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Example TensorFlow script for fine-tuning a VGG model (uses tf.contrib.data)
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""" | |
Example TensorFlow script for finetuning a VGG model on your own data. | |
Uses tf.contrib.data module which is in release v1.2 | |
Based on PyTorch example from Justin Johnson | |
(https://gist.github.com/jcjohnson/6e41e8512c17eae5da50aebef3378a4c) | |
Required packages: tensorflow (v1.2) | |
Download the weights trained on ImageNet for VGG: | |
``` | |
wget http://download.tensorflow.org/models/vgg_16_2016_08_28.tar.gz | |
tar -xvf vgg_16_2016_08_28.tar.gz | |
rm vgg_16_2016_08_28.tar.gz | |
``` | |
For this example we will use a tiny dataset of images from the COCO dataset. | |
We have chosen eight types of animals (bear, bird, cat, dog, giraffe, horse, | |
sheep, and zebra); for each of these categories we have selected 100 training | |
images and 25 validation images from the COCO dataset. You can download and | |
unpack the data (176 MB) by running: | |
``` | |
wget cs231n.stanford.edu/coco-animals.zip | |
unzip coco-animals.zip | |
rm coco-animals.zip | |
``` | |
The training data is stored on disk; each category has its own folder on disk | |
and the images for that category are stored as .jpg files in the category folder. | |
In other words, the directory structure looks something like this: | |
coco-animals/ | |
train/ | |
bear/ | |
COCO_train2014_000000005785.jpg | |
COCO_train2014_000000015870.jpg | |
[...] | |
bird/ | |
cat/ | |
dog/ | |
giraffe/ | |
horse/ | |
sheep/ | |
zebra/ | |
val/ | |
bear/ | |
bird/ | |
cat/ | |
dog/ | |
giraffe/ | |
horse/ | |
sheep/ | |
zebra/ | |
""" | |
import argparse | |
import os | |
import tensorflow as tf | |
import tensorflow.contrib.slim as slim | |
import tensorflow.contrib.slim.nets | |
parser = argparse.ArgumentParser() | |
parser.add_argument('--train_dir', default='coco-animals/train') | |
parser.add_argument('--val_dir', default='coco-animals/val') | |
parser.add_argument('--model_path', default='vgg_16.ckpt', type=str) | |
parser.add_argument('--batch_size', default=32, type=int) | |
parser.add_argument('--num_workers', default=4, type=int) | |
parser.add_argument('--num_epochs1', default=10, type=int) | |
parser.add_argument('--num_epochs2', default=10, type=int) | |
parser.add_argument('--learning_rate1', default=1e-3, type=float) | |
parser.add_argument('--learning_rate2', default=1e-5, type=float) | |
parser.add_argument('--dropout_keep_prob', default=0.5, type=float) | |
parser.add_argument('--weight_decay', default=5e-4, type=float) | |
VGG_MEAN = [123.68, 116.78, 103.94] | |
def list_images(directory): | |
""" | |
Get all the images and labels in directory/label/*.jpg | |
""" | |
labels = os.listdir(directory) | |
# Sort the labels so that training and validation get them in the same order | |
labels.sort() | |
files_and_labels = [] | |
for label in labels: | |
for f in os.listdir(os.path.join(directory, label)): | |
files_and_labels.append((os.path.join(directory, label, f), label)) | |
filenames, labels = zip(*files_and_labels) | |
filenames = list(filenames) | |
labels = list(labels) | |
unique_labels = list(set(labels)) | |
label_to_int = {} | |
for i, label in enumerate(unique_labels): | |
label_to_int[label] = i | |
labels = [label_to_int[l] for l in labels] | |
return filenames, labels | |
def check_accuracy(sess, correct_prediction, is_training, dataset_init_op): | |
""" | |
Check the accuracy of the model on either train or val (depending on dataset_init_op). | |
""" | |
# Initialize the correct dataset | |
sess.run(dataset_init_op) | |
num_correct, num_samples = 0, 0 | |
while True: | |
try: | |
correct_pred = sess.run(correct_prediction, {is_training: False}) | |
num_correct += correct_pred.sum() | |
num_samples += correct_pred.shape[0] | |
except tf.errors.OutOfRangeError: | |
break | |
# Return the fraction of datapoints that were correctly classified | |
acc = float(num_correct) / num_samples | |
return acc | |
def main(args): | |
# Get the list of filenames and corresponding list of labels for training et validation | |
train_filenames, train_labels = list_images(args.train_dir) | |
val_filenames, val_labels = list_images(args.val_dir) | |
assert set(train_labels) == set(val_labels),\ | |
"Train and val labels don't correspond:\n{}\n{}".format(set(train_labels), | |
set(val_labels)) | |
num_classes = len(set(train_labels)) | |
# -------------------------------------------------------------------------- | |
# In TensorFlow, you first want to define the computation graph with all the | |
# necessary operations: loss, training op, accuracy... | |
# Any tensor created in the `graph.as_default()` scope will be part of `graph` | |
graph = tf.Graph() | |
with graph.as_default(): | |
# Standard preprocessing for VGG on ImageNet taken from here: | |
# https://github.com/tensorflow/models/blob/master/research/slim/preprocessing/vgg_preprocessing.py | |
# Also see the VGG paper for more details: https://arxiv.org/pdf/1409.1556.pdf | |
# Preprocessing (for both training and validation): | |
# (1) Decode the image from jpg format | |
# (2) Resize the image so its smaller side is 256 pixels long | |
def _parse_function(filename, label): | |
image_string = tf.read_file(filename) | |
image_decoded = tf.image.decode_jpeg(image_string, channels=3) # (1) | |
image = tf.cast(image_decoded, tf.float32) | |
smallest_side = 256.0 | |
height, width = tf.shape(image)[0], tf.shape(image)[1] | |
height = tf.to_float(height) | |
width = tf.to_float(width) | |
scale = tf.cond(tf.greater(height, width), | |
lambda: smallest_side / width, | |
lambda: smallest_side / height) | |
new_height = tf.to_int32(height * scale) | |
new_width = tf.to_int32(width * scale) | |
resized_image = tf.image.resize_images(image, [new_height, new_width]) # (2) | |
return resized_image, label | |
# Preprocessing (for training) | |
# (3) Take a random 224x224 crop to the scaled image | |
# (4) Horizontally flip the image with probability 1/2 | |
# (5) Substract the per color mean `VGG_MEAN` | |
# Note: we don't normalize the data here, as VGG was trained without normalization | |
def training_preprocess(image, label): | |
crop_image = tf.random_crop(image, [224, 224, 3]) # (3) | |
flip_image = tf.image.random_flip_left_right(crop_image) # (4) | |
means = tf.reshape(tf.constant(VGG_MEAN), [1, 1, 3]) | |
centered_image = flip_image - means # (5) | |
return centered_image, label | |
# Preprocessing (for validation) | |
# (3) Take a central 224x224 crop to the scaled image | |
# (4) Substract the per color mean `VGG_MEAN` | |
# Note: we don't normalize the data here, as VGG was trained without normalization | |
def val_preprocess(image, label): | |
crop_image = tf.image.resize_image_with_crop_or_pad(image, 224, 224) # (3) | |
means = tf.reshape(tf.constant(VGG_MEAN), [1, 1, 3]) | |
centered_image = crop_image - means # (4) | |
return centered_image, label | |
# ---------------------------------------------------------------------- | |
# DATASET CREATION using tf.contrib.data.Dataset | |
# https://github.com/tensorflow/tensorflow/tree/master/tensorflow/contrib/data | |
# The tf.contrib.data.Dataset framework uses queues in the background to feed in | |
# data to the model. | |
# We initialize the dataset with a list of filenames and labels, and then apply | |
# the preprocessing functions described above. | |
# Behind the scenes, queues will load the filenames, preprocess them with multiple | |
# threads and apply the preprocessing in parallel, and then batch the data | |
# Training dataset | |
train_dataset = tf.contrib.data.Dataset.from_tensor_slices((train_filenames, train_labels)) | |
train_dataset = train_dataset.map(_parse_function, | |
num_threads=args.num_workers, output_buffer_size=args.batch_size) | |
train_dataset = train_dataset.map(training_preprocess, | |
num_threads=args.num_workers, output_buffer_size=args.batch_size) | |
train_dataset = train_dataset.shuffle(buffer_size=10000) # don't forget to shuffle | |
batched_train_dataset = train_dataset.batch(args.batch_size) | |
# Validation dataset | |
val_dataset = tf.contrib.data.Dataset.from_tensor_slices((val_filenames, val_labels)) | |
val_dataset = val_dataset.map(_parse_function, | |
num_threads=args.num_workers, output_buffer_size=args.batch_size) | |
val_dataset = val_dataset.map(val_preprocess, | |
num_threads=args.num_workers, output_buffer_size=args.batch_size) | |
batched_val_dataset = val_dataset.batch(args.batch_size) | |
# Now we define an iterator that can operator on either dataset. | |
# The iterator can be reinitialized by calling: | |
# - sess.run(train_init_op) for 1 epoch on the training set | |
# - sess.run(val_init_op) for 1 epoch on the valiation set | |
# Once this is done, we don't need to feed any value for images and labels | |
# as they are automatically pulled out from the iterator queues. | |
# A reinitializable iterator is defined by its structure. We could use the | |
# `output_types` and `output_shapes` properties of either `train_dataset` | |
# or `validation_dataset` here, because they are compatible. | |
iterator = tf.contrib.data.Iterator.from_structure(batched_train_dataset.output_types, | |
batched_train_dataset.output_shapes) | |
images, labels = iterator.get_next() | |
train_init_op = iterator.make_initializer(batched_train_dataset) | |
val_init_op = iterator.make_initializer(batched_val_dataset) | |
# Indicates whether we are in training or in test mode | |
is_training = tf.placeholder(tf.bool) | |
# --------------------------------------------------------------------- | |
# Now that we have set up the data, it's time to set up the model. | |
# For this example, we'll use VGG-16 pretrained on ImageNet. We will remove the | |
# last fully connected layer (fc8) and replace it with our own, with an | |
# output size num_classes=8 | |
# We will first train the last layer for a few epochs. | |
# Then we will train the entire model on our dataset for a few epochs. | |
# Get the pretrained model, specifying the num_classes argument to create a new | |
# fully connected replacing the last one, called "vgg_16/fc8" | |
# Each model has a different architecture, so "vgg_16/fc8" will change in another model. | |
# Here, logits gives us directly the predicted scores we wanted from the images. | |
# We pass a scope to initialize "vgg_16/fc8" weights with he_initializer | |
vgg = tf.contrib.slim.nets.vgg | |
with slim.arg_scope(vgg.vgg_arg_scope(weight_decay=args.weight_decay)): | |
logits, _ = vgg.vgg_16(images, num_classes=num_classes, is_training=is_training, | |
dropout_keep_prob=args.dropout_keep_prob) | |
# Specify where the model checkpoint is (pretrained weights). | |
model_path = args.model_path | |
assert(os.path.isfile(model_path)) | |
# Restore only the layers up to fc7 (included) | |
# Calling function `init_fn(sess)` will load all the pretrained weights. | |
variables_to_restore = tf.contrib.framework.get_variables_to_restore(exclude=['vgg_16/fc8']) | |
init_fn = tf.contrib.framework.assign_from_checkpoint_fn(model_path, variables_to_restore) | |
# Initialization operation from scratch for the new "fc8" layers | |
# `get_variables` will only return the variables whose name starts with the given pattern | |
fc8_variables = tf.contrib.framework.get_variables('vgg_16/fc8') | |
fc8_init = tf.variables_initializer(fc8_variables) | |
# --------------------------------------------------------------------- | |
# Using tf.losses, any loss is added to the tf.GraphKeys.LOSSES collection | |
# We can then call the total loss easily | |
tf.losses.sparse_softmax_cross_entropy(labels=labels, logits=logits) | |
loss = tf.losses.get_total_loss() | |
# First we want to train only the reinitialized last layer fc8 for a few epochs. | |
# We run minimize the loss only with respect to the fc8 variables (weight and bias). | |
fc8_optimizer = tf.train.GradientDescentOptimizer(args.learning_rate1) | |
fc8_train_op = fc8_optimizer.minimize(loss, var_list=fc8_variables) | |
# Then we want to finetune the entire model for a few epochs. | |
# We run minimize the loss only with respect to all the variables. | |
full_optimizer = tf.train.GradientDescentOptimizer(args.learning_rate2) | |
full_train_op = full_optimizer.minimize(loss) | |
# Evaluation metrics | |
prediction = tf.to_int32(tf.argmax(logits, 1)) | |
correct_prediction = tf.equal(prediction, labels) | |
accuracy = tf.reduce_mean(tf.cast(correct_prediction, tf.float32)) | |
tf.get_default_graph().finalize() | |
# -------------------------------------------------------------------------- | |
# Now that we have built the graph and finalized it, we define the session. | |
# The session is the interface to *run* the computational graph. | |
# We can call our training operations with `sess.run(train_op)` for instance | |
with tf.Session(graph=graph) as sess: | |
init_fn(sess) # load the pretrained weights | |
sess.run(fc8_init) # initialize the new fc8 layer | |
# Update only the last layer for a few epochs. | |
for epoch in range(args.num_epochs1): | |
# Run an epoch over the training data. | |
print('Starting epoch %d / %d' % (epoch + 1, args.num_epochs1)) | |
# Here we initialize the iterator with the training set. | |
# This means that we can go through an entire epoch until the iterator becomes empty. | |
sess.run(train_init_op) | |
while True: | |
try: | |
_ = sess.run(fc8_train_op, {is_training: True}) | |
except tf.errors.OutOfRangeError: | |
break | |
# Check accuracy on the train and val sets every epoch. | |
train_acc = check_accuracy(sess, correct_prediction, is_training, train_init_op) | |
val_acc = check_accuracy(sess, correct_prediction, is_training, val_init_op) | |
print('Train accuracy: %f' % train_acc) | |
print('Val accuracy: %f\n' % val_acc) | |
# Train the entire model for a few more epochs, continuing with the *same* weights. | |
for epoch in range(args.num_epochs2): | |
print('Starting epoch %d / %d' % (epoch + 1, args.num_epochs2)) | |
sess.run(train_init_op) | |
while True: | |
try: | |
_ = sess.run(full_train_op, {is_training: True}) | |
except tf.errors.OutOfRangeError: | |
break | |
# Check accuracy on the train and val sets every epoch | |
train_acc = check_accuracy(sess, correct_prediction, is_training, train_init_op) | |
val_acc = check_accuracy(sess, correct_prediction, is_training, val_init_op) | |
print('Train accuracy: %f' % train_acc) | |
print('Val accuracy: %f\n' % val_acc) | |
if __name__ == '__main__': | |
args = parser.parse_args() | |
main(args) |
@edwardnguyen1705, hehe, good for you!
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To whom it may concern, after a haft of a day, I finally found the one I was looking for( I apologize @omoindrot in advance. Because i am going to post some other github account here)
https://github.com/machrisaa/tensorflow-vgg/blob/master/vgg16.py -
If you want to get only extract_layers (conv4_3, conv4_2) like me:
Just use:
vgg = VGG16() conv4_3 = sess.run(vgg.conv4_3, feed_dict=feed_dict)
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If you just want to fine tune:
Get the the fully connected layer by its name ('fc7': vgg.fc7)
Then fine tuning your self.
Cheers!
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@VyBui After that day, I switch to use Pytorch.