Keras ValueError:预期输入的形状为(2,),但数组的形状为(16,)

时间:2019-04-23 07:51:17

标签: python tensorflow keras

我编写了以下代码,并试图从变型自动编码器模型预测图像:

编码器:

input_img = Input(shape=(28, 28, 3))

x = Conv2D(32, 3,
                  padding='same', 
                  activation='relu')(input_img)
x = Conv2D(64, 3,
                  padding='same', 
                  activation='relu',
                  strides=(2, 2))(x)
x = Conv2D(64, 3,
                  padding='same', 
                  activation='relu')(x)
x = Conv2D(64, 3,
                  padding='same', 
                  activation='relu')(x)

x = Flatten()(x)
x = Dense(16, activation='relu')(x)

# Two outputs, latent mean and (log)variance
z_mu = Dense(latent_dim)(x)
z_log_sigma = Dense(latent_dim)(x)

encoder = Model(inputs = input_img, outputs = x)

解码器:

# decoder takes the latent distribution sample as input
decoder_input = Input(K.int_shape(z)[1:])

# Expand to 784 total pixels
x = Dense(np.prod(shape_before_flattening[1:]),
                 activation='relu')(decoder_input)

# reshape
x = Reshape(shape_before_flattening[1:])(x)

# use Conv2DTranspose to reverse the conv layers 
x = Conv2DTranspose(32, 3,
                           padding='same', 
                           activation='relu',
                           strides=(2, 2))(x)
x = Conv2D(3, 3,
                  padding='same', 
                  activation='sigmoid')(x)

# decoder model statement
decoder = Model(decoder_input, x)

# apply the decoder to the sample from the latent distribution
z_decoded = decoder(z)

编码器如下:

_________________________________________________________________
Layer (type)                 Output Shape              Param #   
=================================================================
input_13 (InputLayer)        (None, 28, 28, 3)         0         
_________________________________________________________________
conv2d_1 (Conv2D)            (None, 28, 28, 32)        896       
_________________________________________________________________
conv2d_2 (Conv2D)            (None, 14, 14, 64)        18496     
_________________________________________________________________
conv2d_3 (Conv2D)            (None, 14, 14, 64)        36928     
_________________________________________________________________
conv2d_4 (Conv2D)            (None, 14, 14, 64)        36928     
_________________________________________________________________
flatten_1 (Flatten)          (None, 12544)             0         
_________________________________________________________________
dense_10 (Dense)             (None, 16)                200720    
=================================================================
Total params: 293,968
Trainable params: 293,968
Non-trainable params: 0

以及类似的解码器:

Layer (type)                 Output Shape              Param #   
=================================================================
input_15 (InputLayer)        (None, 2)                 0         
_________________________________________________________________
dense_14 (Dense)             (None, 12544)             37632     
_________________________________________________________________
reshape_3 (Reshape)          (None, 14, 14, 64)        0         
_________________________________________________________________
conv2d_transpose_2 (Conv2DTr (None, 28, 28, 32)        18464     
_________________________________________________________________
conv2d_6 (Conv2D)            (None, 28, 28, 3)         867       
=================================================================
Total params: 56,963
Trainable params: 56,963
Non-trainable params: 0
_________________________________________________________________

它运行得很好。这是完整的模型:

__________________________________________________________________________________________________
Layer (type)                    Output Shape         Param #     Connected to                     
==================================================================================================
input_13 (InputLayer)           (None, 28, 28, 3)    0                                            
__________________________________________________________________________________________________
conv2d_1 (Conv2D)               (None, 28, 28, 32)   896         input_13[0][0]                   
__________________________________________________________________________________________________
conv2d_2 (Conv2D)               (None, 14, 14, 64)   18496       conv2d_1[0][0]                   
__________________________________________________________________________________________________
conv2d_3 (Conv2D)               (None, 14, 14, 64)   36928       conv2d_2[0][0]                   
__________________________________________________________________________________________________
conv2d_4 (Conv2D)               (None, 14, 14, 64)   36928       conv2d_3[0][0]                   
__________________________________________________________________________________________________
flatten_1 (Flatten)             (None, 12544)        0           conv2d_4[0][0]                   
__________________________________________________________________________________________________
dense_10 (Dense)                (None, 16)           200720      flatten_1[0][0]                  
__________________________________________________________________________________________________
dense_11 (Dense)                (None, 2)            34          dense_10[0][0]                   
__________________________________________________________________________________________________
dense_12 (Dense)                (None, 2)            34          dense_10[0][0]                   
__________________________________________________________________________________________________
lambda_5 (Lambda)               (None, 2)            0           dense_11[0][0]                   
                                                                 dense_12[0][0]                   
__________________________________________________________________________________________________
model_16 (Model)                (None, 28, 28, 3)    56963       lambda_5[0][0]                   
__________________________________________________________________________________________________
custom_variational_layer_3 (Cus [(None, 28, 28, 3),  0           input_13[0][0]                   
                                                                 model_16[1][0]                   
==================================================================================================
Total params: 350,999
Trainable params: 350,999
Non-trainable params: 0
__________________________________________________________________________________________________

问题是当我尝试基于现有图像创建图像时。这显示了训练集中的图像:

rnd_file = np.random.choice(files)
file_id = os.path.basename(rnd_file)
img = imread(rnd_file)
plt.imshow(img)
plt.show()

然后,我将图像添加到编码器中以获得图像的潜在表示:

z = encoder.predict(img)

我有潜在的表示形式,我根据给定的表示形式将其解码为图像:

decoder.predict(z)

出现以下错误:

ValueError:检查输入时出错:预期input_15具有形状(2,)但具有形状(16,)的数组

z看起来像这样:

[0.         0.         0.         0.         0.         0.03668813
 0.10211123 0.08731555 0.         0.01327576 0.         0.
 0.         0.         0.03561973 0.02009114]

编码器的输出为(None,16),与我的z相同。它作为模型运行。我怎样才能解决这个问题?预先感谢

2 个答案:

答案 0 :(得分:0)

缺少一些代码来确切地了解您要实现的目标,但是至少存在两个问题:

  • 在此示例中,z的大小不是(None, 16),而是(16,)。您需要添加一个尺寸,例如:z = encoder.predict(img[np.newaxis, :])
  • 解码器的输入大小与编码器的输出大小不符

答案 1 :(得分:0)

错误消息告诉我,它期望一个长度为2的元组。

例如在此介绍性文章中:

https://blog.keras.io/a-ten-minute-introduction-to-sequence-to-sequence-learning-in-keras.html

他们这样做:

    output_tokens, h, c = decoder_model.predict(
        [target_seq] + states_value)

您的代码仅传递了target_seq,但没有传递states_value,在我看来,为什么会出现该错误。