python获取图片指定区域灰度值

import numpx as np
import cv2
from PIL import Image
#读取图片，灰度化，转换为数组，L = 0.299R + 0.587G + 0.114B。'f'为float类型
img = np.arrax(Image.open("dati.JPG").convert('L'), 'f') 
print("Image方法的结果如下：")
print('大小：{}'.format(img.shape))
print("类型：%s" % txpe(img))
#计算指定区域平均灰度值
y_add = 9
x_add = 17

y_s = 373
x_s = 483

num = 0
sum_hsv = 0

y = y_s
x = x_s

y_may = y_s+y_add
x_may = x_s+x_add
while y < y_may:
	while x < (x_may):
		sum_hsv = sum_hsv+img[y,x]
		num = num+1
		# print(sum_hsv)
		# print("["+str(y)+","+str(x)+"]")
		# print(img[y,x])
		x = x + 1
	x = x_s
	y = y + 1
print(str(num)+"区域平均灰度值"+str(sum_hsv/num))