keras连接多个层会导致AttributeError:'NoneType'对象没有属性'_inbound_nodes' [英] keras Concatenate mulitple layers cause AttributeError: 'NoneType' object has no attribute '_inbound_nodes'

问题描述

我正在尝试在CNN中添加一些固定的内核，请参阅我的代码在下面.

I am trying to add some fixed kernels in my CNN, please see my codes below.

这是我创建内核的方式:

This is how I create my kernels:

# Kernels
def create_kernel(x):
    t = pipe(
        x, 
        lambda x: tf.constant(x, dtype=tf.float32), 
        lambda x: tf.reshape(x, [3, 3, 1, 1]))
    return t

k_edge1 = create_kernel([1, 0, -1, 0, 0, 0, -1, 0, 1])
k_edge2 = create_kernel([0, 1, 0, 1, -4, 1, 0, 1, 0])
k_edge3 = create_kernel([-1, -1, -1, -1, 8, -1, -1, -1, -1])

我的卷积网络就像:

# Convolution network
# Input layer
l_input = Input(shape=(28**2, ))
# Reshape layer
l_reshape = Reshape(target_shape=(28, 28, 1))(l_input)
# Convolution layers
l_conv1 = Conv2D(filters=20, kernel_size=(3, 3), padding='valid')(l_reshape)
l_edge1 = tf.nn.conv2d(l_reshape, k_edge1, strides=[1, 1, 1, 1], padding='VALID')
l_edge2 = tf.nn.conv2d(l_reshape, k_edge2, strides=[1, 1, 1, 1], padding='VALID')
l_edge3 = tf.nn.conv2d(l_reshape, k_edge3, strides=[1, 1, 1, 1], padding='VALID')
l_conv1a = Concatenate(axis=3)([l_conv1, l_edge1, l_edge2, l_edge3])  # <- The error should be caused by this line.
l_conv2 = Conv2D(filters=20, kernel_size=(3, 3), padding='valid')(l_conv1a)
l_pool1 = MaxPooling2D(pool_size=(2, 2), border_mode='valid')(l_conv2)
# Flatten layer
l_flat = Flatten()(l_pool1)
# Fully connected layers
l_fc1 = Dense(50, kernel_initializer='he_normal')(l_flat)
l_act1 = PReLU()(l_fc1)
l_fc3 = Dense(10, kernel_initializer='he_normal')(l_act1)
l_output = Activation('softmax')(l_fc1)

# Model
cnn_model = Model(l_input, l_output)

但是，出现以下错误:

Traceback (most recent call last):
File "<stdin>", line 2, in <module>
File "C:\Users\Perry Cheng\AppData\Local\conda\conda\envs\ml_py_3_6\lib\site-packages\keras\legacy\interfaces.py", line 91, in wrapper
    return func(*args, **kwargs)
File "C:\Users\Perry Cheng\AppData\Local\conda\conda\envs\ml_py_3_6\lib\site-packages\keras\engine\network.py", line 93, in __init__
    self._init_graph_network(*args, **kwargs)
File "C:\Users\Perry Cheng\AppData\Local\conda\conda\envs\ml_py_3_6\lib\site-packages\keras\engine\network.py", line 237, in _init_graph_network
    self.inputs, self.outputs)
File "C:\Users\Perry Cheng\AppData\Local\conda\conda\envs\ml_py_3_6\lib\site-packages\keras\engine\network.py", line 1353, in _map_graph_network
    tensor_index=tensor_index)
File "C:\Users\Perry Cheng\AppData\Local\conda\conda\envs\ml_py_3_6\lib\site-packages\keras\engine\network.py", line 1340, in build_map
    node_index, tensor_index)
File "C:\Users\Perry Cheng\AppData\Local\conda\conda\envs\ml_py_3_6\lib\site-packages\keras\engine\network.py", line 1340, in build_map
    node_index, tensor_index)
File "C:\Users\Perry Cheng\AppData\Local\conda\conda\envs\ml_py_3_6\lib\site-packages\keras\engine\network.py", line 1340, in build_map
    node_index, tensor_index)
[Previous line repeated 2 more times]
File "C:\Users\Perry Cheng\AppData\Local\conda\conda\envs\ml_py_3_6\lib\site-packages\keras\engine\network.py", line 1312, in build_map
    node = layer._inbound_nodes[node_index]
AttributeError: 'NoneType' object has no attribute '_inbound_nodes'

经过一些测试，我认为错误来自:

After some testing, I think the error comes from:

l_conv1a = Concatenate(axis=3)([l_conv1, l_edge1, l_edge2, l_edge3])

有什么办法解决吗?

推荐答案

Keras图层接受Keras张量而不是张量作为输入.因此，如果您想在Keras中使用tf.nn.conv2d而不是Conv2D层，则需要将它们包装在Lambda层中:

Keras layers accepts Keras Tensors and not Tensors as their input. So if you would like to use tf.nn.conv2d instead of Conv2D layers in Keras, you need to wrap them inside a Lambda layer:

l_edge1 = Lambda(lambda x: tf.nn.conv2d(x, k_edge1, strides=[1, 1, 1, 1], padding='VALID'))(l_reshape)
l_edge2 = Lambda(lambda x: tf.nn.conv2d(x, k_edge2, strides=[1, 1, 1, 1], padding='VALID'))(l_reshape)
l_edge3 = Lambda(lambda x: tf.nn.conv2d(x, k_edge3, strides=[1, 1, 1, 1], padding='VALID'))(l_reshape)

这篇关于keras连接多个层会导致AttributeError:'NoneType'对象没有属性'_inbound_nodes'的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！