LiDAR scanning beam measurement system

Abstract

The present invention provides a laser radar scanning beam measurement system, comprising a detection device and a data processing device. The detection device includes a detection chip, configured to convert light signals received by the detection chip's photosensitive surface into corresponding voltage signals, and the detection device is movable in a preset direction. The data processing device is configured to, after placing the laser radar under test in a preset posture and aligning the detection surface of the laser radar under test with the detection chip of the detection device, obtain position information of each point of the detection device in the preset direction and a voltage signal corresponding to the position information as a detection signal corresponding to the measured distance when the detection device is moved in a preset direction at a certain measurement distance. The data processing device obtains beam characteristic information of the measured scanning beam in the preset posture based on at least one detection signal corresponding to the measured distance. The present invention enables precise measurement of laser radar scanning beams.

Description

Technical Field

[0001] The present invention relates to the field of laser radar technology, and in particular to a laser radar scanning beam measurement system. Background Art

[0002] As a precision sensing system, lidar has excellent performance such as high ranging accuracy, high angular resolution, and high repetition frequency. It is widely used in intelligent robots, automatic tractors, intelligent / assisted driving, and security.

[0003] The characteristics of the laser radar beam are crucial for achieving high-precision detection. Accurately measuring the energy distribution form and change trend of the laser radar's scanning beam can systematically and quantitatively evaluate the laser radar's performance parameters and the accuracy of the entire machine adjustment.

[0004] Currently, infrared cameras and optical power meters are primarily used to measure laser beams, and these are targeted at fixed-position luminous beams rather than scanning beams. Infrared cameras capture the beam image on a fixed screen, process the intensity information of the beam image, and derive the intensity distribution characteristics of the laser beam. This measurement method requires a very weak background light environment, and the camera must be adjusted to an appropriate focal length and exposure, with a large dynamic range and linear gain to avoid pixel saturation and inaccurate measurement data. Commercial LiDAR systems typically use high-speed rotating beam scanning for target detection. Exposure integration detection of the dynamic scanning beam image at the camera's inherent frame rate can result in significant errors, particularly in its inability to measure the beam intensity distribution in the scanning direction. Optical power meters, on the other hand, require spatial sampling of the beam using a slit to measure the average power over time, making it difficult to accurately measure LiDAR scanning beams.

[0005] Therefore, existing technologies are unable to accurately measure the scanning beam of the lidar. Summary of the Invention

[0006] In view of this, the present invention provides a laser radar scanning beam measurement system, which can solve the problem that the existing technology cannot accurately measure the laser radar scanning beam.

[0007] In a first aspect, an embodiment of the present invention provides a laser radar scanning beam measurement system, the system comprising a detection device and a data processing device;

[0008] The detection device includes a detection chip, and is used to convert the light signal received by the photosensitive surface of the detection chip into a corresponding voltage signal. The detection device can move in a preset direction;

[0009] The data processing device is used to, after placing the laser radar under test in a preset posture and aligning the detection surface of the laser radar under test with the detection chip of the detection device, obtain the position information of each point of the detection device in the preset direction and the voltage signal corresponding to the position information when the detection device is moved along the preset direction at a certain measurement distance, as the detection signal corresponding to the measurement distance, the measurement distance being the vertical distance between the laser radar under test and the preset direction, the preset posture including a first posture or a second posture, in the first posture, the scanning plane of the scanning beam under test of the laser radar under test is perpendicular to the preset direction, and in the second posture, the scanning plane of the scanning beam under test is parallel to the preset direction, and the preset direction is a straight line direction;

[0010] The data processing device obtains the beam characteristic information of the measured scanning light beam in the preset posture according to the detection signal corresponding to at least one measurement distance.

[0011] In a possible implementation, the system further includes an oscilloscope, which is connected to the detection device and the data processing device respectively. The system is further configured to:

[0012] Placing the detection surface of the laser radar under test and the detection chip face to face so that a voltage signal appears on the oscilloscope;

[0013] The position of the laser radar under test is adjusted, or the position of the detection device is adjusted until the voltage signal value on the oscilloscope is maximum.

[0014] In a possible implementation, the system further includes a slide and a radar mounting mechanism, the detection device is mounted on the slide, and the laser radar to be tested is mounted on the radar mounting mechanism;

[0015] Adjusting the height of the slide until the voltage signal value on the oscilloscope reaches a maximum;

[0016] Alternatively, the height of the radar mounting mechanism is adjusted until the voltage signal value on the oscilloscope reaches a maximum.

[0017] In a possible implementation, the data processing device is configured to:

[0018] According to the detection signal corresponding to the first measurement distance, the first position corresponding to the maximum voltage value under the same light spot, the second position corresponding to the voltage value of half the maximum voltage value, and the voltage value of 1 / e of the maximum voltage value are obtained. 2 A third position corresponding to when , wherein one scanning beam generates one light spot;

[0019] Obtaining, according to the first position and the second position, a half-peak width of a spot of the measured scanning light beam at the first measurement distance;

[0020] The beam width of the measured scanning light beam at the first measurement distance is obtained according to the first position and the third position.

[0021] In a possible implementation, the data processing device is configured to:

[0022] The half-peak width of the spot of the measured scanning light beam at the first measurement distance is calculated according to a first formula, and the first formula is:

[0023] W f =2|X m -X f |

[0024] Among them, W f is the half-peak width of the light spot of the measured scanning light speed, X m is the first position, X f For the second position, |X m -X f | is used to indicate the distance between the first position and the second position;

[0025] The beam width of the measured scanning light beam when obtaining the first measurement distance according to the first position and the third position includes:

[0026] The beam width of the measured scanning beam at the first measurement distance is calculated according to a second formula, where the second formula is:

[0027] W e =2|X m -X e |

[0028] Among them, W e is the beam width of the measured scanning light speed, X m is the first position, X e is the third position, |X m -X e | is used to indicate the distance between the first position and the third position.

[0029] In a possible implementation, the data processing device is further configured to:

[0030] Obtaining the half-width at half maximum and the beam width of the measured scanning light beam at a second measurement distance, wherein the second measurement distance is different from the first measurement distance, and the process of obtaining the half-width at half maximum and the beam width of the measured scanning light beam at the second measurement distance is the same as the process of obtaining the half-width at half maximum and the beam width at the first measurement distance;

[0031] Calculating a divergence angle of the measured scanning beam according to the first measurement distance, the second measurement distance, the half-peak width of the spot of the measured scanning beam at the first measurement distance, and the half-peak width of the spot of the measured scanning beam at the second measurement distance;

[0032] Alternatively, the divergence angle of the measured scanning beam is calculated according to the first measurement distance, the second measurement distance, the beam width of the measured scanning beam at the first measurement distance, and the beam width of the measured scanning beam at the second measurement distance.

[0033] In a possible implementation, the data processing device is configured to:

[0034] The divergence angle of the measured scanning light beam is calculated according to the third formula, which is:

[0035]

[0036] Among them, α v is the divergence angle of the measured scanning beam, L is the first measurement distance, L′ is the second measurement distance, and W f is the half-peak width of the spot of the measured scanning beam at the first measurement distance, W f ' is the half-peak width of the spot of the measured scanning beam at the second measurement distance;

[0037] Alternatively, the divergence angle of the measured scanning beam is calculated according to the fourth formula, which is:

[0038]

[0039] Among them, α v , is the divergence angle of the measured scanning beam, L is the first measurement distance, L′ is the second measurement distance, W e is the beam width of the measured scanning beam at the first measurement distance, W e ' is the beam width of the measured scanning light beam at the second measurement distance.

[0040] In a possible implementation, when the laser radar under test is placed in the second posture, the data processing device is further configured to:

[0041] The angular resolution of the measured scanning beam is calculated according to the fifth formula, which is:

[0042]

[0043] Wherein, is the angular resolution of the measured scanning beam, L is the first measurement distance, X2 and X1 are the positions of the maximum voltage values corresponding to two adjacent light spots, respectively, and |X2-X1| is used to represent the distance between the positions of the maximum voltage values of two adjacent light spots.

[0044] In one possible implementation, the laser radar under test is a multi-line laser radar, and the laser radar under test is placed in the first posture, and a plane on which the detection device and the laser radar under test are placed is defined as a placement plane, and the data processing device is further used to:

[0045] When the measurement distance is L, the position X of the maximum voltage value corresponding to the light spots of each two adjacent scanning beams in the same row of multiple scanning beams parallel to the placement plane is obtained. i and X i+1 , where X i is the position of the maximum voltage value corresponding to the spot of the i-th scanning beam, X i+1 is the position of the maximum voltage value corresponding to the light spot of the (i+1)th scanning beam adjacent to the (i)th scanning beam;

[0046] According to the sixth formula, the angle between the i-th scanning beam and the i+1-th scanning beam is obtained: The sixth formula is

[0047]

[0048] Among them, |X i+1 -X i | is used to represent the distance between the positions of the maximum voltage values corresponding to the spots of the i-th scanning beam and the i+1-th scanning beam;

[0049] The spatial distribution information of the scanning beams of the multi-line laser radar is obtained according to the angle between every two adjacent scanning beams in each row of scanning beams and the angle between two adjacent rows of scanning beams.

[0050] In a possible implementation, the data processing device is further configured to:

[0051] According to the detection signal corresponding to the first measurement distance, the fourth position corresponding to the preset voltage value of the voltage value under the same light spot is obtained, and the full width W of the measured scanning light beam at the first measurement distance is obtained according to the first position and the fourth position. o ;

[0052] Change the transmit power of the laser radar under test, obtain the corresponding relationship curve of voltage and spot half-peak width, and obtain the corresponding relationship curve of voltage and beam full width. In the corresponding relationship curve of voltage and spot half-peak width, the horizontal axis is used to represent the maximum voltage value of the spot, and the vertical axis is used to represent the spot half-peak width W corresponding to a maximum voltage value. f In the curve diagram of the corresponding relationship between voltage and full width of the beam, the horizontal axis is used to represent the maximum voltage value of the light spot, and the vertical axis is used to represent the full width of the beam corresponding to a maximum voltage value W. o The value of

[0053] The transmission power range of the laser radar under test is determined based on the corresponding relationship curve diagram between the voltage and the half-peak width of the light spot, and the corresponding relationship curve diagram between the voltage and the full width of the light beam.

[0054] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0055] The embodiment of the present invention directly detects the light beam by utilizing the photosensitive surface of the detection chip of the detection device without a subsequent amplification circuit. The detection device is moved along a preset direction at a fixed measurement distance to obtain the position information of the detection device and the corresponding voltage information to obtain detection data. The detection data is processed to obtain the beam characteristic information of the scanning light beam, thereby realizing accurate measurement of the scanning light beam. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0057] Figure 1 is a schematic diagram of a laser radar scanning beam measurement system provided by an embodiment of the present invention;

[0058] Figure 2 1 is a schematic diagram of the circuit structure of a detection chip provided by an embodiment of the present invention;

[0059] Figure 3 is a schematic diagram of a laser radar under test in a system provided by an embodiment of the present invention placed in a first posture;

[0060] Figure 4 is a schematic diagram of a laser radar under test in a system provided by an embodiment of the present invention being placed in a second posture;

[0061] Figure 5 is a schematic diagram of another laser radar scanning beam measurement system provided by an embodiment of the present invention;

[0062] Figure 6 is a schematic diagram of determining a preset direction origin in an embodiment of the present invention;

[0063] Figure 7a Schematic diagram of the relationship between the beam width and the measurement distance of the single-line laser radar 1;

[0064] Figure 7b Schematic diagram of the relationship between the beam width and the measurement distance of the single-line laser radar 2;

[0065] Figure 8 The graphs are a graph showing the relationship between voltage and spot half-peak width, and a graph showing the relationship between voltage and beam full width, provided in an embodiment of the present invention;

[0066] Figure 9 2 is a schematic diagram of a processing device in a laser radar scanning beam measurement system provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0067] In the following description, specific details such as particular system structures and techniques are provided for purposes of illustration, not limitation, to facilitate a thorough understanding of the embodiments of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.

[0068] In order to make the purpose, technical solutions and advantages of the present invention more clear, specific embodiments will be described below with reference to the accompanying drawings.

[0069] Combine Figure 1 , an embodiment of the present invention provides a laser radar scanning beam measurement system 1, which includes a detection device 11 and a data processing device 12;

[0070] The detection device 11 includes a detection chip, which is used to convert the light signal received by the photosensitive surface of the detection chip into a corresponding voltage signal. The detection device can move in a preset direction;

[0071] The data processing device 12 is used to, after placing the laser radar under test in a preset posture and aligning the detection surface of the laser radar under test with the detection chip of the detection device 11, obtain position information of each point of the detection device 11 in the preset direction and a voltage signal corresponding to the position information when the detection device 11 is moved along a preset direction at a certain measurement distance, as the detection signal corresponding to the measurement distance, where the measurement distance is the perpendicular distance between the laser radar under test and the preset direction, and the preset posture includes a first posture or a second posture. In the first posture, the scanning plane of the scanning beam under test of the laser radar under test is perpendicular to the preset direction, and in the second posture, the scanning plane of the scanning beam under test is parallel to the preset direction, and the preset direction is a straight line direction;

[0072] The data processing device 12 obtains beam characteristic information of the measured scanning beam in a preset posture according to a detection signal corresponding to at least one measurement distance.

[0073] Among them, the circuit structure diagram of the detection chip is as follows Figure 2 shown.

[0074] At present, the intensity distribution characterization of most laser beams is mainly for laser beams with fixed positions, which are achieved by using high-resolution cameras to image and detect the beams, and by using slits or knife edges to block part of the beam for spatial sampling combined with optical power meter measurement. The above schemes all require post-stage circuit amplification for photoelectric conversion. The linear gain, dynamic range and amplification bandwidth of the amplifier circuit are required to be high, and the circuit structure is complex and difficult to debug. When using slits or knife edges to block the laser beam for measurement, it is impossible to avoid the diffraction effect of the beam transmission affecting the detection accuracy, and the slit or knife edge method requires high installation position and adjustment accuracy, and the measurement process is time-consuming. In addition, the above method is more difficult for the dynamic measurement of the laser radar scanning beam of the whole machine, and the final product form of the laser radar is high-speed rotating beam scanning detection. In addition to determining whether the parameters of the laser radar whole machine have reached the target value, the accurate measurement of the laser radar scanning beam can also evaluate the laser radar optical-mechanical system problems and potential risks.

[0075] See also Figure 2 , the detection chip is in normal detection working state under reverse bias voltage, receives the energy of the overlapping area of the laser spot of the scanning beam and the photosensitive surface, converts the light signal into photocurrent, and then transmits it through the load resistor R L Realize voltage signal conversion. Figure 2The detection chip shown here allows the entire signal detection process to be performed directly on the chip, without subsequent circuit amplification. This results in a simple circuit structure and high system gain linearity. Furthermore, by directly measuring the scanning beam using the detector chip's photosensitive surface, better sampling is achieved than with existing slit-based measurement techniques. The diffraction effect of beam transmission caused by obstructed light is eliminated, resulting in more accurate measurement results. Furthermore, the system requires less precision, simplifying installation and calibration.

[0076] Combine Figure 2 The detection chip can be a PN photodiode (PN PD), a PIN photodiode (PIN PD), or an avalanche photodiode (APD). The power supply is a DC voltage source, and the voltage range applied to the detection chip is the linear voltage operating range of the detection chip.

[0077] Laser radar can be divided into single-line laser radar and multi-line laser radar. Single-line laser radar has only one scanning beam. When the single-line laser radar is placed vertically on a horizontal plane, the scanning beam of the single-line laser radar scans along the horizontal plane. When the single-line laser radar is placed sideways on the horizontal plane, the scanning beam of the single-line laser radar scans along the scanning plane perpendicular to the horizontal plane.

[0078] The multi-line laser radar includes multiple scanning beams, and the scanning method of each scanning beam is the same as the scanning method of the above-mentioned single-line laser radar.

[0079] In the embodiment of the present invention, the plane on which the detection device 11 and the laser radar under test are placed is used as the placement plane. The detection device 11 can move in a preset direction, which is a linear direction. In some embodiments, the detection device 11 can be placed on a linear guide rail and can move along the guide rail. The guide rail represents the preset direction in the embodiment of the present invention.

[0080] When the laser radar under test is placed in the first posture, the scanning plane of the scanning beam is perpendicular to the preset direction, such as Figure 3 As shown in , when the laser radar under test is placed in the second posture, the scanning plane of the scanning beam is parallel to the preset direction, as shown in Figure 4 shown.

[0081] In the embodiment of the present invention, Figure 5 The laser radar scanning beam measurement system further includes an oscilloscope 13, which is connected to the detection device 11 and the data processing device 12, respectively. The oscilloscope 13 can display the voltage signal value output by the detection device 11 in real time. In some embodiments, the detection device 11 is connected to the oscilloscope via a coaxial line. The characteristic impedance of the coaxial line is preferably 50Ω, but may also be 25Ω, 75Ω, or 100Ω, although this is not limited in this embodiment of the present invention.

[0082] When starting the measurement, the detection surface of the laser radar to be measured is placed face to face with the detection chip so that a voltage signal appears on the oscilloscope 13; then the position of the laser radar to be measured is adjusted, or the position of the detection device is adjusted until the voltage signal value on the oscilloscope 13 is the maximum.

[0083] Combine Figure 3 The area of the laser spot of the laser radar scanning beam is large, and the area of the photosensitive surface of the detection device is small. When the photosensitive surface is not within the range of the laser spot, the voltage signal is basically 0. When the photosensitive surface is within the edge range of the laser spot, the voltage signal is small. When the photosensitive surface is in the same horizontal plane as the center of the laser spot and close to the center position, the voltage signal value on the oscilloscope is the largest, indicating that the photosensitive surface and the center of the laser spot are at the same height.

[0084] In some embodiments, the system 1 provided by an embodiment of the present invention also includes a slide 14 and a radar mounting mechanism 15. The detection device 11 is installed on the slide 14, and the laser radar to be tested is installed on the radar mounting mechanism 15. The height of the slide 14 is adjusted until the voltage signal value on the oscilloscope 13 is maximum; or, the height of the radar mounting mechanism 15 is adjusted until the voltage signal value on the oscilloscope 13 is maximum.

[0085] Combine Figure 3 and Figure 4 Keeping the laser radar under test stationary, the detection device 11 is moved in a preset direction. As the relative position of the photosensitive surface and the laser spot changes, the voltage signal output by the detection device 11 also changes. If the measurement distance is fixed, such as L, this step can obtain the detection information corresponding to L.

[0086] In an embodiment of the present invention, the detection device 11 can be mounted on a linear guide rail, along which the detection device 11 can move. The guide rail represents a predetermined direction in the embodiment of the present invention. The guide rail is provided with scale information. When the detection device moves to a certain position on the guide rail, the scale information on the guide rail can be used to represent the position information of the detection device at that time.

[0087] In the embodiment of the present invention, Figure 6 After the laser radar under test is aligned with the detection device, the position of the laser radar under test remains unchanged. The intersection of the laser radar under test and the preset direction, the perpendicular line of the guide rail where the detection device 11 is located, and the preset direction is taken as the origin X0, and the scale value at X0 is 0.

[0088] In some embodiments, the data processing device 12 is configured to:

[0089] According to the detection signal corresponding to the first measurement distance, the first position corresponding to the maximum voltage value under the same light spot, the second position corresponding to half of the maximum voltage value, and the voltage value 1 / e of the maximum voltage value are obtained. 2 The third position corresponding to the time; according to the first position and the second position, the half-peak width of the spot of the measured scanning beam when the first measuring distance is obtained; according to the first position and the third position, the beam width of the measured scanning beam when the first measuring distance is obtained.

[0090] In this process, a scanning beam generates a light spot.

[0091] In a possible implementation, the data processing device 12 calculates the half-peak width of the spot of the measured scanning beam at the first measurement distance according to the first formula. The first formula is:

[0092] W f =2|X m -X f |

[0093] Among them, W f is the half-peak width of the light spot of the measured scanning light speed, X m is the first position, X f For the second position, |X m -X f |Used to indicate the distance between the first position and the second position;

[0094] The beam width of the scanned light beam to be measured when the first measurement distance is obtained according to the first position and the third position includes:

[0095] The beam width of the measured scanning beam at the first measurement distance is calculated according to the second formula. The second formula is:

[0096] W e =2|X m -X e |

[0097] Among them, W e is the beam width of the measured scanning light speed, X m is the first position, X e For the third position, |X m -X e | is used to indicate the distance between the first and third positions.

[0098] In an embodiment of the present invention, the first measuring distance can be represented by L. Through the above measurement process, the half-width at half maximum and the beam width of the spot of the measured scanning beam in a preset posture when the measuring distance is L can be obtained, that is, when the measuring distance is L, the half-width at half maximum and the beam width of the spot of the scanning beam when the measured laser radar is placed in the first posture, and the half-width at half maximum and the beam width of the scanning beam when the measured laser radar is placed in the second posture can be obtained.

[0099] Through the above measurement process, the half-peak width and beam width of the scanning light beam of the laser radar under test when placed in the first posture and the second posture at different distances can be obtained.

[0100] Combine Figure 4 The system provided by the embodiment of the present invention is further used to obtain the divergence angle of the scanning beam. In one possible implementation, the data processing device 12 is further used to:

[0101] Obtaining a half-width (FWHM) and a beam width (BWHM) of the scanned light beam at a second measurement distance, wherein the second measurement distance is different from the first measurement distance, and the process for obtaining the half-width (FWHM) and the beam width (BWHM) of the scanned light beam at the second measurement distance is the same as the process for obtaining the half-width (FWHM) and the beam width (BWHM) of the scanned light beam at the first measurement distance;

[0102] Calculate the divergence angle of the measured scanning beam according to the first measurement distance, the second measurement distance, the half-peak width of the spot of the measured scanning beam at the first measurement distance, and the half-peak width of the spot of the measured scanning beam at the second measurement distance;

[0103] Alternatively, the divergence angle of the measured scanning beam is calculated according to the first measurement distance, the second measurement distance, the beam width of the measured scanning beam at the first measurement distance, and the beam width of the measured scanning beam at the second measurement distance.

[0104] In some embodiments, the data processing device 12 is configured to:

[0105] The divergence angle of the measured scanning beam is calculated according to the third formula. The third preset formula is:

[0106]

[0107] Among them, α v is the divergence angle of the scanned beam to be measured, L is the first measurement distance, L′ is the second measurement distance, and W f is the half-peak width of the scanning beam at the first measurement distance, W f ' is the half-peak width of the spot of the measured scanning beam at the second measuring distance;

[0108] Alternatively, the divergence angle of the scanned light beam to be measured is calculated according to the fourth formula, which is:

[0109]

[0110] Among them, α v is the divergence angle of the scanned beam to be measured, L is the first measurement distance, L′ is the second measurement distance, and W e is the beam width of the scanned beam at the first measurement distance, W e ' is the beam width of the scanned light beam being measured at the second measuring distance.

[0111] When the laser radar under test is placed in the second posture, the data processing device 12 is further used to calculate the angular resolution of the scan beam under test according to the fifth formula. The fifth formula is:

[0112]

[0113] Wherein, is the angular resolution of the measured scanning beam, L is the first measurement distance, X2 and X1 are the positions of the maximum voltage values corresponding to two adjacent light spots, respectively, and |X2-X1| is used to represent the distance between the positions of the maximum voltage values of two adjacent light spots.

[0114] Through the above measurement process, we can obtain the half-peak width, beam width, and divergence angle of the scanning beam when the measured LiDAR is placed in the first posture. We can also obtain the half-peak width, beam width, divergence angle, and angular resolution of the scanning beam when the measured LiDAR is placed in the second posture. These indicators are the beam characteristic indicators of the scanning beam.

[0115] The performance of the laser radar under test can be evaluated based on the beam characteristic information of the scanning beam. In the embodiment of the present invention, the divergence angle when the laser radar under test is placed in the first posture is called the longitudinal divergence angle, and the divergence angle when the laser radar under test is placed in the second posture is called the lateral divergence angle. In one example, combined with Figure 7a and Figure 7b , Figure 7a 7a is the relationship curve between the beam width and the measured distance of the single-line laser radar 1, and 7b is the relationship curve between the beam width and the measured distance of the single-line laser radar 2. The system provided by the embodiment of the present invention is used to measure the beam characteristic information of the scanning beams of the single-line laser radar 1 and the single-line laser radar 2. The detection chip used is an avalanche diode, and its detection photosensitive surface diameter is 500μm. For the centimeter-level beam size, the beam space sampling requirement is met. The longitudinal divergence angle of the single-line laser radar 1 is 5.2mrad, and the lateral divergence angle is 0.8marad. The longitudinal divergence angle of the single-line laser radar 2 is 8.4mrad, and the lateral divergence angle is 4.2mrad. According to the results, the longitudinal divergence angles of the two single-line laser radars are not much different, while the lateral divergence angle of the single-line laser radar 1 is better than that of the single-line laser radar 2. The beam of the single-line laser radar 1 is an elongated ellipse as the transmission distance increases, and its lateral spatial resolution is higher.

[0116] In some embodiments, the tilt angle of the photosensitive surface is changed so that the overlapping area between the photosensitive surface and the laser spot of the scanned light beam being measured is smaller than the actual area of the photosensitive surface, thereby increasing the spatial sampling frequency of the light beam.

[0117] The plane where the detection device 11 and the laser radar to be tested are placed is used as the placement plane, and the axis passing through the photosensitive surface and perpendicular to the placement plane is used as the z-axis. The tilt angle of the photosensitive surface is changed so that the angle between the photosensitive surface and the z-axis is β. If the photosensitive surface is a circular photosensitive surface with a diameter of d, when the chip photosensitive surface is perpendicular to the light beam transmission direction, that is, the photosensitive surface is parallel to the z-axis, then the detection area is the actual area of the photosensitive surface. When the angle between the photosensitive surface and the z-axis is β, the effective detection area of the photosensitive surface is becomes Increased spatial sampling frequency times.

[0118] If the photosensitive surface is a square with a side length of a, then when the chip photosensitive surface is perpendicular to the direction of light beam transmission, that is, the photosensitive surface is parallel to the z-axis, then the detection area is the actual area of the photosensitive surface, which is a. 2 When the angle between the photosensitive surface and the z-axis is β, the effective detection area of the photosensitive surface is a 2 becomes a 2 cosβ, spatial sampling frequency is increased times.

[0119] In some embodiments, detection signals at multiple different measurement distances can be acquired. For the same beam characteristic indicator, the divergence angle of the laser radar under test when placed in a first posture, the detection signals at multiple different measurement distances can be processed using the system provided by an embodiment of the present invention to obtain multiple divergence angle values. The obtained multiple divergence angle values can be processed according to the actual application scenario, such as by averaging the multiple divergence angle values to obtain a single divergence angle value to improve measurement accuracy.

[0120] In some embodiments, if the laser radar under test is a multi-line laser radar and is placed in the first posture, the plane on which the detection device 11 and the laser radar under test are placed is defined as the placement plane, and the data processing device 12 is further used to obtain the spatial distribution information of the scanning beam of the laser radar under test, including:

[0121] When the measured distance is L, combined with Figure 6 , the position of the origin X0 = 0, obtain the position X of the maximum voltage value corresponding to the spots of each two adjacent scanning beams in the same row of multiple scanning beams parallel to the placement plane i and X i+1 , where X iis the position of the maximum voltage value corresponding to the spot of the i-th scanning beam, X i+1 is the position of the maximum voltage value corresponding to the light spot of the (i+1)th scanning beam adjacent to the (i)th scanning beam;

[0122] According to the sixth formula, the angle between the i-th scanning beam and the i+1-th scanning beam is obtained: The sixth formula is

[0123]

[0124] Among them, |X i+1 -X i | is used to represent the distance between the positions of the maximum voltage values corresponding to the spots of the i-th scanning beam and the i+1-th scanning beam;

[0125] The spatial distribution information of the scanning beams of the multi-line laser radar is obtained according to the angle between every two adjacent scanning beams in each row of scanning beams and the angle between two adjacent rows of scanning beams.

[0126] Compared with single-line laser radar, multi-line laser radar has multiple scanning beams, which obtain three-dimensional space point clouds by scanning at different pitch angles and horizontal angles. The scanning trajectory changes in a complex way, and accurately measuring its scanning beam characteristics is conducive to evaluating the performance indicators, installation accuracy and reliability of the laser radar.

[0127] The system provided in the embodiment of the present invention is also used to determine the transmit power of the laser radar being measured. In some embodiments, the data processing device 12 is further used to:

[0128] According to the detection signal corresponding to the first measurement distance, the fourth position corresponding to the preset voltage value under the same light spot is obtained, and the full width W of the measured scanning beam at the first measurement distance is obtained according to the first position and the fourth position. o ;

[0129] Change the transmit power of the laser radar under test, obtain the corresponding relationship curve between voltage and spot half-peak width, and obtain the corresponding relationship curve between voltage and beam full width. In the corresponding relationship curve between voltage and spot half-peak width, the horizontal axis is used to represent the maximum voltage value of the spot, and the vertical axis is used to represent the spot half-peak width W corresponding to a maximum voltage value. f In the curve of the corresponding relationship between voltage and beam full width, the horizontal axis is used to represent the maximum voltage value of the spot, and the vertical axis is used to represent the beam full width W corresponding to a maximum voltage value. o The value of

[0130] The transmission power range of the laser radar under test is determined based on the corresponding relationship curve between voltage and half-peak width of the light spot, as well as the corresponding relationship curve between voltage and full width of the beam.

[0131] Optionally, the preset voltage value is 10mV.

[0132] Figure 8 The graphs show the corresponding relationship between the voltage and the half-peak width of the laser radar under test, as well as the corresponding relationship between the voltage and the full width of the beam. In practical applications, the transmit power of the laser radar under test is as large as possible within a certain range. However, in order to ensure the accuracy of the laser radar measurement, the full width of the scanning beam and the half-peak width of the spot are as small as possible. Figure 8 The half-peak width and full-width of the scanning beam of the laser radar under test change slowly when the voltage value is less than or equal to 600mV, and the rising speed becomes significantly faster when it is greater than 800mV. Therefore, the power range corresponding to 600mV to 800mV can be selected as the transmission power range of the laser radar under test.

[0133] During the above measurement process, the oscilloscope can also directly display the time domain information of the scanning light beam, such as repetition frequency, pulse width, rise time, etc.

[0134] The embodiment of the present invention directly detects the light beam by utilizing the photosensitive surface of the detection chip of the detection device without a subsequent amplification circuit. The detection device is moved along a preset direction at a fixed measurement distance to obtain the position information of the detection device and the corresponding voltage information to obtain detection data. The detection data is processed to obtain the beam characteristic information of the scanning light beam, thereby realizing a precise strategy for the scanning light beam.

[0135] Figure 9 FIG is a schematic diagram of a data processing device 12 provided in one embodiment of the present invention. Figure 9 As shown, the processing device 12 of this embodiment includes: a processor 120 , a memory 121 , and a computer program 122 stored in the memory 121 and executable on the processor 120 .

[0136] Exemplarily, the computer program 122 may be divided into one or more modules / units, which are stored in the memory 121 and executed by the processor 120 to implement the present invention. The one or more modules / units may be a series of computer program instruction segments capable of implementing specific functions, and the instruction segments are used to describe the execution process of the computer program 122 in the processing device 12.

[0137] The processing device 12 may be a computing device such as a desktop computer, a notebook, a PDA, or a cloud server. The processing device 12 may include, but is not limited to, a processor 120 and a memory 121. It will be understood by those skilled in the art that Figure 9This is merely an example of the processing device 12 and does not constitute a limitation on the processing device 12. The processing device 12 may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, the processing device may also include input and output devices, network access devices, buses, etc.

[0138] The processor 120 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor.

[0139] The memory 121 may be an internal storage unit of the processing device 12, such as a hard disk or memory of the processing device 12. The memory 121 may also be an external storage device of the processing device 12, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc. equipped on the processing device 12. Furthermore, the memory 121 may include both an internal storage unit of the processing device 12 and an external storage device. The memory 121 is used to store the computer program and other programs and data required by the processing device. The memory 121 may also be used to temporarily store data that has been output or is about to be output.

[0140] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In actual applications, the above-mentioned functions can be distributed and completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated into one processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned system embodiment, and will not be repeated here.

[0141] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant description of other embodiments.

[0142] Those skilled in the art will appreciate 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. Professionals and technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present invention.

[0143] In the embodiments provided by the present invention, it should be understood that the disclosed devices / processing devices can be implemented in other ways. For example, the device / processing device embodiments described above are merely illustrative. For example, the division of the modules or units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0144] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0145] In addition, the functional units in the various embodiments of the present invention may be integrated into a single processing unit, each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0146] If the integrated module / unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. The computer program includes computer program code, which can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electric carrier signal, telecommunication signal and software distribution medium. It should be noted that the content contained in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electric carrier signals and telecommunication signals.

[0147] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention, and should all be included in the scope of protection of the present invention.

Claims

1. A laser radar scanning beam measurement system, characterized in that: The system includes a detection device and a data processing device; The detection device includes a detection chip, and is used to convert the light signal received by the photosensitive surface of the detection chip into a corresponding voltage signal. The detection device can move in a preset direction; The data processing device is used to, after placing the laser radar under test in a preset posture and aligning the detection surface of the laser radar under test with the detection chip of the detection device, obtain the position information of each point of the detection device in the preset direction and the voltage signal corresponding to the position information when the detection device is moved along the preset direction at a certain measurement distance, as the detection signal corresponding to the measurement distance, the measurement distance being the vertical distance between the laser radar under test and the preset direction, the preset posture including a first posture or a second posture, in the first posture, the scanning plane of the scanning beam under test of the laser radar under test is perpendicular to the preset direction, and in the second posture, the scanning plane of the scanning beam under test is parallel to the preset direction, and the preset direction is a straight line direction; The data processing device obtains beam characteristic information of the measured scanning beam in the preset posture according to a detection signal corresponding to at least one measurement distance; The data processing device is used for: According to the detection signal corresponding to the first measurement distance, the first position corresponding to the maximum voltage value under the same light spot, the second position corresponding to the voltage value of half the maximum voltage value, and the voltage value of 1 / e of the maximum voltage value are obtained. 2 A third position corresponding to when , wherein one scanning beam generates one light spot; Obtaining, according to the first position and the second position, a half-peak width of a spot of the measured scanning light beam at the first measurement distance; The beam width of the measured scanning light beam at the first measurement distance is obtained according to the first position and the third position.

2. The system according to claim 1, wherein: The system further includes an oscilloscope, which is connected to the detection device and the data processing device respectively. The system is further configured to: Placing the detection surface of the laser radar under test and the detection chip face to face so that a voltage signal appears on the oscilloscope; The position of the laser radar under test is adjusted, or the position of the detection device is adjusted until the voltage signal value on the oscilloscope is maximum.

3. The system according to claim 2, characterized in that The system further comprises a slide and a radar mounting mechanism, wherein the detection device is mounted on the slide, and the laser radar to be tested is mounted on the radar mounting mechanism; Adjusting the height of the slide until the voltage signal value on the oscilloscope reaches a maximum; Alternatively, the height of the radar mounting mechanism is adjusted until the voltage signal value on the oscilloscope reaches a maximum.

4. The system according to claim 1, wherein: The data processing device is used for: The half-peak width of the spot of the measured scanning beam at the first measurement distance is calculated according to the first formula. The first formula is W f =2|X m -X f | Among them, W f is the half-peak width of the spot of the measured scanning beam, X m is the first position, X f For the second position, |X m -X f | is used to indicate the distance between the first position and the second position; The beam width of the measured scanning light beam when obtaining the first measurement distance according to the first position and the third position includes: The beam width of the measured scanning beam at the first measurement distance is calculated according to a second formula, where the second formula is: W e =2|X m -X e | Among them, W e is the beam width of the scanned beam under test, X m is the first position, X e is the third position, |X m -X e | is used to indicate the distance between the first position and the third position.

5. The system according to claim 4, characterized in that The data processing device is further configured to: Obtaining the half-width at half maximum and the beam width of the measured scanning light beam at a second measurement distance, wherein the second measurement distance is different from the first measurement distance, and the process of obtaining the half-width at half maximum and the beam width of the measured scanning light beam at the second measurement distance is the same as the process of obtaining the half-width at half maximum and the beam width at the first measurement distance; Calculating a divergence angle of the measured scanning beam according to the first measurement distance, the second measurement distance, the half-peak width of the spot of the measured scanning beam at the first measurement distance, and the half-peak width of the spot of the measured scanning beam at the second measurement distance; Alternatively, the divergence angle of the measured scanning beam is calculated according to the first measurement distance, the second measurement distance, the beam width of the measured scanning beam at the first measurement distance, and the beam width of the measured scanning beam at the second measurement distance.

6. The system according to claim 5, characterized in that The data processing device is used for: The divergence angle of the measured scanning light beam is calculated according to the third formula, which is: Among them, α v is the divergence angle of the measured scanning beam, L is the first measuring distance, and L ′ is the second measured distance, W f is the half-peak width of the spot of the measured scanning beam at the first measurement distance, W f ′ is the half-peak width of the spot of the measured scanning light beam at the second measurement distance; Alternatively, the divergence angle of the measured scanning beam is calculated according to the fourth formula, which is: Among them, α v is the divergence angle of the measured scanning beam, L is the first measuring distance, and L ′ is the second measured distance, W e is the beam width of the measured scanning beam at the first measurement distance, W e ′ is the beam width of the measured scanning beam at the second measurement distance.

7. The system according to any one of claims 1 to 6, characterized in that When the laser radar under test is placed in the second posture, the data processing device is further used to: The angular resolution of the measured scanning beam is calculated according to the fifth formula, which is: Among them, A h is the angular resolution of the measured scanning beam, L is the first measurement distance, X2 and X1 are the positions of the maximum voltage values corresponding to two adjacent light spots, and |X2-X1| is used to represent the distance between the positions of the maximum voltage values of two adjacent light spots.

8. The system according to any one of claims 1 to 6, characterized in that The laser radar under test is a multi-line laser radar, and the laser radar under test is placed in the first posture, and a plane on which the detection device and the laser radar under test are placed is defined as a placement plane, and the data processing device is further used to: When the measurement distance is L, the position X of the maximum voltage value corresponding to the light spots of each two adjacent scanning beams in the same row of multiple scanning beams parallel to the placement plane is obtained. i and X i+1 , where X i is the position of the maximum voltage value corresponding to the spot of the i-th scanning beam, X i+1 is the position of the maximum voltage value corresponding to the light spot of the (i+1)th scanning beam adjacent to the (i)th scanning beam; According to the sixth formula, the angle between the i-th scanning beam and the i+1-th scanning beam is obtained: The sixth formula is Among them, |X i+1 -X i | is used to represent the distance between the positions of the maximum voltage values corresponding to the spots of the i-th scanning beam and the i+1-th scanning beam; The spatial distribution information of the scanning beams of the multi-line laser radar is obtained according to the angle between every two adjacent scanning beams in each row of scanning beams and the angle between two adjacent rows of scanning beams.

9. The system according to claim 4, wherein: The data processing device is further configured to: According to the detection signal corresponding to the first measurement distance, the fourth position corresponding to the preset voltage value of the voltage value under the same light spot is obtained, and the full width W of the measured scanning light beam at the first measurement distance is obtained according to the first position and the fourth position. o ; Change the transmit power of the laser radar under test, obtain the corresponding relationship curve of voltage and spot half-peak width, and obtain the corresponding relationship curve of voltage and beam full width. In the corresponding relationship curve of voltage and spot half-peak width, the horizontal axis is used to represent the maximum voltage value of the spot, and the vertical axis is used to represent the spot half-peak width W corresponding to a maximum voltage value. f In the curve diagram of the corresponding relationship between voltage and full width of the beam, the horizontal axis is used to represent the maximum voltage value of the light spot, and the vertical axis is used to represent the full width of the beam corresponding to a maximum voltage value W. o The value of The transmission power range of the laser radar under test is determined based on the corresponding relationship curve diagram between the voltage and the half-peak width of the light spot, and the corresponding relationship curve diagram between the voltage and the full width of the light beam.

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