OpenCV is an open-source Python library, which used to understand the content of the digital image. The CV is the abbreviation form of computer vision. It extracts the description from the real-time image or digital image, which may be an object, a text description, and so on.
We can perform many tasks using the OpenCV library such as face detection, face recognition, blob detection, edge-detection, image filter, template matching, and etc. To work with the OpenCV, we need to install it in our Python environment.
Installation of OpenCV
Here, we install the OpenCV using the following ways.
- Using pip command
- Using Anaconda
Using pip command
Open a command prompt and type the following command.
Or, we can install it without extra module by the following command.
Now, we will verify the proper installation of OpenCV. Import the cv2 module and print its version.
If it has properly installed, then it will show its version.
Using Anaconda
Anaconda is a software package of Python. Anaconda with Jupyter is a the best way to work with the OpenCV. First, we need to install the Anaconda graphics installer from its official site.
Now, choose a suitable bit installer.
Once download is completed. Open the Anaconda prompt and type the following command.
Then, hit the enter button and it will download all rated OpenCV configuration.
Now, we are ready to work with the OpenCV. You can learn complete OpenCV through our OpenCV tutorial (//www.javatpoint.com/opencv).
Goals
In this tutorial
- We will learn to setup OpenCV-Python in your Windows system.
Below steps are tested in a Windows 7-64 bit machine with Visual Studio 2010 and Visual Studio 2012. The screenshots shows VS2012.
Installing OpenCV from prebuilt binaries
- Below Python packages are to be downloaded and installed to their default locations.
- Python 3.x (3.4+) or Python 2.7.x from here.
- Numpy package (for example, using pip install numpy command).
- Matplotlib (pip install matplotlib) (Matplotlib is optional, but recommended since we use it a lot in our tutorials).
- Install all packages into their default locations. Python will be installed to C:/Python27/ in case of Python 2.7.
- After installation, open Python IDLE. Enter import numpy and make sure Numpy is working fine.
- Download latest OpenCV release from GitHub or SourceForge site and double-click to extract it.
- Goto opencv/build/python/2.7 folder.
- Copy cv2.pyd to C:/Python27/lib/site-packages.
- Open Python IDLE and type following codes in Python terminal.
>>> import cv2 as cv
>>> print( cv.__version__ )
If the results are printed out without any errors, congratulations !!! You have installed OpenCV-Python successfully.
Building OpenCV from source
- Download and install Visual Studio and CMake.
- Visual Studio 2012
- CMake
Download and install necessary Python packages to their default locations
- Python
- Numpy
- Make sure Python and Numpy are working fine.
- Download OpenCV source. It can be from Sourceforge (for official release version) or from Github (for latest source).
- Extract it to a folder, opencv and create a new folder build in it.
- Open CMake-gui (Start > All Programs > CMake-gui)
- Fill the fields as follows (see the image below):
- Click on Browse Source... and locate the opencv folder.
- Click on Browse Build... and locate the build folder we created.
Click on Configure.
image
It will open a new window to select the compiler. Choose appropriate compiler (here, Visual Studio 11) and click Finish.
image
- Wait until analysis is finished.
You will see all the fields are marked in red. Click on the WITH field to expand it. It decides what extra features you need. So mark appropriate fields. See the below image:
image
Now click on BUILD field to expand it. First few fields configure the build method. See the below image:
image
Remaining fields specify what modules are to be built. Since GPU modules are not yet supported by OpenCV-Python, you can completely avoid it to save time (But if you work with them, keep it there). See the image below:
image
Now click on ENABLE field to expand it. Make sure ENABLE_SOLUTION_FOLDERS is unchecked (Solution folders are not supported by Visual Studio Express edition). See the image below:
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Also make sure that in the PYTHON field, everything is filled. (Ignore PYTHON_DEBUG_LIBRARY). See image below:
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- Finally click the Generate button.
- Now go to our opencv/build folder. There you will find OpenCV.sln file. Open it with Visual Studio.
- Check build mode as Release instead of Debug.
- In the solution explorer, right-click on the Solution (or ALL_BUILD) and build it. It will take some time to finish.
Again, right-click on INSTALL and build it. Now OpenCV-Python will be installed.
image
- Open Python IDLE and enter 'import cv2 as cv'. If no error, it is installed correctly.
Additional Resources
Exercises
If you have a windows machine, compile the OpenCV from source. Do all kinds of hacks. If you meet any problem, visit OpenCV forum and explain your problem.