Unet Keras ValueError: Dimensions must be equal

Question

我使用了 512x512x1 输入形状的 unet 模型但我有一个问题。我收到一个 ValueError：维度必须相等。我知道输入形状出了问题。我需要解决这个问题problem.maybe 模型丢失有问题

X 火车形状：(512, 512, 1) Y 火车形状：(512, 512, 1)

型号：

from keras.models import Model
from keras.layers import Dense, Dropout, Activation, Flatten
from keras.layers import concatenate, Conv2D, MaxPooling2D, Conv2DTranspose
from keras.layers import Input, merge, UpSampling2D,BatchNormalization
from keras.callbacks import ModelCheckpoint
from keras.optimizers import Adam
from keras.preprocessing.image import ImageDataGenerator
from keras import backend as K
import tensorflow as tf

K.set_image_data_format('channels_last')


def dice_coef(y_true, y_pred):
    smooth = 0.005 
    y_true_f = K.flatten(y_true)
    y_pred_f = K.flatten(y_pred)
    intersection = K.sum(y_true_f * y_pred_f)
    return (2. * intersection + smooth) / (K.sum(y_true_f) + K.sum(y_pred_f) + smooth)


def dice_coef_loss(y_true, y_pred):
    return 1-dice_coef(y_true, y_pred)
    
def unet_model():
    
    inputs = Input((512 , 512, 1))
    
    conv1 = Conv2D(64, (3, 3), activation='relu', padding='same') (inputs)
    batch1 = BatchNormalization(axis=1)(conv1)
    conv1 = Conv2D(64, (3, 3), activation='relu', padding='same') (batch1)
    batch1 = BatchNormalization(axis=1)(conv1)
    pool1 = MaxPooling2D((2, 2)) (batch1)
    
    conv2 = Conv2D(128, (3, 3), activation='relu', padding='same') (pool1)
    batch2 = BatchNormalization(axis=1)(conv2)
    conv2 = Conv2D(128, (3, 3), activation='relu', padding='same') (batch2)
    batch2 = BatchNormalization(axis=1)(conv2)
    pool2 = MaxPooling2D((2, 2)) (batch2)
    
    conv3 = Conv2D(256, (3, 3), activation='relu', padding='same') (pool2)
    batch3 = BatchNormalization(axis=1)(conv3)
    conv3 = Conv2D(256, (3, 3), activation='relu', padding='same') (batch3)
    batch3 = BatchNormalization(axis=1)(conv3)
    pool3 = MaxPooling2D((2, 2)) (batch3)
    
    conv4 = Conv2D(512, (3, 3), activation='relu', padding='same') (pool3)
    batch4 = BatchNormalization(axis=1)(conv4)
    conv4 = Conv2D(512, (3, 3), activation='relu', padding='same') (batch4)
    batch4 = BatchNormalization(axis=1)(conv4)
    pool4 = MaxPooling2D(pool_size=(2, 2)) (batch4)
    
    conv5 = Conv2D(1024, (3, 3), activation='relu', padding='same') (pool4)
    batch5 = BatchNormalization(axis=1)(conv5)
    conv5 = Conv2D(1024, (3, 3), activation='relu', padding='same') (batch5)
    batch5 = BatchNormalization(axis=1)(conv5)
    
    up6 = Conv2DTranspose(512, (2, 2), strides=(2, 2), padding='same') (batch5)
    up6 = concatenate([up6, conv4], axis=1)
    conv6 = Conv2D(512, (3, 3), activation='relu', padding='same') (up6)
    batch6 = BatchNormalization(axis=1)(conv6)
    conv6 = Conv2D(512, (3, 3), activation='relu', padding='same') (batch6)
    batch6 = BatchNormalization(axis=1)(conv6)
    
    up7 = Conv2DTranspose(256, (2, 2), strides=(2, 2), padding='same') (batch6)
    up7 = concatenate([up7, conv3], axis=1)
    conv7 = Conv2D(256, (3, 3), activation='relu', padding='same') (up7)
    batch7 = BatchNormalization(axis=1)(conv7)
    conv7 = Conv2D(256, (3, 3), activation='relu', padding='same') (batch7)
    batch7 = BatchNormalization(axis=1)(conv7)
    
    up8 = Conv2DTranspose(128, (2, 2), strides=(2, 2), padding='same') (batch7)
    up8 = concatenate([up8, conv2], axis=1)
    conv8 = Conv2D(128, (3, 3), activation='relu', padding='same') (up8)
    batch8 = BatchNormalization(axis=1)(conv8)
    conv8 = Conv2D(128, (3, 3), activation='relu', padding='same') (batch8)
    batch8 = BatchNormalization(axis=1)(conv8)
    
    up9 = Conv2DTranspose(64, (2, 2), strides=(2, 2), padding='same') (batch8)
    up9 = concatenate([up9, conv1], axis=1)
    conv9 = Conv2D(64, (3, 3), activation='relu', padding='same') (up9)
    batch9 = BatchNormalization(axis=1)(conv9)
    conv9 = Conv2D(64, (3, 3), activation='relu', padding='same') (batch9)
    batch9 = BatchNormalization(axis=1)(conv9)

    conv10 = Conv2D(1, (1, 1), activation='sigmoid')(batch9)

    model = Model(inputs=[inputs], outputs=[conv10])

    model.compile(optimizer=Adam(lr=1e-4), loss=dice_coef_loss, metrics=[dice_coef])

    return model

model = unet_model()

Answer 1

如果您查看模型摘要 (model.summary())，您将看到最后一层输出形状为：

Layer (type)              Output Shape      Param #      Connected to                
===============================================================================
...
...
conv2d_18 (Conv2D)    (None, 2560, 512, 1)    65      batch_normalization_17[0][0]

输出形状为 (None,2560,512,1)，与所需的输出形状 (None, 512, 512, 1)

不匹配

这种不匹配是因为您的 concatenate 层。您已在连接第二个轴的 concatenate 图层中设置了 axis=1 参数，但您需要根据最后一个轴 axis=-1 和默认值连接图层。

因此，从连接层中删除轴参数以使其保持默认值或在所有连接层中设置 axis=-1。

例如：

#up6 = concatenate([up6, conv4], axis=1) # remove axis
up6 = concatenate([up6, conv4])

然后，您将获得与您的输入和 y_train:

相同的最后一层形状

Layer (type)              Output Shape      Param #      Connected to                
===============================================================================
...
...
conv2d_18 (Conv2D)    (None, 512, 512, 1)    65      batch_normalization_17[0][0]

Unet Keras ValueError: Dimensions must be equal

Unet Keras ValueError: Dimensions must be equal

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