python+opencv實現霍夫變換檢測直線
阿新 • • 發佈:2019-01-29
功能:
建立一個滑動條來控制檢測直線的長度閾值,即大於該閾值的檢測出來,小於該閾值的忽略
注意:這裡用的函式是HoughLinesP而不是HoughLines,因為HoughLinesP直接給出了直線的斷點,在畫出線段的時候可以偷懶
程式碼:
# -*- coding: utf-8 -*-
import cv2
#兩個回撥函式
def HoughLinesP(minLineLength):
global minLINELENGTH
minLINELENGTH = minLineLength + 1
print "minLINELENGTH:",minLineLength + 1
tempIamge = scr.copy()
lines = cv2.HoughLinesP( edges, 1, cv2.cv.CV_PI/180, minLINELENGTH, 0 )
for x1,y1,x2,y2 in lines[0]:
cv2.line(tempIamge,(x1,y1),(x2,y2),(0,255,0),1)
cv2.imshow(window_name,tempIamge)
#臨時變數
minLineLength = 20
#全域性變數
minLINELENGTH = 20
max_value = 100
window_name = "HoughLines Demo"
trackbar_value = "minLineLength"
#讀入圖片,模式為灰度圖,建立視窗
scr = cv2.imread("G:\\homework\\building.bmp")
gray = cv2.cvtColor(scr,cv2.COLOR_BGR2GRAY)
img = cv2.GaussianBlur(gray,(3,3),0)
edges = cv2.Canny(img, 50, 150, apertureSize = 3)
cv2.namedWindow(window_name)
#建立滑動條
cv2.createTrackbar( trackbar_value, window_name, \
minLineLength, max_value, HoughLinesP)
#初始化
HoughLinesP(20)
if cv2.waitKey(0) == 27:
cv2.destroyAllWindows()
呼叫:
>>> import os
>>> os.chdir("g:\homework")
>>>
>>> import HoughLines
minLINELENGTH: 20
minLINELENGTH: 21
minLINELENGTH: 22
minLINELENGTH: 23
minLINELENGTH: 25
minLINELENGTH: 26
minLINELENGTH: 27
minLINELENGTH: 28