MNIST digit recognition with ConvNet

All credits to: https://github.com/fchollet/keras/blob/master/examples/mnist_cnn.py . The following code is a modified version of the above. The error rate is about 0.9% after 10 epochs of training.


In [ ]:
import numpy as np
from keras.datasets import mnist
from keras.models import Sequential
from keras.layers import Dense, Dropout, Flatten
from keras.layers.convolutional import Conv2D, MaxPooling2D
from keras.utils import np_utils
from keras import backend as K
from keras.models import load_model

K.set_image_dim_ordering('th')

In [ ]:
#fix random seed for reproducibility
seed = 7
np.random.seed(seed)

In [ ]:
# load data
(X_train, y_train), (X_test, y_test) = mnist.load_data()
# reshape
X_train = X_train.reshape(X_train.shape[0], 1, 28, 28).astype('float32')
X_test = X_test.reshape(X_test.shape[0], 1, 28, 28).astype('float32')

In [ ]:
# normalize inputs from 0-255 to 0-1
X_train = X_train / 255
X_test = X_test / 255
# one hot encode outputs
y_train = np_utils.to_categorical(y_train)
y_test = np_utils.to_categorical(y_test)
num_classes = y_test.shape[1]

In [ ]:
def model():
	# create model
	model = Sequential()
	model.add(Conv2D(32, (5, 5), input_shape=(1, 28, 28), activation='relu'))
	model.add(MaxPooling2D(pool_size=(2, 2)))
	model.add(Dropout(0.2))
	model.add(Flatten())
	model.add(Dense(128, activation='relu'))
	model.add(Dense(num_classes, activation='softmax'))
	# Compile model
	model.compile(loss='categorical_crossentropy', optimizer='adam', metrics=['accuracy'])
	return model

Run the model


In [ ]:
# build the model
model = model()
# Fit the model
model.fit(X_train, y_train, validation_data=(X_test, y_test), epochs=10, batch_size=200, verbose=2)
# Final evaluation of the model
scores = model.evaluate(X_test, y_test, verbose=0)
print("Error: %.2f%%" % (100-scores[1]*100))