OpenCV not working properly with python on Linux with anaconda. Getting error that cv2.imshow() is not implemented

I followed this tutorial (OpenCV GTK+2.x error) and did the following. It worked for me :

1. install the packages : libgtk2.0-dev and pkg-config
2. cd to your opencv directory
3. mkdir Release
4. cd Release
5. Run the command : cmake -D CMAKE_BUILD_TYPE=RELEASE -D CMAKE_INSTALL_PREFIX=/usr/local -D WITH_TBB=ON -D BUILD_NEW_PYTHON_SUPPORT=ON -D WITH_V4L=ON -D INSTALL_C_EXAMPLES=ON -D INSTALL_PYTHON_EXAMPLES=ON -D BUILD_EXAMPLES=ON -D WITH_QT=ON -D WITH_GTK=ON -D WITH_OPENGL=ON ..
6. make
7. sudo make install

If you installed OpenCV using the opencv-python pip package at any point in time, be aware of the following note, taken from https://pypi.python.org/pypi/opencv-python

IMPORTANT NOTE
MacOS and Linux wheels have currently some limitations:

• video related functionality is not supported (not compiled with FFmpeg)
• for example cv2.imshow() will not work (not compiled with GTK+ 2.x or Carbon support)

Also note that to install from another source, first you must remove the opencv-python package

Notice that it is complaining for libgtk2.0-dev and pkg-config. Here is the solution. Uninstall your existing openCV installation.

conda remove opencv3

Install these packages before installing opencv-
conda install gtk2 pkg-config

Now install opencv from menpo
conda install -c https://conda.anaconda.org/menpo opencv3

For me (Arch Linux, Anaconda with Python 3.6), installing from the suggested channels menpo or loopbio did not change anything. My solution (see related question) was to

1. install pkg-config (sudo pacman -Syu pkg-config),
2. remove opencv from the environment (conda remove opencv) and
3. re-install opencv from the conda-forge channel (conda install -c conda-forge opencv)

conda list now returns opencv 3.3.0 py36_blas_openblas_203 [blas_openblas] conda-forgeand all windows launched using cv2 are working fine.

I used pip to install opencv-python. (https://pypi.org/project/opencv-python/)

1) Remove the opencv package from conda:

>> conda remove opencv

2) To your env.yml file add this:

...
dependencies:
  - numpy
  - pytest
  ...
  - pip:
    - opencv-python

Remove opencv from anaconda=

conda remove opencv

Then, reinstall opencv using pip:

pip install opencv

This is working for me.

I have had to deal with this issue a couple of times, this is what has worked consistently thus far:

conda remove opencv
conda install -c menpo opencv
pip install --upgrade pip
pip install opencv-contrib-python

My Envirment is Win10, and I added the anaconda path to the environment variables’s PATH’,the cv2.imshow worked

C:UsersuserAnaconda3
C:UsersuserAnaconda3Scripts

Then restart the windows

Working method ( ‍ tested on April 19, 2019)

• These error happen because of conda.
• Open Anaconda Prompt and remove conda opencv if installed
• ‍ conda remove opencv

If you have conda env, firstly activate it conda activate <your_env_name>

• ⏬ After install opencv via pip (click here to offical info)
• ‍ pip install opencv-contrib-python

if pip haven’t installed, use conda install pip command.

Although this is already answered, for me conda-forge solution worked with a hack.
My workstation is a centos 6 machine, and I use conda virtual environment (anaconda 2). Create an environment

conda create --name test python=2.7

and then activate it

conda activate test

Now install opencv from conda-forge

conda install -c conda-forge opencv

Now install matplotlib in this environment (and this is hack 1)

conda install matplotlib

Let’s check now imshow works or not. In a terminal, activate test environment and start python. In the interpreter, do

import cv2
import matplotlib.pyplot as plt # hack 2
img = cv2.imread('your_image_file',0)
cv2.imshow('image',img)

This should pop up a window showing image. I did not further research how this solved the case.

Note 1: You may see some error related to xkb, then in your .bashrc file add

export QT_XKB_CONFIG_ROOT=/usr/share/X11/xkb

Note 2: You may see some error related to XDG_RUNTIME_DIR, then in your .bashrc file also add

export XDG_RUNTIME_DIR=.tmp/myruntime
and define myruntime by mkdir -p .tmp/myruntime

If you are running inside docker then you may get this error.Solution uninstall current and install the headless one

pip install opencv-python==3.4.5.20

pip install opencv-contrib-python==3.4.5.20

If you are writing to the image and displaying it, you may need the following

apt-get update && apt-get install -y libglib2.0-0 libsm6 libxext6 libxrender1

And if you are wondering how to get the display from Docker, it is possible via X11 in your host

For my system (Ubuntu 18.04) the following was working.
First:

sudo apt-get update -y

sudo apt-get install -y libgtk2.0-dev

conda create -n py35 python=3.5

conda activate py35

Then configure the environment

pip install Cython

pip install scikit-build

conda install -c anaconda cmake

pip install dlib

pip install face_recognition

pip install imutils

And finally:

pip install opencv-contrib-python

Easy with Ubuntu 18.04. It works for me:

Remove opencv-python:

pip3 uninstall opencv-python

And then re-install opencv-python:

pip3 install opencv-python

Issue was resolved.

My ubuntu 18.04 machine is running at AWS.
What helped me was (link):

pip uninstall opencv-python
pip install opencv-python==4.1.2.30

Afterwards I got the error: " : cannot connect to X server "

Finally, I managed to make it work by installing MobaXTerm (reference here).

FYI:

1. I connect to AWS with WinSCP. If you connect to AWS via something like WinSCP, the MobaXTerm interface lets you connect to the "WinSCP temporary session" if you click at "Sessions", which is very convenient. The session screen basically replaces the console but allows to display the image via a pop-up window.
2. In case you also experience the error ASSERT: “false” in file qasciikey.cpp, line 501 once cv.imshow() or similar is executed, go to the MobaXTerm interface, click Settings -> Configuration -> X11, uncheck "Unix-compatible keyboard" (reference here).

I was able to fix it by installing a previous version of opencv-contrib-python.

I’m using Ubuntu 18