added more image processing basics in opencv-py

Python/OpenCV/Flipping.py

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+# Flipping Images - Horizontally, Vertically, Horizontally & Vertically
+
+# Import Computer Vision package - cv2
+import cv2
+
+# Read the image using imread built in function
+image = cv2.imread('image_1.jpg')
+
+# Display original image using imshow built in function
+cv2.imshow("Original-Press any Key to contd", image)
+
+# Wait until any key is pressed
+cv2.waitKey(0)
+
+# cv2.flip is used to flip images
+# Horizontal flipping of images using value '1'
+flipping = cv2.flip(image, 1)
+
+# Display horizontally flipped image
+cv2.imshow("Horizontal Flipping", flipping)
+
+# Wait until any key is pressed
+cv2.waitKey(0)
+
+# Vertical flipping of images using value '0'
+flipping = cv2.flip(image, 0)
+
+# Display vertically flipped image
+cv2.imshow("Vertical Flipping", flipping)
+
+# Wait until any key is pressed
+cv2.waitKey(0)
+
+# Horizontal & Vertical flipping of images using value '-1'
+flipping = cv2.flip(image, -1)
+
+# Display horizontally & vertically flipped image
+cv2.imshow("Horizontal & Vertical Flipping", flipping)
+
+# Wait until any key is pressed
+cv2.waitKey(0)
+
+# Close all windows
+cv2.destroyAllWindows()
+

Python/OpenCV/Scaling.py

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+# Scaling (Resizing) Images - Cubic, Area, Linear Interpolations
+# Interpolation is a method of estimating values between known data points 
+
+# Import Computer Vision package - cv2
+import cv2
+
+# Import Numerical Python package - numpy as np
+import numpy as np
+
+# Read the image using imread built-in function
+image = cv2.imread('image_2.jpg')
+
+# Display original image using imshow built-in function
+cv2.imshow("Original", image)
+
+# Wait until any key is pressed
+cv2.waitKey()
+
+# cv2.resize(image, output image size, x scale, y scale, interpolation)
+
+# Scaling using cubic interpolation
+scaling_cubic = cv2.resize(image, None, fx=.75, fy=.75, interpolation = cv2.INTER_CUBIC)
+
+# Display cubic interpolated image
+cv2.imshow('Cubic Interpolated', scaling_cubic)
+
+# Wait until any key is pressed
+cv2.waitKey()
+
+# Scaling using area interpolation
+scaling_skewed = cv2.resize(image, (600, 300), interpolation = cv2.INTER_AREA)
+
+# Display area interpolated image
+cv2.imshow('Area Interpolated', scaling_skewed) 
+
+# Wait until any key is pressed
+cv2.waitKey()
+
+# Scaling using linear interpolation
+scaling_linear  = cv2.resize(image, None, fx=0.5, fy=0.5, interpolation = cv2.INTER_LINEAR)
+
+# Display linear interpolated image
+cv2.imshow('Linear Interpolated', scaling_linear) 
+
+# Wait until any key is pressed
+cv2.waitKey()
+
+# Close all windows
+cv2.destroyAllWindows()

Python/OpenCV/Varying_Brightness.py

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+# Varying Brightness of Images using Add and Subtract Operations
+
+# Import Computer Vision package - cv2
+import cv2
+
+# Import Numerical Python package - numpy as np
+import numpy as np
+
+# Read the image using imread built-in function
+image = cv2.imread('image_2.jpg')
+
+# Display original image using imshow built-in function
+cv2.imshow("Original", image)
+
+# Wait until any key is pressed
+cv2.waitKey(0)
+
+# np.ones returns an array of given shape and type, filled with ones
+# np.ones(shape, dtype)
+
+matrix = np.ones(image.shape, dtype = "uint8") * 120 
+# image.shape: gives takes the shape of original image
+# uint8: unsigned integer (0 to 255)
+# matrix: contains ones, having same dimension as original image but mutlipied by 120
+
+# Adding matrix to orginal image, increases brightness 
+add = cv2.add(image, matrix)
+
+# Display added image
+cv2.imshow("Added", add)
+
+# Wait until any key is pressed
+cv2.waitKey(0)
+
+# Subtracting matrix and original image, decreases brightness
+subtract = cv2.subtract(image, matrix)
+
+# Display subtracted image
+cv2.imshow("Subtracted", subtract)
+
+# Wait untill any key is pressed
+cv2.waitKey(0)
+
+# Close all windows
+cv2.destroyAllWindows()