图像类型转换

转换方式其实有两百多种 重点介绍这三种~~:彩色转灰度，BGR转RGB，灰度转BGR~~

1，彩色转灰度
b=cv2.cvtColor(a,cv2.COLOR_BGR2GRAY)

import cv2
import numpy as np
a=cv2.imread('F:\\Pycharm Project\\image\\lenacolor.jpg',cv2.IMREAD_UNCHANGED)
b=cv2.cvtColor(a,cv2.COLOR_BGR2GRAY)
cv2.imshow('a',a)
cv2.imshow('b',b)
cv2.waitKey()
cv2.destroyAllWindows()

2.BGR转RGB
b=cv2.cvtColor(a,cv2.COLOR_BGR2RGB)

import cv2
import numpy as np
a=cv2.imread('F:\\Pycharm Project\\image\\lenacolor.jpg',cv2.IMREAD_UNCHANGED)
b=cv2.cvtColor(a,cv2.COLOR_BGR2RGB)
cv2.imshow('original',a)
cv2.imshow('RGB',b)
cv2.waitKey()
cv2.destroyAllWindows()

3.灰度转BGR

import cv2
import numpy as np
a=cv2.imread('F:\\Pycharm Project\\image\\lena256.bmp',cv2.IMREAD_UNCHANGED)
b=cv2.cvtColor(a,cv2.COLOR_GRAY2BGR)
cv2.imshow('original',a)
cv2.imshow('BGR',b)
cv2.waitKey()
cv2.destroyAllWindows()

我们可以看出 ，灰度转BGR图看似没有什么区别 并没有变成彩色图片 那我们来看看区别在哪里

import cv2
import numpy as np
a=cv2.imread('F:\\Pycharm Project\\image\\lena256.bmp',cv2.IMREAD_UNCHANGED)
b=cv2.cvtColor(a,cv2.COLOR_GRAY2BGR)
print(a.shape)
print(b.shape)
bb,bg,br=cv2.split(b)
cv2.imshow('bb',bb)
cv2.imshow('bg',bg)
cv2.imshow('br',br)
cv2.waitKey()
cv2.destroyAllWindows()

运行结果