How to count number of white and black pixels in color picture in python? How to count total pixels using numpy

Question

I want to calculate persentage of black pixels and white pixels for the picture, its colorful one

import numpy as np
import matplotlib.pyplot as plt

image = cv2         


        

Answer 1

You can use the getcolors() function from PIL image, this function return a list of tuples with colors found in image and the amount of each one. I'm using the following function to return a dictionary with color as key, and counter as value.

from PIL import Image

def getcolordict(im):
    w,h = im.size
    colors = im.getcolors(w*h)
    colordict = { x[1]:x[0] for x in colors }
    return colordict

im = Image.open('image.jpg')
colordict = getcolordict(im)

# get the amount of black pixels in image
# in RGB black is 0,0,0
blackpx = colordict.get((0,0,0))

# get the amount of white pixels in image
# in RGB white is 255,255,255
whitepx = colordict.get((255,255,255))  

# percentage
w,h = im.size
totalpx = w*h
whitepercent=(whitepx/totalpx)*100
blackpercent=(blackpx/totalpx)*100