1.pycocotools库的简介

pycocotools即python api tools of COCO。COCO是一个大型的图像数据集，用于目标检测、分割、人的关键点检测、素材分割和标题生成。这个包提供了Matlab、Python和luaapi，这些api有助于在COCO中加载、解析和可视化注释。请访问COCO – Common Objects in Context，可以了解关于COCO的更多信息，包括数据、论文和教程。COCO网站上也描述了注释的确切格式。Matlab和PythonAPI是完整的，LuaAPI只提供基本功能。

2.pycocotools安装的坑

今天我在跑超轻量目标检测模型NanoDet时，遇到了各种各样的问题，其中卡住最久的就是pycocotools的安装，整整花费了我数小时。我出现了以下的报错

执行: python -m pip install pycocotools时

ERROR: Command errored out with exit status 1:
command: 'D:\Anaconda3\python.exe' -u -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'C:\\Users\\46653\\AppData\\Local\\Temp\\pip-install-j33342g5\\pycocotools\\setup.py'"'"'; __file__='"'"'C:\\Users\\46653\\AppData\\Local\\Temp\\pip-install-j33342g5\\pycocotools\\setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' bdist_wheel -d 'C:\Users\46653\AppData\Local\Temp\pip-wheel-0xpeseyp' --python-tag cp37
cwd: C:\Users\46653\AppData\Local\Temp\pip-install-j33342g5\pycocotools\
Complete output (13 lines):
running bdist_wheel
running build
running build_py
creating build
creating build\lib.win-amd64-3.7
creating build\lib.win-amd64-3.7\pycocotools
copying pycocotools\coco.py -> build\lib.win-amd64-3.7\pycocotools
copying pycocotools\cocoeval.py -> build\lib.win-amd64-3.7\pycocotools
copying pycocotools\mask.py -> build\lib.win-amd64-3.7\pycocotools
copying pycocotools\__init__.py -> build\lib.win-amd64-3.7\pycocotools
running build_ext
building 'pycocotools._mask' extension
error: Microsoft Visual C++ 14.0 is required. Get it with "Build Tools for Visual Studio": https://visualstudio.microsoft.com/downloads/
----------------------------------------
ERROR: Failed building wheel for pycocotools
ERROR: Command errored out with exit status 1:
command: 'D:\Anaconda3\python.exe' -u -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'C:\\Users\\46653\\AppData\\Local\\Temp\\pip-install-j33342g5\\pycocotools\\setup.py'"'"'; __file__='"'"'C:\\Users\\46653\\AppData\\Local\\Temp\\pip-install-j33342g5\\pycocotools\\setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' install --record 'C:\Users\46653\AppData\Local\Temp\pip-record-ucmhdqzv\install-record.txt' --single-version-externally-managed --compile
cwd: C:\Users\46653\AppData\Local\Temp\pip-install-j33342g5\pycocotools\
Complete output (13 lines):
running install
running build
running build_py
creating build
creating build\lib.win-amd64-3.7
creating build\lib.win-amd64-3.7\pycocotools
copying pycocotools\coco.py -> build\lib.win-amd64-3.7\pycocotools
copying pycocotools\cocoeval.py -> build\lib.win-amd64-3.7\pycocotools
copying pycocotools\mask.py -> build\lib.win-amd64-3.7\pycocotools
copying pycocotools\__init__.py -> build\lib.win-amd64-3.7\pycocotools
running build_ext
building 'pycocotools._mask' extension
error: Microsoft Visual C++ 14.0 is required. Get it with "Build Tools for Visual Studio": https://visualstudio.microsoft.com/downloads/
----------------------------------------
ERROR: Command errored out with exit status 1: 'D:\Anaconda3\python.exe' -u -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'C:\\Users\\46653\\AppData\\Local\\Temp\\pip-install-j33342g5\\pycocotools\\setup.py'"'"'; __file__='"'"'C:\\Users\\46653\\AppData\\Local\\Temp\\pip-install-j33342g5\\pycocotools\\setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' install --record 'C:\Users\46653\AppData\Local\Temp\pip-record-ucmhdqzv\install-record.txt' --single-version-externally-managed --compile Check the logs for full command output.

3.解决办法

经过我大量的查找资料发现，这是因为你的Windows下没有c/c++代码编译环境，因为pycocotools的主站点源码https://github.com/cocodataset/cocoapi默认只提供了源码，没有针对各平台编译好了的Release，而且声称将来不支持Windows! 。

• 首先我们需要安装MS VC，下载地址：
  

  https://visualstudio.microsoft.com/zh-hans/downloads/

但是当你安装完，MS VC后发现仍会报错。

• 因为我们还需要下载安装visualcppbuildtools_full.exe，下载地址：
  

   https://go.microsoft.com/fwlink/?LinkId=691126

• 最后因为pip安装默认下载的源码是不支持Windows上编译的，需要从一个让pycocotools PythonAPI支持使用Windows和Python 3来build的clone站点https://github.com/philferriere/cocoapi来安装。
  打开cmd执行下面的命令：
  

pip install git+https://github.com/philferriere/cocoapi.git#subdirectory=PythonAPI

注意：由于github连接非常的不稳定，若中途报错远程连接断开并退出，可以多尝试几次。

• 也可以使用国内镜像源安装
  

pip install pycocotools-windows -i https://pypi.tuna.tsinghua.edu.cn/simple

上次安装成功

NanoDet成功的跑起来了