how to get 'mean' and 'std' of isic18?

[DumbGuy-AI]

class myNormalize:
def init(self, data_name, train=True):
if data_name == 'isic18':
if train:
self.mean = 157.561
self.std = 26.706
else:
self.mean = 149.034
self.std = 32.022
I wonder to konw how to calculate maen and std with specific code.I need some help,plz.

[JCruan519]

import numpy as np
import cv2
import os
 
def calculate_means_vars(img_datasets_path, img_h=224, img_w=224):
    means, stdevs = [], []
    img_list = []
    imgs_path_list = os.listdir(img_datasets_path)
 
    len_ = len(imgs_path_list)
    i = 0
    for item in imgs_path_list:
        img = cv2.imread(os.path.join(imgs_path,item))
        img = cv2.resize(img,(img_w,img_h))
        img = img[:, :, :, np.newaxis]
        img_list.append(img)
        i += 1 

    imgs = np.concatenate(img_list, axis=3)
    imgs = imgs.astype(np.float32) / 255.
 
    for i in range(3):
        pixels = imgs[:, :, i, :].ravel()  # 拉成一行
        means.append(np.mean(pixels))
        stdevs.append(np.std(pixels))

    # BGR --> RGB ， CV读取的需要转换，PIL读取的不用转换
    means.reverse()
    stdevs.reverse()
 
    print("normMean = {}".format(means))
    print("normStd = {}".format(stdevs))
    
    return means, stdevs

import os
from PIL import Image
from tqdm import tqdm
import cv2
import numpy as np
img_file_path = '/path/to/images'
images_list = os.listdir(img_file_path)
data_list = []
for i in images_list:
    data_list.append(img_file_path + i)

m_list, s_list = [], []
for img_filename in tqdm(images_list):
    img = cv2.imread(img_file_path + '/' + img_filename)
    m, s = cv2.meanStdDev(img)
    m_list.append(m.reshape((3,)))
    s_list.append(s.reshape((3,)))
m_array = np.array(m_list)
s_array = np.array(s_list)
m = m_array.mean(axis=0, keepdims=True)
s = s_array.mean(axis=0, keepdims=True)
print(m[0][::-1].mean())
print(s[0][::-1].mean())