197 results about "Synthetic aperture imaging" patented technology

The invention provides a long-lead source transient electromagnetic ground-air detecting method which comprises the following steps of: detecting a deep geologic target body by a working device adopting a long-lead source transient electromagnetic terra-air detecting method to obtain transient electromagnetic observing data; converting the transient electromagnetic observing data into transient electromagnetic virtual wave data and obtaining a transient electromagnetic synthetic aperture data volume by adopting a multipoint data synthesis method to finish data reserve for carrying out fine explanation on the deep geologic target body; and obtaining a transient electromagnetic synthetic aperture imaging profile by adopting a Kirchhoff offset imaging method and a speed modeling method and processing and explaining the transient electromagnetic synthetic aperture data volume to finish fine detection on the deep geologic target body and obtain the information of the deep geologic target body. The long-lead source transient electromagnetic ground-air detecting method can be used for carrying out accurate exploration on the deep geologic target body, thereby obtaining the accurate and detailed geologic information of the deep geologic target body so as to achieve the aim of searching various deep geologic target bodies.

A synthetic aperture three-dimensional fluid flow imaging apparatus is provided. The apparatus includes a plurality of cameras. At least two of the cameras are oriented to view a volume along mutually non-parallel directions. The cameras are connected to a programmable computer. The computer captures images from the cameras to generate three dimensional intensity fields. The computer can refocus the images on at least one refocus plane to generate reconstructed three dimensional intensity fields on a plane within the volume. Intensity field cross-correlation is performed on the reconstructed three dimensional intensity fields to extract velocity fields within the volume. The velocity fields represent velocities of objects or fluid phases within the volume. These velocity fields can be recorded for later use.

The invention relates to a sparse optical synthetic aperture imaging method based on a subaperture shutter modulation phase difference method, and can be used for detecting aberration of all subapertures of a sparse optical synthetic aperture imaging system, co-phase error of multiple apertures and imaging beam atmospheric turbulence distortion and restoring the high-resolution image of a target in real time. Switching module is performed on each or multiple subapertures of the sparse optical synthetic aperture imaging system in turn by utilizing an electronic shutter, and the corresponding images are recorded by utilizing an image sensor. A series of recorded sub-images are processed by using the phase difference algorithm based on subaperture shutter modulation so that the subaperture aberration, the co-phase error of multiple apertures and the imaging beam atmospheric turbulence distortion can be detected simultaneously, and the high-resolution image of the target can be reconstructed. The sub-images having phase difference are generated by adopting shutter spatial modulation, and aberration detection and image restoration are integrated so that the method has advantages of being high in aberration detection precision, compact in structure, low in cost and convenient to use.

The invention discloses a maneuvering object frequency modulation stepping retrosynthesis aperture imaging method, belonging to the radar signal processing and imaging technology field. The Maneuvering object frequency modulation stepping retrosynthesis aperture imaging method comprises steps of (1) obtaining a rough distance image after a radar echo is processed by de-slopping, (2) estimating a target movement parameter from a rough distance image signal FRAF transformation spectrogram, (3) utilizing parameter estimate values of various pulse trains to fit an accuracy value, (4) constructing a phase compensation function and compensating a rough distance image signal, (5) obtaining an object fine distance image in a slow time dimension FFT by the compensated rough distance image signal, (6) performing phase focusing on an object fine distance image signal, (7) performing turntable imaging to obtain an ISAR image. The maneuvering object frequency modulation stepping retrosynthesis aperture imaging method can stably estimate the target movement parameter under the low signal to noise ratio, can compensate the distance generated by the object motion and the doppler migration, realizes the accumulation of the phase and parameters, improves the imaging capability of the frequency modulation stepping radar on the maneuvering object under the low signal to noise ratio and has a popularization value.

The invention discloses a phase shift error correction device for a sparse optical synthetic aperture imaging system, which is composed of a sparse optical synthetic aperture telescope, an adaptive optical system, an error compensator, error compensation controller, a beam splitter, a beam switch, achromatic condition imaging elements, scientific cameras and an error calculation unit. The beam switch, the achromatic condition imaging element, the scientific camera and the error calculation unit form an error detection module; the error compensator and the error compensation controller form an error compensation module; and the other set of achromatic condition imaging element and the scientific camera form an imaging module. The error detection module is used for solving the phase shift error; and the error compensation module is used for compensating the phase shift error. Complete correction of the phase shift error in the system can be implemented by performing the detection process and the compensation process for different sub-aperture pairs. The device can effectively implement the function of detecting and compensating the phase shift error, and has improvement on aspects of accuracy, real-time property and the like in comparison with the detection technology of the current similar system.

The invention provides a one-dimensional mirror image synthetic aperture radiation imaging method. The method comprises the following steps of: constructing a linear equation set by utilizing the relation among relevant output, the cosine visibility and the scene brightness temperature distribution, solving the linear equation set to obtain a cosine visuality; and then reconstructing scene brightness temperature distribution through a mode of carrying out anti-cosine transformation or solving a generalized inverse matrix of an impulse response matrix. In the invention, the imaging performance of a traditional synthetic aperture imaging system with a large array element number is acquired by using a small array element number, thereby the complexity of the structure of the traditional synthetic aperture imaging system and the complexity of signal processing are effectively reduced.

The invention discloses a sparse optical synthetic aperture imaging device based on three apertures and a light beam combination correction method of the device. The device and the method can be used for remarkably improving the imaging resolving power of a target and effectively weakening the influence of transmission media such as atmosphere and optical systems. The device mainly comprises a telescope sub-array, an optical distance precision adjustment system, an oblique error correction unit, an imaging light sub-beam combination and imaging system and the like. After light waves reflected or scattered by the target are respectively acquired by the telescope sub-array, three imaging light waves share a phase by the aid of the optical distance precision adjustment system and the oblique error correction unit, and finally, high-resolution synthetic aperture imaging for the target is realized by the imaging light sub-beam combination and imaging system. The device has the advantages of simple and compact structure, small size, light weight, high environmental adaptability, capability of simultaneously ensuring optical distance precision adjustment range and adjustment accuracy and the like.

The invention relates to method for measuring synthetic aperture sonar movement error and underwater sound channel error. The invention employs an irradiation matrix which is arranged along platform trace and different phase center to irradiate plural orthogonal signal with same frequency at the same time.

The invention belongs to the technical field of synthetic aperture imaging and discloses a radar video imaging method based on no-interpolation fusion fast back-projection. First data is subjected tosubaperture division through an FFBP algorithm, and then each subaperture data forms a local rectangular coordinate aperture image with the center of the subaperture as the origin. The subaperture image only utilizes partial aperture data and thus is characterized by having a low azimuth resolution. Every two formed subaperture images are merged to obtain a new higher-resolution sub-image, and theprocess is performed in an iterative manner until a fully resolved polar coordinate image is obtained, and finally the polar coordinate image is interpolated to a rectangular coordinate grid to obtain a final image.

The invention discloses an ultrasonic CT-based synthetic aperture imaging method and system. The method comprises the following steps: S1, acquiring data received through ultrasonic reflection by utilizing an ultrasonic CT annular array probe, so as to obtain raw echo data; S2, conducting synthetic aperture focusing on the echo data, so as to obtain values of all imaging points; S3, rotating the ultrasonic CT annular array probe and repeating the steps S1-S2, so as to obtain a plurality of groups of imaging point values, wherein each rotating angle is smaller than an included angle between two adjacent array elements and the circle center of the annular array probe; S4, conducting weighted averaging on the imaging point values, and then carrying out envelope detection, logarithmic compression and grey mapping treatment in sequence, so as to obtain a final high-resolution image. The invention further provides the system for implementing the method. According to the method and the system, the raw data are acquired based on ultrasonic CT (UCT) in a multi-rotating manner, and such treatment measures as weighted stacking are adopted, so as to effectively reduce the influence of noise and improve the image resolution.

The invention relates to a digital synthetic aperture imaging method based on pupil modulation. The digital synthetic aperture imaging method performs functions of restoring the optical field of the pupil, correcting single-aperture aberration, realizing multi-aperture common-phase, and obtaining high-resolution image through synthesis. According to the digital synthetic aperture imaging method, the pupil plane of each imaging subsystem is modulated by means of an external diaphragm; according to different modulation information (diameter, position or size of the light through hole of the diaphragm) and a corresponding image, reconstructing the optical field of each pupil by means of a Fourier ptychography algorithm; representing phase distribution of the optical field by means of a Zernike polynomial, optimizing a pixel evaluation function by means of a digital correction method, correcting an aberration of the single aperture and aberrations between multiple apertures, and combining pupil incoming optical fields for obtaining a high-resolution image based on a digital imaging principle. According to the digital synthetic aperture imaging method, optical field reconstruction, aberration correction and image synthesizing are combined. The digital synthetic aperture imaging method has advantages of high resolution of obtained image, compact optical path, simple device structure, low cost, etc.

The present invention discloses a kind of primary and secondary satellite system with high spatial resolution and realized by means of combining interference type synthetic aperture imaging technology and antenna array rotating scan technology. The satellite system includes one primary satellite and N secondary satellites, which has position distribution relative to the primary satellite obtained by means of spatial frequency sample base line length optimizing process. The present invention has raised aperture rarefying efficiency, simplified radiation imaging instrument system, raised spatial frequency domain coverage, raised spatial resolution, stabilized combined centrifugal force and gravitational force gradient and simplified secondary satellite posture stability control.

The invention publishes a method for designing a high-efficiency sparse dictionary in synthetic aperture compressed sensing ultrasonic imaging, and belongs to the technical field of ultrasonic imaging. The method includes the following steps: performing amplification processing and A/D conversion on a continuous echo signal received by an ultrasonic array, thereby obtaining an echo signal x required by ultrasonic imaging; selecting a delta matrix as a measurement matrix of synthetic aperture compressed sensing ultrasonic imaging, and performing non-uniform compressed sampling on the echo signal x to obtain a measurement signal y; and utilizing a transmission pulse as a primary function to construct a high-efficiency sparse dictionary psi; and building a mathematical model of synthetic aperture compressed sensing ultrasonic imaging according to the delta matrix, the measurement signal y and the high-efficiency sparse dictionary , obtaining a reconstructed original echo signal x<~> through the model and a reconstruction algorithm, and utilizing the reconstructed original echo signal x<~> to perform beam composition and finally realizing imaging. The method for designing the high-efficiency sparse dictionary in synthetic aperture compressed sensing ultrasonic imaging can enable the echo signal to realize the same recovery effect with a higher compression ratio, further reduce the data volume that needs to be stored for synthetic aperture imaging and reduce the complexity of an ultrasonic imaging system.

The invention discloses a full-focus synthetic aperture perspective imaging method based on multilevel iteration visualization optimization. The technical problem that an existing pixel mark synthetic aperture imaging method based on energy minimization is bad in imaging effect is solved. The technical scheme is that a scene is firstly divided into a plurality of visible layers, an iteration method is used for designing an extensive synthetic aperture optimization frame, the surfaces of a visible object and a shielded object are rebuilt under a free depth, a multilevel iteration energy minimization optimization mode is used, and in a randomly-given depth range, a full-focus image is generated. Data of the method in a Stanford data base and a UCSD data base are detected, and the detection results show that full-focus imaging which is clear and close to reality is obtained through the method.

The invention aims to provide a multi-telescope optical synthetic aperture imaging system and a design method thereof in order to solve the problems that the conventional single large-aperture optical system is difficult to process and manufacture, and that the synthetic aperture imaging system cannot reach a desired system index in practice. The designed three-sub-telescope refractive and reflective optical synthetic aperture imaging system consists of a light beam synthesis mirror, three afocal sub telescopes which have the same structure and are arranged in a central symmetry manner on the system entrance pupil face, and optical delay lines which respectively correspond to the afocal sub telescopes; the aperture, on the light beam synthesis mirror, of the common circumcircle of the exit pupils of the three afocal sub telescopes meets the requirement of the magnifying power of the afocal sub telescopes; the optical delay lines are arranged on parallel emergent light paths of corresponding refraction systems; each of the optical delay lines consists of two planar reflecting mirrors; and the light beam synthesis mirror is a rotation symmetric system. The multi-telescope optical synthetic aperture imaging system is compact in structure and rational in layout, and lays the foundation for implementation of engineering application of the synthetic aperture imaging technology.

The invention discloses the phase filtering method and the height measuring method of a spaceborne interference imaging altimeter. The phase filtering method comprises the following steps of carryingout synthetic aperture imaging processing on the data of the two receiving channels of the spaceborne interference imaging altimeter to obtain two complex images, taking one of the images as a benchmark to register the two complex images, and calculating the coherence coefficient of the two registered images; successively calculating the geometric position, the observation angle, and the multi-view number of each pixel in the images; determining the azimuth filtering window size and the distance filter window size of each pixel, and determining the azimuth filtering interval and the distance filtering interval of each pixel; and carrying out conjugate multiplication on the two complex images, simultaneously removing a horizon phase, then, filtering each pixel in the azimuth filtering interval and the distance filtering interval, and finally acquiring the filtered interference phase. Based on the above phase filtering method, the invention also provides the height measuring method of the spaceborne interference imaging altimeter.

The invention discloses a dispersion Hartmann sensor used for optical synthetic aperture imaging system inphase detection. The sensor is composed of an interference region selected diaphragm, a dispersion element array, a lens array and a CCD camera. A number of light through holes which are corresponding to two adjacent sub-aperture edges are arranged in the interference region selected diaphragm. Each light through hole is provided with a corresponding dispersion element in the dispersion element array. Lenses which match the dispersion elements are arranged on the lens array. Groups of two adjacent sub-aperture edge beams are selected through the interference region selected diaphragm before a broadband plane wave of an optical synthetic aperture imaging system. The dispersion elements corresponding to the groups are used to disperse the beams. The beam groups form independent dispersion stripes on the sane camera target surface through the lenses at the same time. Translation errors of a number of sub-apertures are detected at the same time.

The invention discloses a millimeter wave security check cabin system and a security check method. The millimeter wave security check cabin system comprises a security check cabin, a linear array scanning unit, a mechanical scanning mechanism, a signal collecting and processing module, a control module, an imaging display module and an automatic identification module, wherein the security check cabin comprises a cabin body, an entrance and an exit; a detection area is formed in the security check cabin; the linear array scanning unit comprises a plurality of millimeter wave sources, a plurality of millimeter wave detectors and a main body; the millimeter wave sources and the millimeter wave detectors are arranged at intervals to form array structures, and the array structures are installedon the front side and the back side of the main body; the mechanical scanning mechanism can drive the linear array scanning unit to vertically move along the entrance or move between left and right along the entrance; the signal collecting and processing module is connected with the millimeter wave detectors; the control module is connected with the mechanical scanning mechanism; and the imagingdisplay module is connected with the signal collecting and processing module, the control module and the automatic identification module. The millimeter wave security check cabin system adopts a synthetic aperture imaging principle and a spare array, has a simple structure and low cost, adopts a security check cabin structure and guarantees security check fluency and the safety of security check personnel.

The invention relates to a defect detecting method of concrete. The defect detecting method of the concrete includes the following steps of sequentially transmitting large-time large-bandwidth linear frequency modulation signals at different positions of the space, receiving echo signals, compressing the broad-pulse linear frequency modulation signals in a time domain into a short time quantum, with regard to the echo signals, conducting coherent stack treatment on the echo signals at different positions according to the spatial position and the phase relation, forming equivalent a large aperture image, and identifying defects of the concrete based on the large aperture image. The defect detecting method of the concrete combines the pulse compression technology and a synthetic aperture imaging detection method, improves the signal to noise ratio and the resolution of the detection signals, and is beneficial to detection of the defects of the concrete, especially small defects.