要求

存在一个文件夹内有若干张图像，需要计算每张图片的RGB均值，并计算全部图像的RGB均值。

代码

# -*- 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)

这里需要注意cv2.imread()读取顺序为BGR问题。

注意

路径不能出现中文，不然容易出错。

错误如下：

TypeError: ‘NoneType’ object is not subscriptable

结果

补充知识：Image得到图片像素的RGB

我就废话不多说了，大家还是直接看代码吧！

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()  

打印结果

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