Laser radar ranging system and control method thereof

Abstract

The invention provides a laser radar ranging system and a control method thereof. The laser radar ranging system comprises a control module, a signal transmitting module and a signal receiving module. The control module sends a driving signal after receiving an operation instruction, and the driving signal transmitting module transmits a first double-pulse laser signal corresponding to the driving signal to a measured object; an ignition signal is sent to the signal receiving module; the signal receiving module receives a second double-pulse laser signal reflected by the measured object to obtain an electric signal corresponding to the second double-pulse laser signal; performing amplification processing on the electric signal, and performing filtering processing on the electric signal based on a preset parameter to obtain a square wave signal; determining time interval data of the first double-pulse laser signal and the second double-pulse laser signal according to current time information corresponding to the ignition signal; and based on a preset software program, determining a distance measurement result according to the square wave signal and the time interval data. According to the system, the design complexity and the production cost of the existing laser radar ranging system can be reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of instruments and meters, and particularly relates to a lidar ranging system and a control method thereof. Background Art

[0002] In an environment with strong sunlight irradiation and multiple lidars shooting at each other, the receiving conversion circuit of the lidar will receive sunlight and the light from other lidars shooting at each other, resulting in a lot of interference signals on the received signal. As a result, there are many noise points on the point cloud map during imaging, leading to a low ranging accuracy.

[0003] The prior art generally uses a dual-pulse interval measurement module in hardware to decode pulse signals and output the signals to the main control chip, resulting in the disadvantages of complex design and high production cost in the existing lidar ranging system. Summary of the Invention

[0004] The purpose of the present invention is to provide a lidar ranging system and a control method thereof to alleviate the technical problems of complex design and high production cost in the existing lidar ranging system, and reduce the complexity and production cost of the lidar ranging system.

[0005] In a first aspect, an embodiment of the present invention provides a lidar ranging system, including: an FPGA control module, a signal transmitting module, and a signal receiving module that are connected in sequence; the FPGA control module is configured to, if an operation instruction is received, issue a driving signal corresponding to the signal transmission period in the operation instruction to drive the signal transmitting module to emit a first double-pulse laser signal corresponding to the driving signal to the object to be measured; and issue a firing signal corresponding to the first double-pulse laser signal to the signal receiving module; the signal receiving module is configured to receive a second double-pulse laser signal reflected by the object to be measured, perform photoelectric conversion on the second double-pulse laser signal to obtain an initial electrical signal corresponding to the second double-pulse laser signal; perform amplification processing on the initial electrical signal to obtain an amplified electrical signal; perform filtering processing on the amplified electrical signal based on preset parameters to obtain a square wave signal; and determine the time interval data between the first double-pulse laser signal and the second double-pulse laser signal according to the current time information corresponding to the firing signal; the FPGA control module is further configured to determine the ranging result based on a preset software program according to the square wave signal and the time interval data.

[0006] In a preferred embodiment of the present invention, the signal receiving module includes: an optical detector, a transimpedance amplifier circuit, a threshold setting circuit, a signal conversion circuit, and a TDC measurement circuit connected in sequence; the optical detector is configured to receive the second double-pulse laser signal and convert the second double-pulse laser signal into the initial electrical signal; the transimpedance amplifier circuit is configured to amplify the initial electrical signal based on a preset amplification factor to obtain the amplified electrical signal; the threshold setting circuit is configured to filter the amplified electrical signal based on the preset parameters to obtain the square wave signal; the TDC measurement circuit includes a TDC chip; the TDC chip is configured to determine the time interval data between the first double-pulse laser signal and the second double-pulse laser signal according to the time information corresponding to the ignition signal.

[0007] In a preferred embodiment of the present invention, the optical detector is an avalanche photodiode.

[0008] In a preferred embodiment of the present invention, the software program includes: a TDC control module; the TDC control module is configured to configure the register parameters in the TDC chip based on preset configuration parameters to set the working mode of the TDC chip to the calibration mode.

[0009] In a preferred embodiment of the present invention, the FPGA control module is further configured to issue a pulse signal corresponding to the pulse emission period in the operation instruction; the TDC chip is configured to calibrate the time interval data according to the pulse signal.

[0010] In a preferred embodiment of the present invention, the software program further includes: a coding recognition module connected to the TDC control module; the coding recognition module is configured to randomly match the square wave signal and the time interval data and output a matching result; according to the matching result, determine the distance between the lidar ranging system and the object to be measured and the pulse width data corresponding to the square wave signal, so as to determine the ranging result according to the distance and the pulse width data.

[0011] In a preferred embodiment of the present invention, the software program further includes: a reflectivity calibration module connected to the coding recognition module; the reflectivity calibration module is configured to determine the reflectivity data according to preset calibration data, the distance, and the pulse width data.

[0012] In a preferred embodiment of the present invention, the software program further includes: an Ethernet control module connected to the reflectivity calibration module; the Ethernet control module is configured to send the distance and the reflectivity data to the host computer; the host computer is configured to generate a point cloud image according to the distance and the reflectivity data and control a specified terminal to display the point cloud image.

[0013] In a preferred embodiment of the present invention, the above signal transmitting module includes: a laser diode; the laser diode is used to receive the above driving signal and emit a first double-pulse laser signal corresponding to the above driving signal to the object to be measured.

[0014] In a second aspect, an embodiment of the present invention further provides a control method for a lidar ranging system, which is applied to the above lidar ranging system; the method includes: if an operation instruction is received, the above FPGA control module issues a driving signal corresponding to the signal emission period in the above operation instruction to drive the above signal transmitting module to emit a first double-pulse laser signal corresponding to the above driving signal to the object to be measured; and, sending an ignition signal corresponding to the above first double-pulse laser signal to the above signal receiving module; receiving, by the above signal receiving module, a second double-pulse laser signal reflected by the above object to be measured, and performing photoelectric conversion on the above second double-pulse laser signal to obtain an initial electrical signal corresponding to the second double-pulse laser signal; amplifying the above initial electrical signal to obtain an amplified electrical signal; filtering the above amplified electrical signal based on preset parameters to obtain a square wave signal; and determining time interval data between the above first double-pulse laser signal and the above second double-pulse laser signal according to the current time information corresponding to the above ignition signal; based on a preset software program, the above FPGA control module determines a ranging result according to the above square wave signal and the above time interval data.

[0015] A lidar ranging system and its control method provided by an embodiment of the present invention include: an FPGA control module, a signal transmission module, and a signal reception module that are connected in sequence; the above-mentioned FPGA control module is configured to, if an operation instruction is received, issue a driving signal corresponding to the signal transmission period in the above-mentioned operation instruction to drive the above-mentioned signal transmission module to transmit a first double-pulse laser signal corresponding to the above-mentioned driving signal to the object to be measured; and issue an ignition signal corresponding to the above-mentioned first double-pulse laser signal to the above-mentioned signal reception module; the above-mentioned signal reception module is configured to receive the second double-pulse laser signal reflected by the above-mentioned object to be measured, perform optoelectronic conversion on the above-mentioned second double-pulse laser signal to obtain an initial electrical signal corresponding to the second double-pulse laser signal; perform amplification processing on the above-mentioned initial electrical signal to obtain an amplified electrical signal; perform filtering processing on the above-mentioned amplified electrical signal based on preset parameters to obtain a square wave signal; and determine the time interval data between the above-mentioned first double-pulse laser signal and the above-mentioned second double-pulse laser signal according to the current time information corresponding to the above-mentioned ignition signal; the above-mentioned FPGA control module is further configured to determine the ranging result based on a preset software program according to the above-mentioned square wave signal and the above-mentioned time interval data. This system determines the ranging result based on a preset software program by the FPGA control module according to the square wave signal and the time interval data, so the operations at the hardware level are transformed into those at the software level, reducing the design complexity and production cost of the existing lidar ranging system.

[0016] Other features and advantages disclosed in this embodiment will be described in the subsequent specification, or, some features and advantages can be inferred from the specification or determined without doubt, or can be known by implementing the above technologies of the present disclosure.

[0017] To make the above objects, features, and advantages of the present disclosure more obvious and understandable, the following specifically enumerates preferred embodiments and, in conjunction with the accompanying drawings, provides a detailed description as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0019] Figure 1 It is a schematic structural diagram of a lidar ranging system provided by an embodiment of the present invention;

[0020] Figure 2 It is a schematic structural diagram of another lidar ranging system provided by an embodiment of the present invention;

[0021] Figure 3 Schematic diagram of the composition of a software program for a lidar ranging system provided by an embodiment of the present invention;

[0022] Figure 4 Schematic flowchart of a control method for a lidar ranging system provided by an embodiment of the present invention.

[0023] Icons: 11 - FPGA control module; 12 - signal transmission module; 13 - signal reception module; 21 - optical detector; 22 - transimpedance amplifier circuit; 23 - threshold setting circuit; 24 - signal conversion circuit; 25 - TDC measurement circuit; 26 - laser diode; 27 - laser driver circuit; 31 - TDC control module; 32 - coding recognition module; 33 - reflectivity calibration module; 34 - Ethernet control module; 35 - host computer; 36 - reception control module. Detailed implementation manners

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Generally, the components of the embodiments of the present invention described and illustrated in the accompanying drawings here can be arranged and designed in various different configurations.

[0025] Currently, the prior art generally uses a dual - pulse interval measurement module in hardware to decode pulse signals and output signals to the main control chip, resulting in the disadvantages of complex design and high production cost in the existing lidar ranging system.

[0026] Based on this, the embodiments of the present invention provide a lidar ranging system and its control method. The system determines the ranging result based on a preset software program by the FPGA control module according to the square - wave signal and time - interval data, so the operations at the hardware level are transformed into those at the software level, reducing the complexity of the design and the production cost of the existing lidar ranging system. To facilitate the understanding of the embodiments of the present invention, a lidar ranging system disclosed in the embodiments of the present invention will be introduced in detail first.

[0027] Embodiment 1

[0028] In this embodiment, Figure 1 Schematic diagram of the structure of a lidar ranging system provided by an embodiment of the present invention.

[0029] As Figure 1 can be seen, the lidar ranging system includes: an FPGA control module 11, a signal transmission module 12, and a signal reception module 13 that are connected in sequence.

[0030] In this embodiment, the above-mentioned FPGA control module 11 is configured to, if an operation instruction is received, issue a driving signal corresponding to the signal emission period in the above-mentioned operation instruction to drive the above-mentioned signal emission module 12 to emit a first double-pulse laser signal corresponding to the above-mentioned driving signal to the object to be measured; and, send an ignition signal corresponding to the above-mentioned first double-pulse laser signal to the above-mentioned signal receiving module 13; the above-mentioned signal receiving module 13 is configured to receive the second double-pulse laser signal reflected by the above-mentioned object to be measured, perform photoelectric conversion on the above-mentioned second double-pulse laser signal to obtain an initial electrical signal corresponding to the second double-pulse laser signal; perform amplification processing on the above-mentioned initial electrical signal to obtain an amplified electrical signal; perform filtering processing on the above-mentioned amplified electrical signal based on preset parameters to obtain a square wave signal; and determine the time interval data between the above-mentioned first double-pulse laser signal and the above-mentioned second double-pulse laser signal according to the current time information corresponding to the above-mentioned ignition signal; the above-mentioned FPGA control module 11 is further configured to determine the ranging result based on a preset software program according to the above-mentioned square wave signal and the above-mentioned time interval data.

[0031] In this embodiment, the above-mentioned signal emission module 12 includes: a laser diode 26; the above-mentioned laser diode 26 is configured to receive the above-mentioned driving signal and emit a first double-pulse laser signal corresponding to the above-mentioned driving signal to the object to be measured.

[0032] Further, the above-mentioned laser diode 26 is driven by a laser driving circuit 27.

[0033] For ease of understanding, Figure 2 is a schematic structural diagram of another lidar ranging system provided by an embodiment of the present invention.

[0034] As Figure 2 can be seen, the above-mentioned signal receiving module 13 includes: an optical detector 21, a transimpedance amplifier circuit 22, a threshold setting circuit 23, a signal conversion circuit 24, and a TDC measurement circuit 25 connected in sequence; the above-mentioned optical detector 21 is configured to receive the above-mentioned second double-pulse laser signal and convert the above-mentioned second double-pulse laser signal into the above-mentioned initial electrical signal; the above-mentioned transimpedance amplifier circuit 22 is configured to perform amplification processing on the above-mentioned initial electrical signal based on a preset amplification factor to obtain the above-mentioned amplified electrical signal; the above-mentioned threshold setting circuit 23 is configured to perform filtering processing on the above-mentioned amplified electrical signal based on the above-mentioned preset parameters to obtain the above-mentioned square wave signal; the above-mentioned TDC measurement circuit 25 includes a TDC chip; the above-mentioned TDC chip is configured to determine the time interval data between the above-mentioned first double-pulse laser signal and the above-mentioned second double-pulse laser signal according to the time information corresponding to the above-mentioned ignition signal.

[0035] Further, the above-mentioned optical detector is an avalanche photodiode.

[0036] For ease of understanding, Figure 3 FIG. is a schematic diagram of the composition of a software program of a lidar ranging system provided by an embodiment of the present invention.

[0037] As Figure 3 seen, the above software program includes: a TDC control module 31; the TDC control module 31 is used to configure the register parameters in the TDC chip based on preset configuration parameters, so as to set the working mode of the TDC chip to a calibration mode.

[0038] Furthermore, the FPGA control module 11 is further used to issue a pulse signal corresponding to the pulse emission period in the operation instruction; the TDC chip is used to calibrate the time interval data according to the pulse signal.

[0039] Furthermore, the above software program further includes: an encoding recognition module 32 connected to the TDC control module 31; the encoding recognition module 32 is used to randomly match the square wave signal and the time interval data, and output a matching result; according to the matching result, determine the distance between the lidar ranging system and the measured object and the pulse width data corresponding to the square wave signal, so as to determine the ranging result according to the distance and the pulse width data.

[0040] Furthermore, the above software program further includes: a reflectivity calibration module 33 connected to the encoding recognition module 32; the reflectivity calibration module 33 is used to determine reflectivity data according to preset calibration data, the distance, and the pulse width data.

[0041] Furthermore, the above software program further includes: a reception control module 36 connected to the signal reception module 13.

[0042] Furthermore, the above software program further includes: an Ethernet control module 34 connected to the reflectivity calibration module 33; the Ethernet control module 34 is used to send the distance and the reflectivity data to the host computer 35; the host computer 35 is used to generate a point cloud image according to the distance and the reflectivity data, and control a specified terminal to display the point cloud image.

[0043] A lidar ranging system provided by an embodiment of the present invention includes: an FPGA control module, a signal transmitting module, and a signal receiving module that are connected in sequence; the FPGA control module is configured to, if an operation instruction is received, send a driving signal corresponding to the signal transmission period in the operation instruction to drive the signal transmitting module to emit a first double-pulse laser signal corresponding to the driving signal to an object to be measured; and send an ignition signal corresponding to the first double-pulse laser signal to the signal receiving module; the signal receiving module is configured to receive a second double-pulse laser signal reflected by the object to be measured, perform photoelectric conversion on the second double-pulse laser signal to obtain an initial electrical signal corresponding to the second double-pulse laser signal; perform amplification processing on the initial electrical signal to obtain an amplified electrical signal; perform filtering processing on the amplified electrical signal based on preset parameters to obtain a square wave signal; and determine time interval data between the first double-pulse laser signal and the second double-pulse laser signal according to the current time information corresponding to the ignition signal; the FPGA control module is further configured to determine a ranging result based on a preset software program according to the square wave signal and the time interval data. The system determines the ranging result based on the preset software program according to the square wave signal and the time interval data through the FPGA control module, so the operations at the hardware level are converted into operations at the software level, reducing the design complexity and production cost of the existing lidar ranging system.

[0044] Embodiment 2

[0045] Based on Embodiment 1, Figure 4 It is a schematic flowchart of a control method for a lidar ranging system provided by an embodiment of the present invention. The method is for the above-mentioned lidar ranging system.

[0046] As Figure 4 can be seen, the method includes:

[0047] Step S401: If an operation instruction is received, send, through the FPGA control module, a driving signal corresponding to the signal transmission period in the operation instruction to drive the signal transmitting module to emit a first double-pulse laser signal corresponding to the driving signal to an object to be measured; and send an ignition signal corresponding to the first double-pulse laser signal to the signal receiving module.

[0048] Step S402: Receive the second double-pulse laser signal reflected by the object to be measured through the above signal receiving module, perform photoelectric conversion on the second double-pulse laser signal to obtain an initial electrical signal corresponding to the second double-pulse laser signal; amplify the initial electrical signal to obtain an amplified electrical signal; perform filtering processing on the amplified electrical signal based on preset parameters to obtain a square wave signal; and determine the time interval data between the first double-pulse laser signal and the second double-pulse laser signal according to the current time information corresponding to the ignition signal.

[0049] Step S403: Determine the ranging result based on the preset software program through the above FPGA control module according to the square wave signal and the time interval data.

[0050] A control method for a lidar ranging system provided by an embodiment of the present invention includes: if an operation instruction is received, send a driving signal corresponding to the signal emission period in the operation instruction through the above FPGA control module to drive the signal emission module to emit a first double-pulse laser signal corresponding to the driving signal to the object to be measured; and send an ignition signal corresponding to the first double-pulse laser signal to the signal receiving module; receive the second double-pulse laser signal reflected by the object to be measured through the above signal receiving module, perform photoelectric conversion on the second double-pulse laser signal to obtain an initial electrical signal corresponding to the second double-pulse laser signal; amplify the initial electrical signal to obtain an amplified electrical signal; perform filtering processing on the amplified electrical signal based on preset parameters to obtain a square wave signal; and determine the time interval data between the first double-pulse laser signal and the second double-pulse laser signal according to the current time information corresponding to the ignition signal; determine the ranging result based on the preset software program through the above FPGA control module according to the square wave signal and the time interval data. This method determines the ranging result based on the preset software program through the FPGA control module according to the square wave signal and the time interval data, so the operations at the hardware level are transformed into those at the software level, reducing the design complexity and production cost of the existing lidar ranging system.

[0051] Finally, it should be noted that the above embodiments are only specific implementation manners of the present invention, used to illustrate the technical solutions of the present invention, rather than limiting it. The protection scope of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that any person skilled in the technical field can still modify the technical solutions described in the foregoing embodiments, or can easily think of changes, or perform equivalent replacements on some of the technical features; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the above-mentioned claims.

Claims

1. A lidar ranging system, characterized in that, Including: An FPGA control module, a signal transmitting module, and a signal receiving module connected in sequence; The FPGA control module is configured to, if an operation instruction is received, issue a driving signal corresponding to the signal transmission period in the operation instruction to drive the signal transmitting module to emit a first double-pulse laser signal corresponding to the driving signal to the object to be measured; and, issue a firing signal corresponding to the first double-pulse laser signal to the signal receiving module; The signal receiving module is configured to receive the second double-pulse laser signal reflected by the object to be measured, and perform optoelectronic conversion on the second double-pulse laser signal to obtain an initial electrical signal corresponding to the second double-pulse laser signal; Perform amplification processing on the initial electrical signal to obtain an amplified electrical signal; Perform filtering processing on the amplified electrical signal based on preset parameters to obtain a square wave signal; and determine the time interval data between the first double-pulse laser signal and the second double-pulse laser signal according to the current time information corresponding to the firing signal; The FPGA control module is further configured to determine a ranging result based on a preset software program according to the square wave signal and the time interval data.

2. The lidar ranging system according to claim 1, wherein, The signal receiving module includes: an optical detector, a transimpedance amplifier circuit, a threshold setting circuit, a signal conversion circuit, and a TDC measurement circuit connected in sequence; The optical detector is configured to receive the second double-pulse laser signal and convert the second double-pulse laser signal into the initial electrical signal; The transimpedance amplifier circuit is configured to perform amplification processing on the initial electrical signal based on a preset amplification factor to obtain the amplified electrical signal; The threshold setting circuit is configured to perform filtering processing on the amplified electrical signal based on the preset parameters to obtain the square wave signal; The TDC measurement circuit includes a TDC chip; the TDC chip is configured to determine the time interval data between the first double-pulse laser signal and the second double-pulse laser signal according to the time information corresponding to the firing signal.

3. The lidar ranging system according to claim 2, characterized in that, The optical detector is an avalanche photodiode.

4. The lidar ranging system according to claim 2, wherein, The software program includes: a TDC control module; The TDC control module is configured to configure the register parameters in the TDC chip based on preset configuration parameters to set the working mode of the TDC chip to a calibration mode.

5. The lidar ranging system according to claim 4, wherein The FPGA control module is further configured to issue a pulse signal corresponding to the pulse emission period in the operation instruction; The TDC chip is configured to calibrate the time interval data according to the pulse signal.

6. The lidar ranging system according to claim 4, wherein The software program further includes: a coding recognition module connected to the TDC control module; The coding recognition module is configured to randomly match the square wave signal and the time interval data, and output a matching result; determine the distance between the lidar ranging system and the object to be measured and the pulse width data corresponding to the square wave signal according to the matching result, so as to determine the ranging result according to the distance and the pulse width data.

7. The lidar ranging system according to claim 6, wherein The software program further includes: a reflectivity calibration module connected to the coding recognition module; The reflectivity calibration module is used to determine reflectivity data according to preset calibration data, the distance, and the pulse width data.

8. The lidar ranging system according to claim 7, characterized in that, The software program further includes: an Ethernet control module connected to the reflectivity calibration module; The Ethernet control module is used to send the distance and the reflectivity data to a host computer; The host computer is used to generate a point cloud image according to the distance and the reflectivity data, and control a specified terminal to display the point cloud image.

9. The lidar ranging system according to claim 1, wherein The signal transmitting module includes: a laser diode; The laser diode is used to receive the driving signal and emit a first double-pulse laser signal corresponding to the driving signal to the object to be measured.

10. A control method for a lidar ranging system, characterized in that, Applied to the lidar ranging system according to any one of claims 1 to 9; the method includes: If an operation instruction is received, the FPGA control module issues a driving signal corresponding to the signal emission period in the operation instruction to drive the signal transmitting module to emit a first double-pulse laser signal corresponding to the driving signal to the object to be measured; and, issue a firing signal corresponding to the first double-pulse laser signal to the signal receiving module; Receiving, by the signal receiving module, a second double-pulse laser signal reflected by the object to be measured, and performing optoelectronic conversion on the second double-pulse laser signal to obtain an initial electrical signal corresponding to the second double-pulse laser signal; amplifying the initial electrical signal to obtain an amplified electrical signal; performing filtering processing on the amplified electrical signal based on preset parameters to obtain a square wave signal; and determining time interval data between the first double-pulse laser signal and the second double-pulse laser signal according to the current time information corresponding to the firing signal; Determining, by the FPGA control module based on a preset software program, a ranging result according to the square wave signal and the time interval data.

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