Small scipy/numpy/pyplot script to clean up a monochrome drawing and show the input and output side by side

cleanup.py

import numpy
from scipy import misc
import matplotlib.pyplot as plt

if __name__ == "__main__":
    input = 'input.png'
    output = 'output.png'
    
    # Editing
    imIn = misc.imread(input)
    imOut = numpy.zeros( (len(imIn), len(imIn[0]), 4), dtype=int )
    i1 = -1
    i2 = -1
    for a in imIn:
        i1 = i1 + 1
        i2 = -1
        for b in a:
            i2 = i2 + 1
            if b[0] < 195:
                #imOut[i1][i2][0] = b[0]
                imOut[i1][i2][0] = 128
                imOut[i1][i2][1] = 0
                imOut[i1][i2][2] = 0
                imOut[i1][i2][3] = 255
            else:
                imOut[i1][i2][0] = 255
                imOut[i1][i2][1] = 255
                imOut[i1][i2][2] = 255
                imOut[i1][i2][3] = 0
    misc.imsave(output, imOut)
    

    # Plotting
    plt.figure()    
    plt.subplot(121)
    # Without reloading the plot
    # will not show the new image.
    plt.imshow(misc.imread(output))
    plt.axis('off')
    rect = plt.figure(1).patch
    rect.set_facecolor('white')    
    plt.subplot(122)
    plt.imshow(imIn)
    plt.axis('off')        
    plt.show()