[SciPy-user] The IO library and image file formats -- compare with with PIL
Travis E. Oliphant
Mon Apr 21 13:43:12 CDT 2008
Zachary Pincus wrote:
> numpy.fromstring takes a byte sequence and unpacks it into an array of
> a specified shape and data type. Most image file formats are just
> different ways of putting byte sequences on disk and specifying how
> they were compressed, if at all. Most formats have either no
> compression, or LZW/Deflate/zlib-style compression, for which there
> are already python libraries.
> So for example, reading a TIFF file would consist of looking at the
> header to determine the pixel format, image size, and compression,
> then rooting around in the file to assemble the relevant bytes, then
> running that through deflate (most often), and passing the resulting
> string to numpy.fromstring. Same for PNG, or most anything that's not
> JPEG. Writing is similar.
> Again, what I'm imagining wouldn't be a full-featured image IO
> library, but something lightweight with no dependencies outside of
> numpy, and potentially (if JPEG decoding isn't desired), no C-
> extensions. (One could conceivably use numpy to do JPEG encoding and
> decoding, but I've no interest in doing that...)
> This is all just an idea, and I'm not convinced whether it's a great
> idea. But I just wanted to put the suggestion out there...
I've wanted to have native image readers in SciPy for a long time for a
lot of reasons (teaching being one of them so I like this approach).
I'd rather not have a PIL dependency to do such things. But, that is
just my point of view. So, I'm very supportive of this project generally.
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