如何计算每个像素值的平均值

Question

我想计算每个像素值的平均值，以及如何分别显示它们。例如：平均值124.34(红色(、124.44(绿色(、124.67(蓝色(、123.56(灰色(我试着这样。。。

import numpy as np
import math 
img = Image.open('cameraman.jpg')
h,w=img.size 
#print(h,w)
arr = np.array(img)
total = 0 
for i in range(arr.shape[0]):
for j in range(arr.shape[1]):
total+=arr[(i,j)]
a=h*w
mean=(total)/a
print("Mean Value is: ",np.mean)

Answer 1

最短答案(阮B.(：

import cv2
import numpy
myimg = cv2.imread('image.jpg')
avg_color_per_row = numpy.average(myimg, axis=0)
avg_color = numpy.average(avg_color_per_row, axis=0)
print(avg_color)

结果：

Blue           Green          Red
[ 197.53434769  217.88439451  209.63799938]

更扩展，类似于您自己的方法：若使用opencv，访问像素将返回一个具有BGR颜色的数组。

import cv2
import numpy as np
img = cv2.imread('your_image.jpg')
totalBlue = 0
totalGreen = 0
totalRed = 0
totalPixels = 0
for line in img:
for px in line:
totalBlue += px[0]
totalGreen += px[1]
totalRed += px[2]
totalPixels += 1
meanBlue = totalBlue/totalPixels
meanGreen = totalGreen/totalPixels
meanRed = totalRed/totalPixels

要获得灰度平均值，您可以使用将图像加载为黑白图像

img = cv2.imread('your_image.jpg', 0)