Mean_Std/mean_std.py at master · whywhs/Mean_Std · GitHub

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import os
from PIL import Image
import matplotlib.pyplot as plt
import numpy as np
from scipy.misc import imread

filepath = '/data' # the path of dataset
pathDir = os.listdir(filepath)

R_channel = 0
G_channel = 0
B_channel = 0
img_size = 0

for idx in range(len(pathDir)):
    filename = pathDir[idx]
    img = imread(os.path.join(filepath, filename))
    img = img/255.0
    img_size = img_size + img.shape[0]*img.shape[1]
    R_channel = R_channel + np.sum(img[:,:,0])
    G_channel = G_channel + np.sum(img[:,:,1])
    B_channel = B_channel + np.sum(img[:,:,2])

R_mean = R_channel / img_size
G_mean = G_channel / img_size
B_mean = B_channel / img_size

R_channel = 0
G_channel = 0
B_channel = 0
for idx in range(len(pathDir)):
    filename = pathDir[idx]
    img = imread(os.path.join(filepath, filename))
    img = img/255.0
    R_channel = R_channel + np.sum((img[:,:,0] - R_mean)**2)
    G_channel = G_channel + np.sum((img[:,:,1] - G_mean)**2)
    B_channel = B_channel + np.sum((img[:,:,2] - B_mean)**2)

R_var = (R_channel / img_size)**0.5
G_var = (G_channel / img_size)**0.5
B_var = (B_channel / img_size)**0.5

print("R_mean is %f, G_mean is %f, B_mean is %f" % (R_mean, G_mean, B_mean))
print("R_var is %f, G_var is %f, B_var is %f" % (R_var, G_var, B_var))