Striped tube laser radar wide light beam high speed rate laser ranging method and ranging system

Abstract

The present application relates to a streak tube laser radar wide beam high speed rate laser ranging method and ranging system; solve the problem that the existing STIL system needs to ensure high precision, the imaging frequency is high, the time is long, the imaging speed is low, the amount of data to be processed is large, which limits the application of STIL and the inaccurate reconstruction result caused by beam jitter; the method converts the laser emitted by the picosecond pulse laser into a wide beam to scan the target object for the first time, then reconstructs to obtain the echo distance, then adjusts the scanning area and the current scanning area and the last scanning area exist partially overlap, again collect, reconstruct to obtain the echo distance, through the echo distance error of the overlap area measured by the front and back two times, calculate and record the echo distance after eliminating the beam drift, repeat several times, until the whole distance information of the target object surface is obtained; the present application also proposes a system based on the above method.

Description

TECHNICAL FIELD

[0001] The present application relates to a laser measuring system, in particular to a stripe tube laser radar wide beam high speed laser ranging method and ranging system. BACKGROUND

[0002] The stripe tube laser radar is a kind of laser radar system using stripe tube detector as a core component for scanning imaging, which mainly includes a pulsed laser, an optical transmitting unit, a scanning unit, a synchronous control unit, an optical receiving unit, a collection and target reconstruction unit. The stripe tube laser radar system has the characteristics of high resolution, large field of view and strong anti-interference capability, and is widely used in target range measurement, ocean exploration, ultrafast diagnosis and many other fields.

[0003] The existing STIL (stripe tube imaging laser radar) realizes imaging of a target object by emitting a horizontal line laser and then scanning in the vertical direction. Each scanning completes one imaging. In order to ensure high imaging accuracy, the scanning of the line laser needs to be very dense, which results in a large number of imaging times and a lot of time spent. Moreover, a large number of line laser scanning times not only reduces the imaging speed but also increases the amount of data to be processed subsequently, greatly limiting the wide application of STIL.

[0004] Moreover, the STIL system uses a pulsed laser. The pulsed laser has very small beam jitter (ns level) (beam jitter refers to that the pulsed laser has a random jitter length time delay before emitting a laser pulse after receiving the pulse signal of the controller). In general laser active imaging systems, this error can be ignored. However, since the stripe tube detector has very high measurement accuracy, the influence of beam jitter cannot be ignored. The reason for the error caused by beam jitter is that the signal emitted by the signal generator is equal time interval during the collection process, so each time the data is reconstructed, it is also considered to be equal interval. However, beam jitter causes the actual time interval of each frame of image actually collected to be different. Beam jitter causes the time interval between each frame of image to change, thus causing the relative distance of each row on the target object reconstructed to change, and the result of reconstruction is inaccurate. SUMMARY

[0005] The present application aims to solve the problems of the existing STIL system, i.e. in order to ensure high imaging accuracy, a large number of imaging times are needed, a lot of time is spent, the imaging speed is reduced, and the amount of data to be processed subsequently is increased, greatly limiting the application of STIL, and the reconstruction result is inaccurate due to beam jitter. The present application provides a stripe tube laser radar wide beam high speed laser ranging method and ranging system.

[0006] The technical scheme of the present application is as follows:

[0007] The application discloses a wide-beam high-speed laser ranging method for a streak tube laser radar.

[0008] Step 1: a picosecond pulse laser is diffracted, beam-shaped and width-adjusted to generate a wide beam, which is scanned into a scanning area on the surface of a target object;

[0009] Step 2: echo signals of the target object are collected, echo distances D1 are obtained and recorded through reconstruction;

[0010] Step 3: the scanning area is adjusted along the vertical direction, the current scanning area partially overlaps the last scanning area, echo signals of the target object are collected again, echo distances D21 of the overlapping area and echo distances D221,..., D22 l ,..., D22 M of M non-overlapping areas are obtained through reconstruction; if the scanning area is a plane, D1=D21=D221=...=D22 l =...=D22 M are recorded, and step 5 is performed; if the scanning area is a stepped structure, step 4 is performed; wherein 1<=l<=M, and M represents the number of steps in the scanning area;

[0011] Step 4: echo distances Q21 of the overlapping area and echo distances Q22 l of all non-overlapping areas of the target object after elimination of beam drift are calculated and recorded through the second collection of echo signals; wherein Q21=D1; Q22 l =D22 l -(D21-D1);

[0012] Step 5: the scanning area is adjusted again along the vertical direction, the current scanning area partially overlaps the last scanning area, echo signals of the target object are collected again, echo distances D31 of the overlapping area and echo distances D321,..., D32 j ,..., D32 E of E non-overlapping areas are obtained through reconstruction; if the scanning area is a plane, D22 M =D31=D321=...=D32 j =...=D32 E or

[0013] Q22 M =D31=D321=...=D32 j =...=D32 E are recorded, and step 7 is performed; if the scanning area is a stepped structure, step 6 is performed; wherein 1<=j<=E, and E represents the number of steps in the scanning area;

[0014] Step 6: calculate and record the echo distance Q31 of the coincident area after the target echo signal is eliminated of the third time collected and the echo distance Q32 of all non-coincident areas after the light beam drift is eliminated j , and perform step 7; wherein Q31=D22 M or Q31=Q22 M ; Q32 j =D32 j -(D31-D22 M ) or Q32 j =D32 j -(D31-Q22 M );

[0015] Step 7: complete W times of scanning of the target by using the same method as steps 5-6; it is required that the target surface is completely covered after W times of scanning;

[0016] Step 8: obtain all distance information of the target surface based on the recorded echo distances in steps 3-7.

[0017] Further, in step 1, the width adjustment is performed by a Powell prism or a cylindrical lens.

[0018] Further, in step 1, the echo signal is collected by a single-slit streak tube.

[0019] The present application also provides a streak tube laser radar wide light beam high-speed laser ranging system for implementing the above-mentioned streak tube laser radar wide light beam high-speed laser ranging method; the special features of which are:

[0020] The streak tube laser radar wide light beam high-speed laser ranging system comprises a picosecond pulse laser, a beam shaping element module, a scanning mirror, a control unit, a receiving unit, a single-slit streak tube and a data processing unit;

[0021] The picosecond pulse laser is used to emit picosecond pulse laser, the beam shaping module and the scanning mirror are sequentially arranged along the emission light path of the picosecond pulse laser, the target is arranged on the emission light path of the scanning mirror, the receiving unit and the single-slit streak tube are arranged on the echo light path of the target; the data processing unit is electrically connected with the single-slit streak tube;

[0022] The data processing unit is electrically connected with the input end of the control unit, and the output end of the control unit is electrically connected with the picosecond pulse laser, the single-slit streak tube and the scanning mirror; the control unit is used to send a trigger signal to the picosecond pulse laser, the single-slit streak tube and the scanning mirror;

[0023] The laser emitted by the picosecond pulse laser passes through a beam shaping module to be diffracted and beam shaped, and the width of the laser is adjusted, and then a wide beam is formed and emitted to a scanning mirror, the scanning mirror scans a target object, the echo light path of the target object passes through a receiving unit and is collected by a single-slit streak tube, the single-slit streak tube processes the collected echo light path, generates a streak image, and sends the streak image to a data processing unit, the data processing unit receives the streak image and processes the streak image, and outputs an echo distance and / or an echo distance after eliminating beam drift, and then a control unit controls the scanning mirror to be deflected by a fixed angle, and the single-slit streak tube collects the echo light path again for processing.

[0024] Further, the beam shaping module comprises a diffractive optical element, a beam shaping element and a Powell prism arranged in sequence along the light path of the picosecond pulse laser.

[0025] The diffractive optical element is used to convert the Gaussian beam emitted by the picosecond pulse laser into a square flat-top beam, the beam shaping element is used to reduce the divergence angle of the square flat-top beam to convert it into an approximately parallel beam, and the Powell prism is used to convert the square parallel beam into a long rectangular wide beam emitted to the scanning mirror, the length of the long rectangular wide beam is greater than the side length of the square parallel beam, and the width of the long rectangular wide beam is equal to the side length of the square parallel beam.

[0026] Further, a reflecting mirror is arranged on the light path of the Powell prism, the reflecting mirror is used to change the direction of the light path of the Powell prism, and the scanning mirror is located on the light path of the reflecting mirror.

[0027] Further, the picosecond pulse laser is a 532nm picosecond pulse laser.

[0028] Further, the control unit is a signal generator.

[0029] Further, the beam shaping element is a telescope system comprising two lenses.

[0030] Compared with the prior art, the beneficial effects of the present application are as follows:

[0031] 1. In the present application, the target object is scanned by a wide beam, the wide beam imaging increases the width of the scanning laser, reduces the scanning times, and through the extraction of multi-echo data, the imaging speed of the streak tube laser radar is improved under the premise of ensuring the imaging accuracy, and the imaging speed of the wide beam laser active imaging is very fast, so that the STIL system can complete the measurement in a short time, and the problem of slow imaging speed of the existing STIL is solved.

[0032] 2. In the present application, the effects of laser beam drift are compensated by wide-beam lamination imaging through laminated scanning, and the imaging accuracy of the streak tube laser radar is improved, so that the STIL system can measure the distance accuracy of 10 -5 m order of magnitude of fine objects. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 is a schematic diagram of a wide-beam laser ranging system of a streak tube laser radar embodiment of the present application;

[0034] Figure 2 is a schematic diagram of a target structure in the embodiment of the present application;

[0035] Figure 3(a) is a schematic diagram of the kth scanning area in the embodiment of the present application;

[0036] Figure 3(b) is a schematic diagram of the k+1th scanning area in the embodiment of the present application;

[0037] Figure 3(c) is a schematic diagram of the kth and k+1th scanning laser overlap area in the embodiment of the present application;

[0038] Figure 4(a) is a laser intensity distribution diagram of the kth scanning imaging in the embodiment of the present application, wherein the abscissa represents the height value of the target when the kth detection is performed, and the ordinate represents the intensity of the target echo signal when the kth detection is performed;

[0039] Figure 4(b) is a laser intensity distribution diagram of the k+1th scanning imaging in the embodiment of the present application, wherein the abscissa represents the height value of the target when the k+1th detection is performed, and the ordinate represents the intensity of the target echo signal when the k+1th detection is performed;

[0040] In the figure, 1 is a picosecond pulse laser; 2 is a diffractive optical element; 3 is a beam shaping element; 4 is a Powell prism; 5 is a reflecting mirror; 6 is a scanning mirror; 7 is a signal generator; 8 is a receiving optical lens; 9 is a streak tube; 10 is a data processing unit;

[0041] A-kth scanning laser illumination area; B-k+1th scanning laser illumination area; C-kth and k+1th scanning laser overlap area. DETAILED DESCRIPTION

[0042] The streak tube 9 is divided into a multi-slit streak tube and a single-slit streak tube, the multi-slit streak tube can flash imaging but the precision is not as good as the single-slit streak tube, and the single-slit streak tube 9 is adopted as the detector of the laser radar in the application. When the laser echo signal reaches the single-slit streak tube 9, the laser echo signal first passes through the slit in front of the streak tube 9 and then is incident on the photocathode of the streak tube 9, the incident photons are photoelectrically converted into electrons, when the electrons enter the deflection electrode, a deflection voltage with linear variation over time is added to the deflection electrode, the electrons entering the deflection electrode at different moments are subjected to different deflection voltages, thereby different deflection angles are generated, and then the different deflection angles are hit on different positions on the fluorescent screen, the different deflection distances on the fluorescent screen are recorded by the CCD, and the flight time information of the echo photons is converted into the position information on the two-dimensional image, but this process only completes the collection of one frame of streak image, and multiple frames of target object streak images can be obtained through the line-by-line scanning of the laser.

[0043] Each frame of streak image represents a row of distance information on the target object, the distance information contained in each frame of streak image is solved through an algorithm, and then multiple frames of distance information are spliced to obtain the complete three-dimensional information of the target object, based on the imaging principle, the STIL has a very high time resolution, which can reach picoseconds or even sub-picoseconds.

[0044] Based on the above content, the application provides a streak tube laser radar wide-beam high-speed laser ranging system, as shown in the figure, which comprises a picosecond pulse laser 1, a beam shaping module, a scanning mirror 6, a control unit, a receiving unit, a reflecting mirror 5, a single-slit streak tube 9 and a data processing unit 10. Figure 1 The beam shaping module comprises a diffractive optical element 2, a beam shaping element 3 and a Powell prism 4, the control unit is a signal generator 7, and the data processing unit 10 adopts a computer; the beam shaping element 3 is a telescope system composed of two lenses; the picosecond pulse laser 1 adopts a 532nm picosecond pulse laser, and the receiving unit is a receiving optical lens 8.

[0045] The picosecond pulse laser 1 is used for emitting picosecond pulse laser, the diffractive optical element 2, the telescope system, the Powell prism 4, the reflecting mirror 5 and the scanning mirror 6 are sequentially arranged along the laser emission light path, the target object is arranged on the emission light path of the scanning mirror 6, the receiving optical lens 8 and the single-slit streak tube 9 are sequentially arranged on the reflected light path of the target object, the data processing unit 10 is electrically connected with the single-slit streak tube 9, the data processing unit 10 is electrically connected with the signal generator 7, and the signal generator 7 is electrically connected with the picosecond pulse laser 1, the single-slit streak tube 9 and the scanning mirror 6.

[0046] The functions of the components are as follows:

[0047] The diffractive optical element 2 is used for converting the received laser from a Gaussian beam into a square flat-top beam, the telescope system is used for shaping the square flat-top beam with a certain divergence angle into a parallel light beam, the Powell prism 4 is used for reshaping the exiting parallel light beam, and a long rectangular laser beam with a certain width is obtained, which is long in the horizontal direction and narrow in the vertical direction (scanning direction), the mirror 5 is used for changing the direction of the light path of the Powell prism 4, the receiving optical lens 8 is used for receiving the echo light path (reflected light path, that is, echo signal) of the target object, the single-slit streak tube 9 is used for collecting the echo light path emitted by the receiving optical lens 8, and after the collected echo light path is converted into a streak image by the single-slit streak tube 9, the streak image is sent to the data processing unit 10 for processing to obtain the echo distance and the echo distance after the beam drift is eliminated through calculation.

[0048] The working principle of the wide-beam high-speed laser ranging system of the streak tube laser radar provided in the application is as follows:

[0049] The signal generator 7 sends a trigger signal to the picosecond pulse laser 1, the single-slit streak tube 9 and the scanning mirror 6, and after receiving the trigger signal, the picosecond pulse laser 1, the single-slit streak tube 9 and the scanning mirror 6 are started, the picosecond pulse laser 1 emits a pulse laser, the pulse laser is converted into a square flat-top beam by the diffractive optical element 2, and after being shaped by the beam shaping element 3 composed of the telescope system, a square parallel light beam is formed and emitted, and then the square parallel light beam is reshaped by the Powell prism 4, the long rectangular wide-beam emitted after being shaped by the Powell prism 4 is folded by the mirror 5 and then enters the scanning mirror 6, and after being reflected by the scanning mirror 6, the long rectangular wide-beam reaches the target object.

[0050] After the laser reaches the target object, the laser is reflected to generate an echo light path, the echo light path is received by the receiving optical lens 8, the echo signal is collected by the single-slit streak tube 9, and after the collected echo signal is converted into a streak image by the single-slit streak tube 9, the streak image is sent to the data processing unit 10 for processing.

[0051] After the collection is completed, the signal generator 7 sends a trigger signal to the scanning mirror 6 again, the trigger signal makes the scanning mirror 6 deflect along the vertical direction once, and at the same time, the picosecond pulse laser 1 emits a laser pulse again to start the next collection and imaging process.

[0052] In order to suppress the beam drift in the STIL wide beam imaging process, the application proposes a wide beam superposition irradiation method, by controlling the scanning angle of the scanning mirror 6 in the vertical direction each time, the region of the target object scanned by the wide beam laser each time and the region illuminated by the previous scanning are overlapped in the scanning direction (vertical direction), when reconstructing the multi-frame fringe pattern, the distance information obtained by the previous scanning in the overlapping part is set as the initial distance information of the next scanning, through such iterative setting, it can be ensured that the time interval of each frame image is the same during reconstruction, and through a small overlap percentage, the speed advantage of wide beam imaging can be ensured while eliminating the influence of beam drift.

[0053] When using wide beam STIL for scanning imaging, one pulse laser may hit two or more different distance target objects in the vertical direction at the same time in one imaging, so that two or more echo light paths will be generated at the same time in the fringe pattern, based on the above beam drift suppression method, the application proposes a wide beam laser ranging system of the streak tube laser radar, as shown in the figure, taking a double-step ladder-shaped target object as an example, assuming that the height of the upper step of the ladder-shaped target object (i.e. the distance from the upper step of the target object to the streak tube 9) is L, and the height of the lower step (i.e. the distance from the lower step of the target object to the streak tube 9) is H, the specific operation steps are as follows: Figure 2

[0054] Step 1: start

[0055] 1.1 The signal generator 7 sends a trigger signal to the picosecond pulse laser 1, the scanning mirror 6 and the single-slit streak tube 9, and starts the picosecond pulse laser 1, the scanning mirror 6 and the single-slit streak tube 9;

[0056] Step 2: first imaging measurement

[0057] 2.1 The picosecond pulse laser 1 emits laser, which passes through the diffractive optical element 2, the telescope system, the Powell prism 4, the reflecting mirror 5 and the scanning mirror 6 in turn and then is emitted to the target object surface, and forms an echo light path on the target object surface, which is received by the receiving optical lens 8 and sent to the single-slit streak tube 9;

[0058] 2.2 The single-slit streak tube 9 collects the echo light path entering its slit, generates a fringe pattern, and sends it to the data processing unit, and the data processing unit reconstructs to obtain the echo distance D1;

[0059] The calculation method of D1 is as follows:

[0060] The method for STIL data reconstruction to extract multi-echo data is based on waveform decomposition, which regards the echo signal as a sum of a series of signal functions and noise, and can be expressed as:

[0061] ​

[0062] in, For echo signal, For component functions, Let N be the noise level, N be the number of echo signals, and i represent the i-th echo signal. Since the laser emitted by STIL is a Gaussian beam, The echo signal follows a Gaussian distribution. It can be represented as:

[0063]

[0064] in, This represents the amplitude of the Gaussian component, which is also the intensity value of the i-th echo signal. This represents the center position of the Gaussian function, which is also the center position of the i-th echo signal. This represents the width of the Gaussian function, and also the width of the i-th echo signal;

[0065] To accurately reconstruct the center of the multi-echo signal, the fringe pattern first needs to be deblurred, followed by deconvolution using the system's point spread function (PSF). Then, a decision system is used to determine the number *i* of target echoes, and finally, the individual components are analyzed... The fitting obtained The value, through This allows us to extract the distance information of the data in a time channel, i.e., the echo distance. In this step, N = 1, μ1 = D1 = L;

[0066] Step 3: Second imaging. During the second measurement, the scanning area of ​​scanning mirror 6 is set to be located on the upper step.

[0067] 3.1 After the signal generator 7 sends a trigger signal to the scanning mirror 6, the scanning mirror 6 shifts in the vertical direction by an angle Q to form a new scanning area. The shift angle Q must satisfy the requirement that the current scanning area overlaps with the previous scanning area in a fixed area.

[0068] 3.2 The picosecond pulse laser 1 emits a laser beam, which passes sequentially through the diffractive optical element 2, the telescope system, the Powell prism 4, the reflector 5, and the scanning mirror 6 before being emitted onto the surface of the target object. An echo light path is formed on the surface of the target object, which is received by the receiving optical lens 8 and then sent to the single slit stripe tube 9.

[0069] 3.3 The single-slit streak tube 9 collects the laser beams that are incident to its slit, generates a streak image, and sends it to the data processing unit 10, which reconstructs the echo distance D21 of the overlapping region and the echo distance D22 of the non-overlapping region; because the second scanning region is located on the upper step and is in the same vertical plane as the first scanning region, D1=D21=D22=L, and D1=D21=D22=L is directly recorded;

[0070] Step 4: kth imaging, set the scanning region of the scanning mirror 6 during the kth measurement to be located on the upper step;

[0071] 4.1 After the signal generator 7 sends a trigger signal to the scanning mirror 6, the scanning mirror 6 continues to shift by Q degrees in the vertical direction, forming a new scanning region, as shown in Fig. 3(a); Figure 2 As shown in Fig. 3(a), assume that the kth laser illumination region is A, and A is located on the upper step of the step target; there is a fixed region of overlap between the current scanning region and the previous scanning region;

[0072] 4.2 The picosecond pulse laser 1 emits laser light, which passes through the diffractive optical element 2, the telescope system, the Powell prism 4, the mirror 5, and the scanning mirror 6 in turn and is emitted to the target surface, and forms a reflected light path on the target surface, which is received by the receiving optical lens 8 and then sent to the single-slit streak tube 9;

[0073] 4.3 The single-slit streak tube 9 collects the laser beams that are incident to its slit, generates a streak image, and sends it to the data processing unit 10, which reconstructs the echo distance D21 of the overlapping region and the echo distance D22 of the non-overlapping region; because the second scanning region is located on the upper step and is in the same vertical plane as the first scanning region, D1=D21=D22=L, and D1=D21=D22=L is directly recorded;

[0074] Step 5: k+1th imaging, set the scanning region of the scanning mirror 6 during the k+1th measurement to cover the upper step and the lower step;

[0075] 5.1 After the signal generator 7 sends a trigger signal to the scanning mirror 6, the scanning mirror 6 continues to shift by Q degrees in the vertical direction, forming a new scanning region, as shown in Fig. 3(a); Figure 2 As shown in Fig. 3(b) and Fig. 3(c), assume that the k+1th laser illumination region is B, and B spans the upper step and the lower step; assume that the overlapping region is the C region in the k+1th imaging and the kth imaging, and C is located on the upper step;

[0076] 5.2 Picosecond pulsed laser 1 emits laser, laser passes through diffractive optical element 2, telescope system, Powell prism 4, mirror 5, scanning mirror 6 in turn, and then emits to the target surface, and forms a return light path on the target surface, is received by receiving optical lens 8, and is sent to single-slit streak tube 9;

[0077] 5.3 Single-slit streak tube 9 collects laser beams entering the slit thereof, generates a streak image, and sends the streak image to data processing unit 10, and data processing unit 10 obtains return distances D(k+1)1 of the overlapping region C and return distances D(k+1)2 of the non-overlapping region after reconstruction, and calculates return distances Q(k+1)1 and Q(k+1)2 after elimination of beam drift;

[0078] Specifically: in the k+1th imaging, one pulsed laser hits two different distances of the target in the vertical direction at the same time in one imaging, so that two returns are generated in the same time channel in the streak image, and the existing reconstruction process cannot process the multi-return condition as shown in FIG. 3 and FIG. 4(b), and can only detect one return signal as shown in FIG. 4(a) in the kth imaging, so that distance information extraction is completed through multi-return detection, two return signals are extracted through multi-return detection, and according to formula (2-2),

[0079]

[0080] Wherein N=2, when i=1, f1(x) represents the left peak in FIG. 4(b), and μ1 is obtained through fitting, μ1 represents the distance of the first return signal in the k+1th imaging, that is, the distance of the region C from the detector, μ1=D(k+1)1. When i=2, f2(x) represents the right peak in FIG. 4(b), and μ2 represents the distance of the second return signal in the k+1th imaging, that is, the distance of the lower layer step in the region B from the detector, μ2=D(k+1)2.

[0081] The kth irradiation region A is entirely located on the upper layer step of the target, at this time, the return distance of the target obtained through reconstruction of the kth scanning is L, the k+1th irradiation region B contains the upper layer step and the lower layer step, and in an ideal state, the return distance of the overlapping region C obtained through reconstruction is L, and the return distance of the non-overlapping region is H. However, due to the influence of beam drift, a random distance error R is introduced between the kth and the k+1th, so that the distance of the region B obtained through reconstruction is offset by the error R as a whole, the distance of the region C becomes L+R, and the distances of the remaining regions are H+R;

[0082] The present application utilizes the overlapping area C area of wide light beam when reconstructing, subtracts the echo distance of the kth time from the distance value of the common area C of the k+1th time, so that the distance error R can be obtained, and then subtracts R from the distance obtained by the k+1th scanning, so that the accurate distance of the k+1th imaging after eliminating the beam drift is obtained, that is, R=D(k+1)1-Dk2, Q(k+1)1=D(k+1)1-R=Dk2; Q(k+1)2=D(k+1)2-R;

[0083] The distance information obtained by the kth time and the k+1th time is combined, so that the distance of the target object in the two scans can be obtained;

[0084] Step 6: k+2th imaging, when the k+2th measurement is set, the scanning area of the scanning mirror 6 is located on the lower layer of the ladder;

[0085] 6.1 After the signal generator 7 sends a trigger signal to the scanning mirror 6, the scanning mirror 6 is offset by an angle Q in the vertical direction to form a new scanning area. The offset angle Q needs to satisfy that the present scanning area and the last scanning area have a fixed area of overlap, and the overlapping area is located on the lower layer of the ladder;

[0086] 6.2 The picosecond pulse laser 1 emits laser, which passes through the diffractive optical element 2, the telescope system, the Powell prism 4, the reflecting mirror 5, the scanning mirror 6 in turn, and then is emitted to the target object surface, and forms a return light path on the target object surface. After being received by the receiving optical lens 8, it is sent to the single-slit streak tube 9;

[0087] 6.3 The single-slit streak tube 9 collects the laser beam entering its slit, generates a streak pattern, and sends it to the data processing unit 10 to reconstruct the return distance D(k+2)1 of the overlapping area and the return distance D(k+2)2 of the non-overlapping area. Because the non-overlapping area of the k+2th scanning area and the k+1th scanning area is in the same vertical plane, D(k+2)1=D(k+2)2=Q(k+1)2 is directly recorded;

[0088] Step 7: The same method as steps 2-6 is used to complete W times scanning of the target object. After W times scanning, the target object surface is completely covered, the signal generator 7, the picosecond pulse laser 1, the scanning mirror 6 and the single-slit streak tube 9 are turned off, and the ranging is completed.

Claims

1. A streak tube lidar wide-beam high-rate laser ranging method, characterized in that, The method comprises the following steps: Step 1: a picosecond pulsed laser is diffracted, beam-shaped, and width-adjusted to generate a wide beam, which is scanned into a scanning area on the surface of a target object; Step 2: a return signal of the target object is collected, and a return distance D1 is obtained and recorded by reconstruction; Step 3: adjust the scanning area in the vertical direction, and the current scanning area partially overlaps with the last scanning area, secondly collect the echo signals of the target object, and reconstruct the echo distances D21 of the overlapping area and the echo distances D221, …, D22 of the M non-overlapping areas l , …, D22 M ; if the scanning area is a plane, record D1 = D21 = D221 = … = D22 l = … = D22 M , and perform step 5; if the scanning area is a stepped structure, perform step 4; wherein 1≤l≤M, and M represents the number of steps in the scanning area; Step 4: Calculate and record the echo distance of the coincident region after the second acquisition of the target echo signal eliminating the beam drift Q21 and the echo distance of all non-coincident regions Q22 l and perform step 5; wherein Q21 = D1; Q22 l =D22 l -(D21-D1); Step 5: Adjust the scanning area again in the vertical direction, and the current scanning area partially overlaps with the last scanning area, again collect the echo signals of the target object, and reconstruct the echo distances D31 of the overlapping area and the echo distances D321, …, D32 of the non-overlapping areas j , …, D32 E ; if the scanning area is a plane, record D22 M = D31 = D321 = … = D32 j = … = D32 E or Q22 M = D31= D321=... = D32 j =... = D32 E , and step 7 is performed; if the scanning region is a step structure, step 6 is performed; wherein 1≤j≤E, E represents the number of steps in the scanning region; Step 6: Calculate and record the echo distance of the coincident region after the target echo signal eliminates the beam drift of the third acquisition Q31 and the echo distance of all non-coincident regions Q32 j , and perform step 7; wherein Q31=D22 M or Q31=Q22 M ; Q32 j =D32 j -(D31-D22 M ) or Q32 j =D32 j -(D31-Q22 M ); Step 7: the same method as in steps 5-6 is used to complete W times of scanning of the target object; it is required that the target object surface is completely covered after W times of scanning; Step 8: based on the recorded return distances in steps 3-7, all distance information of the target object surface is obtained.

2. The wide-beam high-speed laser ranging method of the streak tube laser radar according to claim 1, characterized in that: In step 1, the width adjustment is performed by a Powell prism (4) or a cylindrical lens.

3. The wide-beam high-speed laser ranging method of the streak tube laser radar according to claim 1 or 2, characterized in that: In step 1, the return signal is collected by a single-slit streak tube (9).

4. A wide-beam high-speed laser ranging system of a streak tube laser radar, which is used to implement the wide-beam high-speed laser ranging method of the streak tube laser radar according to claim 1, characterized in that: It comprises a picosecond pulsed laser (1), a beam-shaping element module, a scanning mirror (6), a control unit, a receiving unit, a single-slit streak tube (9), and a data processing unit (10); The picosecond pulsed laser (1) is used to emit a picosecond pulsed laser, the beam-shaping module and the scanning mirror (6) are sequentially arranged along the emission light path of the picosecond pulsed laser (1), the target object is arranged on the emission light path of the scanning mirror (6), the receiving unit and the single-slit streak tube (9) are arranged on the return light path of the target object; the data processing unit (10) is electrically connected with the single-slit streak tube (9); The data processing unit (10) is electrically connected with the input end of the control unit, and the output end of the control unit is electrically connected with the picosecond pulsed laser (1), the single-slit streak tube (9), and the scanning mirror (6); the control unit is used to send a trigger signal to the picosecond pulsed laser (1), the single-slit streak tube (9), and the scanning mirror (6); The laser emitted by the picosecond pulsed laser (1) is diffracted, beam-shaped, and width-adjusted by the beam-shaping module to form a wide beam, which is emitted to the scanning mirror (6); the scanning mirror (6) scans the target object; the return light path of the target object passes through the receiving unit and is collected by the single-slit streak tube (9); the single-slit streak tube (9) processes the collected return light path to generate a fringe pattern, which is sent to the data processing unit (10); the data processing unit (10) receives and processes the fringe pattern to output a return distance after beam drift is eliminated; then the control unit controls the scanning mirror (6) to deflect by a fixed angle, and the single-slit streak tube (9) collects and processes the return light path again.

5. The wide-beam high-speed laser ranging system of the streak tube laser radar according to claim 4, characterized in that: The beam-shaping module comprises a diffractive optical element (2), a beam-shaping element (3), and a Powell prism (4), which are sequentially arranged along the emission light path of the picosecond pulsed laser (1). The diffraction optical element (2) is used to convert the Gaussian light beam emitted by the picosecond pulse laser (1) into a square flat-top light beam, the beam shaping element (3) is used to reduce the divergence angle of the square flat-top light beam to convert it into an approximately parallel light beam, and the Powell prism (4) is used to convert the square parallel light beam into a long rectangular wide light beam emitted to the scanning mirror (6), the length of the long rectangular wide light beam is greater than the side length of the square parallel light beam, and the width of the long rectangular wide light beam is equal to the side length of the square parallel light beam.

6. The streak tube laser radar wide light beam high speed laser ranging system according to claim 5, wherein: Further comprising a reflecting mirror (5) arranged on the light path of the Powell prism (4), the reflecting mirror (5) is used to change the direction of the light path of the Powell prism (4), and the scanning mirror (6) is located on the light path of the reflecting mirror (5).

7. The streak tube laser radar wide light beam high speed laser ranging system according to claim 5 or 6, wherein: The picosecond pulse laser (1) is a 532nm picosecond pulse laser.

8. The streak tube laser radar wide light beam high speed laser ranging system according to claim 7, wherein: The control unit is a signal generator (7).

9. The streak tube laser radar wide light beam high speed laser ranging system according to claim 8, wherein: The beam shaping element (3) is a telescope system including two lenses.

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