OpenCV Python – Reading an image
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The CV2 package (name of OpenCV-Python library) provides the imread() function to read an image.
The command to read an image is as follows −
img=cv2.imread(filename, flags)
The flags parameters are the enumeration of following constants −
- cv2.IMREAD_COLOR (1) − Loads a color image.
- cv2.IMREAD_GRAYSCALE (0) − Loads image in grayscale mode
- cv2.IMREAD_UNCHANGED (-1) − Loads image as such including alpha channel
The function will return an image object, which can be rendered using imshow() function. The command for using imshow() function is given below −
cv2.imshow(window-name, image)
The image is displayed in a named window. A new window is created with the AUTOSIZE flag set. The WaitKey() is a keyboard binding function. Its argument is the time in milliseconds.
The function waits for specified milliseconds and keeps the window on display till a key is pressed. Finally, we can destroy all the windows thus created.
The function waits for specified milliseconds and keeps the window on display till a key is pressed. Finally, we can destroy all the windows thus created.
The program to display the OpenCV logo is as follows −
import numpy as np import cv2 # Load a color image in grayscale img = cv2.imread(''OpenCV_Logo.png'',1) cv2.imshow(''image'',img) cv2.waitKey(0) cv2.destroyAllWindows()
The above program displays the OpenCV logo as follows −
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