My Pi 3 Install Log (5): OpenCV (part 1) on Raspberry Jessie (Lite)

$ apt-get upgrade

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## now play with OpenCV ##

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(main resource from pyimagesearch) http://www.pyimagesearch.com/2016/04/18/install-guide-raspberry-pi-3-raspbian-jessie-opencv-3/

Title: opencv w/ python bindings

## step 1 expand file system (no need)

## step 2 dependencies

# dev tools

(no need, already have) $ sudo apt-get install build-essential cmake pkg-config

# image I/O packages

$ sudo apt-get install libjpeg-dev libtiff5-dev libjasper-dev libpng12-dev

# video I/O packages

$ sudo apt-get install libavcodec-dev libavformat-dev libswscale-dev libv4l-dev

$ sudo apt-get install libxvidcore-dev libx264-dev

# Opencv has a sub-module highgui, for display image and basic GUI, has dependency on gtk2.0 (crap! Download 20.6MB->60.x)

$ sudo apt-get install libgtk2.0-dev

# matrix operations needs a few optimization libraries, which are important on resource constrained devices like Pi. (dl 9MB->45MB)

$ sudo apt-get install libatlas-base-dev gfortran

# python 2.7 and 3 header files for opencv w/ python bindings(dl 44->70MB)

$ sudo apt-get install python2.7-dev python3-dev

## step 3: opencv source 3.1 (first 3.x stable version) 76MB

# main source

$ cd ~

$ wget -O opencv.zip https://github.com/Itseez/opencv/archive/3.1.0.zip

$ unzip opencv.zip

# need features such as SIFT and SURF, so opencv_contrib (52.6MB)

$ wget -O opencv_contrib.zip https://github.com/Itseez/opencv_contrib/archive/3.1.0.zip

$ unzip opencv_contrib.zip

# install ‘pip’, a Python package manager

$ wget https://bootstrap.pypa.io/get-pip.py

$ sudo python get-pip.py

## step 4: python

# virtualenv and virtualenvwrapper

$ sudo pip install virtualenv virtualenvwrapper

$ sudo rm -rf ~/.cache/pip

# ‘df -h’ now 3.8G (27%) used

# append to ~/.profile

# virtualenv and virtualenvwrapper

export WORKON_HOME=$HOME/.virtualenvs

source /usr/local/bin/virtualenvwrapper.sh

# now take effect

$ source ~/.profile

## next to do creating your python virtual environment

# 2.7 or 3  ??

# I did:
$ mkvirtualenv cv -p python2

-- to be continue .. --