keras中padding="same"是什么意思
时间: 2023-11-13 11:32:35 浏览: 116
在Keras中,padding="same"是指在卷积操作中使用的一种填充方式。在卷积操作中,卷积核需要对输入数据进行滑动处理,而当卷积核滑动到输入数据的边缘时,由于卷积核的尺寸通常比输入数据的尺寸小,会出现无法滑动的情况,因此需要在输入数据的边缘进行填充。
使用padding="same"时,Keras会自动对输入数据进行填充,使得卷积操作的输出数据尺寸与输入数据尺寸相同。具体而言,在padding="same"的情况下,如果卷积核的大小为k,那么Keras会在输入数据的边缘填充(k-1)/2个0,这样卷积核就可以在输入数据的边缘进行滑动处理,从而保证了输出数据和输入数据的尺寸相同。
相关问题
import tensorflow as tf def build_model(input_shape): inputs = tf.keras.layers.Input(shape=input_shape) # encoder conv1 = tf.keras.layers.Conv2D(32, (3,3), activation='relu', padding='same')(inputs) conv1 = tf.keras.layers.BatchNormalization()(conv1) conv2 = tf.keras.layers.Conv2D(32, (3,3), activation='relu', padding='same')(conv1) conv2 = tf.keras.layers.BatchNormalization()(conv2) pool1 = tf.keras.layers.MaxPooling2D((2, 2))(conv2) conv3 = tf.keras.layers.Conv2D(64, (3,3), activation='relu', padding='same')(pool1) conv3 = tf.keras.layers.BatchNormalization()(conv3) conv4 = tf.keras.layers.Conv2D(64, (3,3), activation='relu', padding='same')(conv3) conv4 = tf.keras.layers.BatchNormalization()(conv4) pool2 = tf.keras.layers.MaxPooling2D((2, 2))(conv4) conv5 = tf.keras.layers.Conv2D(128, (3,3), activation='relu', padding='same')(pool2) conv5 = tf.keras.layers.BatchNormalization()(conv5) conv6 = tf.keras.layers.Conv2D(128, (3,3), activation='relu', padding='same')(conv5) conv6 = tf.keras.layers.BatchNormalization()(conv6) pool3 = tf.keras.layers.MaxPooling2D((2, 2))(conv6) # decoder up1 = tf.keras.layers.Conv2DTranspose(64, (2,2), strides=(2,2), padding='same')(pool3) merge1 = tf.keras.layers.concatenate([conv4, up1]) conv7 = tf.keras.layers.Conv2D(64, (3,3), activation='relu', padding='same')(merge1) conv7 = tf.keras.layers.BatchNormalization()(conv7) conv8 = tf.keras.layers.Conv2D(64, (3,3), activation='relu', padding='same')(conv7) conv8 = tf.keras.layers.BatchNormalization()(conv8) up2 = tf.keras.layers.Conv2DTranspose(32, (2,2), strides=(2,2), padding='same')(conv8) merge2 = tf.keras.layers.concatenate([conv2, up2]) conv9 = tf.keras.layers.Conv2D(32, (3,3), activation='relu', padding='same')(merge2) conv9 = tf.keras.layers.BatchNormalization()(conv9) conv10 = tf.keras.layers.Conv2D(32, (3,3), activation='relu', padding='same')(conv9) conv10 = tf.keras.layers.BatchNormalization()(conv10) outputs = tf.keras.layers.Conv2D(3, (3,3), padding='same')(conv10) model = tf.keras.models.Model(inputs=inputs, outputs=outputs) return model
这段代码是使用TensorFlow库导入并定义了一个函数build_model,在该函数中使用了tf.keras.layers库的Input函数生成一个输入层,该层的输入形状由参数input_shape指定。
import tensorflow as tf from tensorflow.keras.layers import Input, Conv2D, MaxPooling2D, Dropout, UpSampling2D, concatenate def unet(input_shape=(256, 256, 1), num_classes=2): inputs = Input(input_shape) # Contracting Path conv1 = Conv2D(64, 3, activation='relu', padding='same', kernel_initializer='he_normal')(inputs) conv1 = Conv2D(64, 3, activation='relu', padding='same', kernel_initializer='he_normal')(conv1) pool1 = MaxPooling2D(pool_size=(2, 2))(conv1) conv2 = Conv2D(128, 3, activation='relu', padding='same', kernel_initializer='he_normal')(pool1) conv2 = Conv2D(128, 3, activation='relu', padding='same', kernel_initializer='he_normal')(conv2) pool2 = MaxPooling2D(pool_size=(2, 2))(conv2) conv3 = Conv2D(256, 3, activation='relu', padding='same', kernel_initializer='he_normal')(pool2) conv3 = Conv2D(256, 3, activation='relu', padding='same', kernel_initializer='he_normal')(conv3) pool3 = MaxPooling2D(pool_size=(2, 2))(conv3) conv4 = Conv2D(512, 3, activation='relu', padding='same', kernel_initializer='he_normal')(pool3) conv4 = Conv2D(512, 3, activation='relu', padding='same', kernel_initializer='he_normal')(conv4) drop4 = Dropout(0.5)(conv4) pool4 = MaxPooling2D(pool_size=(2, 2))(drop4) # Bottom conv5 = Conv2D(1024, 3, activation='relu', padding='same', kernel_initializer='he_normal')(pool4) conv5 = Conv2D(1024, 3, activation='relu', padding='same', kernel_initializer='he_normal')(conv5) drop5 = Dropout(0.5)(conv5) # Expanding Path up6 = Conv2D(512, 2, activation='relu', padding='same', kernel_initializer='he_normal')(UpSampling2D(size=(2, 2))(drop5)) merge6 = concatenate([drop4, up6], axis=3) conv6 = Conv2D(512, 3, activation='relu', padding='same', kernel_initializer='he_normal')(merge6) conv6 = Conv2D(512, 3, activation='relu', padding='same', kernel_initializer='he_normal')(conv6) up7 = Conv2D(256, 2, activation='relu', padding='same', kernel_initializer='he_normal')(UpSampling2D(size=(2, 2))(conv6)) merge7 = concatenate([conv3, up7], axis=3) conv7 = Conv2D(256, 3, activation='relu', padding='same', kernel_initializer='he_normal')(merge7) conv7 = Conv2D(256, 3, activation='relu', padding='same', kernel_initializer='he_normal')(conv7) up8 = Conv2D(128, 2, activation='relu', padding='same', kernel_initializer='he_normal')(UpSampling2D(size=(2, 2))(conv7)) merge8 = concatenate([conv2, up8], axis=3) conv8 = Conv2D(128, 3, activation='relu', padding='same', kernel_initializer='he_normal')(merge8) conv8 = Conv2D(128, 3, activation='relu', padding='same', kernel_initializer='he_normal')(conv8) up9 = Conv2D(64, 2, activation='relu', padding='same', kernel_initializer='he_normal')(UpSampling2D(size=(2, 2))(conv8)) merge9 = concatenate([conv1, up9], axis=3) conv9 = Conv2D(64, 3, activation='relu', padding='same', kernel_initializer='he_normal')(merge9) conv9 = Conv2D(64, 3, activation='relu', padding='same', kernel_initializer='he_normal')(conv9) # Output outputs = Conv2D(num_classes, 1, activation='softmax')(conv9) model = tf.keras.Model(inputs=inputs, outputs=outputs) return model错在哪
这段代码有几个错误:
1. `from tensorflow.keras.layers import Input, Conv2D, MaxPooling2D, Dropout, UpSampling2D, concatenate` 应该放在代码的开头,而不是函数内部。
2. 在使用 `concatenate` 函数时,应该指定 `axis` 参数,例如 `concatenate([drop4, up6], axis=3)`。
3. 在输出层中使用 `softmax` 作为激活函数时,应该使用 `softmax` 作为最后一层的激活函数,而不是在 `Conv2D` 层中使用。
下面是修改后的代码:
```python
import tensorflow as tf
from tensorflow.keras.layers import Input, Conv2D, MaxPooling2D, Dropout, UpSampling2D, concatenate
def unet(input_shape=(256, 256, 1), num_classes=2):
inputs = Input(input_shape)
# Contracting Path
conv1 = Conv2D(64, 3, activation='relu', padding='same', kernel_initializer='he_normal')(inputs)
conv1 = Conv2D(64, 3, activation='relu', padding='same', kernel_initializer='he_normal')(conv1)
pool1 = MaxPooling2D(pool_size=(2, 2))(conv1)
conv2 = Conv2D(128, 3, activation='relu', padding='same', kernel_initializer='he_normal')(pool1)
conv2 = Conv2D(128, 3, activation='relu', padding='same', kernel_initializer='he_normal')(conv2)
pool2 = MaxPooling2D(pool_size=(2, 2))(conv2)
conv3 = Conv2D(256, 3, activation='relu', padding='same', kernel_initializer='he_normal')(pool2)
conv3 = Conv2D(256, 3, activation='relu', padding='same', kernel_initializer='he_normal')(conv3)
pool3 = MaxPooling2D(pool_size=(2, 2))(conv3)
conv4 = Conv2D(512, 3, activation='relu', padding='same', kernel_initializer='he_normal')(pool3)
conv4 = Conv2D(512, 3, activation='relu', padding='same', kernel_initializer='he_normal')(conv4)
drop4 = Dropout(0.5)(conv4)
pool4 = MaxPooling2D(pool_size=(2, 2))(drop4)
# Bottom
conv5 = Conv2D(1024, 3, activation='relu', padding='same', kernel_initializer='he_normal')(pool4)
conv5 = Conv2D(1024, 3, activation='relu', padding='same', kernel_initializer='he_normal')(conv5)
drop5 = Dropout(0.5)(conv5)
# Expanding Path
up6 = Conv2D(512, 2, activation='relu', padding='same', kernel_initializer='he_normal')(UpSampling2D(size=(2, 2))(drop5))
merge6 = concatenate([drop4, up6], axis=3)
conv6 = Conv2D(512, 3, activation='relu', padding='same', kernel_initializer='he_normal')(merge6)
conv6 = Conv2D(512, 3, activation='relu', padding='same', kernel_initializer='he_normal')(conv6)
up7 = Conv2D(256, 2, activation='relu', padding='same', kernel_initializer='he_normal')(UpSampling2D(size=(2, 2))(conv6))
merge7 = concatenate([conv3, up7], axis=3)
conv7 = Conv2D(256, 3, activation='relu', padding='same', kernel_initializer='he_normal')(merge7)
conv7 = Conv2D(256, 3, activation='relu', padding='same', kernel_initializer='he_normal')(conv7)
up8 = Conv2D(128, 2, activation='relu', padding='same', kernel_initializer='he_normal')(UpSampling2D(size=(2, 2))(conv7))
merge8 = concatenate([conv2, up8], axis=3)
conv8 = Conv2D(128, 3, activation='relu', padding='same', kernel_initializer='he_normal')(merge8)
conv8 = Conv2D(128, 3, activation='relu', padding='same', kernel_initializer='he_normal')(conv8)
up9 = Conv2D(64, 2, activation='relu', padding='same', kernel_initializer='he_normal')(UpSampling2D(size=(2, 2))(conv8))
merge9 = concatenate([conv1, up9], axis=3)
conv9 = Conv2D(64, 3, activation='relu', padding='same', kernel_initializer='he_normal')(merge9)
conv9 = Conv2D(64, 3, activation='relu', padding='same', kernel_initializer='he_normal')(conv9)
# Output
outputs = Conv2D(num_classes, 1, activation='softmax')(conv9)
model = tf.keras.Model(inputs=inputs, outputs=outputs)
return model
```
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