1. 错误描述

ModuleNotFoundError: No module named ‘cv2’

错误详情：

Traceback (most recent call last):
  File "train.py", line 12, in <module>
    from data_utils.build import make_dist_voc_loader
  File "/home/zhou/pytorch/yolo_1_pytorch/data_utils/build.py", line 1, in <module>
    from data_utils.datasets import *
  File "/home/zhou/pytorch/yolo_1_pytorch/data_utils/datasets/__init__.py", line 1, in <module>
    from data_utils.datasets.voc import VOCDatasets
  File "/home/zhou/pytorch/yolo_1_pytorch/data_utils/datasets/voc.py", line 3, in <module>
    import cv2
ModuleNotFoundError: No module named 'cv2'

2. 解决办法

安装opencv包,

pip install opencv-python

如果还不行，就安装完整版

pip install opencv-contrib-python

如果是3.6版本，则需要指定版本安装

pip install opencv-python==3.4.17.63

输出日志：

root@5e4fbbde504b:/home/zhou/pytorch/yolo_1_pytorch# pip install opencv-python==3.4.17.63
Looking in indexes: https://mirrors.aliyun.com/pypi/simple/
Collecting opencv-python==3.4.17.63
 Downloading https://mirrors.aliyun.com/pypi/packages/30/58/75e757f72e3d7506a4eda47b17195a92f23fb14d1ab23f738189bec01daf/opencv-python-3.4.17.63.tar.gz (87.8MB)
    |################################| 87.8MB 7.5MB/s 
 Installing build dependencies ... done
 Getting requirements to build wheel ... done
   Preparing wheel metadata ... done
Requirement already satisfied: numpy>=1.13.3; python_version < "3.7" in /opt/conda/lib/python3.6/site-packages (from opencv-python==3.4.17.63) (1.17.2)
Building wheels for collected packages: opencv-python
 Building wheel for opencv-python (PEP 517) ... done
 Created wheel for opencv-python: filename=opencv_python-3.4.17.63-cp36-cp36m-linux_x86_64.whl size=25780389 sha256=65587bc8d0df607cff9bdc9ec4c26e5af3bcc60a09a9f074a2f8004a17d82461
 Stored in directory: /root/.cache/pip/wheels/33/96/a6/42287c4d38f74541e9694c1243d7bf6a0ff5119fef03a2f613
Successfully built opencv-python
Installing collected packages: opencv-python
Successfully installed opencv-python-3.4.17.63

参考链接：opencv-python Project description