feat: add example codes for OpenCV

CV/OpenCV/.gitignore

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+.dist
+.DS_Store

CV/OpenCV/Interface/blank_img.py

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+import cv2
+import numpy as np
+
+img = np.full((500,500,3), 255, dtype=np.uint8)
+cv2.imwrite('./img/blank_500.jpg', img)

CV/OpenCV/Interface/draw_circle.py

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+import cv2
+
+img = cv2.imread('../img/blank_500.jpg')
+
+
+cv2.circle(img, (150, 150), 100, (255,0,0))
+cv2.circle(img, (300, 150), 70, (0,255,0), 5)
+cv2.circle(img, (400, 150), 50, (0,0,255), -1)
+
+
+cv2.ellipse(img, (50, 300), (50, 50), 0, 0, 360, (0,0,255))
+cv2.ellipse(img, (150, 300), (50, 50), 0, 0, 180, (255,0,0))
+cv2.ellipse(img, (200, 300), (50, 50), 0, 181, 360, (0,0,255))    
+
+
+cv2.ellipse(img, (325, 300), (75, 50), 0, 0, 360, (0,255,0))
+cv2.ellipse(img, (450, 300), (50, 75), 0, 0, 360, (255,0,255))
+
+
+cv2.ellipse(img, (50, 425), (50, 75), 15, 0, 360, (0,0,0))
+cv2.ellipse(img, (200, 425), (50, 75), 45, 0, 360, (0,0,0))
+
+
+cv2.ellipse(img, (350, 425), (50, 75), 45, 0, 180, (0,0,255))
+cv2.ellipse(img, (400, 425), (50, 75), 45, 181, 360, (255,0,0))
+
+
+cv2.imshow('circle', img)
+cv2.waitKey(0)
+cv2.destroyAllWindows()

CV/OpenCV/Interface/draw_line.py

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+import cv2
+
+img = cv2.imread('../img/blank_500.jpg')
+
+cv2.line(img, (50, 50), (150, 50), (255,0,0))
+cv2.line(img, (200, 50), (300, 50), (0,255,0))
+cv2.line(img, (350, 50), (450, 50), (0,0,255))
+
+
+cv2.line(img, (100, 100), (400, 100), (255,255,0), 10)  
+cv2.line(img, (100, 150), (400, 150), (255,0,255), 10)
+cv2.line(img, (100, 200), (400, 200), (0,255,255), 10)
+cv2.line(img, (100, 250), (400, 250), (200,200,200), 10)
+cv2.line(img, (100, 300), (400, 300), (0,0,0), 10)
+
+
+cv2.line(img, (100, 350), (400, 400), (0,0,255), 20, cv2.LINE_4)
+cv2.line(img, (100, 400), (400, 450), (0,0,255), 20, cv2.LINE_8)
+cv2.line(img, (100, 450), (400, 500), (0,0,255), 20, cv2.LINE_AA)
+cv2.line(img, (0,0), (500,500), (0,0,255))                      
+
+cv2.imshow('lines', img)
+cv2.waitKey(0)
+cv2.destroyAllWindows()

CV/OpenCV/Interface/draw_poly.py

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+import cv2
+import numpy as np                          # 좌표 표현을 위한 numpy 모듈  ---①
+
+img = cv2.imread('../img/blank_500.jpg')
+
+
+
+pts1 = np.array([[50,50], [150,150], [100,140],[200,240]], dtype=np.int32)
+pts2 = np.array([[350,50], [250,200], [450,200]], dtype=np.int32)
+pts3 = np.array([[150,300], [50,450], [250,450]], dtype=np.int32)
+pts4 = np.array([[350,250], [450,350], [400,450], [300,450], [250,350]], dtype=np.int32) 
+
+
+cv2.polylines(img, [pts1], False, (255,0,0))
+cv2.polylines(img, [pts2], False, (0,0,0), 10)
+cv2.polylines(img, [pts3], True, (0,0,255), 10)
+cv2.polylines(img, [pts4], True, (0,0,0))
+
+cv2.imshow('polyline', img)
+cv2.waitKey(0)
+cv2.destroyAllWindows()

CV/OpenCV/Interface/draw_rect.py

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+import cv2
+
+img = cv2.imread('../img/blank_500.jpg')
+
+cv2.rectangle(img, (50, 50), (150, 150), (255,0,0) )
+cv2.rectangle(img, (300, 300), (100, 100), (0,255,0), 10 )
+cv2.rectangle(img, (450, 200), (200, 450), (0,0,255), -1 )
+
+cv2.imshow('rectangle', img)
+cv2.waitKey(0)
+cv2.destroyAllWindows()

CV/OpenCV/Interface/draw_text.py

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+import cv2
+
+img = cv2.imread('../img/blank_500.jpg')
+
+# sans-serif small
+cv2.putText(img, "Plain", (50, 30), cv2.FONT_HERSHEY_PLAIN, 1, (0, 0,0))            
+# sans-serif normal
+cv2.putText(img, "Simplex", (50, 70), cv2.FONT_HERSHEY_SIMPLEX, 1, (0, 0,0))        
+# sans-serif bold
+cv2.putText(img, "Duplex", (50, 110), cv2.FONT_HERSHEY_DUPLEX, 1, (0, 0,0))         
+# sans-serif normall X2  ---①
+cv2.putText(img, "Simplex", (200, 110), cv2.FONT_HERSHEY_SIMPLEX, 2, (0,0,250)) 
+
+# serif small
+cv2.putText(img, "Complex Small", (50, 180), cv2.FONT_HERSHEY_COMPLEX_SMALL, \
+            1, (0, 0,0))   
+# serif normal
+cv2.putText(img, "Complex", (50, 220), cv2.FONT_HERSHEY_COMPLEX, 1, (0, 0,0))
+# serif bold
+cv2.putText(img, "Triplex", (50, 260), cv2.FONT_HERSHEY_TRIPLEX, 1, (0, 0,0))               
+# serif normal X2  ---②
+cv2.putText(img, "Complex", (200, 260), cv2.FONT_HERSHEY_TRIPLEX, 2, (0,0,255))               
+
+# hand-wringing sans-serif
+cv2.putText(img, "Script Simplex", (50, 330), cv2.FONT_HERSHEY_SCRIPT_SIMPLEX, \
+            1, (0, 0,0)) 
+# hand-wringing serif
+cv2.putText(img, "Script Complex", (50, 370), cv2.FONT_HERSHEY_SCRIPT_COMPLEX, \
+            1, (0, 0,0)) 
+
+# sans-serif + italic ---③
+cv2.putText(img, "Plain Italic", (50, 430), \
+            cv2.FONT_HERSHEY_PLAIN | cv2.FONT_ITALIC, 1, (0, 0,0)) 
+# sarif + italic
+cv2.putText(img, "Complex Italic", (50, 470), \
+            cv2.FONT_HERSHEY_COMPLEX | cv2.FONT_ITALIC, 1, (0, 0,0)) 
+
+cv2.imshow('draw text', img)
+cv2.waitKey()
+cv2.destroyAllWindows()

CV/OpenCV/Interface/event_key.py

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+import cv2
+
+img_file = "../img/girl.jpg" 
+img = cv2.imread(img_file) 
+title = 'IMG'
+x, y = 100, 100
+
+while True:
+    cv2.imshow(title, img)
+    cv2.moveWindow(title, x, y)
+
+    key = cv2.waitKey(0) & 0xFF
+    print(key, chr(key))
+
+    if key == ord('h'):
+        x -= 10
+    elif key == ord('j'):
+        y += 10
+    elif key == ord('k'):
+        y -= 10
+    elif key == ord('l'):
+        x += 10
+    elif key == ord('q') or key == 27:
+        break
+        cv2.destroyAllWindows()
+    cv2.moveWindow(title, x, y )
+

CV/OpenCV/Interface/event_mouse_circle.py

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+import cv2
+
+title = 'mouse event'
+img = cv2.imread('../img/blank_500.jpg')
+cv2.imshow(title, img)
+
+
+def onMouse(event, x, y, flags, param):
+    print(event, x, y, )
+
+    if event == cv2.EVENT_LBUTTONDOWN:
+        cv2.circle(img, (x,y), 30, (0,0,0), -1)
+        cv2.imshow(title, img)
+
+
+cv2.setMouseCallback(title, onMouse)
+
+while True:
+    if cv2.waitKey(0) & 0xFF == 27:
+        break
+cv2.destroyAllWindows()

CV/OpenCV/Interface/event_mouse_circle_flag.py

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+import cv2
+
+
+title = 'mouse event'
+img = cv2.imread('../img/blank_500.jpg')
+cv2.imshow(title, img)
+
+
+colors = {'black':(0,0,0),
+         'red' : (0,0,255),
+         'blue':(255,0,0),
+         'green': (0,255,0) }
+
+
+def onMouse(event, x, y, flags, param):
+    print(event, x, y, flags)
+    color = colors['black']
+
+    if event == cv2.EVENT_LBUTTONDOWN:
+        if flags & cv2.EVENT_FLAG_CTRLKEY and flags & cv2.EVENT_FLAG_SHIFTKEY:
+            color = colors['green']
+
+        elif flags & cv2.EVENT_FLAG_SHIFTKEY:
+            color = colors['blue']
+
+        elif flags & cv2.EVENT_FLAG_CTRLKEY:
+            color = colors['red']
+
+        cv2.circle(img, (x,y), 30, color, -1) 
+        cv2.imshow(title, img)
+
+
+cv2.setMouseCallback(title, onMouse)
+
+while True:
+    if cv2.waitKey(0) & 0xFF == 27:
+        break
+cv2.destroyAllWindows()

CV/OpenCV/Interface/event_trackbar.py

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+import cv2
+import numpy as np
+
+win_name = 'Trackbar'
+
+img = cv2.imread('../img/blank_500.jpg')
+cv2.imshow(win_name,img)
+
+
+def onChange(x):                                        
+    print(x)
+
+    r = cv2.getTrackbarPos('R',win_name)               
+    g = cv2.getTrackbarPos('G',win_name)               
+    b = cv2.getTrackbarPos('B',win_name)               
+    print(r, g, b)
+    img[:] = [b,g,r]
+    cv2.imshow(win_name, img)
+
+
+cv2.createTrackbar('R', win_name, 255, 255, onChange)  
+cv2.createTrackbar('G', win_name, 255, 255, onChange)
+cv2.createTrackbar('B', win_name, 255, 255, onChange)
+
+while True:
+    if cv2.waitKey(1) & 0xFF == 27:
+        break
+
+cv2.destroyAllWindows()

CV/OpenCV/Interface/img_show.py

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+import cv2
+
+
+img_file = "../img/girl.jpg"
+img = cv2.imread(img_file)
+
+
+if img is not None:
+    cv2.imshow('IMG', img)
+    cv2.waitKey()
+    cv2.destroyAllWindows()
+else:
+    print('No image file.')

CV/OpenCV/Interface/img_show_gray.py

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+import cv2
+
+img_file = "../img/girl.jpg"
+
+# read image with gray scaling
+img = cv2.imread(img_file, cv2.IMREAD_GRAYSCALE)
+
+if img is not None:
+    cv2.imshow('IMG', img)
+    cv2.waitKey()
+    cv2.destroyAllWindows()
+else:
+    print('No image file.')

CV/OpenCV/Interface/img_write.py

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+import cv2
+
+img_file = '../img/girl.jpg'
+save_file = '../img/girl_gray.jpg'
+
+
+img = cv2.imread(img_file, cv2.IMREAD_GRAYSCALE)
+cv2.imshow(img_file, img)
+cv2.imwrite(save_file, img)
+cv2.waitKey()
+cv2.destroyAllWindows()

CV/OpenCV/Interface/video_cam.py

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+import cv2
+
+cap = cv2.VideoCapture(0)
+
+if cap.isOpened():
+    while True:
+        ret, img = cap.read()
+
+        if ret:
+            cv2.imshow('camera', img)
+            if cv2.waitKey(1) != -1:
+                break
+
+        else:
+            print('no frame')
+            break
+else:
+    print("can't open camera.")
+
+
+cap.release()
+cv2.destroyAllWindows()

CV/OpenCV/Interface/video_cam_rec.py

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+import cv2
+
+cap = cv2.VideoCapture(0)
+
+if cap.isOpened:
+    file_path = './record.avi'
+    fps = 30.0
+    fourcc = cv2.VideoWriter_fourcc(*'DIVX')
+    width = cap.get(cv2.CAP_PROP_FRAME_WIDTH)
+    height = cap.get(cv2.CAP_PROP_FRAME_HEIGHT)
+    size = (int(width), int(height))
+    out = cv2.VideoWriter(file_path, fourcc, fps, size)
+
+
+    while True:
+        ret, frame = cap.read()
+
+        if ret:
+            cv2.imshow('camera-recording',frame)
+            out.write(frame)
+            if cv2.waitKey(int(1000 / fps)) != -1: 
+                break
+        else:
+            print("no frame!")
+            break
+    out.release()
+
+else:
+    print("can't open camera!")
+
+cap.release()
+cv2.destroyAllWindows()

CV/OpenCV/Interface/video_cam_resize.py

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+import cv2
+
+
+cap = cv2.VideoCapture(0)
+width = cap.get(cv2.CAP_PROP_FRAME_WIDTH)
+height = cap.get(cv2.CAP_PROP_FRAME_HEIGHT)
+
+print("Original width: %d, height:%d" % (width, height) ) 
+
+cap.set(cv2.CAP_PROP_FRAME_WIDTH, 320)
+cap.set(cv2.CAP_PROP_FRAME_HEIGHT, 240)
+width = cap.get(cv2.CAP_PROP_FRAME_WIDTH)
+height = cap.get(cv2.CAP_PROP_FRAME_HEIGHT)
+
+print("Resized width: %d, height:%d" % (width, height) )
+
+if cap.isOpened():
+    while True:
+        ret, img = cap.read()
+        if ret:
+            cv2.imshow('camera', img)
+            if cv2.waitKey(1) != -1:
+                break
+        else:
+            print('no frame!')
+            break
+else:
+    print("can't open camera!")
+
+cap.release()
+cv2.destroyAllWindows()