python 实现单通道转3通道

import numpy as np
a=np.asarray([[10,20],[101,201]])

# a=a[:,:,np.newaxis]
# print(a.shape)
# b= a.repeat([3],axis=2)
# print(b.shape,b)

image = np.expand_dims(a, axis=2)
image = np.concatenate((image, image, image), axis=-1)

print(image)

axis=-1就是最后一个通道