import cv2
import numpy as np
import time

lowThreshold = 0
max_lowThreshold = 100

maxThreshold = 100
max_maxThreshold = 200
kernel_size = 3

def canny_low_threshold(intial):
    blur = cv2.GaussianBlur(img, (3, 3), 0)
    canny = cv2.Canny(blur, intial,maxThreshold)  # x是最小阈值,y是最大阈值
    cv2.imshow('canny', canny)

def canny_max_threshold(intial):
    blur = cv2.GaussianBlur(img, (3, 3), 0)
    canny = cv2.Canny(blur, lowThreshold,intial)  # x是最小阈值,y是最大阈值
    cv2.imshow('canny', canny)

img = cv2.imread('pic/1.png',0)   # 后面参数0即是以灰度读取

cv2.namedWindow('canny', cv2.WINDOW_NORMAL | cv2.WINDOW_KEEPRATIO)
cv2.createTrackbar('Min threshold', 'canny', lowThreshold, max_lowThreshold, canny_low_threshold)
cv2.createTrackbar('Max threshold', 'canny', maxThreshold, max_maxThreshold, canny_max_threshold)
canny_low_threshold(0)

if cv2.waitKey(0) == 27:    # 27是ESC键值
    cv2.destroyAllWindows()