CN110275173B - Laser ranging system - Google Patents
Laser ranging system Download PDFInfo
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- CN110275173B CN110275173B CN201810206211.9A CN201810206211A CN110275173B CN 110275173 B CN110275173 B CN 110275173B CN 201810206211 A CN201810206211 A CN 201810206211A CN 110275173 B CN110275173 B CN 110275173B
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Classifications
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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
- G01S17/06—Systems determining position data of a target
- G01S17/08—Systems determining position data of a target for measuring distance only
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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
- G01S7/4814—Constructional features, e.g. arrangements of optical elements of transmitters alone
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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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- Physics & Mathematics (AREA)
- Computer Networks & Wireless Communication (AREA)
- General Physics & Mathematics (AREA)
- Radar, Positioning & Navigation (AREA)
- Remote Sensing (AREA)
- Electromagnetism (AREA)
- Optical Radar Systems And Details Thereof (AREA)
Abstract
The invention is suitable for the laser ranging field, and discloses a laser ranging system, which comprises: the system comprises a logic control module, a signal conversion module, an optical module, a laser emission module and an echo detection module; the logic control module sends a control signal to the laser emission module; the laser emission module generates a driving signal according to the control signal, sends the driving signal as a reference signal to the signal conversion module, and emits pulse laser; the pulse laser is emitted to the target object through the optical module and generates laser echo; the laser echo is emitted to the echo detection module through the optical module; the echo detection module converts the laser echo into an echo electric signal and sends the echo electric signal to the signal conversion module; the signal conversion module respectively carries out analog-to-digital conversion on the echo electric signal and the reference signal and sends the echo electric signal and the reference signal to the logic control module; the logic control module obtains the distance measurement distance according to the converted reference signal and the converted echo electric signal. The invention can eliminate delay errors and improve the accuracy of laser ranging.
Description
Technical Field
The invention belongs to the technical field of laser ranging, and particularly relates to a laser ranging system.
Background
The laser ranging is to take a laser as a light source, emit pulse laser, after the pulse laser is emitted to a target object, a part of the laser is reflected to a ranging point, and the distance between the ranging point and the measured target object can be calculated by measuring the round-trip time of the laser.
The existing laser ranging system uses an original control signal as a reference signal, however, the laser ranging system can bring delay errors, so that the ranging result is inaccurate.
Disclosure of Invention
In view of the above, the embodiment of the invention provides a laser ranging system to solve the problem that the existing laser ranging system has delay errors, so that the ranging result is inaccurate.
The embodiment of the invention provides a laser ranging system, which comprises: the system comprises a logic control module, a signal conversion module, an optical module, a laser emission module and an echo detection module;
the logic control module is connected with the laser emission module, the laser emission module and the echo detection module are respectively connected with the signal conversion module, and the signal conversion module is connected with the logic control module;
the logic control module sends a control signal to the laser emission module; the laser emission module generates a driving signal according to the control signal, takes the driving signal as a reference signal, sends the reference signal to the signal conversion module, and emits pulse laser according to the control signal; the pulse laser is emitted to the target object through the optical module, and a laser echo is generated; the laser echo is emitted to the echo detection module through the optical module; the echo detection module converts laser echo into an echo electric signal and sends the echo electric signal to the signal conversion module; the signal conversion module carries out analog-to-digital conversion on the echo electric signal to obtain a converted echo electric signal, carries out analog-to-digital conversion on the reference signal to obtain a converted reference signal, and sends the converted reference signal and the converted echo electric signal to the logic control module; the logic control module obtains the distance measurement distance according to the converted reference signal and the converted echo electric signal.
Optionally, the laser emitting module includes a preset number of laser emitting units, and the laser emitting units include a laser diode and a laser driving circuit;
the logic control module is connected with the laser driving circuit, and the laser driving circuit is respectively connected with the laser diode and the signal conversion module;
the logic control module sends a control signal to the laser driving circuit, the laser driving circuit generates a driving signal according to the control signal, the driving signal is used as a reference signal, the reference signal is sent to the laser diode and the signal conversion module, and the reference signal drives the laser diode to emit pulse laser.
Optionally, the echo detection module comprises a preset number of echo detection units, the echo detection units comprise photoelectric sensors and signal processing circuits, and the echo detection units are in one-to-one correspondence with the laser emission units;
the photoelectric sensor is connected with the signal processing circuit, and the signal processing circuit is connected with the signal conversion module;
the laser echo is emitted to the photoelectric sensor through the optical module; the photoelectric sensor converts the laser echo into an echo electric signal and sends the echo electric signal to the signal processing circuit; the signal processing circuit carries out filtering denoising and signal amplification processing on the echo electric signal to obtain a processed echo electric signal, and sends the processed echo electric signal to the signal conversion module; the signal conversion module carries out analog-to-digital conversion on the processed echo electric signal to obtain a converted echo electric signal;
the logic control module performs digital filtering on the converted echo electric signals to obtain filtered echo electric signals, performs threshold segmentation on the filtered echo electric signals to obtain segmented echo electric signals, and obtains the centroid of the segmented echo electric signals to obtain a first centroid; the logic control module performs digital filtering on the converted reference signal to obtain a filtered reference signal, performs threshold segmentation on the filtered reference signal to obtain a segmented reference signal, and obtains the centroid of the segmented reference signal to obtain a second centroid; the logic control module calculates the sampling time difference of the first centroid and the second centroid, and obtains the distance measurement distance according to the sampling time difference.
Optionally, the logic control module calculates the peak area of the divided echo electric signal, takes the peak area as laser echo energy, obtains a laser emission power adjusting signal according to the laser echo energy and the distance measurement distance, sends the laser emission power adjusting signal to the laser emission module, and adjusts the laser emission power according to the laser emission power adjusting signal.
Optionally, the signal processing circuit includes a filtering denoising circuit and a signal amplifying circuit;
the photoelectric sensor is connected with the filtering denoising circuit, the filtering denoising circuit is connected with the signal amplifying circuit, and the signal amplifying circuit is connected with the signal conversion module;
the photoelectric sensor sends the echo electric signal to a filtering denoising circuit; the filtering denoising circuit performs filtering denoising processing on the echo electric signal to obtain a filtered denoised echo electric signal, and sends the filtered denoised echo electric signal to the signal amplifying circuit, and the signal amplifying circuit performs signal amplifying processing on the filtered denoised echo electric signal to obtain a processed echo electric signal and sends the processed echo electric signal to the signal conversion module.
Optionally, the optical module includes a transmitting lens and a receiving lens;
the transmitting lens converges the pulse laser, performs collimation adjustment on the pulse laser to obtain adjusted pulse laser, and transmits the adjusted pulse laser to a target object; the receiving lens carries out collimation adjustment on the laser echo to obtain an adjusted laser echo, and the adjusted laser echo is converged to the echo detection module.
Optionally, the optical module further comprises an optical housing;
the optical outer cover performs stray light filtering treatment on the adjusted pulse laser, filters stray light outside the pulse laser wave band, and transmits the pulse laser with the stray light filtered to a target object; the optical housing filters the stray light from the laser echo, filters the stray light outside the pulse laser band, and transmits the laser echo with the stray light filtered to the receiving lens.
Optionally, the optical housing comprises an optical film.
Optionally, the signal conversion module includes a dual-channel analog-to-digital conversion unit;
one channel of the two-channel analog-to-digital conversion unit carries out analog-to-digital conversion on the echo electric signal to obtain a converted echo electric signal, and the other channel carries out analog-to-digital conversion on the reference signal to obtain a converted reference signal.
Optionally, the logic control module comprises a field programmable gate array.
Compared with the prior art, the embodiment of the invention has the beneficial effects that: the laser ranging system in the embodiment of the invention comprises: the system comprises a logic control module, a signal conversion module, an optical module, a laser emission module and an echo detection module; the logic control module is connected with the laser emission module, the laser emission module and the echo detection module are respectively connected with the signal conversion module, and the signal conversion module is connected with the logic control module; the logic control module sends a control signal to the laser emission module; the laser emission module generates a driving signal according to the control signal, takes the driving signal as a reference signal, sends the reference signal to the signal conversion module, carries out analog-to-digital conversion on the echo electric signal to obtain a converted echo electric signal, carries out analog-to-digital conversion on the reference signal to obtain a converted reference signal, and sends the converted reference signal and the converted echo electric signal to the logic control module; the logic control module obtains the distance measurement distance according to the converted reference signal and the converted echo electric signal. The embodiment of the invention can solve the problem that the existing laser ranging system has delay errors, thereby causing inaccurate ranging results, eliminating the delay errors and improving the accuracy of laser ranging.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the embodiments or the description of the prior art will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic block diagram of a laser ranging system provided in an embodiment of the present invention;
FIG. 2 is a schematic block diagram of a laser ranging system provided in another embodiment of the present invention;
FIG. 3 is a schematic waveform diagram of an embodiment of the present invention;
FIG. 4 is a schematic diagram of a converted echo electrical signal provided by an embodiment of the present invention;
FIG. 5 is a schematic diagram of a filtered echo electrical signal provided by an embodiment of the present invention;
FIG. 6 is a schematic diagram of a segmented echo electrical signal provided by an embodiment of the present invention;
FIG. 7 is a schematic diagram of extracting centroid according to an embodiment of the present invention;
FIG. 8 is a schematic diagram of a laser ranging system according to an embodiment of the present invention;
FIG. 9 is a schematic diagram of the laser emitting module 14 of FIG. 8 according to an embodiment of the present invention;
fig. 10 is a schematic structural view of the laser emitting unit 141 in fig. 9 according to an embodiment of the present invention;
FIG. 11 is a schematic diagram illustrating the structure of the echo detection module 15 in FIG. 8 according to an embodiment of the present invention;
fig. 12 is a schematic structural diagram of the echo detecting unit 151 in fig. 11 according to an embodiment of the present invention;
FIG. 13 is a schematic diagram of a laser ranging system according to another embodiment of the present invention;
fig. 14 is a top view of a laser ranging system according to an embodiment of the present invention.
Detailed Description
In the following description, for purposes of explanation and not limitation, specific details are set forth, such as particular system configurations, techniques, etc. in order to provide a thorough understanding of the embodiments of the present application. It will be apparent, however, to one skilled in the art that the present application may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present application with unnecessary detail.
It should be understood that the terms "comprises" and/or "comprising," when used in this specification and the appended claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
It is also to be understood that the terminology used in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in this specification and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.
It should be further understood that the term "and/or" as used in this specification and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes such combinations.
As used in this specification and the appended claims, the term "if" may be interpreted as "when..once" or "in response to a determination" or "in response to detection" depending on the context. Similarly, the phrase "if a determination" or "if a [ described condition or event ] is detected" may be interpreted in the context of meaning "upon determination" or "in response to determination" or "upon detection of a [ described condition or event ]" or "in response to detection of a [ described condition or event ]".
In order to illustrate the technical scheme of the invention, the following description is made by specific examples.
Fig. 1 is a schematic block diagram of a laser ranging system according to an embodiment of the present invention, and only a portion related to the embodiment of the present invention is shown for convenience of explanation. As shown in fig. 1, the laser ranging system 1 may include: a logic control module 11, a signal conversion module 12, an optical module 13, a laser emission module 14 and an echo detection module 15;
the logic control module 11 is connected with the laser emission module 14, the laser emission module 14 and the echo detection module 15 are respectively connected with the signal conversion module 12, and the signal conversion module 12 is connected with the logic control module 11;
the logic control module 11 sends a control signal to the laser emission module 14; the laser emission module 14 generates a driving signal according to the control signal, takes the driving signal as a reference signal, and sends the reference signal to the signal conversion module 12, and the laser emission module 14 emits pulse laser according to the control signal; the pulse laser is emitted to the target object through the optical module 13 and generates laser echo; the laser echo is emitted to the echo detection module 15 through the optical module 13; the echo detection module 15 converts the laser echo into an echo electric signal and sends the echo electric signal to the signal conversion module 12; the signal conversion module 12 performs analog-to-digital conversion on the echo electric signal to obtain a converted echo electric signal, the signal conversion module 12 performs analog-to-digital conversion on the reference signal to obtain a converted reference signal, and the converted reference signal and the converted echo electric signal are sent to the logic control module 11; the logic control module 11 obtains a ranging distance according to the converted reference signal and the converted echo electric signal.
In the embodiment of the present invention, the logic control module 11 is a driving core of the laser ranging system 1, the logic control module 11 sends a control signal to the laser emitting module 14, the control signal is a high-frequency pulse signal, the control signal drives the laser emitting module 14 to emit pulse laser, meanwhile, the laser emitting module 14 generates a driving signal according to the control signal, the driving signal is used as a reference signal, and the reference signal is sent to the signal conversion module 12. The pulse laser is converged into a laser beam by the optical module 13, and emitted to the target object, and when the laser beam is blocked by the target object, a laser echo is generated. The laser echoes are converged to the echo detection module 15 through the optical module 13, and the echo detection module 15 converts the laser echoes into echo electric signals and sends the echo electric signals to the signal conversion module 12. The signal conversion module 12 performs analog-to-digital conversion on the reference signal and the echo electric signal, respectively, and transmits the converted reference signal and the converted echo electric signal to the logic control module 11. The logic control module 11 obtains the ranging distance by analyzing the converted reference signal and the converted echo electric signal.
The existing laser ranging system uses a control signal as a reference signal, but because the control signal needs to be sent to a laser emitting device (the laser emitting device is any device capable of emitting laser) through a laser driving circuit, and electronic elements in the laser driving circuit have response time, and the response time of the electronic elements is different under different temperature and humidity conditions, the laser ranging system using the control signal as the reference signal has delay errors, so that the ranging result is inaccurate. The embodiment of the invention sends the control signal to the laser emitting module through the logic control module, the signal conversion module, the optical module, the laser emitting module, the echo detection module and the connection relation among the logic control module, the signal conversion module, the optical module, the laser emitting module and the echo detection module; the laser emission module generates a driving signal according to the control signal, takes the driving signal as a reference signal and sends the reference signal to the signal conversion module; the signal conversion module carries out analog-to-digital conversion on the echo electric signal to obtain a converted echo electric signal, carries out analog-to-digital conversion on the reference signal to obtain a converted reference signal, and sends the converted reference signal and the converted echo electric signal to the logic control module; the logic control module obtains the ranging distance according to the converted reference signal and the converted echo electric signal, so that the problem of inaccurate ranging result caused by delay errors of the existing laser ranging system can be solved, the delay errors can be eliminated, and the accuracy of laser ranging is improved; in the embodiment of the invention, pulse laser is emitted to a target object through an optical module and laser echo is generated; the laser echo is emitted to the echo detection module through the optical module, the optical path design is simple, and no additional optical equipment is needed.
Fig. 2 is a schematic block diagram of a laser ranging system provided in accordance with yet another embodiment of the present invention. It should be noted that, in fig. 2, only one laser emitting unit and only one echo detecting unit are shown, but in practical application, the number of the laser emitting units and the number of the echo detecting units may be set according to practical requirements, and the laser emitting units and the echo detecting units are in one-to-one correspondence.
As still another embodiment of the present invention, as shown in fig. 2, the laser emitting module 14 includes a preset number of laser emitting units 141, and the laser emitting units 141 include a laser diode 1411 and a laser driving circuit 1412;
the logic control module 11 is connected with the laser driving circuit 1412, and the laser driving circuit 1412 is respectively connected with the laser diode 1411 and the signal conversion module 12;
the logic control module 11 sends a control signal to the laser driving circuit 1412, the laser driving circuit 1412 generates a driving signal according to the control signal, takes the driving signal as a reference signal, and sends the reference signal to the laser diode 1411 and the signal conversion module 12, and the reference signal drives the laser diode 1411 to emit pulsed laser light.
In the embodiment of the present invention, the laser emitting module 14 is a laser emitting array composed of a preset number of laser emitting units 141, where the preset number can be set according to actual requirements. Each of the laser emitting units includes a laser diode 1411 and a laser driving circuit 1412. The laser driving circuit 1412 generates a driving signal based on the control signal transmitted from the logic control module 11, and transmits the driving signal as a reference signal to the signal conversion module 12 and the laser diode 1411, and the driving signal drives the laser diode 1411 to emit pulse laser light, and at most one laser diode emits pulse laser light at the same time. The embodiment of the invention can eliminate delay errors generated by the laser driving circuit and improve the accuracy of laser ranging.
As still another embodiment of the present invention, the echo detection module 15 includes a preset number of echo detection units 151, the echo detection units 151 include a photosensor 1511 and a signal processing circuit 1512, and the echo detection units 151 are in one-to-one correspondence with the laser emission units 141;
the photosensor 1511 is connected to the signal processing circuit 1512, and the signal processing circuit 1512 is connected to the signal conversion module 12;
the laser echo is emitted to the photosensor 1511 through the optical module 13; the photosensor 1511 converts the laser echo into an echo electric signal, and sends the echo electric signal to the signal processing circuit 1512; the signal processing circuit 1512 performs filtering denoising and signal amplification processing on the echo electric signal to obtain a processed echo electric signal, and sends the processed echo electric signal to the signal conversion module 12; the signal conversion module 12 performs analog-to-digital conversion on the processed echo electric signal to obtain a converted echo electric signal;
the logic control module 11 performs digital filtering on the converted echo electric signal to obtain a filtered echo electric signal, performs threshold segmentation on the filtered echo electric signal to obtain a segmented echo electric signal, and obtains the centroid of the segmented echo electric signal to obtain a first centroid; the logic control module 11 performs digital filtering on the converted reference signal to obtain a filtered reference signal, performs threshold segmentation on the filtered reference signal to obtain a segmented reference signal, and obtains the centroid of the segmented reference signal to obtain a second centroid; the logic control module 11 calculates a sampling time difference between the first centroid and the second centroid, and obtains a ranging distance according to the sampling time difference.
In the embodiment of the present invention, the echo detection module 15 is an echo detection array composed of a preset number of echo detection units 151, the number of the echo detection units 151 is the same as that of the laser emission units 141, and the echo detection units 151 are in one-to-one correspondence with the laser emission units 141. Each echo detection unit 151 includes a photosensor 1511 and a signal processing circuit 1512. The photoelectric sensor 1511 can detect a laser echo and convert the laser echo into an echo electric signal; the signal processing circuit 1512 performs filtering denoising and signal amplification processing on the echo electric signal.
The logic control module 11 analyzes the converted echo electric signal and the converted reference signal, and calculates a sampling time difference by adopting a digital signal processing technology. Digital signal processing techniques include digital filtering, threshold segmentation, centroid extraction, and time of day discrimination.
The digital filtering means that a high-order filter is adopted to carry out frequency domain filtering on the converted echo electric signal and the converted reference signal, high-frequency clutter and low-frequency clutter in the converted echo electric signal and the converted reference signal are filtered, smoother signals are output, and meanwhile peak value information and phase information of the signals are reserved. Wherein the order of the high order filter is not lower than 30.
The threshold segmentation means that peak data in the signal are segmented, a large amount of invalid data is removed in the process, only the peak data is reserved, and the operation amount of a subsequent algorithm can be greatly reduced. For the converted echo electric signals, a dynamic threshold method is adopted for threshold segmentation, the threshold of each frame of data is required to be updated through a dynamic threshold algorithm, and in order to ensure the integrity of the signals, edge supplementation is carried out on the segmented signals, and the width of the edge supplementation is an empirical value. For the converted reference signal, the peak data and other data have obvious differences, so that the static threshold value is adopted for segmentation, and the size of the static threshold value is an empirical value. As shown in fig. 3, the divided reference signal is 31, and the divided echo electric signal is 32.
Centroid extraction refers to extracting centroid positions of the segmented echo electric signals and the segmented reference signals. The centroid of the segmented echo electrical signal, shown as 34 in fig. 3, and the centroid of the segmented reference signal, shown as 33 in fig. 3, are extracted by weighted averaging the heights of the signals, respectively.
The time discrimination refers to obtaining the sampling time difference between the first centroid and the second centroid, that is, the sampling time difference between the first centroid and the second centroid is obtained by subtracting T1 from T2 in fig. 3, and the sampling time difference is the flight time of the pulse laser. The logic control module 11 calculates the distance measurement according to the sampling time difference, and the specific calculation formula is as follows:where d is the distance measurement, T is the sampling time difference, and c is the propagation speed of the light.
Illustratively, fig. 4 is a converted echo electrical signal, fig. 5 is a filtered echo electrical signal, fig. 6 is a segmented echo electrical signal, and fig. 7 is a centroid of an extracted segmented echo electrical signal 71.
In the embodiment of the invention, most Gaussian noise can be filtered through digital filtering; the time resolution can be improved through threshold segmentation, a large amount of invalid data is removed, and the operand of a subsequent algorithm is greatly reduced; by extracting the barycenters and solving the sampling time difference of the two barycenters, drift errors caused by signal distortion can be effectively overcome, and the accuracy of laser ranging is improved; after the signals are subjected to digital filtering, threshold segmentation and centroid extraction, the accuracy of time discrimination can reach 50 picoseconds.
As still another embodiment of the present invention, the logic control module 11 calculates the peak area of the divided echo electric signal, uses the peak area as the laser echo energy, obtains a laser emission power adjustment signal according to the laser echo energy and the ranging distance, sends the laser emission power adjustment signal to the laser emission module 14, and the laser emission module 14 adjusts the laser emission power according to the laser emission power adjustment signal.
The peak area of the divided echo electric signal may be the area of a closed pattern formed by the divided echo signal and a horizontal axis, or the area of a closed pattern formed by the divided echo electric signal and a preset echo reference line.
The logic control module 11 calculates a control variable according to the laser echo energy and the distance measurement distance, carries out quantization processing on the control variable, inquires a preset control rule according to the quantization level, and obtains a laser emission power adjustment signal according to the control rule. The logic control module 11 sends a laser emission power adjustment signal to the laser emission module 14, and the laser emission module 14 adjusts the laser emission power according to the laser emission power adjustment signal.
According to the embodiment of the invention, the light intensity attenuation caused by environmental factors such as atmospheric scattering and the like can be estimated according to the laser echo energy and the ranging distance, and the laser emission module is controlled to adjust the laser emission power.
As still another embodiment of the present invention, the echo detection unit 151 further includes a light guide 1513; the light guide 1513 is connected with the photosensor 1511; the laser echo is emitted to the light guide 1513 through the optical module 13, and the light guide 1513 guides the laser echo to the photosensor 1511.
1513 in FIG. 12 is a light guide.
In the embodiment of the invention, the laser echo which is not converged to the photoelectric sensor can be guided to the photoelectric sensor through the light guide lens, so that the deviation of the laser echo can be corrected, the signal-to-noise ratio of the system is improved, and the range finding blind area is reduced.
As still another embodiment of the present invention, the signal processing circuit 1512 includes a filter denoising circuit 15121 and a signal amplifying circuit 15122;
the photoelectric sensor 1511 is connected to a filter denoising circuit 15121, the filter denoising circuit 15121 is connected to a signal amplifying circuit 15122, and the signal amplifying circuit 15122 is connected to the signal conversion module 12;
the photoelectric sensor 1511 sends the echo electric signal to the filter denoising circuit 15121; the filtering denoising circuit 15121 performs filtering denoising processing on the echo electric signal to obtain a filtered denoised echo electric signal, and sends the filtered denoised echo electric signal to the signal amplifying circuit 15122, and the signal amplifying circuit 15122 performs signal amplifying processing on the filtered denoised echo electric signal to obtain a processed echo electric signal and sends the processed echo electric signal to the signal conversion module 12.
According to the embodiment of the invention, the filtering denoising circuit is used for filtering and denoising the echo electric signal to obtain the filtered and denoised echo electric signal, and the signal amplifying circuit is used for carrying out signal amplification on the filtered and denoised echo electric signal to obtain the processed echo electric signal, so that the signal-to-noise ratio of the echo electric signal can be improved to more than 20 db.
As still another embodiment of the present invention, the optical module 13 includes a transmitting lens 131 and a receiving lens 132;
the transmitting lens 131 converges the pulse laser, performs collimation adjustment on the pulse laser to obtain adjusted pulse laser, and transmits the adjusted pulse laser to a target object; the receiving lens 132 performs collimation adjustment on the laser echo to obtain an adjusted laser echo, and converges the adjusted laser echo to the echo detection module 15.
The emission lens 131 and the receiving lens 132 are formed by combining a plurality of lenses, that is, the emission lens 131 includes at least two lenses, and the receiving lens 132 includes at least two lenses. The emission lens 131 converges the pulse laser into a laser beam, ensures the laser energy concentration, and performs collimation adjustment on the pulse laser; the receiving lens 132 performs collimation adjustment on the laser echo, and converges the adjusted laser echo onto the photoelectric sensor 1511 in the echo detection module 15.
As yet another embodiment of the present invention, the optical module 13 further includes an optical housing 133;
the optical housing 133 performs stray light filtering treatment on the adjusted pulse laser, filters stray light outside the pulse laser band, and emits the pulse laser with the stray light filtered to a target object; the optical housing 133 performs stray light filtering processing on the laser echo, filters stray light outside the pulse laser band, and transmits the laser echo with the stray light filtered to the receiving lens 132.
As yet another embodiment of the present invention, the optical housing 133 includes an optical film.
In the embodiment of the invention, the optical housing 133 is internally provided with a layer of optical film, which can filter the stray light outside the pulse laser wave band, enhance the light transmittance of the pulse laser wave band, improve the signal to noise ratio of the system, and can also play roles of dust prevention, water prevention and the like.
As a further embodiment of the present invention, the signal conversion module 12 includes a two-channel analog-to-digital conversion unit;
one channel in the two-channel analog-to-digital conversion unit carries out analog-to-digital conversion on the echo electric signal to obtain a converted echo electric signal, and the other channel carries out analog-to-digital conversion on the reference signal to obtain a converted reference signal.
The two-channel analog-to-digital conversion unit may be a two-channel analog-to-digital converter.
According to the embodiment of the invention, the two-channel analog-to-digital conversion unit is used, one channel carries out analog-to-digital conversion on the echo electric signal to obtain the converted echo electric signal, and the other channel carries out analog-to-digital conversion on the reference signal to obtain the converted reference signal, so that the problem of aliasing of the near-distance signal can be solved, and the near-distance ranging blind area can be reduced.
As yet another embodiment of the present invention, the logic control module 11 includes a field programmable gate array (FPGA, field Programmable Gate Array).
Fig. 8 is a schematic structural diagram of a laser ranging system according to an embodiment of the present invention. Fig. 8 shows the laser transmitter module 14, the echo detection module 15, the optical housing 133 and the bottom circuit board 16 in a laser ranging system. The logic control module and the signal conversion module are integrated in the bottom circuit board 16, and the laser emission module 14 and the echo detection module 15 are separated by a partition. As shown in fig. 9, the laser emitting module 14 is a laser emitting array composed of individual laser emitting units 141. As shown in fig. 10, the laser emission unit 141 includes a laser diode 1411 and a laser driving circuit 1412. As shown in fig. 11, the echo detection module 15 is an echo detection array composed of individual echo ranging units 151. As shown in fig. 12, the echo detection unit 151 includes a signal processing circuit 1512, a photoelectric sensor, and a light guide 1513, wherein the photoelectric sensor is located inside the light guide 1513 and is connected to the signal processing circuit 1512, and the photoelectric sensor is not labeled in fig. 12 because the photoelectric sensor is shielded by the light guide 1513. Wherein the laser emitting units 141 are in one-to-one correspondence with the echo detecting units 151.
Fig. 13 is a schematic structural diagram of a laser ranging system according to another embodiment of the present invention. Fig. 13 shows the laser transmitting module 14, the echo detecting module 15, the transmitting lens 131, the receiving lens 132, the optical housing 133 and the bottom circuit board 16 in the laser ranging system. The logic control module and the signal conversion module are integrated within the bottom circuit board 16. Fig. 14 is a top view of a laser ranging system according to an embodiment of the present invention, as shown in fig. 14, pulse laser emitted by the laser emitting module 14 reaches a target object through the emitting lens and the optical housing 133, and the generated laser echo reaches the echo detecting module 15 through the optical housing 133 and the receiving lens.
It should be noted that the embodiments of the laser ranging system shown in the above figures are only examples and are not meant to be limiting of the laser ranging system, and may include more or fewer components than shown, or may be combined with certain components, or may be different components. For example, some means, components or modules, etc. known to those skilled in the art.
In the embodiments provided in this application, it should be understood that the disclosed laser ranging system may be implemented in other ways. For example, the laser ranging system embodiments described above are merely illustrative, and the division within the system internal logic control module, signal conversion module, optical module, laser transmitter module, and echo detection module, for example, are merely examples of one type of division, and may be implemented in other ways, or some features may be omitted or not performed. Alternatively, the connections shown or discussed as being made to each other, directly or through communication, may be made through any number of interfaces, such as electrical, mechanical, or other means.
The various parts described as separate components may or may not be physically separate.
The above embodiments are only for illustrating the technical solution of the present application, and are not limiting; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present application, and are intended to be included in the scope of the present application.
Claims (9)
1. A laser ranging system, comprising: the system comprises a logic control module, a signal conversion module, an optical module, a laser emission module and an echo detection module;
the logic control module is connected with the laser emission module, the laser emission module and the echo detection module are respectively connected with the signal conversion module, and the signal conversion module is connected with the logic control module;
the logic control module sends a control signal to the laser emission module; the laser emission module generates a driving signal according to the control signal, takes the driving signal as a reference signal, and sends the reference signal to the signal conversion module, and the laser emission module emits pulse laser according to the control signal; the pulse laser is emitted to a target object through the optical module, and a laser echo is generated; the laser echo is emitted to the echo detection module through the optical module; the echo detection module converts the laser echo into an echo electric signal and sends the echo electric signal to the signal conversion module; the signal conversion module carries out analog-to-digital conversion on the echo electric signal to obtain a converted echo electric signal, carries out analog-to-digital conversion on the reference signal to obtain a converted reference signal, and sends the converted reference signal and the converted echo electric signal to the logic control module; the logic control module obtains a distance measurement distance according to the converted reference signal and the converted echo electric signal;
the echo detection module comprises a preset number of echo detection units, the echo detection units comprise photoelectric sensors and signal processing circuits, and the echo detection units are in one-to-one correspondence with the laser emission units;
the photoelectric sensor is connected with the signal processing circuit, and the signal processing circuit is connected with the signal conversion module;
the laser echo is emitted to the photoelectric sensor through the optical module; the photoelectric sensor converts the laser echo into an echo electric signal and sends the echo electric signal to the signal processing circuit; the signal processing circuit performs filtering denoising and signal amplification processing on the echo electric signal to obtain a processed echo electric signal, and sends the processed echo electric signal to the signal conversion module; the signal conversion module performs analog-to-digital conversion on the processed echo electric signal to obtain a converted echo electric signal;
the logic control module performs digital filtering on the converted echo electric signal to obtain a filtered echo electric signal, performs threshold segmentation on the filtered echo electric signal to obtain a segmented echo electric signal, and obtains the centroid of the segmented echo electric signal to obtain a first centroid; the logic control module performs digital filtering on the converted reference signal to obtain a filtered reference signal, performs threshold segmentation on the filtered reference signal to obtain a segmented reference signal, and obtains the centroid of the segmented reference signal to obtain a second centroid; and the logic control module calculates the sampling time difference of the first centroid and the second centroid, and obtains the distance measurement distance according to the sampling time difference.
2. The laser ranging system of claim 1, wherein the laser emitting module comprises a preset number of laser emitting units, the laser emitting units comprising laser diodes and laser driving circuitry;
the logic control module is connected with the laser driving circuit, and the laser driving circuit is respectively connected with the laser diode and the signal conversion module;
the logic control module sends the control signal to the laser driving circuit, the laser driving circuit generates the driving signal according to the control signal, the driving signal is used as the reference signal, the reference signal is sent to the laser diode and the signal conversion module, and the reference signal drives the laser diode to emit the pulse laser.
3. The laser ranging system of claim 1, wherein the logic control module calculates a peak area of the segmented echo electrical signal, uses the peak area as laser echo energy, obtains a laser emission power adjustment signal according to the laser echo energy and the ranging distance, sends the laser emission power adjustment signal to the laser emission module, and the laser emission module adjusts laser emission power according to the laser emission power adjustment signal.
4. The laser ranging system of claim 1, wherein the signal processing circuit comprises a filtering denoising circuit and a signal amplification circuit;
the photoelectric sensor is connected with the filtering denoising circuit, the filtering denoising circuit is connected with the signal amplifying circuit, and the signal amplifying circuit is connected with the signal conversion module;
the photoelectric sensor sends the echo electric signal to the filtering denoising circuit; the filtering denoising circuit performs filtering denoising processing on the echo electric signal to obtain a filtered denoised echo electric signal, the filtered denoised echo electric signal is sent to the signal amplifying circuit, the signal amplifying circuit performs signal amplifying processing on the filtered denoised echo electric signal to obtain a processed echo electric signal, and the processed echo electric signal is sent to the signal conversion module.
5. The laser ranging system of claim 1, wherein the optical module comprises a transmitting lens and a receiving lens;
the transmitting lens converges the pulse laser, collimates and adjusts the pulse laser to obtain adjusted pulse laser, and transmits the adjusted pulse laser to the target object; and the receiving lens performs collimation adjustment on the laser echo to obtain an adjusted laser echo, and converges the adjusted laser echo to the echo detection module.
6. The laser ranging system of claim 5, wherein the optical module further comprises an optical enclosure;
the optical housing filters the adjusted pulse laser to remove stray light, filters the stray light outside the pulse laser band, and transmits the pulse laser with the stray light removed to the target object; and the optical housing performs stray light filtering treatment on the laser echo, filters stray light outside a pulse laser wave band, and transmits the laser echo with the stray light filtered to the receiving lens.
7. The laser ranging system of claim 6, wherein the optical enclosure comprises an optical film.
8. The laser ranging system of claim 1, wherein the signal conversion module comprises a two-channel analog-to-digital conversion unit;
and one channel in the two-channel analog-to-digital conversion unit performs analog-to-digital conversion on the echo electric signal to obtain the converted echo electric signal, and the other channel performs analog-to-digital conversion on the reference signal to obtain the converted reference signal.
9. The laser ranging system of claim 1, wherein the logic control module comprises a field programmable gate array.
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| WO2021062658A1 (en) * | 2019-09-30 | 2021-04-08 | 深圳市大疆创新科技有限公司 | Range measurement method and system for laser rangefinder, and storage medium |
| WO2021051733A1 (en) * | 2020-01-20 | 2021-03-25 | 深圳市速腾聚创科技有限公司 | Method and apparatus for laser ranging, storage medium, and lidar |
| CN113419250B (en) * | 2020-03-02 | 2024-06-04 | 华为技术有限公司 | Laser ranging system and laser ranging method |
| CN111596282B (en) * | 2020-04-19 | 2022-05-13 | 北京理工大学 | Pulse laser ranging echo amplitude automatic adjusting system |
| CN112782709B (en) * | 2020-12-28 | 2022-09-27 | 杭州电子科技大学 | Laser ranging method based on dynamic multi-threshold error correction |
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