CN110940988B - Laser radar receiving system and laser radar - Google Patents
Laser radar receiving system and laser radar Download PDFInfo
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- CN110940988B CN110940988B CN201911059970.8A CN201911059970A CN110940988B CN 110940988 B CN110940988 B CN 110940988B CN 201911059970 A CN201911059970 A CN 201911059970A CN 110940988 B CN110940988 B CN 110940988B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
- G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
- G01S7/481—Constructional features, e.g. arrangements of optical elements
- G01S7/4816—Constructional features, e.g. arrangements of optical elements of receivers alone
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Abstract
The embodiment of the invention discloses a laser radar receiving system, which comprises: the photosensitive receiving array surface comprises at least two rows of photosensitive units which are distributed at equal intervals, and the center distance between every two adjacent rows of photosensitive units is smaller than or equal to a preset value, so that the reflected light beams projected to the photosensitive receiving array surface hit at least two photosensitive units in different rows at the same time; at least two gating switches, wherein two adjacent columns of light sensing units are respectively connected with different gating switches; the control circuit is connected with the at least two gating switches and used 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; and the signal processing circuit is connected with the at least two gating switches, performs multiplication processing on signals output by the at least two gating switches to obtain a target signal, and outputs the target signal. The invention also provides a laser radar. The invention can effectively eliminate noise and enhance effective signals, thereby improving the signal-to-noise ratio of target signals.
Description
Technical Field
The invention relates to the technical field of laser, in particular to a laser radar receiving system and a laser radar.
Background
The radar system of the laser radar for emitting laser beams to detect characteristic quantities such as the position, the speed and the like of a target is widely applied to the field of automatic driving. The working principle is that a detection signal (laser beam) is transmitted to a target, then a received signal (target echo) reflected from the target is compared with the transmitted signal, and after appropriate processing, relevant information of the target, such as target distance, direction, height, speed, attitude, even shape and other parameters, can be obtained, so that the target is detected, tracked and identified.
In actual work, the laser radar is easily affected by interference light in the environment, and even the problem that the signal cannot be normally detected occurs when the environmental noise is large, so that how to obtain an output signal with high signal-to-noise ratio is always the problem to be solved in the laser radar production process.
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 system comprises: the photosensitive receiving array surface comprises at least two rows of photosensitive units which are distributed at equal intervals, and the center distance between every two adjacent rows of photosensitive units is smaller than or equal to a preset value, so that the reflected light beams projected to the reflective light spots of the photosensitive receiving array surface simultaneously hit at least two photosensitive units in different rows; the two adjacent columns of the light sensing units are respectively connected with different gating switches; the control circuit is connected with the at least two gating switches and used 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; and the signal processing circuit is connected with the at least two gating switches, performs multiplication processing on signals output by the at least two gating switches to obtain a target signal, and outputs the target signal.
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.
The photosensitive unit of each column comprises a plurality of photosensitive elements, and the plurality of photosensitive elements of each column are connected in parallel.
The signal processing circuit comprises at least one primary multiplier, two input ends of each primary multiplier are respectively connected with the output ends of two adjacent columns of the photosensitive units, and each column of the photosensitive units is only connected with one primary multiplier.
The signal processing circuit further comprises at least one secondary multiplier, and at least one input end of the at least one secondary multiplier is connected with an output end of the at least one primary multiplier.
Wherein the signal processing circuit comprises a multi-stage multiplier; the output end of each gating switch is connected to one input end of the corresponding multiplier; the output ends of any two multipliers are connected with the input end of a next multiplier so as to multiply the output result of the previous multiplier for the second time until only one output of the next multiplier is obtained.
The number of the gating switches is larger than or equal to the number of the columns of the photosensitive units simultaneously hit by the reflection light spots.
Wherein, the laser radar receiving system further comprises: each amplifier is connected between the output end of one row of photosensitive units and the gating switch connected with the output end of the photosensitive unit and is used for amplifying the output signals of the photosensitive units; or each of the amplifiers is disposed between the output terminal of each gate switch and the signal processing circuit.
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.
And the spot size of the laser beam emitted by the laser emitting module is adapted to the preset value.
The embodiment of the invention has the following beneficial effects:
the center distance between two adjacent columns of photosensitive units of the photosensitive receiving array surface is smaller than or equal to a preset value, so that the reflected light spots of the laser radar hit at least two photosensitive units located in different columns at the same time, the two adjacent columns of photosensitive units are connected with different gating switches, signals output by the gating switches correspond to the same reflected light spot, correlation is achieved, at least two paths of related signals are subjected to multiplication operation, effective signals corresponding to the same reflected light spot are enhanced, noise without correlation is eliminated, and the signal-to-noise ratio of output target 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. 1a is a schematic structural diagram of a first embodiment of a lidar receiving system provided by the present invention;
FIG. 1b is a graph comparing an unmodified signal with an output signal from the lidar receiving system of FIG. 1 a;
FIG. 2 is a schematic structural diagram of an embodiment of a row of light-sensing units in the lidar receiving system provided by the present invention;
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 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 the receiving system of the off-axis laser radar, because the light spot continuously moves on the photosensitive receiving array surface, the position of the photosensitive receiving array surface receiving the effective light echo is always in change. The time delay of the signals of a plurality of channels of the photosensitive receiving array surface reaching the multiplier cannot be ensured to be the same, and the related detection mode is difficult to realize.
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 received signal.
Referring to fig. 1a, fig. 1a 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 invention is used for receiving the reflection light spot of the laser radar, and the laser radar receiving system 10 comprises: a photosensitive receiving front 11, two gate switches 12 and 13, a signal processing circuit 14 and a control circuit 16. The photosensitive receiving array 11 includes at least two rows of photosensitive units, 8 rows in this embodiment, equidistantly distributed: the photosensitive unit 111 and 118. The distance between the centers of two adjacent columns of photosensitive cells is less than or equal to a preset value, so that the reflected light beam projected to the reflected light spot of the photosensitive receiving array surface 11 simultaneously hits at least two photosensitive cells in different columns. As shown in fig. 1a, the photosensitive cells 112 and 113 are simultaneously hit by the reflected light spot. In the present embodiment, the two gating switches 12 and 13 are four-to-one switches, and respectively include four gating paths 121, 122, 123, 124, and 131, 132, 133, 134. 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 the embodiment, two adjacent columns of light sensing units are respectively connected with different gate switches, for example, the light sensing units 112 and 113 are two adjacent columns of light sensing units, the light sensing unit 112 is connected with the gate switch 13, and the light sensing unit 113 is connected with the gate switch 12. For another example, the light sensing units 111 and 112 are two adjacent columns of light sensing units, the light sensing unit 111 is connected to the gate switch 12, and the light sensing unit 112 is connected to the gate switch 13.
The control circuit 16 is connected to the two gate switches 12 and 13, and controls the gate states of the two gate switches 12 and 13. In this embodiment, the control circuit 16 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 pre-calculate the position of the reflected light spot on the photosensitive receiving front 11 according to the parameters, thereby determining at least two rows of photosensitive units to be hit, and control the gating switches 12 and 13 to open corresponding paths according to the at least two rows of photosensitive units. For example, in the scenario shown in fig. 1a, the control circuit 16 calculates in advance that the photosensitive units 112 and 113 will be hit by the reflected light spot, and then controls the path 122 of the gate switch 12 to be opened and the path 131 of the gate switch 13 to be opened, so that the gate switches 12 and 13 can output two paths of signals with correlation to the signal processing circuit 14 for multiplication.
The signal processing circuit 14 is connected to the two gate switches 12 and 13, receives the signals output by the two gate switches 12 and 13, multiplies the two signals to obtain a target signal, and outputs the target signal. As can be seen from the above description, the signal output by the gate switch 12 corresponds to the light pulse received by the light sensing unit 113, the signal output by the gate switch 13 corresponds to the light pulse received by the light sensing unit 112, and the light pulse received by the light sensing unit 113 and the light pulse received by the light sensing unit 112 correspond to the same reflected light spot, so that the signal output by the gate switch 12 and the signal output by the gate switch 13 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 14 includes a multiplier 141, two input terminals of the multiplier 141 are respectively connected to the output terminals of the two gate switches 12 and 13, and the multiplier receives the signals output by the two gate switches 12 and 13 and multiplies the two signals.
In another implementation scenario, when only one of the two gate switches 12 and 13 outputs a signal, and the other does not output a signal or outputs only noise, for example, the path 121 of the gate switch 12 is open and the path 131 of the gate switch 13 is open. If the position of the reflection spot exceeds the photosensitive receiving front 11 and only hits the edge of the photosensitive unit 112, the signal output by the path 131 of the gate switch 13 may only have noise, and the signal corresponding to the reflection spot (the signal output by the path 121 of the gate switch 12) may be smoothed as an interference signal by the multiplication operation of the signal processing circuit 14.
It can be known from the above description that the photosensitive receiving array surface of the laser radar receiving system in this embodiment includes at least two rows of photosensitive units distributed at equal intervals, and the center distance of the photosensitive receiving array surface is adapted to the size of the light spot, so that the reflected light spot of the laser radar simultaneously hits at least two photosensitive units located in different rows, two adjacent rows of photosensitive units are connected to different gating switches, the photosensitive units hit by the reflected light spot are calculated in advance by the control circuit, and the paths corresponding to the gating switches connected to the photosensitive units to be hit are controlled to be opened, so that the gating switches output signals with correlation, and the signals are subjected to multiplication to enhance effective signals, effectively eliminate noise, and thereby improve the signal-to-noise ratio of the output target signals.
Referring to fig. 1b, fig. 1b is a comparison graph of an unamended signal and an output signal of the laser radar receiving system shown in fig. 1a, and it can be seen from fig. 1b 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.
Please continue to refer to fig. 1 a. 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. 1a, 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, a square, and even an irregular figure. The center-to-center pitch of the photosensitive units (e.g., the photosensitive units 112 and the photosensitive units 113) of two adjacent columns is set according to the distance in the horizontal direction of the reflection spot so that the center-to-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 of the 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 units 112 and 113).
As can be seen from the above description, in this embodiment, the center-to-center distance between 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.
Please continue to refer to fig. 1 a. In this embodiment, the lidar receiving system 10 further includes a plurality of amplifiers 151-.
In other implementation scenarios, at least one amplifier may be disposed between the outputs of the gating switches 12 and 13 and the signal processing circuit 14, which also has the effect of enhancing the signal input to the signal processing circuit 14.
In other implementation scenarios, a plurality of amplifiers may be further disposed between the output end of each column in the light sensing units 111 and 118 and the gating switch 12 or 13, so as to enhance the signal output by each column of light sensing units multiple times.
As can be seen from the above description, in this embodiment, an amplifier is connected between the output end of each column of photosensitive cells and the gate switch or between each gate switch and the signal processing circuit, so that the signal strength of the input signal processing circuit can be enhanced, the effective signal is enhanced, and the signal-to-noise ratio of the target signal is improved.
Referring to fig. 1a and fig. 2 in combination, fig. 2 is a schematic structural diagram of an embodiment of a row of light-sensing units in a laser radar receiving system provided in the present invention. As shown in fig. 1a, a column of light-sensing units 111 includes two light-sensing elements 1111, and in other implementation scenarios, a column of light-sensing units 111 may include three, four or even more light-sensing elements 1111. The plurality of light sensing elements 1111 of one column of light sensing units 111 are connected in parallel. In this embodiment, the light sensing element 1111 is an APD (Avalanche Photo Diode), which is a high-sensitivity detector for multiplying a photocurrent by an Avalanche multiplication effect. In other embodiments, other elements having a photoelectric conversion function may be used. When the plurality of parallel connected photosensitive elements 1111 in one row of photosensitive units 111 are hit by the reflected light spot at the same time, the generated signals are superimposed and output.
In the present embodiment, as shown in fig. 1a, the distances between the plurality of photosensitive units 1111 included in each column of photosensitive units 111-118 are equal. That is, if a photosensitive unit includes a plurality of photosensitive elements, the distances between the photosensitive elements are the same, and the distances between the photosensitive elements included in each row of the photosensitive units are the same.
It can be known from the above description that in this embodiment, the APD is adopted as the photosensitive element, and the sensitivity of the laser radar receiving device can be improved, and the photosensitive elements connected in parallel can superpose the signal generated after being hit, so as to further enhance the strength of the effective signal, and thus the signal-to-noise ratio of the target signal is more effectively improved.
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 provided by the invention is used for receiving the reflection light spot of the laser radar, and the laser radar receiving system 20 comprises: a photosensitive receiving array 21, four gate switches 22, 23, 24 and 25, a signal processing circuit 26 and an amplifier 2701-.
The photosensitive receiving wavefront 21 comprises 16 rows of photosensitive units 2101 and 2116 which are distributed at equal intervals, the distance between the centers of two adjacent rows of photosensitive units is less than or equal to the preset value, the reflected light spots of the laser radar can simultaneously hit 4 rows of photosensitive units, as shown in fig. 3, and the photosensitive units 2101 and 2104 are simultaneously hit by the reflected light spots. The four gating switches 22, 23, 24 and 25 are all four-to-one switches, and respectively include four gating paths, the gating switch 22 includes paths 221, 222, 223 and 224, the gating switch 23 includes paths 231, 232, 233 and 234, the gating switch 24 includes paths 241, 242, 243 and 244, and the gating switch 25 includes paths 251, 252, 253 and 254. 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. The adjacent 4 columns of photosensitive units are respectively connected with different gating switches. For example, the light sensing unit 2101 is connected to the gate switch 22, the light sensing unit 2102 is connected to the gate switch 23, the light sensing unit 2103 is connected to the gate switch 24, and the light sensing unit 2104 is connected to the gate switch 25.
The signal processing circuit 26 includes two first- stage multipliers 261 and 262, and a second-stage multiplier 263. Two input terminals of the first-stage multiplier 261 are connected to the output terminals of the two adjacent gating switches 22 and 23, respectively, and two input terminals of the first-stage multiplier 262 are connected to the two adjacent gating switches 24 and 25, respectively. Only one first-stage multiplier (multiplier 261 or 262) is connected to any one of the gate switches 22-25. Two inputs of the two-stage multiplier 263 are connected to outputs of the one- stage multipliers 261 and 262. The amplifiers 2701-2716 are respectively connected between each column of photosensitive units (2101-2116) and the gating switches 22-25.
In the present implementation scenario, the reflected light spot hits the photosensitive cells 2101, 2102, 2103, and 2104 on the photosensitive receiving front 21, the path 221 of the gating switch 22 is opened, the path 231 of the gating switch 23 is opened, the path 241 of the gating switch 24 is opened, and the path 251 of the gating switch 25 is opened. The signal generated by the photo-sensing unit 2101 hit by the reflected light spot is amplified by the amplifier 2701 and transmitted to one input of the first-stage multiplier 261 via the path 221 of the gating switch 22. The signal generated by the photosensitive unit 2102 after being hit by the reflected light spot is amplified by the amplifier 2702, and then transmitted to the other input terminal of the first-stage multiplier 261 through the path 231 of the gating switch 23. The first-stage multiplier 261 performs multiplication operation on the two signals to obtain a primary processing signal. Similarly, the signal generated after the light sensing unit 2103 is hit by the reflected light spot is amplified by the amplifier 2703, and then transmitted to one input terminal of the primary multiplier 262 through the path 241 of the gating switch 24. The signal generated by the light sensing unit 2104 hit by the reflected light spot is amplified by the amplifier 2704 and then transmitted to the other input terminal of the first-stage multiplier 262 through the path 251 of the gating switch 25. The first-stage multiplier 262 multiplies the two signals to obtain a primary processing signal. The first- stage multipliers 261 and 262 transmit the respective preliminary processing signals to the second-stage multiplier 263, and the second-stage multiplier 263 performs multiplication operations on the two signals to obtain target signals.
The light-sensing units 2101, 2102, 2103 and 2104 are hit by the same reflected light spot, so that the signals output by the light-sensing units 2101, 2102, 2103 and 2104 have correlation. Similar to the first embodiment of the lidar receiving system provided by the present invention, after the signals of the photosensitive units 2101 and 2102 are processed by the first-stage multiplier 261, the effective signal with correlation is enhanced, and the noise without correlation is smoothed or reduced. Similarly, after the signals of the light sensing units 2103 and 2104 are processed by the first-stage multiplier 262, the effective signal with correlation is enhanced, and the noise without correlation is smoothed or reduced. The second-stage multiplier 263 multiplies the primary processed signals output by the first- stage multipliers 261 and 262, so that the effective signals in the primary processed signals output by the first- stage multipliers 261 and 262 are further enhanced, the noise is further smoothed or reduced, and the output target signals have higher signal-to-noise ratio.
As can be seen from the above description, in this embodiment, by adjusting the distance between the photosensitive units in each column, the reflected light spot can simultaneously hit more photosensitive units in different columns, and correspondingly more gating switches are provided, and signals output by the gating switches are subjected to multi-stage multiplication, so that the effective signal can be further enhanced, the noise is further smoothed or reduced, and the output target signal has a higher signal-to-noise ratio.
Referring to fig. 4, fig. 4 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 30 provided by the present invention is used for receiving the reflection light spot of the laser radar, and the laser radar receiving system 30 includes: a photosensitive receiving front 31, three gate switches 32, 33 and 34, a signal processing circuit 35, and an amplifier 361-.
The photosensitive receiving array surface 31 includes 9 rows of photosensitive units 311-319 which are distributed at equal intervals, the central distance between two adjacent rows of photosensitive units is smaller than or equal to the preset value, the reflection light spot of the laser radar can simultaneously hit 3 rows of photosensitive units, as shown in fig. 4, the photosensitive units 311-313 are simultaneously hit by the reflection light spot. The three gating switches 32, 33 and 34 are all one-out-of-three switches, and respectively comprise three gating paths, the gating switch 32 comprises paths 321, 322 and 323, the gating switch 33 comprises paths 331, 332 and 333, and the gating switch 34 comprises paths 341, 342 and 343. 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. And the adjacent 3 columns of photosensitive units are respectively connected with different gating switches. For example, the light sensing unit 311 is connected to the gate switch 32, the light sensing unit 312 is connected to the gate switch 33, and the light sensing unit 313 is connected to the gate switch 34. The amplifiers 361 and 369 are respectively connected between each of the columns of photo-sensing units 311 and 319 and the gate switches 32-34. The signal processing circuit 35 includes a first-stage multiplier 351 and a second-stage multiplier 352. Two input terminals of the first-stage multiplier 351 are respectively connected to the output terminals of two adjacent gate switches 32 and 33, one input terminal of the second-stage multiplier 352 is connected to the output terminal of the first-stage multiplier 351, and the other input terminal is connected to the output terminal of the gate switch 34.
In the present implementation scenario, the reflected light spot hits the photosensitive cells 311, 312, and 314 on the photosensitive receiving front 31, the path 321 of the gate switch 32 is opened, the path 331 of the gate switch 33 is opened, and the path 341 of the gate switch 34 is opened. The signal generated by the photosensitive unit 311 after being hit by the reflected light spot is amplified by the amplifier 361 and transmitted to one input terminal of the first-stage multiplier 351 through the path 321 of the gating switch 32. The signal generated by the photosensitive unit 312 after being hit by the reflected light spot is amplified by the amplifier 362 and transmitted to the other input terminal of the one-stage multiplier 351 through the path 331 of the gating switch 33. The first-stage multiplier 351 performs multiplication operation on the two signals to obtain a primary processing signal. The signal generated by the light sensing unit 313 after being hit by the reflected light spot is amplified by the amplifier 363 and transmitted to one input terminal of the second-stage multiplier 352 through the path 341 of the gating switch 34. The output terminal of the first-stage multiplier 351 is connected to the other input terminal of the second-stage multiplier 352.
The light sensing units 311, 312 and 313 are hit by the same reflected light spot, so the signals output by the light sensing units 311, 312 and 313 all have correlation. Similar to the first embodiment of the lidar receiving system provided by the present invention, after the signals output by the light sensing units 311 and 312 are processed by the first-stage multiplier 351, the effective signals with correlation are enhanced, and the noise without correlation is smoothed or reduced. The primary processed signal output by the primary multiplier 351 has the same correlation with the signal output by the photosensitive unit 313. The two-stage multiplier 352 multiplies the primary processing signal output by the one-stage multiplier 351 and the signal output by the photosensitive unit 313, so that the effective signal can be further enhanced, the noise can be further smoothed or weakened, and the output target signal has a higher signal-to-noise ratio.
In the implementation scenario, the gating switch opens only one path at the same time to receive the signals of the photosensitive units, and the central distance of each row of photosensitive units can be adjusted according to the precision requirement of the 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 all hit by the reflected light spots at the same time is avoided.
In other embodiments, the multiplier may have more and/or more stages, which may further enhance the effective signal and eliminate noise. For example, when the laser radar receiving system has a plurality of gating switches, the signal processing circuit includes multiple stages of multipliers, the output end of each gating switch is connected to one input end of a corresponding multiplier, and the output ends of any two multipliers are connected to the input end of a next-stage multiplier, so as to multiply the output result of the previous-stage multiplier twice until only one output of the next-stage multiplier is obtained.
As can be seen from the above description, in this embodiment, the signal processing circuit includes a multi-stage multiplier to perform multi-stage multiplication on the signals output by the plurality of gate switches, so as to further enhance the effective signal, eliminate noise, and improve the signal-to-noise ratio of the target signal.
Referring to fig. 5, fig. 5 is a schematic structural diagram of a laser radar according to an embodiment of the present invention. The lidar 40 provided by the present invention comprises a laser emitting module 41 and a lidar receiving system 42, wherein the lidar receiving system 42 comprises the lidar receiving system shown in fig. 1a, fig. 3 or fig. 4.
As shown in fig. 5, the laser emitting module 41 is used for generating a laser beam and then scanning the laser beam to a target scanning area, where an object in the target scanning area reflects the laser beam to obtain a reflected beam, and 51 and 52 are reflected spots where the reflected beam is projected to the laser radar receiving system 42. As can be seen from the above description, the lidar receiving system 42 includes a photosensitive receiving array, which includes at least two rows of photosensitive units, the distance between the centers of two adjacent rows of photosensitive units is smaller than or equal to a preset value, and the size of the reflection spots (e.g., the reflection spots 51 and 52) of the laser beam emitted by the laser emitting module 41 is adapted to the preset value, so that the reflection spot 51 or the reflection spot 52 can simultaneously hit at least two photosensitive units located in different rows.
The laser radar receiving system 42 further includes at least two gating switches and a control circuit, and two adjacent columns of light-sensing units are respectively connected to different gating switches. The control circuit is connected with the at least two gate switches and the laser emission module 41, can obtain the predicted position of the reflected light spot (for example, 51 or 52), and controls the gate state of the gate switch according to the predicted position, and only one channel of the selected gate switch is opened.
The lidar receiving system 42 further includes a signal processing circuit, which is connected to the at least two gate switches, and multiplies the signals output by the at least two gate switches to obtain a target signal and outputs the target signal.
Because the signals output by the at least two gating switches are generated after at least two columns of adjacent photosensitive units are hit by the same reflection light spot (such as the reflection light spot 51 or 52), the signals output by the at least two gating switches have correlation, the time delay difference of the at least two signals is small, the at least two signals are subjected to multiplication processing, so that the effective signals with the correlation can be enhanced, the noise without the correlation can be eliminated, and the effective signals which are originally submerged by the noise can be retained and enhanced.
Further, in order to improve the receiving effect of the laser radar receiving system 42, the laser radar 40 further includes a receiving lens 43, and the receiving lens 43 is configured to receive the reflected light beam, so that the reflected light beam can irradiate onto a photosensitive receiving front of the laser radar receiving system 42.
It can be known from the above description that the photosensitive receiving array surface of the laser radar receiving system of the laser radar in this embodiment includes at least two rows of photosensitive units distributed at equal intervals, and the center distance of the photosensitive receiving array surface is adapted to the size of the light spot, so that the reflected light spot of the laser radar simultaneously hits at least two photosensitive units located in different rows, two adjacent rows of photosensitive units are connected to different gating switches, the photosensitive units to be hit by the reflected light spot are calculated in advance by the control circuit, and the channels of the gating switches connected to the photosensitive units to be hit are controlled to be opened, so that the signals with correlation are output by the gating switches, effective signals can be enhanced by performing multiplication on the signals, noise is effectively eliminated, and the signal-to-noise ratio of the output target signals is improved.
Different from the prior art, the method provided by the invention has the advantages that the center distance between at least two rows of photosensitive units of the photosensitive receiving array surface is adjusted, so that the reflected light spots of the laser radar simultaneously hit at least two photosensitive units in different rows, and the adjacent two rows of photosensitive units are connected with different gating switches, so that signals output by the gating switches correspond to the same reflected light spot, and thus, the correlation is realized, the multiplication operation is performed on at least two paths of signals with correlation, the noise can be effectively eliminated, the effective signals are enhanced, and the signal-to-noise ratio of the output target 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 (10)
1. A lidar receiving system configured to receive a reflected beam of a lidar; the system comprises:
the photosensitive receiving array surface comprises at least two rows of photosensitive units which are distributed at equal intervals, and the center distance between every two adjacent rows of photosensitive units is smaller than or equal to a preset value, so that the reflected light beams projected to the reflective light spots of the photosensitive receiving array surface simultaneously hit at least two photosensitive units in different rows;
the two adjacent columns of the light sensing units are respectively connected with different gating switches;
the control circuit is connected with the at least two gating switches and used 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;
and the signal processing circuit is connected with the at least two gating switches, performs multiplication processing on signals output by the at least two gating switches to obtain a target signal, and outputs the target signal.
2. 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 spots in a horizontal direction.
3. The lidar receiving system of claim 1, wherein the light sensing unit of each column comprises a plurality of light sensing elements, the plurality of light sensing elements of each column being connected in parallel.
4. The lidar receiving system according to claim 1, wherein the signal processing circuit comprises at least one primary multiplier, two input terminals of each primary multiplier are respectively connected to output terminals of the gating switches corresponding to two adjacent columns of the photosensitive units, and the gating switch corresponding to each column of the photosensitive units is connected to only one of the primary multipliers.
5. The lidar reception system of claim 4, wherein the signal processing circuit further comprises at least one secondary multiplier, at least one input of the at least one secondary multiplier being coupled to an output of the at least one primary multiplier.
6. The lidar reception system of claim 1, wherein the signal processing circuit comprises a multi-stage multiplier; the output end of each gating switch is connected to one input end of the corresponding multiplier; the output ends of any two multipliers are connected with the input end of a next multiplier so as to multiply the output result of the previous multiplier for the second time until only one output of the next multiplier is obtained.
7. The lidar receiving system of claim 1, wherein the number of gating switches is greater than or equal to the number of columns of light sensing units simultaneously hit by the reflection spots.
8. The lidar receiving system of claim 1, further comprising amplifiers, each of the amplifiers being connected between an output of a column of light sensing units and a gating switch connected thereto for amplifying an output signal of the light sensing unit; or
Each of the amplifiers is disposed between an output terminal of each of the gate switches and the signal processing circuit.
9. A lidar, comprising:
the laser emission module is used for generating a laser beam and then scanning a target scanning area, 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 laser emitting module is adapted to the predetermined value.
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| CN111352095B (en) * | 2020-04-17 | 2024-12-31 | 深圳市镭神智能系统有限公司 | Laser radar receiving system and laser radar |
| CN111352096B (en) * | 2020-04-26 | 2022-08-09 | 深圳市镭神智能系统有限公司 | Laser radar receiving system and laser radar |
| CN113866781A (en) * | 2020-06-30 | 2021-12-31 | 华为技术有限公司 | Laser radar system and detection method |
| CN114063043A (en) * | 2020-07-30 | 2022-02-18 | 北京一径科技有限公司 | Control method and device of photoelectric detection array, photoelectric power supply switching circuit and photoelectric detection array |
| JP2022103109A (en) * | 2020-12-25 | 2022-07-07 | 株式会社リコー | Object detection device, sensing device and moving object |
| CN115508811B (en) * | 2021-06-22 | 2025-09-19 | 上海禾赛科技有限公司 | Optical detection circuit, optical detection method, laser radar, and storage medium |
| KR20240021894A (en) * | 2021-06-22 | 2024-02-19 | 헤사이 테크놀로지 씨오., 엘티디. | Light detection circuit and method, laser radar, storage medium, detection system |
| CN119439296A (en) * | 2024-09-26 | 2025-02-14 | 中国科学院西安光学精密机械研究所 | A device and method for detecting weak near-infrared signals in gravitational wave detection |
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