OpenCV3 & Python3 environment construction on Ubuntu

Environment construction on Ubuntu

The standard package is only for Python2, so prepare it yourself. There seems to be a problem with cmake's Python 3.4 detection process, and it didn't work very well, so I'll make a note of it as a reminder.

Target environment

• cmake can't get the path of python3 library and target opencv_python3 becomes unavailable
• (Maybe ubuntu14.04 can't detect python3)

It was relatively easy to do in a windows environment, but I never thought it would be so hard on Ubuntu.

Preparation

Install the required packages

Referenced site Installer Opencv 3 sur Ubuntu 14.04 Trusty (It's not English, but I understand it as it is)

sudo apt install libopencv-dev build-essential checkinstall cmake pkg-config yasm libtiff4-dev libjpeg-dev libjasper-dev \
libavcodec-dev libavformat-dev libswscale-dev libdc1394-22-dev libxine-dev libgstreamer0.10-dev libgstreamer-plugins-base0.10-dev \
libv4l-dev python3-dev python3-numpy libtbb-dev libqt4-dev libgtk2.0-dev libfaac-dev libmp3lame-dev \
libopencore-amrnb-dev libopencore-amrwb-dev libtheora-dev libvorbis-dev libxvidcore-dev x264 v4l-utils python3.4-dev

Copy pyconfig.h

I don't know if I need it

sudo cp /usr/include/python3.4m/pyconfig.h /usr/include/python3.4m/pyconfig.h_old
sudo cp /usr/include/i386-linux-gnu/python3.4m/pyconfig.h /usr/include/python3.4m/

Edit cmake file

I don't know that cmake has 3.4 in python version, so I'll tell you. FindPython{Interp,Libs}: Search for Python 3.4. The edit target is

• Modules/FindPythonInterp.cmake
• Modules/FindPythonLibs.cmake There are two.

Get the source code

git clone https://github.com/Itseez/opencv.git

cmake Set various options with cmake-gui In my environment, I got an error because the hash of the file is different, so I had to set WITH_IPP = OFF.

Detect Python libraries

• python not found (cmake log)

Found PythonInterp: /usr/bin/python2.7 (found suitable version "2.7.6", minimum required is "2.7") 
Could NOT find PythonLibs (missing:  PYTHON_INCLUDE_DIRS) (found suitable exact version "2.7.6")
Found PythonInterp: /usr/bin/python3.4 (found suitable version "3.4", minimum required is "3.4") 
Could NOT find PythonLibs (missing:  PYTHON_LIBRARIES) (Required is exact version "3.4.0")

• Select the Python, Python2, Python3 path entry and click Remove Entory to remove
• Press Configure again
• python found (cmake log)

Found PythonInterp: /usr/bin/python2.7 (found suitable version "2.7.6", minimum required is "2.7") 
Found PythonLibs: /usr/lib/x86_64-linux-gnu/libpython2.7.so (found suitable exact version "2.7.6") 
Found PythonInterp: /usr/bin/python3.4 (found suitable version "3.4", minimum required is "3.4") 
Found PythonLibs: /usr/lib/x86_64-linux-gnu/libpython3.4m.so (found suitable exact version "3.4.0")

• Create Makefile with Generate as it is (If you press Configure, the entries for the paths of Python, Python2, and Python3 will be restored, so if you press Configure again in this state, it will revert to the missing state)

make Once you have a Makefile, there should be no problem after that.

make -j4
sudo make install