CN116626692A

CN116626692A - Laser radar detection system and detection method

Info

Publication number: CN116626692A
Application number: CN202210132268.5A
Authority: CN
Inventors: 雷述宇; 宋一铄
Original assignee: Ningbo Abax Sensing Electronic Technology Co Ltd
Current assignee: Ningbo Abax Sensing Electronic Technology Co Ltd
Priority date: 2022-02-14
Filing date: 2022-02-14
Publication date: 2023-08-22

Abstract

The laser radar detection system is characterized by comprising a driving signal generation part, wherein the driving signal generation part acts on a laser source through a laser modulation driving circuit, and the laser source receives the driving signal and drives and emits a pulse type detection laser sequence; an array type return light receiving module for receiving a return light signal reflected by the detected object in the field of view and generating a return signal; the counting sequence splicing module is used for obtaining a copying splicing signal according to the return signal, and the processing module is used for generating a modulating signal according to the driving signal generated by the driving signal generating part and obtaining a signal related to the distance with the copying splicing signal according to a preset rule operation, and outputting the distance information of a final detected object according to the signal related to the distance.

Description

Laser radar detection system and detection method

Technical Field

The application relates to the technical field of detection, in particular to a laser radar detection system and a detection method.

Background

The principle of the active detection system, which is realized by especially using a laser source, is that the light source actively emits detected emitted light, for example, near infrared type detected light, the wavelength of which can be selected to be in the range of 800-1200nm, but the active detection system is not limited thereto, and the near infrared type detected wave can also ensure the safety when an artificial object exists in the field of view, so that the near infrared type active detection system is more and more commonly applied to various scenes, such as subsequent automatic driving, intelligent door locks, security camera shooting, mobile phone three-dimensional camera shooting, and the like.

Time of flight ("TOF") light detection and ranging ("LIDAR") is a technique for remote distance measurement. The TOF LIDAR sensor determines the distance between an instrument including the sensor and the object by measuring the time required for a laser pulse to propagate between the instrument and the object.

Currently widely used detection methods include indirect time of flight (ITOF) measurement schemes and direct time of flight (DTOF) measurement schemes. Most of the indirect flight time measurement schemes adopt a method for measuring phase offset, namely, the phase difference between a transmitted wave and a received wave, the abscissa of the transmitted wave and the received wave is time t, the ordinate is light intensity, and the flight time t can be obtained according to the phase difference of the transmitted wave and the received wave, so that the distance of a detected object can be obtained according to d=ct/2. The direct flight time measurement scheme generally directly obtains the time difference between the triggering of the transmitting end and the triggering of the corresponding receiving end through a picosecond-level resolution measurement system (SPAD+TDC is adopted), namely the flight time t, so that the distance of a detected object is calculated. There is a type called coherent detection, in which a coherent laser signal and a local laser oscillation signal are incident together on a photosensitive surface of a detector under the condition of meeting wavefront matching (i.e. the same phase relationship is maintained on the photosensitive surface of the whole laser detector), so as to generate beat frequency or coherent superposition, and the magnitude of an output electric signal of the detector is proportional to the square of the sum of a laser signal wave to be detected and a local laser oscillation wave, and the detection mode has advantages of itself, but has great disadvantages in terms of pixel level, rapid processing and efficient utilization of emission energy.

In recent years, some laser radar principles of direct time-of-flight detection (incoherent) have been developed, and a detection technology known by more people is gradually changed, and patent application number CN202010604232.3 is a new type of laser ranging method and laser radar system, and proposes a new type of detection mechanism, in which the coherent light principle is not adopted on the optical path, but correlation operation is performed at the electrical signal stage, and the distance or other information of the final detected object is further obtained through the correlation operation of the electrical signal, however, in practice, the method has the following limiting characteristics (1) as known from the incoherent chirp signal amplitude modulation continuous wave laser three-dimensional imaging principle, the difference frequency signal is generated by multiplying the delayed chirp signal with the local oscillation signal. From the viewpoint of energy utilization, the gain of the detector needs to be modulated at a high speed, so that the detection efficiency of the prior art is low, and the range is small; (2) The prior art adopts devices such as a broadband amplifier, a mixer, an A/D (analog/digital) and the like, and the dynamic range of the devices limits the dynamic range of a received laser signal, thereby limiting the dynamic receiving range of the prior art; (3) The performance of the laser three-dimensional imaging system realized by the prior art is greatly influenced by the chirp signal frequency modulation linearity and the frequency modulation flatness.

The patent application number 202111112299.6 is a laser radar detection system, and compared with the prior art, a counting sequence generating module is added, which converts a photon counting sequence or an accumulated photon counting sequence into an adaptive photon counting sequence or an adaptive accumulated photon counting sequence respectively, and generates an accumulated counting sequence after being processed by a digital multiplier and a preset rule operation module, and similarly, the target information can be solved by analyzing the spectrum characteristics of the accumulated counting sequence.

The target distance is obtained by analyzing the frequency spectrum of the accumulated counting sequence, and the element number of the accumulated counting sequence is equal to the pulse number M contained in the laser pulse sequence. The larger M is, the higher the spectrum signal to noise ratio is, and the smaller the spectral line interval is, so that the smaller ranging deviation can be realized.

Therefore, in the above prior art, there is a contradiction between the laser emission energy and the ranging bias.

Therefore, in order to overcome the foregoing technical problems, there is a need to develop a more efficient detection method and detection system, which can utilize smaller laser emission energy to achieve smaller ranging deviation.

Disclosure of Invention

The present application aims to overcome the above-mentioned drawbacks of the prior art, and provides a laser radar detection system and method for acquiring distance, so as to realize smaller ranging deviation by using smaller laser emission energy.

In order to achieve the above purpose, the technical scheme adopted by the embodiment of the application is as follows:

in a first aspect, an embodiment of the present application provides a laser radar detection system, which is characterized by comprising a driving signal generating portion, wherein the driving signal generating portion acts on a laser source through a laser modulation driving circuit, and the laser source receives the driving signal and drives and emits a pulse type detection laser sequence; an array type return light receiving module for receiving a return light signal reflected by the detected object in the field of view and generating a return signal; the counting sequence splicing module is used for obtaining a copying splicing signal according to the return signal, the processing module is used for generating a modulating signal according to the driving signal generated by the driving signal generating part and obtaining a signal related to the distance with the copying splicing signal according to a preset rule operation, and the processing module is used for outputting the distance information of the final detected object according to the signal related to the distance.

Optionally, the laser source emits a detection laser sequence in less than one detection period to obtain a return signal, and the counting sequence splicing module replicates the return signal of the detection laser sequence emitted in the less than one detection period, splices the return signal to obtain the replication splicing signal.

Optionally, the laser light source emits a detection laser sequence in a detection period to obtain a return signal, and the counting sequence splicing module copies part of elements of the return signal of the detection laser sequence emitted in the detection period and calculates the elements with the return signal to obtain the copy splicing signal.

Optionally, based on the last copy-splice signal, the counting sequence splicing module replicates a part of elements of the last copy-splice signal and computes the part of elements with the last copy-splice signal to obtain the copy-splice signal.

Optionally, the lidar detection system further comprises a counting sequence generation module that generates an adaptive counting sequence based on the return signal.

In a second aspect, the present invention proposes a laser radar detection system using the first aspect, including a driving signal generating part, where the driving signal generating part acts on a laser source through a laser modulation driving circuit, and the laser source receives the driving signal and drives and emits a pulse type detection laser sequence; an array type return light receiving module for receiving a return light signal reflected by the detected object in the field of view and generating a return signal; the counting sequence splicing module is used for obtaining a copying splicing signal according to the return signal, the processing module is used for generating a modulating signal according to the driving signal generated by the driving signal generating part and obtaining a signal related to the distance with the copying splicing signal according to a preset rule operation, and the processing module is used for outputting the distance information of the final detected object according to the signal related to the distance.

Optionally, the laser light source emits a detection laser sequence in a detection period to obtain a return signal, and the counting sequence splicing module replicates part of elements in the return signal of the detection laser sequence emitted in the detection period and calculates the return signal to obtain the replication splicing signal.

Optionally, the system further comprises a counting sequence generating module, wherein the counting sequence generating module generates an adaptive counting sequence according to the return signal.

The beneficial effects of the application are as follows: the application provides a laser radar detection system which is characterized by comprising a driving signal generation part, wherein the driving signal generation part acts on a laser source through a laser modulation driving circuit, and the laser source receives the driving signal to drive and emit a pulse type detection laser sequence; an array type return light receiving module for receiving a return light signal reflected by the detected object in the field of view and generating a return signal; the counting sequence splicing module is used for obtaining a copying splicing signal according to the return signal, and the processing module is used for generating a modulating signal according to the driving signal generated by the driving signal generating part and obtaining a signal related to the distance with the copying splicing signal according to a preset rule operation, and outputting the distance information of a final detected object according to the signal related to the distance.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram of a modularized working principle of a detection system according to an embodiment of the present application;

FIG. 2 is a schematic diagram of a detection scheme provided in the prior art;

FIG. 3 is a schematic diagram of a pulsed detection scheme according to an embodiment of the present application;

fig. 4 is a schematic diagram of an array-type receiving module according to an embodiment of the present application;

FIG. 5 is a schematic diagram of a counting sequence result of a return light statistic of an emitted L-time laser sequence according to an embodiment of the present application;

FIG. 6 is a schematic diagram of a preset rule calculation module according to an embodiment of the present application;

FIG. 7 is a schematic diagram of a modulation sequence for generating discrete type using a driving signal according to an embodiment of the present application;

fig. 8 is a schematic diagram of acquiring a distance-related signal by using a preset rule operation module according to an embodiment of the present application;

FIG. 9 is a schematic diagram of another embodiment of the present application for acquiring a distance-related signal by using a preset rule calculation module;

FIG. 10 is a schematic diagram of obtaining a distance-related signal according to an embodiment of the present application;

FIG. 11 is a schematic diagram of a three-dimensional imaging system according to an embodiment of the present application;

FIG. 12 is a flowchart of an adaptive counting sequence for generating according to an embodiment of the present application;

FIG. 13 is a flowchart of a sequence for generating an adaptive accumulation count according to an embodiment of the present application;

FIG. 14 is a flowchart of yet another adaptive counting sequence for generating an adaptive count according to an embodiment of the present application;

FIG. 15 is a flowchart of an adaptive accumulation count sequence generated according to a pre-generated adaptive correction sequence according to an embodiment of the present application;

FIG. 16 is a schematic diagram of a detection system according to an embodiment of the present application;

FIG. 17 is a schematic diagram of a detection system according to an embodiment of the present application;

FIG. 18 is a schematic diagram of a resulting replication splice sequence according to an embodiment of the present application;

FIG. 19 is a schematic diagram of another resulting replication splice sequence provided by an embodiment of the present application;

fig. 20 is a schematic waveform diagram of three-dimensional imaging according to an embodiment of the present application.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present application more apparent, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application, and it is apparent that the described embodiments are some embodiments of the present application, but not all embodiments of the present application. The components of the embodiments of the present application generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the application, as presented in the figures, is not intended to limit the scope of the application, as claimed, but is merely representative of selected embodiments of the application. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.

It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures.

The detection systems currently employed basically comprise: the light source module 110, the processing module 120, and the light receiving module 130, where the light source module 110 includes, but is not limited to, a semiconductor laser, a solid state laser, or other types of lasers, when the semiconductor laser is used as the light source, a Vertical-cavity surface emitting laser VCSEL (Vertical-cavity surface-emitting laser) or an edge-emitting semiconductor laser EEL (edge-emitting laser) is used, and the light source module 110 emits a sine wave or a square wave or a triangular wave, or a pulse wave, or the like, and in the ranging application, most of the lasers having a certain wavelength, for example, infrared lasers (most preferably near infrared lasers with a wavelength of 950nm, etc.), the emitted light is projected into the field of view, the detected object 140 existing in the field of view may reflect the projected lasers to form return light, and the return light enters the detection system to be captured by the light receiving module 130, and the light receiving module 130 may include a photoelectric conversion part, where the four-phase delay receiving scheme in the ITOF ranging can be most commonly used to obtain a four-phase delay signal, and the four-phase delay receiving scheme is used to calculate the four-phase delay signal, and the four-delay signal is 90 ° and the four-phase-delay signal is calculated (the four-phase-delay signal is 90 ° and the four-phase-delay signal is 90) and the four-phase-delay signal is calculated by the four-phase, and the four-phase-delay signal is 90) and the four-phase angle is 90, and the four-phase delay time is the four phase, and the phase delay time and the receiving point, the receiving system is 0, and the receiving phase, and the receiving phase and the receiving system, and the receiving device:

The ratio of the difference of A1 and A3 to the difference of A2 and A4 is equal to the tangent of the phase angle. ArcTan is effectively a bivariate arctangent function, which can be mapped to the appropriate quadrant, defined as 0 ° or 180 ° when a2=a4 and a1> A3 or a3> A1, respectively.

The distance to the target is determined by the following formula:

to this end, it is also necessary to determine the frequency of the emitted laser light, where c is the speed of light,is the phase angle (measured in radians) and f is the modulation frequency. The above scheme can realize the effect of detecting the distance of the detected object in the field of view, the scheme is called a four-phase delay scheme to obtain detection results, of course, the receiving module generates different information by photoelectric conversion, in some cases, the information acquisition of the detected object is also realized by using a 0-degree and 180-degree two-phase scheme, and the target information is obtained by three phases of 0 degree, 120 degrees and 240 degrees, even the five-phase delay scheme is also disclosed in the literature, and the invention is not particularly limited.

In DTOF ranging, since the pixel unit of the array sensor is a SPAD (single photon avalanche photodiode) device, the array sensor works in a geiger mode, in the geiger mode, the avalanche photodiode absorbs photons to generate electron-hole pairs, the electron-hole pairs are accelerated under the action of a strong electric field generated by high reverse bias voltage, so that enough energy is obtained, then the electron-hole pairs collide with a crystal lattice to form a linkage effect, and a large number of electron-hole pairs are formed to cause avalanche phenomenon, and the current grows exponentially. The gain of the SPAD is theoretically infinite, a single photon can saturate the photocurrent of the SPAD, so that the SPAD becomes the first choice of a high-performance single photon detection system, the ranging principle is very simple, a light source emits pulse laser with a certain pulse width, for example, a few nanoseconds level, the pulse laser is reflected by a detection target and returns to an array type receiving module containing the SPAD in an avalanche state, a detection unit in the avalanche state can receive a returned signal, the distance between the detection system and the detection target can be output through the processing of the processing module, the detection is finished, a laser pulse can be emitted for tens of thousands times for obtaining a high-reliability result, the detection unit obtains a statistical result, thus a more accurate distance can be obtained through the processing of the statistical result, the following table 1 shows that the two more-application type ITOF ranging methods and the DTOF ranging method have certain limitations through the comparison of the table 1, and a novel detection method needs to be developed to obtain a more accurate and more interference-resistant result.

TABLE 1 ITOF vs. DTOF ranging methods

Fig. 2 shows a scheme for obtaining information such as a detected object distance by using incoherent (direct detection scheme) disclosed in the prior art, the driving signal generating part generates a driving signal, where the driving signal may be a driving signal with an identification function, for example, a period of the driving signal is gradually increased or gradually decreased, a driving signal with a certain characteristic and an identification effect may be obtained by a specific function or an internal algorithm, a chirp signal is taken as an example here, but the actual implementation is not limited to the driving signal, the driving signal acts on a laser emitter through a laser modulation circuit, the driving signal is a continuous wave laser, thereby emitting a detection laser with a rule similar to that of the driving signal, a returned laser signal is formed after reflection of the detected object in the field of view, a delayed returned light signal may be obtained in different areas of the light receiving module due to a difference in the distance between the detected object in the field of view, an output signal after the frequency mixer is obtained by photoelectric conversion of the receiving module, an output signal after the mixer is obtained by correlation with the driving signal inside the mixer is subjected to a bandwidth amplifier, a signal processor processes the output signal after the mixer may obtain a difference signal, wherein the output signal after the mixer comprises a low-pass filter and a high-pass signal is converted to a high-noise signal, a high-frequency signal is obtained after the difference signal is obtained by a high-frequency-channel-noise signal is obtained by a high-channel conversion, and a high-frequency-channel noise signal is obtained by a high-channel digital interference signal is obtained after the high-frequency conversion is obtained by a high-frequency channel conversion, and a high-quality digital signal is obtained by a high-quality digital signal is obtained, the frequency spectrum of the difference frequency signal can be obtained through time-frequency domain conversion, and finally, the final detection result of information such as the speed, the distance and the like of a detected object related to the frequency spectrum characteristic is identified through the characteristic such as the peak characteristic of the frequency spectrum, and of course, in order to ensure that the frequency domain converted signal meets the detection requirement, the time-frequency domain conversion module further comprises a threshold detection unit, an information resolving unit and the like, and in fig. 2, a driving signal generator is taken as a chirp signal generator for further explanation, the chirp signal generator generates two paths of chirp signals, one path of the chirp signal serves as a local oscillation signal of a mixer, and the other path of chirp signal is sent into a laser modulation driving circuit, so that the laser power emitted by a continuous wave laser changes according to the following rule:

P _t (t)＝P _t0 [1+m _t cos(2πf ₀ t+πkt ² +θ ₀ )]，t∈[0,T] (3)

Wherein P is _t0 The average emission power of the laser; m is m _t Modulation depth for transmission; f (f) ₀ Is the initial frequency of the chirp signal; t is time; k is the frequency modulation slope and k=b/T (B is the chirp bandwidth, T is the chirp period), θ ₀ Is the initial phase.

The receiving optical system focuses the laser signal reflected by the target to the photoelectric detector, the delayed chirp signal is obtained through photoelectric conversion, the signal is amplified and mixed with the local oscillation signal, and the difference frequency signal is obtained through low-pass filtering. Wherein the delayed chirp signal is:

A _r (t)＝A _r0 [1+m _t cos(2πf ₀ (t-τ)+πk(t-τ) ² +θ ₀ +φ ₀ )]，t∈[τ,T+τ] (4)

wherein A is _r0 Is the average amplitude of the delayed chirp signal; phi (phi) ₀ An additional phase introduced for the target reflection; τ=2r/c (R is the target relative distance and c is the speed of light in vacuum) is the time the laser travels to and from the target and the rangefinder.

The local oscillation signal is:

A _LO (t)＝A _LO0 [1+m _LO cos(2πf ₀ t+πkt ² +θ _LO )]，t∈[0,T] (5)

wherein A is _LO0 For the average amplitude of local oscillation signal, m _LO For local oscillation signal modulation depth, theta _LO The initial phase of the local oscillation signal.

The difference frequency signal is:

wherein A is _IF For the amplitude of the difference frequency signal,is the phase of the difference frequency signal.

Amplifying the difference frequency signal, performing A/D, obtaining a frequency spectrum through Fast Fourier Transform (FFT), and performing threshold detection on the frequency spectrum to obtain the difference frequency signal with the frequency of:

according to the relation between the frequency of the difference frequency signal and the target relative distance, the target relative distance is obtained as follows:

Although this incoherent type of detection technique can complement to some extent some of the drawbacks of ITOF and DTOF and even of coherent detection methods, the above-mentioned prior art still suffers from the following limitations in detection:

(1) The three-dimensional imaging principle of incoherent chirp signal amplitude modulation continuous wave laser is known, and the difference frequency signal is generated by multiplying the delayed chirp signal and the local oscillation signal. From the energy utilization perspective, the difference frequency signal energy in the A/D sampling interval is not utilized because the A/D is carried out on the difference frequency signal, and the delayed chirp signal energy is in direct proportion to the emission energy of the continuous wave laser, so that the laser average emission power of the prior art (incoherent chirp signal amplitude modulation continuous wave laser three-dimensional imaging) is higher, and the ranging range is smaller;

(2) As can be seen from fig. 2 and the description of the system operation principle, the prior art adopts wideband amplifiers, mixers, a/D devices, etc., and the dynamic range of these devices limits the dynamic range of the received laser signal, thus limiting the dynamic receiving range of the prior art;

(3) The performance of the laser three-dimensional imaging system realized by the prior art is greatly influenced by the chirp signal frequency modulation linearity and the frequency modulation flatness.

Because of the technical problems of the existing incoherent type detection method, the huge complexity of data volume and the like in data processing, the inventor of the present invention proposes an improved type detection method and detection system, as shown in fig. 3, wherein the system adopts a pulse type laser, so that the emitted active type detection laser is a pulse laser sequence segment composed of a pulse sequence, a driving signal generating part in the system generates a driving signal, the driving signal can adopt a chirp signal similar to the previous example, and can also adopt other types of driving signals, the essential characteristics of the driving signal is that the emitted laser of the device is modulated to obtain an emitted light signal with identifiable characteristics, the driving signal acts on the pulse type laser through a laser modulation driving circuit, the laser may utilize at least part of the characteristics of the driving signal, for example, the total period of the driving signal is taken as the period of the pulse sequence segment, the single pulse in the pulse segment may be selected as the scheme that the peak values are the same or similar, the peak value duration is the same or similar, or the amplitude information of the driving signal is taken as the peak basis of the pulse sequence, the peak values contained in the pulse sequence may be different at this time, even the decreasing or increasing rule of the small period in the segment of the driving signal may be taken as the basis of the triggering probability of the pulse in the emitted laser segment to generate the pulse laser segment in non-equidistant configuration, etc., where the specific implementation scheme of the pulse laser segment emitted by the pulse laser source is not limited, the emitted pulse laser sequence is reflected by the object to be detected in the field of view to generate the return light signal, the return light signal is received by the photodetector to form the photon counting sequence, the preset rule operation module included in the processing module generates a discontinuous modulation sequence Y by using the driving signal, on the other hand, the distance correlation signal can be obtained by performing operation on the photon counting sequence and the modulation sequence Y according to the preset rule, the distance correlation signal is further processed by the time-frequency domain conversion module to obtain a frequency spectrum signal converted by the distance correlation signal, and features of the frequency spectrum signal, such as peak features (including highest peak information, next highest peak information or peak information in a region of interest, etc.), output the detected object distance information, speed information, etc., which are not particularly limited herein, and similarly, for a pulse type discontinuous detection scheme, the time-frequency domain conversion module includes a unit capable of performing time-frequency domain conversion processing, which may perform wavelet operation, segmentation FFT, FFT, chirp-Z operation, DFT, etc., although specific algorithm implementation is not described in detail herein, which is only exemplified herein, and the time-frequency domain conversion module may also include a threshold detection unit and/or an information calculation unit, which are not limited herein.

The light receiving module may be an array type receiving module as shown in fig. 4, in which the array type receiving module includes a pixel unit 410 formed of diodes, in practical implementation, m×n pixel units may be used to form an active area of the array type receiving module, the pixel unit formed of which may be on the order of tens of thousands or hundreds of thousands, etc., which is not limited herein, the array type receiving module may include a lens portion 4301 and a probe unit base portion 4302, the lens portion 4301 includes a plurality of lens units, the lens units may be formed of micro lens units having a predetermined curvature, and of course, in order to ensure maximum utilization of the return light, the lens portion may also include a structure of more than 1 layer, in which is not limited to a specific implementation, the base portion 4302 may be disposed at a focal plane position corresponding to the lens portion 4301 in a more preferred case, this ensures that the detection pixel unit can obtain accurate return light information to the maximum, in which case the lens of the lens portion 4301 can construct an optical channel so that the signal received by the photosensitive portion of the detection unit is located near the corresponding focal position, and the detection unit base portion 4302 includes a photosensitive pixel array arranged in an array form, where, in order to meet the detection requirement of non-continuity, the diode of the photosensitive pixel unit may be a single photon avalanche diode array (SPAD) with single photon sensitivity, or an array type detector composed of photon counting type detection pixel units with linear amplification factor, or the like, which may also be a geiger type detector unit array APD. The direct output signal in the detector array is a photon counting sequence, so that the direct output and transmission of the digital signal are realized, the preset rule operation module takes the driving signal as a female parent to obtain a modulation sequence Y, which is also a discontinuous sequence signal, even the digital modulation sequence Y is directly obtained, and the digital modulation sequence Y are not similar analog signals in the prior art, so that the correlation operation is directly carried out in the preset rule operation module without A/D analog-to-digital conversion.

In the exemplary illustration of the chirp signal generator, on the one hand, the chirp signal generator generates a chirp signal as the modulation sequence Y, where the modulation sequence may be discretized as described above for the continuous signal in the example, and finally converted into a digital type modulation sequence signal, where the period of laser emission is selected as the chirp signal period T (i.e. the total duration in the segment of the emitted laser is selected as the period characteristic of the chirp signal), and the otherIn aspects, the chirp signal generator controls the laser modulation driving circuit to generate a pulse laser driving signal, the pulse laser driving signal controls the pulse laser to emit a laser pulse sequence, and the emission optical system projects the laser pulse sequence to a target area; the receiving system includes a receiving optical system, a photoelectric detector, a digital correlator, a digital integral accumulator, etc., where the receiving optical system focuses the laser pulse sequence reflected by the target to the photoelectric detector, the photoelectric detector starts detecting when the laser pulse sequence is emitted, and obtains a photon counting result in a laser pulse sequence emission period, in order to ensure that the calculation amount of the subsequent calculation result is smaller, first, the scene in the field is irradiated by the pulse sequence emitted by L times (where L is an integer greater than or equal to 1), more optimally, in order to obtain a more accurate detection result, an order of hundreds of thousands of values is selected, etc., and is not limited herein, and in order to ensure the accuracy of the data or the effect of operation accuracy and rapidness, etc., the receiving optical system is not limited herein, and statistics is obtained for all detection results of the L times, where statistics results obtained by using excitation information of less than or equal to L times of return light are counted, and photon counting results X are generated, for example, the scene is an exemplary structure in which is counted and the number of times X is generated by the following statistics, and the number of times M is equal to or less than 1, and the number M is an integer (M is equal to or equal to 1) and the number M is equal to or less than or equal to positive pulse accumulating result is equal to positive (M is equal to 1) and M is equal to or less than or equal to M is equal to 1, and M is equal to positive pulse accumulating number (M is equal to 1) is equal to or equal to M, and M is equal to positive pulse accumulation result is equal to or equal to M is equal to positive pulse M is equal to M _di The basic count sequence X consisting of M probe pulse count results is thus obtained as:

the L times of accumulation detection are firstly carried out to obtain a basic counting sequence X (X is L X) _d Accumulated of (a) and then multiplying X by Y to obtainTo Z (Z is L Z) _d Is added up) and then Z is added up in segments to obtain S.

The above steps can be represented in principle as the scheme of fig. 5, where the laser sequence of single shot is the top schematic case, each shot contains M detection pulses, the laser source outputs L pulse laser sequences in L times, and the detection module obtains trigger information of return light of the detection light emitted for not more than L times to obtain a statistical photon counting sequence, as shown in equation 9, and the finally constructed statistical photon counting sequence is the result as shown in the bottom schematic case of fig. 5.

The preset operation module can comprise a structure as shown in fig. 6, and comprises a digital multiplier unit and a digital integration and accumulation unit, the self-adaption of the scene in the detection view field can be realized through the multiplier unit and the digital integration and accumulation unit contained in the preset operation module, the self-adaption of the detection maximum distance can be adaptively adjusted along with the change of the scene to realize the self-adaption of the detection precision and the like, and the correlation operation between signals can be realized through the multiplier unit to further improve the anti-interference capability of the system. That is, the foregoing statistical photon counting sequence X of the return light obtained by the L times of pulse light emission can be obtained according to an exemplary scheme, and fig. 7 is a schematic diagram of a discrete modulation sequence Y generated by using a driving signal with a function expression f (X), and the discrete modulation sequence Y similar to the driving emission laser pulse is obtained by using the discretization scheme, wherein the single emission laser sequence includes M pulse laser excitation high value units, and the modulation sequence also includes N pulse high value units. The modulation signal is a discontinuous modulation sequence generated by the driving signal generating part according to the emission light pulse sequence similarity rule, and the result is shown in the following formula 10.

Y{y _i |y _i ＝f(i)i＝1，2，...，N} (10)

After obtaining the statistical photon counting sequence and the modulation sequence excited by the return of the emitted light, the preset rule operation module can perform related operation on the two groups of sequences according to the units in the module, thereby obtaining two groups of sequencesThe correlation results of the columns are shown in FIGS. 8 and 9, respectively, for two different schemes, according to the operation scheme of FIG. 8, the multiplication of the counted photon counting sequence with the modulation sequence can be performed, i.e. the modulation counting sequence Z can be obtained by means of a digital multiplier _d ：

Z _d ＝{z _di |z _di ＝x _di ·y _i ,i＝1,2,...,N} (11)

After the calculation of the multiplication unit is completed, the digital integration accumulator can perform the sectional accumulation of the modulation counting sequence, wherein the accumulation interval is an interval segment for performing the accumulation operation, the processing module can set the actual size of the accumulation interval according to a certain rule, and perform the sectional accumulation of the multiplication result sequence in the effective accumulation area in the accumulation interval, so as to obtain the enhancement effect of the signal, and ensure the detection accuracy, wherein the number of the accumulation units in the effective accumulation area is K, thus the final sectional accumulation counting sequence S is obtained after the sectional accumulation operation is performed _d ：

And finally, accumulating L sectional accumulated counting sequences obtained in L (L is a positive integer and L is more than or equal to d) laser pulse sequence transmitting periods by using a digital integral accumulator to obtain an accumulated counting sequence S:

Of course, fig. 9 is another implementation idea, referring to the drawing, we can obtain another scheme implemented by a correlation operation module, where each unit in the module performs a segment accumulation operation on a sequence first, that is, the statistical photon counting sequence X and the modulation sequence Y described above are first divided into an effective superposition interval in the accumulation interval, and then perform a segment accumulation operation on the two effective superposition intervals, and after completion, perform a multiplication operation on the two effective superposition intervals, where the operation results generated by the two sequences may be different, but not limited herein, both may include result correlation information associated with physical characteristics of a detected object distance, speed, and so on, the signal processing system includes time-frequency domain conversion, threshold detection, and information calculation, where the time-frequency domain conversion implements conversion calculation on a spectrum of the accumulation counting sequence S according to, for example, a wavelet operation, a segment FFT, FFT, chirp-Z operation, DFT, and so on, the threshold detection implements detection on a spectrum peak characteristic of the accumulation counting sequence S, including highest peak information, next highest peak information, peak information in a region of interest, and so on, and the information solution obtains information of a target relative distance, a relative speed, a three-dimensional image, and so on according to the spectrum information of the accumulation counting sequence S.

FIG. 10 can also be interpreted as a detailed description of another embodiment of the present invention, and is also an embodiment of the present invention, in which the laser source emits L pulse sequences for outputting, the reflected probe laser light from the object to be detected in the field of view forms a photon counting result X of the returned light, which can be L returned results, the modulation sequence can obtain a modulated counting sequence Z according to each output modulation sequence and multiplication operation with each returned photon counting sequence, and the final segmentation and accumulation result is finally performed to obtain a final counting sequence S _d ，

X _d ＝{x _di |i＝1，2，...，N} (14)

A discontinuous modulation sequence Y is obtained analogously to the previous scheme and then let X _d Multiplying by Y to obtain Z _d ，

Z _d ＝{z _di |z _di ＝x _di ·y _i ，i＝1，2，...，N} (15)

Then to Z _d Performing sectional accumulation to obtain S _d Similar to the piecewise accumulation scheme shown in equation 13, of course, only one illustrative case is schematically illustrated herein, and the actual implementation is not limited in this manner. This solution may require a greater computational effort than before, and requires a more optimal solution to achieve probing with fast output requirements, which is not limiting here.

The photon counting sequence or the accumulated photon counting sequence in the embodiment can be generated not only by the laser pulse sequence received by the photoelectric detector array, but also by the ambient background light, including natural background light and unnatural background light, received by the photoelectric detector array. Photon counting results generated by ambient background light, reasons of the detector array and the like can reduce the signal to noise ratio of the detection system, so that the detection performance is deteriorated.

Since natural background light, such as sunlight, and the like, and counting results generated by the detector array itself generally obey a certain statistical rule, the statistical rule can be determined according to a photon counting sequence or an accumulated photon counting sequence; on the other hand, since the generation rule of the laser pulse sequence and the photon counting rule generated by the laser pulse sequence are known, the photon counting statistical rule generated by unnatural background light interference, such as interference light of other detection equipment, and the like, can be distinguished from the photon counting sequence or accumulated photon counting sequence; according to the ambient background light and photon counting statistics rules generated by the detector array, the photon counting sequence or accumulated photon counting sequence generated by the photoelectric detector array can be corrected, so that the signal-to-noise ratio and the detection performance of the detection system are improved.

To suppress the above problem, in some embodiments, a count sequence generating module is added to the receiving system, which is used to obtain the photon count sequence, or accumulate the statistical characteristics of the photon count sequence, and generate an adaptive count sequence or accumulate the adaptive count sequence according to a preset rule.

FIG. 11 is a schematic diagram of a three-dimensional imaging system according to an embodiment of the present application; fig. 11 is a block diagram of a count sequence generation module compared with fig. 3, and the functions of other blocks are the same as those shown in fig. 3, and will not be described again here. In fig. 11, the counting sequence generating module generates an adaptive counting sequence according to the photon counting sequence statistics and the preset rules.

Fig. 12 is a flowchart of a generating adaptive counting sequence according to an embodiment of the present application. In some embodiments, the counting sequence generation module obtains natural background light, such as sunlight, and counting results generated by the detector array itself according to the photon counting sequence, and generates an adaptive counting sequence according to the natural background light, such as sunlight, and the counting results. The adaptive counting sequence module is used for counting the photons according to the photon counting sequence

X _d ＝{x _di |i＝1,2,...,N} (16)

For X described in equation 16 _d And (3) summing to obtain:

or for X shown in equation 16 _d Averaging to obtain:

the formulas (16) and (17) are for obtaining the characteristics of the photon counting sequence, and the summation of the formulas (16) and the averaging of the formulas (17) are for illustration, and are not limited in particular herein. Constructing an adaptive correction sequence conforming to a certain distribution according to the characteristics of the photon counting sequence, e.g. constructing an adaptive correction sequence X with a mathematical distribution such as a poisson distribution or a Gaussian distribution with a binomial distribution _dm The specific mathematical distribution is not limited herein. Adaptive correction sequence X _dm Variance and mean of photon counting sequence X _d Sum A _d Or arithmetic mean valueThe characteristics are in some specific relation, such as positive correlation or negative correlation, or some specific values, and are not specifically limited herein. Counting photons in sequence X _d And adaptive correction sequence X _dm ＝{x _dmi I=1, 2,..n } operates according to a prescribed preset rule, thereby changing the photon counting sequence X _d The number of high-value elements in the sequence X is obtained _da . For example, the operation may be performed according to a preset rule of formula (19):

the preset rule of formula (19) corresponds to the sequence X to be adaptively modified _dm Inserted into photon counting sequence X _d Obtaining an adaptive counting sequence X _da . Obtaining X _da The subsequent signal processing procedure of (a) is the same as that of the previous embodiment, and will not be described again.

Fig. 13 is a flowchart of a generating adaptive accumulation count sequence according to an embodiment of the present application. In fig. 13, the counting sequence generating module generates an adaptive accumulated counting sequence according to the accumulated photon counting sequence statistics and a preset rule.

In some embodiments, the counting sequence generation module obtains natural background light, such as sunlight, and counting results generated by the detector array itself according to the photon counting sequence, and generates an adaptive counting sequence according to the natural background light, such as sunlight, and the counting results. In a specific mode, the adaptive counting sequence module is used for counting the sequence according to accumulated photons

Summing the sequences of equation (20):

or by averaging the sequences described in equation 20:

The formulas (21) and (22) are to obtain the characteristic of the accumulated photon counting sequence, and the summation of the formulas (21) and the averaging of the formulas (22) are for illustration, and are not particularly limited herein. Constructing a modified sequence conforming to a certain distribution according to the characteristics of the photon counting sequence, e.g. constructing an adaptive modified sequence X with a binomial distribution such as a poisson distribution or a Gaussian distribution _m The specific mathematical distribution is not limited herein. Adaptive correction sequence X _m Sum of variance and mean of (a) and accumulated photon counting sequence X a or arithmetic meanThe characteristics are in some specific relation, such as positive correlation or negative correlation, or some specific values, and are not specifically limited herein. The accumulated photon counting sequence X and the adaptive correction sequence X _m ＝{x _mi I=1, 2, N } operates according to a prescribed preset rule, thereby changing the number of high-value elements in the accumulated photon counting sequence X to obtain an adaptive accumulated counting sequence X _a . For example according to a preset rule of formula (23),

X _a ＝{x _ai |x _ai ＝x _i +x _mi ,i＝1,2,...,N} (23)

the preset rule of the formula (23) is equivalent to adding the adaptive correction sequence and the accumulated photon counting sequence X to obtain the adaptive accumulated photon counting sequence X _a 。

In other embodiments, the variance of the shown series of formulas (20) through (22) and (20) may be calculated from:

equal characteristic obtaining threshold X _H Obtaining a threshold value X _H For example, the threshold value can be madeWherein: lambda is a positive integer, not specifically limited hereinAnd (5) setting. Screening out the value in the accumulated photon counting sequence X larger than the threshold value X _H The high value elements generated by the unnatural background light interference are resolved and removed by analyzing the distribution characteristics of the high value elements and combining the known emission frequency characteristics of the laser pulse sequence to obtain the self-adaptive accumulation counting sequence X _a 。

The adaptive accumulation counting sequence can be obtained by operation according to a preset rule in the formula (25):

obtaining an adaptive accumulation counting sequence X _a The subsequent processing is the same as in the previous embodiment and will not be described again here.

The generation of the adaptive counting sequence in real time in the above embodiment enhances the anti-interference effect, but also participates in the difficulty of implementing the imaging system.

Fig. 14 is a flowchart of yet another adaptive counting sequence for generating an adaptive count according to an embodiment of the present application. In other embodiments, the counting sequence generating module may also generate the adaptive correction sequence in advance according to priori information of counting statistics rules generated by factors such as natural background light interference (e.g. sunlight, etc.), self-cause of the detector array, unnatural background light interference (e.g. interference light of other detection devices, etc.) and the like. In this implementation manner, the counting sequence generating module stores a pre-generated adaptive correction sequence, and does not dynamically generate the adaptive correction sequence in real time according to the photon counting sequence or the accumulated photon counting sequence, the flow of generating the adaptive counting sequence is shown in fig. 14, the flow of generating the adaptive accumulated counting sequence is shown in fig. 15, and the preset rules in fig. 14 and fig. 15 may be the same as the preset rules in the above embodiment, which will not be repeated here. The processing procedure for the signals is the same as that of the previous embodiment, and will not be described again here.

Fig. 16 is a schematic diagram of a detection system according to an embodiment of the present application. The difference between the embodiment shown in fig. 16 and the embodiment shown in fig. 3 is that a counting sequence copy splicing module is added between the photoelectric detector and the digital multiplier in the detection system, and other modules are the same as those in the embodiment shown in fig. 3 and will not be described again.

Fig. 17 is a schematic diagram of another detection system according to an embodiment of the present application. The embodiment shown in fig. 17 is different from the embodiment shown in fig. 11 in that a counting sequence copying and splicing module is added between the photoelectric detector and the counting sequence generating module in the detecting system, and other modules are the same as those of the embodiment shown in fig. 11 and will not be described again.

In the embodiment shown in fig. 16 and 17, the count sequence copy splice module copies the photon count sequence X _d Conversion to replication splice sequence X _c ：

X _c ＝{x _ci i＝1,2,...,N} (26)

The digital multiplier obtains a modulation count sequence Zd:

Z _d ＝{z _di z _di ＝x _ci ·y _i ,i＝1,2,...,N} (27)

the preset rule operation module is used for modulating the counting sequence Z _d Performing sectional accumulation to obtain a sectional accumulation counting sequence S _d ：

Wherein N is ₀ Is the integer with the value closest to N/M, K is the integer and(R _max is the maximum detectable distance).

The preset rule operation module accumulates L segmentation accumulated counting sequences obtained in the L laser pulse sequence transmitting process to obtain an accumulated counting sequence S:

In the embodiment shown in fig. 16 and 17, the count sequence copy splice module copies photon count sequence X by copying _d And compares it with a photon counting sequence X _d Splicing to obtain copy spliced sequence X _c . FIG. 18 is a schematic diagram of a resulting replication splice sequence according to an embodiment of the present application. In the embodiment shown in fig. 18, the emission period of the laser pulse sequences is equal to the chirp signal period T, but each laser pulse sequence consists of(M is a positive integer) laser pulses (each laser pulse sequence in FIG. 7 consists of M ₀ =m/2=4 laser pulses), i.e. only emits laser pulses during the first half period of the chirp signal, so that the photon counting sequence obtained by the photodetector when detecting the laser pulse sequence of the d (d is a positive integer and d is less than or equal to L) th time is X during the first half period of the chirp signal _d The number of elements is N ₀ ＝N/2：

At this time, photon counting sequence X _d All elements in (a) as a copy splice sequence X _c And replicates photon counting sequence X _d All elements in (a) as a copy splice sequence X _c The latter N/2 term of (2) to obtain a copy splice sequence X represented by the formula (26) _c The number of the elements is N. The embodiment shown in fig. 18 is for illustrative purposes only and is not limited to emitting laser pulses only in half a period, and laser pulses may be emitted in 1/3 period, 1/4 period …, resulting in a copy splice signal by the method of the embodiment shown in fig. 18.

FIG. 19 is a schematic diagram of another resulting replication splice sequence provided by an embodiment of the present application. The count sequence copy splice module described in the embodiment of fig. 16 and 17 can obtain a copy splice sequence from the embodiment of fig. 19. The implementation shown in FIG. 19In the example, the emission period of the laser pulse sequences is equal to the chirp signal period T, and each laser pulse sequence is defined by m=f _s T (M is a positive integer) laser pulses (each laser pulse sequence in FIG. 19 consists of M=4 laser pulses), and the photon counting sequence obtained by the photoelectric detector when detecting the (d is a positive integer and d is less than or equal to L) th laser pulse sequence is X _d The number of the elements is N. Replication photon counting sequence X _d The first N-N/2M (assuming N is divisible by 2m=8, n=64 shown in fig. 19) of these elements are combined with X _d The latter N-N/2M elements are overlapped; the latter N/2M elements are combined with X _d The first N/2M elements in the sequence are overlapped to obtain a copy spliced sequence X _c The element number is also N, namely:

in contrast, according to the methods of the embodiments shown in fig. 3 and 11, an accumulated count sequence S including M elements may be obtained using a laser pulse sequence including M pulses, whereas the number of elements may be greater than M using the methods of the embodiments shown in fig. 16 and 17. Since the target information is obtained by analyzing the spectral characteristics of the accumulated count sequence S, if the target information obtained by the solution of the accumulated count sequence S obtained by the method described in the embodiment of fig. 3 and 16 is substantially the same as the target information obtained by the solution of the accumulated count sequence S obtained by the method described in the embodiment of fig. 16 and 17, the total laser emission energy required will be smaller and the detection efficiency will be higher by the method described in the embodiment of fig. 16 and 17.

The method in the embodiment shown in fig. 19 may be repeatedly executed, based on the previous execution result, overlapping and splicing part of the elements in the previous result again to obtain a new sequence again, so that the ranging accuracy may be further improved, and the embodiment shown in fig. 19 is only for illustrative purposes and is not limited in particular.

Fig. 20 is a schematic waveform diagram of three-dimensional imaging according to an embodiment of the present application. Fig. 20 is a schematic waveform diagram of the embodiment of fig. 16 during three-dimensional imaging, and the schematic principle of the embodiment of fig. 17 is similar to that of the embodiment of fig. 17, and will not be repeated here. In the embodiment shown in fig. 16, the driving signal generating part generates two paths of signals, one path of signals controls the laser modulation driving circuit, and further controls the pulse laser to emit laser, and after the laser pulse sequence is shaped and expanded by the emission optical system, the laser pulse sequence is projected to the target area. The laser pulse sequence reflected by the target is focused on the photodetector after being filtered and shaped by the receiving optical system, and a schematic diagram of a partial waveform corresponding to one possible implementation is given in the embodiment shown in fig. 20. The emission period of the laser pulse emission sequence is T, and each period contains M=4 pulses. In the emission period of the d-th laser pulse sequence, the photoelectric detector starts to emit T after the first pulse of the laser pulse sequence _R Within the time, i.e. 0.ltoreq.t.ltoreq.T _R The first detection is carried out in a time period to obtain a photon counting sequence X of the first detection _d1 The number of the elements is K, if the maximum detectable distance of the laser three-dimensional imaging is R _max T is then _R ≥2R _max C (c is the speed of light in vacuum), in the first detection, the modulation sequence Y of the first detection ₁ The number of elements is also K, X _d1 And Y ₁ The corresponding elements in the first detection are multiplied to obtain a modulation count sequence Z _d1 Will Z _d1 Summing the elements in the obtained product to obtain S _d1 Taking the pulse sequence as a segment accumulation counting sequence S in a certain laser pulse sequence transmitting period _d Is the first element of (c).

T is not less than T and not more than T/M+T _R The second detection is carried out in a time period, and the photoelectric detector can still detect the photon counting sequence X of the second detection in the second detection process although no pulse is emitted _d2 The number of elements is K, and in the second detection, the modulation sequence Y ₂ The number of the elements is also K, X can be _d1 And X is _d2 Corresponding elements are added to obtain X _d2’ X is taken as _d2’ And Y is equal to ₂ In (a) and (b)Multiplying the corresponding elements to obtain a modulation count sequence Z in the second detection _d2 X may also be made _d2 ＝X _d1 X is taken as _d2 And Y is equal to ₂ Multiplying the corresponding elements of the second detection to obtain a modulation count sequence Z _d2 Will Z _d2 Summing the elements in the obtained product to obtain S _d2 Taking the pulse sequence as a segment accumulation counting sequence S in a certain laser pulse sequence transmitting period _d Is a second element of (c).

And the like, in the third, fifth and seventh detection, the detection is correspondingly performed according to the first detection step; in the fourth, sixth and eighth detection, the steps according to the second detection are correspondingly executed, which are not repeated here, and respectively obtain S _d A segment accumulated count sequence S obtained at the d-th laser pulse sequence period _d As shown in the bottom row of fig. 20. And finally, adding the corresponding units of L segmentation accumulated counting sequences in total, which are obtained by L laser pulse sequence periods, S1, S2, … and SL to obtain an accumulated counting sequence S, and resolving target information by analyzing the spectrum characteristics of the accumulated counting sequence S to further realize three-dimensional imaging.

In summary, the prior art mainly includes, in addition to the above-described incoherent chirp signal amplitude modulated continuous wave laser three-dimensional imaging technique (hereinafter referred to as technique 1), an incoherent sinusoidal/pulse amplitude modulated laser three-dimensional imaging technique (itof, hereinafter referred to as technique 2) and a pulse photon counting laser three-dimensional imaging technique (dtof, hereinafter referred to as technique 3), and compared with the above-described technique, the present invention has the following advantages:

(1) Compared with the technology 1, the invention uses the pulse laser to detect, avoids the problem of waste of laser emission energy in the A/D sampling interval in the technology 1, thereby greatly improving the energy utilization rate and reducing the average emission power of the laser;

(2) Compared with the technology 1, the invention does not adopt devices such as a broadband amplifier, a mixer, an A/D and the like in the receiving system, and avoids the problem that the devices limit the dynamic range of the received laser signals, thereby leading the receiving system of the invention to have larger dynamic receiving range;

(3) Compared with the technology 1, in the receiving system, the method uses the digitized chirp signal as a modulation sequence, and uses the digital multiplier to realize the sequence multiplication, thereby reducing the influence of the chirp signal frequency modulation linearity and frequency modulation flatness on the ranging performance;

(4) Compared with the technology 2, the invention adopts the chirp signal to carry out the related receiving, thus having the distance resolution and effectively avoiding the influence of multipath effect;

(5) Compared with the technology 2, the invention improves the light interference resistance by adopting the correlation receiving, fourier analysis and spectrum detection, so the distance measurement performance is less affected by the light interference, and the laser energy required under the same detection condition is smaller;

(6) Compared with the technology 2, the invention does not adopt A/D any more, and has larger dynamic receiving range;

(7) Compared with the technology 3, the invention needs to transmit an accumulated counting sequence instead of a photon counting sequence, thereby greatly reducing the data transmission quantity;

(8) Compared with the technology 3, the method extracts the target distance information from the frequency spectrum, and reduces the influence of pulse shape distortion on the ranging performance;

(9) Compared with the technology 3, the invention improves the light interference resistance due to adopting the correlation receiving, fourier analysis and spectrum detection, so the distance measurement performance is less influenced by light interference.

The invention utilizes multiple direct receptions to form a distance-amplitude spectrum (frequency domain), and uses the frequency domain to detect the threshold value, the frequency spectrum peak value to determine the flight time, and the frequency spectrum amplitude threshold value can be self-adaptively set in specific implementation; the frequency spectrum peak value can be accurately judged, the scheme is a digital framework structure type as a whole, and the accuracy can be ensured by more FFT points; on the premise of larger operand, the accuracy and precision of detection can be ensured, the method is introduced in a form of accumulated charges in the exposure time, the problem of background light interference is restrained from an algorithm level through FFT and related reception (FMCW related signals with zero mean value), the transmitting power is completely received in the aspect of energy utilization, the whole system and method for utilizing the energy with the highest efficiency solve the problems of methods in the existing scheme, and the method has wide application prospect and popularization value.

It should be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

The above description is only of the preferred embodiments of the present application and is not intended to limit the present application, but various modifications and variations can be made to the present application by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application. It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures. The above description is only of the preferred embodiments of the present application and is not intended to limit the present application, but various modifications and variations can be made to the present application by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. The laser radar detection system is characterized by comprising a driving signal generation part, wherein the driving signal generation part acts on a laser source through a laser modulation driving circuit, and the laser source receives the driving signal and drives and emits a pulse type detection laser sequence; an array type return light receiving module for receiving a return light signal reflected by the detected object in the field of view and generating a return signal; the counting sequence splicing module is used for obtaining a copying splicing signal according to the return signal, the processing module is used for generating a modulating signal according to the driving signal generated by the driving signal generating part and obtaining a signal related to the distance with the copying splicing signal according to a preset rule operation, and the processing module is used for outputting the distance information of the final detected object according to the signal related to the distance.

2. The lidar detection system of claim 1, wherein the laser light source emits the detection laser sequence in less than one detection period to obtain a return signal, and wherein the count sequence splicing module replicates the return signal of the detection laser sequence emitted in the less than one detection period and splices the return signal to obtain the replicated splice signal.

3. The lidar detection system of claim 1, wherein the laser light source emits a detection laser sequence in one detection period to obtain a return signal, and wherein the counting sequence splicing module replicates a portion of the elements of the return signal of the detection laser sequence emitted in the one detection period and operates with the return signal to obtain the replicated splice signal.

4. The lidar detection system of claim 1, wherein the counting sequence stitching module replicates a portion of the elements of the last copy stitching signal based on the last copy stitching signal and computes the same with the last copy stitching signal to obtain the copy stitching signal.

5. The lidar detection system of claim 1, further comprising a counting sequence generation module that generates an adaptive counting sequence based on the return signal.

6. A detection method for detecting distance by using the laser radar ranging system of claim 1, which is characterized by comprising a driving signal generating part, wherein the driving signal generating part acts on a laser source through a laser modulation driving circuit, and the laser source receives the driving signal and drives and emits a pulse type detection laser sequence; an array type return light receiving module for receiving a return light signal reflected by the detected object in the field of view and generating a return signal; the counting sequence splicing module is used for obtaining a copying splicing signal according to the return signal, the processing module is used for generating a modulating signal according to the driving signal generated by the driving signal generating part and obtaining a signal related to the distance with the copying splicing signal according to a preset rule operation, and the processing module is used for outputting the distance information of the final detected object according to the signal related to the distance.

7. The method according to claim 6, wherein the laser light source emits a detection laser sequence in less than one detection period to obtain a return signal, and the counting sequence splicing module duplicates the return signal of the detection laser sequence emitted in the less than one detection period, and splices the return signals to obtain the duplicated spliced signal.

8. The method according to claim 6, wherein the laser light source emits a detection laser sequence in one detection period to obtain a return signal, and the count sequence splicing module duplicates a part of elements in the return signal of the detection laser sequence emitted in the one detection period and calculates the duplicated splice signal with the return signal.

9. The lidar detection method of claim 6, wherein the counting sequence stitching module replicates a portion of the elements of the last copy stitching signal based on the last copy stitching signal and computes the same with the last copy stitching signal to obtain the copy stitching signal.

10. The lidar detection method of claim 6, further comprising a counting sequence generation module that generates an adaptive counting sequence based on the return signal.