我将进入卷积神经网络,并希望为MNIST数据创建一个。每当我在CNN中添加一个卷积层时,我就会得到一个错误:
输入0与层conv2d_4不兼容:预期的ndim=4,找到ndim=5
我试图重塑X_Train数据集,但没有成功,我试图首先添加一个扁平层,但这会返回以下错误:
输入0与层conv2d_5不兼容:预期的ndim=4,找到ndim=2
import keras
from keras.preprocessing.image import ImageDataGenerator
from keras.models import Sequential
from keras.layers import Convolution2D
from keras.layers import Flatten, Dense, Dropout
img_width, img_height = 28, 28
mnist = keras.datasets.mnist
(X_train, Y_train), (X_test, Y_test) = mnist.load_data()
(X_train, y_train), (X_test, y_test) = mnist.load_data()
X_train = keras.utils.normalize(X_train, axis=1) #Normalizes from 0-1 (originally each pixel is valued 0-255)
X_test = keras.utils.normalize(X_test, axis=1) #Normalizes from 0-1 (originally each pixel is valued 0-255)
Y_train = keras.utils.to_categorical(Y_train) #Reshapes to allow ytrain to work with x train
Y_test = keras.utils.to_categorical(Y_test)
from sklearn import preprocessing
lb = preprocessing.LabelBinarizer()
Y_train = lb.fit_transform(Y_train)
Y_test = lb.fit_transform(Y_test)
#Model
model = Sequential()
model.add(Flatten())
model.add(Convolution2D(16, 5, 5, activation='relu', input_shape=(1,img_width, img_height, 1)))
model.add(Dense(128, activation='relu'))
model.add(Dense(128, activation='relu'))
model.add(Dropout(.2))
model.add(Dense(64, activation='relu'))
model.add(Dense(10, activation='softmax'))
model.compile(optimizer = 'adam',
loss='categorical_crossentropy',
metrics=['accuracy'])
model.fit(X_train, Y_train, epochs=3, verbose=2)
val_loss, val_acc = model.evaluate(X_test, Y_test) #Check to see if model fits test
print(val_loss, val_acc)如果我注释掉卷积层,它会很好地工作(accuracy>95%),但是我正在计划制造一个更复杂的神经网络,它将来需要卷积,这是我的出发点。
发布于 2019-07-01 22:14:32
代码中有两个问题。
to_categorical,另一次使用LabelBinarizer。这里不需要后者,所以只需使用to_categorical将标签编码为分类。2.-您的输入形状不正确,应该是(28, 28, 1)。
此外,您应该在卷积层之后添加一个Flatten层,这样Dense层才能正常工作。
发布于 2019-07-01 22:47:37
Keras正在寻找维数4的张量,但当维数为2时,它就会变小。首先,请确保Conv2D层中的内核大小在括号model.add(Convolution2D(32, (3, 3), activation='relu', input_shape=(img_height, img_height, 1)))中。
其次,您需要重塑X_train,X_test变量,因为Conv2D层需要一个张量输入。
X_train = X_train.reshape(-1,28, 28, 1) #Reshape for CNN - should work!! X_test = X_test.reshape(-1,28, 28, 1) model.fit(X_train, Y_train, epochs=3, verbose=2)
有关Conv2D的更多信息,您可以查看Keras文档这里
希望这能有所帮助。
https://stackoverflow.com/questions/56843008
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