Question

I’m trying to add all the .tiff files in a directory together using ImageChops, but I keep on getting the error ‘IOError: cannot identify image file’. I thought it was just a problem with trying to use a file path instead of an image object, but similar codes in other places don’t have this problem.

def imadd():  #subcommand
    img1=Image.new('RGB',(2048, 2048))
    img1.save("summation.tif")
    for file in os.listdir(directoryname):
        if fnmatch.fnmatch(file, '*.tif'):
           im2 = Image.open("summation.tif", mode='r')
           im3 = Image.open(os.path.join(directoryname, file))
           finalimg = ImageChops.add(im2, im3, 1, 0)
           finalimg.save("summation.tif") 

By trail and error, all the parts work except:

im3 = Image.open(os.path.join(directoryname, file)).

I also tried using glob.glob(), but that still returns the same error.

Answer 1

While you can open and show 16 bit tiffs with PIL, ImageChops doesn’t work. matplotlib and scipy have many more tools available.

Also im3 = Image.open(os.path.join(directoryname, file)) needs to be Image.open(unicode(os.path.join(directoryname, file)))