みんな大好きOpenCV。
今回は、OpenCVを Python3 on RasPi3B+ な環境に突っ込んでみます。
(ただし、諸事情によりOpenCVは最新版でなく3.4系を入れます)
実際のところ
sudo apt update sudo apt autoremove sudo apt upgrade -y sudo reboot
$ sudo apt-get install libhdf5-dev libhdf5-serial-dev libhdf5-dev $ sudo apt-get install libqtgui4 libqtwebkit4 libqt4-test python3-pyqt5 $ sudo apt-get install libatlas-base-dev $ sudo apt-get install libjasper-dev $ sudo apt-get install python3-opencv
opencv は諸事情により3系の最新版を導入。
執筆時点では4.1系があるので、マトモな事情の人は最新版をいれませう
$ pip3 install opencv-contrib-python==3.4.7.28
試しに読み込めてるか確認。
$ python3 Python 3.7.3 (default, Dec 20 2019, 18:57:59) [GCC 8.3.0] on linux Type "help", "copyright", "credits" or "license" for more information. >>> import cv2 >>> cv.__version__ Traceback (most recent call last): File "<stdin>", line 1, in <module> NameError: name 'cv' is not defined >>> cv2.__version__ '3.4.7'
ビルド？？
opencv-contrib-python · PyPI
によると
Q: Pip fails with Could not find a version that satisfies the requirement ...?
A: Most likely the issue is related to too old pip and can be fixed by running pip install --upgrade pip. Note that the wheel (especially manylinux) format does not currently support properly ARM architecture so there are no packages for ARM based platforms in PyPI. However, opencv-python packages for Raspberry Pi can be found from https://www.piwheels.org/.
とあり、ARMの実装はPC用より対応バージョンが遅れることがある模様。
$ pip3 install opencv-contrib-python==3.4.9.31 WARNING: pip is being invoked by an old script wrapper. This will fail in a future version of pip. Please see https://github.com/pypa/pip/issues/5599 for advice on fixing the underlying issue. To avoid this problem you can invoke Python with '-m pip' instead of running pip directly. Defaulting to user installation because normal site-packages is not writeable Looking in indexes: https://pypi.org/simple, https://www.piwheels.org/simple ERROR: Could not find a version that satisfies the requirement opencv-contrib-python==3.4.9.31 (from versions: 3.4.2.16, 3.4.2.17, 3.4.3.18, 3.4.4.19, 3.4.6.27, 3.4.7.28, 4.0.1.24, 4.1.0.25, 4.1.1.26) ERROR: No matching distribution found for opencv-contrib-python==3.4.9.31
参考もと
Raspberry Pi + Python 3 に OpenCV 3 をなるべく簡単にインストールする - Qiita
https://devtalk.nvidia.com/default/topic/1051160/jetson-nano/install-opencv-for-python3-in-jetson-nano/
piwheels - opencv-contrib-python
ラズパイでpython3にopencvを入れたらエラーが出た【対処法】 - Qiita
*1:libhdf5-100とか書いてあるところがありますが、多分態々バージョン指定しなくともdev突っ込んだ方が無難です
