Convert from PNG image to ASCII flag (0/1) file

png2flag.py

import numpy as np
import matplotlib.image as mpimg

def rgb2gray(rgb):
    ''' Convert rgb to gray '''
    return np.dot(rgb[...,:3], [0.299, 0.587, 0.114])

def gray2bin(gray):
     ''' Convert gray to binary (0,1)'''
     #return (gray>0.5).astype('uint8') 
     return (gray<0.5).astype('uint8') 

fname = 'cylinder_simple2'

img = mpimg.imread(fname+'.png')
np.savetxt(fname+'.dat', gray2bin(rgb2gray(img)), fmt="%d")