right at high speed, the estimated stop range is a narrow-angle sector that is elongated from the automobile to the right, which is the traveling direction. Further, in the upper diagram of FIG. 12A, the measurement distances corresponding to the small pulse, medium pulse, and large pulse are shown.

  By causing the LD 10 to emit light with the light emission pattern HRP for high-speed right traveling, the measurement distance in the substantially traveling direction can be increased as much as possible while traveling in the right direction at high speed, and the power consumption can be reduced.

  The slow right traveling light emission pattern LRP is a light emission pattern in which the amount of emitted light increases stepwise from the left end to the right end of the scanning range, as shown in the lower diagram of FIG. Also in the low-speed right-traveling light emission pattern LRP, the scanning range is divided into 12 ranges N1 to N12, similar to the high-speed travel light-emitting pattern HVP and the low-speed travel light-emitting pattern LVP. The first to sixth ranges N1 to N6 counted from the left end of the scanning range are scanned with small pulses, and the seventh to ninth ranges N7 to N9 counted from the left end of the scanning range are scanned. The middle pulse is scanned, and the tenth to twelfth ranges N10 to N12 counted from the left end of the scanning range are scanned with a large pulse. Here, the straight traveling direction of the automobile is included in the scanning range (N1 to N12). Note that the number of divisions of the scanning range is not limited to 12, but the main point is preferably 2 or more.

  The number M of times of scanning is set also in the light emission pattern LRP for low speed right traveling. The area indicated by hatching in FIG. 12B shows the estimated stop range of the automobile according to the measurement distance and the speed of the automobile. Here, since the rudder angle is rightward at a low speed, the estimated stop range is a fan shape with a wide range of short diameters and wide angles centering on the traveling direction from the automobile. In the upper part of FIG. 12B, measurement distances corresponding to small pulses, medium pulses, and large pulses are shown.

  By causing the LD 10 to emit light with the light emission pattern LRP for slow right traveling, the measurement range including the traveling direction can be widened while traveling in the right direction at low speed, and the power consumption can be reduced as much as possible.

  The light emission pattern HLP for high speed left traveling is a light emission pattern in which the amount of light emission increases stepwise from the right end to the left end of the scanning range, that is, the light emission pattern that is the opposite of the light emission pattern HRP for high speed right traveling. Also in the high-speed left light emission pattern HLP, similarly to the high-speed light emission pattern HVP and the low-speed light emission pattern LVP, the scanning range is divided into 12 ranges N1 to N12. The first to sixth ranges N1 to N6 counted from the left end of the scanning range are scanned with a large pulse, and the seventh to ninth ranges N7 to N9 counted from the left end of the scanning range are scanned. The middle pulse is scanned, and the tenth to twelfth ranges N10 to N12 counted from the left end of the scanning range are scanned with small pulses. Note that the number of divisions of the scanning range is not limited to 12, but the main point is preferably 2 or more.

  By causing the LD 10 to emit light with the light emission pattern HLP for high-speed left traveling, the measurement distance in the substantially traveling direction can be made as long as possible while traveling in the left direction at high speed, and the power consumption can be reduced.

  The light emission pattern LLP for low speed left traveling is a light emission pattern in which the amount of light emission increases stepwise from the right end to the left end of the scanning range, that is, the light emission pattern that is opposite to the light emission pattern LRP for low speed right traveling. Also in the low-speed left-traveling light emission pattern LLP, the scanning range is divided into 12 ranges N1 to N12, similar to the high-speed travel light-emitting pattern HVP and the low-speed travel light-emitting pattern LVP. The first to third ranges N1 to N3 counted from the left end of the scanning range are scanned with a large pulse, and the fourth to sixth ranges N4 to N6 counted from the left end of the scanning range are scanned. The middle pulse is scanned, and the seventh to twelfth ranges N7 to N12 counted from the left end of the scanning range are scanned with small pulses. Note that the number of divisions of the scanning range is not limited to 12, but is preferably 3 or more.

  By causing the LD 10 to emit light with the light emission pattern LLP for slow left traveling, the measurement range including the traveling direction can be widened while traveling in the left direction at low speed, and the power consumption can be reduced as much as possible.

  Below, the 3rd example of the distance measuring method using the distance measuring apparatus 100 is demonstrated with reference to FIG. The flowchart in FIG. 13 is based on a processing algorithm executed by the measurement control unit 22. The distance measuring device 100 is activated when the automobile engine is started. When the engine of the automobile is started, a light emission command signal (control signal) is output from the ECU to the measurement control unit 22, and a series of processes in FIG. 13 is started. The memory of the measurement control unit 22 includes a light emission pattern HVP for high speed travel, a light emission pattern LVP for low speed travel, a light emission pattern HRP for high speed right travel, a light emission pattern LRP for low speed right travel, a light emission pattern HLP for high speed left travel, and a low speed left travel. The light emission pattern LLP is stored in advance, and either one can be set (read out) as the light emission pattern of the LD 10.

  In the first step S101, the vehicle speed V is set to an initial value (0 km / h).

  In the next step S102, the steering angle R of the vehicle steering is set to an initial value (0 °).

  In the next step S103, it is determined whether or not the absolute value of the steering angle R is less than Rth (for example, 15 °). If the determination in step S103 is affirmed, the process proceeds to step S104. On the other hand, if the determination in step S103 is negative, the process proceeds to step S114.

  In step S104, it is determined whether or not the speed V is less than a threshold value Vth (for example, 30 km). If the determination in step S104 is affirmed, the process proceeds to step S105. On the other hand, if the determination in step S104 is negative, the process proceeds to step S111.

  In step S105, the light emission pattern LVP for low-speed traveling is set as the light emission pattern of the LD10.

  In the next step S106, the distance L to the object is measured and acquired. Specifically, the LD 10 is caused to emit light by the low-speed driving light emission pattern LVP, and the distance L to the object is measured and acquired at each light emission timing of the LVP (for each range of the scanning range). Here, the object is scanned by a preset number of scans M, and the distance L is measured and acquired in each range for each scan.

  In the next step S107, the setting of the low-speed running light emission pattern LVP is canceled.

  In the next step S108, the speed V (acquisition result in the speed acquisition unit 23) is acquired.

  In the next step S109, a steering angle R (acquisition result in the steering angle acquisition unit 25) is acquired.

  In the next step S110, it is determined whether or not to end the measurement. If the determination in step S110 is affirmed, the flow ends. On the other hand, if the determination in step S110 is negative, the process returns to step S103. The determination in step S110 is affirmed when the automobile engine is stopped.

  In step S111, the light emission pattern HVP for high speed running is set as the light emission pattern of the LD10.

  In the next step S112, the distance L to the object is measured and acquired. Specifically, the LD 10 is caused to emit light with the light emission pattern HVP for high-speed travel, and the distance L to the object is measured and acquired for each light emission timing of the HVP (for each range of the scanning range). Here, the object is scanned by a preset number of scans M, and the distance L is measured and acquired in each range for each scan.

  In the next step S113, the setting of the high-speed running light emission pattern HVP is canceled. When step S113 is executed, the process proceeds to step S108.

  In step S114, it is determined whether or not the rudder angle R is + Rth (for example, 15 °) or more. If the determination in step S114 is affirmed, the process proceeds to step S115. On the other hand, if the determination in step S114 is negative, the process proceeds to step S122. If the determination in step S114 is negative, R is −Rth (for example, −15 °) or less.

  In step S115, it is determined whether or not the speed V is less than a threshold value Vth (for example, 30 km). If the determination in step S115 is affirmed, the process proceeds to step S116. On the other hand, if the determination in step S115 is negative, the process proceeds to step S119.

  In step S116, the light emission pattern LRP for slow right traveling is set as the light emission pattern of the LD10.

  In the next step S117, the distance L to the object is measured and acquired. Specifically, the LD 10 is caused to emit light with the light emission pattern LRP for slow right traveling, and the distance L to the object is measured and acquired for each light emission timing of the LRP (for each range of the scanning range). Here, the object is scanned by a preset number of scans M, and the distance L is measured and acquired in each range for each scan.

  In the next step S118, the setting of the light emission pattern LRP for low speed right traveling is canceled. When step S118 is executed, the process proceeds to step S108.

  In step S119, the light emission pattern HRP for high speed right traveling is set as the light emission pattern of the LD10.

  In the next step S120, the distance L to the object is measured and acquired. Specifically, the LD 10 is caused to emit light by the light emission pattern HRP for high-speed right advancing, and the distance L to the object is measured and acquired for each light emission timing of the HRP (for each range of the scanning range). Here, the object is scanned by a preset number of scans M, and the distance L is measured and acquired in each range for each scan.

  In the next step S121, the setting of the light emission pattern HRP for high-speed right advancing is canceled. When step S121 is executed, the process proceeds to step S108.

  In step S122, it is determined whether or not the speed V is less than a threshold value Vth (for example, 30 km). If the determination in step S122 is affirmed, the process proceeds to step S123. On the other hand, if the determination in step S122 is negative, the process proceeds to step S126.

  In step S123, the low-speed left-traveling light emission pattern LLP is set as the light emission pattern of the LD10.

  In the next step S124, the distance L to the object is measured and acquired. Specifically, the LD 10 is caused to emit light by the light emission pattern LLP for low-speed left advance, and the distance L to the object is measured and acquired for each light emission timing of the LLP (for each range of the scanning range). Here, the object is scanned by a preset number of scans M, and the distance L is measured and acquired in each range for each scan.

  In the next step S125, the setting of the light emission pattern LLP for low speed left traveling is canceled. When step S125 is executed, the process proceeds to step S108.

  In step S126, the light emission pattern HLP for high speed left traveling is set as the light emission pattern of the LD10.

  In the next step S127, the distance L to the object is measured and acquired. Specifically, the LD 10 is caused to emit light by the light emission pattern HLP for high speed left traveling, and the distance L to the object is measured and acquired at each light emission timing of the HLP (for each range of the scanning range). Here, the object is scanned by a preset number of scans M, and the distance L is measured and acquired in each range for each scan.

  In the next step S128, the setting of the light emission pattern HLP for high speed left traveling is canceled. When step S128 is executed, the process proceeds to step S108.

  In FIG. 13, the order of step S101 and step S102 may be reversed.

  In FIG. 13, step S110 may be performed immediately before step S108.

  In FIG. 13, the order of step S108 and step S109 may be reversed. In this case, step S110 may be performed immediately before step S109.

  From the first viewpoint, the distance measuring apparatus 100 according to the first embodiment described above is light from an optical scanning system including the LD 10, the LD control unit 12 that controls the LD 10, and the polygon mirror 28 that deflects light from the LD 10. Is a distance measuring device that receives the reflected light from the object and measures the distance to the object, and the LD control unit 12 changes the amount of light emitted by the LD 10 within the scanning range of the optical scanning system.

  From a second viewpoint, the distance measuring apparatus 100 includes an LD 10, an LD control unit 12 that controls the LD 10, an optical scanning system that includes a polygon mirror 28 that deflects light from the LD 10, and an output from the optical scanning system. A detection system for detecting the light reflected by the object, and a measurement control unit 22 (ranging system) for measuring the distance to the object based on the emission timing at the LD 10 and the detection timing at the detection system. The LD control unit 12 changes the amount of light emitted by the LD 10 within the scanning range of the optical scanning system.

  According to the distance measuring apparatus 100, the amount of light emitted from the LD 10 can be increased in a desired measurement range within the scanning range and can be decreased in another range.

  As a result, it is possible to obtain a desired measurement distance within a desired measurement range while suppressing an increase in power consumption.

  Further, the distance measuring device 100 is mounted on a moving body (for example, an automobile), and the LD control unit 12 performs LD 10 for a first range (for example, N1 to N4 of HVP or LVP) including one end (for example, the left end) of the scanning range. For the second range (for example, N9 to N12 of HVP or LVP) including the other end (for example, the right end) of the scanning range, and the first amount between the first and second ranges in the scanning range. At least two of the light emission amounts of the LD 10 with respect to the third range (for example, N5 to N8 of HVP or LVP) are made different, and the third range includes the straight traveling direction of the moving body.

  In this case, for example, according to the movement state (speed or rudder angle) of the moving body (for example, an automobile), the amount of scanning light in the first range, the amount of scanning light in the second range, and the third range At least two of the amounts of the scanning light can be made different, and a desired measurement distance can be obtained in an appropriate measurement range according to the moving state of the moving body.

  If the first range is a range composed of N1 to N4 of HVP or LVP, the light emission quantity of the LD 10 is changed even within the first range (FIGS. 6A and 6B). )reference). When the second range is N9 to N12 of HVP or LVP, the light emission quantity of the LD 10 is changed even within the second range (see FIGS. 6A and 6B).

  Here, the first range may be a range composed of N1 and N2 of HVP and LVP. Further, the second range may be a range composed of N11 and N12 of HVP or LVP.

  The third range may be a range composed of N3 to N10 of HVP or LVP. In this case, the light emission quantity of the LD 10 is changed even within the third range.

  The distance measuring apparatus 100 further includes a speed acquisition unit 23 that acquires the speed of the moving body (for example, an automobile), and the LD control unit 12 determines the light emission amount of the LD 10 based on the acquisition result of the speed acquisition unit 23. Change.

  Specifically, the LD control unit 12 makes the light emission amount of the LD 10 for the third range smaller than the light emission amount for the first and second ranges when the acquisition result of the speed acquisition unit 23 is less than the threshold value Vth1. The LD 10 is caused to emit light with the low-speed running light emission pattern LVP, and the light emission amount of the LD 10 for the third range is larger than the light emission amount for the first and second ranges when the acquisition result in the speed acquisition unit 23 is equal to or greater than the threshold value Vth1. The LD 10 is caused to emit light by the high-speed running light emission pattern HVP.

  In this case, a desired measurement distance can be obtained within an appropriate measurement range according to the speed of the moving body.

  Also, the LD control unit 12 uses the high-speed running light emission pattern HVP when the acquisition result after the LD 10 emits light with the high-speed running light emission pattern HVP is less than another threshold Vth2 greater than the threshold Vth1 and greater than or equal to the threshold Vth1. The LD 10 is caused to emit light.

  In this case, frequent switching of the light emission pattern when the speed of the moving body is in the vicinity of the threshold value Vth1 can be prevented, and as a result, complication of control can be prevented.

  Furthermore, the LD control unit 12 causes the LD 10 to emit light with the high-speed driving light emission pattern HVP when the acquisition result in the speed acquisition unit 23 after causing the LD 10 to emit light with the high-speed driving light emission pattern HVP is equal to or greater than the threshold value Vth2.

  In this case, frequent switching of the light emission pattern when the speed of the moving body is in the vicinity of the threshold value Vth2 can be prevented, and as a result, complication of control can be prevented.

  Also, the LD control unit 12 emits the amount of light emitted by the LD 10 with respect to the first range including one end of the scanning range (for example, NDP to NDP of RDP and LDP) and the second range including the other end of the scanning range (for example, RDP and The light emission amount of the LD 10 with respect to the LDPN 7 to N 12) is made different, and the scanning range includes the straight traveling direction of the moving body.

  If the first range is a range composed of N1 to N6 of RDP or LDP and the second range is N7 to N12 of RDP or LDP, either of the first range and the second range of the LD10 The amount of emitted light is changed (see FIGS. 9A and 9B).

  In this case, for example, the light amount of the scanning light in the first range and the light amount of the scanning light in the second range can be made different according to the movement state (speed or rudder angle) of the moving body (for example, an automobile). A desired measurement distance can be obtained in an appropriate measurement range according to the moving state of the moving body.

  The moving body (for example, an automobile) has a steering device (for example, steering), the distance measuring device 100 further includes a steering angle acquisition unit 25 that acquires the steering angle of the steering device, and the LD control unit 12 Based on the acquisition result in the corner acquisition unit 25, the light emission quantity of the LD 10 is changed.

  Specifically, the LD control unit 12 performs the first operation when the rudder angle acquired by the rudder angle acquisition unit 25 faces one end side (for example, the left end side) of the scanning range with respect to the straight traveling direction of the moving body. The light emission amount of the LD 10 for the range (for example, N1 to N6 of RDP or LDP) is made larger than the light amount of the LD 10 for the second range (for example, N7 to N12 of RDP or LDP), and is acquired by the steering angle acquisition unit 25 When the steering angle is directed to the other end side (for example, the right end side) of the scanning range with respect to the straight traveling direction of the moving body, the light emission amount of the LD 10 for the second range is larger than the light emission amount of the LD 10 for the first range. To do.

  In this case, a desired measurement distance can be obtained in an appropriate measurement range according to the steering angle of the steering device.

  Further, the LD control unit 12 changes the light emission amount of the LD 10 based on the acquisition result in the steering angle acquisition unit 25 and the acquisition result in the speed acquisition unit 23.

  In this case, a desired measurement distance can be obtained in an appropriate measurement range according to the speed of the moving body and the steering angle of the steering device.

  In addition, it is possible to provide a moving body device including a moving body (for example, an automobile) and a distance measuring device 100 mounted on the moving body. This mobile body device can perform appropriate braking control (for example, automatic braking) according to the speed and traveling direction of the mobile body by the distance measuring device 100.

  The distance measurement method according to the first embodiment is a distance measurement method that uses an optical scanning system that is mounted on a moving body (for example, an automobile) and includes an LD 10 and a polygon mirror 28 that deflects light from the LD 10. Measuring the distance to the object based on the step of emitting light, the step of detecting the light deflected by the polygon mirror 28 and reflected by the object, the emission timing in the emission step and the detection timing in the detection step In the step of emitting, the amount of light emitted from the LD 10 is changed within the scanning range of the optical scanning system.

  According to this, the emitted light quantity of LD10 can be enlarged in the desired measurement range within a scanning range, and can be made small in another range.

  As a result, it is possible to obtain a desired measurement distance within a desired measurement range while suppressing an increase in power consumption.

  Further, the method further includes a step of acquiring the speed of the moving body, and in the emission step, the light emission amount of the LD 10 is changed based on the acquisition result in the acquisition step.

  In this case, a desired measurement distance can be obtained within an appropriate measurement range according to the speed of the moving body.

  The moving body further includes a step of acquiring a steering angle of the steering device, and in the emission step, the light emission amount of the LD 10 is changed based on an acquisition result in the acquisition step.

  In this case, a desired measurement distance can be obtained in an appropriate measurement range according to the steering angle of the steering device.

  The moving body includes a steering device, and further includes a step of acquiring the steering angle of the steering device and a step of acquiring the speed of the moving body. In the step of emitting, the step of acquiring the steering angle and the speed are obtained. Based on the acquisition result in the acquisition step, the amount of light emitted by the LD 10 is changed.

  In this case, a desired measurement distance can be obtained in an appropriate measurement range according to the speed of the moving body and the steering angle of the steering device.

<< Second Embodiment >>
The second embodiment of the present invention will be described below. In the second embodiment, members and the like having the same configurations and functions as those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  In the second embodiment, as shown in FIGS. 14A to 14C, the laser light emitted from the LD 10 and reflected through the coupling lens 26 is reflected by the reflection mirror 30, and deflected and reflected by the polygon mirror 28. Incident on the surface.

  FIG. 14A shows a state in which the light reflected by the reflecting mirror 30 is deflected by the polygon mirror 28 toward one end (left end, upstream end) of the scanning range. Here, light is incident on the deflecting reflection surface at an incident angle θ1.

  FIG. 14B shows a state in which the light reflected by the reflecting mirror 30 is deflected by the polygon mirror 28 toward the center of the scanning range. Here, the light is incident on the deflecting reflection surface at an incident angle θ2 (> θ1).

  FIG. 14C shows a state where the light reflected by the reflecting mirror 30 is deflected by the polygon mirror 28 toward the other end (right end, downstream end) of the scanning range. Here, light is incident on the deflecting reflection surface at an incident angle θ3 (> θ2).

  As a result, the incident angle of light on the deflecting / reflecting surface viewed from the rotation axis direction gradually increases from the left end (upstream end) to the right end (downstream end) of the scanning range.

  By the way, the light reflectance increases as the incident angle of the light on the deflecting reflecting surface viewed from the direction of the rotation axis decreases. Here, as shown in FIG. 15, the reflectance of light on the deflecting reflecting surface within the scanning range is represented by a curve that monotonously decreases from one end (−70 °) to the other end (+ 70 °) of the scanning range. The Note that the vertical axis in FIG. 15 represents the rate of decrease (%) from the maximum value when the maximum value of the reflectance is 0%.

  As described above, since the reflectance of light on the deflection reflection surface varies within the scanning range, the amount of light emitted by the LD 10 is adjusted according to this variation, that is, according to the scanning timing (light deflection direction). The distribution of the amount of scanning light in the scanning range can be made a desired distribution (including the case where there is no distribution, that is, the case where the amount of scanning light is uniform).

  During high-speed traveling, the LD 10 may emit light with a high-speed traveling light emission pattern HVP shown in the lower part of FIG.

  An area indicated by hatching in FIG. 16A shows an estimated stop range of the vehicle according to the measurement distance and the speed of the vehicle. Here, because of the high speed, the estimated stop range is a narrow-angle sector that is elongated from the automobile in a substantially straight direction (traveling direction). Further, in the upper diagram of FIG. 16A, the measurement distances corresponding to the small pulse, medium pulse, and large pulse are shown. The measurement distance of each pulse is asymmetrical due to the influence of the change in reflectance on the deflecting reflecting surface (see FIG. 15) within the scanning range.

  Further, during low-speed traveling, the LD 10 may emit light with a low-speed traveling light emission pattern LVP ′ shown in the lower diagram of FIG.

  The area shown by hatching in FIG. 16B shows the estimated stop range of the automobile according to the measurement distance and the speed of the automobile. Here, because of the low speed, the estimated stop range is a wide-angle fan shape extending widely from the vehicle including the straight direction. In the upper part of FIG. 16B, the measurement distances corresponding to the small pulse, medium pulse, and large pulse are shown.

  The low-speed running light emission pattern LVP ′ is a light emission pattern in which the amount of light emission increases stepwise from the left end to the right end of the scanning range. Even in the low-speed running light emission pattern LVP ′, the scanning range is divided into 12 ranges N1 to N12, similarly to the high-speed running light emission pattern HVP and the low-speed running light emission pattern LVP. The first to fourth ranges N1 to N4 counted from the left end of the scanning range are scanned with small pulses, and the fifth to tenth ranges N5 to N10 counted from the left end of the scanning range are scanned. Scanning with a middle pulse, the eleventh and twelfth ranges N11 and N12 counted from the left end of the scanning range are scanned with a large pulse. Here, the straight traveling direction of the automobile is included in the scanning range (N1 to N12). Note that the number of divisions of the scanning range is not limited to 12, but the main point is preferably 2 or more.

  By causing the LD 10 to emit light with the low-speed running light emission pattern LVP ′ during low-speed running, the measurement range including the traveling direction can be widened, and the power consumption can be significantly reduced. In addition, the variation in the amount of scanning light due to the change in reflectance (see FIG. 15) can be adjusted. That is, in the light emission pattern LVP ′ for low-speed traveling, the amount of light emitted from the LD 10 is scanned in consideration that the reflectance on the deflection reflection surface gradually decreases from the left end (downstream end) to the right end (upstream end) of the scanning range. The range is gradually increased from the left end to the right end of the range.

  In addition, the LD 10 is caused to emit light by the high-speed left-traveling light emission pattern HLP ′ (see FIG. 17A) while traveling in the left direction at a high speed, and the high-speed right-traveling light emission pattern HRP ′ (not used) while traveling in the right direction at a high speed The LD 10 may emit light as illustrated.

  An area indicated by hatching in FIG. 17A shows an estimated stop range of the vehicle according to the measurement distance and the speed of the vehicle. Here, since the vehicle travels in the left direction at a high speed, the estimated stop range is an elongated narrow-angle sector extending from the automobile in the left direction, which is the traveling direction. Further, in the upper diagram of FIG. 17A, measurement distances corresponding to small pulses, medium pulses, and large pulses are shown.

  The light emission pattern HLP ′ for high-speed left advance is a light emission pattern in which the amount of emitted light increases stepwise from the right end to the left end of the scanning range. Also in the light emission pattern HLP ′ for high speed left traveling, the scanning range is divided into 12 ranges N1 to N12, similarly to the light emission pattern HVP for high speed travel and the light emission pattern LVP for low speed travel. The first to fourth ranges N1 to N4 counted from the left end of the scanning range are scanned with a large pulse, and the fifth to eighth ranges N5 to N8 counted from the left end of the scanning range are scanned. The middle pulse is scanned, and the ninth to twelfth ranges N9 to N12 counted from the left end of the scanning range are scanned with small pulses. Here, the straight traveling direction of the automobile is included in the scanning range (N1 to N12). Note that the number of divisions of the scanning range is not limited to 12, but the main point is preferably 2 or more.

  The light emission pattern HRP ′ for high speed right traveling is a light emission pattern in which the amount of light emission increases stepwise from the left end to the right end of the scanning range, and is a light emission pattern that is exactly opposite to the light emission pattern HLP ′ for high speed left traveling. Also in the light emission pattern HRP ′ for high speed right traveling, the scanning range is divided into 12 ranges N1 to N12, similarly to the light emission pattern HVP for high speed travel and the light emission pattern LVP for low speed travel. The first to fourth ranges N1 to N4 counted from the left end of the scanning range are scanned with small pulses, and the fifth to eighth ranges N5 to N8 counted from the left end of the scanning range are scanned. The middle pulse is scanned, and the ninth to twelfth ranges N9 to N12 counted from the left end of the scanning range are scanned with large pulses. Here, the straight traveling direction of the automobile is included in the scanning range (N1 to N12). Note that the number of divisions of the scanning range is not limited to 12, but the main point is preferably 2 or more.

  The LD10 is caused to emit light with the high-speed left-traveling light emission pattern HLP ′ while traveling in the left direction at high speed, and the LD10 is caused to emit light with the high-speed right-traveling light emission pattern HRP ′ while traveling in the right direction at high speed. The measurement distance can be made as long as possible and the power consumption can be reduced.

  Further, the light emitting pattern RDP ′ for rightward traveling (see FIG. 17B) emits light while traveling in the right direction, and the light emitting pattern LDP ′ (not shown) for traveling in the leftward direction while LD10 is traveling in the left direction. May be emitted.

  An area indicated by hatching in FIG. 17B shows an estimated stop range of the automobile according to the measurement distance and the speed of the automobile. Here, since the vehicle travels in the right direction, the estimated stop range is a narrow, narrow-angle sector extending in the right direction, which is the traveling direction from the automobile. In the upper part of FIG. 17B, measurement distances corresponding to small pulses, medium pulses, and large pulses are shown.

  The rightward traveling light emission pattern RDP ′ is a light emission pattern in which the amount of emitted light increases stepwise from the left end to the right end of the scanning range. Also in the right-direction traveling light emission pattern RDP ′, the scanning range is divided into 12 ranges N1 to N12, similarly to the high-speed traveling light emission pattern HVP and the low-speed traveling light emission pattern LVP. The first to sixth ranges N1 to N6 counted from the left end of the scanning range are scanned with small pulses, and the seventh to twelfth ranges N7 to N12 counted from the left end of the scanning range are scanned. Scan with medium pulse. Here, the straight traveling direction of the automobile is included in the scanning range (N1 to N12). That is, a large pulse is not used in RDP ′. Note that the number of divisions of the scanning range is not limited to 12, but the main point is preferably 2 or more.

  The left direction light emission pattern LDP ′ is a light emission pattern in which the amount of emitted light increases stepwise from the right end to the left end of the scanning range, and is a light emission pattern that is the opposite of the left direction light emission pattern LDP ′. Also in the left-direction traveling light emission pattern LDP ′, the scanning range is divided into 12 ranges N1 to N12, similarly to the high-speed traveling light emission pattern HVP and the low-speed traveling light emission pattern LVP. The first to sixth ranges N1 to N6 counted from the left end of the scanning range are scanned with medium pulses, and the seventh to twelfth ranges N7 to N12 counted from the left end of the scanning range are scanned. Scan with medium pulse. Here, the straight traveling direction of the automobile is included in the scanning range (N1 to N12). Note that the number of divisions of the scanning range is not limited to 12, but the main point is preferably 2 or more.

  By making the LD10 emit light with the leftward traveling light emission pattern LDP ′ while traveling in the left direction, and by causing the LD10 to emit light with the rightward traveling light emission pattern RDP ′ while traveling in the right direction, the measurement distance in the substantially traveling direction is increased. And power consumption can be further reduced.

  In the second embodiment described above, a distance measurement method similar to the distance measurement method based on the flowcharts of FIGS. 7, 10, and 13 described in the first embodiment can be performed. Similar effects can be obtained.

  Specifically, in FIG. 7, LVP ′ may be set instead of LVP in step S3, and the setting of LVP ′ may be canceled in step S5.

  In FIG. 10, RDP ′ may be set instead of RDP in step S29, and the setting of RDP ′ may be canceled in step S31. In FIG. 10, LDP ′ may be set instead of LDP in step S34, and the setting of LDP ′ may be canceled in step S36.

  In FIG. 13, LVP ′ may be set instead of LVP in step S105, and the setting of LVP ′ may be canceled in step S107. In FIG. 13, HRP ′ may be set instead of HRP in step S119, and the setting of HRP ′ may be canceled in step S121. In FIG. 13, HLP ′ may be set instead of HLP in step S126, and the setting of HLP ′ may be canceled in step S128.

  In the second embodiment, contrary to the case shown in FIGS. 14A to 14C, the incident angle of light on the deflecting reflecting surface viewed from the rotation axis direction is one end (upstream end) of the scanning range. ) To the other end (downstream end), light may be incident on the polygon mirror 28 so as to gradually decrease. In this case, the diagram corresponding to FIG. 15 is represented by a curve that monotonously increases from one end (−70 °) to the other end (+ 70 °) of the scanning range.

  In the flowchart of FIG. 7, two threshold values for the speed V are used. However, the present invention is not limited to this, and one or three or more threshold values may be used. FIG. 18 shows a flowchart of the distance measurement method of Modification 1 in which one threshold Vth of the velocity V is used. Steps S41 to S50 in FIG. 18 individually correspond to steps S1 to S10 in FIG.

  The order of steps S46 and S47 in FIG. 18 may be reversed as in the flowchart of the distance measuring method of the second modification shown in FIG.

  Further, in the flowchart of FIG. 10, the control is performed based on the magnitude (absolute value) and the direction (sign ±) of the steering angle R. However, as in the flowchart of the distance measurement method of Modification 3 shown in FIG. 20. The control may be performed based only on the absolute value of the rudder angle R. In FIG. 20, when the absolute value of the rudder angle R is smaller than the threshold value Rth1, the high-speed driving light emission pattern HVP is used, and when the absolute value of the steering angle R is equal to or larger than the threshold value Rth1, the low-speed driving light emission pattern LVP is used. . Then, after the LVP is set in the light emission pattern, the light emission pattern is reset to LVP when the acquired absolute value of R is less than the threshold value Rth2 greater than the threshold value Rth1 and greater than or equal to the threshold value Rth1, or greater than or equal to the threshold value Rth2. The In addition, about each process and judgment of FIG. 20, description of the corresponding process and judgment of FIG. 7, FIG. 10 can be used.

  That is, in Modification 3, the LD control unit 12 sets the amount of light emitted by the LD 10 for the third range (N5 to N8) when the acquisition result (the absolute value of R) at the steering angle acquisition unit 25 is equal to or greater than the threshold value Rth1. The LD 10 is caused to emit light with the low-speed running light emission pattern LVP that is smaller than the light emission amount of the LD 10 with respect to the first range (N1 to N4) and the second range (N9 to N12), and the result obtained by the rudder angle acquisition unit 25 ( When the absolute value of R) is less than the threshold value Rth1, the LD 10 is caused to emit light with the high-speed running light emission pattern HVP that makes the emitted light amount of the LD 10 for the third range larger than the emitted light amount for the first and second ranges.

  In this case, a desired measurement distance can be obtained in an appropriate measurement range according to the steering angle of the steering device (for example, steering).

  In the third modification, the LD control unit 12 is configured such that the acquisition result (the absolute value of R) in the rudder angle acquisition unit 25 after causing the LD 10 to emit light with the low-speed driving light emission pattern LVP is greater than the threshold value Rth1. When the value is less than the threshold value Rth2 and greater than or equal to the threshold value Rth1, the LD 10 is caused to emit light by the low-speed running light emission pattern LVP.

  In this case, frequent switching of the light emission pattern when the steering angle of the steering device is in the vicinity of the threshold value Rth1 can be prevented, and as a result, complication of control can be prevented.

  Furthermore, the LD control unit 12 uses the low-speed driving light emission pattern LVP when the acquisition result (absolute value of R) in the speed acquisition unit 23 after causing the LD 10 to emit light with the low-speed driving light emission pattern LVP is greater than or equal to the threshold value Rth2. The LD 10 is caused to emit light.

  In this case, frequent switching of the light emission pattern when the steering angle of the steering device is in the vicinity of the threshold value Rth2 can be prevented, and as a result, complication of control can be prevented.

  Further, in the flowchart of FIG. 10, the control is performed based on the magnitude (absolute value) and the direction (sign ±) of the rudder angle R, but may be controlled based only on the direction (±) of the rudder angle R. . For example, when the direction of the steering angle R is + (for example, rightward), the light emission pattern RDP or RDP ′ for rightward traveling is used, and when the direction of the steering angle R is − (for example, leftward), Alternatively, LDP ′ may be used.

  Further, in the flowchart of FIG. 10, the control is performed based on the magnitude (absolute value) and the direction (sign ±) of the rudder angle R, but it may be controlled based on the direction (±) and the speed of the rudder angle R. good. For example, when the direction of the rudder angle R is + (for example, rightward) and the speed is equal to or higher than the threshold value Vth, the high-speed right traveling light emission pattern HRP or HRP ′ may be used. When the direction of the rudder angle R is − (for example, leftward) and the speed is equal to or higher than the threshold value Vth, the light emission pattern HLP or HLP ′ for high speed left traveling may be used. When the direction of the rudder angle R is + (for example, rightward) and the speed is less than the threshold value Vth, the light emission pattern LRP for low speed right traveling may be used. When the direction of the rudder angle R is − (for example, leftward) and the speed is less than the threshold value Vth, the low-speed left traveling light emission pattern LLP may be used.

  In the flowchart of FIG. 20, two threshold values for the steering angle R are used, but the present invention is not limited to this, and one or three or more threshold values may be used. FIG. 21 shows a flowchart of the distance measurement method of Modification 4 in which one threshold Rth for the steering angle R is used. Steps S81 to S90 in FIG. 21 individually correspond to steps S61 to S70 in FIG.

  The order of steps S86 and S87 in FIG. 21 may be reversed as in the flowchart of the distance measurement method of the fifth modification shown in FIG.

  In each of the above embodiments and modifications, a single LD is used as the light source, but the present invention is not limited to this. For example, an LD array in which a plurality of LDs are arranged in one or two dimensions, a VCSEL (surface emitting laser) which is a kind of semiconductor laser, a VCSEL array in which VCSELs are arranged in one or two dimensions, or a laser other than a semiconductor laser LED (light emitting diode), LED array in which a plurality of LEDs are arranged one-dimensionally or two-dimensionally, organic EL element, organic EL array in which a plurality of organic EL elements are arranged one-dimensionally or two-dimensionally, etc. good. Examples of the LD array in which a plurality of LDs are arranged one-dimensionally include a stack type LD array in which a plurality of LDs are stacked and an LD array in which a plurality of LDs are arranged horizontally.

  Moreover, the structure of the distance measuring device of each said embodiment and each modification can be changed suitably. For example, the irradiation optical system may not have a coupling lens or may have another lens. The light receiving optical system may not have a light receiving lens or may have another optical element (for example, a mirror).

  Further, the configuration of the LD control unit 12 can be changed as appropriate. For example, a configuration in which no capacitor is used in the LD driving circuit is also possible.

  In addition, the light emission pattern of the LD 10 described in the above embodiments and modifications can be changed as appropriate. At this time, it is preferable to set the number i of the LD driving circuits of the LD control unit 12 according to the number of divisions of the scanning range. For example, the number i may be increased as the number of divisions increases.

  Moreover, the distance measuring device 100 should just have at least one of the speed acquisition part 23 and the steering angle acquisition part 25 as needed.

  In each of the above-described embodiments and modifications, the automobile is described as an example of the moving body on which the distance measuring device is mounted. However, the moving body may be a vehicle other than the automobile (for example, a train), an aircraft, a ship, or the like. There may be.

  Specific numerical values (for example, threshold value, angle, time, etc.) and shape used in the above description are examples, and can be appropriately changed without departing from the gist of the present invention.

  As is apparent from the above description, the distance measuring device and the distance measuring method of the present invention are technical ideas using a so-called Time of Flight (TOF) method for measuring a reciprocating distance between an object and a moving object. It is widely used in industrial fields such as motion capture technology and rangefinders in addition to sensing. That is, the distance measuring device of the present invention does not necessarily have to be mounted on the moving body.

  10 ... LD (light source, part of optical scanning system), 12 ... LD controller (control part, part of optical scanning system), 16 ... light receiving optical system (part of detection system) 18 ... PD (detection system) 20) PD output detector (part of detection system), 22 ... Measurement controller (ranging system), 23 ... Speed acquisition unit, 25 ... Steering angle acquisition unit, 28 ... Polygon mirror (deflector, Part of the optical scanning system), 100.

Japanese Patent No. 3351696

Claims (20)

Distance measurement in which light is emitted from an optical scanning system including a light source, a control unit that controls the light source, and a deflector that deflects light from the light source, and reflected light from the object is received to measure the distance to the object In the device
The distance measuring apparatus according to claim 1, wherein the control unit changes a light emission amount of the light source within a scanning range of the optical scanning system. Mounted on mobile objects,
The control unit includes the light emission amount with respect to a first range including one end of the scan range, the light emission amount with respect to a second range including the other end of the scan range, and the first and second in the scan range. And at least two of the light emission amounts for the third range between the ranges of
The distance measuring apparatus according to claim 1, wherein the third range includes a straight traveling direction of the moving body. A speed acquisition unit for acquiring the speed of the mobile body;
The control unit is configured to make the light emission amount for the third range smaller than the light emission amount for the first and second ranges when the acquisition result of the speed acquisition unit is less than a threshold value. The light source is caused to emit light, and when the acquisition result is equal to or greater than the threshold value, the light emission amount for the third range is larger than the light emission amount for the first and second ranges. The distance measuring device according to claim 2, wherein the light source emits light.   When the acquisition result after causing the light source to emit light with the second light emission pattern is less than another threshold value greater than the threshold value and greater than or equal to the threshold value, the control unit uses the second light emission pattern to emit the light source. The distance measuring device according to claim 3, which emits light.   The control unit causes the light source to emit light with the second light emission pattern when the acquisition result after causing the light source to emit light with the second light emission pattern is equal to or greater than the another threshold value. Item 5. The distance measuring device according to Item 4. The moving body has a steering device,
A steering angle acquisition unit for acquiring a steering angle of the steering device;
The control unit is configured to reduce the light emission amount for the third range to be smaller than the light emission amount for the first and second ranges when an acquisition result of the steering angle acquisition unit is equal to or greater than a threshold value. A second light emission pattern that causes the light source to emit light in a pattern and that causes the light emission amount for the third range to be greater than the light emission amount for the first and second ranges when the acquisition result is less than the threshold value. The distance measuring device according to claim 2, wherein the light source emits light.   The control unit causes the light source to emit light with the first light emission pattern when the acquisition result after causing the light source to emit light with the first light emission pattern is less than another threshold value greater than the threshold value and greater than or equal to the threshold value. The distance measuring device according to claim 6, wherein the distance measuring device emits light.   The control unit causes the light source to emit light with the first light emission pattern when the acquisition result after causing the light source to emit light with the first light emission pattern is equal to or more than the another threshold value. The distance measuring device according to claim 7. Mounted on mobile objects,
The control unit makes the emitted light amount for the first range including one end of the scanning range different from the emitted light amount for the second range including the other end of the scanning range,
The distance measuring apparatus according to claim 1, wherein the scanning range includes a straight traveling direction of the moving body. The moving body has a steering device,
A steering angle acquisition unit for acquiring a steering angle of the steering device;
The control unit determines the amount of emitted light with respect to the first range when the rudder angle acquired by the rudder angle acquisition unit faces one end of the scanning range with respect to the rectilinear direction. The amount of emitted light with respect to the second range when the rudder angle acquired by the rudder angle acquisition unit is directed to the other end side of the scanning range with respect to the straight traveling direction. The distance measuring device according to claim 9, wherein the distance is larger than the amount of emitted light with respect to the first range. The moving body has a steering device,
A speed acquisition unit that acquires the speed of the moving body; and a steering angle acquisition unit that acquires a steering angle of the steering device;
10. The distance measuring device according to claim 2, wherein the control unit changes the light emission amount based on an acquisition result in the rudder angle acquisition unit and an acquisition result in the speed acquisition unit. An optical scanning system including a light source, a control unit for controlling the light source, and a deflector for deflecting light from the light source;
A detection system for detecting light emitted from the optical scanning system and reflected by an object;
A distance measuring system that measures the distance to the object based on the emission timing at the light source and the detection timing at the detection system, and
The distance measuring apparatus according to claim 1, wherein the control unit changes a light emission amount of the light source within a scanning range of the optical scanning system. Mounted on mobile objects,
A speed acquisition unit for acquiring the speed of the mobile body;
The distance measuring device according to claim 12, wherein the control unit changes the light emission amount based on an acquisition result of the speed acquisition unit. Mounted on a moving body having a steering device,
A steering angle acquisition unit for acquiring a steering angle of the steering device;
The distance measuring device according to claim 12, wherein the control unit changes the light emission amount based on an acquisition result obtained by the rudder angle acquisition unit. Mounted on a moving body having a steering device,
A steering angle acquisition unit that acquires the steering angle of the steering device; and a speed acquisition unit that acquires the speed of the moving body,
The distance measuring device according to claim 12, wherein the control unit changes the light emission amount based on an acquisition result in the rudder angle acquisition unit and an acquisition result in the speed acquisition unit. A moving object,
A distance measuring apparatus as described in any one of Claims 1-15 mounted in the said moving body. A distance measurement method using an optical scanning system that is mounted on a moving body and includes a light source and a deflector that deflects light from the light source,
Emitting light from the light source;
Detecting light deflected by the deflector and reflected by an object;
Measuring the distance to the object based on the emission timing in the emission step and the detection timing in the detection step, and
In the emitting step, the light emission amount of the light source is changed within a scanning range by the optical scanning system. Further comprising obtaining the speed of the moving object,
The distance measuring method according to claim 17, wherein, in the emitting step, the amount of emitted light is changed based on an acquisition result in the acquiring step. The moving body includes a steering device,
Further comprising obtaining a steering angle of the steering device;
The distance measuring method according to claim 17, wherein, in the emitting step, the amount of emitted light is changed based on an acquisition result in the acquiring step. The moving body includes a steering device,
Obtaining a rudder angle of the steering device;
Obtaining the speed of the moving body, and
The distance according to claim 17, wherein, in the step of emitting, the light emission amount is changed based on an acquisition result in the step of acquiring the rudder angle and an acquisition result in the step of acquiring the speed. Measuring method.

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