A kind of image-region parasitic light cancellation element and method thereof based on square coupling
Technical field
The present invention relates to a kind of image-region parasitic light cancellation element and method thereof based on square coupling, belong to field of remote sensing image processing.
Background technology
Due to the impact of parasitic light, changed the half-tone information of image, the especially impact on image local area, brings difficulty to interpretation and the application of satellite image.Be necessary the parasitic light of satellite image to analyze, eliminate, thereby guarantee the image quality of satellite optics useful load.
The work that most of parasitic light suppresses is to realize by Optical System Design.The source of research parasitic light, thus carry out the analysis of geometrical optics policy, be to eliminate the most basic method of parasitic light.When space camera is in orbit time, the parasitic light causing for design careless omission or due to complex space environment, can only eliminate by the image processing method of rear end.Formerly educate the satellite imagery data that triumphant grade is utilized particular moment, separated actual signal and parasitic light signal, generate the parasitic light template in each moment, and the image processing method by deconvolution carries out parasitic light inhibition to FY-2 radiometer visible images.But the method is only applicable to geo-stationary meteorological satellite, for middle high-resolution earth observation satellite data, cannot isolate parasitic light signal according to particular moment imaging data.
The method directly parasitic light being suppressed based on image area is at present less, and the method not suppressing for middle high-resolution earth observation satellite image area parasitic light in actual applications.For the stray light that in middle high-resolution remote sensing images, radiant correction cannot be removed, also cannot solve.
Summary of the invention
The technical matters that the present invention solves is: overcome prior art deficiency, the even atural object remote sensing images that have stray light for image interior zone, a kind of image-region parasitic light cancellation element and method thereof based on square coupling is provided, according to the statistical law of gradation of image information, grey scale change trend by entire image, find reference average and variance that image moment coupling is calculated, the column criterion of going forward side by side square matching treatment, soon average and the variance of the gray scale of each row pixel of image are adjusted into reference to average and variance, solve middle high-resolution earth observation satellite image graph image field parasitic light and eliminated problem, improve remote sensing image processing result radiation quality.
The technical scheme that the present invention solves is: a kind of image-region parasitic light cancellation element based on square coupling, comprise that image information statistical module and region parasitic light suppress module, image information statistical module comprises data preparatory unit and data analysis unit, and parasitic light suppresses module and comprises square matching unit and result output unit; Data preparatory unit reads row value R and the train value C of pending image I, and the gray-scale value of each pixel, pending image I is middle high-resolution remote sensing images, according to the gray-scale value of each row pixel of pending image I, calculate gray-scale value average and the variance of this each row pixel of pending image I, and send pending image and each row gray-scale value average thereof and variance to data analysis unit; Data analysis unit is the reference average threshold value T of setting data analytic unit first
c, first by the gray-scale value average mean of the first row pixel of pending image I
c1be assigned to the reference average mean of data analysis unit
rwith effective average and mean
use, the gray-scale value variances sigma of the first row pixel of pending image I
c1be assigned to the reference variances sigma of data analysis unit
rwith effective variance and σ
use, then ask the i row gray-scale value average of pending image I to add the reference average mean of data analysis unit
rmean value, this mean value is assigned to again to the reference average mean of data analysis unit
rif reference average is now less than or equal to reference to average threshold value T
c, by the gray-scale value average mean of the i row pixel of pending image I
ciwith gray-scale value variances sigma
cibe added to respectively data analysis unit effective average and mean
usewith effective variance and σ
usei is more than or equal to 2 positive integer, until travel through after all row of pending image, and the total how many row gray-scale value averages of record pending image I except first row and gray-scale value variance be added to effective average and with effective variance with, this columns is designated as to effective columns; Travel through effective average after all row of pending image I and mean
usewith effective variance and σ
usedivided by effective columns, obtain final reference average and final reference variance, send pending image I, final reference average and final reference variance to square matching unit; The final reference average that square matching unit sends according to data analysis unit is carried out standard square with final reference variance to pending image I and is mated calculating, obtain region parasitic light removal of images, and region parasitic light removal of images is transferred to result output unit; Result output unit converts region parasitic light removal of images to image file and exports and show.
An image-region parasitic light removing method based on square coupling, step is as follows:
(1) data preparatory unit is obtained pending image I, and obtains the row value R of pending image I and the gray-scale value of train value C and each pixel;
(2) data preparatory unit is calculated each row I of pending image I
cigradation of image value average mean
ciwith variances sigma
ci, i is positive integer and i≤C;
(3) data analysis unit is set with reference to average threshold value T
c, order is with reference to average mean
r=mean
c1, with reference to variances sigma
r=σ
c1; Make effective average and mean
use=mean
c1, effectively variance and σ
use=σ
c1; Make effective columns n=1;
(4) the pending image i row I that data analysis unit calculates in step (2)
cigrey scale pixel value average mean
ci, gray-scale value variances sigma
ci, calculate new reference average mean
ri=(mean
r+ mean
ci)/2, if fabs is (mean
ri-mean
r)≤T
c, new effective average and mean
usei=mean
use+ mean
ci, effectively variance and σ
usei=σ
use+ σ
ci, effectively columns n value increases by 1, if fabs is (mean
ri-mean
r) >T
c, choose pending image I I
c (i+1)row I
c (i+1)calculate, i is more than or equal to 2 and be less than or equal to the positive integer of C-1;
(5) data analysis unit repeating step (4), until all row traversal finishes in pending image I, obtain effective average and mean
useC, effectively variance and σ
useCwith effective columns n value, final reference average mean
rC=mean
useC/ n, final reference variances sigma
rC=σ
useC/ n;
(6) square matching unit travels through each row of pending image I, the final reference average mean obtaining in step (5)
rCwith final reference variances sigma
rC, according to standard square matching algorithm, recalculate the gray-scale value of this row image, obtain region parasitic light removal of images;
(7) the region parasitic light removal of images I' that the output of result output unit is obtained by step (6).
The present invention's advantage is compared with prior art:
(1) parasitic light at image area, space camera being caused due to design careless omission or complex space environment in orbit time suppresses, and has avoided the situation analysis in orbit of complicated space environment and camera system;
(2) in data analysis unit, travel through by column pending image column gray average, the variation of analysis image gray scale, find Gray Level Jump region, when calculating square matching parameter, do not adopt the information in this region, guarantee when image parasitic light suppresses to remove preferably stray light region.
(3) while calculating square matching parameter, with reference to average, calculate by column, keep gradation of image line direction even transition, reconstructed images, does not have Gray Level Jump phenomenon in parasitic light inhibition result images effectively.
Accompanying drawing explanation
Fig. 1 is the schematic flow sheet of the embodiment of the present invention;
Fig. 2 is apparatus structure schematic diagram of the present invention.
Embodiment
Basic ideas of the present invention are: a kind of image-region parasitic light cancellation element and method thereof based on square coupling is provided, for image interior zone, there are the even atural object remote sensing images of stray light according to the statistical law of gradation of image information, grey scale change trend by entire image, obtain reference average and variance that image moment coupling is calculated, the column criterion of going forward side by side square matching treatment, solve middle high-resolution earth observation satellite image graph image field parasitic light and eliminated problem, improved remote sensing image processing result radiation quality.
Below in conjunction with accompanying drawing, the present invention is described in further detail, as shown in Figure 2, a kind of image-region parasitic light cancellation element based on square coupling, comprise that image information statistical module and region parasitic light suppress module, image information statistical module comprises data preparatory unit and data analysis unit, and parasitic light suppresses module and comprises square matching unit and result output unit; Data preparatory unit reads row value R and the row C value of pending image I, and the gray-scale value of each pixel, pending image I is middle high-resolution remote sensing images, according to the gray-scale value of each row pixel of pending image I, calculate gray-scale value average and the variance of this each row pixel of pending image I, and send pending image and each row gray-scale value average thereof and variance to data analysis unit; Data analysis unit is the reference average threshold value T of setting data analytic unit first
c, first by the gray-scale value average mean of the first row pixel of pending image I
c1be assigned to the reference average mean of data analysis unit
rwith effective average and mean
use, the gray-scale value variances sigma of the first row pixel of pending image I
c1be assigned to the reference variances sigma of data analysis unit
rwith effective variance and σ
use, then ask the i row gray-scale value average of pending image I to add the reference average mean of data analysis unit
rmean value, this mean value is assigned to again to the reference average mean of data analysis unit
rif reference average is now less than or equal to reference to average threshold value T
c, by the gray-scale value average mean of the i row pixel of pending image I
ciwith gray-scale value variances sigma
cibe added to respectively effective average and the mean of data analysis unit
usewith effective variance and σ
usei is more than or equal to 2 positive integer, until travel through after all row of pending image, and the total how many row gray-scale value averages of record pending image I except first row and gray-scale value variance be added to effective average and with effective variance with, this columns is designated as to effective columns; Travel through effective average and mean after all row of pending image I
usewith effective variance and σ
usedivided by effective columns, obtain final reference average and final reference variance, send pending image I, final reference average and final reference variance to square matching unit; The final reference average that square matching unit sends according to data analysis unit is carried out standard square with final reference variance to pending image I and is mated calculating, obtain region parasitic light removal of images, and region parasitic light removal of images is transferred to result output unit; Result output unit converts region parasitic light removal of images to image file and exports and show.
Utilize a kind of image-region parasitic light removing method based on square coupling of above-mentioned a kind of image-region parasitic light cancellation element based on square coupling, as shown in Figure 1, pending image is the even atural object remote sensing images that image interior zone has stray light, and this method concrete steps are as follows:
(1) data preparatory unit is obtained pending image I, and obtains the row value R=2865 of pending image I and the gray-scale value of train value C=3036 and each pixel;
(2) data preparatory unit is calculated each row gradation of image value average mean of pending image I
ciwith variances sigma
ci, i is positive integer and i≤C;
(3) data analysis unit is set with reference to average threshold value T
c=5, for even remote sensing images adjacent column average, differ larger like this, represent that half-tone information has sudden change, does not meet actual conditions.General middle high-resolution remote sensing images stray light region is inner at image, so the gray-scale value of image border is influenced less, image makes with reference to average mean
r=mean
c1=338.034, with reference to variances sigma
r=σ
c1=15.248; Make effective average and mean
use=mean
c1=338.034, effectively variance and σ
use=σ
c1=15.248; Due to pending image I first row gray average and variance directly add effective average and with effective variance and, make effective columns n=1;
(4) the pending image secondary series I that data analysis unit calculates in step (2)
c2grey scale pixel value average mean
c2=337.965, gray-scale value variances sigma
c2=15.224, calculate new reference average mean
r2=(mean
r+ mean
c2)/2=338.0, if fabs is (mean
r2-mean
r)=0.334<T
c=5, the not sudden change of this row gradation of image is described, for even remote sensing images gray scale, along column direction, be generally to seamlessly transit, so this row image is not subject to the impact of parasitic light, can be used as the parameter that parasitic light suppresses, new effective average and mean
use2=mean
use+ mean
c2=338.034+337.965=675.999, effectively variance and σ
use2=σ
use+ σ
c2=15.248+15.224=30.472, n value increases by 1, if not, chooses pending image the 3rd row I
c3calculate;
(5) data analysis unit repeating step (4), until all row traversal finishes in pending image I, obtain effective average and mean
useC=944899, effectively variance and σ
useC=49788 with effective columns n=2766, final reference average mean
r=mean
useC/ n=341.612, final reference variances sigma
r=σ
useC/ n=18.0, each row image statistics that is not subject to stray light by full width obtains the parameter that square coupling needs.
(6) square matching unit travels through each row of pending image I, the final reference average mean obtaining in step (5)
rCwith final reference variances sigma
rC, according to standard square matching algorithm, recalculate the gray-scale value of this row image, obtain region parasitic light removal of images.
(7) the region parasitic light removal of images I' that the output of result output unit is obtained by step (6).
Non-elaborated part of the present invention belongs to techniques well known.