Plot picture in RGB, CNY and black & white

import numpy as np

import matplotlib.pyplot as plt

import matplotlib.image as npimage

def redFilter(img_orig):

    im = np.copy(img_orig) # On fait une copie de l'original

    for i in range(im.shape[0]):

        for j in range(im.shape[1]):

            r, v, b, a = im[i, j]

            im[i, j] = (r,0,0,a)

    return im

def blueFilter(img_orig):

    im = np.copy(img_orig) # On fait une copie de l'original

    for i in range(im.shape[0]):

        for j in range(im.shape[1]):

            r, v, b, a = im[i, j]

            im[i, j] = (0,0,b,a)

    return im

def greenFilter(img_orig):

    im = np.copy(img_orig) # On fait une copie de l'original

    for i in range(im.shape[0]):

        for j in range(im.shape[1]):

            r, v, b, a = im[i, j]

            im[i, j] = (0, v, 0, a)

    return im

def cyanFilter(img_orig):

    im = np.copy(img_orig) # On fait une copie de l'original

    for i in range(im.shape[0]):

        for j in range(im.shape[1]):

            r, v, b, a = im[i, j]

            im[i, j] = (r, 1, 1, a)

    return im

def magentaFilter(img_orig):

    im = np.copy(img_orig) # On fait une copie de l'original

    for i in range(im.shape[0]):

        for j in range(im.shape[1]):

            r, v, b, a = im[i, j]

            im[i, j] = (1, v, 1, a)

    return im

def yellowFilter(img_orig):

    im = np.copy(img_orig) # On fait une copie de l'original

    for i in range(im.shape[0]):

        for j in range(im.shape[1]):

            r, v, b, a = im[i, j]

            im[i, j] = (1, 1, b, a)

    return im

def blackFilter(img_orig):

    im = yellowFilter(img_orig) # On fait une copie de l'original

    for i in range(im.shape[0]):

        for j in range(im.shape[1]):

            r, v, b, a = im[i, j]

            y = 0.299*r + 0.587*v  + 0.114*b

            im[i, j] = (y, y, y, a)

    return im

#Lecture de l'image

img = npimage.imread("res/lemon.png")

#Plot RGB

plt.subplot(221)

imgplot = plt.imshow(img)

plt.subplot(222)

imgplot = plt.imshow(redFilter(img))

plt.subplot(223)

imgplot = plt.imshow(greenFilter(img))

plt.subplot(224)

imgplot = plt.imshow(blueFilter(img))

plt.show()    

#Plot CNY

plt.subplot(221)

imgplot = plt.imshow(img)

plt.subplot(222)

imgplot = plt.imshow(cyanFilter(img))

plt.subplot(223)

imgplot = plt.imshow(magentaFilter(img))

plt.subplot(224)

imgplot = plt.imshow(yellowFilter(img))

plt.show()

#Plot black & white

imgplot = plt.imshow(blackFilter(img))

plt.show()