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vgg16bn.py
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vgg16bn.py
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from __future__ import division, print_function
import os, json
from glob import glob
import numpy as np
from scipy import misc, ndimage
from scipy.ndimage.interpolation import zoom
from keras.utils.data_utils import get_file
from keras import backend as K
from keras.layers.normalization import BatchNormalization
from keras.utils.data_utils import get_file
from keras.models import Sequential
from keras.layers.core import Flatten, Dense, Dropout, Lambda
from keras.layers.convolutional import Convolution2D, MaxPooling2D, ZeroPadding2D
from keras.layers.pooling import GlobalAveragePooling2D
from keras.optimizers import SGD, RMSprop, Adam
from keras.preprocessing import image
vgg_mean = np.array([123.68, 116.779, 103.939], dtype=np.float32).reshape((3,1,1))
def vgg_preprocess(x):
x = x - vgg_mean
return x[:, ::-1] # reverse axis rgb->bgr
class Vgg16BN():
"""The VGG 16 Imagenet model with Batch Normalization for the Dense Layers"""
def __init__(self, size=(224,224), include_top=True):
self.FILE_PATH = 'http://www.platform.ai/models/'
self.create(size, include_top)
self.get_classes()
def get_classes(self):
fname = 'imagenet_class_index.json'
fpath = get_file(fname, self.FILE_PATH+fname, cache_subdir='models')
with open(fpath) as f:
class_dict = json.load(f)
self.classes = [class_dict[str(i)][1] for i in range(len(class_dict))]
def predict(self, imgs, details=False):
all_preds = self.model.predict(imgs)
idxs = np.argmax(all_preds, axis=1)
preds = [all_preds[i, idxs[i]] for i in range(len(idxs))]
classes = [self.classes[idx] for idx in idxs]
return np.array(preds), idxs, classes
def ConvBlock(self, layers, filters):
model = self.model
for i in range(layers):
model.add(ZeroPadding2D((1, 1)))
model.add(Convolution2D(filters, 3, 3, activation='relu'))
model.add(MaxPooling2D((2, 2), strides=(2, 2)))
def FCBlock(self):
model = self.model
model.add(Dense(4096, activation='relu'))
model.add(BatchNormalization())
model.add(Dropout(0.5))
def create(self, size, include_top):
if size != (224,224):
include_top=False
model = self.model = Sequential()
model.add(Lambda(vgg_preprocess, input_shape=(3,)+size))
self.ConvBlock(2, 64)
self.ConvBlock(2, 128)
self.ConvBlock(3, 256)
self.ConvBlock(3, 512)
self.ConvBlock(3, 512)
if not include_top:
fname = 'vgg16_bn_conv.h5'
model.load_weights(get_file(fname, self.FILE_PATH+fname, cache_subdir='models'))
return
model.add(Flatten())
self.FCBlock()
self.FCBlock()
model.add(Dense(1000, activation='softmax'))
fname = 'vgg16_bn.h5'
model.load_weights(get_file(fname, self.FILE_PATH+fname, cache_subdir='models'))
def get_batches(self, path, gen=image.ImageDataGenerator(), shuffle=True, batch_size=8, class_mode='categorical'):
return gen.flow_from_directory(path, target_size=(224,224),
class_mode=class_mode, shuffle=shuffle, batch_size=batch_size)
def ft(self, num):
model = self.model
model.pop()
for layer in model.layers: layer.trainable=False
model.add(Dense(num, activation='softmax'))
self.compile()
def finetune(self, batches):
model = self.model
model.pop()
for layer in model.layers: layer.trainable=False
model.add(Dense(batches.nb_class, activation='softmax'))
self.compile()
def compile(self, lr=0.001):
self.model.compile(optimizer=Adam(lr=lr),
loss='categorical_crossentropy', metrics=['accuracy'])
def fit_data(self, trn, labels, val, val_labels, nb_epoch=1, batch_size=64):
self.model.fit(trn, labels, nb_epoch=nb_epoch,
validation_data=(val, val_labels), batch_size=batch_size)
def fit(self, batches, val_batches, nb_epoch=1):
self.model.fit_generator(batches, samples_per_epoch=batches.nb_sample, nb_epoch=nb_epoch,
validation_data=val_batches, nb_val_samples=val_batches.nb_sample)
def test(self, path, batch_size=8):
test_batches = self.get_batches(path, shuffle=False, batch_size=batch_size, class_mode=None)
return test_batches, self.model.predict_generator(test_batches, test_batches.nb_sample)