python - Python中RAW图像的JPEG解压缩

Question

当我尝试对 RAW 数据进行 JPEG 解压缩(旧式 JPEG 压缩，不是 JPEG-LS 也不是 JPEG2000)时，出现以下错误:

Traceback (most recent call last):
  File "raw-reader.py", line 766, in <module>
    raw_image_data = imageio.imread(io.BytesIO(raw_packed_image_data))
  File "/home/ian/.local/lib/python3.6/site-packages/imageio/core/functions.py", line 206, in imread
    reader = read(uri, format, 'i', **kwargs)
  File "/home/ian/.local/lib/python3.6/site-packages/imageio/core/functions.py", line 129, in get_reader
    return format.get_reader(request)
  File "/home/ian/.local/lib/python3.6/site-packages/imageio/core/format.py", line 168, in get_reader
    return self.Reader(self, request)
  File "/home/ian/.local/lib/python3.6/site-packages/imageio/core/format.py", line 217, in __init__
    self._open(**self.request.kwargs.copy())
  File "/home/ian/.local/lib/python3.6/site-packages/imageio/plugins/pillow.py", line 398, in _open
    pilmode=pilmode, as_gray=as_gray)
  File "/home/ian/.local/lib/python3.6/site-packages/imageio/plugins/pillow.py", line 122, in _open
    self._im = factory(self._fp, '')
  File "/home/ian/.local/lib/python3.6/site-packages/PIL/JpegImagePlugin.py", line 780, in jpeg_factory
    im = JpegImageFile(fp, filename)
  File "/home/ian/.local/lib/python3.6/site-packages/PIL/ImageFile.py", line 102, in __init__
    self._open()
  File "/home/ian/.local/lib/python3.6/site-packages/PIL/JpegImagePlugin.py", line 339, in _open
    handler(self, i)
  File "/home/ian/.local/lib/python3.6/site-packages/PIL/JpegImagePlugin.py", line 166, in SOF
    raise SyntaxError("cannot handle %d-bit layers" % self.bits)
SyntaxError: cannot handle 14-bit layers

图像中的RAW数据是14位JPEG数据，imageio无法读取它。当我尝试使用 Pillow 时，它甚至无法将数据识别为 JPEG。我现在的问题是:如何在不编写自己的 JPEG 解压缩器的情况下解压缩数据，同时记住数据是 14 位？

我的代码:

import io
import imageio

allbytes = open("raw_data.dat", "rb").read()

raw_packed_image_data = allbytes
raw_image_data = imageio.imread(io.BytesIO(raw_packed_image_data))

文件raw_data.dat是一个纯粹包含用JPEG压缩的RAW图像数据的文件。链接至raw_data.dat

Answer 1

raw_data.dat 是一个 JPEG 无损、非分层 文件，具有 2 帧且精度 > 8 位，是一种非常罕见的格式。

imagecodecs包可以读取该文件(假设存在 _imagecodecs Cython 扩展):

>>> from imagecodecs import jpegsof3_decode
>>> data = open('raw_data.dat', 'rb').read()
>>> image = jpegsof3_decode(data)
>>> image.shape
(3528, 2640, 2)
>>> image.dtype
dtype('uint16')

LEADTOOLS SDK 也应该能够读取该文件(未测试)。