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macOS: Install OpenCV 3 and Python 3.5

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Last week I covered how to install OpenCV 3 with Python 2.7 bindings on macOS Sierra and above.

In today’s tutorial we’ll learn how to install OpenCV 3 with Python 3.5 bindings on macOS.

I decided to break these install tutorials into two separate guides to keep them well organized and easy to follow.

To learn how to install OpenCV 3 with Python 3.5 bindings on your macOS system, just keep reading.

macOS: Install OpenCV 3 and Python 3.5

As I mentioned in the introduction to this post, I spent last week covering how to install OpenCV 3 with Python 2.7 bindings on macOS.

Many of the steps in last week’s tutorial and today’s tutorial are very similar (and in some cases identical) so I’ve tried to trim down some of the explanations for each step to reduce redundancy. If you find any step confusing or troublesome I would suggest referring to the OpenCV 3 + Python 2.7 tutorial where I have provided more insight.

The exception to this is “Step #7: Configure OpenCV 3 and Python 3.5 via CMake on macOS” where I provide an extremely thorough walkthrough on how to configure your OpenCV build. You should pay extra special attention to this step to ensure your OpenCV build has been configured correctly.

With all that said, let’s go ahead and install OpenCV 3 with Python 3.5 bindings on macOS.

Step #1: Install Xcode

Before we can compile OpenCV on our system, we first need to install Xcode, Apple’s set of software development tools for the Mac Operating System.

The easiest method to download Xcode is to open up the App Store application on your desktop, search for “Xcode” in the search bar, and then click the “Get” button:

Figure 1: Downloading and installing Xcode on macOS.
Figure 1: Downloading and installing Xcode on macOS.

After installing Xcode you’ll want to open up a terminal and ensure you have accepted the developer license:

$ sudo xcodebuild -license

We also need to install the Apple Command Line Tools. These tools include programs and libraries such as GCC, make, clang, etc. You can use the following command to install the Apple Command Line Tools:

$ sudo xcode-select --install

When executing the above command a confirmation window will pop up asking for you to confirm the install:

Figure 2: Installing the Apple Command Line Tools on macOS.
Figure 2: Installing the Apple Command Line Tools on macOS.

Click the “Install” button to continue. The actual installation process should take less than 5 minutes to complete.

Step #2: Install Homebrew

The next step is to install Homebrew, a package manager for macOS. You can think of Homebrew as the macOS equivalent of Ubuntu/Debian-based apt-get.

Installing Homebrew itself is super easy, just copy and paste the entire command below:

$ /usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

Once Homebrew is installed you should make sure the package definitions are up to date by running:

$ brew update

We now need to update our ~/.bash_profile file (or create it if it doesn’t exist already). Open up the file using your favorite text editor (I’m using nano in this case):

$ nano ~/.bash_profile

And then add the following lines to the file:

# Homebrew
export PATH=/usr/local/bin:$PATH

This export command simply updates the PATH variable to look for binaries/libraries along the Homebrew path before the system path is consulted.

I have included a screenshot of what my ~/.bash_profile looks like as reference below:

Figure 3: Updating my .bash_profile file to include Homebrew.
Figure 3: Updating my .bash_profile file to include Homebrew.

After updating your .bash_profile file, save and exitor the editor followed by using source to ensure the changes to the .bash_profile are manually reloaded:

$ source ~/.bash_profile

This command only needs to be executed once. Anytime you open up a new terminal your .bash_profile will automatically be source ‘d for you.

Step #3: Setup Homebrew for Python 3.5 and macOS

It is considered bad form to develop against the system Python as your main interpreter. The system version of Python should serve only one purpose — support system routines and operations. There is also the fact that macOS does not ship with Python 3 out of the box.

Instead, you should install your own version of Python that is independent from the system install. Using Homebrew, we can install Python 3 using the following command:

$ brew install python3

Note: Make sure you don’t forget the “3” in “python3”. The above command will install Python 3.5 on your system. However, if you leave off the “3” you’ll end up installing Python 2.7.

As a sanity check, it’s important to confirm that you are using the Homebrew version of Python 3 rather than the system version of Python 3. To accomplish this, simply use the which command:

$ which python3
/usr/local/bin/python3

Important: Inspect this output closely. If you see /usr/local/bin/python3 then you are correctly using the Homebrew version of Python. However, if the output is /usr/bin/python3 then you are incorrectly using the system version of Python.

If you find yourself using the system version of Python instead of the Homebrew version you should:

  1. Ensure Homebrew installed without error.
  2. Check that brew install python3 finished successfully.
  3. You have properly updated your ~/.bash_profile and reloaded the changes using source . This basically boils down to making sure your ~/.bash_profile looks like mine above in Figure 3.

Step #4: Install Python virtual environments and NumPy

We’ve made good progress so far. We’ve installed a non-system version of Python 3 via Homebrew. However, let’s not stop there. Let’s install both virtualenv and virtualenvwrapper so we can create separate, independent Python environments for each project we are working on — this is considered a best practice when developing software in the Python programming language.

I’ve already discussed Python virtual environments ad nauseam in previous blog posts, so if you’re curious about how they work and why we use them, please refer to the first half of this blog post. I also highly recommend reading through this excellent tutorial on the RealPython.com blog that takes a deeper dive into Python virtual environments.

Install virtualenv and virtualenvwrapper

Installing both virtualenv and virtualenvwrapper is a snap using pip :

$ pip install virtualenv virtualenvwrapper

After these packages have been installed we need to update our ~/.bash_profile again:

$ nano ~/.bash_profile

Once opened, append the following lines to the file:

# Virtualenv/VirtualenvWrapper
source /usr/local/bin/virtualenvwrapper.sh

After updating, your ~/.bash_profile should look similar to mine:

Figure 4: Updating your .bash_profile file to include virtualenv/virtualenvwrapper.
Figure 4: Updating your .bash_profile file to include virtualenv/virtualenvwrapper.

After updating your .bash_profile , save it, exit, and then once again source it:

$ source ~/.bash_profile

I’ll reiterate that this command only needs to be executed once. Each time you open up a new terminal window this file will automatically be source ‘d for you.

Create your Python 3 virtual environment

We can now use the mkvirtualenv command to create a Python 3 virtual environment named cv :

$ mkvirtualenv cv -p python3

The -p python3 switch ensures that a Python 3 virtual environment is created instead of a Python 2.7 one.

Again, the above command will create a Python environment named cv that is independent from all other Python environments on your system. This environment will have it’s own site-packages directory, etc., allowing you to avoid any type of library versioning issues across projects.

The mkvirtualenv command only needs to be executed once. To access the cv Python virtual environment after it has been created, just use the workon command:

$ workon cv

To validate that you are in the cv virtual environment, just examine your command line. If you see the text (cv) preceding the prompt, then you are are in the cv virtual environment:

Figure 6: Make sure you see the "(cv)" text on your prompt, indicating that you are in the cv virtual environment.
Figure 5: Make sure you see the “(cv)” text on your prompt, indicating that you are in the cv virtual environment.

Otherwise, if you do not see the cv text, then you are not in the cv virtual environment:

Figure 7: If you do not see the "(cv)" text on your prompt, then you are not in the cv virtual environment and you need to run the "workon" command to resolve this issue before continuing.
Figure 6: If you do not see the “(cv)” text on your prompt, then you are not in the cv virtual environment and you need to run the “workon” command to resolve this issue before continuing.

If you find yourself in this situation all you need to do is utilize the workon command mentioned above.

Install NumPy

The only Python-based prerequisite that OpenCV needs is NumPy, a scientific computing package.

To install NumPy into our cv virtual environment, ensure you are in the cv environment (otherwise NumPy will be installed into the system version of Python) and then utilize pip to handle the actual installation:

$ pip install numpy

Step #5: Install OpenCV prerequisites using Homebrew

OpenCV requires a few prerequisites to be installed before we compile it. These packages are related to either (1) tools used to build and compile, (2) libraries used for image I/O operations (i.e., loading various image file formats from disk such as JPEG, PNG, TIFF, etc.) or (3) optimization libraries.

To install these prerequisites for OpenCV on macOS execute the following commands:

$ brew install cmake pkg-config
$ brew install jpeg libpng libtiff openexr
$ brew install eigen tbb

Step #6: Download the OpenCV 3 source from GitHub

As I detailed in last week’s tutorial, OpenCV 3 on macOS needs to be compiled via the latest commit to GitHub instead of an actual tagged release (i.e., 3.0, 3.1, etc.). This is because the current tagged releases of OpenCV do not provide fixes for the QTKit vs. AVFoundation errors (please see last week’s blog post for a thorough discussion on this).

First, we need to download the OpenCV GitHub repo:

$ cd ~
$ git clone https://github.com/opencv/opencv

Followed by the opencv_contrib repo:

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

Step #7: Configure OpenCV and Python 3.5 via CMake on macOS

This section of the tutorial is the most challenging and the one that you’ll want to pay the most attention to.

First, I’ll demonstrate how to setup your build by creating the a build directory.

I then provide a CMake template that you can use to start the process of compiling OpenCV 3 with Python 3.5 bindings on macOS. This template requires you to fill in two values:

  1. The path to your libpython3.5.dylib file.
  2. The path to your Python.h headers for Python 3.5.

I will help you find and determine the correct values for these paths.

Finally, I provide a fully completed CMake command as an example. Please note that is command is specific to my machine. Your CMake command may be slightly different due to the paths specified. Please read the rest of this section for details.

Setting up the build

In order to compile OpenCV with Python 3.5 bindings for macOS we first need to set up the build. This simply amounts to changing directories and creating a build directory:

$ cd ~/opencv
$ mkdir build
$ cd build

OpenCV 3 + Python 3.5 CMake template for macOS

The next part, where we configure our actual build, gets a little tricky. In order to make this process easier I have constructed the following OpenCV 3 + Python 3.5 CMake template:

$ cmake -D CMAKE_BUILD_TYPE=RELEASE \
    -D CMAKE_INSTALL_PREFIX=/usr/local \
    -D OPENCV_EXTRA_MODULES_PATH=~/opencv_contrib/modules \
    -D PYTHON3_LIBRARY=YYY \
    -D PYTHON3_INCLUDE_DIR=ZZZ \
    -D PYTHON3_EXECUTABLE=$VIRTUAL_ENV/bin/python \
    -D BUILD_opencv_python2=OFF \
    -D BUILD_opencv_python3=ON \
    -D INSTALL_PYTHON_EXAMPLES=ON \
    -D INSTALL_C_EXAMPLES=OFF \
    -D BUILD_EXAMPLES=ON ..

Looking at this template I want to point out a few things to you:

  1. BUILD_opencv_python2=OFF : This switch indicates that we do not want to build Python 2.7 bindings. This needs to be explicity stated in the CMake command. Failure to do this can cause problems when we actually run CMake.
  2. BUILD_opencv_python3=ON : We would like for OpenCV 3 + Python 3.5 bindings to be built. This instruction indicates to CMake that the Python 3.5 binding should be built rather than Python 2.7.
  3. PYTHON3_LIBRARY=YYY : This is the first value that you need to fill in yourself. You need to replace YYY with the path to your libpython3.5.dylib file. I will hep you find the path to this value in the next section.
  4. PYTHON3_INCLUDE_DIR=ZZZ : This is the second value that you need to fill in. You will need to replace ZZZ with the path to your Python.h headers. Again, I will help you determine this path.

Determining your Python 3.5 library and include directory

We will start by configuring your PYTHON3_LIBRARY value. This switch should point to your libpython3.5.dylib file. This file is located within many nested subdirectories of /usr/local/Cellar/python . To find the exact path to the libpython3.5.dylib file, just use the ls command with a wildcard (auto-tab complete also works as well):

$ ls /usr/local/Cellar/python3/3.*/Frameworks/Python.framework/Versions/3.5/lib/python3.5/config-3.5m/libpython3.5.dylib
/usr/local/Cellar/python3/3.5.2_3/Frameworks/Python.framework/Versions/3.5/lib/python3.5/config-3.5m/libpython3.5.dylib

Take note of the output of this command — this is the full path to your libpython3.5.dylib file and will replace YYY in the CMake template above.

Let’s move along to determining the PYTHON3_INCLUDE_DIR variable. This path should point to the Python.h header files for Python 3.5 used to generate the actual OpenCV 3 + Python 3.5 bindings.

Again, we’ll use the same ls and wildcard trick here to determine the proper path:

$ ls -d /usr/local/Cellar/python3/3.*/Frameworks/Python.framework/Versions/3.5/include/python3.5m/
/usr/local/Cellar/python3/3.5.2_3/Frameworks/Python.framework/Versions/3.5/include/python3.5m/

The output of the ls -d command is our full path to the Python.h headers. This value will replace ZZZ in the CMake template.

Filling in the CMake template

Now that we’ve determined the PYTHON3_LIBRARY and PYTHON3_INCLUDE_DIR values we need to update the CMake command to reflect these paths.

On my machine, the full CMake command to configure my OpenCV 3 + Python 3.5 build looks like:

$ cmake -D CMAKE_BUILD_TYPE=RELEASE \
    -D CMAKE_INSTALL_PREFIX=/usr/local \
    -D OPENCV_EXTRA_MODULES_PATH=~/opencv_contrib/modules \
    -D PYTHON3_LIBRARY=/usr/local/Cellar/python3/3.5.2_3/Frameworks/Python.framework/Versions/3.5/lib/python3.5/config-3.5m/libpython3.5.dylib \
    -D PYTHON3_INCLUDE_DIR=/usr/local/Cellar/python3/3.5.2_3/Frameworks/Python.framework/Versions/3.5/include/python3.5m/ \
    -D PYTHON3_EXECUTABLE=$VIRTUAL_ENV/bin/python \
    -D BUILD_opencv_python2=OFF \
    -D BUILD_opencv_python3=ON \
    -D INSTALL_PYTHON_EXAMPLES=ON \
    -D INSTALL_C_EXAMPLES=OFF \
    -D BUILD_EXAMPLES=ON ..

However, please do not copy and paste my exact CMake command — make sure you have used the instructions above to properly determine your PYTHON3_LIBRARY and PYTHON3_INCLUDE_DIR values.

Once you’ve filled in these values, execute your cmake command and your OpenCV 3 + Python 3.5 build will be configured.

As an example, take a look at the Python 3 section output from my configuration:

Figure 7: Ensuring that Python 3.5 will be used when compiling OpenCV 3 for macOS.
Figure 7: Ensuring that Python 3.5 will be used when compiling OpenCV 3 for macOS.

In particular, you’ll want to make sure that:

  1. The Interpreter points to the Python binary in your cv virtual environment.
  2. Libraries points to your libpython3.5.dylib file.
  3. The numpy version being utilized is the one you installed in your cv virtual environment.

Step #8: Compile and install OpenCV 3 on macOS

After investigating your cmake command and ensuring it exited without error (and that the Python 3 section was properly configured), you can now compile OpenCV:

$ make -j4

In this case, I am supplying -j4 to compile OpenCV using all four cores on my machine. You can tune this value based on the number of processors/cores you have.

OpenCV can take awhile to compile, anywhere from 30-90 minutes, depending on your system specs. I would consider going for a nice long walk while it compiles.

A successful compile will end with a 100% completion:

Figure 9: Successfully compiling OpenCV 3 from source with Python 2.7 bindings on macOS.
Figure 8: Successfully compiling OpenCV 3 from source with Python 3.5 bindings on macOS.

Assuming that OpenCV compiled without error, you can now install it on your macOS system:

$ sudo make install

Step #9: Rename and sym-link your OpenCV 3 + Python 3.5 bindings

After running sudo make install your OpenCV 3 + Python 3.5 bindings should be located in /usr/local/lib/python3.5/site-packages . You can verify this by using the ls command:

$ cd /usr/local/lib/python3.5/site-packages/
$ ls -l *.so
-rwxr-xr-x  1 root  admin  3694564 Nov 15 11:28 cv2.cpython-35m-darwin.so

I’ve been perplexed by this behavior ever since OpenCV 3 was released, but for some reason, when compiling OpenCV with Python 3 support enabled the output cv2.so bindings are named differently. The actual filename will vary a bit depending on your system architecture, but it should look something like cv2.cpython-35m-darwin.so .

Again, I don’t know exactly why this happens, but it’s an easy fix. All we need to do is rename the file to cv2.so :

$ cd /usr/local/lib/python3.5/site-packages/
$ mv cv2.cpython-35m-darwin.so cv2.so
$ cd ~

After renaming cv2.cpython-35m-darwin.so to cv2.so we then need to sym-link our OpenCV bindings into the cv virtual environment for Python 3.5:

$ cd ~/.virtualenvs/cv/lib/python3.5/site-packages/
$ ln -s /usr/local/lib/python3.5/site-packages/cv2.so cv2.so
$ cd ~

Step #10: Verify your OpenCV 3 install on macOS

To verify that your OpenCV 3 + Python 3.5 installation on macOS is working you should:

  1. Open up a new terminal.
  2. Execute the workon command to access the cv Python virtual environment.
  3. Attempt to import the Python + OpenCV bindings.

Here are the exact steps you can use to test the install:

$ workon cv
$ python
Python 3.5.2 (default, Oct 11 2016, 04:59:56) 
[GCC 4.2.1 Compatible Apple LLVM 8.0.0 (clang-800.0.38)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import cv2
>>> cv2.__version__
'3.1.0-dev'
>>>

Note: Take note of the -dev  in the cv2.__version__ . This indicates that we are using the development version of OpenCV and not a tagged release. Once OpenCV 3.2 is released these instructions can be updated to simply download a .zip of the tagged version rather than having to clone down the entire repositories. 

I’ve also included a screenshot below that utilizes these same steps. As you can see, I can access my OpenCV 3 bindings from Python 3.5 shell:

Figure 9: Ensuring that I have successfully installed my OpenCV 3 + Python 3.5 bindings on macOS.
Figure 9: Ensuring that I have successfully installed my OpenCV 3 + Python 3.5 bindings on macOS.

Congratulations, you have installed OpenCV with Python 3.5 bindings on your macOS system!

So, what’s next?

Congrats! You now have a brand new, fresh install of OpenCV on your macOS system — and I’m sure you’re just itching to leverage your install to build some awesome computer vision apps…

…but I’m also willing to bet that you’re just getting started learning computer vision and OpenCV, and probably feeling a bit confused and overwhelmed on exactly where to start.

Personally, I’m a big fan of learning by example, so a good first step would be to have some fun and read this blog post on detecting cats in images/videos. This tutorial is meant to be very hands-on and demonstrate how you can (quickly) build a Python + OpenCV application to detect the presence of cats in images.

And if you’re really interested in leveling-up your computer vision skills, you should definitely check out my book, Practical Python and OpenCV + Case Studies. My book not only covers the basics of computer vision and image processing, but also teaches you how to solve real-world computer vision problems including face detection in images and video streams, object tracking in video, and handwriting recognition.

curious_about_cv

So, let’s put that fresh install of OpenCV 3 on your macOS system to good use

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Summary

In this tutorial you learned how to compile and install OpenCV 3 with Python 3.5 bindings on macOS Sierra.

To accomplish this, we configured and compiled OpenCV 3 by hand using the CMake utility. While this isn’t exactly the most “fun” experience, it does give us complete and total control over the install.

If you’re looking for an easier way to get OpenCV installed on your Mac system be sure to stay tuned for next week’s blog post where I demonstrate how to install OpenCV on macOS using nothing but Homebrew.

To be notified when this blog post goes live, please enter your email address in the form below and I’ll be sure to ping you when the tutorial is published.

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About the Author

Hi there, I’m Adrian Rosebrock, PhD. All too often I see developers, students, and researchers wasting their time, studying the wrong things, and generally struggling to get started with Computer Vision, Deep Learning, and OpenCV. I created this website to show you what I believe is the best possible way to get your start.

Reader Interactions

Previous Article:

macOS: Install OpenCV 3 and Python 2.7

Next Article:

Install OpenCV 3 on macOS with Homebrew (the easy way)

222 responses to: macOS: Install OpenCV 3 and Python 3.5

  1. Murtaza Dalal

    Hi adrian,
    I have a question regarding using c++ opencv. Are we supposed to have a separate virtual environment for that? What is the proper technique for installing and using c++ opencv on mac os Sierra? -the cake commands etc, as well as how to compile the c++ code for opencv. Do you think you could do a tutorial on that? Currently I’m just using c++ opencv on a virtual environment created from the python 2 tutorial and it works but I am not sure that I’m doing things correctly by using a python virtual environment for c++.

    • Adrian Rosebrock

      C++ doesn’t have a concept of a virtual environment in the same context as Python. This guide demonstrates how to use Python with OpenCV bindings, but natively OpenCV is a C++ library. You simply compile it, install it, and then use gcc/g++ to link against it when compiling your C++ code.

      • hareen tej

        hello sir, i followed your steps until i update the .bash_profile after installing virtualenv .
        before when i used the line pip install virtualenv virtualenvwrapper it didn’t worked as its saying some exceptions . but however i installed by using pip install –user virtualenv virtualenvwrapper.
        now when i source the ,bash_profile i get -bash: /usr/local/bin/virtualenvwrapper.sh: No such file or directory .
        and also whenever i quit the terminal and reopen it i get the above line in the 2nd line.

        • Adrian Rosebrock

          The reason you are getting the error each time you open a new terminal is because the ~/.bash_profile file is automatically loaded. Since virtualenv and virtualenvwrapper are not properly configured you are receiving the error.

          Which version of Python (2.7 or 3) are you installing OpenCV for?

  3. Malcolm Swan

    Hi Adrian,
    From Step #5 on are we supposed to be in the virtual environment (cv) as in Step #4? I’ve just completed Step #6 and realised that I’m still in the virtual environment. If we’re supposed to exit the virtual environment before moving onto Step #5 will deleting and recreating the virtual environment get me back on track?

    Thanks

    • Adrian Rosebrock

      Once you have entered the virtual environment you don’t need to leave it — you can stay inside it.

      If you ever need to access the virtual environment again, just use the workon command (don’t delete it and recreate it):

      $ workon your_virtual_env

  4. Tom Lorent Bourdo

    Hello, i have a problem during the step 7, my librairy isn’t having the right path as I stupidly used YYY and now can’t change it, do you have any idea of how could I get the path to my dylib file ?

    • Adrian Rosebrock

      Hey Tom — just delete your build directory, re-create it, and then re-run CMake with the correct path to your .dylib file.

  5. Jacob

    Thanks for this great tutorial! Everything worked well.

    What are the next steps to get OpenCV working in Pycharm 2016.3?

  6. Nick Machairas

    Hello Adrian, thank you for your thorough instructions. I followed your guide with the minor difference that for this specific application I did not want to work in a virtual environment. I made all necessary changes to PYTHON3_LIBRARY, PYTHON3_INCLUDE_DIR, PYTHON3_EXECUTABLE to point to the correct directories. What’s weird is that the `cv2.cpython-35m-darwin.so` was inside the OpenCV git repo instead of my local python site-packages folder. I renamed the .so file and placed it to the correct folder. This allows me to verify that opeCV is installed as in Step#10 above. I haven’t tested functionality yet, I’m about to start with one of your blog posts. I hope it will work.

    Thanks again!

    • Adrian Rosebrock

      Hey Nick — did you forget to run make install? It’s normal to see cv2.so in your build directory prior to actually running make install.

  7. Karen

    Thanks so much for your extremely helpful tutorial, I’ve been hoping you posted this blog for weeks! Just have one final question when I try to verify OpenCV 3 install on my macOS (Sierra), when I open up python3 IDLE and try to import cv2 function, I get error message “No module named CV2”. How do I go about using opencv3 module?

    • Adrian Rosebrock

      Are you using the terminal IDLE or the GUI IDLE? Keep in mind that the GUI version of IDLE does not respect Python virtual environments. You should be using the terminal IDLE instead (and from within the “cv” virtual environment).

      • Mansur

        Hello Adrian

        I am using the terminal IDLE from within the CV virtual environment and am getting the error “No Module named CV2”

        • Adrian Rosebrock

          IDLE and Python virtual environments are not compatible. Please use the Python shell from the command line or Jupyter Notebooks if you like the look and feel of IDLE.

  8. Heather

    Hi Adrian, thanks so much for creating this site!

    I attempted to follow these instructions exactly, including the part that describes how to construct the CMake command, but am having trouble using functions from opencv_contrib.

    For example:

    >>> import cv2
>>> help(cv2.xfeatures2d)
....
AttributeError: module 'cv2' has no attribute 'xfeatures2d'

    Any idea how to fix this?

    • Adrian Rosebrock

      Double check your OPENCV_EXTRA_MODULES_PATH — it looks like the path you supplied to CMake was incorrect.

      • Heather

        Thank you for your response. The path was correct — I checked it a couple times. I suspect the build may have not fully completed although I didn’t see any obvious error messages. In any case, I pulled the latest changes and rebuilt everything (using the exact same CMake command) and this time it worked.

      • Peter

        Hi, I just made it work.

        It seems my cmake can’t find opencv_contri unless I trail the path with a ‘/’ (OPENCV_EXTRA_MODULES_PATH=~/opencv_contrib/modules/). Make sense since it’s a folder but even the README.md on GitHub doesn’t do that.

        Also after ‘sudo make install’, the .so in ‘/usr/local/lib/python3.x/site-packages’ will be updated yet does not have any of the opencv_contri modules in it. However in the build folder a cv2.so just appeared and has all the opencv_contri things…

  9. Heather

    Adrian, one more issue that I’m having trouble troubleshooting: having trouble getting matplotlib to work with the virtual env set up described here. When I attempt “from matplotlib import pyplot as plt” I get:
    RuntimeError: Python is not installed as a framework. The Mac OS X backend will not be able to function correctly if Python is not installed as a framework. See the Python documentation for more information on installing Python as a framework on Mac OS X. Please either reinstall Python as a framework, or try one of the other backends. If you are Working with Matplotlib in a virtual enviroment see ‘Working with Matplotlib in Virtual environments’ in the Matplotlib FAQ

    I checked out the above doc but am still unsure how to proceed. Any pointers?

    I tried specifying “matplotlib.use(“TkAgg”)” and then I no longer get the RuntimeError from the import statement, but when I try to call a matplotlib function, I get:
    libc++abi.dylib: terminating with uncaught exception of type NSException
    Process finished with exit code 134 (interrupted by signal 6: SIGABRT)

    • Adrian Rosebrock

      This is an issue with matplotlib’s compatibility with Python virtual environments. I’m not sure when the issue will be resolved, but the easiest workaround is to simply install a previous version that is compatible with virtual environments:

      $ pip install matplotlib==1.4.3

      • Burak Karakan

        I can confirm that this is the exact solution to the issue. I tried various fixes, mostly related to the matplotlib backend engine fixes, but none of them solved the issue. Simply downgrading worked like a charm, thank you very much!

  11. chunwai

    Hi Adrian, I follow exactly the same steps but Terminal return (-bash: pip: command not found) when I try to install virtualenv and virtualenvwrapper by this command in step 4: pip install virtualenv virtualenvwrapper. However, if I use pip3, it works.

    • Adrian Rosebrock

      You can install virtualenv and virtualenvwrapper via pip3, that should work just fine. Although if you do, you might need to manually set the VIRTUALENVPATH. You should refer to the virtualenv and virtualenvwrapper documentation for more information on this.

      • Oliver Obst

        I also needed to set python3 for virtualenvwrapper, it is trying to use python otherwise.

        # Virtualenv/VirtualenvWrapper
        export VIRTUALENVWRAPPER_PYTHON=/usr/local/bin/python3

        • Adrian Rosebrock

          What do you mean by “manually” set it? You can use the “export” command as mentioned above.

    • Adrian Rosebrock

      Assuming you are in the build directory now, just go up one directory and use the rm -r command:

      $ cd ..
$ rm -r build

  14. Son Le

    If you encounter this error: “command not found: workon”, follow these steps:

    $ export WORKON_HOME=~/.virtualenvs
    $ VIRTUALENVWRAPPER_PYTHON=’/usr/bin/python3′ # or whenever your python3 is
    $ source /usr/local/bin/virtualenvwrapper.sh

  15. Jurgis

    Hey Adrian thanks for the tut,

    I was fiddling around for some time, carefully following your guide and everything would would until the Cmake part. it compiled everything correctly, but couldnt detect the python 3 libraries, so i went to the internet to search for alternative ways and found this website https://peekay.org/2016/03/24/opencv-osx-python-3-bindings/ and tried the authors code :

    cmake -D CMAKE_BUILD_TYPE=RELEASE \
 -D PYTHON3_EXECUTABLE=$(which python3) \
 -D PYTHON3_INCLUDE_DIR=$(python3 -c "from distutils.sysconfig import get_python_inc; print(get_python_inc())") \
 -D PYTHON3_LIBRARY=/usr/local/Cellar/python3/3.5.1/Frameworks/Python.framework/Versions/3.5/lib/libpython3.5.dylib \
 -D PYTHON3_LIBRARIES=/usr/local/Cellar/python3/3.5.1/Frameworks/Python.framework/Versions/3.5/bin \
 -D PYTHON3_INCLUDE_DIR=/usr/local/Cellar/python3/3.5.1/Frameworks/Python.framework/Versions/3.5/Headers \
 -D PYTHON3_PACKAGES_PATH=$(python3 -c "from distutils.sysconfig import get_python_lib; print(get_python_lib())") \
 -D INSTALL_C_EXAMPLES=OFF -D INSTALL_PYTHON_EXAMPLES=ON \
 -D BUILD_EXAMPLES=ON \
 -D OPENCV_EXTRA_MODULES_PATH=~/opencv_contrib/modules ..

    it seems to have worked and detected the python libraries, i’ll try finishing your tutorial and will see how it goes!

    Jurgis

  16. Anura

    Hi Adrian,

    By the time I was trying this tutorial, Python is in version 3.6. At Step 10 to verify OpenCV3 install, nothing appears after the command import cv2. Nothing appeared out of the ordinary in earlier steps. Any clue ?

    • Adrian Rosebrock

      What do you mean by “nothing appears after the command import cv2”? Does Python crash? Do you get an error message of some kind?

      • Anura

        Adrian,

        Apologies. My bad. It does work. I was expecting cv2.__version__ to be an output when in fact it was a command. When I checked…it’s at ‘3.2.0-dev’

  19. Victor

    Thanks for your tutorial! I think I managed to get it installed and am looking forward to follow the rest of your tutorials. Cheers!

  20. Mike

    I run as a non-admin user on OSX. Does this install work for that? I temporarily run as root in the terminal when setting things like this up, as you almost always need root access. After setting up as root, will everything work for my standard user account?

  21. Tadhg Riordan

    Can confirm working for python 3.6 with some slight directory changes for the cmake command. Thank you! 🙂

    • Adrian Rosebrock

      This tutorial will work with Python 3.6 as long as you update the CMake command to point to your Python 3.6 files.

  22. Tom Lorent Bourdo

    Hey, do you have any ideas on how could I do to link my python openCV with anaconda not to work with the console anymore ? thanks for the great work !

    • Adrian Rosebrock

      You would need to create a new “build” directory, create a Python virtual environment for Python 3, run CMake, compile OpenCV, and then move the cv2.so file into your site-packages directory.

  24. Chandramauli Kaushik

    Thank you so much, I finally got OpenCV with python3.6.
    Great page and tutorials.
    Thanks :)))

  25. Nome

    Thanks for the great tutorial! I followed it and was able to get OpenCV working, until I encountered a strange error. I had been able to use VideoCapture no problem until I recently transferred everything over to a new hard drive. I copied over everything so it should ostensibly work the same. However, now OpenCV is unable to use VideoCapture and returns error: (-215). It sounds like it could be a ffmpeg issue, but any ideas how to fix it if I followed your installation tutorial?

    Thanks!

    • Adrian Rosebrock

      Are you trying to compile and install OpenCV without a virtual environment? Or access the OpenCV bindings from outside the virtual environment?

      • Tarun

        I was able to install opencv in cv virtual environment successfully. However, i’d like to be able to import cv2 outside the specific virtual environment, in spyder or jupter notebook. How do I go about doing that? Thank you so much for your assitance.

        • Adrian Rosebrock

          Did you install the cv2.so file into the global site-packages for Python? If so, just install NumPy outside the virtual environment via $ sudo pip install numpy and you should be able to import OpenCV outside the Python virtual environment.

  27. Marko

    Hi, thanks. Couple of questions:

    1. At the end of step 7, you say, “As an example, take a look at the Python 3 section output from my configuration:” – what is the command to access these config settings?

    2. In what directory do I run the “make -j4” command?

    • Adrian Rosebrock

      1. Take a look at the output of “CMake”.

      2. You should run the make -j4 command in the build directory after CMake has (successfully) ran.

  28. Antonios

    Hi Adrian.
    In order to follow your way of working with Python & OpenCV on my MAC,
    on step 2 – I installed & builded the nano text editor.
    Then , you say “Save & exitor the editor followed by source …”.
    My question is how to save ?
    In case that I press (cmd + S), it will guide me to Save a something.txt file in the Documents file.

    K.R.
    Antonios

  29. Antonios

    Hi Adrian.
    On step8 – you type $ make -j4, in order to run for all 4 cores,
    but in my case I have 2 core system. Should I run $ make -j2 ?

    K.R.
    Antonios

  30. Antonios Kats

    Hi Adrian, thank you very much for this tutorial.
    I completed it and I’m so happy about it. I’ d like to ask you what would be the next step.
    I tried to create a new python file by texting $ nano whatever.py (in the cv environment from the step#10, but didn’t work. I need your help 😉

    • Adrian Rosebrock

      I’m not sure what you mean by “it didn’t work”. Did you receive an error message of some kind?

      • Antonios Kats

        I just needed to install scipy in the working environment (cv).
        Thanks for the help !

  31. Sjoerd

    Ok, so first of all: thnx for this amazing tutorial and the time you obviously devoted to it!

    For me the worst challenge was to get OpenCV installed for my native python3.4 install on macOS 10.12.3 (there is a tutorial for this on your website as well, but it uses Homebrew which in turn automatically installs Python3.6 while I really need 3.4 for other reasons). But anyways, got that solved.

    Then some small adaptions where needed but those are already mentioned in the earlier comments.

    One thing though: when applying your code to my own dataset a lot of the ‘results’ where to big to display on my screen, so only parts of them where visible. I solved this by changing the last few lines of code in search.py to:

    for (score, resultID) in results:
    # load the result image and display it
    cv2.namedWindow(‘Result’,cv2.WINDOW_NORMAL)
    result = cv2.imread(args[“result_path”] + “/” + resultID)
    resultresized = cv2.resize(result, (600,600))
    cv2.imshow(“Result”, resultresized)
    cv2.waitKey(0)

    This will allow you to resize the outfit to fit your screen. I used 600 by 600 pixels as an example but off course one could also write a function to downscale the output to a minimum size while maintaining the original proportions.

    • Adrian Rosebrock

      Thanks for the comment Sjoerd. Out of curiosity, which images were you trying to display that were too big to display to your screen? I normally try to keep the result images smaller for this reason.

  32. Thibault

    Hi,
    I installed it on 3.6
    I used the following cmake and it worked properly. you have to adjust it with your setup eventually. 

    cmake -D CMAKE_BUILD_TYPE=RELEASE \
 -D PYTHON3_EXECUTABLE=$(which python3) \
 -D PYTHON3_INCLUDE_DIR=$(python3 -c "from distutils.sysconfig import get_python_inc; print(get_python_inc())") \
 -D PYTHON3_LIBRARY=/usr/local/Cellar/python3/3.6.0/Frameworks/Python.framework/Versions/3.6/lib/python3.6/config-3.6m-darwin/libpython3.6.dylib \
 -D PYTHON3_LIBRARIES=/usr/local/Cellar/python3/3.6.0/Frameworks/Python.framework/Versions/3.6/bin \
 -D PYTHON3_INCLUDE_DIR=/usr/local/Cellar/python3/3.6.0/Frameworks/Python.framework/Versions/3.6/Headers \
 -D PYTHON3_PACKAGES_PATH=$(python3 -c "from distutils.sysconfig import get_python_lib; print(get_python_lib())") \
 -D INSTALL_C_EXAMPLES=OFF -D INSTALL_PYTHON_EXAMPLES=ON \
 -D BUILD_EXAMPLES=ON \
 -D OPENCV_EXTRA_MODULES_PATH=~/opencv_contrib/modules ..

    it worked well.
    The cv2.so file actually was installed directly in the virtual env with the name: cv2.cpython-36m-darwin.so
    ~/.virtualenvs/cv/lib/python3.6/site-packages

    • Misha

      Wow your version worked on my Mac with 3.6 as well, while Adrian’s failed(

      Thank you so much, Thibault!!!

      • Adrian Rosebrock

        Thank you for sharing Thibault and Misha! I will create another tutorial for Python 3.6 + OpenCV 3 in the future.

        • hendrick

          hi adrian
          I failed when install python 3.6 + opencv 3 with fatal error.
          do you have tutorials for this

          thank you

  33. nick

    Awesome!!

    but I just come across two question…
    1, I don’t have a python file in the Cellar (I used my own python3.5 without using homebrew) .
    2, after cmake, the config is succesufll but the Python3’s libraries parts show YYY rather than a path…

    Can you help me fix it? Thanks a lot!

  34. Jonny Taylor

    Hi,

    Thanks for writing this tutorial. For future reference, a note about what I needed to do (Anaconda python 3 on OS X 10.9.5):

    When building with the tagged 3.2.0 build I encountered the following error during the ‘make’ phase:

    In file included from /Volumes/Development/opencv/modules/core/src/hal_internal.cpp:49:
    /Volumes/Development/opencv/build/opencv_lapack.h:1:10: fatal error: ‘CBLAS_H_PATH-NOTFOUND/Accelerate/Accelerate.h’ file not found
    #include “CBLAS_H_PATH-NOTFOUND/Accelerate/Accelerate.h”

    I could not see any obvious error at the cmake stage (output here http://pastebin.com/3Qc8kYVV).

    Instead, I tried building against the latest ‘master’ build for opencv and opencv_contrib (3.2.0-332-gc1007c7). When doing this, I encountered the following problem (https://github.com/opencv/opencv/issues/8129); the instruction to disable freetype solved that problem and I was able to compile successfully.

  35. Lakshman

    hi,
    I completed the installation, and the cv2.so file is copied to /Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages as cv2.so. When i try to use the package by using import cv2, it is giving

    import cv2
    ImportError: dynamic module does not define module export function (PyInit_cv2)

    Please help me out, how to resolve the issue

    Environment and OS details below
    OS: macOs – 10.11.6
    Python: 3.5

    • Adrian Rosebrock

      It sounds like CMake might have compiled OpenCV with Python 2.7 support rather than Python 3. Go back to the CMake step and check which bindings are being compiled.

  36. Ellery

    I get this warning when I run brew linkapps. Should I be worried?

    —

    $ brew linkapps python3
    Warning: `brew linkapps` has been deprecated and will eventually be removed!
    …

  38. Mohamad

    Hey Adrian,

    I followed your instructions but there is a problem with my Cmake output. When it’s finished, I checked the python3 libraries path and it haven’t found the library’s path. As the below:
    Python 3:
    — Interpreter: /usr/local/bin/python3 (ver 3.6.1)
    — Libraries: NO
    — numpy: /usr/local/lib/python3.6/site-packages/numpy/core/include (ver 1.12.0)
    — packages path: /usr/local/lib/python3.6/site-packages

    After that, when I run make -j8 , it gives me errors. How can I solve it?

    • Adrian Rosebrock

      Either your PYTHON3_LIBRARY or PYTHON3_INCLUDE_DIR is incorrect. Double-check them per the instructions I have included in this guide.

  39. Yash

    Hello Adrian,

    When I am trying to use the command ‘make-j4’ command, I get this error.

    “make: *** No targets specified and no makefile found. Stop.”

    What can I do??

    • Adrian Rosebrock

      Your CMake command likely exited with an error. Go back to the CMake step, look for the error, and then resolve it. The CMake command is used to generate the Makefile required to build OpenCV.

  40. Alkasm

    Woohoo! I got it working with OpenCV 3.2.0 on Python 3.6.1.

    This was my cmake command:

    cmake -D CMAKE_BUILD_TYPE=RELEASE \
     -D PYTHON3_EXECUTABLE=$(which python3) \
     -D PYTHON3_INCLUDE_DIR=$(python3 -c "from distutils.sysconfig import get_python_inc; print(get_python_inc())") \
     -D PYTHON3_LIBRARY=/usr/local/Cellar/python3/3.6.1/Frameworks/Python.framework/Versions/3.6/lib/ \
     -D PYTHON3_LIBRARIES=/usr/local/Cellar/python3/3.6.1/Frameworks/Python.framework/Versions/3.6/bin \
     -D PYTHON3_INCLUDE_DIR=/usr/local/Cellar/python3/3.6.1/Frameworks/Python.framework/Versions/3.6/Headers \
     -D PYTHON3_PACKAGES_PATH=$(python3 -c "from distutils.sysconfig import get_python_lib; print(get_python_lib())") \
     -D INSTALL_C_EXAMPLES=OFF -D INSTALL_PYTHON_EXAMPLES=ON \
     -D BUILD_EXAMPLES=ON \
     -D OPENCV_EXTRA_MODULES_PATH=~/opencv_contrib/modules ..

    One step that was different in my case. I did the cmake and install step while I was still in the (cv) virtual environment and the .so file was already installed in ~/.virtualenvs/… so all I had to do was browse to there and rename it as shown.

    Thanks, this tutorial was excellent and taught me a lot in the process!

    • Berthy

      How exactly did you get this to work, Alkasm? I followed all the steps of the tutorial up until the cmake portion and instead borrowed from your commands. However, here’s a snippet of the output I’m getting:

      Python 3:
      Interpreter: /Users/leitan/.virtualenvs/cv/bin/python3 (ver 3.6)

      And that’s the only line for Python 3. It still couldn’t find the PythonLibs. What is it that I’m doing differently?

  41. LawSky

    Thank u !!!!
    I’m a Chinese student, It’s every hard for me to login and say something to u
    but it much easier than set up opencv on my computer !!!!
    All I want u to know is u are a good teacher, I’ll share this blog with my classmates.

  42. Jose

    Hi Adrian, many thanks for your great quality posts, I have been following several of them and learning a lot!

    I wanted to pass here some of my experience in the installation process:

    1. The first problem I faced was the inability of cmake to download the correct icv file. After some time downloading, it interrupted the process saying the file downloaded was different from the one expected. I searched around and found out that this is due to cmake being built with an old curl version, installed by default in the mac, that doesn’t support ssl. But using brew would install the newer ssl-supporting curl version only as a keg, not linked. Therefore you have to link it manually to /usr/local/ carefully, all the files in the folders include/, lib/ and bin/.
    After doing this liking I removed and re-installed cmake, and this time it could download the correct icv file. And everything went right 🙂 …

    2. Except that when using the cv2 library inside my cv environment and I executed cv2.imshow for example (I was following your cat faces tutorial) it did not open any gui window. I wonder what options has to be passed to cmake to enable gui?

    3. I also followed your post of installing ocv3 using brew directly, and again this time when using imshow there was a reply of “init done opengl support available” but not gui window opens. I made sure to install gtk, qt, etc. But something is wrong in my arguments to cmake probably?

    Best,

    • Adrian Rosebrock

      Hi Jose — regarding cv2.imshow you need to place a call to cv2.waitKey(0) immediately after in order to display the image to your screen.

  43. Rajat Parajuli

    Hey Adrain. So I just completed your tutorial and installed opencv 3.2 successfully, or so I thought. So when I try to display an image with Im show all I get is the title bar of the window. I have even posted it on stack overflow with no avail. Here’s the link to my question/problem on stackoverflow.
    https://stackoverflow.com/questions/44228407

    I tried imread and imwrite they however, seem to work.

    • Adrian Rosebrock

      That is indeed some strange behavior. Can you do print(image.shape) and let me know the output? It seems for some strange reason that OpenCV isn’t loading your BMP image.

  44. Nyng

    I’ve successfully installed OpenCV 3.2.0-dev with python 3.6.1 by following your tutorial!
    Should I delete ~/opencv and ~/opencv_contrib after all these steps? Thanks!

    • Adrian Rosebrock

      Yes, once OpenCV has been successfully installed you can delete the opencv and opencv_contrib directories.

  45. Ram

    Thanks for the tutorial. I am successfully able to compile and install openCV. I am suing Qt creator to write application. but I want to debug and step through the openCV source code. I like to know how to do it ? is there any instructions? Please let me know. Thanks

    • Adrian Rosebrock

      It really depends on your IDE. My main suggestion would be to use PyCharm which has a lot of built-in tools for this type of debugging.

  46. yichen

    Thanks for this fantastic tutorial, I followed everything in this tutorial and they worked perfectly. I just bought your book practical python and opencv. And trying to test the code given, however, cv2.imshow() function doesn’t seem to work anywhere, it’s only showing the top bar, not event a black or grey background, just a topbar. Please help, currently, i have to use imwrite function to check if my codes are working correctly.

    Versions:
    OpenCV: The current github version, at June 16 2017. Which i’ve got no idea how to check the version code.
    And Python 3.6.1

  47. Andrew

    Quick question: Where do I put my C-make template? I’m at Step 7, and I’m confuse because I don’t see where do I put my Cmake template or how to execute it.

  48. Fohlen

    Actually now there is a homebrew formular in homebrew/science
    Just

    “`
    brew tap homebrew/science
    brew install opencv3
    ““

    or `brew install –with-python3`

    nevertheless, nice tutorial!

  49. Vaidehi

    After running the cmake command, in the python3 section I get the following:

    Python 3:
    — Interpreter: NO

    How do I fix this?

    • Adrian Rosebrock

      Make sure you are in the “cv” virtual environment and that you properly created the Python virtual environment using the -p python3 switch. From there, delete your “build” directory, re-recreate it, and re-run CMake.

  50. Jonah Rosenblatt

    Thank you so much Adrian for this insightful guide. I have been trying to install OpenCV for about a week, but am encountering the same problems. Virtualenvwrapper, for some reason, is not recognized, and neither is the dylib file, which is cannot be found. How do I fix this?

    • Adrian Rosebrock

      Hi Jonah — it’s hard to say what the exact problem is. I would run pip freeze to verify that both virtualenv and virtualenvwrapper have been properly installed. Also double check that your ~/.bash_profile file was updated correctly.

  51. Sumith

    Hi Adrian, I used your tutorial to install opencv-3.2.0-dev with python 3.6. I am using it on mac os sierra. I used opencv to read and show the image. But I am getting a window created but nothing is getting displayed in that window it’s blank.

    Below is my code :
    import cv2

    cv2.namedWindow(‘image’)
    result = cv2.imread(‘/Users/sumithkrishna/1.jpg’)
    cv2.imshow(‘image’, result)
    cv2.waitKey(0)

    Am i getting it wrong somewhere.

    • Adrian Rosebrock

      This is actually a known issue with the current development edition of OpenCV and macOS — the GUI/window functionality will not work. You will need to use the tagged 3.0, 3.1, or 3.2 release for macOS until the issue is resolved.

  53. Thierry

    Hi,

    thank you for all. I do not understand all the commands made 😉 but it works fine.
    Just a remark, concerning the use of “pip”. On my MacBook Pro late 2015 I was in front of a problem solved by the url below. There was a trouble on the command “pip install virtualenv virtualenvwrapper”. An installed version is failing the previous command. The solution is to use the “–ignore-installed six” option.

    Regards, and thanks again.

    https://stackoverflow.com/questions/33185147/on-os-x-el-capitan-i-can-not-upgrade-a-python-package-dependent-on-the-six-compa

  54. Anthony

    Hi Adrian,

    I’ve reached Step 10 but when I type in the command “import cv2”, the output is
    “Traceback (most recent call last): File “”, line 1, in ModuleNotFoundError: No module named ‘cv2′”.

    Could this be related to the Step 7’s input? If so, is the fix to delete the build and start from the build directory again?

    Thanks.

    • Adrian Rosebrock

      Hi Anthony — there are a variety of reasons why the “cv2” module may not be found. Are you in the “cv” virtual environment? Did you double-check your CMake output to ensure that the “python3” module was in the list of modules to be compiled?

  55. Andrew Baker

    Last night I was able to work through the tutorial successfully with the latest versions of Python 3.6.2 and openCV 3.3.

    My setup:
    MacOS Sierra 10.12.6
    Xcode 8.3.3
    Command Line Tools (Xcode 8.2). It is very important you downgrade the CLT. The current version of the CLT does not support CUDA 8.0.61. If you don’t do this you will not successfully build.

    NVCC 8.0.61
    clang 800.0.42.1 -> comes with the install of CLT from 8.2

    The build will take a long time ( > 1 hour). It will unexpectedly pause, mine did around 87%. Be patient. Do not abruptly end this build. It will finish.

  56. Francesco Renzi

    Hi! Thanks for the precious tutorial, it really helped a lot. Everything works great, aside from the fact the importing cv2 only works from a python console started within the folder where cv2.so is. Is there any way to make it accessible globally?

    • Adrian Rosebrock

      Hi Francesco — congrats on getting OpenCV installed. You should be able to access the cv2 bindings anywhere on your system as long as you are in the “cv” virtual environment. It sounds like you may have missed the sym-link step and/or you are not in the “cv” virtual environment.

  57. Vijay Krishna B

    Unable to use pip.
    Getting error pip: command not found
    Tried this approach to install pip but not working
    1.sudo easy_install pip
    python get-pip.py

  58. Sahil Goyal

    Whenever I run ‘source ~/.bash_profile’ after installing virtualenv and virtualenvwrapper following error comes.
    ERROR:-
    /usr/bin/python: No module named virtualenvwrapper
    virtualenvwrapper.sh: There was a problem running the initialization hooks.

    If Python could not import the module virtualenvwrapper.hook_loader,
    check that virtualenvwrapper has been installed for
    VIRTUALENVWRAPPER_PYTHON=/usr/bin/python and that PATH is
    set properly.

    Could you please help ?

      • Sahil Goyal

        I was able to install OpenCV 3.3 and it is running fine. But I want to ask how to use Xcode to write code for python.

        • Adrian Rosebrock

          I would suggest explicitly setting your VIRTUALENVWRAPPER_PYTHON inside your .bash_profile, like this:

          # virtualenv and virtualenvwrapper
export VIRTUALENVWRAPPER_PYTHON=/usr/local/bin/python3
source /usr/local/bin/virtualenvwrapper.sh

  59. anas sinjab

    hello Adrian
    thanks a lot for ur help

    but i have a problem with Step #4: Install Python virtual environments and NumPy

    after i downloded both and add
    # Virtualenv/VirtualenvWrapper
    source /usr/local/bin/virtualenvwrapper.sh

    and run source ~/.bash_profile
    it gives me -bash: /usr/local/bin/virtualenvwrapper.sh: No such file or directory
    any suggestion ?

    • Adrian Rosebrock

      Which Python version are you trying to use when installing OpenCV? Python 2.7? Or Python 3?

      • anas sinjab

        i have both python on my system but i wanna use 3.6.2

        the problem above has been solvd somwhow
        but when i go to next step
        $ mkvirtualenv cv -p python3
        i get
        ERROR: virtualenvwrapper could not find virtualenv in your path
        any idea ??

  61. opcode

    Thanks for the awesome instructions! I followed them on OSX Sierra with python 3.6.3 and got an error during the build, Python.h not found. I discovered that ../modules/python/common.cmake includes “${${PYTHON}_INCLUDE_PATH}” whereas the cmake prototype you provide has …INCLUDE_DIR. I added one more line to the cmake command
    -D PYTHON3_INCLUDE_PATH=/usr/local/Cellar/python3//3.6.3/Frameworks/Python.framework/Versions/3.6/include/python3.6m/ \
    which was the path in my case, reran cmake and make, and it built cleanly.

  62. Sahil

    I have installed Opencv 3 and I am using it with python for about month. But I want to try it with C++ (with Xcode) now, so what should I do to use the previously installed version of opencv 3. I am using macOS high sierra and Xcode 9.

  63. Brian

    Hi Adrian,
    After running the cmake command, my terminal shows the result that “Libraries: NO” inside “Python 3”. How can I solve it? Thank you

    • Adrian Rosebrock

      Hi Brian — can you confirm you are inside the “cv” virtual environment before run “cmake”? Secondly, I put together a self-configuring CMake command in this blog post. I would suggest you give that a try as well.

  64. David Hoffman

    If you run into the following issue:

    $ sudo xcodebuild -license accept
    xcode-select: error: tool 'xcodebuild' requires Xcode, but active developer directory '/Library/Developer/CommandLineTools' is a command line tools instance

    …while accepting the XCode License, here is the solution:

    $ sudo xcode-select -s /Applications/Xcode.app/Contents/Developer
    $ sudo xcodebuild -license accept

  65. Dinesh

    I just have a quick question. Still a newbie here. So, I followed all the steps and got the cv2.so. When I do workon cv and I try importing cv, I must have the cv2.so file inside the particular folder I am working in. Maybe I missed a commentary somewhere but is that normal? So for example, if I switch to d folder inside My Document and try import cv2, it would not work until I copy over the cv2.so file inside. Again, sorry if I missed anything but again, is this normal? Thank you.

    • Adrian Rosebrock

      This is not normal and is likely due to missing the sym-link step in Step 9. Go back to Step 9 and ensure the sym-link is created from your cv2.so file to the “site-packages” directory of your Python virtual environment. Once the sym-link is created you’ll be able to import your OpenCV bindings regardless of which directory you are in.

  66. Kiran

    Was successfully able to install OpenCV 3.3.1-dev, python-3.6.3 on my Mac OS X Sierra. Here is my CMake File.

    cmake -D CMAKE_BUILD_TYPE=RELEASE \
    -D CMAKE_INSTALL_PREFIX=/usr/local \
    -D OPENCV_EXTRA_MODULES_PATH=~/opencv_contrib/modules \
    -D PYTHON3_LIBRARY=/usr/local/Cellar/python3/3.6.3/Frameworks/Python.framework/Versions/3.6/lib/python3.6/config-3.6m-darwin/libpython3.6.dylib \
    -D PYTHON3_INCLUDE_DIR=/usr/local/Cellar/python3/3.6.3/Frameworks/Python.framework/Versions/3.6/include/python3.6m/ \
    -D PYTHON3_EXECUTABLE=$VIRTUAL_ENV/bin/python \
    -D BUILD_opencv_python2=OFF \
    -D BUILD_opencv_python3=ON \
    -D INSTALL_PYTHON_EXAMPLES=ON \
    -D INSTALL_C_EXAMPLES=OFF \
    -D BUILD_EXAMPLES=ON ..

    And rest of the steps as mentioned by our beloved and true hero, Adrian!

    Cheers 🙂

    • Adrian Rosebrock

      Thanks for sharing, Kiran! And congratulations on getting OpenCV installed on your macOS machine 🙂

    • Chad

      Are you using High Sierra? I verified that my PYTHON3_INCLUDE_DIR and PYTHON3_LIBRARY are identical to yours, but I still get the following errors:

      — Python 3:
      — Interpreter: /Users/admin/.virtualenvs/cv/bin/python (ver 3.6.3)
      — Libraries: NO
      — numpy: NO (Python3 wrappers can not be generated)
      — packages path: /Users/admin/.virtualenvs/cv/lib/python3.6/site-packages
      — Python (for build): /Users/admin/.virtualenvs/cv/bin/python

    • Adrian Rosebrock

      This is due to a recent update with Homebrew. My suggestion would be to use the “python2” and “python3” commands directly instead of trying to alias the “python” commands. If you do:

      $ which python2
$ which python3

      You will get the correct output.

  68. Jessie Free

    Hello Adrian,
    Thanks for a great tutorial. I’m having trouble in step 7 when I try to find the python library. The include directory returns a path but the python library
    ls /usr/local/Cellar/python3/3.*/Frameworks/Python.framework/Versions/3.6/lib/python3.6/config-3.6m/libpython3.6.dylib returns “no such file or directory”. As a result, once I execute the cmake command, I get “NO” for libraries. Any thoughts on what might be going wrong? Thanks in advance.

  69. kaisar khatak

    Good post. I am up and running with opencv 3.4.0-dev in a python3 virtual environment on MacOS Sierra 10.12.6. It looks like opencv can open and render images. I might try the
    “brew install opencv3” method in the future for practice…

    PYTHON TEST SCRIPT:
    import cv2
    img = cv2.imread(“/Users/datadude/Downloads/some-image.jpg”)
    cv2.imshow(“img”,img)
    cv2.waitKey(0)

    ———————————

    CMAKE Command:

    cmake -DCMAKE_BUILD_TYPE=RELEASE \
    -DCMAKE_INSTALL_PREFIX=/usr/local \
    -DOPENCV_EXTRA_MODULES_PATH=~/opencv_contrib/modules \
    -DPYTHON3_LIBRARY=/usr/local/Cellar/python3/3.6.4/Frameworks/Python.framework/Versions/3.6/lib/python3.6/config-3.6m-darwin/libpython3.6.dylib \
    -DPYTHON3_INCLUDE_DIR=/usr/local/Cellar/python3/3.6.4/Frameworks/Python.framework/Versions/3.6/include/python3.6m \
    -DPYTHON3_EXECUTABLE=$VIRTUAL_ENV/bin/python \
    -DBUILD_opencv_python2=OFF \
    -DBUILD_opencv_python3=ON \
    -DINSTALL_PYTHON_EXAMPLES=ON \
    -DINSTALL_C_EXAMPLES=OFF \
    -DBUILD_EXAMPLES=ON ..

  71. Deven Reilly

    Hey Adrian 🙂 I need ffmpeg but it never seems to be included. I’ve been following the instructions but every time I use Cmake it spits this out:

    — Video I/O:
    — DC1394: NO
    — FFMPEG: NO
    — avcodec: NO
    — avformat: NO
    — avutil: NO
    — swscale: NO
    — avresample: NO
    — GStreamer: NO
    — AVFoundation: YES
    — gPhoto2: NO

    How can I include it in the build? Thanks in advance.

  72. Bryan

    Hey Adrian,

    I was trying to install this on my macOS, but it was not working by giving my PythonLibs not found whenever I would follow the path “/usr/local/Cellar…/libpython3.6m.dylib” but when I changed it to /Library/Frameworks…/libpython3.6m.dylib” it worked. Is this alright? I got the path of my library from sys.path.

  73. Ghazal Sahebzamani

    Hey Adrian,
    Thanks for your detailed tutorial. Unfortunately, when I run the CMake command, it exits with errors. By opening the error log, I assume C++ 11 isn’t supported on my system although I have Xcode installed. I also tried installing gcc, but that seemed quite a challenge as well !
    I also tried forcing Cmake to use C++ 11 by running this commands:
    set(CMAKE_CXX_STANDARD 11)
    but I get “syntax error near unexpected token `CMAKE_CXX_STANDARD”
    Any idea what I should do?
    BTW I’m using high sierra (10.13.2)
    Thanks in advance.

    • Adrian Rosebrock

      The error message seems to imply that you have an old version of gcc installed, although that wouldn’t make sense if you’re using the latest Xcode and High Sierra. What is the output of:

      $ gcc --version

  74. AJNahas

    Hey Adrian,

    I really appreciate this amazing tutorial. However, I have been encountering many errors – even after searching online, using pip3 and python3 for the latest versions, making sure every detail is correct, repeating everything over 7 times by uninstalling and installing homebrew – but to no avail.

    May I ask that you please create a new tutorial based on the new python 3.6 and mac HighSierra? I, as well as many, would really appreciate that.

    Thanks again.

  75. Aashish

    During this command

    — make -j4

    facing this issue

    till this point everything installed correctly.

    /Users/aashish-mac/opencv/modules/python/src2/cv2.cpp:7:10: fatal error: ‘Python.h’ file not found

    • Adrian Rosebrock

      For whatever reason it looks like the Python headers are not installed on your system. Did you install both Xcode and Homebrew?

      • Romain C

        Hi, I have this problem yet xcode and homebrew are installed

        xcode :

        Xcode 9.3
        Build version 9E145

        homebrew :

        Homebrew 1.5.14
        Homebrew/homebrew-core (git revision 1f9b; last commit 2018-04-07)

        Thanks for your help

  76. Vish

    I can’t thank you enough! best wishes dude! you made my day. that moment when I sew import cv2 work on Mac!!!

    • Adrian Rosebrock

      Congrats on getting OpenCV installed on your macOS machine, Vish! Great job 🙂

  77. Michael Zhang

    Hi Adrian,

    I’m new to OpenCV and get stuck at step #7… When I do “ls -d /usr/local/Cellar/python3/3.*/Frameworks/Python.framework/Versions/3.5/include/python3.5m/”, it prompts “No such file or directory”.

    So I cd into “/usr/local/Cellar/”, and found that there is only folder name “python” but no “python3”. Inside of “python” folder, there are 3.6.4_4 and 3.6.5.

    I did install python3 using brew. So how can I find the right path to libpython3.5.dylib?

    Thanks,
    Michael

    • Adrian Rosebrock

      I’m not sure which one would be your Python 3 install. Try using “3.6.4_4” and if the “Python 3” section of “cmake” is not correctly filled out then go back and use “3.6.5”.

      • Joep Truijen

        Hi Adrian, Im new.

        I run into the same problem but continued with /python/ instead of /Python3/. I filled out “cmake” like this:

        YYY

        /usr/local/Cellar/python/3.6.5/Frameworks/Python.framework/Versions/3.6/lib/python3.6/config-3.6m-darwin/libpython3.6.dylib

        ZZZ

        /usr/local/Cellar/python/3.6.5/Frameworkds/Python.framework/Versions/3.6/include/python3.6m/ \

        By doing so the python 3 section output from the configuration from (Figure 7) did not show the section python 2 and python 3, instead it showed Python (for build): /usr/local/bin/python2.7

        Because it listed:
        — Configuring done
        — Generating done,

        I continued until step #9 were I used the ls -l command in site-packages folder because there is no file named cv2.cpython-35m-darwin.so in it. Nothing like it.

        (I hope this is clear information rather than to much of it)

        Could really use your advice because I feel like I was so close :p

        Thanks,
        Joep

        • Adrian Rosebrock

          Ignore the “Python (for build)” section — it’s buggy. Instead, just ensure your “Python 3” section is correctly filled out. Also, check your “build/lib” directory after you finish running “make”. Your OpenCV bindings should be in that directory.

          A last suggestion would be to check your output from “cmake”, in particular the list of modules to be compiled. You should see “python3” listed as one of the modules.

          • Joep Truijen

            Thank you, it worked, I think the problem was that with python3.6.5 you have to fill in the cmake command with:

            -D PYTHON3_EXECUTABLE=/usr/local/bin/python3 \

            Instead of:

            -D PYTHON3_EXECUTABLE=/usr/local/bin/python \

            Thank you for your work! its great!

          • Joep Truijen

            can’t remember if I replied or not, but it worked! Don’t know if it was a typo or filling out the cmake “-D PYTHON3_EXECUTABLE= ” section with

            /usr/local/bin/python3 \

            as Greg Pierce suggested below, instead of

            /usr/local/bin/python \

            Thanks allot I already got my hands on some Average face scripts for my graduation project!

          • Adrian Rosebrock

            Congrats on resolving the issue, Joep! And best of luck with your graduation project.

  78. Jerome Guibert

    Thanks for your article,

    Let’s go to image processing on mac, and pi, and ..

    🙂

  79. Greg Pierce

    Just in case someone was trying to do this on a Python 3.6.5 install with the latest OpenCV 3.4.1

    cmake -D CMAKE_BUILD_TYPE=RELEASE \
    -D CMAKE_INSTALL_PREFIX=/usr/local \
    -D OPENCV_EXTRA_MODULES_PATH=/projects/opencv_contrib/modules \
    -D PYTHON3_LIBRARY=/usr/local/Cellar/python3/3.6.5/Frameworks/Python.framework/Versions/3.6/lib/python3.6/config-3.6m-darwin/libpython3.6.dylib \
    -D PYTHON3_INCLUDE_DIR=/usr/local/Cellar/python3/3.6.5/Frameworks/Python.framework/Versions/3.6/Headers/ \
    -D PYTHON3_EXECUTABLE=/usr/local/bin/python3 \
    -D BUILD_opencv_python2=OFF \
    -D BUILD_opencv_python3=ON \
    -D INSTALL_PYTHON_EXAMPLES=ON \
    -D INSTALL_C_EXAMPLES=OFF \
    -D BUILD_EXAMPLES=ON ..

    Note, this build is done to support building inside and outside of virualenvs

  81. Roshan Sivakumar

    Hi,

    This is the warning i got when I was installing python3

    Warning: python 3.6.5 is already installed, it’s just not linked
    You can use `brew link python` to link this version.

    Should I link it and why?

    • Adrian Rosebrock

      It sounds like you already have Python 3 installed. Run:

      $ which python3

      To check the path (as we do in the blog post) to ensure it’s the Homebrew install vs. the system install of Python.

  82. Gaurav Didwania

    Hey Adrian, I have followed your tutorial but in the last step i am having trouble.
    the ln command gives
    ln: cv2.so: File exists
    This I know is because i tries the installation once before with some error so the file from previous time exist.
    How should I remove it.

  83. Ryan

    Hi Adrian,

    I’m having an issue with Step #4.

    Since I’m using python 3 (stored in: /usr/local/bin/python3), I installed pip via: `python3 get-pip.py` (note: using “python3”), and therefore I only have pip3 on my machine (not pip). In step #4 when I run `pip3 install virtualenv virtualenvwrapper`, it successfully downloads, but virtualenv appears to gets stored in: /usr/local/lib/python3.7/site-packages, NOT /usr/local/bin.

    As a result, when I add `source /usr/local/bin/virtualenvwrapper.sh` to my bash_profile it fails when I then source the bash_profile:

    “-bash: /usr/local/bin/virtualenvwrapper.sh: No such file or directory”

    Do you have any recommendations on this?

    Thanks!

    • Ryan

      UPDATE: I noticed that when I run `sudo find / -name virtualenvwrapper.sh` it tells me that the shell script is saved here:

      /usr/local/Cellar/python/3.7.0/Frameworks/Python.framework/Versions/3.7/bin/virtualenvwrapper.sh

      any thoughts why this is not in the same dir as yours (/usr/local/bin)?

      Thanks!

      • Adrian Rosebrock

        Hey Ryan — check you check your .bash_profile file? If you add the following line to your virtualenv section:

        export VIRTUALENVWRAPPER_PYTHON=/usr/local/bin/python3

        It should work. Secondly, keep in mind the “bin” directory is for binaries and the “lib” directory is for “libraries” so your directory structure makes sense.

  84. Sarthak Dandriyal

    Adrian I am facing a problem with “Determining your Python 3.5 library and include directory”
    I have installed python 3.7 and it is showing no directory found.
    please help.

  85. Bill Harvey

    Mmm everything seemed to be going OK until after step 9 I checked to see if it all worked.
    I can enter my virtual environment in terminal by using ‘workon cv’, when I enter python it returns python 3.7.1, but when I try to import cv2 I get the error Traceback (most recent call last):
    File “”, line 1, in
    ModuleNotFoundError: No module named ‘cv2’

    Symlink seemed to work OK?

    Mac OS X High Sierra Python 3.7.1

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