如果我想让 OpenCV dnn 模块加载 PyTorch 模型，我应该如何保存它

Question

我用 PyTorch 训练了一个简单的分类模型并用 opencv3.3 加载它，但它抛出异常并说

OpenCV Error: The function/feature is not implemented (Unsupported Lua type) in readObject, file /home/ramsus/Qt/3rdLibs/opencv/modules/dnn/src/torch/torch_importer.cpp, line 797 /home/ramsus/Qt/3rdLibs/opencv/modules/dnn/src/torch/torch_importer.cpp:797: error: (-213) Unsupported Lua type in function readObject

模型定义

class conv_block(nn.Module):
    def __init__(self, in_filter, out_filter, kernel):
        super(conv_block, self).__init__()

        self.conv1 = nn.Conv2d(in_filter, out_filter, kernel, 1, (kernel - 1)//2)
        self.batchnorm = nn.BatchNorm2d(out_filter)
        self.maxpool = nn.MaxPool2d(2, 2)

    def forward(self, x):
        x = self.conv1(x)
        x = self.batchnorm(x)
        x = F.relu(x)
        x = self.maxpool(x)

        return x

class Net(nn.Module):
    def __init__(self):
        super(Net, self).__init__()

        self.conv1 = conv_block(3, 6, 3)
        self.conv2 = conv_block(6, 16, 3)
        self.fc1 = nn.Linear(16 * 8 * 8, 120)
        self.bn1 = nn.BatchNorm1d(120)
        self.fc2 = nn.Linear(120, 84)
        self.bn2 = nn.BatchNorm1d(84)
        self.fc3 = nn.Linear(84, 10)

    def forward(self, x):
        x = self.conv1(x)
        x = self.conv2(x)
        x = x.view(x.size()[0], -1)
        x = F.relu(self.bn1(self.fc1(x)))
        x = F.relu(self.bn2(self.fc2(x)))
        x = self.fc3(x)
        return x

该模型仅使用Conv2d、ReLU、BatchNorm2d、MaxPool2d和Linear层，opencv3.3支持所有层

我用state_dict

保存

torch.save(net.state_dict(), 'cifar10_model')

用c++加载为

std::string const model_file("/home/some_folder/cifar10_model");

std::cout<<"read net from torch"<<std::endl;
dnn::Net net = dnn::readNetFromTorch(model_file);

我想我用错误的方式保存了模型，为了使用 OpenCV 加载，保存 PyTorch 模型的正确方法是什么？谢谢

编辑：

我用另一种方式保存了模型，也加载不出来

torch.save(net, 'cifar10_model.net')

这是一个错误吗？还是我做错了什么？

Answer 1

我找到了答案，opencv3.3 不支持 PyTorch (https://github.com/pytorch/pytorch) but pytorch (https://github.com/hughperkins/pytorch)，这是一个很大的惊喜，我从来不知道还有另一个版本的 pytorch 存在（看起来像一个死项目，很久了还没有更新），我希望他们能在 wiki 上提到他们支持的 pytorch。

如果我想让 OpenCV dnn 模块加载 PyTorch 模型，我应该如何保存它

How should I save the model of PyTorch if I want it loadable by OpenCV dnn module

c++

python

opencv

deep-learning

pytorch