python：只想在opencv中显示红色通道

Question

我是图像处理的初学者。我在许多颜色空间中显示图像，下面的代码显示 3 通道 R G B 中的图像，但是图像以灰色布局显示。我需要显示三个图像，一个红色通道为红色图像，另一个为蓝色，最后一个为绿色。提前致谢。

# cspace.py
import cv2
import numpy as np

image = cv2.imread('download.jpg')

# Convert BGR to HSV
hsv = cv2.cvtColor(image, cv2.COLOR_BGR2HSV)
hsl = cv2.cvtColor(image, cv2.COLOR_BGR2HLS) # equal to HSL
luv = cv2.cvtColor(image, cv2.COLOR_BGR2LUV)


#RGB - Blue
cv2.imshow('B-RGB.jpg',image[:, :, 0])
cv2.imwrite('B-RGB.jpg',image[:, :, 0])

# RGB - Green
cv2.imshow('G-RGB',image[:, :, 1])
cv2.imwrite('G-RGB.jpg',image[:, :, 1])

# RGB Red
cv2.imshow('R-RGB',image[:, :, 2])
cv2.imwrite('R-RGB.jpg',image[:, :, 2])


cv2.waitKey(0)

Blue image as displayed currently

i need to display blue channel like this image

Answer 1

您可以只复制原始图像并将一些通道设置为 0。

import cv2

image = cv2.imread('download.jpg')

b = image.copy()
# set green and red channels to 0
b[:, :, 1] = 0
b[:, :, 2] = 0


g = image.copy()
# set blue and red channels to 0
g[:, :, 0] = 0
g[:, :, 2] = 0

r = image.copy()
# set blue and green channels to 0
r[:, :, 0] = 0
r[:, :, 1] = 0


# RGB - Blue
cv2.imshow('B-RGB', b)

# RGB - Green
cv2.imshow('G-RGB', g)

# RGB - Red
cv2.imshow('R-RGB', r)

cv2.waitKey(0)

Answer 2

import cv2
import numpy as np

channel_initials = list('BGR')

image = cv2.imread('download.jpg')

for channel_index in range(3):
    channel = np.zeros(shape=image.shape, dtype=np.uint8)
    channel[:,:,channel_index] = image[:,:,channel_index]
    cv2.imshow(f'{channel_initials[channel_index]}-RGB', channel)
cv2.waitKey(0)