tf_imagecoder.py

class ImageCoder(object):
  """Helper class for handling images in TensorFlow."""

  def __init__(self, channels=3, config=None):
    # Create a single TensorFlow Session for all image decoding calls.
    self._sess = tf.Session(config=config)

    # TensorFlow ops for JPEG decoding.
    self._src_png = tf.placeholder(dtype=tf.string)
    self._dst_raw = tf.image.decode_png(self._src_png, channels=channels)

    self._src_raw = tf.placeholder(dtype=tf.uint8)
    self._dst_png = tf.image.encode_png(self._src_raw)

  def decode_png(self, src_png):
    image = self._sess.run(self._dst_raw, {self._src_png: src_png})
    return image
  
  def encode_png(self, src_raw):
    image_png = self._sess.run(self._dst_png, {self._src_raw: src_raw})
    return image_png