tfkeras_demo.py

from __future__ import print_function
import tensorflow as tf
import tensorflow.keras as keras
from tensorflow.keras.models import Sequential
from tensorflow.keras.layers import Dense, Dropout, Flatten
from tensorflow.keras.layers import Conv2D, MaxPooling2D
from keras.regularizers import l2
import os
import numpy as np
# Adapted from: https://keras.io/examples/mnist_cnn/

def load_acchu_data(mode='train'):
    path = os.path.split(__file__)[0]
    labels_path = os.path.join(path,'data',mode+'-label-onehot.npy')
    images_path = os.path.join(path,'data',mode+'-image.npy')
    labels = np.load(labels_path)
    images = np.load(images_path)
    # skip the rows which are more than 2 sides exceeding boundary.
    keep_rows = []
    for i in range(images.shape[0]):
        img = images[i,:].reshape(28,28)
        hasTopFilled=any(img[0,:])
        hasBotFilled=any(img[27,:])
        hasLeftFilled=any(img[:,0])
        hasRightFilled=any(img[:,27])
        if sum([hasBotFilled, hasTopFilled, hasLeftFilled, hasRightFilled]) < 2:
            keep_rows.append(i)
    return labels[keep_rows,:],images[keep_rows,:]

batch_size = 128
num_classes = 13
epochs = 150

# input image dimensions
img_rows, img_cols = 28, 28

# the data, split between train and test sets
y_train, x_train  = load_acchu_data('train')
nrows = len(y_train)
ntrain = int(nrows*0.75)
ntest = nrows - ntrain
print('test - train split: ',ntrain,ntest)
y_test = y_train[ntrain+1:,:]
x_test = x_train[ntrain+1:,:]

y_train = y_train[:ntrain,:]
x_train = x_train[:ntrain,:]

print("Train rows = {0}".format(y_train.shape[0]))
print("Test rows = {0}".format(y_test.shape[0]))

x_train = x_train.reshape(len(x_train), img_rows, img_cols,1)
x_test = x_test.reshape(len(x_test), img_rows, img_cols,1)
input_shape = (img_rows, img_cols,1)

x_train = x_train.astype('float32')
x_test = x_test.astype('float32')
x_train /= 255.0
x_test /= 255.0
print('x_train shape:', x_train.shape)
print(x_train.shape[0], 'train samples')
print(x_test.shape[0], 'test samples')

# convert class vectors to binary class matrices
#y_train = keras.utils.to_categorical(y_train, num_classes)
#y_test = keras.utils.to_categorical(y_test, num_classes)

#Conv model type-1 / larger (double convolution depth.)
model = Sequential()
model.add(Conv2D(64, kernel_size=(3, 3),
                 activation='relu',
                 input_shape=input_shape))
model.add(MaxPooling2D(pool_size=(2, 2)))
model.add(Conv2D(128, kernel_size=(3, 3),
                 activation='relu'))
model.add(MaxPooling2D(pool_size=(2, 2)))
model.add(Flatten(input_shape=(128,num_classes)))
model.add(Dense(num_classes, activation='softmax'))

model.compile(loss=keras.losses.categorical_crossentropy,
              optimizer=keras.optimizers.Adadelta(),
              metrics=['accuracy'])

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('Test loss:', score[0])
print('Test accuracy:', score[1])
model.save('acchu_conv3_model')