MNIST

MNISTとは？
Mixed National Institute of Standards and Technology database
手書き60000枚とテスト画像10000枚の画像データセット

MNISTのデータDL
http://yann.lecun.com/exdb/mnist/

import keras 
from keras.datasets import mnist
from keras.models import Sequential
from keras.layers import Dense, Dropout, InputLayer
from keras.optimizers import RMSprop

(x_train, y_train),(x_test,y_test) = mnist.load_data()

x_train = x_train.reshape(60000, 748)
x_test = x_test.reshape(10000, 784)
x_train = x_train.astype('float32')
x_test = x_test.astype('float32')
x_train /= 255
x_test /= 255
y_train = keras.utils.to_categorical(y_train, 10)
y_test = keras.utils.to_categorical(y_test, 10)

model = Sequential()
model.add(InputLayer(input_shape=(784,)))
model.add(Dense(10, activation='softmax'))
model.compile(loss='categorical_crossentropy',optimizer='rmsprop', metrics=['accuracy'])

epochs = 20
batch_size = 128
history = model.fit(x_train, y_train, batch_size=batch_size, epochs=epochs, verbose=1, validation_data=(x_test, y_test))

score = model.evaluate(x_test, y_test, verbose=1)
print()
print('Test loss:', score[0])
print('Test accuracy:', score[1])

MNISTのデータは縦28ピクセル x 横28ピクセル = 計748ピクセル
各ピクセルRGBは 0 – 255 の256種類の整数値