Question

I have a .jpg image that I would like to convert to Python array, because I implemented treatment routines handling plain Python arrays.

It seems that PIL images support conversion to numpy array, and according to the documentation I have written this:

from PIL import Image
im = Image.open("D:\Prototype\Bikesgray.jpg")
im.show()

print(list(np.asarray(im)))

This is returning a list of numpy arrays. Also, I tried with

list([list(x) for x in np.asarray(im)])

which is returning nothing at all since it is failing.

How can I convert from PIL to array, or simply from numpy array to Python array?

Answer 1

I think what you are looking for is:

list(im.getdata())

or, if the image is too big to load entirely into memory, so something like that:

for pixel in iter(im.getdata()):
    print pixel

from PIL documentation:

getdata

im.getdata() => sequence

Returns the contents of an image as a sequence object containing pixel
values. The sequence object is flattened, so that values for line one
follow directly after the values of line zero, and so on.

Note that the sequence object returned by this method is an internal
PIL data type, which only supports certain sequence operations,
including iteration and basic sequence access. To convert it to an
ordinary sequence (e.g. for printing), use list(im.getdata()).