KERAS:预训练了CNN + Dense模型。如何冻结CNN权重并用LSTM替代Dense?

时间:2020-05-15 13:42:05

标签: keras lstm cnn pre-trained-model

我训练并加载了cnn +密集模型:

# load model
cnn_model = load_model('my_cnn_model.h5')
cnn_model.summary()

输出是这样(我的图像尺寸为2 X 3600):

_________________________________________________________________
Layer (type)                 Output Shape              Param #
=================================================================
conv2d_1 (Conv2D)            (None, 2, 3600, 32)       128
_________________________________________________________________
conv2d_2 (Conv2D)            (None, 2, 1800, 32)       3104
_________________________________________________________________
max_pooling2d_1 (MaxPooling2 (None, 2, 600, 32)        0
_________________________________________________________________
conv2d_3 (Conv2D)            (None, 2, 600, 64)        6208
_________________________________________________________________
conv2d_4 (Conv2D)            (None, 2, 300, 64)        12352
_________________________________________________________________
max_pooling2d_2 (MaxPooling2 (None, 2, 100, 64)        0
_________________________________________________________________
conv2d_5 (Conv2D)            (None, 2, 100, 128)       24704
_________________________________________________________________
conv2d_6 (Conv2D)            (None, 2, 50, 128)        49280
_________________________________________________________________
max_pooling2d_3 (MaxPooling2 (None, 2, 16, 128)        0
_________________________________________________________________
flatten_1 (Flatten)          (None, 4096)              0
_________________________________________________________________
dense_1 (Dense)              (None, 1024)              4195328
_________________________________________________________________
dense_2 (Dense)              (None, 1024)              1049600
_________________________________________________________________
dense_3 (Dense)              (None, 3)                 3075
=================================================================
Total params: 5,343,779
Trainable params: 5,343,779
Non-trainable params: 0

现在,我要保留的重量是扁平的,并用LSTM替换密集层以训练添加的LSTM零件。

我刚刚写道:

# freeze model
base_model = cnn_model(input_shape=(2, 3600, 1))

#base_model = cnn_model
base_model.trainable = False

# Adding the first lstm layer
x = LSTM(1024,activation='relu',return_sequences='True')(base_model.output)

# Adding the second lstm layer
x = LSTM(1024, activation='relu',return_sequences='False')(x)

# Adding the output
output = Dense(3,activation='linear')(x)

# Final model creation
model = Model(inputs=[base_model.input], outputs=[output])

但是我得到了:

base_model = cnn_model(input_shape=(2, 3600, 1))
TypeError: __call__() missing 1 required positional argument: 'inputs'

我知道我必须在Flatten层中理想地添加TimeDistributed,但是我不知道该怎么做。 此外,我不确定base_model.trainable = False是否确实符合我的要求。 你能帮我做这份工作吗?

非常感谢您!

1 个答案:

答案 0 :(得分:0)

您不能直接从Flatten()中获取输出,LSTM需要2维特征(时间,滤波器)。您必须重塑张量。

您可以在展平(最大池)之前从该层获取输出,假设该层在模型中具有索引i,我们可以从该层获取输出并根据需要对输出进行整形,将其传递给LSTM。

before_flatten = base_model.layers[i].output # i is the index of the layer from which you want to take the model output

conv2lstm_reshape = Reshape((-1, 2))(before_flatten) # you have to select it, the temporal dim and filters

# Adding the first lstm layer
x = LSTM(1024,activation='relu',return_sequences='True')(conv2lstm_reshape)

# Adding the second lstm layer
x = LSTM(1024, activation='relu',return_sequences='False')(x)

# Adding the output
output = Dense(3,activation='linear')(before_flatten)

# Final model creation
model = Model(inputs=[base_model.input], outputs=[output])

model.summary()