四叉树错误代码，求大神!!!

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function quadtree(2)
f=imread(2);
q=2^nextpow2(max(size(f)));
[m n]=size(f);
f=padarray(f,[q-m,q-n],'post');
mindim=2;
s=qtdecomp(f,split,mindim,predicate);
lmax=full(max(s(:)));
g=zeros(size(f));
for k=1:lmax
[vals.r,c]=qtgetblk(f,s,k);
if ~isempty(vals)
for i=l:length(r)
xlow=r(i);ylow=c(i);
xhigh=xlow+k-1;
yhigh=ylow+k-1;
region=f(xlow:xhigh,ylow:yhigh);
flag=feval(predicate,region);
if flag
g(xlow:xhigh,ylow:yhigh)=1;
marker(xlow,ylow)=1;
end
end
end
end
g=bwlabel(imreconstruct(marker,g));
g=g(1:m,1:n);
f=f(1:m,1:n);
subplot(121),imshow(f),title('');
subplot(122),imshow(g),title('');
end
function v=split(b,mindim,fun)
k=size(b,3);
v(1:k)=false;
for i=1:k
quadrgn=b(:,:,i);
if size(quadrgn,1)<=mindim
v(i)=false;
continue;y
end
flag=feval(fun,quadrgn);
if flag
v(i)=true;
end
end
end
function flag=predicate(region)
sd=std2(region);
m=mean2(region);
flag=(sd>5)&(m>0)&(m<200);
end
错误提示为??? function quadtree(2)
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Error: Function definitions are not permitted in this context.