图像类型转换代码

Vic Woo May 23, 2023

OpenCV（Numpy）与PIL互转

img_pil转img_np

from PIL import Image
import numpy as np
img_pil = Image.open("./test.png")

img_np = np.array(img_pil)

img_np转img_pil

from PIL import Image
import numpy as np
 
# 生成一个随机数组
# randint()生成一定范围的数组
# random()生成0-1之间的均匀分布
# randn() 生成高斯分布
img_np=np.random.randint(0,255,(48,48))
 
img_pil = Image.fromarray(img_np)

OpenCV（Numpy）与Base64互转

img_np转img_base64

def imgNP_to_imgBase64(img_np):
    """
    convert img_np to img_base64
    """
    img_bytes = cv2.imencode('.jpg', img_np)[1].tobytes() #将图片编码成流数据，放到内存缓存中，然后转化成byte格式
    img_base64 = base64.b64encode(img_bytes) # 编码为base64
    # 将byte格式的Base64编码转换成utf-8字符串
    # img_base64_string = img_base64.decode('utf-8') # or img_base64_string = str(img_base64, encoding="utf8")
    return img_base64

img_base64转img_np

def imgBase64_to_imgNP(img_base64):
    """
    convert img_base64 to img_np
    """
    img_bytes = base64.b64decode(img_base64) # 该输入同样适配Base64的utf-8字符串img_base64_string
    nparr = np.frombuffer(img_bytes, dtype=np.uint8)
    img_np = cv2.imdecode(nparr, cv2.IMREAD_COLOR)
    return img_np

直接读图转成Base64的utf-8字符串并重新存图

with open(img_path, 'rb') as jpg_file:
    img_bytes = jpg_file.read()
img_base64 = base64.b64encode(img_bytes)
img_base64_string = img_base64.decode('utf-8')
# 将 base64 字符串解码成图片字节码
img_bytes = base64.b64decode(img_base64_string)
# 将字节码以二进制形式存入图片文件中，注意 'wb'
with open(img_path, 'wb') as jpg_file:
    jpg_file.write(img_bytes)

PIL与Base64互转

img_pil转img_base64

from PIL import Image
import io
import base64

img_pil = Image.open('image.jpg')
# 创建一个BytesIO对象，用于临时存储图像数据
img_bytesIO = io.BytesIO()
# 将图像保存到BytesIO对象中，格式为JPEG
img_pil.save(img_bytesIO, format='JPEG')
# 将BytesIO对象的内容转换为字节串
img_bytes = img_bytesIO.getvalue()
# 将图像数据编码为Base64字符串
img_base64_string = base64.b64encode(img_bytes).decode('utf-8')

img_base64转img_pil

from io import BytesIO
import base64
from PIL import Image

def imgBase64_to_imgPil(img_base64_string: str) -> Image.Image:
    img_bytes = base64.b64decode(img_base64_string)
    img_bytesIO = BytesIO(img_bytes)
    img_pil = Image.open(img_bytesIO)
    return img_pil

# 或者一行代码表示
img_pil = Image.open(BytesIO(base64.b64decode(img_base64_string))).convert("RGB")