clear;
clc;
I??=?imread（‘C:\Program?Files\MATLAB71\toolbox\images\imdemos\gg.jpg‘）;
I=rgb2gray（I）;
BW?=?edge（I‘canny‘）;
[HTR]?=?hough（BW）;
imshow（H[]‘XData‘T‘YData‘R...
????????????‘InitialMagnification‘‘fit‘）;
xlabel（‘\theta‘）?ylabel（‘\rho‘）;
axis?on?axis?normal?hold?on;
P??=?houghpeaks（H5‘threshold‘ceil（0.3*max（H（:））））;
x?=?T（P（:2））;?y?=?R（P（:1））;
plot（xy‘s‘‘color‘‘white‘）;
%?Find?lines?and?plot?them
lines?=?houghlines（BWTRP‘FillGap‘5‘MinLength‘7）;
figure?imshow（I）?hold?on
max_len?=?0;
longest_line_index=0;
for?k?=?1:length（lines）
???xy?=?[lines（k）.po