Python: Read and write TIFF 16 bit , three channel , colour images

Question

Does anyone have a method for importing a 16 bit per channel, 3 channel TIFF image in Python?

I have yet to find a method which will preserve the 16 bit depth per channel when dealing with the TIFF format. I am hoping that some helpful soul will have a solution.

Here is a list of what I have tried so far without success and the results:

import numpy as np
import PIL.Image as Image
import libtiff
import cv2

im = Image.open('a.tif')
# IOError: cannot identify image file

tif = libtiff.TIFF.open('a.tif')
im = tif.read_image()
# im only contains one of the three channels. im.dtype is uint16 as desired.
im = []
for i in tif.iter_images():
    # still only returns one channel

im = np.array(cv2.imread('a.tif'))
# im.dtype is uint8 and not uint16 as desired.
# specifying dtype as uint16 does not correct this

So far the only solution I have found is to convert the image to PNG with ImageMagick. Then the bog standard matplotlib.pyplot.imread reads the PNG file without any problems.

Another problem I have is saving any numpy arrays as 16 bit PNG files which so far has not been straightforward either.

Answer 1

It has limited functionality, especially when it comes to writing back to disk non RGB images, but Christoph Gohlke's tifffile module reads in 3 channel 16-bit TIFFs with no problems, I just tested it:

>>> import tifffile as tiff
>>> a = tiff.imread('Untitled-1.tif')
>>> a.shape
(100L, 100L, 3L)
>>> a.dtype
dtype('uint16')

And Photoshop reads without complaining what I get from doing:

>>> tiff.imsave('new.tiff', a)