numpy with python: convert 3d array to 2d

Question

Say that I have a color image, and naturally this will be represented by a 3-dimensional array in python, say of shape (n x m x 3) and call it img.

I want a new 2-d

Answer 1

If you have the scikit module installed, then you can use the rgb2grey (or rgb2gray) to make a photo from color to gray (from 3D to 2D)

from skimage import io, color

lina_color = io.imread(path+img)
lina_gray = color.rgb2gray(lina_color)

In [33]: lina_color.shape
Out[33]: (1920, 1280, 3)

In [34]: lina_gray.shape
Out[34]: (1920, 1280)