236 results about "Self-focusing" patented technology

The invention discloses a space-variant self-focusing imaging method for a missile-borne synthetic aperture radar sea surface moving target. The method comprises the following steps: acquiring a radar fundamental frequency echo signal; performing range pulse pressure and range migration correction on the radar fundamental frequency echo signal to obtain a correction signal, and further obtaining a coarse focusing radar image; extracting a single defocusing target image in the coarse focusing radar image, and inverting the single defocusing target image to an echo data domain to obtain data of single target energy; performing correction to obtain data after correction of the residual range walk; selecting a part of distance units from the data after the residual range walk is corrected, performing Doppler frequency modulation rate estimation on the selected part of distance units by adopting fractional Fourier transform, fitting the estimated Doppler frequency modulation rate by adopting a space-variant phase error model, and constructing a space-variant phase error compensation function of the target; and compensating the data after the correction of the residual range walk, and imaging. According to the invention, the refocusing effect of the moving ship target can be improved.

The invention provides a self-focusing type wafer three-dimensional shape precision detection device and method. The self-focusing type wafer three-dimensional shape precision detection device comprises a super-radiation light-emitting diode, an optical fiber coupler, a microscopic reference arm provided with a reference arm microscope objective, a self-focal length wafer scanning platform of a microscopic scanning platform, a near-infrared reflection type spectrograph and an upper computer. During detection, near-infrared broadband light radiated by the diode is coupled into the optical fiber coupler and then is divided into detection light and reference light; moving the wafer to be detected to the focal point of the detection light; the detection light is focused on a to-be-detected wafer sample to form measurement light carrying sample surface information, then the measurement light is backscattered by the sample surface and interferes with the reference light at the optical fiber coupler, a formed interference light signal is captured by the near-infrared reflection type spectrometer and then is transmitted into the upper computer, the wafer sample is moved at the focus of the detection light, and the measurement light is transmitted to the lower computer. Performing X-axis and Y-axis scanning to obtain three-dimensional shape data of the wafer; according to the invention, the high-precision nondestructive detection of the three-dimensional shape of the chip can be realized under the condition that the chip sample is not damaged.

The invention discloses a light path system based on a gas-filled hollow-core optical fiber, and the system comprises a spectrum broadening device which comprises a first gas extraction chamber, a gas inlet chamber and a second gas extraction chamber, the first gas extraction chamber and the second gas extraction chamber are located at the two ends of the gas inlet chamber respectively, and the first gas extraction chamber and the gas inlet chamber are separated through a first sealing part; the second air exhaust chamber and the air inlet chamber are separated through a second sealing piece; the spectrum broadening device is internally provided with a hollow-core optical fiber and is provided with at least one through hole penetrating through the pipe wall of the hollow-core optical fiber, the two ends of the hollow-core optical fiber penetrate through the first sealing piece and the second sealing piece respectively so that the two ends of the hollow-core optical fiber can be communicated with the first air suction chamber and the second air suction chamber respectively, and the through hole is located in the air inlet chamber. The two ends of the hollow-core optical fiber are subjected to air exhaust, so that the ionization rate and the self-focusing effect generated when the laser is output after the spectrum of the inflated hollow-core optical fiber is broadened can be remarkably reduced, the requirement for improving the power input of the laser is met, and a light path system can bear higher laser monopulse energy compression.

An apparatus and method for radiation measurement are used to determine clearance of a rotating gas turbine component. The apparatus includes a probe body on a stationary component outward of the rotating component and a pair of sensor assemblies coupled to the probe body. Each sensor assembly includes a plurality of prisms coupled to the probe body Each prism of the plurality of prisms has a distinct angular orientation to direct radiation from the focusing lens to the rotating component surface off-axis with respect to an axis of the respective radiation source of the pair of radiation sources and with less directional variation than radiation from the respective radiation source.

The invention relates to the field of electromagnetic calculation, in particular to a petal-shaped Bessel light-based distance measurement method in hypersonic plasma turbulence, which comprises the following steps of: simulating plasma sheath turbulence by establishing a multi-layer random phase screen, calculating diffraction transmission of petal-shaped Bessel light after the petal-shaped Bessel light passes through the turbulence, and capturing intensity distribution of reflected light beams; the rotation angle is determined based on the correlation with the ideal intensity distribution, and high-precision distance measurement is realized by using the linear relation between the rotation angle and the propagation distance. The petal-shaped Bessel light is formed by superposing two Bessel mode light beams with different orbital angular momentum orders, has a spatial structure strongly related to the propagation distance, and can keep higher stability and anti-interference capability in a turbulent environment. By combining the self-focusing and approximately non-diffraction characteristics of the Bessel beam, the target detection and distance measurement precision in hypersonic plasma turbulence is remarkably improved, and reliable technical support is provided for communication and target detection of hypersonic aircrafts.

The invention discloses a path and focal nucleus variable high-intensity self-focusing ultrasonic transducer, and relates to the technical field of ultrasonic treatment, the path and focal nucleus variable high-intensity self-focusing ultrasonic transducer comprises an upper seat device and a sliding device, the upper seat device comprises multiple sets of focusing units, and the multiple sets of focusing units define a paraboloid structure along the same axis; the sliding device is arranged along the central axis of the paraboloid structure and can reciprocate along the central axis, when the sliding device moves into the paraboloid structure, the focusing unit slides outwards along the paraboloid to be unfolded, and when the sliding device moves away from the paraboloid structure, the focusing unit slides inwards along the paraboloid to be folded; according to the invention, by adjusting the unfolding or folding of the focusing unit, the dynamic adjustment of the size and shape of the focal nucleus is realized to adapt to tumors with different sizes and shapes, and the problems that the focal nucleus of the traditional ultrasonic transducer cannot be adjusted and the treatment adaptability is poor are solved.

A telescopic varifocal self-rotating OCT (optical coherence tomography) scanning probe belongs to the technical field of industrial surface imaging and comprises a casing large sleeve, a casing small sleeve, a probe and a miniature hollow motor. The shell large sleeve is an outermost layer straight sleeve, and the transparent short sleeve is adhered to the tail end of the shell large sleeve. The small sleeve is arranged in the large sleeve of the shell, the probe is arranged in the small sleeve, and the small sleeve is adhered to the motor sleeve; the probe comprises an optical fiber, a capillary glass tube, a self-focusing lens and a plano-convex lens which are sequentially arranged along the optical fiber in the direction from light incidence to a to-be-detected sample, and the probe part is bonded through optical cement. The tail end of the right side of the micro hollow motor is bonded with the reflecting prism, and the tail end of the left side of the micro hollow motor leads out a wire. According to the invention, the rotation of the hollow shaft of the micro hollow motor is controlled to drive the reflecting prism adhered to the tail end of the hollow shaft to rotate, so that the light path is changed, the drop point of the focused light beam is adjusted, the rapid circumferential scanning of various hole cavities is realized, and the imaging quality, the measurement capability and the measurement efficiency are improved.

The invention discloses an atmospheric transmission vortex light topological charge detection method based on light intensity distribution. The method comprises the following steps: firstly, generating a vortex light beam with a self-focusing characteristic, simulating an atmospheric turbulence environment by adopting a multi-phase screen method, calculating a transmission process of the light beam under an atmospheric turbulence condition by adopting a step-by-step Fourier method, and obtaining a light intensity distribution image at a focusing point; self-adaptive cutting and normalization preprocessing based on the mass center are carried out on the light intensity distribution image; and constructing a ResNet18 deep learning model containing eight residual blocks, and training by using the constructed data set to realize automatic identification of the topological charge number.

The invention provides an SAR (Synthetic Aperture Radar) self-focusing method for multi-stage sub-aperture segmentation, and relates to the technical field of radar signal processing. The method comprises the following steps: preprocessing original SAR echo data to obtain a coarse focusing SAR image; secondly, for a coarse focusing SAR image, reducing the image resolution by dividing frequency domain sub-apertures, and reducing the sensitivity of the image to a motion error; then, a focusing algorithm based on a model or a phase gradient is adopted in each stage of sub-aperture, and the image quality of each stage of sub-aperture with a good focusing effect is obtained; and finally realizing global focusing of the SAR image through step-by-step sub-aperture focusing. Compared with direct division of a plurality of sub-apertures, the method greatly improves the focusing effect of the SAR image while improving the efficiency, and is effectively verified in simulation, actual airborne flight and satellite-borne data.

The invention belongs to the technical field of laser vibration measurement, and provides a self-focusing laser Doppler vibration measurement method and system capable of resisting self-vibration of an optical fiber, and the method comprises the steps: adding a compensation light path which is used for sensing and generating reference light which is equal to an interference signal in amplitude and is opposite to the interference signal in real time in a Doppler vibration measurement light path, and taking the minimum mean square error as a self-adaptive matching criterion; interference phases obtained by synchronous demodulation of the compensation light path and the main light path are subjected to adaptive matching and cancellation in amplitude and phase dimensions, residual errors of vibration of the vibration measurement system and other environmental interferences are suppressed below noise of the vibration measurement system, and the purpose of balancing and weakening optical fiber vibration interferences in an instrument is achieved. The influence of the vibration factor of the instrument is reduced, and the interference influence is accurately eliminated through amplitude and phase matching by a demodulation algorithm corresponding to a compensation light path; meanwhile, by dynamically observing and updating the return light intensity threshold, low-frequency disturbance is resisted, and accurate automatic focusing is achieved.

The invention discloses a method for generating a multi-focus circular beam based on an all-dielectric metasurface, and the method specifically comprises the following steps: 1, constructing the all-dielectric metasurface which is composed of a plurality of arranged super atoms; the super atom comprises a square SiO2 substrate, and a rectangular Si nanorod is arranged on the SiO2 substrate; and 2, irradiating the all-dielectric metasurface by using left-hand circularly polarized light as incident light, and modulating the incident light by using a geometric phase and a propagation phase, so that emergent light of the all-dielectric metasurface forms a right-hand circularly polarized multi-focus circular light beam. According to the invention, the circularly symmetrical light beams with a plurality of self-focusing focuses can be efficiently and flexibly generated, and the number and the focal depth of the focuses can be adjusted as required.

The invention belongs to the technical field of radar signal processing, discloses a plasma sheath multi-order dispersion effect error compensation method, system, equipment, medium and program product based on two-step self-focusing processing, and aims to solve the problem of plasma sheath multi-order dispersion effect error influence of radar in the hypersonic flight vehicle imaging detection process. Obtaining a strong scattering point target in the image through strong point target search, and constructing a dispersion effect error compensation image matrix; based on a maximum contrast self-focusing processing principle and an image focusing theory, iteratively processing and compensating second-order and third-order phase errors of a dispersion effect; outputting an image after the multi-order dispersion effect error compensation, and realizing the accurate compensation of the multi-order dispersion effect error of the target wrapped by the plasma sheath; systems, devices, media for implementing the method, program products including computer programs implementing the method; the method has the characteristics of high dispersion effect error compensation precision, high compensation efficiency, strong adaptability and simple compensation processing steps.

The invention belongs to the technical field of optical measurement, and discloses an implementation device and method of a single-photon spectrograph, and the device comprises a spectral wavelength scanning module which is used for collecting a wide-spectrum optical signal, carrying out the wave division processing, and calculating the photon counting change rate between adjacent wavelengths; wavelength stepping is dynamically adjusted according to the photon counting change rate, self-adaptive scanning of spectrum change is achieved, and a single-spectrum optical signal is output; the self-focusing detection module is used for converting the single-spectrum optical signal into a photon event through a preset array channel; in a preset time window, calculating the variance and the Shannon entropy of each photon event, and constructing a local uncertainty index; performing spectral domain self-focusing and resampling according to the local uncertainty index to obtain photon counting data; high-precision, high-stability and high-efficiency spectrum light signal detection and visual analysis are realized.

The invention discloses an SAR image self-focusing distortion correction method and device, and belongs to the technical field of synthetic aperture radars. The method comprises the following steps: carrying out distance blocking and orientation sub-aperture division on a defocused SAR image, selecting a sample, and carrying out orientation decompression to a phase historical domain; performing azimuth dechirp processing on the sub-aperture data in each distance sub-block, and estimating a phase error through a standard PGA algorithm; after splicing sub-aperture phase errors and removing an overall linear phase, performing phase compensation and azimuth compression to obtain a focused image; and for azimuth distortion caused by residual linear phase of the compensated image, extracting a phase error linear term coefficient through a sliding window, deducing an azimuth shift distance in combination with Fourier transform time shift characteristics, and finally performing shift correction by adopting sinc interpolation. According to the method, the image focusing quality is improved, and meanwhile, the ground feature continuity and the image resolution are kept.

This invention discloses a phase compensation method for ship targets using ISAR based on block phase gradient autofocus. The steps include: pulse compression; range cell migration correction; range-oriented block segmentation; block phase compensation; calculation of the offset between adjacent image blocks; and image block alignment and stitching. This invention performs range-oriented block segmentation of the target echo, overcoming the shortcomings of existing technologies that ignore the spatial variation of rotational phase error, leading to defocusing in ship imaging, thus improving the accuracy of phase compensation and achieving good image focusing effect. Because this invention uses a phase gradient autofocus algorithm to compensate for the phase error within each block, and then uses a cross-correlation method to align and stitch the images of each block region, it overcomes the shortcomings of parameter estimation methods, such as complexity, time consumption, and poor real-time performance, and has the advantages of simple implementation, high efficiency, and strong real-time performance.

The invention discloses a block self-focusing ISAR (inverse synthetic aperture radar) imaging method and system based on an FPGA (field programmable gate array), and the method comprises the steps: obtaining ISAR echo data, and sequentially carrying out the preprocessing and global self-focusing processing, thereby obtaining a global self-focusing correction matrix; dividing the global self-focusing correction matrix into a plurality of sub-matrix blocks in a sliding window partitioning manner; performing minimum entropy self-focusing processing on each sub-matrix block to generate an optimized sub-matrix block; performing fast Fourier transform on the optimized sub-matrix blocks in the azimuth direction to generate two-dimensional image data; determining an offset according to an overlapping region of the adjacent sub-matrix blocks, performing cyclic shift processing on the two-dimensional image data corresponding to the current optimized sub-matrix block in the azimuth direction based on the offset, and aligning the two-dimensional image data corresponding to the previous adjacent optimized sub-matrix block; and outputting the aligned corrected two-dimensional image data as an ISAR imaging result. According to the invention, the azimuth focusing performance is improved, and the overall imaging quality is obviously improved.

The invention relates to the technical field of ultrafast laser, in particular to an ultraviolet laser damage inhibition method and device for a fused quartz optical element, and the method comprises the steps: obtaining oxy-18 modified DKDP crystals with oxy-18 isotope abundance higher than natural abundance; preparing the oxy-18 modified DKDP crystal into a wave plate matched with a preset ultraviolet laser wavelength; in an ultraviolet laser light path of a laser inertial confinement fusion device, a wave plate is arranged between a linear polarization state output end of ultraviolet laser and a fused quartz optical element; and enabling ultraviolet laser to sequentially pass through the linear polarization state output end and the wave plate to form circularly polarized light, and irradiating the circularly polarized light to the fused quartz optical element. The invention aims to realize the small-scale self-focusing effect of actively inhibiting fused quartz and solve the technical problem that a traditional material cannot be used as a large-aperture wave plate due to over-high transverse stimulated Raman scattering.

The invention discloses an SAR (Synthetic Aperture Radar) image self-focusing method and system based on error coefficient optimization. The method comprises the following steps: training a feature extraction module by using a defocused SAR image sample to establish a mapping relation between a defocused SAR image and a polynomial error coefficient; for a to-be-processed defocused SAR image # imgabs0 #, the defocused SAR image # imgabs1 # passes through a trained feature extraction module to obtain a polynomial error coefficient, the polynomial of a phase error vector is converted into an error matrix # imgabs2 #, the defocused SAR image # imgabs3 # is subjected to azimuth fast Fourier transform # imgabs4 # and then multiplied by the error matrix # imgabs5 #, and the defocused SAR image # imgabs3 # is obtained. And performing inverse fast Fourier transform # imgabs6 # on a result obtained by multiplication in the azimuth direction to obtain a focused SAR image # imgabs7 #. The SAR self-focusing method is small in manual intervention, high in calculation efficiency and better in interpretability, and the quality and effect of SAR image self-focusing are improved.

The present invention relates to the technical field of three-phase flow detection, and provides a fluorescent fiber optic probe device for three-phase flow detection, comprising: a packaging shell; a sapphire probe disposed within the packaging shell; a connected small-diameter self-focusing lens and a large-diameter self-focusing lens located above the sapphire probe; an integrated fiber bundle structure divided into a transmitting fiber and a receiving fiber within a main cavity; a laser transmitting module connected to the transmitting fiber; a collimating lens located above the receiving fiber; a trapezoidal waveguide structure located above the collimating lens; a first optical focusing assembly and a second optical focusing assembly disposed side by side above the trapezoidal waveguide structure, with a reflective volume holographic grating disposed below the first optical focusing assembly; a first photoelectric conversion module and a second photoelectric conversion module; and a main control module. The device of the present invention can effectively avoid optical power attenuation caused by optical fiber splitting and filters, thereby ensuring optical signal transmission efficiency and detection accuracy.

The invention discloses a handheld high-resolution millimeter-wave synthetic aperture radar imaging method. The method comprises the following steps: mixing signals acquired by a handheld high-resolution millimeter-wave radar to obtain intermediate-frequency signals; performing fast Fourier transform processing and residual video phase removal on the intermediate frequency signal; calculating the frequency response corresponding to the distance between the phase center of the radar antenna and the pixel point through linear interpolation; obtaining a preliminary result according to backward projection imaging; calculating position error estimation according to a minimum entropy self-focusing algorithm; and track correction is carried out according to the position error estimation, and then backward projection imaging is carried out again. The minimum entropy self-focusing backward projection algorithm provided by the invention takes image entropy minimization as an optimization target, compensates the position error of the phase center of the radar antenna through a coordinate descent method, does not need to depend on an external sensor, and effectively improves the imaging definition, thereby achieving compact and efficient imaging. The invention discloses a light and independent handheld high-resolution millimeter wave synthetic aperture radar system.

The invention provides a circumferential synthetic aperture sonar imaging motion compensation method based on a corner reflector, and the method comprises the steps: S1, carrying out the projection imaging of echo data after matched filtering, and determining the height of the corner reflector through an image variance; s2, according to the height of the corner reflector, the focusing position of the corner reflector is determined through the preliminary imaging result; s3, the distance between the corner reflector and the sonar is calculated according to the echo data when echoes are received each time; and S4, correcting the position of the sonar according to the focusing position of the corner reflector determined in the step S2 and the distance determined in the step S3, and performing projection imaging according to a new sonar position and echo data. According to the method, the corner reflector is used as an imaging reference target, the image quality of circumferential synthetic aperture imaging is improved, and the method is of great significance in reducing the calculation time of a self-focusing algorithm, improving the target imaging quality and the like.

The application discloses a method for generating an ultralong focal depth array beam, and belongs to the technical field of grating manufacturing. The method comprises the following steps: constructing a Bessel beam excitation phase and a circular Airy beam excitation phase, constructing a composite phase distribution according to the array Bessel beam excitation phase and the array circular Airy beam excitation phase, and encoding the composite phase distribution to a metasurface; irradiating the metasurface with a linear polarization state plane wave, so that a left-handed circular polarization component excites an array Bessel beam, and a right-handed circular polarization component excites an array circular Airy beam; the array circular Airy beam is converted into a Bessel propagation mode after self-focusing, is spliced with the array Bessel beam in an axial direction to form a continuous light field distribution, and an ultralong focal depth array beam is obtained. The method can be applied to the fields of parallel laser processing, three-dimensional microscopic imaging and microparticle manipulation, and can extend the focal depth of the array Bessel beam while keeping the transverse resolution close to the diffraction limit.

The present invention discloses a self-focusing method and device based on an affine coordinate system BP for a high squint SAR, the method comprising: performing range pulse pressure and coarse compensation on the received original echo signal to obtain a coarse compensation signal; establishing an affine coordinate system PX with the beam center P as the origin in the imaging scene based on the coarse compensation signal; ac Y ac Z ac , and in this coordinate system X ac Y ac The imaging scene grid is established within a plane; the imaging scene grid is divided into multiple subgrids, and rapid BP imaging and spectrum tilt correction processing are performed on the coarse compensation signal on a subgrid-by-subgrid basis to obtain multiple coarsely focused subimages; a phase error structure of different coarsely focused subimages is constructed to achieve estimation and inversion of the two-dimensional phase error; the two-dimensional phase errors corresponding to the different coarsely focused subimages are compensated into their respective coarsely focused subimages to obtain multiple finely focused subimages; and the multiple finely focused subimages are spliced ​​to obtain a final finely focused image. This invention can improve SAR imaging quality in high squint modes.

The invention discloses a remote high-depth-of-field LIBS self-focusing detection device for a lunar soil environment, and the device comprises a variable-curvature primary mirror which is provided with a central light through hole, and one side of the variable-curvature primary mirror is sequentially provided with a beam expanding assembly, a low-pass dichroscope, a focusing system, and a spectrometer; the multi-secondary-mirror zooming structure is arranged on the other side of the curvature-variable primary mirror; wherein the low-pass dichroscope corresponds to the transmitting end of the pulse laser; the variable-curvature primary mirror comprises a plurality of reflectors which are sequentially stacked from left to right, wherein the curvatures of the reflectors are sequentially increased. The multi-mirror zoom structure comprises a guide rail capable of rotating and axially moving; and the plurality of secondary mirrors with different curvature radiuses are sequentially arranged on the guide rail through the electronic clutch, and the secondary mirrors can diverge and reflect the light beams. According to the invention, the super-large depth of field with the axial depth of 1.5 cm is constructed by using the variable-curvature primary mirror, and the large-range coverage of the full life cycle area of the expanded plasma is realized.

The invention relates to a method for generating self-focusing by a Lorentz non-uniform correlation partially coherent pulse light source, which comprises the following steps of: firstly, by constructing a pulse light source with a Lorentz non-uniform time correlation structure, defining a time domain mutual coherence function of the pulse light source so as to represent pulse coherence characteristics; the mutual coherence function is based on the generalized Huygens-Fresnel principle, a mutual coherence function expression of the LNUC partially coherent pulse light source at the transmission distance z is deduced, and the coherence degree is in Lorentz distribution and has the non-uniform correlation characteristic. An average intensity expression is further obtained according to a mutual dry function expression, intensity distribution has a self-focusing phenomenon in evolution, and the characteristic has potential application value in the fields of pulse beam shaping and micromachining.

The invention relates to a terahertz video SAR (Synthetic Aperture Radar) fine imaging method, device and equipment and a medium. The method comprises the following steps of: approximating a distance difference into a linear function related to the speed of a platform, correcting range walk through a keystone method, considering the influence of the vertical distance from scattering points of different distance units to an air route on imaging quality in secondary phase error compensation, constructing a corresponding secondary phase error function, and meanwhile, calculating the imaging quality under the minimum entropy criterion. According to the method, secondary phase errors in radar signals are accurately compensated, after phase gradient self-focusing, the image is still affected by speckles, at the moment, an anisotropic extended filtering method is adopted, the influence of the speckles is restrained, and a fine terahertz video SAR image can be obtained through the method.

The gallium nitride-based semiconductor blue laser chip comprises a substrate, a lower coating layer, a lower waveguide layer, an active layer, an upper waveguide layer and an upper coating layer which are sequentially arranged from bottom to top. The distribution characteristic of density in the lower waveguide layer of the gallium nitride-based semiconductor blue laser chip is specifically designed, so that the lower waveguide layer forms a lower waveguide layer for inhibiting optical catastrophe, the density distribution of the lower waveguide layer is regulated and controlled, thermal degradation and thermal mismatch of an active layer are inhibited, non-radiative recombination is reduced, the optical catastrophe is inhibited, and meanwhile, the optical catastrophe is inhibited. Longitudinal, transverse and lateral drift uniformity of carriers in an active area is improved, the heat conduction efficiency of a laser cavity is improved, heat accumulation in the laser is reduced, the coupling rate of pump light to an upper energy level of laser is improved, waste heat and laser gain saturation are inhibited, and the laser efficiency is improved. And the hole burning effect caused by self-focusing and beam distortion due to uneven thermal stress and increase of the refractive index is reduced, so that optical catastrophe is inhibited.

A dynamic 3D light scattering particle size distribution measurement device includes a polarization splitter for generating an s laser beam with perpendicular polarization and a p laser beam with parallel polarization that travels parallel to and spaced apart from the s laser beam. A lens is used to focus the s laser beam and the p laser beam onto a common focus area inside a sample holder holding a sample whose particle size is to be measured. An s light intensity detector measures a time-resolved s light intensity from s backscattered light from the focus area. An s-polarisation filter allows perpendicularly polarized light to pass, resulting in s measuring light, and includes a light detector for time-resolved intensity measurements of the s measuring light. A p light intensity detector measures a time-resolved p light intensity detects p backscattered light from the focus area, and includes a p polarization filter that allows parallel polarized light to pass. A light detector provides for time-resolved intensity measurement of the p measuring light, and an evaluation unit automatically calculates the particle size distribution from the time-resolved p light intensity and the time-resolved s light intensity.

The present invention relates to the field of electromagnetic calculations, and specifically relates to a method for ranging based on petal-shaped Bessel light in hypersonic plasma turbulence. This method simulates plasma sheath turbulence by establishing a multi-layer random phase screen, calculates the diffraction transmission of petal-shaped Bessel light through the turbulence, captures the intensity distribution of the reflected light beam, and determines the rotation angle based on its correlation with the ideal intensity distribution. The high-precision ranging is achieved by using the linear relationship between the rotation angle and the propagation distance. The petal-shaped Bessel light is formed by superimposing two Bessel mode beams with different orbital angular momentum orders, and has a spatial structure strongly correlated with the propagation distance, capable of maintaining high stability and anti-interference ability in a turbulent environment. By combining the self-focusing and approximately non-diffracting characteristics of the Bessel beam, the present invention significantly improves the target detection and ranging accuracy in hypersonic plasma turbulence, providing reliable technical support for the communication and target detection of hypersonic vehicles.

This application relates to the field of space imaging technology and provides a method for decoupling translational and rotational motion in space-based microwave imaging of space targets based on parameter estimation. The method first uses adjacent cross-correlation and self-focusing methods to perform preliminary compensation for the translational motion components of the microwave imaging echo data. Then, using the first-order translational motion parameters fitted by the former as initial values ​​and minimizing the image entropy of the echo data as the cost function, it combines Keystone transform to optimize and compensate for the translational linear phase components. Next, it uses Keystone transform to compensate for the spatially varied range cell migration caused by the rotational motion components. Finally, it performs a second compensation for the residual translational motion components, obtaining echo data after almost complete compensation of the translational and rotational MTRC. By performing spatially varied phase error compensation and azimuth compression on this data, the imaging result of the space target can be obtained. This method achieves a balance between the efficiency and accuracy of parameter estimation, effectively improving imaging quality.