CN110806586A - Non-scanning linear frequency modulation continuous wave speed and distance measuring laser three-dimensional imaging method and device - Google Patents

Non-scanning linear frequency modulation continuous wave speed and distance measuring laser three-dimensional imaging method and device Download PDF

Info

Publication number
CN110806586A
CN110806586A CN202010016103.2A CN202010016103A CN110806586A CN 110806586 A CN110806586 A CN 110806586A CN 202010016103 A CN202010016103 A CN 202010016103A CN 110806586 A CN110806586 A CN 110806586A
Authority
CN
China
Prior art keywords
target
frequency
signal
distance
speed
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
CN202010016103.2A
Other languages
Chinese (zh)
Other versions
CN110806586B (en
Inventor
职亚楠
孙建锋
潘卫清
戴恩文
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sun Jianfeng
Original Assignee
Hangzhou Erae Technology Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hangzhou Erae Technology Co Ltd filed Critical Hangzhou Erae Technology Co Ltd
Priority to CN202010016103.2A priority Critical patent/CN110806586B/en
Publication of CN110806586A publication Critical patent/CN110806586A/en
Application granted granted Critical
Publication of CN110806586B publication Critical patent/CN110806586B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • 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
    • G01S17/32—Systems determining position data of a target for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated
    • 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
    • G01S17/50—Systems of measurement based on relative movement of target
    • G01S17/58—Velocity or trajectory determination systems; Sense-of-movement determination systems
    • 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
    • G01S17/88—Lidar systems specially adapted for specific applications
    • G01S17/89—Lidar systems specially adapted for specific applications for mapping or imaging

Abstract

The invention discloses a non-scanning linear frequency modulation continuous wave speed and distance measuring laser three-dimensional imaging method and a device, wherein an output light beam generated by a linear frequency modulation continuous laser light source of a radar platform is divided into a local oscillator light beam and a signal light beam; the method comprises the steps of transmitting a signal beam to a target and receiving an echo beam of the target, carrying out coherent light mixing on the echo beam and a local oscillator beam through a space optical bridge, carrying out parallel balanced receiving by using a balanced detector to obtain an intermediate frequency signal, reading the intermediate frequency signal by using a dual-channel focal plane readout circuit, carrying out filtering processing and sampling processing to obtain sampling data, processing the sampling data by using a field programmable gate array to realize parallel synchronous measurement of the distance and the speed of the target, and finally combining an image processor to respectively construct a three-dimensional image. The method can obtain the distance-intensity image containing the gray scale information of the remote target and the spatial three-dimensional geometric position relation, and can also obtain the magnitude and the direction of the radial speed of the relative motion of the radar platform and the target.

Description

Non-scanning linear frequency modulation continuous wave speed and distance measuring laser three-dimensional imaging method and device
Technical Field
The invention relates to the technical field of laser radars, in particular to a laser three-dimensional imaging method and device for measuring speed and distance of non-scanning linear frequency-modulated continuous waves。
Background
The laser three-dimensional imaging radar is an active detection technology capable of accurately and quickly acquiring three-dimensional space information of a target, has high imaging space resolution, has strong adaptability to target characteristics and use environment, has unique technical advantages in the aspects of target identification, classification and high-precision three-dimensional imaging and measurement, and is an important means for a maneuvering platform (including vehicle-mounted, airborne, satellite-mounted and the like) to quickly acquire the high-resolution three-dimensional target image information.
The three-dimensional imaging laser radar can be divided into a scanning type and a non-scanning type according to the imaging mode. The scanning type three-dimensional imaging laser radar uses a unit or linear array detector to obtain the height information of each point in a field of view by using two-dimensional point-by-point scanning or one-dimensional line-by-line scanning, and finally performs synthesis processing. The scanning laser imaging radar has the defects of low imaging speed, high laser working frequency, large transmitting power consumption, low imaging resolution and precision, low data splicing precision and the like. When the scanning type laser three-dimensional imaging radar is loaded on a maneuvering platform, the vibration or shake of the platform easily causes data splicing difficulty and seriously affects the measurement precision, so the scanning type laser three-dimensional imaging radar is not suitable for high-precision maneuvering platform three-dimensional imaging application. The scanless laser three-dimensional imaging radar has the advantages of high imaging speed, high frame frequency, high resolution and the like, overcomes the defects of large volume, heavy mass and poor reliability of a scanning type, and plays a vital role in the application of space target relative navigation with higher requirements on real-time performance and volume.
The non-scanning laser three-dimensional imaging radar is divided according to a detection system, and generally adopts two modes of incoherent light direct detection and coherent light heterodyne receiving detection. The incoherent direct detection mode is that pulse laser intensity modulation is adopted at a transmitting terminal, and a photoelectric detection array is adopted at a receiving terminal for direct detection of optical pulses, wherein the common modes mainly include a flash mode based on a linear mode avalanche photodiode (LM-APD) array, a photon counting mode based on a Geiger mode avalanche photodiode (GM-APD) array and a mixing array detection mode based on linear amplitude modulation continuous waves. In the later 90 s of the last century, a Lincoln laboratory of the American Massachusetts institute of technology, Inc. firstly develops a laser three-dimensional imaging radar research based on a GM-APD array under the support of an American DARPA and an air force laboratory, the research and development of GM-APD focal plane array devices with pixel numbers of 4 × 4, 32 × 32, 128 × 32 and 256 × 256 respectively are reported in sequence until 2002, and meanwhile, a plurality of generations of airborne laser three-dimensional imaging radar systems are developed. A frequency mixing array detection laser three-dimensional imaging radar FOPEN based on linear amplitude modulation continuous waves is developed in the United states army laboratory in 2007, a 1550nm continuous output laser diode is adopted, a Direct Digital Synthesizer (DDS) is adopted to achieve intensity modulation, a 640 x 512 pixel array EBAPS detector is adopted as a signal receiving end, the field angle is 35 degrees x 35 degrees, and the distance measurement precision is less than 3 cm. Although the incoherent direct detection mode has high imaging speed, does not need a complex scanning mechanism, and has the capability of flash three-dimensional imaging, the incoherent direct detection mode also requires that the echo power of the laser received by the system is uniformly distributed on each detection pixel, and under the condition of the same laser emission total power and receiving aperture, the more detection pixels are, the smaller the echo power dispersed on each pixel is, so that the detection sensitivity of the area array imaging system is generally lower, and the incoherent direct detection mode is generally only suitable for three-dimensional imaging detection at a short distance. Although single photon detection technology is mature and detection sensitivity is higher, the cost of the device is too high.
The coherent heterodyne detection method adopts local oscillator laser and echo beam laser to perform heterodyne technology on a photoelectric detector, can naturally inhibit background noise and improve the signal-to-noise ratio, and is typically a linear frequency modulation continuous wave coherent laser radar. In 2012, Brian W. Krause adopts a high-speed CCD area array for receiving, and realizes non-scanning linear frequency modulation continuous wave coherent three-dimensional imaging at a distance of 1 meter indoors through motion compensation. However, the application of the coherent detection technology to the non-scanning three-dimensional imaging of the long-distance target has not been reported so far. In addition, all the existing scanning-free laser three-dimensional imaging radars, including a phase discrimination type, a polarization modulation type, a gain modulation type, a fringe tube detector type and the like, cannot realize direct measurement of target speed.
Disclosure of Invention
The invention aims to provide a laser three-dimensional imaging method and device for speed and distance measurement of a non-scanning linear frequency-modulated continuous wave. The invention can not only obtain the distance-intensity image containing the gray information of the remote target and the spatial three-dimensional geometric position relation, but also obtain the size and the direction of the radial speed of the relative motion of the radar platform and the target, and has the advantages of small volume, light weight, high resolution, high precision and undistorted three-dimensional imaging of the dynamic target.
The technical scheme of the invention is as follows: a non-scanning linear frequency modulation continuous wave speed and distance measuring laser three-dimensional imaging method is characterized in that an output light beam generated by a linear frequency modulation continuous laser light source of a radar platform is divided into a local oscillator light beam and a signal light beam through a beam splitter; the method comprises the steps of transmitting a signal beam to a target and receiving an echo beam of the target, carrying out coherent light mixing on the echo beam and a local oscillator beam through a space optical bridge, carrying out parallel balanced receiving by using a dual-channel focal plane array balanced detector to obtain an intermediate frequency signal containing target distance and speed information, reading the intermediate frequency signal by using a dual-channel focal plane reading circuit, carrying out filtering processing and sampling processing on the intermediate frequency signal to obtain sampling data, carrying out real-time parallel fast Fourier transform and cross-spectrum processing on the sampling data by using a field programmable gate array to realize parallel synchronous measurement of target distance and speed, and finally combining an image processor to respectively construct a distance-intensity three-dimensional point cloud image and a distance-speed three-dimensional point cloud image.
The synchronous measurement of the target distance and speed is realized by the laser three-dimensional imaging method for speed measurement and ranging of the scanless linear frequency modulation continuous wave, specifically, the synchronous measurement of the target distance and speed is realized by respectively carrying out Fourier transform on an in-phase signal and an orthogonal signal output by a dual-channel focal plane array balanced detector, then carrying out cross-spectrum processing to obtain a Doppler frequency spectrum, then taking an imaginary part of the Doppler frequency spectrum, extracting the position and the positive and negative of a peak value in the Doppler frequency spectrum by using a gravity center method to obtain Doppler frequency shift generated by the relative motion of a radar platform and a target, and then obtaining the size and the direction of the radial speed of the relative motion of the.
In the above three-dimensional imaging method using non-scanning chirped continuous wave speed and distance measurement laser, an output light beam generated by the chirped continuous laser light source is a frequency-linearly modulated continuous coherent laser, a symmetric triangular wave is used for linear modulation, the frequency of a modulation signal changes in a symmetric triangular shape with time, in a period, the first half is a positive frequency modulation, the second half is a negative frequency modulation, and the light field is represented as:
Figure DEST_PATH_IMAGE002
，
wherein the content of the first and second substances,
Figure DEST_PATH_IMAGE004
is the time of day or the like,
Figure DEST_PATH_IMAGE006
is the amplitude of the wave, and,
Figure DEST_PATH_IMAGE008
in order to have a frequency-modulated period,
Figure DEST_PATH_IMAGE010
in order to frequency-modulate the initial frequency,in order to be able to modulate the frequency rate,in order to adjust the bandwidth of the frequency band,
Figure DEST_PATH_IMAGE016
is as follows
Figure DEST_PATH_IMAGE018
The initial phase of the rising segment of the laser frequency modulation pulse,is as followsInitial phase of down section of frequency-modulated laser pulse；
Split by a 1X 2 beam splitter, a small part of energy is used as a local oscillation light beam which is time delay
Figure DEST_PATH_IMAGE023
The optical field is represented as:
Figure DEST_PATH_IMAGE025
，
wherein the content of the first and second substances,is the amplitude of the local oscillator beam,
Figure DEST_PATH_IMAGE029
is the noise phase of the local oscillator beam;
most energy is used as a signal beam, the signal beam is transmitted to a target through a space optical circulator and an optical telescope, and an echo beam of the target is received by the optical telescope; after passing through the space optical circulator, the echo beam is on the target plane
Figure DEST_PATH_IMAGE031
A scattering target
Figure DEST_PATH_IMAGE033
Time delay of
Figure DEST_PATH_IMAGE035
The linear frequency modulated signal of (a);
in the radar-target coordinate system
Figure DEST_PATH_IMAGE037
In (1),
Figure DEST_PATH_IMAGE039
has the coordinates of
Figure DEST_PATH_IMAGE041
，
The radar and the target
Figure 592094DEST_PATH_IMAGE033
Distance between each other
Figure DEST_PATH_IMAGE043
Expressed as:
Figure DEST_PATH_IMAGE045
，
for the purpose of remote detection of the object,
Figure DEST_PATH_IMAGE047
，
Figure DEST_PATH_IMAGE049
and thus;
targetTime delay of echo light beam
Figure DEST_PATH_IMAGE055
Expressed as:
Figure DEST_PATH_IMAGE057
，
wherein the content of the first and second substances,
Figure DEST_PATH_IMAGE059
it is the speed of light that is,
Figure DEST_PATH_IMAGE061
is a radar platform and target
Figure DEST_PATH_IMAGE063
The radial speed of the relative movement is,
Figure DEST_PATH_IMAGE065
is a radar platform and targetCaused by radial velocity of relative motionThe frequency of the doppler shift,
by the resulting time delayOn the target plane
Figure DEST_PATH_IMAGE071
A scattering target
Figure DEST_PATH_IMAGE073
The light field of the echo light beam of (a) is expressed as:
Figure DEST_PATH_IMAGE075
，
wherein the content of the first and second substances,
Figure DEST_PATH_IMAGE077
is the amplitude of the echo light beam,
Figure DEST_PATH_IMAGE079
is the noise phase of the echo beam.
In the above non-scanning linear frequency modulation continuous wave velocity and distance measuring laser three-dimensional imaging method, the first step on the target plane
Figure DEST_PATH_IMAGE081
A scattering target
Figure DEST_PATH_IMAGE083
The optical field after the echo light beam and the local oscillator light beam are combined by the 2 × 490-degree spatial optical bridge is represented as:
，
the four outputs after being mixed by the 2 × 490-degree spatial optical bridge are respectively:
Figure DEST_PATH_IMAGE087
，
Figure DEST_PATH_IMAGE089
，
wherein the content of the first and second substances,is a mixing of the noise phases and is,
Figure DEST_PATH_IMAGE093
is a direct current quantity related to the echo beam;
Figure DEST_PATH_IMAGE095
is a direct current quantity related to the local oscillator beam,
Figure DEST_PATH_IMAGE097
is the optical heterodyne receiver directivity function;
in-phase signals and orthogonal signals with orthogonal characteristics output by the space optical bridge are respectively received by the 2 XMXN unit dual-channel focal plane array balanced detector to obtain a target containing M XN points of a target plane
Figure 346030DEST_PATH_IMAGE063
Intermediate frequency signals of distance and velocity information; the intermediate frequency signal is an in-phase signal and a quadrature signal output by two channels of the 2 XMXN unit dual-channel focal plane array balanced detector, and the signals are respectively:
Figure DEST_PATH_IMAGE099
，
Figure DEST_PATH_IMAGE101
，
wherein
Figure DEST_PATH_IMAGE103
Photoelectric detection unit for receiving in-phase signal channel in dual-channel focal plane array balanced detector
Figure DEST_PATH_IMAGE105
The response rate of (a) to (b),
Figure DEST_PATH_IMAGE107
photoelectric detection unit for receiving orthogonal signal channel in dual-channel focal plane array balanced detector
Figure DEST_PATH_IMAGE109
The response rate of (a) to (b),
Figure DEST_PATH_IMAGE111
and
Figure DEST_PATH_IMAGE113
noise phases of the in-phase signal and the quadrature signal, respectively;
the amplitudes of the in-phase signal and the quadrature signal are simplified:
Figure DEST_PATH_IMAGE115
,
the inphase signal and the orthogonal signal output by the dual-channel focal plane array balanced detector are simplified as follows:
，
Figure DEST_PATH_IMAGE119
；
the outputs of the in-phase signal channel and the orthogonal signal channel photoelectric detection units are respectively read out intermediate frequency signals through a dual-channel focal plane readout circuit, and after the intermediate frequency signals are subjected to band-pass filter filtering processing, analog-to-digital conversion is completed through a high-speed analog-to-digital converter, and then the signals are collected by a field programmable gate array, and Doppler frequency shift measurement and distance measurement are respectively performed:
specifically, firstly, the two channels of data are respectively subjected to fast fourier transform, and the in-phase signal channel fourier transform is expressed as:
Figure DEST_PATH_IMAGE121
，
the orthogonal signal path fourier transform is represented as:
Figure DEST_PATH_IMAGE123
，
performing cross-spectrum processing on the two channels:
Figure DEST_PATH_IMAGE125
，
finally, only the imaginary part is taken to obtain
Figure DEST_PATH_IMAGE127
，
Extracting the peak position and the positive and negative of the frequency spectrum by a gravity center method to respectively obtain frequency values in the positive frequency modulation process and the negative frequency modulation process
Figure DEST_PATH_IMAGE129
：
Figure DEST_PATH_IMAGE131
，
From the above formula, one can obtain:
Figure DEST_PATH_IMAGE133
，
in the above formula, the first and second carbon atoms are,
Figure DEST_PATH_IMAGE135
is the frequency value in the forward frequency modulation process,
Figure DEST_PATH_IMAGE137
is the frequency value in the negative frequency modulation process; because the Doppler frequency shift is in direct proportion to the radial velocity of the relative motion of the radar platform and the target, the positive and negative Doppler frequency shifts are related to the direction of the radial velocity of the relative motion of the radar platform and the target, the positive frequency shift represents the relative motion of the radar platform and the target, and the negative frequency shift represents the radarThe platform moves back to the target;
therefore, the radar platform and the target can be obtained by Doppler frequency shift
Figure DEST_PATH_IMAGE138
The magnitude and direction of the radial velocity of the relative motion are expressed as
Figure DEST_PATH_IMAGE140
，
Wherein
Figure DEST_PATH_IMAGE142
Is the output beam wavelength;
obtaining the second on the target plane from the above formula
Figure DEST_PATH_IMAGE144
A scattering target
Figure DEST_PATH_IMAGE146
Is a distance of
Figure DEST_PATH_IMAGE148
：
Figure DEST_PATH_IMAGE150
。
In the non-scanning linear frequency modulation continuous wave speed and distance measuring laser three-dimensional imaging method, the first step is that on a target plane
Figure DEST_PATH_IMAGE152
A scattering target
Figure DEST_PATH_IMAGE154
The return beam deflection angle of
Figure DEST_PATH_IMAGE156
Then optical heterodyne receives the directional function
Figure DEST_PATH_IMAGE158
Comprises the following steps:
Figure DEST_PATH_IMAGE160
，
wherein the content of the first and second substances,
Figure DEST_PATH_IMAGE162
in the form of a first order bezier function,is the magnification factor of the optical telescope,is the diameter of the photodetecting unit, so the reception field angle is expressed as:
m multiplied by N is the number of pixels of a single channel of the dual-channel focal plane array balanced detector;
the range resolution is expressed as:
，
wherein the content of the first and second substances,
Figure DEST_PATH_IMAGE172
it is the speed of light that is,
Figure DEST_PATH_IMAGE174
is a linear frequency modulation bandwidth;
the velocity resolution is expressed as:
Figure DEST_PATH_IMAGE176
，
wherein the content of the first and second substances,in order to have a frequency-modulated period,is a primary frequency modulationThe frequency of the start-up is,
Figure DEST_PATH_IMAGE182
in order to frequency-modulate the initial wavelength,
Figure DEST_PATH_IMAGE184
is the frequency modulation rate.
According to the scanning-free linear frequency modulation continuous wave speed and distance measuring laser three-dimensional imaging method, the image processor acquires the detection intensity of each target sampling point through the preset sampling range and sampling interval of the target by coherent detection, reversely deduces the gray information of the detected target through the relation between the intensity and the target detection to obtain the gray image of the target point, measures the round-trip flight time of laser frequency modulation pulses at the target sampling points and the two-dimensional space position corresponding to the detection pixel to obtain the three-dimensional distance image of the target point, reconstructs the distance-intensity three-dimensional point cloud image of the target through the gray image and the three-dimensional distance image of the target point, and finally displays the distance-intensity three-dimensional point cloud image through the image display.
According to the scanning-free linear frequency modulation continuous wave speed and distance measuring laser three-dimensional imaging method, the image processor acquires the speed and direction of each sampling point of the target by coherent detection through the preset sampling range and sampling interval of the target, and a distance-speed three-dimensional point cloud image of the target is reconstructed by combining the three-dimensional distance image of the target point.
The device for realizing the non-scanning linear frequency modulation continuous wave speed and distance measuring laser three-dimensional imaging method is characterized in that: the linear frequency modulation continuous laser light source is connected with a space optical circulator through a beam splitter;
the output end of the space optical circulator is connected with an optical telescope; the space optical circulator and the beam splitter are connected with a space optical bridge together; the space optical bridge is connected with a double-channel focal plane reading circuit through a double-channel focal plane array balance detector, the double-channel focal plane reading circuit is sequentially connected with a band-pass filter and an analog-to-digital converter, the analog-to-digital converter is connected with an image processor through a field programmable gate array, and the image processor is further connected with an image display.
In the foregoing apparatus, a laser amplifier is further disposed between the beam splitter and the spatial optical circulator.
Compared with the prior art, the output light beam generated by the linear frequency modulation continuous laser light source is divided into the local oscillation light beam and the signal light beam by the beam splitter; the method comprises the steps of transmitting a signal beam to a target and receiving an echo beam of the target, carrying out coherent light mixing on the echo beam and a local oscillator beam through a space optical bridge, carrying out parallel balanced receiving by using a dual-channel focal plane array balanced detector to obtain an intermediate frequency signal containing target distance and speed information, reading the intermediate frequency signal by using a dual-channel focal plane reading circuit, carrying out filtering processing and sampling processing to obtain sampling data, carrying out real-time parallel fast Fourier transform and cross-spectrum processing on the sampling data by using a field programmable gate array to realize parallel synchronous measurement of the target distance and speed, and respectively constructing a distance-intensity three-dimensional point cloud image and a distance-speed three-dimensional point cloud image by combining with an image processor. Therefore, the method can be used for scanning-free imaging of the remote target by combining the coherent detection technology with the array detection technology, can obtain a distance-intensity image containing the gray scale information of the remote target and the spatial three-dimensional geometric position relation, and can also obtain the size and the direction of the radial speed of the relative motion of the radar platform and the target; in addition, the invention realizes the coaxial receiving and transmitting through the space optical circulator and the optical telescope, is beneficial to the integration miniaturization and reduces the complexity of the system; the invention can achieve the purpose of three-dimensional imaging without a complex scanning mechanism, has the advantages of high resolution, high precision and undistorted imaging on the premise of small volume and simple structure, and has lower cost compared with the existing scanless three-dimensional imaging technology, thereby having good development prospect.
Drawings
Fig. 1 is a schematic structural view of the present invention.
Fig. 2 is a schematic diagram of a symmetrical triangular linear modulation waveform according to the present invention.
Fig. 3 is a schematic diagram of the coordinate system of the radar-target of the present invention.
Fig. 4 is a schematic diagram of a 2 x 490 ° spatial optical bridge of the present invention.
FIG. 5 is a schematic diagram of a dual channel focal plane array balanced detector of the present invention.
FIG. 6 shows the distance-intensity three-dimensional point cloud image and the distance-velocity three-dimensional point cloud image of the moving body measured at a distance of 20 meters in the example.
The labels in the figures are: 1. a linear frequency modulated continuous laser light source; 2. a beam splitter; 3. a laser amplifier; 4. a spatial optical circulator; 5. an optical telescope; 6. a spatial optical bridge; 7. a dual-channel focal plane array balance detector; 8. a dual-channel focal plane readout circuit; 9. a band-pass filter; 10. an analog-to-digital converter; 11. a field programmable gate array; 12. an image processor; 13. an image display; 171. a polarization beam splitter prism; 172. a total reflection mirror; 173. a first half wave plate; 174. a second half-wave plate; 175. a third half-wave plate; 176. a quarter wave plate; 177. a first polarization beam splitting combination prism; 178. and the second polarization beam splitting and combining prism.
Detailed Description
The invention is further illustrated by the following figures and examples, which are not to be construed as limiting the invention.
Example (b): the device of the laser three-dimensional imaging method for speed measurement and distance measurement of the scanless linear frequency modulation continuous wave comprises a linear frequency modulation continuous laser light source 1, wherein the laser light source 1 adopts a 1550nm single-mode narrow-line-width continuous optical fiber laser which is safe for human eyes, the line width of the laser is 10kHz, the output power is 20mW, the output of an optical fiber is provided with isolation protection, a frequency modulation signal generated by a frequency modulation signal generator and a fundamental frequency signal generated by a fundamental frequency signal generator are mixed to obtain a mixing signal, the mixing signal is used as a driving signal of an optical fiber phase modulator to drive the optical fiber phase modulator to generate a frequency modulation laser signal, harmonic waves are inhibited through an optical filter, the frequency modulation laser signal of a required order is reserved, the frequency modulation bandwidth is 5GHz, the frequency modulation rate is 5THz/s, symmetrical triangular wave linear modulation is adopted, the frequency of the modulation signal changes in a symmetrical, the first half part is positive frequency modulation, the second half part is negative frequency modulation, fig. 2 shows a symmetrical triangular linear modulation waveform schematic diagram, and the laser light field emission is represented as:
Figure DEST_PATH_IMAGE185
，
wherein the content of the first and second substances,
Figure DEST_PATH_IMAGE186
is the time of day or the like,
Figure DEST_PATH_IMAGE187
is the amplitude of the wave, and,
Figure DEST_PATH_IMAGE188
in order to have a frequency-modulated period,in order to frequency-modulate the initial frequency,
Figure DEST_PATH_IMAGE190
in order to be able to modulate the frequency rate,in order to adjust the bandwidth of the frequency band,
Figure DEST_PATH_IMAGE192
is as follows
Figure DEST_PATH_IMAGE193
The initial phase of the rising segment of the laser frequency modulation pulse,
Figure DEST_PATH_IMAGE194
is as follows
Figure 777230DEST_PATH_IMAGE193
Initial phase of descending section of frequency modulation pulse of each emission laser;
the output laser firstly passes through an online polarizing/controller, the polarization extinction ratio is ensured to be larger than 25dB, and the polarization direction can be controlled to rotate; then the polarized light passes through a 1 × 2 fiber polarization beam splitter 2, and the polarization states of the outgoing two paths of light are horizontal polarization and vertical polarization respectively. The emergent polarization direction is changed by adjusting the online polarizing/controller, so that the light intensity of two paths output by the 1 multiplied by 2 optical fiber polarization beam splitter is ensured to be 1: 99. According to the invention, a horizontal polarized light branch is used as a signal light beam, and a vertical polarized light branch is used as a local oscillator light beam;
local oscillator beam as time delay
Figure DEST_PATH_IMAGE195
The optical field is represented as:
Figure DEST_PATH_IMAGE196
，
wherein the content of the first and second substances,
Figure DEST_PATH_IMAGE197
is the amplitude of the local oscillator beam,
Figure DEST_PATH_IMAGE198
is the noise phase of the local oscillator beam;
the signal light beam is firstly amplified by an erbium-doped fiber amplifier, the transmitting power is 5W, the signal light beam enters a space optical circulator 4 through an optical fiber collimation transmitter, the optical circulator 4 consists of a polarization beam splitter prism, a Faraday optical rotator and a half-wave plate, the Faraday optical rotator rotates the polarization state of horizontal polarized light by 45 degrees, the slow axis of the half-wave plate and the incident polarization state form 22.5 degrees, the polarization state of the emitted light can be rotated by 90 degrees, and the polarization states of the received light are kept unchanged. The horizontally polarized emitted light passes through a faraday rotator and a half-wave plate, and the polarization state is changed into vertical polarization. Then the light is transmitted out through a transmitting/receiving optical telescope 5 with the power of 10 times to irradiate the target. The target echo beam received by the transmitting/receiving optical telescope 5 is the first on the target plane
Figure DEST_PATH_IMAGE199
A scattering target
Figure DEST_PATH_IMAGE200
Time delay of
Figure DEST_PATH_IMAGE201
The linear frequency modulated signal of (a);
as shown in fig. 3, in the radar-target coordinate system
Figure DEST_PATH_IMAGE202
In (1),
Figure DEST_PATH_IMAGE203
has the coordinates of
Figure DEST_PATH_IMAGE204
，
The distance between the radar and the target
Figure DEST_PATH_IMAGE205
Expressed as:
，
for the purpose of remote detection of the object,
Figure DEST_PATH_IMAGE207
，
Figure DEST_PATH_IMAGE208
and thus;
target
Figure DEST_PATH_IMAGE210
Time delay of echo light beamExpressed as:
Figure 577751DEST_PATH_IMAGE057
，
wherein the content of the first and second substances,
Figure 94183DEST_PATH_IMAGE059
it is the speed of light that is,
Figure 810466DEST_PATH_IMAGE061
is a radar platform and target
Figure DEST_PATH_IMAGE211
The radial speed of the relative movement is,
Figure 146769DEST_PATH_IMAGE065
is a radar platform and target
Figure 606701DEST_PATH_IMAGE067
The doppler shift caused by the radial velocity of the relative motion,
by the resulting time delay
Figure 977639DEST_PATH_IMAGE069
On the target plane
Figure 628938DEST_PATH_IMAGE071
A scattering target
Figure 452538DEST_PATH_IMAGE073
The light field of the echo light beam of (a) is expressed as:
Figure DEST_PATH_IMAGE212
，
wherein the content of the first and second substances,
Figure DEST_PATH_IMAGE213
is the amplitude of the echo light beam,
Figure 981739DEST_PATH_IMAGE079
is the noise phase of the echo beam.
On the target plane
Figure 82550DEST_PATH_IMAGE081
A scattering target
Figure DEST_PATH_IMAGE214
After the echo light beam and the local oscillator light beam are combined by the 2X 490-degree space optical bridge 6The light field is represented as:
Figure DEST_PATH_IMAGE215
，
the spatial optical bridge structure is shown in fig. 4, a free space structure 2 × 490-degree optical bridge is adopted, the light transmission aperture of the 2 × 490-degree optical bridge is 32mm × 32mm, the spatial optical bridge consists of a polarization beam splitter 171, a holophote 172, a first half-wave plate 173, a second half-wave plate 174, a third half-wave plate 175, a quarter-wave plate 176, a first polarization beam splitting combination prism 177 and a second polarization beam splitting combination prism 178, an echo light beam and a local oscillator light beam are orthogonally coherently received by the 2 × 490-degree spatial optical bridge, and four outputs after frequency mixing of the 2 × 490-degree spatial optical bridge are respectively:
Figure DEST_PATH_IMAGE216
，
Figure DEST_PATH_IMAGE217
，
wherein the content of the first and second substances,
Figure 904750DEST_PATH_IMAGE091
is a mixing of the noise phases and is,
Figure 356592DEST_PATH_IMAGE093
is a direct current quantity related to the echo beam;
Figure DEST_PATH_IMAGE218
is a direct current quantity related to the local oscillator beam,is the optical heterodyne receiver directivity function;
thus, from the first on the target plane
Figure DEST_PATH_IMAGE221
A scattering target
Figure DEST_PATH_IMAGE223
The signals are divided into in-phase signals and orthogonal signals with orthogonal characteristics, as shown in fig. 5, the in-phase signals and the orthogonal signals with orthogonal characteristics output by the space optical bridge are respectively processed by D in a 2 × M × N unit dual-channel focal plane array balanced detector 7n-And Dn+Receiving to obtain the target plane M multiplied by N points containing the targetIntermediate frequency signals of distance and velocity information; the total number of pixels of the 2 XMXN unit dual-channel focal plane array balanced detector is 2X 256, the number of pixels of each channel is 256X 256, each pixel is an InGaAs device, the size of each pixel is 0.1mm, the interval is 0.125mm, the duty ratio is 0.8, the size of each channel photosurface is 32mm X32 mm, two photodiodes with completely similar characteristics are adopted at corresponding positions of the two channel photosurfaces for photoelectric conversion, a differential amplifier is used at the rear end, differential signals are amplified after the two channels are differentiated, and common-mode noise is inhibited; the intermediate frequency signal is an in-phase signal and an orthogonal signal output by the 2 × mxn unit dual-channel focal plane array balanced detector 7, and the signals are respectively:
Figure DEST_PATH_IMAGE224
，
Figure DEST_PATH_IMAGE225
，
wherein
Figure 346599DEST_PATH_IMAGE103
Photoelectric detection unit for receiving in-phase signal channel in dual-channel focal plane array balanced detector
Figure 231378DEST_PATH_IMAGE105
The response rate of (a) to (b),
Figure 904936DEST_PATH_IMAGE107
is a dual-channel focal plane array balance probePhotoelectric detection unit for receiving orthogonal signal channel in detector
Figure 634995DEST_PATH_IMAGE109
The response rate of (a) to (b),
Figure 444819DEST_PATH_IMAGE111
and
Figure DEST_PATH_IMAGE226
noise phases of the in-phase signal and the quadrature signal, respectively;
simplifying the amplitude of the in-phase and quadrature signals (i.e. reducing the amplitude of the quadrature signal
Figure DEST_PATH_IMAGE228
、
Figure DEST_PATH_IMAGE230
Are used separately
Figure DEST_PATH_IMAGE232
And
Figure DEST_PATH_IMAGE234
instead):
Figure DEST_PATH_IMAGE235
,
then the in-phase signal and the quadrature signal output by the dual-channel focal plane array balanced detector 7 are simplified as follows:
，
Figure 527534DEST_PATH_IMAGE119
；
the outputs of the in-phase signal channel and the orthogonal signal channel photoelectric detection units are respectively read out intermediate frequency signals through a dual-channel focal plane readout circuit, and after the intermediate frequency signals are subjected to band-pass filter filtering processing, analog-to-digital conversion is completed through a high-speed analog-to-digital converter, and then the signals are collected by a field programmable gate array, and Doppler frequency shift measurement and distance measurement are respectively performed:
firstly, fast fourier transform is respectively performed on two channels of data, and the in-phase signal channel fourier transform is expressed as:
Figure DEST_PATH_IMAGE236
，
the orthogonal signal path fourier transform is represented as:
Figure DEST_PATH_IMAGE237
，
performing cross-spectrum processing on the two channels:
Figure DEST_PATH_IMAGE238
，
finally, only the imaginary part is taken to obtain
Figure DEST_PATH_IMAGE239
，
Extracting the peak position and the positive and negative of the frequency spectrum by a gravity center method to respectively obtain frequency values in the positive frequency modulation process and the negative frequency modulation process
Figure 936650DEST_PATH_IMAGE129
：
，
From the above formula, one can obtain:
Figure 99516DEST_PATH_IMAGE133
，
wherein
Figure DEST_PATH_IMAGE242
Is the frequency value in the forward frequency modulation process,
Figure DEST_PATH_IMAGE244
the frequency value in the negative frequency modulation process; because the Doppler frequency shift is in direct proportion to the relative movement speed of the radar platform and the target, the positive and negative Doppler frequency shifts are related to the direction of the radial speed of the relative movement, the positive frequency shift represents that the radar platform and the target move in the opposite direction, and the negative frequency shift represents that the radar platform and the target move in the opposite direction;
therefore, the radar platform and the target can be obtained by Doppler frequency shiftThe magnitude and direction of the radial velocity of the relative motion are expressed as
Figure DEST_PATH_IMAGE246
，
Wherein
Figure 201464DEST_PATH_IMAGE142
Is the output beam wavelength;
obtaining the second on the target plane from the above formula
Figure DEST_PATH_IMAGE247
A scattering target
Figure 318456DEST_PATH_IMAGE146
Is a distance of
Figure 655896DEST_PATH_IMAGE148
：
Figure DEST_PATH_IMAGE248
。
On the target plane
Figure 735585DEST_PATH_IMAGE152
A scattering target
Figure 477276DEST_PATH_IMAGE154
The return beam deflection angle ofThen optical heterodyne receives the directional functionComprises the following steps:
Figure DEST_PATH_IMAGE250
，
wherein the content of the first and second substances,
Figure 753854DEST_PATH_IMAGE162
in the form of a first order bezier function,
Figure 658356DEST_PATH_IMAGE164
is the magnification factor of the optical telescope,
Figure 695582DEST_PATH_IMAGE166
is the diameter of the photodetecting unit, so the reception field angle is expressed as:
Figure 646221DEST_PATH_IMAGE168
，
m multiplied by N is the number of pixels of a single channel of the dual-channel focal plane array balanced detector; m is 256 and N is 256;
the receiving field angle in the embodiment is 55.5 degrees × 55.5 degrees;
the range resolution is expressed as:
，
wherein the content of the first and second substances,
Figure 964944DEST_PATH_IMAGE172
it is the speed of light that is,
Figure 989532DEST_PATH_IMAGE174
is a linear frequency modulation bandwidth;
the distance resolution in this example is 3 cm;
the velocity resolution is expressed as:
Figure 463239DEST_PATH_IMAGE176
，
wherein the content of the first and second substances,
Figure 307698DEST_PATH_IMAGE178
in order to have a frequency-modulated period,in order to frequency-modulate the initial frequency,
Figure 466464DEST_PATH_IMAGE182
in order to frequency-modulate the initial wavelength,
Figure 720859DEST_PATH_IMAGE184
is the frequency modulation rate.
The velocity resolution in this example is 0.775 mm/s.
After parallel synchronous measurement of the target distance and speed, a distance-intensity three-dimensional point cloud image and a distance-speed three-dimensional point cloud image are respectively constructed by combining an image processor, on one hand, the image processor acquires the detection intensity of each target sampling point by utilizing coherent detection through a pre-designed sampling range and sampling interval of a detected target, on the other hand, the gray information of the detected target is reversely deduced through the relation between the intensity and the target detection, and meanwhile, the round-trip flight time of laser frequency modulation pulses at the sampling points and the two-dimensional space position corresponding to a detection pixel are measured, and the three-dimensional distance image of the target point is obtained; reconstructing a distance-intensity three-dimensional point cloud image of the target by the gray level image and the distance image of the target point, wherein different point cloud colors represent different distances and are displayed by an image display; on the other hand, the speed and the direction of each target sampling point are obtained through the coherent detection, the distance image of the target point is combined, the distance-speed three-dimensional point cloud image of the target is reconstructed, the color of the point cloud only adopts red and blue, the red represents that the radar platform moves opposite to the target, the blue represents that the radar platform moves back to the target, and the depth of the color represents the speed, and the speed is displayed through an image display. Fig. 6 shows a distance-intensity three-dimensional point cloud image and a distance-velocity three-dimensional point cloud image of a moving body measured at a distance of 20 meters in this embodiment, and it can be seen from fig. 6 that the three-dimensional imaging image of the present invention has the characteristics of high resolution and high precision, and the dynamic target image has no distortion. The invention can not only obtain the distance-intensity image containing the gray scale information of the remote target and the spatial three-dimensional geometric position relation, but also obtain the size and the direction of the radial speed of the relative motion of the radar platform and the target, and has the advantages of small volume, light weight, high resolution, high precision, undistorted three-dimensional imaging of the dynamic target and the like.

Claims (9)

1. The laser three-dimensional imaging method for speed and distance measurement of the non-scanning linear frequency modulation continuous wave is characterized by comprising the following steps: an output light beam generated by a linear frequency modulation continuous laser light source of the radar platform is divided into a local oscillator light beam and a signal light beam by a beam splitter; the method comprises the steps of transmitting a signal beam to a target and receiving an echo beam of the target, carrying out coherent light mixing on the echo beam and a local oscillator beam through a space optical bridge, carrying out parallel balanced receiving by using a dual-channel focal plane array balanced detector to obtain an intermediate frequency signal containing target distance and speed information, reading the intermediate frequency signal by using a dual-channel focal plane reading circuit, carrying out filtering processing and sampling processing on the intermediate frequency signal to obtain sampling data, carrying out real-time parallel fast Fourier transform and cross-spectrum processing on the sampling data by using a field programmable gate array to realize parallel synchronous measurement of target distance and speed, and finally combining an image processor to respectively construct a distance-intensity three-dimensional point cloud image and a distance-speed three-dimensional point cloud image.
2. The laser three-dimensional imaging method for speed and distance measurement of the scanless chirp continuous wave according to claim 1, wherein: the synchronous measurement of the target distance and the target speed is realized, specifically, Fourier transformation is respectively carried out on an in-phase signal and an orthogonal signal output by a dual-channel focal plane array balanced detector, then cross-spectrum processing is carried out to obtain a Doppler frequency spectrum, then an imaginary part of the Doppler frequency spectrum is obtained, the position and the positive and negative of a peak value in the Doppler frequency spectrum are extracted by using a gravity center method to obtain Doppler frequency shift generated by relative motion of a radar platform and a target, and then the size and the direction of the radial speed of the relative motion of the radar platform and the target distance are obtained by the Doppler frequency shift.
3. The laser three-dimensional imaging method for speed and distance measurement of the scanless chirp continuous wave according to claim 1, wherein: the output light beam generated by the linear frequency modulation continuous laser light source is continuous coherent laser with linearly modulated frequency, symmetrical triangular wave linear modulation is adopted, the frequency of a modulation signal changes in a symmetrical triangular mode along with time, in a period, the front half part is positive frequency modulation, the rear half part is negative frequency modulation, and the light field is expressed as follows:
Figure DEST_PATH_IMAGE001
，
wherein the content of the first and second substances,
Figure 805822DEST_PATH_IMAGE002
is the time of day or the like,
Figure DEST_PATH_IMAGE003
is the amplitude of the wave, and,
Figure 873135DEST_PATH_IMAGE004
in order to have a frequency-modulated period,in order to frequency-modulate the initial frequency,in order to be able to modulate the frequency rate,
Figure DEST_PATH_IMAGE007
in order to adjust the bandwidth of the frequency band,is as follows
Figure DEST_PATH_IMAGE009
The initial phase of the rising segment of the laser frequency modulation pulse,
Figure 88587DEST_PATH_IMAGE010
is as follows
Figure DEST_PATH_IMAGE011
Initial phase of descending section of frequency modulation pulse of each emission laser;
split by a 1X 2 beam splitter, a small part of energy is used as a local oscillation light beam which is time delay
Figure 84225DEST_PATH_IMAGE012
The optical field is represented as:
Figure DEST_PATH_IMAGE013
，
wherein the content of the first and second substances,
Figure 690787DEST_PATH_IMAGE014
is the amplitude of the local oscillator beam,
Figure DEST_PATH_IMAGE015
is the noise phase of the local oscillator beam;
most energy is used as a signal beam, the signal beam is transmitted to a target through a space optical circulator and an optical telescope, and an echo beam of the target is received by the optical telescope; after passing through the space optical circulator, the echo beam is on the target planeA scattering target
Figure DEST_PATH_IMAGE017
Time delay of
Figure 570240DEST_PATH_IMAGE018
The linear frequency modulated signal of (a);
in the radar-target coordinate system
Figure DEST_PATH_IMAGE019
In (1),
Figure 244935DEST_PATH_IMAGE020
has the coordinates of
Figure 33899DEST_PATH_IMAGE021
，
The radar and the target
Figure 870268DEST_PATH_IMAGE017
Distance between each other
Figure DEST_PATH_IMAGE022
Expressed as:
Figure 783998DEST_PATH_IMAGE023
，
for the purpose of remote detection of the object,
Figure DEST_PATH_IMAGE024
，
Figure 495339DEST_PATH_IMAGE025
thus, therefore, it is
Figure DEST_PATH_IMAGE026
；
Target
Figure 935548DEST_PATH_IMAGE027
Time delay of echo light beam
Figure DEST_PATH_IMAGE028
Expressed as:
Figure 208398DEST_PATH_IMAGE029
，
wherein the content of the first and second substances,
Figure DEST_PATH_IMAGE030
it is the speed of light that is,
Figure 609423DEST_PATH_IMAGE031
is a radar platform and targetThe radial speed of the relative movement is,is a radar platform and target
Figure DEST_PATH_IMAGE034
The doppler shift caused by the radial velocity of the relative motion,
by the resulting time delay
Figure 28958DEST_PATH_IMAGE035
On the target plane
Figure DEST_PATH_IMAGE036
A scattering targetThe light field of the echo light beam of (a) is expressed as:
Figure DEST_PATH_IMAGE038
，
wherein the content of the first and second substances,
Figure 485664DEST_PATH_IMAGE039
is the amplitude of the echo light beam,is the noise phase of the echo beam.
4. The laser three-dimensional imaging method for speed and distance measurement of the scanless chirp continuous wave according to claim 3, wherein: on the target plane
Figure 305852DEST_PATH_IMAGE041
A scattering target
Figure DEST_PATH_IMAGE042
The optical field after the echo light beam and the local oscillator light beam are combined by the 2 × 490-degree spatial optical bridge is represented as:
，
the four outputs after being mixed by the 2 × 490-degree spatial optical bridge are respectively:
Figure DEST_PATH_IMAGE044
，
Figure 443627DEST_PATH_IMAGE045
，
wherein the content of the first and second substances,
Figure DEST_PATH_IMAGE046
is a mixing of the noise phases and is,
Figure 819245DEST_PATH_IMAGE047
is a direct current quantity related to the echo beam;is a direct current quantity related to the local oscillator beam,
Figure 911966DEST_PATH_IMAGE049
is the optical heterodyne receiver directivity function;
in-phase signals and orthogonal signals with orthogonal characteristics output by the space optical bridge are respectively received by the 2 XMXN unit dual-channel focal plane array balanced detector to obtain a target containing M XN points of a target planeIntermediate frequency signals of distance and velocity information; the intermediate frequency signal is an in-phase signal and a quadrature signal output by two channels of the 2 XMXN unit dual-channel focal plane array balanced detector, and the signals are respectively:
Figure DEST_PATH_IMAGE050
，
Figure 701248DEST_PATH_IMAGE051
，
wherein
Figure DEST_PATH_IMAGE052
Photoelectric detection unit for receiving in-phase signal channel in dual-channel focal plane array balanced detector
Figure 734800DEST_PATH_IMAGE053
The response rate of (a) to (b),
Figure DEST_PATH_IMAGE054
photoelectric detection unit for receiving orthogonal signal channel in dual-channel focal plane array balanced detectorThe response rate of (a) to (b),
Figure DEST_PATH_IMAGE056
and
Figure 755026DEST_PATH_IMAGE057
noise phases of the in-phase signal and the quadrature signal, respectively;
the amplitudes of the in-phase signal and the quadrature signal are simplified:
Figure DEST_PATH_IMAGE058
,
the inphase signal and the orthogonal signal output by the double-channel focal plane array balanced detector are simplified as follows:
Figure 711481DEST_PATH_IMAGE059
，
Figure DEST_PATH_IMAGE060
；
the outputs of the in-phase signal channel and the orthogonal signal channel photoelectric detection units are respectively read out intermediate frequency signals through a dual-channel focal plane readout circuit, and after the intermediate frequency signals are subjected to band-pass filter filtering processing, analog-to-digital conversion is completed through a high-speed analog-to-digital converter, and then the signals are collected by a field programmable gate array, and Doppler frequency shift measurement and distance measurement are respectively performed:
specifically, firstly, the two channels of data are respectively subjected to fast fourier transform, and the in-phase signal channel fourier transform is expressed as:
Figure 560226DEST_PATH_IMAGE061
，
the orthogonal signal path fourier transform is represented as:
Figure DEST_PATH_IMAGE062
，
performing cross-spectrum processing on the two channels:
Figure 260329DEST_PATH_IMAGE063
，
finally, only the imaginary part is taken to obtain
Figure DEST_PATH_IMAGE064
，
Extracting the peak position and the positive and negative of the frequency spectrum by a gravity center method to respectively obtain frequency values in the positive frequency modulation process and the negative frequency modulation process
Figure 114015DEST_PATH_IMAGE065
：
Figure DEST_PATH_IMAGE066
，
From the above formula, one can obtain:
Figure 241371DEST_PATH_IMAGE067
，
in the above formula, the first and second carbon atoms are,is the frequency value in the forward frequency modulation process,
Figure 937932DEST_PATH_IMAGE069
is the frequency value in the negative frequency modulation process; because the Doppler frequency shift is in direct proportion to the radial speed of the relative motion of the radar platform and the target, the positive and negative Doppler frequency shifts are related to the direction of the radial speed of the relative motion of the radar platform and the target, the positive frequency shift represents that the radar platform and the target move in the opposite direction, and the negative frequency shift represents that the radar platform and the target move in the opposite direction;
thus obtaining the radar platform and the target from the Doppler frequency shift
Figure DEST_PATH_IMAGE070
The magnitude and direction of the radial velocity of the relative motion are expressed as
Figure 940260DEST_PATH_IMAGE071
，
Wherein
Figure DEST_PATH_IMAGE072
Is the output beam wavelength;
obtaining the second on the target plane from the above formula
Figure 914033DEST_PATH_IMAGE073
A scattering target
Figure DEST_PATH_IMAGE074
Is a distance of
Figure 946711DEST_PATH_IMAGE075
：
Figure DEST_PATH_IMAGE076
。
5. The scanless chirp continuous wave velocimetry (FMCW) laser three-dimensional imaging method according to claim 4, wherein:
on the target plane
Figure 271513DEST_PATH_IMAGE077
A scattering targetThe return beam deflection angle of
Figure 811953DEST_PATH_IMAGE079
Then optical heterodyne receives the directional function
Figure DEST_PATH_IMAGE080
Comprises the following steps:
，
wherein the content of the first and second substances,
Figure DEST_PATH_IMAGE082
in the form of a first order bezier function,
Figure 234024DEST_PATH_IMAGE083
is the magnification factor of the optical telescope,
Figure DEST_PATH_IMAGE084
is the diameter of the photodetecting unit, so the reception field angle is expressed as:
Figure 780543DEST_PATH_IMAGE085
m multiplied by N is the number of pixels of a single channel of the dual-channel focal plane array balanced detector;
the range resolution is expressed as:
Figure DEST_PATH_IMAGE086
，
wherein the content of the first and second substances,
Figure 626140DEST_PATH_IMAGE087
it is the speed of light that is,
Figure DEST_PATH_IMAGE088
is a linear frequency modulation bandwidth;
the velocity resolution is expressed as:
Figure 807460DEST_PATH_IMAGE089
，
wherein the content of the first and second substances,
Figure DEST_PATH_IMAGE090
in order to have a frequency-modulated period,
Figure 713099DEST_PATH_IMAGE091
in order to frequency-modulate the initial frequency,in order to frequency-modulate the initial wavelength,
Figure 481335DEST_PATH_IMAGE093
is the frequency modulation rate.
6. The laser three-dimensional imaging method for speed and distance measurement of the scanless chirp continuous wave according to claim 1, wherein: the image processor acquires detection intensity of each target sampling point through preset sampling range and sampling interval of the target by coherent detection, reversely deduces gray information of the target to be detected through the relation between the intensity and the target detection to obtain a gray image of the target point, measures the round-trip flight time of laser frequency modulation pulse at the target sampling point and a two-dimensional space position corresponding to a detection pixel to obtain a three-dimensional distance image of the target point, reconstructs a distance-point cloud intensity three-dimensional point cloud image of the target by the gray image and the three-dimensional distance image of the target point, different colors of point cloud represent different distances, and finally displays the distance image through an image display.
7. The scanless chirp continuous wave velocimetry (FMCW) laser three-dimensional imaging method according to claim 6, wherein: the image processor acquires the speed and the direction of each target sampling point by using coherent detection through a preset sampling range and a preset sampling interval of the target, and reconstructs a distance-speed three-dimensional point cloud image of the target by combining a three-dimensional distance image of the target point.
8. The device for realizing the laser three-dimensional imaging method of speed measurement and distance measurement of the non-scanning linear frequency modulation continuous waves according to any one of claims 1 to 7 is characterized in that: the device comprises a linear frequency modulation continuous laser light source (1), wherein the linear frequency modulation continuous laser light source (1) is connected with a space optical circulator (4) through a beam splitter (2);
the output end of the space optical circulator (4) is connected with an optical telescope (5); the space optical circulator (4) and the beam splitter (2) are connected with a space optical bridge (6) together; the space optical bridge (6) is connected with a double-channel focal plane reading circuit (8) through a double-channel focal plane array balance detector (7), the double-channel focal plane reading circuit (8) is sequentially connected with a band-pass filter (9) and an analog-to-digital converter (10), the analog-to-digital converter (10) is connected with an image processor (12) through a field programmable gate array (11), and the image processor (12) is further connected with an image display (13).
9. The apparatus of claim 8, wherein: and a laser amplifier (3) is also arranged between the beam splitter (2) and the space optical circulator (4).
CN202010016103.2A 2020-01-08 2020-01-08 Non-scanning linear frequency modulation continuous wave speed and distance measuring laser three-dimensional imaging method and device Active CN110806586B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202010016103.2A CN110806586B (en) 2020-01-08 2020-01-08 Non-scanning linear frequency modulation continuous wave speed and distance measuring laser three-dimensional imaging method and device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202010016103.2A CN110806586B (en) 2020-01-08 2020-01-08 Non-scanning linear frequency modulation continuous wave speed and distance measuring laser three-dimensional imaging method and device

Publications (2)

Publication Number Publication Date
CN110806586A true CN110806586A (en) 2020-02-18
CN110806586B CN110806586B (en) 2020-04-14

Family

ID=69493303

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202010016103.2A Active CN110806586B (en) 2020-01-08 2020-01-08 Non-scanning linear frequency modulation continuous wave speed and distance measuring laser three-dimensional imaging method and device

Country Status (1)

Country Link
CN (1) CN110806586B (en)

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111308497A (en) * 2020-03-06 2020-06-19 深圳市方腾网络技术有限公司 3D laser radar and laser radar implementation method
CN111337902A (en) * 2020-04-29 2020-06-26 杭州爱莱达科技有限公司 Multi-channel high-repetition-frequency large-dynamic-range distance and speed measuring laser radar method and device
CN111473856A (en) * 2020-04-01 2020-07-31 中国科学院微电子研究所 Bridge deck three-dimensional vibration detection device and method based on laser and storage medium
CN111650601A (en) * 2020-06-01 2020-09-11 杭州爱莱达科技有限公司 High-resolution 3D imaging method and device for vehicle-mounted coherent laser radar
CN111896973A (en) * 2020-07-16 2020-11-06 武汉大学 Ultra-long-distance target three-dimensional motion trajectory prediction method based on active and passive fusion
CN112230238A (en) * 2020-12-09 2021-01-15 武汉光谷航天三江激光产业技术研究院有限公司 Laser intensity modulation distance and speed measuring method and system, terminal device and storage medium
CN112731396A (en) * 2020-12-22 2021-04-30 华中科技大学 Synthetic aperture radar millimeter wave imaging method and system based on in-phase signal measurement
CN112965078A (en) * 2021-02-04 2021-06-15 郜键 AMCW long-distance laser imaging device based on MSM detection
CN113109834A (en) * 2021-04-16 2021-07-13 中国人民解放军国防科技大学 High-energy and high-precision underwater three-dimensional imaging laser radar system and method
CN113702992A (en) * 2020-05-23 2021-11-26 北醒（北京）光子科技有限公司 Laser detection device
CN113835074A (en) * 2021-08-04 2021-12-24 南京常格科技发展有限公司 People flow dynamic monitoring method based on millimeter wave radar
CN114938662A (en) * 2021-10-13 2022-08-23 深圳市速腾聚创科技有限公司 Laser radar and control method of laser radar
CN115210603A (en) * 2021-10-20 2022-10-18 深圳市速腾聚创科技有限公司 Laser radar and laser radar control method
CN115508859A (en) * 2022-11-11 2022-12-23 武汉光谷航天三江激光产业技术研究院有限公司 Laser three-dimensional imaging method and system based on single balanced detector
WO2023029393A1 (en) * 2021-08-31 2023-03-09 上海禾赛科技有限公司 Balanced detector and frequency modulation continuous wave radar
CN115902920A (en) * 2023-02-23 2023-04-04 中国人民解放军国防科技大学 Coherent and incoherent laser cooperative detection method and system for aerial moving object
CN116930995A (en) * 2023-09-19 2023-10-24 天津大学四川创新研究院 System and method for measuring speed and distance of high-speed target of frequency modulation continuous wave laser
CN117872322A (en) * 2024-03-12 2024-04-12 北醒（北京）光子科技有限公司 Frequency modulation continuous wave laser radar and radar navigation system

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060227316A1 (en) * 2005-04-06 2006-10-12 Phillip Gatt Three-dimensional imaging device
CN201032490Y (en) * 2007-03-29 2008-03-05 中国科学院上海光学精密机械研究所 Coherent laser ranger capable of obtaining target location information
CN101236253A (en) * 2008-03-07 2008-08-06 中国科学院上海光学精密机械研究所 High precision speed-measuring distance-measuring radar system and method
CN106226778A (en) * 2016-08-23 2016-12-14 成都信息工程大学 A kind of coherent lidar system of high resolution measurement remote object
CN105372670B (en) * 2015-09-22 2018-08-14 中国科学院上海技术物理研究所 Coherent homodyne Doppler speed measuring laser radar system based on optics quadrature demodulation
WO2019014177A1 (en) * 2017-07-10 2019-01-17 Blackmore Sensors and Analytics Inc. Method and system for time separated quadrature detection of doppler effects in optical range measurements
WO2019070751A1 (en) * 2017-10-02 2019-04-11 Bridger Photonics, Inc. Processing temporal segments of laser chirps and examples of use in fmcw lidar methods and apparatuses

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060227316A1 (en) * 2005-04-06 2006-10-12 Phillip Gatt Three-dimensional imaging device
CN201032490Y (en) * 2007-03-29 2008-03-05 中国科学院上海光学精密机械研究所 Coherent laser ranger capable of obtaining target location information
CN101236253A (en) * 2008-03-07 2008-08-06 中国科学院上海光学精密机械研究所 High precision speed-measuring distance-measuring radar system and method
CN105372670B (en) * 2015-09-22 2018-08-14 中国科学院上海技术物理研究所 Coherent homodyne Doppler speed measuring laser radar system based on optics quadrature demodulation
CN106226778A (en) * 2016-08-23 2016-12-14 成都信息工程大学 A kind of coherent lidar system of high resolution measurement remote object
WO2019014177A1 (en) * 2017-07-10 2019-01-17 Blackmore Sensors and Analytics Inc. Method and system for time separated quadrature detection of doppler effects in optical range measurements
WO2019070751A1 (en) * 2017-10-02 2019-04-11 Bridger Photonics, Inc. Processing temporal segments of laser chirps and examples of use in fmcw lidar methods and apparatuses

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
卢炤宇: "频率调制连续波激光雷达技术基础与研究进展", 《光电工程》 *

Cited By (27)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111308497A (en) * 2020-03-06 2020-06-19 深圳市方腾网络技术有限公司 3D laser radar and laser radar implementation method
CN111473856A (en) * 2020-04-01 2020-07-31 中国科学院微电子研究所 Bridge deck three-dimensional vibration detection device and method based on laser and storage medium
CN111337902A (en) * 2020-04-29 2020-06-26 杭州爱莱达科技有限公司 Multi-channel high-repetition-frequency large-dynamic-range distance and speed measuring laser radar method and device
CN113702992A (en) * 2020-05-23 2021-11-26 北醒（北京）光子科技有限公司 Laser detection device
CN111650601A (en) * 2020-06-01 2020-09-11 杭州爱莱达科技有限公司 High-resolution 3D imaging method and device for vehicle-mounted coherent laser radar
CN111650601B (en) * 2020-06-01 2022-10-25 孙建锋 High-resolution 3D imaging method and device for vehicle-mounted coherent laser radar
CN111896973A (en) * 2020-07-16 2020-11-06 武汉大学 Ultra-long-distance target three-dimensional motion trajectory prediction method based on active and passive fusion
CN111896973B (en) * 2020-07-16 2023-01-17 武汉大学 Ultra-long-distance target three-dimensional motion trajectory prediction method based on active and passive fusion
CN112230238B (en) * 2020-12-09 2021-04-23 武汉光谷航天三江激光产业技术研究院有限公司 Laser intensity modulation distance and speed measuring method and system, terminal device and storage medium
CN112230238A (en) * 2020-12-09 2021-01-15 武汉光谷航天三江激光产业技术研究院有限公司 Laser intensity modulation distance and speed measuring method and system, terminal device and storage medium
CN112731396A (en) * 2020-12-22 2021-04-30 华中科技大学 Synthetic aperture radar millimeter wave imaging method and system based on in-phase signal measurement
CN112731396B (en) * 2020-12-22 2023-12-01 华中科技大学 Synthetic aperture radar millimeter wave imaging method and system based on in-phase signal measurement
CN112965078A (en) * 2021-02-04 2021-06-15 郜键 AMCW long-distance laser imaging device based on MSM detection
CN112965078B (en) * 2021-02-04 2024-02-09 苏州奥瑞图光电科技有限公司 AMCW long-distance laser imaging device based on MSM detection
CN113109834A (en) * 2021-04-16 2021-07-13 中国人民解放军国防科技大学 High-energy and high-precision underwater three-dimensional imaging laser radar system and method
CN113835074A (en) * 2021-08-04 2021-12-24 南京常格科技发展有限公司 People flow dynamic monitoring method based on millimeter wave radar
CN113835074B (en) * 2021-08-04 2024-01-16 南京常格科技发展有限公司 Dynamic people flow monitoring method based on millimeter wave radar
WO2023029393A1 (en) * 2021-08-31 2023-03-09 上海禾赛科技有限公司 Balanced detector and frequency modulation continuous wave radar
CN114938662A (en) * 2021-10-13 2022-08-23 深圳市速腾聚创科技有限公司 Laser radar and control method of laser radar
WO2023065149A1 (en) * 2021-10-20 2023-04-27 深圳市速腾聚创科技有限公司 Laser radar and laser radar control method
CN115210603A (en) * 2021-10-20 2022-10-18 深圳市速腾聚创科技有限公司 Laser radar and laser radar control method
CN115508859A (en) * 2022-11-11 2022-12-23 武汉光谷航天三江激光产业技术研究院有限公司 Laser three-dimensional imaging method and system based on single balanced detector
CN115902920B (en) * 2023-02-23 2023-06-02 中国人民解放军国防科技大学 Coherent and incoherent laser cooperative detection method and system for air moving target
CN115902920A (en) * 2023-02-23 2023-04-04 中国人民解放军国防科技大学 Coherent and incoherent laser cooperative detection method and system for aerial moving object
CN116930995A (en) * 2023-09-19 2023-10-24 天津大学四川创新研究院 System and method for measuring speed and distance of high-speed target of frequency modulation continuous wave laser
CN116930995B (en) * 2023-09-19 2023-11-28 天津大学四川创新研究院 System and method for measuring speed and distance of high-speed target of frequency modulation continuous wave laser
CN117872322A (en) * 2024-03-12 2024-04-12 北醒（北京）光子科技有限公司 Frequency modulation continuous wave laser radar and radar navigation system

Also Published As

Publication number Publication date
CN110806586B (en) 2020-04-14

Similar Documents

Publication Publication Date Title
CN110806586B (en) Non-scanning linear frequency modulation continuous wave speed and distance measuring laser three-dimensional imaging method and device
CN106707291B (en) Double-frequency linear frequency modulation coherent wind lidar
WO2022134136A1 (en) Frequency-modulated continuous-wave lidar system and lidar scanning method
CN111650601B (en) High-resolution 3D imaging method and device for vehicle-mounted coherent laser radar
CN110780310B (en) Polarization diversity dual-channel speed measuring and distance measuring coherent laser radar measuring method and device
CN109343077B (en) Liquid crystal phased array ghost imaging system and imaging method thereof
CN111337902B (en) Multi-channel high-repetition-frequency large-dynamic-range distance and speed measuring laser radar method and device
US5504719A (en) Laser hydrophone and virtual array of laser hydrophones
EP3465269A1 (en) Coherent lidar system using tunable carrier-suppressed single-sideband modulation
CN110794421B (en) Pseudo-random code time delay self-differential interference three-dimensional imaging laser radar method and device
CN111999739A (en) Coherent laser radar method and device for measuring distance and speed by phase modulation
CN103823221A (en) Pulse laser coherent wind measuring radar
CN107703517A (en) Airborne multiple beam optical phased array laser three-dimensional imaging radar system
CN109991623A (en) A kind of distribution type laser radar
WO2021036315A1 (en) Microwave and laser radar integration method and apparatus
CN104931974A (en) Light source modulation and demodulation-based ICMOS high-speed 3D imaging laser radar
CN105785389A (en) Three-dimensional imaging laser radar system
CN104965206B (en) Cross-polarization is multiplexed synthetic aperture laser imaging radar
CN108957471A (en) Three-dimension measuring system based on FM-CW laser ranging
CN115015886A (en) Double-channel pseudo-random code phase modulation distance measuring and speed measuring laser radar method and device
CN114152951A (en) Frequency-adjustable continuous wave laser radar detection method and system
Yang et al. Photonic THz InISAR for 3D positioning with high resolution
US7417744B2 (en) Coherent hybrid electromagnetic field imaging
CN110133679A (en) A kind of Doppler range rate measuring system based on single-chip integration two-frequency laser
CN104111451A (en) Difference interference synthetic aperture laser three-dimensional imaging radar transceiving device

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant
TR01 Transfer of patent right

Effective date of registration: 20220915

Address after: Room 1803, No. 12, Lane 333, Hongshi Road, Juyuan New District, Jiading District, Shanghai, 201800

Patentee after: Sun Jianfeng

Address before: 310053 room 701, block B, 581 torch Avenue, Puyan street, Binjiang District, Hangzhou City, Zhejiang Province

Patentee before: HANGZHOU ILIDAR TECHNOLOGY CO.,LTD.

TR01 Transfer of patent right