CN111505637B - Self-calibration near field imaging method and system based on two-unit scanning interferometer - Google Patents
Self-calibration near field imaging method and system based on two-unit scanning interferometer Download PDFInfo
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- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
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- G01S13/89—Radar or analogous systems specially adapted for specific applications for mapping or imaging
- G01S13/90—Radar or analogous systems specially adapted for specific applications for mapping or imaging using synthetic aperture techniques, e.g. synthetic aperture radar [SAR] techniques
- G01S13/9021—SAR image post-processing techniques
- G01S13/9023—SAR image post-processing techniques combined with interferometric techniques
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
- G01S13/88—Radar or analogous systems specially adapted for specific applications
- G01S13/89—Radar or analogous systems specially adapted for specific applications for mapping or imaging
- G01S13/90—Radar or analogous systems specially adapted for specific applications for mapping or imaging using synthetic aperture techniques, e.g. synthetic aperture radar [SAR] techniques
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- G01S13/9056—Scan SAR mode
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- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
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Abstract
The invention belongs to the technical field of near-field target detection and imaging, and relates to a self-calibration near-field imaging method based on a two-unit scanning interferometer, which comprises the following steps: performing time-sharing sampling by using the two antenna units, performing complex correlation operation on sampling data received by the two receivers to obtain a visibility function value corresponding to each baseline, and generating a visibility function value set as a visibility function; performing receiver channel phase error correction and near-field phase error correction on the obtained visibility function to obtain a visibility function after the near-field error correction; based on the Fourier transform relationship between the two-dimensional brightness temperature image of the near-field observation field and the visibility function after near-field error correction, the two-dimensional brightness temperature image of the near-field observation field is taken as an input variable, the visibility function after near-field error correction is utilized, different fast inverse Fourier transform algorithms are adopted according to different antenna array configurations, image inversion is carried out, and the brightness temperature image of the near-field observation field is obtained.
Description
Technical Field
The invention belongs to the technical field of passive microwave remote sensing and near-field target detection and imaging, and particularly relates to a self-calibration near-field imaging method and a self-calibration near-field imaging system based on a two-unit scanning interferometer.
Background
An interference type synthetic aperture radiometer is one of the main technical means for realizing microwave radiation measurement in the field of passive microwave remote sensing. The system obtains the visibility function by measuring the spatial frequency domain distribution of the brightness temperature of the observation scene. And then reconstructing the brightness temperature distribution of the observation scene by utilizing the Fourier transform relation between the brightness temperature distribution of the observation scene and the visibility function. Compared with the traditional real aperture radiometer, the interferometric synthetic aperture microwave radiometer has the greatest advantages of solving the technical problems of low spatial resolution, high mechanical scanning difficulty and large volume and weight of passive microwave remote sensing, and is paid more and more attention in the field of satellite-borne earth observation. Soil Moisture and Ocean Salinity satellites (SMOS) launched by the European space agency in 2009 are the first international earth observation satellites with synthetic aperture microwave radiometers as the main load. Thereafter, for application scenarios such as ocean salinity remote sensing and stationary orbit atmospheric sounding, a plurality of new system load concepts and satellite observation plans are proposed in succession, and the related technologies are rapidly developed. Near field imaging is another important application area of interferometric synthetic aperture technology, in addition to satellite remote sensing applications. On one hand, in the ground test stage, a synthetic aperture radiometer system developed for satellite-borne application cannot meet the required far-field condition, and system imaging and partial system-level indexes are verified under the near-field condition; on the other hand, in recent years, high-resolution passive microwave near-field imaging is also urgently required for practical applications in security inspection imaging of dangerous articles hidden in human bodies, short-distance target imaging under poor visual conditions, underground embedded article detection and the like.
However, the conventional imaging algorithm based on the fourier transform is on the premise that the far-field condition is satisfied, and under the near-field condition, the imaging algorithm based on the fourier transform fails due to the near-field phase error caused by inconsistent distance differences between the antenna array and the spatial domain sampling point, so that the near-field imaging algorithm is a key problem to be solved urgently in the close-range imaging application of the synthetic aperture radiometer.
The first near-field imaging method is based on the idea that the arrangement of antennas is changed to enable a visibility function and brightness temperature distribution to meet the Fourier transform relationship, and for example, the antenna arrays in spherical distribution are used for near-field observation, so that the same visibility function expression as that under a far-field condition is obtained, and then the target brightness temperature is obtained by utilizing the Fourier transform relationship for inversion. The method has the greatest advantage that near-field observation of targets with any size can be realized, but the method limits the observation distance of the system, is only effective for the imaging result of a scene at the spherical radius distance, and has the problem that the radius length of a spherical array needs to be changed if targets at other distances are detected, which is difficult to realize in practical application.
The idea of another near field imaging method is to modify the phase of the visibility function under the near field condition on the basis of the original planar array, so that the scene brightness temperature distribution and the visibility function become an approximate Fourier transform relationship. For example, in the ground imaging test of a geostationary orbit satellite-borne millimeter wave synthetic aperture radiometer GeoSTATAR model machine developed by payload MIRAS carried on SMOS satellite of European space administration and US NASA, a near-field phase correction method is adopted to process the test data of a point source target and an extended target. When imaging experiments are carried out on an extended target, a researcher takes a certain position of the central axis of an antenna array of an imaging system as a reference point source and assumes that system detection data is caused by the point source. However, the assumption that there is a reference point source at a certain location is not theoretically supported, and the method has a large error in imaging an extended target occupying a large field of view.
Zhang Cheng et al proposed a surface focusing numerical solution based on Moore-Penrose generalized inverse, and utilized a one-dimensional antenna array to perform near-field imaging simulation and external field test on a point source and an extended target. However, this method is high in computational complexity and poor in computational efficiency for inversion of a two-dimensional antenna array.
Chenjian Fei et al propose a regularization synthetic aperture near-field imaging algorithm based on a G matrix and perform a simulation experiment aiming at a one-dimensional and two-dimensional antenna array. Compared with the FFT algorithm, the regularization G matrix method has relatively small imaging error, because the method directly utilizes the regularization method to process the original visual degree function sampling data and does not need interpolation. However, this method also has a problem of a large amount of calculation and computation.
Yao gao et al propose a near-field image inversion algorithm based on partial differential equation of local self-adaptation, the basic principle of this algorithm is to adopt different algorithms according to the local characteristic of the bright temperature picture of the original scene, adopt isotropic diffusion to inhibit the noise of the background area, adopt the detailed information of edge in the diffusion holding target area of self-adaptation, this scheme can reduce the influence of noise included in the measurement process of the visual degree function to the image inversion effectively. However, the method still does not achieve the purpose of fast imaging of the two-dimensional antenna array.
In the application of the comprehensive aperture radiometer at home and abroad, the two-dimensional antenna array is more and more widely used, but the near-field imaging methods at the present stage all have the defects of low imaging speed and high calculation complexity.
The binary interferometer is the minimum component unit of an interferometric synthetic aperture microwave radiometer system, can form various array configurations and corresponding baseline combined sampling coverage through binary time-sharing sampling, and can be used for prototype verification of a near-field imaging system and an algorithm. The existing near-field imaging method is an error integral correction method based on a reference point source, and the method can obtain correction information of a near-field phase by carrying out actual auxiliary measurement on the reference point source at the center of a target plane under the condition that distance information is unknown, so that the calibration of the phase error of a receiving channel of a system is completed simultaneously. The visibility function obtained by directly detecting the small sun by the two-unit interferometer is VF, and the visibility function obtained by directly detecting the point source target at the center of the view field under the condition of the same observation distanceThe visibility function is VF0Then, the visibility function VF' corrected by the method is:
however, in the target detection process for different observation distances, the method needs to image the central point source of the field of view besides the primary imaging of the target, and the test process is complicated.
For a two-element scanning interferometer, all the visibility functions are obtained by time-sharing sampling of two receivers, and the phase difference between the two channels causes all the visibility functions to have the same phase error term. The existing near-field imaging method is a near-field imaging method based on a reference point source, and cannot solve the technical problem of phase errors of the two-unit scanning interferometer.
Disclosure of Invention
The invention aims to solve the defects in the prior art, and provides a self-calibration near field imaging method based on a two-unit scanning interferometer, which is a self-calibration near field imaging method for correcting a receiver channel phase error and a near field phase error step by step.
The invention provides a self-calibration near field imaging method based on a two-unit scanning interferometer, wherein the two-unit scanning interferometer generates different base lines by utilizing the movement of sliding carriages placed in the horizontal direction and the vertical direction on corresponding sliding carriages, and all the base lines form a lattice distributed in a grid and are equivalent to an antenna array configuration; the method comprises the following steps:
performing time-sharing sampling by using the two antenna units, performing complex correlation operation on sampling data received by the two receivers to obtain a visibility function value corresponding to each baseline, and generating a visibility function value set as a visibility function;
performing receiver channel phase error correction and near-field phase error correction on the obtained visibility function to obtain a visibility function after the near-field error correction;
based on the Fourier transform relationship between the two-dimensional brightness temperature image of the near-field observation field and the visibility function after near-field error correction, the two-dimensional brightness temperature image of the near-field observation field is taken as an input variable, the visibility function after near-field error correction is utilized, different fast inverse Fourier transform algorithms are adopted according to different antenna array configurations, image inversion is carried out, and the brightness temperature image of the near-field observation field is obtained.
As an improvement of the above technical solution, the two antenna units are used for performing time-sharing sampling, and the sampled data received by the two receivers are subjected to complex correlation operation to obtain a visibility function value corresponding to each baseline, so as to generate a visibility function value set as a visibility function; the method specifically comprises the following steps:
carrying out complex correlation operation on sampling data received by two receivers in the two-unit scanning interferometer:
wherein, V12Performing complex correlation operation on the sampling data received by the two receivers at the time t to obtain a visibility function value corresponding to the baseline; e1(d1T) is sampled data received by one of the receivers; e2(d2T) is sampled data received by another receiver; d1The linear distance from a spatial domain sampling point to one antenna unit is obtained; d2The linear distance from a spatial domain sampling point to another antenna unit is obtained; wherein the sampling data is radiation field intensity;
the method comprises the steps of obtaining different baselines and corresponding visibility function values according to time-sharing sampling of two antenna units in a two-unit scanning interferometer, summarizing the visibility function values corresponding to each baseline, generating a visibility function value set, using the visibility function value set as a visibility function VF, and storing the visibility function value set.
As one improvement of the above technical solution, the obtained visibility function is subjected to receiver channel phase error correction and near-field phase error correction to obtain a corrected visibility function of a near-field error; the method specifically comprises the following steps:
and performing receiver channel phase error correction on the obtained visibility function to obtain the visibility function after the receiver channel phase error correction:
VF1＝VF·e-j·A (1)
wherein, A is the phase error of the receiver channel; j is an imaginary unit; e.g. of the type-j·AIs a channel phase error compensation factor; VF (variable frequency)1Is a visibility function corrected by the phase error of the receiver channel;
for visibility function VF corrected by phase error of receiver channel1And performing near-field phase error correction to obtain a visibility function after the near-field phase error correction:
therein, VF2Is a visibility function corrected by near-field phase error; VF'0Target visibility function data of a point source at the center of a view field; angle (VF'0) Is VF'0The phase of (d);
wherein, the target visibility function data of the central point source of the field of view is a set of visibility function values corresponding to all baselines obtained by the two-unit scanning interferometer in the scanning process of observing a scene by the central point source of the field of view, namely V12(u, v) set; wherein, V12(u, v) the formula is:
wherein, TB(xi, eta) is the brightness temperature value of the point source target at the center of the view field; (ξ, η) are the directional cosine coordinates:
wherein, θ and
the angle value of a point source target scene pixel point observed from the antenna array under the spherical coordinate system; (u, v) is the spatial frequency domain coordinate system in which the baseline is located.
As one improvement of the above technical solution, the antenna array is configured as a motion track formed by the movement of the antenna units respectively placed on the carriages in the horizontal and vertical directions on the corresponding carriages; it includes: an open-loop two-dimensional antenna array and a closed-loop two-dimensional antenna array;
wherein the open loop two-dimensional antenna array comprises: the antenna comprises a Y-shaped two-dimensional antenna array, a U-shaped two-dimensional antenna array and a T-shaped two-dimensional antenna array;
the closed-loop two-dimensional antenna array comprises: a circular two-dimensional antenna array, a hexagonal two-dimensional antenna array, and a square two-dimensional antenna array.
As one improvement of the above technical solution, image inversion is performed by adopting different fast inverse fourier transform algorithms according to different antenna array configurations to obtain a bright temperature image of a near-field observation field; the method specifically comprises the following steps:
for the T-shaped two-dimensional antenna array, the square two-dimensional antenna array and the U-shaped two-dimensional antenna array, sampling points in a spatial frequency domain are distributed in a rectangular grid, and an IFFT algorithm is directly adopted to perform image inversion to obtain a brightness temperature image of a near-field observation field;
for the Y-shaped two-dimensional antenna array and the hexagonal two-dimensional antenna array, the sampling points of the spatial frequency domain are distributed in a hexagonal grid, and the image inversion is directly carried out by adopting a hexagonal IFFT algorithm to obtain a bright temperature image of a near-field observation field;
for the circular two-dimensional antenna array, the spatial frequency domain sampling points are distributed in a circular grid, and a pseudo-polar grid inverse Fourier algorithm is adopted to perform image inversion to obtain a bright temperature image of a near-field observation field.
The invention also provides a self-calibration near-field imaging system based on the two-unit scanning interferometer, which comprises: the device comprises a two-unit scanning interferometer, a sliding frame arranged in the horizontal direction and the vertical direction, and a visibility function acquisition module, a visibility function correction module and an image inversion module which are arranged on an upper computer; the method comprises the following steps that two receivers in a two-unit scanning interferometer which is placed on a sliding frame in the horizontal direction and the vertical direction move on the corresponding sliding frame to generate different base lines, and all the base lines form a lattice distributed in a grid and are equivalent to an antenna array configuration;
the visibility function acquisition module is used for performing time-sharing sampling by using the two antenna units, performing complex correlation operation on sampling data received by the two receivers to obtain a visibility function value corresponding to each baseline, generating a visibility function value set and obtaining a visibility function;
the visibility function correction module is used for performing receiver channel phase error correction and near-field phase error correction on the obtained visibility function to obtain a corrected visibility function of a near-field error;
the image inversion module is used for performing image inversion based on a Fourier transform relationship between the two-dimensional brightness temperature image of the near-field to-be-observed view field and the near-field error corrected visibility function by taking the two-dimensional brightness temperature image of the near-field to-be-observed view field as an input variable and adopting different fast inverse Fourier transform algorithms according to different antenna array configurations and obtaining the brightness temperature image of the near-field observation view field.
As an improvement of the above technical solution, the visibility function obtaining module is configured to perform time-sharing sampling by using two antenna units, perform complex correlation operation on sampling data received by two receivers, obtain a visibility function value corresponding to each baseline, generate a visibility function value set, and obtain a visibility function; the specific process comprises the following steps:
carrying out complex correlation operation on sampling data received by two receivers in the two-unit scanning interferometer:
wherein, V12Performing complex correlation operation on the sampling data received by the two receivers at the time t to obtain a visibility function value corresponding to the baseline; e1(d1T) is sampled data received by one of the receivers; e2(d2T) is sampled data received by another receiver; d1The linear distance from a spatial domain sampling point to one antenna unit is obtained; d2The linear distance from a spatial domain sampling point to another antenna unit is obtained; wherein the sampling data is radiation field intensity;
the method comprises the steps of obtaining different baselines and corresponding visibility function values according to time-sharing sampling of two antenna units in a two-unit scanning interferometer, summarizing the visibility function values corresponding to each baseline, generating a visibility function value set, using the visibility function value set as a visibility function VF, and storing the visibility function value set.
As an improvement of the above technical solution, the visibility function correction module is configured to perform receiver channel phase error correction and near-field phase error correction on the obtained visibility function to obtain a visibility function after near-field error correction; the specific process comprises the following steps:
and performing receiver channel phase error correction on the obtained visibility function to obtain the visibility function after the receiver channel phase error correction:
VF1＝VF·e-j·A (1)
wherein, A is the phase error of the receiver channel; j is an imaginary unit; e.g. of the type-j·AIs a channel phase error compensation factor; VF (variable frequency)1Is a signal via a receiverA visibility function after channel phase error correction;
for visibility function VF corrected by phase error of receiver channel1And performing near-field phase error correction to obtain a visibility function after the near-field phase error correction:
therein, VF2Is a visibility function corrected by near-field phase error; VF'0Target visibility function data of a point source at the center of a view field; angle (VF'0) Is VF'0The phase of (d);
wherein, the target visibility function data of the central point source of the field of view is a set of visibility function values corresponding to all baselines obtained by the two-unit scanning interferometer in the scanning process of observing a scene by the central point source of the field of view, namely V12(u, v) set; wherein, V12(u, v) the formula is:
wherein, TB(xi, eta) is the brightness temperature value of the point source target at the center of the view field; (xi, η) is the direction cosine coordinate:
wherein, θ and
the angle value of a point source target scene pixel point observed from the antenna array under the spherical coordinate system; (u, v) is the spatial frequency domain coordinate system in which the baseline is located.
As one improvement of the above technical solution, the antenna array is configured as a motion track formed by the movement of the antenna units respectively placed on the carriages in the horizontal and vertical directions on the corresponding carriages; it includes: an open-loop two-dimensional antenna array and a closed-loop two-dimensional antenna array;
wherein the open loop two-dimensional antenna array comprises: the antenna comprises a Y-shaped two-dimensional antenna array, a U-shaped two-dimensional antenna array and a T-shaped two-dimensional antenna array;
the closed-loop two-dimensional antenna array comprises: a circular two-dimensional antenna array, a hexagonal two-dimensional antenna array, and a square two-dimensional antenna array.
As one improvement of the above technical solution, image inversion is performed by adopting different fast inverse fourier transform algorithms according to different antenna array configurations to obtain a bright temperature image of a near-field observation field; the method specifically comprises the following steps:
for the T-shaped two-dimensional antenna array, the square two-dimensional antenna array and the U-shaped two-dimensional antenna array, sampling points in a spatial frequency domain are distributed in a rectangular grid, and an IFFT algorithm is directly adopted to perform image inversion to obtain a brightness temperature image of a near-field observation field;
for the Y-shaped two-dimensional antenna array and the hexagonal two-dimensional antenna array, the sampling points of the spatial frequency domain are distributed in a hexagonal grid, and the image inversion is directly carried out by adopting a hexagonal IFFT algorithm to obtain a bright temperature image of a near-field observation field;
for the circular two-dimensional antenna array, the spatial frequency domain sampling points are distributed in a circular grid, and a pseudo-polar grid inverse Fourier algorithm is adopted to perform image inversion to obtain a bright temperature image of a near-field observation field.
Compared with the prior art, the invention has the beneficial effects that:
(1) the imaging speed is high, FFT imaging can be utilized, the calculation complexity is low, the ill-conditioned performance can not occur like an inversion method based on a G matrix, and the method is suitable for high-speed video imaging.
(2) Compared with a G matrix method, the method has the advantages that the specific space three-dimensional distribution information of the target does not need to be known, and only the distance information from the target to the center of the array needs to be known; compared with an imaging method based on a reference point source, the method does not need secondary imaging on the reference point source, and can greatly simplify the steps of a near-field target detection test.
Drawings
FIG. 1 is a schematic diagram of data acquisition principle of center point source target visibility function data in a self-calibration near-field imaging method based on a two-unit scanning interferometer of the present invention;
FIG. 2 is a schematic phase diagram of a visibility function obtained from a near field detection test of a two-unit scanning interferometer on a target of a heater in a darkroom in an embodiment of a self-calibration near field imaging method based on a two-unit scanning interferometer according to the present invention;
FIG. 3 is a diagram illustrating the target imaging result of direct bright temperature reconstruction based on the visibility function obtained from the near field detection test in an embodiment of the self-calibration near field imaging method based on the two-unit scanning interferometer of the present invention shown in FIG. 2;
FIG. 4 is a schematic phase diagram of a visibility function corrected by a receiver channel phase error in a self-calibration near-field imaging method based on a two-unit scanning interferometer according to the present invention;
FIG. 5 is a schematic phase diagram of a visibility function after correction of a near-field phase error in a self-calibration near-field imaging method based on a two-unit scanning interferometer according to the present invention;
FIG. 6 is a schematic diagram of a target brightness temperature image obtained by inverting a two-dimensional brightness temperature image of a near-field to-be-observed field of view by using a visibility function after near-field error correction in a self-calibration near-field imaging method based on a two-unit scanning interferometer according to the present invention;
FIG. 7 is a flow chart of a self-calibration near-field imaging method based on a two-unit scanning interferometer of the present invention.
Detailed Description
The invention will now be further described with reference to the accompanying drawings.
The invention provides a self-calibration near field imaging method based on a two-unit scanning interferometer, which aims at the near field detection of the two-unit scanning interferometer; the existing imaging method is a near field imaging method based on a reference point source, and can simultaneously calibrate a near field phase error and a system receiving channel error under the condition that an observation distance is unknown, but in the existing method, in the process of detecting targets with different distances, the reference point source needs to be imaged again besides the primary detection of the targets, and the test process is complicated. Aiming at the technical problem, the invention provides a self-calibration near field imaging method for correcting the phase error of a system channel and the near field phase error step by step, which is based on the Fourier transform relationship between a two-dimensional brightness temperature image of a field to be observed in a near field and visibility function data after the near field error correction, takes the two-dimensional brightness temperature image of the field to be observed in the near field as an input variable, utilizes the visibility function after the near field error correction, and adopts a fast inverse Fourier transform algorithm to invert the target brightness temperature.
The invention provides a self-calibration near field imaging method based on a two-unit scanning interferometer, as shown in FIG. 7, the method comprises the following steps:
performing complex correlation operation on sampling data received by two receivers in the two-unit scanning interferometer to obtain a visibility function value corresponding to a baseline, and obtaining and storing the visibility function according to time-sharing sampling of two antenna units in the two-unit scanning interferometer;
specifically, the complex correlation operation is performed on the sampling data received by two receivers in the two-unit scanning interferometer:
wherein, V12Performing complex correlation operation on the sampling data received by the two receivers at the time t to obtain a visibility function value corresponding to the baseline; e1(d1T) is sampled data received by one of the receivers; e2(d2T) is sampled data received by another receiver; d1The linear distance from a spatial domain sampling point to one antenna unit is obtained; d2The linear distance from a spatial domain sampling point to another antenna unit is obtained; wherein the sampling data is radiation field intensity;
the method comprises the steps of obtaining different baselines and corresponding visibility function values according to time-sharing sampling of two antenna units in a two-unit scanning interferometer, summarizing the visibility function values corresponding to each baseline, generating a visibility function value set, using the visibility function value set as a visibility function VF, and storing the visibility function value set.
Performing receiver channel phase error correction and near-field phase error correction on the obtained visibility function to obtain a visibility function after the near-field error correction;
specifically, the phase error of the receiver channel is corrected for the obtained visibility function, and the visibility function after the phase error correction of the receiver channel is obtained:
VF1＝VF·e-j·A (1)
wherein, A is the phase error of the receiver channel; j is an imaginary unit; e.g. of the type-j·AIs a channel phase error compensation factor; VF (variable frequency)1Is a visibility function corrected by the phase error of the receiver channel; VF is a visibility function;
due to the visibility function VF corrected by the phase error of the receiver channel1There is still a near-field phase error, so it is necessary to utilize the visibility function data VF 'of the target of the center point source of the field of view obtained by the near-field imaging simulation experiment on the target of the center point source of the field of view'0For the visibility function VF corrected by the phase error of the receiver channel1And performing near-field phase error correction to obtain a visibility function after the near-field phase error correction:
therein, VF2Is a visibility function corrected by near-field phase error; VF'0Target visibility function data of a point source at the center of a view field; angle (VF'0) Is VF'0The phase of (d);
wherein, the data acquisition principle of the target visibility function data of the center point source is as shown in figure 1, the scene plane where the target of the center point source of the view field is positioned is parallel to the antenna plane where the two antenna units of the antenna 1 and the antenna 2 are positioned,TB(xi, eta) is the brightness temperature of the point source target at the center of the view field; (xi, η) is a direction cosine coordinate; wherein the content of the first and second substances,
wherein, θ and
the angle value of a point source target scene pixel point observed from the antenna array under the spherical coordinate system; (u, v) is the spatial frequency domain coordinate system in which the baseline is located. Performing complex correlation operation on the two antenna units to obtain a visibility function value V corresponding to a baseline12(u, v); wherein (u, v) is a spatial frequency domain coordinate system where the baseline is located.
Based on the principle, Matlab software is utilized to construct an antenna array configuration, the corresponding spatial frequency domain coverage shape is the same as the baseline coverage shape obtained by the two-unit scanning interferometer, and under the condition of temporarily not considering the influence of antenna directional diagram errors and the known target observation distance, the single baseline detects the visibility function value V obtained by the scene plane where the point source target is located in the center of the whole view field12(u, v) is expressed as:
wherein, VF'0The method is characterized in that in the scanning process of the two-unit interferometer for observing a scene from a central point source of the field of view, a set of visibility function values corresponding to all baselines, namely V12(u, v).
Based on the Fourier transform relationship between the two-dimensional brightness temperature image of the near-field to be observed and the visibility function after the near-field error correction, the visibility function VF after the near-field error correction is utilized2And performing image inversion by adopting different fast inverse Fourier transform algorithms according to different antenna array configurations to obtain a bright temperature image of the near-field observation field.
Wherein the different antenna array configurations comprise: an open-loop two-dimensional antenna array and a closed-loop two-dimensional antenna array;
wherein the open loop two-dimensional antenna array comprises: the antenna comprises a Y-shaped two-dimensional antenna array, a U-shaped two-dimensional antenna array and a T-shaped two-dimensional antenna array;
the closed-loop two-dimensional antenna array comprises: a circular two-dimensional antenna array, a hexagonal two-dimensional antenna array, and a square two-dimensional antenna array.
For the T-shaped two-dimensional antenna array, the square two-dimensional antenna array and the U-shaped two-dimensional antenna array, sampling points in a spatial frequency domain are distributed in a rectangular grid, and an IFFT algorithm is directly adopted to perform image inversion to obtain a brightness temperature image of a near-field observation field;
for the Y-shaped two-dimensional antenna array and the hexagonal two-dimensional antenna array, the sampling points of the spatial frequency domain are distributed in a hexagonal grid, and the image inversion is directly carried out by adopting a hexagonal IFFT algorithm to obtain a bright temperature image of a near-field observation field;
for the circular two-dimensional antenna array, the spatial frequency domain sampling points are distributed in a circular grid, and a pseudo-polar grid inverse Fourier algorithm is adopted to perform image inversion to obtain a bright temperature image of a near-field observation field.
The invention also provides a self-calibration near-field imaging system based on the two-unit scanning interferometer, which comprises: the device comprises a two-unit scanning interferometer, a sliding frame arranged in the horizontal direction and the vertical direction, and a visibility function acquisition module, a visibility function correction module and an image inversion module which are arranged on an upper computer; the method comprises the following steps that two receivers in a two-unit scanning interferometer which is placed on a sliding frame in the horizontal direction and the vertical direction move on the corresponding sliding frame to generate different base lines, and all the base lines form a lattice distributed in a grid and are equivalent to an antenna array configuration;
the visibility function acquisition module is used for carrying out time-sharing sampling by utilizing the two antenna units, carrying out complex correlation operation on sampling data received by the two receivers to obtain a visibility function value corresponding to each baseline, generating a visibility function value set and obtaining a visibility function;
the specific process comprises the following steps:
carrying out complex correlation operation on sampling data received by two receivers in the two-unit scanning interferometer:
wherein, V12Performing complex correlation operation on the sampling data received by the two receivers at the time t to obtain a visibility function value corresponding to the baseline; e1(d1T) is sampled data received by one of the receivers; e2(d2T) is sampled data received by another receiver; d1The linear distance from a spatial domain sampling point to one antenna unit is obtained; d2The linear distance from a spatial domain sampling point to another antenna unit is obtained; wherein the sampling data is radiation field intensity;
the method comprises the steps of obtaining different baselines and corresponding visibility function values according to time-sharing sampling of two antenna units in a two-unit scanning interferometer, summarizing the visibility function values corresponding to each baseline, generating a visibility function value set, using the visibility function value set as a visibility function VF, and storing the visibility function value set.
The visibility function correction module is used for performing receiver channel phase error correction and near-field phase error correction on the obtained visibility function to obtain a corrected visibility function of a near-field error;
the specific process comprises the following steps:
and performing receiver channel phase error correction on the obtained visibility function to obtain the visibility function after the receiver channel phase error correction:
VF1＝VF·e-j·A (1)
wherein, A is the phase error of the receiver channel; j is an imaginary unit; e.g. of the type-j·AIs a channel phase error compensation factor; VF (variable frequency)1Is a visibility function corrected by the phase error of the receiver channel;
for visibility function VF corrected by phase error of receiver channel1And performing near-field phase error correction to obtain a visibility function after the near-field phase error correction:
therein, VF2Is a visibility function corrected by near-field phase error; VF (variable frequency)0' is the visibility function data of the point source target at the center of the field of view; angle (VF'0) Is VF'0The phase of (d);
wherein, the target visibility function data of the central point source of the field of view is a set of visibility function values corresponding to all baselines obtained by the two-unit scanning interferometer in the scanning process of observing a scene by the central point source of the field of view, namely V12(u, v) set; wherein, V12(u, v) the formula is:
wherein, TB(xi, eta) is the brightness temperature value of the point source target at the center of the view field; (xi, η) is the direction cosine coordinate:
wherein, θ and
the angle value of a point source target scene pixel point observed from the antenna array under the spherical coordinate system; (u, v) is the spatial frequency domain coordinate system in which the baseline is located.
The image inversion module is used for performing image inversion based on a Fourier transform relationship between the two-dimensional brightness temperature image of the near-field to-be-observed view field and the near-field error corrected visibility function by taking the two-dimensional brightness temperature image of the near-field to-be-observed view field as an input variable and adopting different fast inverse Fourier transform algorithms according to different antenna array configurations and obtaining the brightness temperature image of the near-field observation view field.
The antenna array is configured into a motion track formed by the movement of antenna units respectively placed on the horizontal and vertical carriages on the corresponding carriages; it includes: an open-loop two-dimensional antenna array and a closed-loop two-dimensional antenna array;
wherein the open loop two-dimensional antenna array comprises: the antenna comprises a Y-shaped two-dimensional antenna array, a U-shaped two-dimensional antenna array and a T-shaped two-dimensional antenna array;
the closed-loop two-dimensional antenna array comprises: a circular two-dimensional antenna array, a hexagonal two-dimensional antenna array, and a square two-dimensional antenna array.
As one improvement of the above technical solution, image inversion is performed by adopting different fast inverse fourier transform algorithms according to different antenna array configurations to obtain a bright temperature image of a near-field observation field; the method specifically comprises the following steps:
for the T-shaped two-dimensional antenna array, the square two-dimensional antenna array and the U-shaped two-dimensional antenna array, sampling points in a spatial frequency domain are distributed in a rectangular grid, and an IFFT algorithm is directly adopted to perform image inversion to obtain a brightness temperature image of a near-field observation field;
for the Y-shaped two-dimensional antenna array and the hexagonal two-dimensional antenna array, the sampling points of the spatial frequency domain are distributed in a hexagonal grid, and the image inversion is directly carried out by adopting a hexagonal IFFT algorithm to obtain a bright temperature image of a near-field observation field;
for the circular two-dimensional antenna array, the spatial frequency domain sampling points are distributed in a circular grid, and a pseudo-polar grid inverse Fourier algorithm is adopted to perform image inversion to obtain a bright temperature image of a near-field observation field.
Example 1.
The two-element scanning interferometer in this example uses the movement of the receiver on the carriage in both the horizontal and vertical directions to generate different baselines, all of which form a rectangular grid distributed lattice, equivalent to the sampling effect of a T-shaped antenna array.
Next, a near-field target imaging test was performed using the two-element interferometer. The two-unit interferometer is used for detecting a small sun (heater) with an observation distance of 5.5m in a darkroom, the two receivers are used for carrying out complex correlation operation on sampling data received by the two antenna units, a visibility function VF containing visibility function values corresponding to different baselines is obtained, and the phase position of the VF corresponding to the v being 0 is shown in fig. 2. The result of reconstructing a bright temperature image based on the visibility function VF is shown in fig. 3.
As is apparent from fig. 2, due to the existence of the receiver channel phase error and the near-field phase error, the phase of the visibility function obtained by detection of the heater under the near-field condition has a certain offset at the shortest baseline and does not satisfy the conjugate symmetry relationship; therefore, the result of reconstructing the bright temperature image shown in fig. 3 is not ideal.
The phase approximation of the visibility function at the shortest base line is taken as the phase error of the receiver channel, namely A is approximately-1.496 and VF1＝VF·e-j-AThe corrected visibility function phase is shown in fig. 4. As can be seen from a comparison of the results of fig. 2 and 4, the phase of the visibility function after the channel phase error correction approaches 0 at (u, v) — (0, 0).
Constructing a T-shaped antenna array by using Matlab software, enabling the corresponding spatial frequency domain coverage shape to be the same as the coverage shape of a base line acquired by a two-unit scanning interferometer, and taking a point source target at the center of a view field as a detection target under the condition of temporarily not considering the influence of antenna directional diagram errors and the known observation distance of 5.5m, wherein the single base line has a visibility function value V of the whole observation field obtained by detection12(u, v) is expressed as:
VF′0is the data of the visibility function of the target point source of the field of view, namely the set of the visibility function values corresponding to all baselines, namely V, obtained in the scanning process of the two-unit interferometer to the observation scene of the central point source of the field of view12(u, v) set;
target visibility function data VF based on center point source of view field0', according to:
for VF1Performing near-field phase error correction to obtain near-field phase error corrected visibility function VF2The corrected phase of the visibility function, as shown in fig. 5, at this time, the phase of the visibility function corrected by the near-field phase error approximately satisfies the conjugate symmetry relationship.
Since the baseline distribution in this example is a rectangular grid distribution, the IFFT algorithm can be directly used to correct the near-field error-corrected visibility function VF2And performing image inversion to obtain a bright temperature image of the near-field observation field, wherein the result of the reconstructed bright temperature image is shown in fig. 6.
Comparing the figure 6 with the direct imaging result figure 3, it can be found that the outline and the shape of the detected target-small sun are clearer and more distinguishable, so that the effectiveness of the self-calibration near-field imaging method is verified, and the method has the advantages of simple operation, high imaging speed and low calculation complexity.
The two-unit interferometer is the minimum component unit of the interferometric synthetic aperture microwave radiometer system, can form a base line combination covered in a certain range through binary time-sharing sampling, and can be used for prototype verification of a near-field imaging system and an algorithm. In the existing error integral correction method based on the reference point source, in the target detection process aiming at different observation distances, the target is imaged once, and the central point source of the visual field is also imaged, so that the test process is complicated. The self-calibration near-field imaging method provided by the invention avoids the imaging test of a reference point source, is simple to operate, can greatly simplify the test steps, has high imaging speed, can utilize IFFT imaging, has low computational complexity, does not have ill-condition like an inversion method based on a G matrix, and is suitable for high-speed video imaging.
Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and are not limited. Although the present invention has been described in detail with reference to the embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (8)
1. A self-calibration near field imaging method based on a two-unit scanning interferometer, wherein the two-unit scanning interferometer generates different base lines by utilizing the movement of a sliding frame arranged in the horizontal direction and the vertical direction on the corresponding sliding frame, and all the base lines form a lattice distributed in a grid and are equivalent to an antenna array configuration; the method is characterized by comprising the following steps:
performing time-sharing sampling by using the two antenna units, performing complex correlation operation on sampling data received by the two receivers to obtain a visibility function value corresponding to each baseline, and generating a visibility function value set as a visibility function;
performing receiver channel phase error correction and near-field phase error correction on the obtained visibility function to obtain a visibility function after the near-field error correction;
specifically, the phase error of the receiver channel is corrected for the obtained visibility function, and the visibility function after the phase error correction of the receiver channel is obtained:
VF1＝VF·e-j·A (1)
wherein, A is the phase error of the receiver channel; j is an imaginary unit; e.g. of the type-j·AIs a channel phase error compensation factor; VF (variable frequency)1Is a visibility function corrected by the phase error of the receiver channel;
for visibility function VF corrected by phase error of receiver channel1And performing near-field phase error correction to obtain a visibility function after the near-field phase error correction:
therein, VF2Is a visibility function corrected by near-field phase error;VF′0target visibility function data of a point source at the center of a view field; angle (VF'0) Is VF'0The phase of (d);
wherein, the target visibility function data of the central point source of the field of view is a set of visibility function values corresponding to all baselines obtained by the two-unit scanning interferometer in the scanning process of observing a scene by the central point source of the field of view, namely V12(u, v) set; wherein, V12(u, v) the formula is:
wherein, TB(xi, eta) is the brightness temperature value of the point source target at the center of the view field; (xi, η) is the direction cosine coordinate:
wherein, θ and
the angle value of a point source target scene pixel point observed from the antenna array under the spherical coordinate system; (u, v) is a spatial frequency domain coordinate system in which the baseline is located;
based on the Fourier transform relationship between the two-dimensional brightness temperature image of the near-field observation field and the visibility function after near-field error correction, the two-dimensional brightness temperature image of the near-field observation field is taken as an input variable, the visibility function after near-field error correction is utilized, different fast inverse Fourier transform algorithms are adopted according to different antenna array configurations, image inversion is carried out, and the brightness temperature image of the near-field observation field is obtained.
2. The self-calibration near-field imaging method based on the two-element scanning interferometer according to claim 1, wherein the two antenna elements are used for time-sharing sampling, sampling data received by the two receivers are subjected to complex correlation operation, a visibility function value corresponding to each baseline is obtained, and a visibility function value set is generated to serve as the visibility function; the method specifically comprises the following steps:
carrying out complex correlation operation on sampling data received by two receivers in the two-unit scanning interferometer:
wherein, V12Performing complex correlation operation on the sampling data received by the two receivers at the time t to obtain a visibility function value corresponding to the baseline; e1(d1T) is sampled data received by one of the receivers; e2(d2T) is sampled data received by another receiver; d1The linear distance from a spatial domain sampling point to one antenna unit is obtained; d2The linear distance from a spatial domain sampling point to another antenna unit is obtained; wherein the sampling data is radiation field intensity;
the method comprises the steps of obtaining different baselines and corresponding visibility function values according to time-sharing sampling of two antenna units in a two-unit scanning interferometer, summarizing the visibility function values corresponding to each baseline, generating a visibility function value set, using the visibility function value set as a visibility function VF, and storing the visibility function value set.
3. The two-unit scanning interferometer-based self-calibration near-field imaging method of claim 1, wherein the antenna array is configured as a motion trajectory formed by the movement of antenna units on corresponding carriages respectively placed on the carriages in both horizontal and vertical directions; it includes: an open-loop two-dimensional antenna array and a closed-loop two-dimensional antenna array;
wherein the open loop two-dimensional antenna array comprises: the antenna comprises a Y-shaped two-dimensional antenna array, a U-shaped two-dimensional antenna array and a T-shaped two-dimensional antenna array;
the closed-loop two-dimensional antenna array comprises: a circular two-dimensional antenna array, a hexagonal two-dimensional antenna array, and a square two-dimensional antenna array.
4. The self-calibration near-field imaging method based on the two-unit scanning interferometer according to claim 3, wherein image inversion is performed by adopting different fast inverse Fourier transform algorithms according to different antenna array configurations to obtain a bright temperature image of a near-field observation field of view; the method specifically comprises the following steps:
for the T-shaped two-dimensional antenna array, the square two-dimensional antenna array and the U-shaped two-dimensional antenna array, sampling points in a spatial frequency domain are distributed in a rectangular grid, and an IFFT algorithm is directly adopted to perform image inversion to obtain a brightness temperature image of a near-field observation field;
for the Y-shaped two-dimensional antenna array and the hexagonal two-dimensional antenna array, the sampling points of the spatial frequency domain are distributed in a hexagonal grid, and the image inversion is directly carried out by adopting a hexagonal IFFT algorithm to obtain a bright temperature image of a near-field observation field;
for the circular two-dimensional antenna array, the spatial frequency domain sampling points are distributed in a circular grid, and a pseudo-polar grid inverse Fourier algorithm is adopted to perform image inversion to obtain a bright temperature image of a near-field observation field.
5. A self-calibrating near field imaging system based on a two-element scanning interferometer, the system comprising: the device comprises a two-unit scanning interferometer, a sliding frame arranged in the horizontal direction and the vertical direction, and a visibility function acquisition module, a visibility function correction module and an image inversion module which are arranged on an upper computer; the method comprises the following steps that two receivers in a two-unit scanning interferometer which is placed on a sliding frame in the horizontal direction and the vertical direction move on the corresponding sliding frame to generate different base lines, and all the base lines form a lattice distributed in a grid and are equivalent to an antenna array configuration;
the visibility function acquisition module is used for performing time-sharing sampling by using the two antenna units, performing complex correlation operation on sampling data received by the two receivers to obtain a visibility function value corresponding to each baseline, generating a visibility function value set and obtaining a visibility function;
the visibility function correction module is used for performing receiver channel phase error correction and near-field phase error correction on the obtained visibility function to obtain a corrected visibility function of a near-field error;
specifically, the phase error of the receiver channel is corrected for the obtained visibility function, and the visibility function after the phase error correction of the receiver channel is obtained:
VF1＝VF·e-j·A (1)
wherein, A is the phase error of the receiver channel; j is an imaginary unit; e.g. of the type-j·AIs a channel phase error compensation factor; VF (variable frequency)1Is a visibility function corrected by the phase error of the receiver channel;
for visibility function VF corrected by phase error of receiver channel1And performing near-field phase error correction to obtain a visibility function after the near-field phase error correction:
therein, VF2Is a visibility function corrected by near-field phase error; VF'0Target visibility function data of a point source at the center of a view field; angle (VF'0) Is VF'0The phase of (d);
wherein, the target visibility function data of the central point source of the field of view is a set of visibility function values corresponding to all baselines obtained by the two-unit scanning interferometer in the scanning process of observing a scene by the central point source of the field of view, namely V12(u, v) set; wherein, V12(u, v) the formula is:
wherein, TB(xi, eta) is the brightness temperature value of the point source target at the center of the view field; (xi, η) is the direction cosine coordinate:
wherein, θ and
the angle value of a point source target scene pixel point observed from the antenna array under the spherical coordinate system; (u, v) is a spatial frequency domain coordinate system in which the baseline is located;
the image inversion module is used for performing image inversion based on a Fourier transform relationship between the two-dimensional brightness temperature image of the near-field to-be-observed view field and the near-field error corrected visibility function by taking the two-dimensional brightness temperature image of the near-field to-be-observed view field as an input variable and adopting different fast inverse Fourier transform algorithms according to different antenna array configurations and obtaining the brightness temperature image of the near-field observation view field.
6. The self-calibration near-field imaging system based on the two-unit scanning interferometer of claim 5, wherein the visibility function obtaining module is configured to perform time-sharing sampling by using the two antenna units, perform complex correlation operation on sampling data received by the two receivers, obtain a visibility function value corresponding to each baseline, generate a visibility function value set, and obtain a visibility function; the specific process comprises the following steps:
carrying out complex correlation operation on sampling data received by two receivers in the two-unit scanning interferometer:
wherein, V12Performing complex correlation operation on the sampling data received by the two receivers at the time t to obtain a visibility function value corresponding to the baseline; e1(d1T) is sampled data received by one of the receivers; e2(d2T) is sampled data received by another receiver; d1The linear distance from a spatial domain sampling point to one antenna unit is obtained; d2The linear distance from a spatial domain sampling point to another antenna unit is obtained; wherein the sampling data is radiation field intensity;
the method comprises the steps of obtaining different baselines and corresponding visibility function values according to time-sharing sampling of two antenna units in a two-unit scanning interferometer, summarizing the visibility function values corresponding to each baseline, generating a visibility function value set, using the visibility function value set as a visibility function VF, and storing the visibility function value set.
7. The two-unit scanning interferometer-based self-calibration near-field imaging system of claim 5, wherein the antenna array is configured as a motion trajectory formed by movement of antenna units on corresponding carriages respectively placed on both horizontal and vertical directions; it includes: an open-loop two-dimensional antenna array and a closed-loop two-dimensional antenna array;
wherein the open loop two-dimensional antenna array comprises: the antenna comprises a Y-shaped two-dimensional antenna array, a U-shaped two-dimensional antenna array and a T-shaped two-dimensional antenna array;
the closed-loop two-dimensional antenna array comprises: a circular two-dimensional antenna array, a hexagonal two-dimensional antenna array, and a square two-dimensional antenna array.
8. The self-calibration near-field imaging system based on the two-unit scanning interferometer of claim 7, wherein image inversion is performed by adopting different fast inverse Fourier transform algorithms according to different antenna array configurations to obtain a bright temperature image of a near-field observation field of view; the method specifically comprises the following steps:
for the T-shaped two-dimensional antenna array, the square two-dimensional antenna array and the U-shaped two-dimensional antenna array, sampling points in a spatial frequency domain are distributed in a rectangular grid, and an IFFT algorithm is directly adopted to perform image inversion to obtain a brightness temperature image of a near-field observation field;
for the Y-shaped two-dimensional antenna array and the hexagonal two-dimensional antenna array, the sampling points of the spatial frequency domain are distributed in a hexagonal grid, and the image inversion is directly carried out by adopting a hexagonal IFFT algorithm to obtain a bright temperature image of a near-field observation field;
for the circular two-dimensional antenna array, the spatial frequency domain sampling points are distributed in a circular grid, and a pseudo-polar grid inverse Fourier algorithm is adopted to perform image inversion to obtain a bright temperature image of a near-field observation field.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1426130A (en) * | 2001-12-12 | 2003-06-25 | 中国科学院空间科学与应用研究中心 | Satellite carried rotary scanning interference type imaging microwave radiation meter |
| WO2009085294A1 (en) * | 2007-12-28 | 2009-07-09 | Interstitial, Llc | Synthetic aperture radar system |
| CN103323845A (en) * | 2013-05-13 | 2013-09-25 | 华中科技大学 | Image inversion method of non-uniform sampling comprehensive bore diameter radiometer |
| CN106019259A (en) * | 2016-07-11 | 2016-10-12 | 中国科学院上海技术物理研究所 | Laser frequency discriminating device and frequency discrimination method based on Mach-Zehnder interferometer |
| CN106556832A (en) * | 2016-11-01 | 2017-04-05 | 中国科学院国家空间科学中心 | A kind of distributed digital interference system based on synthetic aperture radiometer |
-
2020
- 2020-04-29 CN CN202010355679.1A patent/CN111505637B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1426130A (en) * | 2001-12-12 | 2003-06-25 | 中国科学院空间科学与应用研究中心 | Satellite carried rotary scanning interference type imaging microwave radiation meter |
| WO2009085294A1 (en) * | 2007-12-28 | 2009-07-09 | Interstitial, Llc | Synthetic aperture radar system |
| CN103323845A (en) * | 2013-05-13 | 2013-09-25 | 华中科技大学 | Image inversion method of non-uniform sampling comprehensive bore diameter radiometer |
| CN106019259A (en) * | 2016-07-11 | 2016-10-12 | 中国科学院上海技术物理研究所 | Laser frequency discriminating device and frequency discrimination method based on Mach-Zehnder interferometer |
| CN106556832A (en) * | 2016-11-01 | 2017-04-05 | 中国科学院国家空间科学中心 | A kind of distributed digital interference system based on synthetic aperture radiometer |
Non-Patent Citations (4)
| Title |
|---|
| "基于高速数字相关器的太赫兹干涉仪系统研究";韩东浩;《电子与信息学报》;20160430;第38卷(第4期);第6.1节 * |
| "干涉式成像微波辐射计遥感图像的模拟与成像分析";张成;《中国优秀博硕士学位论文全文数据库(博士)信息科技辑》;20081015;第3.2.1节，第3.4-3.4.1节，第6节 * |
| "旋转圆环阵列综合孔径微波辐射计系统研究";韩东浩;《中国优秀博硕士学位论文全文数据库(博士)信息科技辑》;20170930;第2.1.2.3节，第5.1.5节 * |
| "综合孔径微波辐射计近场成像方法";张成;《中国科学》;20111231;第41卷(第9期);第2.2节 * |
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