CN100480730C - Seam eliminating method for mosaic of remote sensing image - Google Patents

Abstract

This invention relates to a seam eliminating method for mosaic of remote sensing image. The Elimination Method for Jointing in Remote Sensing Image Inlay --1. deciding the overlap area for embedding according to image geodetic coordinate; 2. computing the pixel difference; 3 determining the width or height and overlap area in overlap area and the boundary coordinate, taking smoothness process; 4. taking weighted mean process, and summating the result with opposite target pixel value. This invention reduces algorithm complexity, and improves practicability.

Description

Method of seam-line elimination during a kind of remote sensing image is inlayed

Technical field:

The invention belongs to remote sensing image embedding technique field, relate to a kind of method of seam-line elimination of the difference based on adjacent image overlap area brightness value.

Background technology:

It is one of important content of remote sensing technology application that remote sensing image is inlayed, and particularly in a big way satellite remote sensing and regional airborne remote sensing, often needs several images to inlay; Because even the very trickle gray scale difference on splicing seams place two width of cloth images all can cause tangible splicing seams, in the imaging process of reality, being spliced near image nuance of gray scale (or color) splicing boundary almost is difficult to avoid, the subtle change of ground environment, the difference of imaging angle all may cause the difference on this gray scale (or color), this species diversity has caused splicing seams very outstanding, both be unfavorable for eye-observation, also influenced effect to the analysis and the identification of atural object image and specialized information, therefore, in the image mosaic process, need a kind of technology to revise and inlay the gray scale (color) of image at the splicing seams place.

At present main method of seam-line elimination has: based on wavelet transformation, based on superimposed image and force the method for seam-line elimination that corrects; The theoretical tight still realization difficulty of small wave converting method, and can't handle coloured image; Based on the method algorithm of superimposed image simple but for the accuracy requirement of geometric tessellation in a pixel, otherwise can't reach desirable effect; The pressure correcting method that splicing seams is eliminated is difficult for determining forcing the width that corrects and can causes the variation of atural object attribute when the atural object difference of splicing seams both sides is very big.

Summary of the invention:

The object of the present invention is to provide simple, the method for seam-line elimination in realizing being easy to inlaying of a kind of algorithm based on the remote sensing image of the difference of adjacent image overlap area brightness value.

Technical scheme provided by the invention is: the method for seam-line elimination during remote sensing image is inlayed may further comprise the steps

One, determines overlapping region on their each self imagings according to the terrestrial coordinate of two width of cloth images that are used to inlay;

Two, the width of cloth in optional two width of cloth images is as reference images, and another width of cloth is as pending image;

Three, extract the brightness value of the pixel in the overlapping region on two width of cloth images respectively, (x, y), pending image overlap area pixel brightness value is f to obtain reference images overlapping region pixel brightness value g ₁(x, y);

Four, try to achieve the luminance difference V between the corresponding pixel points on two width of cloth image overlap areas (x, y)=g (x, y)-f ₁(x, y);

Five, determine the width of overlapping region or the origin coordinates X of height Sum and overlapping region by the edge fit direction;

Six, (x y) is weighted average treatment, and the result that obtains and the added luminance of pending image respective pixel are eliminated splicing seams to luminance difference V according to Sum and X.

Expression formula g (x, y), f ₁(x, y), V (x, y) in:

X is the abscissa value of pixel; Y is the ordinate value of pixel.

When two width of cloth images to the integral color obvious difference carry out splicing seams elimination processing, before above-mentioned steps one, can carry out the integral color adjustment to two width of cloth images earlier.The tone adjustment can be adopted the mean variance method of method as mentioning in " remote sensing images are used and handled and analyze " (publishing house of Tsing-Hua University, 2004) book of prior art; The present invention recommends to use the following tone based on image overlap area to adjust method:

A. obtain the brightness value of reference images and pending image overlap part from reference images; Treatment step is as follows:

The terrestrial coordinate of I, benchmark image and pending image determines with pending image overlapping areas is arranged in the reference images;

II, take out in the reference images by the brightness value g of the pixel in steps A, the resulting zone of I (x, y);

B. add up the difference distribution situation of the brightness value that pending brightness value of image and steps A obtain on the overlapping region, the statistics histogram is made smoothing processing, obtain the difference diff of histogram peak-peak place correspondence; Treatment step is as follows:

The terrestrial coordinate of I, benchmark image and pending image is determined pending image and reference images overlapping areas;

II, take out in the pending image by the brightness value f of the pixel in the resulting zone of step B, I (x, y);

III, statistics luminance difference g (x, y)-f (x, histogram distribution situation S[i y)];

IV, level and smooth luminance difference histogram S[i]:

S[min]＝(S[min]+S[min+1])/2

S[n]＝(S[n-1]+S[n]+S[n+1])/3

S[max]＝(S[max]+S[max-1])/2

Wherein, min is the minimum brightness difference, and max is a maximum luminance difference, and n gets the value between min and the max, i.e. min＜n＜max;

V, record S[i] luminance difference diff when maximum;

C. add up brightness value difference on the pending image overlap area and equal the distribution situation of the pixel brightness value of diff, the statistics histogram is made smoothing processing, obtain the brightness value Pos of histogram peak-peak place correspondence; Treatment step is as follows:

Work as in the overlapping region on I, the pending image of statistics luminance difference g (x, y)-f (x, y)=f during diff (x, brightness histogram distribution situation F[j y)];

II, with the used method of step B, IV to histogram F[j] carry out smoothing processing, and the level and smooth back of record F[j] brightness value Pos when maximum;

D. with pending image T (x, y) do adjustment on the integral color:

T (x, y)＜during Pos: T (x, y)=T (x, y) * (Pos+diff)/Pos;

T (x, y)〉during Pos: T (x, y)=[T (x, y)-Pos] * [255-(Pos+diff)]/(255-Pos)+(Pos+diff);

In the formula:

X is the abscissa value of pixel in the image, value is 1,2,3 ..., m; The m number of pixels on the horizontal direction of image for this reason wherein;

Y is the ordinate value of pixel in the image, value is 1,2,3 ..., n; The n number of pixels on the vertical direction of image for this reason wherein;

T (x, y) for this reason in the image position at (x, y) brightness value of the pixel on.

When processed image is chromatic image, before above-mentioned steps one, (adjust for adopting tone, before tone is adjusted) can carry out following processing earlier: according to the conversion method of the RGB color space, the rgb value of reference images and pending each pixel of image is converted to the HSI value to the HIS double cone model color space; The I component value of the HIS that obtains after the HIS conversion through RGB that proposes each pixel is as brightness value.

The present invention operates inlaying remote sensing image, can eliminate the splicing seams between the adjacent image.The present invention is weighted average treatment to each pixel intensity difference of adjacent image overlap area and eliminates splicing seams, has reduced the complexity of algorithm, and algorithm is simple, realization is easy, has improved practicality.

Description of drawings:

Accompanying drawing is a schematic flow sheet of the present invention.

Embodiment:

Referring to accompanying drawing, the present invention includes following steps:

One, RGB-HIS conversion

According to colorimetry knowledge as can be known, human eye is comparatively responsive to brightness sensation, simultaneously, because the difference on the remote sensing image tone mainly is to cause because of uneven illumination, difference on the form and aspect is also not obvious, all images is handled to the HIS chrominance space by the RGB color space conversion for this reason; Its formula is:

$\mathrm{\θ}=\arccos \left\{\frac{\frac{1}{2}[(R-G)+(R-B)]}{{[{(R-G)}^2+(R-B)(G-B)]}^{1/2}}\right\}$

$S=1-\frac{3}{(R+G+B)}\left[\min (R,G,B)\right]$

$I=\frac{1}{3}(R+B+G)$

In the formula:

R is the red color component value of each pixel of chromatic image;

G is the green component values of each pixel of chromatic image;

B is the blue component value of each pixel of chromatic image

Two, obtain the image overlap area brightness value

I, according to the coordinate information of pending image, take out reference images and neutralize that it has the zone of lap;

II, the brightness value of the pixel in reference images and the pending image overlap area is taken out;

Three, integral color adjustment

I, set up one with the two-dimensional matrix B of the identical size of pending image (x, y), with in the matrix corresponding to the part mark of pending image overlap area;

II, at mark image overlap area in, current brightness value of image be expressed as f (x, y), the brightness value that obtains in the step 2 can be expressed as g (x, y);

Luminance difference g in III, the statistics overlapping region (x, y)-f (x, histogram distribution situation S[i y)], S[i] can obtain by the pixel in the overlapping region is traveled through:

S[i]＝S[i]+1 (i＝g(x，y)-f(x，y))

In the formula: x, y are the ranks number of overlapping area pixel point

IV, level and smooth luminance difference histogram S[i]:

S[min]＝(S[min]+S[min+1])/2

S[n]＝(S[n-1]+S[n]+S[n+1])/3

S[max]＝(S[max]+S[max-1])/2

Wherein, min is the minimum brightness difference, and max is a maximum luminance difference, and n gets the value between min and the max, i.e. min＜n＜max;

V, record S[i] luminance difference diff when maximum;

Work as in the overlapping region on VI, the pending image of statistics luminance difference g (x, y)-f (x, y)=f during diff (x, brightness histogram distribution situation F[j y)];

VII, with used same procedure of IV step to histogram F[j] carry out smoothing processing, and the level and smooth back of record F[j] brightness value Pos when maximum;

VIII, with pending image T (x, y) do adjustment on the integral color:

T (x, y)＜during Pos: T (x, y)=T (x, y) * (Pos+diff)/Pos;

T (x, y)〉during Pos: T (x, y)=[T (x, y)-Pos] * [255-(Pos+diff)]/(255-Pos)+(Pos+diff);

X is the abscissa value of pixel in the image, value is 1,2,3 ..., m; The m number of pixels on the horizontal direction of image for this reason wherein;

Y is the ordinate value of pixel in the image, value is 1,2,3 ..., n; The n number of pixels on the vertical direction of image for this reason wherein;

T (x, y) for this reason in the image position at (x, y) brightness value of the pixel on;

Four, splicing seams is eliminated

Brightness value on I, the pending image overlap area after step 3 is handled is f ₁(x, y), the brightness value of reference images overlapping region pixel be expressed as g (x, y);

II, set up a boundary rectangle,, can try to achieve two positions of width of cloth image overlap area in boundary rectangle because this two width of cloth image position in this rectangle all determines by their coordinates separately are unique according to the coordinate of current two width of cloth images; The boundary rectangle that merges this two width of cloth image according to following method:

Top＝max(Top ₁，Top ₂)

Bot＝min(Bot ₁，Bot ₂)

Rig＝max(Rig ₁，Rig ₂)

Lef＝min(Lef ₁，Lef ₂)

In the following formula: Top, Bot, Rig, Lef are respectively upper and lower, right, the left coordinates of the boundary rectangle of trying to achieve, Top ₁, Bot ₁, Rig ₁, Lef ₁Be upper and lower, right, the left coordinate of reference images, Top ₂, Bot ₂, Rig ₂, Lef ₂It is upper and lower, right, the left coordinate of pending image; For polygon, it can be decomposed into a plurality of rectangles and operate;

III, judging and the edge fit direction of two width of cloth images to have four kinds of edge fit directions, is respectively right---left side, the first from left one right side, in---down and time---; Determination methods is as follows:

A) if Bot ₁＜Top ₂＜Top ₁And Bot ₂＜Bot ₁, the edge fit direction is last---down;

B) if Bot ₁＜Bot ₂＜Top ₁And Top ₂Top ₁, the edge fit direction is down---on;

C) if Lef ₁＜Lef ₂＜Rig ₁And Rig ₂Rig ₁, the edge fit direction is a left side---the right side;

D) if Lef ₁＜Rig ₂＜Rig ₁And Lef ₂＜Lef ₁, the edge fit direction is right---a left side;

Top wherein ₁, Bot ₁, Rig ₁, Lef ₁Be upper and lower, right, the left coordinate of reference images, Top ₂, Bot ₂, Rig ₂, Lef ₂It is upper and lower, right, the left coordinate of pending image;

IV, try to achieve the luminance difference V between the corresponding pixel points on two width of cloth image overlap areas (x, y)=g (x, y)-f ₁(x, y);

V, width (by the decision of edge fit direction, laterally being width, vertically the is height) Sum that determines the overlapping region and the origin coordinates X of overlapping region;

VI, according to Sum and X to luminance difference V (x y) is weighted average treatment, and the result that obtains and the pixel value addition of pending image respective pixel are eliminated splicing seams, has four kinds of situations according to the difference of edge fit direction:

A left side---the right side:

f ₁(x，y)＝f ₁(x，y)+(Sum+X-Y)*V(x，y)/Sum

Right---a left side:

f ₁(x，y)＝f ₁(x，y)+(Y-X)*V(x，y)/Sum

On---down:

f ₁(x，y)＝f ₁(x，y)+(Sum+X-Y)*V(x，y)/Sum

Down---on:

f ₁(x，y)＝f ₁(x，y)+(Y-X)*V(x，y)/Sum

More than in four formula, the X in preceding two formula is the coordinate figure in boundary line, the left side, overlapping region, Y is the abscissa value of current pixel; X in latter two formula is the coordinate figure of overlapping region upper border line, and Y is the ordinate value of current pixel;

The present invention can repeat the operation of the 5th step when two width of cloth images have a more than edge fit direction.

Claims (5)

1, the method for seam-line elimination during a kind of remote sensing image is inlayed is characterized in that: may further comprise the steps

One, determines overlapping region on their each self imagings according to the terrestrial coordinate of two width of cloth images that are used to inlay;

Two, the width of cloth in optional two width of cloth images is as reference images, and another width of cloth is as pending image;

Three, extract the brightness value of the pixel in the overlapping region on two width of cloth images respectively, (x, y), pending image overlap area pixel brightness value is f to obtain reference images overlapping region pixel brightness value g ₁(x, y);

Four, try to achieve the luminance difference V between the corresponding pixel points on two width of cloth image overlap areas (x, y)=g (x, y)-f ₁(x, y);

Five, determine the width of overlapping region or the origin coordinates X of height Sum and overlapping region by the edge fit direction;

Six, (x y) is weighted average treatment, and the result that obtains and the added luminance of pending image respective pixel are eliminated splicing seams to luminance difference V according to Sum and X;

Expression formula g (x, y), f ₁(x, y), V (x, y) in:

X is the abscissa value of pixel;

Y is the ordinate value of pixel.

2, method according to claim 1, it is characterized in that: when processed image is chromatic image, before step 1, carry out following processing earlier: to the conversion method of the HIS double cone model color space, the rgb value of reference images and pending each pixel of image is converted to the HSI value according to the RGB color space; I component value in the HIS value of each pixel is proposed as brightness value.

3, method according to claim 1 is characterized in that: earlier two width of cloth images were carried out the integral color adjustment before step 1.

4, method according to claim 3 is characterized in that: the tone adjustment may further comprise the steps:

A. obtain the brightness value of reference images and pending image overlap part from reference images; Treatment step is as follows:

The terrestrial coordinate of I, benchmark image and pending image determines with pending image overlapping areas is arranged in the reference images;

II, take out in the reference images by the brightness value g of the pixel in steps A, the resulting zone of I (x, y);

B. add up the difference distribution situation of the brightness value that pending brightness value of image and steps A obtain on the overlapping region, the statistics histogram is made smoothing processing, obtain the difference diff of histogram peak-peak place correspondence; Treatment step is as follows:

The terrestrial coordinate of I, benchmark image and pending image is determined pending image and reference images overlapping areas;

II, take out in the pending image by the brightness value f of the pixel in the resulting zone of step B, I (x, y);

III, statistics luminance difference g (x, y)-f (x, histogram distribution situation S[i y)];

IV, level and smooth luminance difference histogram S[i]:

S[min]＝(S[min]+S[min+1])/2

S[n]＝(S[n-1]+S[n]+S[n+1])/3

S[max]＝(S[max]+S[max-1])/2

Wherein, min is the minimum brightness difference, and max is a maximum luminance difference, and n gets the value between min and the max,

Be min＜n＜max;

V, record S[i] luminance difference diff when maximum;

C. add up brightness value difference on the pending image overlap area and equal the distribution situation of the pixel brightness value of diff, the statistics histogram is made smoothing processing, obtain the brightness value Pos of histogram peak-peak place correspondence; Treatment step is as follows:

Work as in the overlapping region on I, the pending image of statistics luminance difference g (x, y)-f (x, y)=f during diff (x, brightness histogram distribution situation F[j y)];

II, with the used method of step B, IV to histogram F[j] carry out smoothing processing, and the level and smooth back of record F[j] brightness value Pos when maximum;

D. with pending image T (x, y) do adjustment on the integral color:

T (x, y)＜during Pos: T (x, y)=T (x, y) * (Pos+diff)/Pos;

T (x, y)〉during Pos: T (x, y)=[T (x, y)-Pos] * [255-(Pos+diff)]/(255-Pos)+(Pos+diff);

In the formula:

X is the abscissa value of pixel in the image, value is 1,2,3 ..., m; M image for this reason wherein

Number of pixels on the horizontal direction;

Y is the ordinate value of pixel in the image, value is 1,2,3 ..., n; The n number of pixels on the vertical direction of image for this reason wherein;

T (x, y) for this reason in the image position at (x, y) brightness value of the pixel on.

5, according to claim 3 or 4 described methods, it is characterized in that: when processed image is chromatic image, before the tone adjustment, carry out following processing earlier: to the conversion method of the HIS double cone model color space, the rgb value of reference images and pending each pixel of image is converted to the HSI value according to the RGB color space; I component value in the HIS value of each pixel is proposed as brightness value.

Images