pil example RBG histogram (snippet)

Python pil example 'RBG histogram'

Modules used in program:

• import math
• import matplotlib.pyplot as plt

python RBG histogram

Python pil example: RBG histogram

from PIL import Image
import matplotlib.pyplot as plt
import math 
# image on which histogram is to be plotted 
img = Image.open("nature.jpg") 
pixels = img.load()
# for storing key values 
# key is the pixel intensity 
# values are the number of pixels 
redMap = {}                         # for red
greenMap = {}                         # for green
blueMap = {}                        # for blue
for i in range(img.size[0]):
    for j in range(img.size[1]):
        r, g, b = pixels[i, j][0], pixels[i, j][1], pixels[i, j][2];
        if redMap.get(r) == None:
            redMap[r] = 1;
        else:
            redMap[r] = redMap.get(r)+1;
        if greenMap.get(g) == None:
            greenMap[g] = 1;
        else:
            greenMap[g] = greenMap.get(g)+1;
        if blueMap.get(b) == None:
            blueMap[b] = 1;
        else:
            blueMap[b] = blueMap.get(b)+1;
plt.bar(list(redMap.keys()), redMap.values(), color='r')
plt.show()
plt.bar(list(greenMap.keys()), greenMap.values(), color='g')
plt.show()
plt.bar(list(blueMap.keys()), blueMap.values(), color='b')
plt.show()

Python links

• Learn Python: https://pythonbasics.org/
• Python Tutorial: https://pythonprogramminglanguage.com