create_imdb.py

"""--------------------------------------------------------------------------------------------------------------------------------------------------
REFERENCE:
----------
Code adapted from Google Tensor FLow Git Hub Repositiory:
https://github.com/tensorflow/models/blob/f87a58cd96d45de73c9a8330a06b2ab56749a7fa/research/inception/inception/data/build_image_data.py 

    @author: Oluwole Oyetoke
    @date: 5th December, 2017
    @langauge: Python/TF
    @email: oluwoleoyetoke@gmail.com

INTRODUCTION:
-------------
Converts image dataset to a sharded dataset. The sharded dataset consists of Tensor Flow Records Format (TFRecords) and with Example protos.
  train_directory/train-00000-of-01024
  train_directory/train-00001-of-01024
  ...
  train_directory/train-01023-of-01024
and
  validation_directory/validation-00000-of-00128
  validation_directory/validation-00001-of-00128
  ...
  validation_directory/validation-00127-of-00128

EXPECTATIONS:
------------
1. Image data set should be in .jpeg format
2. It is adviced that you have only folders in the base directory containing your training images."
   "Base folder-->Subfolders-->Each subfolder containing specific classes of image."
   "E.g Training Folder -> stop_sign_folder -> 1.jpg, 2.jpg, 3.jpg....";
   (data_dir/label_0/image0.jpeg
   (data_dir/label_0/image1.jpg)
3.The sub-directory should be the unique label associated with the images in the folder.


SHARDS CONTENT:
--------------
Where we have selected [x] number of image files per training dataset shard and [y] number of image files per evaluation dataset shard,
for each of the shards, each record within the TFRecord file (shard) is a serialized example proto consisting of the following fields:
  image/encoded:    string containing JPEG encoded image in RGB colorspace
  image/height:     integer, image height in pixels
  image/width:      integer, image width in pixels
  image/colorspace: string, specifying the colorspace, always 'RGB'
  image/channels:   integer, specifying the number of channels, always 3
  image/format:     string, specifying the format, always 'JPEG'
  image/filename:   string containing the basename of the image file e.g. 'n01440764_10026.JPEG' or 'ILSVRC2012_val_00000293.JPEG'
  image/class/label:integer specifying the index in a classification layer. The label ranges from [0, num_labels] where 0 is unused and left as the background class.
  image/class/text: string specifying the human-readable version of the label e.g. 'dog'
If your data set involves bounding boxes, please look at build_imagenet_data.py.




#IMPORTS
-------------------------------------------------------------------------------------------------------------------------------------------------------"""
from __future__ import absolute_import
from __future__ import division
from __future__ import print_function

from datetime import datetime
from PIL import Image
from time import sleep
import os
import random
import sys
import threading

import numpy as np
import tensorflow as tf
"""-------------------------------------------------------------------------------------------------------------------------------------------------------"""




# SETTING SOME GLOBAL DATA
"""-------------------------------------------------------------------------------------------------------------------------------------------------------"""
tf.app.flags.DEFINE_string('train_directory', '/home/olu/Dev/data_base/sign_base/training_227x227', 'Training data directory')
tf.app.flags.DEFINE_string('validation_directory', '/home/olu/Dev/data_base/sign_base/training_227x227', 'Validation data directory')
tf.app.flags.DEFINE_string('output_directory', '/home/olu/Dev/data_base/sign_base/output/TFRecord_227x227', 'Output data directory')
tf.app.flags.DEFINE_integer('train_shards', 2, 'Number of shards in training TFRecord files.')
tf.app.flags.DEFINE_integer('validation_shards', 2, 'Number of shards in validation TFRecord files.')
tf.app.flags.DEFINE_integer('num_threads', 2, 'Number of threads to preprocess the images.')
tf.app.flags.DEFINE_string('labels_file', '/home/olu/Dev/data_base/sign_base/labels.txt', 'Labels_file.txt')
tf.app.flags.DEFINE_integer("image_height", 227, "Height of the output image after crop and resize.") #Alexnet takes 227 x 227 image input
tf.app.flags.DEFINE_integer("image_width", 227, "Width of the output image after crop and resize.")
FLAGS = tf.app.flags.FLAGS
""" The labels file contains a list of valid labels are held in this file. The file contains entries such as:
        speed_100
        speed_120
        no_car_overtaking
        no_truck_overtaking
    Each line corresponds to a label, and each label (per line) is mapped to an integer corresponding to the line number starting from 0.


-------------------------------------------------------------------------------------------------------------------------------------------------------"""




# WRAPPER FOR INSERTING int64 FEATURES int64 FEATURES & BYTES FEATURES INTO EXAMPLES PROTO
"""-------------------------------------------------------------------------------------------------------------------------------------------------------"""
def _int64_feature(value):
  if not isinstance(value, list):
    value = [value]
  return tf.train.Feature(int64_list=tf.train.Int64List(value=value))

def _bytes_feature(value):
  return tf.train.Feature(bytes_list=tf.train.BytesList(value=[value]))
"""-------------------------------------------------------------------------------------------------------------------------------------------------------"""





#FUNCTION FOR BUILDING A PROTO
"""-------------------------------------------------------------------------------------------------------------------------------------------------------"""
def _convert_to_example(filename, image_buffer, label, text, shape_buffer):
  """Build an Example proto for an example.
  Args:
    filename: string, path to an image file, e.g., '/path/to/example.JPG'
    image_buffer: string, JPEG encoding of RGB image
    label: integer, identifier for the ground truth for the network
    text: string, unique human-readable, e.g. 'dog'
    height: integer, image height in pixels
    width: integer, image width in pixels
  Returns:
    Example proto
  """

  colorspace = 'RGB'
  channels = 3
  image_format = 'JPEG'
  #Save TFrecord containing image_bytes, shape [337,337,3], label, text, filename
  example = tf.train.Example(features=tf.train.Features(feature={
      'image/shape': _bytes_feature(shape_buffer), 
      'image/class/label': _int64_feature(label),
      'image/class/text': _bytes_feature(tf.compat.as_bytes(text)),
      'image/filename': _bytes_feature(tf.compat.as_bytes(os.path.basename(filename))),
      'image/encoded': _bytes_feature(image_buffer)}))
  return example
"""-------------------------------------------------------------------------------------------------------------------------------------------------------"""




#CLASS WIH FUNCTIONS TO HELP ENCODE & DECODE IMAGES
"""-------------------------------------------------------------------------------------------------------------------------------------------------------"""
class ImageCoder(object):

  def __init__(self):
    # Create a single Session to run all image coding calls.
    self._sess = tf.Session()

    # Initializes function that converts PNG to JPEG data.
    self._png_data = tf.placeholder(dtype=tf.string)
    image = tf.image.decode_png(self._png_data, channels=3)
    self._png_to_jpeg = tf.image.encode_jpeg(image, format='rgb', quality=100)

    # Initializes function that decodes RGB JPEG data.
    self._decode_jpeg_data = tf.placeholder(dtype=tf.string)
    self._decode_jpeg = tf.image.decode_jpeg(self._decode_jpeg_data, channels=3)

  def png_to_jpeg(self, image_data):
    return self._sess.run(self._png_to_jpeg,
                          feed_dict={self._png_data: image_data})

  def decode_jpeg(self, image_data):
    image = self._sess.run(self._decode_jpeg,
                           feed_dict={self._decode_jpeg_data: image_data})
    assert len(image.shape) == 3
    assert image.shape[2] == 3
    return image
"""-------------------------------------------------------------------------------------------------------------------------------------------------------"""




# PRE-PROCESS SINGLE IMAGE(Check if PNG, convert to JPEG, confirm conversion)
"""-------------------------------------------------------------------------------------------------------------------------------------------------------"""
def _is_png(filename):
  """Determine if a file contains a PNG format image.
  Args:
    filename: string, path of the image file.
  Returns:
    boolean indicating if the image is a PNG.
  """
  return '.png' in filename


def _process_image(filename, coder):
  """Process a single image file.
  Args:
    filename: string, path to an image file e.g., '/path/to/example.JPG'.
    coder: instance of ImageCoder to provide TensorFlow image coding utils.
  Returns:
    image_buffer: string, JPEG encoding of RGB image.
    height: integer, image height in pixels.
    width: integer, image width in pixels.
  """
  #Resize image to networks input size
  size=(FLAGS.image_height, FLAGS.image_width)
  original_image = Image.open(filename)
  width, height = original_image.size
  #print('The original image size is {wide} wide x {height} high'.format(wide=width, height=height))
  
  resized_image = original_image.resize(size)
  width, height = resized_image.size
  #print('The resized image size is {wide} wide x {height} high'.format(wide=width, height=height))
  resized_image.save(filename)


  #Sleep a bit before file is re-read 5 milliseconds
  sleep(0.005)

  #ensure that all dataset images have been conveted to .jpeg
  image = np.asarray(original_image, np.uint8) #get image data
  shape = np.array(image.shape, np.int32) #get image shape
  shape_data = shape.tobytes() #convert image shape to bytes
  image_data = image.tobytes() # convert image to raw data bytes in the array.
  
  """ ANOTHER METHOD
  # Read the image file.
  with tf.gfile.FastGFile(filename, 'rb') as f:
    image_data = f.read()
    

  # Convert any PNG to JPEG's for consistency.
  if _is_png(filename):
    print('Converting PNG to JPEG for %s' % filename)
    image_data = coder.png_to_jpeg(image_data)

  # Decode the RGB JPEG.
  image = coder.decode_jpeg(image_data)

  # Check that image converted to RGB
  assert len(image.shape) == 3
  height = image.shape[0]
  width = image.shape[1]
  assert image.shape[2] == 3"""
  return image_data, shape_data
"""-------------------------------------------------------------------------------------------------------------------------------------------------------"""




# PROCESS BATCHES OF IMAGES AS AS EXAMPLE PROTO SAVED TO TFRecord PER SHARD
"""-------------------------------------------------------------------------------------------------------------------------------------------------------"""
def _process_image_files_batch(coder, thread_index, ranges, name, filenames,
                               texts, labels, num_shards):
  """Processes and saves list of images as TFRecord in 1 thread.
  Args:
    coder: instance of ImageCoder to provide TensorFlow image coding utils.
    thread_index: integer, unique batch to run index is within [0, len(ranges)).
    ranges: list of pairs of integers specifying ranges of each batches to
      analyze in parallel.
    name: string, unique identifier specifying the data set
    filenames: list of strings; each string is a path to an image file
    texts: list of strings; each string is human readable, e.g. 'dog'
    labels: list of integer; each integer identifies the ground truth
    num_shards: integer number of shards for this data set.
  """
  # Each thread produces N shards where N = int(num_shards / num_threads).
  # For instance, if num_shards = 128, and the num_threads = 2, then the first
  # thread would produce shards [0, 64).
  num_threads = len(ranges)
  assert not num_shards % num_threads
  num_shards_per_batch = int(num_shards / num_threads) #Same as number of shards per thread

  shard_ranges = np.linspace(ranges[thread_index][0],
                             ranges[thread_index][1],
                             num_shards_per_batch + 1).astype(int)
  num_files_in_thread = ranges[thread_index][1] - ranges[thread_index][0]

  counter = 0
  for s in range(num_shards_per_batch):
    # Generate a sharded version of the file name, e.g. 'train-00002-of-00010'
    shard = thread_index * num_shards_per_batch + s
    output_filename = '%s-%.5d-of-%.5d' % (name, shard, num_shards)
    output_file = os.path.join(FLAGS.output_directory, output_filename)
    writer = tf.python_io.TFRecordWriter(output_file)

    shard_counter = 0
    files_in_shard = np.arange(shard_ranges[s], shard_ranges[s + 1], dtype=int)
    for i in files_in_shard:
      filename = filenames[i]
      label = labels[i]
      text = texts[i]

      try:
       # image_buffer, height, width = _process_image(filename, coder)
        image_buffer, shape_buffer = _process_image(filename, coder)
      except Exception as e:
        print(e)
        print('SKIPPED: Unexpected eror while decoding %s.' % filename)
        continue

      example = _convert_to_example(filename, image_buffer, label,
                                    text, shape_buffer)
      writer.write(example.SerializeToString())
      shard_counter += 1
      counter += 1

      if not counter % 1000:
        print('%s [thread %d]: Processed %d of %d images in thread batch.' %
              (datetime.now(), thread_index, counter, num_files_in_thread))
        sys.stdout.flush()

    writer.close()
    print('%s [thread %d]: Wrote %d images to %s' %
          (datetime.now(), thread_index, shard_counter, output_file))
    sys.stdout.flush()
    shard_counter = 0
  print('%s [thread %d]: Wrote %d images to %d shards.' %
        (datetime.now(), thread_index, counter, num_files_in_thread))
  sys.stdout.flush()
"""-------------------------------------------------------------------------------------------------------------------------------------------------------"""




# PROCESS AND SAVES LIST OF IMAGES AS TFRecord OF EXAMPLE PROTOS (Entire Dataset details sent here)
"""-------------------------------------------------------------------------------------------------------------------------------------------------------"""
def _process_image_files(name, filenames, texts, labels, num_shards):
  """Process and save list of images as TFRecord of Example protos.
  Args:
    name: string, unique identifier specifying the data set
    filenames: list of strings; each string is a path to an image file
    texts: list of strings; each string is human readable, e.g. 'dog'
    labels: list of integer; each integer identifies the ground truth
    num_shards: integer number of shards for this data set.
  """
  assert len(filenames) == len(texts)
  assert len(filenames) == len(labels)

  # Break all images into batches with a [ranges[i][0], ranges[i][1]].
  spacing = np.linspace(0, len(filenames), FLAGS.num_threads + 1).astype(np.int)
  ranges = []
  for i in range(len(spacing) - 1):
    ranges.append([spacing[i], spacing[i + 1]])

  # Launch a thread for each batch.
  print('Launching %d threads for spacings: %s' % (FLAGS.num_threads, ranges))
  sys.stdout.flush()

  # Create a mechanism for monitoring when all threads are finished.
  coord = tf.train.Coordinator()

  # Create a generic TensorFlow-based utility for converting all image codings.
  coder = ImageCoder()

  threads = []
  for thread_index in range(len(ranges)):
    args = (coder, thread_index, ranges, name, filenames,
            texts, labels, num_shards)
    #From the entire data set details sent to _process_image_files, convert then to proto examples in batches (per no of threads set) and save as TFRecord
    t = threading.Thread(target=_process_image_files_batch, args=args) 
    t.start()
    threads.append(t)

  # Wait for all the threads to terminate.
  coord.join(threads)
  print('%s: Finished writing all %d images in data set.' %
        (datetime.now(), len(filenames)))
  sys.stdout.flush()
"""-------------------------------------------------------------------------------------------------------------------------------------------------------"""





#BUILD LIST OF ALL IMAGES FILES AND LABELS IN THE DATA SET
"""-------------------------------------------------------------------------------------------------------------------------------------------------------"""
def _find_image_files(data_dir, labels_file):
  """
  Args:
    data_dir: string, path to the root directory of images.
      Assumes that the image data set resides in JPEG files located in
      the following directory structure.
        data_dir/dog/another-image.JPEG
        data_dir/dog/my-image.jpg
      where 'dog' is the label associated with these images.
    labels_file: string, path to the labels file.
      The list of valid labels are held in this file. Assumes that the file
      contains entries as such:
        dog
        cat
        flower
      where each line corresponds to a label. We map each label contained in
      the file to an integer starting with the integer 0 corresponding to the
      label contained in the first line.
  Returns:
    filenames: list of strings; each string is a path to an image file.
    texts: list of strings; each string is the class, e.g. 'dog'
    labels: list of integer; each integer identifies the ground truth.
  """
  print('Determining list of input files and labels from %s ' % labels_file)
  unique_labels = [l.strip() for l in tf.gfile.FastGFile(
      labels_file, 'r').readlines()]

  labels = []
  filenames = []
  texts = []

  # Leave label index 0 empty as a background class.
  label_index = 1

  # Construct the list of JPEG files and labels.
  for text in unique_labels:
    jpeg_file_path = '%s/%s/*' % (data_dir, text)
    print("File path %s \n" % jpeg_file_path);
    matching_files = tf.gfile.Glob(jpeg_file_path)

    labels.extend([label_index] * len(matching_files))
    texts.extend([text] * len(matching_files))
    filenames.extend(matching_files)

    if not label_index % 100:
      print('Finished finding files in %d of %d classes.' % (
          label_index, len(labels)))
    label_index += 1

  # Shuffle the ordering of all image files in order to guarantee
  # random ordering of the images with respect to label in the
  # saved TFRecord files. Make the randomization repeatable.
  shuffled_index = list(range(len(filenames)))
  random.seed(12345)
  random.shuffle(shuffled_index)

  filenames = [filenames[i] for i in shuffled_index]
  texts = [texts[i] for i in shuffled_index]
  labels = [labels[i] for i in shuffled_index]

  print('Found %d JPEG files across %d labels inside %s' %
        (len(filenames), len(unique_labels), data_dir))
  return filenames, texts, labels
"""-------------------------------------------------------------------------------------------------------------------------------------------------------"""



#CALL TO PROCESS DATASET IS MADE HERE
"""-------------------------------------------------------------------------------------------------------------------------------------------------------"""
def _process_dataset(name, directory, num_shards, labels_file):
  """Process a complete data set and save it as a TFRecord.
  Args:
    name: string, unique identifier specifying the data set.
    directory: string, root path to the data set.
    num_shards: integer number of shards for this data set.
    labels_file: string, path to the labels file.
  """
  filenames, texts, labels = _find_image_files(directory, labels_file)  #Build list of dataset image file (path to them) and their labels as string and integer
  _process_image_files(name, filenames, texts, labels, num_shards)      #Process the entire list of images in the dataset into a TF record
"""-------------------------------------------------------------------------------------------------------------------------------------------------------"""



#MAIN
"""-------------------------------------------------------------------------------------------------------------------------------------------------------"""
def main(unused_argv):
  assert not FLAGS.train_shards % FLAGS.num_threads, ('Please make the FLAGS.num_threads commensurate with FLAGS.train_shards')
  assert not FLAGS.validation_shards % FLAGS.num_threads, ('Please make the FLAGS.num_threads commensurate with ''FLAGS.validation_shards')
  print('Result will be saved to %s' % FLAGS.output_directory)

  # Run it!
  _process_dataset('validation', FLAGS.validation_directory, FLAGS.validation_shards, FLAGS.labels_file)
  _process_dataset('train', FLAGS.train_directory, FLAGS.train_shards, FLAGS.labels_file)


if __name__ == '__main__':
  tf.app.run()

"""-------------------------------------------------------------------------------------------------------------------------------------------------------"""