CN111352096B

CN111352096B - Laser radar receiving system and laser radar

Info

Publication number: CN111352096B
Application number: CN202010338399.XA
Authority: CN
Inventors: 胡小波; 沈俭
Original assignee: LeiShen Intelligent System Co Ltd
Current assignee: LeiShen Intelligent System Co Ltd
Priority date: 2020-04-26
Filing date: 2020-04-26
Publication date: 2022-08-09
Anticipated expiration: 2040-04-26
Also published as: CN111352096A

Abstract

The invention discloses a laser radar receiving system, comprising: the photosensitive receiving array surface comprises at least two rows of photosensitive units which are distributed at intervals, each row of photosensitive unit comprises at least two photosensitive elements, two adjacent photosensitive elements in each row of photosensitive units have different photosensitive surface areas, the reflected light spots hit the at least two rows of photosensitive units simultaneously, and at least two photosensitive elements in each row of the hit photosensitive units are hit; the gain selection circuits are connected with the at least two rows of photosensitive units in a one-to-one correspondence mode, and each gain selection circuit is used for determining one of preliminary sampling signals with different gains output by the photosensitive elements of the connected photosensitive units as a target sampling signal and outputting the target sampling signal; and the signal processing circuit is connected with the output ends of the at least two gain selection circuits and is used for multiplying the target sampling signals output by the at least two gain selection circuits to obtain target output signals. The invention also provides a laser radar. The invention can improve the signal-to-noise ratio of the target output signal.

Description

Laser radar receiving system and laser radar

Technical Field

The invention relates to the technical field of laser, in particular to a laser radar receiving system and a laser radar.

Background

In actual work, the laser radar is easily affected by interference light in the environment during detection, and even the problem of abnormal detection of signals occurs when the environmental noise is large, so that how to obtain an output signal with high signal-to-noise ratio is always a problem to be solved in the production process of the laser radar.

The environment that laser radar needs to survey is complicated, and the echo sampled signal intensity that laser radar received differs, in actual work, adopts the same kind of sampled signal gain control mode to echo sampled signal, probably forms saturated sampled signal to some sampled signal magnification overgreat, also can cause the gain not enough to some sampled signal magnification undersize then for the signal noise ratio of output is lower, causes range finding error too big, influences measurement accuracy.

Disclosure of Invention

In view of the above, it is necessary to provide a laser radar receiving system and a laser radar.

A lidar receiving system for receiving a reflected beam of a lidar; the laser radar receiving system includes: the photosensitive receiving array surface comprises at least two columns of photosensitive units which are distributed at intervals, each column of the photosensitive units comprises at least two photosensitive elements, two adjacent photosensitive elements in each column of the photosensitive units have different photosensitive surface areas, the center distance between two adjacent photosensitive units in each column of the photosensitive units is smaller than or equal to a first preset value, and the interval distance between two adjacent photosensitive elements in each column of the photosensitive units is smaller than or equal to a second preset value, so that the reflected light beams projected to the photosensitive receiving array surface hit at least two columns of the photosensitive units at the same time, and at least two photosensitive elements in each column of the photosensitive units hit are hit; the gain selection circuits are connected with the at least two columns of photosensitive units in a one-to-one correspondence mode, and each gain selection circuit is used for determining one of preliminary sampling signals with different gains output by the photosensitive elements of the connected photosensitive units as a target sampling signal and outputting the target sampling signal; and the signal processing circuit is connected with the output ends of the at least two gain selection circuits, performs multiplication processing on the target sampling signals output by the at least two gain selection circuits to obtain target output signals, and outputs the target output signals.

Wherein the lidar receiving system further comprises: the output ends of the gain selection circuits connected with the two adjacent columns of the photosensitive units are respectively connected with different gating switches; the control circuit is connected with the output ends of the at least two gating switches and is used for controlling the gating states of the at least two gating switches according to the predicted positions of the reflected light spots, wherein only one channel of the gated gating switch is opened; the signal processing circuit is connected with the corresponding gain selection circuit through the at least two gating switches, and the signal processing circuit is used for multiplying the target sampling signals output by the at least two gating switches to obtain target output signals and outputting the target output signals.

The distance between the centers of the two adjacent columns of the photosensitive units is less than or equal to half of the maximum length of the reflection light spots in the horizontal direction; and/or photosensitive elements with the same photosensitive surface area in each photosensitive unit are connected in parallel and then are connected with the gain selection circuit through the same channel.

Wherein the gain selection circuit is further configured to: selecting one path of preliminary sampling signal with the intensity within a preset measuring range from the preliminary sampling signals output by the photosensitive unit as the target sampling signal; or selecting one path of preliminary sampling signal in the preliminary sampling signals output by the photosensitive unit according to a preset algorithm to serve as a target sampling signal.

Wherein, the laser radar receiving system further comprises: the output end of a photosensitive element with a larger photosensitive surface area in each row of photosensitive units is connected with one first amplifier; and/or at least two second amplifiers, wherein the output end of each gain selection circuit is connected with one second amplifier.

Wherein, the laser radar receiving system further comprises: the calculating circuit is connected with the output end of the signal processing circuit and is used for calculating parameters according to the target output signal output by the signal processing circuit; the parameter includes at least one of a distance, an orientation, and a speed of the detected object.

A lidar receiving system for receiving a reflected beam of a lidar; the laser radar receiving system includes: the photosensitive receiving array surface comprises at least one row of photosensitive units distributed at intervals, each row of photosensitive units comprises at least two photosensitive elements, two adjacent photosensitive elements in each row of photosensitive units have different photosensitive surface areas, and the interval distance between two adjacent photosensitive elements in each row of photosensitive units is smaller than or equal to a first preset value, so that the reflected light beam projected to the photosensitive receiving array surface hits at least two photosensitive elements in one row of photosensitive units at the same time; and the signal processing circuit comprises at least one multiplier, wherein the at least one multiplier is connected with the at least one row of photosensitive units in a one-to-one correspondence manner and is used for multiplying the preliminary sampling signals output by at least two photosensitive elements in each row of photosensitive units to obtain a target output signal and outputting the target output signal.

Wherein, the laser radar receiving system further comprises: a gating switch connected with the output end of the at least one multiplier; and the control circuit is connected with the gating switch and is used for controlling the gating state of the gating switch according to the predicted position of the reflected light spot, so that only one channel of the gating switch is opened.

A lidar comprising: the laser emission module is used for scanning a target scanning area after producing a laser beam, and an object in the target scanning area reflects the laser beam to obtain a reflected beam; and a laser radar receiving system employing the laser radar receiving system as described above.

The spot size of the laser beam emitted by the laser emitting module is adapted to the first preset value.

The embodiment of the invention has the following beneficial effects:

the adjacent photosensitive elements in each row of photosensitive units have different photosensitive surface areas, so that the photosensitive units have different photosensitive capacities, the initial sampling signals with different gains output by different photosensitive elements are selected to be used as target sampling signals, the signal-to-noise ratio of the target sampling signals can be effectively improved, the reflection light spots of the laser radar hit at least two rows of photosensitive units simultaneously, at least two photosensitive elements in the hit photosensitive units are hit, the gain selection circuits connected with the adjacent two rows of photosensitive units are connected with different gating switches, the target sampling signals with correlation are output by the gating switches, effective signals can be enhanced by performing multiplication operation on the target sampling signals, noise is effectively eliminated, and the signal-to-noise ratio of the output target output signals is improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Wherein:

fig. 1 is a schematic structural diagram of a first embodiment of a laser radar receiving system provided by the present invention;

FIG. 2 is a graph comparing an unmodified signal with an output signal from the lidar receiving system of FIG. 1;

FIG. 3 is a schematic structural diagram of a second embodiment of a lidar receiving system provided by the present invention;

FIG. 4 is a schematic structural diagram of a third embodiment of a lidar receiving system provided by the present invention;

FIG. 5 is a schematic structural diagram of a fourth embodiment of a lidar receiving system provided by the present invention;

fig. 6 is a schematic structural diagram of an embodiment of a lidar provided by the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In actual work, the laser radar is easily affected by interference light in the environment during detection, and even the problem that the signal cannot be normally detected occurs when the environmental noise is large. In addition, echo sampling signals received by the laser radar are different in strength, the same sampling signal gain adjustment mode is adopted for the echo sampling signals, saturated sampling signals can be formed by excessively large amplification factors of some sampling signals, and insufficient gain can be caused by excessively small amplification factors of some sampling signals, so that the signal-to-noise ratio of output signals is low, the ranging error is excessively large, and the measurement precision is influenced.

In this embodiment, in order to solve the above problem, a laser radar receiving system is provided, which can effectively improve the signal-to-noise ratio of a target output signal.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a laser radar receiving system according to a first embodiment of the present invention. The laser radar receiving system 10 provided by the present invention is configured to receive a reflection spot of a laser radar, where the laser radar receiving system 10 includes a photosensitive receiving array 11, and the photosensitive receiving array 11 includes at least two rows of photosensitive units distributed at intervals, which in this embodiment is 8 rows: the

photosensitive unit

111 and 118. In the present embodiment, the photosensitive cells (111-118) in the photosensitive receiving array 11 are distributed at equal intervals. The structures of the light sensing units 111-118 are the same, and the

light sensing units

111 and 112 are taken as examples for illustration herein, so as to avoid redundant description. Each column of photosensitive units includes two photosensitive elements, for example, the photosensitive unit 111 includes

photosensitive elements

1111 and 1112, and the photosensitive unit 112 includes photosensitive elements 1121 and 1122. The areas of the photosensitive surfaces of the two adjacent photosensitive elements are not equal, for example, the area of the photosensitive surface of the photosensitive element 1111 is smaller than that of the photosensitive element 1112, and the area of the photosensitive surface of the photosensitive element 1121 is smaller than that of the photosensitive element 1122. Different photosensitive surface areas have different photosensitivity, that is, for the same reflection light spot, the preliminary sampling signals output by two adjacent photosensitive elements in the same column of photosensitive units have different gains. The central distance between two adjacent rows of photosensitive units is less than or equal to a first preset value, and the spacing distance between two adjacent photosensitive elements in each row of photosensitive units is less than or equal to a second preset value, so that the reflected light beam projected to the light receiving array surface 11 hits the two rows of photosensitive units at the same time, and at least two photosensitive elements in each row of the hit photosensitive units are hit. As shown in fig. 1, the

light sensing units

111 and 112 are simultaneously hit by the reflected light spot. The

photosensitive elements

1111 and 1112 in the photosensitive unit 111 are hit, and the photosensitive elements 1121 and 1122 in the photosensitive unit 112 are hit. In this embodiment, the photosensitive elements in the same row have the same photosensitive area, and in another embodiment, two adjacent photosensitive elements in the same row may have different photosensitive areas.

The lidar receiving system 10 further includes a gain selection circuit 121-. Specifically, the

light sensing elements

1111 and 1112 in the light sensing unit 111 are connected to the gain selection circuit 121 through different paths, respectively, and the light sensing elements 1121 and 1122 in the light sensing unit 112 are connected to the gain selection circuit 122 through different paths, respectively. The gain circuit is used for selecting one of preliminary sampling signals with different gains output by the connected photosensitive units as a target sampling signal and outputting the target sampling signal. For example, the gain circuit 121 selects one of the two preliminary sampling signals output by the light-

sensing elements

1111 and 1112 as the target sampling signal, and the gain selection circuit 122 selects one of the two preliminary sampling signals output by the light-sensing elements 1121 and 1122 as the target sampling signal.

In this implementation scenario, if the reflected light beam is reflected by a target close to the reflected light beam or a target with high reflectivity, the reflected light beam is strong, the areas of the photosensitive surfaces of the photosensitive elements 1111 and 1121 are small, the photosensitive capability is weak, and the intensity of the preliminary sampling signal generated corresponding to the reflected light beam is not too high. If the reflected light beam is reflected by a distant target or an object with low reflectivity, the intensity of the reflected light beam is weak, the photosensitive surfaces of the

photosensitive elements

1112 and 1122 have large areas and strong photosensitive capabilities, and the intensity of the preliminary sampling signal generated corresponding to the reflected light beam is not too low, which is beneficial to improving the signal-to-noise ratio of the sampling signal.

The lidar receiving system 10 further comprises

gating switches

131 and 132, wherein both the

gating switches

131 and 132 are four-to-one switches, the gating switch 131 comprises a passage 1311-. In other embodiments, more gating switches may be provided, which may be the same or different one-out-of-multiple switches, one-out-of-two, one-out-of-three, etc. In this embodiment, the output ends of the gain selection circuits connected to two adjacent columns of light sensing units are respectively connected to different gating switches. For example, the light sensing unit 111 and the light sensing unit 112 are adjacent light sensing units, the gain selection circuit 121 connected to the light sensing unit 111 is connected to the path 1311 of the gate switch 131, and the gain selection circuit 122 connected to the light sensing unit 112 is connected to the path 1321 of the gate switch 132. For another example, the light sensing units 112 and 113 are two adjacent columns of light sensing units, the gain selection circuit 122 connected to the light sensing unit 112 is connected to the path 1321 of the gate switch 132, and the gain selection circuit 123 connected to the light sensing unit 113 is connected to the path 1312 of the gate switch 131.

Lidar receiving system 10 also includes a control circuit 14. The control circuit 14 is connected to the two

gate switches

131 and 132 for controlling the gate states of the two

gate switches

131 and 132. In this embodiment, the control circuit 14 is connected to the laser emitting module corresponding to the reflected light beam (including wired connection and wireless connection), and can obtain parameters such as the angle of the laser emission, the size and the shape of the reflected light spot, and according to the parameters, the position of the reflected light spot on the photosensitive receiving front 11 can be calculated in advance, so as to determine at least two columns of photosensitive units to be hit, and according to the at least two columns of photosensitive units, the

gating switches

131 and 132 are controlled to open corresponding paths. For example, in the scenario shown in fig. 1, the control circuit 14 calculates in advance that the light-

sensing units

111 and 112 will be hit by the reflected light spot, and then controls the path 1311 of the gating switch 131 to be opened and the path 1321 of the gating switch 132 to be opened, so that the

gating switches

131 and 132 can output two paths of target sampling signals with correlation.

The gating switch only opens one path to receive the signals of the photosensitive units at the same time, and the central distance of each row of photosensitive units can be adjusted according to the precision requirement of operation, so that the number of rows of photosensitive units simultaneously hit by the reflected light spots is less than or equal to the number of the gating switches, and the problem that at least one path of signals cannot be transmitted because multiple rows of photosensitive units corresponding to the same gating switch are hit by the reflected light spots at the same time is avoided.

Lidar receiving system 10 also includes signal processing circuitry 15. The signal processing circuit 15 is connected to the two

gate switches

131 and 132, receives the target sampling signals output by the two

gate switches

131 and 132, multiplies the two target sampling signals to obtain a target output signal, and outputs the target output signal. As can be seen from the above description, the target sampling signal output by the gating switch 131 corresponds to the light pulse received by the light sensing unit 111, the target sampling signal output by the gating switch 132 corresponds to the light pulse received by the light sensing unit 112, and the light pulse received by the light sensing unit 111 and the light pulse received by the light sensing unit 112 correspond to the same reflected light spot, so that the target sampling signal output by the gating switch 131 and the target sampling signal output by the gating switch 132 have correlation. Therefore, when the two paths of signals are subjected to multiplication, effective signals (relevant partial signals) in the two paths of signals are amplified, and noises with different sizes (irrelevant partial signals) are reduced or smoothed, so that the effective signals which are originally submerged by the noises can be reserved and enhanced.

In this embodiment, the signal processing circuit 15 includes a multiplier, two input terminals of which are respectively connected to the output terminals of the two

gating switches

131 and 132, and receives the target sampling signals output by the two

gating switches

131 and 132, and multiplies the two target sampling signals.

In another implementation scenario, when only one of the two

gating switches

131 and 132 outputs the target sampling signal and the other does not output the target sampling signal or outputs only noise, for example, path 1311 of gating switch 131 is open and path 1321 of gating switch 132 is open. If the position of the reflected light spot exceeds the photosensitive receiving front 11 and only hits the edge of the photosensitive unit 111, the signal output from the path 1321 of the gate switch 132 may only have noise, and the target sampling signal corresponding to the reflected light spot (the target sampling signal output from the path 1321 of the gate switch 132) may be smoothed as an interference signal by the multiplication operation of the signal processing circuit 15.

Referring to fig. 2, fig. 2 is a comparison graph of an unamended signal and an output signal of the lidar receiving system shown in fig. 1, and it can be seen from fig. 2 that the signal-to-noise ratio is greatly improved, which is beneficial to identifying an effective optical signal from noise, thereby ensuring the detection accuracy.

It can be known from the above description that in this embodiment, adjacent photosensitive elements in each row of photosensitive units have different photosensitive surface areas, and thus have different photosensitive capabilities, and a preliminary sampling signal with different gains output by different photosensitive elements is selected as a target sampling signal with appropriate gain, which can effectively improve the signal-to-noise ratio of the target sampling signal.

In another embodiment, the gating switch and the control circuit for controlling the gating switch to be turned on may not be provided, the output terminal of the gain selection circuit is directly connected to the signal processing circuit, and the signal processing circuit performs multiplication processing on the sampling signal output by the gain selection circuit. Interference signals generated in the environment have no correlation, so that the interference signals can be effectively eliminated after multiplication processing.

Please continue to refer to fig. 1. In this embodiment, the size and shape of the reflected light spot are known, and therefore the distance in the horizontal direction of the reflected light spot can be obtained. In the scene shown in fig. 1, the reflection light spot is a circle, and the distance in the horizontal direction of the reflection light spot is the diameter of the circle, and in other implementation scenes, the reflection light spot may be in other shapes such as an ellipse and a square, and may even be an irregular figure. The center pitch of two adjacent columns of photosensitive units (e.g., the photosensitive unit 111 and the photosensitive unit 112, the photosensitive unit 112 and the photosensitive unit 113) is set according to the distance in the horizontal direction of the reflection spot so that the center pitch is smaller than half of the distance in the horizontal direction of the reflection spot. So that the reflected light spot can simultaneously hit at least two photosensitive units located in different columns. In this embodiment, the

photosensitive units

111 and 118 are movably mounted on the photosensitive receiving front 11, and can be flexibly adjusted according to the distance in the horizontal direction of the reflected light spot to be received. In other implementation scenarios, the spot size may also be adjusted according to the designed center-to-center distance between two adjacent columns of photosensitive units (e.g., the photosensitive unit 111 and the photosensitive unit 112, the photosensitive unit 112 and the photosensitive unit 113).

Further, the interval pitch between the adjacent two photosensitive elements (for example, the

photosensitive elements

1111 and 1112 or the photosensitive elements 1121 and 1122) in each column of photosensitive units is set according to the distance in the vertical direction of the reflection spot so that the interval pitch is smaller than half of the distance in the vertical direction of the reflection spot, so that the reflection spot can simultaneously hit at least two adjacent photosensitive elements (for example, the

photosensitive elements

1111 and 1112 or the photosensitive elements 1121 and 1122) in each column of photosensitive units. In this embodiment, the photosensitive elements (e.g., 1111, 1112, 1121, 1122, etc.) are movably mounted on the photosensitive receiving array 11, and can be flexibly adjusted according to the distance in the vertical direction of the reflected light spot to be received. In other implementation scenarios, the light spot size may also be adjusted according to the designed spacing distance between two adjacent light-sensing elements (e.g., light-

sensing elements

1111 and 1112 or light-sensing elements 1121 and 1122) in each column of light-sensing units.

As can be seen from the above description, in this embodiment, the distance between the centers of two adjacent columns of photosensitive units is set to be less than or equal to half of the maximum length of the reflection light spot in the horizontal direction, so that the reflection light spot simultaneously hits at least two photosensitive units located in different columns, and the distance between two adjacent photosensitive elements in each column of photosensitive units is set to be half of the maximum length of the reflection light spot in the vertical direction, so that the reflection light spot can simultaneously hit at least two photosensitive elements in one column of photosensitive units.

Referring to fig. 1, the reflected light beam irradiates the light spots formed by the light receiving front 11 and hits the

light sensing elements

1111 and 1112 of the light sensing unit 111 and the light sensing elements 1121 and 1122 of the light sensing unit 112. If the reflected light beam is reflected by a closer target or a target with high reflectivity, the reflected light beam is strong, the photosensitive areas of the photosensitive elements 1111 and 1121 are small, the photosensitive capability is weak, and the intensity of the preliminary sampling signal generated corresponding to the reflected light beam is not too high. The photosensitive areas of the

photosensitive elements

1112 and 1122 are large, the photosensitive capability is strong, and the intensity of the preliminary sampling signal generated corresponding to the reflected light beam may be too strong, so that a saturated sampling signal is easily generated, and the measurement result is affected. Therefore, if the reflected light beam is reflected by a distant target or an object with low reflectivity, the intensity of the reflected light beam is weak, the photosensitive areas of the

photosensitive elements

1112 and 1122 are large, the photosensitive capability is strong, and the intensity of the preliminary sampling signal generated corresponding to the reflected light beam is not too low, which is beneficial to improving the signal-to-noise ratio of the sampling signal. The photosensitive areas of the photosensitive elements 1111 and 11211 are small, the photosensitive capability is weak, the intensity of the preliminary sampling signal generated corresponding to the reflected light beam may be too low, the intensity of the effective sampling signal may be lower than the noise intensity, and the signal-to-noise ratio is too low, so that the measurement error is too large.

Therefore, when the reflected light beam is strong, the gain selection circuit 121 selects the preliminary sampling signal output by the light sensing element 1111 in the light sensing unit 111 as the target sampling signal, and the gain selection circuit 122 selects the preliminary sampling signal output by the light sensing element 1121 in the light sensing unit 112 as the target sampling signal. When the reflected light beam is weak, the gain selection circuit 121 selects the preliminary sampling signal output by the photosensitive element 1112 in the photosensitive cell 111 as the target sampling signal, and the gain selection circuit 122 selects the preliminary sampling signal output by the photosensitive element 1122 in the photosensitive cell 112 as the target sampling signal.

Specifically, the gain selection circuit 121-. For example, the

gain selection circuit

121 and 128 may select at least one preliminary sampling signal whose signal-to-noise ratio meets a predetermined requirement, or the

gain selection circuit

121 and 128 may select at least one preliminary sampling signal according to the distance of the target and the reflectivity of the target. In other implementation scenarios, the gain selection circuits 121 to 28 select at least one preliminary sampling signal with a signal intensity within a preset measurement range from the two preliminary sampling signals, so that selection of a saturated sampling signal with an excessively high amplification factor or a sampling signal with an insufficient gain can be effectively avoided.

As can be seen from the above description, in this embodiment, the gain selection circuit selects one of the two paths of preliminary sampling signals generated by the photosensitive elements in the connected photosensitive units as the target sampling signal, and can select the preliminary sampling signal with moderate signal strength as the target sampling signal, thereby effectively improving the signal-to-noise ratio of the target output signal generated according to the target sampling signal.

Referring to fig. 3, fig. 3 is a schematic structural diagram of a laser radar receiving system according to a second embodiment of the present invention. The laser radar receiving system 20 includes a photosensitive receiving front 21, a

gain selection circuit

221 and 228, gate switches 231 and 232, a control circuit 24, and a signal processing circuit 25. The gain selection circuit 221-.

The photosensitive receiving array 21 includes photosensitive cells 211-218, each column of photosensitive cells includes 3 photosensitive elements. The structures of the

light sensing units

211 and 218 are the same, and the

light sensing units

211 and 212 are taken as examples for illustration, so as to avoid redundant description. The photosensitive unit 211 includes

photosensitive elements

2111, 2112, and 2113, and the photosensitive unit 212 includes

photosensitive elements

2121, 2122, and 2123. The distance between the centers of two adjacent columns of photosensitive units is smaller than or equal to a first preset value, and the distance between the 3 photosensitive elements in each column of photosensitive units is smaller than or equal to a second preset value, so that the reflected light beam irradiates the reflected light spot formed by the photosensitive receiving front 21 and simultaneously hits at least two photosensitive units in different columns. As shown in fig. 3, the reflected light spot simultaneously hits the

photosensitive elements

2111, 2112, and 2113 in the photosensitive unit 211 and the

photosensitive elements

2121, 2122, and 2123 in the photosensitive unit 212. The

photosensitive elements

2111 and 2113 have the same photosensitive surface area and the same photosensitive capability, and the photosensitive surface area of the photosensitive element 2112 is larger than that of the

photosensitive elements

2111 and 2113, so that the photosensitive element has stronger photosensitive capability. The

photoreceptors

2121 and 2123 have the same size and the same photoreceptive capacity, and the photoreceptor 2122 has a larger photoreceptor surface area than the

photoreceptors

2121 and 2123 and therefore has a greater photoreceptor capacity.

The photosensitive elements with the same photosensitive surface area and positioned in the same row of photosensitive units are connected in parallel and then are connected with the corresponding gain selection circuit through the same channel. For example, the

photosensitive elements

2111 and 2113 in the photosensitive unit 211 are connected in parallel to the gain selection circuit 221 through the same channel, and the photosensitive element 2112 is connected to the gain selection circuit 221 through another channel. The

photoreceptors

2121 and 2123 in the photoreceptor unit 212 are connected in parallel and then connected to the gain selection circuit 222 through the same channel, and the photoreceptor 2122 is connected to the gain selection circuit 222 through another channel.

In the scenario shown in fig. 3, the preliminary sampling signals generated by the

photoreceptors

2111 and 2113 are superimposed and input to the gain selection circuit 221, and the preliminary sampling signals generated by the

photoreceptors

2121 and 2123 are superimposed and input to the gain selection circuit 222. The photosensitive elements with the same photosensitivity are connected in parallel, so that the superposition of preliminary sampling signals of the photosensitive elements is realized, and the problems of insufficient signal intensity or low signal-to-noise ratio caused by weak photosensitivity can be effectively avoided.

In other embodiments, the reflected light spot may only hit two photo-sensors in each column of photo-sensor units, such as photo-

sensors

2111 and 2112 in the photo-sensor unit 211 and photo-

sensors

2121 and 2122 in the photo-sensor unit 212, and since the photo-

sensors

2111 and 2113 are connected in parallel, the path between the photo-sensor 2111 and the gain selection circuit 221 is still conducting, and similarly, since the photo-

sensors

2121 and 2123 are connected in parallel, the path between the photo-sensor 2121 and the gain selection circuit 222 is conducting. The gain circuit 221 selects one of the two preliminary sampling signals output from the light-

sensing elements

2111 and 2112 as a target sampling signal, and the gain selection circuit 222 selects one of the two preliminary sampling signals output from the light-

sensing elements

2121 and 2122 as a target sampling signal.

According to the above description, in this embodiment, the photosensitive elements with the same photosensitivity are connected in parallel, so that the superposition of the preliminary sampling signals of the photosensitive elements is realized, and the problems of insufficient signal strength or low signal-to-noise ratio due to weak photosensitivity can be effectively avoided.

Referring to fig. 4, fig. 4 is a schematic structural diagram of a laser radar receiving system according to a third embodiment of the present invention. The laser radar receiving system 30 includes a photosensitive receiving array 31, a

gain selection circuit

321 and 328, gating switches 331 and 332, a control circuit 34, and a signal processing circuit 35. The photosensitive receiving array surface 31, the gain selection circuit 321-.

The photosensitive receiving array 31 includes photosensitive units 311-318, and each row of photosensitive units includes 2 photosensitive elements with unequal photosensitive surface areas. The structures of the photosensitive units are the same, and the

photosensitive units

311 and 312 are taken as examples for explanation here to avoid redundant description.

The lidar receiving system 30 further includes a plurality of

first amplifiers

361 and 368, and an output end of the photosensitive element with a larger photosensitive surface area in each row of photosensitive units is connected with one first amplifier. Specifically, the photosensitive element 3112 of the photosensitive unit 311 has a large photosensitive surface area and is connected to the first amplifier 361, and the photosensitive element 3122 of the photosensitive unit 312 has a large photosensitive surface area and is connected to the first amplifier 362. In other implementation scenarios, if at least two photosensitive elements with larger photosensitive surface areas exist in each row of photosensitive units, the at least two photosensitive elements are connected in parallel and then connected with the first amplifier corresponding to the photosensitive unit through the same channel. The first amplifier 361-368 is used for amplifying the preliminary sampling signal output by the photosensitive element with a larger photosensitive surface area in the photosensitive unit 311-318. The first amplifier 361-368 is disposed close to the photosensitive cell 311-318, so as to effectively reduce the noise in the amplified sampling signal.

Lidar receiving system 30 also includes a plurality of second amplifiers 371 and 378. The second amplifier 371 and 378 are connected to the

gain selection circuit

321 and 328 in a one-to-one correspondence, for example, the input terminal of the second amplifier 371 is connected to the output terminal of the gain selection circuit 321, and the input terminal of the second amplifier 372 is connected to the output terminal of the gain selection circuit 322. The second amplifier 371-378 is used to amplify the target sampling signal outputted from the gain selection circuit 321-328 to enhance the signal strength thereof.

Lidar receiving system 30 also includes a computing circuit 38. The calculation circuit 38 is connected to the signal processing circuit 35, and performs parameter calculation including at least one parameter of the distance, the orientation, and the speed of the detected object, based on the target output signal output from the signal processing circuit 35.

It can be known through the above description that, in this embodiment, the photosensitive element with the larger photosurface area in the photosensitive unit is connected with the first amplifier, can amplify preliminary sampling signal when the reflected light beam intensity is weaker, the reflected light beam that the received light intensity is weaker that can be better, connect the second amplifier at the output of gain selection circuit, can amplify target sampling signal, can be favorable to promoting the signal-to-noise ratio of the target output signal who reachs according to target sampling signal.

Referring to fig. 5, fig. 5 is a schematic structural diagram of a laser radar receiving system according to a fourth embodiment of the present invention. The laser radar receiving system 40 provided by the present invention is configured to receive a reflection spot of a laser radar, where the laser radar receiving system 40 includes a photosensitive receiving array surface 41, and the photosensitive receiving array surface 41 includes at least one row of photosensitive units distributed at equal intervals, which is 8 rows in this embodiment: photo sensing unit 411-418. The structures of the photo-sensing units 411-418 are the same, and the photo-sensing units 411-412 are taken as an example for illustration, so as to avoid redundant description.

Each column of photosensitive cells includes two photosensitive elements, for example, the photosensitive cell 411 includes

photosensitive elements

4111 and 4112, and the photosensitive cell 412 includes

photosensitive elements

4121 and 4122. The photosensitive surface areas of two adjacent photosensitive elements are not equal, for example, the photosensitive surface area of the photosensitive element 4111 is smaller than that of the photosensitive element 4112, and the photosensitive surface area of the photosensitive element 4121 is smaller than that of the photosensitive element 4122. Different photosensitive surface areas have different light sensing capacities, namely, for the same reflection light spot, the preliminary sampling signals output by two adjacent light sensing elements in the same column of light sensing units have different gains. The spacing distance between two adjacent photosensitive elements in each row of photosensitive units is less than or equal to a first preset value, so that the reflected light beam projected to the reflected light spot of the photosensitive receiving front 41 simultaneously hits at least two photosensitive elements in one row of photosensitive units. As shown in fig. 4, the

photosensitive elements

4111 and 4112 in the photosensitive unit 411 are hit. It should be noted that, the term "hitting the photosensitive elements" as used herein means that the light spots can fall on each photosensitive element, and the light spots may completely cover all the photosensitive elements or only cover the area of the photosensitive elements.

In this implementation scenario, if the reflected light beam is reflected by a closer target or a target with a high reflectivity, the reflected light beam is stronger, the area of the photosurface of the photosensing element 4111 is small, the photosensing capability is weaker, and the strength of the preliminary sampling signal generated by the corresponding reflected light beam is not too high. If the reflected light beam is reflected by a distant target or an object with low reflectivity, the intensity of the reflected light beam is weak, the area of the photosensitive surface of the photosensitive element 4112 is large, the photosensitive capability is strong, the intensity of the preliminary sampling signal generated corresponding to the reflected light beam is not too low, and the signal-to-noise ratio of the sampling signal is favorably improved. Regardless of the intensity of the reflected light beam, the ratio of valid signals in the preliminary sampling signal output by at least one photosensitive element (4111 or 4112) in the photosensitive unit 411 is high.

The laser radar receiving system 40 further comprises a signal processing circuit 42, wherein the signal processing circuit 42 comprises

multipliers

421 and 428, which are connected with the

photosensitive units

411 and 418 in a one-to-one correspondence manner, and are used for performing multiplication processing on the received preprocessing signals to obtain target output signals and outputting the target output signals. For example, in the scene shown in fig. 4, the

photo sensing elements

4111 and 4112 in the photo sensing unit 411 are hit by the same reflected light spot, the

photo sensing elements

4111 and 4112 generate two preliminary sampling signals, respectively, and the two preliminary sampling signals are input to the multiplier 421, and because the two preliminary sampling signals have correlation, the two signals amplify effective signals (related partial signals) therein when performing multiplication, and reduce or smooth out noises (irrelevant partial signals) with different sizes, so that the effective signals originally submerged by the noises can be retained and enhanced. Since the two paths of preliminary sampling signals generated by the

photosensitive elements

4111 and 4112 respectively have a large proportion of effective signals in at least one path of preliminary sampling signal, it can be avoided that the signal-to-noise ratio of the output target output signal is low due to the low proportion of effective signals in the two paths of preliminary sampling signals when multiplication is performed.

It can be known from the above description that, in this embodiment, the preliminary sampling signals output by two adjacent photosensitive elements in the same line of photosensitive units have different gains, at least one path of the preliminary sampling signals generated by the at least two photosensitive elements has a higher effective signal occupancy ratio, and the at least two paths of preliminary sampling signals with correlation are preprocessed and then multiplied, so that the effective signals can be effectively enhanced, and the signal-to-noise ratio of the output target output signal is improved.

With continued reference to fig. 5, the lidar receiving system 40 further includes a gating switch 43, where the gating switch 43 is a one-out-of-many switch including the

paths

431 and 438, and only one path of the gating switch 43 is in the on state at the same time, and the other paths are in the off state. The

multipliers

421 and 428 in the signal processing circuit 42 are connected to the paths of the gate switch 43 in a one-to-one correspondence, for example, the multiplier 421 is connected to the path 431, the multiplier 422 is connected to the path 432, and so on.

Lidar receiving system 40 also includes a control circuit 44. The control circuit 44 is connected to the gate switch 43, and controls the gate state of the gate switch 43. In this embodiment, the control circuit 4 is connected to the laser emitting module corresponding to the reflected light beam (including wired connection and wireless connection), and can obtain parameters such as the angle of the laser emission, the size and the shape of the reflected light spot, and calculate the position of the reflected light spot on the photosensitive receiving front 41 in advance according to the parameters, thereby determining at least one row of photosensitive units to be hit, and controlling the gate switch 43 to open the corresponding path according to the row of photosensitive units.

For example, in the scenario shown in fig. 4, the control circuit 44 calculates in advance that the light-sensing unit 411 will be hit by the reflected light spot, and controls the path 431 of the gate switch 43 to be opened, so that the target output signal processed by the multiplier 421 can be output.

As can be seen from the above description, in the present embodiment, by providing the gate switch and the control circuit, the target output signal can be accurately obtained.

Referring to fig. 6, fig. 6 is a schematic structural diagram of a laser radar according to an embodiment of the present invention. The laser radar 50 provided by the present invention comprises a laser emission module 51 and a laser radar receiving system 52, wherein the laser radar receiving system 52 comprises the laser radar receiving systems shown in fig. 1, 3-5.

As shown in fig. 6, the laser emitting module 51 is used for generating a laser beam and scanning the laser beam to a target scanning area, an object in the target scanning area reflects the laser beam to obtain a reflected beam, and 61 and 62 are reflected spots of the reflected beam projected to the laser radar receiving system 52. As can be seen from the above description, the lidar receiving system 52 includes a photosensitive receiving array, where the photosensitive receiving array includes at least two rows of photosensitive units distributed at equal intervals, each row of photosensitive units includes at least two photosensitive elements, two adjacent photosensitive elements in each row of photosensitive units have different photosensitive surface areas, a center distance between two adjacent rows of photosensitive units is less than or equal to a first preset value, an interval distance between two adjacent photosensitive elements in each row of photosensitive units is less than or equal to a second preset value, and a size of a reflection spot (e.g., the reflection spots 61 and 62) of the laser beam emitted by the laser emission module 51 is adapted to the first preset value and the second preset value, so that the reflection spot 61 or the reflection spot 62 can hit at least two rows of photosensitive units at the same time, and at least two photosensitive elements in each row of photosensitive units hit are hit.

The laser radar receiving system 52 further includes at least two gain selection circuits, which are connected to the at least two columns of light-sensing units in a one-to-one correspondence manner, and each gain selection circuit is configured to determine one of preliminary sampling signals with different gains, which are output from the light-sensing elements of the connected light-sensing units, as a target sampling signal and output the target sampling signal.

The lidar receiving system 52 further comprises at least two gating switches, and the output ends of the gain selection circuits connected with two adjacent columns of light sensing units are respectively connected with different gating switches.

The lidar receiving system 52 further comprises a control circuit connected to the output terminals of the at least two gating switches for controlling the gating state of each gating switch according to the predicted position of the reflected light spot, wherein only one channel of the gated gating switch is opened.

The lidar receiving system 52 further includes a signal processing circuit, which is connected to the at least two gate switches, and performs multiplication processing on the target sampling signals output by the at least two gate switches to obtain a target output signal, and outputs the target output signal.

At least two photosensitive elements in the same photosensitive unit generate at least two paths of preliminary sampling signals with different gains after being hit by the same reflection light spot (such as the reflection light spot 61 or 62), at least one path of preliminary sampling signal with proper gain exists no matter the intensity of the reflection light beam, and the gain selection circuit selects the preliminary sampling signal as a target sampling signal, so that the problem that the signal-to-noise ratio of the target output signal is low due to overhigh or overlow signal intensity when the target output signal is obtained according to the target sampling signal can be avoided.

At least two photosensitive units are hit by the same reflected light spot, the target sampling signals output by the corresponding gain selection circuits have correlation, the delay difference of the at least two target sampling signals is small, the at least two target sampling signals are subjected to multiplication processing, effective signals with correlation can be enhanced, noise without correlation can be eliminated, and therefore the effective signals which are originally submerged by the noise can be reserved and enhanced.

Further, in order to improve the receiving effect of laser radar receiving system 52, laser radar 50 further includes a receiving lens 53, where receiving lens 53 is configured to receive the reflected light beam, so that the reflected light beam can irradiate onto the photosensitive receiving front of laser radar receiving system 52.

It can be known from the above description that, in the lidar receiving system of the lidar in this embodiment, adjacent photosensitive elements in each row of photosensitive units have different photosensitive surface areas, and thus have different photosensitive capacities, a proper gain is selected as a target sampling signal from preliminary sampling signals with different gains output by different photosensitive elements, which can effectively improve the signal-to-noise ratio of the target sampling signal, a reflection light spot of the lidar hits at least two rows of photosensitive units simultaneously, gain selection circuits connected to two adjacent rows of photosensitive units are connected to different gate switches, each gate switch outputs a target sampling signal with correlation, performing multiplication operation on these target sampling signals can enhance effective signals, effectively eliminate noise, and thus improve the signal-to-noise ratio of the output target output signal.

Different from the prior art, the method has the advantages that the reflected light spots hit at least two rows of photosensitive units simultaneously, at least two photosensitive elements with unequal photosensitive surface areas in the photosensitive units are hit, the initial sampling signals with different gains output by different photosensitive elements are selected as target sampling signals with proper gains, the signal-to-noise ratio of the target sampling signals can be effectively improved, the reflected light spots of the laser radar hit at least two rows of photosensitive units simultaneously, the gain selection circuits connected with two adjacent rows of photosensitive units are connected with different gating switches, the gating switches output the target sampling signals with the correlation, the effective signals can be enhanced by multiplying the target sampling signals, the noise is effectively eliminated, and the signal-to-noise ratio of the output target output signals is improved.

The above disclosure is only for the purpose of illustrating the preferred embodiments of the present invention, and it is therefore to be understood that the invention is not limited by the scope of the appended claims.

Claims

1. A lidar receiving system configured to receive a reflected beam of a lidar;

the laser radar receiving system includes:

the photosensitive receiving array surface comprises at least two columns of photosensitive units which are distributed at intervals, each column of the photosensitive units comprises at least two photosensitive elements, the adjacent two photosensitive elements in each column of the photosensitive units have different photosensitive surface areas, the central distance between the adjacent two columns of the photosensitive units is smaller than or equal to a first preset value, and the interval distance between the adjacent two photosensitive elements in each column of the photosensitive units is smaller than or equal to a second preset value, so that the reflected light spots projected to the photosensitive receiving array surface hit at least two columns of the photosensitive units at the same time, and at least two photosensitive elements in each column of the photosensitive units hit;

the gain selection circuits are connected with the at least two columns of photosensitive units in a one-to-one correspondence mode, and each gain selection circuit is used for determining one of preliminary sampling signals with different gains output by the photosensitive elements of the connected photosensitive units as a target sampling signal and outputting the target sampling signal;

and the signal processing circuit is connected with the output ends of the at least two gain selection circuits, performs multiplication processing on the target sampling signals output by the at least two gain selection circuits to obtain target output signals, and outputs the target output signals.

2. The lidar receiving system of claim 1, further comprising:

the output ends of the gain selection circuits connected with the two adjacent columns of the photosensitive units are respectively connected with different gating switches;

the control circuit is connected with the output ends of the at least two gating switches and is used for controlling the gating states of the at least two gating switches according to the predicted positions of the reflected light spots, wherein only one channel of the gated gating switch is opened;

the signal processing circuit is connected with the corresponding gain selection circuit through the at least two gating switches, and the signal processing circuit is used for multiplying the target sampling signals output by the at least two gating switches to obtain target output signals and outputting the target output signals.

3. The lidar receiving system according to claim 1, wherein a center-to-center distance between two adjacent columns of the light sensing units is less than or equal to half of a maximum length of the reflection light spots in a horizontal direction; and/or

And photosensitive elements with the same photosensitive surface area in each photosensitive unit are connected in parallel and then are connected with the gain selection circuit through the same channel.

4. The lidar receiving system of claim 1, wherein the gain selection circuit is further configured to:

selecting one path of preliminary sampling signal with the intensity within a preset measurement range from the preliminary sampling signals output by the photosensitive unit as the target sampling signal; or the like, or, alternatively,

and selecting one path of preliminary sampling signals in the preliminary sampling signals output by the photosensitive unit as target sampling signals according to a preset algorithm.

5. The lidar receiving system of claim 1, further comprising:

the output end of a photosensitive element with a larger photosensitive surface area in each row of photosensitive units is connected with one first amplifier; and/or

And the output end of each gain selection circuit is connected with one second amplifier.

6. The lidar receiving system of claim 1, further comprising:

the calculating circuit is connected with the output end of the signal processing circuit and is used for calculating parameters according to the target output signal output by the signal processing circuit; the parameter includes at least one of a distance, an orientation, and a speed of the detected object.

7. A lidar receiving system configured to receive a reflected beam of a lidar;

the laser radar receiving system includes:

the photosensitive receiving array surface comprises at least one row of photosensitive units distributed at intervals, each row of photosensitive units comprises at least two photosensitive elements, two adjacent photosensitive elements in each row of photosensitive units have different photosensitive surface areas, and the interval distance between two adjacent photosensitive elements in each row of photosensitive units is smaller than or equal to a first preset value, so that the reflected light beam projected to the photosensitive receiving array surface hits at least two photosensitive elements in one row of photosensitive units at the same time;

and the signal processing circuit comprises at least one multiplier, wherein the at least one multiplier is connected with the at least one row of photosensitive units in a one-to-one correspondence manner and is used for multiplying the preliminary sampling signals output by at least two photosensitive elements in each row of photosensitive units to obtain a target output signal and outputting the target output signal.

8. The lidar receiving system of claim 7, further comprising:

a gating switch connected with the output end of the at least one multiplier;

and the control circuit is connected with the gating switch and is used for controlling the gating state of the gating switch according to the predicted position of the reflected light spot, so that only one channel of the gating switch is opened.

9. A lidar, comprising:

the laser emission module is used for scanning a target scanning area after producing a laser beam, and an object in the target scanning area reflects the laser beam to obtain a reflected beam; and

a lidar receiving system according to any of claims 1 to 8.

10. The lidar of claim 9, wherein a spot size of the laser beam emitted by the lasing module is adapted to the first predetermined value.