使用AlexNet和从目录中读取的数据流来训练灰度数据集。

3
这是我的参考文献: 从目录示例流 AlexNet架构 我尝试使用AlexNet架构来训练3个类别的灰度图像数据集。我修改了第一个链接以成为分类模式,然后将CNN模型从第二个链接改为AlexNet。但是我收到了2个错误消息:
1. ValueError:由于从1中减去3而导致负维度大小,用于“conv2d_83 / convolution”(op:“ Conv2D”)的输入形状为[?,1,1,384],[3,3,384,384]。 2. 如果我更改img_width,img_height = 224,224 TypeError:Dense 只能接受1个位置参数('units'),但您传递了以下位置参数:[4096,(224,224,1)]
在CNN中是否存在不匹配的维度?谢谢。
这是代码:
import json
from keras.preprocessing.image import ImageDataGenerator
from keras.models import Sequential
from keras.layers import Conv2D, MaxPooling2D
from keras.layers import Activation, Dropout, Flatten, Dense
from keras import backend as K
#from tensorflow.keras.optimizers import RMSprop


# dimensions of our images.
img_width, img_height = 150,150

train_data_dir = 'data/train'
validation_data_dir = 'data/validation'
nb_train_samples = 200*3
nb_validation_samples = 50*3
epochs = 1
batch_size = 5

if K.image_data_format() == 'channels_first':
    input_shape = (1, img_width, img_height)
else:
    input_shape = (img_width, img_height, 1)
print(input_shape)
model = Sequential()
model.add(Conv2D(filters=96, input_shape=input_shape,data_format='channels_last', kernel_size=(11,11), strides=(4,4), padding='valid'))
model.add(Activation('relu'))
model.add(MaxPooling2D(pool_size=(2,2), strides=(2,2), padding='valid'))

model.add(Conv2D(filters=256, kernel_size=(11,11), strides=(1,1), padding='valid'))
model.add(Activation('relu'))
model.add(MaxPooling2D(pool_size=(2,2), strides=(2,2), padding='valid'))

model.add(Conv2D(filters=384, kernel_size=(3,3), strides=(1,1), padding='valid'))
model.add(Activation('relu'))
#model.add(MaxPooling2D(pool_size=(2, 2)))

# 4th Convolutional Layer
model.add(Conv2D(filters=384, kernel_size=(3,3), strides=(1,1), padding='valid'))
model.add(Activation('relu'))

# 5th Convolutional Layer
model.add(Conv2D(filters=256, kernel_size=(3,3), strides=(1,1), padding='valid'))
model.add(Activation('relu'))
model.add(MaxPooling2D(pool_size=(2,2), strides=(2,2), padding='valid'))

model.add(Flatten())
model.add(Dense(4096, input_shape))
model.add(Activation('relu'))
model.add(Dropout(0.4))

model.add(Dense(4096))
model.add(Activation('relu'))
model.add(Dropout(0.4))

model.add(Dense(1000))
model.add(Activation('relu'))
model.add(Dropout(0.4))

# Output Layer
model.add(Dense(3))
model.add(Activation('softmax'))

model.summary()

# Compile the model
model.compile(loss=keras.losses.categorical_crossentropy, optimizer='adam', metrics=['accuracy'])

#model.compile(loss='categorical_crossentropy',optimizer=RMSprop(lr=0.001),metrics=['accuracy'])

# this is the augmentation configuration we will use for training
train_datagen = ImageDataGenerator(
    rescale=1. / 255,
    shear_range=0.2,
    zoom_range=0.2,
    horizontal_flip=True)

# this is the augmentation configuration we will use for testing:
# only rescaling
test_datagen = ImageDataGenerator(rescale=1. / 255)

train_generator = train_datagen.flow_from_directory(
    train_data_dir,
    target_size=(img_width, img_height),
    color_mode='grayscale',
    batch_size=batch_size,
    class_mode='categorical')

validation_generator = test_datagen.flow_from_directory(
    validation_data_dir,
    target_size=(img_width, img_height),
    color_mode='grayscale',
    batch_size=batch_size,
    class_mode='categorical')

model.fit_generator(
    train_generator,
    steps_per_epoch=nb_train_samples // batch_size,
    epochs=epochs,
    validation_data=validation_generator,
    validation_steps=nb_validation_samples // batch_size)

model_json = model.to_json()
with open("model_in_json.json", "w") as json_file:
    json.dump(model_json, json_file)

model.save_weights("model_weights.h5")
1个回答

2
  1. AlexNet是为227x227的input_size设计的。论文中提到了224x224,但这是一个笔误。这并不是说你不能使用其他尺寸,但是架构将变得更加不合理。当输入尺寸太小时,即您的情况时,会出现更明显的问题。步幅为2的卷积和最大池化操作减小了后续层的维度。您会发现维度不足,这是由ValueError: Negative dimension size caused by subtracting 3 from 1 for 'conv2d_83/convolution'指示的。请升采样您的输入图像或更改架构。

  2. 错误源于model.add(Dense(4096, input_shape))。如果您查看keras文档中的Dense层,您会注意到第二个参数是activation。如果有的话,您应该使用model.add(Dense(4096, input_shape=your_input_shape))


哦,我的天啊,非常感谢您的编辑和回答这个问题。 - Harits Farabi

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