将内存中的OpenCV映像写入BytesIO或Tempfile [英] Write OpenCV image in memory to BytesIO or Tempfile

问题描述

我需要将内存中的OpenCV映像写入BytesIO或Tempfile对象，以供其他地方使用.

I need to write an OpenCV image that sits in memory to a BytesIO or Tempfile object for use elsewhere.

我担心这是一个死胡同的问题，因为cv2.imwrite()将文件名作为参数，然后使用文件扩展名来推断要写入的图像类型(.jpg，.png，.tiff，等等.). cv2.imwrite()在C ++级别执行此操作，因此我担心无法成功将非文件名对象传递给它.

I am concerned this is a dead end question, because cv2.imwrite() takes a filename as an argument, and then uses the file extension to infer the image type to write (.jpg, .png, .tiff, etc.). cv2.imwrite() does this at the C++ level, so I am concerned that there is no way to successfully pass a non-filename object to it.

另一种可能的解决方案是通过numpy转换为PIL，该功能可以写入BytesIO和Tempfile对象，但我想避免不必要的复制.

The other possible solution is converting to PIL through numpy, which has the capacity to write to BytesIO and Tempfile objects, but I want to avoid needless copies.

推荐答案

cv2.imencode可能会帮助您:

import numpy as np
import cv2
import io

img = np.ones((100, 100), np.uint8)
# encode
is_success, buffer = cv2.imencode(".jpg", img)
io_buf = io.BytesIO(buffer)
# decode
decode_img = cv2.imdecode(np.frombuffer(io_buf.getbuffer(), np.uint8), -1)
print(np.allclose(img, decode_img))   # True

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