function [Width_Lane] = widthfind(I)

SlopeThreshold=0.002;
AmpThreshold=0;
smoothwidth=2;
peakgroup=1;
smoothtype=5;
y=psd(sum(I,1),size(I,2));
%y=y.^2;
y=imresize(y,[500,1]);
%y=y(:,1);
P=peakfind(1:size(y,1),y,SlopeThreshold,AmpThreshold,smoothwidth,peakgroup,smoothtype);

B=P(:,2)>500;
P(B,:)=[];

[PS IX]=max(P(:,3));
Width_Lane=size(I,2)/P(IX,2)*2;