求 软抠图法抠图修复的matlab代码,要运用到拉普拉斯抠图矩阵

发布网友 发布时间：2022-05-01 16:36

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热心网友 时间：2022-06-19 15:54

代码来自A closed form solution to Natural Image Matting
A. Levin D. Lischinski and Y. Weiss

求Matting Laplacian矩阵L代码：
function [A,A1]=getLaplacian1(I,consts,epsilon,win_size)

if (~exist('epsilon','var'))
epsilon=0.0000001;
end
if (isempty(epsilon))
epsilon=0.0000001;
end
if (~exist('win_size','var'))
win_size=1;
end
if (isempty(win_size))
win_size=1;
end

neb_size=(win_size*2+1)^2;
[h,w,c]=size(I);
n=h; m=w;
img_size=w*h;
consts=imerode(consts,ones(win_size*2+1));

indsM=reshape([1:img_size],h,w);

tlen=sum(sum(1-consts(win_size+1:end-win_size,win_size+1:end-win_size)))*(neb_size^2);

row_inds=zeros(tlen ,1);
col_inds=zeros(tlen,1);
vals=zeros(tlen,1);
len=0;
for j=1+win_size:w-win_size
for i=win_size+1:h-win_size
if (consts(i,j))
continue
end
win_inds=indsM(i-win_size:i+win_size,j-win_size:j+win_size);
win_inds=win_inds(:);
winI=I(i-win_size:i+win_size,j-win_size:j+win_size,:);
winI=reshape(winI,neb_size,c);
win_mu=mean(winI,1)';
win_var=inv(winI'*winI/neb_size-win_mu*win_mu' +epsilon/neb_size*eye(c));

winI=winI-repmat(win_mu',neb_size,1);
tvals=(1+winI*win_var*winI')/neb_size;

row_inds(1+len:neb_size^2+len)=reshape(repmat(win_inds,1,neb_size),...
neb_size^2,1);
col_inds(1+len:neb_size^2+len)=reshape(repmat(win_inds',neb_size,1),...
neb_size^2,1);
vals(1+len:neb_size^2+len)=tvals(:);
len=len+neb_size^2;
end
end

vals=vals(1:len);
row_inds=row_inds(1:len);
col_inds=col_inds(1:len);
A=sparse(row_inds,col_inds,vals,img_size,img_size);

sumA=sum(A,2);
A=spdiags(sumA(:),0,img_size,img_size)-A;

return