Keras CNN 维度问题

Question

基于this 文章，我正在尝试使用 Keras 构建一个 CNN 用于图像分割任务。因为我的数据集很小，所以我想使用 Keras ImageDataGenerator 并将其提供给 fit_generator()。所以，我在 Keras 网站上关注了example。但是，由于压缩图像和蒙版生成器不起作用，我按照这个answer 创建了自己的生成器。

我的输入数据大小为(701,256,1)，我的问题是二进制（前景、背景）。对于每张图片，我都有一个相同形状的标签。

现在，我面临一个维度问题。 answer中也提到了这一点，但我不确定如何解决。

错误：

 ValueError: Error when checking target: expected dense_3 to have 2 dimensions, but got array with shape (2, 704, 256, 1)

我正在粘贴我在这里的整个代码：

import numpy
import pygpu
import theano
import keras

from keras.models import Model, Sequential
from keras.layers import Input, Dense, Dropout, Activation, Flatten
from keras.layers import Conv2D, MaxPooling2D, Reshape
from keras.layers import BatchNormalization
from keras.preprocessing.image import ImageDataGenerator

from keras.utils import np_utils
from keras import backend as K

def superGenerator(image_gen, label_gen):
    while True:
      x = image_gen.next()
      y = label_gen.next()
      yield x[0], y[0]


img_height = 704
img_width = 256

train_data_dir = 'Dataset/Train/Images'
train_label_dir = 'Dataset/Train/Labels'
validation_data_dir = 'Dataset/Validation/Images'
validation_label_dir = 'Dataset/Validation/Labels'
n_train_samples = 1000
n_validation_samples = 500
epochs = 50
batch_size = 2

input_shape = (img_height, img_width,1)
target_shape = (img_height, img_width)

model = Sequential()

model.add(Conv2D(80,(28,28), input_shape=input_shape))
model.add(BatchNormalization())
model.add(Activation('relu'))
model.add(MaxPooling2D(pool_size=(2,2), strides=(2,2)))

model.add(Conv2D(96,(18,18)))
model.add(BatchNormalization())
model.add(Activation('relu'))
model.add(MaxPooling2D(pool_size=(2,2), strides=(2,2)))

model.add(Conv2D(128,(13,13)))
model.add(BatchNormalization())
model.add(Activation('relu'))
model.add(MaxPooling2D(pool_size=(2,2),strides=(2,2)))


model.add(Conv2D(160,(8,8)))
model.add(BatchNormalization())
model.add(Activation('relu'))
model.add(MaxPooling2D(pool_size=(2,2)))

model.add(Flatten())

model.add(Dense(1024, activation='relu'))
model.add(Dense(512, activation='relu'))
model.add(Dropout(0.25))

model.add(Dense(2, activation='softmax'))

model.summary()

model.compile(loss='binary_crossentropy', optimizer='nadam', metrics=['accuracy'])

data_gen_args = dict(
    rescale=1./255,
    horizontal_flip=True,
    vertical_flip=True
    )

train_datagen = ImageDataGenerator(**data_gen_args)
train_label_datagen = ImageDataGenerator(**data_gen_args)
test_datagen = ImageDataGenerator(**data_gen_args)
test_label_datagen = ImageDataGenerator(**data_gen_args)

seed = 1

train_image_generator = train_datagen.flow_from_directory(
    train_data_dir,
    target_size=target_shape,
    color_mode='grayscale',
    batch_size=batch_size,
    class_mode = 'binary',
    seed=seed)
train_label_generator = train_label_datagen.flow_from_directory(
    train_label_dir,
    target_size=target_shape,
    color_mode='grayscale',
    batch_size=batch_size,
    class_mode = 'binary',
    seed=seed)

validation_image_generator = test_datagen.flow_from_directory(
    validation_data_dir,
    target_size=target_shape,
    color_mode='grayscale',
    batch_size=batch_size,
    class_mode = 'binary',
    seed=seed)

validation_label_generator = test_label_datagen.flow_from_directory(
    validation_label_dir,
    target_size=target_shape,
    color_mode='grayscale',
    batch_size=batch_size,
    class_mode = 'binary',
    seed=seed)

train_generator = superGenerator(train_image_generator, train_label_generator,batch_size)
test_generator = superGenerator(validation_image_generator, validation_label_generator,batch_size)

model.fit_generator(
    train_generator,
    steps_per_epoch= n_train_samples // batch_size,
    epochs=50,
    validation_data=test_generator,
    validation_steps=n_validation_samples // batch_size)

model.save_weights('first_try.h5')

我是 Keras（和 CNN）的新手，因此非常感谢任何帮助。

Answer 1

好的。我做了一些橡皮鸭调试并阅读了更多文章。当然，维度是个问题。 This 简单的答案为我做了。 我的标签与输入图像的形状相同，因此模型的输出也应具有该形状。我使用Conv2DTranspose 解决了这个问题。