最近使用yolov5做项目，但是在安装pycocotools和opencv的时候却遇到了麻烦，始终报错。尝试了网上的各种解决办法都无解，历时一下午终于解决了这个头疼的问题。

问题

首先建立了yolov5的虚拟环境，然后切换到yolov5环境下，根据官方源码的requirements.txt文件安装依赖关系。

(yolov5) C:\Research\landslide\code\yolov5\yolov5-master>pip install -r C:\Research\landslide\code\yolov5\yolov5-master\requirements.txt

一杯茶结束后，发现报错，然后 conda list列出所有包和requirements.txt中的要求对比，发现少了pycocotools和opencv-python两个包。然后再次执行下面的代码都报错。

pip install pycocotools
pip install opencv-python

分别报错信息如下：

WARNING: Retrying (Retry(total=4, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError(SSLEOFError(8, 'EOF occurred in violation of protocol (_ssl.c:1125)'))': /simple/pycocotools/
WARNING: Retrying (Retry(total=3, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError(SSLEOFError(8, 'EOF occurred in violation of protocol (_ssl.c:1125)'))': /simple/pycocotools/
WARNING: Retrying (Retry(total=2, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError(SSLEOFError(8, 'EOF occurred in violation of protocol (_ssl.c:1125)'))': /simple/pycocotools/
WARNING: Retrying (Retry(total=1, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError(SSLEOFError(8, 'EOF occurred in violation of protocol (_ssl.c:1125)'))': /simple/pycocotools/
WARNING: Retrying (Retry(total=0, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError(SSLEOFError(8, 'EOF occurred in violation of protocol (_ssl.c:1125)'))': /simple/pycocotools/
Could not fetch URL https://pypi.org/simple/pycocotools/: There was a problem confirming the ssl certificate: HTTPSConnectionPool(host='pypi.org', port=443): Max retries exceeded with url: /simple/pycocotools/ (Caused by SSLError(SSLEOFError(8, 'EOF occurred in violation of protocol (_ssl.c:1125)'))) - skipping
ERROR: Could not find a version that satisfies the requirement pycocotools
ERROR: No matching distribution found for pycocotools

WARNING: Retrying (Retry(total=4, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError(SSLEOFError(8, 'EOF occurred in violation of protocol (_ssl.c:1125)'))': /simple/opencv-python/
WARNING: Retrying (Retry(total=3, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError(SSLEOFError(8, 'EOF occurred in violation of protocol (_ssl.c:1125)'))': /simple/opencv-python/
WARNING: Retrying (Retry(total=2, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError(SSLEOFError(8, 'EOF occurred in violation of protocol (_ssl.c:1125)'))': /simple/opencv-python/
WARNING: Retrying (Retry(total=1, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError(SSLEOFError(8, 'EOF occurred in violation of protocol (_ssl.c:1125)'))': /simple/opencv-python/
WARNING: Retrying (Retry(total=0, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError(SSLEOFError(8, 'EOF occurred in violation of protocol (_ssl.c:1125)'))': /simple/opencv-python/
Could not fetch URL https://pypi.org/simple/opencv-python/: There was a problem confirming the ssl certificate: HTTPSConnectionPool(host='pypi.org', port=443): Max retries exceeded with url: /simple/opencv-python/ (Caused by SSLError(SSLEOFError(8, 'EOF occurred in violation of protocol (_ssl.c:1125)'))) - skipping
ERROR: Could not find a version that satisfies the requirement opencv-python
ERROR: No matching distribution found for opencv-python

最后找到的解决办法就是，到对应的官网去下载.whl文件包，然后指定路径安装就可以

opencv的安装

下载安装包

到oencv官网下载对应的.whl文件(opencv官网下载地址)
根据自己的python和电脑操作系统版本下载对应的包，我下载的是：

opencv_python-4.4.0-cp38-cp38-win_amd64.whl

opencv_python-4.4.0：opencv版本号
cp38-cp38：环境中python的版本号
win_amd64：windows64位操作系统

放置到对应的环境中

将下载好的.whl放置到anaconda目录下的yolov5环境中的site-packages文件下下，比如我放置在

安装opencv

最后再次安装opencv

(yolov5) C:\Research\landslide\code\yolov5\yolov5-master>pip install C:\Users\40809\anaconda3\envs\yolov5\Lib\site-packages\opencv_python-4.4.0-cp38-cp38-win_amd64.whl

提示如下即为安装成功

Processing c:\users\40809\anaconda3\envs\yolov5\lib\site-packages\opencv_python-4.4.0-cp38-cp38-win_amd64.whl
Installing collected packages: opencv-python
Successfully installed opencv-python-4.4.0

安装pycocotools

安装方法和安装opencv一样，包下载地址(pycocotools下载地址)。

安装完成后运行 conda list即可看到已经全部安装成功。