I installed OpenCV-Python on my Raspberry Pi

Overview

Anyway, I want to install OpenCV safely, so I installed it by the official method. https://docs.opencv.org/master/d2/de6/tutorial_py_setup_in_ubuntu.html

environment

hard

Raspberry Pi 3 B+

OS

$ cat /etc/debian_version
10.7

$ cat /etc/os-release 
PRETTY_NAME="Raspbian GNU/Linux 10 (buster)"
NAME="Raspbian GNU/Linux"
VERSION_ID="10"
VERSION="10 (buster)"
VERSION_CODENAME=buster
ID=raspbian
ID_LIKE=debian
HOME_URL="http://www.raspbian.org/"
SUPPORT_URL="http://www.raspbian.org/RaspbianForums"
BUG_REPORT_URL="http://www.raspbian.org/RaspbianBugs"

Installation

$ sudo apt-get install python-opencv

Actually, this is all it takes.

>>> import cv2
>>> print(cv2.__version__)
4.5.1-dev

Installation was successful with Python2.

However, with Python3,

>>> import cv2
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ModuleNotFoundError: No module named 'cv2’
>>> 

I can't find it.

I can't find the cv2.so file when I try to pass it, so I will try to build from the source.

Building OpenCV from source

Install necessary packages for the time being

First, install them as needed for the build.

sudo apt-get install cmake
sudo apt-get install gcc g++

I want both Python2 and 3

sudo apt-get install python-dev python-numpy
sudo apt-get install python3-dev python3-numpy

Install GTK related What is GTK? .. .. → It seems to be used when making a GUI application.

sudo apt-get install libavcodec-dev libavformat-dev libswscale-dev
sudo apt-get install libgstreamer-plugins-base1.0-dev libgstreamer1.0-dev
sudo apt-get install libgtk2.0-dev
sudo apt-get install libgtk-3-dev

For the time being, it seems that you can build up to this point. The next one seems to just update the package in reserve.

Preliminary installation (no need to do)

sudo apt-get install libpng-dev
sudo apt-get install libjpeg-dev
sudo apt-get install libopenexr-dev
sudo apt-get install libtiff-dev
sudo apt-get install libwebp-dev

Download OpenCV

Download it from Git.

$ sudo apt-get install git
$ git clone https://github.com/opencv/opencv.git

It was long. Create a build directory. The name is build for the time being

$ cd opencv
$ mkdir build
$ cd build

Installation

Next is the installation.

cmake ../

It is near the end of the output.

--   Python 2:
--     Interpreter:                 /usr/bin/python2.7 (ver 2.7.16)
--     Libraries:                   /usr/lib/arm-linux-gnueabihf/libpython2.7.so (ver 2.7.16)
--     numpy:                       /usr/lib/python2.7/dist-packages/numpy/core/include (ver 1.16.2)
--     install path:                lib/python2.7/dist-packages/cv2/python-2.7
-- 
--   Python 3:
--     Interpreter:                 /usr/bin/python3 (ver 3.7.3)
--     Libraries:                   /usr/lib/arm-linux-gnueabihf/libpython3.7m.so (ver 3.7.3)
--     numpy:                       /usr/lib/python3/dist-packages/numpy/core/include (ver 1.16.2)
--     install path:                lib/python3.7/dist-packages/cv2/python-3.7

It's convenient to be able to configure the installation with just this. I will study again what is happening.

Finally, build and install.

$ make
# sudo make install

It took a lot of time. About 5 hours I don't want to do it anymore! !! !! !! !! !! !!

Verification

$ python3
>>> import cv2
>>> print(cv2.__version__)
4.5.1-dev

did it!

Finally

I've done it properly, so I've updated OpenCV to the latest dev version. It's ** super annoying ** because I have to build again to change the version.

Everyone be careful.