How can I convert an RGB image into grayscale in Python?

Question

I\'m trying to use matplotlib to read in an RGB image and convert it to grayscale.

In matlab I use this:

img = rgb2gray(imread(\'image.p         


        

Answer 1

Using this formula

Y' = 0.299 R + 0.587 G + 0.114 B 

We can do

import imageio
import numpy as np
import matplotlib.pyplot as plt

pic = imageio.imread('(image)')
gray = lambda rgb : np.dot(rgb[... , :3] , [0.299 , 0.587, 0.114]) 
gray = gray(pic)  
plt.imshow(gray, cmap = plt.get_cmap(name = 'gray'))

However, the GIMP converting color to grayscale image software has three algorithms to do the task.