matlab在resnet结构中加入SE模块

在ResNet结构中加入SE模块，可以按照以下步骤进行：

1. 定义SE模块，该模块包含一个全局平均池化层、一个全连接层、一个ReLU激活函数、一个全连接层和一个Sigmoid激活函数。可以参考以下代码实现：

function layers = seBlock(numChannels, reductionRatio, layerNamePrefix)
    layers = [
        globalAveragePooling2dLayer('Name', [layerNamePrefix, 'se_global_pool'])
        fullyConnectedLayer(reductionRatio*numChannels, 'Name', [layerNamePrefix, 'se_fc1'])
        reluLayer('Name', [layerNamePrefix, 'se_relu'])
        fullyConnectedLayer(numChannels, 'Name', [layerNamePrefix, 'se_fc2'])
        sigmoidLayer('Name', [layerNamePrefix, 'se_sigmoid'])
    ];
end

2. 在ResNet的每个残差块之后添加SE模块。可以通过在ResNet的每个残差块的最后添加一个SE模块的方式来实现。可以参考以下代码实现：

function lgraph = addSEBlock(lgraph, numChannels, reductionRatio, layerNamePrefix, blockName)
    seLayers = seBlock(numChannels, reductionRatio, layerNamePrefix);
    lgraph = addLayers(lgraph, seLayers);
    lgraph = connectLayers(lgraph, [blockName, '/relu_out'], [layerNamePrefix, 'se_global_pool']);
    lgraph = connectLayers(lgraph, [layerNamePrefix, 'se_sigmoid'], [blockName, '/prod']);
end

3. 修改ResNet的每个残差块，以实现SE模块的连接。可以参考以下代码实现：

function lgraph = addSEToResNet(lgraph, numChannels, reductionRatio, layerNamePrefix, blockName)
    seBlockName = [blockName, '_SE'];
    lgraph = addSEBlock(lgraph, numChannels, reductionRatio, layerNamePrefix, seBlockName);
    lgraph = connectLayers(lgraph, [blockName, '/relu_out'], [seBlockName, '/prod_in']);
    lgraph = connectLayers(lgraph, [seBlockName, '/sigmoid'], [blockName, '/add']);
end

4. 使用MATLAB内置的ResNet-50网络作为基础模型，并在其中添加SE模块。可以参考以下代码实现：

net = resnet50;
inputLayerName = 'input';
outputLayerName = 'fc1000';
numChannels = 2048;
reductionRatio = 16;
layerNamePrefix = 'se_';
blockNames = {'res2a', 'res2b', 'res2c', 'res3a', 'res3b1', 'res3b2', 'res3b3', 'res4a', 'res4b1', 'res4b2', 'res4b3', 'res4b4', 'res4b5', 'res4b6', 'res4b7', 'res4b8', 'res4b9', 'res4b10', 'res4b11', 'res4b12', 'res4b13', 'res4b14', 'res4b15', 'res4b16', 'res5a', 'res5b', 'res5c'};
for i = 1:numel(blockNames)
    blockName = blockNames{i};
    net = addLayers(net, seBlock(numChannels, reductionRatio, [layerNamePrefix, blockName]));
    net = connectLayers(net, [blockName, '/relu_out'], [layerNamePrefix, blockName, '/prod_in']);
    net = connectLayers(net, [layerNamePrefix, blockName, '/sigmoid'], [blockName, '/add']);
end

需要注意的是，在添加SE模块时，需要确保SE模块的代码和ResNet代码之间的接口兼容，避免出现不兼容的情况导致程序无法正常运行。另外，如果SE模块中使用了C或者C++代码，需要使用MATLAB提供的MEX函数将C/C++代码转换为MATLAB可调用的函数。详细的使用方法可以参考MATLAB官方文档。