记opencv-python-tutroals中关于Pyramids中Blending的错误

在官方文档的第84页中，对apple和orange图片的合成中，实例代码有几个地方需要注意，首先是pyrUp和pyrDown对图像先放大后缩小或者是先缩小后放大后，可能rows和cols和原图像不同，需要resize才能恢复，其次有个小错，就是np.hstack中对cols的参数写错了。贴上正确的代码。

(其实和文档里面的示例图片还是不同，有待进一步学习)

import cv2
import numpy as np
from matplotlib import pyplot as plt

A = cv2.imread('/Users/apple/Desktop/apple.jpg')
B = cv2.imread('/Users/apple/Desktop/orange.jpg')
rows, cols = A.shape[ : 2]
B = cv2.resize(B, (rows, cols))
G = A.copy()
gaA = [G]
for i in xrange(6):
G = cv2.pyrDown(G)
gaA.append(G)

G = B.copy()
gaB = [G]
for i in range(6):
G = cv2.pyrDown(G)
gaB.append(G)

lpA = [gaA[5]]
for i in xrange(5, 0, -1):
GE = cv2.pyrUp(gaA[i])
rows, cols = gaA[i - 1].shape[ : 2]
GE = cv2.resize(GE, (rows, cols))
L = cv2.subtract(gaA[i - 1],GE)
lpA.append(L)

lpB = [gaB[5]]
for i in xrange(5, 0, -1):
GE = cv2.pyrUp(gaB[i])
rows, cols = gaB[i - 1].shape[ : 2]
GE = cv2.resize(GE, (rows, cols))
L = cv2.subtract(gaB[i - 1], GE)
lpB.append(L)

LS = []

for la, lb in zip(lpA, lpB):
rows, cols, dpt = la.shape
ls = np.hstack((la[ :, 0 : cols / 2], lb[ :, cols / 2 : ]))
LS.append(ls)

ls_ = LS[0]
for x in xrange(1, 6):
ls_ = cv2.pyrUp(ls_)
rows, cols = ls_.shape[ : 2]
LS[i] = cv2.resize(LS[i], (rows, cols))
ls_ = cv2.add(ls_, LS[i])

real = np.hstack((A[ :, 0 : cols / 2], B[ :, cols / 2: ]))

cv2.imwrite('/Users/apple/Desktop/Pyramids_Blending.jpg', ls_)
cv2.imwrite('/Users/apple/Desktop/Direct_Blending.jpg', real)