改善从映像复制字节

Question

I have the following minimal code that gets the bytes from an image:

import Image

im = Image.open("kitten.png")
im_data = [pix for pixdata in im.getdata() for pix in pixdata]

This is rather slow (I have gigabytes of images to process) so how could this be sped up? I'm also unfamiliar with what exactly that code is trying to do. All my data is 1280 x 960 x 8-bit RGB, so I can ignore corner cases, etc.

(FYI, the full code is here - I've already replaced the ImageFile loop with the above Image.open() .)

Answer 1

你可以试试

scipy.ndimage.imread()

Answer 2

If you mean speeding up by algorythamically i can suggest you accessing file with multiple threads simultaneously (only if you don't have a connection between processing sequence)

divide file logically by few sections and access each part simultaneously with threads (you have to put your operation inside a function and call it with threads)

here is a link to tutorial about threading in python

threding in python

Answer 3

I solved my problem, I think:

>>> [pix for pixdata in im.getdata() for pix in pixdata] ==
           numpy.ndarray.tolist(numpy.ndarray.flatten(numpy.asarray(im)))
True

This cuts down the runtime by half, and with a bit of bash magic I can run the conversion on the 56 directories in parallel.