关于MATLAB中Hough变换提取直线

，本人正在利用Hough变换进行直线提取，现在已经对图像进行了分割和数学形态学的处理，可是在Hough变换提取直线是怎么都不对，求一个正确的Hough 变换的程序!急啊！先谢谢各位了！附上经数学形态学处理后的照片。目的是把道路的两条边界线提取出来。

1. clear all
   
2. close all
   
3. clc
   
4. I=imread('2220.jpg');
   
5. BW=im2bw(I);
   
6. BW=edge(BW,'canny');
   
7. % I=imdilate(I,strel('disk',8));
   
8. % I=imerode(I,strel('disk',8));
   
9. % BW=bwmorph(I,'thin',20);
   
10. %%
    
11. 
    
12. [H,T,R] = hough(BW);
    
13. imshow(H,[],'XData',T,'YData',R,...
    
14. 'InitialMagnification','fit');
    
15. xlabel('\theta'), ylabel('\rho');
    
16. axis on, axis normal, hold on;
    
17. P = houghpeaks(H,10,'threshold',ceil(0.3*max(H(:))));
    
18. x = T(P(:,2)); y = R(P(:,1));
    
19. plot(x,y,'s','color','white');
    
20. lines = houghlines(BW,T,R,P,'FillGap',5,'MinLength',7);
    
21. figure,imshow(BW), hold on
    
22. max_len = 0;
    
23. %%
    
24. 
    
25. for k = 1:length(lines)
    
26. xy = [lines(k).point1; lines(k).point2];
    
27. plot(xy(:,1),xy(:,2),'LineWidth',2,'Color','green');
    
28. 
    
29. % Plot beginnings and ends of lines
    
30. plot(xy(1,1),xy(1,2),'x','LineWidth',2,'Color','yellow');
    
31. plot(xy(2,1),xy(2,2),'x','LineWidth',2,'Color','red');
    
32. 
    
33. % Determine the endpoints of the longest line segment
    
34. len = norm(lines(k).point1 - lines(k).point2);
    
35. Len(k)=len
    
36. if ( len > max_len)
    
37. max_len = len
    
38. xy_long = xy
    
39. end
    
40. end
    
41. 
    
42. % highlight the longest line segment
    
43. plot(xy_long(:,1),xy_long(:,2),'LineWidth',2,'Color','blue');
    
44. 
    
45. %%
    
46. [L1 Index1]=max(Len(:))
    
47. Len(Index1)=0
    
48. [L2 Index2]=max(Len(:))
    
49. 
    
50. %%
    
51. %
    
52. x1=[lines(Index1).point1(1) lines(Index1).point2(1)]
    
53. y1=[lines(Index1).point1(2) lines(Index1).point2(2)]
    
54. x2=[lines(Index2).point1(1) lines(Index2).point2(1)]
    
55. y2=[lines(Index2).point1(2) lines(Index2).point2(2)]
    
56. 
    
57. %%
    
58. K1=(lines(Index1).point1(2)-lines(Index1).point2(2))/(lines(Index1).point1(1)-lines(Index1).point2(1))
    
59. K2=(lines(Index2).point1(2)-lines(Index2).point2(2))/(lines(Index2).point1(1)-lines(Index2).point2(1))
    
60. %%
    
61. hold on
    
62. [m,n] = size(BW); % 尺寸
    
63. BW1=zeros(m,n);
    
64. b1=y1(1)-K1*x1(1)
    
65. b2=y2(1)-K2*x2(1)
    
66. for x=1:n
    
67. for y=1:m
    
68. if y==round(K1*x+b1)|y==round(K2*x+b2)
    
69. BW1(y,x)=1;
    
70. 
    
71. end
    
72. 
    
73. end
    
74. end
    
75. for x=1:n
    
76. for y=1:m
    
77. 
    
78. if ceil(K1*x+b1)==ceil(K2*x+b2)
    
79. y1=round(K1*x+b1)
    
80. BW1(1:y1-1,:)=0;
    
81. end
    
82. end
    
83. end
    
84. figure,imshow(BW1)