CN104966294B - Based on Polarimetric SAR Image matching process and the device of orientation angle inverting - Google Patents

Abstract

The invention discloses a kind of Polarimetric SAR Image matching process based on orientation angle inverting and device, wherein, method comprises the following steps: obtain dem data and polarization SAR data; Inverting is carried out, to obtain the first orientation angle according to described dem data; Inverting is carried out, to obtain the second orientation angle according to described SAR data; Respectively visualization processing is carried out to described first orientation angle and described second orientation angle; By BFSIFT algorithm, the first orientation angle after visualization processing and the second orientation angle are mated.According to the matching process of the embodiment of the present invention, by based on the Polarimetric SAR Image of orientation angle inverting and DEM coupling, reduce match time, improve computing accuracy rate, not only computational complexity is low, and high with computing stability.

Description

Based on Polarimetric SAR Image matching process and the device of orientation angle inverting

Technical field

The present invention relates to image matching guidance technical field, particularly a kind of Polarimetric SAR Image matching process based on orientation angle inverting and device.

Background technology

The result that existing SAR (SyntheticApertureRadar, synthetic-aperture radar) image matching algorithm mates mountain area is poor.Because SAR is the imaging of side-looking oblique distance, when ground exists height relief, will there is the geometric distortions such as facing slope reduction, back slope stretching, shade and top end inversion in Range Profile.Therefore, when the imaging region floor level big rise and fall of two width SAR image and imaging geometry structure is different time, will serious geometric deformation be there is therebetween, sometimes even by human eye all None-identified be the same area.This phenomenon is particularly serious when low latitude imaging, brings great difficulty to mountain area SAR image coupling.For San Francisco area, Fig. 1 gives the result of the polarization SAR general power image use SIFT algorithmic match of different incident direction.Wherein, with reference to shown in Fig. 1, the incident direction of left-side images is from top to bottom, the incident direction of image right is from left to right, in comparison diagram, left and right two width figure can find out, the urban area that topographic relief is less presents good similarity, obtains more match point; And the mountain area that square frame mesorelief is larger, present very serious geometric deformation, there is no match point.For mountain area, DEM (DigitalElevationModel, digital elevation model) is the most stable feature.

Wherein, best means DEM and polarization SAR data being carried out contacting are orientation angles.Polarization SAR can carry out inverting DEM by orientation angle.1996, the orientation angle of the people such as Schuler to Polarimetric SAR Image calculated, and carries out the measurement of landform with it.2000, the people such as Schuler by utilizing the polarization SAR data inversion orientation angle repeatedly flown, and then carried out the measurement of landform to mountain region.Domestic also have much the research that polarization SAR carries out orientation angle and DEM inverting.2004, Jin Yaqiu academician is when obtaining single flight SAR data, as Morphological Thinning Algorithm, the image texture that the arrangement of proposition declined ground level orientation produces determines that level orientation is to angle, and then determine that orientation is to the gradient and distance to the gradient, realizes the inverting of DEM.2009, the people such as Chen were by achieving the inverting of DEM in conjunction with orientation angle and shape-from-shading technology.

2004, Lowe, on the basis of existing invariant technical characteristic detection method, proposed SIFT (ScareInvariantFeatureTransform) algorithm.This is a kind of Feature Correspondence Algorithm image scaling, rotation and affined transformation to unchangeability.This algorithm has very strong matching capacity, processes affine, the visual angle between image, the matching problem under light change by extracting invariant feature.In recent years, SIFT conversion is also used to the coupling of SAR image.Because SAR image has very strong speckle noise, SIFT algorithm is easy to get the key point of mistake, causes that it fails to match.For non-homogeneous SAR image, matching rate is usually very low, and this is also the major issue that SIFT algorithm faces in SAR scene matching aided navigation.

Summary of the invention

The application makes the understanding of following problem and discovery based on inventor:

Due under different visual angles, the scattering matrix of Polarimetric SAR Image is all different.And the geometric distortion that mountain area SAR image is intrinsic, such as facing slope reduction, back slope stretch and the inversion of the end, top, cause mountain area SAR scene matching aided navigation to become very difficult

The present invention is intended to solve one of technical matters in above-mentioned correlation technique at least to a certain extent.

For this reason, one object of the present invention is to propose a kind of Polarimetric SAR Image matching process based on orientation angle inverting, and the method can solve the problem of mountain area through scene matching aided navigation difficulty, improves matching effect.

Another object of the present invention is to propose a kind of Polarimetric SAR Image coalignment based on orientation angle inverting.

For achieving the above object, one aspect of the present invention embodiment proposes a kind of Polarimetric SAR Image matching process based on orientation angle inverting, comprises the following steps: obtain dem data and polarization SAR data; Inverting is carried out, to obtain the first orientation angle according to described dem data; Inverting is carried out, to obtain the second orientation angle according to described SAR data; Respectively visualization processing is carried out to described first orientation angle and described second orientation angle; And by BFSIFT algorithm, the first orientation angle after visualization processing and the second orientation angle are mated.

According to the Polarimetric SAR Image matching process based on orientation angle inverting that the embodiment of the present invention proposes, by the orientation angle by dem data and polarization SAR data acquisition is carried out visualization processing, mate to utilize BFSIFT algorithm, thus solve SAR image in the registration problems of topographic relief compared with large regions such as mountain area, from this mountain area invariant feature of DEM, realize the coupling of Polarimetric SAR Image and DEM, not only reduce match time, improve computing accuracy rate, and computational complexity is low, computing stability is high.

In addition, the Polarimetric SAR Image matching process based on orientation angle inverting according to the above embodiment of the present invention can also have following additional technical characteristic:

Further, in one embodiment of the invention, when carrying out inverting according to described dem data, described first orientation angle and orientation to the gradient and distance to the relational expression of the gradient are:

Wherein, ψ is the orientation angle produced by the gradient, and φ is the illumination angle of radar line of sight, tan γ be described distance to the gradient, tan β is that described orientation is to the gradient.

Further, in one embodiment of the invention, by the orientation angle inversion algorithm based on circular polarisation base, inverting is carried out to described SAR data.

Further, in one embodiment of the invention, respectively described first orientation angle and described second orientation angle are mapped to pre-set image interval, to realize visualization processing by linear transformation.

Further, in one embodiment of the invention, described pre-set image interval can be that [01] is interval.

The present invention on the other hand embodiment proposes a kind of Polarimetric SAR Image coalignment based on orientation angle inverting, comprising: acquisition module, for obtaining dem data and polarization SAR data; First inverting module, for carrying out inverting according to described dem data, to obtain the first orientation angle; Second inverting module, for carrying out inverting according to described SAR data, to obtain the second orientation angle; Visualization model, for carrying out visualization processing to described first orientation angle and described second orientation angle respectively; And matching module, for being mated the first orientation angle after visualization processing and the second orientation angle by BFSIFT algorithm.

According to the Polarimetric SAR Image coalignment based on orientation angle inverting that the embodiment of the present invention proposes, by the orientation angle by dem data and polarization SAR data acquisition is carried out visualization processing, mate to utilize BFSIFT algorithm, thus solve SAR image in the registration problems of topographic relief compared with large regions such as mountain area, from this mountain area invariant feature of DEM, realize the coupling of Polarimetric SAR Image and DEM, not only reduce match time, improve computing accuracy rate, and computational complexity is low, computing stability is high.

In addition, the Polarimetric SAR Image coalignment based on orientation angle inverting according to the above embodiment of the present invention can also have following additional technical characteristic:

Further, in one embodiment of the invention, when carrying out inverting according to described dem data, described first orientation angle and orientation to the gradient and distance to the relational expression of the gradient are:

$tan\mathrm{\ψ}=\frac{tan\mathrm{\β}}{sin\mathrm{\φ}-cos\mathrm{\φ}tan\mathrm{\γ}},$

Wherein, ψ is the orientation angle produced by the gradient, and φ is the illumination angle of radar line of sight, tan γ be described distance to the gradient, tan β is that described orientation is to the gradient.

Further, in one embodiment of the invention, described second inverting module is used for carrying out inverting by the orientation angle inversion algorithm based on circular polarisation base to described SAR data.

Further, in one embodiment of the invention, described visualization model is also for mapping to pre-set image interval, to realize visualization processing by described first orientation angle and described second orientation angle respectively by linear transformation.

Further, in one embodiment of the invention, described pre-set image interval can be that [01] is interval.

The aspect that the present invention adds and advantage will part provide in the following description, and part will become obvious from the following description, or be recognized by practice of the present invention.

Accompanying drawing explanation

Above-mentioned and/or additional aspect of the present invention and advantage will become obvious and easy understand from accompanying drawing below combining to the description of embodiment, wherein:

Fig. 1 is the otherness schematic diagram of the Polarimetric SAR Image matching effect of different incident direction in correlation technique;

Fig. 2 is the process flow diagram of the Polarimetric SAR Image matching process based on orientation angle inverting according to the embodiment of the present invention;

Fig. 3 is according to an embodiment of the invention based on the process flow diagram of the Polarimetric SAR Image matching process of orientation angle inverting;

Fig. 4 is the process flow diagram of BFSIFT algorithm according to an embodiment of the invention;

Fig. 5 carries out the result schematic diagram of mountain area scene matching aided navigation for using TopSAR data (ts545 and ts555) according to an embodiment of the invention;

Fig. 6 carries out the result schematic diagram of mountain area scene matching aided navigation for using TopSAR data (ts555 and ts554) according to an embodiment of the invention; And

Fig. 7 is the structural representation of the Polarimetric SAR Image coalignment based on orientation angle inverting according to the embodiment of the present invention.

Embodiment

Be described below in detail embodiments of the invention, the example of described embodiment is shown in the drawings, and wherein same or similar label represents same or similar element or has element that is identical or similar functions from start to finish.Be exemplary below by the embodiment be described with reference to the drawings, be intended to for explaining the present invention, and can not limitation of the present invention be interpreted as.

In addition, term " first ", " second " only for describing object, and can not be interpreted as instruction or hint relative importance or imply the quantity indicating indicated technical characteristic.Thus, be limited with " first ", the feature of " second " can express or impliedly comprise one or more these features.In describing the invention, the implication of " multiple " is two or more, unless otherwise expressly limited specifically.

In the present invention, unless otherwise clearly defined and limited, the term such as term " installation ", " being connected ", " connection ", " fixing " should be interpreted broadly, and such as, can be fixedly connected with, also can be removably connect, or connect integratedly; Can be mechanical connection, also can be electrical connection; Can be directly be connected, also indirectly can be connected by intermediary, can be the connection of two element internals.For the ordinary skill in the art, above-mentioned term concrete meaning in the present invention can be understood as the case may be.

In the present invention, unless otherwise clearly defined and limited, fisrt feature second feature it " on " or D score can comprise the first and second features and directly contact, also can comprise the first and second features and not be directly contact but by the other characterisation contact between them.And, fisrt feature second feature " on ", " top " and " above " comprise fisrt feature directly over second feature and oblique upper, or only represent that fisrt feature level height is higher than second feature.Fisrt feature second feature " under ", " below " and " below " comprise fisrt feature immediately below second feature and tiltedly below, or only represent that fisrt feature level height is less than second feature.

Describe the Polarimetric SAR Image matching process based on orientation angle inverting and device that propose according to the embodiment of the present invention with reference to the accompanying drawings, describe the Polarimetric SAR Image matching process based on orientation angle inverting proposed according to the embodiment of the present invention first with reference to the accompanying drawings.With reference to shown in Fig. 2, this matching process comprises the following steps:

S101, obtains dem data and polarization SAR data.

In one embodiment of the invention, with reference to shown in Fig. 3, respectively according to reference data and data acquisition dem data to be matched and polarization SAR data.

S102, carries out inverting according to dem data, to obtain the first orientation angle.

Wherein, in one embodiment of the invention, when carrying out inverting according to dem data, the first orientation angle and orientation to the gradient and distance to the relational expression of the gradient such as formula shown in (1):

$tan\mathrm{\ψ}=\frac{tan\mathrm{\β}}{sin\mathrm{\φ}-cos\mathrm{\φ}tan\mathrm{\γ}}---\left(1\right)$

Wherein, ψ is the orientation angle produced by the gradient, and φ is the illumination angle of radar line of sight, tan γ be distance to the gradient, tan β is that orientation is to the gradient.Particularly, distance directly can be calculated by DEM to orientation to the gradient, then can be finally inversed by with reference to orientation angle, i.e. the first orientation angle in conjunction with the illumination angle of radar line of sight.

S103, carries out inverting according to SAR data, to obtain the second orientation angle.

Wherein, in one embodiment of the invention, by the orientation angle inversion algorithm based on circular polarisation base, inverting is carried out to SAR data.

Particularly, with reference to shown in Fig. 3, the real-time orientation angle of polarization SAR data inversion is used, i.e. the second orientation angle.

From the definition of orientation angle, orientation angle can cause the rotation of polarization SAR matrix, shown in (2).Can say, orientation angle is hidden in measurement and obtains in polarization SAR data.

$\tilde{S}=\left[\begin{array}{cc}cos\mathrm{\θ}& sin\mathrm{\θ}\\ -sin\mathrm{\θ}& cos\mathrm{\θ}\end{array}\right]S\left[\begin{array}{cc}cos\mathrm{\θ}& -sin\mathrm{\θ}\\ sin\mathrm{\θ}& \cos \mathrm{\θ}\end{array}\right]---\left(2\right)$

Wherein, θ is orientation angle, and S is the Sinclair matrix before rotating, for postrotational Sinclair matrix.

When reciprocal theorem meets, under circular polarisation base, three elements of polarization scattering matrix and horizontal vertical polarize and to polarize the relation of three elements of matrix under base as shown in (3).

S _RR＝(S _HH-S _VV+i2S _HV)/2

S _LL＝(S _VV-S _HH+i2S _HV)/2(3)

S _RL＝i(S _HH+S _VV)/2

Three elements of matrix of polarizing under postrotational circular polarisation base can be expressed as:

$\begin{array}{c}{\tilde{S}}_{RR}=S_{RR}{e}^{-i2\mathrm{\θ}}\\ {\tilde{S}}_{LL}=S_{LL}{e}^{i2\mathrm{\θ}}\\ {\tilde{S}}_{RL}=S_{RL}\end{array}---\left(4\right)$

Correlation matrix under circular polarisation base so after corresponding rotation is:

$\begin{array}{c}\tilde{C}=\left[\begin{array}{ccc}{\tilde{S}}_{RR}{\tilde{S}}_{RR}^{*}& \sqrt{2}{\tilde{S}}_{RR}{\tilde{S}}_{RL}^{*}& {\tilde{S}}_{RR}{\tilde{S}}_{LL}^{*}\\ \sqrt{2}{\tilde{S}}_{RL}{\tilde{S}}_{RR}^{*}& 2{\tilde{S}}_{RL}{\tilde{S}}_{RL}^{*}& \sqrt{2}{\tilde{S}}_{RL}{\tilde{S}}_{LL}^{*}\\ {\tilde{S}}_{LL}{\tilde{S}}_{RR}^{*}& \sqrt{2}{\tilde{S}}_{LL}{\tilde{S}}_{RL}^{*}& {\tilde{S}}_{LL}{\tilde{S}}_{LL}^{*}\end{array}\right]\\ =\left[\begin{array}{ccc}{S}_{RR}{S}_{RR}^{*}& \sqrt{2}\left(S_{RL}{S}_{RL}^{*}\right)e^{-i2\mathrm{\θ}}& \left(S_{RR}{S}_{LL}^{*}\right)e^{-i4\mathrm{\θ}}\\ \sqrt{2}\left(S_{RL}{S}_{RL}^{*}\right)e^{i2\mathrm{\θ}}& 2S_{RL}{S}_{RL}^{*}& \sqrt{2}\left(S_{RL}{S}_{RL}^{*}\right)e^{i2\mathrm{\θ}}\\ \left(S_{LL}{S}_{RR}^{*}\right)e^{-i4\mathrm{\θ}}& \sqrt{2}\left(S_{RL}{S}_{RL}^{*}\right)e^{-i2\mathrm{\θ}}& S_{LL}{S}_{LL}^{*}\end{array}\right]\end{array}---\left(5\right)$

Observe the tertial element of the first row:

${\tilde{S}}_{RR}{\tilde{S}}_{LL}^{*}=\left(S_{RR}{S}_{LL}^{*}\right)e^{-i4\mathrm{\θ}}---\left(6\right)$

When for reflective symmetry medium, $S_{HH}{S}_{HV}^{*}=0,S_{VV}{S}_{HV}^{*}=0.$ Bring formula into formula (7) can be obtained. for real number, be not introducing phase place changes, namely phase place be-4 θ.The span of known θ is [-π/4, π/4].

$S_{RR}{S}_{LL}^{*}=\frac{-|S_{HH}-S_{VV}{|}^2+4|S_{HV}{|}^2}{4}---\left(7\right)$

${\tilde{S}}_{RR}{\tilde{S}}_{LL}^{*}=\frac{1}{4}\[-|{\tilde{S}}_{HH}-{\tilde{S}}_{VV}{|}^2+4|{\tilde{S}}_{HV}{|}^2\]-i4\mathrm{Re}\[({\tilde{S}}_{HH}-{\tilde{S}}_{\mathrm{VV}}){\tilde{S}}_{HV}\]---\left(8\right)$

Can obtain thus:

$\begin{array}{c}\mathrm{\θ}=-\frac{1}{4}Arg\left({\tilde{S}}_{RR}{\tilde{S}}_{LL}^{*}\right)\\ =-\frac{1}{4}{\tan }^{-1}\left(\frac{-\mathrm{Re}\[({\tilde{S}}_{HH}-{\tilde{S}}_{VV}){\tilde{S}}_{HV}^{*}\]}{-|{\tilde{S}}_{HH}-{\tilde{S}}_{VV}{|}^2+4|{\tilde{S}}_{HV}{|}^2}\right)\end{array}---\left(9\right)$

For azimuthal symmetry medium, above formula can not be directly used in and ask orientation angle.Under normal circumstances much larger than namely denominator is negative.When molecule is tending towards 0, θ will be tending towards ± π/4, and in fact now orientation angle should be tending towards 0.In order to θ is corresponding with orientation angle, adjust as follows:

$\mathrm{\θ}=\left\{\begin{array}{cc}\mathrm{\η}& (\mathrm{\η}\≤\mathrm{\π}/4)\\ \mathrm{\η}-\mathrm{\π}/2& (\mathrm{\η}>\mathrm{\π}/4)\end{array}\right.---\left(10\right)$

Wherein:

$\mathrm{\η}=-\frac{1}{4}\{{\tan }^{-1}\left(\frac{-\mathrm{Re}\[({\tilde{S}}_{HH}-{\tilde{S}}_{VV}){\tilde{S}}_{HV}^{*}\]}{-|{\tilde{S}}_{HH}-{\tilde{S}}_{VV}{|}^2+4|{\tilde{S}}_{HV}{|}^2}\right)+\mathrm{\π}\}---\left(11\right)$

S104, carries out visualization processing to the first orientation angle and the second orientation angle respectively.

Further, in one embodiment of the invention, respectively the first orientation angle and the second orientation angle are mapped to pre-set image interval, to realize visualization processing by linear transformation.

Wherein, in one embodiment of the invention, pre-set image interval is preferably [01] interval.

Particularly, with reference to shown in Fig. 3, visualization processing is carried out to reference to orientation angle and real-time orientation angle.

Further, the scope of orientation angle is [090], therefore can be mapped in [01] interval by orientation angle by simple linear transformation, realize visualization processing.

S105, is mated the first orientation angle after visualization processing and the second orientation angle by BFSIFT algorithm.

Particularly, with reference to shown in Fig. 3, to mating with reference to orientation angle and real-time orientation angle after visualization processing.

By the coupling of BFSIFT algorithm realization with reference to orientation angle and real-time orientation angle, i.e. the coupling of the first orientation angle and the second orientation angle.Wherein, BFSIFT algorithm also can be replaced by SIFT algorithm, but BFSIFT algorithm has noise immunity better.

Particularly, with reference to shown in Fig. 4, BFSIFT is feature based method for registering images, and the method for registering images basic procedure of feature based, comprises feature extraction, characteristic matching and conversion parametric solution three basic steps.BFSIFT algorithm extracts and is characterized as point patterns, extracts the point of graphical rule, rotation, translation invariance, and does corresponding description to unique point.Because feature interpretation is high-dimensional vector space Feature Points Matching, so adopt kd tree search algorithm to carry out characteristic matching.Conversion parametric solution adopts least-squares estimation, for making the conversion parameter optimum solved, adopts random consistent problem solving to convert parameter.

BFSIFT algorithm and classical matching algorithm SIFT difference are feature point detection, and have the unique point of graphical rule unchangeability for extracting, SIFT algorithm adopts Gaussian pyramid construction graphical rule space, Gaussian filter core such as formula:

$G\left(r\right)=\frac{1}{2{\mathrm{\π\σ}}^2}\exp (-\frac{r^2}{2{\mathrm{\σ}}^2}),$

Wherein σ scale factor.Metric space make such as formula, by adopting the filtering of different scale gaussian filtering core in different scale level, obtain several yardstick consecutive images.

L(x,y,σ)＝G(x,y,σ)*I(x,y)

Wherein G (x, y, σ) different scale gaussian filtering core, I (x, y) is image.

But due to the multiplicative noise characteristic of SAR image, when Gaussian filter builds metric space, its feature can be made to thicken to the smoothing effect that SAR image plays, be unfavorable for the extraction of subsequent characteristics, bidirectional filter BF core is because consider neighborhood and gray scale territory both direction simultaneously, and the metric space of its structure better can retain the feature of SAR image.Bidirectional filter core formula such as formula:

$BF(r,I)=\frac{1}{2{\mathrm{\π\σ}}_s{\mathrm{\σ}}_r}\exp (-\frac{r^2}{2{\mathrm{\σ}}_s^2})\exp \left(\right(-\frac{I^2}{{\mathrm{\σ}}_r^2}))$

Then adopt Laplace operator to extract the extreme points interested such as metric space angle point, marginal point to structure different scale images, adopt the unique point describing method consistent with SIFT algorithm and matching process to process accordingly.

In one particular embodiment of the present invention, experiment use three groups of data (ts545, ts554 and ts555), be on May 1st, 1998 TOPSAR and fly the distance data obtained, imaging area is CampRoberts.Ts554 and ts55 group packet is containing the polarization SAR data of C-band, the SAR data of L-band and the dem data of correspondence; Ts545 group packet contains the SAR data of C and L-band and corresponding dem data.Data in each group group, for obtain with flight, have identical image-forming condition and imaging region.With reference to shown in Fig. 5, in the drawings, a Polarimetric SAR Image matching result figure that () is L-band and C-band, namely the matching effect figure before the present invention is not used, b orientation angle matching result that () obtains for DEM and polarization SAR data inversion, namely uses the matching effect figure after the present invention.Similarly, with reference to shown in Fig. 6, in the drawings, a Polarimetric SAR Image matching result that () is L-band and C-band, namely the matching effect figure before the present invention is not used, b orientation angle matching result that () obtains for DEM and polarization SAR data inversion, uses the matching effect figure after the present invention.By Data Matching result 2 (these two groups of typical consequence schematic diagram of ts555 and ts554 that the Data Matching result 1 (ts545 and ts555) that the incident direction of Fig. 5 is vertical is vertical with the incident direction of Fig. 6, thus can find, to obviously be better than mating based on the Polarimetric SAR Image of Polarization scattering general power based on the Polarimetric SAR Image of orientation angle inverting and DEM matching effect.No matter be registration point or match time, the embodiment of the present invention all has obvious advantage.

In an embodiment of the present invention, with reference to shown in Fig. 5 and Fig. 6, after using matching process of the present invention, effective key that SIFT algorithm extracts is counted and is obviously increased, and the SIFT algorithmic match time obviously declines, and computational complexity is low, stability is high, and accuracy rate is high.Specifically as shown in table 1, table 1 is the images match outcome evaluation in Fig. 5 and Fig. 6.

Table 1

In one embodiment of the invention, the embodiment of the present invention, first according to the definition of orientation angle, is finally inversed by with reference to orientation angle simply by DEM; Secondly according to the orientation angle inversion algorithm based on circular polarisation base that the people such as Lee propose, real-time orientation angle inverting is carried out to polarization SAR data; Then by simple linear transformation, orientation angle is mapped in [01] interval, realizes visualization processing; Reference and the actual coupling obtaining the orientation angle of data is realized finally by BFSIFT.It is high that the embodiment of the present invention has matching precision, and algorithm speed is fast, can realize the feature of realtime graphic coupling.

According to the Polarimetric SAR Image matching process based on orientation angle inverting that the embodiment of the present invention proposes, by the orientation angle by dem data and polarization SAR data acquisition is carried out visualization processing, mate to utilize BFSIFT algorithm, thus solve SAR image in the registration problems of topographic relief compared with large regions such as mountain area, from this mountain area invariant feature of DEM, realize the coupling of Polarimetric SAR Image and DEM, not only reduce match time, improve computing accuracy rate, and computational complexity is low, computing stability is high.

Next describes the plan SAR image coalignment based on orientation angle inverting proposed according to the embodiment of the present invention with reference to the accompanying drawings.With reference to shown in Fig. 7, this coalignment 10 comprises: acquisition module 100, first inverting module 200, second inverting module 300, visualization model 400 and matching module 500.

Wherein, acquisition module 100 is for obtaining dem data and polarization SAR data.First inverting module 200 for carrying out inverting according to dem data, to obtain the first orientation angle.Second inverting module 300 for carrying out inverting according to SAR data, to obtain the second orientation angle.Visualization model 400 is for carrying out visualization processing to the first orientation angle and the second orientation angle respectively.Matching module 500 is for mating the first orientation angle after visualization processing and the second orientation angle by BFSIFT algorithm.The coalignment 10 of the embodiment of the present invention can by based on the Polarimetric SAR Image of orientation angle inverting and DEM coupling, and reduce match time, improve computing accuracy rate, not only computational complexity is low, and high with computing stability.

Further, in one embodiment of the invention, when carrying out inverting according to dem data, the first orientation angle and orientation to the gradient and distance to the relational expression of the gradient are:

$tan\mathrm{\ψ}=\frac{tan\mathrm{\β}}{sin\mathrm{\φ}-\cos \mathrm{\φ}tan\mathrm{\γ}},$

Wherein, ψ is the orientation angle produced by the gradient, and φ is the illumination angle of radar line of sight, tan γ be distance to the gradient, tan β is that orientation is to the gradient.

Particularly, distance directly can be calculated by DEM to orientation to the gradient, then can be finally inversed by with reference to orientation angle, i.e. the first orientation angle in conjunction with the illumination angle of radar line of sight.

Further, in one embodiment of the invention, with reference to shown in Fig. 7, the second inverting module 300 for carrying out inverting by the orientation angle inversion algorithm based on circular polarisation base to SAR data, to obtain real-time orientation angle, i.e. the second orientation angle.

Further, in one embodiment of the invention, with reference to shown in Fig. 7, visualization model 400 is also for mapping to pre-set image interval, to realize visualization processing by the first orientation angle and the second orientation angle respectively by linear transformation.

Further, in one embodiment of the invention, pre-set image interval can be that [01] is interval.

It should be noted that, the specific implementation of the device of the embodiment of the present invention and the specific implementation of method part similar, in order to reduce redundancy, do not repeat herein.

According to the Polarimetric SAR Image coalignment based on orientation angle inverting that the embodiment of the present invention proposes, by the orientation angle by dem data and polarization SAR data acquisition is carried out visualization processing, mate to utilize BFSIFT algorithm, thus solve SAR image in the registration problems of topographic relief compared with large regions such as mountain area, from this mountain area invariant feature of DEM, realize the coupling of Polarimetric SAR Image and DEM, not only reduce match time, improve computing accuracy rate, and computational complexity is low, computing stability is high.

Describe and can be understood in process flow diagram or in this any process otherwise described or method, represent and comprise one or more for realizing the module of the code of the executable instruction of the step of specific logical function or process, fragment or part, and the scope of the preferred embodiment of the present invention comprises other realization, wherein can not according to order that is shown or that discuss, comprise according to involved function by the mode while of basic or by contrary order, carry out n-back test, this should understand by embodiments of the invention person of ordinary skill in the field.

In flow charts represent or in this logic otherwise described and/or step, such as, the sequencing list of the executable instruction for realizing logic function can be considered to, may be embodied in any computer-readable medium, for instruction execution system, device or equipment (as computer based system, comprise the system of processor or other can from instruction execution system, device or equipment instruction fetch and perform the system of instruction) use, or to use in conjunction with these instruction execution systems, device or equipment.With regard to this instructions, " computer-readable medium " can be anyly can to comprise, store, communicate, propagate or transmission procedure for instruction execution system, device or equipment or the device that uses in conjunction with these instruction execution systems, device or equipment.The example more specifically (non-exhaustive list) of computer-readable medium comprises following: the electrical connection section (electronic installation) with one or more wiring, portable computer diskette box (magnetic device), random access memory (RAM), ROM (read-only memory) (ROM), erasablely edit ROM (read-only memory) (EPROM or flash memory), fiber device, and portable optic disk ROM (read-only memory) (CDROM).In addition, computer-readable medium can be even paper or other suitable media that can print described program thereon, because can such as by carrying out optical scanning to paper or other media, then carry out editing, decipher or carry out process with other suitable methods if desired and electronically obtain described program, be then stored in computer memory.

Should be appreciated that each several part of the present invention can realize with hardware, software, firmware or their combination.In the above-described embodiment, multiple step or method can with to store in memory and the software performed by suitable instruction execution system or firmware realize.Such as, if realized with hardware, the same in another embodiment, can realize by any one in following technology well known in the art or their combination: the discrete logic with the logic gates for realizing logic function to data-signal, there is the special IC of suitable combinational logic gate circuit, programmable gate array (PGA), field programmable gate array (FPGA) etc.

Those skilled in the art are appreciated that realizing all or part of step that above-described embodiment method carries is that the hardware that can carry out instruction relevant by program completes, described program can be stored in a kind of computer-readable recording medium, this program perform time, step comprising embodiment of the method one or a combination set of.

In addition, each functional unit in each embodiment of the present invention can be integrated in a processing module, also can be that the independent physics of unit exists, also can be integrated in a module by two or more unit.Above-mentioned integrated module both can adopt the form of hardware to realize, and the form of software function module also can be adopted to realize.If described integrated module using the form of software function module realize and as independently production marketing or use time, also can be stored in a computer read/write memory medium.

The above-mentioned storage medium mentioned can be ROM (read-only memory), disk or CD etc.

In the description of this instructions, specific features, structure, material or feature that the description of reference term " embodiment ", " some embodiments ", " example ", " concrete example " or " some examples " etc. means to describe in conjunction with this embodiment or example are contained at least one embodiment of the present invention or example.In this manual, identical embodiment or example are not necessarily referred to the schematic representation of above-mentioned term.And the specific features of description, structure, material or feature can combine in an appropriate manner in any one or more embodiment or example.

Although illustrate and describe embodiments of the invention above, be understandable that, above-described embodiment is exemplary, can not be interpreted as limitation of the present invention, those of ordinary skill in the art can change above-described embodiment within the scope of the invention when not departing from principle of the present invention and aim, revising, replacing and modification.

Claims (6)

1., based on a Polarimetric SAR Image matching process for orientation angle inverting, it is characterized in that, comprise the following steps:

Obtain dem data and polarization SAR data;

Carry out inverting according to described dem data, to obtain the first orientation angle, wherein, when carrying out inverting according to described dem data, described first orientation angle and orientation to the gradient and distance to the relational expression of the gradient are:

$tan\mathrm{\ψ}=\frac{tan\mathrm{\β}}{sin\mathrm{\φ}-cos\mathrm{\φ}tan\mathrm{\γ}},$

Wherein, ψ is the orientation angle produced by the gradient, and φ is the illumination angle of radar line of sight, tan γ be described distance to the gradient, tan β is that described orientation is to the gradient;

By the orientation angle inversion algorithm based on circular polarisation base, inverting is carried out to described SAR data, to obtain the second orientation angle;

Respectively visualization processing is carried out to described first orientation angle and described second orientation angle; And

By BFSIFT algorithm, the first orientation angle after visualization processing and the second orientation angle are mated.

2. the Polarimetric SAR Image matching process based on orientation angle inverting according to claim 1, is characterized in that, respectively described first orientation angle and described second orientation angle is mapped to pre-set image interval, to realize visualization processing by linear transformation.

3. the Polarimetric SAR Image matching process based on orientation angle inverting according to claim 2, is characterized in that, described pre-set image interval is that [01] is interval.

4., based on a Polarimetric SAR Image coalignment for orientation angle inverting, it is characterized in that, comprising:

Acquisition module, for obtaining dem data and polarization SAR data;

First inverting module, for carrying out inverting according to described dem data, to obtain the first orientation angle, wherein, when carrying out inverting according to described dem data, described first orientation angle and orientation to the gradient and distance to the relational expression of the gradient are:

$tan\mathrm{\ψ}=\frac{tan\mathrm{\β}}{sin\mathrm{\φ}-cos\mathrm{\φ}tan\mathrm{\γ}},$

Wherein, ψ is the orientation angle produced by the gradient, and φ is the illumination angle of radar line of sight, tan γ be described distance to the gradient, tan β is that described orientation is to the gradient;

Second inverting module, for carrying out inverting by the orientation angle inversion algorithm based on circular polarisation base to described SAR data, to obtain the second orientation angle;

Visualization model, for carrying out visualization processing to described first orientation angle and described second orientation angle respectively; And

Matching module, for mating the first orientation angle after visualization processing and the second orientation angle by BFSIFT algorithm.

5. the Polarimetric SAR Image coalignment based on orientation angle inverting according to claim 4, it is characterized in that, described visualization model is also for mapping to pre-set image interval, to realize visualization processing by described first orientation angle and described second orientation angle respectively by linear transformation.

6. the Polarimetric SAR Image coalignment based on orientation angle inverting according to claim 5, is characterized in that, described pre-set image interval is that [01] is interval.