Semiconductor laser based parallel ranging and three-dimensional imaging system and method

Abstract

This invention discloses a parallel ranging and 3D imaging system and method based on semiconductor lasers, belonging to the field of laser ranging and imaging. The system includes: a laser source emission module capable of emitting n modulated laser signals in parallel to illuminate the target object; a laser echo receiving and front-end signal processing module capable of simultaneously receiving n target echo laser signals scattered or reflected from multiple directions by the n modulated laser signals, and outputting one analog composite signal after processing; a single-channel high-speed analog-to-digital conversion module capable of converting the analog composite signal into a digital sequence superimposed signal; a digital signal processing and control module capable of demodulating the digital sequence superimposed signal to obtain n phase information and target distance; and a distance information transmission and 3D imaging module capable of generating a 3D point cloud based on the target distance of each channel to achieve 3D imaging. This invention reduces hardware complexity and cost, and is applicable to the fields of autonomous driving, robot navigation, and 3D perception in consumer electronics.

Description

Technical Field

[0001] This invention relates to the fields of photoelectric detection technology, laser ranging and three-dimensional imaging technology, and in particular to a parallel ranging and three-dimensional imaging system and method based on semiconductor lasers. Background Technology

[0002] Current laser ranging and 3D imaging technologies typically use a single laser source for measurement. While this achieves basic distance measurement and imaging functions, it has many shortcomings in complex scenarios. For example, the scanning speed of a single laser source is relatively slow, making it difficult to meet the real-time requirements of applications. Moreover, the accuracy of distance measurement is significantly affected when dealing with objects with large differences in surface reflectivity. Simultaneously, the imaging resolution of a single laser source is extremely low, making it difficult to obtain high-precision 3D information and failing to meet the real-time imaging needs of dynamic scenes. Area array laser sources suffer from low integration, large size, high power consumption, and severe crosstalk between channels.

[0003] Current mainstream 3D laser ranging systems mostly employ a single laser source combined with mechanical rotation, galvanometers, or MEMS scanning to acquire distance information by scanning the scene point-by-point or line-by-line. However, this approach has the following drawbacks: Single-beam serial scanning only obtains distance information for one or a few points within a single measurement cycle. To complete the 3D reconstruction of a single frame of a scene, a large number of single-point measurements need to be accumulated over a long period, resulting in a limited frame rate and difficulty in meeting the real-time imaging requirements of high-speed moving targets or dynamic scenes. Mechanical or MEMS scanning structures require high-precision motion control, leading to system complexity, wear and tear on moving parts, and insufficient long-term reliability, making them unsuitable for stable operation in complex environments over extended periods.

[0004] Mechanical rotation or galvanometer scanning mechanisms occupy a large volume and have complex drive and control circuits, making it difficult to further reduce the overall size and weight of the device, which is not conducive to its promotion in applications sensitive to size and weight, such as automotive, drones, and home robots. On the other hand, solutions using multi-channel independent transmitters and multi-channel independent analog-to-digital converters (ADCs) consume large amounts of hardware resources, resulting in high costs, high power consumption, and difficulties in system integration. In traditional solutions, the laser transmitting module, receiving module, and signal processing module are often implemented separately, resulting in a large number of components, complex wiring, and low overall system integration.

[0005] In view of this, the present invention is hereby proposed. Summary of the Invention

[0006] The purpose of this invention is to provide a parallel ranging and three-dimensional imaging system and method based on semiconductor lasers, which can realize parallel emission and echo reception of multiple lasers, demodulate the signals of each frequency and calculate the time of flight to obtain multi-channel distance data, and realize real-time, high-resolution three-dimensional imaging of the target scene by reconstructing high-resolution three-dimensional point clouds, thereby solving the above-mentioned technical problems existing in the prior art.

[0007] The objective of this invention is achieved through the following technical solution:

[0008] A parallel ranging and three-dimensional imaging system based on a semiconductor laser includes:

[0009] The multi-channel laser emission module can be controlled by a connected signal processing and control module to drive n light-emitting units to emit n modulated laser signals with different and orthogonal modulation frequencies and non-overlapping frequency domains in parallel to illuminate the target object in the target scene, where n is greater than 2.

[0010] The echo receiver and front-end signal processing module is connected to a single-channel high-speed analog-to-digital converter. It can be controlled by the connected signal processing control module to simultaneously receive n target echo signals returning from multiple directions. After photoelectric conversion and amplification, it outputs a single analog composite signal containing n target echo signals of different frequencies to the single-channel high-speed analog-to-digital converter.

[0011] A single-channel high-speed analog-to-digital converter connects the echo receiver and the front-end signal processing module. It can convert the analog composite signal output from the echo receiver and the front-end signal processing module into a digital sequence superposition signal and output it to the signal processing control module.

[0012] The signal processing and control module, connected to the three-dimensional imaging module, can demodulate the received digital sequence superimposed signal to obtain preprocessed data, obtain the phase information of the separated n target echo signals through phase separation, calculate the target distance of the n target echo signals using the phase information, and send it to the three-dimensional imaging module.

[0013] The 3D imaging module can generate a high-resolution 3D image of the target object using the target distance from the received n-channel target echo signals.

[0014] A parallel ranging and three-dimensional imaging method based on a semiconductor laser for the system described in this invention includes:

[0015] Step 1: Through the system's multi-channel laser emission module and controlled by the signal processing and control module, n light-emitting units are driven to emit n modulated laser signals with different and orthogonal modulation frequencies that do not overlap in the frequency domain, which are then used to illuminate the target object in the target scene. n is greater than 2.

[0016] Step 2: The system's echo receiver and front-end signal processing module simultaneously receive n target echo signals of different frequencies returning from multiple directions. After photoelectric conversion and amplification, the system outputs a single analog composite signal containing n target echo signals of different frequencies to the system's single-channel high-speed analog-to-digital converter.

[0017] Step 3: The received analog composite signal is converted into a digital sequence superposition signal by a single-channel high-speed analog-to-digital converter and output to the signal processing and control module.

[0018] Step 4: The received digital sequence superimposed signal is demodulated by the signal processing control module to obtain preprocessed data. The phase information of the separated n target echo signals is obtained by phase separation. The target distance of the n target echo signals is calculated using the phase information and sent to the three-dimensional imaging module of the system.

[0019] Step 5: The three-dimensional imaging module generates a high-resolution three-dimensional image of the target object using the target distance from the received n-channel target echo signals.

[0020] Compared with existing technologies, the parallel ranging and three-dimensional imaging system and method based on semiconductor lasers provided by this invention have the following advantages:

[0021] By integrating a multi-laser emitting module capable of simultaneously emitting multiple laser beams to illuminate a target object for distance measurement, coupled with an echo receiving and front-end signal processing module capable of simultaneously receiving multiple target echo signals and aliasing them into a single analog composite signal, and combining demodulation processing by the signal processing control module with 3D imaging processing by the 3D imaging module, the speed and accuracy of target object distance measurement and the resolution of 3D imaging are significantly improved. This makes it suitable for scenarios requiring high-speed, high-precision 3D perception, such as autonomous driving, robot environment modeling, industrial quality inspection, and security monitoring. Since all components are semiconductor components, high integration is achieved, eliminating the need for mechanical rotation or galvanometer scanning mechanisms, reducing system size and power consumption, and ensuring long-term operational reliability. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 A block diagram of a parallel ranging and three-dimensional imaging system based on a semiconductor laser provided in an embodiment of the present invention.

[0024] Figure 2A schematic diagram of a parallel ranging and three-dimensional imaging system based on a semiconductor laser provided in an embodiment of the present invention.

[0025] Figure 3 This is a block diagram of the signal processing control module of a parallel ranging and three-dimensional imaging system based on a semiconductor laser, provided in an embodiment of the present invention.

[0026] Figure 4 This is a schematic diagram of the signal processing control module of the parallel ranging and three-dimensional imaging system based on semiconductor lasers provided in an embodiment of the present invention.

[0027] Figure 5 A flowchart of a parallel ranging and three-dimensional imaging method based on semiconductor lasers provided in an embodiment of the present invention.

[0028] Figure 6 The flowchart illustrates the specific processing steps of the parallel ranging and three-dimensional imaging method based on semiconductor lasers provided in this embodiment of the invention.

[0029] Figure 7 This is a waveform diagram of the aliasing signal provided in an embodiment of the present invention.

[0030] Figure 8 The diagram shows the original aliased signal waveform and the waveform of the signal after ADC sampling of the system provided in the embodiment of the present invention.

[0031] Figure 9 This is a schematic diagram of the waveforms of each frequency component signal demodulated by the system provided in this embodiment of the invention. Detailed Implementation

[0032] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the specific content of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments, which do not constitute a limitation of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0033] First, the following explanations are provided for the terms that may be used in this article:

[0034] The term "and / or" means that either or both can be achieved simultaneously. For example, X and / or Y means that it includes both "X" or "Y" as well as the three cases of "X and Y".

[0035] The terms "comprising," "including," "containing," "having," or other similar semantic descriptions should be interpreted as non-exclusive inclusion. For example, including a technical feature element (such as raw material, component, ingredient, carrier, dosage form, material, size, part, component, mechanism, device, step, process, method, reaction conditions, processing conditions, parameter, algorithm, signal, data, product or article of manufacture, etc.) should be interpreted as including not only the expressly listed technical feature element, but also other technical feature elements that are not expressly listed and are well-known in the art.

[0036] The term "composed of" excludes any technical features not expressly listed. When used in a claim, it closes the claim to exclude all technical features other than those expressly listed, except for associated conventional impurities. If the term appears only in a clause of a claim, it limits the claim to the elements expressly listed in that clause; elements recited in other clauses are not excluded from the overall claim.

[0037] Unless otherwise explicitly specified or limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this document according to the specific circumstances.

[0038] The terms “center,” “longitudinal,” “lateral,” “length,” “width,” “thickness,” “upper,” “lower,” “front,” “back,” “left,” “right,” “vertical,” “horizontal,” “top,” “bottom,” “inner,” “outer,” “clockwise,” and “counterclockwise” indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience and simplification of description and do not imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this document.

[0039] The solution provided by this invention will be described in detail below. Contents not described in detail in the embodiments of this invention are prior art known to those skilled in the art. Where specific conditions are not specified in the embodiments of this invention, they shall be performed according to conventional conditions in the art or conditions recommended by the manufacturer. Reagents or instruments used in the embodiments of this invention whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0040] like Figure 1 , Figure 2As shown, an embodiment of the present invention provides a parallel ranging and three-dimensional imaging system based on a semiconductor laser, comprising:

[0041] The system comprises a multi-channel laser emission module, an echo reception and front-end signal processing module, a single-channel high-speed analog-to-digital converter, a signal processing and control module, and a 3D imaging module; among which:

[0042] The multi-channel laser emitting module is electrically connected to the signal processing and control module. Under the control of the signal processing and control module, it can drive n light-emitting units to emit n modulated laser signals in parallel to illuminate the target object in the target scene. The modulation frequencies of the n modulated laser signals are different and orthogonal to each other, and they do not overlap in the frequency domain. n is greater than 2.

[0043] The echo receiving and front-end signal processing module is electrically connected to the signal processing control module and the single-channel high-speed analog-to-digital converter, respectively. Under the control of the signal processing control module, it can simultaneously receive n target echo signals scattered or reflected back from multiple directions by n modulated laser signals emitted by the multi-channel laser emitting module, and after photoelectric conversion and amplification of the n target echo signals, output a single analog composite signal containing n target echo signals of different frequencies to the single-channel high-speed analog-to-digital converter.

[0044] The single-channel high-speed analog-to-digital converter is electrically connected to the signal processing control module and can convert the analog composite signal output by the echo receiver and the front-end signal processing module into a digital sequence superimposed signal and output it to the signal processing control module.

[0045] The signal processing control module is communicatively connected to the three-dimensional imaging module. It can perform fast Fourier transform and frequency domain demodulation on the digital sequence superimposed signal output by the single-channel high-speed analog-to-digital converter. Based on the phase information of the n target echo signals separated by demodulation, the target distance of the n target echo signals is calculated based on the phase information of the n target echo signals and sent to the three-dimensional imaging module.

[0046] The three-dimensional imaging module can receive the target distance of n target echo signals calculated by the signal processing control module, combine the target distance of the n target echo signals to generate a three-dimensional point cloud, and perform filtering, fusion and visualization processing on the three-dimensional point cloud to generate a high-resolution three-dimensional image of the target object.

[0047] Preferably, in the above system, the multi-channel laser emission module includes:

[0048] A multiplexer digital-to-analog converter, a driver circuit, and a vertical-cavity surface-emitting laser array with n light-emitting units; wherein,

[0049] A multi-channel digital-to-analog converter is electrically connected to a vertical-cavity surface-emitting laser array with n light-emitting units via a driving circuit, and is also electrically connected to the signal processing control module. Each digital-to-analog converter can convert the digital modulation signal from the signal processing control module into an analog driving current, which drives the corresponding n light-emitting units of the vertical-cavity surface-emitting laser array via the driving circuit, so that the n light-emitting units emit n modulated laser signals in parallel. The modulation frequencies of the n modulated laser signals are all different and orthogonal to each other, and they do not overlap in the frequency domain, where n is greater than 2.

[0050] Preferably, in the above system, the echo reception and front-end signal processing module includes:

[0051] The optical system has n detectors corresponding to the n light-emitting units of the multi-channel laser emitting module. The optical axis of each detector and the optical axis of the light-emitting unit corresponding to the multi-channel laser emitting module satisfy the transmit-receive alignment relationship in the optical system. Each detector can receive the target echo signal of the corresponding light-emitting unit.

[0052] Preferably, in the above system, each detector uses a single-photon avalanche diode.

[0053] See Figure 3 Preferably, in the above system, the signal processing control module adopts a circuit based on a field-programmable gate array (FPGA) chip, which includes:

[0054] The system comprises a global timing control unit, a multi-channel modulation signal generation unit, an echo signal acquisition and frequency domain separation unit, a phase separation calculation unit, a distance information calculation unit, and a data communication interface unit; among which...

[0055] The global timing control unit is connected to the multi-channel modulation signal generation unit, the echo signal acquisition and frequency domain separation unit, and the phase separation and calculation unit, respectively. It can generate a unified clock signal for each unit to synchronize the timing of each unit.

[0056] The multi-channel modulation signal generation unit is connected to the multi-channel laser emission module via the multi-channel digital-to-analog converter. It has n digital orthogonal modulation channels, each of which is connected to a light-emitting unit in the multi-channel laser emission module. It can generate a digital frequency synthesis signal of a specific frequency as a carrier through digital frequency synthesis, so that the modulation envelopes of the n laser signals emitted by the multi-channel laser emission module are orthogonally arranged on the frequency domain spectrum.

[0057] The echo signal acquisition and frequency domain separation unit is connected to the single-channel high-speed analog-to-digital converter. It can receive the superimposed digital sequence signal output by the single-channel high-speed analog-to-digital converter and perform digital filtering and fast Fourier transform on the superimposed digital sequence signal to obtain preprocessed data.

[0058] The phase separation and calculation unit is connected to the echo signal acquisition and frequency domain separation unit. It can receive the preprocessed data output by the echo signal acquisition and frequency domain separation unit and perform phase calculation to obtain the phase information of the separated n target echo signals.

[0059] The distance information calculation unit is connected to the phase separation and resolution unit, and can receive the phase information of the n target echo signals output by the phase separation and resolution unit and perform distance calculation to obtain the target distance of the n target echo signals.

[0060] The data communication interface unit is communicatively connected to the distance information calculation unit and the three-dimensional imaging module, and can output the target distance of the n target echo signals obtained by the distance information calculation unit to the three-dimensional imaging module.

[0061] The aforementioned phase separation and calculation unit can perform phase calculation on the preprocessed data in the following manner, specifically including:

[0062] Receives n in-phase components I from the digital quadrature demodulation channel (FPGA logic section) after accumulation and averaging. i and orthogonal components Q i (where i = 1, 2…n); For the i-th signal, the phase delay Δφ is calculated using the arctangent function (CORDIC). i The calculation formula is: Δφ i = arctan(Q i / I i The final output is the phase information of n target echo signals.

[0063] The aforementioned distance information calculation unit can calculate the target distance of n target echo signals in the following manner, specifically including:

[0064] The phase delay Δφ calculated by the phase separation solution unit i The target distance D between the multi-channel laser emission module and the corresponding point of the target object is converted into the following formula. i For i=1,2…n, the formula for calculating the target distance is: D i =(c×Δφ i ) / (4π×f i ), where c is the speed of light, f i The target distance D is obtained by using the modulation frequency of the i-th target echo signal transmitted. i This refers to the target distance of the n target echo signals.

[0065] Preferably, in the above system, each digital quadrature modulation channel in the multi-channel modulation signal generation unit includes:

[0066] Baseband signal generator, digital frequency synthesizer, and quadrature mixer; among which,

[0067] The baseband signal generator is electrically connected to the quadrature mixer unit, and can generate a baseband signal and output it to the quadrature mixer unit;

[0068] The digital frequency synthesizer is electrically connected to the quadrature mixer unit and can generate in-phase carriers and quadrature carriers as local oscillator signals, and output them to the quadrature mixer unit.

[0069] The quadrature mixing unit can mix the baseband signal output by the baseband signal generator with the local oscillator signal output by the digital frequency synthesizer to generate a digital modulation signal containing a specific frequency, and output the digital modulation signal to the digital-to-analog converter circuit.

[0070] The global timing control unit includes: a master clock, a global clock network, and a phase-locked loop; wherein...

[0071] The master clock is connected to the multi-channel modulation signal generation unit, the echo signal acquisition and frequency domain separation unit, and the phase separation and calculation unit via a global clock network, and can generate a unified clock signal for each unit.

[0072] The phase-locked loop, connected to the global clock network, can multiply, divide, and adjust the phase of the input reference clock signal to generate the operating clocks required by the system at each level, including the sampling clock, DSP processing clock, and interface clock, and distribute them to each unit through the global clock network to ensure system timing synchronization.

[0073] The echo signal acquisition and frequency domain separation unit includes: a high-speed data buffer, a digital filter bank, and a fast Fourier transform kernel connected in sequence; wherein...

[0074] The high-speed data buffer is connected to the single-channel high-speed analog-to-digital converter and can receive the superimposed digital sequence signal output by the single-channel high-speed analog-to-digital converter.

[0075] The digital filter bank can perform digital filtering on the superimposed digital sequence signal received by the high-speed data buffer;

[0076] The Fast Fourier Transform kernel can perform Fast Fourier Transform on the signal after digital filtering of the digital filter bank to obtain preprocessed data.

[0077] The data communication interface unit adopts a high-speed serial interface. This high-speed serial interface enables high-speed data interaction between the distance information calculation unit and the 3D imaging module, sending the processed distance information of the n target echo signals to the 3D imaging module. Specifically, the high-speed serial interface serves as a communication connection between the signal processing control module (based on a field-programmable gate array chip) and the external computer running the 3D imaging module, allowing for data transmission and the receipt of configuration commands from the computer.

[0078] Preferably, in the above system, the digital frequency synthesizer generates in-phase and quadrature carriers as local oscillator signals in the following manner:

[0079] The unified system clock based on the global timing control unit generates a pair of quadrature carrier signals as local oscillator signals. The pair of quadrature carrier signals includes an in-phase carrier I. i and orthogonal carrier Q i , among which, I i =cos(2πf i t), Q i =sin(2πf i t)), f i A unique modulation frequency is assigned to the i-th laser signal, and t is the emission time of each laser signal. The frequency interval Δf between adjacent channels is precisely set by configuring the frequency control word. The set value of Δf satisfies Δf≥B+B g Where B is the signal modulation bandwidth, B g To prevent aliasing and protect bandwidth.

[0080] Preferably, in the above system, the signal processing control module performs Fast Fourier Transform and frequency domain demodulation on the superimposed digital sequence signal output by the single-channel high-speed analog-to-digital converter to obtain preprocessed data, including:

[0081] Step 31, pre-emphasis processing: Perform equalization filtering on the superimposed digital sequence signal sent by the single-channel high-speed analog-to-digital converter to compensate for transmission link loss, and obtain the time-domain waveform;

[0082] Step 32, Fast Fourier Transform: The time-domain waveform obtained in step 31 is converted into a frequency-domain spectrum using a 1024-point Fast Fourier Transform with a processing delay of ≤200ns.

[0083] Step 33, Bandpass filtering and quadrature demodulation: Configure the center frequency f for the frequency domain spectrum of each target frequency. i A digital bandpass filter with a bandwidth of ±5MHz is used to extract the corresponding frequency components. After the components are extracted by the digital bandpass filter, the in-phase and quadrature components are extracted by quadrature demodulation as preprocessed data to recover the amplitude and phase information of each target echo signal.

[0084] Preferably, in the above system, the signal processing control module performs phase separation based on preprocessed data to obtain the phase information of the separated n target echo signals, and then calculates the target distance of the n target echo signals based on the phase information of the n target echo signals, including:

[0085] Step 41, Calculate the phase delay: Based on the in-phase component I extracted from each laser signal as preprocessed data. i and orthogonal components Q i The phase delay Δφ of the i-th target echo signal relative to the corresponding emitted laser signal is calculated using the arctangent function. i The formula for calculating the arctangent function is: Δφ i =arctan(Q i / I i );

[0086] Step 42, calculate the target distance: calculate the phase delay Δφ obtained in step 41. i The target distance D between the multi-channel laser emission module and the corresponding point of the target object is converted into the following formula. i For i=1,2…n, the formula for calculating the target distance is: D i =(c×Δφ i ) / (4π×f i ), where c is the speed of light, f i Given the modulation frequency of the i-th emitted laser signal, the target distance D is obtained. i This refers to the target distance of the n target echo signals.

[0087] See Figure 4 The present invention also provides a parallel ranging and three-dimensional imaging method based on a semiconductor laser for the above-described system, comprising:

[0088] Step 1, Laser emission and parallel irradiation:

[0089] Through the system's multi-channel laser emission module, and controlled by the system's signal processing and control module, n light-emitting units are driven to emit n modulated laser signals with different and orthogonal modulation frequencies that do not overlap in the frequency domain, which are then directed to the target object in the target scene, where n is greater than 2.

[0090] Step 2, Echo reception and signal synthesis:

[0091] The system's echo receiver and front-end signal processing module simultaneously receive n target echo signals of different frequencies scattered or reflected from multiple directions. After photoelectric conversion and amplification, the system outputs a single analog composite signal containing the n target echo signals of different frequencies to the system's single-channel high-speed analog-to-digital converter.

[0092] Step 3, Modulus-to-Digital Conversion:

[0093] The received analog composite signal is synchronously sampled and converted into a digital sequence superposition signal by a single-channel high-speed analog-to-digital converter, and then output to the signal processing and control module.

[0094] Step 4, Demodulation and target distance calculation:

[0095] The received digital sequence superimposed signal is demodulated by the signal processing and control module to obtain preprocessed data. The phase information of the separated n target echo signals is obtained through phase separation. The target distance of the n target echo signals is calculated using the phase information and sent to the three-dimensional imaging module of the system.

[0096] Specifically, in step 4 above, the signal processing control module performs frequency domain demodulation on the digital sequence superposition signal obtained in step 3, and separates the i-th target echo signal for each frequency fᵢ. Based on the in-phase component I extracted from each target echo signal at different frequencies... i and orthogonal components Q i The phase delay Δφ of the i-th target echo signal relative to the emitted laser signal is calculated using the arctangent function. i The calculation formula is: Δφ i = arctan(Q i / I i The phase delay is converted into the target distance Dᵢ between the corresponding points of the multi-channel laser emission module and the target object, i=1,2…n. The formula for calculating the target distance is: D i = (c×Δφ i ) / (4π×f i ), where c is the speed of light, f i Let be the modulation frequency of the i-th target echo signal, and the obtained target distance Dᵢ is the target distance of the n-th target echo signal;

[0097] Step 5, 3D imaging:

[0098] The three-dimensional imaging module uses the target distance from the received n target echo signals to generate a high-resolution three-dimensional image of the target object.

[0099] Specifically, in step 5 above, the target distance Dᵢ and the corresponding channel position information of the obtained n-channel target echo signals are sent to the three-dimensional imaging module of the system. The three-dimensional imaging module calculates the three-dimensional coordinates of each point according to the target distance Dᵢ and channel position information corresponding to each channel to obtain a three-dimensional point cloud. The three-dimensional point cloud is then filtered, fused and visualized to generate a high-resolution real-time three-dimensional image of the target object being measured.

[0100] The system and method of the present invention have at least the following advantages compared with the prior art:

[0101] (1) Achieve multi-channel parallel ranging, significantly improving frame rate and real-time performance:

[0102] By using a multi-channel laser emission module, a semiconductor laser array emits multiple laser signals of different frequencies in parallel within the same emission cycle to illuminate the target object in the target scene. Distance information from multiple measurement points can be acquired simultaneously, significantly improving data throughput and 3D imaging frame rate. This is suitable for scenarios with high real-time requirements, such as autonomous driving and robotics.

[0103] (2) Using a single ADC to achieve multi-channel distance measurement simplifies the system architecture and reduces costs:

[0104] By using quadrature modulation and digital demodulation, multiple target echo signals of different frequencies are superimposed and then sampled by a single ADC. This eliminates the need for an independent analog-to-digital conversion circuit for each laser channel, reducing hardware complexity, system cost, and power consumption, and facilitating the miniaturization and integration of the system.

[0105] (3) High ranging accuracy and high 3D imaging resolution:

[0106] Employing the Time-of-Flight (TOF) ranging principle, high-precision distance measurement is achieved by accurately measuring the flight time of each laser signal and utilizing the stability of the speed of light. Leveraging a VCSEL array serving as a multi-channel laser emission module and high-density signal sampling, high point cloud density and high spatial resolution 3D imaging can be realized within a relatively small volume.

[0107] (4) The system has a high degree of integration, a simple structure, and no mechanical scanning mechanism:

[0108] It adopts a semiconductor laser array electronic scanning method, which eliminates the mechanical rotating mirror or galvanometer scanning structure, avoids mechanical wear and adjustment complexity, improves system reliability and shock resistance, and reduces size and weight, making it suitable for automotive, airborne and mobile platform applications.

[0109] (5) Adaptable to complex environments and strong anti-interference ability:

[0110] By designing multiple orthogonal laser signals of different frequencies, the signal of each channel can be effectively distinguished in the digital domain and spectral aliasing can be suppressed. Combined with front-end filtering and threshold decision, the signal-to-noise ratio and ranging stability are improved in harsh environments such as strong background light and smoke.

[0111] To more clearly demonstrate the technical solution and its effects provided by the present invention, the following detailed description of the solution provided by the embodiments of the present invention is provided with reference to specific examples.

[0112] Example 1

[0113] like Figure 1 , Figure 2 As shown, this embodiment provides a parallel ranging and 3D imaging system based on semiconductor lasers. It achieves parallel transmission and echo reception of multiple laser signals of different frequencies under the same clock source. The receiver uses a single-channel high-speed analog-to-digital converter to sample one hybrid echo analog signal. An FPGA is used to demodulate each frequency signal and calculate the time-of-flight (TOF) to obtain multi-channel distance data. A high-resolution 3D point cloud is then reconstructed using a computer, enabling real-time, high-resolution 3D imaging of the target scene. The system includes:

[0114] The system includes a multi-channel laser emission module, an echo reception and front-end signal processing module, a high-speed analog-to-digital converter, a signal processing control module, and a 3D imaging module. These modules are synchronized and linked via the same clock and control signals.

[0115] (1) Multi-channel laser emission module:

[0116] (11) A vertical cavity surface-emitting laser (VCSEL) array is used as a semiconductor laser source. The array can be A×B independent light-emitting units, and each light-emitting unit corresponds to a measurement channel in space.

[0117] (12) Through the laser driving circuit, under the control of the FPGA of the signal processing control module, n modulated laser signals of different frequencies and mutually orthogonal are generated, and the laser signals of each frequency are f1, f2, ..., fn. n ;

[0118] (13) The laser signals of different frequencies emitted can be orthogonally frequency modulated to ensure that each signal is distinguishable and orthogonal to each other in the frequency domain, thus avoiding spectral aliasing during demodulation.

[0119] (14) The transmission power of each channel can be adjusted as needed to adapt to target objects with different distances and reflectivities, thereby achieving a certain degree of dynamic range extension.

[0120] (2) Echo reception and front-end signal processing module:

[0121] (21) A single-photon avalanche diode (SPAD) is used as a detector to receive multi-channel target echo signals reflected from the surface of the target object.

[0122] (22) After analog signal processing such as preamplification and filtering, the echo signal outputs a single analog composite signal. This single analog composite signal is an aliased signal containing n target echo signals of different frequencies (see...). Figure 6 ).

[0123] (23) By using reasonable bandwidth design and noise suppression measures, ensure that the aliased signal has a sufficient signal-to-noise ratio before entering the high-speed analog-to-digital converter for analog-to-digital conversion.

[0124] (3) High-speed analog-to-digital converter:

[0125] (31) A single-channel high-speed analog-to-digital converter (ADC) is used to sample and digitize the analog composite signal output by the echo receiver and front-end signal processing module, and convert it into a digital sequence superposition signal.

[0126] (32) The output digital sequence superposition signal contains f1, f2, ..., f n The superimposed signals of various frequency components retain the amplitude and phase information of all channels, which facilitates subsequent demodulation and time delay measurement.

[0127] (4) Signal processing and control module:

[0128] See Figure 3 and Figure 4 The signal processing control module uses an FPGA as its core control and digital signal processing unit, and its functions include:

[0129] (41) Generate laser emission control signal.

[0130] (42) Perform parallel digital signal processing on the superimposed digital sequence signal output by the ADC. Using digital filtering and a Fast Fourier Transform (FFT) algorithm, separate the target echo signal corresponding to each frequency component from the superimposed digital sequence signal. See [link to relevant documentation]. Figure 7 , Figure 8 .

[0131] (43) The in-phase component I extracted from the target echo signal of each channel at different frequencies i and orthogonal components Q i The phase delay Δφ of the i-th target echo signal relative to the emitted laser signal is calculated using the arctangent function. i The calculation formula is: Δφ i = arctan(Q i / I i The phase delay is converted into the target distance Dᵢ between the corresponding point of the multi-channel laser emission module and the target object. The formula for calculating the target distance Dᵢ is: D i =(c×Δφ i ) / (4π×f i ), where c is the speed of light, f i Let be the modulation frequency of the i-th laser signal; the target distances D1, D2, ..., D of the n-th target echo signals are obtained from the target distance Dᵢ. n That is, multi-channel distance data.

[0132] (44) The distance data of each channel and the corresponding channel number, timestamp and other information are transmitted in real time to the three-dimensional imaging module running on the host computer through the USB communication interface.

[0133] like Figure 3 As shown, the signal processing control module uses a field-programmable gate array (FPGA) based circuit, which includes the following logic units:

[0134] The system includes a global timing control unit, a multi-channel modulation signal generation unit, an echo signal acquisition and frequency domain separation unit, a phase separation and calculation unit, and a data communication interface unit.

[0135] The specific connection relationships and functions of each logic unit are as follows:

[0136] (411) Multi-channel Modulation Signal Generation Unit (corresponding to function 41) This unit is connected to the multi-channel laser emission module and is used to generate laser emission control signals to realize function 41. Composition and function: This unit integrates n direct digital frequency synthesizers (DDS signals). Under the synchronous drive of the global timing control unit, each DDS signal generates a sine wave digital sequence of different frequencies according to the preset frequency control word. The sequences are superimposed by the internal adder of the FPGA or output independently to the digital-to-analog converter (DAC), thereby driving the laser source to emit a modulated laser signal containing n frequency components.

[0137] (412) Echo Signal Acquisition and Frequency Domain Separation Unit (corresponding to Function 42) The input of this unit is connected to the analog-to-digital converter (ADC), and the output is connected to the phase separation and calculation unit. It is used to realize the parallel processing and component separation of the digital sequence superimposed signal in Function 42. Composition and function: This unit includes a high-speed data buffer FIFO, a digital filter bank, and a fast Fourier transform (FFT) processing core. First, the digital sequence superimposed signal output by the ADC is received through the data buffer FIFO; second, out-of-band noise is filtered out using the digital filter bank; finally, the time-domain signal is sent to the FFT processing core for parallel operation to convert the signal from the time domain to the frequency domain. On the frequency domain spectrum, according to the n frequency point indices preset by the transmitter, the complex values ​​(including the real part Real and the imaginary part Imag) corresponding to each frequency component are extracted, thereby realizing the separation of the target echo signal corresponding to each frequency component from the superimposed signal.

[0138] (413) Phase Separation and Calculation Unit (corresponding to Function 43) This unit is connected to the echo signal acquisition and frequency domain separation unit and is used to implement the phase extraction calculation of Function 43. Structure and Function: This unit internally contains a coordinate rotation digital calculator (CORDIC algorithm core) and a floating-point multiplier and divider. Phase Extraction: The real part of the separated i-th frequency signal is taken as the in-phase component I. i The imaginary part is used as the orthogonal component Q. i Input into the CORDIC core and execute the calculation Δφ i = arctan(Q i / I i ), calculate the phase delay Δφ of the i-th target echo signal relative to the emitted laser signal. i ; obtain the phase information of the separated n target echo signals.

[0139] (414) Distance Information Calculation Unit: This unit is connected to the phase separation and calculation unit and is used to calculate distance information. Structure and Function: It calculates the calculated phase delay Δφ. i The target distance D between the multi-channel laser emission module and the corresponding point of the target object is converted into the following formula. i For i=1,2…n, the formula for calculating the target distance is: D i =(c×Δφ i ) / (4π×f i ), where c is the speed of light, f i Given the modulation frequency of the i-th emitted laser signal, the target distance D is obtained. i This refers to the target distance of the n target echo signals.

[0140] (415) Data Communication Interface Unit (corresponding to Function 44) The input of this unit is connected to the distance information calculation unit, and the output is connected to the external USB physical layer interface, used to implement data transmission for Function 44. Structure and Function: This unit includes a data packetizer and a USB protocol controller. Its function is to package the calculated n-channel distance data with the current channel number, system timestamp (provided by the global timing control unit), and check bit, and send the data packet to the host computer's 3D imaging module in real time according to the USB communication protocol standard.

[0141] (5) Three-dimensional imaging module:

[0142] (51) The host computer is a computer, and the three-dimensional imaging module runs on the computer that serves as the host computer. The three-dimensional imaging module receives the distance information Dᵢ of the n target echo signals separated from the FPGA output of the signal processing control module, as well as the corresponding channel address information (which can be mapped to the horizontal angle θᵢ, pitch angle φᵢ and sensor pose parameters (Rᵢ, tᵢ) in the target space).

[0143] (52) Calculate the three-dimensional coordinates xᵢ of each measurement point in the three-dimensional coordinate system according to the three-dimensional coordinate transformation relationship: xᵢ = tᵢ+Dᵢ×Rᵢ×[cosφᵢcosθᵢ,cosφᵢsinθᵢ,sinφᵢ]ᵀ.

[0144] (53) The three-dimensional point cloud data is obtained by summarizing the coordinates of all channels and continuous three-dimensional points. The point cloud is then processed by filtering and denoising, removing outliers, smoothing interpolation, and edge enhancement to generate a high-resolution three-dimensional image, thereby realizing real-time three-dimensional reconstruction and display of the target scene.

[0145] Example 2

[0146] See Figure 5 , Figure 6 This embodiment provides a parallel ranging and three-dimensional imaging method based on semiconductor lasers, applicable to the system of Embodiment 1, and includes the following steps:

[0147] Step 1, Laser emission and parallel irradiation:

[0148] Under the control of the same clock source of the system's signal processing control module, the FPGA of the signal processing control module drives the VCSEL laser array, which serves as a multi-channel laser emission module, to generate n modulated laser signals of different frequencies and mutual orthogonality. Each laser signal is emitted at a predetermined time sequence and frequency f1, f2, ..., f3. n Parallel emission, illuminating multiple spatial locations within the target scene.

[0149] Step 2, Laser echo reception and signal synthesis:

[0150] The target echo signals scattered or reflected from multiple directions are received by the SPAD detector of the system's echo receiver and front-end signal processing module. After front-end amplification and filtering, a single analog composite signal is output, which contains the superposition of n target echo signals of different frequencies.

[0151] Step 3, Analog-to-Digital Conversion and Digital Waveform Acquisition:

[0152] The analog composite signal output from the echo receiver and front-end signal processing module is input into a single high-speed ADC for synchronous sampling and analog-to-digital conversion, resulting in a signal containing f1, f2, ..., f... n A superimposed signal of digital sequences of each frequency component.

[0153] Step 4, Digital demodulation and target distance calculation:

[0154] In the FPGA of the signal processing control module, the digital sequence superimposed signal is demodulated in the frequency domain. The i-th target echo signal is separated for each frequency fᵢ. The in-phase component I is extracted from each target echo signal at different frequencies. i and orthogonal components Q i The phase delay Δφ of the i-th target echo signal relative to the emitted laser signal is calculated using the arctangent function. i The calculation formula is: Δφ i =arctan(Q i / I i The phase delay calculation is converted into the target distance D between the corresponding points of the multi-channel laser emission module and the target object being measured. i The calculation formula is: D i =(c×Δφ i ) / (4π×f i ), where c is the speed of light, f i Let be the modulation frequency of the i-th laser signal, and let be the distance D from the target. i Obtain n-way distance information D1, D2, ..., D n See Figure 9 .

[0155] Step 5, 3D coordinate calculation and 3D imaging:

[0156] The obtained n-channel distance information Dᵢ and the position information of each channel are sent to the 3D imaging module running on the computer. The 3D imaging module calculates the 3D coordinates of each point according to the angle parameters corresponding to each channel, obtains 3D point cloud data, and performs filtering, fusion and visualization processing on the 3D point cloud data to generate a high-resolution 3D image of the target object, realizing real-time 3D imaging.

[0157] In summary, the system and method of this invention can simultaneously acquire multi-channel distance information by transmitting multiple orthogonal laser signals of different frequencies in parallel within the same emission cycle, acquiring and demodulating multiple echo signals through a single analog-to-digital conversion channel. While ensuring high ranging accuracy and high 3D imaging resolution, it significantly improves system frame rate and real-time performance; reduces hardware complexity and power consumption; and achieves high integration, miniaturization, and cost reduction of laser emission, reception, and signal processing, thereby improving system stability and practical application capabilities in complex environments. This system and method meet the requirements for real-time performance, ranging accuracy, 3D imaging resolution, system size, and power consumption in applications such as autonomous driving, robot navigation, industrial inspection, and security monitoring. This invention achieves a qualitative improvement in frame rate, point cloud density, and dynamic scene response capability through a parallel multi-point simultaneous acquisition and mapping mode. It has the advantages of being all-solid-state, high frame rate, high precision, and strong anti-interference, making it easier to achieve large-scale application in fields such as national defense, aerospace, autonomous driving, and digital twins. It has good scalability and industrialization prospects, and can evolve towards higher integration, lower cost, and stronger intelligence along the direction of "array-chip-intelligence".

[0158] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. The storage medium can be a magnetic disk, optical disk, read-only memory (ROM), or random access memory (RAM), etc.

[0159] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims. The information disclosed in the background section is intended only to enhance the understanding of the overall background technology of the present invention and should not be construed as an admission or implication in any way that such information constitutes prior art known to those skilled in the art.

Claims

1. A parallel ranging and three-dimensional imaging system based on a semiconductor laser, characterized in that, include: The multi-channel laser emission module can be controlled by a connected signal processing and control module to drive n light-emitting units to emit n modulated laser signals with different and orthogonal modulation frequencies and non-overlapping frequency domains in parallel to illuminate the target object in the target scene, where n is greater than 2. The multi-channel laser emission module includes: a multi-channel digital-to-analog converter, a driving circuit, and a vertical-cavity surface-emitting laser array with n emitting units; wherein, A multi-channel digital-to-analog converter is electrically connected to a vertical-cavity surface-emitting laser array with n light-emitting units via a driving circuit, and is also electrically connected to the signal processing and control module. Each digital-to-analog converter can convert the digital modulation signal from the signal processing and control module into an analog driving current, which drives the corresponding n light-emitting units of the vertical-cavity surface-emitting laser array via the driving circuit, so that the n light-emitting units emit n modulated laser signals in parallel. The modulation frequencies of the n modulated laser signals are different and orthogonal to each other, and they do not overlap in the frequency domain, where n is greater than 2. The echo receiver and front-end signal processing module is connected to a single-channel high-speed analog-to-digital converter. It can be controlled by the connected signal processing control module to simultaneously receive n target echo signals returning from multiple directions. After photoelectric conversion and amplification, it outputs a single analog composite signal containing n target echo signals of different frequencies to the single-channel high-speed analog-to-digital converter. The echo receiving and front-end signal processing module includes: n detectors corresponding to the number of n light-emitting units of the multi-channel laser emitting module. The optical axis of each detector and the optical axis of the light-emitting unit corresponding to the multi-channel laser emitting module satisfy the transmit-receive alignment relationship in the optical system. Each detector can receive the target echo signal of the corresponding light-emitting unit. A single-channel high-speed analog-to-digital converter connects the echo receiver and the front-end signal processing module. It can convert the analog composite signal output from the echo receiver and the front-end signal processing module into a digital sequence superposition signal and output it to the signal processing control module. The signal processing and control module, connected to the three-dimensional imaging module, can demodulate the received digital sequence superimposed signal to obtain preprocessed data, obtain the phase information of the separated n target echo signals through phase separation, calculate the target distance of the n target echo signals using the phase information, and send it to the three-dimensional imaging module. The 3D imaging module can generate a high-resolution 3D image of the target object using the target distance from the received n-channel target echo signals.

2. The parallel ranging and three-dimensional imaging system based on a semiconductor laser according to claim 1, characterized in that, Its features are, Each detector uses a single-photon avalanche diode.

3. The parallel ranging and three-dimensional imaging system based on semiconductor lasers according to claim 1, characterized in that, The signal processing control module employs a circuit based on a field-programmable gate array (FPGA) chip, which includes: The system comprises a global timing control unit, a multi-channel modulation signal generation unit, an echo signal acquisition and frequency domain separation unit, a phase separation calculation unit, a distance information calculation unit, and a data communication interface unit; among which... The global timing control unit is connected to the multi-channel modulation signal generation unit, the echo signal acquisition and frequency domain separation unit, and the phase separation and calculation unit, respectively. It can generate a unified clock signal for each unit to synchronize the timing of each unit. The multi-channel modulation signal generation unit is connected to the multi-channel laser emission module via the multi-channel digital-to-analog converter. It has n digital orthogonal modulation channels, each of which is connected to a light-emitting unit in the multi-channel laser emission module. It can generate a digital frequency synthesis signal of a specific frequency as a carrier through digital frequency synthesis, so that the modulation envelopes of the n laser signals emitted by the multi-channel laser emission module are orthogonally arranged on the frequency domain spectrum. The echo signal acquisition and frequency domain separation unit is connected to the single-channel high-speed analog-to-digital converter. It can receive the superimposed digital sequence signal output by the single-channel high-speed analog-to-digital converter and perform digital filtering and fast Fourier transform on the superimposed digital sequence signal to obtain preprocessed data. The phase separation and calculation unit is connected to the echo signal acquisition and frequency domain separation unit. It can receive the preprocessed data output by the echo signal acquisition and frequency domain separation unit and perform phase calculation to obtain the phase information of the separated n target echo signals. The distance information calculation unit is connected to the phase separation and resolution unit, and can receive the phase information of the n target echo signals output by the phase separation and resolution unit and perform distance calculation to obtain the target distance of the n target echo signals. The data communication interface unit is communicatively connected to the distance information calculation unit and the three-dimensional imaging module, and can output the target distance of the n target echo signals obtained by the distance information calculation unit to the three-dimensional imaging module.

4. The parallel ranging and three-dimensional imaging system based on a semiconductor laser according to claim 3, characterized in that, Each digital quadrature modulation channel in the multi-channel modulation signal generation unit includes: Baseband signal generator, digital frequency synthesizer, and quadrature mixer; among which, The baseband signal generator is electrically connected to the quadrature mixer unit, and can generate a baseband signal and output it to the quadrature mixer unit; The digital frequency synthesizer is electrically connected to the quadrature mixer unit and can generate in-phase carriers and quadrature carriers as local oscillator signals, and output them to the quadrature mixer unit. The quadrature mixing unit can mix the baseband signal output by the baseband signal generator with the local oscillator signal output by the digital frequency synthesizer to generate a digital modulation signal containing a specific frequency, and output the digital modulation signal to the digital-to-analog converter circuit. The global timing control unit includes: a master clock, a global clock network, and a phase-locked loop; wherein... The master clock is connected to the multi-channel modulation signal generation unit, the echo signal acquisition and frequency domain separation unit, and the phase separation and calculation unit via a global clock network, and can generate a unified clock signal for each unit. The phase-locked loop, connected to the global clock network, can multiply, divide, and adjust the phase of the input reference clock signal to generate the operating clocks required by the system at each level, including the sampling clock, DSP processing clock, and interface clock, and distribute them to each unit through the global clock network to ensure system timing synchronization. The echo signal acquisition and frequency domain separation unit includes: a high-speed data buffer, a digital filter bank, and a fast Fourier transform kernel connected in sequence; wherein... The high-speed data buffer is connected to the single-channel high-speed analog-to-digital converter and can receive the superimposed digital sequence signal output by the single-channel high-speed analog-to-digital converter. The digital filter bank can perform digital filtering on the superimposed digital sequence signal received by the high-speed data buffer; The Fast Fourier Transform kernel can perform Fast Fourier Transform on the signal after digital filtering of the digital filter bank to obtain preprocessed data. The data communication interface unit adopts a high-speed serial interface.

5. The parallel ranging and three-dimensional imaging system based on a semiconductor laser according to claim 4, characterized in that, The digital frequency synthesizer generates in-phase and quadrature carriers as local oscillator signals in the following manner: A pair of quadrature carrier signals are generated as local oscillator signals based on a uniform system clock provided by a global timing control unit, the pair of quadrature carrier signals including an in-phase carrier I i and a quadrature carrier Q i , where I i =cos(2πf i t), Q i =sin(2πf i t), f i is a unique modulation frequency assigned to the i-th laser signal, and t is the emission time of each laser signal. A frequency control word is configured to accurately set the frequency interval Δf between laser signals of adjacent channels, with the set value of Δf satisfying Δf≥B+B g , where B is the signal modulation bandwidth, and B g is the anti-aliasing protection bandwidth.

6. The parallel ranging and three-dimensional imaging system based on a semiconductor laser according to claim 1, characterized in that, The signal processing control module performs Fast Fourier Transform and frequency domain demodulation on the superimposed digital sequence signal output by the single-channel high-speed analog-to-digital converter to obtain preprocessed data, including: Step 31, pre-emphasis processing: Perform equalization filtering on the superimposed digital sequence signal sent by the single-channel high-speed analog-to-digital converter to compensate for transmission link loss, and obtain the time-domain waveform; Step 32, Fast Fourier Transform: The time-domain waveform obtained in step 31 is converted into a frequency-domain spectrum using a 1024-point Fast Fourier Transform with a processing delay of ≤200ns. Step 33, Bandpass filtering and quadrature demodulation: Configure a digital bandpass filter with a center frequency of fᵢ and a bandwidth of ±5MHz for the frequency domain spectrum of each target frequency. After extracting the corresponding frequency components through the digital bandpass filter, extract the in-phase component and quadrature component through quadrature demodulation as preprocessed data.

7. The parallel ranging and three-dimensional imaging system based on a semiconductor laser according to claim 6, characterized in that, The signal processing control module performs phase separation based on preprocessed data to obtain the phase information of the separated n target echo signals, and then calculates the target distance of the n target echo signals based on the phase information of the n target echo signals, including: Step 41, Calculate the phase delay: Based on the in-phase component I extracted from each laser signal as preprocessed data. i and orthogonal components Q i The phase delay Δφ of the i-th target echo signal relative to the corresponding emitted laser signal is calculated using the arctangent function. i The formula for calculating the arctangent function is: Δφ i =arctan(Q i / I i ); Step 42, calculate the target distance: calculate the phase delay Δφ obtained in step 41. i The target distance D between the multi-channel laser emission module and the corresponding point of the target object is converted into the following formula. i For i=1,2…n, the formula for calculating the target distance is: D i =(c×Δφ i ) / (4π×f i ), where c is the speed of light, f i Given the modulation frequency of the i-th emitted laser signal, the target distance D is obtained. i This refers to the target distance of the n target echo signals.

8. A parallel ranging and three-dimensional imaging method based on a semiconductor laser for use in the system of any one of claims 1-7, characterized in that, include: Step 1: Through the system's multi-channel laser emission module and controlled by the signal processing and control module, n light-emitting units are driven to emit n modulated laser signals with different and orthogonal modulation frequencies that do not overlap in the frequency domain, which are then used to illuminate the target object in the target scene. n is greater than 2. Step 2: The system's echo receiver and front-end signal processing module simultaneously receive n target echo signals of different frequencies returning from multiple directions. After photoelectric conversion and amplification, the system outputs a single analog composite signal containing n target echo signals of different frequencies to the system's single-channel high-speed analog-to-digital converter. Step 3: The received analog composite signal is converted into a digital sequence superposition signal by a single-channel high-speed analog-to-digital converter and output to the signal processing and control module. Step 4: The received digital sequence superimposed signal is demodulated by the signal processing control module to obtain preprocessed data. The phase information of the separated n target echo signals is obtained by phase separation. The target distance of the n target echo signals is calculated using the phase information and sent to the three-dimensional imaging module of the system. Step 5: The three-dimensional imaging module generates a high-resolution three-dimensional image of the target object using the target distance from the received n-channel target echo signals.

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