# -*- coding: utf-8 -*-
"""
Created on Thu Nov 1 10:43:29 2018
@author: Administrator
"""
import os
import cv2
import numpy as np
 
path = 'C:/Users/Administrator/Desktop/rgb'
def compute(path):
  file_names = os.listdir(path)
  per_image_Rmean = []
  per_image_Gmean = []
  per_image_Bmean = []
  for file_name in file_names:
    img = cv2.imread(os.path.join(path, file_name), 1)
    per_image_Bmean.append(np.mean(img[:,:,0]))
    per_image_Gmean.append(np.mean(img[:,:,1]))
    per_image_Rmean.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__':
  R, G, B= compute(path)
  print(R, G ,B)

from PIL import Image
image = Image.open('./3.png')
print(image)#查看mode是否等于RGB,
image_rgb = image.convert("RGB")
image_rgb.getcolors()  

<PIL.PngImagePlugin.PngImageFile image mode=P size=500x332 at 0x7F53383FADA0>

[(10990, (192, 0, 128)),#10990表示像素总数，(192, 0, 128)表示RGB值
 (7589, (224, 224, 192)),
 (5706, (192, 128, 128)),
 (3913, (0, 64, 0)),
 (137802, (0, 0, 0))]