Optical distance measuring device

Abstract

The optical distance measuring device (200) comprises: a light emitting unit (40) which emits laser light (DL); a scanning unit (50) which scans the laser light emitted from the light emitting unit; a light receiving unit (60) which receives incident light; a rotation angle sensor (54) which detects the rotation angle of the scanning unit; and a control device (100) which acquires the rotation angle and outputs a driving signal to the light emitting unit, and performs correction control of either correction of the emission timing of the laser light or correction of the detection angle of distance data generated by using a light receiving signal output from the light receiving unit which receives the laser light, using a correction value determined at least based on an emission delay period from the acquisition time of the rotation angle to the emission time of the laser light.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is based on Japanese application No. 2019-161004 filed on September 4, 2019 and Japanese application No. 2020-139972 filed on August 21, 2020, and the contents thereof are cited herein. Technical Field

[0003] The present disclosure relates to an optical distance measuring device. Background Art

[0004] The following technology is known: in an optical ranging device that uses a reflector to reflect laser light emitted from a light emitting unit, a rotation angle sensor is used to obtain the rotation angle of the reflector, and a drive signal is output to the light emitting unit at each predetermined rotation angle (for example, Japanese Patent Publication No. 2011-85577).

[0005] In the conventional technology, the delay period from the time when the rotation angle of the reflection mirror is acquired to the time when the laser light is emitted is not taken into consideration. Summary of the invention

[0006] The present disclosure can be implemented as the following aspects.

[0007] According to one embodiment of the present disclosure, an optical distance measuring device (200, 200b, 200c, 200d, 200e) is provided. The optical distance measuring device comprises: a light emitting unit (40) emitting laser light (DL); a scanning unit (50) scanning the laser light emitted from the light emitting unit; a light receiving unit (60) receiving incident light; a rotation angle sensor (54) detecting the rotation angle of the scanning unit; and a control device (100, 100b, 100c, 100d, 100e) acquiring the rotation angle and outputting a drive signal to the light emitting unit, the control device using a correction value to perform correction control of either one of the timing of emitting the laser light and the angle of detection of the distance data, wherein the correction value is determined by using at least an emission delay period from the acquisition time of the rotation angle to the emission time of the laser light and a correspondence between the rotation angle of the rotation angle sensor and a detection error of the rotation angle sensor, and the distance data is generated by using a light receiving signal output from the light receiving unit receiving the laser light.

[0008] According to the optical distance measuring device of this mode, the control device uses the correction value determined by using at least the emission delay period to perform the correction of the emission timing of the laser or the correction of the detection angle of the object. Therefore, in the optical distance measuring device that generates the emission delay period, it is possible to obtain distance data after reducing the deviation between the rotation angle of the scanning unit at the timing of emitting the laser from the light emitting unit and the set rotation angle of the scanning unit at the timing of emitting the laser set in advance. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] By referring to the attached Figure 1 The above-mentioned object and other objects, features and advantages of the present disclosure will become more apparent with the following detailed description.

[0010] Figure 1 It is an explanatory diagram showing the structure of the optical distance measuring device according to the first embodiment.

[0011] Figure 2 This is an explanatory diagram schematically showing the control of the control device for adjusting the emission timing of the laser light.

[0012] Figure 3 This is an explanatory diagram showing the output timing of the drive signal and the emission timing of the laser light in a plan view using the rotation angle of the rotating unit.

[0013] Figure 4 It is an explanatory diagram showing the structure of an optical distance measuring device according to a second embodiment.

[0014] Figure 5 It is an explanatory diagram schematically showing the laser emission timing adjustment control in the second embodiment.

[0015] Figure 6 This is an explanatory diagram conceptually showing the generation start timing of the drive signal in the second embodiment using the rotation angle.

[0016] Figure 7 It is an explanatory diagram showing the structure of an optical distance measuring device according to a third embodiment.

[0017] Figure 8 It is an explanatory diagram showing the structure of an optical distance measuring device according to a fourth embodiment.

[0018] Fig. 9 This is an explanatory diagram showing a correspondence map between the rotation angle and the generation start timing of the drive signal.

[0019] Fig.10 It is an explanatory diagram showing the structure of an optical distance measuring device according to a fifth embodiment.

[0020] Fig.11 It is an explanatory diagram conceptually showing the correction value calculated by the correction value calculation unit.

[0021] Fig.12 It is an explanatory diagram showing an error of a detection angle with respect to a rotation angle detected by a rotation angle sensor. DETAILED DESCRIPTION

[0022] A. First Implementation Method:

[0023] like Figure 1 As shown, the optical distance measuring device 200 as the first embodiment of the present disclosure includes a housing 80, a light emitting unit 40, a scanning unit 50, a light receiving unit 60, and a control device 100. The light emitting unit 40, the scanning unit 50, and the light receiving unit 60 are arranged inside the housing 80 having a window 82. The window 82 is made of, for example, glass that transmits laser light. The optical distance measuring device 200 is mounted on a vehicle, for example, and is used to detect obstacles or measure the distance to the obstacles.

[0024] The light emitting unit 40 includes a laser diode as a light source, which emits laser light DL for distance measurement. The laser diode includes a semiconductor layer, and the semiconductor layer has an active layer for generating laser light inside. A driving signal is output from the driving pulse generating unit 140 described later. If it reaches the light emitting unit 40, the current flowing through the semiconductor layer causes light emission in the active layer, and the generated light is emitted as laser light DL by stimulated emission. The period from the moment when the driving signal is output to the light emitting unit 40 to the moment when the laser light DL is emitted from the light emitting unit 40 is also referred to as the second delay period. In addition to using a laser diode, the light source of the light emitting unit 40 may also use other light sources such as solid-state lasers.

[0025] The scanning unit 50 is composed of a so-called one-dimensional scanner. The scanning unit 50 includes a reflector 51, a rotating unit 52, and a rotation angle sensor 54. The laser light DL emitted from the light emitting unit 40 is reflected by the reflector 51, and is emitted to the outside of the housing 80 through the window 82. The rotating unit 52 receives a control signal from a rotation angle control unit 130 described later, and performs forward and reverse rotation with the central axis AX as the rotation axis. The laser light DL is scanned within the scanning range RA by swinging the reflector 51 fixed to the rotating unit 52.

[0026] In the present embodiment, an optical rotary encoder is used as the rotation angle sensor 54 , and the rotation angle sensor 54 generates pulse signals of the A phase, the B phase, and the Z phase for detecting the reference position of the rotating unit 52 .

[0027] The light receiving unit 60 has a plurality of pixels arranged in two dimensions. Each pixel is composed of a plurality of light receiving elements. A pixel may also be composed of one light receiving element. Each light receiving element outputs a signal corresponding to the incident intensity of the reflected light RL after the laser light DL is reflected by an object within the scanning range RA, such as an object OB. In the present embodiment, a single photon avalanche diode (SPAD) is used as the light receiving element. A PIN photodiode may also be used as the light receiving element. If light (photons) is input to each SPAD, it outputs a pulsed output signal indicating the incidence of light. If the light receiving element of the light receiving unit 60 receives the reflected light RL, it outputs a pulse signal corresponding to the light receiving state of the incident light to the control device 100.

[0028] The control device 100 includes a known microprocessor and memory. The microprocessor executes a pre-prepared program to control the rotation angle acquisition unit 110, the emission timing adjustment unit 120, the rotation angle control unit 130, the drive pulse generation unit 140, and the distance measurement unit 150.

[0029] The distance measuring unit 150 measures the distance to the object existing in the scanning range RA by using the so-called TOF (time of flight). More specifically, the distance measuring unit 150 adds the light receiving signals output by each SPAD of the light receiving unit 60 to generate a histogram, and detects the position (time) of the peak of the signal corresponding to the reflected light RL based on the generated histogram. The light emitting unit 40 may emit the laser DL multiple times, and the distance measuring unit 150 may obtain the addition results of the outputs of each SPAD multiple times, and add the addition results to generate a histogram. The distance measuring unit 150 calculates the distance to the object OB as the object using the time from the moment when the light emitting unit 40 emits the laser DL to the moment when the light receiving element of the light receiving unit 60 receives the reflected light RL. According to each detection angle within the scanning range RA, the distance data generated by the distance measuring unit 150 is obtained for each light receiving element of the light receiving unit 60 or each pixel composed of a plurality of light receiving elements, and point group data for each scan of the scanning range RA is generated.

[0030] The rotation angle control unit 130 outputs a control signal to the rotation unit 52 to rotate the rotation unit 52. In the present embodiment, the rotation angle control unit 130 rotates the rotation unit 52 forward and reversely at a predetermined constant speed.

[0031] The rotation angle acquisition unit 110 detects the pulse edge of the pulse signal of the A phase and the B phase output from the rotation angle sensor 54. The rotation angle acquisition unit 110 acquires the rotation angle of the rotating unit 52 by counting the pulse signal of the A phase and the B phase. The acquisition result of the rotation angle of the rotating unit 52 is output to the emission timing adjustment unit 120. The drive pulse generation unit 140 receives the command signal from the emission timing adjustment unit 120 and generates a drive signal for making the laser diode emit light, and outputs it to the light emitting unit 40. The period from the time when the rotation angle acquisition unit 110 detects the pulse edge to the time when the drive pulse generation unit 140 outputs the drive signal is also referred to as the first delay period.

[0032] The emission timing adjustment unit 120 performs emission timing adjustment control. The emission timing adjustment control represents the following control: in order to emit the laser DL at a preset rotation angle of the rotating unit 52, the generation of the drive signal is started by the driving pulse generating unit 140 using a correction value determined by the rotation speed of the rotating unit 52 and the emission delay period, thereby adjusting the emission timing of the laser DL. In the present embodiment, the emission delay period represents the sum of the first delay period and the second delay period. The emission delay period can also be set by the period of either the first delay period or the second delay period, or by any fixed value. In the present embodiment, as the start timing of the generation of the drive signal, the emission timing adjustment unit 120 uses the correction angle DT as a correction value pre-stored in the memory. The correction angle DT can be calculated, for example, by multiplying the emission delay period by the rotation speed of the rotating unit 52. In the present embodiment, the correction angle DT is set by a fixed value based on data stored through experiments, etc. The emission timing adjustment unit 120 may also obtain the rotation angle of the rotating unit 52 from the rotation angle acquisition unit 110, use a different correction value for each rotation angle, and use a different correction angle DT for each rotation angle. In the case where the light emitting unit 40 emits laser light DL multiple times in order to generate a histogram by adding the addition results of the outputs of each SPAD by the ranging unit 150, the correction angle DT may also be used for the start timing of generating a drive signal for emitting the first laser light DL among the multiple laser light DL emissions in generating a histogram. Regarding the start timing of generating a drive signal for emitting the second and subsequent laser light DL in generating a histogram, in addition to the correction angle DT, it may also be executed at each period predetermined according to the rotation speed of the rotating unit 52, the period for generating the histogram, etc., from the start time of generating the drive signal for emitting the first laser light DL.

[0033] use Figure 2 and Figure 3 The details of injection timing adjustment control are described below. Figure 2As shown, the rotation angle sensor 54 generates two rectangular wave pulse signals of phase A and phase B. The pulse signal of phase A and the pulse signal of phase B are outputted in a state where the phase of the pulse signal of phase A and the phase of the pulse signal of phase B are shifted by one quarter of the pitch. Figure 2 In the figure, the detection timing of the pulse edge by the rotation angle acquisition unit 110 and the timing of emitting the laser DL from the light emitting unit 40 by the input of the drive signal are conceptually represented at the lower side of the pulse signal of the A phase and the B phase. In the present embodiment, when the laser DL is emitted multiple times for generating a histogram, the timing of emitting the laser DL represents the timing of emitting the laser DL for the first time. As described later, Figure 2 The detection timing of the pulse edge shown refers to the timing of outputting a command signal for starting to generate a drive signal for emitting laser light DL at a target rotation angle to the drive pulse generator 140. The detection timing of the pulse edge by the rotation angle acquisition unit 110 is controlled by using a quarter pitch of the rectangular wave in each pulse of the A phase and the B phase as the minimum unit.

[0034] exist Figure 3 In FIG. 1 , the rotation angle of the rotating portion 52 at the timing when the rotation angle acquisition unit 110 detects the pulse edge TM1 is conceptually indicated by a dotted line. Figure 3 The solid arrows shown in FIG. 5 represent the rotation angle of the rotating portion 52 at the timing when the laser light DL is emitted from the light emitting portion 40 by the input of the driving signal. Figure 3 , as the rotation angle of the target emitting the so-called laser light DL, a set rotation angle LD1 preset in the optical distance measuring device 200 of the present embodiment is shown.

[0035] When the rotating unit 52 rotates, due to the above-mentioned emission delay period, an error occurs between the rotation angle of the rotating unit 52 at the timing when the rotation angle acquisition unit 110 detects the pulse edge and the rotation angle of the rotating unit 52 at the timing when the laser light DL is emitted from the light emitting unit 40. As described above, the error in the rotation angle is calculated by multiplying the rotation speed of the rotating unit 52 by the above-mentioned emission delay period.

[0036] like Figure 2 and Figure 3As shown, in the present embodiment, a correction angle DT1 is set as an example of the correction angle DT. The correction angle DT1 is equivalent to the difference in rotation angle between the rotation angle at the timing when the rotation angle acquisition unit 110 detects the pulse edge and the rotation angle at the timing when the laser DL is emitted. In other words, the laser DL is emitted at a timing rotated by the correction angle DT1 from the timing when the rotation angle acquisition unit 110 detects the pulse edge. The period during which the rotating unit 52 rotates the reflector 51 by the correction angle DT1 includes a first delay period from the generation of the drive signal by the drive pulse generation unit 140 to the output to the light emitting unit 40, and a second delay period from the output of the drive signal to the light emitting unit 40 to the emission of the laser DL by the light emitting unit 40. In the present embodiment, the correction angle DT1 is calculated by multiplying the rotation speed of the rotating unit 52 rotating at a constant speed predetermined by the rotation angle control unit 130 by the emission delay period as a preset value. The correction angle DT1 is, for example, Figure 2 The one shown is one quarter of the pulse signal of phase A.

[0037] like Figure 3 As shown, in the optical ranging device 200 of the present embodiment, when the pulse edge of the laser light DL emitted from the light emitting unit 40 is detected to be earlier than the preset set rotation angle LD1 by the correction angle DT1, the generation of the drive signal is started. As described above, in the present embodiment, since the rotation speed of the rotating unit 52 is a constant speed, the generation of the drive signal is started by advancing the correction angle DT1 at each rotation angle within the scanning range RA. Therefore, in the optical ranging device 200 of the present embodiment, the rotation angle of the rotating unit 52 at the time when the laser light DL is emitted from the light emitting unit 40 is consistent with the set rotation angle LD1.

[0038] As described above, according to the optical distance measuring device 200 of the present embodiment, the control device 100 controls the drive pulse generating unit 140 so as to start generating the drive signal at a timing that is earlier than the correction angle DT1 that is a correction value determined using the emission delay period. Therefore, in the optical distance measuring device 200 that generates the emission delay period, it is possible to reduce the deviation between the rotation angle of the rotating unit 52 at the timing when the laser light DL is emitted from the light emitting unit 40 and the set rotation angle LD1 of the rotating unit 52 at the preset timing when the laser light DL is emitted.

[0039] B. Second Implementation Method:

[0040] The optical distance measuring device 200b of the second embodiment sets the rotation speed of the rotating unit 52 for each of a plurality of regions divided by the rotation angle within the scanning range RA, and outputs a driving signal at a timing corresponding to the rotation speed of each region. Figure 4As shown, the optical distance measuring device 200b of the second embodiment is different from the optical distance measuring device 200 of the first embodiment in that the control device 100 is replaced with the control device 100b, and the other aspects are the same as the optical distance measuring device 200 of the first embodiment. The control device 100b is different from the control device 100 in that it further includes a timing determination unit 160.

[0041] In the present embodiment, the rotation angle control unit 130 rotates the rotating unit 52 forward and reversely by so-called single vibration. That is, the rotation speed of the rotating unit 52 is variable within the scanning range RA, and the rotation speed of the rotating unit 52 is the fastest in the center of the scanning range RA, and the rotation speed of the rotating unit 52 gradually slows down as it moves toward the end of the scanning range RA.

[0042] use Figure 5 and Figure 6 In the present embodiment, the control device 100b sequentially acquires the rotation angle of the rotating unit 52 through the rotation angle acquisition unit 110, and outputs a drive signal as a correction angle DT corresponding to each rotation angle of the rotating unit 52.

[0043] like Figure 5 As shown, in this embodiment, as the correction angle DT, the correction angle DT21, the correction angle DT22, and the correction angle DT23 are pre-stored in the memory. In this embodiment, the correction angles DT21 to DT23 are set for each area divided in the scanning range RA. The scanning range RA is divided into three areas RA1 to RA3 corresponding to the rotation speed of the rotating unit 52. The setting of the areas RA1 to RA3 is preferably divided according to each change point of the rotation speed of the rotating unit 52. For the convenience of explanation, in Figure 5 and Figure 6 RA1 to RA3 are conceptually shown in FIG. The rotation speed of the rotating unit 52 is slowest in the region RA1 and fastest in the region RA3. The scanning range RA is not limited to three regions, but may be divided into any number of regions corresponding to the change in the rotation speed of the rotating unit 52, such as five or ten regions.

[0044] The correction angles DT21 to DT23 are set using the average value of the rotation speed of the rotating part 52 in each of the regions RA1 to RA3 and the injection delay period. The correction angle DT21 is, for example, a quarter pitch of the pulse signal of the A phase. The correction angle DT22 is, for example, a half pitch of the pulse signal of the A phase. The correction angle DT23 is, for example, a three-quarter pitch of the pulse signal of the A phase. The correction angles DT21 to DT23 may also be set using the maximum value of the rotation speed of the rotating part 52 in each of the regions RA1 to RA3 and the injection delay period.

[0045] exist Figure 6 In FIG. 1 , the rotation angle of the rotating unit 52 at the timing when the rotation angle acquisition unit 110 detects the pulse edge TM2 is conceptually indicated by a dotted line. Figure 6 The solid arrows shown in FIG. 5 represent the rotation angle of the rotating portion 52 at the timing when the laser light DL is emitted from the light emitting portion 40 by the input of the driving signal. Figure 6 , the rotation angle of the target from which the laser light DL is emitted represents the set rotation angle LD2 that is preset in the optical distance measuring device 200b of the present embodiment.

[0046] The emission timing adjustment unit 120 acquires the rotation angle from the rotation angle acquisition unit 110, and determines which of the regions RA1 to RA3 it is based on the acquired rotation angle. The emission timing adjustment unit 120 reads out any one of the correction angles DT21 to DT23 corresponding to each determined region. The emission timing adjustment unit 120 starts generating a drive signal at the moment of detecting a pulse edge that is ahead of the timing of any one of the correction angles DT21 to DT23 read out. According to the optical ranging device 200b of this embodiment, by using the correction angles DT21 to DT23 as correction values ​​corresponding to the regions RA1 to RA3 with different rotation speeds, the deviation between the rotation angle of the rotating unit 52 at the moment when the laser light DL is emitted from the light emitting unit 40 and the set rotation angle LD2 for each of the regions RA1 to RA3 is reduced.

[0047] As described above, according to the optical ranging device 200b of this embodiment, the control device 100b obtains the rotation angle of the rotating unit 52, and starts generating the drive signal at the timing corresponding to the rotation speed of each rotation angle. Therefore, even in the optical ranging device 200b in which the rotation speed of the rotating unit 52 changes, the deviation between the rotation angle of the rotating unit 52 at the time when the laser light DL is emitted from the light emitting unit 40 and the set rotation angle LD2 can be reduced.

[0048] According to the optical ranging device 200b of this embodiment, the rotation speed of the rotating unit 52 is set for each of the multiple areas divided by the rotation angle, that is, the areas RA1 to RA3, and the generation of the drive signal is started at the timing corresponding to the rotation speed of each area. By a simple method of simplifying the calculation of the rotation speed of the rotating unit 52, the deviation between the rotation angle of the rotating unit 52 and the set rotation angle LD2 at the time when the laser light DL is emitted from the light emitting unit 40 can be reduced.

[0049] C. Third Implementation Method:

[0050] In the optical distance measuring device 200c of the third embodiment, the rotation speed is calculated for each predetermined rotation angle of the rotating unit 52, and the timing for starting the generation of the drive signal is calculated for each rotation angle using the calculated rotation speed and the emission delay period. Figure 7 As shown, the optical distance measuring device 200c of the third embodiment is different from the optical distance measuring device 200 of the first embodiment in that the control device 100 is replaced with the control device 100c, and the other aspects are the same as the optical distance measuring device 200 of the first embodiment. The control device 100c is different from the control device 100 in that it further includes a timing determination unit 160 and a rotation speed calculation unit 170.

[0051] In this embodiment, similarly to the second embodiment, the rotation angle control unit 130 rotates the rotating unit 52 forward and reversely by so-called single vibration. The rotation speed calculation unit 170 acquires the rotation angle of the rotating unit 52 from the rotation angle acquisition unit 110 at each predetermined unit time, and calculates the rotation speed of the rotating unit 52 based on the change in the rotation angle at each unit time. The calculation result of the rotation speed of the rotating unit 52 by the rotation speed calculation unit 170 is output to the timing determination unit 160.

[0052] The timing determination unit 160 calculates a correction angle as a correction value for each rotation angle using the calculation result of the rotation speed of the rotating unit 52 and the injection delay period. More specifically, the correction angle calculated by multiplying the rotation speed of the rotating unit 52 and the injection delay period is output to the injection timing adjustment unit 120 for each rotation angle. The injection timing adjustment unit 120 starts generating a drive signal when a pulse edge that is earlier than the timing of the correction angle calculated for each rotation angle of the rotating unit 52 is detected.

[0053] According to the optical ranging device 200c of this embodiment, the rotation speed of the rotating unit 52 is calculated according to each rotation angle of the rotating unit 52 determined in advance. The correction angle for each rotation angle of the rotating unit 52 is calculated using the calculated rotation speed of the rotating unit 52 and the emission delay period, and the generation of the drive signal is started at the timing of the correction angle calculated in advance. By using the correction angle that follows the rotation speed of the rotating unit 52, the deviation between the rotation angle of the rotating unit 52 and the set rotation angle at the timing of emitting the laser DL from the light emitting unit 40 can be further reduced.

[0054] D. Fourth Implementation Method:

[0055] The optical distance measuring device 200d of the fourth embodiment uses the timing map TM to perform emission timing adjustment control. Figure 8 As shown, the optical ranging device 200d of the fourth embodiment is different from the optical ranging device 200 of the first embodiment in that the control device 100 is replaced with the control device 100d, and the other aspects are the same as the optical ranging device 200 of the first embodiment. The control device 100d is different from the control device 100 in that the timing map TM is pre-stored in the memory instead of the correction angle DT.

[0056] The timing map TM is a correspondence map showing the correspondence relationship between the rotation angle of the rotating unit 52 and the correction angle as the correction value. Fig. 9 As shown in the timing map TM, the correction angle DD is set for each rotation angle of the scanning range RA. For example, the correction angle DD is set in advance using the actual measured value of the rotation speed of the rotating unit 52 at each rotation angle obtained in advance through experiments, etc., the actual measured value of the emission delay period obtained in advance through experiments, etc. The correction angle DD may also be set using the actual value of the rotation speed and the emission delay period stored through the use of the optical distance measuring device 200d, etc.

[0057] When the rotation angle of the rotating unit 52 is input from the rotation angle acquisition unit 110, the emission timing adjustment unit 120 determines the correction angle DD corresponding to the input rotation angle using the timing map TM. The emission timing adjustment unit 120 controls the drive pulse generation unit 140 so that the generation of the drive signal is started when a pulse edge that is ahead of the timing of the determined correction angle DD is detected.

[0058] According to the optical distance measuring device 200d of the present embodiment, the control device 100d includes a timing map TM indicating the correspondence between the rotation angle of the rotating unit 52 and the correction angle DD as a correction value. The emission timing adjustment unit 120 uses the timing map TM to determine the correction angle DD based on the rotation speed of the rotating unit 52 sequentially acquired from the rotation angle acquisition unit 110. Therefore, the deviation between the rotation angle of the rotating unit 52 and the set rotation angle at the timing of emitting the laser light DL from the light emitting unit 40 can be reduced by a simple method without causing the control device 100d to perform complicated calculations.

[0059] E. Fifth Implementation Method:

[0060] Reference Figures 10 to 12 The structure of the optical distance measuring device 200e of the fifth embodiment is described. The optical distance measuring device 200e of the fifth embodiment uses the correction value calculated using the emission delay period, etc. to correct the distance data calculated by the distance measuring unit 150. Fig.10 As shown, the optical distance measuring device 200e is different from the optical distance measuring device 200 of the first embodiment in that the control device 100 is replaced with the control device 100e, and the other aspects are the same. The control device 100e is different from the control device 100 in that the rotation speed calculation unit 115, the laser center calculation unit 180, the correction value calculation unit 190, and the distance data correction unit 155 are replaced with the emission timing adjustment unit 120.

[0061] The rotation speed calculation unit 115 calculates the rotation speed of the rotating unit 52 using the rotation angle obtained from the rotation angle acquisition unit 110. When a plurality of lasers DL are emitted at a timing for one pulse detection, the laser center calculation unit 180 calculates the center position of the plurality of lasers DL and outputs it to the correction value calculation unit 190 as the laser center correction value Z3. The correction value calculation unit 190 calculates the correction value for correcting the detection angle of the distance data. In the present embodiment, the correction value calculation unit 190 calculates the correction value using the rotation angle sensor correction value Z1, the CPU processing correction value Z2, the laser center correction value Z3, and the emission delay period Z4. The distance data correction unit 155 uses the correction value input from the correction value calculation unit 190 to correct the detection angle of each point group data obtained from the distance measuring unit 150.

[0062] Reference Fig.11 and Fig.12 , the correction value calculated by the correction value calculation unit 190 is explained. Fig.11, conceptually showing a pulse edge TM11 as an example detected by the rotation angle acquisition unit 110 , an output timing TM13 of a drive pulse generated based on the detection of the pulse edge TM11 , and emission timings LD51 to LD55 of a plurality of laser beams emitted by the drive pulse at the output timing TM13 . Fig.11 The pulse edge TM12 shown corresponds to the rotation angle of the output of the laser light next to the pulse edge TM11.

[0063] The rotation speed calculation unit 115 calculates the rotation speed of the rotating unit 52 at the detection time of the pulse edge TM12 using, for example, the rotation angle from the pulse edge TM11 to the pulse edge TM12 acquired from the rotation angle acquisition unit 110 and the period from the detection time of the pulse edge TM11 to the detection time of the pulse edge TM12. The calculation result of the rotation speed of the rotating unit 52 for each pulse edge by the rotation speed calculation unit 115 is output to the correction value calculation unit 190.

[0064] exist Fig.11 , the rotation angle sensor correction value Z1, the CPU processing correction value Z2, the laser center correction value Z3, and the emission delay period Z4 are conceptually shown. The emission delay period Z4 is stored in the memory of the control device 100e as a preset fixed value.

[0065] The rotation angle sensor correction value Z1 is a correction value for correcting the mechanical error of the output timing of the pulse signal in the rotation angle sensor 54. The rotation angle sensor 54 may be affected by, for example, the manufacturing deviation of the slit interval of the disk in the rotation angle sensor 54, the deviation of the configuration position when the rotation angle sensor 54 is installed in the housing 80, etc., and may sometimes cause an error in the detection angle. Fig.12 An example of the correspondence between the rotation angle detected by the rotation angle sensor 54 and the error amount of the detected angle is shown in FIG. Fig.12 As shown in FIG. 1 , the error of the detection angle of the rotation angle sensor 54 varies for each rotation angle. Fig.12 As shown, for example, when the optical distance measuring device 200e is provided with the rotation angle sensor 54, the corresponding relationship between the rotation angle and the error of the detection angle of the rotation angle sensor 54 can be obtained by performing an experiment to compare the detection result within the scanning range RA of the rotation angle sensor 54 with the rotation angle of the rotating part 52. The rotation angle sensor correction value Z1 is equivalent to Fig.12 The error amount of the detection angle of the rotation angle sensor 54 shown is stored in the memory of the control device 100e as a correspondence map.

[0066] The CPU processing correction value Z2 is a correction value for correcting the error in the processing period of the microprocessor of the control device 100e. The CPU processing correction value Z2 differs according to the processing power of the microprocessor. From the time when the microprocessor detects the rotation angle that becomes the output timing of the laser until the generation of the drive pulse is completed, a deviation in the processing period sometimes occurs due to reasons such as the execution of other controls. The microprocessor of the control device 100e uses an internal clock to obtain the period from the detection of the rotation angle to the completion of the drive pulse generation, and outputs it to the correction value calculation unit 190. The correction value calculation unit 190 calculates the difference between the processing period obtained from the microprocessor and the predetermined benchmark processing period of the microprocessor, and calculates the CPU processing correction value Z2 that corrects the difference.

[0067] The laser center correction value Z3 refers to a correction value for setting the central value of the emission period of the plurality of lasers DL as the emission timing of the laser DL when a plurality of lasers DL are emitted for the pulse edge TM11. The central value refers to the central value of the period until the emission of all the lasers DL is completed. In the present embodiment, the central value is equivalent to a period of half the period from the emission timing LD51 of the initial laser DL to the emission timing LD55 of the final laser. In the present embodiment, the central value is consistent with the emission timing LD53 of the third laser DL. When a plurality of lasers DL are emitted for a pulse edge TM11, the plurality of lasers DL are emitted while being scanned by the rotating portion 52. Therefore, when a point group data is generated based on a plurality of lasers DL, the plurality of lasers DL can be processed as a single laser DL having a width corresponding to the number of times the lasers DL are emitted from the central value toward both sides. The laser center calculation unit 180 calculates the laser center correction value Z3 using the rotation speed obtained from the rotation speed calculation unit 115 and the number of times the laser light DL is emitted obtained from the drive pulse generation unit 140 , for example, using the following equation (1).

[0068] Z3=V1·T1·(N1-1) / 2···Formula (1)

[0069] V1: Rotation speed of the rotating unit 52

[0070] T1: period from the emission timing LD51 of the first laser beam DL to the emission timing LD55 of the last laser beam DL

[0071] N1: Number of times the laser DL is emitted

[0072] The period T1 from the emission timing LD51 of the first laser light DL to the emission timing LD55 of the last laser light DL may be a theoretical value, or may be calculated by adding the output timings of the respective laser lights DL from the drive pulse generating unit 140 .

[0073] The correction value calculation unit 190 outputs a period obtained by multiplying the total period obtained by adding the rotation angle sensor correction value Z1, the CPU processing correction value Z2, the laser center correction value Z3, and the emission delay period Z4 by the rotation speed of the rotating unit 52 obtained from the rotation speed calculation unit 115 as a correction value to the distance data correction unit 155. The distance data correction unit 155 uses the correction value obtained from the correction value calculation unit 190 to correct the detection angle of the point group data corresponding to the pulse edge TM11.

[0074] According to the optical distance measuring device 200e of the present embodiment, the control device 100e uses the correction value determined by the emission delay period Z4, etc. to perform correction of the detection angle of the point group data generated by the distance measuring unit 150. Without controlling the light emitting unit 40, distance data with reduced deviation of the detection angle in the distance data can be obtained with a simple structure.

[0075] According to the optical distance measuring device 200e of this embodiment, the control device 100e determines the correction value using the detection error of the rotation angle sensor 54. By eliminating the detection error of the rotation angle by the rotation angle sensor 54, the deviation of the detection angle in the distance data can be further reduced.

[0076] According to the optical distance measuring device 200e of this embodiment, the control device 100 uses the central value from the emission timing LD51 of the initial laser DL to the emission timing LD55 of the final laser DL to determine when emitting multiple lasers DL for the detected pulse edge TM11. Therefore, the detection angle in the distance data when generating a point group data based on multiple lasers DL can be corrected to a more appropriate value.

[0077] F. Other implementation methods:

[0078] (F1) In the first embodiment described above, one correction angle DT calculated using the rotation speed of the rotating portion 52 rotating at a constant speed and the emission delay period is set. In contrast, one correction angle DT may be set for the rotating portion 52 whose rotation speed varies, such as the rotating portion 52 rotating forward and reverse by a single vibration. Even in the optical distance measuring device of this type, the deviation between the rotation angle of the rotating portion 52 at the time when the laser light DL is emitted from the light emitting portion 40 and the set rotation angle LD1 can be reduced. In addition, the correction angle DT may be calculated using the intermediate value between the maximum value and the minimum value of the rotation speed of the rotating portion 52 within the scanning range RA of the rotating portion 52. Thus, the deviation between the rotation angle of the rotating portion 52 at the timing when the laser light DL is emitted from the light emitting portion 40 and the set rotation angle can be reduced by a simple method without causing the control device 100 to perform complicated calculations. The correction angle DT may also be calculated using the average value of the emission delay period and the rotation speed of the rotating portion 52 within the scanning range RA of the rotating portion 52.

[0079] (F2) In the above-mentioned embodiments, the rotation angle sensor 54 may be a magnetic type instead of an optical type, or an absolute type instead of an incremental type. A circuit that generates a clock signal may be used instead of the rotation angle sensor 54 .

[0080] (F3) In the above-mentioned embodiments, an example is shown in which the optical ranging device is provided with a control device, but the control device may also be provided in a vehicle provided with the optical ranging device. For example, the vehicle may also be provided with a distance data correction unit 155 and a correction value calculation unit 190, etc., or a part of the function of the control device may be provided in the vehicle. By configuring in this way, the optical ranging device can be made lighter.

[0081] (F4) In the fifth embodiment, the control device 100e is shown as an example in which the control device 100e does not include the emission timing adjustment unit 120, but the control device 100e may include the emission timing adjustment unit 120. In this case, the emission timing adjustment unit 120 may control the drive pulse generation unit 140 so as to start generating the drive signal at a timing that is earlier than the timing of the correction value obtained from the correction value calculation unit 190.

[0082] The control unit and method thereof described in the present disclosure may also be implemented by a special-purpose computer, which is provided by constituting a processor and a memory programmed to execute one or more functions embodied by a computer program. Alternatively, the control unit and method thereof described in the present disclosure may also be implemented by a special-purpose computer, which is provided by constituting a processor composed of one or more special-purpose hardware logic circuits. Alternatively, the control unit and method thereof described in the present disclosure may also be implemented by one or more special-purpose computers, which are constituted by a combination of a processor and a memory programmed to execute one or more functions and a processor composed of one or more hardware logic circuits. In addition, a computer program may also be stored as an instruction executed by a computer in a non-migratable tangible recording medium that can be read by a computer.

[0083] The present disclosure is not limited to the above-mentioned embodiments, and can be implemented in various structures within the scope of its main purpose. For example, in order to solve part or all of the above-mentioned problems, or to achieve part or all of the above-mentioned effects, the technical features in the embodiments corresponding to the technical features recorded in the part of the invention content can be appropriately replaced or combined. In addition, if the technical feature is not described as a necessary content in this specification, it can be appropriately deleted.

Claims

1. An optical distance measuring device, comprising: a light emitting portion that emits laser light; a scanning unit configured to scan the laser light emitted from the light emitting unit; a light receiving portion that receives incident light; a rotation angle sensor that detects a rotation angle of the scanning unit; and A control device that obtains the rotation angle and outputs a drive signal to the light emitting unit, wherein the control device uses a correction value to perform correction control of either the emission timing of the laser or the detection angle of the distance data, wherein: The correction value is determined by using at least an emission delay period from the acquisition time of the rotation angle to the emission time of the laser and a correspondence between the rotation angle detected by the rotation angle sensor and a detection error of the rotation angle sensor, and the distance data is generated by using a light receiving signal output from the light receiving unit that receives the laser. The control device calculates the correction value corresponding to the rotation speed of the scanning unit at each of the rotation angles.

2. The optical distance measuring device according to claim 1, wherein: When a plurality of laser beams are emitted for the acquired one rotation angle, the control device further determines the correction value using a half period from the emission timing of the first laser beam to the emission timing of the last laser beam.

3. The optical distance measuring device according to claim 1, wherein: The control device sets the rotation speed of the scanning unit for each of the plurality of areas divided by the rotation angle. The control device calculates the correction value using the set rotation speed of the scanning section for each of the plurality of areas.

4. The optical distance measuring device according to claim 1, wherein: The control device calculates the rotation speed of the scanning unit according to each of the predetermined rotation angles. The control device calculates the correction value for each of the rotation angles using the calculated rotation speed of the scanning unit.

5. The optical distance measuring device according to any one of claims 1 to 4, wherein: The control device uses a correspondence map indicating a correspondence relationship between the rotation angle and the correction value.

6. An optical distance measuring device, comprising: a light emitting portion that emits laser light; a scanning unit configured to scan the laser light emitted from the light emitting unit; a light receiving portion that receives incident light; a rotation angle sensor that detects a rotation angle of the scanning unit; and A control device that obtains the rotation angle and outputs a drive signal to the light emitting unit, wherein the control device uses a correction value to perform correction control of either the emission timing of the laser or the detection angle of the distance data, wherein: The correction value is determined by using at least an emission delay period from the acquisition time of the rotation angle to the emission time of the laser and a correspondence between the rotation angle detected by the rotation angle sensor and a detection error of the rotation angle sensor, and the distance data is generated by using a light receiving signal output from the light receiving unit that receives the laser. The control device calculates the correction value using an intermediate value between a maximum value and a minimum value of the rotation speed of the scanning unit within a scanning range.

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