What is this?

Limitations

Tested with Ubuntu 16.04 and nothing else

• Only with opencv-git-head, and OpenCV-3.3.0
• I have no need to make it work with other configurations.

What is this?

It is a collection of scripts used to create working "OpenCV" virtual environments using Python. It is greatly modeled, or flavored after Adrian Rosebrock's "PyImageSearch" work but with a few differences.

a. I am not using his virtual machine - I'm using my linux box

b. Adrian's instructions BUILDS & INSTALLS OpenCV into a standard place

In contrast, I specify point the CMAKE_INSTALL_PREFIX at the virtual enviroment, thus OpenCV is installed into Virtual Environment and not a standard place.

Main reason: Why? Because this lets me have multiple (N=many) versions of OpenCV at the same time that do not conflict with each other, and quickly switch between different versions - for example Shell Window (A) - is for v3.3, but shell window (B) is for git-head (See conclusion for more details)

Secondary: In addition, Adrian's solutions (tutorials) generally install some Python things into the Python Virtual Environment. An example of this is Numpy, which Adrian installs via 'pip' - in contrast I install Numpy (and many other packages) via 'apt-get install' or via "pip install" but I install them into the standard system wide locations. Perhaps that is a dumb move - but it works for me.

Scripts are, and are used like this:

Install various Ubuntu packages via "apt-get"

Install various packages via "apt-get" This appears to be the list of things you need to enable "lots of stuff" in opencv the list may be incomplete and/or overkill - but seems to be what I needed.

Note: This may not install everything you need, and may over install stuff your milage may vary.

   $ bash ./setup_scripts/setup_apt_get.sh

Python Packages via PIP

Install/upgrade pip

   $ bash ./setup_scripts/setup_pip.sh

Install packages, again: "Your milage may vary"

   $ bash ./setup_scripts/setup_pip_packages.sh

Fetching Source Code

from GIT, ie: HEAD

   $ bash ./setup_scripts/clone_opencv.sh

Or - download a specific release version of OpenCV from github

Step 1 - Fetch tarballs (ie: A release number)

   $ OPENCV_VERSION=3.3.0 bash ./setup_scripts/fetch_opencv.sh

Step 2 - Unpack the tarballs

   $ OPENCV_VERSION=3.3.0 bash ./setup_scripts/untargz_opencv.sh

Creating a virtual environment

You can just type the command like below.

An important thing to remember here - Many of the Ubuntu Python-ish packages are installed in the directory: /usr/local/lib/pythonVERSION - by default that package is disabled and ignored in the virtual environment. This is by design

The problem you come across is this:

• You want to use OpenCV - in a VirtualEnv
• Good: You can install some things in the VirtualEnv -
  • This is nice.. and helpful
• Bad: But other things ... you cannot install intot he VirtualEnv
  • Well that sucks - and it becomes a blocking problem.
  • And you cannot for various other reasons fix this

you are now stuck - you have GOOD thing and a BAD thing

The solution is actually quite simple, just enable: "--system-site-packages"

    $ mkvirtualenv NAMEHERE --system-site-packages -p python3

Or use the script

    $ bash ./setup_scripts/make_env.sh  NAMEHERE
	
    # Enable the env
    $ workon foobar
	
    # ... hack hack hack...
    # once you are done...
	
    # Disable the environment
    $ disable foobar

Building

Requires and demands a python virtual environment. Why? Because the OpenCV build is installed into virtual env..

# By default, "head" is used.
$ bash setup_scripts/build_opencv.sh

Or set the ENV varible: OPENCV_VERSION on the command line

$ OPENCV_VERSION=3.3.0 bash setup_scripts/build_opencv.sh

Or, or as a variable and export it

$ OPENCV_VERSION=3.3.0
$ export OPENCV_VERSION
$ bash setup_scripts/build_opencv.sh

So what's this give me?

$ workon  cv_head

# I can now use Python with OpenCV Head

Then in another shell window

$ bash ./setup_scritps/make_env.sh experiment1
$ workon experiment1

# Hack OpenCV make changes, learn the code
# could be OpenCV 3.3 or Head it does not matter.

$ bash ./setup_script/build_opencv.sh

# Test and experiment with my hacked opencv

Meanwhile - my installed opencv-head is intact and not mucked with.

When I'm done with the experiment I just delete the virtual environment.