Python various methods of reading images

1. Read the image

Use matplotlib. image

from matplotlib import image as mping
from matplotlib import  pyplot as plt
import numpy as np
img=mping.imread('美女.jpg')#image.read()
plt.imshow(img)#图片显示
plt.show()#画布显示
print(type(img))
print(img.shape)

Use opencv

import cv2
from matplotlib import  pyplot as plt
import numpy as np
img=cv2.imread('meinv (2).jpg')#
cv2.imshow('image',img)
cv2.waitKey(0)
cv2.destroyAllWindows()
print(type(img))
print(img.shape)

import cv2
from matplotlib import  pyplot as plt
import numpy as np
img=cv2.imread('meinv (2).jpg')#
plt.imshow(img)
plt.show()
print(type(img))
print(img.shape)

opencv saves BGR.matplotlib saves RGB

If you want to display as RGB normally, you need to add

img=cv2.cvtColor(img,cv2.COLOR_BGR2RGB)#BGR-RGB

Use PIL

from PIL import Image
from matplotlib import  pyplot as plt
import numpy as np
img=Image.open('meinv (2).jpg')#

plt.imshow(img)
plt.show()
print(type(img))
print(img.shape)

The picture read by PIL is not in numpy format

Need for manual conversion

from PIL import Image
from matplotlib import  pyplot as plt
import numpy as np
img=Image.open('meinv (2).jpg')#
img=np.array(img)
plt.imshow(img)
plt.show()
print(type(img))
print(img.shape)

2. Zoom image

PIL zoom

from PIL import Image,ImageOps
from matplotlib import  pyplot as plt
import numpy as np
img=Image.open('meinv (2).jpg')#
img=np.array(img)#保存为numpy

img1=Image.fromarray(img)#读取numpy格式
print(img1.size)#(670, 419)
#缩放
img2=img1.resize((200,200))
print(img2.size)#(200, 200)

fig=plt.figure(figsize=(12,12))
a=fig.add_subplot(2,1,1)
imgplot=plt.imshow(img1)
a.set_title('before')

a=fig.add_subplot(2,1,2)
imgplot=plt.imshow(img2)
a.set_title('after')
plt.show()

Method two use
numpy.resize() method three use cv2.resize()

The syntax format
cv2.resize() has many parameters, among which src and dsize must be
cv2.resize(src.dsize)
src original image path
dsize target image size (column, row)
cv2.resize(src.dsize, fx, fy)
fx, fy zoom size ratio, when dsize is not used.
b=cv2.resize(a,dszie=None,fx=0.5,fy=0.5)

import cv2
import numpy as np
a=cv2.imread("image\\lenacolor.png")
b=cv2.resize(a,None,fx=1.2,fy=0.5)
cv2.imshow("original",a)
cv2.imshow("resize",b)
cv2.waitKey()
cv2.destroyAllWindows()