python mahotas.imread reads a 2d image as 3d

Question

I have an image saved by another code of mine. The image is a normal JPG file. I saved it with imsave.

now when I'm reading it in another code, it seems to be 3d :S

the image is here.

and a simple code to read it is this :

import mahotas

img = mahotas.imread('d:/normal.jpg')
print img.shape, img.dtype

Answer 1

Try reading the jpg as greyscale like this:

mahotas.imread('d:/normal.jpg', as_grey = True)

Answer 2

(Author of mahotas here).

The suggestion by Junuxx is correct:

mahotas.imread('file.jpg', as_grey=True)

This reads the RGB file and converts it to grey scale by a weighted average of the components (they are not equally weighted, but use typical coefficients that attempt to be perceptually more accurate).

The alternative (which I rather prefer) is:

im = mahotas.imread('file.jpg')
im = im[:,:,0]

I assume that all the channels have the same values and just use the first one.