WO2022226984A1

WO2022226984A1 - Method for controlling scanning field of view, ranging apparatus and movable platform

Info

Publication number: WO2022226984A1
Application number: PCT/CN2021/091413
Authority: WO
Inventors: 梅雄泽; 王闯
Original assignee: 深圳市大疆创新科技有限公司
Priority date: 2021-04-30
Filing date: 2021-04-30
Publication date: 2022-11-03

Abstract

A method for controlling a scanning field of view, a ranging apparatus (100) and a movable platform. The ranging apparatus (100) comprises a transmitting module (110), a scanning module (202) and a control module (150), wherein the transmitting module (110) is used for transmitting an optical pulse sequence; the scanning module (202) comprises a rotating first optical element (214) and a rotating second optical element (215) which are used for sequentially changing the optical pulse sequence to be emitted in different propagation directions; and the control module (150) is used for controlling the ratio of the rotation speed of the first optical element (214) to a first parameter and the ratio of the rotation speed of the second optical element (215) to the first parameter to respectively be a first integer and a second integer, or the control module (150) is used for controlling the ratio of the rotation speed of the first optical element (214) to a second parameter and the ratio of the rotation speed of the second optical element (215) to the second parameter to respectively be a third integer and a fourth integer, wherein the first parameter comprises the ratio of 60 to an integration time, and the second parameter comprises the ratio of 30 to the integration time.

Description

Control method, distance measuring device and movable platform for scanning field of view

manual

technical field

The present invention generally relates to the technical field of ranging devices, and more particularly, to a control method for scanning a field of view, a ranging device and a movable platform.

Background technique

Lidar is a perception system for the outside world. Taking the lidar based on the time of flight (TOF) principle as an example, the lidar transmits pulses outward and receives echoes emitted by external objects. By measuring the delay of the echo, the distance between the object and the lidar in the emission direction can be calculated. By dynamically adjusting the outgoing direction of the laser, the distance information between objects in different directions and the lidar can be measured, thereby realizing the modeling of the three-dimensional space.

In the lidar, the dynamic adjustment of the direction of the lidar laser output is a key system function, which affects the spatial range (here refers to the field of view) that the system can detect, and the fineness of the obtained spatial information. In the lidar scanning scheme based on biprism, the combination of rotational speed of the biprism determines the scanning trajectory. The scanning trajectory is usually non-repetitive, and is prone to smear problems for some application scenarios, which has a negative impact on object recognition.

Therefore, in view of the existence of the above problems, the present application proposes a control method for scanning a field of view, a distance measuring device and a movable platform.

SUMMARY OF THE INVENTION

The present invention has been made to solve at least one of the above-mentioned problems. Specifically, one aspect of the present invention provides a distance measuring device, comprising:

The transmitting module is used to transmit the light pulse sequence;

a scanning module, the scanning module includes a rotating first optical element and a rotating second optical element, and is used to sequentially change the light pulse sequence to different propagation directions for output to form a scanning field of view;

a control module, configured to control the ratio of the rotation speed of the first optical element to the first parameter to be a first integer, and to control the ratio of the rotation speed of the second optical element to the first parameter to be a second integer, In order to control the formation of the scanning field of view with the first scanning pattern, or for controlling the ratio of the rotation speed of the first optical element to the second parameter to be a third integer, and to control the rotation speed of the second optical element and The ratio of the second parameter is a fourth integer to control the formation of the scanning field of view with the second scanning pattern, wherein the first parameter includes a ratio of 60 to the integration time, and the second parameter includes 30 to the integration time ratio.

Another aspect of the present invention provides a control method for scanning a field of view, the method comprising:

transmit a sequence of light pulses;

The ratio of the rotation speed of the first optical element to the first parameter is controlled to be a first integer, and the ratio of the rotation speed of the second optical element to the first parameter is controlled to be a second integer, so as to sequentially change the optical pulse sequence Exiting to different propagation directions to form a scanning field of view with a first scanning pattern, or, controlling the ratio of the rotation speed of the first optical element to the second parameter to be a third integer, and controlling the rotation of the second optical element The ratio of the speed to the second parameter is a fourth integer, so as to sequentially change the light pulse sequence to different propagation directions to form a scanning field of view with a first scanning pattern, wherein the first parameter includes 60 and 60 The ratio of the integration time, the second parameter includes the ratio of 30 to the integration time.

Another aspect of the present invention provides a movable platform, the movable platform includes:

Movable platform body;

At least one of the aforementioned distance measuring devices is provided on the movable platform body.

According to the distance measuring device of the embodiment of the present invention, by controlling the ratio of the rotation speed of the first optical element to the first parameter to be a first integer, and controlling the ratio of the rotation speed of the second optical element to the first parameter The ratio is a second integer to constrain the rotation speed of the optical element in the scanning module of the ranging device, so as to realize repeated scanning and improve the coverage and distribution uniformity of the scanning trajectory in the scanning field of view. When the ratio of the rotation speed of an optical element to the second parameter is a third integer, and the ratio of the rotation speed of the second optical element to the second parameter is controlled to be a fourth integer, the smear problem can be solved, which can be used as The basis of the follow-up algorithm makes the identification method of the follow-up object more accurate and reduces the processing errors caused by the smear problem.

Description of drawings

In order to illustrate the technical solutions in the embodiments of the present invention more clearly, the following briefly introduces the accompanying drawings used in the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained from these drawings without creative labor.

FIG. 1 shows a schematic structural diagram of a ranging apparatus in an embodiment of the present invention;

FIG. 2 shows a schematic diagram of a distance measuring device in an embodiment of the present invention;

3 shows a schematic diagram of a conventional scanning pattern of the ranging device;

FIG. 4 shows a schematic diagram of another conventional scanning pattern of the ranging device;

5 shows a schematic diagram of a first scanning pattern of a ranging device in an embodiment of the present invention;

6 shows a schematic diagram of a first scanning pattern of a distance measuring device in another embodiment of the present invention;

FIG. 7 shows a schematic diagram of a second scanning pattern of a ranging device in an embodiment of the present invention;

FIG. 8 shows a schematic diagram of a scanning pattern of a distance measuring device in another embodiment of the present invention;

FIG. 9 shows a schematic flowchart of a control method for scanning a field of view in an embodiment of the present invention.

Detailed ways

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. Obviously, the described embodiments are only some of the embodiments of the present invention, not all of the embodiments of the present invention, and it should be understood that the present invention is not limited by the example embodiments described herein. Based on the embodiments of the present invention described in the present invention, all other embodiments obtained by those skilled in the art without creative efforts shall fall within the protection scope of the present 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 details. In other instances, some technical features known in the art have not been described in order to avoid obscuring the present invention.

It should be understood that the present invention may be embodied in 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/the" are intended to include the plural forms as well, unless the context clearly dictates otherwise. It should also be understood that the terms "compose" and/or "include", when used in this specification, identify the presence of stated features, integers, steps, operations, elements and/or components, but do not exclude one or more other The presence or addition of features, integers, steps, operations, elements, parts and/or groups. As used herein, the term "and/or" includes any and all combinations of the associated listed items.

For a thorough understanding of the present invention, detailed structures will be presented in the following description in order to explain the technical solutions proposed by the present invention. Alternative embodiments of the present invention are described in detail below, however, the invention is capable of other embodiments in addition to these detailed descriptions.

The present application will be described in detail below with reference to the accompanying drawings. The features of the embodiments and implementations described below may be combined with each other without conflict.

First, the structure of a ranging device in an embodiment of the present invention is described in detail and exemplarily with reference to FIG. 1 and FIG. 2 . The ranging device includes a laser radar. The ranging device is only used as an example. For other suitable ranging devices Also applicable to this application. The ranging device can be used to perform the control method of scanning the field of view herein.

The solutions provided by the various embodiments of the present invention can be applied to a ranging device, and the ranging device can be an electronic device such as a laser radar or a laser ranging device. In one embodiment, the ranging device is used to sense external environmental information, for example, distance information, orientation information, reflection intensity information, speed information and the like of environmental objects. In an implementation manner, the ranging device can detect the distance from the detected object to the ranging device by measuring the time of light propagation between the ranging device and the detected object, that is, Time-of-Flight (TOF). Alternatively, the ranging device can also detect the distance from the detected object to the ranging device through other technologies, such as a ranging method based on phase shift measurement, or a ranging method based on frequency shift measurement. This does not limit.

For ease of understanding, the working process of ranging will be described by way of example below with reference to the ranging apparatus 100 shown in FIG. 1 .

As an example, the ranging apparatus 100 includes a transmitting module 110 , a scanning module 202 , a control module 150 and a detection module, and the detection module includes a receiving circuit 120 , a sampling circuit 130 and an arithmetic circuit 140 . The transmitting module is used for transmitting the light pulse sequence to detect the target scene; the scanning module 202 is used for changing the propagation paths of the light pulse sequence emitted by the transmitting module to different directions in turn to form a scanning field of view; the detecting module is used for receiving The light pulse sequence reflected back by the object, and the distance and/or orientation of the object relative to the ranging device is determined according to the reflected light pulse sequence, so as to generate the point cloud point.

The transmitting module 110 may emit a sequence of light pulses (eg, a sequence of laser pulses). The receiving circuit 120 can receive the optical pulse sequence reflected by the object to be detected, that is, obtain the pulse waveform of the echo signal through it, and perform photoelectric conversion on the optical pulse sequence to obtain an electrical signal, and then process the electrical signal to obtain an electrical signal. output to the sampling circuit 130 . The sampling circuit 130 may sample the electrical signal to obtain a sampling result. The arithmetic circuit 140 may determine the distance, that is, the depth, between the distance measuring device 100 and the detected object based on the sampling result of the sampling circuit 130 .

Optionally, the distance measuring device 100 may further include a control module 150, and the control module 150 may control other circuits or modules, for example, may control the working time of each circuit or module and/or perform parameter settings, etc.

It should be understood that although the distance measuring device shown in FIG. 1 includes a transmitting module, a receiving circuit, a sampling circuit and an arithmetic circuit for emitting a beam of light for detection, the embodiment of the present application is not limited to this, the transmitting module The number of any one of the receiving circuits, sampling circuits, and arithmetic circuits may also be at least two, for emitting at least two light beams in the same direction or in different directions respectively; wherein, the at least two light beam paths can be simultaneously The ejection can also be ejected at different times. In one example, the light-emitting chips in the at least two emission modules are packaged in the same module. For example, each emitting module includes one laser emitting chip, and the dies in the laser emitting chips in the at least two emitting modules are packaged together and accommodated in the same packaging space.

In some implementations, as shown in FIG. 1 , the ranging device 100 may further include a scanning module 202 for changing the propagation direction of at least one optical pulse sequence (eg, a laser pulse sequence) emitted by the emission module to output the field of view. scanning. Exemplarily, the scanning area of the scanning module 202 within the field of view of the ranging device increases over time.

Wherein, the module including the transmitting module 110, the receiving circuit 120, the sampling circuit 130 and the operation circuit 140, or the module including the transmitting module 110, the receiving circuit 120, the sampling circuit 130, the operation circuit 140 and the control module 150 may be referred to as the measuring circuit A ranging module, which can be independent of other modules, such as the scanning module 202 .

A coaxial optical path may be used in the ranging device, that is, the light beam emitted by the ranging device and the reflected light beam share at least part of the optical path in the ranging device. For example, after at least one laser pulse sequence emitted by the transmitting module changes its propagation direction and exits through the scanning module, the laser pulse sequence reflected by the detection object passes through the scanning module and then enters the receiving circuit. 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 respectively transmitted along different optical paths in the distance-measuring device. FIG. 2 shows a schematic diagram of an embodiment in which the distance measuring device of the present invention adopts a coaxial optical path.

The ranging device 200 includes a ranging module 210, and the ranging module 210 includes a transmitter 203 (which may include the above-mentioned transmitting module), a collimating element 204, a detector 205 (which may include the above-mentioned receiving circuit, sampling circuit and arithmetic circuit) and Optical path changing element 206 . The ranging module 210 is used for emitting a light beam, receiving the returning light, and converting the returning light into an electrical signal. Among them, the transmitter 203 can be used to transmit a sequence of optical pulses. In one embodiment, the transmitter 203 may emit a sequence of laser pulses. Optionally, the laser beam emitted by the transmitter 203 is a narrow bandwidth beam with a wavelength outside the visible light range. The collimating element 204 is disposed on the outgoing light path of the transmitter, and is used for collimating the light beam emitted from the transmitter 203, and collimating the light beam emitted by the transmitter 203 into parallel light and outputting to the scanning module. The collimating element also serves to converge at least a portion of the return light reflected by the probe. The collimating element 204 may be a collimating lens or other elements capable of collimating light beams.

In the embodiment shown in FIG. 2, the transmitting optical path and the receiving optical path in the ranging device are combined by the optical path changing element 206 before the collimating element 204, so that the transmitting optical path and the receiving optical path can share the same collimating element, so that the optical path more compact. In some other implementations, the emitter 203 and the detector 205 may use respective collimating elements, and the optical path changing element 206 may be arranged on the optical path behind the collimating element.

In the embodiment shown in FIG. 2 , since the beam aperture of the beam emitted by the transmitter 203 is small, and the beam aperture of the return light received by the ranging device is relatively large, the optical path changing element can use a small-area reflective mirror to The transmit light path and the receive light path are combined. In some other implementations, the optical path changing element may also use a reflector with a through hole, wherein the through hole is used to transmit the outgoing light of the emitter 203 , and the reflector is used to reflect the return light to the detector 205 . In this way, in the case of using a small reflector, the occlusion of the return light by the support of the small reflector can be reduced.

In the embodiment shown in FIG. 2 , the optical path altering element is offset from the optical axis of the collimating element 204 . In some other implementations, the optical path altering element may also be located on the optical axis of the collimating element 204 .

The ranging device 200 further includes a scanning module 202 . The scanning module 202 is placed on the outgoing optical path of the ranging module 210 . The scanning module 202 is used to change the transmission direction of the collimated beam 219 emitted by the collimating element 204 and project it to the external environment, and project the return light to the collimating element 204 . The returned light is focused on the detector 205 through the collimating element 204 .

In one embodiment, the scanning module 202 can include at least one optical element for changing the propagation path of the light beam, wherein the optical element can change the propagation path of the light beam by reflecting, refracting, diffracting the light beam, etc. The optical element includes at least one light-refractive element having non-parallel exit and entrance surfaces. For example, 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. In one example, at least part of the optical elements are moving, for example, the at least part of the optical elements are driven to move by a driving module, and the moving optical elements can reflect, refract or diffract the light beam to different directions at different times. In some embodiments, the multiple optical elements of the scanning module 202 may be rotated or oscillated about a common axis 209, each rotating or oscillating optical element being used to continuously change the propagation direction of the incident beam. In one embodiment, the plurality of optical elements of the scanning module 202 may rotate at different rotational speeds, or vibrate at different speeds. In another embodiment, at least some of the optical elements of scan module 202 may rotate at substantially the same rotational speed. In some embodiments, the plurality of optical elements of the scanning module may also be rotated about different axes. In some embodiments, the plurality of 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 are not limited herein.

In one embodiment, the scanning module 202 includes a first optical element 214 and a driver 216 connected to the first optical element 214, and the driver 216 is used to drive the first optical element 214 to rotate around the rotation axis 209, so that the first optical element 214 changes The direction of the collimated beam 219. The first optical element 214 projects the collimated beam 219 in different directions. In one embodiment, the angle between the direction of the collimated light beam 219 changed by the first optical element and the rotation axis 209 changes with the rotation of the first optical element 214 . In one embodiment, the first optical element 214 includes a pair of opposing non-parallel surfaces through which the collimated beam 219 passes. In one embodiment, the first optical element 214 includes a prism whose thickness varies along at least one radial direction. In one embodiment, the first optical element 214 includes a wedge prism that refracts the collimated light beam 219 .

In one embodiment, the scanning module 202 further includes a second optical element 215 , the second optical element 215 rotates around the rotation axis 209 , and the rotation speed of the second optical element 215 is different from the rotation speed of the first optical element 214 . The second optical element 215 is used to change the direction of the light beam projected by the first optical element 214 . In one embodiment, the second optical element 215 is connected to another driver 217, and the driver 217 drives the second optical element 215 to rotate. The first optical element 214 and the second optical element 215 can be driven by the same or different drivers, so that the rotational speed and/or steering of the first optical element 214 and the second optical element 215 are different, thereby projecting the collimated beam 219 into the external space Different directions can scan a larger spatial range. In one embodiment, the controller 218 controls the

drivers

216 and 217 to drive the first optical element 214 and the second optical element 215, respectively. The rotational speeds of the first optical element 214 and the second optical element 215 may be determined according to the area and pattern expected to be scanned in practical applications.

Drives

216 and 217 may include motors or other drives. Optionally, the rotation directions (also referred to as steering directions herein) of the first optical element 214 and the second optical element 215 are the same, or the rotation directions of the first optical element and the second optical element are different.

In one embodiment, the second optical element 215 includes a pair of opposing non-parallel surfaces through which the light beam passes. In one embodiment, the second optical element 215 comprises a prism whose thickness varies along at least one radial direction. In one embodiment, the second optical element 215 comprises a wedge prism.

In one embodiment, the scanning module 202 further includes a third optical element (not shown) and a driver for driving the movement of the third optical element. Optionally, the third optical element includes a pair of opposing non-parallel surfaces through which the light beam passes. In one embodiment, the third optical element comprises a prism of varying thickness along at least one radial direction. In one embodiment, the third optical element comprises a wedge prism. At least two of the first, second and third optical elements rotate at different rotational speeds and/or rotations.

In one embodiment, the scanning module includes two or three of the light refraction elements sequentially arranged on the outgoing light path of the light pulse sequence. Optionally, at least two of the light refraction elements in the scanning module are rotated during the scanning process to change the direction of the light pulse sequence.

The scanning paths of the scanning module are different at least at some different times. The rotation of each optical element in the scanning module 202 can project light in different directions, such as the direction of the projected light 211 and the direction 213 . space to scan. When the light 211 projected by the scanning module 202 hits the detected object 201 , a part of the light is reflected by the detected object 201 to the distance measuring device 200 in a direction opposite to the projected light 211 . The returning light 212 reflected by the probe 201 passes through the scanning module 202 and then enters the collimating element 204 .

A detector 205 is placed on the same side of the collimating element 204 as the emitter 203, and the detector 205 is used to convert at least part of the return light passing through the collimating element 204 into an electrical signal.

In one embodiment, each optical element is coated with an anti-reflection coating. Optionally, the thickness of the anti-reflection film is equal to or close to the wavelength of the light beam emitted by the emitter 203, which can increase the intensity of the transmitted light beam.

In one embodiment, a filter layer is coated on the surface of an element located on the beam propagation path in the distance measuring device, or a filter is provided on the beam propagation path for transmitting at least the wavelength band of the light beam emitted by the transmitter, Reflects other bands to reduce noise from ambient light to the receiver.

In some embodiments, the transmitter 203 may comprise a laser diode through which laser pulses are emitted on the nanosecond scale. Further, the laser pulse receiving time can be determined, for example, by detecting the rising edge time and/or the falling edge time of the electrical signal pulse to determine the laser pulse receiving time. In this way, the ranging apparatus 200 can calculate the TOF by using the pulse receiving time information and the pulse sending time information, so as to determine the distance from the probe 201 to the ranging apparatus 200 . The distance and orientation detected by the ranging device 200 can be used for remote sensing, obstacle avoidance, mapping, modeling, navigation, and the like.

In the lidar scanning scheme based on biprism, the combination of rotational speed of biprism determines the scanning trajectory. Although the scanning trajectory has certain rules to follow, it is usually non-repetitive. In the conventional scanning scheme of lidar, there is no specific constraint on the rotational speed between prisms, and a suitable combination is often found through simulation analysis to obtain a relatively more uniform scanning trajectory in space. When the difference in rotational speed between the two prisms is small, for example, the rotational speeds of the two prisms are 9319rpm and 6392rpm, and the integration time is 0.1s, a scanning pattern composed of the scanning trajectory shown in Figure 3 will appear. When it is large, for example, the rotational speeds of the two prisms are 9319rpm and -6392rpm, respectively, and the integration time is 0.1s, a scanning pattern composed of the scanning trajectory shown in Figure 4 will be presented. The scanning pattern herein may refer to a pattern formed by the accumulation of scanning trajectories of a light beam within a scanning field of view over a period of time. Under the scanning of the scanning module, after the light beam forms a complete scanning pattern in one scanning period, it starts to form the next complete, same or different scanning pattern in the next scanning period.

Both of the above two scan estimations have problems of non-repetition and smear. Among them, non-repetition means that the scanning trajectories between consecutive frames are different, causing confusion to the user, and, within one frame, the center of the scanning trajectory, etc. The direction will be scanned multiple times. The time difference between the first and last scanning in the same direction (and its vicinity) can be up to 0.1s. Taking the lidar as a reference, if the moving speed of the object to be measured is 72km/h, then the object Moving 2m within 0.1s is equivalent to forming a frame of point clouds detected by the same object at different positions, and there will be a problem of smearing. The existence of the smearing problem will have a negative impact on the recognition of the object. Affect the precision and accuracy of recognition.

In view of the existence of the above problems, as shown in FIG. 2 , the control module of the ranging device in the embodiment of the present invention (for example, the controller 218 in FIG. 2 ) is also used to: control the rotation speed of the first optical element 214 and the first parameter The ratio of φ to φ is a first integer, and the ratio of the rotational speed of the second optical element 215 to the first parameter is controlled to be a second integer, so as to control the formation of the scanning field of view with the first scanning pattern, or to control the first optical element The ratio of the rotational speed of the second optical element 214 to the second parameter is a third integer, and the ratio of the rotational speed of the second optical element 215 to the second parameter is controlled to be a fourth integer, so as to control the formation of the scanning field of view having the second scanning pattern, wherein , the first parameter includes the ratio of 60 to the integration time, and the second parameter includes the ratio of 30 to the integration time. According to the distance measuring device of the embodiment of the present invention, by controlling the ratio of the rotation speed of the first optical element to the first parameter to be a first integer, and controlling the ratio of the rotation speed of the second optical element to the first parameter to be a second integer, In order to constrain the rotation speed of the optical element in the scanning module of the ranging device, repeated scanning can be realized, and the coverage and distribution uniformity of the scanning trajectory in the scanning field of view can be improved. When the ratio of the two parameters is the third integer, and the ratio of the rotation speed of the second optical element to the second parameter is the fourth integer, the smear problem can be solved, which can be used as the basis for the subsequent algorithm, so that the identification method of the subsequent object can be It is more accurate and reduces the processing errors caused by the smear problem.

Optionally, the first parameter is the ratio of 60 to the integration time, and the second parameter is the ratio of 30 to the integration time, wherein the integration time can be any time, for example, the integration time can be between 0.1s and 1s. Arbitrary time, more specifically, the integration time is, for example, 0.1s, 0.2s, 0.3s, 0.4s, 0.5s, or the like.

The integration time may be determined based on user instructions, or the integration time may also be a preset value in the distance measuring device, or the integration time may be adjusted as required.

In one example, as shown in FIG. 2 , the control module such as the controller 218 is further configured to: select one of the first parameter and the second parameter based on a user instruction, for controlling the rotational speed of the first optical element 214 and the first parameter The rotational speed of the second optical element 215 . Or, in other examples, the control module may also automatically select one of the first parameter and the second parameter according to the current application scenario of the ranging device, for controlling the rotational speed of the first optical element 214 and the second optical element Rotation speed of element 215 . For example, when the repeatability of some required scanning patterns is good, for example, when the scanning trajectories in each frame of scanning patterns are required to be substantially the same, the first parameter is selected to control the rotational speed of the first optical element 214 and the second optical element. 215 rotation speed; for example, for vehicle driving, rail transit and other application scenarios, since the ranging device is usually in a moving state in these scenarios, the second parameter is selected to control the rotation speed of the first optical element 214 and the second optical element 214. The rotation speed of the element 215 can well avoid the smear problem, which is beneficial to improve the recognition accuracy of objects (such as obstacles) and ensure the safety of driving.

When selecting the first parameter, assuming that the integration time of each frame is t0, when the ratio of the rotation speed of the first optical element and the rotation speed of the second optical element to the first parameter (ie 60/t0) is the first When the integer n1 and the second integer n2 are used, repeated scanning can be achieved, because under this rotational speed constraint, the first optical element and the second optical element return to the initial angle every time t0 elapses, and regardless of the starting point of the integration at The pattern is the same wherever you get it.

The difference between the first integer and the second integer can be any value, and the difference between the two can be reasonably set according to the requirements, so as to constrain the rotation speed of the first optical element and the rotation speed of the second optical element, For example, the difference between the first integer and the second integer may be between [0, 100], and further between [0, 50], and for example, the difference between the first integer and the second integer may be between [0, 20 ], in a specific example, when the difference between the first integer n1 and the second integer n2 is 1, the coverage ratio of the scanning track in the scanning field of view reaches the maximum.

In one example, the difference between the first integer and the second integer is the first difference, the difference between the first integer and the second integer is the second difference, and when the second difference is greater than the first difference, then The coverage ratio of the scanning track corresponding to the second difference in the scanning field of view is smaller than the coverage ratio of the scanning track corresponding to the first difference in the scanning field of view. Optionally, the first difference value and the second difference value may correspond to the same integration time. For example, when the rotational speed of the first optical element and the rotational speed of the second optical element are 9000rpm and 9600rpm, respectively, the integration time is 0.1s, n1 is 15, and n2 is 16, the scanning pattern corresponding to the scanning field of view is formed. As shown in Figure 5. For another example, when the rotational speed of the first optical element and the rotational speed of the second optical element are 9000rpm and 10200rpm, respectively, the integration time is 0.1s, n1 is 15, and n2 is 17, the scan field corresponding to the formed scan field The pattern, as shown in Fig. 6, in which, since each direction in Fig. 6 is scanned twice, the coverage of the scanning track in the scanning pattern in Fig. 6 in the field of view is lower than that in the scanning pattern in Fig. 5. Coverage within the field of view.

In one example, the scan trajectory of the scan points in the first scan pattern is substantially a spiral, and the start and end points of the scan trajectory in the first scan pattern are located at the same position within the scan field of view. The starting point of the scanning track of the first scanning pattern can be at any position in the field of view, and the position of the starting point can be controlled based on the angle difference between the first optical element and the second optical element.

When selecting the second parameter, assuming that the integration time of each frame is t0, when the ratio of the rotation speed of the first optical element and the rotation speed of the second optical element to the second parameter (ie 30/t0) is the third When the integer n3 and the fourth integer n4 are used, and the starting point of the integration (that is, the starting point of the scanning trajectory) is at the center or edge of the scanning field of view, a scanning field of view with the second scanning pattern can be obtained, thereby solving the smear problem. Since the time difference between the first and last scans in the same direction (and its vicinity) is very small under the constraints of the rotation speed and the starting point (the center of the scanning field or the edge of the scanning field), the distance the object moves is very small , the smear problem can be ignored, and the scanning direction will return to the next starting point (edge or center) every time t0 elapses. The scanning trajectory of the scanning points in the second scanning pattern is generally a spiral line. In one example, the scanning track in the second scanning pattern starts from the center of the scanning field of view and ends at the edge of the scanning field of view, or the scanning track in the second scanning pattern starts from the edge of the scanning field of view to scan The center of the field of view is the end point. A second scan pattern of two different patterns can be obtained starting from the center of the scan field or the edge of the scan field, but it can be repeated.

In one example, as shown in FIG. 2 , the control module (eg, the controller 218 ) is further configured to: control the angular difference between the first optical element 214 and the second optical element 215 so that the starting points of the respective integration times correspond to The starting point of the scanning trajectory is located at the center or edge of the second scanning pattern (ie, at the scanning field of view). For example, when the angle difference between the first optical element 214 and the second optical element 215 is 0° or 360°, the starting point of the scanning track is located at the edge of the second scanning pattern, and when the difference between the first optical element and the second optical element is 0° or 360° When the angle difference between them is 180°, the starting point of the scanning track is located at the center of the second scanning pattern.

The difference between the third integer and the fourth integer can be reasonably set according to actual needs. For example, the difference between the two can be 1, 2, 3, 4, 5, etc. In a specific example, the control module is also used to: The difference between the third integer and the fourth integer is controlled to be 1.

In an example, when the rotation speed of the first optical element is 9000rpm, the rotation speed of the second optical element is 9300rpm, and the integration time is 0.1s, then the third integer n3 is 30, and the fourth integer n4 is 31, then we can obtain The second scanning pattern shown in FIG. 7 , in which the left image is the center of the scanning field of view as the starting point, and the right image is the edge of the scanning field of view as the starting point.

If the two frames of scan data shown in Figure 7 are combined, that is, the integration time is changed to 2*t0, the scanning pattern will be as shown in Figure 8. No matter where the starting point of the integration is, the pattern obtained is the same, and repeated scanning can be realized.

In the present application, the rotational speed of the first optical element 214 may be determined based on the rotational speed of the driver 216 of the first optical element, such as a motor, and the rotational speed of the second optical element 215 may be determined based on the rotational speed of the driver 217 of the second optical element 215, such as a motor. speed to be determined.

The range of the rotation speed of the first optical element and the rotation speed of the second optical element can be reasonably set according to actual needs. For example, the rotation speed of the first optical element can be between [1000rpm, 20000rpm], the rotation speed of the second optical element The speed can be between [1000rpm, 20000rpm], and the ratio of the rotation speed of the first optical element and the rotation speed of the second optical element to the first parameter is an integer, or, the rotation speed of the first optical element and the second optical element are integers. The ratio of the rotational speed of the element to the second parameter is an integer.

To sum up, according to the distance measuring device of the present application, the ratio of the rotational speed of the first optical element to the first parameter is controlled to be a first integer, and the ratio of the rotational speed of the second optical element to the first parameter is controlled to be a second integer , in order to constrain the rotation speed of the optical element in the scanning module of the ranging device, so as to realize repeated scanning and improve the coverage and distribution uniformity of the scanning trajectory in the scanning field of view. When the ratio of the second parameter is the third integer, and the ratio of the rotational speed of the second optical element to the second parameter is controlled to be the fourth integer, the smear problem can be solved, which can be used as the basis of the subsequent algorithm to enable the identification method of the subsequent object It can be more accurate and reduce the processing errors caused by the smear problem.

Next, the control method of the scanning field of view of the present invention will be described with reference to FIG. 9 , wherein FIG. 9 shows a schematic flowchart of the control method of the scanning field of view in an embodiment of the present invention. The control method of the present application is based on the foregoing distance measuring device as the execution subject. Specifically, for some details of the method, reference may be made to the foregoing description of the distance measuring device.

As an example, the control method for scanning the field of view according to the embodiment of the present invention includes the following steps S901 to S902.

First, in step S901, a sequence of light pulses is emitted. Next, in step S902, the ratio of the rotation speed of the first optical element to the first parameter is controlled to be a first integer, and the ratio of the rotation speed of the second optical element to the first parameter is controlled to be a second integer, so as to sequentially order the optical pulse sequence Change to different propagation directions to form a scanning field of view with a first scanning pattern, or control the ratio of the rotational speed of the first optical element to the second parameter to be a third integer, and control the rotational speed of the second optical element to be proportional to the first The ratio of the two parameters is a fourth integer, so as to sequentially change the light pulse sequence to different propagation directions to form a scanning field of view with a first scanning pattern, wherein the first parameter includes the ratio of 60 to the integration time, and the second parameter includes The ratio of 30 to the integration time.

Exemplarily, before transmitting the light pulse sequence, the control method further includes: selecting one of the first parameter and the second parameter based on a user instruction. One of the first parameter and the second parameter may be selected by acquiring a user instruction input by the user through the user interaction interface, and based on the user instruction.

Exemplarily, the control method further includes: controlling the angle difference between the first optical element and the second optical element, so that the starting point of the scanning track corresponding to the starting point of each integration time is located at the center or edge of the second scanning pattern. Optionally, when the angle difference between the first optical element and the second optical element is 0° or 360°, the starting point of the scanning track is located at the edge of the second scanning pattern. When the angle difference between them is 180°, the starting point of the scanning track is located at the center of the second scanning pattern.

In one example, the control method further includes: controlling the difference between the first integer and the second integer to be 1, or any other suitable value. The scanning trajectory of the scanning points in the first scanning pattern is generally a spiral line. Optionally, the start point and the end point of the scanning trajectory in the first scanning pattern are located at the same position in the scanning field of view.

In one example, the difference between the first integer and the second integer is the first difference, the difference between the first integer and the second integer is the second difference, and when the second difference is greater than the first difference, then The coverage ratio of the scanning track corresponding to the second difference in the scanning field of view is smaller than the coverage ratio of the scanning track corresponding to the first difference in the scanning field of view.

In one example, the control method further includes: controlling the difference between the third integer and the fourth integer to be 1, or any other suitable value. The scanning trajectory of the scanning points in the second scanning pattern is generally a spiral line. Each scanning track in the second scanning pattern starts from the center of the scanning field of view and ends at the edge of the scanning field of view, or each scanning track in the second scanning pattern starts from the edge of the scanning field of view and ends at the edge of the scanning field of view. The center of the field is the end point.

In one example, the control method further includes: receiving a sequence of light pulses reflected back by the object, and determining a distance and/or orientation of the object relative to the control method according to the sequence of reflected light pulses.

To sum up, according to the control method of the present application, by controlling the ratio of the rotation speed of the first optical element to the first parameter to be a first integer, and controlling the ratio of the rotation speed of the second optical element to the first parameter to be a second integer, In order to constrain the rotation speed of the optical element in the scanning module of the ranging device, repeated scanning can be realized, and the coverage and distribution uniformity of the scanning trajectory in the scanning field of view can be improved. When the ratio of the two parameters is the third integer, and the ratio of the rotation speed of the second optical element to the second parameter is the fourth integer, the smear problem can be solved, which can be used as the basis for the subsequent algorithm, so that the identification method of the subsequent object can be It is more accurate and reduces the processing errors caused by the smear problem.

In one embodiment, the distance measuring device of the embodiment of the present invention can be applied to a movable platform, and the distance measuring device can be installed on the platform body of the movable platform. The movable platform with the distance measuring device can measure the external environment, for example, measure the distance between the movable platform and obstacles for obstacle avoidance and other purposes, and perform two-dimensional or three-dimensional mapping of the external environment. In some embodiments, the movable platform includes at least one of an unmanned aerial vehicle, a car, a remote control car, a robot, a boat, a camera. When the ranging device is applied to the unmanned aerial vehicle, the platform body is the fuselage of the unmanned aerial vehicle. When the ranging device is applied to an automobile, the platform body is the body of the automobile. The vehicle may be an autonomous driving vehicle or a semi-autonomous driving vehicle, which is not limited herein. When the distance measuring device is applied to the remote control car, the platform body is the body of the remote control car. When the distance measuring device is applied to the robot, the platform body is the robot. When the ranging device is applied to the camera, the platform body is the camera itself.

The movable platform in the embodiment of the present invention includes the aforementioned distance measuring device, so the movable platforms all have the same advantages as the aforementioned distance measuring device.

In addition, an embodiment of the present invention further provides a computer storage medium, on which a computer program is stored. One or more computer program instructions may be stored on the computer-readable storage medium, and the processor may execute the program instructions stored in the memory to implement the functions (implemented by the processor) in the embodiments of the present invention described herein and/or other desired functions, such as to execute corresponding steps of the control method for scanning the field of view according to the embodiment of the present invention, various application programs and various data, such as all various data used and/or generated by the application.

For example, the computer storage medium may include, for example, a memory card for a smartphone, a storage unit for a tablet computer, a hard disk for a personal computer, read only memory (ROM), erasable programmable read only memory (EPROM), portable compact disk Read only memory (CD-ROM), USB memory, or any combination of the above storage media. The computer-readable storage medium can be any combination of one or more computer-readable storage media. For example, a computer-readable storage medium contains computer-readable program codes for converting point cloud data into two-dimensional images, and/or computer-readable program codes for three-dimensional reconstruction of point cloud data, and the like.

It should be understood that various parts of this application may be implemented in hardware, software, firmware, or a combination thereof. In the above-described embodiments, various steps or methods may be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware as in another embodiment, it can be implemented by any one of the following techniques known in the art, or a combination thereof: discrete with logic gates for implementing logic functions on data signals Logic circuits, application-specific integrated circuits with suitable combinational logic gate circuits, Programmable Gate Array (hereinafter referred to as: PGA), Field Programmable Gate Array (Field Programmable Gate Array; referred to as: FPGA), etc.

Although example embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above-described example embodiments are exemplary only, and are not intended to limit the scope of the invention thereto. Various changes and modifications can be made therein by those of ordinary skill in the art without departing from the scope and spirit of the invention. All such changes and modifications are intended to be included within the scope of the invention as claimed in the appended claims.

Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Skilled artisans may implement the described functionality using different methods for each particular application, but such implementations should not be considered beyond the scope of the present invention.

In the several embodiments provided in this application, it should be understood that the disclosed apparatus and method may be implemented in other manners. For example, the device embodiments described above are only illustrative. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components may be combined or May be integrated into another device, or some features may be omitted, or not implemented.

In the description provided herein, numerous specific details are set forth. It will be 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 is to be understood that in the description of the exemplary embodiments of the invention, various features of the invention are sometimes grouped together , or in its description. However, this method of the invention should not be interpreted as reflecting the intention that the invention as claimed requires more features than are expressly recited in each claim. Rather, as the corresponding claims reflect, the invention lies in the fact that the corresponding technical problem may be solved with 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 features disclosed in this specification (including the accompanying claims, abstract and drawings) and any method or apparatus so disclosed may be used in any combination, except that the features are mutually exclusive. Processes or units are combined. Each feature disclosed in this specification (including 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 although some of the embodiments described herein include certain features, but not others, included in other embodiments, that combinations of features of different embodiments are intended to be within the scope of the invention within and form different embodiments. For example, in the claims, any of the claimed embodiments may be used in any combination.

Various component embodiments of the present 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 should understand that a microprocessor or a digital signal processor (DSP) may be used in practice to implement some or all of the functions of some modules according to the embodiments of the present invention. The present invention may also be implemented as apparatus programs (eg, computer programs and computer program products) for performing part or all of the methods described herein. Such a program implementing the present invention may be stored on a computer-readable medium, or may be in the form of one or more signals. Such signals may be downloaded from Internet sites, or provided on carrier signals, or in any other form.

It should be noted that the above-described embodiments illustrate rather than limit the invention, and that alternative embodiments may be devised by those skilled in the art 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 can be implemented by means of hardware comprising several different elements and by means of a suitably programmed computer. In a unit claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The use of the words first, second, and third, etc. do not denote any order. These words can be interpreted as names.

Claims

A distance measuring device, comprising:

The transmitting module is used to transmit the light pulse sequence;

a scanning module, the scanning module includes a rotating first optical element and a rotating second optical element, and is used to sequentially change the light pulse sequence to different propagation directions for output to form a scanning field of view;

a control module, configured to control the ratio of the rotation speed of the first optical element to the first parameter to be a first integer, and to control the ratio of the rotation speed of the second optical element to the first parameter to be a second integer, In order to control the formation of the scanning field of view with the first scanning pattern, or for controlling the ratio of the rotation speed of the first optical element to the second parameter to be a third integer, and to control the rotation speed of the second optical element and The ratio of the second parameter is a fourth integer to control the formation of the scanning field of view with the second scanning pattern, wherein the first parameter includes a ratio of 60 to the integration time, and the second parameter includes 30 to the integration time ratio.
The distance measuring device according to claim 1, wherein the control module is further used for:

Based on user instructions, one of the first parameter and the second parameter is selected.
The distance measuring device according to claim 1, wherein the control module is further used for:

The angle difference between the first optical element and the second optical element is controlled so that the starting point of the scanning track corresponding to the starting point of each integration time is located at the center or edge of the second scanning pattern.
The distance measuring device according to claim 3, wherein when the angle difference between the first optical element and the second optical element is 0° or 360°, the starting point of the scanning track is located at the The edge of the second scanning pattern, when the angle difference between the first optical element and the second optical element is 180°, the starting point of the scanning track is located at the center of the second scanning pattern.
The distance measuring device according to claim 1, wherein the control module is further configured to: control the difference between the third integer and the fourth integer to be 1.
The distance measuring device according to claim 1, wherein the control module is further configured to: control the difference between the first integer and the second integer to be 1.
The distance measuring device according to claim 1, wherein the difference between the first integer and the second integer is a first difference, and the difference between the first integer and the second integer is a first difference The second difference value, when the second difference value is greater than the first difference value, the coverage rate of the scanning track corresponding to the second difference value in the scanning field of view is smaller than that corresponding to the first difference value The coverage of the scan trajectory in the scan field of view.
The distance measuring device according to any one of claims 1 to 7, wherein the scanning trajectory of the scanning points in the first scanning pattern is substantially a spiral, and the scanning trajectory of the scanning points in the second scanning pattern is substantially for the spiral.
The distance measuring device according to any one of claims 1 to 8, wherein the scanning track in the second scanning pattern takes the center of the scanning field of view as the starting point and the edge of the scanning field of view as the end point, or, The scanning track in the second scanning pattern starts from the edge of the scanning field of view and ends at the center of the scanning field of view.
The distance measuring device according to any one of claims 1 to 9, wherein the start point and the end point of the scanning track in the first scanning pattern are located at the same position in the scanning field of view.
The distance measuring device according to any one of claims 1 to 10, wherein the rotation directions of the first optical element and the second optical element are the same, or the first optical element and the second optical element have the same rotation direction. The rotation directions of the two optical elements are different.
The distance measuring device according to any one of claims 1 to 11, wherein the scanning module further comprises a driver, and the control module is configured to control the driver to drive the first optical element and the second optical element Optics rotate.
The distance measuring device according to any one of claims 1 to 12, wherein the first optical element is a prism, and the second optical element is a prism.
The distance measuring device according to any one of claims 1 to 13, wherein the distance measuring device further comprises:

The detection module is configured to receive the light pulse sequence reflected back by the object, and determine the distance and/or orientation of the object relative to the ranging device according to the reflected light pulse sequence.
A control method for scanning a field of view, characterized in that the method comprises:

transmit a sequence of optical pulses;

The ratio of the rotation speed of the first optical element to the first parameter is controlled to be a first integer, and the ratio of the rotation speed of the second optical element to the first parameter is controlled to be a second integer, so as to sequentially change the optical pulse sequence Exiting to different propagation directions to form a scanning field of view with a first scanning pattern, or, controlling the ratio of the rotation speed of the first optical element to the second parameter to be a third integer, and controlling the rotation of the second optical element The ratio of the speed to the second parameter is a fourth integer, so as to sequentially change the light pulse sequence to different propagation directions to form a scanning field of view with a first scanning pattern, wherein the first parameter includes 60 and 60 The ratio of the integration time, the second parameter includes the ratio of 30 to the integration time.
The control method of claim 15, wherein before transmitting the optical pulse sequence, the control method further comprises: selecting one of the first parameter and the second parameter based on a user instruction.
The control method according to claim 15, wherein the control method further comprises: controlling the angle difference between the first optical element and the second optical element, so that the starting points of each integration time correspond to The starting point of the scanning track is located at the center or edge of the second scanning pattern.
The control method according to claim 17, wherein when the angle difference between the first optical element and the second optical element is 0° or 360°, the starting point of the scanning track is located at the At the edge of the second scanning pattern, when the angle difference between the first optical element and the second optical element is 180°, the starting point of the scanning track is located at the center of the second scanning pattern.
The control method according to claim 15, wherein the control method further comprises: controlling the difference between the third integer and the fourth integer to be 1.
The control method according to claim 15, wherein the control method further comprises: controlling the difference between the first integer and the second integer to be 1.
The control method according to claim 15, wherein the difference between the first integer and the second integer is a first difference, and the difference between the first integer and the second integer is a third Two difference values, when the second difference value is greater than the first difference value, the coverage rate of the scanning track corresponding to the second difference value in the scanning field of view is smaller than that corresponding to the first difference value The coverage of the scan trajectory in the scan field of view.
The control method according to any one of claims 15 to 21, wherein the scanning trajectory of the scanning points in the first scanning pattern is generally a spiral, and the scanning trajectory of the scanning points in the second scanning pattern is generally Helix.
The control method according to any one of claims 15 to 22, wherein the scanning track in the second scanning pattern starts from the center of the scanning field of view and ends at the edge of the scanning field of view, or, the The scanning track in the second scanning pattern starts from the edge of the scanning field of view and ends at the center of the scanning field of view.
The control method according to any one of claims 15 to 23, wherein the start point and the end point of the scanning track in the first scanning pattern are located at the same position in the scanning field of view.
The control method according to any one of claims 15 to 24, wherein the rotation directions of the first optical element and the second optical element are the same, or, the first optical element and the second optical element have the same rotation direction The direction of rotation of the optics is different.
The control method according to any one of claims 15 to 25, wherein the first optical element is a prism, and the second optical element is a prism.
The control method according to any one of claims 15 to 26, wherein the control method further comprises:

A sequence of light pulses reflected back by an object is received, and a distance and/or orientation of the object relative to the control method is determined based on the sequence of reflected light pulses.
A movable platform, characterized in that, comprising:

Movable platform body;

The distance measuring device according to any one of claims 1 to 14, which is provided on the movable platform body.
30. The movable platform of claim 28, wherein the movable platform comprises an aircraft, a vehicle, a ship, or a robot.