[Python] OpenCV 彩色轉灰階(RGB to Gray)

第一種方式:

import cv2

image = cv2.imread(‘test.jpg’) #讀取影像

image_g = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY) #透過轉換函式轉為灰階影像

cv2.imwrite(‘test_g.jpg’, image_g) #儲存影像

第二種方式:

import cv2

image_g = cv2.imread(‘test.jpg’, 0) #直接以灰階方式讀取影像

cv2.imwrite(‘test_g.jpg’, image_g) #儲存影像

img = cv2.imread('gray.jpg',0)

0 for gray and 1 for color

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cv2.imread load an image with three channels unless CV_LOAD_IMAGE_GRAYSCALE is set.

>>> import cv2
>>> image = cv2.imread('foo.jpg')
>>> print image.shape
 (184, 300, 3)
>>> gray_image = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
>>> print gray_image.shape 
 (184, 300)
>>> cv2.imwrite('gray.jpg', gray_image)