# -*- coding: utf-8 -*-
"""
Created on Thu Sep 13 14:23:32 2018
@author: Leon
内容：
对图片进行边缘检测；
添加滑动条，可自由调整阈值上下限。
"""
 
import cv2
import numpy as np
 
def nothing(x):
  pass
 
cv2.namedWindow('Canny',0)
# 创建滑动条
cv2.createTrackbar('minval','Canny',0,255,nothing)
cv2.createTrackbar('maxval','Canny',0,255,nothing)
 
img = cv2.imread('Tree.jpg',0)
 
# 高斯滤波去噪
img = cv2.GaussianBlur(img,(3,3),0)
edges =img
 
k=0
while(1):
 
  key = cv2.waitKey(50) & 0xFF
  if key == ord('q'):
    break
  # 读取滑动条数值
  minval = cv2.getTrackbarPos('minval','Canny')
  maxval = cv2.getTrackbarPos('maxval','Canny')
  edges = cv2.Canny(img,minval,maxval)
  
  # 拼接原图与边缘监测结果图
  img_2 = np.hstack((img,edges))
  cv2.imshow('Canny',img_2)
 
cv2.destroyAllWindows()