CN101034472A - Landform transformation of satellite remote sensing digital image supported by GIS - Google Patents

Abstract

The invention relates to the satellite remotesensing digital picture terrain transformation under the GIS support. This method is: First,establishes the quotarelations digital principle model between satellite remote sensing information with the terrain, the solar direct light and the sky diffused light; Continues analysis satellite remote sensing digital picture: produces the solar direct light remote sensing picture and the sky diffused light remote sensing picture, separately carries on the terrain transformation, eliminates the radiation difference in the accidented relief and this kind of difference influence on the satellite remote sensing digital picture; then judges and eliminates the mountain body and the clouds layer shadow of remote sensing digital picture; finally completes the terrain transformation of the satellite remote sensing digital picture in this foundation. This invention theory, method is advanced, scientific, reasonable compare to the traditional remote sensing digital processing, widely applies to the quantitative investigation and the application of the remote sensing technology.

Description

The topographic change of the satellite remote sensing digital image under GIS supports

Technical field

The present invention relates to a kind of satellite remote sensing digital image disposal route, the topographic change method of the satellite remote sensing digital image under particularly GIS supports.

Background technology

Landform is to the elimination of the influence of satellite remote sensing digital image and massif shade, clouds layer shadow, always be satellite remote sensing digital image handle with use in a difficult problem.Existing satellite remote sensing digital image processing and application technology and orthography treatment technology all fundamentally do not solve this important problem.All do not have pertinent literature and patent report both at home and abroad through looking into new search, the topographic change of the satellite remote sensing digital image of this invention under GIS supports has solved this problem preferably from theory and practice.

Summary of the invention

The objective of the invention is to defective, the topographic change method of the satellite remote sensing digital image under the GIS support is provided at the prior art existence.

To achieve the above object of the invention, design of the present invention is:

This invention is to utilize direct sunlight in the nature, sky scattering illuminance, landform and satellite remote sensing digital image quantitative relationship each other under GIS supports, resolving original satellite remote sensing digital image is direct sunlight and sky scattering light remote sensing digital image.Utilize digital topography map to calculate pixel direct sunlight conversion (correction) coefficient on this basis, sky scattering light conversion (correction) coefficient and pixel terrestrial radiation parameter (scattering scattering/radiation ratio) are carried out the fractal transform flatly (as the satellite remote sensing digital image on the rugged topography being converted to respective satellite remote sensing digital image on the level ground) of direct sunlight and sky scattering light remote sensing digital image.

The elimination of shape shade and clouds layer shadow simultaneously, finish the topographic change of the satellite remote sensing digital image under the GIS support and the fractal transform at random of original satellite remote sensing digital image, make all strict some image-forming principle that quantitatively satisfies digital picture of each element remote sensing value.

According to above-mentioned inventive concept, the present invention adopts following technical proposals:

The topographic change method of the satellite remote sensing digital image under GIS supports is characterized in that:

At first, set up the mathematical model of quantitative relationship between satellite remote sensing information and landform, direct sunlight and the sky scattering light; The parsing satellite remote sensing digital image that continues: generate direct sunlight remote sensing images and sky scattering light remote sensing images, carry out topographic change respectively, the radiation difference on the elimination rugged topography and this species diversity are to the influence of satellite remote sensing digital image; Judge and eliminate the massif and the clouds layer shadow of remote sensing digital image then; Finish the topographic change of satellite remote sensing digital image on this basis at last.Theory of the present invention, the more traditional remote sensing digital processing of method advanced person, science, reasonable can be widely used in the quantitative examination and the application of remote sensing technology; Its concrete operations step is as follows:

(1), satellite remote sensing digital image and digital topography map registration;

(2), the Atmospheric corrections of satellite remote sensing digital image;

(3), each point sun altitude, azimuthal calculating on the satellite remote sensing digital image;

(4), calculate each point ground (domatic) direct sunlight topographic correction coefficient and ground (domatic) sky scattering light topographic correction coefficient on the satellite remote sensing digital image on the digital topography map:

(5), observe the scattering on the each point level ground/radiation ratio on measurement or the calculating satellite remote sensing digital image:

(6), resolve satellite remote sensing images; Generate direct sunlight remote sensing images and sky scattering light remote sensing images;

(7), the elimination of massif and clouds layer shadow on the judgement of massif and clouds layer shadow and the satellite remote sensing digital image on the satellite remote sensing digital image;

(8), the fractal transform flatly of direct sunlight remote sensing images and sky scattering light remote sensing images;

(9), the computing machine generation of digital picture is just being penetrated in shadow-free remote sensing;

(10), the fractal transform at random of remote sensing images.

Satellite remote sensing digital image and digital topography map registration in above-mentioned rapid (1) are the GIS routine operations.

The Atmospheric corrections of the satellite remote sensing digital image in the above-mentioned step (2) as follows suddenly step by step:

(1) utilizes ground surface reflectance γ 1 and the γ 2 defend adjacent two non-similar pixel DN1 and DN2 on the identical ground of sheet, be calculated as follows the pixel atmospheric path radiance remote sensing value that can obtain Discrete Distribution.

DN(a)＝γ1*(DN1-DN2)/(γ1-γ2) (1)

Perhaps the water body element remote sensing value in massif on the satellite remote sensing digital image and the clouds layer shadow is analyzed the pixel atmospheric path radiance remote sensing value that also can obtain Discrete Distribution;

(2), adopt interpolation algorithm to obtain each pixel atmospheric path radiance remote sensing value again to The above results;

To each pixel point remote sensing value DN on the satellite remote sensing digital image _IjDeduct atmospheric path radiance remote sensing value DN _AijComputing, i.e. DN _Ij-DN _Aij, just finished the Atmospheric corrections of satellite remote sensing digital image.

Wherein, DN _IjRepresent each pixel point remote sensing value on the satellite remote sensing digital image, DN _AijRepresent the atmospheric path radiance remote sensing value, DN _Ij-DN _AijRepresent the Atmospheric corrections value of satellite remote sensing digital image.

Each point sun altitude, azimuthal calculating are calculated by following formula on the satellite remote sensing digital image in the above-mentioned step (3):

θ _ij＝arcsin(sinφ*sinδ+cosφ*cosδ*cost(i，j)) (2)

A(i，j)＝arcsin(sinθ _ij*sinφ-sinδ)/cosθ _ij*cosφ) (3)

δ＝arcsin(sinθ*sinφ-cosθ*cosφ*cosA) (4)

t＝arcsin(cosθ _ij*sinA/cosδ)+Δλ (5)

θ, A, δ: defend substar sun altitude in the sheet annotation, position angle and sun Chi Jiao; λ, φ: be respectively the geographical longitude and latitude of substar.Δ λ is the longitude increment of pixel point to substar.

Massif is with as follows with the determination methods of clouds layer shadow on the satellite remote sensing digital image in the above-mentioned step (4):

Utilize digital topography map and the location parameter of defending the sun of sheet pixel with the satellite remote sensing digital image registration, be elevation angle, position angle, carry out the judgement of massif and clouds layer shadow, the criterion of its judgement is: the sun altitude that is equal to, or greater than this pixel point in the maximum landform, cloud layer, the elevation angle that shine upon this pixel point of direction promptly: DH (i, j) 〉=θ _Ij, then this pixel point is a shade; Otherwise then not shade.

Observation in the above-mentioned step (5) measure or calculate on the satellite remote sensing digital image on the each point level ground straight, the scattered radiation ratio method is as follows:

If defending has adjacent 2 similar pixel X and Y on the sheet level ground, pixel Y is arranged in shade, DN (y) and DN (x), DN _aBe respectively its remote sensing value and atmospheric path radiation radiance remote sensing value, then should locate diffusing, direct solar radiation ratio on the level ground:

L＝(DN(y)-DN _a)/(DN(x)-DN(y)) (6)

Each point ground direct light influence of topography coefficient is calculated as follows on the calculating satellite remote sensing digital image in the above-mentioned step (6):

F _ij＝1-tgα _ij·ctgθ _ij·cosω _ij，ω _ij＝AL _ij-A _ij (7)

Wherein, α _IjRepresent pixel face of land slope angle, AL _IjRepresent face of land aspect, θ _IjSubstar sun altitude in the sheet annotation, A are defended in representative _IjRepresent solar azimuth, ω _IjRepresent the angle of solar azimuth and ground aspect.

Each point ground sky scattering light influence of topography coefficient on the calculating satellite remote sensing digital image in the above-mentioned step (7), the ratio of promptly defending sky scattering rayed solid angle 2 π on sheet pixel ground sky scattering rayed solid angle and the level ground is calculated as follows:

$G_{\mathrm{ij}}=1-\frac{2}{\mathrm{n\π}}\underset{k=1}{\overset{n}{\mathrm{\Σ}}}{\mathrm{\β}}_k,$ N=2 π in the formula/Δ t (8)

Wherein, β _kBe that maximum average shield angle on K the orientation is a solid angle.Δ t is the position angle step-length, is 360 °/n.N is the orientation number of partitions, and promptly n is by the scope number of computational accuracy requirement with 360 ° of divisions.

Parsing satellite remote sensing images in the above-mentioned step (8); Generate direct sunlight remote sensing images and sky scattering light remote sensing images, method is as follows:

Direct sunlight remote sensing images expression formula: ${\mathrm{DN}}_{\mathrm{Sij}}=\frac{({\mathrm{DN}}_{\mathrm{ij}}-{\mathrm{DN}}_{\mathrm{Aij}})\·F_{\mathrm{ij}}}{(F_{\mathrm{ij}}+G_{\mathrm{ij}}\·L_{\mathrm{ij}})}---\left(9\right)$

Sky scattering light remote sensing images expression formula: ${\mathrm{DN}}_{\mathrm{Dij}}=\frac{({\mathrm{DN}}_{\mathrm{ij}}-{\mathrm{DN}}_{\mathrm{Aij}})\·G_{\mathrm{ij}}\·L_{\mathrm{ij}}}{F_{\mathrm{ij}}+G_{\mathrm{ij}}\·L_{\mathrm{ij}}}---\left(10\right)$

i＝1，2…m；j＝1，2…n

Wherein, DN _SijRepresent direct light component in the element remote sensing numerical value, DN _IjRepresent element remote sensing numerical value, DN _AijRepresent the atmospheric path radiance remote sensing value, L _IjRepresent ground return brightness, F _IjRepresent direct light influence of topography coefficient in each point ground on the digital topography map, G _IjRepresent each point ground sky scattering light influence of topography coefficient on the digital topography map, DN _DijRepresent scattered light component in the element remote sensing numerical value, L _SijRepresent ground spectrum reflecting brightness, L _DijRepresent terrestrial radiation illumination.

The topographic change of direct sunlight remote sensing digital image in the above-mentioned step (9) and sky scattering light remote sensing digital image, adopt following formula to calculate:

${{\mathrm{DN}}^{\′}}_{S_{\mathrm{ij}}}={\mathrm{DN}}_{S_{\mathrm{ij}}}/F_{\mathrm{ij}}=({\mathrm{DN}}_{\mathrm{ij}}-{\mathrm{DN}}_{\mathrm{Aij}})/(F_{\mathrm{ij}}+G_{\mathrm{ij}}\·L_{\mathrm{ij}})---\left(11\right)$

${{\mathrm{DN}}^{\′}}_{\mathrm{Dij}}={\mathrm{DN}}_{\mathrm{Dij}}/G_{\mathrm{ij}}=({\mathrm{DN}}_{\mathrm{ij}}-{\mathrm{DN}}_{\mathrm{Aij}})\·L_{\mathrm{ij}}/(F_{\mathrm{ij}}+G_{\mathrm{ij}}\·L_{\mathrm{ij}})---\left(12\right)$

i＝1，2…m；j＝1，2…n

Wherein, DN _IjRepresent element remote sensing numerical value, DN _IjThe satellite element remote sensing data of ' representative after Atmospheric corrections, DN _SijDirect light component in the satellite element remote sensing data of ' representative after Atmospheric corrections, DN _DijScattered light component in the satellite element remote sensing data of ' representative after Atmospheric corrections, DN _DijRepresent scattered light component in the element remote sensing numerical value, DN _SijRepresent direct light component in the element remote sensing numerical value, DN _AijRepresent the atmospheric path radiance remote sensing value.

The elimination of massif and clouds layer shadow on the satellite remote sensing digital image in the above-mentioned step (10), adopt the shade pixel on the satellite remote sensing digital image to carry out following digital operation:

${{\mathrm{DN}}^{\′}}_{\mathrm{ij}}=({\mathrm{DN}}_{\mathrm{ij}}-{\mathrm{DN}}_{\mathrm{Aij}})\·(1+L_{\mathrm{ij}})/(F_{\mathrm{ij}}+G_{\mathrm{ij}}\·L_{\mathrm{ij}})---\left(13\right)$

Wherein, DN _IjRepresent element remote sensing numerical value, DN _IjThe satellite element remote sensing data of ' representative after Atmospheric corrections, DN _AijRepresent the atmospheric path radiance remote sensing value.

The computing machine of the satellite remote sensing digital image shadow-free orthography in the above-mentioned step (11) generates, and uses following digital operation to finish:

${{\mathrm{DN}}_{\mathrm{ij}}}^{\′}={\mathrm{DN}}_{\mathrm{Sij}}^{\′}+{\mathrm{DN}}_{\mathrm{Dij}}^{\′}---\left(14\right)$

${{\mathrm{DN}}^{\′}}_{\mathrm{ij}}=({\mathrm{DN}}_{\mathrm{ij}}-{\mathrm{DN}}_{\mathrm{Aij}})\·(1+L_{\mathrm{ij}})/(F_{\mathrm{ij}}+G_{\mathrm{ij}}\·L_{\mathrm{ij}})---\left(15\right)$

Wherein, DN _IjRepresent element remote sensing numerical value, DN _IjThe satellite element remote sensing data of ' representative after Atmospheric corrections, DN _SijDirect light component in the satellite element remote sensing data of ' representative after Atmospheric corrections, DN _DijScattered light component in the satellite element remote sensing data of ' representative after Atmospheric corrections, DN _DijRepresent scattered light component in the element remote sensing numerical value, DN _SijRepresent direct light component in the element remote sensing numerical value, DN _AijRepresent the atmospheric path radiance remote sensing value.

Above-mentioned pixel atmospheric path radiation radiation DN _Aij, draw by extraction or ground observation data computation in the relevant information in the digital picture; Above-mentioned pixel ground altitude of the sun θ _Ij, position angle AL _IjDraw by defending the associated information calculation that the sheet annotation provides; Above-mentioned pixel ground inclination α _Ij, aspect A _IjAnd pixel provides by defending the corresponding DTM of sheet through, latitude.The fractal transform at random of the satellite remote sensing digital image under the GIS in the above-mentioned step (12) supports, use following digital operation to finish:

XDN _sij＝DN` <sub>sij</sub>×F` _ij＝DN _sij×F` <sub>ij</sub>/F <sub>ij</sub>＝(DN <sub>ij</sub>-D <sub>Aij</sub>)×F` _ij/(F _ij+L _ijG _ij) (16)

Wherein:

Virtual domatic pixel direct sunlight horizontal transformation coefficient F _Ij'=(1-tg α _Ij' ctg θ _Ij' cos ω _Ij') utilize formula

XDN _sij＝DN` <sub>sij</sub>×F` _ij＝DN _sij×F` <sub>ij</sub>/F <sub>ij</sub>＝(DN <sub>ij</sub>-D <sub>Aij</sub>)×F` _ij/(F _ij+L _ijG _ij)i＝1，2…m；j＝1，2…n (17)

Virtual and the emulation that just can finish direct sunlight remote sensing digital image landform and radiation is calculated in pointwise.

Wherein, XDN _SijRepresent direct light component in the element remote sensing numerical value, DN _SijDirect light component in the satellite element remote sensing data of ' representative after Atmospheric corrections, F _IjRepresent direct light influence of topography coefficient in each point ground on the digital topography map, F _Ij' representative direct light influence of topography coefficient in each point ground on the digital topography map after the Atmospheric corrections, DN _IjRepresent element remote sensing numerical value, DN _AijRepresent the atmospheric path radiance remote sensing value, L _IjRepresent ground return brightness, G _IjRepresent each point ground sky scattering light influence of topography coefficient on the digital topography map, α _IjThe revised pixel of ' representative face of land slope angle, θ _IjRevised substar sun altitude in the sheet annotation, the ω of defending of ' representative _IjThe angle of revised solar azimuth of ' representative and ground aspect.

The present invention compared with prior art has following conspicuous outstanding substantive distinguishing features and remarkable advantage:

Because the satellite remote sensing imaging is under the natural light condition, the natural light composition comprises direct sunlight (directivity) component and sky scattering light (being isotropy basically), its relative intensity and the reallocation mode on relief surface have very big-difference to the influence of satellite remote sensing date.Satellite remote sensing images after the Atmospheric corrections is resolved, be separated into direct sunlight remote sensing images and sky scattering light remote sensing images, carry out the conversion of direct sunlight and sky scattering light respectively, form the corresponding direct sunlight and the topographic change remote sensing digital image of sky scattering light, at last with the topographic change satellite remote sensing digital image under the two synthetic natural light condition.Its theory, the more traditional process in remote sensing digital image processing of method (natural light is whole) advanced person, science, reasonable.Simultaneously, generated: direct sunlight and sky scattering light remote sensing digital image and their topographic change digital picture all are that nature can't directly obtain, and in theory with in the practice sensor information of important value are arranged all.

Because the topographic change of remote sensing digital image has been eliminated the face of land optical radiation difference that topographic relief brings and the influence of cloud layer and massif shade, has given prominence to the ground-object spectrum feature in sensor information, makes it have more comparability.The quality of fundamentally having improved remote sensing digital image has important scientific research and application prospect.

This invention can be widely used in the variable research and various application of remote sensing technology, studies, defends the pattern-recognition of sheet and the aspects such as virtual and emulation of remote sensing digital image as land-use study and camouflage and counter camouflage, the identification of shade atural object, forest survey in investigation, the military affairs.

Description of drawings

Fig. 1 is the topographic change computing machine product process figure of the satellite remote sensing digital image under the GIS support of the present invention.

Fig. 2 is that area, Longyan, Fujian 1998.12.8 is through the TM remote sensing digital image (1024 * 1024) after the Atmospheric corrections;

Fig. 3 is for to defend the corresponding digital topography map of sheet (solid) with this;

Fig. 4,5 are respectively direct sunlight and the sky scattering light topographic correction coefficient and the visual image thereof of each point on the satellite remote sensing digital image;

Fig. 6,7 are respectively this defends direct sunlight and the sky scattering light remote sensing digital image that sheet is resolved the back generation;

Fig. 8,9 are respectively Fig. 5,6 the image of fractal transform flatly;

Figure 10 is just penetrating digital picture for the shadow-free remote sensing of Fig. 2;

Figure 11 is Fig. 2 remote sensing digital image behind the fractal transform at random.

Embodiment

A preferred embodiment of the present invention is described with reference to the accompanying drawings as follows: this example is the topographic change of defending the satellite remote sensing digital image of sheet under supporting with GIS of Longyan, Fujian area 1998.12.8.Referring to Fig. 1, the topographic change method of the satellite remote sensing digital image under this GIS supports is:

At first, set up the mathematical model of quantitative relationship between satellite remote sensing information and landform, direct sunlight and the sky scattering light; The parsing satellite remote sensing digital image that continues: generate direct sunlight remote sensing images and sky scattering light remote sensing images, carry out topographic change respectively, the radiation difference on the elimination rugged topography and this species diversity are to the influence of satellite remote sensing digital image; Judge and eliminate the massif and the clouds layer shadow of remote sensing digital image then; Finish the topographic change of satellite remote sensing digital image on this basis at last.Theory of the present invention, the more traditional remote sensing digital processing of method advanced person, science, reasonable can be widely used in the quantitative examination and the application of remote sensing technology; Its concrete operations step is as follows:

(1), satellite remote sensing digital image and digital topography map registration;

(2), the Atmospheric corrections of satellite remote sensing digital image;

(3), each point sun altitude, azimuthal calculating on the satellite remote sensing digital image;

(4), calculate each point ground (domatic) direct sunlight topographic correction coefficient and ground (domatic) sky scattering light topographic correction coefficient on the satellite remote sensing digital image on the digital topography map:

(5), observe the scattering on the each point level ground/radiation ratio on measurement or the calculating satellite remote sensing digital image:

(6), resolve satellite remote sensing images; Generate direct sunlight remote sensing images and sky scattering light remote sensing images;

(7), the elimination of massif and clouds layer shadow on the judgement of massif and clouds layer shadow and the satellite remote sensing digital image on the satellite remote sensing digital image;

(8), the fractal transform flatly of direct sunlight remote sensing images and sky scattering light remote sensing images;

(9), the computing machine generation of digital picture is just being penetrated in shadow-free remote sensing;

(10), the fractal transform at random of remote sensing images.

The topographic change of satellite remote sensing digital image is having the topographic change effect that the best is arranged under the conditions such as the real-time radiation observational data of multiple spot (scattering/radiation ratio), the Atmospheric corrections of satellite remote sensing digital image high precision, typical feature reflectivity and corresponding high-precision digital topography map.If above-mentioned condition can not satisfy, only utilize the digital topography map of general precision to carry out the satellite remote sensing digital image topographic change and also can obtain gratifying better effects.Each step is described as follows in the such scheme:

1, satellite remote sensing digital image and digital topography map registration:

Satellite remote sensing digital image and digital topography map (TEM) registration is the GIS routine operation.

2, the Atmospheric corrections of star remote sensing digital image: the method that obtains pixel atmospheric path radiance remote sensing value has two kinds:

Ground surface reflectance γ 1 and γ 2 that adjacent two non-similar pixel DN1 and DN2 on the identical ground of sheet are defended in utilization enter following calculating: DN (a)=γ 1* (DN1-DN2)/(γ 1-γ 2) (1)

Can obtain the pixel atmospheric path radiance remote sensing value of Discrete Distribution.

Water body element remote sensing value in massif on the satellite remote sensing digital image and the clouds layer shadow is analyzed the pixel atmospheric path radiance remote sensing value that also can obtain Discrete Distribution.

To The above results, adopt interpolation algorithm can obtain each pixel atmospheric path radiance remote sensing value again.Each pixel point remote sensing value on the satellite remote sensing digital image is deducted the computing of atmospheric path radiance remote sensing value, i.e. DN _Ij-DN _Aij, just finished the Atmospheric corrections of satellite remote sensing digital image.

Wherein, DN _IjRepresent each pixel point remote sensing value on the satellite remote sensing digital image, DN _AijRepresent the atmospheric path radiance remote sensing value, DN _Ij-DN _AijRepresent the Atmospheric corrections value of satellite remote sensing digital image.

3, each point sun altitude, azimuthal calculating are calculated by following formula on the satellite remote sensing digital image:

θ _ij＝arcsin(sinφ*sinδ+cosφ*cosδ*cost(i，j)) (2)

A(i，j)＝arcsin(sinθ _ij*sinφ-sinδ)/cosθ _ij*cosφ) (3)

δ＝arcsin(sinθ*sinφ-cosθ*cosφ*cosA) (4)

t＝arcsin(cosθ _ij*sinA/cosδ)+Δλ (5)

θ, A, δ: defend substar sun altitude in the sheet annotation, position angle and sun Chi Jiao; λ, φ: be respectively the geographical longitude and latitude of substar.Δ λ is the longitude increment of pixel point to substar.

4, the judgement of massif and clouds layer shadow on the remote sensing digital image

Utilize digital topography map and the location parameter of defending the sun of sheet pixel with the satellite remote sensing digital image registration, be elevation angle, position angle, carry out the judgement of massif and clouds layer shadow, the criterion of its judgement is: the sun altitude that is equal to, or greater than this pixel point in the maximum landform, cloud layer, the elevation angle that shine upon this pixel point of direction promptly: DH (i, j) 〉=θ _Ij, then this pixel point is a shade; Otherwise then not shade.

5, straight, the scattered radiation ratio on the each point level ground on observation or the calculating satellite remote sensing digital image:

If defending has adjacent 2 similar pixel X and Y on the sheet level ground, pixel Y is arranged in shade, DN (y) and DN (x), DN _aBe respectively its remote sensing value and atmospheric path radiance remote sensing value, then should locate diffusing, direct solar radiation ratio on the level ground:

L＝(DN(y)-DN _a)/(DN(x)-DN(y)) (6)

6, calculate each point ground direct light influence of topography coefficient on the digital topography map:

F _ij＝1-tgα _ij·ctgθ _ij·cosω _ij，ω _ij＝AL _ij-A _ij (7)

Wherein, α _IjRepresent pixel face of land slope angle, AL _IjRepresent face of land aspect, θ _IjSubstar sun altitude in the sheet annotation, A are defended in representative _IjRepresent solar azimuth, ω _IjRepresent the angle of solar azimuth and ground aspect.

7, calculate each point ground sky scattering light influence of topography coefficient on the digital topography map, promptly defend the ratio of sky scattering rayed solid angle 2 π on sheet pixel ground sky scattering rayed solid angle and the level ground:

$G_{\mathrm{ij}}=1-\frac{2}{\mathrm{n\&pi;}}\underset{k=1}{\overset{n}{\mathrm{\&Sigma;}}}{\mathrm{\&beta;}}_k,$ N=2 π in the formula/Δ t (8)

Wherein, β _kBe that maximum average shield angle on K the orientation is a solid angle.Δ t is the position angle step-length, is 360 °/n.N is the orientation number of partitions, and promptly n is by the scope number of computational accuracy requirement with 360 ° of divisions.

8, resolve satellite remote sensing images, generate direct sunlight remote sensing images and sky scattering light remote sensing images, method is as follows:

Direct sunlight remote sensing images expression formula: ${\mathrm{DN}}_{\mathrm{Sij}}=\frac{({\mathrm{DN}}_{\mathrm{ij}}-{\mathrm{DN}}_{\mathrm{Aij}})\&CenterDot;F_{\mathrm{ij}}}{(F_{\mathrm{ij}}+G_{\mathrm{ij}}\&CenterDot;L_{\mathrm{ij}})}---\left(9\right)$

Sky scattering light remote sensing images expression formula: ${\mathrm{DN}}_{\mathrm{Dij}}=\frac{({\mathrm{DN}}_{\mathrm{ij}}-{\mathrm{DN}}_{\mathrm{Aij}})\&CenterDot;G_{\mathrm{ij}}\&CenterDot;L_{\mathrm{ij}}}{F_{\mathrm{ij}}+G_{\mathrm{ij}}\&CenterDot;L_{\mathrm{ij}}}---\left(10\right)$

i＝1，2…m；j＝1，2…n

Wherein, DN _SijRepresent direct light component in the element remote sensing numerical value, DN _IjRepresent element remote sensing numerical value, DN _AijRepresent the atmospheric path radiance remote sensing value, L _IjRepresent ground return brightness, F _IjRepresent direct light influence of topography coefficient in each point ground on the digital topography map, G _IjRepresent each point ground sky scattering light influence of topography coefficient on the digital topography map, DN _DijRepresent scattered light component in the element remote sensing numerical value, L _SijRepresent ground spectrum reflecting brightness, L _DijRepresent terrestrial radiation illumination.

9, the topographic change of direct sunlight remote sensing digital image and sky scattering light remote sensing digital image, adopt following formula to calculate:

${{\mathrm{DN}}^{\&prime;}}_{S_{\mathrm{ij}}}={\mathrm{DN}}_{S_{\mathrm{ij}}}/F_{\mathrm{ij}}=({\mathrm{DN}}_{\mathrm{ij}}-{\mathrm{DN}}_{\mathrm{Aij}})/(F_{\mathrm{ij}}+G_{\mathrm{ij}}\&CenterDot;L_{\mathrm{ij}})---\left(11\right)$

${{\mathrm{DN}}^{\&prime;}}_{\mathrm{Dij}}={\mathrm{DN}}_{\mathrm{Dij}}/G_{\mathrm{ij}}=({\mathrm{DN}}_{\mathrm{ij}}-{\mathrm{DN}}_{\mathrm{Aij}})\&CenterDot;L_{\mathrm{ij}}/(F_{\mathrm{ij}}+G_{\mathrm{ij}}\&CenterDot;L_{\mathrm{ij}})---\left(12\right)$

i＝1，2…m；j＝1，2…n

Wherein, DD _IjRepresent element remote sensing numerical value, DN _IjThe satellite element remote sensing data of ' representative after Atmospheric corrections, DN _SijDirect light component in the satellite element remote sensing data of ' representative after Atmospheric corrections, DN _DijScattered light component in the satellite element remote sensing data of ' representative after Atmospheric corrections, DN _DijRepresent scattered light component in the element remote sensing numerical value, DN _SijRepresent direct light component in the element remote sensing numerical value, DN _AijRepresent the atmospheric path radiance remote sensing value.

The topographic change of the satellite remote sensing digital image under 10, GIS supports, use following digital operation to finish:

${{\mathrm{DN}}_{\mathrm{ij}}}^{\&prime;}={\mathrm{DN}}_{\mathrm{Sij}}^{\&prime;}+{\mathrm{DN}}_{\mathrm{Dij}}^{\&prime;}---\left(13\right)$

${{\mathrm{DN}}^{\&prime;}}_{\mathrm{ij}}=({\mathrm{DN}}_{\mathrm{ij}}-{\mathrm{DN}}_{\mathrm{Aij}})\&CenterDot;(1+L_{\mathrm{ij}})/(F_{\mathrm{ij}}+G_{\mathrm{ij}}\&CenterDot;L_{\mathrm{ij}})---\left(14\right)$

Wherein, DN _IjRepresent element remote sensing numerical value, DN _IjThe satellite element remote sensing data of ' representative after Atmospheric corrections, DN _SijDirect light component in the satellite element remote sensing data of ' representative after Atmospheric corrections, DN _DijScattered light component in the satellite element remote sensing data of ' representative after Atmospheric corrections, DN _DijRepresent scattered light component in the element remote sensing numerical value, DN _SijRepresent direct light component in the element remote sensing numerical value, DN _AijRepresent the atmospheric path radiance remote sensing value.

11, the elimination of massif and clouds layer shadow on the satellite remote sensing digital image, adopt the shade pixel on the satellite remote sensing digital image to carry out following digital operation:

${{\mathrm{DN}}^{\&prime;}}_{\mathrm{ij}}=({\mathrm{DN}}_{\mathrm{ij}}-{\mathrm{DN}}_{\mathrm{Aij}})\&CenterDot;(1+L_{\mathrm{ij}})/(F_{\mathrm{ij}}+G_{\mathrm{ij}}\&CenterDot;L_{\mathrm{ij}})---\left(15\right)$

Wherein, DN _IjRepresent element remote sensing numerical value, DN _IjThe satellite element remote sensing data of ' representative after Atmospheric corrections, DN _AijRepresent the atmospheric path radiance remote sensing value.

Above-mentioned pixel atmospheric path radiation radiation DN _Aij, draw by extraction or ground observation data computation in the relevant information in the digital picture; Above-mentioned pixel ground altitude of the sun θ _Ij, position angle AL _IjDraw by defending the associated information calculation that the sheet annotation provides; Above-mentioned pixel ground inclination α _Ij, aspect A _IjAnd pixel provides by defending the corresponding DTM of sheet through, latitude.

12, the fractal transform at random of satellite remote sensing digital image, use following digital operation to finish:

XDN _sij＝DN` <sub>sij</sub>×F` _ij＝DN _sij×F` <sub>ij</sub>/F <sub>ij</sub>＝(DN <sub>ij</sub>-D <sub>Aij</sub>)×F` _ij/(F _ij+L _ijG _ij) (16)

Wherein:

Virtual domatic pixel direct sunlight horizontal transformation coefficient F _Ij'=(1-tg α _Ij' ctg θ _Ij' cos ω _Ij') utilize formula

XDN _sij＝DN` <sub>sij</sub>×F` _ij＝DN _sij×F` <sub>ij</sub>/F <sub>ij</sub>＝(DN <sub>ij</sub>-D <sub>Aij</sub>)×F` _ij/(F _ij+L _ijG _ij)i＝1，2…m；j＝1，2，…，n (17)

Virtual and the emulation that just can finish direct sunlight remote sensing digital image landform and radiation is calculated in pointwise.

Wherein, XDN _SijRepresent direct light component in the element remote sensing numerical value, DN _SijDirect light component in the satellite element remote sensing data of ' representative after Atmospheric corrections, F _IjRepresent direct light influence of topography coefficient in each point ground on the digital topography map, F _Ij' representative direct light influence of topography coefficient in each point ground on the digital topography map after the Atmospheric corrections, DN _IjRepresent element remote sensing numerical value, DN _AijRepresent the atmospheric path radiance remote sensing value, L _IjRepresent ground return brightness, G _IjRepresent each point ground sky scattering light influence of topography coefficient on the digital topography map, α _IjThe revised pixel of ' representative face of land slope angle, θ _IjRevised substar sun altitude in the sheet annotation, the ω of defending of ' representative _IjThe angle of revised solar azimuth of ' representative and ground aspect.

The topographic change of satellite remote sensing digital image is having the topographic change effect that the best is arranged under the conditions such as the real-time radiation observational data of multiple spot (scattering/radiation ratio), the Atmospheric corrections of satellite remote sensing digital image high precision, typical feature reflectivity and corresponding high-precision digital topography map.If above-mentioned condition can not satisfy, only utilize the digital topography map of general precision to carry out the satellite remote sensing digital image topographic change and also can obtain gratifying better effects.

Because the satellite remote sensing imaging is under the natural light condition, the natural light composition comprises direct sunlight (directivity) component and sky scattering light (being isotropy basically), its relative intensity and the reallocation mode on relief surface have very big-difference to the influence of satellite remote sensing date.Satellite remote sensing images after the Atmospheric corrections is resolved, be separated into direct sunlight remote sensing images and sky scattering light remote sensing images, carry out the conversion of direct sunlight and sky scattering light respectively, form the corresponding direct sunlight and the topographic change remote sensing digital image of sky scattering light, at last with the topographic change satellite remote sensing digital image under the two synthetic natural light condition.Its theory, the more traditional process in remote sensing digital image processing of method (natural light is whole) advanced person, science, reasonable.Simultaneously, generated: direct sunlight and sky scattering light remote sensing digital image and their topographic change digital picture all are that nature can't directly obtain, and in theory with in the practice sensor information of important value are arranged all.

The topographic change of remote sensing digital image has been eliminated the face of land optical radiation difference that topographic relief brings and the influence of cloud layer and massif shade, has given prominence to the ground-object spectrum feature in sensor information, makes it have more comparability.The quality of fundamentally having improved remote sensing digital image has important scientific research and application prospect.

Fig. 2 is that area, Longyan, Fujian 1998.12.8 is through the TM remote sensing digital image (1024 * 1024) after the Atmospheric corrections;

Fig. 3 is for defending the corresponding digital topography map (solid) of sheet coupling with this;

Fig. 4, Fig. 5 are respectively this and defend direct sunlight and the sky scattering light remote sensing digital image that sheet is resolved the back generation:

Tangible shade distributes direct sunlight remote sensing digital image (Fig. 4), the direct light radiation of ridge both sides has notable difference in order to have on the remote sensing digital image under the direct sunlight of the influence of topography;

Sky scattering light remote sensing digital image (Fig. 5) is the remote sensing digital image under the low-light (level) sky scattering light of the influence of topography.

Fig. 6, Fig. 7 be landform direct light topographic change coefficient and sky scattering light topographic change coefficient visual respectively, and they have very clearly physics and ground learn meaning:

Fig. 6: be the linear stretch of landform direct light topographic change coefficient.Being expressed as picture moment direct sunlight radiation distributes in the true normalization on the rolling ground (the direct sunlight radiant illumination is 1 on the level ground).

Fig. 7: be the linear stretch of sky scattering light topographic change coefficient.Being expressed as the true normalization (level ground Heaven space scattered light radiant illumination be 1) of picture moment sky scattering optical radiation on rolling ground distributes.

Direct light topographic change coefficient and sky scattering light topographic change coefficient and visually dye and aspect such as digital visual is widely used in that digital sand table, map are dizzy.

Fig. 8, Fig. 9 are respectively the image of direct sunlight and the pairing fractal transform flatly of sky scattering light remote sensing digital image:

Topographic change image (Fig. 8) top shadow of direct sunlight (nonpolarized light) remote sensing digital image is eliminated, and the water body that is hidden in originally in the shade is high-visible, and ridge both sides direct light radiation difference is not obvious, and the fluctuating mountain region has become the Plain.The topographic change image of comparing the direct sunlight remote sensing digital image with original remote sensing digital image obviously helps the automatic identification and the classification of computing machine, and its picture quality has great improving.

The topographic change image (Fig. 9) of sky scattering light remote sensing digital image is for having eliminated the remote sensing digital image of the influence of topography in each imaging under uniform sky scattering light (polarized light) condition.

The shadow-free satellite remote sensing digital orthoimage that Figure 10 generates for computing machine (Fig. 8 and Fig. 9's is synthetic).

Figure 11 is Fig. 2 remote sensing digital image behind the fractal transform at random.

The topographic change of satellite remote sensing digital image is having multiple spot under the conditions such as radiation observational data (scattering), the Atmospheric corrections of satellite remote sensing digital image high precision, typical feature reflectivity and corresponding high-precision digital topography map best topographic change effect to be arranged in real time synchronously.If above-mentioned condition can not satisfy, only utilize the digital topography map of general precision to carry out the satellite remote sensing digital image topographic change and also can obtain gratifying better effects.

Claims (13)

1.GIS the topographic change of the satellite remote sensing digital image under supporting is characterized in that:

At first, set up the mathematical model of quantitative relationship between satellite remote sensing information and landform, direct sunlight and the sky scattering light; The parsing satellite remote sensing digital image that continues: generate direct sunlight remote sensing images and sky scattering light remote sensing images, carry out topographic change respectively, the radiation difference on the elimination rugged topography and this species diversity are to the influence of satellite remote sensing digital image; Judge and eliminate the massif and the clouds layer shadow of remote sensing digital image then; Finish the topographic change of satellite remote sensing digital image on this basis at last; Its concrete operations step is as follows:

(1), satellite remote sensing digital image and digital topography map registration;

(2), the Atmospheric corrections of satellite remote sensing digital image;

(3), each point sun altitude, azimuthal calculating on the satellite remote sensing digital image;

(4), calculate each point ground or domatic direct sunlight topographic correction coefficient and ground or domatic sky scattering light topographic correction coefficient on the satellite remote sensing digital image on the digital topography map;

(5), observe the scattering/radiation ratio on the each point level ground on measurement or the calculating satellite remote sensing digital image;

(6), resolve satellite remote sensing images; Generate direct sunlight remote sensing images and sky scattering light remote sensing images;

(7), the elimination of massif and clouds layer shadow on the judgement of massif and clouds layer shadow and the satellite remote sensing digital image on the satellite remote sensing digital image;

(8), the fractal transform flatly of direct sunlight remote sensing images and sky scattering light remote sensing images;

(9), the computing machine generation of digital picture is just being penetrated in shadow-free remote sensing;

(10), the fractal transform at random of remote sensing images.

The topographic change of the satellite remote sensing digital image under 2, GIS according to claim 1 supports is characterized in that the step of Atmospheric corrections of the satellite remote sensing digital image in the described step (2) is as follows:

(1) utilize ground surface reflectance γ 1 and the γ 2 defend adjacent two non-similar pixel DN1 and DN2 on the identical ground of sheet,

Be calculated as follows the pixel atmospheric path radiance remote sensing value that can obtain Discrete Distribution:

DN(a)＝γ1*(DN1-DN2)/(γ1-γ2)，

Perhaps the water body element remote sensing value in massif on the satellite remote sensing digital image and the clouds layer shadow is analyzed the pixel atmospheric path radiance remote sensing value that obtains Discrete Distribution;

(2), adopt interpolation algorithm to obtain each pixel atmospheric path radiance remote sensing value again to The above results;

(3) to each pixel point remote sensing value DN on the satellite remote sensing digital image _IjDeduct atmospheric path radiance remote sensing value DN _AijComputing, i.e. DN _Ij-DN _Aij, just finished the Atmospheric corrections of satellite remote sensing digital image,

Wherein, DN _IjRepresent each pixel point remote sensing value on the satellite remote sensing digital image, DN _AijRepresent the atmospheric path radiance remote sensing value, DN _Ij-DN _AijRepresent the Atmospheric corrections value of satellite remote sensing digital image.

The topographic change of the satellite remote sensing digital image under 3, GIS according to claim 1 supports is characterized in that each point sun altitude, azimuthal calculating are calculated by following formula on the satellite remote sensing digital image in the described step (3):

θ _ij＝arcsin(sinφ*sinδ+cosφ*cosδ*cost(i，j))，

A(i，j)＝arcsin(sinθ _ij*sinφ-sinδ)/cosθ _ij*cosφ)，

δ＝arcsin(sinθ*sinφ-cosθ*cosφ*cosA)，

t＝arcsin(cosθ _ij*sinA/cosδ)+Δλ，

θ, A, δ: defend substar sun altitude in the sheet annotation, position angle and sun Chi Jiao; λ, φ: be respectively the geographical longitude and latitude of substar.Δ λ is the longitude increment of pixel point to substar.

The topographic change of the satellite remote sensing digital image under 4, GIS according to claim 1 supports is characterized in that the determination methods of massif and clouds layer shadow is as follows on the satellite remote sensing digital image in the described step (4):

Utilize digital topography map and the location parameter of defending the sun of sheet pixel with the satellite remote sensing digital image registration, be elevation angle, position angle, carry out the judgement of massif and clouds layer shadow, the criterion of its judgement is: the sun altitude that is equal to, or greater than this pixel point in the maximum landform, cloud layer, the elevation angle that shine upon this pixel point of direction promptly: DH (i, j) 〉=θ _Ij, then this pixel point is a shade; Otherwise then not shade.

5, GIS according to claim 1 supports the topographic change of satellite remote sensing digital image down, it is characterized in that the observation in the described step (5) or calculate on the satellite remote sensing digital image on the each point level ground directly, the scattered radiation ratio method is as follows:

If defending has adjacent 2 similar pixel X and Y on the sheet level ground, pixel Y is arranged in shade, DN (y) and DN (x), DN _aBe respectively its remote sensing value and atmospheric path radiance remote sensing value, then should locate diffusing, direct solar radiation ratio on the level ground:

L＝(DN(y)-DN _a)/(DN(x)-DN(y))。

6. the topographic change of the satellite remote sensing digital image under GIS according to claim 1 supports is characterized in that each point ground direct light influence of topography coefficient is calculated as follows on the calculating digital topography map in the described step (6):

F _ij＝1-tgα _ij·ctgθ _ij·cosω _ij，ω _ij＝AL _ij-A _ij，

Wherein, α _IjRepresent pixel face of land slope angle, AL _IjRepresent face of land aspect, θ _IjSubstar sun altitude in the sheet annotation, A are defended in representative _IjRepresent solar azimuth, ω _IjRepresent the angle of solar azimuth and ground aspect.

7. the topographic change of the satellite remote sensing digital image under GIS according to claim 1 supports, it is characterized in that each point ground sky scattering light influence of topography coefficient on the calculating digital topography map in the described step (7), the ratio of promptly defending sky scattering rayed solid angle 2 π on sheet pixel ground sky scattering rayed solid angle and the level ground is calculated as follows:

$G_{\mathrm{ij}}=1-\frac{2}{\mathrm{n\&pi;}}\underset{k=1}{\overset{n}{\mathrm{\&Sigma;}}}{\mathrm{\&beta;}}_k,$ N=2 π/Δ t in the formula,

Wherein, β _kBe that maximum average shield angle on K the orientation is a solid angle, Δ t is the position angle step-length, is 360 °/n, and n is the orientation number of partitions, and promptly n is for by the scope number of computational accuracy requirement with 360 ° of divisions.

8. the topographic change of the satellite remote sensing digital image under GIS according to claim 1 supports is characterized in that the parsing satellite remote sensing images in the described step (8), generates direct sunlight remote sensing images and sky scattering light remote sensing images, and method is as follows:

Direct sunlight remote sensing images expression formula: ${\mathrm{DN}}_{\mathrm{Sij}}=\frac{({\mathrm{DN}}_{\mathrm{ij}}-{\mathrm{DN}}_{\mathrm{Aij}})\&CenterDot;F_{\mathrm{ij}}}{(F_{\mathrm{ij}}+G_{\mathrm{ij}}\&CenterDot;L_{\mathrm{ij}})},$

Sky scattering light remote sensing images expression formula: ${\mathrm{DN}}_{\mathrm{Dij}}=\frac{({\mathrm{DN}}_{\mathrm{ij}}-{\mathrm{DN}}_{\mathrm{Aij}})\&CenterDot;G_{\mathrm{ij}}\&CenterDot;L_{\mathrm{ij}}}{F_{\mathrm{ij}}+G_{\mathrm{ij}}\&CenterDot;L_{\mathrm{ij}}},$

i＝1，2…m，j＝1，2…n，

Wherein, DN _SijRepresent direct light component in the element remote sensing numerical value, DN _IjRepresent element remote sensing numerical value, DN _AijRepresent the atmospheric path radiance remote sensing value, L _IjRepresent ground return brightness, F _IjRepresent direct light influence of topography coefficient in each point ground on the digital topography map, G _IjRepresent each point ground sky scattering light influence of topography coefficient on the digital topography map, DN _DijRepresent scattered light component in the element remote sensing numerical value, L _SijRepresent ground spectrum reflecting brightness, L _DijRepresent terrestrial radiation illumination.

9. the topographic change of the satellite remote sensing digital image under GIS according to claim 1 supports, it is characterized in that the direct sunlight remote sensing digital image in the described step (9) and the topographic change of sky scattering light remote sensing digital image, adopt following formula to calculate:

DN′ _Sij＝DN _Sij/F _ij＝(DN _ij-DN _Aij)/(F _ij+G _ij·L _ij)，

DN′ _Dij＝DN _Dij/G _ij＝(DN _ij-DN _Aij)·L _ij/(F _ij+G _ij·L _ij)，

i＝1，2…m，j＝1，2…n，

Wherein, DN _IjRepresent element remote sensing numerical value, DN ' _IjThe satellite element remote sensing data of representative after Atmospheric corrections, DN ' _SijDirect light component in the satellite element remote sensing data of representative after Atmospheric corrections, DN ' _DijScattered light component in the satellite element remote sensing data of representative after Atmospheric corrections, DN _DijRepresent scattered light component in the element remote sensing numerical value, DN _SijRepresent direct light component in the element remote sensing numerical value, DN _AijRepresent the atmospheric path radiance remote sensing value.

10. GIS according to claim 1 supports the topographic change of satellite remote sensing digital image down, it is characterized in that the topographic change of the satellite remote sensing digital image under the GIS support in the described step (10), uses following digital operation to finish:

DN′ _ij＝DN′ _Sij+DN′ _Dij，

DN′ _ij＝(DN _ij-DN _Aij)·(1+L _ij)/(F _ij+G _ij·L _ij)，

Wherein, DN _IjRepresent element remote sensing numerical value, DN ' _IjThe satellite element remote sensing data of representative after Atmospheric corrections, DN ' _SijDirect light component in the satellite element remote sensing data of representative after Atmospheric corrections, DN ' _DijScattered light component in the satellite element remote sensing data of representative after Atmospheric corrections, DN _DijRepresent scattered light component in the element remote sensing numerical value, DN _SijRepresent direct light component in the element remote sensing numerical value, DN _AijRepresent the atmospheric path radiance remote sensing value.

The topographic change of the satellite remote sensing digital image under 11. GIS according to claim 1 supports, it is characterized in that the elimination of massif and clouds layer shadow on the satellite remote sensing digital image in the described step (11), adopt the shade pixel on the satellite remote sensing digital image to carry out following digital operation:

DN′ _ij＝(DN _ij-DN _Aij)·(1+L _ij)/(F _ij+G _ij·L _ij)，

Wherein, DN _IjRepresent element remote sensing numerical value, DN ' _IjThe satellite element remote sensing data of representative after Atmospheric corrections, DN _AijRepresent the atmospheric path radiance remote sensing value.

12. the topographic change according to the satellite remote sensing digital image under claim 2 or the 3 or 6 described GIS supports is characterized in that described pixel atmospheric path radiation radiation DN _Aij, draw by extraction or ground observation data computation in the relevant information in the digital picture; Described pixel ground altitude of the sun θ _Ij, position angle AL _IjDraw by defending the associated information calculation that the sheet annotation provides; Described pixel ground inclination α _Ij, aspect A _IjAnd pixel provides by defending the corresponding DTM of sheet through, latitude.

13. the topographic change of the satellite remote sensing digital image under GIS according to claim 1 supports is characterized in that the fractal transform at random of the satellite remote sensing digital image in the described step (12) using following digital operation to finish:

XDN _sij＝DN` <sub>sij</sub>×F` _ij＝DN _sij×F` <sub>ij</sub>/F <sub>ij</sub>＝(DN <sub>ij</sub>-DN <sub>Aij</sub>)×F` _ij/(F _ij+L _ijG _ij)，

Wherein:

Virtual domatic pixel direct sunlight horizontal transformation coefficient F ' _Ij=(1-tg α ' _IjCtg θ ' _IjCos ω ' _Ij) utilize formula XDN _Sij=DN` <sub>Sij</sub>* F` _Ij=DN _Sij* F` <sub>Ij</sub>/ F <sub>Ij</sub>=(DN <sub>Ij</sub>-DN <sub>Aij</sub>) * F` _Ij/ (F _Ij+ L _IjG _Ij) i=1,2 ..., m; J=1,2 ..., n

Virtual and the emulation that just can finish direct sunlight remote sensing digital image landform and radiation is calculated in pointwise, wherein, and XDN _SijRepresent direct light component in the element remote sensing numerical value, DN ' _SijDirect light component in the satellite element remote sensing data of representative after Atmospheric corrections, F _IjRepresent direct light influence of topography coefficient in each point ground on the digital topography map, F ' _IjRepresentative is each point ground direct light influence of topography coefficient on the digital topography map after the Atmospheric corrections, DN _IjRepresent element remote sensing numerical value, DN _AijRepresent the atmospheric path radiance remote sensing value, L _IjRepresent ground return brightness, G _IjRepresent each point ground sky scattering light influence of topography coefficient on the digital topography map, α ' _IjRepresent revised pixel face of land slope angle, θ ' _IjRepresent revised substar sun altitude in the sheet annotation, the ω ' of defending _IjRepresent the angle of revised solar azimuth and ground aspect.

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