JP6906919B2 - Detection device, control method and program - Google Patents

Description

The present invention relates to an injection control technique for an optical pulse for measurement.

Conventionally, a technique for measuring the distance to an object existing in the vicinity has been known. For example, Patent Document 1 discloses an in-vehicle system equipped with a rider that detects a point cloud on the surface of an object by scanning a horizontal direction while intermittently emitting a laser beam and receiving the reflected light. There is.

Japanese Unexamined Patent Publication No. 2014-86991

When capturing landmarks in the surrounding environment using a rider, if the landmarks contained in the scanning surface are relatively small with respect to the scanning angle resolution, such as when the landmarks are far away, The number of measurement points corresponding to the landmark may be excessively reduced, and the shape of the landmark may not be recognized correctly. As described above, in the conventional rider, since light is emitted with a constant scanning angle resolution with a constant light intensity, it may not be possible to accurately detect surrounding objects.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a detection device capable of suitably detecting an object around a moving body.

The invention according to claim 1 is a detection device that can be arranged on a moving body, in which an emitting unit that emits light, a light receiving unit that receives the light reflected by an object, and the emitting unit emit light. and a control unit for controlling at least one of the intensity and injection frequency of light, and wherein, when the lane adjacent to the sidewalk mobile traveling, on the side of the side to which the walkway is present The frequency with which the intensity of the emitted light is controlled to be higher than the intensity of the emitted light to the opposite side, or the frequency with which the light is emitted to the side where the sidewalk exists is determined. It is controlled so as to be higher than the frequency at which the light is emitted to the opposite side.

The invention according to claim 8 is a control method executed by a detection device that has an injection unit that emits light and a light receiving unit that receives the light reflected by an object and can be arranged on a moving body. The control step includes a control step of controlling at least one of the intensity of light emitted by the injection unit and the frequency of emission, and the control step is the sidewalk when a moving body is traveling in a lane adjacent to the sidewalk. the intensity of the light but that emitted to the side of the present side, is controlled to be higher than the intensity of light emitted to the side opposite, or, the laterally on the side where the sidewalk is present The frequency of light emission is controlled to be higher than the frequency of light emission to the opposite side.

The invention according to claim 9 is a program executed by a computer of a detection device having a light emitting unit that emits light and a light receiving unit that receives the light reflected by an object and can be arranged on a moving body. The computer functions as a control unit that controls at least one of the intensity of light emitted by the injection unit and the frequency of emission, and the control unit is used when a moving body is traveling in a lane adjacent to a sidewalk. In addition, the intensity of the light emitted to the side where the sidewalk is present is controlled to be higher than the intensity of the light emitted to the side on the opposite side, or the side where the sidewalk is present. frequency of the light to the side is emitted is, the light is controlled to be higher than the frequency emitted to the side of the opposite side.

The schematic configuration of the object detection system according to the Example is shown. The overall configuration of the rider according to the embodiment is shown. The configuration of the transmitter and the receiver is shown. The configuration of the scanning optical unit is shown. An example of register setting of the control signal generated by the synchronous control unit is shown. The temporal relationship of the control signal generated by the synchronous control unit is shown. It is a graph which shows the relationship between the ADC output signal and a gate. The time relationship of the pulse train of the rotary encoder is shown. The time relationship between the encoder pulse and the segment slot in the steady state is shown. It is a block diagram of signal processing by DSP. It is a top view around the vehicle which roughly showed the emission power and scanning angle resolution of the emission light in 360 degree scanning in the 1st control mode by the broken line arrow. It is a top view around the vehicle which roughly showed the emission power and scanning angle resolution of the emission light in 360 degree scanning in the 2nd control mode by the broken line arrow. It is a top view around the vehicle which roughly showed the emission power and scanning angle resolution of the emission light in the 360 degree scanning in the 3rd control mode by the broken line arrow. It is a top view around the vehicle which shows the emission power and the scanning angle resolution of the emission light in the scanning of 360 degrees in the 4th control mode by the broken line arrow.

In one preferred embodiment of the present invention, a detection device that can be placed on a moving body, the emitting portion that emits light, the light receiving portion that receives the light reflected by the object, and the moving body. It includes a first acquisition unit that acquires position information indicating a position, and a control unit that controls at least one of the intensity of light emitted by the emission unit and the frequency of emission based on the position information.

The detection device includes an injection unit that emits light, a light receiving unit that receives light reflected by an object, a first acquisition unit, and a control unit. The first acquisition unit acquires position information indicating the position of the moving body. The control unit controls at least one of the intensity of the light emitted by the injection unit and the frequency of emission based on the position information acquired by the first acquisition unit. According to this aspect, the detection device can preferably detect an object to be preferentially detected according to the position of the moving body.

In one aspect of the detection device, the detection device further includes a second acquisition unit that acquires route information regarding the movement path of the moving body, and the control unit further includes the injection based on the position information and the route information. It controls at least one of the intensity of the light emitted by the unit and the frequency of emission. In general, the direction in which an object to be preferentially detected exists differs depending on the moving route (for example, whether it is a right-turning route or a left-turning route). Therefore, according to this aspect, the detection device can preferably detect an object existing in a direction having a high priority to be detected in consideration of the movement path of the moving body.

In another aspect of the detection device, the control unit controls the injection unit so that the intensity of light and the frequency of emission differ between the front side and the side of the moving body. According to this aspect, an object existing in a direction having a high priority to be detected can be suitably detected.

In another aspect of the detection device, the control unit controls the front of the moving body so that the light intensity is high and the emission frequency is low with respect to the side of the moving body. As a result, the detection device can detect obstacles and the like in front of the moving body at an early stage while satisfying the criteria of eye safety.

In another aspect of the detection device, in the control unit, when a sidewalk is present on the side of the moving body, the intensity of the light on the side where the sidewalk is present is on the opposite side. It is controlled to be higher than the above. According to this aspect, the detection device can suitably detect an object (for example, a pedestrian, etc.) existing on the sidewalk side, which requires special attention during driving.

In another aspect of the detection device, when the sidewalk exists on the side of the moving body, the control unit emits the light on the side where the sidewalk exists on the opposite side. Control so that it is higher than the side of. According to this aspect, it is possible to suitably detect an object (for example, a pedestrian) existing on the sidewalk side, which requires special attention during driving. Further, according to this aspect, the detection device can suitably detect a feature having a thin shape such as a kilometer post or a signboard.

In another aspect of the detection device, when the moving body makes a right turn, the control unit emits the light having a high intensity of light with respect to the front right side of the moving body and the other. Control so that it is done less frequently. According to this aspect, the detection device can detect an oncoming vehicle traveling at high speed toward the right turn point at an early stage when the moving body makes a right turn.

In another aspect of the detection device, when the moving body makes a left turn, the control unit has a frequency at which the left side of the moving body has a weaker light intensity and the light is emitted from the other side. Is controlled to increase. According to this aspect, the detection device can accurately detect pedestrians, motorcycles, and the like that may get caught when the moving body turns left.

In another preferred embodiment of the present invention, a detection device that can be arranged on a moving body, the emitting portion that emits light, the light receiving portion that receives the light reflected by the object, and the moving body. The intensity of the light emitted by the injection portion in the front is higher than the intensity of the light emitted by the injection portion on the side of the moving body, and the emission frequency of the injection portion in the front is on the side. A control unit for controlling the injection unit is provided so as to be less than the injection frequency. According to this aspect, the detection device can detect obstacles and the like in front of the moving body at an early stage while satisfying the criteria of eye safety.

In another preferred embodiment of the present invention, a control executed by a detection device having an injection unit that emits light and a light receiving unit that receives the light reflected by an object and can be arranged on a moving body. A method of controlling at least one of a first acquisition step of acquiring position information indicating the position of the moving body and at least one of the intensity of light emitted by the injection unit and the frequency of injection based on the position information. It has a process. By executing this control method, the detection device can preferably detect an object to be preferentially detected according to the position of the moving body.

In another preferred embodiment of the present invention, a computer of a detection device having a light emitting part that emits light and a light receiving part that receives the light reflected by an object and can be arranged on a moving body is executed. A first acquisition unit that acquires position information indicating the position of the moving body, and controls at least one of the intensity of light emitted by the injection unit and the frequency of emission based on the position information. The computer functions as a control unit. By executing this program on a computer, the above-mentioned detection device can be realized. This program can be stored and handled in a storage medium.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

[Overview of object detection system]
FIG. 1 is a schematic configuration of an object detection system according to this embodiment. The object detection system includes a lidar (Light Detection and Ranking) 1 that moves with the vehicle, and an in-vehicle device 2 that can communicate with the lidar 1.

The rider 1 emits a pulsed laser to a predetermined angle range in the horizontal and vertical directions to discretely measure the distance to an object existing in the outside world, and a three-dimensional point indicating the position of the object. Group information is generated and supplied to the in-vehicle device 2. In this embodiment, the rider 1 receives the current position information, the map information, and the route information from the in-vehicle device 2 to set the emission power and the emission interval (that is, the emission frequency or the scanning angle resolution) of the pulse laser for each direction. Change. The rider 1 is an example of the "detector" in the present invention.

The in-vehicle device 2 detects an object around the vehicle based on the point cloud information output by the rider 1, controls the vehicle for driving support (including automatic driving), and outputs a predetermined display or voice. I go. In this embodiment, the vehicle-mounted device 2 supplies the current position information “IP”, the map information “IM”, and the route information “IR” to the rider 1. Here, the on-board unit 2 may transmit the position information output by the GPS receiver or the like to the rider 1 as the current position information IP, and the known self-position estimation process using the output of the rider 1 or another external sensor. The position information estimated by the above may be transmitted to the rider 1 as the current position information IP. Further, the vehicle-mounted device 2 transmits, for example, the map information around the current position extracted from the map database to the rider 1 as the map information IM. Further, the vehicle-mounted device 2 transmits the information regarding the route to the set destination to the rider 1 as the route information IR.

The configuration of FIG. 1 is an example, and the configuration to which the present invention can be applied is not limited to this. For example, instead of receiving the map information IM from the in-vehicle device 1, the rider 1 may receive the map information IM from a server device (not shown) that stores the map database via the network. In another example, instead of receiving the current position information IP from the in-vehicle device 1, the rider 1 may generate the current position information IP by itself by providing a GPS receiver or the like, and the rider 1 generates the current position information IP. The current position information IP may be generated by performing self-position estimation based on point cloud information or the like. Further, the route information IR here is typically information on a route to a destination set by the vehicle-mounted device 2, but is not limited to this. For example, in addition to the information set by the user of the vehicle-mounted device 2, the information may indicate the course (traveling locus) in which the vehicle is predicted to travel in the future.

[Basic configuration of rider]
First, the basic configuration of the rider according to the embodiment will be described.

(1) Overall configuration FIG. 2 shows the overall configuration of the rider according to the embodiment. The rider 1 scans the surrounding space by appropriately controlling the emission direction (hereinafter, referred to as “scanning direction”) of the repeatedly emitted light pulse, and observes the return light to observe an object existing in the periphery. Get information about (eg distance and its existence probability or reflectance). Specifically, the rider 1 emits an optical pulse (hereinafter referred to as "emission light Lo") and is reflected by an external object (target) (hereinafter referred to as "return light Lr"). Generates information about an object by receiving light.

As shown in FIG. 2, the rider 1 is roughly classified into a system CPU 5, an ASIC 10, a transmitter 30, a receiver 40, and a scanning optical unit 50. The transmitter 30 repeatedly outputs a laser beam pulse having a width of about 5 nsec in response to the pulse trigger signal PT supplied from the ASIC 10. The optical pulse output from the transmitter 30 is guided to the scanning optical unit 50.

The scanning optical unit 50 emits an optical pulse output by the transmitter 30 in an appropriate direction, and collects the return light Lr returned by the emitted light encountering an object in space and being reflected or scattered. And lead to the receiver 40. The scanning optical unit 50 is an example of the “injection unit” in the present invention. The receiver 40 outputs a signal proportional to the intensity of the return light Lr to the ASIC 10. The receiver 40 is an example of the "light receiving unit" in the present invention.

By analyzing the output signal of the receiver 40, the ASIC 10 estimates and outputs parameters related to the object in the scanning space, for example, the distance thereof. Further, the ASIC 10 controls the scanning optical unit 50 so that appropriate scanning is performed. Further, the ASIC 10 supplies the transmitter 30 and the receiver 40 with the high voltage required by each.

At least, the system CPU 5 performs initial setting, monitoring, and control of the ASIC 10 through the communication interface. Other features vary depending on the application. In the case of the simplest rider, the system CPU 5 only converts the target information TI output by the ASIC 10 into an appropriate format and outputs it. For example, the system CPU 5 converts the target information TI into a highly versatile point cloud format and then outputs the target information TI through the USB interface.

(2) Transmitter The transmitter 30 outputs an optical pulse having a width of about 5 nsec in response to the pulse trigger signal PT supplied from the ASIC 10. The configuration of the transmitter 30 is shown in FIG. 3 (A). The transmitter 30 includes a charging resistor 31, a driver circuit 32, a capacitor 33, a charging diode 34, a laser diode (LD) 35, and a CMOS switch 36.

The pulse trigger signal PT input from the ASIC 10 drives a switch 36 such as CMOS via the driver circuit 32. The driver circuit 32 is inserted to drive the switch 36 at high speed. In-asserted period of the pulse trigger signal PT switch 36 is open, the capacitor 33 in the transmitter 30 is charged at a high voltage _{"V TX"} supplied from the ASIC 10. On the other hand, during the assert period of the pulse trigger signal PT, the switch 36 is closed and the electric charge charged in the capacitor 33 is discharged through the LD35. As a result, an optical pulse is output from the LD35.

(3) Receiver The receiver 40 outputs a voltage signal proportional to the intensity of the return light Lr from the object. Generally, a photodetector such as a PD or APD has a current output, so the receiver 40 converts this current into a voltage (I / V conversion) and outputs it. The configuration of the receiver 40 is shown in FIG. 3 (B). The receiver 40 includes an APD (Avalanche Photodiode) 41, an I / V converter 42, a resistor 45, a capacitor 46, and a low-pass filter (LPF) 47. The I / V conversion unit 42 includes a feedback resistor 43 and an operational amplifier 44.

In this embodiment, APD41 is used as the photodetector. The APD41, high voltage _{"V RX"} supplied are applied as a reverse bias from ASIC 10, flows detected current proportional to the return light Lr from the object. By applying a reverse bias close to the yield voltage of the APD41, a high avalanche gain can be obtained, and even a weak return light can be detected. The final stage LPF47 is installed for the purpose of limiting the bandwidth of the signal prior to sampling by the ADC 20 in the ASIC 10. In this embodiment, the sampling frequency of the ADC 20 is 512 MHz, and the cutoff frequency of the LPF 47 is about 250 MHz.

(4) Scanning Optical Unit The scanning optical unit 50 emits an optical pulse input from the transmitter 30 as an emission light Lo in an appropriate direction, and the emitted light Lo encounters an object in space and is reflected or scattered. As a result, the returned light Lr is guided to the receiver 40. A configuration example of the scanning optical unit 50 is shown in FIG. The scanning optical unit 50 includes a rotating mirror 61, a collimator lens 62, a condenser lens 64, an optical filter 65, a coaxial mirror 66, and a rotary encoder 67.

The optical pulse output from the LD35 of the transmitter 30 is incident on the collimator lens 62. The collimator lens 62 collimates the laser beam to an appropriate divergence angle (generally about 0 to 1 °). The emitted light from the collimator lens 62 is reflected vertically downward by the small coaxial mirror 66 and is incident on the rotation axis (center) of the rotation mirror 61. The rotating mirror 61 reflects the laser beam incident vertically above in the horizontal direction and emits it into the scanning space. The rotary mirror 61 is attached to the rotating portion of the motor 54, and the laser beam reflected by the rotary mirror 61 scans the horizontal plane as emission light Lo as the motor 54 rotates.

The return light Lr returned to the rider 1 by being reflected or scattered by an object existing in the scanning space is reflected vertically upward by the rotating mirror 61 and is incident on the optical filter 65. In addition to the return light Lr, the optical filter 65 also receives background light generated by illuminating the object with the sun or the like. The optical filter 65 is installed to selectively eliminate such background light. Specifically, the optical filter 65 selectively passes only components of about ± 10 nm before and after the wavelength of the emitted light Lo (905 nm in this embodiment). When the pass band of the optical filter 65 is wide, a large amount of background light enters the receiver 40 in the subsequent stage. As a result, a large DC current component appears at the output of the APD 41 in the receiver 40, and the SN deteriorates due to the influence of shot noise (background light shot noise) caused by this DC component, which is not preferable. However, if the pass band is excessively narrow, the emitted light itself will be suppressed, which is not preferable. The condenser lens 64 collects the light that has passed through the optical filter 65 and guides the light to the APD 41 of the receiver 40.

A rotary encoder 67 is attached to the motor 54 in order to detect the scanning direction. The rotary encoder 67 includes a turntable 68 attached to the motor rotating portion and a code detector 69 attached to the motor base. A slit indicating the rotation angle of the motor 54 is engraved on the outer circumference of the turntable 68, and the code detector 69 reads and outputs the slit. The specific specifications of the rotary encoder 67 and the motor control based on the output thereof will be described later.

In the above configuration, the collimator lens 62 constitutes the transmission optical system 51 shown in FIG. 2, the rotary mirror 61 and the motor 54 form the scanning unit 55 shown in FIG. 2, and the optical filter 65 and the condenser lens 64 constitute FIG. The receiving optical system 52 shown in FIG. 2 is configured, and the rotary encoder 67 constitutes the scanning direction detection unit 53 in FIG.

(5) ASIC
The ASIC 10 performs timing control of the emission light pulse, AD conversion of the APD output signal, and the like. Further, the ASIC 10 estimates parameters (distance, return light intensity, etc.) related to the object by performing appropriate signal processing on the AD conversion output, and outputs the estimation result to the outside. As shown in FIG. 2, the ASIC 10 includes a register unit 11, a clock generation unit 12, a synchronization control unit 13, a gate extraction unit 14, a reception segment memory 15, a DSP 16, and a high voltage generation unit (TXHV) for a transmitter. ) 17, a receiver high voltage generator (RXHV) 18, a preamplifier 19, an AD converter (ADC) 20, and a scanning control unit 21.

A register for communication with the system CPU 5, which is an external processor, is arranged in the register unit 11. The register provided in the register unit 11 is roughly classified into an R register that can be referred only from the outside and a W register that can be set from the outside. The R register mainly holds the status values inside the ASIC, and the system CPU 5 can monitor the internal status of the ASIC 10 by reading these values through the communication interface. On the other hand, the W register holds various parameter values referred to inside the ASIC 10. These various parameter values can be set from the system CPU 5 through the communication interface. The communication register may be realized by a flip-flop or as a RAM.

The clock generation unit 12 generates a system clock “SCK” and supplies it to each block in the ASIC 10. Many blocks of the ASIC 10 operate in synchronization with the system clock SCK. In this embodiment, the frequency of the system clock SCK is 512 MHz. The system clock SCK is generated by the PLL so as to be synchronized with the reference clock "RCK" input from the outside. Usually, a crystal oscillator is used as a source of the reference clock RCK.

TXHV17 produces a high voltage _{V TX} of the transmitter 30 requires. This high voltage is generated by boosting the low voltage with a DCDC converter circuit. As described below, TXHV17 varies the high voltage _{V TX} of generating on the basis of a control signal "Ct" supplied from the DSP 16, adjusting the voltage applied to the LD35 in the transmitter 30.

The RXHV18 generates the DC high voltage (about 100V) required by the receiver 40. This high voltage is generated by boosting a low voltage (about 5V to 15V) by a DCDC converter circuit.

The synchronization control unit 13 generates and outputs various control signals. The synchronous control unit 13 in this embodiment outputs two control signals, that is, a pulse trigger signal PT and an AD gate signal GT. An example of setting these control signals is shown in FIG. 5, and their temporal relationship is shown in FIG. As shown in FIG. 6, these control signals are generated in synchronization with a time interval (segment slot) divided at predetermined intervals. The time interval width (segment period) of the segment slot can be set by "nSeg". Here, the longer the segment period nSeg, the smaller the number of segment slots in the 360-degree scan of the emission light Lo, and the coarser the emission interval of the emission light Lo. On the other hand, the shorter the segment period nSeg, the larger the number of segment slots in the 360-degree scan of the emission light Lo, and the denser the emission intervals of the emission light Lo.

The pulse trigger signal PT is supplied to the transmitter 30 provided outside the ASIC 10. The transmitter 30 outputs an optical pulse in response to the pulse trigger signal PT. For the pulse trigger signal PT, the delay "dTrg" and the pulse width "wTrg" with respect to the segment slot start point can be set. The pulse width wTrg is determined in consideration of the trigger response specifications of the transmitter 30 because the transmitter 30 does not react if it is too narrow.

The AD gate signal GT is supplied to the gate extraction unit 14. As will be described later, the gate extraction unit 14 extracts only the assert section of the AD gate signal GT from the ADC output signals input from the ADC 20 and stores it in the reception segment memory 15. For the AD gate signal GT, the delay time “dGate” and the gate width “wGate” for the segment slot start point can be set. Here, the longer the gate width wGate, the longer the maximum distance measurement distance (distance measurement limit distance) of the rider 1.

Further, in this embodiment, the synchronization control unit 13 changes the segment period nSeg based on the control signal “Cs” supplied from the DSP 16. Specifically, the synchronous control unit 13 sets the segment period nSeg to be shorter than the normal period (for example, nSeg = 8192) in the scanning direction in which the emission light Lo is densely emitted based on the control signal Cs, and the emission light. In the scanning direction in which Lo is roughly ejected, the segment period nSeg is set longer than the normal period. Further, in addition to this, the synchronous control unit 13 sets the gate width wGate longer than the normal width (for example, wGate = 1024) in the scanning direction in which the emission power of the emission light Lo is increased, so that the maximum distance measurement of the rider 1 can be performed. In the scanning direction in which the distance is lengthened and the emission power of the emission light Lo is weakened, the maximum distance measurement distance of the rider 1 may be shortened by setting the gate width wGate shorter than the normal width.

The preamplifier 19 amplifies the analog voltage signal input from the receiver 40 installed outside the ASIC 10 and supplies it to the subsequent ADC 20. The voltage gain of the preamplifier 19 can be set by the W register.

The ADC 20 AD-converts the output signal of the preamplifier 19 and converts it into a digital series. In this embodiment, the system clock SCK is used as the sampling clock of the ADC 20, and the input signal of the ADC 20 is sampled at 512 MHz.

The gate extraction unit 14 extracts only the assert section of the AD gate signal GT from the ADC output signals input from the ADC 20 and stores it in the reception segment memory 15. The section signal extracted by the gate extraction unit 14 is hereinafter referred to as “received segment signal RS”. That is, the reception segment signal RS is a real number vector whose vector length is equal to the gate width wGate.

Here, the relationship between the ADC output signal and the reception segment and the setting of the gate position will be described. FIG. 7A shows a segment slot. As shown in FIG. 7B, the pulse trigger signal PT is asserted with a delay of dTrg with respect to the segment slot start point. In the example of FIG. 7, since “dtrg = 0”, the pulse trigger signal PT is asserted at the segment slot start point. FIG. 7C shows an ADC output signal (received segment signal RS) when an object is placed at the scanning origin of the rider. That is, FIG. 7C illustrates the reception segment signal RS when the target distance (radius R) is 0 m. As shown, even when the R = 0 m, the rise of the received pulse is observed later than the rise of the pulse trigger signal by the system delay D _SYS. The causes of the system delay _DSYS include the electrical delay of the LD driver circuit in the transmitter 30, the optical delay in the transmission optical system 51, the optical delay in the reception optical system 52, and the electrical delay in the receiver 40. Delay, conversion delay at ADC20, etc. can be considered.

FIG. 7D exemplifies the reception segment signal RS when the object is placed in the radius R. In this case, as compared with FIG. 7C, the delay is increased by the round-trip time of the light from the scanning origin to the object. This increased delay is the so-called "TOF (Time Of Flight) delay". If this TOF delay is used as the D sample, the radius R can be calculated by the following formula.

図７（Ｆ）は、「ｄＧａｔｅ＝０」の場合のＡＤゲート信号ＧＴを例示するものである。前述したとおり、ゲート抽出部１４は、ＡＤＣ出力信号から、ＡＤゲート信号ＧＴのアサート区間のみを抽出する。後述するＤＳＰ１６は、この抽出区間のみに基づいて、物体に関するパラメータ推定を行う。したがって、ＴＯＦ遅延時間が大きい場合には、物体からの戻りパルス成分がゲートからはみ出してしまい正当なパラメータ推定が行えない。正当なパラメータ推定が行われるためにはＴＯＦ遅延時間Ｄが次式を満たしていることが必要となる。

FIG. 7F exemplifies the AD gate signal GT in the case of “dGate = 0”. As described above, the gate extraction unit 14 extracts only the assert section of the AD gate signal GT from the ADC output signal. DSP16, which will be described later, estimates parameters related to the object based only on this extraction interval. Therefore, when the TOF delay time is large, the return pulse component from the object protrudes from the gate, and proper parameter estimation cannot be performed. In order for proper parameter estimation to be performed, it is necessary that the TOF delay time D satisfies the following equation.

ここでＬ_ＩＲはシステムの総合インパルス応答の長さであり、Ｄ_ＭＡＸは正当なパラメータ推定が可能な最大ＴＯＦ遅延時間として定義される。図７（Ｅ）は、ＴＯＦ遅延時間がこの最大ＴＯＦ遅延時間に等しい場合の受信セグメント信号ＲＳを例示している。

Here, _LIR is the length of the total impulse response of the system, and _DMAX is defined as the maximum TOF delay time at which a valid parameter can be estimated. FIG. 7E illustrates the received segment signal RS when the TOF delay time is equal to this maximum TOF delay time.

Instead of the example of FIG. 7, the gate delay dGate may be set to be equal to the system delay time. By setting in this way, it is possible to estimate the parameters properly even for an object at a longer distance.

The scanning control unit 21 monitors the output of the rotary encoder 67 installed outside the ASIC 10, and controls the rotation of the motor 54 based on the output. Specifically, the scanning control unit 21 sends the torque control signal "TC" to the motor 54 based on the scanning direction information "SDI" output from the rotary encoder 67 (scanning direction detection unit 53) of the scanning optical unit 50. Supply. The rotary encoder 67 in this embodiment outputs two pulse trains (hereinafter, referred to as “encoder pulse”) of A phase and Z phase. The time relationship between the two pulse trains is shown in FIG. 8 (A). As shown in the figure, for the A phase, one pulse is generated and output for every 1 ° of rotation of the motor 54. Therefore, 360 A-phase encoder pulses are generated and output for each rotation of the motor 54. On the other hand, for the Z phase, one pulse is generated and output for each rotation of the motor 54 corresponding to a predetermined rotation angle.

The scanning control unit 21 measures the rising time of the encoder pulse as a counter value of the system clock SCK, and controls the torque of the motor 54 so that this becomes a desired value. That is, the scanning control unit 21 PLL-controls the motor 54 so that the encoder pulse and the segment slot have a desired time relationship.

The time relationship between the encoder pulse and the segment slot can be set by the W register shown in FIG. 8 (B). The number of A-phase encoder pulses for each motor rotation is set in "nPpr". This is a value determined by the specifications of the rotary encoder 67, and in this embodiment, the above-mentioned 360 is set. “NRpf” gives the number of rotations per frame, and “nSpf” gives the number of segments per frame. Further, "dSmpA" and "dSmpZ" are prepared to adjust the time relationship between the rising edge of the encoder pulse and the segment slot in sample clock units, and can specify the delay of the encoder pulse with respect to the segment slot start point. .. On the other hand, "dSegZ" is prepared for adjusting the time relationship between the rise of the Z-phase pulse and the frame on a segment-by-segment basis.

FIG. 9 shows the time relationship between the encoder pulse and the segment slot in the steady state. As shown in the figure, in the default setting, one frame is composed of 1800 segments, and the motor 54 makes one rotation in one frame.

(6) DSP
First, a process in which the DSP 16 _{reads the reception segment “y frm, seg} ” from the reception segment memory 15 and executes it will be described. Here, "frm" is a frame index and "seg" is a segment index. Hereinafter, the notation of these indexes will be omitted to the extent that there is no risk of misunderstanding.

FIG. 10A shows a block diagram of signal processing performed by DSP16. As shown, the DSP 16 includes a reception filter 71, a peak detector 72, a determination unit 73, and a formatter 74. The DSP 16 sequentially reads the reception segment y from the reception segment memory 15 and performs processing on the reception segment y. The reception segment y is a real number vector having a vector length of wGate, and is expressed by the following equation.

受信フィルタ７１は、受信セグメントｙに対して、所定のインパルス応答を畳み込んで、フィルタードセグメントｚを算出する。ピーク検出部７２は、フィルタードセグメントｚ内で振幅が最大となる点、即ちピーク点を検出し、当該ピーク点の遅延Ｄと振幅Ａを出力する。判定部７３は、振幅Ａが所定の閾値ｔＤｅｔより大きい点のみを選択的にフォーマッタ７４に送る。フォーマッタ７４は、遅延Ｄと振幅Ａ、及び当該セグメントのフレームインデックスｆｒｍ、セグメントインデックスｓｅｇを、適切なフォーマットに変換して外部に出力する。以下、各ブロックについて詳しく説明する。

The reception filter 71 convolves a predetermined impulse response with respect to the reception segment y to calculate the filtered segment z. The peak detection unit 72 detects the point where the amplitude becomes maximum in the filtered segment z, that is, the peak point, and outputs the delay D and the amplitude A of the peak point. The determination unit 73 selectively sends only the points whose amplitude A is larger than the predetermined threshold value tDet to the formatter 74. The formatter 74 converts the delay D and the amplitude A, the frame index frm of the segment, and the segment index seg into an appropriate format and outputs the format to the outside. Hereinafter, each block will be described in detail.

The reception filter unit 71 convolves a predetermined impulse response h with respect to the reception segment y (circular convolution) to calculate the filtered segment z. The impulse response of the reception filter unit 71 can be set by the W register, and is set in advance by the system CPU 5 so that the SNR at the filter output becomes large.

For example, the filter impulse response h is set to satisfy the following equation. By setting in this way, optimal performance (high SNR) can be realized when the noise is white and the total system impulse response is significantly shorter than that of wGate.

上式において、リファレンスパルスｇは走査原点（Ｒ＝０ｍ）に物体を置いた場合に観測される受信セグメント波形であり、トランスミッタ３０とレシーバ４０を含むシステム全体の総合インパルス応答を代表している。実際に走査原点に物体を置くことが困難な場合には、例えば「Ｒ＝１ｍ」での受信セグメント波形を観測し、これを数学的に時間シフトすることで、等価的にリファレンスパルスを測定すれば良い。

In the above equation, the reference pulse g is a reception segment waveform observed when an object is placed at the scanning origin (R = 0 m), and represents the total impulse response of the entire system including the transmitter 30 and the receiver 40. When it is difficult to actually place the object at the scanning origin, for example, observe the received segment waveform at "R = 1 m" and mathematically shift the time to measure the reference pulse equivalently. Just do it.

The peak detection unit 72 detects the point where the amplitude is maximum in the filtered segment, that is, the peak point with subsample accuracy, and outputs the delay D and the amplitude A of the peak point. The determination unit 73 determines whether or not an object exists at the detection point based on the peak point information D and A (delay D, amplitude A) output from the peak detection unit 72. This determination is made by comparing the amplitude A of the peak point with the determination threshold tDec. Specifically, the determination unit 73 determines that "an object exists" when A> tDec, and outputs the peak point information. On the other hand, when A ≦ tDec, the determination unit 73 determines that “the object does not exist” and does not output the peak point information. The formatter 74 converts the peak point information D and A output from the determination unit 73 and the scanning information (frame index frm, segment index seg) corresponding to the peak point into a format that is easy for the user (upper system) to use.

The circular convolution operation of the reception filter 71 may be realized in the frequency domain by using the DFT. By doing so, the amount of calculation can be significantly reduced. In this case, instead of making the impulse response h settable by the W register, it is preferable that the impulse response h is DFT calculated in advance to obtain the frequency response H so that the frequency response H can be set. FIG. 10B shows a block diagram of signal processing performed by DSP 16 when the circular convolution operation of the reception filter 71 is realized in the frequency domain using DFT.

Further, the DSP 16 performs control (also referred to simply as “injection control”) for adjusting the emission power and the emission interval (that is, the scanning angle resolution) of the emission light Lo according to the scanning direction of the emission light Lo. In this case, the DSP 16 performs injection control using the control signals Ct and Cs.

Specifically, first, the DSP 16 detects the scanning direction based on the scanning direction information SDI received from the scanning direction detection unit 53. Then, DSP 16, in response to the detected scanning direction, by supplying the control signal Ct for adjusting the high voltage _{V TX} generated by TXHV17 in TXHV17, adjust the emission power of the LD 35. Further, the DSP 16 adjusts the injection interval by supplying the control signal Cs for adjusting the segment period nSeg to the synchronization control unit 13 according to the detected scanning direction. In this case, for example, DSP 16 is a table or the like indicating a combination of the high voltage V _TX and segments periods nSeg be set for each scanning direction is stored in advance in the W register or the like, by referring to the table was detected Control signals Ct and Cs are generated according to the scanning direction. The specific setting of the emission power and the emission interval of the emission light Lo for each scanning direction will be described in the next section. The DSP 16 is an example of a "first acquisition unit", a "second acquisition unit", a "control unit" in the present invention, and a computer that executes a program in the present invention.

[Setting of injection power and injection interval according to scanning direction]
Next, an example of setting the injection power and the injection interval according to the scanning direction will be described. The DS16 executes a control mode (also referred to as a "normal mode") in which light is uniformly (with the same intensity and frequency) emitted in all directions during normal traveling of the vehicle. In this embodiment, the DSP 16 may be changed to the normal mode to carry out the following first to fourth control modes. An example of setting the injection power and the injection interval will be described below.

(1) Setting in the First Control Mode FIG. 11 is a plan view of the periphery of the vehicle in which the emission power and the emission interval of the emission light Lo in the 360-degree scan in the first control mode are schematically shown by broken line arrows. .. In FIG. 11, the length of the broken line arrow indicates the injection power, and the interval of the broken line arrow indicates the emission interval (injection frequency) of the emission light Lo. The length of the broken line arrow shown in FIG. 11 does not indicate the range actually reached by the emitted light Lo, and the number of broken line arrows is the number of the emitted light Lo actually emitted in the 360-degree scan. Does not match the number.

As shown in FIG. 11, in the first control mode, the DSP 16 makes the emission power of the emission light Lo higher than usual in the front direction of the vehicle (in FIG. 11, the direction within a range of about 30 degrees to the left and right with respect to the traveling direction). It is strong and the interval between the emitted light Lo is coarse (that is, the scanning angle resolution is low). In this way, the DSP 16 makes the emission power of the emission light Lo emitted in the front direction of the vehicle stronger than usual from the viewpoint of detecting an obstacle farther away. Further, in this case, the DSP 16 roughly emits the emission light Lo emitted in the front direction of the vehicle from the viewpoint of eye safety and the like. As a result, the DSP 16 can preferably satisfy the eye-safe standard while preferentially detecting a relatively large object located in front of the vehicle in a distance range equal to or greater than the braking distance. In other words, it is possible to detect an object in front of the vehicle that is farther than the side or the rear while suitably satisfying the eye-safe standard.

Further, as shown in FIG. 11, in the first control mode, the DSP 16 makes the emission power of the emission light Lo weaker than usual in the rear direction of the vehicle (in FIG. 11, the direction corresponding to about 30 degrees to the left and right with respect to the reverse direction). And, the emission light Lo is roughly emitted. In this way, the DSP 16 prevents unnecessary detection of distant objects existing behind the vehicle in the rear direction where the need for obstacle detection is relatively low.

Further, as shown in FIG. 11, in the first control mode, the DSP 16 makes the emission power of the emission light Lo weaker than usual in the side direction (right side direction, left side direction) of the vehicle, and the emission light Lo Increase the spacing (ie, increase scanning angle resolution). In general, objects that are far away in the lateral direction are far from the road and need less to be detected. On the other hand, when it is necessary to detect kilometer posts, other signs, signboards, etc. that are relatively close in the side direction as landmarks in self-position estimation, for example, and they have a relatively thin shape. There is. Further, it is highly necessary to detect a moving body existing in the lateral direction (for example, a vehicle in another lane or a pedestrian on a sidewalk) from the viewpoint of obstacle detection. In addition, if the frequency of injection is simply increased, it may not be possible to meet the eye-safe standard. In consideration of the above, the DSP 16 makes the emission power of the emission light Lo weaker than usual in the side direction of the vehicle, and by emitting the emission light Lo densely, the DSP 16 preferably satisfies the eye safety standard and is relatively close to the vehicle. Detects existing objects in the side direction of the vehicle with high accuracy.

(2) Setting in the 2nd to 4th Control Modes Next, an example of setting the injection power and the injection interval for each scanning direction when a predetermined condition is satisfied will be described. Hereinafter, three modes (second to fourth control modes) will be described in order as specific examples.

(2-1) When traveling on a road adjacent to the sidewalk DSP16 is a road adjacent to the sidewalk based on the current position information IP and map information IM (in the case of a road having multiple lanes, the lane closest to the sidewalk). When it is detected that the vehicle is traveling, the emission power and scanning angle resolution of the emission light Lo are controlled by the second control mode described below. In this case, for example, the DSP 16 recognizes the currently traveling road based on the current position information IP and the map information IM, and determines whether or not there is a sidewalk adjacent to the road with reference to the map information IM.

FIG. 12 is a plan view of the periphery of the vehicle in which the emission power and the emission interval of the emission light Lo in the 360-degree scan in the second control mode are roughly shown by the broken line arrows. In the example of FIG. 12, the DSP 16 recognizes that the vehicle is traveling in the lane 81 adjacent to the sidewalk 80 registered in the map information IM based on the current position information IP and the map information IM, and executes the second control mode. ..

In the example of FIG. 12, the DSP 16 makes the emission power of the emission light Lo slightly stronger in the left side direction, which is the side direction in which the sidewalk 80 exists, than in the right side direction, and makes the emission light Lo dense (that is,). Eject (high scanning angle resolution). In other words, the DSP 16 densely emits the emission light Lo in the direction of the left side surface, and strengthens the emission power of the emission light Lo within a range satisfying the eye safe standard.

As described above, in the second control mode, the DSP 16 makes the emission power of the emission light Lo in the direction of the left side surface where the sidewalk 80 exists stronger than the emission power of the emission light Lo in the direction of the right side surface on the opposite side. Moreover, the scanning angle resolution of the emitted light Lo in the left side surface direction is made higher than the scanning angle resolution of the emitted light Lo in the opposite right side surface direction. By doing so, the DSP 16 can suitably improve the object detection accuracy on the sidewalk where there are pedestrians and the like who need to be accurately captured for safety.

Further, in the second control mode, the DSP 16 makes the emission power of the emission light Lo stronger than usual and makes the interval of the emission light Lo coarser (that is, scans) in the front direction of the vehicle, as in the first control mode described above. The angular resolution may be lowered). As a result, the DSP 16 preferentially detects a relatively large obstacle located in front of the vehicle in a distance range equal to or greater than the braking distance while satisfying the eye-safe standard as in the first control mode. Further, in the second control mode, the DSP 16 makes the emission power of the emission light Lo weaker than usual and emits light in the rear direction of the vehicle in which the need for obstacle detection is relatively low, as in the first control mode. The Lo interval may be coarse.

(2-2) When turning right at an intersection When DSP16 detects that the vehicle has approached the intersection where it should turn right within a predetermined distance based on the current position information IP, map information IM, and route information IR, it will be explained below. Injection control is performed in the third control mode. In this case, for example, the DSP 16 recognizes the currently traveling road based on the current position information IP and the map information IM, and determines the presence or absence of a right turn point on the recognized road based on the route information IR. Then, when the DSP 16 determines that the right turn point exists, it determines whether or not the distance from the current position to the right turn point is within a predetermined distance, and when the distance is within a predetermined distance, the third control mode is set. Execute.

FIG. 13 is a plan view of the periphery of the vehicle in which the emission power and the emission interval of the emission light Lo in the 360-degree scan in the third control mode are roughly shown by the broken line arrows. In the example of FIG. 13, the DSP 16 recognizes that it has approached the intersection 82 corresponding to the next right turn point within a predetermined distance based on the current position information IP, the map information IM, and the route information IR, and sets the third control mode. Execute.

In the example of FIG. 13, the DSP 16 makes the emission power of the emission light Lo more than usual in the right front direction (in FIG. 13, the direction within about 45 degrees to the right from the straight direction), which is the direction in which the oncoming vehicle is estimated to exist. Is also strong. Further, in consideration of satisfying the eye-safe standard, the emitted light Lo is roughly emitted (that is, the scanning angle resolution is low). In this way, in the third control mode, when the oncoming vehicle is to be detected preferentially when turning right, the injection power is increased more than usual so that the oncoming vehicle that exists some distance can be detected in consideration of the case where the oncoming vehicle moves at high speed. Also strengthen. As a result, the DSP 16 can suitably detect an oncoming vehicle while suitably complying with the eye safety standard.

In the example of FIG. 13, the DSP 16 sets the emission power and scanning angle resolution of the emission light Lo to a normal setting or a setting lower than usual in a direction other than the right front direction, which is a direction in which an oncoming vehicle is presumed to exist. I have to.

(2-3) When turning left at an intersection When DSP16 detects that a vehicle has approached an intersection where it should turn left within a predetermined distance based on the current position information IP, map information IM, and route information IR, it will be explained below. The emission power and scanning angle resolution of the emission light Lo are controlled by the fourth control mode. In this case, for example, the DSP 16 recognizes the currently traveling road based on the current position information IP and the map information IM, and determines the presence or absence of a left turn point on the recognized road based on the route information IR. Then, when the DSP 16 determines that the left turn point exists, it determines whether or not the distance from the current position to the left turn point is within a predetermined distance, and when the distance is within a predetermined distance, the fourth control mode is set. Execute.

FIG. 14 is a plan view of the periphery of the vehicle in which the emission power and the scanning angle resolution of the emission light Lo in the 360-degree scanning in the fourth control mode are roughly shown by the broken line arrows. In the example of FIG. 14, the DSP 16 recognizes that it has approached the intersection 83 corresponding to the next left turn point within a predetermined distance based on the current position information IP, the map information IM, and the route information IR, and sets the fourth control mode. Execute.

In the example of FIG. 14, the DSP 16 is in the left side direction (centered in the left direction of the vehicle in FIG. 14), which is the direction in which it is estimated that there are pedestrians crossing the pedestrian crossing going straight through the intersection 83, motorcycles going straight through the intersection 83, and the like. The emission power is weak and the emission light Lo is densely emitted.

In general, when turning left, it is necessary to preferentially detect a relatively close object existing in the direction of the left side surface of the vehicle, particularly in order to prevent pedestrians and two-wheeled vehicles from being involved while crossing. In consideration of the above, in the fourth control mode, the scanning angle resolution is increased so that pedestrians and motorcycles crossing can be reliably detected while the injection power is weaker than usual in the left side direction. As a result, the DSP 16 can accurately detect pedestrians, motorcycles, etc. that should be noted while suitably satisfying the eye-safe standard when turning left.

Further, in the example of FIG. 14, the DSP 16 sets the emission power and the scanning angle resolution of the emission light Lo to a normal setting or a setting lower than the normal setting in a direction other than the left side surface direction.

As described above, the rider 1 according to the embodiment includes a scanning unit 55 that irradiates the emission light Lo in response to the pulse trigger signal PT, an APD 41 that receives the return light Lr of the emission light Lo, and a DSP 16. The DSP 16 acquires the current position information IP or the like indicating the position of the vehicle from the vehicle-mounted device 2. Then, the DSP 16 controls the intensity and the emission frequency of the emission light Lo emitted by the scanning unit 55 based on the current position information IP and the like. As a result, the rider 1 can suitably improve the performance of object detection required for automatic driving and the like.

[Modification example]
Next, a modification suitable for the embodiment will be described. The following modifications may be combined and applied to the above-described embodiment.

(Modification example 1)
The DSP 16 determines the necessity of executing the third or fourth control mode by receiving the blinker information from the vehicle by a predetermined communication protocol such as CAN instead of receiving the route information IR or the like from the vehicle-mounted device 2. You may.

In this case, the DSP 16 should determine that the third control mode should be executed when it receives the blinker information indicating that it turns right, and should execute the fourth control mode when it receives the blinker information indicating that it turns left. Judge. Also in this aspect, the rider 1 can preferably detect that the vehicle is approaching the right turn point or the left turn point, and execute the injection control suitable for the situation. In this case, the blinker information is an example of "route information" in the present invention.

(Modification 2)
As the emission control, the DSP 16 may control only one of the emission power and the emission interval of the emission light Lo.

For example, when adjusting only the emission power of the emission light Lo, the DSP 16 makes the injection power in the forward direction stronger than the injection power in the other directions in the first control mode, and in the third control mode, it is in the right front direction. Make the injection power stronger than the injection power in other directions. Further, when adjusting only the emission interval of the emission light Lo, the DSP 16 emits the emission light Lo more densely in the side surface direction than in the other directions in the first control mode, and on the left side in the second and fourth control modes. The emission light Lo is emitted more densely in the surface direction than in other directions. As described above, even in this modification, the DSP 16 can suitably improve the detection accuracy of the target to be detected with priority.

1 Rider 2 On-board unit 10 ASIC
16 DSP
17 High voltage generator for transmitter (TXHV)
18 High voltage generator for receiver (RXHV)
30 transmitter 35 LD
40 Receiver 50 Scanning optics

Claims (10)

A detection device that can be placed on a moving object
The injection part that emits light and
A light receiving unit that receives the light reflected by the object,
A control unit that controls at least one of the intensity of light emitted by the injection unit and the frequency of emission is provided.
The control unit is used when the moving body is traveling in the lane adjacent to the sidewalk.
Intensity of the light to which the walkway is emitted to the side of the present side is controlled to be higher than the intensity of light emitted to the side opposite,
Or
Frequency of the light to the side of the side where the trail there is emitted is, the light is controlled to be higher than the frequency emitted to the side of the opposite side, the detection device. It further has a first acquisition unit that acquires position information indicating the position of the moving body.
The detection device according to claim 1, wherein the control unit controls at least one of the intensity of light emitted by the injection unit and the frequency of emission based on the position information. A second acquisition unit for acquiring route information regarding the movement route of the moving body is further provided.
The detection device according to claim 2, wherein the control unit controls at least one of the intensity of light emitted by the injection unit and the frequency of emission based on the position information and the path information. The detection device according to any one of claims 1 to 3, wherein the control unit controls the injection unit so that the intensity of light and the frequency of emission differ between the front side and the side of the moving body. .. The detection device according to claim 4, wherein the control unit controls the front of the moving body so that the light intensity is high and the emission frequency is low with respect to the side of the moving body. When the moving body makes a right turn, the control unit controls the front right side of the moving body so that the intensity of the light is higher and the frequency at which the light is emitted is lower than that of the other. , The detection device according to claim 3. The control unit controls the left side of the moving body so that when the moving body makes a left turn, the intensity of the light is weaker and the light is emitted more frequently with respect to the other side. The detection device according to 3 or 6. It is a control method executed by a detection device that has an injection unit that emits light and a light receiving unit that receives the light reflected by an object and can be arranged on a moving body.
It has a control step of controlling at least one of the intensity of light emitted by the injection unit and the frequency of injection.
The control step is when the moving body is traveling in the lane adjacent to the sidewalk.
Intensity of the light to which the walkway is emitted to the side of the present side is controlled to be higher than the intensity of light emitted to the side opposite,
Or
The method frequently the light to the side of the side is injected is controlled so that the light to the side of the opposite side is higher than the frequency emitted to the sidewalk is present. A program executed by a computer of a detection device that has an emitting unit that emits light and a light receiving unit that receives the light reflected by an object and can be arranged on a moving body.
The computer is made to function as a control unit that controls at least one of the intensity of light emitted by the injection unit and the frequency of emission.
The control unit is used when the moving body is traveling in the lane adjacent to the sidewalk.
Intensity of the light to which the walkway is emitted to the side of the present side is controlled to be higher than the intensity of light emitted to the side opposite,
Or
Frequency of the light to the side of the side where the trail there is emitted is, a program for controlling such that the light on the side of the opposite side is higher than the frequency emitted. A storage medium that stores the program according to claim 9.

Images