matplotlib-users

[Matplotlib-users] importing images

[Rein v. d. B. (UvA) <re...@sc...>]

What is the prefered way to read in images in numarray/matplotlib?

I know of PIL but it seems like a lot of overlap with numarray just to read an 
image from file.

I really need to read only one type of file (say ppm) and then i can use 
imagemagick to convert from and to that format.

Regards
Rein

Re: [Matplotlib-users] importing images

[John H. <jdh...@ac...>]

>>>>> "Rein" == Rein van den Boomgaard (UvA) <re...@sc...> writes:

    Rein> What is the prefered way to read in images in
    Rein> numarray/matplotlib?

No good way, currently.  I plan to add a PNG loader in the near
future.  Would this suffice for you?  What do you think are the core
set of image formats that matplotlib should support? ... the fewer the
better!

    Rein> I know of PIL but it seems like a lot of overlap with
    Rein> numarray just to read an image from file.

True, but for the record, here is the recipe I use to do the PIL ->
numerix conversion


import Image
from matplotlib.matlab import *

im = Image.open('../data/leo_ratner.jpg')
s = im.tostring()    # convert PIL image -> string

# convert string -> numerix array of floats
rgb = fromstring(s, UInt8).astype(Float)/255.0  

# resize to RGB array
rgb = resize(rgb, (im.size[1], im.size[0], 3))

imshow(rgb, interpolation='nearest')
axis('off')  # don't display the image axis
show()