具有多个输出并使用add_loss的自定义损失函数

时间:2019-03-13 20:37:03

标签: python tensorflow keras loss-function

我在keras中有一个自动编码器,我需要一个损失函数,该函数是mse,binary_crossentropy和第三部分的结合,第三部分试图使输出像素的数量最少(其值不同于0或1)。损失应该是这样的:a mse + b binary_crossentropy + c * L。我为此使用了以下代码,但会产生此错误:

  

回溯(最近通话最近):文件   “”,第134行,如果   (pred_w(i,j)> = 0&pred_w(i,j)<0.1)|(pred_w(i,j)<= 1&   pred_w(i,j)> = 0.9):TypeError:'Tensor'对象不可调用

能否请您告诉我该怎么做才能解决此问题?感谢您的帮助。

wtm=Input((4,4,1))
image = Input((28, 28, 1))
conv1 = Conv2D(64, (5, 5), activation='relu', padding='same', name='convl1e')(image)
conv2 = Conv2D(64, (5, 5), activation='relu', padding='same', name='convl2e')(conv1)
conv3 = Conv2D(64, (5, 5), activation='relu', padding='same', name='convl3e')(conv2)
#conv3 = Conv2D(8, (3, 3), activation='relu', padding='same', name='convl3e', kernel_initializer='Orthogonal',bias_initializer='glorot_uniform')(conv2)
BN=BatchNormalization()(conv3)
encoded =  Conv2D(1, (5, 5), activation='relu', padding='same',name='encoded_I')(BN)

#-----------------------adding w---------------------------------------   

wpad=Kr.layers.Lambda(lambda xy: xy[0] + Kr.backend.spatial_2d_padding(xy[1], padding=((0, 24), (0, 24))))
encoded_merged=wpad([encoded,wtm])

#-----------------------decoder------------------------------------------------
#------------------------------------------------------------------------------
deconv1 = Conv2D(64, (5, 5), activation='elu', padding='same', name='convl1d')(encoded_merged)
deconv2 = Conv2D(64, (5, 5), activation='elu', padding='same', name='convl2d')(deconv1)
deconv3 = Conv2D(64, (5, 5), activation='elu',padding='same', name='convl3d')(deconv2)
deconv4 = Conv2D(64, (5, 5), activation='elu',padding='same', name='convl4d')(deconv3)
BNd=BatchNormalization()(deconv4)

decoded = Conv2D(1, (5, 5), activation='sigmoid', padding='same', name='decoder_output')(BNd)    
model=Model(inputs=[image,wtm],outputs=decoded)

decoded_noise = GaussianNoise(0.5)(decoded)

#----------------------w extraction------------------------------------
convw1 = Conv2D(64, (5,5), activation='relu', name='conl1w')(decoded_noise)#24
convw2 = Conv2D(64, (5,5), activation='relu', name='convl2w')(convw1)#20
convw3 = Conv2D(64, (5,5), activation='relu' ,name='conl3w')(convw2)#16
convw4 = Conv2D(64, (5,5), activation='relu' ,name='conl4w')(convw3)#12
convw5 = Conv2D(64, (5,5), activation='relu', name='conl5w')(convw4)#8
convw6 = Conv2D(64, (5,5), activation='relu', name='conl6w')(convw5)#4
convw7 = Conv2D(64, (5,5), activation='relu',padding='same', name='conl7w',dilation_rate=(2,2))(convw6)#4
convw8 = Conv2D(64, (5,5), activation='relu', padding='same',name='conl8w',dilation_rate=(2,2))(convw7)#4
convw9 = Conv2D(64, (5,5), activation='relu',padding='same', name='conl9w',dilation_rate=(2,2))(convw8)#4
convw10 = Conv2D(64, (5,5), activation='relu',padding='same', name='conl10w',dilation_rate=(2,2))(convw9)#4
BNed=BatchNormalization()(convw10)
pred_w = Conv2D(1, (1, 1), activation='sigmoid', padding='same', name='reconstructed_W',dilation_rate=(2,2))(BNed)  

w_extraction=Model(inputs=[image,wtm],outputs=[decoded,pred_w])

count=0
for i in range(28):
    for j in range(28):
        if (pred_w(i,j)>=0 & pred_w(i,j)<0.1)|(pred_w(i,j)<=1 & pred_w(i,j)>=0.9):
            count+=1

loss = K.sum(0.7*mse(decoded, image),binary_crossentropy(pred_w,wtm))+count
w_extraction.add_loss(loss)

1 个答案:

答案 0 :(得分:0)

从技术上讲,该错误只是告诉您,如果要引用矩阵的条目,则pred_w [i,j]应该是pred_w [i,j]。但是,要按预期运行该代码,则需要进行大量重写。

要真正优化损失,主要的问题是,网络的权重必须是可区分的。在这种情况下可以使用的示例可能是:

  • (x-0.5)^ N相对较高的N

  • 或对数屏障,即-log(x)-log(1-x)

使用

这样的方法实际上可以对数字进行计数(这对优化没有帮助)。
count = tf.sum(pred_w<=0.1) + tf.sum(predictions_w>=0.9)

也许这对于在训练或类似过程中输出该范围内的数字很有帮助。