www.pudn.com > houghlines00.rar > houghlines.m

function lines=houghlines(f,theta,rho,rr,cc,fillgap,minlength) 
 
if nargin<6 
	fillgap =20; 
end 
if nargin<7 
	minlength=40; 
end 
 
numlines=0;lines=struct([]); 
for k=1:length(rr) 
	rbin=rr(k);cbin=cc(k); 
 
	%Get all pixels associated with Hough transform cell. 
	[r,c]=houghpixels(f,theta,rho,rbin,cbin); 
	if isempty(r) 
		continue 
	end 
	 
%Rotate the pixel locations about (1,1) so that they lie approximately along a %vertical line. 
	omega=(90-theta(cbin))*pi/180; 
T=[cos(omega) sin(omega); -sin(omega) cos(omega)]; 
xy=[r-1 c-1]*T; 
x=sort(xy(:,1)); 
 
%Find the gaps larger than the threshold. 
diff_x=[diff(x);Inf]; 
idx=[0;find(diff_x>fillgap)]; 
for p=1:length(idx)-1 
	x1=x(idx(p)+1);x2=x(idx(p+1)); 
	linelength=x2-x1; 
if linelength>=minlength 
	point1=[x1 rho(rbin)];point2=[x2 rho(rbin)]; 
	%Rotate the end-point locations back to the original angle. 
	Tinv=inv(T); 
point1=point1*Tinv; point2=point2*Tinv; 
numlines=numlines+1; 
lines(numlines).point1=point1+1; 
lines(numlines).point2=point2+1; 
lines(numlines).length=linelength; 
lines(numlines).theta=theta(cbin); 
lines(numlines).rho=rho(rbin); 
		end 
	end 
end