在 keras 中集成 resnet50 和 densenet121答案

【问题标题】：Ensemble resnet50 and densenet121 in keras在 keras 中集成 resnet50 和 densenet121
【发布时间】：2018-03-06 17:30:54
【问题描述】：

我想做一个 resnet50 和 desnsenet121 的合奏，但是出错了：

图形断开连接：无法在“input_8”层获取张量 Tensor("input_8:0", shape=(?, 224, 224, 3), dtype=float32) 的值。访问以下先前层没有问题：[]

以下是我的集成代码：

from keras import applications
from keras.layers import Dense, Dropout, Flatten, Conv2D, MaxPool2D
from keras.models import Model, Input
#from keras.engine.topology import Input
from keras.layers import Average

def resnet50():
    base_model = applications.resnet50.ResNet50(weights='imagenet', include_top=False, input_shape=(224, 224, 3))
    last = base_model.output
    x = Flatten()(last)
    x = Dense(2000, activation='relu')(x)
    preds = Dense(200, activation='softmax')(x)
    model = Model(base_model.input, preds)
    return model

def densenet121():
    base_model = applications.densenet.DenseNet121(weights='imagenet', include_top=False, input_shape=(224,224, 3))
    last = base_model.output
    x = Flatten()(last)
    x = Dense(2000, activation='relu')(x)
    preds = Dense(200, activation='softmax')(x)
    model = Model(base_model.input, preds)
    return model

resnet50_model = resnet50()
densenet121_model = densenet121()
ensembled_models = [resnet50_model,densenet121_model]
def ensemble(models,model_input):
    outputs = [model.outputs[0] for model in models]
    y = Average()(outputs)
    model = Model(model_input,y,name='ensemble')
    return model

model_input = Input(shape=(224,224,3))
ensemble_model = ensemble(ensembled_models,model_input)

我认为原因是当我将reset50和densenet121结合起来时，它们有自己的输入层，即使我使输入形状相同。不同的输入层会导致冲突。这只是我的猜测，我不确定如何解决它

【问题讨论】：

标签： machine-learning computer-vision deep-learning keras

【解决方案1】：

您可以在创建基础模型时设置input_tensor=model_input。

def resnet50(model_input):
    base_model = applications.resnet50.ResNet50(weights='imagenet', include_top=False, input_tensor=model_input)
    # ...

def densenet121(model_input):
    base_model = applications.densenet.DenseNet121(weights='imagenet', include_top=False, input_tensor=model_input)
    # ...

model_input = Input(shape=(224, 224, 3))
resnet50_model = resnet50(model_input)
densenet121_model = densenet121(model_input)

然后，基本模型将使用提供的 model_input 张量，而不是创建自己的单独输入张量。

【讨论】：