opencv notes-image pyramid

Image Pyramid
Image pyramid is used for machine vision and image compression. The pyramid of an image is a series of pyramids arranged in a gradually decreasing resolution and is derived from the same collection of original images. It is obtained by cascading down sampling until it reaches Only a certain termination condition stops sampling.

The bottom of the image pyramid is the high-resolution representation to be processed, and the top is the approximation of the low-resolution. The higher the level, the smaller the image and the lower the resolution.

sampling:

up_img = cv.pyrUp(img)      # 上采样
down_img = cv.pyrDown(img)  # 下采样

Implementation code:

import numpy as np
import cv2 as cv
import matplotlib.pyplot as plt

# 图片加载
img = cv.imread('img/img2.jpeg')

# 采样
up_img = cv.pyrUp(img)      # 上采样
down_img = cv.pyrDown(img)  # 下采样
print(up_img.shape)         # (2160, 3840, 3)
print(down_img.shape)       # (540, 960, 3)
print(img.shape)            # (1080, 1920, 3)

# 图像显示
cv.imshow('enlarge',up_img)
cv.imshow('shrink',down_img)
cv.imshow('original',img)
cv.waitKey(0)

cv Xiaobai, hope the boss will give pointers