# -*- coding: utf-8 -*-
import cv2, matplotlib
import numpy as np
import matplotlib.pyplot as plt
pixel=cv2.imread('2.jpg')
print 'pixel=',pixel
average_img = np.average(pixel, axis=0)
print 'average_img=',average_img
average_img_weights = np.average(pixel, axis=0,weights=[1./4,2,2]) # pixel 3X3
print 'average_img_weights=',average_img_weights
average_color = np.average(average_img, axis=0)
average_color = np.uint8(average_color)
print 'average_color=',average_color 
average_color_img = np.array([[average_color]*500]*500, np.uint8)
cv2.imshow('average',average_color_img)
cv2.imwrite('avarage.jpg',average_color_img)
cv2.waitKey(0)

函数原型为：average(a, axis =None, weights=None) : 依给定轴axis计算数组a相关元素的加权平均值 

np.average() 对于3X3的矩阵是各个行列相应位置元素平均值计算；见下图

3、openCV 平均图像的颜色_python

截图一块小图片，其像素描述：

pixel= [
 [[ 6   15  29] [ 13  22  36] [104 114 131]]
 [[ 12  21  35] [ 42  51  65] [164 174 191]]
 [[  0   0  11] [ 14  23  37] [142 152 169]]
       ]

执行python 代码可知

average_img= [[   6.           12.           25.        ]
              [  23.           32.           46.        ]
              [ 136.66666667  146.66666667  163.66666667]]
average_img_weights= [[   6.           10.76470588   23.35294118]
                      [  27.11764706   36.11764706   50.11764706]
                      [ 150.11764706  160.11764706  177.11764706]]
average_color= [55 63 78]
计算过程可见 pixel ==>>average_img  未加权值参数weights

  6=(6+12+0)/3
  23=(13+42+14)/3
   ........
计算过程可见 pixel ==>>average_img  加权值参数weights
暂未看懂。。。。。 看懂小伙伴给我留言

3、openCV 平均图像的颜色_数组_02

关于axis描述：

3、openCV 平均图像的颜色_数组_03