如何使用 OpenCV 读取给定 link 的图像，然后使用 plt.imshow() 绘制它？

Question

我试过了

from PIL import Image
import requests

im = Image.open(requests.get('http://images.cocodataset.org/train2017/000000000086.jpg', stream=True).raw)
img = cv.imread('im.jpg')
print(img)

This works but print(img) prints "None". Also, shouldn't it be cv.imread(im)(doing that gives an error).

当我做的时候

plt.imshow(img)

报错

Image data of dtype object cannot be converted to float

Answer 1

我想你在阅读之前忘记将下载的图像图像文件保存到磁盘。

from PIL import Image
import requests
import cv2 as cv

im = Image.open(requests.get('http://images.cocodataset.org/train2017/000000000086.jpg', stream=True).raw)

im.save('im.jpg') # write image file to disk

img = cv.imread('im.jpg') # read image file from disk
print(img)

如果你想直接显示图片，不保存到磁盘，使用this approach from another answer:

import numpy as np

im = Image.open(...)
img = np.array(im) 
img = cv2.cvtColor(img, cv2.COLOR_BGR2RGB) # Convert RGB to BGR 
plt.imshow(img)
plt.show()

Answer 2

不确定我会引入 PIL 作为附加依赖项以及 OpenCV，也不会将图像写入磁盘。

我觉得这样更直接：

import cv2
import requests
import numpy as np

# Fetch JPEG data
d = requests.get('http://images.cocodataset.org/train2017/000000000086.jpg')

# Decode in-memory, compressed JPEG into Numpy array
im = cv2.imdecode(np.frombuffer(d.content,np.uint8), cv2.IMREAD_COLOR)

如何使用 OpenCV 读取给定 link 的图像，然后使用 plt.imshow() 绘制它？

How do I read an image given its link using OpenCV and then plot it using plt.imshow()?

opencv

python-imaging-library

opencv-python