Cannot find module cv2 when using OpenCV [duplicate]

First do run these commands inside Terminal/CMD:

conda update anaconda-navigator  
conda update navigator-updater  

Then the issue for the instruction below will be resolved

For windows if you have anaconda installed, you can simply do

pip install opencv-python

or

conda install -c https://conda.binstar.org/menpo opencv

if you are on linux you can do :

pip install opencv-python

or

conda install opencv 

Link1 Link2

For python3.5+ check these links : Link3 , Link4

Update:
if you use anaconda, you may simply use this as well (and hence don't need to add menpo channel):

conda install -c conda-forge opencv

This happens when python cannot refer to your default site-packages folder where you have kept the required python files or libraries

Add these lines in the code:

import sys

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

or before running the python command in bash move to /usr/local/lib/python2.7/site-packages directory. This is a work around if you don't want to add any thing to the code.

I solved my issue using the following command :

conda install opencv

Try to add the following line in ~/.bashrc

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

Python3.x User

sudo pip3 install opencv-python

For Windows 10 and Python 3.6, this worked for me

pip install opencv-contrib-python

pip install opencv-python

or

pip install opencv-python3 

will definitely work fine.

None of the above answers worked for me. I was going crazy until I found this solution below!

Simply run:

sudo apt install python-opencv

I solved my issue using the following command :

pip install opencv-python

I solve it by running:

pip3 install opencv-python

I solve this by run code pip install opencv_contrib_python

I have come accross same as this problem i installed cv2 by

pip install cv2

However when i import cv2 module it displayed no module named cv2 error.
Then i searched and find cv2.pyd files in my computer and i copy and paste to site-packages directory

C:\Python27\Lib\site-packages

then i closed and reopened existing application, it worked.

EDIT I will tell how to install cv2 correctly.

1. Firstly install numpy on your computer by

pip install numpy

2. Download opencv from internet (almost 266 mb).
I download opencv-2.4.12.exe for python 2.7. Then install this opencv-2.4.12.exe file.
I extracted to C:\Users\harun\Downloads to this folder.
After installation go look for cv2.py into the folders.
For me

C:\Users\harun\Downloads\opencv\build\python\2.7\x64

in this folder take thecv2.pyd and copy it in to the

C:\Python27\Lib\site-packages

now you can able to use cv2 in you python scripts.

Easy

python -m pip install --upgrade pip

Then

pip install opencv-python

For python3x users

$ sudo pip3 install opencv-python

For python2x users

$ sudo pip install opencv-python

IF YOU ARE BUILDING FROM SCRATCH, GO THROUGH THIS

You get No module named cv2.cv. Son, you did all step right, since your sudo make install gave no errors.

However look at this step

$ cd ~/.virtualenvs/cv/lib/python2.7/site-packages/
$ ln -s /usr/local/lib/python2.7/site-packages/cv2.so cv2.so

THE VERY IMPORTANT STEP OF ALL THESE IS TO LINK IT.

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

The moment you choose wise linking, or by brute force just find the cv2.so file if that exist or not

Here I am throwing my output.

    Successfully installed numpy-1.15.3
(cv) demonLover-desktop:~$ cd ~/.virtualenvs/cv/lib/python2.7/site-packages/
(cv) demonLover-desktop:~/.virtualenvs/cv/lib/python2.7/site-packages$ ln -s /usr/local/lib/python2.7/site-packages/cv2.so cv2.so
(cv) demonLover-desktop:~/.virtualenvs/cv/lib/python2.7/site-packages$ pip list
Package    Version
---------- -------
numpy      1.15.3 
pip        18.1   
setuptools 40.5.0 
wheel      0.32.2 
(cv) demonLover-desktop:~/.virtualenvs/cv/lib/python2.7/site-packages$ python
Python 2.7.12 (default, Dec  4 2017, 14:50:18) 
[GCC 5.4.0 20160609] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import cv2
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ImportError: No module named cv2
>>> 
[2]+  Stopped                 python
(cv) demonLover-desktop:~/.virtualenvs/cv/lib/python2.7/site-packages$ ls /usr/local/lib/python2.7/site-packages/c
ls: cannot access '/usr/local/lib/python2.7/site-packages/c': No such file or directory
(cv) demonLover-desktop:~/.virtualenvs/cv/lib/python2.7/site-packages$ ls /usr/local/lib/python2.7/site-packages/
(cv) demonLover-desktop:~/.virtualenvs/cv/lib/python2.7/site-packages$ deactivate 
demonLover-desktop:~/.virtualenvs/cv/lib/python2.7/site-packages$ ls /usr/local/lib/python2.7/site-packages/
demonLover-desktop:~/.virtualenvs/cv/lib/python2.7/site-packages$ ls
cv2.so  easy_install.py  easy_install.pyc  numpy  numpy-1.15.3.dist-info  pip  pip-18.1.dist-info  pkg_resources  setuptools  setuptools-40.5.0.dist-info  wheel  wheel-0.32.2.dist-info
demonLover-desktop:~/.virtualenvs/cv/lib/python2.7/site-packages$ ls /usr/local/lib/python2.7/site-packages/
demonLover-desktop:~/.virtualenvs/cv/lib/python2.7/site-packages$ ls -l  /usr/local/lib/python2.7/site-packages/
total 0
demonLover-desktop:~/.virtualenvs/cv/lib/python2.7/site-packages$ ls
cv2.so  easy_install.py  easy_install.pyc  numpy  numpy-1.15.3.dist-info  pip  pip-18.1.dist-info  pkg_resources  setuptools  setuptools-40.5.0.dist-info  wheel  wheel-0.32.2.dist-info
demonLover-desktop:~/.virtualenvs/cv/lib/python2.7/site-packages$ workon cv
(cv) demonLover-desktop:~/.virtualenvs/cv/lib/python2.7/site-packages$ python
Python 2.7.12 (default, Dec  4 2017, 14:50:18) 
[GCC 5.4.0 20160609] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import cv2
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ImportError: No module named cv2
>>> 
[3]+  Stopped                 python
(cv) demonLover-desktop:~/.virtualenvs/cv/lib/python2.7/site-packages$ find / -name "cv2.so"
find: ‘/lost+found’: Permission denied
find: ‘/run/udisks2’: Permission denied
find: ‘/run/docker’: Permission denied
find: ‘/run/exim4’: Permission denied
find: ‘/run/lightdm’: Permission denied
find: ‘/run/cups/certs’: Permission denied
find: ‘/run/sudo’: Permission denied
find: ‘/run/samba/ncalrpc/np’: Permission denied
find: ‘/run/postgresql/9.5-main.pg_stat_tmp’: Permission denied
find: ‘/run/postgresql/10-main.pg_stat_tmp’: Permission denied
find: ‘/run/lvm’: Permission denied
find: ‘/run/systemd/inaccessible’: Permission denied
find: ‘/run/lock/lvm’: Permission denied
find: ‘/root’: Permission denied
^C
(cv) demonLover-desktop:~/.virtualenvs/cv/lib/python2.7/site-packages$ sudofind / -name "cv2.so"
sudofind: command not found
(cv) demonLover-desktop:~/.virtualenvs/cv/lib/python2.7/site-packages$ ^C
(cv) demonLover-desktop:~/.virtualenvs/cv/lib/python2.7/site-packages$ sudo find / -name "cv2.so"
[sudo] password for app: 
find: ‘/run/user/1000/gvfs’: Permission denied
^C
(cv) demonLover-desktop:~/.virtualenvs/cv/lib/python2.7/site-packages$ sudo find /usr/ -name "cv2.so"
/usr/local/lib/python2.7/dist-packages/cv2.so
^C
(cv) demonLover-desktop:~/.virtualenvs/cv/lib/python2.7/site-packages$ ln -s /usr/local/lib/python2.7/dist-packages/ccv2.so cv2.so
click/                        clonevirtualenv.pyc           configparser-3.5.0.dist-info/ configparser.py               cv2.so                        cycler.py
clonevirtualenv.py            concurrent/                   configparser-3.5.0-nspkg.pth  configparser.pyc              cycler-0.10.0.dist-info/      cycler.pyc
(cv) demonLover-desktop:~/.virtualenvs/cv/lib/python2.7/site-packages$ ln -s /usr/local/lib/python2.7/dist-packages/cv2.so cv2.so
ln: failed to create symbolic link 'cv2.so': File exists
(cv) demonLover-desktop:~/.virtualenvs/cv/lib/python2.7/site-packages$ rm cv2.so 
(cv) demonLover-desktop:~/.virtualenvs/cv/lib/python2.7/site-packages$ ln -s /usr/local/lib/python2.7/dist-packages/cv2.so cv2.so
(cv) demonLover-desktop:~/.virtualenvs/cv/lib/python2.7/site-packages$ ls
cv2.so  easy_install.py  easy_install.pyc  numpy  numpy-1.15.3.dist-info  pip  pip-18.1.dist-info  pkg_resources  setuptools  setuptools-40.5.0.dist-info  wheel  wheel-0.32.2.dist-info
(cv) demonLover-desktop:~/.virtualenvs/cv/lib/python2.7/site-packages$ python
Python 2.7.12 (default, Dec  4 2017, 14:50:18) 
[GCC 5.4.0 20160609] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import cv2
>>> 

My step will only help, if your built is done right.

If want to install opencv in virtual environment. Run command in terminal for getting virtual environment list.

conda env list

or jupyter notebook command is

!conda env list

Then update your anaconda.

conda update anaconda-navigator
conda update navigator-updater

Install opencv in your selected environment path.

conda install -c ['environment path'] opencv

Juypter notebook

!conda install --yes --prefix ['environment path'] opencv

Create a virtual environment and then install open-cv there. It worked for me. And, it is best practice to create a virtual environment. Create a virtual environment:

python3 -m venv env

Activating virtual environment For Linux:

source env/bin/activate

Install OpenCV and other modules now.

pip3 install opencv-python

Above will work for linux. Similarly, you can create virtual environment for windows and then install opencv More on Virtual Environment:

• https://docs.python.org/3/library/venv.html
  
• https://www.geeksforgeeks.org/creating-python-virtual-environment-windows-linux/

I had opencv installed and I tried to upgrade pip and opencv both but i didnt work. this worked for me

pip install opencv-contrib-python<4.6.0

The best way for me to solve this problem was to install python3-venv and create a new environment, then install my packages, because any method presented here could not solve the problem and always resulted in the same error. Maybe my solution could be helpful to others:

1- install python3-venv
2- Create and activate new venv
3- pip3 install opencv-python

Try this out:

sudo ldconfig

sudo nano /etc/ld.so.conf.d/opencv.conf

and add this following line in the opencv.conf not in the command window

/usr/local/lib

Then:

sudo ldconfig

sudo nano /etc/bash.bashrc

and add this two lines in the bash.bashrc not in the command window

PKG_CONFIG_PATH=$PKG_CONFIG_PATH:/usr/local/lib/pkgconfig       
export PKG_CONFIG_PATH

at last reboot your Pi sudo reboot now

and try import cv2

Another way I got opencv to install and work was inside visual studio 2017 community. Visual studio has a nice python environment with debugging.
So from the vs python env window I searched and added opencv. Just thought I would share because I like to try things different ways and on different computers.

I had the same problem, just couldn't figure it out with opencv2 and opencv3 installed into /opt/opencv and opencv3 respectively. Turned out that bloody anaconda install of opencv in my home directory was first on path and mangled opencv. Removed it and started using /opt/opencv3/lib as defined in /etc/ld.so.conf.d/opencv.conf. Worked perfectly first go. Do you have anaconda installed? Could be the issue.

I know you had the issue with Occidentalis, but I had the issue on Windows too, and I didn't found anything helpful. So if you have windows, and you've installed opencv, but you still get an Import error, this method will maybe solve the issue.

I managed to solve the issue, by reactivating anaconda.

First I deleted your\path\to\anaconda3 and your\path\to\anaconda3\Scripts from PATH (you will need these later, so remember these paths)

Then if you run python from cmd it will say:

Warning:
This Python interpreter is in a conda environment, but the environment has
not been activated. Libraries may fail to load. To activate this environment
please see https://conda.io/activation.

Then in Anaconda prompt I ran these:

your\path\to\anconda3\Scripts\activate base 
conda activate --stack your\path\to\anaconda3

I'm not sure about is this the easiest way to reactivate anaconda, but this is what worked for me.

This is for those who are using ubuntu to run their script.py you have to copy cv2.so under your python pachkages dir and then resourcing your bachrc. here:

sudo cp -rfv /home/<user>/<your opencv file dir>/lib/cv2.so  /usr/local/lib/python2.7/site-packages/
export PYTHONPATH=/usr/local/lib/python2.7/site-packages:$PYTHONPATH

This Question Have easy Solutions

1. Install Anconda Navigator
2. Then Go to Environment And Search "Opencv"
3. Add the Tick Mark and Apply Install
4. Finally slove the Problem

I worked with the code below and it worked perfectly well;

pip install opencv-python==4.6.0.66