加载YOLOv5时遭遇SSL证书验证失败问题求助

我需要在本地配合OpenCV使用YOLOv5模型（Colab无法访问本地摄像头），执行以下代码加载模型时出现SSL证书验证失败的错误：

model = torch.hub.load('ultralytics/yolov5', 'yolov5s', classes=30)
model.load_state_dict(torch.load('/PycharmProjects/ObjectDetection/best.pt')['model'].state_dict())

model = model.fuse().autoshape()

报错信息 #

runfile('/Users/lebedev/PycharmProjects/ObjectDetection/loadingmodel.py', wdir='/Users/lebedev/PycharmProjects/ObjectDetection')
Traceback (most recent call last):
  File "/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/urllib/request.py", line 1346, in do_open
...skipped...

ssl.SSLCertVerificationError: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: unable to get local issuer certificate (_ssl.c:1129)
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
  File "/Users/lebedev/PycharmProjects/ObjectDetection/venv/lib/python3.9/site-packages/IPython/core/interactiveshell.py", line 3378, in run_code
    exec(code_obj, self.user_global_ns, self.user_ns)
  File "<ipython-input-2-21519fa4e2b1>", line 1, in <module>
    runfile('/Users/lebedev/PycharmProjects/ObjectDetection/loadingmodel.py', wdir='/Users/lebedev/PycharmProjects/ObjectDetection')
  File "/Applications/PyCharm.app/Contents/plugins/python/helpers/pydev/_pydev_bundle/pydev_umd.py", line 198, in runfile
    pydev_imports.execfile(filename, global_vars, local_vars)  # execute the script
  File "/Applications/PyCharm.app/Contents/plugins/python/helpers/pydev/_pydev_imps/_pydev_execfile.py", line 18, in execfile
    exec(compile(contents+"\n", file, 'exec'), glob, loc)
  File "/Users/lebedev/PycharmProjects/ObjectDetection/loadingmodel.py", line 6, in <module>
    model = torch.hub.load('ultralytics/yolov5', 'yolov5s', classes=30)
  File "/Users/lebedev/PycharmProjects/ObjectDetection/venv/lib/python3.9/site-packages/torch/hub.py", line 537, in load
    repo_or_dir = _get_cache_or_reload(repo_or_dir, force_reload, trust_repo, "load",
  File "/Users/lebedev/PycharmProjects/ObjectDetection/venv/lib/python3.9/site-packages/torch/hub.py", line 180, in _get_cache_or_reload
    repo_owner, repo_name, ref = _parse_repo_info(github)
  File "/Users/lebedev/PycharmProjects/ObjectDetection/venv/lib/python3.9/site-packages/torch/hub.py", line 133, in _parse_repo_info
    with urlopen(f"https://github.com/{repo_owner}/{repo_name}/tree/main/"):
  File "/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/urllib/request.py", line 214, in urlopen
    return opener.open(url, data, timeout)
  File "/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/urllib/request.py", line 517, in open
    response = self._open(req, data)
  File "/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/urllib/request.py", line 534, in _open
    result = self._call_chain(self.handle_open, protocol, protocol +
  File "/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/urllib/request.py", line 494, in _call_chain
    result = func(*args)
  File "/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/urllib/request.py", line 1389, in https_open
    return self.do_open(http.client.HTTPSConnection, req,
  File "/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/urllib/request.py", line 1349, in do_open
    raise URLError(err)
urllib.error.URLError: <urlopen error [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: unable to get local issuer certificate (_ssl.c:1129)>

解决方案 #

方法1：本地克隆仓库加载（推荐） #

直接把YOLOv5仓库下载到本地，避免联网请求触发SSL验证：

1. 克隆仓库到项目目录：

git clone https://github.com/ultralytics/yolov5.git

2. 修改加载代码，从本地路径加载自定义权重：

# 从本地YOLOv5仓库加载自定义模型
model = torch.hub.load('./yolov5', 'custom', path='/PycharmProjects/ObjectDetection/best.pt', source='local')
model = model.fuse().autoshape()

说明：source='local'指定本地加载，无需联网；custom参数直接加载你的训练权重best.pt，无需额外调用load_state_dict。

方法2：临时跳过SSL验证（仅测试用） #

如果只是临时调试，可在代码开头添加以下代码绕过SSL验证：

import ssl
ssl._create_default_https_context = ssl._create_unverified_context

此方法会降低安全性，不建议在生产环境使用。

方法3：修复Mac系统Python证书 #

从报错路径看是Mac自带Python的证书缺失，执行以下步骤修复：

1. 打开终端运行：

open /Applications/Python\ 3.9/Install\ Certificates.command

2. 等待证书安装完成后，重启Python环境再尝试加载模型。

内容的提问来源于stack exchange，提问作者LEbEdEV