CN116953667A

CN116953667A - Laser radar detection method and laser radar

Info

Publication number: CN116953667A
Application number: CN202210390304.8A
Authority: CN
Inventors: 程为军; 刘豪; 田津铭; 刘旭岗; 陶俊; 朱雪洲; 向少卿
Original assignee: Hesai Technology Co Ltd
Current assignee: Hesai Technology Co Ltd
Priority date: 2022-04-14
Filing date: 2022-04-14
Publication date: 2023-10-27

Abstract

A method of detection of a lidar, the lidar comprising: a plurality of light emitting units; the detection method comprises the following steps: the first acquisition and the second acquisition are carried out sequentially; the detection method further comprises the following steps: the second power configuration employed by the second acquisition is obtained based on the plurality of first signals obtained by the first acquisition. The first acquisition is used as a pre-acquisition for detecting the view field angle of the high-reflectivity barrier or the reflecting position with high reflectivity; the second power configuration in the second acquisition is obtained based on the result of the first acquisition, so when the reflection position with high reflectivity is found, the second power configuration adopted as the second acquisition being acquired is adjusted to reduce the light intensity of the detection light projected to the reflection position with high reflectivity during the second acquisition, thereby effectively avoiding the crosstalk caused by the strong echo light generated by the reflection position with high reflectivity and effectively improving the light crosstalk problem among receiving pixels.

Description

Laser radar detection method and laser radar

Technical Field

The present invention relates to laser detection, and more particularly, to a laser radar and a method for detecting laser radar.

Background

The laser radar is a commonly used ranging sensor, has the characteristics of long detection distance, high resolution, small environmental interference and the like, and is widely applied to the fields of intelligent robots, unmanned aerial vehicles and the like. The laser radar works on the principle that information such as the distance or speed of a target is estimated by using the time taken for laser light to travel between the radar and the target, or the frequency shift generated by frequency modulated continuous light traveling between the radar and the target.

All-solid-state flash laser radar has the advantages of compactness and low cost due to the characteristics of small size and integration, and is concerned by industry. The transmitting end of the Flash laser radar is based on the area array laser, the receiving end is based on the area array detector, the space view field angle of single scanning is increased, the acquisition speed of each frame of image can be improved, the area array device is beneficial to being integrated with a front-end circuit, and the laser radar is beneficial to being miniaturized and developed with low cost.

However, the operation of the existing flash lidar makes the problem of optical crosstalk severe when high reflectivity objects are encountered.

Disclosure of Invention

The problem addressed by the present invention is how to improve the optical crosstalk problem when encountering high reflectivity objects.

In order to solve the above problems, the present invention provides a detection method of a laser radar, the laser radar including: a plurality of light emitting units; the detection method comprises the following steps: the first acquisition and the second acquisition are carried out sequentially; wherein the first acquisition comprises: transmitting a plurality of first detection lights in parallel through the plurality of light emitting units in a first power configuration, wherein the first power configuration comprises power of each light emitting unit when the first detection lights are transmitted, and the plurality of first detection lights are in one-to-one correspondence with the plurality of light emitting units; each first detection light is reflected to form corresponding first echo light; receiving the first echo light to obtain a corresponding first signal; the second acquisition comprises: emitting at least one second probe light in parallel through at least one light emitting unit in a second power configuration, the second power configuration comprising power of each of the light emitting units when emitting the second probe light, the second power configuration comprising: standard power, the said standard power is greater than the power of the correspondent light-emitting unit while transmitting the said first detection light; the second detection light is reflected to form corresponding second echo light; receiving the second echo light to obtain a corresponding second signal; the detection method further comprises the following steps: the second power configuration is obtained based on a plurality of the first signals.

Optionally, the step of obtaining the second power configuration based on the first signal includes: judging whether a light emitting unit emitting first detection light corresponding to the first signal is a first light emitting unit or a second light emitting unit based on the first signal; when the light-emitting unit emitting the first detection light corresponding to the first signal is judged to be the first light-emitting unit, in the second acquisition process, the power of the first light-emitting unit is the standard power.

Optionally, the second power configuration further includes: adjusting power, wherein the adjusting power is smaller than the standard power; when the light emitting unit emitting the first detection light corresponding to the first signal is judged to be a second light emitting unit, in the second acquisition process, the power of the second light emitting unit is the adjustment power.

Optionally, the adjustment power is equal to 0; the detection method further comprises the following steps: and obtaining the distance information of the reflecting position corresponding to the second transmitting unit based on the first signal.

Optionally, the adjustment power is greater than 0; the detection method further comprises the following steps: and obtaining information of the reflection position corresponding to the second transmitting unit based on the first signal and the second signal.

Optionally, based on the first signal, the step of determining whether the light emitting unit emitting the first detection light corresponding to the first signal is the first light emitting unit includes: comparing the intensity of the first signal with a relative magnitude of a preset threshold; when the intensity of the first signal is smaller than or equal to the preset threshold value, judging that a light emitting unit emitting first detection light corresponding to the first signal is the first light emitting unit; and when the intensity of the first signal is larger than the preset threshold value, judging that the light-emitting unit emitting the first detection light corresponding to the first signal is the second light-emitting unit.

Optionally, the first acquisition includes a plurality of measurements, in each of which each light emitting unit transmits a first detection pulse with a corresponding power in the first power configuration, and receives a first echo pulse formed by reflection of the first detection pulse; the second acquisition comprises a plurality of measurements, in each measurement, at least one light emitting unit emits a second detection pulse with corresponding power in the second power, and receives a second echo pulse formed by reflection of the second detection pulse.

Optionally, in each measurement of the first acquisition, the lidar receives an optical signal to obtain corresponding detection data, where the detection data includes time information and intensity information corresponding to the time information, and integrates detection data corresponding to multiple measurements to obtain the first signal; in each measurement of the second acquisition, the laser radar receives an optical signal to obtain corresponding detection data, wherein the detection data comprises time information and intensity information corresponding to the time information, and the detection data respectively corresponding to the multiple measurements are accumulated to obtain the second signal.

Correspondingly, the invention also provides a laser radar, which comprises: a plurality of light emitting units; a detection device adapted to carry out the detection method of the present invention.

Optionally, the light emitting unit includes a vertical facet laser.

Optionally, the lidar comprises an area array detector.

Optionally, the area array detector includes: a plurality of receiving units adapted to receive the reflected wave light.

Optionally, the receiving unit is a geiger mode-based receiving unit.

Optionally, the receiving unit comprises a plurality of single photon avalanche diodes connected in parallel.

Compared with the prior art, the technical scheme of the invention has the following advantages:

according to the technical scheme, the first acquisition performed with lower power is used for pre-acquisition to detect the view field angle of the high-reflectivity obstacle or the reflection position with high reflectivity; the second power configuration in the second acquisition is based on the result of the first acquisition, that is, the plurality of first signals are obtained, so that when the reflection position with high reflectivity is found, the second power configuration adopted as the second acquisition being acquired is adjusted to reduce the light intensity of the detection light projected to the reflection position with high reflectivity during the second acquisition, thereby effectively avoiding the crosstalk caused by the generation of strong echo light at the reflection position with high reflectivity and effectively improving the optical crosstalk problem between receiving pixels.

Drawings

FIG. 1 is a schematic diagram of a laser radar according to an embodiment of the present invention;

FIG. 2 is a schematic top view of the lidar embodiment shown in FIG. 1;

FIG. 3 is a schematic diagram of the correspondence between linear light sources and area array detectors of the lidar of FIG. 1;

FIG. 4 is a schematic view showing a structure of a light emitting unit in the laser radar shown in FIG. 1;

FIG. 5 is a flow chart of a detection method implemented by the detection device in the laser radar embodiment shown in FIG. 1;

FIG. 6 is a schematic diagram of accumulating the obtained multiple corresponding detection data to obtain the first signal in the embodiment of the lidar detection method shown in FIG. 5;

FIG. 7 is a flow chart illustrating the step of obtaining the second power configuration based on a plurality of the first signals in the lidar detection method of FIG. 5;

FIG. 8 is a schematic diagram of obtaining information of a reflection position corresponding to the second light emitting unit according to the first signal in the embodiment of the laser radar detection method shown in FIG. 5;

FIG. 9 is a schematic diagram of a light emitting unit and a light spot formed by the light emitting unit according to another embodiment of the laser radar of the present invention;

fig. 10 is a schematic diagram of a light emitting unit and a receiving unit of another embodiment of the lidar of the present invention.

Detailed Description

As known from the background art, the problem of optical crosstalk is serious when the laser radar in the prior art encounters an object with high reflectivity. The reason for the optical crosstalk problem of the laser radar is analyzed by combining the working mode of the laser radar:

the whole area array laser is fully opened when the early flash laser radar (Basic Flash LiDAR) scans once, and the whole field of view is illuminated. This mode of operation requires that all detectors at the receiving end operate simultaneously to avoid laser energy losses.

Multi-Beam Flash LiDAR (Multi-Beam Flash LiDAR) was developed based on surface-emitting Flash LiDAR. In the multi-beam transmitting flash laser radar, only part of lasers are turned on at a time, a plurality of laser beams are emitted to illuminate a local view field, and part of detectors corresponding to the view field are correspondingly turned on to receive signals, so that the energy efficiency of the flash laser radar is improved.

Further developed is a continuous light-emitting flash laser radar (Sequential Flash LiDAR), which generally operates in such a manner that one or more columns (rows) of lasers emit light simultaneously, echo signals are received at the receiving end correspondingly in accordance with the columns (rows) or the rows (rows) simultaneously, and then a whole frame of image is formed by working column by column. The continuous light flash laser radar can perform one-dimensional addressing and control a certain column (row) or a plurality of columns (row) of lasers.

In any Flash LiDAR, a plurality of receiving pixels at a receiving end are required to work in parallel. When a high reflectivity object such as a sign on a road surface is encountered, the sign has a retro-reflective surface that reflects incident light almost completely back, and the flash lidar operates in such a way that the problem of optical crosstalk between pixels operating simultaneously becomes serious. For example, in a continuous luminescence flash lidar, it is assumed that a high-reflection point exists at a detection position corresponding to a certain pixel, and due to the characteristics that the echo signal energy reflected by the high-reflection point is relatively large and the light is not completely concentrated and distributed in space, a plurality of pixels adjacent to the same column and even the whole column of pixels respond simultaneously, so that crosstalk phenomenon among the pixels in the same column is caused.

In order to solve the technical problem, the invention provides a detection method of a laser radar, the laser radar comprises: a plurality of light emitting units; the detection method comprises the following steps: the first acquisition and the second acquisition are carried out sequentially; wherein the first acquisition comprises: transmitting a plurality of first detection lights in parallel through the plurality of light emitting units in a first power configuration, wherein the first power configuration comprises power of each light emitting unit when the first detection lights are transmitted, and the plurality of first detection lights are in one-to-one correspondence with the plurality of light emitting units; each first detection light is reflected to form corresponding first echo light; receiving the first echo light to obtain a corresponding first signal; the second acquisition comprises: emitting at least one second probe light in parallel through at least one light emitting unit in a second power configuration, the second power configuration comprising power of each of the light emitting units when emitting the second probe light, the second power configuration comprising: standard power, the said standard power is greater than the power of the correspondent light-emitting unit while transmitting the said first detection light; the second detection light is reflected to form corresponding second echo light; receiving the second echo light to obtain a corresponding second signal; the detection method further comprises the following steps: the second power configuration is obtained based on a plurality of the first signals.

In order that the above objects, features and advantages of the invention will be readily understood, a more particular description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings.

Referring to fig. 1 and 2, fig. 1 shows a schematic structural diagram of an embodiment of the lidar of the present invention;

fig. 2 is a schematic top view of the lidar embodiment shown in fig. 1.

The laser radar includes: a plurality of light emitting units 111i. Specifically, the laser radar includes: an emission module 110, the emission module 110 including the plurality of light emitting units 111i.

As shown in fig. 1, in some embodiments of the present invention, the plurality of light emitting units 111i are arranged along the first direction to form a one-dimensional array, that is, the emitting module 110 includes a linear array light source 111, and the linear array light source 111 includes the plurality of light emitting units 111i. Specifically, in some embodiments of the present invention, the first direction of the linear array light source 111 is a direction perpendicular to the horizontal plane. The linear array light source includes M light emitting units 111i.

Each of the light emitting units 111i is adapted to generate probe light. In some embodiments of the present invention, each of the light emitting units 111i is an independently addressed and independently controlled light emitting unit 111i, that is, each of the light emitting units 111i may be individually powered up and individually driven, and only the light emitting unit 111i on a specific address line may be powered up and driven to turn on or off the specific light emitting unit 111i. Specifically, the light Emitting unit 111i includes a vertical cavity surface Emitting Laser (Vertical Cavity Surface-Emitting Laser, VCSEL).

According to the embodiment of the invention, each light emitting unit is independently driven, namely, the driving signals are independently loaded to each light emitting unit, so that the transmission path of the driving signals is effectively shortened, the light emitting power difference of a plurality of light emitting units on a linear array light source is reduced or even eliminated, and the uniformity of the detection capability of the laser radar in the field of view is improved.

In some embodiments of the present invention, the light emitting units 111i are single-grain lasers, i.e., each light emitting unit is a separate laser chip.

In other embodiments of the present invention, the light emitting units 111i may be integrated on the same chip, that is, the linear array light source 111 may be a linear array laser chip, that is, the light emitting units arranged linearly are integrated on the same chip, and separate driving and separate control are implemented by structural isolation of each light emitting unit.

The emission module 110 of the present invention is a one-dimensional array of light emitting units 111i, which is easy to realize independent control. Compared with the area array laser, the one-dimensional array light emitting units 111i can realize denser laser arrangement, so that the power density is higher; the emission module 110 of the present invention can also increase the light emitting area of the light emitting unit 111i with respect to the same field of view, for example, a greater number of lasers, compared to the area array lasers of the related art, thereby further increasing the light emitting power. Therefore, the transmitting module 110 of the present invention, i.e. the transmitting module 110 including the linear array light source 111, can effectively improve the ranging capability of the laser radar.

It should be noted that, in some embodiments of the present invention, the lidar further includes: the scanning device 120 deflects the probe light generated by the emission module 110 to perform scanning.

In some embodiments of the present invention, the scanning device 120 includes a turning mirror (not shown), and a rotation axis 121 of the turning mirror is parallel to the first direction of the line array light source. As shown in fig. 1 and 2, in some embodiments, the scanning device 120 is adapted to scan the probe light in a horizontal field of view, that is, the turning mirror 120 emits the probe light in different horizontal angles of view, the rotation axis 121 of the turning mirror is vertical to a horizontal plane,

the first direction of the line array light source is a direction perpendicular to a horizontal plane. Specifically, the rotating mirror is a polygon rotating mirror. The turning mirror illustrated in fig. 1 is a three-sided turning mirror, i.e. the turning mirror has three reflecting surfaces.

As shown in fig. 1 and 2, in some embodiments of the present invention, the lidar further includes: an emission optical component 112, the emission optical component 112 being located on the optical path of the probe light between the emission module 110 and the scanning device 120. After the beam expansion and collimation operations of the emission optical component 112, the probe light generated by the emission module 110 is reflected by the scanning device 120 to a three-dimensional space.

The reflected probe light is reflected by an obstacle in the three-dimensional space to form a return light.

In some embodiments of the invention, the lidar comprises an area array detector. Specifically, the lidar includes a detection module 130 to receive the echo light, and the detection module 130 includes the area array detector.

It should be noted that, in some embodiments of the present invention, the lidar further includes: a receiving optical component 132, wherein the receiving optical component 132 is positioned on the optical path of the return wave light of the detection module 130 towards the obstacle side. The echo light formed by the reflection of the obstacle is transmitted by the receiving optical component 132 and then projected to the detection module 130.

The lidar further comprises: and a detection module 130, wherein the detection module 130 is suitable for receiving the reflected wave light to realize detection of the target to be detected.

Specifically, the detection module 130 includes: an area array detector 131, the area array detector 131 comprising: a plurality of receiving units 131i arranged in an array along the first direction and the second direction; the scanning device 120 deflects around at least one rotation axis 121, so that the plurality of receiving units 131i arranged along the second direction of the area array detector 131 sequentially receive the reflected light.

In some embodiments of the present invention, the receiving unit 131i is a receiving unit based on a geiger mode, i.e. the receiving unit 131i is a device with a reverse bias voltage exceeding a breakdown voltage. In particular, the receiving unit 131i comprises a plurality of parallel single photon avalanche diodes (Single Photon Avalanche Diode, SPAD).

Referring to fig. 3 in combination, a schematic diagram of the correspondence between linear array light sources and area array detectors in the lidar of fig. 1 is shown.

The plurality of receiving units 131i in the area array detector 131 are arranged in an array manner with the first direction Y and the second direction X intersecting each other as a column direction and a row direction. Specifically, in some embodiments, the first direction Y and the second direction X of the area array detector 131 are perpendicular to each other, the first direction Y of the area array detector 131 is a direction perpendicular to the horizontal plane, and the second direction X of the area array detector 131 is parallel to the horizontal plane.

Referring to fig. 1 to 3 in combination, as the scanning device 120 rotates around the rotation axis 121, the emitting direction of the probe light generated by the linear array light source 111 is changed, and the formed echo light is received by different receiving units 131 i. Specifically, along with the rotation of the turning mirror, the plurality of receiving units 131i arranged along the second direction of the area array detector 131 sequentially receive the reflected light.

As shown in fig. 3, when the scanning device 120 is turned to the jth angle, the plurality of light emitting units 111i in the linear array light source 111 are in one-to-one correspondence with the jth row of receiving units 131i in the area array detector 131 to form a detection channel, that is, when the scanning device 120 is turned to the jth angle, the linear array light source 111 and the corresponding jth row of receiving units 131i correspond to the same field of view in the far field; echo light formed by reflection of the probe light generated by the light emitting unit 111i is received by the corresponding receiving unit 131i in the j-th column.

When the scanning device 120 rotates to the (j+1) th angle, the plurality of light emitting units 111i in the linear array light source 111 and the (j+1) th column receiving units 131i in the area array detector 131 are in one-to-one correspondence to form a detection channel, that is, when the scanning device 120 rotates to the (j+1) th angle, the linear array light source 111 and the corresponding (j+1) th column receiving units 131i correspond to the same field of view in the far field; echo light formed by reflection of the probe light generated by the light emitting unit 111i is received by the corresponding receiving unit 131i in the (j+1) th column.

In some embodiments of the present invention, the receiving unit 131i includes a receiving pixel 131p.

In other embodiments of the present invention, the receiving unit 131i includes: a plurality of receiving pixels 131p. The plurality of receiving pixels 131p are a plurality of receiving pixels arranged in the Y direction, or a plurality of receiving pixels arranged in the X direction, or a plurality of receiving pixels arranged in a two-dimensional array in the X direction and the Y direction. In addition, the composition of the various receiving units may also be used in the same embodiment.

In some embodiments of the present invention, the plurality of receiving pixels 131p are arranged along the first direction Y of the area array detector 131. Specifically, when the scanning device 120 turns to the ith angle, the echo light formed by the reflected probe light generated by the light emitting unit 111i is received by the plurality of receiving pixels 131p in the corresponding receiving unit 131 i.

In some embodiments of the present invention, the cross-sectional area of the beam of the probe light generated by each light emitting unit 111i is larger than the dimension along the first direction of the linear light source than the dimension along the second direction of the linear light source, so that the plurality of receiving pixels 131p in the same receiving unit 131i can be covered by the same echo light at the same time, that is, the plurality of receiving pixels 131p in the same receiving unit 131i can all receive the echo light formed by the same probe light.

As described above, the first direction Y of the linear light source 111 is a direction perpendicular to the horizontal plane, and the first direction Y of the area array detector 131 is also a direction perpendicular to the horizontal plane, that is, the first direction Y of the linear light source 111 is parallel to the first direction Y of the area array detector 131.

Therefore, in some embodiments of the present invention, the receiving unit 131i includes: k receiving pixels 131p, k being an integer greater than 1; the ratio of the size Y along the first direction of the linear array light source 111 to the size along the second direction of the linear array light source is k:1.

Referring to fig. 4 in combination, a schematic structural view of one light emitting unit 111i in the lidar shown in fig. 1 is shown.

In some embodiments of the present invention, the laser is arranged in a stripe shape, that is, the light emitting area of the laser is arranged in a stripe shape, so as to form the probe light meeting the requirement.

As shown in fig. 4, the size of the light emitting area 111l of each light emitting unit 111i in the first direction Y of the linear array light source 111 (shown in fig. 3) is larger than the size in the second direction X of the linear array light source 111, which is perpendicular to the first direction Y of the linear array light source 111.

Specifically, the ratio of the dimension W1 of the light emitting region 111l of each light emitting unit 111i in the first direction Y of the linear array light source 111i (shown in fig. 3) to the dimension H1 in the second direction X of the linear array light source 111 (shown in fig. 3) is k:1. When the shape of the light emitting region 111l of the light emitting unit 111i satisfies the above condition, the ratio of the vertical divergence angle to the horizontal divergence angle of the emitted probe light after shaping the probe light generated by the light emitting unit 111i is k:1.

In some embodiments of the present invention, the light emitting unit 111i includes: vertical cavity surface emitting lasers. The vertical cavity surface emitting laser comprises a plurality of resonant cavities which are electrically connected with each other, the resonant cavities are arranged into a two-dimensional array, and the ratio of the size of the two-dimensional array along the first direction Y of the linear array light source to the size of the two-dimensional array along the second direction X of the linear array light source is k:1. The multiple resonant cavities emit light simultaneously under the drive of the same drive signal, and a beam of detection light is formed to emit after shaping, so that the ratio of the divergence angle of the emitted detection light in the vertical direction to the divergence angle of the detection light in the horizontal direction is k 1.

It should be noted that, in some embodiments of the present invention, the number of receiving pixels 131p in the plurality of receiving units 131i is equal. The number of receiving pixels 131p in the different receiving units 131i is made equal so that the lidar has a uniform ranging capability in the field of view.

It should be noted that the plurality of receiving units 131i are arranged at uniform intervals, and each receiving unit 131i (i.e., the pixels of the area array detector 131) corresponds to a field angle Φ (H) ×Φ (V). The horizontal angle of view Φ (H) and the vertical angle of view Φ (V) of each receiving unit 131i determine the maximum of the horizontal resolution and the vertical resolution of the lidar.

Furthermore, the area array detector 131 has N columns in the row direction and k×m rows along the columns, i.e., the area array detector 131 has N columns in the second direction and k×m rows in the first direction. The detectable field angle of the laser radar is N.phi.H.times.k.M.phi.V. Therefore, the use of the large-area array detector 131 can obtain a large field of view range.

On the other hand, echo light formed by the probe light generated by one light emitting unit 111i is collected by k receiving pixels 131p in one receiving unit 131 i. The linear array light source 111 in the emission module 110 only includes M light emitting units 111i, and the number of the light emitting units 111i in the emission module 111 is far smaller than the number of the receiving pixels 131p in the detection module 131, i.e. the number of the light emitting units 111i in the laser radar can be greatly reduced, the device cost can be effectively reduced, and the related problems of processing yield equipment energy consumption, heat dissipation and the like are improved.

It should be noted that, when the size of the light spot formed by the echo light on the area array detector 131 is larger than the receiving pixel 131p, the minimum resolution of the signal obtained by the lidar is determined by the size of the receiving pixel 131 p; when the size of the spot formed by the echo light on the area array detector 131 is smaller than the receiving pixel 131p, the minimum resolution of the signal obtained by the lidar is determined by the divergence angle of the probe light generated by the linear array light source. It can be seen that, along the second direction X of the area array detector 131, a smaller divergence angle of the outgoing probe light can achieve a higher horizontal angular resolution; in the first direction Y of the area array detector 131, a plurality of receiving pixels 131p are disposed in the receiving units 131i corresponding to the light emitting units 111i, and the receiving pixels 131p of a smaller size effectively ensure a higher vertical angular resolution. Therefore, the arrangement method in which the echo light formed by the detection light generated by one light emitting unit 111i is detected by the receiving unit having a plurality of receiving pixels can keep the resolution of the laser radar unchanged while reducing the number of light emitting units 111i in the laser radar.

With continued reference to fig. 1, the lidar further includes: and a detecting device (not shown) connected to the plurality of light emitting units, the detecting device being adapted to control the plurality of light emitting units to suppress optical crosstalk caused by the high-reflectivity reflection position.

Referring to fig. 5 in combination, a flow chart of a detection method implemented by the detection device in the laser radar embodiment shown in fig. 1 is shown.

As shown in fig. 5, the detection method includes: step S110, the first acquisition and step S120, the second acquisition are performed sequentially.

Wherein, in step S110, the first acquisition includes: step S111 is first executed, where a plurality of first detection lights are emitted in parallel through the plurality of light emitting units in a first power configuration, where the first power configuration includes power of each light emitting unit when the first detection lights are emitted, and the plurality of first detection lights are in one-to-one correspondence with the plurality of light emitting units; each first detection light is reflected to form corresponding first echo light; step S112 is executed to receive the first echo light to obtain a corresponding first signal; step S120, the second acquiring includes: first, step S121 is performed, wherein at least one second probe light is emitted in parallel by the at least one light emitting unit in a second power configuration, the second power configuration including power of each light emitting unit when the second probe light is emitted, the second power configuration including: standard power, the said standard power is greater than the power of the correspondent light-emitting unit while transmitting the said first detection light; the second detection light is reflected to form corresponding second echo light; step S122 is then performed to receive the second echo light to obtain a corresponding second signal.

The detection method further comprises the following steps: step S130 is performed to obtain the second power configuration based on the plurality of first signals, so as to suppress optical crosstalk caused by reflection echo of the high-reflectivity obstacle, that is, step S130 is performed between performing step S110 to perform the first acquisition and performing step S120 to perform the second acquisition, and the second power configuration is obtained based on the plurality of first signals.

The first acquisition, performed at lower power, is pre-acquired to detect the field angle of the high reflectivity obstacle, otherwise known as the high reflectivity reflection position; the second power configuration in the second acquisition is based on the result of the first acquisition, that is, the plurality of first signals are obtained, so that when the reflection position with high reflectivity is found, the second power configuration adopted as the second acquisition being acquired is adjusted to reduce the light intensity of the detection light projected to the reflection position with high reflectivity during the second acquisition, thereby effectively avoiding the crosstalk caused by the generation of strong echo light at the reflection position with high reflectivity and effectively improving the optical crosstalk problem between receiving pixels.

The transceiver of the lidar used in the detection method is the transceiver of the present invention. However, the transceiver of the lidar used in the detection method may not be the transceiver of the present invention. The technical scheme of the detection method is not particularly limited to the laser radar transceiver.

In some embodiments of the present invention, the transmitting module 110 of the lidar includes a linear array light source 111, and the detecting module 130 of the lidar includes the area array detector; the laser radar has a scanning device 120 to deflect the probe light generated by the emitting module 110 to realize scanning. Thus, as shown in fig. 5, before performing step S110 to perform the step of first acquisition, the detection method further includes: step S101 is performed to determine the detection angle.

Specifically, the scanning device 120 includes a rotating mirror, so that step S101 is performed, and in the step of determining the detection angle, t _n At the moment, the rotating mirror rotates to a detection angle theta _n 。

With continued reference to FIG. 5, a detection angle θ is determined _n After that, step S110, the first acquisition, step S120, and the second acquisition are sequentially performed.

In step S110, the first acquisition is used as a pre-acquisition to detect the reflection position with high reflectivity.

In some embodiments of the invention, the first acquisition comprises a plurality of measurements. In each measurement, each light emitting unit 111i transmits a first detection pulse in parallel with the corresponding power in the first power configuration, and receives a first echo pulse formed by reflecting the first detection pulse in a time window of one measurement; the laser radar receives the first echo pulse, and obtains detection data corresponding to the measurement, wherein the detection data comprises time information and intensity information corresponding to the time information.

Specifically, in one measurement, each light emitting unit 111i transmits a first detection pulse in parallel with the corresponding power in the first power configuration, and receives a first echo pulse formed by reflecting the first detection pulse in a time window of one measurement; and the laser radar receives the first echo pulse and obtains detection data corresponding to the measurement. In the next measurement, the light emitting unit 111i emits the first detection pulse again, and the receiving unit receives the first echo pulse formed by reflecting the first detection pulse in the time window of the one measurement to obtain the detection data corresponding to the one measurement. And finishing a plurality of measurement steps of the first acquisition, accumulating detection data corresponding to a plurality of first echo pulses respectively, and obtaining the first signal.

Specifically, in the laser radar embodiment shown in fig. 1, the plurality of light emitting units 111i of the linear array light source 111 in the emitting module 110 of the laser radar emit a plurality of first detection lights in parallel in a first power configuration. Wherein, the M light emitting units 111i in the linear array light source 111 all emit the first detection light in parallel with the power in the first power configuration.

The first detection light is reflected to form corresponding first echo light, and the area array detector 131 receives all the first echo light in parallel. Specifically, the area array detector 131 is at an angle θ to the detection angle θ _n A corresponding column of kxm receiving units 131i receives all of the first echo lights in parallel.

As mentioned above, in some embodiments of the present invention, the receiving unit 131i is a geiger-mode-based receiving unit, and the receiving unit 131i includes a plurality of parallel single photon avalanche diodes (Single Photon Avalanche Diode, SPAD).

In some embodiments of the present invention, the receiving unit 131i comprises one or more receiving pixels comprising a plurality of single photon avalanche diodes connected in parallel. The output ends of the single photon avalanche diodes connected in parallel in the receiving pixels are connected to the same receiving circuit, and obstacle distance information is obtained according to the time difference between the receiving time of the echo light and the transmitting time of the detection light, so that one data point on the point cloud is obtained.

Thus, in step S110, the first acquisition comprises a plurality of measurements, each of which is performed by each light emitting unit transmitting a first detection pulse with a corresponding power in the first power configuration, and receiving a first echo pulse formed by reflection of the first detection pulse. In each measurement of the first acquisition, the laser radar receives an optical signal to obtain corresponding detection data, wherein the detection data comprises time information and intensity information corresponding to the time information, and the detection data respectively corresponding to the multiple measurements are accumulated to obtain the first signal.

Specifically, each of the light emitting units 111i emits a first detection pulse at the corresponding power in the first power configuration, and the corresponding receiving unit 131i receives the optical signal within a preset time window, thereby completing one measurement. As shown in fig. 6, each measurement, the receiving unit 131i receives an optical signal, and obtains corresponding probe data including time information and intensity information corresponding to the time information in response to the optical signal. Specifically, the time information in the corresponding probe data refers to a time interval between the time of the response of the receiving unit 131i and the transmission time of the first probe pulse, and the intensity information corresponding to the time information refers to the intensity of the light received by the receiving unit 131. In some embodiments, in the first acquisition, the time intervals of the time windows of each measurement are the same.

It should be noted that, the receiving pixel 131p includes a plurality of parallel single photon avalanche diodes, and each time a measurement is performed, the single photon avalanche diode receives an optical signal within a time window, and after responding to the optical signal, obtains detection data corresponding to a response, where the corresponding detection data includes time information and intensity information of the response.

In particular, the time information may be a time stamp quantized by a time-to-digital converter (TDC) and the time interval obtained by subtracting the emission time of the first probe pulse, and the intensity information may be represented by the number of single photon avalanche diodes triggered in the receiving pixel 131 p. The single photon avalanche diode is quenched after being triggered by photons, can recover to a Geiger mode after the recovery time, can be triggered by photons again, and the recovery time is far smaller than a time window of one measurement, so that the single photon avalanche diode can be triggered by responding to an optical signal for a plurality of times in the time window. The detection data of one measurement includes time information and intensity information corresponding to each response of the single photon avalanche diode in the receiving pixel 131p in the time window of one measurement.

Referring to fig. 6, the light emitting unit 111i sequentially emits i times of first detection pulses with the power corresponding to the first power configuration, and the corresponding receiving units 131i sequentially receive i times of first echo pulses formed by reflecting the i times of first detection pulses, so as to obtain i times of corresponding detection data; and accumulating the obtained i times of corresponding detection data by the laser radar to obtain the first signal so as to finish the first acquisition. Since the corresponding probe data includes time information and intensity information corresponding to the time information, the accumulating is to accumulate a plurality of intensity information corresponding to the same time information, and the accumulating the first signal obtained by the corresponding probe data includes: the distribution of the time information detected i times and the intensity distribution corresponding to the time information, that is, the first signal is a relationship in which the signal intensity varies with time.

Specifically, the receiving unit 131i includes a plurality of parallel single photon avalanche diodes, and intensity information in the corresponding detection data is represented by the number of single photon avalanche diodes triggered simultaneously; the first signal obtained by accumulating the i times of corresponding detection data is a time-photon number histogram, wherein the horizontal axis of the histogram represents time, and the vertical axis represents the sum of the trigger numbers at the same time information in the i times of measurement, and the sum can reflect the light intensity.

In the first collection, the plurality of light emitting units 111i emit a plurality of first detection lights in parallel, so the plurality of receiving units 131i receive a plurality of first echo lights in parallel to obtain a plurality of corresponding first signals. The plurality of first signals are in one-to-one correspondence with the plurality of light emitting units 111 i.

Step S120, the second acquisition is used as a positive acquisition to obtain distance information of the reflection position.

In some embodiments of the present invention, the second acquisition includes a plurality of measurements, and in each measurement, at least one light emitting unit emits a second detection pulse with a corresponding power of the second powers, and receives a second echo pulse formed by reflection of the second detection pulse. In each measurement of the second acquisition, the laser radar receives an optical signal to obtain corresponding detection data, wherein the detection data comprises time information and intensity information corresponding to the time information, and the detection data respectively corresponding to multiple measurements are accumulated to obtain the second signal

Specifically, in each measurement, at least one light emitting unit 111i emits multiple second detection pulses in parallel with corresponding power in the second power, and receives a second echo pulse formed by reflecting the second detection pulse in a time window of one measurement; the laser radar receives the second echo pulse, and obtains detection data corresponding to the measurement, wherein the detection data comprises time information and intensity information corresponding to the time information.

Specifically, in one measurement, the at least one light emitting unit 111i emits a plurality of second detection pulses at a corresponding power in the second power, and receives a second echo pulse formed by reflecting the second detection pulse in a time window of one measurement; and the laser radar receives the second echo pulse and obtains detection data corresponding to the measurement. In the next measurement, the light emitting unit 111i emits the second detection pulse again, and the receiving unit receives the second echo pulse formed by reflecting the second detection pulse within the time window of the one measurement to obtain the detection data corresponding to the one measurement. And finishing a plurality of measurement steps of the second acquisition, and accumulating detection data corresponding to a plurality of second echo pulses respectively to obtain the second signal.

Specifically, in the laser radar embodiment shown in fig. 1, at least one light emitting unit 111i of the linear array light source 111 in the emitting module 110 of the laser radar emits a plurality of second probe lights in parallel in a second power configuration. Wherein at least one light emitting unit 111i in the linear array light source 111 emits a second probe light in parallel with the power in the second power configuration.

The second detection light is reflected to form a corresponding second echo light, and the area array detector 131 receives all the second echo light in parallel. Specifically, the area array detector 131 is at the detection angle θ _n In a corresponding column of k×m receiving units 131i, at least k receiving units 131i corresponding to the at least one light emitting unit 111i receive all of the second echo light.

As previously described, the receiving unit 131i includes a receiving pixel including a plurality of single photon avalanche diodes connected in parallel.

Thus, similar to step S110, the first acquisition, step S120, the second acquisition comprises a plurality of measurements. Specifically, in each measurement, at least one of the light emitting units 111i emits a second detection pulse with the corresponding power in the second power configuration, and the corresponding receiving unit 131i receives the optical signal within a preset time window, thereby completing one measurement. For each measurement, the receiving unit 131i receives an optical signal, and obtains corresponding probe data in response to the optical signal, where the corresponding probe data includes time information and intensity information corresponding to the time information. Specifically, the time information in the corresponding probe data refers to a time interval between the time of the response of the receiving unit 131i and the transmission time of the second probe pulse, and the intensity information corresponding to the time information refers to the intensity of the light received by the receiving unit 131. In some embodiments, in the second acquisition, the time intervals of the time windows of each measurement are the same.

It should be noted that, when the receiving unit 131i includes a plurality of parallel single photon avalanche diodes, each time a measurement is performed, the single photon avalanche diode receives an optical signal within a time window, and after responding to the optical signal, obtains detection data corresponding to a response, where the corresponding detection data includes time information and intensity information of the response.

In particular, the time information may be a time stamp quantized by the time-to-digital converter, and the time interval obtained by subtracting the emission time of the second detection pulse, and the intensity information may be represented by the number of single photon avalanche diodes triggered in the receiving pixel 131 p. The single photon avalanche diode is quenched after being triggered by photons, can recover to a Geiger mode after the recovery time, can be triggered by photons again, and the recovery time is far smaller than a time window of one measurement, so that the single photon avalanche diode can be triggered by responding to an optical signal for a plurality of times in the time window. The detection data of one measurement includes time information and intensity information corresponding to each response of the single photon avalanche diode in the receiving pixel 131p in the time window of one measurement.

At least one light emitting unit 111i emits j second detection pulses with corresponding power in the second power configuration, and the corresponding receiving units 131i respectively receive the j second echo pulses formed by reflecting the j second detection pulses in sequence, so as to obtain j corresponding detection data; the laser radar accumulates the obtained j detection data to obtain the second signal so as to complete the second acquisition. Since the corresponding probe data includes time information and intensity information corresponding to the time information, the accumulating is to accumulate a plurality of intensity information corresponding to the same time information, and the second signal obtained by accumulating the corresponding probe data includes: the distribution of the j detected time information and the intensity distribution corresponding to the time information, that is, the second signal is a relationship in which the signal intensity changes with time.

Specifically, when the receiving unit 131i includes a plurality of parallel single photon avalanche diodes, intensity information of the corresponding detection data is represented by the number of single photon avalanche diodes triggered simultaneously; the second signal obtained by accumulating the i times of corresponding detection data is a time-photon number histogram, wherein the horizontal axis of the histogram represents time, and the vertical axis represents the sum of the trigger numbers at the same time information in the i times of measurement, and the sum can reflect the light intensity.

In the second collection, the at least one light emitting unit 111i emits a second detection light, so that the corresponding receiving unit 131i receives the corresponding second echo light to obtain a corresponding second signal. When the number of the light emitting units 111i emitting the second probe light is plural, the plural light emitting units 111i emit the second probe light in parallel, and the corresponding receiving units 131i receive the plural second echo lights in parallel.

With continued reference to fig. 5, after performing step S110 and after performing the first acquisition, performing step S120, the detection method further includes: step S130 is performed to obtain the second power configuration based on a plurality of the first signals.

Referring to fig. 7 in combination, a flow chart of the step of obtaining the second power configuration based on a plurality of the first signals in the probing method shown in fig. 5 is shown.

As shown in fig. 7, executing step S130, the step of obtaining the second power configuration based on a plurality of the first signals includes: first, step S131 is performed to determine, based on the first signal, whether a light emitting unit that emits first probe light corresponding to the first signal is a first light emitting unit or a second light emitting unit.

Wherein the first light emitting unit refers to a light emitting unit that emits the first detection light reflected by a non-high reflectance obstacle, that is, a reflectance of a reflection position that reflects the first detection light emitted by the first light emitting unit is relatively low. The second light emitting unit refers to a light emitting unit that emits the first detection light reflected by the high-reflectance obstacle, that is, a reflectance of a reflection position that reflects the first detection light emitted by the second light emitting unit is high. Specifically, the high reflectivity obstacle is an angular reflecting object, and the reflectivity is close to 100%, such as a sign on a road surface.

Specifically, executing step S131, based on the first signal, the step of determining whether the light emitting unit that emits the first probe light corresponding to the first signal is the first light emitting unit includes: comparing the intensity of the first signal with a relative magnitude of a preset threshold; when the intensity of the first signal is smaller than or equal to the preset threshold value, judging that a light emitting unit emitting first detection light corresponding to the first signal is the first light emitting unit; and when the intensity of the first signal is larger than the preset threshold value, judging that the light-emitting unit emitting the first detection light corresponding to the first signal is the second light-emitting unit.

When the detection light irradiates to the reflection position with high reflectivity, the reflectivity of the reflection position is high, so that the intensity of the formed echo light is high correspondingly, and the intensity of the first signal can be judged to be obtained by comparing the intensity of the first signal with the relative intensity of a preset threshold value, so that whether the reflection position for reflecting the first echo light is the reflection position with high reflectivity or not can be judged, and then the light-emitting unit for emitting the corresponding first detection light is the first light-emitting unit or the second light-emitting unit.

In some embodiments of the present invention, since the first signal light includes: the distribution of the time information detected i times and the intensity distribution corresponding to the time information, that is, the first signal is a relationship in which the signal intensity varies with time. Thus, the intensity of the first signal refers to the peak of the signal intensity.

As shown in fig. 7, when it is determined that the light emitting unit emitting the first detection light corresponding to the first signal is the first light emitting unit, step S132 is executed, where in the second collecting process, the power of the first light emitting unit is the standard power, that is, in the second power configuration, the power of the light emitting unit emitting the first detection light corresponding to the first signal is set as the standard power.

And judging that the light-emitting unit emitting the first detection light corresponding to the first signal is the first light-emitting unit, namely, the reflectivity of the reflection position for reflecting the first signal light is lower. The power of the corresponding light emitting unit in the second power configuration is set to the standard power.

It should be noted that, the standard power refers to the light emitting power determined based on the ranging capability of the lidar, and thus the magnitude of the standard power is related to the technical requirement of the ranging capability of the lidar.

As shown in fig. 7, in some embodiments of the present invention, the second power configuration further includes: adjusting power, wherein the adjusting power is smaller than the power of each light emitting unit when the first detection light is emitted; and when the light emitting unit emitting the first detection light corresponding to the first signal is judged to be a second light emitting unit, executing step S133, wherein in the second acquisition process, the power of the second emitting unit is the adjustment power, namely, in the second power configuration, the power of the light emitting unit emitting the first detection light corresponding to the first signal is set as the adjustment power.

And judging that the light-emitting unit emitting the first detection light corresponding to the first signal is a second light-emitting unit, namely, the reflectivity of the reflection position for reflecting the first signal light is higher. The power of the corresponding light emitting unit in the second power configuration is set to the adjusted power.

The standard power is greater than the power of the light emitting unit corresponding to the first probe light being emitted, and the adjustment power is smaller than the power of each light emitting unit when the first probe light being emitted, that is, the adjustment power is smaller than the standard power. In the second collection, the power of the light emitting unit corresponding to the reflection position with high reflectivity for emitting the detection light is lower, and the light intensity of the echo light formed by the reflection position with high reflectivity in the second collection can be effectively reduced, so that the problem of light crosstalk between receiving pixels can be effectively improved.

In some embodiments of the present invention, the adjustment power is equal to 0, i.e. in step S120, the second light emitting unit does not emit light during the second collecting process, i.e. in step S120, the second light emitting unit is turned off during the second collecting process. In other embodiments of the present invention, the adjustment power is greater than 0, that is, in step S120, the power of the second light emitting unit emitting the second probe light is reduced in the second collecting process, that is, in step S120, the second light emitting unit emits light in the second collecting process, but the light emitting power is smaller than that in step S110, and the light emitting power in the first collecting process.

With continued reference to fig. 5, the probing method further includes: step S120, after the second acquisition, step S140 is performed, and distance information of the reflection position corresponding to each light emitting unit is obtained based on at least one of the first signal and the second signal.

It should be noted that in some embodiments of the present invention, the time of flight is obtained according to the principle of time of flight. And obtaining the flight time corresponding to each receiving unit based on at least one of the first signal and the second signal, and further obtaining the distance information of the reflection position corresponding to each light emitting unit.

It should be further noted that, in some embodiments of the present invention, the detection method further includes: and obtaining the reflectivity of the reflection position corresponding to each light emitting unit based on at least one of the first signal and the second signal.

In some embodiments of the present invention, when it is determined that the light emitting unit emitting the first probe light corresponding to the first signal is a first light emitting unit, step S140 is executed, and the step of obtaining the distance information of the reflection position corresponding to each light emitting unit based on at least one of the first signal and the second signal includes: and obtaining the distance information of the reflecting position corresponding to the first transmitting unit based on the first signal and the second signal.

Specifically, the step of obtaining the distance information of the reflection position corresponding to the first transmitting unit based on the first signal and the second signal includes accumulating the first signal and the second signal to obtain the distance information of the reflection position corresponding to the first transmitting unit. The first signals are obtained by accumulating the detection data corresponding to the first echo light for multiple times, and the second signals are obtained by accumulating the detection data corresponding to the second echo light for multiple times, so that the more the number of times of accumulated measurement is, the measurement probability and the measurement precision are effectively improved; accumulating the first signal and the second signal can effectively improve the accuracy of the obtained distance information.

When the receiving unit 131i includes a plurality of parallel single photon avalanche diodes, the first signal is a histogram of superposition of i times of measured detection data, and the second signal is a histogram of superposition of j times of measured detection data; the step of accumulating said first signal and said second signal comprises: based on the first signal and the second signal, a histogram of cumulative superposition of the detection data measured for (i+j) times is obtained, and further distance information of the reflection position corresponding to the first transmitting unit is obtained.

It should be noted that, the method of obtaining the distance information of the reflection position corresponding to the first transmitting unit based on the first signal and the second signal is merely an example, and in other embodiments of the present invention, the distance information of the reflection position corresponding to the first transmitting unit may also be obtained based on one of the first signal and the second signal.

In some embodiments of the present invention, when the light emitting unit emitting the first probe light corresponding to the first signal is determined to be a second light emitting unit, and the adjustment power is equal to 0, step S140 is executed, and based on at least one of the first signal and the second signal, the step of obtaining the distance information of the reflection position corresponding to each light emitting unit further includes: and obtaining the distance information of the reflecting position corresponding to the second transmitting unit based on the first signal.

Since the step S120 is executed, the adjustment power is equal to 0 during the second acquisition, i.e. step S120, and the second light emitting unit does not emit light during the second acquisition. Therefore, only the step S110 is executed, in the first acquisition process, the reflection position corresponding to the second light emitting unit is detected, and the step S120 is executed, in the second acquisition process, the reflection position corresponding to the second light emitting unit is not detected, so that the second signal does not include information of the reflection position corresponding to the second light emitting unit, and only the first signal includes information of the reflection position corresponding to the second light emitting unit.

As shown in fig. 8, after the first acquisition, the light emitting unit 118 is judged as a second light emitting unit, that is, the power of the light emitting unit 118 is set to 0 during the second acquisition; thus from the detection angle theta _n In a corresponding row of kxm receiving units 131i, k receiving units corresponding to the light emitting units 118 do not receive the second echo light (as shown by a circle 118a in fig. 8), and in the second collecting process, the reflection positions corresponding to the light emitting units 118 are not detected; accordingly, information of the reflection position corresponding to the light emitting unit 118 is obtained only according to the first signal (as indicated by a circle 118b in fig. 8).

It can be seen that, although the reflection position corresponding to the second light emitting unit is not detected in the second acquisition process, the information of the reflection position corresponding to the second light emitting unit may be obtained based on the first signal obtained in the first acquisition process. On the one hand, in the second scanning process with larger power, the reflection position corresponding to the second light-emitting unit is not detected, so that the problem of optical crosstalk caused by the excessively strong echo light can be effectively avoided; on the other hand, the first signal obtained based on the first acquisition still can obtain the information of the reflection position corresponding to the second light-emitting unit, so that the resolution is not affected.

In other embodiments of the present invention, when the light emitting unit emitting the first probe light corresponding to the first signal is determined to be the second light emitting unit and the adjustment power is greater than 0, step S140 is executed, and the step of obtaining the distance information of the reflection position corresponding to each light emitting unit based on at least one of the first signal and the second signal further includes: and obtaining the distance information of the reflecting position corresponding to the second transmitting unit based on the first signal and the second signal.

Since the step S120 is executed, the adjustment power is greater than 0 in the second collecting process, that is, in the step S120, the second light emitting unit emits light in the second collecting process, but the light emitting power is smaller than that in the step S110 in the first collecting process. Step S110 is executed, and step S120 is executed, where the first collecting process and the second collecting process both detect the reflection position corresponding to the second light emitting unit, so that the first signal and the second signal both include information of the reflection position corresponding to the second light emitting unit; and the distance information of the reflecting position corresponding to the second transmitting unit is obtained by combining the first signal and the second signal, so that the accumulated measuring times can be increased, and the detection probability and the detection precision are improved.

It should be noted that, in some embodiments of the present invention, the transmitting module 110 of the laser radar includes a linear array light source 111, and the detecting module 130 of the laser radar includes the area array detector; the laser radar sequentially receives echo light formed by the probe light generated by the linear array light source 111 by the scanning device 120 through a plurality of receiving units arranged in the second direction of the area array detector. Thus, after performing step S120, the detection method further comprises: step S101 is performed again to determine the detection angle. Specifically, at t _n+1 At the moment, the rotating mirror rotates to a detection angle theta _n+1 To enter the first acquisition and the second acquisition of the next given detection angle until the scanning of the whole field of view is completed. After the whole view field is scanned, generating point clouds according to the distance information of different detection angles and different reflection positions.

The light emitting units of the linear array light source are light emitting area units which are independently addressed and independently controlled, so that the light emitting power of each light emitting unit can be respectively controlled in the second acquisition, and when the reflectivity of the reflection position for reflecting the first signal light is higher, the light emitting power of the corresponding light emitting unit in the second acquisition is reduced, thereby effectively inhibiting the crosstalk between receiving pixels caused by a high-reflection object.

However, this arrangement is merely an example, and in other embodiments of the present invention, the arrangement may be implemented by a dodging design.

Referring to fig. 9, a schematic diagram of a light emitting unit and a spot formed by the light emitting unit in another embodiment of the laser radar according to the present invention is shown.

In order to form a probe light with a proper cross-sectional area to realize a one-to-many relationship of transceiving, in some embodiments of the present invention, the transceiving apparatus further comprises: an emission optical component 221, the emission optical component 221 being located on the optical path of the probe light 201, the emission optical component 221 comprising: at least one beam expanding element 222; the divergence angle of the probe light 201 transmitted through the emission optical assembly 221 in the first direction Y of the line source is greater than the divergence angle in the second direction X of the line source.

In some embodiments of the present invention, the receiving unit (not shown in the drawings) includes: k receiving pixels 131p, k being an integer greater than 1; therefore, the ratio of the divergence angle of the probe light 201 transmitted through the emission optical assembly 222 in the first direction Y of the linear array light source to the divergence angle in the second direction X of the linear array light source is k:1.

The beam expanding element 222 is adapted to expand the probe light along the first direction Y of the area array detector, so that the probe light exiting toward the obstacle meets the requirements of a vertical divergence angle and a horizontal divergence angle. Specifically, in some embodiments, the beam expanding element 222 may be configured as a cylindrical lens.

Further, in some embodiments of the present invention, the size of the light emitting region 211l of each light emitting unit 211i along the first direction Y of the linear array light source is equal to the size along the second direction X of the linear array light source. The beam expanding element is used for adjusting divergence angles of emergent detection light in different directions, the structure of the light emitting unit 211i is not required to be changed, the light emitting unit can be integrated with the existing light emitting unit, a special device supply chain and a production line are not required, and cost can be effectively controlled.

Referring to fig. 10, a schematic diagram of a light emitting unit and a receiving unit of a lidar according to another embodiment of the present invention is shown.

In this embodiment, the lidar includes an area light source 311 and an area detector 331. The area array light source 311 includes a plurality of light emitting units 311i, and the plurality of light emitting units 311i are arranged in a two-dimensional array in the X-direction and the Y-direction. The plurality of light emitting units 311i of the area array light source 311 are in one-to-one correspondence with the fields of view of the plurality of receiving units of the area array detector 331. The lidar of this embodiment may operate in a mode of Sequential Flash LiDAR, that is, the light emitting units 311i of one column (row) or multiple columns (row) emit light simultaneously, and the receiving units of the corresponding columns (row) or multiple columns (row) of the area array detector 331 receive echo signals simultaneously, so that an entire frame of image is formed by operating column by column.

In some embodiments of the present invention, the plurality of light emitting units 311i of the area array light source 311 can be addressed and controlled independently, so that the detection method provided by the present invention can be used for performing the first acquisition and the second acquisition, and the problem of optical crosstalk caused by strong echo generated by the reflection position with high reflectivity when the plurality of receiving units work simultaneously is improved.

It should be noted that, since the plurality of light emitting units 311i of the area array light source 311 are in one-to-one correspondence with the fields of view of the plurality of receiving units of the area array detector 331 to form detection channels, each detection channel corresponds to a fixed detection angle, and no mechanical rotating component is required as a scanning device, so that the laser radar does not need to combine with the scanning device to determine the detection angle when detecting.

Specifically, the first acquisition is used as a pre-acquisition to detect the reflection position with high reflectivity.

The first acquisition includes a plurality of measurements. In each measurement, each light emitting unit 311i of the area array light source 311 emits a first detection pulse in parallel with the corresponding power in the first power configuration, and receives a first echo pulse formed by reflecting the first detection pulse in a time window of one measurement; each receiving unit in the area array detector 331 receives the corresponding first echo pulse, and obtains the detection data corresponding to the measurement, where the detection data includes time information and intensity information corresponding to the time information.

In one measurement, each light emitting unit 311i of the area array light source 311 emits first detection pulses in parallel with the corresponding power in the first power configuration, and each receiving unit of the area array detector 331 receives first echo pulses formed by reflecting the corresponding first detection pulses in a time window of one measurement; and receiving the first echo pulse to obtain detection data corresponding to the measurement. In the next measurement, each light emitting unit 311i of the area array light source 311 emits the first detection pulse again, and each receiving unit in the area array detector 331 receives the first echo pulse formed by reflecting the corresponding first detection pulse again within the time window of the one measurement to obtain the detection data corresponding to the one measurement. And finishing a plurality of measurement steps of the first acquisition, accumulating detection data corresponding to a plurality of first echo pulses respectively, and obtaining the first signal.

The first acquisition includes a plurality of measurements, each time the measurement is performed, each light emitting unit 311i of the area array light source 311 emits a first detection pulse with a corresponding power in the first power configuration, and each receiving unit of the area array detector 331 receives a first echo pulse formed by reflecting the corresponding first detection pulse. In each measurement of the first acquisition, the laser radar receives an optical signal to obtain corresponding detection data, wherein the detection data comprises time information and intensity information corresponding to the time information, and the detection data respectively corresponding to the multiple measurements are accumulated to obtain the first signal.

Each light emitting unit 311i of the area array light source 311 emits i times of first detection pulses with corresponding power in the first power configuration, and each receiving unit in the area array detector 331 sequentially receives i times of first echo pulses formed by reflecting the corresponding i times of first detection pulses respectively to obtain i times of corresponding detection data; and accumulating the obtained i times of corresponding detection data by the laser radar to obtain the first signal so as to finish the first acquisition. Since the corresponding probe data includes time information and intensity information corresponding to the time information, the accumulating is to accumulate a plurality of intensity information corresponding to the same time information, and the accumulating the first signal obtained by the corresponding probe data includes: the distribution of the time information detected i times and the intensity distribution corresponding to the time information, that is, the first signal is a relationship in which the signal intensity varies with time.

Specifically, the second acquisition is taken as the positive acquisition to detect the reflection position of high reflectivity.

The second acquisition includes a plurality of measurements. In each measurement, at least one light emitting unit 311i in the area array light source 311 emits a second detection pulse in parallel with the corresponding power in the second power configuration, and receives a second echo pulse formed by reflecting the second detection pulse in a time window of one measurement; the receiving unit in the area array detector 331 receives the corresponding second echo pulse, and obtains the detection data corresponding to the measurement, where the detection data includes time information and intensity information corresponding to the time information.

In one measurement, at least one light emitting unit 311i in the area array light source 311 emits a second detection pulse in parallel with the corresponding power in the second power configuration, and in a time window of one measurement, a receiving unit in the area array detector 331 receives a second echo pulse formed by reflecting the corresponding second detection pulse; and receiving the second echo pulse to obtain detection data corresponding to the measurement. In the next measurement, at least one light emitting unit 311i in the area array light source 311 emits a second detection pulse again, and the receiving unit in the area array detector 331 receives a second echo pulse formed by reflecting the corresponding second detection pulse again within a time window of the one measurement to obtain detection data corresponding to the one measurement. And finishing a plurality of measurement steps of the second acquisition, accumulating detection data corresponding to a plurality of second echo pulses respectively, and obtaining the second signal.

The second acquisition includes a plurality of measurements, in each of the measurements, at least one light emitting unit 311i in the area array light source 311 emits a second detection pulse with a corresponding power in the second power configuration, and a receiving unit in the area array detector 331 receives a second echo pulse formed by reflecting the corresponding second detection pulse. In each measurement of the second acquisition, the laser radar receives an optical signal to obtain corresponding detection data, wherein the detection data comprises time information and intensity information corresponding to the time information, and the detection data respectively corresponding to the multiple measurements are accumulated to obtain the second signal.

At least one light emitting unit 311i in the area array light source 311 emits j times of second detection pulses with corresponding power in the second power configuration, and the receiving units in the area array detector 331 respectively receive the j times of second echo pulses formed by reflecting the j times of corresponding second detection pulses in sequence to obtain j times of corresponding detection data; and accumulating the obtained j times of corresponding detection data by the laser radar to obtain the second signal so as to finish the second acquisition. Since the corresponding probe data includes time information and intensity information corresponding to the time information, the accumulating is to accumulate a plurality of intensity information corresponding to the same time information, and the second signal obtained by accumulating the corresponding probe data includes: the distribution of the j detected time information and the intensity distribution corresponding to the time information, that is, the second signal is a relationship in which the signal intensity changes with time.

Wherein the second power configuration is obtained based on a plurality of the first signals. When the detection light irradiates to the reflection position with high reflectivity, the intensity of the echo light correspondingly formed is larger because the reflectivity of the reflection position is higher, the intensity of the first echo light received by the first signal can be judged and obtained by comparing the intensity of the first signal with the relative intensity of a preset threshold value, and whether the reflection position for reflecting the first echo light is the reflection position with high reflectivity or not is judged, so that the light-emitting unit for emitting the corresponding first detection light is a first light-emitting unit or a second light-emitting unit.

And the first signal light includes: the distribution of the time information detected i times and the intensity distribution corresponding to the time information, that is, the first signal is a relationship in which the signal intensity varies with time. Thus, the intensity of the first signal refers to the peak of the signal intensity.

It should be noted that, each receiving unit illustrated in fig. 10 includes one receiving pixel 331p, and in other embodiments of the present invention, the receiving unit may include a plurality of receiving pixels 331p. The plurality of receiving pixels 331p are a plurality of receiving pixels 331p arranged in the Y direction, or a plurality of receiving pixels 331p arranged in the X direction, or a plurality of receiving pixels 331p arranged in a two-dimensional array in the X direction and the Y direction. In addition, the composition of the various receiving units may also be used in the same embodiment.

In summary, the second power configuration is set by sequentially performing a first acquisition and a second acquisition, and based on a first signal obtained by the first acquisition. The first acquisition performed at lower power is pre-acquired to detect the reflective position of high reflectivity; the second power configuration in the second acquisition is based on the result of the first acquisition, that is, the plurality of first signals are obtained, so that when the reflection position with high reflectivity is found, the second power configuration adopted as the second acquisition being acquired is adjusted to reduce the light intensity of the detection light projected to the reflection position with high reflectivity during the second acquisition, thereby effectively avoiding the crosstalk caused by the generation of strong echo light at the reflection position with high reflectivity and effectively improving the optical crosstalk problem between pixels.

Although the present invention is disclosed above, the present invention is not limited thereto. Various changes and modifications may be made by one skilled in the art without departing from the spirit and scope of the invention, and the scope of the invention should be assessed accordingly to that of the appended claims.

Claims

1. A detection method of laser radar is characterized in that,

the laser radar includes: a plurality of light emitting units;

the detection method comprises the following steps: the first acquisition and the second acquisition are carried out sequentially;

wherein the first acquisition comprises: transmitting a plurality of first detection lights in parallel through the plurality of light emitting units in a first power configuration, wherein the first power configuration comprises power of each light emitting unit when the first detection lights are transmitted, and the plurality of first detection lights are in one-to-one correspondence with the plurality of light emitting units; each first detection light is reflected to form corresponding first echo light; receiving the first echo light to obtain a corresponding first signal;

the second acquisition comprises: emitting at least one second probe light in parallel through at least one light emitting unit in a second power configuration, the second power configuration comprising power of each of the light emitting units when emitting the second probe light, the second power configuration comprising: standard power, the said standard power is greater than the power of the correspondent light-emitting unit while transmitting the said first detection light; the second detection light is reflected to form corresponding second echo light; receiving the second echo light to obtain a corresponding second signal; the detection method further comprises the following steps: the second power configuration is obtained based on a plurality of the first signals.

2. The probing method of claim 1, wherein the step of obtaining the second power configuration based on the first signal comprises:

judging whether a light emitting unit emitting first detection light corresponding to the first signal is a first light emitting unit or a second light emitting unit based on the first signal;

when the light-emitting unit emitting the first detection light corresponding to the first signal is judged to be the first light-emitting unit, in the second acquisition process, the power of the first light-emitting unit is the standard power.

3. The probing method of claim 2, wherein the second power configuration further comprises: adjusting power, wherein the adjusting power is smaller than the standard power;

when the light emitting unit emitting the first detection light corresponding to the first signal is judged to be a second light emitting unit, in the second acquisition process, the power of the second light emitting unit is the adjustment power.

4. The method of probing as recited in claim 3 wherein said adjusted power is equal to 0;

the detection method further comprises the following steps: and obtaining the distance information of the reflecting position corresponding to the second transmitting unit based on the first signal.

5. The method of probing as recited in claim 3 wherein said regulated power is greater than 0;

The detection method further comprises the following steps: and obtaining information of the reflection position corresponding to the second transmitting unit based on the first signal and the second signal.

6. The detection method according to claim 3 or 4, wherein the step of determining whether or not the light emitting unit that emits the first detection light corresponding to the first signal is the first light emitting unit based on the first signal includes: comparing the intensity of the first signal with a relative magnitude of a preset threshold; when the intensity of the first signal is smaller than or equal to the preset threshold value, judging that a light emitting unit emitting first detection light corresponding to the first signal is the first light emitting unit; and when the intensity of the first signal is larger than the preset threshold value, judging that the light-emitting unit emitting the first detection light corresponding to the first signal is the second light-emitting unit.

7. The detection method of claim 1, wherein the first acquisition comprises a plurality of measurements, each of the measurements in which each light emitting unit emits a first detection pulse at a corresponding power in the first power configuration, and receives a first echo pulse formed by reflection of the first detection pulse; the second acquisition comprises a plurality of measurements, in each measurement, at least one light emitting unit emits a second detection pulse with corresponding power in the second power, and receives a second echo pulse formed by reflection of the second detection pulse.

8. The method according to claim 7, wherein in each measurement of the first acquisition, the lidar receives an optical signal to obtain corresponding detection data, the detection data including time information and intensity information corresponding to the time information, and accumulates detection data corresponding to each of the plurality of measurements to obtain the first signal;

in each measurement of the second acquisition, the laser radar receives an optical signal to obtain corresponding detection data, wherein the detection data comprises time information and intensity information corresponding to the time information, and the detection data respectively corresponding to the multiple measurements are accumulated to obtain the second signal.

9. A lidar, comprising:

a plurality of light emitting units;

a detection device adapted to carry out the detection method of any one of claims 1 to 8.

10. The lidar of claim 9, wherein the light-emitting unit comprises a vertical-facet laser.

11. The lidar of claim 9 or 10, wherein the lidar comprises an area array detector.

12. The lidar of claim 11, wherein the area array detector comprises: a plurality of receiving units adapted to receive the reflected wave light.

13. The lidar of claim 12, wherein the receiving unit is a geiger-mode based receiving unit.

14. The lidar of claim 13, wherein the receiving unit comprises a plurality of single photon avalanche diodes connected in parallel.