79 results about "Aperture synthesis" patented technology

An ultrasonic transducer is provided with a distance measuring ultrasonic sensor for detecting a distance between the ultrasonic transducer and a surface of an inspection object and an inclination of the ultrasonic transducer with respect to the surface of the inspection object, to control the distance and the inclination of the ultrasonic transducer with respect to the inspection object based on information detected by the distance measuring ultrasonic sensor, and at least part of ultrasonic wave transmission/reception by the distance measuring ultrasonic sensor is performed during execution of aperture synthesis processing during which transmission/reception by the ultrasonic transducer is not performed.

The invention discloses a large-visual-field high-resolution microscopic imaging method based on optimal Hadamard codes. The large-visual-field high-resolution microscopic imaging method includes generating a required optimal Hadamard code matrix by a computer, taking an LED array as a microscope light source, displaying optimal Hadamard code patterns, shooting a series of low-resolution microscopic images of a to-be-tested sample at different illumination angles by a camera, solving the low-resolution microscopic image of the to-be-tested sample under single-angle illumination according to the optimal Hadamard code matrix, and compositing the large-visual-field low-resolution microscopic images into a large-visual-field high-resolution image by the aid of a frequency domain aperture synthesis technology. The large-visual-field high-resolution microscopic imaging method has the advantages that required exposure time of the camera can be shortened, system image collection speed can be increased, noise can be suppressed, and quality of image collected by a system can be improved.

The invention discloses a circumference SAR back projection self-focusing method based on subaperture synthesis. The method includes the steps of dividing circumference SAR full-aperture echo data into subaperture echo data, selecting a strong scattering unit in an observation scene to conduct back projection self-focusing processing based on image acutance maximization so that the phase error of each subaperture echo datum can be estimated, synthesizing the phase errors of all the subaperature echo data into the circumference SAR full-aperture echo data phase error, and finally obtaining the circumference SAR full-aperture echo data phase error so that the accurate circumference SAR back projection imaging can be conducted. Compared with an existing circumference SAR back projection self-focusing algorithm, the method has the advantages of being high in imaging accuracy and speed and is suitable for processing circumference SAR large-scene measured data.

The present invention provides a novel optical synthesis aperture imaging system based on the optical fiber array. The high-resolution image can be obtained by the imaging technique of synthesizing a plurality of small apertures to a synthesis aperture. The acquired accomplishment of optical synthesis aperture imaging in the high resolution imaging displays that the technique has a wide developing prospect. The invention receives the optical wave radiated from the target by a Cassegrain telescope array. The optical fiber is coupled in a single-mode polarization-preserving fiber for transmitting. An optical fiber collimator array is used for leading to coherent imaging of the light beam. The phase error compensation is executed through a piezoelectric ceramic phase modulator and an optical fiber delay line. The whole set of equipment goes for miniaturization and lightening, and can be applied in the fields of astronomical measurement, remote sensing the plant cover, monitoring the environment and disaster and the like.

The invention discloses a de-shielding method of a synthesized aperture of a light field camera. The method comprises steps of according to input light field information, obtaining all sub-aperture images; detecting characteristic points of all sub-aperture images; selecting a region on a center view angle image, keeping characteristic points in the selected region and abandoning characteristic points outside the selected region, wherein a shielding object and a shielded object on a target plane are arranged in the selected region; matching the characteristic points obtained in the previous step with characteristic points of the rest view angle images, and carrying out screening to obtain characteristic point pairs; through the screened out characteristic points, calculating homography transform matrixes of the center view angle image and the rest view angle images; through the homography transform matrixes, carrying out mapping on the rest view angle images; and averaging all mapped sub-aperture images so as to obtain the final sub-aperture synthesized image. According to the invention, small-size shielding objects in front of a lens can be removed and information behind the shielding object can be acquired.

The invention discloses a visibility function direct inversion method of an atmospheric temperature and humidity profile. The method comprises the following steps: inputting an actual observed visibility function into a trained BP neural network, so as to obtain an inversed atmospheric temperature and humidity profile physical parameter, wherein the training of the BP neural network comprises: using a numerical weather mode to obtain a sample atmospheric physical parameter, and using an aperture synthesis microwave radiometer model to carry out forward modeling on the sample atmospheric physical parameter to obtain a visibility function corresponding to the sample atmospheric physical parameter; and using the sample atmospheric physical parameter and the visibility function corresponding to the sample atmospheric physical parameter to train the BP neural network, so as to obtain the trained BP neural network. The invention changes a two-step inversion method of visibility-brightness temperature-atmospheric physical parameters required for remote sensing atmospheric physical parameters of a current aperture synthesis microwave radiometer, and proposes a direct inversion method of visibility-atmospheric physical parameters, which simplifies the data processing flow and reduces inversion errors, so as to obtain more accurate atmospheric physical parameters.

The invention discloses a frequency diversity array synthetic aperture three-dimensional imaging radar system and an imaging method thereof. The system is composed of a linear frequency diversity array radar and a motion platform (airplane). The array radar comprises a transmitting part and a receiving part, wherein the transmitting part comprises a baseband frequency selection unit, a baseband signal generator, an up-converter, an antenna selection unit and a transmitting antenna array which are sequentially connected; the receiving part comprises a receiving antenna array, an antenna selection unit, a filter and a down-conversion and imaging algorithm unit which are sequentially connected; a linear frequency diversity array radar is installed on the motion platform, and the motion platform is connected with an imaging algorithm unit of the linear frequency diversity array radar. Under the condition that a frequency diversity array is used by the system, aperture synthesis is combinedto complete target three-dimensional imaging. The imaging method is simple in transmitted signal form, the distance direction resolution can be obtained without pulse compression, and the distance direction image, the azimuth direction image and the pitching direction image of the target can be obtained at the same time through one-time phase compensation.

The invention aims at providing a bowl-shaped flexible three-dimensional array ultrasonic probe. The bowl-shaped flexible three-dimensional array ultrasonic probe has the advantages of locating accuracy, simple device and the like. The bowl-shaped flexible three-dimensional array ultrasonic probe comprises a bowl-shaped flexible shell, a composite piezoelectric crystal plate, a coupling agent injecting device, connecting lines and the like, wherein the bowl-shaped structure can well attach to the detected surface of a flexible body, an ultrasonic transducer adopts the multi-array-element array composite crystal plate structure, the plurality of array elements are distributed according to the Fibonacci helical line, 2n array elements compose the ultrasonic array transducer, according to the delaying sequence, each array element emits ultrasonic waves once, the other array elements including the emitting array element receive signals, and a storage records and stores the 2n signals. In combination with the phased array technology principle, the aperture synthesis technology is adopted for carrying out data after-treatment on the extracted 2n signals, and then the image reflecting the information including the position, degree and the like of the lesion tissue is obtained.

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 discloses a horizontal array motion aperture synthesis positioning method and a device therefore. The horizontal array motion aperture synthesis positioning method comprises: decomposing the underwater acoustic data collected by the array elements of a horizontal array into a plurality of time units; evaluating the phases of each narrowband time unit laminated spatially between the array elements, to obtain a phase evaluation factor, processing time delay sampling and phase compensation on the array element time units; processing aperture synthesis for the time sequence obtained by different array elements in one narrow band, to form a large aperture virtual horizontal array; according to zero point control full normal mode filter theory, processing zero point control mode filtration on the large aperture virtual horizontal array, to obtain target mode information; using the target mode information to obtain three-dimension positioning result of the target according to maximum likelihood method. The method and device can obtain high positioning accuracy, with simple and practical process. The invention can realize real-time application without much additional computing resource.

Respective regional form information items obtained from regional interference fringe images corresponding to partial regions of a spherical surface to be inspected are transformed into regional synthesis form information items corresponding to a common coordinate system set for aperture synthesis by using a relationship among a polar coordinate system of the spherical surface, a plane coordinate system of an imaging plane, and the common coordinate system. Thus obtained regional synthesis form information items are subjected to aperture synthesis processing, so as to determine the overall form information of the spherical surface.

The invention discloses methods for differencing and self-focusing phases of a synthetic aperture laser imaging radar. According to a principal, an azimuth phase signal with a noise phase is extracted from a radar echo signal subjected to range focusing and shifted, the shifted phase signal and an unshifted phase signal are differenced, a signal obtained through differencing is sequentially subjected to Fourier transformation, band-pass filtering and inversion Fourier transformation to obtain signals, the obtained signals are sampled and accumulated at equal intervals to obtain an optimized azimuth quadratic phase, and the optimized azimuth quadratic phase is subjected to azimuth focusing to image a target. By the method, quadratic phase process crucial to target aperture synthesis is optimized, so that the imaging quality can be improved; and the method is important technological improvement of the synthetic aperture laser imaging radar.

The invention discloses a high-orbit sub-aperture ISAR imaging method for a ship target, and aims at solving the problems of image defocusing and difficulty in improving the resolution due to the factthat a ship moves in long synthetic aperture time, as long as hundreds of thousands of seconds, required by high resolution imaging of a high-orbit satellite with a high orbit but relatively low running speed. On one hand, the sub-aperture synthetic aperture time is short, and influence of ship motion on imaging is reduced, and on the other hand, the rotation angle generated by ship swing is alsobeneficial to realizing high-resolution ISAR imaging. Traditional understanding that ship motion is regarded as a motion error is broken through, high-resolution ISAR imaging is carried out by utilizing the ship motion, the problem of contradiction between high-orbit long synthetic aperture time and the ship motion is solved, and the method can be applied to the fields of high-orbit ship target detection, identification and imaging.

The invention provides a high orbit SAR continuous gazing working mechanism system design method comprising the following steps: 1, designing the height, inclination angle and eccentricity of a satellite orbit according to an interested area scope; 2, combining with engineering reality and system requirements; 3, designing high orbit SAR satellite sliding window imaging work modes according to thesatellite wave beam motion speed, and designing the sliding window sizes and speed; 4, selecting the satellite networking number and designing a networking mode according to the satellite energy restrictions, thus realizing 24-hour continuous visual and imaging observation for the interested areas. The method can optimize the orbit design and double-satellite cooperation so as to shorten the aperture synthesis time, thus making up the disadvantages of the satellite power supply capability and imaging visual angle limits, and realizing the 24-hour continuous gazing imaging observation of the interested key areas.

The invention discloses a path planning method for short-time aperture synthesis of a distributed radar. The method comprises the following steps: S1, establishing a geometric model and an echo modelof the distributed radar; S2, establishing a path planning model of the distributed radar, and establishing an optimization objective; and S3, solving the optimization objective by an optimization method based on a greedy algorithm. The optimal path planning problem is established as a multi-objective optimization problem under a multi-constraint condition by analyzing the constraint relationshipin a distributed radar flight and imaging model, the objective function of each point is calculated by using the greedy algorithm, the optimal flight path is selected for the short-time synthetic aperture of the distributed radar, and the short-time high-resolution imaging effect of the distributed radar is effectively ensured.

An ultrasonic measurement device comprises a transmitting and receiving means (11, 12) and an aperture synthesis processing means (14). The transmitting and receiving means (11, 12), while allowing a focal point formed by an ultrasonic probe (10) to relatively scan a specimen, transmits an ultrasonic wave toward the specimen and receives a reflected wave from an internal defect of the specimen. The aperture synthesis processing means (14) performs aperture synthesis processing on a signal received at each measurement point using a reference transmission time which is obtained by treating the waveform of the ultrasonic wave transmitting between the ultrasonic probe and the internal defect as an ultrasonic waveform synthesized over the entire surface of a transmission and reception surface.

The invention relates to an overlapping-subaperture-based electro-optical-synergy synthetic aperture radar imaging processing method. The method comprises: step one, carrying out aperture segmentation; to be specific, carrying out aperture segmentation on SAR echo data in a synthetic aperture in an azimuth to obtain a plurality of subaperture data blocks, and carrying out phase shift pre-processing; step two, carrying out SAR data imaging processing; to be specific, modulating the subaperture data blocks to be at laser beams separately and simultaneously by using a plurality of spatial light modulators in an optical imaging module, carrying out parallel processing on the subaperture data blocks in a light domain, enabling all paths of laser beams to pass through the corresponding optical imaging modules in parallel, and completing imaging processing by the plurality of subaperture data blocks loaded on the laser beams simultaneously to obtain a plurality of low-resolution SAR images; and step three, carrying out aperture synthesis; to be specific, synthesizing the plurality of low-resolution SAR images in the light domain to obtain a high-resolution SAR image Compared with the prior art, the method has advantages of high-resolution real-time imaging, parallel optical processing, and the like.

In performing aperture synthesis according to an ultrasound imaging apparatus, the amount of spatial change of amplification factors of phasing signals at respective receive phasing points are reduced, and a high-quality image is obtained. In a receive beamformer that generates an inter-transmission weight in accordance with a phasing range, and performs aperture synthesis processing, the inter-transmission weight being generated is applied to the receive phasing points within the phasing range obtained through transmission and reception, and the inter-transmission synthesis is performed. The inter-transmission weight is generated in such a manner that a variation form of the amplification factor between adjacent receive phasing points is smoothed and a difference of the amplification factor is reduced, as to each receive phasing point after the inter-transmission synthesis is performed.

The embodiment of the invention provides an ultrasonic imaging device. The device comprises a probe circuit, a transmission module, a receiving module, a data processing module and a display/operation module. The transmission module is used for transmitting ultrasonic waves by means of two or more array elements of the probe circuit according to an operation instruction received from the display/operation module to form non-focused cylindrical waves. The receiving module is used for receiving the cylindrical waves transmitted by the transmission module by means of the probe circuit. The data processing module is used for forming a dual point-by-point focus image from the cylindrical waves received by the receiving module through aperture synthesis, and the image is displayed through the display/operation module. The power consumption of the ultrasonic imaging device can be reduced.

Disclosed is a microwave photonics based multi-channel signal transmission system for an aperture synthesis radiometer. The system comprises multi-channel receiving front ends, multi-channel optical transmitters, multi-channel optical fibers and optical receivers. The multi-channel receiving front ends receive multi-channel radio frequency microwave radiation signals through antennas, and then amplify the received signals through low-noise amplification modules. The multi-channel optical transmitters modulate the amplified radio frequency signals to light, light signals are transmitted from all the optical transmitters to the optical receivers through the multi-channel optical fibers, then the optical receivers convert the light signals into radio frequency signals to be outputted, and transmission of the multi-channel radio frequency signals of the aperture synthesis microwave radiometer is completed. By adoption of microwave photonics technology, the radio frequency signals of the distributed receiving front ends of the aperture synthesis microwave radiometer are transmitted, amplitude and phase congruency of multi-channel radio frequency transmission are improved greatly. The method is simple to implement and high in reliability, and a critical foundation is laid to future application of the aperture synthesis microwave radiometer.