Moving target single-photon super-resolution imaging method

Abstract

The invention discloses a moving target single-photon super-resolution imaging method, and relates to the technical field of super-resolution imaging. According to the invention, a single-photon detection system and reflection tomography laser radar imaging are combined, and echo photon waveform recovery is used to replace a linear detection system to directly acquire echo waveform data. On the basis of stationary target single-photon detection and a traditional laser reflection chromatography technology, the characteristics of a moving target single-photon detection waveform are modeled, a moving target photon waveform recovery algorithm is designed, and research on photon waveform registration and a moving target image reconstruction method under a limited angle is carried out. And finally, single-photon super-resolution imaging of the moving target is realized.

Description

Technical Field

[0001] The present invention relates to the field of super-resolution imaging technology, and in particular to a single-photon super-resolution imaging method for moving targets. Background Art

[0002] Laser Reflective Tomography (LRT) imaging technology is a new type of laser imaging technology developed on the basis of Computed Tomography (CT) technology in the medical field. In the case of relative angular motion between the detection system and the target, modulated laser echo pulse signals can be accurately acquired from multiple angles. After being reconstructed and processed by a dedicated algorithm, target projection imaging in the vertical direction of the laser can be realized. The imaging mechanism of LRT determines that, under the condition of sufficient laser echo signal-to-noise ratio, its imaging resolution is independent of the detection distance and system aperture, and is mainly related to the laser pulse width, detection circuit bandwidth, and acquisition system sampling rate. It has great potential in the detection and perception tasks of long-distance space targets.

[0003] The prerequisite for tomography is to obtain laser echo projections, and different laser detection systems can be combined with tomography. Existing laser reflection tomography mostly uses a linear detection system. In recent years, lidar has made great progress in incoherent laser detection represented by single photons. The performance of its detectors has been continuously improved, the imaging distance and resolution have been further increased, and the applications have been extended to fields such as safety detection, remote sensing, and autonomous driving. Compared with traditional detection systems, single-photon detection technology uses single-photon detectors and methods such as time-correlated single-photon counting to achieve detection of weaker signals with a longer integration time. It has higher detection sensitivity, stronger environmental adaptability, lower laser power requirements, and smaller system size. Replacing traditional linear laser detection means with single-photon detection technology enables the system to have the development potential to complete long-distance detection tasks under the requirements of miniaturization and low power consumption.

[0004] Laser imaging technologies mainly include laser scanning imaging technology, synthetic aperture lidar imaging technology, and reflection tomography lidar imaging technology. Laser scanning imaging has the advantages of high technology maturity and long operating range. However, the lateral resolution of this method is determined by the scanning step angle or the array pixel pitch. As the detection range increases, its imaging resolution will gradually decrease, and the single imaging time is long, and the data volume is large and cannot be processed in real time. Therefore, this method is not suitable for high-resolution imaging of space targets at long distances. Synthetic aperture lidar imaging has advantages such as high detection accuracy and strong anti-interference ability. However, there are still more new optical problems to be solved urgently in the time domain and space domain of this technology. There is still a large gap between the current SAL imaging level and the application at a distance of hundreds or even thousands of kilometers. Laser reflection tomography imaging is a new type of long-distance laser imaging method, different from traditional optical imaging methods and laser scanning imaging methods. Only a single detector is required to integrate the one-dimensional time flow signals related to the object depth at different angles of the target, and then the target contour image can be reconstructed. The advantages are the active imaging method, which is not affected by sunlight; at the same time, the spatial resolution of this method is independent of the operating range and only related to the pulse width, the bandwidth of the detector, and the noise, and does not depend on the receiving aperture. The direct detection method can be adopted, and the requirements for the laser, the detection system, and the working environment are relatively low, and the engineering implementation difficulty is low, and it can be expected to be realized on the existing basis. Compared with the traditional linear detection system, single-photon detection has the advantage of extremely high sensitivity and is the most potential way to achieve target detection at the kilometer level, meeting the requirements of its long distance and high resolution. However, conventional single-photon imaging technology has problems such as long imaging time and complex data processing, and it is difficult to meet the requirements for obtaining information of moving targets. If the single-photon detection technology is combined with laser reflection tomography imaging, the imaging range can be further improved, and the characteristics that the imaging resolution of RTL imaging is independent of the detection range and the system aperture and is mainly related to the laser pulse width, the detection circuit bandwidth, and the sampling rate of the acquisition system can be fully utilized under the condition that the echo signal-to-noise ratio is sufficient. Thus, laser detection imaging with centimeter-level resolution at hundreds and thousands of kilometers can be achieved.

[0005] The closest prior art is the application of the team of Xu Feihu from the University of Science and Technology of China: Single-Photon Reflection Tomography Imaging Method and Device (Xu Feihu, Ye Juntian, Li Zhengping, Pan Jianwei. Single-Photon Reflection Tomography Imaging Method and Device [P]. Chinese Patent: CN118884464A, 2024.11.01). This patent proposes a method for tomographic imaging using single-photon detection technology. The steps of this solution can be summarized into 5 steps (as Figure 1-2 shown):

[0006] 1. Transmit a Gaussian beam into free space to act on the target surface

[0007] 2. The single-photon detector collects the echo information

[0008] 3. Obtain a photon count - time histogram based on the photon echo information in step 2

[0009] 4. Obtain the time - domain waveform of the target object at this angle based on the photon count - time histogram obtained in step 3

[0010] 5. Perform tomographic reconstruction on the time - domain waveforms at different angles to obtain the three - dimensional surface contour of the object. The specific steps of step 5 are as follows:

[0011] 5.1 Perform Fourier transform on the photon count histograms measured at each angle to obtain frequency - domain vectors

[0012] 5.2 Multiply the frequency - domain vectors by a filtering function for filtering;

[0013] 5.3 Perform Fourier transform on the filtered frequency - domain vectors to obtain the filtered time - domain data

[0014] 5.4 Back - project each piece of time - domain data onto the object space voxels that contribute to this time - domain data; operation

[0015] 5.5 Fit the result after back - projection based on surface constraints to finally obtain the three - dimensional surface contour of the target object.

[0016] Although the existing technology can achieve laser reflection tomography imaging of a target using single - photon detection technology, this technology has the following technical defects:

[0017] (1) It does not consider single - photon detection and reflection tomography imaging of moving targets, only staying at single - photon tomography imaging of stationary targets. There are differences in single - photon data processing and reflection tomography data processing between moving target detection and stationary target detection.

[0018] (2) After obtaining the time - domain waveforms at different angles, this technical solution does not use data pre - processing algorithms such as registration and echo de - convolution. The registration algorithm aligns the multi - angle echo projection data with the target rotation center, which can effectively reduce the interference caused by random jitter between laser pulse emission and detector reception, and reduce image blurring. The echo de - convolution algorithm can effectively eliminate the convolution effect in the echo, reduce artifacts, and improve the imaging quality. These two methods can effectively improve the imaging quality of real laser reflection tomography.

[0019] (3) Laser reflection tomography technology is different in real - world applications and theoretical experimental scenarios. The projection angles obtained in theoretical experimental scenarios are often full - angle and the sampling intervals are dense. In actual application scenarios, problems of incomplete projection data processing are often encountered, including sparse projection angles and projection imaging problems under limited angles. The existing technology has insufficient tomographic reconstruction capabilities for limited - angle and angle - sparse scenarios. Summary of the Invention

[0020] In view of the deficiencies in the prior art, the present invention proposes a single-photon super-resolution imaging scheme (method and system) for moving targets.

[0021] In the first aspect of the present invention, a single-photon super-resolution imaging method for moving targets is proposed. The method uses an imaging system to implement the single-photon super-resolution imaging process of moving targets. The imaging system includes: a narrow-pulse picosecond laser, a beam spatial shaping and control module, a high-precision scanning and pointing module, a super-sensitive single-photon detection module, an echo photon signal registration and processing module, an echo photon signal waveform recovery module, and a moving target image reconstruction module. The method includes:

[0022] Step S1: The narrow-pulse picosecond laser emits laser light, which is output as detection laser light after preprocessing by the beam spatial shaping and control module; the photon waveform to be motion-restored is collected from the super-sensitive high-speed detection module.

[0023] Step S2: The target moves within the field of view. The lidar is always aligned with the target projection center through the high-precision scanning and pointing module, and step S1 is repeated to obtain the photon waveforms waiting for motion restoration of the target at different positions.

[0024] Step S3: Step S2 is repeated at a certain repetition frequency for the current motion route of the target to obtain the photon waveforms waiting for motion restoration of the target on the entire travel route.

[0025] Step S4: The echo photon signal waveform recovery module performs motion restoration on the photon waveforms waiting for motion restoration at all positions to obtain the corrected photon waveforms.

[0026] Step S5: The echo photon signal registration and processing module performs photon waveform registration on the photon waveforms corrected in step 4.

[0027] Among them, photon waveform registration means aligning the restored photon waveform data in the time dimension so that all echo data have a common time origin corresponding to the rotation center of the target, and the rotation centers of the echo data at different angles are aligned on the distance line determined by the connection line between the detection system and the target rotation center; and converting the position coordinates of the photon waveforms at different positions into the polar coordinate system, then the photon waveforms are used for imaging.

[0028] Step S6: The moving target image reconstruction module combines the sparse model and the TV minimization model in the manner of reconstructing the moving target image at a finite angle, and performs moving target image reconstruction on the ART-TV sparse reconstruction algorithm for the target contour image under finite angle sampling.

[0029] In the method, the moving target moves along a straight line with the shortest distances being {H1, H2, H3, ……, Hn}.

[0030] In the method, at the transmitting end, the beam spatial shaping and control module controls the shape of the laser beam and the excitation of the pulses, and the high-precision scanning and pointing module controls the output of the narrow-pulse picosecond laser to always point to the moving target, thereby completing the control of the detection laser beam.

[0031] In the method, at the receiving end, the ultra-sensitive single-photon detection module collects the target photon waveforms, and the photon waveforms are corrected and restored for motion in the echo photon signal waveform restoration module; according to the angle information provided by the high-precision scanning and pointing module, the photon waveforms are registered for angle in the echo photon signal registration and processing module, so that all echo data have a common time origin corresponding to the rotation center of the target, and the rotation centers of the echo data at different angles are aligned on the distance line determined by the line connecting the centers of the detection system and the target rotation center; the photon waveforms at different angles after registration and restoration are subjected to tomographic reconstruction in the moving target image reconstruction module.

[0032] In the method, the ART-TV sparse reconstruction algorithm in step S6 includes:

[0033] Step S6-1: Use the Kaczmarz relaxation method to perform ART iteration on the distance results obtained from the photon waveforms at different angles. The iterative process of the Kaczmarz relaxation method is as follows:

[0034]

[0035] Among them, is the j-th element of the reconstructed image connected end to end by rows at the (k + 1)-th iteration, ω i,j is the projection weight of the i-th ray on the n-th pixel of the image, P i is the projection value of the i-th ray, λ is the relaxation factor, and 0 < λ < 1;

[0036] Step S6-2: Perform TV minimization on the result obtained in step S6-1. The TV minimization is performed using the gradient descent method, and one gradient descent iteration is performed. The iteration method is as follows:

[0037]

[0038] Among them, is the reconstructed image at the (k + 1)-th iteration, TV is the total variation of the image, and β is the iteration factor;

[0039] Step S6-3: Let k = k + 1, and repeat steps S6-1 and S6-2 until the maximum number of iterations is satisfied.

[0040] In the second aspect of the present invention, a single-photon super-resolution imaging system for moving targets is proposed. The imaging system includes: a narrow-pulse picosecond laser, a beam spatial shaping and control module, a high-precision scanning and pointing module, a super-sensitive single-photon detection module, an echo photon signal registration and processing module, an echo photon signal waveform restoration module, and a moving target image reconstruction module. When the imaging system is in the working state, it performs:

[0041] Step S1: The narrow-pulse picosecond laser emits laser light, which is preprocessed by the beam spatial shaping and control module and then outputs the detection laser light. The photon waveform to be restored for movement is collected from the super-sensitive high-speed detection module.

[0042] Step S2: The target moves within the field of view. The lidar is always aligned with the target projection center through the high-precision scanning and pointing module, and step S1 is repeated to obtain the photon waveforms waiting for movement restoration at different positions of the target.

[0043] Step S3: For the current movement route of the target, step S2 is repeated at a certain repetition frequency to obtain the photon waveforms waiting for movement restoration on the entire travel route of the target.

[0044] Step S4: The echo photon signal waveform restoration module performs movement restoration on the photon waveforms waiting for movement restoration at all positions to obtain the corrected photon waveforms.

[0045] Step S5: The echo photon signal registration and processing module performs photon waveform registration on the photon waveforms corrected in step 4.

[0046] Among them, photon waveform registration means aligning the restored photon waveform data in the time dimension so that all echo data have a common time origin corresponding to the rotation center of the target, and the rotation centers of the echo data at different angles are aligned on the distance line determined by the connection line between the detection system and the target rotation center. And when the position coordinates of the photon waveforms at different positions are converted to the polar coordinate system, the photon waveforms are used for imaging.

[0047] Step S6: The moving target image reconstruction module combines the sparse model and the TV minimization model in the manner of reconstructing the moving target image at a finite angle, and performs moving target image reconstruction on the ART-TV sparse reconstruction algorithm for the target contour image under finite angle sampling.

[0048] Among them, the moving target moves along a straight line with the closest distances being {H1, H2, H3, ……, Hn}.

[0049] At the transmitting end, the beam spatial shaping and control module controls the shape of the laser and the excitation of the pulse, and the high-precision scanning and pointing module controls the output of the narrow-pulse picosecond laser to always point to the moving target, thereby completing the control of the detection laser.

[0050] At the receiving end, the ultrasensitive single-photon detection module collects the target photon waveforms, and the motion of the photon waveforms is corrected and restored in the echo photon signal waveform restoration module; the photon waveforms are angle-registered in the echo photon signal registration and processing module according to the angle information provided by the high-precision scanning and pointing module, so that all echo data have a common time origin corresponding to the rotation center of the target, and the rotation centers of the echo data at different angles are aligned on the distance line determined by the line connecting the detection system and the rotation center of the target; the photon waveforms at different angles after registration and restoration are tomographically reconstructed in the moving target image reconstruction module.

[0051] The ART-TV sparse reconstruction algorithm in step S6 includes:

[0052] Step S6-1: Use the Kaczmarz relaxation method to perform ART iteration on the distance results obtained from the photon waveforms at different angles. The iterative process of the Kaczmarz relaxation method is as follows:

[0053]

[0054] Among them, is the jth element of the reconstructed image connected end to end by rows at the (k + 1)th iteration, ω i,j is the projection weight of the nth pixel of the image by the ith ray, P i is the projection value of the ith ray, λ is the relaxation factor, and 0 < λ < 1;

[0055] Step S6-2: Perform TV minimization on the result obtained in step S6-1. The TV minimization is performed using the gradient descent method, and one gradient descent iteration is performed. The iteration method is as follows:

[0056]

[0057] Among them, is the reconstructed image at the (k + 1)th iteration, TV is the total variation of this image, and β is the iteration factor;

[0058] Step S6-3: Let k = k + 1, and repeat steps S6-1 and S6-2 until the maximum number of iterations is satisfied.

[0059] A third aspect of the present invention proposes an electronic device. The electronic device includes a memory and a processor. The memory stores a computer program. When the processor executes the computer program, a method for single-photon super-resolution imaging of a moving target according to the first aspect of the present disclosure is implemented.

[0060] A fourth aspect of the present invention provides a computer-readable storage medium. A computer program is stored on the computer-readable storage medium. When the computer program is executed by a processor, a method for single-photon super-resolution imaging of a moving target according to the first aspect of the present disclosure is implemented.

[0061] In summary, the present invention combines the single-photon detection system with reflection tomography lidar imaging, and uses the echo photon waveform recovery to replace the echo waveform data directly collected by the linear detection system. Based on the single-photon detection of stationary targets and the traditional laser reflection tomography technology, 1. Model the characteristics of the single-photon detection waveform of moving targets and design an algorithm for recovering the photon waveform of moving targets; 2. Conduct research on photon waveform registration and image reconstruction methods for moving targets under finite angles. Finally, single-photon super-resolution imaging of moving targets is achieved. Theoretically, the detection distance of laser reflection tomography can be increased by 2 to 3 orders of magnitude. By using the relative angular motion between the moving target and the platform, it has the advantages that the imaging time is only related to the relative angular motion time and the data processing is relatively simple. It can achieve accurate acquisition of the moving target information of single-photon super-resolution imaging of moving targets under the condition of incomplete projection. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0063] Figure 1 It is a flowchart of the prior art implementation.

[0064] Figure 2 It is a structural diagram of the prior art implementation.

[0065] Figure 3 It is an optical path diagram of the transceiver optical system according to an embodiment of the present invention.

[0066] Figure 4 It is a structural diagram of the imaging system according to an embodiment of the present invention.

[0067] Figure 5 It is a schematic diagram of the imaging process according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0068] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0069] Abbreviations and definitions of key terms (the following English abbreviation terms that appear hereinafter provide the corresponding English full names and Chinese translations, or detailed explanations of Chinese professional terms):

[0070] LRT: Laser Reflective Tomography, i.e., laser reflection tomography;

[0071] APD: Avalanche photodiode, i.e., avalanche photodiode;

[0072] CT: Computer Tomography, i.e., computerized tomography;

[0073] RTL: Reflective Tomography LiDAR, i.e., reflective tomography lidar.

[0074] The present invention proposes a single-photon super-resolution imaging method for moving targets. Conventional single-photon imaging technologies have problems such as long imaging time and complex data processing, making it difficult to meet the requirements for obtaining information on moving targets. Currently, the existing single-photon laser reflection tomography technology only stays at imaging stationary targets, and the imaging quality is not good, making it difficult to cope with the real laser tomography application scenarios with incomplete projections.

[0075] The present invention combines the single-photon detection system with reflective tomography lidar imaging, and uses the echo photon waveform recovery to replace the echo waveform data directly collected by the linear detection system. Based on the single-photon detection of stationary targets and the traditional laser reflection tomography technology, 1. Model the characteristics of the single-photon detection waveform of moving targets and design an algorithm for recovering the photon waveform of moving targets; 2. Conduct research on photon waveform registration and image reconstruction methods for moving targets under limited angles. Finally, realize the single-photon super-resolution imaging of moving targets. Theoretically, it can increase the detection distance of laser reflection tomography by 2 to 3 orders of magnitude, and utilize the relative angular motion between the moving target and the platform, with advantages such as the imaging time being only related to the relative angular motion time and relatively simple data processing, and can accurately obtain the information of moving targets for single-photon super-resolution imaging under the condition of incomplete projection.

[0076] Such as Figure 3-4As shown: The system consists of a narrow-pulse picosecond laser, a beam spatial shaping and control module, a high-precision scanning and pointing module, an echo photon signal registration and processing module, an echo photon signal waveform recovery module, and a moving target image reconstruction module. When the system operates, at the transmitting end, the beam spatial shaping and control module controls the shape of the laser and the excitation of the pulse, and the high-precision scanning and pointing module controls the output of the narrow-pulse picosecond laser to always point to the moving target, thus completing the control of the detection laser. At the receiving end, the ultra-sensitive single-photon detection module collects the target photon waveform, and the photon waveform is corrected and recovered for motion in the echo photon signal waveform recovery module. Immediately afterwards, the photon waveform will be angle-registered in the echo photon signal registration and processing module according to the angle information provided by the high-precision scanning and pointing module, so that all echo data have a common time origin corresponding to the rotation center of the target. In this way, the rotation centers of the echo data at different angles will be aligned on the distance line determined by the connection line between the detection system and the target rotation center. Finally, the registered and recovered photon waveforms at different angles will be tomographically reconstructed in the moving target image reconstruction module.

[0077] As Figure 5 shown, the closest distance between the moving target and the detection platform is H4, and the moving target moves along a straight line with the closest distances of H1, H2, H3, ……, Hn.

[0078] Step 1: The narrow-pulse picosecond laser emits laser light, and the photon waveform to be motion-recovered is collected from the ultra-sensitive high-speed detection module.

[0079] Step 2: The target moves within the field of view. Through the high-precision scanning and pointing system, the lidar is always aligned with the target projection center, and Step 1 is performed to obtain the photon waveforms to be motion-recovered at different positions of the target, such as H1, H2, H3, ……, Hn.

[0080] Step 3: For a certain motion route H1, H2, H3, ……, Hn of the target, Step 2 is performed at a certain repetition frequency, and finally the photon waveforms to be motion-recovered on the entire travel route of the target are obtained.

[0081] Step 4: Motion recovery is performed on the photon waveforms to be motion-recovered at all positions to obtain the corrected photon waveforms.

[0082] Step 5: Photon waveform registration is performed on the photon waveforms corrected in Step 4. Photon waveform registration means aligning the recovered photon waveform data in the time dimension so that all echo data have a common time origin corresponding to the rotation center of the target. In this way, the rotation centers of the echo data at different angles will be aligned on the distance line determined by the connection line between the detection system and the target rotation center. And the position coordinates of the photon waveforms at different positions are converted to the polar coordinate system, and at this time the photon waveforms can be used for RTL imaging.

[0083] Step 6: Based on the registration in Step 5, using the method of reconstructing the moving target image at a finite angle, combine the sparse model and the TV minimization model, that is, the ART-TV sparse reconstruction algorithm for the target contour image under finite angle sampling.

[0084] The ART-TV sparse reconstruction algorithm in Step 6 can be split into the following steps:

[0085] Step 6.1: Use the Kaczmarz relaxation method to perform ART iteration on the distance results obtained from the photon waveforms at different angles. The iterative process of the Kaczmarz relaxation method is as follows:

[0086]

[0087] where refers to the j-th element obtained by connecting the first and last elements of the reconstructed image row by row during the (k + 1)-th iteration, ω i,j is the projection weight of the i-th ray on the n-th pixel of the image, which is calculated in advance according to the detection angle corresponding to the photon waveform, P i is the projection value of the i-th ray, and λ is the relaxation factor (0 < λ < 1).

[0088] Step 6.2: Perform TV minimization on the result obtained in Step 6.1. The TV minimization is processed using the gradient descent method, and one gradient descent iteration is performed. The iterative method is as follows:

[0089]

[0090] where is the reconstructed image at the (k + 1)-th iteration, TV is the total variation of the image, and β is the iteration factor.

[0091] Step 6.3: Let k = k + 1 and repeat Steps 1 and 2 until the maximum number of iterations is satisfied.

[0092] Compared with the prior art, the advantages and positive effects of the present invention are as follows:

[0093] The current single-photon laser reflection tomography technology only stays at imaging static targets, and the imaging quality is not good, making it difficult to cope with the real laser tomography application scenarios of incomplete projections. The present invention combines the single-photon detection system with reflection tomography lidar imaging, and uses the echo photon waveform recovery to replace the echo waveform data directly collected by the linear detection system. Based on the single-photon detection of static targets and the traditional laser reflection tomography technology, the characteristics of the single-photon detection waveform of moving targets are modeled, and research is carried out on photon waveform registration and the method of reconstructing the images of moving targets under limited angles. Theoretically, it can increase the detection range of the traditional laser reflection tomography imaging by 2 to 3 orders of magnitude, and utilize the relative angular motion between the moving target and the platform, with advantages such as the imaging time being only related to the relative angular motion time and relatively simple data processing, and can achieve accurate acquisition of information on single-photon super-resolution imaging of moving targets in incomplete projection scenarios, being closer to the actual application scenarios of single-photon laser reflection tomography.

[0094] Please note that the technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification. The above embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it cannot be understood as a limitation to the scope of the invention patent. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of the present application, several deformations and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A single-photon super-resolution imaging method for moving targets, characterized in that: The method uses an imaging system to achieve the single-photon super-resolution imaging process of a moving target; the imaging system includes: a narrow-pulse picosecond laser, a beam spatial shaping and control module, a high-precision scanning and pointing module, a super-sensitive single-photon detection module, an echo photon signal registration and processing module, an echo photon signal waveform restoration module, and a moving target image reconstruction module; the method includes: Step S1: The narrow-pulse picosecond laser emits laser light, which is output as detection laser light after preprocessing by the beam spatial shaping and control module; the photon waveforms to be motion-restored are collected from the super-sensitive high-speed detection module. Step S2: The target moves within the field of view. The lidar is always aligned with the target projection center through the high-precision scanning and pointing module, and Step S1 is repeated to obtain the photon waveforms of the target waiting for motion restoration at different positions. Step S3: Step S2 is repeated at a certain repetition frequency for the current motion route of the target to obtain the photon waveforms to be motion-restored of the target on the entire travel route. Step S4: The echo photon signal waveform restoration module performs motion restoration on the photon waveforms to be motion-restored at all positions to obtain the corrected photon waveforms. Step S5: The echo photon signal registration and processing module performs photon waveform registration on the photon waveforms corrected in Step 4. Among them, photon waveform registration means aligning the restored photon waveform data in the time dimension so that all echo data have a common time origin corresponding to the rotation center of the target, and the rotation centers of the echo data at different angles are aligned on the distance line determined by the line connecting the detection system and the rotation center of the target; and when the position coordinates of the photon waveforms at different positions are converted to the polar coordinate system, the photon waveforms are used for imaging. Step S6: The moving target image reconstruction module combines the sparse model and the TV minimization model in the manner of reconstructing the moving target image at a finite angle, and performs moving target image reconstruction on the ART-TV sparse reconstruction algorithm for the target contour image under finite angle sampling.

2. The single-photon super-resolution imaging method for moving targets according to claim 1, wherein In the method, the moving target moves along a straight line with the closest distances being {H1, H2, H3, ……, Hn}.

3. The single-photon super-resolution imaging method for moving targets according to claim 2, wherein, In the method, at the transmitting end, the beam spatial shaping and control module controls the shape of the laser and the excitation of the pulse, and the high-precision scanning and pointing module controls the output of the narrow-pulse picosecond laser to always point to the moving target, thereby completing the control of the detection laser.

4. A method for single-photon super-resolution imaging of moving targets according to claim 3, characterized in that In the method, at the receiving end, the super-sensitive single-photon detection module collects the target photon waveforms, and the photon waveforms are corrected and restored for motion in the echo photon signal waveform restoration module; the photon waveforms are angle-registered in the echo photon signal registration and processing module according to the angle information provided by the high-precision scanning and pointing module, so that all echo data have a common time origin corresponding to the rotation center of the target, and the rotation centers of the echo data at different angles are aligned on the distance line determined by the line connecting the detection system and the rotation center of the target; the photon waveforms at different angles after registration and restoration are tomographically reconstructed in the moving target image reconstruction module.

5. The single-photon super-resolution imaging method for moving targets according to claim 4, wherein, In the method, the ART-TV sparse reconstruction algorithm in Step S6 includes: Step S6-1: Use the Kaczmarz relaxation method to perform ART iteration on the distance results obtained from photon waveforms at different angles. The iteration process of the Kaczmarz relaxation method is as follows: Among them, is the j-th element connected end to end by rows of the reconstructed image at the (k + 1)-th iteration, ω i,j is the projection weight of the i-th ray on the n-th pixel of the image, P i is the projection value of the i-th ray, λ is the relaxation factor, 0 < λ < 1; Step S6-2: Perform TV minimization on the results obtained in Step S6-1. The TV minimization is carried out using the gradient descent method, and one gradient descent iteration is performed. The iteration method is as follows: Among them, is the reconstructed image of the (k + 1)-th iteration, TV is the total variation of this image, and β is the iteration factor; Step S6-3: Let k = k + 1, and repeat Step S6-1 and Step S6-2 until the maximum number of iterations is satisfied.

6. A single-photon super-resolution imaging system for moving targets, characterized in that, The imaging system includes: a narrow-pulse picosecond laser, a beam spatial shaping and control module, a high-precision scanning and pointing module, a super-sensitive single-photon detection module, an echo photon signal registration and processing module, an echo photon signal waveform restoration module, and a moving target image reconstruction module. When the imaging system is in the working state, it performs the following: Step S1: The narrow-pulse picosecond laser emits laser light, which is output as detection laser light after preprocessing by the beam spatial shaping and control module; collect the photon waveforms to be motion-restored from the super-sensitive high-speed detection module. Step S2: The target moves within the field of view. The lidar is always aligned with the target projection center through the high-precision scanning and pointing module, and Step S1 is repeated to obtain the photon waveforms to be motion-restored at different positions of the target. Step S3: Repeat Step S2 at a certain repetition frequency for the current movement route of the target to obtain the photon waveforms to be motion-restored along the entire travel route of the target. Step S4: The echo photon signal waveform restoration module performs motion restoration on the photon waveforms to be motion-restored at all positions to obtain the corrected photon waveforms. Step S5: The echo photon signal registration and processing module performs photon waveform registration on the photon waveforms corrected in Step 4. Among them, photon waveform registration means aligning the restored photon waveform data in the time dimension so that all echo data have a common time origin corresponding to the rotation center of the target, and the rotation centers of the echo data at different angles are aligned on the distance line determined by the line connecting the detection system and the target rotation center; and converting the position coordinates of the photon waveforms at different positions into the polar coordinate system, then the photon waveforms are used for imaging. Step S6: The moving target image reconstruction module combines the sparse model and the TV minimization model in the manner of reconstructing the moving target image at a finite angle, and performs moving target image reconstruction on the ART-TV sparse reconstruction algorithm for the target contour image under finite angle sampling.

7. The single-photon super-resolution imaging system for moving targets according to claim 6, wherein, The moving target moves along a straight line with the closest distances being {H1, H2, H3, ……, Hn}.

8. A single-photon super-resolution imaging system for moving targets according to claim 7, characterized in that, At the transmitting end, the beam spatial shaping and control module controls the shape of the laser and the excitation of the pulse, and the high-precision scanning and pointing module controls the output of the narrow-pulse picosecond laser to always point to the moving target, thereby completing the control of the detection laser.

9. The single-photon super-resolution imaging system for moving targets according to claim 8, characterized in that, At the receiving end, the ultra-sensitive single-photon detection module collects the target photon waveform, and the photon waveform is corrected and restored for motion in the echo photon signal waveform restoration module; the photon waveform is angle-registered in the echo photon signal registration and processing module according to the angle information provided by the high-precision scanning and pointing module, so that all echo data have a common time origin corresponding to the rotation center of the target, and the rotation centers of the echo data at different angles are aligned on the distance line determined by the connection line between the detection system and the target rotation center; the photon waveforms at different angles after registration and restoration are tomographically reconstructed in the moving target image reconstruction module.

10. The single-photon super-resolution imaging system for moving targets according to claim 9, characterized in that, The ART-TV sparse reconstruction algorithm in step S6 includes: Step S6-1: Use the Kaczmarz relaxation method to perform ART iteration on the distance results obtained from the photon waveforms at different angles. The iterative process of the Kaczmarz relaxation method is as follows: Among them, is the j-th element of the reconstructed image connected end to end by rows at the (k + 1)-th iteration, ω i,j is the projection weight of the i-th ray on the n-th pixel of the image, P i is the projection value of the i-th ray, λ is the relaxation factor, 0 < λ < 1; Step S6-2: Perform TV minimization on the result obtained in step S6-1. The TV minimization is performed using the gradient descent method, and one gradient descent iteration is carried out. The iteration method is as follows: Among them, is the reconstructed image at the (k + 1)-th iteration, TV is the total variation of this image, and β is the iteration factor; Step S6-3: Let k = k + 1, and repeat steps S6-1 and S6-2 until the maximum number of iterations is satisfied.

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