在 Ubuntu 上安装 OpenCV for Python，得到 Import Error: No module name cv2.cv

我有一个 Ubuntu 14.04系统，我想在上面安装 OpenCV 并与 Python 2.x 一起使用它。

我使用这里的说明安装了 OpenCV: Https://help.ubuntu.com/community/opencv

安装似乎运行正常，没有错误，脚本以输出结束

OpenCV 2.4.9 ready to be used

当我尝试运行示例 Python 脚本时，我得到以下结果:

$ python opencv.py
Traceback (most recent call last):
File "opencv.py", line 1, in <module>
from cv2.cv import *
ImportError: No module named cv2.cv

我想我知道原因，只是不知道如何弥补。在我运行安装脚本的工作目录上安装了 OpenCV，它是我主文件夹的一个子目录。

其他在安装之后出现这个导入错误的用户似乎遇到了路径问题，并且很幸运地将这个错误添加到了他们的代码中:

import sys
sys.path.append('/usr/local/lib/python2.7/site-packages')

或者使用相同的目录更新它们的 PYTHONPATH。我试过加入那个代码，但没用。我没有看到任何文件在“网站包”目录。我应该在那个目录下安装吗？我想安装说明应该已经说明了这一点。我怀疑我的问题与 Python 没有找到 OpenCV 安装有关，但我不确定如何继续下去。

请帮助我尽可能简单地安装 OpenCV。

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Use pip:

https://pypi.python.org/pypi/pip

$ pip install SomePackage
[...]
Successfully installed SomePackage

And when you add a path to PYTHONPATH with sys, PYTHONPATH it's always restarted to default values when you close your Python shell. Check this thread:

Permanently add a directory to PYTHONPATH

First add openCV to your path (Quick guide):

https://help.ubuntu.com/community/OpenCV

after that, install the non-python packages pyopencv depends on:

sudo apt-get build-dep python-opencv

finally, use pip:

pip install pyopencv

Also, you can check this tutorial to install openCV in ubuntu 14.04 LTS

http://www.samontab.com/web/2014/06/installing-opencv-2-4-9-in-ubuntu-14-04-lts/

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I found a solution in the guide here:

http://www.samontab.com/web/2014/06/installing-opencv-2-4-9-in-ubuntu-14-04-lts/

I resorted to compiling and installing from source. The process was very smooth, had I known, I would have started with that instead of trying to find a more simple way to install. Hopefully this information is helpful to someone.

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If you want as simple as possible, install from the repository:

sudo apt-get install python-opencv libopencv-dev python-numpy python-dev
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I think you don't have the python-opencv package.

I had the exact same problem and 

sudo apt-get install python-opencv

solved the issue for me.

you can install opencv from the following link https://www.learnopencv.com/install-opencv3-on-ubuntu/ It works for me . apt-get install doesnt contain many packages of opencv

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Verify if cv2.so did compile, should be placed in: /usr/local/lib/python2.7/site-packages Then export that path like this

export PYTHONPATH=/usr/local/lib/python2.7/site-packages:$PYTHONPATH

Same as in the answer here

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My environment:

  • Ubuntu 15.10
  • Python 3.5

Since none of the previous answers worked for me, I downloaded OpenCV 3.0 from http://opencv.org/downloads.html and followed the installation manual. I used the following cmake command:

$ ~/Programs/opencv-3.0.0$ cmake -D CMAKE_BUILD_TYPE=Release -D CMAKE_INSTALL_PREFIX=/usr/local -D PYTHON3_EXECUTABLE=/usr/bin/python3.5 -D PYTHON_INCLUDE_DIR=/usr/include/python3.5 -D PYTHON_INCLUDE_DIR2=/usr/include/x86_64-linux-gnu/python3.5m -D PYTHON_LIBRARY=/usr/lib/x86_64-linux-gnu/libpython3.5m.so -D PYTHON3_NUMPY_INCLUDE_DIRS=/usr/lib/python3/dist-packages/numpy/core/include/ -D PYTHON3_PACKAGES_PATH=/usr/lib/python3/dist-packages ..

Each step of the tutorial is important. Particularly, don't forget to call sudo make install.

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I also had this issue. Tried different things. But finally

conda install opencv

worked for me.

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Find where the cv2.so is, for example /usr/local/lib/python2.7/dist-packages, then add this into your ~/.bashrc by doing:

sudo gedit ~/.bashrc

and add 

export PYTHONPATH=/usr/local/lib/python2.7/dist-packages:$PYTHONPATH

In the last line

And then remember to open another terminal, this can be work, and I have solve my problem. Hope it can help you.

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Create a symbolic link to OpenCV. Eg:

cd ~/.virtualenvs/cv/lib/python2.7/site-packages/
ln -s /usr/local/lib/python2.7/dist-packages/cv2.so cv2.so
ln -s /usr/local/lib/python2.7/dist-packages/cv.py cv.py
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If you really sure that you installed cv2 but it gives no module error. There is a solution for this. Probably you have cv2.so file in your directory

/usr/local/lib/python2.7/site-packages/cv2.so

move this cv2.so file to

/usr/lib/python2.7/site-packages

copy the file into site-packages directory

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Try conda install -c conda-forge opencv if you are using anaconda, it works!

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For those who are trying to use 3.1.0 but after installing python says "cv2 module not found".

You likely have python but not python-dev.

sudo apt-get install python-dev

then reinstall 3.1.0 and it'll work.

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This seemed to work for me on Max OSX: https://anaconda.org/menpo/opencv3

conda install -c menpo opencv3=3.1.0

I confirmed that you can import cv2 in python using python2.7 and python3

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if you are using pycharm platform it's very simple go into view=>tool windows==>python console after that you will see in the bottom the console with [1] : type this !pip install opencv-python

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For me, this problem was due to the fact that I had not appropriately sym-linked the cv2.so file in the~/.virtualenvs/cv/lib/python3.5/site-packages folder (the name of your virualenv may not be "cv", your version of python may not be 3.5--adjust accordingly).

If you go to the ~/.virtualenvs/cv/lib/python3.5/site-packages folder and ls, the cv2.so file should appear in light blue (Ubuntu 16.04) showing that it is linked. You can check the link location by typing: readlink cv2.so

If cv2.so appears in red (as mine did), rm the file and type: (for my install of python 3.5)

ln -s /usr/local/lib/python3.5/dist-packages/cv2.cpython-35m-x86_64-linux-gnu.so cv2.so

OR (if you have python 3.6)

ln -s /usr/local/lib/python3.6/dist-packages/cv2.cpython-36m-x86_64-linux-gnu.so cv2.so

If you are working in python 2.6 or python 2.7, you instead type:

ln -s /usr/local/lib/python2.7/dist-packages/cv2.so cv2.so

If the cv2.so or cv2.cpython-36m-x86_64-linux-gnu.so files do not exist in your /usr/local/lib/python***/dist-packages location, check to see if they're in a /usr/local/lib/python***/sites-packages folder. If so, adjust the path accordingly. If not, something has gone wrong with your opencv installation.

This answer was inspired by information here: https://www.pyimagesearch.com/2016/10/24/ubuntu-16-04-how-to-install-opencv/

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Try using: from cv2 import cv

It works for me.

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Its complete installation nightmare, but I'll give one more hope you can avoid building opencv from source:

pip install opencv-contrib-python

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I tried all the other options here, but I could not get import cv2 working with Anaconda on Ubuntu. This is the only thing that helped:

pip install opencv-python

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You can build for source following the official OpenCV tutorial. The crucial part is to set the PYTHON3_EXECUTABLE, PYTHON_LIBRARY, PYTHON3_PACKAGES_PATH and PYTHON3_NUMPY_INCLUDE_DIRS parameters for python3.6. Here are all the steps:

  1. Clone the repo

    git clone https://github.com/opencv/opencv.git

  2. Create build directory

    cd ~/opencv
mkdir build
cd build

  3. Configure

    cmake -D CMAKE_BUILD_TYPE=RELEASE \
-D CMAKE_INSTALL_PREFIX=/usr/local .. \
-D PYTHON_INCLUDE_DIR=/usr/include/python3.6 \
-D PYTHON_INCLUDE_DIR2=/usr/include/x86_64-linux-gnu/python3.6m \
-D BUILD_NEW_PYTHON_SUPPORT=ON \
-D BUILD_opencv_python3=ON \
-D HAVE_opencv_python3=ON \
-D INSTALL_PYTHON_EXAMPLES=ON \
-D PYTHON3_EXECUTABLE=/usr/bin/python3.6 \
-D PYTHON_DEFAULT_EXECUTABLE=/usr/bin/python3.6 \
-D PYTHON_LIBRARY=/usr/lib/x86_64-linux-gnu/libpython3.6m.so \
-D PYTHON3_PACKAGES_PATH=/usr/lib/python3/dist-packages .. \
-D PYTHON3_NUMPY_INCLUDE_DIRS=/home/user/.local/lib/python3.6/site-packages/numpy/core/include/

  4. Build

    make -j8

  5. Install libraries

    sudo make install

  6. Test

    python3
import cv2

If you don't get the error "No module named cv2", then the installation was successful.

Note: If you don't know the path to numpy for the PYTHON3_NUMPY_INCLUDE_DIRS parameter, you can find it by executing import numpy and then numpy.__file__ in a python3 shell.

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try using sudo apt install python3-opencv

it will install the latest package of open cv.

Or you could try reinstalling the opencv package. It might have got corrupted during installation.

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Uninstall pandas, then install it again:

pip uninstall pandas
pip install pandas
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This solved my problem:

sudo apt-get install python3

then

pip3 install opencv-python
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The error kept appearing to me after downloading openCV 5 times in a different ways, until i fond that all of them has downloaded in a random version of Python, all of them in ~/usr/local/lib/python3.10 and the latest version is 3.11 (which i expected that the terminal should be using it when i write 'python3').

that was the problem in my case, i just changed python version in vscode.


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