CN110490827B

CN110490827B - Rapid real-time processing method and system for airborne InSAR data

Info

Publication number: CN110490827B
Application number: CN201910811449.9A
Authority: CN
Inventors: 孙中昶; 李永杰; 韦立登; 郭华东
Original assignee: Sanya Zhongke Remote Sensing Research Institute; Institute of Remote Sensing and Digital Earth of CAS
Current assignee: Sanya Zhongke Remote Sensing Research Institute; Institute of Remote Sensing and Digital Earth of CAS
Priority date: 2019-08-30
Filing date: 2019-08-30
Publication date: 2022-04-12
Anticipated expiration: 2039-08-30
Also published as: CN110490827A

Abstract

The invention discloses a method and a system for rapidly processing airborne InSAR data in real time, which relate to the technical field of InSAR data processing and comprise the following steps: uploading coordinate information of ground control points in a test area before taking off; the carrier transmits electromagnetic waves and receives ground echo scattering data, airborne InSAR data information is generated according to the echo scattering data and is processed in real time, and then a DEM (digital elevation model) graph and a DOM (document object model) graph which accord with the national basic scale are transmitted to a ground station or a personal user in real time before the carrier lands. This application uploads ground control point information before taking off, through the aircraft transmission electromagnetic wave and receive ground echo scattering data after, can carry out quick, real-time, automatically data processing on the aircraft, before the aircraft lands or can pass DEM and the DOM that accord with the national standard scale after descending and give ground workstation or individual user, be favorable to improving the efficiency of data processing and transmission, better satisfying user's demand.

Description

Rapid real-time processing method and system for airborne InSAR data

Technical Field

The invention relates to the technical field of InSAR data processing, in particular to a method and a system for quickly processing airborne InSAR data in real time.

Background

The Digital Elevation Model (DEM) is a solid ground Model which describes the spatial distribution of the terrain form of an area, is a virtual representation of the terrain form and expresses the ground Elevation in the form of a group of ordered numerical arrays. The Digital ortho-image Map (DOM) is a Digital ortho-image data set generated by performing ortho-correction, edge-joining, color adjustment and mosaic on an aerospace image by using a DEM and cutting the aerospace image according to a certain range.

The Interferometric Synthetic Aperture Radar (Interferometric Radar) technology is from the United states, is continuously improved and mature in developed countries in Europe and America, and the application field of the Interferometric Synthetic Aperture Radar is continuously popularized. China develops an airborne high-resolution InSAR technology in recent years and researches the application of the technology in the aspect of topographic mapping.

As a new and advanced technical means, InSAR technology, in particular airborne high-resolution InSAR technology, is not widely applied to acquisition of DEM and DOM at present. In the prior art, the DEM and the DOM are usually obtained by an aerial photogrammetry method, the aerial photogrammetry method has the advantages of high efficiency, high precision, low labor intensity and the like, and is mainly carried out by a full-digital photogrammetry workstation, but when the aerial photogrammetry method is adopted for data acquisition, the influence of illumination and weather factors needs to be considered, the aerial photogrammetry method is limited by conditions such as cloud, fog, rain, dust, illumination and the like, and the aerial photogrammetry method is controlled by aviation, so that the expenditure and the cost are high; when the DEM is acquired by adopting an aerial photogrammetry method, the problem of abnormal elevation occurs in different images in the same flight band or adjacent image connecting edges between different flight bands, so that the overall consistency and continuity of the acquired DEM are influenced. Aiming at the problems existing when the DEM is obtained by the existing aerial photogrammetry method, a quick real-time processing method and a quick real-time processing system for airborne InSAR data which can be used for topographic mapping are urgently needed to be researched.

Disclosure of Invention

In view of the above, the present invention provides a method and a system for fast and real-time processing of airborne InSAR data, wherein ground control point information is uploaded before takeoff, after an electromagnetic wave is transmitted by a carrier and ground echo scattering data is received, fast, real-time and automatic data processing can be performed on the carrier, and the processed DEM and DOM meeting the national standard scale can be transmitted to a ground workstation or a personal user before or after landing of an airplane, which is beneficial to improving the efficiency of data processing and transmission and better meets the user requirements.

In order to solve the technical problem, the following technical scheme is adopted:

on one hand, the application provides a method for rapidly processing airborne InSAR data in real time, which is characterized by comprising the following steps:

uploading coordinate information of ground control points in a test area before taking off; the measuring area comprises at least one scene image;

the method comprises the steps that an airborne machine transmits electromagnetic waves and receives ground echo scattering data, airborne InSAR data information is generated according to the echo scattering data, the airborne InSAR data information comprises data information of a main image and data information of an auxiliary image, the data information of the main image and the auxiliary image at least comprises SLC data, IMG data and POS data of each scene image, and meanwhile the main image and the auxiliary image are rapidly processed in real time, specifically:

registering the SLC data of the primary image and the secondary image according to the IMG data; generating an interference graph and a coherence graph according to the registered main image SLC data and auxiliary image SLC data; filtering the interference pattern, and performing phase unwrapping on the interference pattern subjected to filtering processing to obtain an unwrapped phase pattern;

calculating to obtain interference parameters of each scene image according to the POS data, calibrating the interference parameters of the images through interference calibration or block adjustment, and calculating to obtain corrected interference parameters of each scene image;

acquiring elevation information of each image point on the image through phase-height conversion by using the POS data and the corrected interference parameters; obtaining the coordinates of each image point on a Gaussian plane by using a geometric relation according to the POS data and the corrected interference parameters; forming geographic coordinates by the elevation information of each image point and the coordinates of each image point on a Gaussian plane, performing resampling according to the geographic coordinates, assigning the elevation information and the gray value of the image to the resampled image points, and generating a DEM (digital elevation model) and a DOM (document object model);

splicing and embedding all adjacent DEMs in the measuring area to form a DEM block diagram; splicing and embedding all adjacent DOM in the measuring area to form a DOM module diagram;

performing standard framing on the DEM module diagram and the DOM module diagram to generate a DEM diagram and a DOM diagram which accord with the national basic scale;

and transmitting the DEM graph and the DOM graph which conform to the basic national scale to a ground station or an individual user in real time before the carrier lands.

Optionally, wherein:

the registering of the SLC data of the primary image and the secondary image according to the IMG data specifically includes: calculating the relative offset of the matching position between the SLC complex data of the main image and the auxiliary image, calculating the coordinate conversion relation between the SLC complex data of the main image and the auxiliary image according to the relative offset of the matching position, and resampling the SLC data of the auxiliary image.

Optionally, wherein:

the filtering processing of the interference pattern specifically includes: the method adopts a complex interference pattern self-adaptive filtering method combining median filtering and power spectrum weighting.

Optionally, wherein:

the phase unwrapping is performed on the filtered interferogram, and specifically includes:

and performing real phase unwrapping on the interferogram by using a high-performance GPU parallel processing method based on a minimum balanced tree/forest method to obtain the unwrapped phase of the interferogram.

Optionally, wherein:

the interference parameters of the images are calibrated through interference calibration, and the corrected interference parameters of the images of each scene are obtained through calculation, which specifically comprises the following steps: extracting pixel coordinates and unwrapping phases of the ground control points in the measuring area on the image according to the coordinate information of the ground control points to generate an image control point file; inputting the image control point file and the POS data, and calibrating by adopting a method based on a sensitivity equation, wherein the sensitivity equation is expressed as: Δ ═ F × Δ x + M, where Δ is an elevation deviation value of a ground control point, F is a sensitivity matrix, Δ x is an interference parameter deviation to be estimated, and M is noise;

correcting the interference parameters to be calibrated according to the interference parameter deviation to be estimated to obtain corrected interference parameters of each scene image; wherein the interference parameters at least include phase offset, baseline length, baseline tilt angle and time delay.

Optionally, wherein:

the calibration of the interference parameters of the images through the adjustment of the area network, and the calculation of the corrected interference parameters of the images of each scene are specifically as follows: and automatically selecting a connecting point in the overlapping area of each scene image, and obtaining corrected interference parameters and three-dimensional coordinates of the connecting point through adjustment calculation according to the initial coordinate information of the ground control point and the connecting point.

On the other hand, the application provides a quick real-time processing system of airborne InSAR data, its characterized in that includes: the system comprises a control point uploading module, an antenna, a data information generating module, a data information processing module and an image transmission module;

the control point uploading module is used for uploading coordinate information of the ground control point in the test area before takeoff; the measuring area comprises at least one scene image;

the antenna is used for transmitting electromagnetic waves and receiving ground echo scattering data;

the data information generating module is used for generating airborne InSAR data information according to the echo scattering data, the airborne InSAR data information comprises data information of a main image and data information of an auxiliary image, and the data information of the main image and the auxiliary image comprises SLC data, IMG data and POS data of each scene image; the POS terminal is also used for calculating interference parameters of each scene image according to the POS data;

the data information processing module is used for rapidly processing the main image and the auxiliary image in real time and comprises an interference processing module, an interference calibration module, a regional net adjustment module, a geocoding module, a splicing mosaic module and a standard framing module;

the interference processing module is used for registering SLC data of the main image and the auxiliary image according to IMG data; the interference image and the coherence image are generated according to the registered main image SLC data and auxiliary image SLC data; the phase unwrapping module is also used for carrying out filtering processing on the interference pattern and carrying out phase unwrapping on the interference pattern after filtering processing to obtain an unwrapped phase pattern;

the interference calibration module or the block adjustment module is used for calibrating the interference parameters of the images and calculating to obtain the corrected interference parameters of each scene image;

the geocoding module is used for obtaining elevation information of each image point on the image through phase-height conversion by utilizing the POS data and the corrected interference parameters; the POS machine is also used for obtaining the coordinates of each image point on a Gaussian plane by using a geometric relation according to the POS data and the corrected interference parameters; the image processing device is also used for forming geographic coordinates by the elevation information of each image point and the coordinates of each image point on the Gaussian plane, resampling is carried out according to the geographic coordinates, the elevation information and the gray value of the image are assigned to the resampled image points, and a DEM (digital elevation model) and a DOM (document object model) are generated;

the splicing and embedding module is used for splicing and embedding all adjacent DEMs in the measuring area to form a DEM module diagram; the DOM module graph is formed by splicing and embedding all adjacent DOM in the measuring area;

the standard framing module is used for performing standard framing on the DEM module diagram and the DOM module diagram to generate a DEM diagram and a DOM diagram which accord with a national basic scale;

and the image transmission module is used for transmitting the DEM and DOM images which accord with the national basic scale to a ground station or an individual user in real time before the carrier lands.

Optionally, wherein:

the interference calibration module is used for extracting pixel coordinates and unwrapping phases of the ground control points in the measurement area on the image according to the coordinate information of the ground control points to generate an image control point file; and the POS terminal is also used for inputting the image control point file and the POS data, and calibrating by adopting a method based on a sensitivity equation, wherein the sensitivity equation is expressed as: Δ ═ F × Δ x + M, where Δ is an elevation deviation value of a ground control point, F is a sensitivity matrix, Δ x is an interference parameter deviation to be estimated, and M is noise;

the interference parameter correction module is also used for correcting the interference parameters to be calibrated according to the interference parameter deviation to be estimated to obtain the corrected interference parameters of each scene image; wherein the interference parameters at least include phase offset, baseline length, baseline tilt angle and time delay.

Optionally, wherein:

and the area network adjustment module is used for automatically selecting connection points in the overlapped area of each scene image, and obtaining corrected interference parameters and three-dimensional coordinates of the connection points through adjustment calculation according to the initial coordinate information of the ground control points and the connection points.

Compared with the prior art, the method and the system for rapidly processing the airborne InSAR data in real time at least realize the following beneficial effects:

(1) according to the rapid real-time processing method and system for airborne InSAR data, the ground control point information is uploaded before takeoff, after the electromagnetic waves are transmitted by the aircraft and the ground echo scattering data are received, rapid, real-time and automatic data processing can be carried out on the aircraft based on the GPU parallel processing technology, processed DEMs and DOMs which accord with the national standard scale can be transmitted to a ground workstation or a personal user before or after the aircraft lands, the efficiency of data processing and transmission is improved, and the user requirements are better met.

(2) According to the method and the system for rapidly processing the airborne InSAR data in real time, the airborne electromagnetic waves are transmitted by the airborne device and the ground echo scattering data are received, the influence of weather and illumination is avoided, the ground echo data can be acquired all the day and all the weather, and accordingly the DEM and the DOM are extracted more flexibly.

(3) According to the method and the system for rapidly processing the airborne InSAR data in real time, when DEM and DOM are generated, the main image and the auxiliary image are registered to generate the interferogram and the coherence map, the interferogram is filtered and then phase unwrapped, and therefore the influence of phase noise in the interferogram on the accuracy and the computational efficiency of phase unwrapping and the subsequent interference measurement accuracy can be avoided; the interference parameters are calibrated by the block adjustment method, the interference parameter deviation of the images can be strictly corrected, and the interference parameters after the images of all scenes are corrected are obtained, so that the accuracy of DEM and DOM generation can be improved, the constraint relation between the images is established by the block adjustment method, the inversion height difference at the joint can be reduced, and the integral consistency and continuity of the DEM and the DOM can be enhanced.

Of course, it is not necessary for any product in which the present invention is practiced to achieve all of the above-described technical effects simultaneously.

Other features of the present invention and advantages thereof will become apparent from the following detailed description of exemplary embodiments thereof, which proceeds with reference to the accompanying drawings.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention.

Fig. 1 is a flowchart illustrating an onboard InSAR data real-time processing method according to an embodiment of the present application;

FIG. 2 is a flow chart illustrating fast real-time processing of a primary image and a secondary image according to an embodiment of the present application;

FIG. 3 is a flow chart of splicing to form a DEM block diagram according to an embodiment of the present disclosure;

FIG. 4 is a flowchart illustrating a process of tessellating a DOM block diagram according to an embodiment of the present application;

fig. 5 is a flowchart illustrating registration of a primary image and a secondary image according to an embodiment of the present application;

FIG. 6 is a flow chart of an interferogram filtering process provided by an embodiment of the present application;

FIG. 7 is a flow chart of a method for balancing trees/forests based on minimum measure provided by an embodiment of the present application;

FIG. 8 is a flow chart of interferometric scaling provided by embodiments of the present application;

FIG. 9 is a flow chart of block adjustment provided by an embodiment of the present application;

fig. 10 is a schematic structural diagram of a fast real-time processing system for airborne InSAR data according to an embodiment of the present application;

fig. 11 is a schematic structural diagram of a data information processing module according to an embodiment of the present application.

Detailed Description

Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that: the relative arrangement of the components and steps, the numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise.

The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate.

In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.

As a new and advanced technical means, InSAR technology, in particular high-resolution airborne InSAR technology, is not widely applied to acquisition of DEM and DOM at present. In the prior art, the DEM and the DOM are usually obtained by an aerial photogrammetry method, the aerial photogrammetry method has the advantages of high efficiency, high precision, low labor intensity and the like, and is mainly carried out by a full-digital photogrammetry workstation, but when the aerial photogrammetry method is adopted for data acquisition, the influence of illumination and weather factors needs to be considered, the aerial photogrammetry method is limited by conditions such as cloud, fog, rain, dust, illumination and the like, and the aerial photogrammetry method is controlled by aviation, and the expenditure is high; when the DEM is acquired by adopting an aerial photogrammetry method, the problem of abnormal elevation occurs in different images in the same flight band or adjacent image connecting edges between different flight bands, so that the overall consistency and continuity of the acquired DEM are influenced. Aiming at the problems existing when the DEM is obtained by the existing aerial photogrammetry method, a quick real-time processing method and a quick real-time processing system for airborne InSAR data which can be used for topographic mapping are urgently needed to be researched.

The following detailed description is to be read in connection with the drawings and the detailed description.

Fig. 1 is a flowchart of a method for processing airborne InSAR data in real time according to an embodiment of the present application, and fig. 2 is a flowchart of a method for processing primary and secondary images in real time according to an embodiment of the present application, please refer to fig. 1-2, where the method for processing airborne InSAR data in real time according to an embodiment of the present application includes:

step 10: uploading coordinate information of ground control points in a test area before taking off; the measuring area comprises at least one scene image;

step 20: the method comprises the steps that an airborne machine transmits electromagnetic waves and receives ground echo scattering data, airborne InSAR data information is generated according to the echo scattering data, the airborne InSAR data information comprises data information of a main image and data information of an auxiliary image, the data information of the main image and the auxiliary image at least comprises SLC data, IMG data and POS data of each scene image, and meanwhile the main image and the auxiliary image are rapidly processed in real time, and the method specifically comprises the following steps:

step 21: registering the SLC data of the main image and the auxiliary image according to the IMG data; generating an interference graph and a coherence graph according to the registered main image SLC data and auxiliary image SLC data; filtering the interference pattern, and performing phase unwrapping on the interference pattern subjected to filtering processing to obtain an unwrapped phase pattern;

step 22: calculating to obtain interference parameters of each scene image according to POS data, calibrating the interference parameters of the images through interference calibration or block adjustment, and calculating to obtain corrected interference parameters of each scene image;

step 23: obtaining elevation information of each image point on the image through phase-height conversion by using POS data and the corrected interference parameters; obtaining the coordinates of each image point on a Gaussian plane by using a geometric relation according to the POS data and the corrected interference parameters; forming geographic coordinates by the elevation information of each image point and the coordinates of each image point on the Gaussian plane, performing resampling according to the geographic coordinates, assigning the elevation information and the gray value of the image to the resampled image points, and generating a DEM (digital elevation model) and a DOM (document object model);

step 24: splicing and embedding all adjacent DEMs in the measuring area to form a DEM block diagram; splicing and embedding all adjacent DOM in the measuring area to form a DOM module diagram; (ii) a

Step 25: performing standard framing on the DEM module diagram and the DOM module diagram to generate a DEM diagram and a DOM diagram which accord with the national basic scale;

step 30: and transmitting the DEM graph and the DOM graph which conform to the basic national scale to a ground station or an individual user in real time before the carrier lands.

Specifically, according to the method for processing the onboard InSAR data in real time provided by the embodiment of the application, coordinate information of ground control points in a detection area is uploaded before an aircraft takes off through the step 10, the selected detection area at least comprises a scene image, and the control points are manually arranged, so that flat ground is convenient, transportation and measurement are easy, the flat ground is more stable, and three-dimensional coordinates are not easy to change, therefore, when the control points are arranged, the control points are preferably arranged on the flat ground, and in addition, in order to ensure the correctness of interference phases of the control points and the radar can observe the control points, the control points need to be arranged at positions far away from shadows and overlapping masks; in step 20, the vehicle transmits electromagnetic waves through the antennas and receives echo scattering data, and generates airborne InSAR data from the received echo scattering data, where the airborne InSAR data includes main image data information and auxiliary image data information, where the main image and the auxiliary image are two Complex images with coherence generated from the echo scattering data received by the two antennas on the vehicle, and because the distance between the two antennas on the vehicle is very close, the main image and the auxiliary image are imaged at substantially the same time, the main image and the auxiliary image data information at least include Single viewing Complex (SLC) data, IMG data, and Position and Orientation System (POS) data of each scene, and parameter information such as a baseline, an absolute time delay, and a Position and attitude of the vehicle platform can be directly obtained through the POS data.

For an InSAR data processing system, accurate terrain elevation measurement needs to be guaranteed by an accurate interference phase, so that sub-pixel-level accurate registration needs to be carried out on an interference complex image, image registration is carried out on a main image and an auxiliary image according to IMG data through step 21, an interferogram and a coherent image are generated according to SLC data of a main image and an auxiliary image after registration, filtering processing is carried out on the interferogram, then phase unwrapping is carried out on the filtered interferogram, phase noise exists in the interferogram due to factors such as thermal noise, time, geometric decorrelation, Doppler centroid decorrelation and the like of the system, and therefore the interferogram needs to be filtered before phase unwrapping is carried out, and therefore the influence of the phase noise on the accuracy, the calculation efficiency and the subsequent interference measurement accuracy are avoided; in step 22, the interference parameters of each scene image can be calculated through the POS data, the interference parameters include parameter information such as the altitude, the baseline tilt angle, the baseline length, and the close distance of each image point, and then the interference parameters of the images are calibrated by an interference calibration or a local area network adjustment method.

After the corrected interference parameters are obtained, the elevation information of each image point needs to be obtained, and in step 23, according to the unwrapping phase obtained in step 21 and the parameters of the flight height, the baseline inclination angle, the baseline length, the near distance and the like obtained in step 22, the elevation information of each image point on the image can be obtained through phase-height conversion: H-H-R₁cosθ，

Wherein H represents elevation information, H represents altitude, and R represents altitude₁Representing pitch, pitch R₁The distance from the antenna to the ground image point can be obtained according to the close distance, theta represents the side viewing angle, alpha represents the base line inclination angle, lambda represents the wavelength,

the absolute phase is shown, which can be obtained from the unwrapped phase, B is the base length, the side view angle theta of a certain image point can be obtained by knowing the base line inclination angle and the phase difference of the point, and the position (X) of the airplane on each scanning line in the azimuth direction is obtained from the POS data_s，Y_s，Z_s) The Gaussian plane coordinates (x) of the line are obtained by coordinate conversion_s，y_s) Then, the coordinate (x) of the image point on the Gaussian plane is obtained by using the geometrical relation_p，y_p) Is composed of

Wherein beta is the squint angle, f_DAnd forming geographic coordinates according to the elevation information of each image point and the coordinates of each image point on the Gaussian plane, performing resampling according to the geographic coordinates, assigning the elevation information and the gray value of the image to the resampled image points, and generating the DEM and the DOM meeting the precision requirement.

Fig. 3 is a flowchart illustrating splicing to form a DEM block diagram according to an embodiment of the present application, and fig. 4 is a flowchart illustrating inlaying to form a DOM block diagram according to an embodiment of the present application, please refer to fig. 3-4, after generating a DOM and a DEM, in step 24, all adjacent DEMs in the measurement area are spliced and inlaid to form a DEM block diagram; splicing and embedding all adjacent DOM in the measuring area to form a DOM module diagram; it should be noted that when the DEM and the DOM are spliced and embedded to form the module diagram, the image hues at two sides of the embedding line need to be adjusted at the same time, so that there is no obvious splicing or embedding trace between two adjacent images. And 25, standard framing is carried out on the DEM module diagram and the DOM module diagram, namely the DEM module diagram and the DOM module diagram are cut according to a preset scale, the width and the length of the breadth, the coordinates of the corner points in the southwest and the latitude and longitude intervals to form the DEM diagram and the DOM diagram which accord with the national basic scale, and the cutting can be carried out according to the national basic topographic map when the DEM module diagram and the DOM module diagram are subjected to standard framing. The DEM and DOM maps are then transmitted in real time to a ground station or individual user in compliance with the national base scale, via step 30, before the carrier lands.

According to the rapid real-time processing method of the airborne InSAR data, provided by the embodiment of the application, after the ground echo scattering data is received by the aircraft, the rapid, real-time and automatic data processing can be carried out on the aircraft, and the processed DEM and DOM which meet the national standard scale can be transmitted to a ground workstation or a personal user before or after the aircraft lands, so that the efficiency of data processing and transmission can be improved, and the user requirements can be better met; in the data processing process, after the interferogram is generated, the interferogram is filtered and then subjected to phase unwrapping, so that the influence of phase noise in the interferogram on the phase unwrapping precision, the calculation efficiency and the subsequent interferometric measurement precision can be avoided; the interference parameters are calibrated by a block adjustment method, the interference parameter deviation of the images can be strictly corrected, and the corrected interference parameters of the images of all scenes are obtained, so that the DEM and DOM generation precision can be improved, the constraint relation between the images is established by the block adjustment method, the inversion height difference at the joint can be reduced, and the overall consistency and continuity of the DEM and the DOM are enhanced; in addition, this application is through the transmission of loader antenna and receiving ground echo scattering data, does not receive weather influence, can realize all-weather, carry out ground echo data acquisition all day time, all weather to make DEM and DOM draw more nimble.

Optionally, fig. 5 is a flowchart illustrating a registration process of a primary image and a secondary image according to an embodiment of the present application, please refer to fig. 5, in step 21, the registering is performed on SLC data of the primary image and the secondary image according to the IMG data, specifically: calculating the relative offset of the matching position between the SLC complex data of the main image and the auxiliary image, calculating the coordinate conversion relation between the SLC complex data of the main image and the auxiliary image according to the relative offset of the matching position, and resampling the SLC data of the auxiliary image. Specifically, the key of the registration of the SLC data of the InSAR complex image is to determine the relative offset of the matching position between the SLC complex data of the two images, in this embodiment, a complex correlation fine registration method is adopted, and the maximum correlation coefficient is obtained based on the correlation coefficient interpolation of a plurality of pixels around an image point, so that a more accurate matching position and relative offset are determined, then the coordinate conversion relationship between the SLC complex data of the main image and the auxiliary image is calculated according to the relative offset of the matching position, and the SLC data of the auxiliary image is resampled.

When calculating the relative offset of the matching position, uniformly selecting a plurality of pixel points on the main image, determining a matching window of M by taking a certain pixel point as the center in the main image, determining a search window of N by taking the point corresponding to the pixel point in the auxiliary image as the center due to the smaller offset of the main image and the auxiliary image, determining a corresponding window of M by M in the search window, and according to a formula

Calculating a correlation coefficient gamma between the corresponding window and the matching window, wherein u₁(n, m) and u₂(n, m) represent two complex data at corresponding positions (n, m) in the matching window and the corresponding window, respectively, u₂ ^*(n, m) represents u₂The conjugate complex number of (n, m), the function of denominator in the above formula is mainly normalized, and the determination of the correlation coefficient mainly depends on numerator, so that the formula for calculating the correlation coefficient y by the above formula can be rewritten as

Then Fast computation is performed using Fast Fourier Transform (FFT) of convolutionObtaining γ ═ FFT^-1(FFT^*(u₁)FFT(u₂) Thus, the local image is converted into a frequency domain by adopting FFT, inverse transformation is carried out after conjugate multiplication to obtain a correlation function of the whole image, each correlation coefficient value in the matching window and the corresponding window is calculated and stored according to row and column searching, the position of the maximum value of the correlation coefficient after modulus taking is the matching position, the relative offset between the matching positions in the matching window and the corresponding window is recorded, the maximum correlation coefficient of other pixel points in the main image and the relative offset of the matching positions are sequentially calculated, and then the matching positions are taken as the center, and the correlation coefficient is interpolated by a binary three-point interpolation method at the interval of 0.01 pixel to sequentially determine the precise matching position and the precise relative offset of each pixel point. After obtaining the relative offset of each pixel point, deleting the pixel point with the correlation coefficient less than 0.9, and performing second-order polynomial fitting on the pixel point with the correlation coefficient greater than 0.9 by adopting a least square method to determine the relative offset of any matching position in the two images, thereby calculating the coordinate conversion relation of the complex image pair as follows:

wherein, the coefficient of the polynomial is the fitting parameter, (x, y) is the pixel coordinate in the main image, and (u, v) is the relative coordinate offset of the corresponding matching position of the main and auxiliary images.

It should be noted that the coordinates of the matching position in the auxiliary image obtained after registration are not an integer, and therefore interpolation calculation needs to be performed according to the numerical values of the adjacent number points, such as the real part numerical value and the imaginary part numerical value, that is, resampling is performed on the SLC data of the auxiliary image. In addition, the above-mentioned binary three-point interpolation method and the least square method for calculating the relative offset can be referred to the algorithm in the prior art, and are not specifically described here.

Optionally, fig. 6 is a flowchart illustrating a filtering processing flow of an interferogram according to an embodiment of the present application, please refer to fig. 6, where in step 21, the filtering processing is performed on the interferogram, specifically: the method adopts a complex interference pattern self-adaptive filtering method combining median filtering and power spectrum weighting. Specifically, in this embodiment, an adaptive filtering method combining median filtering and power spectrum weighting is used to perform filtering processing on an interferogram, divide a real part and an imaginary part into 5 × 5 windows, perform two-dimensional FFT, perform weighting processing after obtaining a power spectrum, perform Inverse Fast Fourier Transform (IFFT), and convert the power spectrum into a time domain, so as to obtain an interferogram filtering result. It should be noted that the complex interferogram adaptive filtering method combining the median filtering and the power spectrum weighting is only one filtering method in this embodiment of the present application, and other filtering methods may also be adopted in other embodiments, which is not specifically limited in this application.

Optionally, referring to fig. 7, fig. 7 is a flowchart of a minimum balanced tree/forest method according to an embodiment of the present application, where in the step 21, the phase unwrapping is performed on the filtered interferogram, specifically: and (3) carrying out real phase expansion on the interference pattern by utilizing a high-performance GPU parallel processing method based on a minimum balanced tree/forest method to obtain the phase after the interference pattern is unwrapped. Specifically, there are various methods for phase unwrapping, in this embodiment, a method based on a minimum balanced tree/forest is used for phase unwrapping, and positive and negative residual point sources in an image are detected according to a quality weight factor Q of a given area, where the polarity of the positive residual point source is +1 and the polarity of the auxiliary residual point source is-1. At (x, y), the reliability index of the positive residual point is defined as P⁺The reliability index of the negative residual point is P^-Respectively defined as: p⁺＝min{P_S(x,y)|S∈R⁺}，P^-＝min{P_S(x,y)|S∈R^-In which R is⁺And R^-Positive and negative residual error point sets; defining the dual reliability index as P, P (x, y) being P⁺(x,y)+P^-(x, y). Forming a phase continuity reliability map according to the phase continuity reliability index, and determining a minimum reliable residual point pair for a positive residual point S_aAnd negative residual point S_bIn other words, if the phase continuity reliability index is obtainedAre called the least reliable residual point pair, and define the connecting line

And according to the minimum reliable residual error point pair, carrying out discontinuous boundary tracking and constructing a minimum balanced tree/forest. Meanwhile, according to the phase continuity reliability map, the most reliable phase point is detected, and the most reliable path l from the reference point to the target point is expressed as

Based on this equation, at (x, y), the most reliable integration path is taken as its priority F, and the unwrapping order is determined based on the priority F, where F (x, y) is min { P (x, y) | (x, y) ∈ l }.

In other embodiments, the phase unwrapping may be performed by using a minimum cost stream method, in which a residual value is first calculated by an interference phase matrix in an interference pattern, and then calculated by a minimum cost stream algorithm

According to

Deducing k₁(i, j) and k₂(i, j) when

When the temperature of the water is higher than the set temperature,

when in use

When the temperature of the water is higher than the set temperature,

k can be obtained by the same method₂(i, j) by using k₁(i, j) and k₂(i, j) calculating the phase gradient Δ₁Phi (i, j) and delta₂Phi (i, j) is followed by

Calculating the real phase phi (i, j) of the interference pattern; or other methods such as a least square method, a residual/branch-cut method, a kalman filtering method, and the like may also be used to obtain the true phase of the interferogram, which is not specifically limited in this application.

Optionally, fig. 8 is a flowchart of interference calibration provided in the embodiment of the present application, please refer to fig. 8, in step 22, the interference parameters of the images are calibrated through the interference calibration, and the corrected interference parameters of each scene image are obtained through calculation, specifically: extracting pixel coordinates and unwrapping phases of ground control points in a measuring area on an image according to coordinate information of the ground control points to generate an image control point file; inputting an image control point file and POS data, and calibrating by adopting a method based on a sensitivity equation, wherein the sensitivity equation is expressed as: Δ ═ F × Δ x + M, where Δ is an elevation deviation value of a ground control point, F is a sensitivity matrix, Δ x is an interference parameter deviation to be estimated, and M is noise; correcting the interference parameters to be calibrated according to the deviation of the interference parameters to be estimated to obtain the corrected interference parameters of each scene image; wherein the interference parameters at least include phase offset, baseline length, baseline tilt angle and time delay.

Specifically, referring to fig. 8, when calculating the interference parameters after correcting each scene image, an interference parameter calibration method based on a sensitivity equation may be used to calculate, and a basic target positioning equation is differentiated by different interference parameters to form an interference parameter sensitivity equation, a relationship between a target function and interference parameter deviations is established, that is, each differential equation indicates the influence sensitivity of the interference parameter on a target positioning error, so interference calibration may be performed based on a sensitivity equation Δ ═ F Δ x + M, where Δ is an elevation deviation value of a ground control point, F is a sensitivity matrix, Δ x is an interference parameter deviation to be estimated, and M is noise, reasonable ground control points are distributed through a plurality of positions to form a sensitivity equation set, an estimation value of each interference parameter deviation is calculated by solving the equation set, and then the interference parameters are corrected by using the estimation value of the interference parameter deviation, and the corrected interference parameters are applied to carry out target three-dimensional reconstruction, so that the DEM precision is improved. It should be noted that, when the interference parameter correction is performed, iterative computation needs to be performed for multiple times, and after the interference parameter is corrected by using the estimated value of the interference parameter deviation each time, the DEM needs to be recalculated according to the corrected interference parameter, and it is determined whether the mean square deviation of the ground elevation calculated in the previous and subsequent times reaches the ideal precision, and after the mean square deviation of the ground elevation calculated in the previous and subsequent times reaches the ideal precision, the iteration is stopped, and the latest corrected interference parameter is used as the final corrected interference parameter.

Optionally, fig. 9 is a flowchart of the adjustment of the local area network provided in the embodiment of the present application, please refer to fig. 9, in step 22, the interference parameters of the images are calibrated through the adjustment of the local area network, and the corrected interference parameters of each scene image are calculated, which specifically includes: and automatically selecting a connecting point in the overlapping area of each scene image, and obtaining the corrected interference parameter and the three-dimensional coordinate of the connecting point through adjustment calculation according to the initial coordinate information of the ground control point and the connecting point.

Specifically, referring to fig. 9, when calculating the corrected interference parameters of each scene image, a block adjustment method may be used for calculation, first, selecting connection points in the overlap area of each scene image, where the selected connection points should be uniformly distributed, and the number of the connection points and the number of the control points need to meet the block adjustment requirement, and the selected connection points may be selected in the space band or between the space bands, where the overlap degree of each scene image in the space band is about 10%, and when selecting the connection points in the space band, a row of connection points is uniformly selected in the middle of the overlap portion of each image in the space band; the overlap degree between the flight belts is about 30%, and when the connection points are selected between the flight belts, two rows of connection points are uniformly selected near the overlapped parts of the adjacent flight belts.

After the connection points are selected, according to initial coordinate information of a small number of control points and the connection points, elevation area network pre-adjustment and plane area network pre-adjustment are carried out, and two types of unknowns are alternately approximated and calculated according to correction values of external orientation elements in each image elevation and correction values of coordinates of the connection points. When elevation area network adjustment is carried out, substituting the initial value of the external orientation element in elevation of each scene image and the initial value of the elevation coordinate of the connecting point into an elevation error calculation formula to obtain a correction value of the external orientation element in elevation of each scene image, adding the initial value and the correction value to obtain the external orientation element in elevation of each scene image, calculating the elevation coordinate of the connecting point according to the external orientation element in elevation of each scene image, carrying out repeated iterative calculation until the difference value of the elevation coordinates of the front and back times is smaller than a set threshold value, setting iteration times, the threshold value and baseline inclination angle fitting times before adjustment calculation, inputting 0, indicating baseline inclination angle constant item correction, 1 indicating baseline inclination angle one-time correction, 2 indicating baseline inclination angle two-time correction, and 3 indicating baseline inclination angle three-time correction. After the leveling of the elevation area network is completed, performing plane area network leveling, wherein the step of plane area network leveling is the same as the step of elevation area network leveling, and is not repeated here, and similarly, before performing plane area network leveling, iteration times, a threshold value, yaw angle fitting times and pitch angle fitting times also need to be set; when the number of times of the yaw angle fitting is set, inputting 0 to represent the correction of a yaw angle constant term, 1 to represent the correction of a yaw angle primary term, 2 to represent the correction of a yaw angle secondary term, and 3 to represent the correction of a yaw angle tertiary term; when the fitting times of the pitch angle are set, 0 is input to indicate the correction of a pitch angle constant term, 1 indicates the correction of a pitch angle primary term, 2 indicates the correction of a pitch angle secondary term, and 3 indicates the correction of a pitch angle tertiary term. It should be noted that, when performing elevation block adjustment and plane block adjustment, after obtaining coordinate information of an exterior orientation element and a connection point of each scene image through pre-adjustment calculation, where the exterior orientation element of each scene image includes an elevation coordinate and a plane coordinate of each scene image, it is necessary to perform coarse adjustment detection on the connection point and the control point, eliminate or correct coarse adjustment points in the connection point and the control point, and when performing coarse adjustment elimination on the control point and the connection point, it is necessary to set a threshold of the control point and the connection point.

Based on the same inventive concept, the present application further provides a fast real-time processing system for airborne InSAR data, fig. 10 is a schematic structural diagram of the fast real-time processing system for airborne InSAR data provided in the present application embodiment, fig. 11 is a schematic structural diagram of a data information processing module 140 provided in the present application embodiment, please refer to fig. 10-11, and the fast real-time processing system 100 for airborne InSAR data provided in the present application embodiment includes: a control point uploading module 110, an antenna 120, a data information generating module 130, a data information processing module 140 and an image transmission module 150;

the control point uploading module 110 is used for uploading coordinate information of ground control points in the test area before takeoff; the measuring area comprises at least one scene image;

an antenna 120 for transmitting electromagnetic waves and receiving ground echo scattering data;

the data information generating module 130 is configured to generate airborne InSAR data information according to the echo scattering data, where the airborne InSAR data information includes data information of a main image and data information of an auxiliary image, and the data information of the main image and the auxiliary image includes SLC data, IMG data, and POS data of each scene image; the system is also used for calculating interference parameters of each scene image through POS data;

the data information processing module 140 is used for performing fast real-time processing on the main image and the auxiliary image, and comprises an interference processing module 141, an interference scaling module 142, a block adjustment module 146, a geocoding module 143, a mosaic splicing module 144 and a standard framing module 145;

an interference processing module 141, configured to perform registration on SLC data of the primary image and the secondary image according to the IMG data; the interference image and the coherence image are generated according to the registered main image SLC data and auxiliary image SLC data; the phase unwrapping module is also used for carrying out filtering processing on the interference pattern and carrying out phase unwrapping on the interference pattern after the filtering processing to obtain an unwrapped phase pattern;

the interference calibration module 142 or the block adjustment module 146 is configured to calibrate interference parameters of the images, and calculate to obtain corrected interference parameters of each scene image;

the geocoding module 143 is configured to obtain elevation information of each image point on the image through phase-height conversion by using the POS data and the corrected interference parameters; the system is also used for acquiring the coordinates of each image point on the Gaussian plane by using the geometric relation according to the POS data and the corrected interference parameters; the image processing device is also used for forming geographic coordinates by the elevation information of each image point and the coordinates of each image point on the Gaussian plane, resampling is carried out according to the geographic coordinates, the sum of the elevation information of the image and the gray value is given to the resampled image points, and a DEM (digital elevation model) and a DOM (document object model) are generated;

the splicing and embedding module 144 is used for splicing and embedding all adjacent DEMs in the measuring area to form a DEM module diagram; the DOM module graph is formed by embedding and inlaying all adjacent DOM in the measuring area;

the standard framing module 145 is used for performing standard framing on the DEM module diagram and the DOM module diagram to generate the DEM diagram and the DOM diagram which conform to the national basic scale;

and the image transmission module 150 is used for transmitting the DEM and DOM images which accord with the national basic scale to a ground station or an individual user in real time before the carrier lands.

Specifically, the system 100 for processing airborne InSAR data in real time provided in the embodiment of the present application includes: a control point uploading module 110, an antenna 120, a data information generating module 130, a data information processing module 140 and an image transmission module 150; before the aircraft takes off, the control point uploading module 110 uploads the coordinate information of the ground control point in the measurement area, in general, the selected measurement area at least comprises a scene image, and the control points are artificially arranged, so that the ground is convenient, the transportation and the measurement are easy, the ground is more stable, and the three-dimensional coordinate is not easy to change, therefore, when the control points are arranged, the control points are preferably arranged on the ground, and in addition, in order to ensure the correctness of the interference phase of the control points and the radar can observe the control points, the control points are required to be arranged at positions far away from the shadow and the overlapping mask; after the aerial carrier transmits electromagnetic waves through the antenna 120 and receives echo scattering data, the data information generating module 130 generates airborne InSAR data information according to the echo scattering data, the airborne InSAR data information comprises data information of a main image and data information of an auxiliary image, the data information of the main image and the auxiliary image comprises SLC data, IMG data and POS data of each scene image, and interference parameters of each scene image are obtained through POS data calculation; after the data information of the main image and the auxiliary image is obtained, the main image and the auxiliary image are processed in real time through the data information processing module 140.

The data information processing module 140 includes an interference processing module 141, an interference scaling module 142, a block adjustment module 146, a geocoding module 143, a mosaic module 144 and a standard framing module 145, when the main image and the auxiliary image are processed in real time, the interference processing module 141 registers the SLC data of the main image and the auxiliary image according to the IMG data, generating an interference pattern and a coherent pattern according to the SLC data of the registered primary and secondary images, filtering the interference pattern, performing phase unwrapping on the filtered interference pattern, because the phase noise exists in the interferogram due to factors such as thermal noise, time and geometric decorrelation, doppler centroid decorrelation and the like of the system, the interferogram needs to be filtered before phase unwrapping, therefore, the influence of phase noise on the precision and the calculation efficiency of phase unwrapping and the subsequent interference measurement precision is avoided. In an actual situation, the interference of most of the carrier images has a large error, and a high-precision DEM cannot be generated, so that the interference parameters of the images need to be calibrated, that is, the interference parameter deviation of the images is strictly corrected.

After the corrected interference parameters of each scene image are obtained, the elevation information of each image point is required to be obtained, the elevation information of each image point on the image is obtained through phase-to-height conversion by using POS data and the corrected interference parameters through the geocoding module 143, then the coordinates of each image point on the Gaussian plane are obtained through the geometric relation, the geographic coordinates are formed according to the elevation information of each image point and the coordinates of each image point on the Gaussian plane, resampling is performed according to the geographic coordinates, the elevation information and the gray value of the image are assigned to the resampled image points, and the DEM and the DOM meeting the precision requirement are generated. After the DEM and the DOM are generated, all adjacent DEMs in the measuring area are spliced and embedded through a splicing and embedding module 144 to form a DEM block diagram; splicing and embedding all adjacent DOM in the measuring area to form a DOM module diagram; it should be noted that when the DEM and the DOM are spliced and embedded to form the module diagram, the influence tones on both sides of the embedding line need to be adjusted at the same time, so that there is no obvious splicing or embedding trace between two adjacent images. Then, standard framing is carried out on the DEM module diagram and the DOM module diagram through a standard framing module 145, the DEM module diagram and the DOM module diagram are cut according to a preset scale, the length and the width of the breadth, the coordinates of the corner points in the southwest direction and the latitude and longitude intervals, and the DEM diagram and the DOM diagram which accord with the basic national scale are generated; before the carrier lands, the DEM graph and the DOM graph which accord with the national basic scale are transmitted to a ground station or an individual user in real time through the image transmission module 150.

According to the rapid real-time processing system for the airborne InSAR data, provided by the embodiment of the application, after the airborne machine receives the ground echo scattering data, the rapid, real-time and automatic data processing can be carried out on the airborne machine, and the processed DEM and DOM which meet the national standard scale can be transmitted to a ground workstation or a personal user before or after the aircraft lands, so that the efficiency of data processing and transmission can be improved, and the user requirements can be better met; in the data processing process, after the interferogram is generated, the interferogram is filtered and then subjected to phase unwrapping, so that the influence of phase noise in the interferogram on the phase unwrapping precision, the calculation efficiency and the subsequent interferometric measurement precision can be avoided; the interference parameters are calibrated by the block adjustment method, the interference parameter deviation of the images can be strictly corrected, and accurate interference parameters after the images of all scenes are corrected are obtained, so that the DEM and DOM generation precision can be improved, the constraint relation between the images is established by the block adjustment method, the inversion height difference at the joint can be reduced, and the overall consistency and continuity of the DEM and the DOM are enhanced; in addition, this application is through the electromagnetic wave of loader antenna transmission and receiving ground echo scattered data, does not receive the weather influence, can realize all-weather, carry out ground echo data acquisition all day time to make DEM and DOM's extraction more nimble.

Optionally, the interference calibration module is configured to extract a pixel coordinate and a unwrapping phase of the ground control point on the image in the measurement area according to the coordinate information of the ground control point, and generate an image control point file; the method is also used for inputting image control point files and POS data, and scaling is carried out by adopting a method based on a sensitivity equation, wherein the sensitivity equation is expressed as: Δ ═ F × Δ x + M, where Δ is an elevation deviation value of a ground control point, F is a sensitivity matrix, Δ x is an interference parameter deviation to be estimated, and M is noise; the interference parameter correction module is also used for correcting the interference parameters to be calibrated according to the deviation of the interference parameters to be estimated to obtain the corrected interference parameters of each scene image; wherein the interference parameters at least include phase offset, baseline length, baseline tilt angle and time delay.

Specifically, when calculating the interference parameters after correcting each scene image, the interference calibration module 142 may calculate by using an interference parameter calibration method based on a sensitivity equation, and differentiate the basic target positioning equation by using different interference parameters to form an interference parameter sensitivity equation, and establish a relationship between a target function and interference parameter deviations, that is, each differential equation indicates the influence sensitivity of the interference parameter on the target positioning error, so that interference calibration may be performed based on a sensitivity equation Δ ═ F Δ x + M, where Δ is an elevation deviation value of a ground control point, F is a sensitivity matrix, Δ x is an interference parameter deviation to be estimated, and M is noise, and reasonable ground control points are distributed through a plurality of positions to form a sensitivity equation set, and an estimation value of each interference parameter deviation is calculated by solving the equation set, and then the interference parameters are corrected by using the estimation value of the interference parameter deviation, and the corrected interference parameters are applied to carry out target three-dimensional reconstruction, so that the DEM precision is improved. It should be noted that, when the interference parameter correction is performed, iterative computation needs to be performed for multiple times, and after the interference parameter is corrected by using the estimated value of the interference parameter deviation each time, the DEM needs to be recalculated according to the corrected interference parameter, and it is determined whether the mean square deviation of the ground elevation calculated in the previous and subsequent times reaches the ideal precision, and after the mean square deviation of the ground elevation calculated in the previous and subsequent times reaches the ideal precision, the iteration is stopped, and the latest corrected interference parameter is used as the final corrected interference parameter.

Optionally, the block adjustment module is configured to automatically select a connection point in an overlapping area of each scene image, and obtain the corrected interference parameter and the three-dimensional coordinate of the connection point through adjustment calculation according to initial coordinate information of the ground control point and the connection point.

Specifically, when calculating the corrected interference parameters of each scene image, selecting connection points in the overlapped area of each scene image through the block adjustment module 146, wherein the selected connection points are uniformly distributed, the number of the connection points and the number of the control points are required to meet the block adjustment requirement, the selected connection points can be selected in the flight band or in the flight band, the overlapping degree of each scene image in the flight band is about 10%, and when selecting the connection points in the flight band, a row of connection points are uniformly selected in the middle of the overlapped part of each image in the flight band; the overlap degree between the flight belts is about 30%, and when the connection points are selected between the flight belts, two rows of connection points are uniformly selected near the overlapped parts of the adjacent flight belts. It should be noted that, when a connection point is selected, the onboard InSAR data real-time processing system 100 provided in the embodiment of the present application further has functions of deleting the connection point and emptying the connection point, and when the connection point needs to be deleted or emptied, the deletion or emptying operation is performed.

After the connection points are selected, according to initial coordinate information of a small number of control points and the connection points, elevation area network adjustment and plane area network adjustment are carried out, and two types of unknowns, namely correction values of exterior orientation elements in elevation of each image and correction values of coordinates of the connection points, are alternately approximated and calculated. When the elevation regional net adjustment is calculated, the correction value of each external orientation element of the elevation of each scene image is obtained according to the initial value of the external orientation element of the elevation of each scene image and the initial value of the elevation coordinate of the connecting point, the initial value and the correction value are added to obtain the external orientation element of the elevation of each scene image, then the elevation coordinate of the connecting point is calculated according to the external orientation element of the elevation of each scene image, and repeated iterative calculation is carried out until the difference value of the elevation coordinates of the front and the back two times is smaller than the set threshold value. And after the leveling of the elevation area network is finished, performing leveling of the plane area network, wherein the step of leveling of the plane area network is the same as that of the elevation area network, and the details are not repeated here. When the elevation block adjustment and the plane block adjustment are performed, after coordinate information of an exterior orientation element and a connection point of each scene image is obtained through pre-adjustment calculation, the exterior orientation element of each scene image includes an elevation coordinate and a plane coordinate of each scene image, coarse adjustment detection needs to be performed on the connection point and the control point, coarse adjustment points in the connection point and the control point are eliminated or corrected, then the control point and the connection point with the coarse adjustment points eliminated are used for performing elevation and plane block adjustment calculation, the coarse adjustment points in the connection point and the control point are eliminated before the block adjustment is performed, and therefore accuracy and precision of adjustment calculation are improved.

It should be noted that the onboard InSAR data real-time processing system 100 provided in the embodiment of the present application includes, in addition to the above modules, a basic processing module 160, and processes and analyzes the remote sensing data through the basic processing module 160, such as data reading, scaling control, basic geographic information overlay display, image restoration, undo/redo, curve adjustment, histogram equalization and color gradation, image filtering, image enhancement, profile display, information window, image linkage, and the like, and reads onboard InSAR image data and meta information data, and process and product data according to onboard InSAR load data format definition; the current image data can be subjected to zoom control, the superposition display of a plurality of vector files and the remote sensing image data is supported, and if the current displayed image does not meet the requirements, the image can be cancelled or redone; the curve adjusting function is used for adjusting the tone of the image, such as highlight, shadow and the like of the image, and when the tone of the image is adjusted, each independent color channel can be adjusted, and multi-channel adjustment can be integrated; the image enhancement function is realized, the image enhancement display is realized, the image display quality is improved, and the image information content is enriched, so that the image interpretation and identification effects are enhanced, and the application is facilitated; the image filtering function is used for inhibiting the noise of the target image under the condition of keeping the detail characteristics of the image as much as possible; the percentage pull-up can realize the pull-up of 1% and 2% of image histograms; the segmented color filling function can make the data after phase unwrapping or DEM data into colors; the profile display function may obtain an X, Y profile at each point as well as a grayscale; the information window can display pixel information of the mouse, can select a waveband and realize the eagle eye view and the coordinate scale to display an image; the image linkage can realize linkage display of main and auxiliary images, check the image registration effect, and also can perform linkage display of phase data and product data to check whether the product data is correct.

According to the embodiment, the method and the system for rapidly processing the airborne InSAR data in real time at least realize the following beneficial effects:

Although some specific embodiments of the present invention have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are for illustrative purposes only and are not intended to limit the scope of the present invention. It will be appreciated by those skilled in the art that modifications may be made to the above embodiments without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.

Claims

1. A quick real-time processing method of airborne InSAR data is characterized by comprising the following steps:

registering the SLC data of the primary image and the secondary image according to the IMG data; generating an interference graph and a coherence graph according to the registered main image SLC data and auxiliary image SLC data; filtering the interference pattern by using minimum balance treeAnd performing phase unwrapping on the processed interferogram to obtain an unwrapped phase map, which specifically comprises the following steps: detecting a phase residual error point source according to a quality weight factor Q of a winding phase, and defining the reliability index of a positive residual error point as P at (x, y)⁺＝min{P_S(x，y)|S∈R⁺The reliability index of the negative residual point is P^-＝min{P_S(x，y)|S∈R^-P, defining dual reliability index as P, P (x, y) ═ P⁺(x，y)+P^-(x, y); forming a phase continuity reliability graph according to the reliability index, determining a minimum reliable residual point pair, and defining a connecting line

According to the minimum reliable residual error point pair, carrying out discontinuous boundary tracking to construct a minimum balanced tree; wherein R is⁺And R^-Positive and negative residual error point sets; the most reliable phase point is detected from the phase continuity reliability map, and the most reliable path l from the reference point to the target point is represented as

Taking the most reliable integral path as a priority F at (x, y), and determining an unwrapping sequence according to the priority F, wherein F (x, y) is min { P (x, y) | (x, y) ∈ l }; performing phase unwrapping according to the minimum balance tree and unwrapping sequence;

2. The method for fast real-time processing of airborne InSAR data according to claim 1, wherein the registering of SLC data of the primary and secondary images according to IMG data is specifically: calculating the relative offset of the matching position between the SLC complex data of the main image and the auxiliary image, calculating the coordinate conversion relation between the SLC complex data of the main image and the auxiliary image according to the relative offset of the matching position, and resampling the SLC data of the auxiliary image.

3. The method for fast real-time processing of airborne InSAR data according to claim 1, characterized in that the filtering process is performed on the interferogram, specifically: the method adopts a complex interference pattern self-adaptive filtering method combining median filtering and power spectrum weighting.

4. The method for rapidly processing the airborne InSAR data in real time according to claim 1, wherein the interference parameters of the images are calibrated through interference calibration, and the corrected interference parameters of the images of each scene are calculated, specifically: extracting pixel coordinates and unwrapping phases of the ground control points in the measuring area on the image according to the coordinate information of the ground control points to generate an image control point file; inputting the image control point file and the POS data, and calibrating by adopting a method based on a sensitivity equation, wherein the sensitivity equation is expressed as: Δ ═ F × Δ x + M, where Δ is an elevation deviation value of a ground control point, F is a sensitivity matrix, Δ x is an interference parameter deviation to be estimated, and M is noise;

5. The method for rapidly processing the airborne InSAR data in real time according to claim 1, wherein the step of calibrating the interference parameters of the images through block adjustment and calculating the corrected interference parameters of the images of each scene specifically comprises the following steps: and automatically selecting a connecting point in the overlapping area of each scene image, and obtaining corrected interference parameters and three-dimensional coordinates of the connecting point through adjustment calculation according to the initial coordinate information of the ground control point and the connecting point.

6. A fast real-time processing system of airborne InSAR data is characterized by comprising: the system comprises a control point uploading module, an antenna, a data information generating module, a data information processing module and an image transmission module;

the interference processing module is used for processing the interference according to IMGData registering SLC data of the primary and secondary images; the interference image and the coherence image are generated according to the registered main image SLC data and auxiliary image SLC data; the phase unwrapping method is further used for filtering the interferogram and performing phase unwrapping on the interferogram after filtering by adopting a minimum balance tree to obtain an unwrapped phase map, and specifically comprises the following steps: detecting a phase residual error point source according to a quality weight factor Q of a winding phase, and defining the reliability index of a positive residual error point as P at (x, y)⁺＝min{P_S(x，y)|S∈R⁺The reliability index of the negative residual point is P^-＝min{P_S(x，y)|S∈R^-P, defining dual reliability index as P, P (x, y) ═ P⁺(x，y)+P^-(x, y); forming a phase continuity reliability graph according to the reliability index, determining a minimum reliable residual point pair, and defining a connecting line

7. The system for fast real-time processing of airborne InSAR data according to claim 6, wherein the interferometric calibration module is configured to extract pixel coordinates and unwrapping phases of the ground control points on the image in the measurement area according to the coordinate information of the ground control points, and generate an image control point file; and the POS terminal is also used for inputting the image control point file and the POS data, and calibrating by adopting a method based on a sensitivity equation, wherein the sensitivity equation is expressed as: Δ ═ F × Δ x + M, where Δ is an elevation deviation value of a ground control point, F is a sensitivity matrix, Δ x is an interference parameter deviation to be estimated, and M is noise;

8. The system of claim 6, wherein the block adjustment module is configured to automatically select a connection point in an overlapping area of each scene image, and obtain corrected interference parameters and three-dimensional coordinates of the connection point through adjustment calculation according to initial coordinate information of the ground control point and the connection point.