画像のプロパティとピクセル値を参照してください

画像の属性とピクセル値を参照してください

import cv2

img1 = cv2.imread('cat.bmp', cv2.IMREAD_GRAYSCALE)
img2 = cv2.imread('cat.bmp', cv2.IMREAD_COLOR)

img1 = cv2.imread('cat.bmp', cv2.IMREAD_GRAYSCALE)
img2 = cv2.imread('cat.bmp', cv2.IMREAD_COLOR)

print('type(img1):', type(img1)) # type(img1): <class 'numpy.ndarray'>
print('img1.shape:', img1.shape) # img1.shape: (480, 640)
print('img2.shape:', img2.shape) # img2.shape: (480, 640, 3)
print('img2.dtype:', img2.dtype) # img2.dtype: uint8

h, w = img2.shape[:2] # h: 480, w: 640
print('img2 size: {} x {}'.format(w, h))

if len(img1.shape) == 2:
	print('img1 is a grayscale image')
elif len(img1.shape) == 3:
	print('img1 is a truecolor image')

img1 = cv2.imread('cat.bmp', cv2.IMREAD_GRAYSCALE)
img2 = cv2.imread('cat.bmp', cv2.IMREAD_COLOR)

for y in range(h):
	for x in range(w):
		img1[y, x] = 255
		img2[y, x] = [0, 0, 255]
# img1[:,:] = 255
# img2[:,:] = (0, 0, 255)