blocks|key|4943|text|Cv2.twareKey()的API文档注意到以下几点：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|4944|此函数是HighGUI中唯一能够获取和处理事件的方法，因此需要定期调用它来进行正常的事件处理，除非在负责事件处理的环境中使用HighGUI。|blockquote|4945|那么，也许在一个无穷无尽的循环中调用函数会使窗口响应吗？我还没有对此进行测试，但也许您想尝试以下几种方法：|4946|import+cv2

cvim2disp+=+cv2.imread('data/home.jpg')
cv2.imshow('img',+cvim2disp)
while(True):
++++k+=+cv2.waitKey(33)
++++if+k+==+-1:++#+if+no+key+was+pressed,+-1+is+returned
++++++++continue
++++else:
++++++++break
cv2.destroyWindow('img')|code-block|syntax|javascript|4947|entityMap|0|LINK|mutability|MUTABLE|url|https://docs.opencv.org/3.1.0/d7/dfc/group__highgui.html#ga5628525ad33f52eab17feebcfba38bd7^0|0|K|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|V|8|@]|9|@$A|W|B|X|1|Y]]|C|$]]|$1|D|3|E|5|F|7|Z|8|@]|9|@]|C|$]]|$1|G|3|H|5|6|7|10|8|@]|9|@]|C|$]]|$1|I|3|J|5|K|7|11|8|@]|9|@]|C|$L|M]]|$1|N|3|-4|5|6|7|12|8|@]|9|@]|C|$]]]|O|$P|$5|Q|R|S|C|$T|U]]]]

The <a href="https://docs.opencv.org/3.1.0/d7/dfc/group__highgui.html#ga5628525ad33f52eab17feebcfba38bd7" rel="noreferrer">API documentation for cv2.waitKey()</a> notes the following:

<blockquote>
 This function is the only method in HighGUI that can fetch and handle events, so it needs to be called periodically for normal event processing unless HighGUI is used within an environment that takes care of event processing.
</blockquote>

So perhaps calling the function in an endless loop would make the window responsive? I haven't tested this, but maybe you would like to try the following:

<pre><code>import cv2

cvim2disp = cv2.imread('data/home.jpg')
cv2.imshow('img', cvim2disp)
while(True):
 k = cv2.waitKey(33)
 if k == -1: # if no key was pressed, -1 is returned
 continue
 else:
 break
cv2.destroyWindow('img')
</code></pre>

blocks|key|4664|text|我不确定你能不能打开木星笔记本的窗户。cv2.imshow期望waitKey在木星中不起作用。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4665|下面是我所做的工作(使用OpenCV+3.3)：|4666|from+IPython.display+import+display,+HTML
import+cv2
import+base64

def+imshow(name,+imageArray):
+++++_,+png+=+cv2.imencode('.png',+imageArray)
+++++encoded+=+base64.b64encode(png)
+++++return+HTML(data='''<img+alt="{0}"+src="data:image/png;base64,+{1}"/>'''.format(name,+encoded.decode('ascii')))

img+=+cv2.imread('./media/baboon.jpg',cv2.IMREAD_COLOR)
imshow('baboon',+img)|code-block|syntax|javascript|4667|如果您不需要使用cv2，只需：|4668|from+IPython.display+import+Image
Image('./media/baboon.jpg')|4669|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|P|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|Q|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|R|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|S|8|@]|9|@]|A|$G|H]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

I am not sure if you can open a window from Jupyter Notebook. 
cv2.imshow expects a waitKey which doesn't work in Jupyter.

Here is what I have done (using OpenCV 3.3):

<pre><code>from IPython.display import display, HTML
import cv2
import base64

def imshow(name, imageArray):
 _, png = cv2.imencode('.png', imageArray)
 encoded = base64.b64encode(png)
 return HTML(data='''&lt;img alt="{0}" src="data:image/png;base64, {1}"/&gt;'''.format(name, encoded.decode('ascii')))

img = cv2.imread('./media/baboon.jpg',cv2.IMREAD_COLOR)
imshow('baboon', img)
</code></pre>

If you don't need to use cv2, just:

<pre><code>from IPython.display import Image
Image('./media/baboon.jpg')
</code></pre>

blocks|key|4968|text|我有一个类似的问题，并没有找到一个很好的解决方案与cv2.imshow()在木星笔记本。我遵循这个堆叠溢出的答案，只使用matplotlib来显示图像。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|4969|import+matplotlib.pyplot+as+plt
#+load+image+using+cv2....and+do+processing.
plt.imshow(cv2.cvtColor(image,+cv2.COLOR_BGR2RGB))
#+as+opencv+loads+in+BGR+format+by+default,+we+want+to+show+it+in+RGB.
plt.show()|code-block|syntax|javascript|4970|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/a/46460856/2928388^0|P|C|1B|9|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@$9|T|A|U|B|C]]|D|@$9|V|A|W|1|X]]|E|$]]|$1|F|3|G|5|H|7|Y|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Z|8|@]|D|@]|E|$]]]|L|$M|$5|N|O|P|E|$Q|R]]]]

I was having a similar problem, and could not come to a good solution with <code>cv2.imshow()</code> in the Jupyter Notebook. I followed <a href="https://stackoverflow.com/a/46460856/2928388">this stackoverflow answer</a>, just using matplotlib to display the image.

<pre><code>import matplotlib.pyplot as plt
# load image using cv2....and do processing.
plt.imshow(cv2.cvtColor(image, cv2.COLOR_BGR2RGB))
# as opencv loads in BGR format by default, we want to show it in RGB.
plt.show()
</code></pre>

blocks|key|1633492|text|这将帮助你理解正在发生的事情：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1633493|import+cv2
cvim2disp+=+cv2.imread('data/home.jpg')
cv2.imshow('HelloWorld',+cvim2disp)
cv2.waitKey(0)+
cv2.destroyWindow('HelloWorld')|code-block|syntax|javascript|1633494|waitKey(0)方法正在无限地等待输入。当您看到相应图像的帧时，不要尝试在右上角使用close关闭图像。|offset|length|style|CODE|1633495|而是按一些键。waitkey方法将把它作为输入，并返回一个值。此外，还可以检查按下哪个键来关闭框架。|1633496|另外，waitKey(33)将使帧保持活动时间为33+ms，然后自动关闭它。|1633497|如果存在，destroyWindow()将破坏当前帧。destroyAllWindows()将销毁当前存在的所有帧。|1633498|这会解决的。|1633499|entityMap^0|0|0|0|A|0|7|7|0|3|B|0|5|F|R|J|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|X|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Y|8|@$I|Z|J|10|K|L]]|9|@]|A|$]]|$1|M|3|N|5|6|7|11|8|@$I|12|J|13|K|L]]|9|@]|A|$]]|$1|O|3|P|5|6|7|14|8|@$I|15|J|16|K|L]]|9|@]|A|$]]|$1|Q|3|R|5|6|7|17|8|@$I|18|J|19|K|L]|$I|1A|J|1B|K|L]]|9|@]|A|$]]|$1|S|3|T|5|6|7|1C|8|@]|9|@]|A|$]]|$1|U|3|-4|5|6|7|1D|8|@]|9|@]|A|$]]]|V|$]]

This will help you understand what is happening:

<pre><code>import cv2
cvim2disp = cv2.imread('data/home.jpg')
cv2.imshow('HelloWorld', cvim2disp)
cv2.waitKey(0) 
cv2.destroyWindow('HelloWorld')
</code></pre>

<code>waitKey(0)</code> method is waiting for an input infinitely. When you see a frame of the corresponding image, do not try to close the image using close in top right corner. 

Instead press some key. <code>waitkey</code> method will take that as an input and it will return back a value. Further you can also check which key was pressed to close the frame.

Additionally <code>waitKey(33)</code> will keep the frame active for 33 ms and then close it automatically.

<code>destroyWindow()</code> will destroy the current frame if there.
<code>destroyAllWindows()</code> will destroy all the frames currently present.

This will solve.

blocks|key|4722|text|下面的代码在木星中很好地显示了一幅图像|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4723|%25matplotlib+inline
import+cv2
from+matplotlib+import+pyplot+as+plt
cap+=+cv2.VideoCapture(videoFName)
ret,+image+=+cap.read()
image=cv2.resize(image,None,fx=0.25,fy=0.25,interpolation=cv2.INTER_AREA)
plt.imshow(image)
plt.show()|code-block|syntax|javascript|4724|如果要在单独的窗口中显示视频而不是图像，请使用以下代码：|4725|import+cv2
cap+=+cv2.VideoCapture(videoFName)
while+cap.isOpened():
++++ret,+image+=+cap.read()
++++image=cv2.resize(image,None,fx=0.25,fy=0.25,interpolation=cv2.INTER_AREA)
++++cv2.imshow('image',image)

++++k+=+cv2.waitKey(30)+&+0xff+#+press+ESC+to+exit
++++if+k+==+27+or+cv2.getWindowProperty('image',+0)<0:
++++++++break
cv2.destroyAllWindows()
cap.release()|4726|确保窗口名称匹配，否则将无法工作。在本例中，我使用“image”作为窗口名称。|4727|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|S|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

The following code works fine in Jupyter to show one image

<pre><code>%matplotlib inline
import cv2
from matplotlib import pyplot as plt
cap = cv2.VideoCapture(videoFName)
ret, image = cap.read()
image=cv2.resize(image,None,fx=0.25,fy=0.25,interpolation=cv2.INTER_AREA)
plt.imshow(image)
plt.show()
</code></pre>

If you want to show the video instead of an image in a separate window, use the following code:

<pre><code>import cv2
cap = cv2.VideoCapture(videoFName)
while cap.isOpened():
 ret, image = cap.read()
 image=cv2.resize(image,None,fx=0.25,fy=0.25,interpolation=cv2.INTER_AREA)
 cv2.imshow('image',image)

 k = cv2.waitKey(30) &amp; 0xff # press ESC to exit
 if k == 27 or cv2.getWindowProperty('image', 0)&lt;0:
 break
cv2.destroyAllWindows()
cap.release()
</code></pre>

Make sure the window name match, otherwise it will not work. In this case I use 'image' as window name.

blocks|key|4738|text|从木星打开的新窗口使用与笔记本相同的内核。只需将以下内容添加到代码中，就可以正常工作。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4739|cv2.waitKey(0)
cv2.destroyAllWindows()|code-block|syntax|javascript|4740|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

The new window that opens up from Jupyter uses the same kernel as notebook. Just add this below to the code and it would work fine. 

<pre><code>cv2.waitKey(0)
cv2.destroyAllWindows()
</code></pre>

blocks|key|1633598|text|image+=+cv2.imread(file_path)
while+True:
++++#+Press+'q'+for+exit
++++exit_key+=+ord('q')
++++if+cv2.waitKey(exit_key)+&+255+==+exit_key:
++++++++cv2.destroyAllWindows()
++++++++break
++++cv2.imshow('Image_title',+image)|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1633599|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>image = cv2.imread(file_path)
while True:
 # Press 'q' for exit
 exit_key = ord('q')
 if cv2.waitKey(exit_key) &amp; 255 == exit_key:
 cv2.destroyAllWindows()
 break
 cv2.imshow('Image_title', image)
</code></pre>

blocks|key|4772|text|如果您在google+collab中遇到问题，可以使用此修补程序。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4773|from+google.colab.patches+import+cv2_imshow
cv2_imshow(img)|code-block|syntax|javascript|4774|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

if your facing problem in google collab ,you can use this patch
<pre><code>from google.colab.patches import cv2_imshow
cv2_imshow(img)
</code></pre>

blocks|key|4801|text|%25matplotlib+inline
from+matplotlib+import+pyplot+as+plt

img+=+cv2.imread(valid_img_paths[1])
plt.imshow(cv2.cvtColor(img,+cv2.COLOR_BGR2RGB))
plt.show()|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|4802|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>%matplotlib inline
from matplotlib import pyplot as plt

img = cv2.imread(valid_img_paths[1])
plt.imshow(cv2.cvtColor(img, cv2.COLOR_BGR2RGB))
plt.show()
</code></pre>

blocks|key|1633871|text|我刚刚开发了一个与cv2.imshow完全类似的库，它可以在Jupyter和colab中使用。它可以更新窗口。因此，你可以很容易地看到里面的视频。它使用HTML画布并对浏览器友好:)|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1633872|安装：|1633873|pip+install+opencv_jupyter_ui|1633874|用法：|1633875|这是cv2.imshow的替代木星。您只需将cv2.imshow替换为jcv2.imshow即可。它会在木星上工作。|1633876|第一：|1633877|请导入图书馆|1633878|import+opencv_jupyter_ui+as+jcv2|1633879|然后：|1633880|变更cv2.imshow+->jcv2.imshow|1633881|关于Github储存库还有更多的细节。粘结剂+演示gif|1633882|它还支持jcv2.waitKey(100)和jcv2.destroyAllWindows()。在没有木星的情况下，它会倒退到原来的cv2功能。为了更改默认键，可以使用jcv2.setKeys(['a','b','esc'])。请按文档查询更多信息|1633883|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/modaresimr/opencv_jupyter_ui|1|https://mybinder.org/v2/gh/modaresimr/opencv_jupyter_ui/HEAD?labpath=test.ipynb|2|https://raw.githubusercontent.com/modaresimr/opencv_jupyter_ui/main/test.gif|3^0|9|A|U|7|12|5|0|0|0|T|0|0|2|A|M|A|Z|B|0|0|0|0|W|0|0|2|A|F|B|0|2|9|0|J|3|1|N|5|2|0|4|H|M|O|2B|T|37|2|3|0^^$0|@$1|2|3|4|5|6|7|1E|8|@$9|1F|A|1G|B|C]|$9|1H|A|1I|B|C]|$9|1J|A|1K|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|1L|8|@]|D|@]|E|$]]|$1|H|3|I|5|6|7|1M|8|@$9|1N|A|1O|B|C]]|D|@]|E|$]]|$1|J|3|K|5|6|7|1P|8|@]|D|@]|E|$]]|$1|L|3|M|5|6|7|1Q|8|@$9|1R|A|1S|B|C]|$9|1T|A|1U|B|C]|$9|1V|A|1W|B|C]]|D|@]|E|$]]|$1|N|3|O|5|6|7|1X|8|@]|D|@]|E|$]]|$1|P|3|Q|5|6|7|1Y|8|@]|D|@]|E|$]]|$1|R|3|S|5|6|7|1Z|8|@$9|20|A|21|B|C]]|D|@]|E|$]]|$1|T|3|U|5|6|7|22|8|@]|D|@]|E|$]]|$1|V|3|W|5|6|7|23|8|@$9|24|A|25|B|C]|$9|26|A|27|B|C]]|D|@]|E|$]]|$1|X|3|Y|5|6|7|28|8|@]|D|@$9|29|A|2A|1|2B]|$9|2C|A|2D|1|2E]|$9|2F|A|2G|1|2H]]|E|$]]|$1|Z|3|10|5|6|7|2I|8|@$9|2J|A|2K|B|C]|$9|2L|A|2M|B|C]|$9|2N|A|2O|B|C]]|D|@$9|2P|A|2Q|1|2R]]|E|$]]|$1|11|3|-4|5|6|7|2S|8|@]|D|@]|E|$]]]|12|$13|$5|14|15|16|E|$17|18]]|19|$5|14|15|16|E|$17|1A]]|1B|$5|14|15|16|E|$17|1C]]|1D|$5|14|15|16|E|$17|18]]]]

I have just developed a library that is exactly similar to <code>cv2.imshow</code> and it can be used in both <code>Jupyter</code> and <code>colab</code>. It can update the window. Therefore you can easily see the video inside it. It uses HTML canvas and is browser friendly :)
<h1>Installation:</h1>
<code>pip install opencv_jupyter_ui</code>
<h1>Usage:</h1>
This is the replacement of <code>cv2.imshow</code> for Jupiter. you need only to replace <code>cv2.imshow</code> with <code>jcv2.imshow</code>. It will work in Jupiter.
<h2>First:</h2>
please import the library
<code>import opencv_jupyter_ui as jcv2</code>
<h2>Then:</h2>
change <code>cv2.imshow</code> -&gt;<code>jcv2.imshow</code>
More details exist on the <a href="https://github.com/modaresimr/opencv_jupyter_ui" rel="nofollow noreferrer">Github Repository</a>. <a href="https://mybinder.org/v2/gh/modaresimr/opencv_jupyter_ui/HEAD?labpath=test.ipynb" rel="nofollow noreferrer">Binder</a> <a href="https://raw.githubusercontent.com/modaresimr/opencv_jupyter_ui/main/test.gif" rel="nofollow noreferrer">Demo gif</a>
It also supports <code>jcv2.waitKey(100)</code> and <code>jcv2.destroyAllWindows()</code>. In case of the absence of Jupyter, it fallbacks to original cv2 functionality.
In order to change the default keys you can use <code>jcv2.setKeys(['a','b','esc'])</code>. Please follow the <a href="https://github.com/modaresimr/opencv_jupyter_ui" rel="nofollow noreferrer">document</a> for more information

I check other question on google or stackoverflow, they are talking about run cv2.imshow in script, but my code run in jupyter notebook.

Here is my configuration:

<ol>
<li>ubuntu 16.4x64</li>
<li>python 3.5</li>
<li>opencv 3.1.0</li>
</ol>

I start a jupyter notebook: here is the code I put it notebook:

<pre><code>%pylab notebook
import cv2

cvim2disp = cv2.imread('data/home.jpg')
cv2.imshow('HelloWorld', cvim2disp)
cv2.waitKey() #image will not show until this is called
cv2.destroyWindow('HelloWorld') #make sure window closes cleanly
</code></pre>

When I execute these code. image will show in a pop up window, but I can not close this window by clicking the x on the top right corner, and a moment later, system will prompt me that the window is not responding, it will give me 2 choices: "wait" , "fore quit". if I hit wait, then It will show the same prompt later, If I hit 'fore quit', then the jupyter notebook kernel die and I have to start over.

I google around, many solution suggest that I should add this code 

<pre><code>cv2.startWindowThread()
</code></pre>

before <code>imshow</code>, but situation get worse, the kernel hang forever!. 
anybody have some idea what's going on.

Here is the pic of my error:
<a href="https://i.stack.imgur.com/OzI8h.png" rel="noreferrer"><img src="https://i.stack.imgur.com/OzI8h.png" alt="enter image description here"></a>

opencv.imshow will cause jupyter notebook crash

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我检查了google或堆栈溢出的其他问题，他们说的是在脚本中运行cv2.imshow，但是我的代码运行在jupyter笔记本上。这是我的配置：ubuntu 16.4x64python 3.5opencv 3.1.0我启动了一个jupyter笔记本:下面是我把它放在笔记本上的代码：%pylab notebookimpor...

问opencv.imshow将导致jupyter笔记本崩溃
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问opencv.imshow将导致jupyter笔记本崩溃EN