CN111712734A - Laser ranging device and mobile platform - Google Patents
Laser ranging device and mobile platform Download PDFInfo
- Publication number
- CN111712734A CN111712734A CN201880069663.5A CN201880069663A CN111712734A CN 111712734 A CN111712734 A CN 111712734A CN 201880069663 A CN201880069663 A CN 201880069663A CN 111712734 A CN111712734 A CN 111712734A
- Authority
- CN
- China
- Prior art keywords
- laser
- polarized light
- linearly polarized
- ranging device
- module
- Prior art date
- Legal status (The legal status 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 status listed.)
- Pending
Links
- 230000010287 polarization Effects 0.000 claims abstract description 42
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 22
- 238000001208 nuclear magnetic resonance pulse sequence Methods 0.000 claims description 29
- 239000004065 semiconductor Substances 0.000 claims description 10
- 230000005540 biological transmission Effects 0.000 claims description 9
- 238000001514 detection method Methods 0.000 claims description 9
- 238000005259 measurement Methods 0.000 abstract description 8
- 230000003287 optical effect Effects 0.000 description 86
- 238000005070 sampling Methods 0.000 description 15
- 238000001615 p wave Methods 0.000 description 14
- 238000000034 method Methods 0.000 description 11
- 238000010586 diagram Methods 0.000 description 7
- 238000002310 reflectometry Methods 0.000 description 7
- 230000008859 change Effects 0.000 description 6
- JMASRVWKEDWRBT-UHFFFAOYSA-N Gallium nitride Chemical compound [Ga]#N JMASRVWKEDWRBT-UHFFFAOYSA-N 0.000 description 2
- 238000004590 computer program Methods 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 239000004973 liquid crystal related substance Substances 0.000 description 2
- 238000013507 mapping Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000010363 phase shift Effects 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 229910002601 GaN Inorganic materials 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000002592 echocardiography Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005669 field effect Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000004806 packaging method and process Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
Images
Classifications
-
- 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
Abstract
The invention provides a laser ranging device and a mobile platform, wherein the laser ranging device comprises an emission module, the emission module is used for emitting laser pulses to detect an object to be measured, the laser pulses are linearly polarized light, the polarization direction of the linearly polarized light is parallel to a plane formed by the emission direction of the linearly polarized light and the normal direction of an interference surface, and the interference surface comprises a water surface or an ice surface. The laser ranging device of the invention reduces the error measurement generated on the water surface or the ice surface and improves the reliability of the laser ranging device by enabling the polarization direction of the emergent light to be parallel to the reflection plane.
Description
Description
The present invention generally relates to the field of distance measuring devices, and more particularly to a laser distance measuring device and a mobile platform.
Laser ranging devices, such as lidar, play an important role in many fields, such as being used on mobile or non-mobile platforms for remote sensing, obstacle avoidance, mapping, modeling, and the like. Taking a laser radar based on the Time of flight (TOF) principle as an example, the laser radar emits laser pulses outwards and receives echoes generated by the reflection of external objects. By measuring the time delay of the echo, the distance between the object and the laser radar in the transmitting direction can be calculated. By dynamically adjusting the emitting direction of the laser, the distance information between objects in different directions and the laser radar can be measured, and therefore modeling of a three-dimensional space is achieved.
When laser pulse of laser radar transmission hits the surface of water or on the ice surface, can take place specular reflection, on the misdetection object was hit to light after the reflection, the echo of production can take place specular reflection again in surface of water department, finally is received by laser radar, leads to the radar to produce the misdetection. This situation is likely to occur on a water surface or an ice surface after rain, and will have a great influence on the reliability of the laser radar.
Disclosure of Invention
The present invention has been made to solve at least one of the above problems. The laser ranging device comprises a transmitting module, wherein the transmitting module is used for transmitting laser pulses to detect an object to be measured, the laser pulses are linearly polarized light, the polarization direction of the linearly polarized light is parallel to a plane formed by the transmitting direction of the linearly polarized light and the normal direction of an interference surface, and the interference surface comprises a water surface or an ice surface.
In one embodiment, the emitting module includes a laser, the laser is used for emitting the linearly polarized light, and the placing angle of the laser makes the polarization direction of the linearly polarized light parallel to a plane formed by the emitting direction of the linearly polarized light and the normal direction of the interference surface.
In one embodiment, the transmitting module comprises a laser and a half-wave plate arranged in front of the laser, wherein the laser is used for transmitting linearly polarized light, the polarization direction of the linearly polarized light is perpendicular to a plane formed by the transmitting direction of the linearly polarized light and the normal direction of the interference surface, and the half-wave plate is used for rotating the polarization direction of the linearly polarized light transmitted by the laser by 90 degrees, so that the polarization direction of the linearly polarized light after rotation is parallel to the plane formed by the transmitting direction of the linearly polarized light and the normal direction of the interference surface.
In one embodiment, the transmitting module comprises a laser and a polarizer arranged in front of the laser, the laser is used for transmitting partial polarized light, and the polarizer enables the partial polarized light to become the linearly polarized light after the partial polarized light is transmitted through the polarizer.
In one embodiment, the laser comprises a semiconductor laser.
In one embodiment, the laser ranging device further includes a detection module, configured to receive the light beam reflected by the object to be measured and convert the light beam into an electrical signal, and determine a distance between the object to be measured and the laser ranging device according to the electrical signal.
In one embodiment, the laser ranging device comprises a lidar.
In one embodiment, the laser ranging apparatus further comprises: a scanning module;
the transmitting module is used for transmitting a laser pulse sequence to the scanning module, the scanning module is used for changing the transmission direction of the laser pulse sequence and then emitting the laser pulse sequence, the laser pulse sequence reflected back by the object to be detected enters the detecting module after passing through the scanning module, and the detecting module is used for determining the distance and/or the direction of the object to be detected relative to the laser ranging device according to the reflected laser pulse sequence.
Another aspect of the present invention provides a mobile platform, including: the laser ranging device of any one of the above; and the laser ranging device is arranged on the platform body.
In one embodiment, the mobile platform comprises at least one of an automobile, a remote control car, or a robot.
The laser ranging device of the invention reduces the error measurement generated on the water surface or the ice surface and improves the reliability of the laser ranging device by enabling the polarization direction of the emergent light to be parallel to the reflection plane.
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive labor.
FIG. 1 shows a schematic diagram of a water or ice surface causing a laser ranging device to misdetect;
fig. 2 is a schematic optical path diagram of a laser distance measuring device according to a first embodiment of the present invention;
FIG. 3 is a graph showing the reflection rate of p-waves emitted by a laser ranging device and s-waves emitted by a control group according to the incident angle;
FIG. 4 is a graph showing the reflection rate of p-waves emitted from a laser ranging device and s-waves emitted from a control group according to the embodiment of the present invention;
fig. 5 is a schematic optical path diagram of a laser distance measuring device according to a second embodiment of the present invention;
fig. 6 is a schematic optical path diagram of a laser distance measuring device according to a third embodiment of the present invention;
FIG. 7 is a schematic block diagram of a laser ranging device according to an embodiment of the present invention;
fig. 8 is a schematic diagram of an embodiment of a laser distance measuring device using a coaxial optical path according to an embodiment of the present invention.
In order to make the objects, technical solutions and advantages of the present invention more apparent, exemplary embodiments according to the present invention will be described in detail below with reference to the accompanying drawings. It is to be understood that the described embodiments are merely a subset of embodiments of the invention and not all embodiments of the invention, with the understanding that the invention is not limited to the example embodiments described herein. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the invention described herein without inventive step, shall fall within the scope of protection of the invention.
In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the present invention. It will be apparent, however, to one skilled in the art, that the present invention may be practiced without one or more of these specific details. In other instances, well-known features have not been described in order to avoid obscuring the invention.
It is to be understood that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. As used herein, the term "and/or" includes any and all combinations of the associated listed items.
As shown in fig. 1, when a laser pulse 102 emitted by a laser ranging device 101 hits a water surface or an ice surface 103, a specular reflection occurs, a reflected light 104 hits an object 105 to be detected by mistake, a generated echo 106 is specularly reflected again at the water surface or the ice surface 103, and a generated reflected light 107 is finally received by the laser ranging device 101, so that the laser ranging device 101 generates a false detection, that is, the position of the object 105 to be detected by mistake is detected as a false detection position 108, thereby greatly affecting the reliability of the laser ranging device 101.
In order to solve the problems, the invention provides a laser ranging device which comprises an emitting module, wherein the emitting module is used for emitting laser pulses to detect an object to be measured, the laser pulses are linearly polarized light, the polarization direction of the linearly polarized light is parallel to a plane formed by the emitting direction of the linearly polarized light and the normal direction of an interference surface, and the interference surface comprises a water surface or an ice surface.
The laser ranging device of the invention reduces the error measurement generated on the water surface or the ice surface and improves the reliability of the laser ranging device by enabling the polarization direction of the emergent light to be parallel to the reflection plane.
In order to provide a thorough understanding of the present invention, a detailed structure will be set forth in the following description in order to explain the present invention. Alternative embodiments of the invention are described in detail below, however, the invention may be practiced in other embodiments that depart from these specific details.
The laser ranging apparatus of the present application will be described in detail below with reference to the accompanying drawings. The features of the following examples and embodiments may be combined with each other without conflict.
As an example, as shown in fig. 2, 5 and 6, the laser ranging apparatus 200 of the present invention includes a transmitting module 210 for transmitting a laser pulse sequence. The laser ranging device 200 may be a lidar, 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 vibrates only along a fixed direction. The polarization direction of the linearly polarized light is parallel to a plane formed by the emission direction of the linearly polarized light and a normal 205 of the interference surface 204, and the interference surface 204 comprises a water surface or an ice surface, i.e. the interference surface is generally a horizontal plane. In other words, the laser pulse 203 emitted by the emitting module 210 is p-wave (i.e. the polarization direction is parallel to the reflection surface, which is the plane formed by the incident light and the reflected light).
The emitting module 210 may include a laser, wherein the laser may be a semiconductor laser (or referred to as a laser diode), such as a positive-intrinsic-negative (PIN) photodiode, and the laser may emit a laser pulse sequence with a specific wavelength, and the laser tube may be referred to as a light source or an emitting light source.
Illustratively, the transmitting module 210 further includes a switching device and a driver. The switching device is a switching device of a laser tube, can be connected with the laser and is used for controlling the switching of the laser, wherein when the laser is in an on state, the laser pulse sequence can be emitted, and when the laser is in an off state, the laser pulse sequence is not emitted. The driver may be connected to the switching device for driving the switching device.
Alternatively, in the embodiment of the present application, the switching device may be a metal-oxide-semiconductor field-effect transistor (MOS) transistor, and the driver may include a MOS driver.
Alternatively, the switching device may be a Gallium nitride (GaN) transistor, and the driver may be a GaN driver.
In the first embodiment of the present invention, as shown in fig. 2, 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 plane 204 is generally a horizontal plane, the plane formed by the polarization direction and the propagation direction of the laser pulse 203 can be considered to be a vertical plane. Illustratively, the angle of the laser 201 can be adjusted so that the polarization direction of the linearly polarized light emitted by the laser is parallel to the plane formed by the emission direction and the normal direction of the interference surface 204.
Illustratively, the laser 201 includes the above-mentioned semiconductor laser, the light emitting surface of which is rectangular, the outgoing light is linearly polarized light, and the polarization direction of which is parallel to the short side of the rectangular light emitting surface. In this example, the short side of the light emitting surface of the semiconductor laser is placed perpendicular to the horizontal plane, and the optical path is as shown in fig. 2. At this time, the polarization direction of the outgoing light from the laser range finder 200 incident on the water surface or ice surface 102 is parallel to the reflection surface (i.e., a plane formed by the emission direction of the outgoing light and the normal direction of the water surface or ice surface), in other words, the outgoing light is a p-wave. In addition, the laser 201 may be any suitable laser capable of emitting linearly polarized light, and the angle of the laser is set such that the emitted linearly polarized light is p-wave.
For comparison, the short side of the light emitting surface of the semiconductor laser is placed parallel to the horizontal plane as a comparison group, and the polarization direction of the outgoing light at this time is perpendicular to the reflection surface, that is, the outgoing light is s-wave.
For a p-wave with polarization parallel to the reflecting surface, the reflectivity is expressed as:
for s-waves with polarization direction perpendicular to the reflecting surface, the reflectivity is expressed as:
wherein i1Is an angle of incidence, i2Is the angle of refraction.
In the case where the outgoing light from the laser enters the interface between air (refractive index of 1) and water (refractive index of 1.33), the reflectance of the p-wave (solid line) and s-wave (broken line) varies with the incident angle as shown in fig. 3. As can be seen from fig. 3, the reflectivity is larger at larger incidence angles, but the reflectivity of the p-wave is smaller than the reflectivity of the s-wave at any incidence angle.
Taking the laser distance measuring device placed at a position 1.5 meters above the water surface as an example, the curve of the reflection rate of the p-wave and the s-wave changing along with the reflection distance is shown in fig. 4, wherein the reflection distance is the horizontal distance between the position of the emergent light of the laser distance measuring device hitting the water surface or the ice surface and the laser distance measuring device. As can be seen from fig. 4, for different reflection distances, the reflection rate of the p-wave is smaller than that of the s-wave, and the reduction effect is particularly significant when the reflection distance is smaller than 10 meters. That is, in this embodiment, by selecting a suitable laser placement angle (as shown in fig. 2), the polarization direction of the outgoing light is made parallel to the plane formed by the outgoing direction and the reflection direction, so that the reflectivity of the outgoing light entering the laser ranging device on the water surface is greatly reduced.
In a second embodiment of the present invention, as shown in fig. 5, 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 configured to emit linearly polarized light, a polarization direction of the linearly polarized light is perpendicular to a plane formed by the emission direction of the linearly polarized light and a normal direction of the interference surface, and the half-wave plate 206 is configured to rotate the polarization direction of the linearly polarized light emitted by the laser by 90 ° so that the polarization direction of the linearly polarized light after rotation is parallel to a plane formed by the emission direction of the linearly polarized light and the normal direction of the interference surface.
Specifically, when the angle of the laser 201 is not easy to change due to other reasons and the polarization direction of the outgoing light of the laser 201 is perpendicular to the reflection surface (i.e., the outgoing light of the laser is s-wave), a half-wave plate 206 may be disposed in front of the laser 201 to change the polarization direction thereof. After the polarized light passes through the half-wave plate 206, the emergent light is still polarized, and the polarization direction is rotated by an angle 2 θ, where the angle θ is the angle between the polarization direction of the incident light and the optical axis of the polarizer.
Illustratively, the laser 201 may be a semiconductor laser (or referred to as a laser diode), such as a positive-intrinsic-negative (PIN) photodiode. The light emitting surface of the semiconductor laser is rectangular, emergent light is linearly polarized light, and the polarization direction of the emergent light is parallel to the short edge of the rectangular light emitting surface. Due to the limitation of external factors, such as the limitation of the overall structure of the laser distance measuring device, the short side of the light emitting surface of the semiconductor laser is arranged parallel to the horizontal plane, and the emitted laser pulse is s-wave. By adjusting the angle of the optical axis of the half-wave plate, the polarization direction of the laser pulses emitted by the laser 201 can be rotated by 90 degrees. It is understood that when 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, i.e., from s-wave to p-wave.
In a third embodiment of the present invention, as shown in fig. 6, the transmitting module 210 includes a laser 201 and a polarizer 207 disposed in front of the laser 201, the laser 201 is configured to transmit partially polarized light, and the polarizer 207 makes the partially polarized light become the linearly polarized light after transmitting through the polarizer 207.
For the laser 201 with a small degree of polarization of the outgoing light, the light wave incident on the water surface is made to be a p-wave by the polarizer 207. The polarization degree is the proportion of the completely polarized light in the total intensity of the partially polarized light. The polarizer 207 may be any suitable device for obtaining linearly polarized light from partially polarized light, including without limitation a polarizer, a nicols, and the like. By adjusting the transmission direction of the polarizer 207, the polarization direction of the laser pulse 203 transmitted through the polarizer 207 can be made parallel to the reflection surface.
The above embodiments of the present invention have shown several structures for making the outgoing light of the emitting module 210 be p-wave, however, it should be understood that the present invention is not limited thereto, and besides the above structures, other structures capable of making the outgoing light of the emitting module 210 be p-wave may also be adopted in the embodiments of the present invention.
In one embodiment, the laser ranging apparatus 200 further includes a scanning module 202, configured to change a transmission direction of the laser pulse sequence emitted by the emitting module and emit the laser pulse sequence, and to emit the laser pulse sequence reflected by the object to be detected into the detecting module. Wherein the scanning module only changes the transmission direction of the laser pulses without changing the polarization direction of the laser pulses.
In one embodiment, the scanning module 202 may include at least one optical element for altering the propagation path of the light beam, wherein the optical element may alter the propagation path of the light beam by reflecting, refracting, diffracting, etc., the light beam. For example, the scanning module 202 includes a lens, mirror, prism, galvanometer, grating, liquid crystal, Optical Phased Array (Optical Phased Array), or any combination thereof. In one example, at least a portion of the optical element is moved, for example, by a driving module, and the moved optical element can reflect, refract, or diffract the light beam to different directions at different times. In some embodiments, multiple optical elements of the scanning module 202 may rotate or oscillate about a common axis, with each rotating or oscillating optical element serving to constantly change the direction of propagation of an incident beam. In one embodiment, the multiple optical elements of the scanning module 202 may rotate at different rotational speeds or oscillate at different speeds. In another embodiment, at least some of the optical elements of the scanning module 202 may rotate at substantially the same rotational speed. In some embodiments, the multiple optical elements of the scanning module may also be rotated about different axes. In some embodiments, the multiple optical elements of the scanning module may also rotate in the same direction, or in different directions; or in the same direction, or in different directions, without limitation.
In one example, the laser distance measuring 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 for collimating the laser pulse sequence emitted by the emitting circuit and then emitting the laser pulse sequence from the distance measuring device, and the converging lens is used for converging at least a part of the return light reflected by the object. The collimating lens and the converging lens may be two separate convex lenses, or the collimating lens and the converging lens may also be the same lens, e.g. the same convex lens.
In one example, the laser ranging device 200 further comprises a detection module for receiving the laser pulse sequence reflected back by the object and determining the distance and/or orientation of the object relative to the ranging device from the reflected laser pulse sequence. Since the laser pulse emitted by the emitting module 210 is p-light, the reflectivity of the interference surface is reduced, and the possibility of false detection caused by the reflected light of the detection module is greatly reduced. Optionally, the detection module may include a receiving module, a sampling module, and an operation module, where the receiving module is configured to convert the received laser pulse sequence reflected back by the object into an electrical signal and output the electrical signal; the sampling module is used for sampling the electric signal output by the receiving module so as to measure the time difference between the emission and the reception of the laser pulse sequence; and the operation module is used for receiving the time difference output by the sampling module and calculating to obtain a distance measurement result. Illustratively, the detection module and the transmission module 210 may be collectively referred to as a ranging module.
In one embodiment, the laser ranging device 200 further comprises a control module for controlling the frequency at which the transmission module transmits the laser pulse sequence.
In summary, the laser ranging device according to the embodiment of the invention reduces the misdetection caused by the water surface or the ice surface by making the polarization direction of the emergent light parallel to the reflection plane, and improves the reliability of the laser ranging device.
In another embodiment, the embodiment of the present invention further provides a mobile platform, where the mobile platform includes any one of the above laser distance measuring devices and a platform body, and the laser distance measuring device is installed on the platform body. Further, the mobile platform includes at least one of an automobile, a robot, and a remote control car. When the distance measuring device is applied to an automobile, the platform body is the automobile body of the automobile. The vehicle may be an autonomous vehicle or a semi-autonomous vehicle, without limitation. When the distance measuring device is applied to the remote control car, the platform body is the car body of the remote control car. When the distance measuring device is applied to a robot, the platform body is the robot. When the distance measuring device is applied to a camera, the platform body is the camera itself.
The laser ranging device provided by each embodiment of the invention can be electronic equipment such as a laser radar, laser ranging equipment and the like. In one embodiment, the ranging device is used to sense external environmental information, such as distance information, orientation information, reflected intensity information, velocity information, etc. of environmental targets. In one implementation, the distance measuring device may detect the distance from the object to be measured to the distance measuring device by measuring the Time of Flight (TOF), which is the Time-of-Flight Time, of light propagation between the distance measuring device and the object to be measured. Alternatively, the distance measuring device may detect the distance from the object to be measured to the distance measuring device by other techniques, such as a distance measuring method based on phase shift (phase shift) measurement or a distance measuring method based on frequency shift (frequency shift) measurement, which is not limited herein.
For ease of understanding, the working flow of the distance measurement will be described below by way of example with reference to the laser distance measuring device 700 shown in fig. 7.
As shown in fig. 7, the laser ranging apparatus 700 may include a transmitting circuit 710, a receiving circuit 720, a sampling circuit 730, and an arithmetic circuit 740.
The transmit circuit 710 may transmit a sequence of laser pulses (e.g., a sequence of laser pulses). The receiving circuit 720 may receive the laser pulse sequence reflected by the object to be measured, perform photoelectric conversion on the laser pulse sequence to obtain an electrical signal, process the electrical signal, and output the electrical signal to the sampling circuit 730. The sampling circuit 730 may sample the electrical signal to obtain a sampling result. The arithmetic circuit 740 may determine the distance between the laser ranging device 700 and the object to be measured based on the sampling result of the sampling circuit 730.
Optionally, the laser distance measuring device 700 may further include a control circuit 750, where the control circuit 750 may implement control of other circuits, for example, may control an operating time of each circuit and/or perform parameter setting on each circuit, and the like.
It should be understood that, although 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 light beam to detect, the embodiment of the present application is not limited thereto, and the number of any one of the transmitting circuit, the receiving circuit, the sampling circuit and the arithmetic circuit may be at least two, and the at least two light beams are emitted in the same direction or in different directions respectively; the at least two light paths may be emitted simultaneously or at different times. In one example, the light emitting chips in the at least two transmitting circuits are packaged in the same module. For example, each transmitting circuit comprises a laser emitting chip, and die of the laser emitting chips in the at least two transmitting circuits are packaged together and accommodated in the same packaging space.
In some implementations, in addition to the circuit shown in fig. 7, the laser ranging apparatus 700 may further include a scanning module for changing the propagation direction of at least one laser pulse sequence emitted from the emitting circuit.
Here, a module including the transmitting circuit 710, the receiving circuit 720, the sampling circuit 730, and the operation circuit 740, or a module including the transmitting circuit 710, the receiving circuit 720, the sampling circuit 730, the operation circuit 740, and the control circuit 750 may be referred to as a ranging module, and the ranging module 750 may be independent of other modules, for example, a scanning module.
The distance measuring device can adopt a coaxial light path, namely the light beam emitted by the distance measuring device and the reflected light beam share at least part of the light path in the distance measuring device. For example, at least one path of laser pulse sequence emitted by the emitting circuit is emitted by the scanning module after the propagation direction is changed, and the laser pulse sequence reflected by the object to be detected is incident to the receiving circuit after passing through the scanning module. Alternatively, 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 one embodiment of the laser ranging device of the present invention using coaxial optical paths.
In the embodiment shown in fig. 8, the transmit and receive optical paths within the ranging apparatus are combined by the optical path changing element 806 before the collimating element 804, so that the transmit and receive optical paths can share the same collimating element, making the optical path more compact. In other implementations, the emitter 803 and the detector 805 may use respective collimating elements, and the optical path changing element 806 may be disposed in the optical path after the collimating elements.
In the embodiment shown in fig. 8, since the beam aperture of the light beam emitted from the emitter 803 is small and the beam aperture of the return light received by the distance measuring device is large, the optical path changing element can adopt a small-area mirror to combine the emission optical path and the reception optical path. In other implementations, the optical path changing element may also be a mirror with a through hole for transmitting the outgoing light from the emitter 803, and a mirror for reflecting the return light to the detector 805. Therefore, the shielding of the bracket of the small reflector to the return light can be reduced in the case of adopting the small reflector.
In the embodiment shown in FIG. 8, the optical path altering element is offset from the optical axis of the collimating element 804. In other implementations, the optical path altering element may also be located on the optical axis of the collimating element 804.
The laser ranging device 800 further comprises a scanning module 802. The scanning module 802 is disposed on an exit light path of the distance measuring module 801, and the scanning module 802 is configured to change a transmission direction of the collimated light beam 819 exiting from the collimating element 804, project the collimated light beam to an external environment, and project return light to the collimating element 804. The return light is focused by a collimating element 804 onto a detector 805.
In one embodiment, the scanning module 802 may include at least one optical element for altering the propagation path of the light beam, wherein the optical element may alter the propagation path of the light beam by reflecting, refracting, diffracting, etc., the light beam. For example, scanning module 802 includes a lens, mirror, prism, galvanometer, grating, liquid crystal, Optical Phased Array (Optical Phased Array), or any combination thereof. In one example, at least a portion of the optical element is moved, for example, by a driving module, and the moved optical element can reflect, refract, or diffract the light beam to different directions at different times. In some embodiments, multiple optical elements of the scanning module 802 can rotate or oscillate about a common axis of rotation 809, with each rotating or oscillating optical element serving to constantly change the direction of propagation of an incident beam. In one embodiment, the multiple optical elements of the scanning module 802 may rotate at different rotational speeds or oscillate at different speeds. In another embodiment, at least some of the optical elements of the scanning module 802 may rotate at substantially the same rotational speed. In some embodiments, the multiple optical elements of the scanning module may also be rotated about different axes. In some embodiments, the multiple optical elements of the scanning module may also rotate in the same direction, or in different directions; or in the same direction, or in different directions, without limitation.
In one embodiment, the scanning module 802 includes a first optical element 814 and a driver 816 coupled to the first optical element 814, the driver 816 configured to drive the first optical element 814 to rotate about a rotation axis 809 such that the first optical element 814 changes a direction of the collimated light beam 819. The first optical element 814 projects the collimated beams 819 into different directions. In one embodiment, the angle between the altered direction of the collimated light beam 819 through the first optical element and the axis of rotation 809 varies as the first optical element 814 rotates. In one embodiment, the first optical element 814 includes a pair of opposing non-parallel surfaces through which the collimated light beam 819 passes. In one embodiment, the first optical element 814 includes a prism having a thickness that varies along at least one radial direction. In one embodiment, the first optical element 814 includes a wedge angle prism that refracts the collimated beam 819.
In one embodiment, the scanning module 802 further comprises a second optical element 815, the second optical element 815 rotating about a rotation axis 809, the rotation speed of the second optical element 815 being different from the rotation speed of the first optical element 814. The second optical element 815 is used to redirect the light beam projected by the first optical element 814. In one embodiment, second optical element 815 is coupled to another actuator 817, which actuator 817 rotates second optical element 815. First optical element 814 and second optical element 815 may be driven by the same or different drivers, causing first optical element 814 and second optical element 815 to rotate at different speeds and/or turns, thereby projecting collimated light beam 819 into different directions in ambient space, allowing a large spatial range to be scanned. In one embodiment, controller 818 controls actuators 816 and 817 to actuate first optical element 814 and second optical element 815, respectively. The rotational speed of the first optical element 814 and the second optical element 815 may be determined according to the region and pattern of the desired scan in the actual application. The drives 816 and 817 may comprise motors or other drives.
In one embodiment, the second optical element 815 includes a pair of opposing non-parallel surfaces through which the light beam passes. In one embodiment, second optical element 815 includes a prism having a thickness that varies along at least one radial direction. In one embodiment, second optical element 815 includes a wedge angle prism.
In one embodiment, the scan module 802 further comprises a third optical element (not shown) and a driver for driving the third optical element to move. Optionally, the third optical element comprises a pair of opposed non-parallel surfaces through which the light beam passes. In one embodiment, the third optical element comprises a prism having a thickness that varies along at least one radial direction. In one embodiment, the third optical element comprises a wedge angle prism. At least two of the first, second and third optical elements rotate at different rotational speeds and/or rotational directions.
Rotation of the optical elements in the scanning module 802 may project light in different directions, such as directions 811 and 813, thus scanning the space around the laser ranging device 800. When the light 811 projected by the scanning module 802 strikes the object 810 to be measured, a portion of the light is reflected by the object 810 to be measured to the laser ranging device 800 in a direction opposite to the direction of the projected light 811. The return light 812 reflected by the object 810 to be measured enters the collimating element 804 after passing through the scanning module 802.
The detector 805 is placed on the same side of the collimating element 804 as the emitter 803, and the detector 805 is used to convert at least part of the return light passing through the collimating element 804 into an electrical signal.
In one embodiment, each optical element is coated with an antireflection coating. Alternatively, the thickness of the antireflection film may be equal to or close to the wavelength of the light beam emitted from the emitter 803, which may increase the intensity of the transmitted light beam.
In one embodiment, a filter layer is coated on a surface of a component in the distance measuring device, which is located on the light beam propagation path, or a filter is arranged on the light beam propagation path, and is used for transmitting at least a wave band in which the light beam emitted by the emitter is located and reflecting other wave bands, so as to reduce noise brought to the receiver by ambient light.
In some embodiments, the transmitter 803 may include a laser diode through which laser pulses in the order of nanoseconds are emitted. Further, the laser pulse reception 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 ranging apparatus 800 may calculate TOF using the pulse reception time information and the pulse emission time information, thereby determining the distance from the object 810 to be measured to the laser ranging apparatus 800.
The distance and orientation detected by laser rangefinder 800 may be used for remote sensing, obstacle avoidance, mapping, modeling, navigation, and the like. In one embodiment, the distance measuring device of the embodiment of the invention can be applied to a mobile platform, and the distance measuring device can be installed on a platform body of the mobile platform. The mobile platform with the distance measuring device can measure the external environment, for example, the distance between the mobile platform and an obstacle is measured for the purpose of avoiding the obstacle, and the external environment is mapped in two dimensions or three dimensions. In certain embodiments, the mobile platform comprises at least one of an unmanned automobile, a remote control car, a robot, a camera. When the distance measuring device is applied to an automobile, the platform body is the automobile body of the automobile. The vehicle may be an autonomous vehicle or a semi-autonomous vehicle, without limitation. When the distance measuring device is applied to the remote control car, the platform body is the car body of the remote control car. When the distance measuring device is applied to a robot, the platform body is the robot. When the distance measuring device is applied to a camera, the platform body is the camera itself.
Although the illustrative embodiments have been described herein with reference to the accompanying drawings, it is to be understood that the foregoing illustrative embodiments are merely exemplary and are not intended to limit the scope of the invention thereto. Various changes and modifications may be effected therein by one of ordinary skill in the pertinent art without departing from the scope or spirit of the present invention. All such changes and modifications are intended to be included within the scope of the present invention as set forth in the appended claims.
Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.
In the several embodiments provided in the present application, it should be understood that the disclosed apparatus and method may be implemented in other ways. For example, the above-described device embodiments are merely illustrative, and for example, the division of the units is only one logical functional division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another device, or some features may be omitted, or not executed.
In the description provided herein, numerous specific details are set forth. It is understood, however, that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.
Similarly, it should be appreciated that in the description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the invention and aiding in the understanding of one or more of the various inventive aspects. However, the method of the present invention should not be construed to reflect the intent: that the invention as claimed requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this invention.
It will be understood by those skilled in the art that all of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and all of the processes or elements of any method or apparatus so disclosed, may be combined in any combination, except combinations where such features are mutually exclusive. Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise.
Furthermore, those skilled in the art will appreciate that while some embodiments described herein include some features included in other embodiments, rather than other features, combinations of features of different embodiments are meant to be within the scope of the invention and form different embodiments. For example, in the claims, any of the claimed embodiments may be used in any combination.
The various component embodiments of the invention may be implemented in hardware, or in software modules running on one or more processors, or in a combination thereof. Those skilled in the art will appreciate that a microprocessor or Digital Signal Processor (DSP) may be used in practice to implement some or all of the functionality of some of the modules according to embodiments of the present invention. The present invention may also be embodied as apparatus programs (e.g., computer programs and computer program products) for performing a portion or all of the methods described herein. Such programs implementing the present invention may be stored on computer-readable media or may be in the form of one or more signals. Such a signal may be downloaded from an internet website or provided on a carrier signal or in any other form.
It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In the unit claims enumerating several means, several of these means may be embodied by one and the same item of hardware. The usage of the words first, second and third, etcetera do not indicate any ordering. These words may be interpreted as names.
Claims (10)
- The laser ranging device is characterized by comprising a transmitting module, wherein the transmitting module is used for transmitting laser pulses to detect an object to be measured, the laser pulses are linearly polarized light, the polarization direction of the linearly polarized light is parallel to a plane formed by the transmitting direction of the linearly polarized light and the normal direction of an interference surface, and the interference surface comprises a water surface or an ice surface.
- The laser ranging device as claimed in claim 1, wherein the emitting module comprises a laser, the laser is used for emitting the linearly polarized light, and the laser is arranged at an angle such that the polarization direction of the linearly polarized light is parallel to a plane formed by the emitting direction of the linearly polarized light and the normal direction of the interference surface.
- The laser ranging device as claimed in claim 1, wherein the emitting module comprises a laser and a half-wave plate arranged in front of the laser, wherein the laser is used for emitting 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 is used for rotating the polarization direction of the linearly polarized light emitted by the laser by 90 ° so that the polarization direction of the linearly polarized light after rotation is parallel to the plane formed by the emission direction of the linearly polarized light and the normal direction of the interference surface.
- The laser ranging device as claimed in claim 1 wherein said transmitting module comprises a laser for transmitting partially polarized light and a polarizer disposed in front of said laser, said polarizer causing said partially polarized light to become said linearly polarized light after passing through said polarizer.
- A laser ranging device as claimed in any of claims 2 to 4 wherein the laser comprises a semiconductor laser.
- The laser ranging device as claimed in claim 1, wherein the laser ranging device further comprises a detection module for receiving the light beam reflected by the object to be measured and converting the light beam into an electrical signal, and determining the distance between the object to be measured and the laser ranging device according to the electrical signal.
- The laser ranging device of claim 1 wherein the laser ranging device comprises a lidar.
- The laser ranging device as claimed in claim 6, further comprising:a scanning module;the transmitting module is used for transmitting a laser pulse sequence to the scanning module, the scanning module is used for changing the transmission direction of the laser pulse sequence and then emitting the laser pulse sequence, the laser pulse sequence reflected back by the object to be detected enters the detecting module after passing through the scanning module, and the detecting module is used for determining the distance and/or the direction of the object to be detected relative to the laser ranging device according to the reflected laser pulse sequence.
- A mobile platform, comprising:the laser ranging device of any one of claims 1 to 8; andthe laser ranging device is installed on the platform body.
- The mobile platform of claim 9, wherein the mobile platform comprises at least one of an automobile, a remote control car, or a robot.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/CN2018/125452 WO2020133384A1 (en) | 2018-12-29 | 2018-12-29 | Laser ranging device and mobile platform |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN111712734A true CN111712734A (en) | 2020-09-25 |
Family
ID=71128504
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201880069663.5A Pending CN111712734A (en) | 2018-12-29 | 2018-12-29 | Laser ranging device and mobile platform |
Country Status (2)
| Country | Link |
|---|---|
| CN (1) | CN111712734A (en) |
| WO (1) | WO2020133384A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113446963A (en) * | 2021-06-08 | 2021-09-28 | 同济大学 | Angle measuring system based on phased array and measuring method thereof |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112672006A (en) * | 2020-11-17 | 2021-04-16 | 钟能俊 | Automatic deicing system of camera |
Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101825711A (en) * | 2009-12-24 | 2010-09-08 | 哈尔滨工业大学 | 2 mu m all-fiber coherent laser Doppler wind finding radar system |
| US20110128525A1 (en) * | 2009-11-30 | 2011-06-02 | Denso Corporation | Light scanning device, laser radar device, and light scanning method |
| CN102707331A (en) * | 2012-06-08 | 2012-10-03 | 北京理工大学 | Receiving and transmitting integrated sub-nanosecond pulse laser detection system based on polarization |
| CN103197306A (en) * | 2013-04-18 | 2013-07-10 | 中国科学院光电技术研究所 | Full-aperture coaxial laser transmitting and echo receiving system |
| CN104777486A (en) * | 2015-02-04 | 2015-07-15 | 杨军 | Handheld laser short-distance measurement instrument |
| CN105116557A (en) * | 2015-09-18 | 2015-12-02 | 王治霞 | Light splitting slice, laser coaxial range finder and application thereof |
| CN105190158A (en) * | 2013-05-07 | 2015-12-23 | 皇家飞利浦有限公司 | Illumination device providing polarized light |
| CN105244747A (en) * | 2015-09-23 | 2016-01-13 | 中国工程物理研究院应用电子学研究所 | High-energy long pulse laser obtaining device, method and application |
| CN205067877U (en) * | 2015-09-18 | 2016-03-02 | 王治霞 | Divide slide and coaxial distancer of laser thereof |
| CN106569224A (en) * | 2016-10-31 | 2017-04-19 | 长春理工大学 | Scanning-type laser radar optical system |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2014089069A (en) * | 2012-10-29 | 2014-05-15 | Denso Corp | Rader system |
-
2018
- 2018-12-29 WO PCT/CN2018/125452 patent/WO2020133384A1/en active Application Filing
- 2018-12-29 CN CN201880069663.5A patent/CN111712734A/en active Pending
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20110128525A1 (en) * | 2009-11-30 | 2011-06-02 | Denso Corporation | Light scanning device, laser radar device, and light scanning method |
| CN101825711A (en) * | 2009-12-24 | 2010-09-08 | 哈尔滨工业大学 | 2 mu m all-fiber coherent laser Doppler wind finding radar system |
| CN102707331A (en) * | 2012-06-08 | 2012-10-03 | 北京理工大学 | Receiving and transmitting integrated sub-nanosecond pulse laser detection system based on polarization |
| CN103197306A (en) * | 2013-04-18 | 2013-07-10 | 中国科学院光电技术研究所 | Full-aperture coaxial laser transmitting and echo receiving system |
| CN105190158A (en) * | 2013-05-07 | 2015-12-23 | 皇家飞利浦有限公司 | Illumination device providing polarized light |
| CN104777486A (en) * | 2015-02-04 | 2015-07-15 | 杨军 | Handheld laser short-distance measurement instrument |
| CN105116557A (en) * | 2015-09-18 | 2015-12-02 | 王治霞 | Light splitting slice, laser coaxial range finder and application thereof |
| CN205067877U (en) * | 2015-09-18 | 2016-03-02 | 王治霞 | Divide slide and coaxial distancer of laser thereof |
| CN105244747A (en) * | 2015-09-23 | 2016-01-13 | 中国工程物理研究院应用电子学研究所 | High-energy long pulse laser obtaining device, method and application |
| CN106569224A (en) * | 2016-10-31 | 2017-04-19 | 长春理工大学 | Scanning-type laser radar optical system |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113446963A (en) * | 2021-06-08 | 2021-09-28 | 同济大学 | Angle measuring system based on phased array and measuring method thereof |
| CN113446963B (en) * | 2021-06-08 | 2022-06-21 | 同济大学 | Angle measuring system based on phased array and measuring method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2020133384A1 (en) | 2020-07-02 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN210038146U (en) | Distance measurement module, distance measurement device and movable platform | |
| CN111566510A (en) | Distance measuring device, balancing method of scanning view field of distance measuring device and mobile platform | |
| US20210341610A1 (en) | Ranging device | |
| CN111771136A (en) | Abnormity detection method, alarm method, distance measuring device and movable platform | |
| US20210333370A1 (en) | Light emission method, device, and scanning system | |
| CN209979845U (en) | Distance measuring device and mobile platform | |
| CN111587381A (en) | Method for adjusting motion speed of scanning element, distance measuring device and mobile platform | |
| WO2020154980A1 (en) | Method for calibrating external parameters of detection device, data processing device and detection system | |
| CN111712734A (en) | Laser ranging device and mobile platform | |
| CN210199305U (en) | Scanning module, range unit and movable platform | |
| WO2020113559A1 (en) | Ranging system and mobile platform | |
| WO2020177076A1 (en) | Detection apparatus initial-state calibration method and apparatus | |
| US20210341588A1 (en) | Ranging device and mobile platform | |
| WO2020237663A1 (en) | Multi-channel lidar point cloud interpolation method and ranging apparatus | |
| US20210333374A1 (en) | Ranging apparatus and mobile platform | |
| WO2020147121A1 (en) | Rainfall measurement method, detection device, readable storage medium | |
| WO2020237500A1 (en) | Ranging apparatus and method for controlling scanning field of view thereof | |
| WO2020107379A1 (en) | Reflectivity correction method for use in ranging apparatus, and ranging apparatus | |
| CN112654893A (en) | Motor rotating speed control method and device of scanning module and distance measuring device | |
| WO2020142909A1 (en) | Data synchronization method, distributed radar system and mobile platform | |
| US20210333369A1 (en) | Ranging system and mobile platform | |
| WO2022226984A1 (en) | Method for controlling scanning field of view, ranging apparatus and movable platform | |
| CN111684296A (en) | Radar access detection method, circuit and movable platform | |
| WO2020142879A1 (en) | Data processing method, detection device, data processing device and movable platform | |
| WO2022040937A1 (en) | Laser scanning device and laser scanning system |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| WD01 | Invention patent application deemed withdrawn after publication |
Application publication date: 20200925 |
|
| WD01 | Invention patent application deemed withdrawn after publication |