%對矩陣取自適應閾值
function out=ada_thr(c,n,a0)

[row,col]=size(c);

m1=(n+1)/2;%n為奇數是模板的大小
m2=(n-1)/2;
temp_c=c;
for irow=m1:(row-m1)
    for jcol=m1:(col-m1)
        if c(irow,jcol)>0
           lefttop_h=irow-m2;%左上角橫坐標
           lefttop_v=jcol-m2;%左上角縱坐標
           sub_c=sub_m(c,lefttop_h,lefttop_v,n);
           mean_array=sum(sub_c);
           adapt_thr=sum(mean_array)*a0;
           temp_c(irow,jcol)=wthresh(c(irow,jcol),'h',adapt_thr);
        end
    end
end
out=temp_c;