import cv2
img = cv2.imread('libarary.JPG', 1)dst = img[350:650,550:800]  #这里选取矩形区域X：550-800  Y：350-650#cv2.imshow('image',dst)
#cv2.waitKey(0)

以下会在jupyterLab控件中显示两种压缩后的图像对比显示

#bgr8转jpeg格式
import enum
import cv2def bgr8_to_jpeg(value, quality=75):return bytes(cv2.imencode('.jpg', value)[1])

import ipywidgets.widgets as widgetsimage_widget1 = widgets.Image(format='jpg', )
image_widget2 = widgets.Image(format='jpg', )# display the container in this cell's output
display(image_widget1)
display(image_widget2)img1 = cv2.imread('libarary.JPG',1)image_widget1.value = bgr8_to_jpeg(img1)  #原始图像
image_widget2.value = bgr8_to_jpeg(dst)   #剪切的图像