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WO2020133384A1 - 一种激光测距装置及移动平台 - Google Patents

一种激光测距装置及移动平台 Download PDF

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Publication number
WO2020133384A1
WO2020133384A1 PCT/CN2018/125452 CN2018125452W WO2020133384A1 WO 2020133384 A1 WO2020133384 A1 WO 2020133384A1 CN 2018125452 W CN2018125452 W CN 2018125452W WO 2020133384 A1 WO2020133384 A1 WO 2020133384A1
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WO
WIPO (PCT)
Prior art keywords
laser
measuring device
distance measuring
polarized light
linearly polarized
Prior art date
Application number
PCT/CN2018/125452
Other languages
English (en)
French (fr)
Inventor
王栗
董帅
洪小平
Original Assignee
深圳市大疆创新科技有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 深圳市大疆创新科技有限公司 filed Critical 深圳市大疆创新科技有限公司
Priority to CN201880069663.5A priority Critical patent/CN111712734A/zh
Priority to PCT/CN2018/125452 priority patent/WO2020133384A1/zh
Publication of WO2020133384A1 publication Critical patent/WO2020133384A1/zh

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B11/00—Measuring arrangements characterised by the use of optical techniques
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
    • G01C3/00—Measuring distances in line of sight; Optical rangefinders
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems

Definitions

  • the invention generally relates to the technical field of distance measuring devices, and more particularly to a laser distance measuring device and a mobile platform.
  • the laser ranging device of lidar plays an important role in many fields, for example, it can be used on mobile platforms or non-mobile platforms for remote sensing, obstacle avoidance, mapping, modeling, etc.
  • the lidar based on the principle of time of flight (TOF) as an example, the lidar emits laser pulses outwards and receives echoes generated by the reflection of external objects. By measuring the delay of the echo, the distance between the object and the lidar in this emission direction can be calculated. By dynamically adjusting the laser emission direction, it is possible to measure the distance information between objects of different orientations and lidar, so as to realize the modeling of three-dimensional space.
  • TOF time of flight
  • the present invention has been proposed to solve at least one of the above problems.
  • the present invention provides a laser ranging device, the laser ranging device includes a transmitting module, the transmitting module is used to emit a laser pulse to detect the object to be measured, wherein the laser pulse is linearly polarized light
  • the polarization direction of the linearly polarized light is parallel to the plane formed by the emission direction of the linearly polarized light and the normal direction of the interference surface, and the interference surface includes a water surface or an ice surface.
  • the emitting module includes a laser for emitting the linearly polarized light, and the laser is placed at an angle such that the polarization direction of the linearly polarized light is parallel to the emission of the linearly polarized light The plane formed by the direction and the normal of the interference surface.
  • the transmitting module includes a laser and a half-wave plate disposed in front of the laser, wherein the laser is used to emit linearly polarized light, and the polarization direction of the linearly polarized light is perpendicular to the linear polarization A plane formed by the light emission direction and the normal direction of the interference surface, the half-wave plate is used to rotate the polarization direction of the linearly polarized light emitted by the laser by 90°, so that the polarization of the rotated linearly polarized light The direction is parallel to the plane formed by the emission direction of the linearly polarized light and the normal direction of the interference surface.
  • the emitting module includes a laser and a polarizer disposed in front of the laser, the laser is used to emit partially polarized light, and the polarizer allows the partially polarized light to pass through the The polarizer then becomes the linearly polarized light.
  • the laser includes a semiconductor laser.
  • the laser distance measuring device further includes a detection module for receiving the light beam reflected by the object to be measured and converting it into an electrical signal, and determining the object to be measured and the laser according to the electrical signal Distance between distance measuring devices.
  • the laser ranging device includes a laser radar.
  • the laser distance measuring device further includes: a scanning module
  • the transmitting module is used to transmit a laser pulse sequence to the scanning module, the scanning module is used to change the transmission direction of the laser pulse sequence and then exit, and the laser pulse sequence reflected back by the object to be measured passes through the scanning module It is incident on the detection module, and the detection module is used to determine the distance and/or direction of the object to be measured relative to the laser ranging device according to the reflected laser pulse sequence.
  • Another aspect of the present invention provides a mobile platform, the mobile platform comprising: any one of the laser distance measuring devices described above; and a platform body, the laser distance measuring device is mounted on the platform body.
  • the mobile platform includes at least one of a car, a remote control car, or a robot.
  • the laser distance measuring device of the present invention reduces the misdetection caused by the water surface or ice surface by making the polarization direction of the outgoing light parallel to the reflection plane, thereby improving the reliability of the laser distance measuring device.
  • FIG. 1 shows a schematic diagram of the mis-detection of the laser ranging device caused by water or ice
  • FIG. 2 shows a schematic diagram of the optical path of the laser distance measuring device provided by the first embodiment of the present invention
  • FIG. 3 shows a curve of the reflectance of the p-wave emitted by the laser ranging device provided by the embodiment of the present invention and the s-wave emitted by the control group with the incident angle;
  • FIG. 4 shows the change curve of the reflectance of the p-wave emitted by the laser ranging device provided by the embodiment of the present invention and the s-wave emitted by the control group with the reflection distance;
  • FIG. 5 shows a schematic diagram of the optical path of the laser distance measuring device provided by the second embodiment of the present invention.
  • FIG. 6 shows a schematic diagram of the optical path of the laser distance measuring device provided by the third embodiment of the present invention.
  • FIG. 7 is a schematic frame diagram of a laser distance measuring device according to an embodiment of the present invention.
  • FIG. 8 is a schematic diagram of an embodiment of a laser distance measuring device provided by an embodiment of the present invention using a coaxial optical path.
  • the laser pulse 102 emitted by the laser distance measuring device 101 hits the water surface or the ice surface 103, a specular reflection occurs, and the reflected light 104 hits the falsely detected object 105, and the generated echo 106
  • the mirror reflection will occur again on the water surface or ice surface 103, and the generated reflected light 107 is finally received by the laser ranging device 101, resulting in a misdetection of the laser ranging device 101, that is, a misdetection of the position of the misdetected object 105 as a misdetected position 108 locations, which greatly affects the reliability of the laser distance measuring device 101.
  • the present invention provides a laser ranging device, the laser ranging device includes a transmitting module, the transmitting module is used to emit a laser pulse to detect the object to be measured, wherein the laser pulse is linearly polarized For light, the polarization direction of the linearly polarized light is parallel to the plane formed by the emission direction of the linearly polarized light and the normal direction of the interference surface, and the interference surface includes a water surface or an ice surface.
  • the laser distance measuring device of the present invention reduces the misdetection caused by the water surface or ice surface by making the polarization direction of the outgoing light parallel to the reflection plane, thereby improving the reliability of the laser distance measuring device.
  • the laser distance measuring device 200 of the present invention includes a transmitting module 210 for transmitting a laser pulse sequence.
  • the laser distance measuring device 200 may be a laser radar, or other suitable laser scanning device.
  • the laser pulse 203 emitted by the emitting module 210 is linearly polarized light, that is, the light vector only vibrates along a fixed direction.
  • the polarization direction of the linearly polarized light is parallel to the plane formed by the emission direction of the linearly polarized light and the normal 205 of the interference surface 204, and the interference surface 204 includes a water surface or an ice surface, that is, the interference surface is generally a horizontal surface .
  • the laser pulse 203 emitted by the emitting module 210 is a p-wave (that is, the polarization direction is parallel to the reflecting surface, and the reflecting surface refers to the plane formed by the incident light and the reflected light).
  • the emitting module 210 may include a laser, where the laser may be a semiconductor laser (or called a laser diode), for example, may be a positive-intrinsic-negative (PIN) photodiode, and the laser may emit a laser pulse of a specific wavelength Sequence, the laser tube can be called a light source or an emitting light source.
  • the laser may be a semiconductor laser (or called a laser diode), for example, may be a positive-intrinsic-negative (PIN) photodiode, and the laser may emit a laser pulse of a specific wavelength Sequence
  • the laser tube can be called a light source or an emitting light source.
  • the transmitting module 210 further includes a switching device and a driver.
  • the switching device is a switching device of a laser tube, which can be connected to the laser to control the switching of the laser, wherein, when the laser is on, the laser pulse sequence can be emitted, and when the laser is off, the laser pulse sequence is not emitted.
  • the driver can be connected to the switching device and used to drive the switching device.
  • the switching device may be a metal-oxide-semiconductor (MOS) tube, and the driver may include a MOS driver.
  • MOS driver may be used for Drive the MOS tube as a switching element.
  • the MOS tube can control the switching of the laser tube.
  • the switching device may also be a gallium nitride (GaN) tube, and the driver may be a GaN driver.
  • GaN gallium nitride
  • the laser 201 is used to emit the linearly polarized light. That is, the laser pulse 203 emitted by the laser 201 is linearly polarized light, and the polarization direction of the linearly polarized light is parallel to the plane formed by the emission direction of the linearly polarized light and the normal direction of the interference surface 204. Since the interference surface 204 is generally a horizontal plane, it can be considered that the plane formed by the polarization direction and the propagation direction of the laser pulse 203 is a vertical plane. Exemplarily, the placement angle of the laser 201 may be adjusted so that the polarization direction of the linearly polarized light emitted is parallel to the plane formed by the emission direction and the normal direction of the interference surface 204.
  • the laser 201 includes the above-mentioned semiconductor laser, the light emitting surface of the semiconductor laser is rectangular, the outgoing light is linearly polarized light, and its polarization direction is parallel to the short side of the rectangular light emitting surface.
  • the short side of the light emitting surface of the semiconductor laser is placed perpendicular to the horizontal plane, and the optical path at this time is shown in FIG. 2.
  • the polarization direction of the output light of the laser distance measuring device 200 incident on the water surface or ice surface 102 is parallel to the reflection surface (that is, the plane formed by the emission direction of the output light and the normal direction of the water surface or ice surface), in other words ,
  • the outgoing light is p wave.
  • the laser 201 may also be any suitable laser capable of emitting linearly polarized light, and the angle of its placement makes the linearly polarized light emitted p-wave.
  • the short side of the light emitting surface of the semiconductor laser is placed parallel to the horizontal plane as a control group.
  • the polarization direction of the outgoing light at this time is perpendicular to the reflecting surface, that is, the outgoing light is an s-wave.
  • i 1 is the angle of incidence and i 2 is the angle of refraction.
  • the curve of the reflectance of the p-wave and s-wave with the reflection distance is shown in FIG. 4, wherein the reflection distance is the output of the laser distance measuring device.
  • the reflectivity of the p-wave is less than the s-wave, and the reflection effect is particularly significant when the reflection distance is less than 10 meters.
  • the polarization direction of the outgoing light is parallel to the plane formed by the outgoing direction and the reflecting direction, so that the incident light surface The reflectivity of the outgoing light of the laser distance measuring device is greatly reduced.
  • the emitting module 210 includes a laser 201 and a half-wave plate 206 disposed in front of the laser 201, wherein the laser 201 is used to emit linearly polarized light ,
  • the polarization direction of the linearly polarized light is perpendicular to the plane formed by the emission direction of the linearly polarized light and the normal direction of the interference surface, and the half-wave plate 206 is used to convert the linearly polarized light emitted by the laser
  • the polarization direction is rotated by 90°, so that the polarization direction of the linearly polarized light after the rotation is parallel to the plane formed by the emission direction of the linearly polarized light and the normal direction of the interference surface.
  • a half-wave can be provided in front of the laser 201 Sheet 206 to change its polarization direction. After the polarized light passes through the half-wave plate 206, its outgoing light is still polarized light, and the polarization direction is rotated by an angle 2 ⁇ , where the angle ⁇ is the angle between the polarization direction of the incident light and the optical axis of the polarizer.
  • the laser 201 may be a semiconductor laser (or referred to as a laser diode), for example, a positive-intrinsic-negative (PIN) photodiode.
  • the light emitting surface of the semiconductor laser is rectangular, and the outgoing light is linearly polarized light, and its polarization direction is parallel to the short side of the rectangular light emitting surface. Due to the limitation of external factors, such as the overall structure of the laser distance measuring device, the short side of the light emitting surface of the semiconductor laser is placed parallel to the horizontal plane, and the emitted laser pulse is an s-wave.
  • the polarization direction of the laser pulse emitted by the laser 201 can be rotated by 90 degrees. It can be understood that after the polarization direction of the laser pulse is rotated by 90 degrees, the polarization direction changes from perpendicular to the reflection surface to parallel to the reflection surface, that is, the s-wave changes to the p-wave.
  • the emitting module 210 includes a laser 201 and a polarizer 207 disposed in front of the laser 201.
  • the laser 201 is used to emit partially polarized light.
  • the polarizer 207 makes the partially polarized light pass through the polarizer 207 and becomes the linearly polarized light.
  • the polarizer 207 is used to make the light wave incident on the water surface p-wave.
  • the degree of polarization is the proportion of fully polarized light in the total intensity of partially polarized light.
  • the polarizer 207 may be any suitable device for obtaining linearly polarized light from partially polarized light, including but not limited to polarizers, Nicols, and the like. By adjusting the vibration transmission direction of the polarizer 207, the polarization direction of the laser pulse 203 transmitted through the polarizer 207 can be parallel to the reflection surface.
  • the above embodiments of the present invention provide several structures for making the emitted light of the transmitting module 210 p-waves. However, it should be understood that the present invention is not limited to this. In addition to the above structures, other embodiments of the present invention may also be used.
  • the light emitted from the transmitting module 210 has a p-wave structure.
  • the laser distance measuring device 200 further includes a scanning module 202 for changing the transmission direction of the laser pulse sequence emitted by the transmitting module and then exiting, and reflecting the laser pulse sequence reflected by the object to be measured Incident to the detection module.
  • the scanning module only changes the transmission direction of the laser pulse without changing the polarization direction of the laser pulse.
  • the scanning module 202 may include at least one optical element for changing the propagation path of the light beam, wherein the optical element may change the propagation path of the light beam by reflecting, refracting, diffracting, etc. the light beam.
  • the scanning module 202 includes a lens, a mirror, a prism, a galvanometer, a grating, a liquid crystal, an optical phased array (Optical Phased Array), or any combination of the above optical elements.
  • at least part of the optical element is moving, for example, the at least part of the optical element is driven to move by a driving module, and the moving optical element can reflect, refract or diffract the light beam to different directions at different times.
  • multiple optical elements of the scanning module 202 may rotate or vibrate about a common axis, and each rotating or vibrating optical element is used to continuously change the propagation direction of the incident light beam.
  • the multiple optical elements of the scanning module 202 may rotate at different rotation speeds, or vibrate at different speeds.
  • at least part of the optical elements of the scanning module 202 can rotate at substantially the same rotational speed.
  • the multiple optical elements of the scanning module may also rotate around different axes.
  • multiple optical elements of the scanning module may also rotate in the same direction, or rotate in different directions; or vibrate in the same direction, or vibrate in different directions, which is not limited herein.
  • the laser ranging device 200 further includes a collimating lens and a converging lens
  • the collimating lens is located on the emitting optical path of the emitting circuit, and is used to collimate the laser pulse sequence emitted by the emitting circuit from The distance measuring device exits, and the converging lens is used for at least a part of the return light reflected by the convergent body.
  • the collimating lens and the converging lens may be two independent convex lenses, or the collimating lens and the converging lens may be the same lens, for example, the same convex lens.
  • the laser distance measuring device 200 further includes a detection module for receiving a laser pulse sequence reflected back by the object, and determining the object relative to the distance measuring device according to the reflected laser pulse sequence Distance and/or bearing. Since the laser pulse emitted by the transmitting module 210 is p light, the reflectivity of the interference surface is reduced, thereby greatly reducing the possibility that the reflected light causes the detection module to generate a false detection.
  • the detection module may include a receiving module, a sampling module, and an arithmetic module.
  • the receiving module is used to convert the received laser pulse sequence reflected back by the object into an electrical signal output; the sampling module is used for the receiving module The output electrical signal is sampled to measure the time difference between transmission and reception of the laser pulse sequence; the operation module is used to receive the time difference output by the sampling module and calculate and obtain a distance measurement result.
  • the detection module and the transmission module 210 may be collectively referred to as a ranging module.
  • the laser distance measuring device 200 further includes a control module for controlling the frequency of the laser pulse sequence emitted by the transmitting module.
  • the laser distance measuring device of the embodiment of the present invention reduces the misdetection caused by the water surface or the ice surface by making the polarization direction of the outgoing light parallel to the reflection plane, thereby improving the reliability of the laser distance measuring device.
  • an embodiment of the present invention further provides a mobile platform, the mobile platform includes any of the foregoing laser distance measuring devices and a platform body, and the laser distance measuring device is installed on the platform body.
  • the mobile platform includes at least one of a car, a robot, and a remote control car.
  • the platform body is the body of the automobile.
  • the car may be a self-driving car or a semi-automatic car, and no restriction is made here.
  • the distance measuring device is applied to a remote control car
  • the platform body is the body of the remote control car.
  • the platform body is a robot.
  • the platform body is the camera itself.
  • the laser distance measuring device provided by each embodiment of the present invention may be an electronic device such as a laser radar or a laser distance measuring device.
  • the distance measuring device is used to sense external environment information, for example, distance information, azimuth information, reflection intensity information, speed information, etc. of the environmental target.
  • the distance measuring device can detect the time of light propagation between the distance measuring device and the object to be measured, that is, time-of-light (TOF), to detect the object to be measured to the distance measuring device.
  • TOF time-of-light
  • the distance measuring device can also detect the distance between the object to be measured and the distance measuring device through other techniques, such as a distance measuring method based on phase shift measurement, or a distance measuring method based on frequency shift measurement, There are no restrictions here.
  • the laser distance measuring device 700 may include a transmitting circuit 710, a receiving circuit 720, a sampling circuit 730 and an arithmetic circuit 740.
  • the transmitting circuit 710 may transmit a laser pulse sequence (for example, a laser pulse sequence).
  • the receiving circuit 720 can receive the laser pulse sequence reflected by the object to be measured, and photoelectrically convert the optical pulse sequence to obtain an electrical signal, which can be output to the sampling circuit 730 after processing the electrical signal.
  • the sampling circuit 730 may sample the electrical signal to obtain the sampling result.
  • the arithmetic circuit 740 may determine the distance between the laser distance measuring device 700 and the object to be measured based on the sampling result of the sampling circuit 730.
  • the laser distance measuring device 700 may further include a control circuit 750, which can control other circuits, for example, can control the working time of each circuit and/or set parameters for each circuit.
  • a control circuit 750 can control other circuits, for example, can control the working time of each circuit and/or set parameters for each circuit.
  • the laser distance measuring device shown in FIG. 7 includes a transmitting circuit, a receiving circuit, a sampling circuit, and an arithmetic circuit for emitting a beam of light for detection
  • the number of any one of the circuit, the receiving circuit, the sampling circuit, and the arithmetic circuit may also be at least two, for emitting at least two light beams in the same direction or respectively in different directions; wherein, the at least two light paths may be Simultaneous shots can also be shot at different times.
  • the light-emitting chips in the at least two emission circuits are packaged in the same module.
  • each emitting circuit includes a laser emitting chip, and the die in the laser emitting chips in the at least two emitting circuits are packaged together and accommodated in the same packaging space.
  • the laser distance measuring device 700 may further include a scanning module for changing at least one laser pulse sequence emitted by the transmitting circuit to change the propagation direction.
  • the module including the transmitting circuit 710, the receiving circuit 720, the sampling circuit 730, and the arithmetic circuit 740, or the module including the transmitting circuit 710, the receiving circuit 720, the sampling circuit 730, the arithmetic circuit 740, and the control circuit 750 may be referred to as a measurement Distance module, the distance measuring module 750 may be independent of other modules, for example, a scanning module.
  • a coaxial optical path may be used in the distance measuring device, that is, the light beam exiting the distance measuring device and the reflected light beam share at least part of the optical path in the distance measuring device.
  • the distance measuring device may also adopt an off-axis optical path, that is, the light beam emitted by the distance measuring device and the reflected light beam are transmitted along different optical paths in the distance measuring device.
  • FIG. 8 shows a schematic diagram of an embodiment of the laser distance measuring device of the present invention using a coaxial optical path.
  • the laser distance measuring device 800 includes a distance measuring module 801, and the distance measuring module 801 includes a transmitter 803 (which may include the above-mentioned transmitting circuit), a collimating element 804, and a detector 805 (which may include the above-mentioned receiving circuit, sampling circuit, and arithmetic circuit) ⁇ 806.
  • the ranging module 801 is used to emit a light beam, and receive back light, and convert the back light into an electrical signal.
  • the transmitter 803 may be used to transmit a laser pulse sequence.
  • the transmitter 803 may emit a sequence of laser pulses.
  • the laser beam emitted by the transmitter 803 is a narrow-bandwidth beam with a wavelength outside the visible light range.
  • the collimating element 804 is disposed on the exit optical path of the emitter, and is used to collimate the light beam emitted from the emitter 803, and collimate the light beam emitted from the emitter 803 into parallel light to the scanning module.
  • the collimating element is also used to converge at least a part of the return light reflected by the object to be measured.
  • the collimating element 804 may be a collimating lens or other element capable of collimating the light beam.
  • the optical path changing element 806 is used to combine the transmitting optical path and the receiving optical path in the distance measuring device before the collimating element 804, so that the transmitting optical path and the receiving optical path can share the same collimating element, so that the optical path More compact.
  • the transmitter 803 and the detector 805 may respectively use respective collimating elements, and the optical path changing element 806 is disposed on the optical path behind the collimating element.
  • the light path changing element can use a small-area mirror to convert The transmitting optical path and the receiving optical path are combined.
  • the light path changing element may also use a reflector with a through hole, where the through hole is used to transmit the outgoing light of the emitter 803, and the reflector is used to reflect the return light to the detector 805. This can reduce the blocking of the return light by the support of the small mirror in the case of using the small mirror.
  • the optical path changing element is offset from the optical axis of the collimating element 804. In some other implementations, the optical path changing element may also be located on the optical axis of the collimating element 804.
  • the laser distance measuring device 800 further includes a scanning module 802.
  • the scanning module 802 is placed on the exit optical path of the distance measuring module 801.
  • the scanning module 802 is used to change the transmission direction of the collimated light beam 819 emitted through the collimating element 804 and project it to the outside environment, and project the return light to the collimating element 804 .
  • the returned light is converged on the detector 805 via the collimating element 804.
  • the scanning module 802 may include at least one optical element for changing the propagation path of the light beam, wherein the optical element may change the propagation path of the light beam by reflecting, refracting, diffracting, etc. the light beam.
  • the scanning module 802 includes a lens, a mirror, a prism, a galvanometer, a grating, a liquid crystal, an optical phased array (Optical Phased Array), or any combination of the above optical elements.
  • at least part of the optical element is moving, for example, the at least part of the optical element is driven to move by a driving module, and the moving optical element can reflect, refract or diffract the light beam to different directions at different times.
  • multiple optical elements of the scanning module 802 may rotate or vibrate about a common rotation axis 809, and each rotating or vibrating optical element is used to continuously change the propagation direction of the incident light beam.
  • the multiple optical elements of the scanning module 802 may rotate at different rotation speeds, or vibrate at different speeds.
  • at least part of the optical elements of the scanning module 802 can rotate at substantially the same rotational speed.
  • the multiple optical elements of the scanning module may also rotate around different axes.
  • multiple optical elements of the scanning module may also rotate in the same direction, or rotate in different directions; or vibrate in the same direction, or vibrate in different directions, which is not limited herein.
  • the scanning module 802 includes a first optical element 814 and a drive 816 connected to the first optical element 814.
  • the drive 816 is used to drive the first optical element 814 to rotate about a rotation axis 809 to change the first optical element 814 The direction of the collimated beam 819.
  • the first optical element 814 projects the collimated light beam 819 in different directions.
  • the angle between the direction of the collimated light beam 819 changed by the first optical element and the rotation axis 809 changes as the first optical element 814 rotates.
  • the first optical element 814 includes a pair of opposed non-parallel surfaces through which the collimated light beam 819 passes.
  • the first optical element 814 includes a prism whose thickness varies along at least one radial direction.
  • the first optical element 814 includes a wedge-angle prism that aligns the straight beam 819 for refraction.
  • the scanning module 802 further includes a second optical element 815.
  • the second optical element 815 rotates about a rotation axis 809.
  • the rotation speed of the second optical element 815 is different from the rotation speed of the first optical element 814.
  • the second optical element 815 is used to change the direction of the light beam projected by the first optical element 814.
  • the second optical element 815 is connected to another driver 817, and the driver 817 drives the second optical element 815 to rotate.
  • the first optical element 814 and the second optical element 815 may be driven by the same or different drivers, so that the rotation speed and/or rotation of the first optical element 814 and the second optical element 815 are different, thereby projecting the collimated light beam 819 to the outside space Different directions can scan a larger spatial range.
  • the controller 818 controls the drivers 816 and 817 to drive the first optical element 814 and the second optical element 815, respectively.
  • the rotation speeds of the first optical element 814 and the second optical element 815 may be determined according to the area and pattern expected to be scanned in practical applications.
  • Drives 816 and 817 may include motors or other drives.
  • the second optical element 815 includes a pair of opposing non-parallel surfaces through which the light beam passes. In one embodiment, the second optical element 815 includes a prism whose thickness varies along at least one radial direction. In one embodiment, the second optical element 815 includes a wedge angle prism.
  • the scanning module 802 further includes a third optical element (not shown) and a driver for driving the third optical element to move.
  • the third optical element includes a pair of opposed non-parallel surfaces through which the light beam passes.
  • the third optical element includes a prism whose thickness varies along at least one radial direction.
  • the third optical element includes a wedge angle prism. At least two of the first, second, and third optical elements rotate at different rotational speeds and/or turns.
  • each optical element in the scanning module 802 can project light into different directions, such as directions 811 and 813, so that the space around the laser distance measuring device 800 is scanned.
  • directions 811 and 813 the space around the laser distance measuring device 800 is scanned.
  • the reflected light 812 reflected by the object to be measured 810 passes through the scanning module 802 and enters the collimating element 804.
  • the detector 805 is placed on the same side of the collimating element 804 as the transmitter 803.
  • the detector 805 is used to convert at least part of the returned light passing through the collimating element 804 into an electrical signal.
  • each optical element is coated with an antireflection coating.
  • the thickness of the antireflection film is equal to or close to the wavelength of the light beam emitted by the emitter 803, which can increase the intensity of the transmitted light beam.
  • a filter layer is plated on the surface of an element on the beam propagation path in the distance measuring device, or a filter is provided on the beam propagation path to transmit at least the wavelength band of the beam emitted by the transmitter, Reflect other bands to reduce the noise caused by ambient light to the receiver.
  • the transmitter 803 may include a laser diode through which laser pulses in the order of nanoseconds are emitted.
  • the laser pulse receiving time may be determined, for example, by detecting the rising edge time and/or the falling edge time of the electrical signal pulse. In this way, the laser distance measuring device 800 can use the pulse receiving time information and the pulse sending time information to calculate the TOF, thereby determining the distance between the object to be measured 810 and the laser distance measuring device 800.
  • the distance and orientation detected by the laser distance measuring device 800 can be used for remote sensing, obstacle avoidance, mapping, modeling, navigation, and the like.
  • the distance measuring device of the embodiment of the present invention can be applied to a mobile platform, and the distance measuring device can be installed on the platform body of the mobile platform.
  • a mobile platform with a distance-measuring device can measure the external environment, for example, measuring the distance between the mobile platform and obstacles for obstacle avoidance and other purposes, and performing two-dimensional or three-dimensional mapping on the external environment.
  • the mobile platform includes at least one of an unmanned car, a remote control car, a robot, and a camera.
  • the platform body is the body of the automobile.
  • the car may be a self-driving car or a semi-automatic car, and no restriction is made here.
  • the platform body is the body of the remote control car.
  • the platform body is a robot.
  • the distance measuring device is applied to a camera, the platform body is the camera itself.
  • the disclosed device and method may be implemented in other ways.
  • the device embodiments described above are only schematic.
  • the division of the unit is only a logical function division, and in actual implementation, there may be another division manner, for example, multiple units or components may be combined or Can be integrated into another device, or some features can be ignored, or not implemented.
  • the various component embodiments of the present invention may be implemented in hardware, or implemented in software modules running on one or more processors, or implemented in a combination thereof.
  • a microprocessor or a digital signal processor (DSP) may be used to implement some or all functions of some modules according to embodiments of the present invention.
  • DSP digital signal processor
  • the present invention can also be implemented as a device program (for example, a computer program and a computer program product) for performing a part or all of the method described herein.
  • a program implementing the present invention may be stored on a computer-readable medium, or may have the form of one or more signals.
  • Such a signal can be downloaded from an Internet website, or provided on a carrier signal, or provided in any other form.

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Abstract

本发明提供一种激光测距装置及移动平台，所述激光测距装置包括发射模块，所述发射模块用于发射激光脉冲以探测待测物体，其中，所述激光脉冲为线偏振光，所述线偏振光的偏振方向平行于所述线偏振光的发射方向与干扰面的法向所构成的平面，所述干扰面包括水面或冰面。本发明的激光测距装置通过使出射光的偏振方向平行于反射平面，从而减少了水面或冰面产生的误测，提高了激光测距装置的可靠性。

Description

一种激光测距装置及移动平台
说明书
技术领域
本发明总地涉及测距装置技术领域，更具体地涉及一种激光测距装置及移动平台。
背景技术
例如激光雷达的激光测距装置在很多领域发挥着重要的作用，例如可以用于移动平台或非移动平台上，用来遥感、避障、测绘、建模等。以基于飞行时间(Time of flight,TOF)原理的激光雷达为例，激光雷达向外发射激光脉冲，接收外界物体反射产生的回波。通过测量回波的延时，能够计算出在该发射方向上物体与激光雷达的距离。通过动态的调整激光的出射方向，能够测量不同方位的物体与激光雷达的距离信息，从而实现对三维空间的建模。
当激光雷达发射的激光脉冲打到水面或冰面上时，会发生镜面反射，反射后的光线打到误探测物体上，产生的回波会在水面处再次发生镜面反射，最终被激光雷达接收，导致雷达产生误测。这种情况，在雨后的水面或者冰面上很容易发生，将会对激光雷达可靠性造成很大影响。
发明内容
为了解决上述问题中的至少一个而提出了本发明。具体地，本发明一方面提供一种激光测距装置，所述激光测距装置包括发射模块，所述发射模块用于发射激光脉冲以探测待测物体，其中，所述激光脉冲为线偏振光，所述线偏振光的偏振方向平行于所述线偏振光的发射方向与干扰面的法向所构成的平面，所述干扰面包括水面或冰面。
在一个实施例中，所述发射模块包括激光器，所述激光器用于发射所述线偏振光，所述激光器的摆放角度使得所述线偏振光的偏振方向平行于所述线偏振光的发射方向与所述干扰面的法向所构成的平面。
在一个实施例中，所述发射模块包括激光器和设置于所述激光器前方的半波片，其中，所述激光器用于发射线偏振光，所述线偏振光的偏振方向垂直于所述线偏振光的发射方向与所述干扰面的法向所构成的平面，所述半波 片用于将所述激光器发射的线偏振光的偏振方向旋转90°，以使得旋转后的线偏振光的偏振方向平行于所述线偏振光的发射方向与干扰面的法向所构成的平面。
在一个实施例中，所述发射模块包括激光器和设置于所述激光器前方的起偏器，所述激光器用于发射部分偏振光，所述起偏器使得所述部分偏振光透过所述起偏器之后成为所述线偏振光。
在一个实施例中，所述激光器包括半导体激光器。
在一个实施例中，所述激光测距装置还包括探测模块，用于接收所述待测物体反射的光束并转换为电信号，以及根据所述电信号确定所述待测物体与所述激光测距装置之间的距离。
在一个实施例中，所述激光测距装置包括激光雷达。
在一个实施例中，所述激光测距装置还包括：扫描模块；
所述发射模块用于向所述扫描模块发射激光脉冲序列，所述扫描模块用于改变所述激光脉冲序列的传输方向后出射，经待测物体反射回的激光脉冲序列经过所述扫描模块后入射至所述探测模块，所述探测模块用于根据反射回的激光脉冲序列确定所述待测物体相对所述激光测距装置的距离和/或方向。
本发明另一方面提供一种移动平台，所述移动平台包括：上述任一项所述的激光测距装置；以及，平台本体，所述激光测距装置安装在所述平台本体上。
在一个实施例中，所述移动平台包括汽车、遥控车或机器人中的至少一种。
本发明的激光测距装置通过使出射光的偏振方向平行于反射平面，从而减少了水面或冰面产生的误测，提高了激光测距装置的可靠性。
附图说明
为了更清楚地说明本发明实施例中的技术方案，下面将对实施例描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本发明的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动性的前提下，还可以根据这些附图获得其他的附图。
图1示出了水面或冰面导致激光测距装置误测的示意图；
图2示出了本发明第一实施例提供的激光测距装置的光路示意图；
图3示出了本发明实施例所提供的激光测距装置所发射的p波和对照组所发射的s波的反射率随入射角度变化曲线；
图4示出了本发明实施例所提供的激光测距装置所发射的p波和对照组所发射的s波的反射率随反射距离的变化曲线；
图5示出了本发明第二实施例提供的激光测距装置的光路示意图；
图6示出了本发明第三实施例提供的激光测距装置的光路示意图；
图7是本发明实施例提供的一种激光测距装置的示意性框架图；
图8是本发明实施例提供的激光测距装置采用同轴光路的一种实施例的示意图。
具体实施方式
为了使得本发明的目的、技术方案和优点更为明显，下面将参照附图详细描述根据本发明的示例实施例。显然，所描述的实施例仅仅是本发明的一部分实施例，而不是本发明的全部实施例，应理解，本发明不受这里描述的示例实施例的限制。基于本发明中描述的本发明实施例，本领域技术人员在没有付出创造性劳动的情况下所得到的所有其它实施例都应落入本发明的保护范围之内。
在下文的描述中，给出了大量具体的细节以便提供对本发明更为彻底的理解。然而，对于本领域技术人员而言显而易见的是，本发明可以无需一个或多个这些细节而得以实施。在其他的例子中，为了避免与本发明发生混淆，对于本领域公知的一些技术特征未进行描述。
应当理解的是，本发明能够以不同形式实施，而不应当解释为局限于这里提出的实施例。相反地，提供这些实施例将使公开彻底和完全，并且将本发明的范围完全地传递给本领域技术人员。
在此使用的术语的目的仅在于描述具体实施例并且不作为本发明的限制。在此使用时，单数形式的“一”、“一个”和“所述/该”也意图包括复数形式，除非上下文清楚指出另外的方式。还应明白术语“组成”和/或“包括”，当在该说明书中使用时，确定所述特征、整数、步骤、操作、元件和/或部件的存在，但不排除一个或更多其它的特征、整数、步骤、操作、元件、部件和/或组的存在或添加。在此使用时，术语“和/或”包括相关所列项目的任何及所有组合。
如图1所示，当激光测距装置101发射的激光脉冲102打到水面或冰面 103上时，会发生镜面反射，反射后的光线104打到误探测物体105上，产生的回波106会在水面或冰面103处再次发生镜面反射，产生的反射光107最终被激光测距装置101接收，导致激光测距装置101产生误测，即将误探测物体105的位置误测为误测位置108处，从而对激光测距装置101的可靠性造成很大影响。
为了解决上述问题，本发明提供了一种激光测距装置，所述激光测距装置包括发射模块，所述发射模块用于发射激光脉冲以探测待测物体，其中，所述激光脉冲为线偏振光，所述线偏振光的偏振方向平行于所述线偏振光的发射方向与干扰面的法向所构成的平面，所述干扰面包括水面或冰面。
本发明的激光测距装置通过使出射光的偏振方向平行于反射平面，从而减少了水面或冰面产生的误测，提高了激光测距装置的可靠性。
为了彻底理解本发明，将在下列的描述中提出详细的结构，以便阐释本发明提出的技术方案。本发明的可选实施例详细描述如下，然而除了这些详细描述外，本发明还可以具有其他实施方式。
下面结合附图，对本申请的激光测距装置进行详细说明。在不冲突的情况下，下述的实施例及实施方式中的特征可以相互组合。
作为示例，如图2、图5、图6所示，本发明的激光测距装置200包括发射模块210，用于发射激光脉冲序列。所述激光测距装置200可以是激光雷达，或者其他的适合的激光扫描装置。
其中，所述发射模块210所发射的激光脉冲203为线偏振光，即光矢量只沿着固定方向振动。所述线偏振光的偏振方向平行于所述线偏振光的发射方向与干扰面204的法向205所构成的平面，所述干扰面204包括水面或冰面，即所述干扰面通常为水平面。换句话说，所述发射模块210所发射的激光脉冲203为p波(即偏振方向平行于反射面，所述反射面指入射光线和反射光线所构成的平面)。
发射模块210可以包括激光器，其中，激光器可以是半导体激光器(或称为激光二极管)，例如可以是正极本征负极(positive-intrinsic-negative，PIN)光电二极管，该激光器可以发射特定波长的激光脉冲序列，该激光管可以称为光源或发射光源。
示例性地，所述发射模块210还包括开关器件和驱动器。开关器件为激光管的开关器件，可以与激光器连接，用于控制激光器的开关，其中，在激光器处于开的状态时，可以发射激光脉冲序列，在激光器处于关的状态时， 不发射激光脉冲序列。驱动器可以与开关器件连接，用于对开关器件进行驱动。
可选地，在本申请实施例中，该开关器件可以是金属氧化物半导体场效应管((metal-oxide-semiconductor，MOS)管，该驱动器可以包括MOS驱动器。其中，该MOS驱动器可以用于驱动作为开关元件的MOS管，MOS管可以控制激光管的开关。
可选地，该开关器件还可以为氮化镓(Gallium nitride，GaN)管，该驱动器可以为GaN驱动器。
本发明的第一实施例中，如图2所示，所述激光器201用于发射所述线偏振光。即，所述激光器201发射的激光脉冲203为线偏振光，并且，所述线偏振光的偏振方向平行于所述线偏振光的发射方向与干扰面204的法向所构成的平面。由于干扰面204通常为水平面，因而可以认为激光脉冲203的偏振方向与传播方向所构成的平面为竖直平面。示例性地，可调整所述激光器201的摆放角度，以使其发射的线偏振光的偏振方向平行于其发射方向与干扰面204的法向所构成的平面。
示例性地，所述激光器201包括上述的半导体激光器，所述半导体激光器的发光面为长方形，出射光为线偏振光，并且其偏振方向平行于长方形发光面的短边。在该示例中，将所述半导体激光器发光面的短边垂直于水平面摆放，此时的光路如图2所示。此时，入射到水面或冰面102的激光测距装置200的出射光的偏振方向平行于反射面(即出射光的发射方向与水面或冰面的法向所构成的平面)，换句话说，该出射光为p波。除此之外，所述激光器201也可以是任何合适的能够发射线偏振光的激光器，并且，其摆放角度使其发射的线偏振光为p波。
为了进行对照，将上述半导体激光器的发光面的短边平行于水平面摆放作为对照组，此时的出射光的偏振方向垂直于反射面，即该出射光为s波。
对于偏振方面平行于反射面的p波，其反射率表示为：
Figure PCTCN2018125452-appb-000001
对于偏振方向垂直于反射面的s波，其反射率表示为：
Figure PCTCN2018125452-appb-000002
其中i 1为入射角，i 2为折射角。
对于激光器的出射光入射到空气(折射率为1)与水(折射率为1.33)的界面的情况，p波(实线)和s波(虚线)的反射率随入射角度的变化如图3所示。从图3中可以看出，在入射角度较大时，反射率较大，但在任意入射角度下，p波的反射率均小于s波的反射率。
以激光测距装置摆放在高于水面1.5米的位置为例，p波和s波的反射率随反射距离变化的曲线如图4所示，其中所述反射距离为激光测距装置的出射光打到水面或冰面的位置与激光测距装置之间的水平距离。从图4可以看出，对于不同的反射距离来说，p波的反射率均小于s波，且反射距离小于10米时，下降效果尤为显著。也就是说，在本实施例中，通过选择合适的激光器摆放角度(如图2所示)，使出射光线的偏振方向平行于其出射方向与反射方向所构成的平面，从而使得入射到水面的激光测距装置的出射光线的反射率大大降低。
在本发明的第二实施例中，如图5所示，所述发射模块210包括激光器201和设置于所述激光器201前方的半波片206，其中，所述激光器201用于发射线偏振光，所述线偏振光的偏振方向垂直于所述线偏振光的发射方向与所述干扰面的法向所构成的平面，所述半波片206用于将所述激光器发射的线偏振光的偏振方向旋转90°，以使得旋转后的线偏振光的偏振方向平行于所述线偏振光的发射方向与干扰面的法向所构成的平面。
具体地，当由于其它原因导致激光器201的摆放角度不宜改变、且激光器201的出射光线的偏振方向垂直于反射面(即激光器的出射光为s波)时，可以在激光器201前方设置半波片206以改变其偏振方向。偏振光透过所述半波片206之后，其出射光仍为偏振光，并且偏振方向旋转了2θ角，其中θ角为入射光的偏振方向与偏振片光轴的夹角。
示例性地，所述激光器201可以是半导体激光器(或称为激光二极管)，例如可以是正极本征负极(positive-intrinsic-negative，PIN)光电二极管。所述半导体激光器的发光面为长方形，出射光为线偏振光，并且其偏振方向平行于长方形发光面的短边。由于外界因素的限制，例如受到激光测距装置整体结构的限制，半导体激光器发光面的短边平行于水平面摆放，其出射的激光脉冲为s波。通过调整半波片光轴的角度，可以使得激光器201发射的激光脉冲的偏振方向旋转90度。可以理解，当激光脉冲的偏振方向旋转90度之后，其偏振方向从垂直于反射面变为平行于反射面，即由s波变为p波。
在本发明的第三实施例中，如图6所示，所述发射模块210包括激光器201和设置于所述激光器201前方的起偏器207，所述激光器201用于发射部分偏振光，所述起偏器207使得所述部分偏振光透过所述起偏器207之后成为所述线偏振光。
对于出射光偏振度较小的激光器201，利用起偏器207使得入射到水面的光波为p波。其中，所述偏振度为在部分偏振光的总强度中，完全偏振光所占的比例。所述起偏器207可以是任何合适的用于从部分偏振光中获得线偏振光的器件，包括而不限于偏振片、尼科耳棱镜等。通过调整所述起偏器207的透振方向，可以使透过所述起偏器207的激光脉冲203的偏振方向平行于反射面。
本发明的上述实施例给出了几种使发射模块210的出射光为p波的结构，然而应理解，本发明不限于此，除上述结构之外，本发明实施例也可以采用其他能够使发射模块210的出射光为p波的结构。
在一个实施例中，所述激光测距装置200还包括扫描模块202，用于改变所述发射模块所发射的激光脉冲序列的传输方向后出射，以及将经待测物体反射回的激光脉冲序列入射至探测模块。其中，所述扫描模块仅改变所述激光脉冲的传输方向，而不改变所述激光脉冲的偏振方向。
在一个实施例中，扫描模块202可以包括至少一个光学元件，用于改变光束的传播路径，其中，该光学元件可以通过对光束进行反射、折射、衍射等等方式来改变光束传播路径。例如，扫描模块202包括透镜、反射镜、棱镜、振镜、光栅、液晶、光学相控阵(Optical Phased Array)或上述光学元件的任意组合。一个示例中，至少部分光学元件是运动的，例如通过驱动模块来驱动该至少部分光学元件进行运动，该运动的光学元件可以在不同时刻将光束反射、折射或衍射至不同的方向。在一些实施例中，扫描模块202的多个光学元件可以绕共同的轴旋转或振动，每个旋转或振动的光学元件用于不断改变入射光束的传播方向。在一个实施例中，扫描模块202的多个光学元件可以以不同的转速旋转，或以不同的速度振动。在另一个实施例中，扫描模块202的至少部分光学元件可以以基本相同的转速旋转。在一些实施例中，扫描模块的多个光学元件也可以是绕不同的轴旋转。在一些实施例中，扫描模块的多个光学元件也可以是以相同的方向旋转，或以不同的方向旋转；或者沿相同的方向振动，或者沿不同的方向振动，在此不作限制。
在一个示例中，激光测距装置200还包括准直透镜和会聚透镜，所述准 直透镜位于所述发射电路的发射光路上，用于将所述发射电路发射的激光脉冲序列准直后从所述测距装置出射，所述会聚透镜用于会聚物体反射的回光的至少一部分。准直透镜和会聚透镜可以是两个独立的凸透镜，或者，准直透镜和会聚透镜还可以为同一个透镜，例如同一个凸透镜。
在一个示例中，所述激光测距装置200还包括探测模块，用于接收经物体反射回的激光脉冲序列，以及根据所述反射回的激光脉冲序列确定所述物体相对所述测距装置的距离和/或方位。由于发射模块210发射的激光脉冲为p光，因而减小了干扰面的反射率，从而极大地降低了反射光导致探测模块产生误测的可能性。可选地，探测模块可以包括接收模块、采样模块和运算模块，接收模块用于将接收到的经所述物体反射回的激光脉冲序列转换为电信号输出；采样模块用于对所述接收模块输出的所述电信号进行采样，以测量所述激光脉冲序列从发射到接收之间的时间差；运算模块用于接收所述采样模块输出的所述时间差，计算获得距离测量结果。示例性地，可以将所述探测模块和所述发射模块210统称为测距模块。
在一个实施例中，激光测距装置200还包括控制模块，用于控制所述发射模块发射激光脉冲序列的频率。
综上所述，本发明实施例的激光测距装置通过使出射光的偏振方向平行于反射平面，从而减少了水面或冰面产生的误测，提高了激光测距装置的可靠性。
在另一个实施例中，本发明实施例还提供了一种移动平台，所述移动平台包括上述任一激光测距装置以及平台本体，所述激光测距装置安装在所述平台本体上。进一步地，所述移动平台包括汽车、机器人和遥控车中的至少一种。当测距装置应用于汽车时，平台本体为汽车的车身。该汽车可以是自动驾驶汽车或者半自动驾驶汽车，在此不做限制。当测距装置应用于遥控车时，平台本体为遥控车的车身。当测距装置应用于机器人时，平台本体为机器人。当测距装置应用于相机时，平台本体为相机本身。
本发明各个实施例提供的激光测距装置可以是激光雷达、激光测距设备等电子设备。在一种实施方式中，测距装置用于感测外部环境信息，例如，环境目标的距离信息、方位信息、反射强度信息、速度信息等。一种实现方式中，测距装置可以通过测量测距装置和待测物体之间光传播的时间，即光飞行时间(Time-of-Flight，TOF)，来探测待测物体到测距装置的距离。或者，测距装置也可以通过其他技术来探测待测物体到测距装置的距离，例如 基于相位移动(phase shift)测量的测距方法，或者基于频率移动(frequency shift)测量的测距方法，在此不做限制。
为了便于理解，以下将结合图7所示的激光测距装置700对测距的工作流程进行举例描述。
如图7所示，激光测距装置700可以包括发射电路710、接收电路720、采样电路730和运算电路740。
发射电路710可以发射激光脉冲序列(例如激光脉冲序列)。接收电路720可以接收经过待测物体反射的激光脉冲序列，并对该光脉冲序列进行光电转换，以得到电信号，再对电信号进行处理之后可以输出给采样电路730。采样电路730可以对电信号进行采样，以获取采样结果。运算电路740可以基于采样电路730的采样结果，以确定激光测距装置700与待测物体之间的距离。
可选地，该激光测距装置700还可以包括控制电路750，该控制电路750可以实现对其他电路的控制，例如，可以控制各个电路的工作时间和/或对各个电路进行参数设置等。
应理解，虽然图7示出的激光测距装置中包括一个发射电路、一个接收电路、一个采样电路和一个运算电路，用于出射一路光束进行探测，但是本申请实施例并不限于此，发射电路、接收电路、采样电路、运算电路中的任一种电路的数量也可以是至少两个，用于沿相同方向或分别沿不同方向出射至少两路光束；其中，该至少两束光路可以是同时出射，也可以是分别在不同时刻出射。一个示例中，该至少两个发射电路中的发光芯片封装在同一个模块中。例如，每个发射电路包括一个激光发射芯片，该至少两个发射电路中的激光发射芯片中的die封装到一起，容置在同一个封装空间中。
一些实现方式中，除了图7所示的电路，激光测距装置700还可以包括扫描模块，用于将发射电路出射的至少一路激光脉冲序列改变传播方向出射。
其中，可以将包括发射电路710、接收电路720、采样电路730和运算电路740的模块，或者，包括发射电路710、接收电路720、采样电路730、运算电路740和控制电路750的模块称为测距模块，该测距模块750可以独立于其他模块，例如，扫描模块。
测距装置中可以采用同轴光路，也即测距装置出射的光束和经反射回来的光束在测距装置内共用至少部分光路。例如，发射电路出射的至少一路激光脉冲序列经扫描模块改变传播方向出射后，经待测物体反射回来的激光脉 冲序列经过扫描模块后入射至接收电路。或者，测距装置也可以采用异轴光路，也即测距装置出射的光束和经反射回来的光束在测距装置内分别沿不同的光路传输。图8示出了本发明的激光测距装置采用同轴光路的一种实施例的示意图。
激光测距装置800包括测距模块801，测距模块801包括发射器803(可以包括上述的发射电路)、准直元件804、探测器805(可以包括上述的接收电路、采样电路和运算电路)和光路改变元件806。测距模块801用于发射光束，且接收回光，将回光转换为电信号。其中，发射器803可以用于发射激光脉冲序列。在一个实施例中，发射器803可以发射激光脉冲序列。可选的，发射器803发射出的激光束为波长在可见光范围之外的窄带宽光束。准直元件804设置于发射器的出射光路上，用于准直从发射器803发出的光束，将发射器803发出的光束准直为平行光出射至扫描模块。准直元件还用于会聚经待测物体反射的回光的至少一部分。该准直元件804可以是准直透镜或者是其他能够准直光束的元件。
在图8所示实施例中，通过光路改变元件806来将测距装置内的发射光路和接收光路在准直元件804之前合并，使得发射光路和接收光路可以共用同一个准直元件，使得光路更加紧凑。在其他的一些实现方式中，也可以是发射器803和探测器805分别使用各自的准直元件，将光路改变元件806设置在准直元件之后的光路上。
在图8所示实施例中，由于发射器803出射的光束的光束孔径较小，测距装置所接收到的回光的光束孔径较大，所以光路改变元件可以采用小面积的反射镜来将发射光路和接收光路合并。在其他的一些实现方式中，光路改变元件也可以采用带通孔的反射镜，其中该通孔用于透射发射器803的出射光，反射镜用于将回光反射至探测器805。这样可以减小采用小反射镜的情况中小反射镜的支架会对回光的遮挡。
在图8所示实施例中，光路改变元件偏离了准直元件804的光轴。在其他的一些实现方式中，光路改变元件也可以位于准直元件804的光轴上。
激光测距装置800还包括扫描模块802。扫描模块802放置于测距模块801的出射光路上，扫描模块802用于改变经准直元件804出射的准直光束819的传输方向并投射至外界环境，并将回光投射至准直元件804。回光经准直元件804汇聚到探测器805上。
在一个实施例中，扫描模块802可以包括至少一个光学元件，用于改变 光束的传播路径，其中，该光学元件可以通过对光束进行反射、折射、衍射等等方式来改变光束传播路径。例如，扫描模块802包括透镜、反射镜、棱镜、振镜、光栅、液晶、光学相控阵(Optical Phased Array)或上述光学元件的任意组合。一个示例中，至少部分光学元件是运动的，例如通过驱动模块来驱动该至少部分光学元件进行运动，该运动的光学元件可以在不同时刻将光束反射、折射或衍射至不同的方向。在一些实施例中，扫描模块802的多个光学元件可以绕共同的转动轴809旋转或振动，每个旋转或振动的光学元件用于不断改变入射光束的传播方向。在一个实施例中，扫描模块802的多个光学元件可以以不同的转速旋转，或以不同的速度振动。在另一个实施例中，扫描模块802的至少部分光学元件可以以基本相同的转速旋转。在一些实施例中，扫描模块的多个光学元件也可以是绕不同的轴旋转。在一些实施例中，扫描模块的多个光学元件也可以是以相同的方向旋转，或以不同的方向旋转；或者沿相同的方向振动，或者沿不同的方向振动，在此不作限制。
在一个实施例中，扫描模块802包括第一光学元件814和与第一光学元件814连接的驱动器816，驱动器816用于驱动第一光学元件814绕转动轴809转动，使第一光学元件814改变准直光束819的方向。第一光学元件814将准直光束819投射至不同的方向。在一个实施例中，准直光束819经第一光学元件改变后的方向与转动轴809的夹角随着第一光学元件814的转动而变化。在一个实施例中，第一光学元件814包括相对的非平行的一对表面，准直光束819穿过该对表面。在一个实施例中，第一光学元件814包括厚度沿至少一个径向变化的棱镜。在一个实施例中，第一光学元件814包括楔角棱镜，对准直光束819进行折射。
在一个实施例中，扫描模块802还包括第二光学元件815，第二光学元件815绕转动轴809转动，第二光学元件815的转动速度与第一光学元件814的转动速度不同。第二光学元件815用于改变第一光学元件814投射的光束的方向。在一个实施例中，第二光学元件815与另一驱动器817连接，驱动器817驱动第二光学元件815转动。第一光学元件814和第二光学元件815可以由相同或不同的驱动器驱动，使第一光学元件814和第二光学元件815的转速和/或转向不同，从而将准直光束819投射至外界空间不同的方向，可以扫描较大的空间范围。在一个实施例中，控制器818控制驱动器816和817，分别驱动第一光学元件814和第二光学元件815。第一光学元件814和第二光学元件815的转速可以根据实际应用中预期扫描的区域和样式确定。驱动 器816和817可以包括电机或其他驱动器。
在一个实施例中，第二光学元件815包括相对的非平行的一对表面，光束穿过该对表面。在一个实施例中，第二光学元件815包括厚度沿至少一个径向变化的棱镜。在一个实施例中，第二光学元件815包括楔角棱镜。
一个实施例中，扫描模块802还包括第三光学元件(图未示)和用于驱动第三光学元件运动的驱动器。可选地，该第三光学元件包括相对的非平行的一对表面，光束穿过该对表面。在一个实施例中，第三光学元件包括厚度沿至少一个径向变化的棱镜。在一个实施例中，第三光学元件包括楔角棱镜。第一、第二和第三光学元件中的至少两个光学元件以不同的转速和/或转向转动。
扫描模块802中的各光学元件旋转可以将光投射至不同的方向，例如方向811和813，如此对激光测距装置800周围的空间进行扫描。当扫描模块802投射出的光811打到待测物体810时，一部分光被待测物体810沿与投射的光811相反的方向反射至激光测距装置800。待测物体810反射的回光812经过扫描模块802后入射至准直元件804。
探测器805与发射器803放置于准直元件804的同一侧，探测器805用于将穿过准直元件804的至少部分回光转换为电信号。
一个实施例中，各光学元件上镀有增透膜。可选的，增透膜的厚度与发射器803发射出的光束的波长相等或接近，能够增加透射光束的强度。
一个实施例中，测距装置中位于光束传播路径上的一个元件表面上镀有滤光层，或者在光束传播路径上设置有滤光器，用于至少透射发射器所出射的光束所在波段，反射其他波段，以减少环境光给接收器带来的噪音。
在一些实施例中，发射器803可以包括激光二极管，通过激光二极管发射纳秒级别的激光脉冲。进一步地，可以确定激光脉冲接收时间，例如，通过探测电信号脉冲的上升沿时间和/或下降沿时间确定激光脉冲接收时间。如此，激光测距装置800可以利用脉冲接收时间信息和脉冲发出时间信息计算TOF，从而确定待测物体810到激光测距装置800的距离。
激光测距装置800探测到的距离和方位可以用于遥感、避障、测绘、建模、导航等。在一种实施方式中，本发明实施方式的测距装置可应用于移动平台，测距装置可安装在移动平台的平台本体。具有测距装置的移动平台可对外部环境进行测量，例如，测量移动平台与障碍物的距离用于避障等用途，和对外部环境进行二维或三维的测绘。在某些实施方式中，移动平台包括无 人汽车、遥控车、机器人、相机中的至少一种。当测距装置应用于汽车时，平台本体为汽车的车身。该汽车可以是自动驾驶汽车或者半自动驾驶汽车，在此不做限制。当测距装置应用于遥控车时，平台本体为遥控车的车身。当测距装置应用于机器人时，平台本体为机器人。当测距装置应用于相机时，平台本体为相机本身。
尽管这里已经参考附图描述了示例实施例，应理解上述示例实施例仅仅是示例性的，并且不意图将本发明的范围限制于此。本领域普通技术人员可以在其中进行各种改变和修改，而不偏离本发明的范围和精神。所有这些改变和修改意在被包括在所附权利要求所要求的本发明的范围之内。
本领域普通技术人员可以意识到，结合本文中所公开的实施例描述的各示例的单元及算法步骤，能够以电子硬件、或者计算机软件和电子硬件的结合来实现。这些功能究竟以硬件还是软件方式来执行，取决于技术方案的特定应用和设计约束条件。专业技术人员可以对每个特定的应用来使用不同方法来实现所描述的功能，但是这种实现不应认为超出本发明的范围。
在本申请所提供的几个实施例中，应该理解到，所揭露的设备和方法，可以通过其它的方式实现。例如，以上所描述的设备实施例仅仅是示意性的，例如，所述单元的划分，仅仅为一种逻辑功能划分，实际实现时可以有另外的划分方式，例如多个单元或组件可以结合或者可以集成到另一个设备，或一些特征可以忽略，或不执行。
在此处所提供的说明书中，说明了大量具体细节。然而，能够理解，本发明的实施例可以在没有这些具体细节的情况下实践。在一些实例中，并未详细示出公知的方法、结构和技术，以便不模糊对本说明书的理解。
类似地，应当理解，为了精简本发明并帮助理解各个发明方面中的一个或多个，在对本发明的示例性实施例的描述中，本发明的各个特征有时被一起分组到单个实施例、图、或者对其的描述中。然而，并不应将该本发明的方法解释成反映如下意图：即所要求保护的本发明要求比在每个权利要求中所明确记载的特征更多的特征。更确切地说，如相应的权利要求书所反映的那样，其发明点在于可以用少于某个公开的单个实施例的所有特征的特征来解决相应的技术问题。因此，遵循具体实施方式的权利要求书由此明确地并入该具体实施方式，其中每个权利要求本身都作为本发明的单独实施例。
本领域的技术人员可以理解，除了特征之间相互排斥之外，可以采用任何组合对本说明书(包括伴随的权利要求、摘要和附图)中公开的所有特征 以及如此公开的任何方法或者设备的所有过程或单元进行组合。除非另外明确陈述，本说明书(包括伴随的权利要求、摘要和附图)中公开的每个特征可以由提供相同、等同或相似目的替代特征来代替。
此外，本领域的技术人员能够理解，尽管在此所述的一些实施例包括其它实施例中所包括的某些特征而不是其它特征，但是不同实施例的特征的组合意味着处于本发明的范围之内并且形成不同的实施例。例如，在权利要求书中，所要求保护的实施例的任意之一都可以以任意的组合方式来使用。
本发明的各个部件实施例可以以硬件实现，或者以在一个或者多个处理器上运行的软件模块实现，或者以它们的组合实现。本领域的技术人员应当理解，可以在实践中使用微处理器或者数字信号处理器(DSP)来实现根据本发明实施例的一些模块的一些或者全部功能。本发明还可以实现为用于执行这里所描述的方法的一部分或者全部的装置程序(例如，计算机程序和计算机程序产品)。这样的实现本发明的程序可以存储在计算机可读介质上，或者可以具有一个或者多个信号的形式。这样的信号可以从因特网网站上下载得到，或者在载体信号上提供，或者以任何其他形式提供。
应该注意的是上述实施例对本发明进行说明而不是对本发明进行限制，并且本领域技术人员在不脱离所附权利要求的范围的情况下可设计出替换实施例。在权利要求中，不应将位于括号之间的任何参考符号构造成对权利要求的限制。本发明可以借助于包括有若干不同元件的硬件以及借助于适当编程的计算机来实现。在列举了若干装置的单元权利要求中，这些装置中的若干个可以是通过同一个硬件项来具体体现。单词第一、第二、以及第三等的使用不表示任何顺序。可将这些单词解释为名称。

Claims (10)

  1. 一种激光测距装置，其特征在于，所述激光测距装置包括发射模块，所述发射模块用于发射激光脉冲以探测待测物体，其中，所述激光脉冲为线偏振光，所述线偏振光的偏振方向平行于所述线偏振光的发射方向与干扰面的法向所构成的平面，所述干扰面包括水面或冰面。
  2. 如权利要求1所述的激光测距装置，其特征在于，所述发射模块包括激光器，所述激光器用于发射所述线偏振光，所述激光器的摆放角度使得所述线偏振光的偏振方向平行于所述线偏振光的发射方向与所述干扰面的法向所构成的平面。
  3. 如权利要求1所述的激光测距装置，其特征在于，所述发射模块包括激光器和设置于所述激光器前方的半波片，其中，所述激光器用于发射线偏振光，所述线偏振光的偏振方向垂直于所述线偏振光的发射方向与所述干扰面的法向所构成的平面，所述半波片用于将所述激光器发射的线偏振光的偏振方向旋转90°，以使得旋转后的线偏振光的偏振方向平行于所述线偏振光的发射方向与干扰面的法向所构成的平面。
  4. 如权利要求1所述的激光测距装置，其特征在于，所述发射模块包括激光器和设置于所述激光器前方的起偏器，所述激光器用于发射部分偏振光，所述起偏器使得所述部分偏振光透过所述起偏器之后成为所述线偏振光。
  5. 如权利要求2至4中任一项所述的激光测距装置，其特征在于，所述激光器包括半导体激光器。
  6. 如权利要求1所述的激光测距装置，其特征在于，所述激光测距装置还包括探测模块，用于接收所述待测物体反射的光束并转换为电信号，以及根据所述电信号确定所述待测物体与所述激光测距装置之间的距离。
  7. 如权利要求1所述的激光测距装置，其特征在于，所述激光测距装置包括激光雷达。
  8. 如权利要求6所述的激光测距装置，其特征在于，还包括：
    扫描模块；
    所述发射模块用于向所述扫描模块发射激光脉冲序列，所述扫描模块用于改变所述激光脉冲序列的传输方向后出射，经待测物体反射回的激光脉冲序列经过所述扫描模块后入射至所述探测模块，所述探测模块用于根据反射回的激光脉冲序列确定所述待测物体相对所述激光测距装置的距离和/或方向。
  9. 一种移动平台，其特征在于，包括：
    权利要求1至8中任一项所述的激光测距装置；以及
    平台本体，所述激光测距装置安装在所述平台本体上。
  10. 如权利要求9所述的移动平台，其特征在于，所述移动平台包括汽车、遥控车或机器人中的至少一种。
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