39results about How to "Achieve precise focus" patented technology

The invention discloses an imaging method for a bistatic forward-looking synthetic aperture radar (SAR). Aiming at the defect existing when the existing method is used for the imaging process of the bistatic forward-looking synthetic aperture radar, the imaging method adopts a bistatic forward-looking SAR point target response two-dimensional frequency spectrum based on the least square polynomial fitting; the frequency spectrum is the least square approximation of the two-dimensional frequency spectrum with the accurate theory. According to the characteristics of bistatic forward-looking invariant SAR direction, variant range and nonlinear and variant Doppler centroid range of range cell migration in an RD (radar domain) domain, bistatic forward-looking SAR range migration correction, secondary-range compression and high-order phase compensation are realized by the frequency spectrum so as to accurately focus the bistatic forward-looking SAR. Compared with the traditional SAR imaging method and the bistatic forward-looking SAR imaging method, the method disclosed by the invention has higher imaging precision.

The invention discloses a method for imaging a stationary transmitter bistatic foresight synthetic aperture radar (ST-BFSAR). The method comprises the following specific steps: after obtaining a target echo, rectifying a two-dimensional space variant of a distance migration of the ST-BFSAR by using first-order Keystone transform, wherein an object which has a same bistatic distance sum at a slow time zero moment is moved to a same distance gate during the operation; and after the distance migration rectification is accomplished, balancing the Doppler chirp scaling of an object in the same distance gate by using a non-linear chirp scaling variant object so as to eliminate the space variant of the Doppler chirp scaling along a directional bit and accomplishing the directional bit compression, so that the precise focusing of the ST-BFSAR is realized, and the problem that the two-dimensional space variant during the data treatment of the ST-BFSAR cannot be solved by using a traditional SAR (Synthetic Aperture Radar) imaging method and an existing bistatic foresight SAR imaging method is solved.

The invention discloses an imaging processing method for a coprime sampling satellite borne SAR, which belongs to the field of signal processing. The imaging processing method comprises the followingsteps: after obtaining imaging parameters, echo data and a coprime sampling matrix, firstly carrying out the range-wise pulse compression on a coprime sampling SAR echo signal, then starting from a first range gate, calculating the number of range gates spanned by the range gate echo signal according to Doppler parameters of each range gate, constructing a corresponding sparse dictionary, and intercepting a two-dimensional observation signal on the basis of the range gate echo signal, and finally reconstructing the two-dimensional observation signal by using an improved sparse reconstruction algorithm adaptive to the sparsity of the two-dimensional observation signal, thereby obtaining backscatter information of a scene target. By adopting the imaging processing method for the coprime sampling satellite borne SAR, the influence of the change of the imaging parameters along with the range door for the sparsity reconstruction can be compensated, the full-scene accurate focusing can be realized, the imaging processing under a coprime sampling working mode can be realized, the imaging accuracy is high, and the practicability is high.

The invention discloses a high squint synthetic aperture radar imaging processing method, which comprises the steps of S1, calculating high squint synthetic aperture radar echo signals; S2, carrying out range fast Fourier transformation (FFT) and spatial-variant range walk correction on the echo signals, and removing range spatial-variant range walk; S3, carrying out range pulse compression and high-order range migration correction on the echo signals, and removing residual range migration; S4, carrying out azimuth spatial-variant property fitting of Doppler parameters on the echo signals; S5, balancing the Doppler centroid and the slope of frequency modulation of target points of the same range cell by adopting an extended azimuth nonlinear frequency modulation scaling algorithm; and S6, carrying out azimuth focusing so as to acquire an imaging result. The high squint synthetic aperture radar imaging processing method solves a range spatial-variant property and an azimuth spatial-variant property of the Doppler parameters, can realize precise focusing of monostatic SAR echo signals under a high-squint-angle condition, and can be widely applied to the fields of earth remote sensing, resource exploration, geological mapping, military reconnaissance and the like.

The invention discloses a dual-flight transfer variation bistatic forward-looking synthetic aperture radar imaging method. According to the problems of strong distance orientation coupling and two-dimensional spatial-variant properties in dual-flight transfer variation bistatic forward-looking synthetic aperture radar imaging, the method comprises the steps of firstly, adopting improved Keystone conversion to remove two-dimensional spatial-variant RCM and complete distance compression, then adopting an extended nonlinear CS algorithm to balance Doppler mass centers of target points of the same distance unit and the slope of frequency modulation, and finally obtaining an imaging result through orientation compression. According to the dual-flight transfer variation bistatic forward-looking synthetic aperture radar imaging method, the problem of two-dimensional spatial-variant under the transfer variation bistatic forward-looking mode is effectively solved, and therefore accurate focusing of a variation bistatic forward-looking synthetic aperture radar is achieved; the dual-flight transfer variation bistatic forward-looking synthetic aperture radar imaging method better solves the problems of spatial-variant range migration and Doppler parameters, and can be used for dual-flight transfer variation bistatic forward-looking synthetic aperture radar imaging.

The present invention discloses a bistatic foresight SAR frequency domain imaging method based on frequency spectrum optimization modeling. The method comprises the following steps: S1, performing data preprocessing, and obtaining echo signals; S2, performing two-dimensional Fourier transform of the echo signals, establishing the point target response optimal two-dimensional frequency spectrum mode of the system, and solving the point target response two-dimensional frequency spectrum through adoption of a difference evolution optimization method; S3, performing rough matching focusing of the point target response accurate two-dimensional frequency spectrum; S4, performing distance frequency transformation of the two-dimensional frequency spectrum; and S5, performing two-dimensional inverse Fourier transform of the two-dimensional frequency spectrum after the distance frequency transformation, and obtaining final complex images. The problem is overcome that the current imaging algorithm cannot process the space variation of the bistatic foresight SAR distance to the nonlinearity, an accurate bistatic foresight SAR two-dimensional frequency spectrum is obtained through the difference evolution optimization method, and the echo signals are subjected to imaging process on the two-dimensional frequency domain according to the point target response accurate two-dimensional frequency spectrum to realize the accurate focusing of the bistatic foresight SAR original data.

The invention discloses a range migration imaging method of a shift invariant bi-static synthetic aperture radar (SAR). According to the method disclosed by the invention, the shortest slant range of the frequency spectrum phase along a receiving station is linearly expanded based on the two-dimensional frequency spectrum of the bi-static SAR of the generalized Loffeld transformation, a Stolt frequency transformation expression is derived, and the migration correction, the residual secondary range compression and the residual azimuth compression of a residual range unit are conducted through the transformation, so that the spatial linearization and the frequency linearization of the residual phase can be realized, and the shift invariant bi-static SAR can be accurately focused. Compared with the existing shift invariant bi-static SAR range migration algorithm, the method disclosed by the invention has the advantages of simple form, relatively high accuracy and relatively high operation efficiency.

The invention discloses bi-static synthetic aperture radar time-domain fast imaging method. The bi-static synthetic aperture radar time-domain fast imaging method comprises the specific steps of adopting low-order approximation of a green function in a back-projection integral function to finish subaperture full view imaging, performing aperture synthesis and view division through iteration, synthesizing subaperture images at an upper-layer stage into synthetic aperture images at each iteration stage, finally finishing full-aperture imaging and accordingly achieving bi-static SAR accurate focusing. The bi-static synthetic aperture radar time-domain fast imaging method is characterized in that a method for block iteration projection from a signal space to an image space is adopted to achieve time-domain imaging, the rough sub-picture focusing is finished by utilizing the low-order approximation characteristic of the green function, and the focusing accuracy is gradually improved through the iteration.

The invention relates to a ranging device, which comprises a body, a receiving lens, a first locking wheel, a second locking wheel, a movable plate and a receiving component, wherein the body is provided with a first end and a second end; the first end is opposite to the second end, and the second end is provided with at least one guide rod; the receiving lens is connected to the first end of the body; the first locking wheel and the second locking wheel are connected to the second end of the body in a rotary mode; the movable plate is sleeved on the guide rod of the second end of the body in a movable mode and is arranged between the first locking wheel and the second locking wheel; and the receiving component is connected to the movable plate and is used for receiving light beams received by the receiving lens. The movable plate moves through the rotation of the first locking wheel and the second locking wheel so as to drive the receiving component to move on an optical axis.

The invention discloses a multi-micro part coplane adjusting working platform and a corresponding method based on one-way microscopic vision. The platform comprises a motion platform A, a motion platform B, a microscopic vision system, a holder base, a pitching platform, a holder, micro parts and a computer. The method comprises the following steps that firstly, the microscopic vision system is adjusted to a maximum visual field, and the micro parts are adjusted into the visual field so as to form a clear image; then the image is processed to obtain the positions of the parts in the image, and the motion amount that the parts are moved to the holder in the center of the visual field is obtained through computation; finally, some micro part is moved to the center of the visual field, the vision system is adjusted to a minimum visual filed, the part is precisely focused, then the other parts are moved to the center of the visual filed in sequence, and all the parts form clear images in the vision system. The multi-micro part coplane adjusting working platform and the corresponding method based on one-way microscopic vision have the advantages that micron dimension coplane adjustment precision is realized, the method is simple and easy to carry out, and the execution efficiency is high.

The invention provides an azimuth wide-beam synthetic aperture radar imaging method and device, and a computer-readable storage medium, wherein the imaging method comprises the steps of: segmenting echo data in the azimuth direction, so that at least two data segments are obtained; according to each data segment, performing imaging by respectively adopting a time-domain backward projection algorithm, so that a first image corresponding to each data segment is obtained; determining strong scattering points in various first images, and determining to-be-compensated phases of data segments corresponding to the various first images; splicing the to-be-compensated phases of the various data segments, so that the full-aperture to-be-compensated phase is obtained; and, compensating the echo dataaccording to the full-aperture to-be-compensated phase, and performing imaging by adopting the time-domain backward projection algorithm according to the compensated echo data, so that a second imagecorresponding to the compensated echo data is obtained. By means of the azimuth wide-beam synthetic aperture radar imaging method and device in the invention, the low-frequency wide-beam synthetic aperture radar imaging quality is improved; and precise focusing is realized.

The invention discloses a laser differential correlation confocal Raman spectrum test method and device, and belongs to the technical field of micro-spectrum imaging. The differential confocal microscopic imaging system is constructed by using reflected light, so that high-precision tracking of a sample focus and high-spatial-resolution detection of geometric morphology are realized; raman scattering light is used for constructing a confocal Raman spectrum imaging system, two Raman spectrum signals at equivalent defocusing positions before and after a focus of a Raman collection lens are obtained by moving a Raman pinhole in the measurement process, and related product processing is performed on the two Raman signals to obtain related Raman spectrum information of a measured position; a confocal Raman system point spread functionis compressed to realize high spatial resolution Raman spectrum imaging; and the two points are combined to realize image-image-in-one imaging with high spatial resolution. The method and device have the advantages of real-time focus high-precision tracking, high spatial resolution, high signal-to-noise ratio and the like, and can be widely applied to the fields of biomedicine, physical chemistry, material science and the like.