python PIL、opencv, 二进制、base64 四种图片格式转换

1. 二进制和PIL相互转换

from io import BytesIO
from PIL import Image

with open('picture.jpg', 'rb') as f:
    im = f.read()
# 二进制转PIL
p_img = Image.open(BytesIO(im))   # BytesIO实现了在内存中读写Bytes
print(p_img)  # 输出PIL图片对象
## 输出  ： 

# PIL 转二进制
b_img= BytesIO()   # 创建一个空的Bytes对象
p_img.save(b_img, format='jpeg') # 保存为jpg格式
print(type(b_img)) # 输出 二进制io对象
# 输出：<_io.BytesIO object at 0x00000000047C3288>
b_img= b_img.getvalue()  # 获取图片二进制数据
print(type(b_img))
# 输出  

2. 二进制和cv2转换

import cv2
with open('picture.jpg', 'rb') as f:
	im = f.read()
c_img = cv2.imdecode(numpy.fromstring(im,"uint8"), 1)  # Bytes 转cv2
print(type(c_img))
# 输出 ：

b_img = cv2.imencode('.jpg', c_img)[1].tobytes()       # cv2转Bytes
print(type(b_img))
# 输出 ：

3. PIL和base64转换

import base64
import io
from PIL import Image

with open('picture.jpg', 'rb') as f:
	im = f.read()
# base64转PIL
b64_en_img = base64.b64encode(im)   # base64编码
b64_de_img = base64.b64decode(b64_en_img)  # base64解码
b_io_img = BytesIO(b64_de_img)
p_img = Image.open(b_io_img)
print(p_img)
# 输出： 

# PIL转base64
b_img = BytesIO()
p_img.save(b_img, format='jpeg')
b_img = b_img.getvalue()
b64_img = base64.b64encode(b_img)
# 输出 

4. cv2和base64转换

import base64
import io
import cv2

with open('picture.jpg', 'rb') as f:
	im = f.read()
# base64转cv2
b64_en_img = base64.b64encode(im)   # base64编码
b64_de_img = base64.b64decode(b64_en_img )  # base64解码
np_arr = numpy.fromstring(b64_de_img, numpy.uint8)  # 把字符串转ndarray
c_img = cv2.imdecode(np_arr, cv2.IMREAD_COLOR)
print(type(c_img))
# 输出 

# cv2转base64
b64_img = cv2.imencode('.jpg', c_img)[1].tostring() # 把ndarray转换成字符串
b64_img = base64.b64encode(b64_img)
print(type(b64_img))
# 输出 ：

2. PIL 和opencv转换

import cv2
from PIL import Image
import numpy

# PIL 转 cv2
p_img= Image.open("picture.jpg")
c_img = cv2.cvtColor(numpy.asarray(p_img), cv2.COLOR_RGB2BGR)
print(type(c_img))  # opencv是以ndarray来读取图片的
# 输出： 

# opencv转PIL
c_img = cv2.imread("picture.jpg")
p_img= Image.fromarray(cv2.cvtColor(c_img,cv2.COLOR_BGR2RGB))
print(p_img)
# 输出 ：