最近在跑代码的时候，需要用到RGB三个通道上的均值，如下图所示：

写了一个程序，如下：

import os

import cv2

import random

import numpy as np

#数据集的位置

dataset_dir = 'data'

# 验证集图像数量

_NUM_VALIDATION = 1000

# 随机种子

_RANDOM_SEED = 0

def _get_filenames_and_classes(dataset_dir):

  """Returns a list of filenames and inferred class names.

  Args:

	dataset_dir:A directory containing a set of different datasets.Each dataset

	contains a set of subdirectories representing class names.Each subdirectory

	should contain PNG or JPG encoded images.

  Returns:

    A list of image file paths, relative to `dataset_dir` and the list of

    subdirectories, representing class names.

  """

  flower_root = os.path.join(dataset_dir, 'Stripe')

  directories = []

  class_names = []

  for filename in os.listdir(flower_root):

    path = os.path.join(flower_root, filename)

    if os.path.isdir(path):

      directories.append(path)

      class_names.append(filename)

  photo_filenames = []

  for directory in directories:

    for filename in os.listdir(directory):

      path = os.path.join(directory, filename)

      photo_filenames.append(path)

      # Divide into train and test:

  random.seed(_RANDOM_SEED)

  random.shuffle(photo_filenames)

  training_filenames = photo_filenames[_NUM_VALIDATION:]

  #validation_filenames = photo_filenames[:_NUM_VALIDATION]

  return training_filenames

def compute(file_names):

    per_image_Rmean = []

    per_image_Gmean = []

    per_image_Bmean = []

    for file_name in file_names:

        img = cv2.imread(file_name, 1)

        per_image_Rmean.append(np.mean(img[:,:,0]))

        per_image_Gmean.append(np.mean(img[:,:,1]))

        per_image_Bmean.append(np.mean(img[:,:,2]))

    R_mean = np.mean(per_image_Rmean)

    G_mean = np.mean(per_image_Gmean)

    B_mean = np.mean(per_image_Bmean)

    return R_mean, G_mean, B_mean

if __name__ == '__main__':

    photo_filenames = _get_filenames_and_classes(dataset_dir)

    R, G, B= compute(photo_filenames)

    print(R, G ,B)

注释：

目录结构如下所示：

data（放数据集的地方）

        cifar10（数据集）

            airplane

            .....

        Stripe（数据集）

            defect

            normal