前言
我在使用pip install opencv-python 时报错
Could not find a version that satisfies the requirement opencv (from versions: ) No matching distribution found for opencv*
树莓派的镜像是默认装的镜像，没怎么装过其他东西的。我查看了python的版本，python是2.7版本的，树莓派镜像默认是装好了python2。分析原因，python2版本过旧，无法找到满足opencv需求的版本。然后我将python3安装，发现opencv安装成功。
具体操作
1.执行 sudo apt-get install python3 命令安装python3
sudo apt-get install python3
2.执行 python3 -V 查看 python3是否安装成功
python3 -V
3.执行 pip3 install opencv-python
pip3 install opencv-python
安装好后如图
4.执行 pip3 list 验证 pip3中是否安装了opencv-python
pip3 list
5.进入python3 执行 import cv2 as cv 查看opencv-python 是否成功安装进python3
python3
import cv2 as cv
此时出现了个坑，报错：ImportError:libcblas.so.3:cannot open shared object file:No such file or directory
这个报错的意思是没有安装libcblas的库，此时安装Blas 的依赖项就解决了。安装libcblas库的命令是：
sudo apt-get install libatlas-base-dev
sudo apt-get install libatlas-base-dev
或
sudo apt-get install libgflags-dev
sudo apt-get install libgoodle-glog-dev
sudo apt-get install liblmdb-dev
sudo apt-get install python
sudo apt-get install python-dev
sudo apt-get install python-numpy
sudo apt-get install ipython
sudo apt-get install ipython-notebook
sudo apt-get install python-sklearn
sudo apt-get install python-skimage
sudo apt-get install python-protobuf
sudo apt-get install libgflags-dev
sudo apt-get install libgoodle-glog-dev
sudo apt-get install liblmdb-dev
sudo apt-get install python
sudo apt-get install python-dev
sudo apt-get install python-numpy
sudo apt-get install ipython
sudo apt-get install ipython-notebook
sudo apt-get install python-sklearn
sudo apt-get install python-skimage
sudo apt-get install python-protobuf
这里演示 命令sudo apt-get install libatlas-base-dev
6.再次进入python3 执行 import cv2 as cv 查看opencv-python 是否成功安装进python3
（若第五步遇到坑则执行第六步）
