python-opencv(3)图像类型转换

#图像类型转换
import cv2
img1 = cv2.imread(r"C:\Users\lihuanyu\Desktop\opencv\image\lenacolor.png")
cv2.imshow("origial",img1) 
b,g,r = cv2.split(img1)
img2 = cv2.cvtColor(img1,cv2.COLOR_BGR2GRAY)
img3 = cv2.cvtColor(img1,cv2.COLOR_BGR2RGB)
img4 = cv2.cvtColor(img2,cv2.COLOR_GRAY2BGR)
print(img2.shape)
cv2.imshow("gray",img2)
cv2.imshow("rgb",img3)
cv2.imshow("img4",img4)
cv2.waitKey()
cv2.destroyAllWindows()