WO2020170700A1

WO2020170700A1 - Vehicle vicinity monitoring system

Info

Publication number: WO2020170700A1
Application number: PCT/JP2020/002130
Authority: WO
Inventors: 利明長井; 木村　禎祐; 水野　文明; 晶文植野
Original assignee: 株式会社デンソー
Priority date: 2019-02-20
Filing date: 2020-01-22
Publication date: 2020-08-27

Abstract

A first optical distance measurement device 20 in a vehicle vicinity monitoring system 200 comprises: a light emission unit 40 for emitting emission light; a light reception unit 60 for receiving emission light that has been projected toward a measurement range 80 and reflected from the measurement range and outputting a signal corresponding to the light reception state of the reflected light; and a measurement unit 100 for using the signal output from the light reception unit to measure the distance to an object included in the measurement range. The shape of the measurement range when the emission light is projected horizontally onto a vertical cylindrical surface surrounding the first optical distance measurement device may be a narrow-edged shape in which the vertical width of at least one horizontal end of the measurement range is smaller than the vertical width of the horizontal center of the measurement range.

Description

Vehicle surroundings monitoring system

Cross-reference of related applications

This application is based on Japanese application No. 2019-028027 filed on February 20, 2019 and Japanese application No. 2020-004060 filed on January 15, 2020, the description of which is hereby incorporated. Incorporate.

The present disclosure relates to a vehicle surroundings monitoring system.

An optical range finder is known that measures the distance to an object by irradiating the object with light and measuring the reflected light. For example, Japanese Unexamined Patent Application Publication No. 2017-125790 discloses a vehicle surroundings monitoring system that measures a distance from an object around the entire vehicle by an optical distance measuring device mounted on the vehicle.

In such a vehicle periphery monitoring system, the range of irradiation light is generally rectangular because the entire circumference of the vehicle is measured by the optical distance measuring device. If the irradiation direction of the irradiation light has a predetermined depression angle with respect to the horizontal direction, the range of the irradiation light expands due to the increase in the distance to the road surface at the horizontal end of the measurement range, so that the vicinity of the vehicle can be efficiently There was a problem that it could not be measured. Further, when such an optical distance measuring device is used in combination with a device oriented in the horizontal direction and a device oriented in the depression angle side, there is a problem that the measurement range overlaps in the vehicle periphery monitoring system and the efficiency deteriorates. was there.

The present disclosure has been made to solve at least a part of the above problems, and can be realized as the following modes or application examples.

According to an aspect of the present disclosure, vehicle

periphery monitoring systems

200, 200b, 200c are provided. This vehicle periphery monitoring system is an optical

distance measuring device

20, 20b, 20c, and is directed toward

light emitting units

40, 40b, 40c that emit irradiation light and

predetermined measurement ranges

80, 80b, 80c, 80d. By using the light receiving unit 60 that receives the reflected light from the measurement range of the projected irradiation light and outputs a signal according to the light receiving state of the reflected light, and the signal output from the light receiving unit, A first optical distance measuring device comprising: a measuring unit 100 that measures a distance to an object included in a measurement range, wherein the irradiation light is a cylinder along the vertical direction that surrounds the first optical distance measuring device. The shape of the measurement range when projected along the horizontal direction on a flat plane is such that the width in the vertical direction at the at least one end of the measurement range in the horizontal direction is the width in the vertical direction at the center in the horizontal direction. The narrower end narrower than the first optical

distance measuring device

20, 20b, 20c, and the second irradiation light projected toward the predetermined second measurement range 82 from the second measurement range. Received as the second reflected light, using a signal according to the light receiving state of the second reflected light, a second optical distance measuring device for measuring the distance to the object included in the second measurement range, The second measurement when the second irradiation light projected toward the second measurement range is projected in the horizontal direction on a cylindrical plane along the vertical direction that surrounds the second optical distance measuring device. The shape of the range includes a second optical distance measuring device 22 in which the width in the vertical direction at the horizontal center of the second measurement range is the same as the width in the vertical direction at both ends in the horizontal direction. In the first optical distance measuring device and the second optical distance measuring device, the depression angle of the irradiation direction LD1 of the irradiation light by the first optical distance measuring device is equal to that of the second irradiation light by the second optical distance measuring device. The vehicle 70 may be arranged so that the depression angle is larger than the irradiation direction LD2.

According to the vehicle periphery monitoring system of this aspect, in the measurement range of the irradiation light by the first optical distance measuring device, the width in the vertical direction at both end sides in the horizontal direction is larger than the width in the vertical direction at the center in the horizontal direction. It has a narrow narrow end. As a result, it is possible to efficiently detect the object in the vicinity of the first optical distance measuring device. It is possible to reduce the overlapping portion between the first measurement range of the first optical distance measuring device and the second measurement range of the second optical distance measuring device, and it is possible to efficiently detect an object near the vehicle.

The present disclosure can be implemented in various forms other than the vehicle periphery monitoring system. For example, a vehicle surroundings monitoring method, an optical ranging method, a vehicle equipped with a vehicle surroundings monitoring system, a vehicle equipped with an optical ranging device, a control method for controlling the vehicle surroundings monitoring system, a control method for controlling the optical ranging device, etc. Can be realized in the form of.

The above and other objects, features and advantages of the present disclosure will become more apparent by the following detailed description with reference to the accompanying drawings. The drawing is
FIG. 1 is a schematic configuration diagram of the optical distance measuring device according to the first embodiment, FIG. 2 is a schematic configuration diagram showing an optical system, FIG. 3 is an explanatory diagram schematically showing the configuration of the light receiving array, FIG. 4 is a schematic configuration diagram of the SPAD operation unit, FIG. 5 is an explanatory diagram showing operations in the vertical and horizontal directions of the irradiation direction of the mirror, FIG. 6 is an explanatory view showing a combined operation of the irradiation directions of the mirrors, FIG. 7 is an explanatory diagram showing a measurement range of the optical distance measuring device according to the first embodiment, FIG. 8 is an explanatory diagram showing a vertical measurement range of the vehicle periphery monitoring system of the first embodiment, FIG. 9 is an explanatory view showing the measurement range of the second optical distance measuring device, FIG. 10 is an explanatory diagram showing a horizontal measurement range of the vehicle periphery monitoring system, FIG. 11 is a schematic configuration diagram of the first optical distance measuring device in the second embodiment, FIG. 12 is a schematic configuration diagram showing the configuration of the light emitting element array, FIG. 13 is an explanatory diagram showing control of the mirror and the light emitting element array, FIG. 14 is an explanatory diagram showing the measurement range of the first optical distance measuring device in the second embodiment, FIG. 15 is a schematic configuration diagram of the first optical distance measuring device according to the third embodiment, FIG. 16 is an explanatory diagram showing the measurement range of the first optical distance measuring device in the fourth embodiment.

A. First embodiment:
FIG. 1 shows an optical distance measuring device 20 included in the vehicle periphery monitoring system 200 of the first embodiment as a first optical distance measuring device. The optical distance measuring device 20 is a device that optically measures a distance. As shown in FIG. 1, the optical distance measuring device 20 includes an optical system 30 that emits irradiation light for distance measurement to a predetermined measurement range 80 and receives reflected light from an object, and an optical system. And a SPAD calculation unit 100 for processing the signal obtained from The optical system 30 includes a light emitting unit 40 that emits laser light as irradiation light, a projection unit 50 that projects irradiation light toward the measurement range 80, and a light receiving unit 60 that receives reflected light from the measurement range 80. Prepare

The details of the optical system 30 are shown in FIG. In the present embodiment, the light emitting unit 40 includes a semiconductor laser element (hereinafter, also simply referred to as a laser element) 41 that emits a laser beam for distance measurement, a circuit board 43 in which a drive circuit for the laser element 41 is incorporated, and a laser element. And a collimator lens 45 for collimating the laser beam emitted from the laser beam 41. The laser element 41 is a laser diode capable of oscillating a so-called short pulse laser, and in the present embodiment, has a laser emission region having a vertically long shape along the vertical direction. The pulse width of the laser light of the laser element 41 is about 5 nsec. The resolution of distance measurement is improved by using a short pulse of 5 nsec.

The projection unit 50 is configured by a so-called two-dimensional scanner that scans the irradiation light in the vertical direction and the horizontal direction in the present embodiment. The projection unit 50 includes a mirror 53 that is a reflecting unit that reflects the laser light that is collimated by the collimator lens 45, a rotating frame 52 that supports the mirror 53, a support frame 51 that supports the rotating frame 52, and a first frame. A first rotary solenoid 55 that rotationally drives the rotary shaft AX1 and a second rotary solenoid 57 that rotationally drives the second rotary shaft AX2 are provided. Hereinafter, the first rotary solenoid 55 is also simply referred to as the first solenoid 55, and the second rotary solenoid 57 is also simply referred to as the second solenoid 57. The first rotation axis AX1 is a rotation axis having a V direction parallel to the vertical direction as an axis direction, and the second rotation axis AX2 is a rotation axis having an H direction parallel to the horizontal direction as an axis direction.

The first solenoid 55 receives a control signal Sm1 from the outside and repeats normal rotation and reverse rotation of the rotation axis AX1 within a predetermined rotation angle range. As a result, the mirror 53 rotates relative to the rotating frame 52 within this range. On the other hand, the second solenoid 57 receives the control signal Sm2 from the outside and repeats normal rotation and reverse rotation of the rotation axis AX2 within a predetermined rotation angle range. As a result, the rotary frame 52 holding the mirror 53 rotates relatively to the support frame 51 within this range. That is, the mirror 53 of the projection unit 50 is configured to be rotatable in the V direction and the H direction with respect to the support frame 51 by receiving the control signals Sm1 and Sm2 from the outside. Has been done.

The laser light incident from the laser element 41 via the collimator lens 45 is reflected by the mirror 53 and irradiated toward the measurement range 80. The direction in which the laser beam is emitted is scanned within the measurement range 80 by changing the H direction and the V direction by rotating the mirror 53 of the projection unit 50. The direction in which the laser light is emitted by the reflection of the mirror 53 is also referred to as an irradiation direction. In this way, the optical system 30 can perform distance measurement within the measurement range 80 defined by the respective angle ranges of the V direction of laser light, that is, the vertical direction and the H direction, that is, the horizontal direction. If there is an object such as a person or a car, the laser light output from the optical distance measuring device 20 toward the measurement range 80 is diffusely reflected on the surface of the object, and part of the laser light returns toward the mirror 53 of the projection unit 50. Come on. The reflected light is reflected by the mirror 53, enters the light receiving lens 61 of the light receiving unit 60, is condensed by the light receiving lens 61, and enters the light receiving array 65.

The structure of the light receiving array 65 is schematically shown in FIG. The light-receiving array 65 is composed of a plurality of light-receiving elements 68 arranged so as to be H in the horizontal direction and V in the vertical direction. In this embodiment, each of the horizontal direction and the vertical direction is composed of five pieces, but may be composed of any number. The light receiving element 68 uses an avalanche photodiode (APD) in order to realize high response and excellent detection ability.

When a photon (photon) of the reflected light is incident on the APD, an electron/hole pair is generated, and the electron and the hole are accelerated by a high electric field, respectively, causing collision ionization to generate new electron/hole pairs. Generated (avalanche phenomenon). As described above, since the APD can amplify the incident photons, it is often used when the object is far and the intensity of the reflected light is small. The operation modes of the APD include a linear mode in which the reverse bias voltage is lower than the breakdown voltage and a Geiger mode in which the reverse bias voltage is higher than the breakdown voltage. In the linear mode, the number of electron-hole pairs that exit from the high electrolysis region and disappear is larger than the number of generated electron-hole pairs, and the collapse of electron-hole pairs naturally stops. Therefore, the output current from the APD is almost proportional to the amount of incident light. On the other hand, in the Gaiga mode, the avalanche phenomenon can occur even with the incidence of a single photon, so that the detection sensitivity can be further increased. Such an APD operated in the Gaiga mode may be referred to as a single photon avalanche diode (SPAD: Single Photon Avalanche Diode).

As shown in the equivalent circuit of FIG. 3, each light receiving element 68 has a quench resistor Rq and an avalanche diode Da connected in series between a power supply Vcc and a ground line, and the voltage at the connection point is set as a logical operation element. It is input to the inverting element INV, which is one of the two, and is converted into a digital signal whose voltage level is inverted. Since the output of the inverting element INV is connected to one input of the AND circuit SW, if the other input is at the high level H, it is directly output to the outside. The state of the other input of the AND circuit SW can be switched by the selection signal SC. The selection signal SC is used to specify from which light-receiving element 68 of the light-receiving array 65 the signal is to be read out, and therefore may be referred to as an address signal. When the avalanche diode Da is used in the linear mode and its output is treated as an analog signal, an analog switch may be used instead of the AND circuit SW. A PIN photodiode may be used instead of the avalanche diode Da.

If no light is incident on the light receiving element 68, the avalanche diode Da is kept in a non-conducting state. Therefore, the input side of the inverting element INV is held in the pulled-up state via the quench resistor Rq, that is, the high level H. Therefore, the output of the inverting element INV is kept at the low level L. When light is incident on each of the light receiving elements 68 from the outside, the avalanche diode Da is turned on by the incident photons (photons). As a result, a large current flows through the quench resistor Rq, the input side of the inverting element INV once becomes low level L, and the output of the inverting element INV is inverted to high level H. As a result of the large current flowing through the quench resistor Rq, the voltage applied to the avalanche diode Da drops, so that the power supply to the avalanche diode Da is stopped and the avalanche diode Da returns to the non-conducting state. As a result, the output signal of the inverting element INV is also inverted and returns to the low level L. As a result, the inverting element INV outputs a pulse signal that becomes high level for a very short time when a photon (photon) enters each light receiving element 68. Therefore, if the address signal SC is set to the high level H at the timing when each light receiving element 68 receives light, the output signal of the AND circuit SW, that is, the output signal Sout from each light receiving element 68, is output from the avalanche diode Da. The digital signal reflects the status.

The output signal Sout of each light receiving element 68 is generated when the laser element 41 emits light, and the light is reflected and returned to the object OBJ existing in the scanning range. Therefore, as shown in FIG. 4, after the light emitting unit 40 is driven and the laser light (hereinafter, also referred to as irradiation light pulse) is output, the reflected light pulse reflected by the object OBJ is received by each light receiving unit 60. By measuring the time Tf until the detection by the element 68, the distance to the target can be detected. The object OBJ can be present in various positions from near to far from the optical distance measuring device 20.

The light receiving element 68 outputs a pulse signal when receiving the reflected light, as described above. The pulse signal output from the light receiving element 68 is input to the SPAD calculation unit 100. The SPAD calculation unit 100 causes the laser element 41 to emit light to scan the external space, and at the time Tf from the time when the laser element 41 outputs the irradiation light pulse to the time when the light receiving array 65 of the light receiving unit 60 receives the reflected light pulse. To a target object OBJ. The SPAD calculation unit 100 includes a well-known CPU and memory, and executes a program prepared in advance to perform processing required for distance measurement. Specifically, the SPAD calculation unit 100 includes an addition unit 120, a histogram generation unit 130, a peak detection unit 140, a distance calculation unit 150, and the like, in addition to the control unit 110 that performs overall control.

The adding section 120 is a circuit that adds the outputs of a larger number of light receiving elements included in the light receiving element 68 that constitutes the light receiving section 60. N×N (N is an integer of 2 or more) light receiving elements are further provided inside the light receiving element 68, and when a reflected light pulse enters one light receiving element 68 forming the light receiving unit 60, N ×N elements operate. In this embodiment, 7×7 SPADs are provided in one light receiving element 68. Needless to say, the number and arrangement of SPADs can be variously configured, such as 5×9, other than 7×7.

In the present embodiment, the light receiving element 68 is composed of a plurality of SPADs due to the characteristics of the SPADs. The SPAD can detect only one photon incident, but the detection of the SPAD by the limited light from the object OBJ must be probabilistic. The addition unit 120 of the SPAD calculation unit 100 adds the output signal Sout from the SPAD that can detect the reflected light only stochastically and detects the reflected light. Of course, the light receiving element 68 may be composed of a single SPAD.

The histogram generation unit 130 receives the reflected light pulse thus obtained. The histogram generation unit 130 adds the addition results of the addition unit 120 a plurality of times to generate a histogram. Although the signal detected by the light receiving element 68 includes noise due to ambient light, etc., when the signals from the respective light receiving elements 68 for a plurality of irradiation light pulses are added together, the signal corresponding to the noise is hard to accumulate. On the other hand, since the signals corresponding to the reflected light pulse are accumulated, the signal corresponding to the reflected light pulse becomes clear. Therefore, the peak detection unit 140 detects the peak of the signal by analyzing the histogram from the histogram generation unit 130. The peak of the signal is nothing but the reflected light pulse from the object OBJ that is the object of distance measurement. When the peak is detected in this way, the distance calculation unit 150 detects the distance D to the object by detecting the time from the irradiation light pulse to the peak of the reflected light pulse. The detected distance D is output to the vehicle surroundings monitoring system 200 mounted on the vehicle 70 described later. In addition, the distance D may be output to, for example, an automatic driving device of an automatic driving vehicle equipped with the optical distance measuring device 20, or mounted on various moving bodies such as a drone, a train, and a ship in addition to the vehicle 70. Alternatively, it may be used alone as a fixed distance measuring device.

The control unit 110 generates a histogram in addition to the command signal SL for determining the light emission timing of the laser element 41 to the circuit board 43 of the light emitting unit 40, the address signal SC for determining which light receiving element 68 to activate, and the histogram generation. A signal St for instructing the generation timing of the histogram for the unit 130 and control signals Sm1, Sm2 for the

solenoids

55, 57 of the projection unit 50 are output. When the control unit 110 outputs these signals at a predetermined timing, the SPAD operation unit 100 detects the object OBJ existing in the measurement range 80 together with the distance D to the object OBJ.

Next, the measurement range 80 of the optical distance measuring device 20 will be described in detail with reference to FIGS. 5 to 7. As described above, the mirror 53 of the projection unit 50 is configured to be rotatable in the V direction and the H direction in response to the control signals Sm1 and Sm2 from the control unit 110. In FIG. 5, the scanning path in the irradiation direction of the mirror 53 is shown by being decomposed into each direction component of the V direction and the H direction. The time axes in the graphs of FIG. 5 are common to each other.

The upper graph in the figure shows the change in the rotation angle in the V direction of the irradiation direction of the mirror 53 with respect to the time axis. When the standard position of the mirror 53 is zero, the irradiation direction of the mirror 53 in the V direction is set in the angle range from the angle −V1 to the angle +V1. This angle range in the V direction is the maximum range in the vertical direction in which the optical distance measuring device 20 can perform distance measurement, and is also called a vertical optical angle. The lower graph in the figure represents the change in the rotation angle in the H direction of the irradiation direction of the mirror 53 with respect to the time axis. When the standard position of the mirror 53 is zero, the irradiation direction of the mirror 53 in the H direction is set within the angle range from the angle −H1 to the angle +H1. This angle range in the H direction is the maximum range in the horizontal direction in which the optical distance measuring device 20 can perform distance measurement, and is also called a horizontal optical angle.

When the irradiation direction of the mirror 53 is the angle −H1 in the H direction and the time when the V direction is zero is time t0, the mirror 53 starts rotating the V direction and the H direction to the plus side angles, respectively. .. In this embodiment, the angle of the mirror 53 is changed at a constant speed. When the time t1 is reached, the H direction reaches the angle +H1 and is rotated toward the minus side angle. When the time t2 is reached, the angle in the V direction reaches the angle +V1 and is rotated toward the minus side angle. When the time t3 is reached, the H direction reaches the angle −H1 and is rotated again toward the plus side angle, and the rotation directions are reversed at the time t4, the time t5, and the time t7. In this way, the irradiation direction of the mirror 53 is reciprocated three times from the angle −H1 to the angle +H1 in the H direction by the time t8. The single vibration having the amplitude of the angle H1 may be repeated three times in the H direction. On the other hand, the irradiation direction V reaches the time t6, reaches the angle −V1, is rotated toward the plus side angle, and returns to zero at the time t8. That is, the irradiation direction of the mirror 53 makes one round trip from the angle −V1 to the angle +V1 in the V direction by the time t8. The single vibration having the amplitude of the angle V1 may be performed once in the V direction. In this way, the mirror 53 makes three reciprocations in the H direction while making one reciprocation in the V direction. The vibration frequency of the mirror 53 in the H direction may be set as a single vibration that is three times the vibration frequency in the H direction.

FIG. 6 shows a path in the irradiation direction of the mirror 53 by the optical distance measuring device 20. That is, it shows a path in the irradiation direction obtained by synthesizing the angle change in each direction component of the H direction and the V direction of the mirror 53 from time t0 to time t8 shown in FIG. In the figure, each time t0 to t8 in FIG. 5 is shown at a corresponding position on the route in order to facilitate understanding of the technique. As described above, the mirror 53 completes one reciprocating operation from the angle −V1 to the angle +V1 in the V direction, and completes three reciprocating operations from the angle −H1 to the angle +H1 in the H direction. Therefore, as shown in FIG. 6, it becomes a figure in which three long rhombus shapes in the H direction are arranged in the vertical direction. The path in the irradiation direction by the mirror 53 may be a plane figure (also called a Lissajous figure) obtained by synthesizing two vibrations of a V direction component and an H direction component with an amplitude frequency ratio of 1:3.

Next, details of the measurement range 80 of the optical distance measuring device 20 will be described. The measurement range 80 is schematically shown on the right side of FIG. 7. The measurement range 80 shown on the right side of FIG. 7 is a state of being projected on a cylindrical screen. The cylindrical screen means a cylindrical flat surface whose axial direction is the V direction, as shown on the left side of FIG. 7. The measurement range 80 is set such that the standard position in the V direction of the irradiation direction of the mirror 53 is set to be parallel to the horizontal direction and is projected on a cylindrical screen surrounding the mirror 53 in the center. In the present embodiment, the standard position in the V direction of the irradiation direction of the mirror 53 is the center (zero) in the angular range of the V direction.

As shown on the right side of FIG. 7, in the shape of the measurement range 80, the width in the V direction at both ends in the H direction (angle −H1 and angle +H1 in the present embodiment) is the center of the measurement range 80 in the H direction. It is smaller than the width in the V direction. Such a shape is also referred to as an end narrow shape. The narrow end portion shape also includes a shape in which the width in the V direction at at least one end portion in the H direction is smaller than the width in the V direction at the center of the measurement range 80 in the H direction. The reason why the measuring range 80 has such a narrow end shape is that the irradiation light is scanned on the path of the shape shown in FIG.

Next, the vehicle periphery monitoring system 200 of the first embodiment equipped with the optical distance measuring device 20 will be described with reference to FIGS. 8 to 10. The vehicle periphery monitoring system 200 is a device that is mounted on a vehicle 70, which is an automobile, and detects an object around the vehicle 70. Hereinafter, the vehicle surroundings monitoring system 200 will be simply referred to as the monitoring system 200. As shown in FIG. 8, the monitoring system 200 includes two optical distance measuring devices, namely an optical distance measuring device 20 located on the left side in the traveling direction of the upper part of the vehicle 70 and an optical distance measuring device 22 located in the center of the upper part of the vehicle 70. An optical distance measuring device is provided. The monitoring system 200 receives the distance D of the object detected by each of the optical

distance measuring devices

20 and 22, and detects the presence or absence of the object around the vehicle 70.

The center optical distance measuring device 22 in the upper part of the vehicle 70 has a measuring range 82 different from the measuring range 80 of the optical distance measuring device 20, but other configurations are the same as the optical distance measuring device 20. Hereinafter, the optical distance measuring device 20 is also referred to as a first optical distance measuring device 20, and the optical distance measuring device 22 is also referred to as a second optical distance measuring device 22, and the measurement range 80 of the first optical distance measuring device 20 is referred to as a first measurement range 80. Also, the measurement range 82 of the second optical distance measuring device 22 is also referred to as a second measurement range 82. The irradiation light projected by the second optical distance measuring device 22 onto the second measurement range 82 is also referred to as second irradiation light, and the reflected light reflected from the second measurement range 82 is also referred to as second reflected light.

FIG. 9 shows a projection of the measurement range 82 of the second optical distance measuring device 22 on a cylindrical screen. The projection conditions are the same as the measurement range 80 of the first optical distance measuring device 20 described above. As shown in FIG. 9, the shape of the measurement range 82 of the second optical distance measuring device 22 is a substantially rectangular shape, and the width in the V direction at the center of the measurement range 82 in the H direction and at both ends in the H direction. The width in the V direction is substantially the same. The measurement range 82 has such a shape because the reflected light is scanned in a rectangular shape by the control of the mirror by the control unit of the second optical distance measuring device 22. It may be achieved by scanning the irradiation light having a vertically long light emitting region in the V direction in one direction of the H direction.

Next, the detection range of the object by the monitoring system 200 will be described. The detection range of the monitoring system 200 is the combined range of the measurement ranges 80 and 82 of the optical

distance measuring devices

20 and 22 that form the monitoring system 200. FIG. 8 is a front view of the detection range in the vertical direction of the monitoring system 200 viewed along the horizontal direction, and FIG. 10 is a perspective view of the detection system 200 in the horizontal direction centered on the vehicle 70. ..

As shown in FIG. 8, the detection range of the monitoring system 200 is configured such that the measurement range 80 of the first optical ranging device 20 includes a region outside the measurement range 82 of the second optical ranging device 22. FIG. 8 schematically shows the irradiation direction LD1 of the irradiation light measuring range 80 by the first optical distance measuring device 20 and the irradiation direction LD2 of the irradiation light measuring range 82 by the second optical distance measuring device 22. ing. In the present embodiment, the irradiation direction LD2 of the second optical distance measuring device 22 is set such that the depression angle is slightly smaller than the horizontal direction, but the irradiation direction LD2 of the second optical distance measuring device 22 is parallel to the horizontal direction. The direction may be set to. That is, in the present specification, the “depression angle of the irradiation direction LD2 of the second optical distance measuring device 22” also includes the horizontal direction. Since the measurement range 82 of the second optical distance measuring device 22 has the rectangular shape shown in FIG. 9, it is formed so as to extend in a concentric circle shape except the vicinity of the vehicle 70 on the horizontal plane Hz. By doing so, the second optical distance measuring device 22 detects all directions except the vicinity of the vehicle 70 as shown in FIG. 10.

On the other hand, the measurement range 80 of the first optical distance measuring device 20 is set to have a larger depression angle than the irradiation direction LD2 of the second optical distance measuring device 22, as shown in FIG. In other words, the irradiation direction LD1 of the first optical distance measuring device 20 is installed so as to be downward with respect to the irradiation direction LD2 of the second optical distance measuring device 22. When the angle between the irradiation direction LD1 and the irradiation direction LD2 is an angle θ1, the angle θ1 is 20 degrees in the present embodiment. By doing so, the measurement range 80 of the first optical distance measuring device 20 covers a region outside the measurement range below the measuring range 82 of the second optical distance measuring device 22.

The measurement range 80 of the first optical distance measuring device 20 is shown on the horizontal plane Hz as shown in FIG. The installation direction of the first optical distance measuring device 20 in the horizontal direction is set to be a direction perpendicular to the traveling direction of the vehicle 70 which travels straight. Here, in the case where the second optical distance measuring device 22 is provided in place of the first optical distance measuring device 20 of the monitoring system 200, the area 82t shown in FIG. 10 substitutes for this second optical distance measuring device 22. The measurement range is shown in FIG. The region 82t includes a region that is substantially the same as the measurement range 80 of the first optical distance measuring device 20, and further protrudes in a direction away from the second optical distance measuring device 22 toward both ends in the H direction (so-called butterfly shape). Shape) on the horizontal plane Hz. The reason why the shape protrudes toward both ends in the H direction is that the distance from the second optical distance measuring device 22 to the horizontal plane Hz becomes longer toward the both ends in the H direction.

On the other hand, as shown in FIG. 10, the measurement range 80 of the first optical distance measuring device 20 has a shorter protruding distance on both end sides in the H direction than the area 82t. Therefore, the overlapping range with the measurement range 82 of the second optical distance measuring device 22 is smaller than that of the region 82t. This is because the width of the vertical optical angle at both ends in the H direction of the measurement range 80 of the first optical distance measuring device 20 is the same as that at both ends of the measuring range 82 of the second optical distance measuring device 22 in the H direction. This is because the width is set smaller than the width of the vertical optical angle. In other words, the width in the vertical direction (V direction) at both ends in the H direction of the measurement range 80 of the first optical distance measuring device 20 is the same as the vertical direction (V direction) at the center in the horizontal direction (H direction). This is because it is set as an end narrower shape that is smaller than the width.

As described above, according to the vehicle periphery monitoring system 200 of the present embodiment, the first optical distance measuring device 20 individually scans the irradiation direction of the mirror 53 in each of the H direction and the V direction to thereby measure the measurement range. 80 has an end narrowed shape in which the width in the vertical direction at both ends in the horizontal direction is smaller than the width in the vertical direction at the center in the horizontal direction. As a result, it is possible to efficiently detect an object in the vicinity of the optical distance measuring device 20 or in the vicinity of the vehicle 70 in which the device is mounted. Further, it is possible to increase the density of the amount of irradiation light in the vicinity of the optical distance measuring device 20 and the vehicle 70, and improve the measurement accuracy.

According to the vehicle surroundings monitoring system 200 of the present embodiment, the measurement range 82 of the second optical distance measuring device 22 and the measurement range 80 of the first optical distance measuring device 20 in which the measurement directions are all directions of the vehicle 70 overlap. The number of parts can be reduced, and an object near the vehicle 70 can be efficiently detected. Further, the measurement accuracy can be increased by increasing the density of the irradiation light near the vehicle 70.

According to the vehicle periphery monitoring system 200 of the present embodiment, the mirror 53, which is a two-dimensional scanner, is adopted in the projection unit 50 of the first optical distance measuring device 20, so that the V direction and the H direction can be individually controlled easily. be able to. Further, by reducing the number of parts, the first optical distance measuring device 20 can be downsized.

B. Second embodiment:
The vehicle periphery monitoring system 200b of the second embodiment includes a first optical distance measuring device 20b instead of the first optical distance measuring device 20 of the first embodiment. As shown in FIG. 11, the optical distance measuring device 20b includes an optical system 30b in place of the optical system 30 of the optical distance measuring device 20 in the first embodiment, and other configurations are the optical measuring device in the first embodiment. It is similar to the distance device 20. The optical system 30b includes a light emitting unit 40b and a projection unit 50b.

The projection unit 50b is composed of a so-called one-dimensional scanner. The projection unit 50b includes a mirror 54 that reflects the irradiation light, a rotary solenoid 58, and a rotary unit 56 that rotates the mirror 54 in one direction by a rotary shaft that has the vertical direction as the axial direction by the rotary solenoid 58.

The light emitting section 40b differs from the light emitting section 40 in the first embodiment in that the light emitting area of the irradiation light is different. As shown in the lower side of FIG. 11, the irradiation region Lx is a vertically long rectangular region including the entire measurement region in the V direction. Therefore, in the present embodiment, it is possible to measure the measurement range 80b at one time only by providing the projection unit 50b that can scan the irradiation light in only one direction.

The light emitting section 40b includes a light emitting element array 42 including a plurality of light emitting diodes, as shown in FIG. The light emitting element array 42 is classified into a region La and a region Lb under the control of the control unit 110, and ON/OFF of the light emitting device array 42 is individually switched for each of the regions La and Lb by the control of the control unit 110. The region La is a region corresponding to the upper and lower ends in the V direction of the irradiation region Lx in the light emitting region of the light emitting element array 42, and the region Lb is located between the regions La and in the V direction of the irradiation region Lx. The area corresponding to the center.

FIG. 13 shows the relationship between the control in the scanning direction of the mirror 54 and the ON/OFF control of the light emitting element array 42 for each of the regions La and Lb. The upper side of FIG. 13 represents a temporal change in the irradiation direction of the mirror 54 of the projection unit 50b in the horizontal direction, and the lower side of FIG. 13 represents ON/OFF control of the light emitting elements for each of the regions La and Lb. ing. The time axes coincide with each other. As described above, in the present embodiment, the control unit 110 controls the control of the projection unit 50b in the scanning direction and the ON/OFF of the light emitting element array 42 for each of the regions La and Lb in synchronization.

When the irradiation direction of the mirror 54 at time t20 is the angle −H1, the control unit 110 controls the rotary solenoid 58 to rotate the mirror 54 toward the angle +H1 side via the rotating unit 56. At this time, the light emitting element array 42 in the region La is OFF and the light emitting element array 42 in the region Lb is ON. When the mirror 54 starts rotating and reaches the time t21, the control unit 110 transmits a control signal to turn on the light emitting element array 42 in the region La. When the time t22 is reached, the control unit 110 turns off the light emitting element array 42 in the region La. When the irradiation direction of the mirror 54 reaches the angle +H1 (time t23), the mirror 54 is rotated again toward the angle -H1, and at time t24, the mirror 54 reaches the angle -H1 and makes one round trip in the H direction. Complete the scan. During this period, the light emitting element array 42 in the area La is controlled to be turned on/off at the same timing as the control from the time t20 to the time t23. In the control of one reciprocating scan of the mirror 54, the light emitting element array 42 in the region Lb is always on. Note that the horizontal scanning of the mirror 54 need not be one reciprocal scanning as long as the detection accuracy is high, and may be controlled only during the period from time t20 to time t23.

FIG. 14 shows a measurement range 80b formed by controlling the above-described operation of the mirror 54 and ON/OFF of the light emitting element array 42 for each of the regions La and Lb. In the figure, each time t20 to t24 in FIG. 13 is shown at a corresponding position in order to facilitate understanding of the technique. The measurement range 80b shown in FIG. 14 is projected on a cylindrical screen, like the measurement range 80 in the first embodiment. The range irradiated by the region La of the light emitting element array 42 is defined as a range LaV, and the range irradiated by the region Lb is defined as a range LbV.

As described above, the light emitting element arrays 42 belonging to the area La are controlled to be turned off at both ends of the horizontal optical angle of the mirror 54 corresponding to the times t20 to t21 and the times t22 to t23. Therefore, in the measurement range 80b, only the range LbV is formed on both ends of the horizontal optical angle of the mirror 54, and the width in the V direction is shorter by the upper and lower range LaV. In this way, the width in the vertical direction at both ends of the measurement range 80b of the optical distance measuring device 20b in the horizontal direction is narrower than the width in the vertical direction at the center in the horizontal direction.

As described above, in the vehicle periphery monitoring system 200b of the second embodiment, in the first optical distance measuring apparatus 20b, the rotation control of the mirror 54 as the one-dimensional scanner and the synchronous control of ON/OFF of the light emitting element array 42 are performed. By doing so, the width in the vertical direction at both ends in the H horizontal direction of the measurement range 80b is made narrower at the end portion than the width in the vertical direction at the center in the horizontal direction. As a result, it is possible to reduce the output of the light emitting unit 40b and reduce the overlapping portion between the measurement range 82 of the second optical distance measuring device 22 and the measurement range 80b of the first optical distance measuring device 20b. An object near the vehicle 70 can be detected.

C. Third embodiment:
FIG. 15 shows the configuration of the first optical distance measuring device 20c included in the vehicle periphery monitoring system 200c of the third embodiment. The optical distance measuring device 20c is different from the first optical distance measuring device 20 in the first embodiment in that the optical system 30c is provided instead of the optical system 30. The optical system 30c is configured by a so-called diffusion optical system, and includes a light emitting unit 40c including a light emitting diode, a light receiving unit 60, and a light diffusing unit 44.

The light diffusing unit 44 is a light diffusing plate composed of a microlens array. The irradiation light of surface emission emitted from the light emitting diode of the light emitting section 40c is diffused at a predetermined angle when passing through the light diffusing section 44 to form a measurement range 80c. The shape of the measurement range 80c is the same as the shape of the measurement range 80 of the optical distance measuring device 20 in the first embodiment. The light diffusing unit 44 may be configured by arranging a plurality of lenses, or may be configured by various members such as a flat top diffusion plate, a diffraction grating, a hologram, and a film-shaped diffuser that diffuse the irradiation light from the light emitting unit 40c. Good. According to the vehicle periphery monitoring system 200c of the present embodiment, a simple method is used to measure an end narrowed shape in which the vertical widths at both ends in the horizontal direction are smaller than the vertical width at the center in the horizontal direction. It is possible to obtain the first optical distance measuring device 20c having the range 80c.

D. Fourth Embodiment:
In the first optical distance measuring device 20 included in the vehicle periphery monitoring system 200 of the first embodiment, the path of the mirror 53 in the irradiation direction is formed into a Lissajous figure shape so that the measurement range 80 can be located on the plus side and the minus side in the V direction. Although the shape is contracted to the zero side, as in the measurement range 80d shown in FIG. 16, the plus side in the V direction is curved and the minus side in the V direction is linear so that the measurement range 80d is horizontal. The width in the vertical direction at both end sides in the direction may be narrower than the width in the vertical direction at the center in the horizontal direction. Further, in the first optical distance measuring device 20b included in the vehicle periphery monitoring system 200b of the second embodiment, rotation control of the mirror 54 as a one-dimensional scanner and ON/OFF of the light emitting element arrays 42 in the upper and lower regions La in the V direction are performed. And are synchronously controlled, while ON/OFF of the light emitting element array 42 in the region La only on the upper side in the V direction is synchronously controlled, so that the narrow end shape like the measurement range 80d shown in FIG. May be

E. Other embodiments:
(E1) In the first embodiment, the mirror 53 completes one reciprocating motion from the angle −V1 to the angle +V1 in the V direction, while completing three reciprocating motions from the angle −H1 to the angle +H1 in the H direction. Let On the other hand, the path of the irradiation direction by the mirror 53 is the angular range (amplitude) in the V direction and the H direction, and the reciprocation in the V direction and the H direction so that the shape of the measurement range 80 has a narrow end shape. The vibration component such as the number of times (frequency) and the initial phase may be set arbitrarily. By adopting a Lissajous figure in the scanning path in the irradiation direction of the mirror 53, the vertical width at the both ends in the horizontal direction of the measurement range 80 can be made easier than the vertical width at the center in the horizontal direction by a simple method. It is possible to obtain a narrow end shape.

(E2) In each of the above-described embodiments, the measurement range is formed as an end narrowed shape in which the width in the V direction at both ends in the H direction is smaller than the width in the V direction at the center in the H direction. On the other hand, the end narrowed shape may be a shape in which the width in the V direction on one of the end sides in the H direction is smaller than the width in the V direction at the center in the H direction. In such an aspect, the installation direction of the first optical distance measuring device 20 installed in the vehicle 70 in the horizontal direction is the traveling direction side or the opposite direction with respect to the direction perpendicular to the traveling direction in which the vehicle 70 travels straight. The width in the V direction corresponding to the end portion side in the H direction that reduces the overlap with the measurement range 82 of the second optical distance measuring device 22 when set to the side in the V direction at the center in the H direction By making the width smaller than the width, it is possible to efficiently detect the object.

(E3) In the first embodiment, the rotation axes of the mirror 53 are orthogonal to each other in the horizontal direction and the vertical direction, but may be in an aspect in which they are not orthogonal and intersect at an arbitrary angle.

(E4) The narrow end portion shape may be formed by changing the shape of the light emitting portion.

(E5) In each of the above embodiments, the vehicle periphery monitoring system includes two optical distance measuring devices, the first optical distance measuring device 20 and the second optical distance measuring device 22. For example, on the right side of the upper portion of the vehicle 70. The number of optical distance measuring devices is not limited to two, and may be three or more.

The present disclosure is not limited to the above-described embodiment, and can be realized with various configurations without departing from the spirit of the present disclosure. For example, the technical features of the embodiment corresponding to the technical features in each mode described in the section of the summary of the invention are to solve some or all of the above problems, or some of the above effects. Alternatively, in order to achieve all, it is possible to appropriately replace or combine. If the technical features are not described as essential in the present specification, they can be deleted as appropriate.

Claims

A vehicle periphery monitoring system (200, 200b, 200c),
A light emitting unit (40, 40b, 40c) that emits irradiation light, and receives reflected light from the measurement range of the irradiation light projected toward a predetermined measurement range (80, 80b, 80c, 80d) Then, using the light receiving unit (60) that outputs a signal according to the light receiving state of the reflected light and the signal output from the light receiving unit, the measurement for measuring the distance to the object included in the measurement range. A first optical distance measuring device including a section (100), and the irradiation light is projected in a horizontal direction on a cylindrical plane surrounding the first optical distance measuring device along a vertical direction. When the shape of the measurement range, the width in the vertical direction at least one end in the horizontal direction of the measurement range is an end narrowed shape smaller than the width in the vertical direction at the center in the horizontal direction, the first Optical distance measuring device (20, 20b, 20c),
The second irradiation light projected toward the predetermined second measurement range (82) is received as the second reflected light from the second measurement range, and a signal corresponding to the light receiving state of the second reflected light is received. A second optical distance measuring device for measuring a distance to an object included in the second measurement range, wherein the second irradiation light projected toward the second measurement range is the second light. The shape of the second measurement range when projected along the horizontal direction on a cylindrical plane along the vertical direction surrounding the distance measuring device has a width in the vertical direction at the horizontal center of the second measurement range. Is the same as the width in the vertical direction at both ends in the horizontal direction, and a second optical distance measuring device (22),
The first optical distance measuring device and the second optical distance measuring device,
The vehicle (70) so that the depression angle in the irradiation direction (LD1) of the irradiation light by the first optical distance measuring device is larger than the depression angle in the irradiation direction (LD2) of the second irradiation light by the second optical distance measuring device. ),
Vehicle surroundings monitoring system.
The first optical distance measuring device further includes a projection unit (50) that projects the irradiation light toward the measurement range,
The vehicle periphery monitoring system according to claim 1, wherein the projection unit includes a reflection unit (53) that rotates about at least two central axes and reflects the irradiation light.
The vehicle periphery according to claim 2, wherein the reflecting portion has two central axes that are orthogonal to each other, and realizes the narrow end shape by rotating while changing a vibration component on each of the two central axes. Monitoring system.
The vehicle periphery monitoring system according to claim 1,
The first optical distance measuring device,
A projection unit (50b) including a reflection unit (53) that reflects the irradiation light while rotating in one direction, and projects the irradiation light along the horizontal direction toward the measurement range;
The light emitting unit,
A plurality of light emitting elements (42), which can be individually turned on/off and are arranged in a direction corresponding to the vertical optical angle of the measurement range,
At least one end in the horizontal direction of the measurement range, the light emitting element corresponding to the end including at least the upper end side in the vertical direction of the vertical optical angles of the measurement range is turned off,
At the center of the measurement range in the horizontal direction, the end narrowed shape is realized by turning on the light emitting element corresponding to the end.
Vehicle surroundings monitoring system.
The vehicle periphery monitoring system according to claim 1,
The first optical distance measuring device further includes a light diffusing unit (44) for diffusing the irradiation light,
The light diffusing section, in the horizontal center of the measurement range, realizes the narrow end shape by diffusing light more than at least one end in the horizontal direction of the measurement range,
Vehicle surroundings monitoring system.