opencv 霍夫曼变换 直线提取

import cv2
import numpy as np  
 
img = cv2.imread("hd.jpeg", 0)
 
img = cv2.GaussianBlur(img,(3,3),0)
edges = cv2.Canny(img, 50, 150, apertureSize = 3)
lines = cv2.HoughLines(edges,1,np.pi/10,118) #这里对最后一个参数使用了经验型的值
result = img.copy()

for m in range(lines.ndim):
    for line in lines[m]:
    	rho = line[0] #第一个元素是距离rho
    	theta= line[1] #第二个元素是角度theta
    #	print rho
    #	print theta
    	if  (theta < (np.pi/4. )) or (theta > (3.*np.pi/4.0)): #垂直直线
                    #该直线与第一行的交点
    		pt1 = (int(rho/np.cos(theta)),0)
    		#该直线与最后一行的焦点
    		pt2 = (int((rho-result.shape[0]*np.sin(theta))/np.cos(theta)),result.shape[0])
    		#绘制一条白线
    		cv2.line( result, pt1, pt2, (255))
    	else: #水平直线
    		# 该直线与第一列的交点
    		pt1 = (0,int(rho/np.sin(theta)))
    		#该直线与最后一列的交点
    		pt2 = (result.shape[1], int((rho-result.shape[1]*np.cos(theta))/np.sin(theta)))
    		#绘制一条直线
    		cv2.line(result, pt1, pt2, (255), 1)
 
cv2.imshow('Canny', edges )
cv2.imshow('Result', result)
cv2.waitKey(0)
cv2.destroyAllWindows()