OpenCV for Python

OPENCV Display Image:

1  #-*-coding:utf-8-*-2 ImportNumPy as NP3 ImportCv24  fromMatplotlibImportPyplot as Plt5 6Img=cv2.imread ("Cat.png", 5)#Gta5-In7Cv2.imshow ('Image', IMG)#Show8K=cv2.waitkey (0) &0xff#read keyboard input, parameter is read in x milliseconds, x=0 is infinite wait read9  while(k!=27 andK!=ord ('s')):TenK=cv2.waitkey (0) &0xff One ifK==27: A cv2.destroyallwindows () - elifK==ord ('s'): -Cv2.imwrite ('Mess.png', IMG) theCv2.destroyallwindows ()#Close window, parameter can be window name

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OpenCV load image, Matplotlib display:

 1  #   2  import  Span style= "color: #000000;" > NumPy as NP  3  import   Cv2  4  from  matplotlib import   Pyplot as plt  5  6  img=cv2.imread ( cat.png  Span style= "color: #800000;" " "  7   8  plt.show () 

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Note: Color images are BGR mode when loaded with OPENCV. But Matplotib is RGB mode. So if the color image has been read by OPENCV, it will not be displayed correctly by Matplotib.

Simple drawing:

1  #-*-coding:utf-8-*-2 ImportNumPy as NP3 ImportCv24  fromMatplotlibImportPyplot as Plt5Cv2.namedwindow ('Hello')6Img=np.zeros ((512,512,3), np.uint8)#Create an empty picture7Cv2.line (IMG, (60,90), (511,511), (255,0,0), 6);8Cv2.rectangle (IMG, (100,70), (300,300), (100,100,100), 5)9Cv2.circle (IMG, (200,200), 60, (0,250,0), 2)TenFont=Cv2. Font_hershey_simplex OneCv2.puttext (IMG,'OpenCV', (60,400), font,4, (25,25,90), 2) ACv2.imshow ('Hello', IMG) -  - cv2.waitkey (0) theCv2.destroyallwindows ()

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Mouse events:

1  #-*-coding:utf-8-*-2 ImportNumPy as NP3 ImportCv24  fromMatplotlibImportPyplot as Plt5 #Mouse Event callback function function parameters Unified so6 defDraw_rectangle (event,x,y,flags,param):7     ifevent==Cv2. EVENT_LBUTTONDBLCLK:8Cv2.rectangle (IMG, (x, y), (x+30,y+30), (250,20,20), 5)9 TenImg=np.zeros ((512,512,3), np.uint8) OneCv2.namedwindow ('Hello') ACv2.setmousecallback ('Hello', Draw_rectangle) -  while1: -Cv2.imshow ('Hello', IMG) the     ifCv2.waitkey (&0xff==27): -          Break; -Cv2.destroyallwindows ()

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Slide Bar:

1 #-*-coding:utf-8-*-2 """3 Created on Sun Jan 5 13:51:344 @author: Duan5 """6 ImportCv27 ImportNumPy as NP8 defNothing (x):#the position of the slider, usually the default is pass9     PassTen #create a pair of black images OneImg=np.zeros ((250,512,3), np.uint8) ACv2.namedwindow ('Image') -Cv2.createtrackbar ('R','Image', 0,255,nothing)#Create slider bar, slide bar name, display window name, range, callback function -Cv2.createtrackbar ('G','Image', 0,255, nothing) theCv2.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 (&0XFF) +     ifK==27: A          Break atR=cv2.gettrackbarpos ('R','Image') -G=cv2.gettrackbarpos ('G','Image') -B=cv2.gettrackbarpos ('B','Image') -S=cv2.gettrackbarpos (Switch,'Image') -     ifs==0: -img[:]=100 in     Else: -img[:]=[B,g,r] toCv2.destroyallwindows ()

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Use the slider to change the color of the circle:

1 #-*-coding:utf-8-*-2 ImportCv23 ImportNumPy as NP4r,b,g=0,0,05 defNothing (x):#the position of the slider, usually the default is pass6     Pass7 8 defdraw_circle (event,x,y,flags,param):9     ifevent==Cv2. EVENT_LBUTTONDBLCLK:TenCv2.circle (IMG1, (x, y), ten, (B,g,r), 1) One  A #create a pair of black images -Img=np.zeros ((250,512,3), np.uint8) -Img1=np.zeros ((250,512,3), np.uint8) the  -Cv2.namedwindow ('Image') -Cv2.namedwindow ('win') -  +Cv2.createtrackbar ('R','Image', 0,255,nothing)#Create slider bar, slide bar name, display window name, range, callback function -Cv2.createtrackbar ('G','Image', 0,255, nothing) +Cv2.createtrackbar ('B','Image', 0,255, nothing) A  atCv2.setmousecallback ('win', Draw_circle) -  while(1): -Cv2.imshow ('win', IMG1) -Cv2.imshow ('Image', IMG) -     ifCv2.waitkey (&0xff==27): -          Break     inR=cv2.gettrackbarpos ('R','Image') -G=cv2.gettrackbarpos ('G','Image') toB=cv2.gettrackbarpos ('B','Image') +img[:]=[B,g,r] -Cv2.destroyallwindows ()

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OpenCV for Python