python opencv rgb转hsv_Python-OpenCV中图像颜色空间转换

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本文主要记录Python-OpenCV中cv2.cvtColor()的使用；

cv2.cvtColor()

转换图像的颜色空间；官方文档

def cvtColor(src, code, dst=None, dstCn=None):

"""

转换图像的颜色空间

Argument:

src: 原图像；

code: 指定颜色空间转换类型；

dst: 目标图像；与原图像大小深度一致；

dstCn: 指定目标图像通道数；默认None，则会根据src、code自动计算；

"""

使用：

#!/usr/bin/env python

#-*- coding:utf-8 -*-

# @Time : 19-4-20 下午3:23

# @Author : chen

"""

opencv读取的图像是BGR格式；

OpenCV可以指定颜色空间转换形式，包括：

RGB与其他颜色空间的转换

BGR与其他颜色空间的转换

"""

import matplotlib.pyplot as plt

import cv2

lena_BGR = cv2.imread("./lena.png")

# show BGR lena

plt.subplot(3, 3, 1)

plt.imshow(lena_BGR)

plt.axis('off')

plt.title('lena_BGR')

# BGR to RGB

lena_RGB = cv2.cvtColor(lena_BGR, cv2.COLOR_BGR2RGB)

plt.subplot(3, 3, 2)

plt.imshow(lena_RGB)

plt.axis('off')

plt.title('lena_RGB')

# BGR to GRAY

lena_GRAY = cv2.cvtColor(lena_BGR, cv2.COLOR_BGR2GRAY)

plt.subplot(3, 3, 3)

plt.imshow(lena_GRAY)

plt.axis('off')

plt.title('lena_GRAY')

# BGR to CIE XYZ

lena_CIEXYZ = cv2.cvtColor(lena_BGR, cv2.COLOR_BGR2XYZ)

plt.subplot(3, 3, 4)

plt.imshow(lena_CIEXYZ)

plt.axis('off')

plt.title('lena_CIEXYZ')

# BGR to YCrCb

lena_YCrCb = cv2.cvtColor(lena_BGR, cv2.COLOR_BGR2YCrCb)

plt.subplot(3, 3, 5)

plt.imshow(lena_YCrCb)

plt.axis('off')

plt.title('lena_YCrCb')

# BGR to HSV

lena_HSV = cv2.cvtColor(lena_BGR, cv2.COLOR_BGR2HSV)

plt.subplot(3, 3, 6)

plt.imshow(lena_HSV)

plt.axis('off')

plt.title('lena_HSV')

# BGR to HLS

lena_HLS = cv2.cvtColor(lena_BGR, cv2.COLOR_BGR2HLS)

plt.subplot(3, 3, 7)

plt.imshow(lena_HLS)

plt.axis('off')

plt.title('lena_HLS')

# BGR to CIE L*a*b

lena_Lab = cv2.cvtColor(lena_BGR, cv2.COLOR_BGR2Lab)

plt.subplot(3, 3, 8)

plt.imshow(lena_Lab)

plt.axis('off')

plt.title('lena_Lab')

# BGR to CIE L*u*v

lena_Luv = cv2.cvtColor(lena_BGR, cv2.COLOR_BGR2Luv)

plt.subplot(3, 3, 9)

plt.imshow(lena_Luv)

plt.axis('off')

plt.title('lena_Luv')

plt.show()

1. RGB to GRAY

RGB to GRAY: $$ Y = 0.299 \cdot R + 0.587 \cdot G + 0.114\cdot B $$ GRAY to RGB: $$ R = Y, \ G=Y, \ B = Y, \ A = max(ChannelRange) $$

2. RGB to CIE XYZ

3. RGB to YCrCb JPEG

4. RGB to HSV

5. RGB to HLS

6. RGB to CIE L*a*b

7. RGB to CIE L*u*v