opencv for python

opencv显示图像：

  # -*- coding: UTF-8 -*-

 import numpy as np

 import cv2

 from matplotlib import pyplot as plt

 img=cv2.imread("cat.png",5)   #载入

 cv2.imshow('image',img)     #显示

 k=cv2.waitKey(0)&0xFF     #读取键盘输入，参数为在x毫秒内读取，x=0是无限等待读取

 while(k!=27 and k!=ord('s')):

     k=cv2.waitKey(0)&0xFF

 if k==27:

     cv2.destroyAllWindows()

 elif k==ord('s'):

     cv2.imwrite('mess.png',img)

     cv2.destroyAllWindows()      #关闭窗口，参数可以为窗口名

opencv载入图像，matplotlib显示：

  # -*- coding: UTF-8 -*-

 import numpy as np

 import cv2

 from matplotlib import pyplot as plt

 img=cv2.imread('cat.png')

 plt.imshow(img)

 plt.show()

注：彩色图像使用OpenCV 加载时是BGR 模式。但是Matplotib 是RGB模式。所以彩色图像如果已经被OpenCV 读取，那它将不会被Matplotib 正确显示。

简单画图：

  # -*- coding: UTF-8 -*-

 import numpy as np

 import cv2

 from matplotlib import pyplot as plt

 cv2.namedWindow('hello')

 img=np.zeros((512,512,3),np.uint8) #创建一张空图片

 cv2.line(img,(60,90),(511,511),(255,0,0),6);

 cv2.rectangle(img,(100,70),(300,300),(100,100,100),5)

 cv2.circle(img,(200,200),60,(0,250,0),2)

 font=cv2.FONT_HERSHEY_SIMPLEX

 cv2.putText(img,'opencv',(60,400),font,4,(25,25,90),2)

 cv2.imshow('hello',img)

 cv2.waitKey(0)

 cv2.destroyAllWindows()

鼠标事件：

  # -*- coding: UTF-8 -*-

 import numpy as np

 import cv2

 from matplotlib import pyplot as plt

 #鼠标事件回调函数 函数参数统一如此

 def draw_rectangle(event,x,y,flags,param):

     if event==cv2.EVENT_LBUTTONDBLCLK:

         cv2.rectangle(img,(x,y),(x+30,y+30),(250,20,20),5)

 img=np.zeros((512,512,3),np.uint8)

 cv2.namedWindow('hello')

 cv2.setMouseCallback('hello',draw_rectangle)

 while 1:

     cv2.imshow('hello',img)

     if cv2.waitKey(20)&0xFF==27:

         break;

 cv2.destroyAllWindows()

滑动条：

 # -*- coding: utf-8 -*-

 """

 Created on Sun Jan 5 13:51:34 2014

 @author: duan

 """

 import cv2

 import numpy as np

 def nothing(x):            #滑动条的位置，通常默认为pass

     pass

 # 创建一副黑色图像

 img=np.zeros((250,512,3),np.uint8)

 cv2.namedWindow('image')

 cv2.createTrackbar('R','image',0,255,nothing)    #创建滑动条    ，滑动条名称，显示窗口名称，范围，回调函数

 cv2.createTrackbar('G','image',0,255,nothing)

 cv2.createTrackbar('B','image',0,255,nothing)

 switch='0:OFF\n1:ON'

 cv2.createTrackbar(switch,'image',0,1,nothing)

 while(1):

     cv2.imshow('image',img)

     k=cv2.waitKey(20)&0xFF

     if k==27:

         break

     r=cv2.getTrackbarPos('R','image')

     g=cv2.getTrackbarPos('G','image')

     b=cv2.getTrackbarPos('B','image')

     s=cv2.getTrackbarPos(switch,'image')

     if s==0:

         img[:]=100

     else:

         img[:]=[b,g,r]

 cv2.destroyAllWindows()

利用滑动条改变颜色画圆：

 # -*- coding: utf-8 -*-

 import cv2

 import numpy as np

 r,b,g=0,0,0

 def nothing(x):            #滑动条的位置，通常默认为pass

     pass

 def draw_circle(event,x,y,flags,param):

     if event==cv2.EVENT_LBUTTONDBLCLK:

         cv2.circle(img1,(x,y),10,(b,g,r),-1)

 # 创建一副黑色图像

 img=np.zeros((250,512,3),np.uint8)

 img1=np.zeros((250,512,3),np.uint8)

 cv2.namedWindow('image')

 cv2.namedWindow('win')

 cv2.createTrackbar('R','image',0,255,nothing)    #创建滑动条    ，滑动条名称，显示窗口名称，范围，回调函数

 cv2.createTrackbar('G','image',0,255,nothing)

 cv2.createTrackbar('B','image',0,255,nothing)

 cv2.setMouseCallback('win',draw_circle)

 while(1):

     cv2.imshow('win',img1)

     cv2.imshow('image',img)

     if cv2.waitKey(20)&0xFF==27:

         break

     r=cv2.getTrackbarPos('R','image')

     g=cv2.getTrackbarPos('G','image')

     b=cv2.getTrackbarPos('B','image')

     img[:]=[b,g,r]

 cv2.destroyAllWindows()

巴特西

opencv for python

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