WO2020154980A1

WO2020154980A1 - Method for calibrating external parameters of detection device, data processing device and detection system

Info

Publication number: WO2020154980A1
Application number: PCT/CN2019/073990
Authority: WO
Inventors: 陈涵; 邢万里; 吴特思
Original assignee: 深圳市大疆创新科技有限公司
Priority date: 2019-01-30
Filing date: 2019-01-30
Publication date: 2020-08-06
Also published as: CN111771140A

Abstract

A method for calibrating external parameters of a detection device, a data processing device and a detection system. Said method is suitable for calibrating external parameters between a first detection device (60) and a second detection device (70). View areas of the first detection device (60) and the second detection device (70) do not overlap each other. The view area of the first detection device (60) after N movements overlaps with the view area of the second detection device (70) in initial state, N being greater than or equal to 1. The method comprises: calculating a first offset parameter between coordinate systems of the first detection device (60) before and after each movement (S101); calculating a second offset parameter between the coordinate system of the first detection device (60) after N movements and the coordinate system of the second detection device (70) in the initial state (S102); and calculating external parameters between the first detection device (60) and the second detection device (70) according to the first offset parameter and the second offset parameter (S103). Hence, the efficiency in calibrating the external parameters of the detection devices may be improved.

Description

Method for calibrating external parameters of detection device, data processing device and detection system

Technical field

The invention relates to data processing technology, in particular to a method for calibrating external parameters of a detection device, a data processing device and a detection system.

Background technique

Detection devices such as lidar can emit detection signals in different directions, and obtain depth information and reflectivity information of objects based on echoes in different directions. When multiple lidars are installed on the same device, in order to fuse the data collected by different lidars into the same coordinate system, it is necessary to calibrate the external parameters of the lidar. In related technologies, for lidars with no overlapping visible areas, the external parameter calibration method adopted includes indirect calibration by additionally setting a camera. In this way, the calibration process is complicated and the efficiency is low.

Summary of the invention

The embodiment of the present invention provides a method, a data processing device and a calibration system for a detection device parameter calibration, so as to calibrate the external parameters of the detection device with no overlap in the visible area, and improve the efficiency of the external parameter calibration.

In the first aspect, an embodiment of the present invention provides a method for calibrating external parameters of a detection device, which is suitable for calibrating external parameters between a first detection device and a second detection device. The first detection device and the second detection device are The visible areas of the devices do not overlap each other, the visible area of the first detection device after N moves and the visible area of the second detection device in the initial state overlap, and the N is greater than or equal to 1, and the method includes :

Calculating the first offset parameter between the coordinate systems before and after each movement of the first detection device;

Calculating a second offset parameter between the coordinate system of the first detection device after N moves and the coordinate system of the second detection device in the initial state;

Calculating an external parameter between the first detection device and the second detection device according to the first offset parameter and the second offset parameter.

In a second aspect, an embodiment of the present invention provides a detection data processing device, which includes at least a memory and a processor; the memory is connected to the processor through a communication bus, and is used to store computer instructions executable by the processor; The processor is used to read computer instructions from the memory to realize:

Calculate the external parameters between the first detection device and the second detection device according to the first offset parameter and the second offset parameter; the difference between the first detection device and the second detection device The visible areas do not overlap each other, the visible area of the first detection device after N moves and the visible area of the second detection device in the initial state overlap, and the N is greater than or equal to 1.

In a third aspect, an embodiment of the present invention provides a detection system, including: a plurality of detection devices and the data processing device of the second aspect, the plurality of detection devices include a first detection device and a second detection device; A plurality of detection devices are installed on the same carrier, and the carrier includes a movable platform through which the detection device is driven to move.

It can be seen from the above technical solution that, in this embodiment, when calibrating the external parameters between the first detection device and the second detection device that do not overlap the visible areas, the first detection device is moved after N times. The visible area overlaps with the visible area of the second detection device in the initial state, calculate the first offset parameter between the coordinate systems before and after the movement of the first detection device, and calculate the first detection device after N moves The second offset parameter between the coordinate system of the first detection device and the coordinate system of the second detection device in the initial state, and then the first detection device and the second detection device are calculated according to the first offset parameter and the second offset parameter This method can calibrate the external parameters of the detection device with no overlap in the visible area, and improve the efficiency of external parameter calibration.

Description of the drawings

In order to explain the technical solutions in the embodiments of the present invention more clearly, the following will briefly introduce 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 may be obtained based on these drawings without creative labor.

Figure 1 is a block diagram of a detection device provided by an embodiment of the present invention;

2 is a schematic structural diagram of a detection device using a coaxial optical path provided by an embodiment of the present invention;

FIG. 3 is a schematic flowchart of a method for calibrating parameters of a detection device according to an embodiment of the present invention;

FIG. 4 is a schematic flowchart of calculating a first offset parameter according to an embodiment of the present invention;

FIG. 5 is a schematic flowchart of calculating a second offset parameter according to an embodiment of the present invention;

6 is a schematic diagram of the relative positions of the first detection device and the second detection device provided by an embodiment of the present invention;

FIG. 7 is a schematic diagram of the relative positions of the first detection device and the second detection device according to an embodiment of the present invention;

FIG. 8 is a schematic structural diagram of a data processing device provided by an embodiment of the present invention;

Fig. 9 is a schematic structural diagram of a detection system provided by an embodiment of the present invention.

detailed description

The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

For this reason, the embodiment of the present invention provides a method for calibrating the external parameters of the detection device, which is suitable for calibrating the external parameters between the detection devices (such as lidar) with non-overlapping visible areas.

In one embodiment, the aforementioned detection device is used to sense external environmental information, for example, distance information, orientation information, reflection intensity information, speed information, etc. of environmental targets. In one implementation, the detection device can detect the distance between the detection device and the detection device by measuring the time of light propagation between the detection device and the detection object, that is, the time-of-flight (TOF). Alternatively, the detection device can also use other technologies to detect the distance from the detection device to the detection device, such as a ranging method based on phase shift measurement, or a ranging method based on frequency shift measurement. Do restrictions.

For ease of understanding, FIG. 1 is a block diagram of a detection device provided by an embodiment of the present invention. The working process of ranging will be described below with reference to the detection device 100 shown in FIG. 1 as an example.

1, the detection device 100 may include a transmitting circuit 110, a receiving circuit 120, a sampling circuit 130, and an arithmetic circuit 140.

The transmitting circuit 110 may emit a light pulse sequence (for example, a laser pulse sequence). The receiving circuit 120 can receive the light pulse sequence (also called an echo signal) reflected by the detected object, and perform photoelectric conversion on the light pulse sequence to obtain an electrical signal. After processing the electrical signal, it can be output to Sampling circuit 130. The sampling circuit 130 may sample the electrical signal to obtain the sampling result. The arithmetic circuit 140 may determine the distance between the detection device 100 and the detected object based on the sampling result of the sampling circuit 130.

Optionally, the detection device 100 may further include a control circuit 150, which can control other circuits, for example, can control the working time of each circuit and/or set parameters for each circuit.

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

In some embodiments, in addition to the circuit shown in FIG. 1, the detection device 100 may further include a scanning module 160 for changing the propagation direction of at least one laser pulse sequence emitted by the transmitting circuit.

Among them, the module including the transmitting circuit 110, the receiving circuit 120, the sampling circuit 130, and the arithmetic circuit 140, or the module including the transmitting circuit 110, the receiving circuit 120, the sampling circuit 130, the arithmetic circuit 140, and the control circuit 150 may be referred to as the tester. The distance measurement module 150 can be independent of other modules, for example, the scanning module 160.

The detection device can adopt a coaxial optical path, that is, the light beam emitted by the detection device and the reflected light beam share at least part of the optical path in the detection device. For example, after at least one laser pulse sequence emitted by the transmitter circuit changes its propagation direction and exits through the scanning module, the laser pulse sequence reflected by the probe passes through the scanning module and then enters the receiving circuit. Alternatively, the detection device may also adopt an off-axis optical path, that is, the light beam emitted by the detection device and the reflected light beam are respectively transmitted along different optical paths in the detection device. Fig. 2 shows a schematic diagram of an embodiment in which the detection device of the present invention adopts a coaxial optical path.

The detection device 200 includes a ranging module 210. The ranging module 210 includes a transmitter 203 (which may include the above-mentioned transmitting circuit), a collimating element 204, a detector 205 (which may include the above-mentioned receiving circuit, sampling circuit, and arithmetic circuit), and an optical path. Change element 206. The ranging module 210 is used to emit a light beam, receive the return light, and convert the return light into an electrical signal. Among them, the transmitter 203 can be used to emit a light pulse sequence. 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 arranged on the exit light path of the emitter, and is used to collimate the light beam emitted from the emitter 203, and collimate the light beam emitted from the emitter 203 into parallel light and output to the scanning module. The collimating element is also used to condense at least a part 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 light path changing element 206 is used to combine the transmitting light path and the receiving light path in the detection device before the collimating element 204, so that the transmitting light path and the receiving light path can share the same collimating element, making the light path more compact. In some other implementation manners, the transmitter 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 light beam emitted by the transmitter 203 is small, and the beam aperture of the return light received by the detection device is relatively large, the light path changing element can use a small-area mirror to transmit The light path and the receiving light path are combined. In some other implementation manners, the optical path changing element may also use a reflector with a through hole, where the through hole is used to transmit the emitted light of the emitter 203 and the reflector is used to reflect the returned light to the detector 205. In this way, the shielding of the back light by the bracket of the small mirror in the case of using the small mirror can be reduced.

In the embodiment shown in FIG. 2, the optical path changing element deviates from the optical axis of the collimating element 204. In some other implementation manners, the optical path changing element may also be located on the optical axis of the collimating element 204.

The detection device 200 further includes a scanning module 202. The scanning module 202 is placed on the exit light path of the distance measuring module 210. The scanning module 202 is used to change the transmission direction of the collimated light 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 collected on the detector 205 via the collimating element 204.

In an embodiment, the scanning module 202 may include at least one optical element for changing the propagation path of the light beam, wherein the optical element may change the propagation path of the light beam by reflecting, refracting, or diffracting the light beam. 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 foregoing optical elements. In an example, at least part of the optical elements are moving. For example, a driving module is used to drive the at least part of the optical elements to move. 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 rotate or vibrate around a common axis 209, and each rotating or vibrating optical element is used to continuously change the propagation direction of the incident light beam. In one embodiment, the multiple optical elements of the scanning module 202 may rotate at different speeds or vibrate at different speeds. In another embodiment, at least part of the optical elements of the scanning module 202 may rotate at substantially the same rotation speed. In some embodiments, the multiple optical elements of the scanning module may also be rotated around 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 vibrate in the same direction, or vibrate in different directions, which is 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. The driver 216 is used to drive the first optical element 214 to rotate around the rotation axis 209 to change the first optical element 214. The direction of the beam 219 is collimated. The first optical element 214 projects the collimated beam 219 to 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 109 changes with the rotation of the first optical element 214. In one embodiment, the first optical element 214 includes a pair of opposed non-parallel surfaces through which the collimated light beam 219 passes. In one embodiment, the first optical element 214 includes a prism whose thickness varies in at least one radial direction. In one embodiment, the first optical element 214 includes a wedge-angle prism, and the collimated beam 219 is refracted.

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 rotation speed and/or rotation of the first optical element 214 and the second optical element 215 are different, so as to project the collimated light beam 219 to the outside space. Different directions can scan a larger space. 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 can be determined according to the expected scanning area and pattern in actual applications. The

drivers

216 and 217 may include motors or other drivers.

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

In one embodiment, the scanning module 202 further includes a third optical element (not shown) and a driver for driving the third optical element to move. Optionally, the third optical element includes a pair of opposite non-parallel surfaces, and the light beam passes through the pair of surfaces. In one embodiment, the third optical element includes a prism whose thickness varies in at least one radial direction. In one embodiment, the third optical element includes a wedge prism. At least two of the first, second, and third optical elements rotate at different rotation speeds and/or rotation directions.

The rotation of each optical element in the scanning module 202 can project light to different directions, such as

directions

211 and 213, so that the space around the detection device 200 is scanned. When the light 211 projected by the scanning module 202 hits the detection object 201, a part of the light is reflected by the detection object 201 to the detection device 200 in a direction opposite to the projected light 211. The return light 212 reflected by the probe 201 is incident on the collimating element 204 after passing through the scanning module 202.

The detector 205 and the transmitter 203 are placed on the same side of the collimating element 204, 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 antireflection 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 an embodiment, a filter layer is plated on the surface of an element located on the beam propagation path in the detection device, or a filter is provided on the beam propagation path, for transmitting at least the wavelength band of the beam emitted by the transmitter, Reflect other bands to reduce the noise caused by ambient light to the receiver.

In some embodiments, the transmitter 203 may include a laser diode through which nanosecond laser pulses are emitted. Further, the laser pulse receiving time can be determined, for example, the laser pulse receiving time can be determined by detecting the rising edge time and/or the falling edge time of the electrical signal pulse. In this way, the detection device 200 can use the pulse receiving time information and the pulse sending time information to calculate the TOF, so as to determine the distance between the detection object 201 and the detection device 200.

The distance and orientation detected by the detection device 200 can be used for remote sensing, obstacle avoidance, surveying and mapping, modeling, navigation, and the like. In one embodiment, the detection device of the embodiment of the present invention can be applied to a movable platform, and the detection device can be installed on the platform body of the movable platform. A movable platform with a detection device can measure the external environment, for example, measuring the distance between the movable platform and an obstacle for obstacle avoidance and other purposes, and for 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, and a camera. When the detection device is applied to an unmanned aerial vehicle, the platform body is the fuselage of the unmanned aerial vehicle. When the detection device is applied to a car, the platform body is the body of the car. The car can be a self-driving car or a semi-self-driving car, and there is no restriction here. When the detection device is applied to a remote control car, the platform body is the body of the remote control car. When the detection device is applied to a robot, the platform body is a robot. When the detection device is applied to a camera, the platform body is the camera itself.

Fig. 3 is a schematic flowchart of a method for calibrating external parameters of a detection device according to an embodiment of the present invention. The method provided by the embodiment of the present invention is suitable for calibrating the external parameters between two detection devices. Taking the two detection devices as an example: the first detection device and the second detection device, the first detection device and The visible areas of the second detection device do not overlap each other. The visible area of the first detection device after N moves and the visible area of the second detection device in the initial state overlap. The N is greater than or equal to 1, refer to the figure As shown in 3, the method includes the following steps S101-S103:

S101. Calculate a first offset parameter between the coordinate systems before and after each movement of the first detection device.

The above-mentioned first offset parameter is a mutual conversion relationship parameter between the coordinate system before and after the movement of the first detection device, and is used to characterize the relative position relationship before and after the movement of the first detection device.

Taking the above-mentioned first detection device and second detection device as Lidar as an example, Lidar is a perceptual sensor that can obtain three-dimensional information of the scene. The basic principle is to actively emit laser pulse signals to the detected object and receive the reflected laser pulse signals. According to the time difference between the emitted laser pulse signal and the received reflected laser pulse signal and the propagation speed of the laser pulse signal , Calculate the depth information of the measured object; obtain the angle information of the measured object relative to the lidar according to the emission direction of the lidar; combine the aforementioned depth information and angle information to obtain a large number of detection points, the data set of the detection points is called a point cloud Based on the point cloud, the three-dimensional information of the measured object relative to the lidar can be reconstructed.

In an embodiment of the present invention, in the foregoing step S101, the method of calculating the first offset parameter between the coordinate systems before and after each movement of the first detection device includes:

Obtain the point cloud of the visible area of the first detection device before and after each movement respectively, and calculate the first offset parameter according to the obtained point cloud of the visible area before and after each movement; wherein, The visible area of the first detection device before and after each movement has an overlapping area.

In this embodiment, each time the first detection device moves, it is set to satisfy the overlap between the visible area before the movement and the visible area after the movement, and the point cloud of the visible area before and after the movement of the first detection device The satisfied relationship calculates the first offset parameter.

FIG. 4 is a schematic flowchart of calculating a first offset parameter according to an embodiment of the present invention. Referring to FIG. 4, in this embodiment, calculating the first offset parameter according to the acquired point cloud of the visible area before and after each movement includes the following steps S201-S202:

S201: Establish a first coordinate relationship function to be satisfied by the point cloud of the overlapping area of the visible area before and after the movement of the first detection device each time.

In this embodiment, the point cloud includes three-dimensional coordinate data. Since the visible area before the movement of the first detection device and the visible area after the movement of the first detection device overlap during the movement, the visible area before the movement of the first detection device There are at least one set of point clouds in the point cloud of the viewing area and the point cloud of the moving viewing area that correspond to the same point in the actual three-dimensional space. Assuming that the set of point clouds are p _i and q _i , that is, it can be The point cloud p _i of the viewing area and the point cloud q _i of the visual area after moving correspond to the same point in the actual three-dimensional space. Based on this, the first coordinate relationship function is established, and the first coordinate relationship function is as follows:

Wherein, the coefficients of the first coordinate relationship function are a parameter R and a parameter t respectively. The parameter R is the first rotation matrix, and t is the first translation matrix.

S202. Establish a first objective function according to the coefficients of the first coordinate relationship function, and minimize the first objective function through the acquired point cloud of the visible area before and after each movement, and calculate a first rotation matrix And the first translation matrix.

The above-mentioned first objective function established based on the coefficients R and t of the first coordinate relationship function is as follows:

The first objective function is minimized, the parameter R and the parameter t are calculated, and then the first rotation matrix and the first translation matrix are obtained, where n is the total number of point clouds in the visible area obtained before the movement of the first detection device and The total number of point clouds in the visual area after the movement; and the first offset parameter between the coordinate systems before and after each movement of the first detection device obtained in this embodiment includes the first rotation matrix and the first translation matrix.

Optionally, the above-mentioned method of minimizing the first objective function may be implemented using a nonlinear optimization method or a singular value decomposition (SVD) method.

In an optional embodiment, after the first rotation matrix and the first offset matrix are calculated, the first transfer matrix is obtained according to the first rotation matrix and the first offset matrix, and the obtained first transfer matrix α1 is as follows Formula (3):

Furthermore, the first offset parameter obtained by the method provided in this embodiment may further include: a first transition matrix.

S102: Calculate a second offset parameter between the coordinate system of the first detection device after N moves and the coordinate system of the second detection device in the initial state.

In this embodiment, the foregoing method of calculating the second offset parameter includes:

Obtain the point cloud of the visible area of the first detection device after N movements and the point cloud of the visible area of the second detection device in the initial state, according to the point cloud of the first detection device after N movements The second offset parameter is calculated from the point cloud of the visible area and the point cloud of the visible area of the second detection device in the initial state.

FIG. 5 is a schematic flowchart of calculating a second offset parameter according to an embodiment of the present invention. Referring to FIG. 5, in the embodiment of the present invention, the point cloud of the visible area after the first detection device moves N times and the point cloud of the visible area of the second detection device in the initial state are described above. Calculating the second offset parameter includes the following steps S301-S302:

S301: Establish a second coordinate relationship function to be satisfied by the point cloud of the overlapping area of the visible area of the first detection device after N moves and the visible area of the second detection device in the initial state.

In this embodiment, the visible area of the first detecting device after N moves and the visible area of the second detecting device in the initial state have an overlapping area, so the visible area of the first detecting device after N moves cloud point and the second detection means has at least one set point cloud corresponding to the actual three-dimensional space with the point, assuming the set point cloud X _i and Y _i in the visible region of the cloud point in an initial state, i.e., a first visual area detecting means after N times after moving cloud X _i and a second detection means cloud point Y _i viewable area in the initial state corresponds to the actual three-dimensional space with the point established based on this second coordinate The relation function is as follows (4),

X _i ＝R ₀ Y _i +t ₀ (4)

Wherein, the coefficients of the above-mentioned second coordinate relationship function are the parameter R ₀ and the parameter t ₀ , the parameter R ₀ is the second rotation matrix, and the parameter t ₀ is the second translation matrix.

S302. Establish a second objective function according to the coefficients of the second coordinate relationship function, and obtain the point cloud of the visible area of the first detection device after N moves and the second detection device in the initial state The point cloud of the visible area minimizes the second objective function, and the second rotation matrix and the second translation matrix are calculated.

The above-mentioned second objective function established based on the coefficients R ₀ and t ₀ of the second coordinate relation function is as follows:

Minimize the above-mentioned second objective function, calculate the parameter R ₀ and the parameter t ₀ to obtain the second rotation matrix and the second translation matrix, where n is the point of the visible area obtained after the first detection device moves N times The total number of clouds and the acquired total number of point clouds in the visible area of the second detection device in the initial state; furthermore, the second offset parameter obtained in this embodiment includes a second rotation matrix and a second translation matrix.

Optionally, the above-mentioned method of minimizing the second objective function may also be implemented using a nonlinear optimization method or a singular value decomposition (SVD) method.

In an optional embodiment, after the second rotation matrix and the second offset matrix are calculated, the second transfer matrix β0 is obtained according to the second rotation matrix and the second offset matrix, and the second transfer matrix is finally obtained. The matrix β0 is as follows (6),

S103. Calculate an external parameter between the first detection device and the second detection device according to the first offset parameter and the second offset parameter.

In this embodiment, the foregoing calculation of the external parameters between the first detection device and the second detection device according to the first offset parameter and the second offset parameter includes:

Multiply the first offset parameter calculated for each movement of the first detection device, and then multiply it with the second offset parameter to obtain the difference between the first detection device and the second detection device The external parameters.

Wherein, the external parameters between the first detection device and the second detection device characterize the relative positional relationship between the first detection device and the second detection device in space, and are used in subsequent processing operations such as point cloud fusion.

Taking the first offset parameter as the first offset matrix and the second offset parameter as the second offset matrix as an example, when the visible area of the first detection device moves through N times and the initial state of the second detection device The visible area of is overlapped, and a first transfer matrix is calculated for each movement of the first detection device; the visible area of the first detection device after three movements is compared with the visible area of the second detection device in the initial state For example, the visible area of the first detection device in the initial state is A0, the visible area of the first detection device after the first movement is the visible area A1, and the visible area of the first detection device after the second movement The visible area is the visible area A2, the visible area of the first detection device after the third movement is the visible area A3, and the visible area of the second detection device in the initial state is the visible area B0. The first transition matrix α1 is calculated from the point cloud of the area A0 and the point cloud of the visible area A1, and the first transition matrix α2 is calculated according to the point cloud of the visible area A1 and the point cloud of the visible area A2, according to the visible area The first transition matrix α3 is calculated from the point cloud of A2 and the point cloud of the visible area A3, and the second transition is calculated according to the point cloud of the visible area A3 and the point cloud of the visible area B0 of the second detection device in the initial state Matrix β0, according to the first transfer matrix and the second transfer matrix obtained by the above calculation, the transfer matrix T between the first detection device and the second detection device is obtained: T=α1·α1·α1·β0.

Optionally, the first detection device and the second detection device mentioned above in the embodiment of the present application start to rotate at the same time around the same central point when they move; this rotation can be realized by a movable platform (such as a car) driving the first detection device With the second detecting device turning or rotating in place, the specific rotation mode is not limited here.

Optionally, the above-mentioned first detection device and the second detection device in the embodiment of the present application translate along the same straight line when moving; the translation may be realized by a movable platform (such as a car) driving the first detection device and the second detection device. The detection device translates along the same straight line.

It should be noted that the movement modes satisfying the overlapping area between the visible area of the first detection device after N movement and the visible area of the second detection device in the initial state are applicable to the present invention, and the present invention does not affect the movement mode. Specific restrictions.

Optionally, when calculating the external parameters between the first detection device and the second detection device according to the overlap between the visible area of the first detection device after N rotations and the visible area of the second detection device in the initial state, When the installation positions of the first detection device and the second detection device are not on the same straight line, the first detection device rotates in a direction close to the second detection device; this way, the number of rotations will be reduced. For example, for the scene shown in FIG. 6, the first detection device 60 and the second detection device 70 are installed on the same straight line. At this time, no matter which direction the first detection device 60 rotates, it will eventually need to rotate through the same angle. After that, the visible area of the first detection device 60 overlaps with the visible area of the second detection device 70 in the initial state. For another example, for the scene shown in FIG. 7, when the first detection device 60 rotates in a direction closer to the second detection device 70 (counterclockwise), the final rotation through an angle will be greater than the direction away from the second detection device. (Clockwise) The angle of rotation is small.

Optionally, the angle between the first detection device 60 and the second detection device 70, the field of view angle of the first detection device 60 and the field of view angle of the second detection device 70 can be preliminarily determined before the rotation. Under the condition that the visible area before and after each rotation of a detection device 60 has overlapping areas, determine the number of rotations required for each rotation of the same angle, and then the first detection device 60 and the second detection device 70 rotate according to the number of rotations .

Fig. 8 is a schematic diagram of a data processing device provided by an embodiment of the present invention. Referring to FIG. 8, the data processing device 1000 includes at least a memory 1002 and a processor 1001; the memory 1002 is connected to the processor 1001 through a communication bus 1003, and is used to store computer instructions executable by the processor 1001; The processor 1001 is configured to read computer instructions from the memory 1001 to implement the method for calibrating the external parameters of the detection device, and is suitable for calibrating the external parameters between the first detection device and the second detection device. The visible area of the device and the second detection device do not overlap each other, the visible area of the first detection device after N moves and the visible area of the second detection device in the initial state overlap, the N Greater than or equal to 1, the method includes:

Optionally, the processor 1001 is further configured to read computer instructions from the memory 1002 to implement:

Establishing a first coordinate relationship function to be satisfied by the point cloud of the overlapping area of the visible area before the movement of the first detection device and the visible area after the movement;

A first objective function is established according to the coefficients of the first coordinate relationship function, and the first objective function is minimized by obtaining the point cloud of the visible area before and after each movement, and the first rotation matrix and the first rotation matrix are calculated. A translation matrix.

The first transfer matrix is calculated according to the first rotation matrix and the first translation matrix.

Obtain the point cloud of the visible area of the first detection device after N moves and the point cloud of the visible area of the second detection device in the initial state, according to the point cloud of the first detection device after N moves The second offset parameter is calculated from the point cloud of the visible area and the point cloud of the visible area of the second detection device in the initial state.

Establishing a second coordinate relationship function to be satisfied by the point cloud of the overlapping area of the visible area of the first detection device after N moves and the visible area of the second detection device in the initial state;

A second objective function is established according to the coefficients of the second coordinate relationship function, and the obtained point cloud of the visible area of the first detection device after N moves and the initial state of the second detection device The point cloud of the viewing area minimizes the second objective function, and the second rotation matrix and the second translation matrix are calculated.

The second transfer matrix is calculated according to the second rotation matrix and the second translation matrix.

Optionally, the first detection device and the second detection device simultaneously start to rotate around the same center point.

Optionally, the first detection device rotates in a direction approaching the second detection device.

According to the external parameters between the first detection device and the second detection device, and the external parameters between the second detection device and other detectors, calculate the first detection device and the other detectors The external parameters between.

Optionally, both the first detection device and the second detection device include at least one of the following: lidar, millimeter wave radar, and ultrasonic radar.

Optionally, the aforementioned data processing device is a host computer.

Optionally, the aforementioned data processing device is provided in the detection device.

The embodiment of the present invention also provides a detection system. As shown in FIG. 9, it includes a plurality of detection devices and the above-mentioned data processing device 1000, and the plurality of detection devices includes a first detection device 60 and a second detection device 70 ( Only two detection devices are shown in the figure); the multiple detection devices are mounted on the same carrier (not shown in the figure), and the carrier includes: a movable platform through which the detection device is driven The device moves.

Optionally, the above-mentioned movable platform includes any one of a vehicle, an aircraft, and a turntable. The above-mentioned turntable may be installed on a vehicle or an aircraft, and the rotation of the turntable drives the rotation of the detection device for external parameter calibration.

As for the device embodiment, since it basically corresponds to the method embodiment, the relevant part can refer to the part of the description of the method embodiment. The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components displayed as units may or may not be physical units, that is, they may be located in One place, or it can be distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the objectives of the solutions of the embodiments. Those of ordinary skill in the art can understand and implement it without creative work.

It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply one of these entities or operations. There is any such actual relationship or order between. The terms "include", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device including a series of elements includes not only those elements, but also other elements not explicitly listed Elements, or also include elements inherent to such processes, methods, articles, or equipment. If there are no more restrictions, the element defined by the sentence "including a..." does not exclude the existence of other same elements in the process, method, article, or equipment that includes the element.

The methods and devices provided by the embodiments of the present invention are described in detail above. Specific examples are used in this article to illustrate the principles and implementations of the present invention. The descriptions of the above embodiments are only used to help understand the methods and methods of the present invention. Core idea; At the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation and scope of application. In summary, the content of this specification should not be construed as limiting the present invention .

Claims

A method for calibrating external parameters of a detection device, characterized in that it is suitable for calibrating external parameters between a first detection device and a second detection device, and the visible area of the first detection device and the second detection device Do not overlap each other, the visible area of the first detection device after N moves and the visible area of the second detection device in the initial state overlap, and the N is greater than or equal to 1. The method includes:

Calculating the first offset parameter between the coordinate systems before and after each movement of the first detection device;

Calculating a second offset parameter between the coordinate system of the first detection device after N moves and the coordinate system of the second detection device in the initial state;

Calculating an external parameter between the first detection device and the second detection device according to the first offset parameter and the second offset parameter.
The method according to claim 1, wherein the calculating the first offset parameter between the coordinate systems before and after each movement of the first detection device comprises:

Obtain the point cloud of the visible area of the first detection device before and after each movement respectively, and calculate the first offset parameter according to the obtained point cloud of the visible area before and after each movement; wherein, The visible area of the first detection device before and after each movement has an overlapping area.
The method according to claim 2, wherein the calculating the first offset parameter according to the acquired point cloud of the visible area before and after each movement comprises:

Establishing a first coordinate relationship function to be satisfied by the point cloud of the overlapping area of the visible area before the movement of the first detection device and the visible area after the movement;

A first objective function is established according to the coefficients of the first coordinate relationship function, and the first objective function is minimized by obtaining the point cloud of the visible area before and after each movement, and the first rotation matrix and the first rotation matrix are calculated. A translation matrix.
The method according to claim 3, wherein after the first transition matrix and the first translation matrix are obtained by the calculation, the method further comprises:

The first transfer matrix is calculated according to the first rotation matrix and the first translation matrix.
The method according to claim 1, wherein the calculating the second deviation between the coordinate system of the first detection device after N moves and the coordinate system of the second detection device in the initial state Shift parameters, including:

Obtain the point cloud of the visible area of the first detection device after N moves and the point cloud of the visible area of the second detection device in the initial state, according to the point cloud of the first detection device after N moves The second offset parameter is calculated from the point cloud of the visible area and the point cloud of the visible area of the second detection device in the initial state.
The method according to claim 5, wherein the point cloud according to the visible area of the first detection device after N moves and the comparison of the visible area of the second detection device in the initial state Point cloud calculation of the second offset parameter includes:

Establishing a second coordinate relationship function to be satisfied by the point cloud of the overlapping area of the visible area of the first detection device after N moves and the visible area of the second detection device in the initial state;

A second objective function is established according to the coefficients of the second coordinate relationship function, and the obtained point cloud of the visible area of the first detection device after N moves and the initial state of the second detection device The point cloud of the viewing area minimizes the second objective function, and the second rotation matrix and the second translation matrix are calculated.
The method according to claim 5, characterized in that, after the second rotation matrix and the second translation matrix are obtained by the calculation, the method further comprises:

The second transfer matrix is calculated according to the second rotation matrix and the second translation matrix.
The method according to claim 1, wherein the calculating an external parameter between the first detection device and the second detection device according to the first offset parameter and the second offset parameter comprises :

Multiply the first offset parameter calculated for each movement of the first detection device, and then multiply it with the second offset parameter to obtain the difference between the first detection device and the second detection device The external parameters.
The method according to claim 1, wherein the first detection device and the second detection device simultaneously start to rotate around the same center point.
The method according to claim 1, wherein the first detection device rotates toward the second detection device.
The method according to claim 1, further comprising:

According to the external parameters between the first detection device and the second detection device, and the external parameters between the second detection device and other detection devices, calculate the first detection device and the other detection devices The external parameters between.
A data processing device, characterized in that it includes at least a memory and a processor; the memory is connected to the processor through a communication bus, and is used to store computer instructions executable by the processor; The memory reads computer instructions to implement the method for calibrating the external parameters of the detection device, which is suitable for calibrating the external parameters between the first detection device and the second detection device. The viewing areas do not overlap each other, and the viewing area of the first detection device after N moves is overlapped with the viewing area of the second detection device in the initial state, and the N is greater than or equal to 1. The method includes:

Calculating the first offset parameter between the coordinate systems before and after each movement of the first detection device;

Calculating a second offset parameter between the coordinate system of the first detection device after N moves and the coordinate system of the second detection device in the initial state;

Calculating an external parameter between the first detection device and the second detection device according to the first offset parameter and the second offset parameter.
The device according to claim 12, wherein the processor is further configured to read computer instructions from the memory to implement:

Obtain the point cloud of the visible area of the first detection device before and after each movement respectively, and calculate the first offset parameter according to the obtained point cloud of the visible area before and after each movement; wherein, The visible area of the first detection device before and after each movement has an overlapping area.
The device according to claim 13, wherein the processor is further configured to read computer instructions from the memory to implement:

Establishing a first coordinate relationship function to be satisfied by the point cloud of the overlapping area of the visible area before the movement of the first detection device and the visible area after the movement;

A first objective function is established according to the coefficients of the first coordinate relationship function, the first objective function is minimized, and the first rotation matrix and the first translation matrix are calculated.
The device according to claim 14, wherein the processor is further configured to read computer instructions from the memory to implement:

The first transfer matrix is calculated according to the first rotation matrix and the first translation matrix.
The device according to claim 12, wherein the processor is further configured to read computer instructions from the memory to implement:

Obtain the point cloud of the visible area of the first detection device after N moves and the point cloud of the visible area of the second detection device in the initial state, according to the point cloud of the first detection device after N moves The second offset parameter is calculated from the point cloud of the visible area and the point cloud of the visible area of the second detection device in the initial state.
The device according to claim 16, wherein the processor is further configured to read computer instructions from the memory to implement:

Establishing a second coordinate relationship function to be satisfied by the point cloud of the overlapping area of the visible area of the first detection device after N moves and the visible area of the second detection device in the initial state;

A second objective function is established according to the coefficients of the second coordinate relationship function, the second objective function is minimized, and a second rotation matrix and a second translation matrix are calculated.
The device according to claim 16, wherein the processor is further configured to read computer instructions from the memory to implement:

The second transfer matrix is calculated according to the second rotation matrix and the second translation matrix.
The device according to claim 12, wherein the processor is further configured to read computer instructions from the memory to implement:

Multiply the first offset parameter calculated for each movement of the first detection device, and then multiply it with the second offset parameter to obtain the difference between the first detection device and the second detection device The external parameters.
The device according to claim 12, wherein the first detection device and the second detection device simultaneously start to rotate around the same center point.
The device according to claim 12, wherein the first detecting device rotates toward the second detecting device.
The device according to claim 12, wherein the processor is further configured to read computer instructions from the memory to implement:

According to the external parameters between the first detection device and the second detection device, and the external parameters between the second detection device and other detectors, calculate the first detection device and the other detectors The external parameters between.
The device according to claim 12, wherein the first detection device and the second detection device both comprise at least one of the following: lidar, millimeter wave radar, and ultrasonic radar.
A detection system, comprising: a plurality of detection devices and the data processing device of any one of claims 12-23, the plurality of detection devices including a first detection device and a second detection device; The two detection devices are installed on the same carrier, and the carrier includes a movable platform through which the detection device is driven to move.
The system according to claim 24, wherein the movable platform comprises any one of a vehicle, an aircraft, and a turntable.