function [thetaz]=LL_angle2(img,x,y)
rc=0;thetaz=0;
while thetaz==0
    if rc~=0
       img=imrotate(img,rc);
    end
    [imgN,imgM]=size(img);
    image=zeros(imgN,imgM);
    R=width(x,y,img);
    r=10*R;
    for i=1:imgN        %行
        for j=1:imgM    %列
            if sqrt((j-x)^2+(i-y)^2)<r
                image(i,j)=~img(i,j);
            end
        end
    end
    BW=bwmorph(image,'thin',Inf);
    [H,theta,rho]= hough(BW);
    P = houghpeaks(H,7,'threshold',ceil(0.4*max(H(:))));%检测投票结果
    lines = houghlines(BW,theta,rho,P,'FillGap',5,'MinLength',7);%检测直线
    for k = 1:length(lines)
        len = norm(lines(k).point1 - lines(k).point2);%直线的长度
        a(k)=len;
        [~,t]=sort(a);
    end
    N=min(3,length(lines));thetax=zeros(1,N);

    for i=1:N
        thetax(i)=lines(t(length(t)-(i-1))).theta;
    end
    figure;subplot(121);imshow(BW);
    subplot(122);imshow(BW);
    hold on;
    for i=1:N
        xy{i}= [lines(t(length(t)-(i-1))).point1; lines(t(length(t)-(i-1))).point2];
        plot(xy{i}(:,1),xy{i}(:,2),'LineWidth',2,'Color','blue')
    end
    temp=median(thetax);
    n0=0;
    for i=1:N
        if(abs(thetax(i)-temp)<=15)
            xtx(i)=thetax(i);
            n0=n0+1;
        else
            xtx(i)=0;
        end
    end
    if n0==N
        thetaz=sum(xtx)/n0+rc;
        if thetaz<-60
            thetaz=thetaz+180;
        end
    else
        thetaz=0;
    end
    rc=rc+10;
end
end