import cv2 as cv

 import numpy as np

 # 图片缩放

 img = cv.imread('../images/moon.jpg', flags=1)  # flags=1读取为彩色，flags=0读取为灰度

 cv.imshow('i', img)

 h, w, channel = img.shape  # 以行列形式存储, 第几行到第几行为图像高度

 dst_h = int(h*0.5)

 dst_w = int(w*0.5)

 # 最近邻域差值 双线性插值 像素关系重采样 立方差值

 dst = cv.resize(img, (dst_w, dst_h))  # 默认双线性差值

 cv.imshow('img', dst)

 cv.waitKey(0)

 import cv2 as cv

 import numpy as np

 # 图片缩放

 img = cv.imread('../images/moon.jpg', flags=1)  # flags=1读取为彩色，flags=0读取为灰度

 h, w = img.shape[:2]

 mat_shift = np.float32([[0.5, 0, 0], [0, 0.5, 0]])  # 缩放矩阵

 dst = cv.warpAffine(img, mat_shift, (int(w/2), int(h/2)))

 cv.imshow('img1', img)

 cv.imshow('img2', dst)

 cv.waitKey(0)