On 12 March 2013 13:28, Robert Flintham <robert.flint...@uhb.nhs.uk> wrote:
> Sorry, the subject line was for a related question that I decided not to ask,
> I forgot to change it when I changed my email. I've changed it now!
>
> I'm using Python 3.3 on Windows with the pydicom module
> (http://code.google.com/p/pydicom/). Using pydicom, I've ended up with a
> "bytes" object of length (512*512/8 = 32768) containing a 512x512 1-bit
> bitmap (i.e. each byte represents 8 pixels of either 1 or 0). When I print
> this to screen I get:
> 'b\x00\x00\x00.....'
>
> I can unpack this to a tuple of the integer representations of binary data,
> but that doesn't really help as presume I need the binary (8 digit)
> representation to be able to translate that into an image.
>
> I wasn't sure which GUI library to use, so haven't specified one. As it's
> Python 3, Tkinter is available. I also have matplotlib and numpy installed,
> and PIL.
>
> Ideally, I'd like to be able to access the pixel data in the form of a numpy
> array so that I can perform image-processing tasks on the data.
>
> So now that I've explained myself slightly more fully, does anyone have any
> thoughts on how to do this?
Numpy and matplotlib will do what you want:
import numpy as np
import matplotlib.pyplot as plt
def bits_to_ndarray(bits, shape):
abytes = np.frombuffer(bits, dtype=np.uint8)
abits = np.zeros(8 * len(abytes), np.uint8)
for n in range(8):
abits[n::8] = (abytes % (2 ** (n+1))) != 0
return abits.reshape(shape)
# 8x8 image = 64 bits bytes object
bits = b'\x00\xff' * 4
img = bits_to_ndarray(bits, shape=(8, 8))
plt.imshow(img)
plt.show()
Oscar
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