add opencv basic tutorial

Author: manthan89-py

.gitignore

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+output.avi
+.vscode/

.vscode/settings.json

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+{
+"python.pythonPath": "opencv\\Scripts\\python.exe"
+}

add_text_to_videos.py

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+import cv2
+import datetime
+cap = cv2.VideoCapture(0)
+
+print(cap.get(cv2.CAP_PROP_FRAME_HEIGHT))
+print(cap.get(cv2.CAP_PROP_FRAME_WIDTH))
+
+# 3: width, 4: height
+# you can only able to some fix height and width like 1280x720
+# If you set 700x700 then it will take 640x480
+# If you set 3000x3000 then it will take 1280x720
+
+cap.set(cv2.CAP_PROP_FRAME_WIDTH , 1208)
+cap.set(cv2.CAP_PROP_FRAME_HEIGHT , 720)
+
+print(cap.get(cv2.CAP_PROP_FRAME_HEIGHT))
+print(cap.get(cv2.CAP_PROP_FRAME_WIDTH))
+
+while(cap.isOpened()):
+ret , frame = cap.read()
+if ret == True:
+font = cv2.FONT_HERSHEY_SIMPLEX
+text = 'Width: '+str(cap.get(3)) +' Height: '+str(cap.get(4))
+date = 'Date: '+ str(datetime.datetime.now())
+
+cv2.putText(frame , text ,(10,50) , font , 1 ,(0,255,255) , 2 , lineType=cv2.LINE_AA)
+
+cv2.putText(frame , date ,(10,90) , font , 1 ,(0,255,255) , 2 , lineType=cv2.LINE_AA)
+
+cv2.imshow('image' , frame)
+
+if cv2.waitKey(1) & 0xFF == ord('q'):
+break
+else:
+break
+
+cap.release()
+cv2.destroyAllWindows()

basic_operations_opencv.py

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+import numpy as np
+import cv2
+
+img = cv2.imread('messi5.jpg')
+
+print(img.shape) # row , column , channles
+print(img.size) # total number of pixels
+print(img.dtype) # image datatype
+
+b,g,r = cv2.split(img)
+
+img = cv2.merge((b,g,r))
+
+cv2.imshow('image' , img)
+cv2.waitKey(0)
+cv2.destroyAllWindows()

draw_shapes.py

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+import cv2
+import numpy as np
+# img = cv2.imread('lena.jpg', 1)
+
+# img with numpy
+img = np.zeros([600,600,3] , np.uint8 )
+
+## Draw Line
+img = cv2.line(img, (0,0),(255,255),(255,0,0),thickness=3)
+
+## Arrowed line
+img = cv2.arrowedLine(img, (0,255),(255,255),(0,255,0),thickness=3)
+
+## Rectangle
+img = cv2.rectangle(img , (384,0),(450,330),(0,0,255),thickness=5)
+# if thickness = -1 then it will filled with given color
+
+## Circle
+img = cv2.circle(img, (447,63),radius=63,color = (255,34,135),thickness=-1)
+
+## Put Text
+font = cv2.FONT_HERSHEY_SIMPLEX
+img = cv2.putText(img,'OpenCv',(10,450) ,font , 4 , (255,255,255), 10, cv2.LINE_AA)
+
+cv2.imshow('image',img)
+cv2.waitKey(0)
+cv2.destroyAllWindows()

first_tut.py

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+import cv2
+
+# img = cv2.imread('lena.jpg',-1)
+
+# cv2.imshow('image',img)
+
+# k = cv2.waitKey(0)
+
+# if k == 27:
+# cv2.destroyAllWindows()
+# elif k == ord('s'):
+# cv2.imwrite('lena_copy_2.png' , img)
+# cv2.destroyAllWindows()
+
+
+########## Video Capture ###########
+
+## If we want to load our video file we can do that by giving
+# name of file in video capture.
+
+cap = cv2.VideoCapture(0)
+
+fourcc = cv2.VideoWriter_fourcc(*'XVID') # need to save video
+
+out = cv2.VideoWriter('output.avi',fourcc , 20 , (640,480)) # save live video
+
+
+## isOpened is useful for to check if cap capture something.
+while(cap.isOpened()):
+ret , frame = cap.read()
+if ret == True:
+gray = cv2.cvtColor(frame , cv2.COLOR_BGR2GRAY)
+cv2.imshow('manthan' , gray)
+
+out.write(frame)
+
+print(cap.get(cv2.CAP_PROP_FRAME_HEIGHT)) # Frame height
+print(cap.get(cv2.CAP_PROP_FRAME_WIDTH)) # Frame width
+
+if cv2.waitKey(1) & 0xFF == ord('q'):
+break
+else:
+break
+
+cap.release()
+out.release()
+cv2.destroyAllWindows()
+
+

lena.jpg

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+import cv2
+import numpy as np
+
+def event_click(event , x , y , flags , param):
+# if event == cv2.EVENT_LBUTTONDOWN:
+# print(x ,' ', y)
+# strxy = str(x) + ', ' + str(y)
+# font = cv2.FONT_HERSHEY_SIMPLEX
+# cv2.putText(img ,strxy, (x,y) , font , 0.5 , (255,255,0), 2)
+# cv2.imshow('image' , img)
+# if event == cv2.EVENT_RBUTTONDOWN:
+# blue = img[y,x,0] # BLUE
+# green = img[y,x,1] # green
+# red = img[y,x,2] # red
+# strBGR = str(blue) + ', ' + str(green) +', ' + str(red)
+# font = cv2.FONT_HERSHEY_SIMPLEX
+# cv2.putText(img ,strBGR, (x,y) , font , 0.5 , (0,0,0), 2)
+# cv2.imshow('image' , img)
+
+####### Advanced Events ########
+# if event == cv2.EVENT_LBUTTONDOWN:
+# cv2.circle(img , (x,y) , 3 ,(0,0,255) , -1)
+# points.append((x,y))
+# if len(points) >= 2:
+# cv2.line(img , points[-1] , points[-2] ,(0,255,0) ,2 , lineType=cv2.LINE_AA)
+# cv2.imshow('image' , img)
+if event == cv2.EVENT_LBUTTONDOWN:
+blue = img[x,y,0] # BLUE
+green = img[x,y,1] # green
+red = img[x,y,2] # red
+cv2.circle(img , (x,y) , 3 ,(0,0,255) , -1)
+mycolorimage = np.zeros([512,512,3] , np.uint8)
+mycolorimage[:] = [blue,green,red]
+cv2.imshow('color image' , mycolorimage)
+
+
+
+
+
+# img = np.zeros([512,512,3] , np.uint8)
+img = cv2.imread('lena.jpg')
+cv2.imshow('image' , img)
+points = []
+# window name must be same
+cv2.setMouseCallback('image' , event_click)
+
+cv2.waitKey(0)
+cv2.destroyAllWindows()